ホーム エクスプローラ ヘルプ
登録 サインイン
Java-Util
/
hk-sdk-demo
2
0
フォーク 0
ファイル 課題 0 プルリクエスト 0 Wiki
ツリー: 5794bec228
ブランチ タグ
hk-sdk-demo
/
ffmpeg
/
doc
/
ffmpeg-codecs.html

ffmpeg-codecs.html 218 KB
履歴 Raw

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991001011021031041051061071081091101111121131141151161171181191201211221231241251261271281291301311321331341351361371381391401411421431441451461471481491501511521531541551561571581591601611621631641651661671681691701711721731741751761771781791801811821831841851861871881891901911921931941951961971981992002012022032042052062072082092102112122132142152162172182192202212222232242252262272282292302312322332342352362372382392402412422432442452462472482492502512522532542552562572582592602612622632642652662672682692702712722732742752762772782792802812822832842852862872882892902912922932942952962972982993003013023033043053063073083093103113123133143153163173183193203213223233243253263273283293303313323333343353363373383393403413423433443453463473483493503513523533543553563573583593603613623633643653663673683693703713723733743753763773783793803813823833843853863873883893903913923933943953963973983994004014024034044054064074084094104114124134144154164174184194204214224234244254264274284294304314324334344354364374384394404414424434444454464474484494504514524534544554564574584594604614624634644654664674684694704714724734744754764774784794804814824834844854864874884894904914924934944954964974984995005015025035045055065075085095105115125135145155165175185195205215225235245255265275285295305315325335345355365375385395405415425435445455465475485495505515525535545555565575585595605615625635645655665675685695705715725735745755765775785795805815825835845855865875885895905915925935945955965975985996006016026036046056066076086096106116126136146156166176186196206216226236246256266276286296306316326336346356366376386396406416426436446456466476486496506516526536546556566576586596606616626636646656666676686696706716726736746756766776786796806816826836846856866876886896906916926936946956966976986997007017027037047057067077087097107117127137147157167177187197207217227237247257267277287297307317327337347357367377387397407417427437447457467477487497507517527537547557567577587597607617627637647657667677687697707717727737747757767777787797807817827837847857867877887897907917927937947957967977987998008018028038048058068078088098108118128138148158168178188198208218228238248258268278288298308318328338348358368378388398408418428438448458468478488498508518528538548558568578588598608618628638648658668678688698708718728738748758768778788798808818828838848858868878888898908918928938948958968978988999009019029039049059069079089099109119129139149159169179189199209219229239249259269279289299309319329339349359369379389399409419429439449459469479489499509519529539549559569579589599609619629639649659669679689699709719729739749759769779789799809819829839849859869879889899909919929939949959969979989991000100110021003100410051006100710081009101010111012101310141015101610171018101910201021102210231024102510261027102810291030103110321033103410351036103710381039104010411042104310441045104610471048104910501051105210531054105510561057105810591060106110621063106410651066106710681069107010711072107310741075107610771078107910801081108210831084108510861087108810891090109110921093109410951096109710981099110011011102110311041105110611071108110911101111111211131114111511161117111811191120112111221123112411251126112711281129113011311132113311341135113611371138113911401141114211431144114511461147114811491150115111521153115411551156115711581159116011611162116311641165116611671168116911701171117211731174117511761177117811791180118111821183118411851186118711881189119011911192119311941195119611971198119912001201120212031204120512061207120812091210121112121213121412151216121712181219122012211222122312241225122612271228122912301231123212331234123512361237123812391240124112421243124412451246124712481249125012511252125312541255125612571258125912601261126212631264126512661267126812691270127112721273127412751276127712781279128012811282128312841285128612871288128912901291129212931294129512961297129812991300130113021303130413051306130713081309131013111312131313141315131613171318131913201321132213231324132513261327132813291330133113321333133413351336133713381339134013411342134313441345134613471348134913501351135213531354135513561357135813591360136113621363136413651366136713681369137013711372137313741375137613771378137913801381138213831384138513861387138813891390139113921393139413951396139713981399140014011402140314041405140614071408140914101411141214131414141514161417141814191420142114221423142414251426142714281429143014311432143314341435143614371438143914401441144214431444144514461447144814491450145114521453145414551456145714581459146014611462146314641465146614671468146914701471147214731474147514761477147814791480148114821483148414851486148714881489149014911492149314941495149614971498149915001501150215031504150515061507150815091510151115121513151415151516151715181519152015211522152315241525152615271528152915301531153215331534153515361537153815391540154115421543154415451546154715481549155015511552155315541555155615571558155915601561156215631564156515661567156815691570157115721573157415751576157715781579158015811582158315841585158615871588158915901591159215931594159515961597159815991600160116021603160416051606160716081609161016111612161316141615161616171618161916201621162216231624162516261627162816291630163116321633163416351636163716381639164016411642164316441645164616471648164916501651165216531654165516561657165816591660166116621663166416651666166716681669167016711672167316741675167616771678167916801681168216831684168516861687168816891690169116921693169416951696169716981699170017011702170317041705170617071708170917101711171217131714171517161717171817191720172117221723172417251726172717281729173017311732173317341735173617371738173917401741174217431744174517461747174817491750175117521753175417551756175717581759176017611762176317641765176617671768176917701771177217731774177517761777177817791780178117821783178417851786178717881789179017911792179317941795179617971798179918001801180218031804180518061807180818091810181118121813181418151816181718181819182018211822182318241825182618271828182918301831183218331834183518361837183818391840184118421843184418451846184718481849185018511852185318541855185618571858185918601861186218631864186518661867186818691870187118721873187418751876187718781879188018811882188318841885188618871888188918901891189218931894189518961897189818991900190119021903190419051906190719081909191019111912191319141915191619171918191919201921192219231924192519261927192819291930193119321933193419351936193719381939194019411942194319441945194619471948194919501951195219531954195519561957195819591960196119621963196419651966196719681969197019711972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005200620072008200920102011201220132014201520162017201820192020202120222023202420252026202720282029203020312032203320342035203620372038203920402041204220432044204520462047204820492050205120522053205420552056205720582059206020612062206320642065206620672068206920702071207220732074207520762077207820792080208120822083208420852086208720882089209020912092209320942095209620972098209921002101210221032104210521062107210821092110211121122113211421152116211721182119212021212122212321242125212621272128212921302131213221332134213521362137213821392140214121422143214421452146214721482149215021512152215321542155215621572158215921602161216221632164216521662167216821692170217121722173217421752176217721782179218021812182218321842185218621872188218921902191219221932194219521962197219821992200220122022203220422052206220722082209221022112212221322142215221622172218221922202221222222232224222522262227222822292230223122322233223422352236223722382239224022412242224322442245224622472248224922502251225222532254225522562257225822592260226122622263226422652266226722682269227022712272227322742275227622772278227922802281228222832284228522862287228822892290229122922293229422952296229722982299230023012302230323042305230623072308230923102311231223132314231523162317231823192320232123222323232423252326232723282329233023312332233323342335233623372338233923402341234223432344234523462347234823492350235123522353235423552356235723582359236023612362236323642365236623672368236923702371237223732374237523762377237823792380238123822383238423852386238723882389239023912392239323942395239623972398239924002401240224032404240524062407240824092410241124122413241424152416241724182419242024212422242324242425242624272428242924302431243224332434243524362437243824392440244124422443244424452446244724482449245024512452245324542455245624572458245924602461246224632464246524662467246824692470247124722473247424752476247724782479248024812482248324842485248624872488248924902491249224932494249524962497249824992500250125022503250425052506250725082509251025112512251325142515251625172518251925202521252225232524252525262527252825292530253125322533253425352536253725382539254025412542254325442545254625472548254925502551255225532554255525562557255825592560256125622563256425652566256725682569257025712572257325742575257625772578257925802581258225832584258525862587258825892590259125922593259425952596259725982599260026012602260326042605260626072608260926102611261226132614261526162617261826192620262126222623262426252626262726282629263026312632263326342635263626372638263926402641264226432644264526462647264826492650265126522653265426552656265726582659266026612662266326642665266626672668266926702671267226732674267526762677267826792680268126822683268426852686268726882689269026912692269326942695269626972698269927002701270227032704270527062707270827092710271127122713271427152716271727182719272027212722272327242725272627272728272927302731273227332734273527362737273827392740274127422743274427452746274727482749275027512752275327542755275627572758275927602761276227632764276527662767276827692770277127722773277427752776277727782779278027812782278327842785278627872788278927902791279227932794279527962797279827992800280128022803280428052806280728082809281028112812281328142815281628172818281928202821282228232824282528262827282828292830283128322833283428352836283728382839284028412842284328442845284628472848284928502851285228532854285528562857285828592860286128622863286428652866286728682869287028712872287328742875287628772878287928802881288228832884288528862887288828892890289128922893289428952896289728982899290029012902290329042905290629072908290929102911291229132914291529162917291829192920292129222923292429252926292729282929293029312932293329342935293629372938293929402941294229432944294529462947294829492950295129522953295429552956295729582959296029612962296329642965296629672968296929702971297229732974297529762977297829792980298129822983298429852986298729882989299029912992299329942995299629972998299930003001300230033004300530063007300830093010301130123013301430153016301730183019302030213022302330243025302630273028302930303031303230333034303530363037303830393040304130423043304430453046304730483049305030513052305330543055305630573058305930603061306230633064306530663067306830693070307130723073307430753076307730783079308030813082308330843085308630873088308930903091309230933094309530963097309830993100310131023103310431053106310731083109311031113112311331143115311631173118311931203121312231233124312531263127312831293130313131323133313431353136313731383139314031413142314331443145314631473148314931503151315231533154315531563157315831593160316131623163316431653166316731683169317031713172317331743175317631773178317931803181318231833184318531863187318831893190319131923193319431953196319731983199320032013202320332043205320632073208320932103211321232133214321532163217321832193220322132223223322432253226322732283229323032313232323332343235323632373238323932403241324232433244324532463247324832493250325132523253325432553256325732583259326032613262326332643265326632673268326932703271327232733274327532763277327832793280328132823283328432853286328732883289329032913292329332943295329632973298329933003301330233033304330533063307330833093310331133123313331433153316331733183319332033213322332333243325332633273328332933303331333233333334333533363337333833393340334133423343334433453346334733483349335033513352335333543355335633573358335933603361336233633364336533663367336833693370337133723373337433753376337733783379338033813382338333843385338633873388338933903391339233933394339533963397339833993400340134023403340434053406340734083409341034113412341334143415341634173418341934203421342234233424342534263427342834293430343134323433343434353436343734383439344034413442344334443445344634473448344934503451345234533454345534563457345834593460346134623463346434653466346734683469347034713472347334743475347634773478347934803481348234833484348534863487348834893490349134923493349434953496349734983499350035013502350335043505350635073508350935103511351235133514351535163517351835193520352135223523352435253526352735283529353035313532353335343535353635373538353935403541354235433544354535463547354835493550355135523553355435553556355735583559356035613562356335643565356635673568356935703571357235733574357535763577357835793580358135823583358435853586358735883589359035913592359335943595359635973598359936003601360236033604360536063607360836093610361136123613361436153616361736183619362036213622362336243625362636273628362936303631363236333634363536363637363836393640364136423643364436453646364736483649365036513652365336543655365636573658365936603661366236633664366536663667366836693670367136723673367436753676367736783679368036813682368336843685368636873688368936903691369236933694369536963697369836993700370137023703370437053706370737083709371037113712371337143715371637173718371937203721372237233724372537263727372837293730373137323733373437353736373737383739374037413742374337443745374637473748374937503751375237533754375537563757375837593760376137623763376437653766376737683769377037713772377337743775377637773778377937803781378237833784378537863787378837893790379137923793379437953796379737983799380038013802380338043805380638073808380938103811381238133814381538163817381838193820382138223823382438253826382738283829383038313832383338343835383638373838383938403841384238433844384538463847384838493850385138523853385438553856385738583859386038613862386338643865386638673868386938703871387238733874387538763877387838793880388138823883388438853886388738883889389038913892389338943895389638973898389939003901390239033904390539063907390839093910391139123913391439153916391739183919392039213922392339243925392639273928392939303931393239333934393539363937393839393940394139423943394439453946394739483949395039513952395339543955395639573958395939603961396239633964396539663967396839693970397139723973397439753976397739783979398039813982398339843985398639873988398939903991399239933994399539963997399839994000400140024003400440054006400740084009401040114012401340144015401640174018401940204021402240234024402540264027402840294030403140324033403440354036403740384039404040414042404340444045404640474048404940504051405240534054405540564057405840594060406140624063406440654066406740684069407040714072407340744075407640774078407940804081408240834084408540864087408840894090409140924093409440954096409740984099410041014102410341044105410641074108410941104111411241134114411541164117411841194120412141224123412441254126412741284129413041314132413341344135413641374138413941404141414241434144414541464147414841494150415141524153415441554156415741584159416041614162416341644165416641674168416941704171417241734174417541764177417841794180418141824183418441854186418741884189419041914192419341944195419641974198419942004201420242034204420542064207420842094210421142124213421442154216421742184219422042214222422342244225422642274228422942304231423242334234423542364237423842394240424142424243424442454246424742484249425042514252425342544255425642574258425942604261426242634264426542664267426842694270427142724273427442754276427742784279428042814282428342844285428642874288428942904291429242934294429542964297429842994300430143024303430443054306430743084309431043114312431343144315431643174318431943204321432243234324432543264327432843294330433143324333433443354336433743384339434043414342434343444345434643474348434943504351435243534354435543564357435843594360436143624363436443654366436743684369437043714372437343744375437643774378437943804381438243834384438543864387438843894390439143924393439443954396439743984399440044014402440344044405440644074408440944104411441244134414441544164417441844194420442144224423442444254426442744284429443044314432443344344435443644374438443944404441444244434444444544464447444844494450445144524453445444554456445744584459446044614462446344644465446644674468446944704471447244734474447544764477447844794480448144824483448444854486448744884489449044914492449344944495449644974498449945004501450245034504450545064507450845094510451145124513451445154516451745184519452045214522452345244525452645274528452945304531453245334534453545364537453845394540454145424543454445454546454745484549455045514552455345544555455645574558455945604561456245634564456545664567456845694570457145724573457445754576457745784579458045814582458345844585458645874588458945904591459245934594459545964597459845994600460146024603460446054606460746084609461046114612461346144615461646174618461946204621462246234624462546264627462846294630463146324633463446354636463746384639464046414642464346444645464646474648464946504651465246534654465546564657465846594660466146624663466446654666466746684669467046714672467346744675467646774678467946804681468246834684468546864687468846894690469146924693469446954696469746984699470047014702470347044705470647074708470947104711471247134714471547164717471847194720472147224723472447254726472747284729473047314732473347344735473647374738473947404741474247434744474547464747474847494750475147524753475447554756475747584759476047614762476347644765476647674768476947704771477247734774477547764777477847794780478147824783478447854786478747884789479047914792479347944795479647974798479948004801480248034804480548064807480848094810481148124813481448154816481748184819482048214822482348244825482648274828482948304831483248334834483548364837483848394840484148424843484448454846484748484849485048514852485348544855485648574858485948604861486248634864486548664867486848694870487148724873487448754876487748784879488048814882488348844885488648874888488948904891489248934894489548964897489848994900490149024903490449054906490749084909491049114912491349144915491649174918491949204921492249234924492549264927492849294930493149324933493449354936493749384939494049414942494349444945494649474948494949504951495249534954495549564957495849594960496149624963496449654966496749684969497049714972497349744975497649774978497949804981498249834984498549864987498849894990499149924993499449954996499749984999500050015002500350045005500650075008500950105011501250135014501550165017501850195020502150225023502450255026502750285029503050315032503350345035503650375038503950405041504250435044504550465047504850495050505150525053505450555056505750585059506050615062506350645065506650675068506950705071507250735074507550765077507850795080508150825083508450855086508750885089509050915092509350945095509650975098509951005101510251035104510551065107510851095110511151125113511451155116511751185119512051215122512351245125512651275128512951305131513251335134513551365137513851395140514151425143514451455146514751485149515051515152515351545155515651575158515951605161516251635164516551665167516851695170517151725173517451755176517751785179518051815182518351845185518651875188518951905191519251935194519551965197519851995200520152025203520452055206520752085209521052115212521352145215521652175218521952205221522252235224522552265227522852295230523152325233523452355236523752385239524052415242524352445245524652475248524952505251525252535254525552565257525852595260526152625263526452655266526752685269527052715272527352745275527652775278527952805281528252835284528552865287528852895290529152925293529452955296529752985299530053015302530353045305530653075308530953105311531253135314531553165317531853195320532153225323532453255326532753285329533053315332533353345335533653375338533953405341534253435344534553465347534853495350535153525353535453555356535753585359536053615362536353645365536653675368536953705371537253735374537553765377537853795380538153825383538453855386538753885389539053915392539353945395539653975398539954005401540254035404540554065407540854095410541154125413541454155416541754185419542054215422542354245425542654275428542954305431543254335434543554365437543854395440544154425443544454455446544754485449545054515452545354545455545654575458545954605461546254635464546554665467546854695470547154725473547454755476547754785479548054815482548354845485548654875488548954905491549254935494549554965497549854995500550155025503550455055506550755085509551055115512551355145515551655175518551955205521552255235524552555265527552855295530553155325533553455355536553755385539554055415542554355445545554655475548554955505551555255535554555555565557555855595560556155625563556455655566556755685569557055715572557355745575557655775578557955805581558255835584558555865587558855895590559155925593559455955596559755985599560056015602560356045605560656075608560956105611561256135614561556165617561856195620562156225623562456255626562756285629563056315632563356345635563656375638563956405641564256435644564556465647564856495650565156525653565456555656565756585659566056615662566356645665566656675668566956705671567256735674567556765677567856795680568156825683568456855686568756885689569056915692569356945695569656975698569957005701570257035704570557065707570857095710571157125713571457155716571757185719572057215722572357245725572657275728572957305731573257335734573557365737573857395740574157425743574457455746574757485749575057515752575357545755575657575758575957605761576257635764576557665767576857695770577157725773577457755776577757785779578057815782578357845785578657875788578957905791579257935794579557965797579857995800580158025803580458055806580758085809581058115812581358145815581658175818581958205821582258235824582558265827582858295830583158325833583458355836583758385839584058415842584358445845584658475848584958505851585258535854585558565857585858595860586158625863586458655866586758685869587058715872587358745875587658775878587958805881588258835884588558865887588858895890589158925893589458955896589758985899590059015902590359045905590659075908590959105911591259135914591559165917591859195920592159225923592459255926592759285929593059315932593359345935593659375938593959405941594259435944594559465947594859495950595159525953595459555956595759585959596059615962596359645965596659675968596959705971597259735974597559765977597859795980598159825983598459855986598759885989599059915992599359945995599659975998599960006001600260036004600560066007600860096010601160126013601460156016601760186019602060216022602360246025602660276028602960306031603260336034603560366037603860396040604160426043604460456046604760486049605060516052605360546055605660576058605960606061606260636064606560666067606860696070607160726073607460756076607760786079608060816082608360846085608660876088608960906091609260936094609560966097609860996100610161026103610461056106610761086109611061116112611361146115611661176118 
  1. <!DOCTYPE html>
    2. 

  2. <html lang="en">
    3. 

  3.   <head>
    4. 

  4.     <meta charset="utf-8" />
    5. 

  5.     <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    6. 

  6.     <title>FFmpeg documentation</title>
    7. 

  7.     <link rel="stylesheet" href="bootstrap.min.css" />
    8. 

  8.     <link rel="stylesheet" href="style.min.css" />
    9. 

  9. 

  10. <meta name="description" content="FFmpeg Codecs Documentation: ">
    11. 

  11. <meta name="keywords" content="FFmpeg documentation : FFmpeg Codecs ">
    12. 

  12. <meta name="Generator" content="texi2html 5.0">
    13. 

  13. <!-- Created on June 8, 2020 by texi2html 5.0 -->
    14. 

  14. <!--
    15. 

  15. texi2html was written by: 
    16. 

  16.             Lionel Cons <Lionel.Cons@cern.ch> (original author)
    17. 

  17.             Karl Berry  <karl@freefriends.org>
    18. 

  18.             Olaf Bachmann <obachman@mathematik.uni-kl.de>
    19. 

  19.             and many others.
    20. 

  20. Maintained by: Many creative people.
    21. 

  21. Send bugs and suggestions to <texi2html-bug@nongnu.org>
    22. 

  22. 

  23. -->
    24. 

  24. <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    25. 

  25.   </head>
    26. 

  26.   <body>
    27. 

  27.     <div class="container">
    28. 

  28. 

  29. <h1 class="titlefont">FFmpeg Codecs Documentation</h1>
    30. 

  30. <hr>
    31. 

  31. <a name="SEC_Top"></a>
    32. 

  32. 

  33. <a name="SEC_Contents"></a>
    34. 

  34. <h1>Table of Contents</h1>
    35. 

  35. 

  36. <div class="contents">
    37. 

  37. 

  38. <ul class="no-bullet">
    39. 

  39.   <li><a name="toc-Description" href="#Description">1 Description</a></li>
    40. 

  40.   <li><a name="toc-Codec-Options" href="#Codec-Options">2 Codec Options</a></li>
    41. 

  41.   <li><a name="toc-Decoders" href="#Decoders">3 Decoders</a></li>
    42. 

  42.   <li><a name="toc-Video-Decoders" href="#Video-Decoders">4 Video Decoders</a>
    43. 

  43.   <ul class="no-bullet">
    44. 

  44.     <li><a name="toc-rawvideo" href="#rawvideo">4.1 rawvideo</a>
    45. 

  45.     <ul class="no-bullet">
    46. 

  46.       <li><a name="toc-Options-1" href="#Options-1">4.1.1 Options</a></li>
    47. 

  47.     </ul></li>
    48. 

  48.     <li><a name="toc-libdav1d" href="#libdav1d">4.2 libdav1d</a>
    49. 

  49.     <ul class="no-bullet">
    50. 

  50.       <li><a name="toc-Options-8" href="#Options-8">4.2.1 Options</a></li>
    51. 

  51.     </ul></li>
    52. 

  52.     <li><a name="toc-libdavs2" href="#libdavs2">4.3 libdavs2</a></li>
    53. 

  53.   </ul></li>
    54. 

  54.   <li><a name="toc-Audio-Decoders" href="#Audio-Decoders">5 Audio Decoders</a>
    55. 

  55.   <ul class="no-bullet">
    56. 

  56.     <li><a name="toc-ac3" href="#ac3">5.1 ac3</a>
    57. 

  57.     <ul class="no-bullet">
    58. 

  58.       <li><a name="toc-AC_002d3-Decoder-Options" href="#AC_002d3-Decoder-Options">5.1.1 AC-3 Decoder Options</a></li>
    59. 

  59.     </ul></li>
    60. 

  60.     <li><a name="toc-flac-1" href="#flac-1">5.2 flac</a>
    61. 

  61.     <ul class="no-bullet">
    62. 

  62.       <li><a name="toc-FLAC-Decoder-options" href="#FLAC-Decoder-options">5.2.1 FLAC Decoder options</a></li>
    63. 

  63.     </ul></li>
    64. 

  64.     <li><a name="toc-ffwavesynth" href="#ffwavesynth">5.3 ffwavesynth</a></li>
    65. 

  65.     <li><a name="toc-libcelt" href="#libcelt">5.4 libcelt</a></li>
    66. 

  66.     <li><a name="toc-libgsm" href="#libgsm">5.5 libgsm</a></li>
    67. 

  67.     <li><a name="toc-libilbc" href="#libilbc">5.6 libilbc</a>
    68. 

  68.     <ul class="no-bullet">
    69. 

  69.       <li><a name="toc-Options-33" href="#Options-33">5.6.1 Options</a></li>
    70. 

  70.     </ul></li>
    71. 

  71.     <li><a name="toc-libopencore_002damrnb" href="#libopencore_002damrnb">5.7 libopencore-amrnb</a></li>
    72. 

  72.     <li><a name="toc-libopencore_002damrwb" href="#libopencore_002damrwb">5.8 libopencore-amrwb</a></li>
    73. 

  73.     <li><a name="toc-libopus-1" href="#libopus-1">5.9 libopus</a></li>
    74. 

  74.   </ul></li>
    75. 

  75.   <li><a name="toc-Subtitles-Decoders" href="#Subtitles-Decoders">6 Subtitles Decoders</a>
    76. 

  76.   <ul class="no-bullet">
    77. 

  77.     <li><a name="toc-libaribb24" href="#libaribb24">6.1 libaribb24</a>
    78. 

  78.     <ul class="no-bullet">
    79. 

  79.       <li><a name="toc-libaribb24-Decoder-Options" href="#libaribb24-Decoder-Options">6.1.1 libaribb24 Decoder Options</a></li>
    80. 

  80.     </ul></li>
    81. 

  81.     <li><a name="toc-dvbsub" href="#dvbsub">6.2 dvbsub</a>
    82. 

  82.     <ul class="no-bullet">
    83. 

  83.       <li><a name="toc-Options-10" href="#Options-10">6.2.1 Options</a></li>
    84. 

  84.     </ul></li>
    85. 

  85.     <li><a name="toc-dvdsub" href="#dvdsub">6.3 dvdsub</a>
    86. 

  86.     <ul class="no-bullet">
    87. 

  87.       <li><a name="toc-Options-3" href="#Options-3">6.3.1 Options</a></li>
    88. 

  88.     </ul></li>
    89. 

  89.     <li><a name="toc-libzvbi_002dteletext" href="#libzvbi_002dteletext">6.4 libzvbi-teletext</a>
    90. 

  90.     <ul class="no-bullet">
    91. 

  91.       <li><a name="toc-Options-29" href="#Options-29">6.4.1 Options</a></li>
    92. 

  92.     </ul>
    93. 

  93. </li>
    94. 

  94.   </ul></li>
    95. 

  95.   <li><a name="toc-Encoders" href="#Encoders">7 Encoders</a></li>
    96. 

  96.   <li><a name="toc-Audio-Encoders" href="#Audio-Encoders">8 Audio Encoders</a>
    97. 

  97.   <ul class="no-bullet">
    98. 

  98.     <li><a name="toc-aac" href="#aac">8.1 aac</a>
    99. 

  99.     <ul class="no-bullet">
    100. 

  100.       <li><a name="toc-Options-12" href="#Options-12">8.1.1 Options</a></li>
    101. 

  101.     </ul></li>
    102. 

  102.     <li><a name="toc-ac3-and-ac3_005ffixed" href="#ac3-and-ac3_005ffixed">8.2 ac3 and ac3_fixed</a>
    103. 

  103.     <ul class="no-bullet">
    104. 

  104.       <li><a name="toc-AC_002d3-Metadata" href="#AC_002d3-Metadata">8.2.1 AC-3 Metadata</a>
    105. 

  105.       <ul class="no-bullet">
    106. 

  106.         <li><a name="toc-Metadata-Control-Options" href="#Metadata-Control-Options">8.2.1.1 Metadata Control Options</a></li>
    107. 

  107.         <li><a name="toc-Downmix-Levels" href="#Downmix-Levels">8.2.1.2 Downmix Levels</a></li>
    108. 

  108.         <li><a name="toc-Audio-Production-Information" href="#Audio-Production-Information">8.2.1.3 Audio Production Information</a></li>
    109. 

  109.         <li><a name="toc-Other-Metadata-Options" href="#Other-Metadata-Options">8.2.1.4 Other Metadata Options</a></li>
    110. 

  110.       </ul></li>
    111. 

  111.       <li><a name="toc-Extended-Bitstream-Information" href="#Extended-Bitstream-Information">8.2.2 Extended Bitstream Information</a>
    112. 

  112.       <ul class="no-bullet">
    113. 

  113.         <li><a name="toc-Extended-Bitstream-Information-_002d-Part-1" href="#Extended-Bitstream-Information-_002d-Part-1">8.2.2.1 Extended Bitstream Information - Part 1</a></li>
    114. 

  114.         <li><a name="toc-Extended-Bitstream-Information-_002d-Part-2" href="#Extended-Bitstream-Information-_002d-Part-2">8.2.2.2 Extended Bitstream Information - Part 2</a></li>
    115. 

  115.       </ul></li>
    116. 

  116.       <li><a name="toc-Other-AC_002d3-Encoding-Options" href="#Other-AC_002d3-Encoding-Options">8.2.3 Other AC-3 Encoding Options</a></li>
    117. 

  117.       <li><a name="toc-Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options" href="#Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options">8.2.4 Floating-Point-Only AC-3 Encoding Options</a></li>
    118. 

  118.     </ul></li>
    119. 

  119.     <li><a name="toc-flac-2" href="#flac-2">8.3 flac</a>
    120. 

  120.     <ul class="no-bullet">
    121. 

  121.       <li><a name="toc-Options-5" href="#Options-5">8.3.1 Options</a></li>
    122. 

  122.     </ul></li>
    123. 

  123.     <li><a name="toc-opus" href="#opus">8.4 opus</a>
    124. 

  124.     <ul class="no-bullet">
    125. 

  125.       <li><a name="toc-Options-32" href="#Options-32">8.4.1 Options</a></li>
    126. 

  126.     </ul></li>
    127. 

  127.     <li><a name="toc-libfdk_005faac" href="#libfdk_005faac">8.5 libfdk_aac</a>
    128. 

  128.     <ul class="no-bullet">
    129. 

  129.       <li><a name="toc-Options-19" href="#Options-19">8.5.1 Options</a></li>
    130. 

  130.       <li><a name="toc-Examples" href="#Examples">8.5.2 Examples</a></li>
    131. 

  131.     </ul></li>
    132. 

  132.     <li><a name="toc-libmp3lame-1" href="#libmp3lame-1">8.6 libmp3lame</a>
    133. 

  133.     <ul class="no-bullet">
    134. 

  134.       <li><a name="toc-Options-11" href="#Options-11">8.6.1 Options</a></li>
    135. 

  135.     </ul></li>
    136. 

  136.     <li><a name="toc-libopencore_002damrnb-1" href="#libopencore_002damrnb-1">8.7 libopencore-amrnb</a>
    137. 

  137.     <ul class="no-bullet">
    138. 

  138.       <li><a name="toc-Options-6" href="#Options-6">8.7.1 Options</a></li>
    139. 

  139.     </ul></li>
    140. 

  140.     <li><a name="toc-libopus" href="#libopus">8.8 libopus</a>
    141. 

  141.     <ul class="no-bullet">
    142. 

  142.       <li><a name="toc-Option-Mapping" href="#Option-Mapping">8.8.1 Option Mapping</a></li>
    143. 

  143.     </ul></li>
    144. 

  144.     <li><a name="toc-libshine-1" href="#libshine-1">8.9 libshine</a>
    145. 

  145.     <ul class="no-bullet">
    146. 

  146.       <li><a name="toc-Options-16" href="#Options-16">8.9.1 Options</a></li>
    147. 

  147.     </ul></li>
    148. 

  148.     <li><a name="toc-libtwolame" href="#libtwolame">8.10 libtwolame</a>
    149. 

  149.     <ul class="no-bullet">
    150. 

  150.       <li><a name="toc-Options-31" href="#Options-31">8.10.1 Options</a></li>
    151. 

  151.     </ul></li>
    152. 

  152.     <li><a name="toc-libvo_002damrwbenc" href="#libvo_002damrwbenc">8.11 libvo-amrwbenc</a>
    153. 

  153.     <ul class="no-bullet">
    154. 

  154.       <li><a name="toc-Options" href="#Options">8.11.1 Options</a></li>
    155. 

  155.     </ul></li>
    156. 

  156.     <li><a name="toc-libvorbis" href="#libvorbis">8.12 libvorbis</a>
    157. 

  157.     <ul class="no-bullet">
    158. 

  158.       <li><a name="toc-Options-7" href="#Options-7">8.12.1 Options</a></li>
    159. 

  159.     </ul></li>
    160. 

  160.     <li><a name="toc-libwavpack-1" href="#libwavpack-1">8.13 libwavpack</a>
    161. 

  161.     <ul class="no-bullet">
    162. 

  162.       <li><a name="toc-Options-35" href="#Options-35">8.13.1 Options</a></li>
    163. 

  163.     </ul></li>
    164. 

  164.     <li><a name="toc-mjpeg" href="#mjpeg">8.14 mjpeg</a>
    165. 

  165.     <ul class="no-bullet">
    166. 

  166.       <li><a name="toc-Options-22" href="#Options-22">8.14.1 Options</a></li>
    167. 

  167.     </ul></li>
    168. 

  168.     <li><a name="toc-wavpack" href="#wavpack">8.15 wavpack</a>
    169. 

  169.     <ul class="no-bullet">
    170. 

  170.       <li><a name="toc-Options-24" href="#Options-24">8.15.1 Options</a>
    171. 

  171.       <ul class="no-bullet">
    172. 

  172.         <li><a name="toc-Shared-options" href="#Shared-options">8.15.1.1 Shared options</a></li>
    173. 

  173.         <li><a name="toc-Private-options" href="#Private-options">8.15.1.2 Private options</a></li>
    174. 

  174.       </ul>
    175. 

  175. </li>
    176. 

  176.     </ul>
    177. 

  177. </li>
    178. 

  178.   </ul></li>
    179. 

  179.   <li><a name="toc-Video-Encoders" href="#Video-Encoders">9 Video Encoders</a>
    180. 

  180.   <ul class="no-bullet">
    181. 

  181.     <li><a name="toc-Hap" href="#Hap">9.1 Hap</a>
    182. 

  182.     <ul class="no-bullet">
    183. 

  183.       <li><a name="toc-Options-26" href="#Options-26">9.1.1 Options</a></li>
    184. 

  184.     </ul></li>
    185. 

  185.     <li><a name="toc-jpeg2000" href="#jpeg2000">9.2 jpeg2000</a>
    186. 

  186.     <ul class="no-bullet">
    187. 

  187.       <li><a name="toc-Options-17" href="#Options-17">9.2.1 Options</a></li>
    188. 

  188.     </ul></li>
    189. 

  189.     <li><a name="toc-librav1e" href="#librav1e">9.3 librav1e</a>
    190. 

  190.     <ul class="no-bullet">
    191. 

  191.       <li><a name="toc-Options-14" href="#Options-14">9.3.1 Options</a></li>
    192. 

  192.     </ul></li>
    193. 

  193.     <li><a name="toc-libaom_002dav1" href="#libaom_002dav1">9.4 libaom-av1</a>
    194. 

  194.     <ul class="no-bullet">
    195. 

  195.       <li><a name="toc-Options-4" href="#Options-4">9.4.1 Options</a></li>
    196. 

  196.     </ul></li>
    197. 

  197.     <li><a name="toc-libkvazaar" href="#libkvazaar">9.5 libkvazaar</a>
    198. 

  198.     <ul class="no-bullet">
    199. 

  199.       <li><a name="toc-Options-20" href="#Options-20">9.5.1 Options</a></li>
    200. 

  200.     </ul></li>
    201. 

  201.     <li><a name="toc-libopenh264" href="#libopenh264">9.6 libopenh264</a>
    202. 

  202.     <ul class="no-bullet">
    203. 

  203.       <li><a name="toc-Options-34" href="#Options-34">9.6.1 Options</a></li>
    204. 

  204.     </ul></li>
    205. 

  205.     <li><a name="toc-libtheora" href="#libtheora">9.7 libtheora</a>
    206. 

  206.     <ul class="no-bullet">
    207. 

  207.       <li><a name="toc-Options-30" href="#Options-30">9.7.1 Options</a></li>
    208. 

  208.       <li><a name="toc-Examples-1" href="#Examples-1">9.7.2 Examples</a></li>
    209. 

  209.     </ul></li>
    210. 

  210.     <li><a name="toc-libvpx" href="#libvpx">9.8 libvpx</a>
    211. 

  211.     <ul class="no-bullet">
    212. 

  212.       <li><a name="toc-Options-9" href="#Options-9">9.8.1 Options</a></li>
    213. 

  213.     </ul></li>
    214. 

  214.     <li><a name="toc-libwebp" href="#libwebp">9.9 libwebp</a>
    215. 

  215.     <ul class="no-bullet">
    216. 

  216.       <li><a name="toc-Pixel-Format" href="#Pixel-Format">9.9.1 Pixel Format</a></li>
    217. 

  217.       <li><a name="toc-Options-28" href="#Options-28">9.9.2 Options</a></li>
    218. 

  218.     </ul></li>
    219. 

  219.     <li><a name="toc-libx264_002c-libx264rgb" href="#libx264_002c-libx264rgb">9.10 libx264, libx264rgb</a>
    220. 

  220.     <ul class="no-bullet">
    221. 

  221.       <li><a name="toc-Supported-Pixel-Formats" href="#Supported-Pixel-Formats">9.10.1 Supported Pixel Formats</a></li>
    222. 

  222.       <li><a name="toc-Options-23" href="#Options-23">9.10.2 Options</a></li>
    223. 

  223.     </ul></li>
    224. 

  224.     <li><a name="toc-libx265" href="#libx265">9.11 libx265</a>
    225. 

  225.     <ul class="no-bullet">
    226. 

  226.       <li><a name="toc-Options-2" href="#Options-2">9.11.1 Options</a></li>
    227. 

  227.     </ul></li>
    228. 

  228.     <li><a name="toc-libxavs2" href="#libxavs2">9.12 libxavs2</a>
    229. 

  229.     <ul class="no-bullet">
    230. 

  230.       <li><a name="toc-Options-27" href="#Options-27">9.12.1 Options</a></li>
    231. 

  231.     </ul></li>
    232. 

  232.     <li><a name="toc-libxvid" href="#libxvid">9.13 libxvid</a>
    233. 

  233.     <ul class="no-bullet">
    234. 

  234.       <li><a name="toc-Options-25" href="#Options-25">9.13.1 Options</a></li>
    235. 

  235.     </ul></li>
    236. 

  236.     <li><a name="toc-MediaFoundation" href="#MediaFoundation">9.14 MediaFoundation</a></li>
    237. 

  237.     <li><a name="toc-mpeg2" href="#mpeg2">9.15 mpeg2</a>
    238. 

  238.     <ul class="no-bullet">
    239. 

  239.       <li><a name="toc-Options-13" href="#Options-13">9.15.1 Options</a></li>
    240. 

  240.     </ul></li>
    241. 

  241.     <li><a name="toc-png" href="#png">9.16 png</a>
    242. 

  242.     <ul class="no-bullet">
    243. 

  243.       <li><a name="toc-Private-options-1" href="#Private-options-1">9.16.1 Private options</a></li>
    244. 

  244.     </ul></li>
    245. 

  245.     <li><a name="toc-ProRes" href="#ProRes">9.17 ProRes</a>
    246. 

  246.     <ul class="no-bullet">
    247. 

  247.       <li><a name="toc-Private-Options-for-prores_002dks" href="#Private-Options-for-prores_002dks">9.17.1 Private Options for prores-ks</a></li>
    248. 

  248.       <li><a name="toc-Speed-considerations" href="#Speed-considerations">9.17.2 Speed considerations</a></li>
    249. 

  249.     </ul></li>
    250. 

  250.     <li><a name="toc-QSV-encoders" href="#QSV-encoders">9.18 QSV encoders</a></li>
    251. 

  251.     <li><a name="toc-snow" href="#snow">9.19 snow</a>
    252. 

  252.     <ul class="no-bullet">
    253. 

  253.       <li><a name="toc-Options-15" href="#Options-15">9.19.1 Options</a></li>
    254. 

  254.     </ul></li>
    255. 

  255.     <li><a name="toc-VAAPI-encoders" href="#VAAPI-encoders">9.20 VAAPI encoders</a></li>
    256. 

  256.     <li><a name="toc-vc2" href="#vc2">9.21 vc2</a>
    257. 

  257.     <ul class="no-bullet">
    258. 

  258.       <li><a name="toc-Options-18" href="#Options-18">9.21.1 Options</a></li>
    259. 

  259.     </ul>
    260. 

  260. </li>
    261. 

  261.   </ul></li>
    262. 

  262.   <li><a name="toc-Subtitles-Encoders" href="#Subtitles-Encoders">10 Subtitles Encoders</a>
    263. 

  263.   <ul class="no-bullet">
    264. 

  264.     <li><a name="toc-dvdsub-1" href="#dvdsub-1">10.1 dvdsub</a>
    265. 

  265.     <ul class="no-bullet">
    266. 

  266.       <li><a name="toc-Options-21" href="#Options-21">10.1.1 Options</a></li>
    267. 

  267.     </ul>
    268. 

  268. </li>
    269. 

  269.   </ul></li>
    270. 

  270.   <li><a name="toc-See-Also" href="#See-Also">11 See Also</a></li>
    271. 

  271.   <li><a name="toc-Authors" href="#Authors">12 Authors</a></li>
    272. 

  272. </ul>
    273. 

  273. </div>
    274. 

  274. 

  275. 

  276. <hr size="6">
    277. 

  277. <a name="Description"></a>
    278. 

  278. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Description">1 Description</a></h1>
    279. 

  279. 

  280. <p>This document describes the codecs (decoders and encoders) provided by
    281. 

  281. the libavcodec library.
    282. 

  282. </p>
    283. 

  283. 

  284. <p><a name="codec_002doptions"></a>
    285. 

  285. </p><a name="Codec-Options"></a>
    286. 

  286. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Codec-Options">2 Codec Options</a></h1>
    287. 

  287. 

  288. <p>libavcodec provides some generic global options, which can be set on
    289. 

  289. all the encoders and decoders. In addition each codec may support
    290. 

  290. so-called private options, which are specific for a given codec.
    291. 

  291. </p>
    292. 

  292. <p>Sometimes, a global option may only affect a specific kind of codec,
    293. 

  293. and may be nonsensical or ignored by another, so you need to be aware
    294. 

  294. of the meaning of the specified options. Also some options are
    295. 

  295. meant only for decoding or encoding.
    296. 

  296. </p>
    297. 

  297. <p>Options may be set by specifying -<var>option</var> <var>value</var> in the
    298. 

  298. FFmpeg tools, or by setting the value explicitly in the
    299. 

  299. <code>AVCodecContext</code> options or using the &lsquo;<tt>libavutil/opt.h</tt>&rsquo; API
    300. 

  300. for programmatic use.
    301. 

  301. </p>
    302. 

  302. <p>The list of supported options follow:
    303. 

  303. </p>
    304. 

  304. <dl compact="compact">
    305. 

  305. <dt>&lsquo;<samp>b <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
    306. 

  306. <dd><p>Set bitrate in bits/s. Default value is 200K.
    307. 

  307. </p>
    308. 

  308. </dd>
    309. 

  309. <dt>&lsquo;<samp>ab <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
    310. 

  310. <dd><p>Set audio bitrate (in bits/s). Default value is 128K.
    311. 

  311. </p>
    312. 

  312. </dd>
    313. 

  313. <dt>&lsquo;<samp>bt <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    314. 

  314. <dd><p>Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate
    315. 

  315. tolerance specifies how far ratecontrol is willing to deviate from the
    316. 

  316. target average bitrate value. This is not related to min/max
    317. 

  317. bitrate. Lowering tolerance too much has an adverse effect on quality.
    318. 

  318. </p>
    319. 

  319. </dd>
    320. 

  320. <dt>&lsquo;<samp>flags <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp>&rsquo;</dt>
    321. 

  321. <dd><p>Set generic flags.
    322. 

  322. </p>
    323. 

  323. <p>Possible values:
    324. 

  324. </p><dl compact="compact">
    325. 

  325. <dt>&lsquo;<samp>mv4</samp>&rsquo;</dt>
    326. 

  326. <dd><p>Use four motion vector by macroblock (mpeg4).
    327. 

  327. </p></dd>
    328. 

  328. <dt>&lsquo;<samp>qpel</samp>&rsquo;</dt>
    329. 

  329. <dd><p>Use 1/4 pel motion compensation.
    330. 

  330. </p></dd>
    331. 

  331. <dt>&lsquo;<samp>loop</samp>&rsquo;</dt>
    332. 

  332. <dd><p>Use loop filter.
    333. 

  333. </p></dd>
    334. 

  334. <dt>&lsquo;<samp>qscale</samp>&rsquo;</dt>
    335. 

  335. <dd><p>Use fixed qscale.
    336. 

  336. </p></dd>
    337. 

  337. <dt>&lsquo;<samp>pass1</samp>&rsquo;</dt>
    338. 

  338. <dd><p>Use internal 2pass ratecontrol in first pass mode.
    339. 

  339. </p></dd>
    340. 

  340. <dt>&lsquo;<samp>pass2</samp>&rsquo;</dt>
    341. 

  341. <dd><p>Use internal 2pass ratecontrol in second pass mode.
    342. 

  342. </p></dd>
    343. 

  343. <dt>&lsquo;<samp>gray</samp>&rsquo;</dt>
    344. 

  344. <dd><p>Only decode/encode grayscale.
    345. 

  345. </p></dd>
    346. 

  346. <dt>&lsquo;<samp>emu_edge</samp>&rsquo;</dt>
    347. 

  347. <dd><p>Do not draw edges.
    348. 

  348. </p></dd>
    349. 

  349. <dt>&lsquo;<samp>psnr</samp>&rsquo;</dt>
    350. 

  350. <dd><p>Set error[?] variables during encoding.
    351. 

  351. </p></dd>
    352. 

  352. <dt>&lsquo;<samp>truncated</samp>&rsquo;</dt>
    353. 

  353. <dd><p>Input bitstream might be randomly truncated.
    354. 

  354. </p></dd>
    355. 

  355. <dt>&lsquo;<samp>drop_changed</samp>&rsquo;</dt>
    356. 

  356. <dd><p>Don&rsquo;t output frames whose parameters differ from first decoded frame in stream.
    357. 

  357. Error AVERROR_INPUT_CHANGED is returned when a frame is dropped.
    358. 

  358. </p>
    359. 

  359. </dd>
    360. 

  360. <dt>&lsquo;<samp>ildct</samp>&rsquo;</dt>
    361. 

  361. <dd><p>Use interlaced DCT.
    362. 

  362. </p></dd>
    363. 

  363. <dt>&lsquo;<samp>low_delay</samp>&rsquo;</dt>
    364. 

  364. <dd><p>Force low delay.
    365. 

  365. </p></dd>
    366. 

  366. <dt>&lsquo;<samp>global_header</samp>&rsquo;</dt>
    367. 

  367. <dd><p>Place global headers in extradata instead of every keyframe.
    368. 

  368. </p></dd>
    369. 

  369. <dt>&lsquo;<samp>bitexact</samp>&rsquo;</dt>
    370. 

  370. <dd><p>Only write platform-, build- and time-independent data. (except (I)DCT).
    371. 

  371. This ensures that file and data checksums are reproducible and match between
    372. 

  372. platforms. Its primary use is for regression testing.
    373. 

  373. </p></dd>
    374. 

  374. <dt>&lsquo;<samp>aic</samp>&rsquo;</dt>
    375. 

  375. <dd><p>Apply H263 advanced intra coding / mpeg4 ac prediction.
    376. 

  376. </p></dd>
    377. 

  377. <dt>&lsquo;<samp>cbp</samp>&rsquo;</dt>
    378. 

  378. <dd><p>Deprecated, use mpegvideo private options instead.
    379. 

  379. </p></dd>
    380. 

  380. <dt>&lsquo;<samp>qprd</samp>&rsquo;</dt>
    381. 

  381. <dd><p>Deprecated, use mpegvideo private options instead.
    382. 

  382. </p></dd>
    383. 

  383. <dt>&lsquo;<samp>ilme</samp>&rsquo;</dt>
    384. 

  384. <dd><p>Apply interlaced motion estimation.
    385. 

  385. </p></dd>
    386. 

  386. <dt>&lsquo;<samp>cgop</samp>&rsquo;</dt>
    387. 

  387. <dd><p>Use closed gop.
    388. 

  388. </p></dd>
    389. 

  389. <dt>&lsquo;<samp>output_corrupt</samp>&rsquo;</dt>
    390. 

  390. <dd><p>Output even potentially corrupted frames.
    391. 

  391. </p></dd>
    392. 

  392. </dl>
    393. 

  393. 

  394. </dd>
    395. 

  395. <dt>&lsquo;<samp>me_method <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    396. 

  396. <dd><p>Set motion estimation method.
    397. 

  397. </p>
    398. 

  398. <p>Possible values:
    399. 

  399. </p><dl compact="compact">
    400. 

  400. <dt>&lsquo;<samp>zero</samp>&rsquo;</dt>
    401. 

  401. <dd><p>zero motion estimation (fastest)
    402. 

  402. </p></dd>
    403. 

  403. <dt>&lsquo;<samp>full</samp>&rsquo;</dt>
    404. 

  404. <dd><p>full motion estimation (slowest)
    405. 

  405. </p></dd>
    406. 

  406. <dt>&lsquo;<samp>epzs</samp>&rsquo;</dt>
    407. 

  407. <dd><p>EPZS motion estimation (default)
    408. 

  408. </p></dd>
    409. 

  409. <dt>&lsquo;<samp>esa</samp>&rsquo;</dt>
    410. 

  410. <dd><p>esa motion estimation (alias for full)
    411. 

  411. </p></dd>
    412. 

  412. <dt>&lsquo;<samp>tesa</samp>&rsquo;</dt>
    413. 

  413. <dd><p>tesa motion estimation
    414. 

  414. </p></dd>
    415. 

  415. <dt>&lsquo;<samp>dia</samp>&rsquo;</dt>
    416. 

  416. <dd><p>dia motion estimation (alias for epzs)
    417. 

  417. </p></dd>
    418. 

  418. <dt>&lsquo;<samp>log</samp>&rsquo;</dt>
    419. 

  419. <dd><p>log motion estimation
    420. 

  420. </p></dd>
    421. 

  421. <dt>&lsquo;<samp>phods</samp>&rsquo;</dt>
    422. 

  422. <dd><p>phods motion estimation
    423. 

  423. </p></dd>
    424. 

  424. <dt>&lsquo;<samp>x1</samp>&rsquo;</dt>
    425. 

  425. <dd><p>X1 motion estimation
    426. 

  426. </p></dd>
    427. 

  427. <dt>&lsquo;<samp>hex</samp>&rsquo;</dt>
    428. 

  428. <dd><p>hex motion estimation
    429. 

  429. </p></dd>
    430. 

  430. <dt>&lsquo;<samp>umh</samp>&rsquo;</dt>
    431. 

  431. <dd><p>umh motion estimation
    432. 

  432. </p></dd>
    433. 

  433. <dt>&lsquo;<samp>iter</samp>&rsquo;</dt>
    434. 

  434. <dd><p>iter motion estimation
    435. 

  435. </p></dd>
    436. 

  436. </dl>
    437. 

  437. 

  438. </dd>
    439. 

  439. <dt>&lsquo;<samp>extradata_size <var>integer</var></samp>&rsquo;</dt>
    440. 

  440. <dd><p>Set extradata size.
    441. 

  441. </p>
    442. 

  442. </dd>
    443. 

  443. <dt>&lsquo;<samp>time_base <var>rational number</var></samp>&rsquo;</dt>
    444. 

  444. <dd><p>Set codec time base.
    445. 

  445. </p>
    446. 

  446. <p>It is the fundamental unit of time (in seconds) in terms of which
    447. 

  447. frame timestamps are represented. For fixed-fps content, timebase
    448. 

  448. should be <code>1 / frame_rate</code> and timestamp increments should be
    449. 

  449. identically 1.
    450. 

  450. </p>
    451. 

  451. </dd>
    452. 

  452. <dt>&lsquo;<samp>g <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    453. 

  453. <dd><p>Set the group of picture (GOP) size. Default value is 12.
    454. 

  454. </p>
    455. 

  455. </dd>
    456. 

  456. <dt>&lsquo;<samp>ar <var>integer</var> (<em>decoding/encoding,audio</em>)</samp>&rsquo;</dt>
    457. 

  457. <dd><p>Set audio sampling rate (in Hz).
    458. 

  458. </p>
    459. 

  459. </dd>
    460. 

  460. <dt>&lsquo;<samp>ac <var>integer</var> (<em>decoding/encoding,audio</em>)</samp>&rsquo;</dt>
    461. 

  461. <dd><p>Set number of audio channels.
    462. 

  462. </p>
    463. 

  463. </dd>
    464. 

  464. <dt>&lsquo;<samp>cutoff <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
    465. 

  465. <dd><p>Set cutoff bandwidth. (Supported only by selected encoders, see
    466. 

  466. their respective documentation sections.)
    467. 

  467. </p>
    468. 

  468. </dd>
    469. 

  469. <dt>&lsquo;<samp>frame_size <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
    470. 

  470. <dd><p>Set audio frame size.
    471. 

  471. </p>
    472. 

  472. <p>Each submitted frame except the last must contain exactly frame_size
    473. 

  473. samples per channel. May be 0 when the codec has
    474. 

  474. CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame size is not
    475. 

  475. restricted. It is set by some decoders to indicate constant frame
    476. 

  476. size.
    477. 

  477. </p>
    478. 

  478. </dd>
    479. 

  479. <dt>&lsquo;<samp>frame_number <var>integer</var></samp>&rsquo;</dt>
    480. 

  480. <dd><p>Set the frame number.
    481. 

  481. </p>
    482. 

  482. </dd>
    483. 

  483. <dt>&lsquo;<samp>delay <var>integer</var></samp>&rsquo;</dt>
    484. 

  484. <dt>&lsquo;<samp>qcomp <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    485. 

  485. <dd><p>Set video quantizer scale compression (VBR). It is used as a constant
    486. 

  486. in the ratecontrol equation. Recommended range for default rc_eq:
    487. 

  487. 0.0-1.0.
    488. 

  488. </p>
    489. 

  489. </dd>
    490. 

  490. <dt>&lsquo;<samp>qblur <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    491. 

  491. <dd><p>Set video quantizer scale blur (VBR).
    492. 

  492. </p>
    493. 

  493. </dd>
    494. 

  494. <dt>&lsquo;<samp>qmin <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    495. 

  495. <dd><p>Set min video quantizer scale (VBR). Must be included between -1 and
    496. 

  496. 69, default value is 2.
    497. 

  497. </p>
    498. 

  498. </dd>
    499. 

  499. <dt>&lsquo;<samp>qmax <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    500. 

  500. <dd><p>Set max video quantizer scale (VBR). Must be included between -1 and
    501. 

  501. 1024, default value is 31.
    502. 

  502. </p>
    503. 

  503. </dd>
    504. 

  504. <dt>&lsquo;<samp>qdiff <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    505. 

  505. <dd><p>Set max difference between the quantizer scale (VBR).
    506. 

  506. </p>
    507. 

  507. </dd>
    508. 

  508. <dt>&lsquo;<samp>bf <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    509. 

  509. <dd><p>Set max number of B frames between non-B-frames.
    510. 

  510. </p>
    511. 

  511. <p>Must be an integer between -1 and 16. 0 means that B-frames are
    512. 

  512. disabled. If a value of -1 is used, it will choose an automatic value
    513. 

  513. depending on the encoder.
    514. 

  514. </p>
    515. 

  515. <p>Default value is 0.
    516. 

  516. </p>
    517. 

  517. </dd>
    518. 

  518. <dt>&lsquo;<samp>b_qfactor <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    519. 

  519. <dd><p>Set qp factor between P and B frames.
    520. 

  520. </p>
    521. 

  521. </dd>
    522. 

  522. <dt>&lsquo;<samp>rc_strategy <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    523. 

  523. <dd><p>Set ratecontrol method.
    524. 

  524. </p>
    525. 

  525. </dd>
    526. 

  526. <dt>&lsquo;<samp>b_strategy <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    527. 

  527. <dd><p>Set strategy to choose between I/P/B-frames.
    528. 

  528. </p>
    529. 

  529. </dd>
    530. 

  530. <dt>&lsquo;<samp>ps <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    531. 

  531. <dd><p>Set RTP payload size in bytes.
    532. 

  532. </p>
    533. 

  533. </dd>
    534. 

  534. <dt>&lsquo;<samp>mv_bits <var>integer</var></samp>&rsquo;</dt>
    535. 

  535. <dt>&lsquo;<samp>header_bits <var>integer</var></samp>&rsquo;</dt>
    536. 

  536. <dt>&lsquo;<samp>i_tex_bits <var>integer</var></samp>&rsquo;</dt>
    537. 

  537. <dt>&lsquo;<samp>p_tex_bits <var>integer</var></samp>&rsquo;</dt>
    538. 

  538. <dt>&lsquo;<samp>i_count <var>integer</var></samp>&rsquo;</dt>
    539. 

  539. <dt>&lsquo;<samp>p_count <var>integer</var></samp>&rsquo;</dt>
    540. 

  540. <dt>&lsquo;<samp>skip_count <var>integer</var></samp>&rsquo;</dt>
    541. 

  541. <dt>&lsquo;<samp>misc_bits <var>integer</var></samp>&rsquo;</dt>
    542. 

  542. <dt>&lsquo;<samp>frame_bits <var>integer</var></samp>&rsquo;</dt>
    543. 

  543. <dt>&lsquo;<samp>codec_tag <var>integer</var></samp>&rsquo;</dt>
    544. 

  544. <dt>&lsquo;<samp>bug <var>flags</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
    545. 

  545. <dd><p>Workaround not auto detected encoder bugs.
    546. 

  546. </p>
    547. 

  547. <p>Possible values:
    548. 

  548. </p><dl compact="compact">
    549. 

  549. <dt>&lsquo;<samp>autodetect</samp>&rsquo;</dt>
    550. 

  550. <dt>&lsquo;<samp>old_msmpeg4</samp>&rsquo;</dt>
    551. 

  551. <dd><p>some old lavc generated msmpeg4v3 files (no autodetection)
    552. 

  552. </p></dd>
    553. 

  553. <dt>&lsquo;<samp>xvid_ilace</samp>&rsquo;</dt>
    554. 

  554. <dd><p>Xvid interlacing bug (autodetected if fourcc==XVIX)
    555. 

  555. </p></dd>
    556. 

  556. <dt>&lsquo;<samp>ump4</samp>&rsquo;</dt>
    557. 

  557. <dd><p>(autodetected if fourcc==UMP4)
    558. 

  558. </p></dd>
    559. 

  559. <dt>&lsquo;<samp>no_padding</samp>&rsquo;</dt>
    560. 

  560. <dd><p>padding bug (autodetected)
    561. 

  561. </p></dd>
    562. 

  562. <dt>&lsquo;<samp>amv</samp>&rsquo;</dt>
    563. 

  563. <dt>&lsquo;<samp>ac_vlc</samp>&rsquo;</dt>
    564. 

  564. <dd><p>illegal vlc bug (autodetected per fourcc)
    565. 

  565. </p></dd>
    566. 

  566. <dt>&lsquo;<samp>qpel_chroma</samp>&rsquo;</dt>
    567. 

  567. <dt>&lsquo;<samp>std_qpel</samp>&rsquo;</dt>
    568. 

  568. <dd><p>old standard qpel (autodetected per fourcc/version)
    569. 

  569. </p></dd>
    570. 

  570. <dt>&lsquo;<samp>qpel_chroma2</samp>&rsquo;</dt>
    571. 

  571. <dt>&lsquo;<samp>direct_blocksize</samp>&rsquo;</dt>
    572. 

  572. <dd><p>direct-qpel-blocksize bug (autodetected per fourcc/version)
    573. 

  573. </p></dd>
    574. 

  574. <dt>&lsquo;<samp>edge</samp>&rsquo;</dt>
    575. 

  575. <dd><p>edge padding bug (autodetected per fourcc/version)
    576. 

  576. </p></dd>
    577. 

  577. <dt>&lsquo;<samp>hpel_chroma</samp>&rsquo;</dt>
    578. 

  578. <dt>&lsquo;<samp>dc_clip</samp>&rsquo;</dt>
    579. 

  579. <dt>&lsquo;<samp>ms</samp>&rsquo;</dt>
    580. 

  580. <dd><p>Workaround various bugs in microsoft broken decoders.
    581. 

  581. </p></dd>
    582. 

  582. <dt>&lsquo;<samp>trunc</samp>&rsquo;</dt>
    583. 

  583. <dd><p>trancated frames
    584. 

  584. </p></dd>
    585. 

  585. </dl>
    586. 

  586. 

  587. </dd>
    588. 

  588. <dt>&lsquo;<samp>lelim <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    589. 

  589. <dd><p>Set single coefficient elimination threshold for luminance (negative
    590. 

  590. values also consider DC coefficient).
    591. 

  591. </p>
    592. 

  592. </dd>
    593. 

  593. <dt>&lsquo;<samp>celim <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    594. 

  594. <dd><p>Set single coefficient elimination threshold for chrominance (negative
    595. 

  595. values also consider dc coefficient)
    596. 

  596. </p>
    597. 

  597. </dd>
    598. 

  598. <dt>&lsquo;<samp>strict <var>integer</var> (<em>decoding/encoding,audio,video</em>)</samp>&rsquo;</dt>
    599. 

  599. <dd><p>Specify how strictly to follow the standards.
    600. 

  600. </p>
    601. 

  601. <p>Possible values:
    602. 

  602. </p><dl compact="compact">
    603. 

  603. <dt>&lsquo;<samp>very</samp>&rsquo;</dt>
    604. 

  604. <dd><p>strictly conform to an older more strict version of the spec or reference software
    605. 

  605. </p></dd>
    606. 

  606. <dt>&lsquo;<samp>strict</samp>&rsquo;</dt>
    607. 

  607. <dd><p>strictly conform to all the things in the spec no matter what consequences
    608. 

  608. </p></dd>
    609. 

  609. <dt>&lsquo;<samp>normal</samp>&rsquo;</dt>
    610. 

  610. <dt>&lsquo;<samp>unofficial</samp>&rsquo;</dt>
    611. 

  611. <dd><p>allow unofficial extensions
    612. 

  612. </p></dd>
    613. 

  613. <dt>&lsquo;<samp>experimental</samp>&rsquo;</dt>
    614. 

  614. <dd><p>allow non standardized experimental things, experimental
    615. 

  615. (unfinished/work in progress/not well tested) decoders and encoders.
    616. 

  616. Note: experimental decoders can pose a security risk, do not use this for
    617. 

  617. decoding untrusted input.
    618. 

  618. </p></dd>
    619. 

  619. </dl>
    620. 

  620. 

  621. </dd>
    622. 

  622. <dt>&lsquo;<samp>b_qoffset <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    623. 

  623. <dd><p>Set QP offset between P and B frames.
    624. 

  624. </p>
    625. 

  625. </dd>
    626. 

  626. <dt>&lsquo;<samp>err_detect <var>flags</var> (<em>decoding,audio,video</em>)</samp>&rsquo;</dt>
    627. 

  627. <dd><p>Set error detection flags.
    628. 

  628. </p>
    629. 

  629. <p>Possible values:
    630. 

  630. </p><dl compact="compact">
    631. 

  631. <dt>&lsquo;<samp>crccheck</samp>&rsquo;</dt>
    632. 

  632. <dd><p>verify embedded CRCs
    633. 

  633. </p></dd>
    634. 

  634. <dt>&lsquo;<samp>bitstream</samp>&rsquo;</dt>
    635. 

  635. <dd><p>detect bitstream specification deviations
    636. 

  636. </p></dd>
    637. 

  637. <dt>&lsquo;<samp>buffer</samp>&rsquo;</dt>
    638. 

  638. <dd><p>detect improper bitstream length
    639. 

  639. </p></dd>
    640. 

  640. <dt>&lsquo;<samp>explode</samp>&rsquo;</dt>
    641. 

  641. <dd><p>abort decoding on minor error detection
    642. 

  642. </p></dd>
    643. 

  643. <dt>&lsquo;<samp>ignore_err</samp>&rsquo;</dt>
    644. 

  644. <dd><p>ignore decoding errors, and continue decoding.
    645. 

  645. This is useful if you want to analyze the content of a video and thus want
    646. 

  646. everything to be decoded no matter what. This option will not result in a video
    647. 

  647. that is pleasing to watch in case of errors.
    648. 

  648. </p></dd>
    649. 

  649. <dt>&lsquo;<samp>careful</samp>&rsquo;</dt>
    650. 

  650. <dd><p>consider things that violate the spec and have not been seen in the wild as errors
    651. 

  651. </p></dd>
    652. 

  652. <dt>&lsquo;<samp>compliant</samp>&rsquo;</dt>
    653. 

  653. <dd><p>consider all spec non compliancies as errors
    654. 

  654. </p></dd>
    655. 

  655. <dt>&lsquo;<samp>aggressive</samp>&rsquo;</dt>
    656. 

  656. <dd><p>consider things that a sane encoder should not do as an error
    657. 

  657. </p></dd>
    658. 

  658. </dl>
    659. 

  659. 

  660. </dd>
    661. 

  661. <dt>&lsquo;<samp>has_b_frames <var>integer</var></samp>&rsquo;</dt>
    662. 

  662. <dt>&lsquo;<samp>block_align <var>integer</var></samp>&rsquo;</dt>
    663. 

  663. <dt>&lsquo;<samp>mpeg_quant <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    664. 

  664. <dd><p>Use MPEG quantizers instead of H.263.
    665. 

  665. </p>
    666. 

  666. </dd>
    667. 

  667. <dt>&lsquo;<samp>qsquish <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    668. 

  668. <dd><p>How to keep quantizer between qmin and qmax (0 = clip, 1 = use
    669. 

  669. differentiable function).
    670. 

  670. </p>
    671. 

  671. </dd>
    672. 

  672. <dt>&lsquo;<samp>rc_qmod_amp <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    673. 

  673. <dd><p>Set experimental quantizer modulation.
    674. 

  674. </p>
    675. 

  675. </dd>
    676. 

  676. <dt>&lsquo;<samp>rc_qmod_freq <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    677. 

  677. <dd><p>Set experimental quantizer modulation.
    678. 

  678. </p>
    679. 

  679. </dd>
    680. 

  680. <dt>&lsquo;<samp>rc_override_count <var>integer</var></samp>&rsquo;</dt>
    681. 

  681. <dt>&lsquo;<samp>rc_eq <var>string</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    682. 

  682. <dd><p>Set rate control equation. When computing the expression, besides the
    683. 

  683. standard functions defined in the section &rsquo;Expression Evaluation&rsquo;, the
    684. 

  684. following functions are available: bits2qp(bits), qp2bits(qp). Also
    685. 

  685. the following constants are available: iTex pTex tex mv fCode iCount
    686. 

  686. mcVar var isI isP isB avgQP qComp avgIITex avgPITex avgPPTex avgBPTex
    687. 

  687. avgTex.
    688. 

  688. </p>
    689. 

  689. </dd>
    690. 

  690. <dt>&lsquo;<samp>maxrate <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
    691. 

  691. <dd><p>Set max bitrate tolerance (in bits/s). Requires bufsize to be set.
    692. 

  692. </p>
    693. 

  693. </dd>
    694. 

  694. <dt>&lsquo;<samp>minrate <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
    695. 

  695. <dd><p>Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR
    696. 

  696. encode. It is of little use elsewise.
    697. 

  697. </p>
    698. 

  698. </dd>
    699. 

  699. <dt>&lsquo;<samp>bufsize <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
    700. 

  700. <dd><p>Set ratecontrol buffer size (in bits).
    701. 

  701. </p>
    702. 

  702. </dd>
    703. 

  703. <dt>&lsquo;<samp>rc_buf_aggressivity <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    704. 

  704. <dd><p>Currently useless.
    705. 

  705. </p>
    706. 

  706. </dd>
    707. 

  707. <dt>&lsquo;<samp>i_qfactor <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    708. 

  708. <dd><p>Set QP factor between P and I frames.
    709. 

  709. </p>
    710. 

  710. </dd>
    711. 

  711. <dt>&lsquo;<samp>i_qoffset <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    712. 

  712. <dd><p>Set QP offset between P and I frames.
    713. 

  713. </p>
    714. 

  714. </dd>
    715. 

  715. <dt>&lsquo;<samp>rc_init_cplx <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    716. 

  716. <dd><p>Set initial complexity for 1-pass encoding.
    717. 

  717. </p>
    718. 

  718. </dd>
    719. 

  719. <dt>&lsquo;<samp>dct <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    720. 

  720. <dd><p>Set DCT algorithm.
    721. 

  721. </p>
    722. 

  722. <p>Possible values:
    723. 

  723. </p><dl compact="compact">
    724. 

  724. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    725. 

  725. <dd><p>autoselect a good one (default)
    726. 

  726. </p></dd>
    727. 

  727. <dt>&lsquo;<samp>fastint</samp>&rsquo;</dt>
    728. 

  728. <dd><p>fast integer
    729. 

  729. </p></dd>
    730. 

  730. <dt>&lsquo;<samp>int</samp>&rsquo;</dt>
    731. 

  731. <dd><p>accurate integer
    732. 

  732. </p></dd>
    733. 

  733. <dt>&lsquo;<samp>mmx</samp>&rsquo;</dt>
    734. 

  734. <dt>&lsquo;<samp>altivec</samp>&rsquo;</dt>
    735. 

  735. <dt>&lsquo;<samp>faan</samp>&rsquo;</dt>
    736. 

  736. <dd><p>floating point AAN DCT
    737. 

  737. </p></dd>
    738. 

  738. </dl>
    739. 

  739. 

  740. </dd>
    741. 

  741. <dt>&lsquo;<samp>lumi_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    742. 

  742. <dd><p>Compress bright areas stronger than medium ones.
    743. 

  743. </p>
    744. 

  744. </dd>
    745. 

  745. <dt>&lsquo;<samp>tcplx_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    746. 

  746. <dd><p>Set temporal complexity masking.
    747. 

  747. </p>
    748. 

  748. </dd>
    749. 

  749. <dt>&lsquo;<samp>scplx_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    750. 

  750. <dd><p>Set spatial complexity masking.
    751. 

  751. </p>
    752. 

  752. </dd>
    753. 

  753. <dt>&lsquo;<samp>p_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    754. 

  754. <dd><p>Set inter masking.
    755. 

  755. </p>
    756. 

  756. </dd>
    757. 

  757. <dt>&lsquo;<samp>dark_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    758. 

  758. <dd><p>Compress dark areas stronger than medium ones.
    759. 

  759. </p>
    760. 

  760. </dd>
    761. 

  761. <dt>&lsquo;<samp>idct <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
    762. 

  762. <dd><p>Select IDCT implementation.
    763. 

  763. </p>
    764. 

  764. <p>Possible values:
    765. 

  765. </p><dl compact="compact">
    766. 

  766. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    767. 

  767. <dt>&lsquo;<samp>int</samp>&rsquo;</dt>
    768. 

  768. <dt>&lsquo;<samp>simple</samp>&rsquo;</dt>
    769. 

  769. <dt>&lsquo;<samp>simplemmx</samp>&rsquo;</dt>
    770. 

  770. <dt>&lsquo;<samp>simpleauto</samp>&rsquo;</dt>
    771. 

  771. <dd><p>Automatically pick a IDCT compatible with the simple one
    772. 

  772. </p>
    773. 

  773. </dd>
    774. 

  774. <dt>&lsquo;<samp>arm</samp>&rsquo;</dt>
    775. 

  775. <dt>&lsquo;<samp>altivec</samp>&rsquo;</dt>
    776. 

  776. <dt>&lsquo;<samp>sh4</samp>&rsquo;</dt>
    777. 

  777. <dt>&lsquo;<samp>simplearm</samp>&rsquo;</dt>
    778. 

  778. <dt>&lsquo;<samp>simplearmv5te</samp>&rsquo;</dt>
    779. 

  779. <dt>&lsquo;<samp>simplearmv6</samp>&rsquo;</dt>
    780. 

  780. <dt>&lsquo;<samp>simpleneon</samp>&rsquo;</dt>
    781. 

  781. <dt>&lsquo;<samp>simplealpha</samp>&rsquo;</dt>
    782. 

  782. <dt>&lsquo;<samp>ipp</samp>&rsquo;</dt>
    783. 

  783. <dt>&lsquo;<samp>xvidmmx</samp>&rsquo;</dt>
    784. 

  784. <dt>&lsquo;<samp>faani</samp>&rsquo;</dt>
    785. 

  785. <dd><p>floating point AAN IDCT
    786. 

  786. </p></dd>
    787. 

  787. </dl>
    788. 

  788. 

  789. </dd>
    790. 

  790. <dt>&lsquo;<samp>slice_count <var>integer</var></samp>&rsquo;</dt>
    791. 

  791. <dt>&lsquo;<samp>ec <var>flags</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
    792. 

  792. <dd><p>Set error concealment strategy.
    793. 

  793. </p>
    794. 

  794. <p>Possible values:
    795. 

  795. </p><dl compact="compact">
    796. 

  796. <dt>&lsquo;<samp>guess_mvs</samp>&rsquo;</dt>
    797. 

  797. <dd><p>iterative motion vector (MV) search (slow)
    798. 

  798. </p></dd>
    799. 

  799. <dt>&lsquo;<samp>deblock</samp>&rsquo;</dt>
    800. 

  800. <dd><p>use strong deblock filter for damaged MBs
    801. 

  801. </p></dd>
    802. 

  802. <dt>&lsquo;<samp>favor_inter</samp>&rsquo;</dt>
    803. 

  803. <dd><p>favor predicting from the previous frame instead of the current
    804. 

  804. </p></dd>
    805. 

  805. </dl>
    806. 

  806. 

  807. </dd>
    808. 

  808. <dt>&lsquo;<samp>bits_per_coded_sample <var>integer</var></samp>&rsquo;</dt>
    809. 

  809. <dt>&lsquo;<samp>pred <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    810. 

  810. <dd><p>Set prediction method.
    811. 

  811. </p>
    812. 

  812. <p>Possible values:
    813. 

  813. </p><dl compact="compact">
    814. 

  814. <dt>&lsquo;<samp>left</samp>&rsquo;</dt>
    815. 

  815. <dt>&lsquo;<samp>plane</samp>&rsquo;</dt>
    816. 

  816. <dt>&lsquo;<samp>median</samp>&rsquo;</dt>
    817. 

  817. </dl>
    818. 

  818. 

  819. </dd>
    820. 

  820. <dt>&lsquo;<samp>aspect <var>rational number</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    821. 

  821. <dd><p>Set sample aspect ratio.
    822. 

  822. </p>
    823. 

  823. </dd>
    824. 

  824. <dt>&lsquo;<samp>sar <var>rational number</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    825. 

  825. <dd><p>Set sample aspect ratio. Alias to <var>aspect</var>.
    826. 

  826. </p>
    827. 

  827. </dd>
    828. 

  828. <dt>&lsquo;<samp>debug <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp>&rsquo;</dt>
    829. 

  829. <dd><p>Print specific debug info.
    830. 

  830. </p>
    831. 

  831. <p>Possible values:
    832. 

  832. </p><dl compact="compact">
    833. 

  833. <dt>&lsquo;<samp>pict</samp>&rsquo;</dt>
    834. 

  834. <dd><p>picture info
    835. 

  835. </p></dd>
    836. 

  836. <dt>&lsquo;<samp>rc</samp>&rsquo;</dt>
    837. 

  837. <dd><p>rate control
    838. 

  838. </p></dd>
    839. 

  839. <dt>&lsquo;<samp>bitstream</samp>&rsquo;</dt>
    840. 

  840. <dt>&lsquo;<samp>mb_type</samp>&rsquo;</dt>
    841. 

  841. <dd><p>macroblock (MB) type
    842. 

  842. </p></dd>
    843. 

  843. <dt>&lsquo;<samp>qp</samp>&rsquo;</dt>
    844. 

  844. <dd><p>per-block quantization parameter (QP)
    845. 

  845. </p></dd>
    846. 

  846. <dt>&lsquo;<samp>dct_coeff</samp>&rsquo;</dt>
    847. 

  847. <dt>&lsquo;<samp>green_metadata</samp>&rsquo;</dt>
    848. 

  848. <dd><p>display complexity metadata for the upcoming frame, GoP or for a given duration.
    849. 

  849. </p>
    850. 

  850. </dd>
    851. 

  851. <dt>&lsquo;<samp>skip</samp>&rsquo;</dt>
    852. 

  852. <dt>&lsquo;<samp>startcode</samp>&rsquo;</dt>
    853. 

  853. <dt>&lsquo;<samp>er</samp>&rsquo;</dt>
    854. 

  854. <dd><p>error recognition
    855. 

  855. </p></dd>
    856. 

  856. <dt>&lsquo;<samp>mmco</samp>&rsquo;</dt>
    857. 

  857. <dd><p>memory management control operations (H.264)
    858. 

  858. </p></dd>
    859. 

  859. <dt>&lsquo;<samp>bugs</samp>&rsquo;</dt>
    860. 

  860. <dt>&lsquo;<samp>buffers</samp>&rsquo;</dt>
    861. 

  861. <dd><p>picture buffer allocations
    862. 

  862. </p></dd>
    863. 

  863. <dt>&lsquo;<samp>thread_ops</samp>&rsquo;</dt>
    864. 

  864. <dd><p>threading operations
    865. 

  865. </p></dd>
    866. 

  866. <dt>&lsquo;<samp>nomc</samp>&rsquo;</dt>
    867. 

  867. <dd><p>skip motion compensation
    868. 

  868. </p></dd>
    869. 

  869. </dl>
    870. 

  870. 

  871. </dd>
    872. 

  872. <dt>&lsquo;<samp>cmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    873. 

  873. <dd><p>Set full pel me compare function.
    874. 

  874. </p>
    875. 

  875. <p>Possible values:
    876. 

  876. </p><dl compact="compact">
    877. 

  877. <dt>&lsquo;<samp>sad</samp>&rsquo;</dt>
    878. 

  878. <dd><p>sum of absolute differences, fast (default)
    879. 

  879. </p></dd>
    880. 

  880. <dt>&lsquo;<samp>sse</samp>&rsquo;</dt>
    881. 

  881. <dd><p>sum of squared errors
    882. 

  882. </p></dd>
    883. 

  883. <dt>&lsquo;<samp>satd</samp>&rsquo;</dt>
    884. 

  884. <dd><p>sum of absolute Hadamard transformed differences
    885. 

  885. </p></dd>
    886. 

  886. <dt>&lsquo;<samp>dct</samp>&rsquo;</dt>
    887. 

  887. <dd><p>sum of absolute DCT transformed differences
    888. 

  888. </p></dd>
    889. 

  889. <dt>&lsquo;<samp>psnr</samp>&rsquo;</dt>
    890. 

  890. <dd><p>sum of squared quantization errors (avoid, low quality)
    891. 

  891. </p></dd>
    892. 

  892. <dt>&lsquo;<samp>bit</samp>&rsquo;</dt>
    893. 

  893. <dd><p>number of bits needed for the block
    894. 

  894. </p></dd>
    895. 

  895. <dt>&lsquo;<samp>rd</samp>&rsquo;</dt>
    896. 

  896. <dd><p>rate distortion optimal, slow
    897. 

  897. </p></dd>
    898. 

  898. <dt>&lsquo;<samp>zero</samp>&rsquo;</dt>
    899. 

  899. <dd><p>0
    900. 

  900. </p></dd>
    901. 

  901. <dt>&lsquo;<samp>vsad</samp>&rsquo;</dt>
    902. 

  902. <dd><p>sum of absolute vertical differences
    903. 

  903. </p></dd>
    904. 

  904. <dt>&lsquo;<samp>vsse</samp>&rsquo;</dt>
    905. 

  905. <dd><p>sum of squared vertical differences
    906. 

  906. </p></dd>
    907. 

  907. <dt>&lsquo;<samp>nsse</samp>&rsquo;</dt>
    908. 

  908. <dd><p>noise preserving sum of squared differences
    909. 

  909. </p></dd>
    910. 

  910. <dt>&lsquo;<samp>w53</samp>&rsquo;</dt>
    911. 

  911. <dd><p>5/3 wavelet, only used in snow
    912. 

  912. </p></dd>
    913. 

  913. <dt>&lsquo;<samp>w97</samp>&rsquo;</dt>
    914. 

  914. <dd><p>9/7 wavelet, only used in snow
    915. 

  915. </p></dd>
    916. 

  916. <dt>&lsquo;<samp>dctmax</samp>&rsquo;</dt>
    917. 

  917. <dt>&lsquo;<samp>chroma</samp>&rsquo;</dt>
    918. 

  918. </dl>
    919. 

  919. 

  920. </dd>
    921. 

  921. <dt>&lsquo;<samp>subcmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    922. 

  922. <dd><p>Set sub pel me compare function.
    923. 

  923. </p>
    924. 

  924. <p>Possible values:
    925. 

  925. </p><dl compact="compact">
    926. 

  926. <dt>&lsquo;<samp>sad</samp>&rsquo;</dt>
    927. 

  927. <dd><p>sum of absolute differences, fast (default)
    928. 

  928. </p></dd>
    929. 

  929. <dt>&lsquo;<samp>sse</samp>&rsquo;</dt>
    930. 

  930. <dd><p>sum of squared errors
    931. 

  931. </p></dd>
    932. 

  932. <dt>&lsquo;<samp>satd</samp>&rsquo;</dt>
    933. 

  933. <dd><p>sum of absolute Hadamard transformed differences
    934. 

  934. </p></dd>
    935. 

  935. <dt>&lsquo;<samp>dct</samp>&rsquo;</dt>
    936. 

  936. <dd><p>sum of absolute DCT transformed differences
    937. 

  937. </p></dd>
    938. 

  938. <dt>&lsquo;<samp>psnr</samp>&rsquo;</dt>
    939. 

  939. <dd><p>sum of squared quantization errors (avoid, low quality)
    940. 

  940. </p></dd>
    941. 

  941. <dt>&lsquo;<samp>bit</samp>&rsquo;</dt>
    942. 

  942. <dd><p>number of bits needed for the block
    943. 

  943. </p></dd>
    944. 

  944. <dt>&lsquo;<samp>rd</samp>&rsquo;</dt>
    945. 

  945. <dd><p>rate distortion optimal, slow
    946. 

  946. </p></dd>
    947. 

  947. <dt>&lsquo;<samp>zero</samp>&rsquo;</dt>
    948. 

  948. <dd><p>0
    949. 

  949. </p></dd>
    950. 

  950. <dt>&lsquo;<samp>vsad</samp>&rsquo;</dt>
    951. 

  951. <dd><p>sum of absolute vertical differences
    952. 

  952. </p></dd>
    953. 

  953. <dt>&lsquo;<samp>vsse</samp>&rsquo;</dt>
    954. 

  954. <dd><p>sum of squared vertical differences
    955. 

  955. </p></dd>
    956. 

  956. <dt>&lsquo;<samp>nsse</samp>&rsquo;</dt>
    957. 

  957. <dd><p>noise preserving sum of squared differences
    958. 

  958. </p></dd>
    959. 

  959. <dt>&lsquo;<samp>w53</samp>&rsquo;</dt>
    960. 

  960. <dd><p>5/3 wavelet, only used in snow
    961. 

  961. </p></dd>
    962. 

  962. <dt>&lsquo;<samp>w97</samp>&rsquo;</dt>
    963. 

  963. <dd><p>9/7 wavelet, only used in snow
    964. 

  964. </p></dd>
    965. 

  965. <dt>&lsquo;<samp>dctmax</samp>&rsquo;</dt>
    966. 

  966. <dt>&lsquo;<samp>chroma</samp>&rsquo;</dt>
    967. 

  967. </dl>
    968. 

  968. 

  969. </dd>
    970. 

  970. <dt>&lsquo;<samp>mbcmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    971. 

  971. <dd><p>Set macroblock compare function.
    972. 

  972. </p>
    973. 

  973. <p>Possible values:
    974. 

  974. </p><dl compact="compact">
    975. 

  975. <dt>&lsquo;<samp>sad</samp>&rsquo;</dt>
    976. 

  976. <dd><p>sum of absolute differences, fast (default)
    977. 

  977. </p></dd>
    978. 

  978. <dt>&lsquo;<samp>sse</samp>&rsquo;</dt>
    979. 

  979. <dd><p>sum of squared errors
    980. 

  980. </p></dd>
    981. 

  981. <dt>&lsquo;<samp>satd</samp>&rsquo;</dt>
    982. 

  982. <dd><p>sum of absolute Hadamard transformed differences
    983. 

  983. </p></dd>
    984. 

  984. <dt>&lsquo;<samp>dct</samp>&rsquo;</dt>
    985. 

  985. <dd><p>sum of absolute DCT transformed differences
    986. 

  986. </p></dd>
    987. 

  987. <dt>&lsquo;<samp>psnr</samp>&rsquo;</dt>
    988. 

  988. <dd><p>sum of squared quantization errors (avoid, low quality)
    989. 

  989. </p></dd>
    990. 

  990. <dt>&lsquo;<samp>bit</samp>&rsquo;</dt>
    991. 

  991. <dd><p>number of bits needed for the block
    992. 

  992. </p></dd>
    993. 

  993. <dt>&lsquo;<samp>rd</samp>&rsquo;</dt>
    994. 

  994. <dd><p>rate distortion optimal, slow
    995. 

  995. </p></dd>
    996. 

  996. <dt>&lsquo;<samp>zero</samp>&rsquo;</dt>
    997. 

  997. <dd><p>0
    998. 

  998. </p></dd>
    999. 

  999. <dt>&lsquo;<samp>vsad</samp>&rsquo;</dt>
    1000. 

  1000. <dd><p>sum of absolute vertical differences
    1001. 

  1001. </p></dd>
    1002. 

  1002. <dt>&lsquo;<samp>vsse</samp>&rsquo;</dt>
    1003. 

  1003. <dd><p>sum of squared vertical differences
    1004. 

  1004. </p></dd>
    1005. 

  1005. <dt>&lsquo;<samp>nsse</samp>&rsquo;</dt>
    1006. 

  1006. <dd><p>noise preserving sum of squared differences
    1007. 

  1007. </p></dd>
    1008. 

  1008. <dt>&lsquo;<samp>w53</samp>&rsquo;</dt>
    1009. 

  1009. <dd><p>5/3 wavelet, only used in snow
    1010. 

  1010. </p></dd>
    1011. 

  1011. <dt>&lsquo;<samp>w97</samp>&rsquo;</dt>
    1012. 

  1012. <dd><p>9/7 wavelet, only used in snow
    1013. 

  1013. </p></dd>
    1014. 

  1014. <dt>&lsquo;<samp>dctmax</samp>&rsquo;</dt>
    1015. 

  1015. <dt>&lsquo;<samp>chroma</samp>&rsquo;</dt>
    1016. 

  1016. </dl>
    1017. 

  1017. 

  1018. </dd>
    1019. 

  1019. <dt>&lsquo;<samp>ildctcmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1020. 

  1020. <dd><p>Set interlaced dct compare function.
    1021. 

  1021. </p>
    1022. 

  1022. <p>Possible values:
    1023. 

  1023. </p><dl compact="compact">
    1024. 

  1024. <dt>&lsquo;<samp>sad</samp>&rsquo;</dt>
    1025. 

  1025. <dd><p>sum of absolute differences, fast (default)
    1026. 

  1026. </p></dd>
    1027. 

  1027. <dt>&lsquo;<samp>sse</samp>&rsquo;</dt>
    1028. 

  1028. <dd><p>sum of squared errors
    1029. 

  1029. </p></dd>
    1030. 

  1030. <dt>&lsquo;<samp>satd</samp>&rsquo;</dt>
    1031. 

  1031. <dd><p>sum of absolute Hadamard transformed differences
    1032. 

  1032. </p></dd>
    1033. 

  1033. <dt>&lsquo;<samp>dct</samp>&rsquo;</dt>
    1034. 

  1034. <dd><p>sum of absolute DCT transformed differences
    1035. 

  1035. </p></dd>
    1036. 

  1036. <dt>&lsquo;<samp>psnr</samp>&rsquo;</dt>
    1037. 

  1037. <dd><p>sum of squared quantization errors (avoid, low quality)
    1038. 

  1038. </p></dd>
    1039. 

  1039. <dt>&lsquo;<samp>bit</samp>&rsquo;</dt>
    1040. 

  1040. <dd><p>number of bits needed for the block
    1041. 

  1041. </p></dd>
    1042. 

  1042. <dt>&lsquo;<samp>rd</samp>&rsquo;</dt>
    1043. 

  1043. <dd><p>rate distortion optimal, slow
    1044. 

  1044. </p></dd>
    1045. 

  1045. <dt>&lsquo;<samp>zero</samp>&rsquo;</dt>
    1046. 

  1046. <dd><p>0
    1047. 

  1047. </p></dd>
    1048. 

  1048. <dt>&lsquo;<samp>vsad</samp>&rsquo;</dt>
    1049. 

  1049. <dd><p>sum of absolute vertical differences
    1050. 

  1050. </p></dd>
    1051. 

  1051. <dt>&lsquo;<samp>vsse</samp>&rsquo;</dt>
    1052. 

  1052. <dd><p>sum of squared vertical differences
    1053. 

  1053. </p></dd>
    1054. 

  1054. <dt>&lsquo;<samp>nsse</samp>&rsquo;</dt>
    1055. 

  1055. <dd><p>noise preserving sum of squared differences
    1056. 

  1056. </p></dd>
    1057. 

  1057. <dt>&lsquo;<samp>w53</samp>&rsquo;</dt>
    1058. 

  1058. <dd><p>5/3 wavelet, only used in snow
    1059. 

  1059. </p></dd>
    1060. 

  1060. <dt>&lsquo;<samp>w97</samp>&rsquo;</dt>
    1061. 

  1061. <dd><p>9/7 wavelet, only used in snow
    1062. 

  1062. </p></dd>
    1063. 

  1063. <dt>&lsquo;<samp>dctmax</samp>&rsquo;</dt>
    1064. 

  1064. <dt>&lsquo;<samp>chroma</samp>&rsquo;</dt>
    1065. 

  1065. </dl>
    1066. 

  1066. 

  1067. </dd>
    1068. 

  1068. <dt>&lsquo;<samp>dia_size <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1069. 

  1069. <dd><p>Set diamond type &amp; size for motion estimation.
    1070. 

  1070. </p><dl compact="compact">
    1071. 

  1071. <dt>&lsquo;<samp>(1024, INT_MAX)</samp>&rsquo;</dt>
    1072. 

  1072. <dd><p>full motion estimation(slowest)
    1073. 

  1073. </p></dd>
    1074. 

  1074. <dt>&lsquo;<samp>(768, 1024]</samp>&rsquo;</dt>
    1075. 

  1075. <dd><p>umh motion estimation
    1076. 

  1076. </p></dd>
    1077. 

  1077. <dt>&lsquo;<samp>(512, 768]</samp>&rsquo;</dt>
    1078. 

  1078. <dd><p>hex motion estimation
    1079. 

  1079. </p></dd>
    1080. 

  1080. <dt>&lsquo;<samp>(256, 512]</samp>&rsquo;</dt>
    1081. 

  1081. <dd><p>l2s diamond motion estimation
    1082. 

  1082. </p></dd>
    1083. 

  1083. <dt>&lsquo;<samp>[2,256]</samp>&rsquo;</dt>
    1084. 

  1084. <dd><p>var diamond motion estimation
    1085. 

  1085. </p></dd>
    1086. 

  1086. <dt>&lsquo;<samp>(-1,  2)</samp>&rsquo;</dt>
    1087. 

  1087. <dd><p>small diamond motion estimation
    1088. 

  1088. </p></dd>
    1089. 

  1089. <dt>&lsquo;<samp>-1</samp>&rsquo;</dt>
    1090. 

  1090. <dd><p>funny diamond motion estimation
    1091. 

  1091. </p></dd>
    1092. 

  1092. <dt>&lsquo;<samp>(INT_MIN, -1)</samp>&rsquo;</dt>
    1093. 

  1093. <dd><p>sab diamond motion estimation
    1094. 

  1094. </p></dd>
    1095. 

  1095. </dl>
    1096. 

  1096. 

  1097. </dd>
    1098. 

  1098. <dt>&lsquo;<samp>last_pred <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1099. 

  1099. <dd><p>Set amount of motion predictors from the previous frame.
    1100. 

  1100. </p>
    1101. 

  1101. </dd>
    1102. 

  1102. <dt>&lsquo;<samp>preme <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1103. 

  1103. <dd><p>Set pre motion estimation.
    1104. 

  1104. </p>
    1105. 

  1105. </dd>
    1106. 

  1106. <dt>&lsquo;<samp>precmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1107. 

  1107. <dd><p>Set pre motion estimation compare function.
    1108. 

  1108. </p>
    1109. 

  1109. <p>Possible values:
    1110. 

  1110. </p><dl compact="compact">
    1111. 

  1111. <dt>&lsquo;<samp>sad</samp>&rsquo;</dt>
    1112. 

  1112. <dd><p>sum of absolute differences, fast (default)
    1113. 

  1113. </p></dd>
    1114. 

  1114. <dt>&lsquo;<samp>sse</samp>&rsquo;</dt>
    1115. 

  1115. <dd><p>sum of squared errors
    1116. 

  1116. </p></dd>
    1117. 

  1117. <dt>&lsquo;<samp>satd</samp>&rsquo;</dt>
    1118. 

  1118. <dd><p>sum of absolute Hadamard transformed differences
    1119. 

  1119. </p></dd>
    1120. 

  1120. <dt>&lsquo;<samp>dct</samp>&rsquo;</dt>
    1121. 

  1121. <dd><p>sum of absolute DCT transformed differences
    1122. 

  1122. </p></dd>
    1123. 

  1123. <dt>&lsquo;<samp>psnr</samp>&rsquo;</dt>
    1124. 

  1124. <dd><p>sum of squared quantization errors (avoid, low quality)
    1125. 

  1125. </p></dd>
    1126. 

  1126. <dt>&lsquo;<samp>bit</samp>&rsquo;</dt>
    1127. 

  1127. <dd><p>number of bits needed for the block
    1128. 

  1128. </p></dd>
    1129. 

  1129. <dt>&lsquo;<samp>rd</samp>&rsquo;</dt>
    1130. 

  1130. <dd><p>rate distortion optimal, slow
    1131. 

  1131. </p></dd>
    1132. 

  1132. <dt>&lsquo;<samp>zero</samp>&rsquo;</dt>
    1133. 

  1133. <dd><p>0
    1134. 

  1134. </p></dd>
    1135. 

  1135. <dt>&lsquo;<samp>vsad</samp>&rsquo;</dt>
    1136. 

  1136. <dd><p>sum of absolute vertical differences
    1137. 

  1137. </p></dd>
    1138. 

  1138. <dt>&lsquo;<samp>vsse</samp>&rsquo;</dt>
    1139. 

  1139. <dd><p>sum of squared vertical differences
    1140. 

  1140. </p></dd>
    1141. 

  1141. <dt>&lsquo;<samp>nsse</samp>&rsquo;</dt>
    1142. 

  1142. <dd><p>noise preserving sum of squared differences
    1143. 

  1143. </p></dd>
    1144. 

  1144. <dt>&lsquo;<samp>w53</samp>&rsquo;</dt>
    1145. 

  1145. <dd><p>5/3 wavelet, only used in snow
    1146. 

  1146. </p></dd>
    1147. 

  1147. <dt>&lsquo;<samp>w97</samp>&rsquo;</dt>
    1148. 

  1148. <dd><p>9/7 wavelet, only used in snow
    1149. 

  1149. </p></dd>
    1150. 

  1150. <dt>&lsquo;<samp>dctmax</samp>&rsquo;</dt>
    1151. 

  1151. <dt>&lsquo;<samp>chroma</samp>&rsquo;</dt>
    1152. 

  1152. </dl>
    1153. 

  1153. 

  1154. </dd>
    1155. 

  1155. <dt>&lsquo;<samp>pre_dia_size <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1156. 

  1156. <dd><p>Set diamond type &amp; size for motion estimation pre-pass.
    1157. 

  1157. </p>
    1158. 

  1158. </dd>
    1159. 

  1159. <dt>&lsquo;<samp>subq <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1160. 

  1160. <dd><p>Set sub pel motion estimation quality.
    1161. 

  1161. </p>
    1162. 

  1162. </dd>
    1163. 

  1163. <dt>&lsquo;<samp>dtg_active_format <var>integer</var></samp>&rsquo;</dt>
    1164. 

  1164. <dt>&lsquo;<samp>me_range <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1165. 

  1165. <dd><p>Set limit motion vectors range (1023 for DivX player).
    1166. 

  1166. </p>
    1167. 

  1167. </dd>
    1168. 

  1168. <dt>&lsquo;<samp>ibias <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1169. 

  1169. <dd><p>Set intra quant bias.
    1170. 

  1170. </p>
    1171. 

  1171. </dd>
    1172. 

  1172. <dt>&lsquo;<samp>pbias <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1173. 

  1173. <dd><p>Set inter quant bias.
    1174. 

  1174. </p>
    1175. 

  1175. </dd>
    1176. 

  1176. <dt>&lsquo;<samp>color_table_id <var>integer</var></samp>&rsquo;</dt>
    1177. 

  1177. <dt>&lsquo;<samp>global_quality <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
    1178. 

  1178. <dt>&lsquo;<samp>coder <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1179. 

  1179. <dd>
    1180. 

  1180. <p>Possible values:
    1181. 

  1181. </p><dl compact="compact">
    1182. 

  1182. <dt>&lsquo;<samp>vlc</samp>&rsquo;</dt>
    1183. 

  1183. <dd><p>variable length coder / huffman coder
    1184. 

  1184. </p></dd>
    1185. 

  1185. <dt>&lsquo;<samp>ac</samp>&rsquo;</dt>
    1186. 

  1186. <dd><p>arithmetic coder
    1187. 

  1187. </p></dd>
    1188. 

  1188. <dt>&lsquo;<samp>raw</samp>&rsquo;</dt>
    1189. 

  1189. <dd><p>raw (no encoding)
    1190. 

  1190. </p></dd>
    1191. 

  1191. <dt>&lsquo;<samp>rle</samp>&rsquo;</dt>
    1192. 

  1192. <dd><p>run-length coder
    1193. 

  1193. </p></dd>
    1194. 

  1194. <dt>&lsquo;<samp>deflate</samp>&rsquo;</dt>
    1195. 

  1195. <dd><p>deflate-based coder
    1196. 

  1196. </p></dd>
    1197. 

  1197. </dl>
    1198. 

  1198. 

  1199. </dd>
    1200. 

  1200. <dt>&lsquo;<samp>context <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1201. 

  1201. <dd><p>Set context model.
    1202. 

  1202. </p>
    1203. 

  1203. </dd>
    1204. 

  1204. <dt>&lsquo;<samp>slice_flags <var>integer</var></samp>&rsquo;</dt>
    1205. 

  1205. <dt>&lsquo;<samp>mbd <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1206. 

  1206. <dd><p>Set macroblock decision algorithm (high quality mode).
    1207. 

  1207. </p>
    1208. 

  1208. <p>Possible values:
    1209. 

  1209. </p><dl compact="compact">
    1210. 

  1210. <dt>&lsquo;<samp>simple</samp>&rsquo;</dt>
    1211. 

  1211. <dd><p>use mbcmp (default)
    1212. 

  1212. </p></dd>
    1213. 

  1213. <dt>&lsquo;<samp>bits</samp>&rsquo;</dt>
    1214. 

  1214. <dd><p>use fewest bits
    1215. 

  1215. </p></dd>
    1216. 

  1216. <dt>&lsquo;<samp>rd</samp>&rsquo;</dt>
    1217. 

  1217. <dd><p>use best rate distortion
    1218. 

  1218. </p></dd>
    1219. 

  1219. </dl>
    1220. 

  1220. 

  1221. </dd>
    1222. 

  1222. <dt>&lsquo;<samp>stream_codec_tag <var>integer</var></samp>&rsquo;</dt>
    1223. 

  1223. <dt>&lsquo;<samp>sc_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1224. 

  1224. <dd><p>Set scene change threshold.
    1225. 

  1225. </p>
    1226. 

  1226. </dd>
    1227. 

  1227. <dt>&lsquo;<samp>lmin <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1228. 

  1228. <dd><p>Set min lagrange factor (VBR).
    1229. 

  1229. </p>
    1230. 

  1230. </dd>
    1231. 

  1231. <dt>&lsquo;<samp>lmax <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1232. 

  1232. <dd><p>Set max lagrange factor (VBR).
    1233. 

  1233. </p>
    1234. 

  1234. </dd>
    1235. 

  1235. <dt>&lsquo;<samp>nr <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1236. 

  1236. <dd><p>Set noise reduction.
    1237. 

  1237. </p>
    1238. 

  1238. </dd>
    1239. 

  1239. <dt>&lsquo;<samp>rc_init_occupancy <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1240. 

  1240. <dd><p>Set number of bits which should be loaded into the rc buffer before
    1241. 

  1241. decoding starts.
    1242. 

  1242. </p>
    1243. 

  1243. </dd>
    1244. 

  1244. <dt>&lsquo;<samp>flags2 <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp>&rsquo;</dt>
    1245. 

  1245. <dd>
    1246. 

  1246. <p>Possible values:
    1247. 

  1247. </p><dl compact="compact">
    1248. 

  1248. <dt>&lsquo;<samp>fast</samp>&rsquo;</dt>
    1249. 

  1249. <dd><p>Allow non spec compliant speedup tricks.
    1250. 

  1250. </p></dd>
    1251. 

  1251. <dt>&lsquo;<samp>noout</samp>&rsquo;</dt>
    1252. 

  1252. <dd><p>Skip bitstream encoding.
    1253. 

  1253. </p></dd>
    1254. 

  1254. <dt>&lsquo;<samp>ignorecrop</samp>&rsquo;</dt>
    1255. 

  1255. <dd><p>Ignore cropping information from sps.
    1256. 

  1256. </p></dd>
    1257. 

  1257. <dt>&lsquo;<samp>local_header</samp>&rsquo;</dt>
    1258. 

  1258. <dd><p>Place global headers at every keyframe instead of in extradata.
    1259. 

  1259. </p></dd>
    1260. 

  1260. <dt>&lsquo;<samp>chunks</samp>&rsquo;</dt>
    1261. 

  1261. <dd><p>Frame data might be split into multiple chunks.
    1262. 

  1262. </p></dd>
    1263. 

  1263. <dt>&lsquo;<samp>showall</samp>&rsquo;</dt>
    1264. 

  1264. <dd><p>Show all frames before the first keyframe.
    1265. 

  1265. </p></dd>
    1266. 

  1266. <dt>&lsquo;<samp>export_mvs</samp>&rsquo;</dt>
    1267. 

  1267. <dd><p>Export motion vectors into frame side-data (see <code>AV_FRAME_DATA_MOTION_VECTORS</code>)
    1268. 

  1268. for codecs that support it. See also &lsquo;<tt>doc/examples/export_mvs.c</tt>&rsquo;.
    1269. 

  1269. </p></dd>
    1270. 

  1270. <dt>&lsquo;<samp>skip_manual</samp>&rsquo;</dt>
    1271. 

  1271. <dd><p>Do not skip samples and export skip information as frame side data.
    1272. 

  1272. </p></dd>
    1273. 

  1273. <dt>&lsquo;<samp>ass_ro_flush_noop</samp>&rsquo;</dt>
    1274. 

  1274. <dd><p>Do not reset ASS ReadOrder field on flush.
    1275. 

  1275. </p></dd>
    1276. 

  1276. </dl>
    1277. 

  1277. 

  1278. </dd>
    1279. 

  1279. <dt>&lsquo;<samp>export_side_data <var>flags</var> (<em>decoding/encoding,audio,video,subtitles</em>)</samp>&rsquo;</dt>
    1280. 

  1280. <dd>
    1281. 

  1281. <p>Possible values:
    1282. 

  1282. </p><dl compact="compact">
    1283. 

  1283. <dt>&lsquo;<samp>mvs</samp>&rsquo;</dt>
    1284. 

  1284. <dd><p>Export motion vectors into frame side-data (see <code>AV_FRAME_DATA_MOTION_VECTORS</code>)
    1285. 

  1285. for codecs that support it. See also &lsquo;<tt>doc/examples/export_mvs.c</tt>&rsquo;.
    1286. 

  1286. </p></dd>
    1287. 

  1287. <dt>&lsquo;<samp>prft</samp>&rsquo;</dt>
    1288. 

  1288. <dd><p>Export encoder Producer Reference Time into packet side-data (see <code>AV_PKT_DATA_PRFT</code>)
    1289. 

  1289. for codecs that support it.
    1290. 

  1290. </p></dd>
    1291. 

  1291. </dl>
    1292. 

  1292. 

  1293. </dd>
    1294. 

  1294. <dt>&lsquo;<samp>error <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1295. 

  1295. <dt>&lsquo;<samp>qns <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1296. 

  1296. <dd><p>Deprecated, use mpegvideo private options instead.
    1297. 

  1297. </p>
    1298. 

  1298. </dd>
    1299. 

  1299. <dt>&lsquo;<samp>threads <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
    1300. 

  1300. <dd><p>Set the number of threads to be used, in case the selected codec
    1301. 

  1301. implementation supports multi-threading.
    1302. 

  1302. </p>
    1303. 

  1303. <p>Possible values:
    1304. 

  1304. </p><dl compact="compact">
    1305. 

  1305. <dt>&lsquo;<samp>auto, 0</samp>&rsquo;</dt>
    1306. 

  1306. <dd><p>automatically select the number of threads to set
    1307. 

  1307. </p></dd>
    1308. 

  1308. </dl>
    1309. 

  1309. 

  1310. <p>Default value is &lsquo;<samp>auto</samp>&rsquo;.
    1311. 

  1311. </p>
    1312. 

  1312. </dd>
    1313. 

  1313. <dt>&lsquo;<samp>me_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1314. 

  1314. <dd><p>Set motion estimation threshold.
    1315. 

  1315. </p>
    1316. 

  1316. </dd>
    1317. 

  1317. <dt>&lsquo;<samp>mb_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1318. 

  1318. <dd><p>Set macroblock threshold.
    1319. 

  1319. </p>
    1320. 

  1320. </dd>
    1321. 

  1321. <dt>&lsquo;<samp>dc <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1322. 

  1322. <dd><p>Set intra_dc_precision.
    1323. 

  1323. </p>
    1324. 

  1324. </dd>
    1325. 

  1325. <dt>&lsquo;<samp>nssew <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1326. 

  1326. <dd><p>Set nsse weight.
    1327. 

  1327. </p>
    1328. 

  1328. </dd>
    1329. 

  1329. <dt>&lsquo;<samp>skip_top <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
    1330. 

  1330. <dd><p>Set number of macroblock rows at the top which are skipped.
    1331. 

  1331. </p>
    1332. 

  1332. </dd>
    1333. 

  1333. <dt>&lsquo;<samp>skip_bottom <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
    1334. 

  1334. <dd><p>Set number of macroblock rows at the bottom which are skipped.
    1335. 

  1335. </p>
    1336. 

  1336. </dd>
    1337. 

  1337. <dt>&lsquo;<samp>profile <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
    1338. 

  1338. <dd>
    1339. 

  1339. <p>Set encoder codec profile. Default value is &lsquo;<samp>unknown</samp>&rsquo;. Encoder specific
    1340. 

  1340. profiles are documented in the relevant encoder documentation.
    1341. 

  1341. </p>
    1342. 

  1342. </dd>
    1343. 

  1343. <dt>&lsquo;<samp>level <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
    1344. 

  1344. <dd>
    1345. 

  1345. <p>Possible values:
    1346. 

  1346. </p><dl compact="compact">
    1347. 

  1347. <dt>&lsquo;<samp>unknown</samp>&rsquo;</dt>
    1348. 

  1348. </dl>
    1349. 

  1349. 

  1350. </dd>
    1351. 

  1351. <dt>&lsquo;<samp>lowres <var>integer</var> (<em>decoding,audio,video</em>)</samp>&rsquo;</dt>
    1352. 

  1352. <dd><p>Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.
    1353. 

  1353. </p>
    1354. 

  1354. </dd>
    1355. 

  1355. <dt>&lsquo;<samp>skip_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1356. 

  1356. <dd><p>Set frame skip threshold.
    1357. 

  1357. </p>
    1358. 

  1358. </dd>
    1359. 

  1359. <dt>&lsquo;<samp>skip_factor <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1360. 

  1360. <dd><p>Set frame skip factor.
    1361. 

  1361. </p>
    1362. 

  1362. </dd>
    1363. 

  1363. <dt>&lsquo;<samp>skip_exp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1364. 

  1364. <dd><p>Set frame skip exponent.
    1365. 

  1365. Negative values behave identical to the corresponding positive ones, except
    1366. 

  1366. that the score is normalized.
    1367. 

  1367. Positive values exist primarily for compatibility reasons and are not so useful.
    1368. 

  1368. </p>
    1369. 

  1369. </dd>
    1370. 

  1370. <dt>&lsquo;<samp>skipcmp <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1371. 

  1371. <dd><p>Set frame skip compare function.
    1372. 

  1372. </p>
    1373. 

  1373. <p>Possible values:
    1374. 

  1374. </p><dl compact="compact">
    1375. 

  1375. <dt>&lsquo;<samp>sad</samp>&rsquo;</dt>
    1376. 

  1376. <dd><p>sum of absolute differences, fast (default)
    1377. 

  1377. </p></dd>
    1378. 

  1378. <dt>&lsquo;<samp>sse</samp>&rsquo;</dt>
    1379. 

  1379. <dd><p>sum of squared errors
    1380. 

  1380. </p></dd>
    1381. 

  1381. <dt>&lsquo;<samp>satd</samp>&rsquo;</dt>
    1382. 

  1382. <dd><p>sum of absolute Hadamard transformed differences
    1383. 

  1383. </p></dd>
    1384. 

  1384. <dt>&lsquo;<samp>dct</samp>&rsquo;</dt>
    1385. 

  1385. <dd><p>sum of absolute DCT transformed differences
    1386. 

  1386. </p></dd>
    1387. 

  1387. <dt>&lsquo;<samp>psnr</samp>&rsquo;</dt>
    1388. 

  1388. <dd><p>sum of squared quantization errors (avoid, low quality)
    1389. 

  1389. </p></dd>
    1390. 

  1390. <dt>&lsquo;<samp>bit</samp>&rsquo;</dt>
    1391. 

  1391. <dd><p>number of bits needed for the block
    1392. 

  1392. </p></dd>
    1393. 

  1393. <dt>&lsquo;<samp>rd</samp>&rsquo;</dt>
    1394. 

  1394. <dd><p>rate distortion optimal, slow
    1395. 

  1395. </p></dd>
    1396. 

  1396. <dt>&lsquo;<samp>zero</samp>&rsquo;</dt>
    1397. 

  1397. <dd><p>0
    1398. 

  1398. </p></dd>
    1399. 

  1399. <dt>&lsquo;<samp>vsad</samp>&rsquo;</dt>
    1400. 

  1400. <dd><p>sum of absolute vertical differences
    1401. 

  1401. </p></dd>
    1402. 

  1402. <dt>&lsquo;<samp>vsse</samp>&rsquo;</dt>
    1403. 

  1403. <dd><p>sum of squared vertical differences
    1404. 

  1404. </p></dd>
    1405. 

  1405. <dt>&lsquo;<samp>nsse</samp>&rsquo;</dt>
    1406. 

  1406. <dd><p>noise preserving sum of squared differences
    1407. 

  1407. </p></dd>
    1408. 

  1408. <dt>&lsquo;<samp>w53</samp>&rsquo;</dt>
    1409. 

  1409. <dd><p>5/3 wavelet, only used in snow
    1410. 

  1410. </p></dd>
    1411. 

  1411. <dt>&lsquo;<samp>w97</samp>&rsquo;</dt>
    1412. 

  1412. <dd><p>9/7 wavelet, only used in snow
    1413. 

  1413. </p></dd>
    1414. 

  1414. <dt>&lsquo;<samp>dctmax</samp>&rsquo;</dt>
    1415. 

  1415. <dt>&lsquo;<samp>chroma</samp>&rsquo;</dt>
    1416. 

  1416. </dl>
    1417. 

  1417. 

  1418. </dd>
    1419. 

  1419. <dt>&lsquo;<samp>border_mask <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1420. 

  1420. <dd><p>Increase the quantizer for macroblocks close to borders.
    1421. 

  1421. </p>
    1422. 

  1422. </dd>
    1423. 

  1423. <dt>&lsquo;<samp>mblmin <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1424. 

  1424. <dd><p>Set min macroblock lagrange factor (VBR).
    1425. 

  1425. </p>
    1426. 

  1426. </dd>
    1427. 

  1427. <dt>&lsquo;<samp>mblmax <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1428. 

  1428. <dd><p>Set max macroblock lagrange factor (VBR).
    1429. 

  1429. </p>
    1430. 

  1430. </dd>
    1431. 

  1431. <dt>&lsquo;<samp>mepc <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1432. 

  1432. <dd><p>Set motion estimation bitrate penalty compensation (1.0 = 256).
    1433. 

  1433. </p>
    1434. 

  1434. </dd>
    1435. 

  1435. <dt>&lsquo;<samp>skip_loop_filter <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
    1436. 

  1436. <dt>&lsquo;<samp>skip_idct        <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
    1437. 

  1437. <dt>&lsquo;<samp>skip_frame       <var>integer</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
    1438. 

  1438. <dd>
    1439. 

  1439. <p>Make decoder discard processing depending on the frame type selected
    1440. 

  1440. by the option value.
    1441. 

  1441. </p>
    1442. 

  1442. <p>&lsquo;<samp>skip_loop_filter</samp>&rsquo; skips frame loop filtering, &lsquo;<samp>skip_idct</samp>&rsquo;
    1443. 

  1443. skips frame IDCT/dequantization, &lsquo;<samp>skip_frame</samp>&rsquo; skips decoding.
    1444. 

  1444. </p>
    1445. 

  1445. <p>Possible values:
    1446. 

  1446. </p><dl compact="compact">
    1447. 

  1447. <dt>&lsquo;<samp>none</samp>&rsquo;</dt>
    1448. 

  1448. <dd><p>Discard no frame.
    1449. 

  1449. </p>
    1450. 

  1450. </dd>
    1451. 

  1451. <dt>&lsquo;<samp>default</samp>&rsquo;</dt>
    1452. 

  1452. <dd><p>Discard useless frames like 0-sized frames.
    1453. 

  1453. </p>
    1454. 

  1454. </dd>
    1455. 

  1455. <dt>&lsquo;<samp>noref</samp>&rsquo;</dt>
    1456. 

  1456. <dd><p>Discard all non-reference frames.
    1457. 

  1457. </p>
    1458. 

  1458. </dd>
    1459. 

  1459. <dt>&lsquo;<samp>bidir</samp>&rsquo;</dt>
    1460. 

  1460. <dd><p>Discard all bidirectional frames.
    1461. 

  1461. </p>
    1462. 

  1462. </dd>
    1463. 

  1463. <dt>&lsquo;<samp>nokey</samp>&rsquo;</dt>
    1464. 

  1464. <dd><p>Discard all frames excepts keyframes.
    1465. 

  1465. </p>
    1466. 

  1466. </dd>
    1467. 

  1467. <dt>&lsquo;<samp>nointra</samp>&rsquo;</dt>
    1468. 

  1468. <dd><p>Discard all frames except I frames.
    1469. 

  1469. </p>
    1470. 

  1470. </dd>
    1471. 

  1471. <dt>&lsquo;<samp>all</samp>&rsquo;</dt>
    1472. 

  1472. <dd><p>Discard all frames.
    1473. 

  1473. </p></dd>
    1474. 

  1474. </dl>
    1475. 

  1475. 

  1476. <p>Default value is &lsquo;<samp>default</samp>&rsquo;.
    1477. 

  1477. </p>
    1478. 

  1478. </dd>
    1479. 

  1479. <dt>&lsquo;<samp>bidir_refine <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1480. 

  1480. <dd><p>Refine the two motion vectors used in bidirectional macroblocks.
    1481. 

  1481. </p>
    1482. 

  1482. </dd>
    1483. 

  1483. <dt>&lsquo;<samp>brd_scale <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1484. 

  1484. <dd><p>Downscale frames for dynamic B-frame decision.
    1485. 

  1485. </p>
    1486. 

  1486. </dd>
    1487. 

  1487. <dt>&lsquo;<samp>keyint_min <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1488. 

  1488. <dd><p>Set minimum interval between IDR-frames.
    1489. 

  1489. </p>
    1490. 

  1490. </dd>
    1491. 

  1491. <dt>&lsquo;<samp>refs <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1492. 

  1492. <dd><p>Set reference frames to consider for motion compensation.
    1493. 

  1493. </p>
    1494. 

  1494. </dd>
    1495. 

  1495. <dt>&lsquo;<samp>chromaoffset <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1496. 

  1496. <dd><p>Set chroma qp offset from luma.
    1497. 

  1497. </p>
    1498. 

  1498. </dd>
    1499. 

  1499. <dt>&lsquo;<samp>trellis <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
    1500. 

  1500. <dd><p>Set rate-distortion optimal quantization.
    1501. 

  1501. </p>
    1502. 

  1502. </dd>
    1503. 

  1503. <dt>&lsquo;<samp>mv0_threshold <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1504. 

  1504. <dt>&lsquo;<samp>b_sensitivity <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1505. 

  1505. <dd><p>Adjust sensitivity of b_frame_strategy 1.
    1506. 

  1506. </p>
    1507. 

  1507. </dd>
    1508. 

  1508. <dt>&lsquo;<samp>compression_level <var>integer</var> (<em>encoding,audio,video</em>)</samp>&rsquo;</dt>
    1509. 

  1509. <dt>&lsquo;<samp>min_prediction_order <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
    1510. 

  1510. <dt>&lsquo;<samp>max_prediction_order <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
    1511. 

  1511. <dt>&lsquo;<samp>timecode_frame_start <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1512. 

  1512. <dd><p>Set GOP timecode frame start number, in non drop frame format.
    1513. 

  1513. </p>
    1514. 

  1514. </dd>
    1515. 

  1515. <dt>&lsquo;<samp>request_channels <var>integer</var> (<em>decoding,audio</em>)</samp>&rsquo;</dt>
    1516. 

  1516. <dd><p>Set desired number of audio channels.
    1517. 

  1517. </p>
    1518. 

  1518. </dd>
    1519. 

  1519. <dt>&lsquo;<samp>bits_per_raw_sample <var>integer</var></samp>&rsquo;</dt>
    1520. 

  1520. <dt>&lsquo;<samp>channel_layout <var>integer</var> (<em>decoding/encoding,audio</em>)</samp>&rsquo;</dt>
    1521. 

  1521. <dd>
    1522. 

  1522. <p>Possible values:
    1523. 

  1523. </p></dd>
    1524. 

  1524. <dt>&lsquo;<samp>request_channel_layout <var>integer</var> (<em>decoding,audio</em>)</samp>&rsquo;</dt>
    1525. 

  1525. <dd>
    1526. 

  1526. <p>Possible values:
    1527. 

  1527. </p></dd>
    1528. 

  1528. <dt>&lsquo;<samp>rc_max_vbv_use <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1529. 

  1529. <dt>&lsquo;<samp>rc_min_vbv_use <var>float</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1530. 

  1530. <dt>&lsquo;<samp>ticks_per_frame <var>integer</var> (<em>decoding/encoding,audio,video</em>)</samp>&rsquo;</dt>
    1531. 

  1531. <dt>&lsquo;<samp>color_primaries <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
    1532. 

  1532. <dd><p>Possible values:
    1533. 

  1533. </p><dl compact="compact">
    1534. 

  1534. <dt>&lsquo;<samp>bt709</samp>&rsquo;</dt>
    1535. 

  1535. <dd><p>BT.709
    1536. 

  1536. </p></dd>
    1537. 

  1537. <dt>&lsquo;<samp>bt470m</samp>&rsquo;</dt>
    1538. 

  1538. <dd><p>BT.470 M
    1539. 

  1539. </p></dd>
    1540. 

  1540. <dt>&lsquo;<samp>bt470bg</samp>&rsquo;</dt>
    1541. 

  1541. <dd><p>BT.470 BG
    1542. 

  1542. </p></dd>
    1543. 

  1543. <dt>&lsquo;<samp>smpte170m</samp>&rsquo;</dt>
    1544. 

  1544. <dd><p>SMPTE 170 M
    1545. 

  1545. </p></dd>
    1546. 

  1546. <dt>&lsquo;<samp>smpte240m</samp>&rsquo;</dt>
    1547. 

  1547. <dd><p>SMPTE 240 M
    1548. 

  1548. </p></dd>
    1549. 

  1549. <dt>&lsquo;<samp>film</samp>&rsquo;</dt>
    1550. 

  1550. <dd><p>Film
    1551. 

  1551. </p></dd>
    1552. 

  1552. <dt>&lsquo;<samp>bt2020</samp>&rsquo;</dt>
    1553. 

  1553. <dd><p>BT.2020
    1554. 

  1554. </p></dd>
    1555. 

  1555. <dt>&lsquo;<samp>smpte428</samp>&rsquo;</dt>
    1556. 

  1556. <dt>&lsquo;<samp>smpte428_1</samp>&rsquo;</dt>
    1557. 

  1557. <dd><p>SMPTE ST 428-1
    1558. 

  1558. </p></dd>
    1559. 

  1559. <dt>&lsquo;<samp>smpte431</samp>&rsquo;</dt>
    1560. 

  1560. <dd><p>SMPTE 431-2
    1561. 

  1561. </p></dd>
    1562. 

  1562. <dt>&lsquo;<samp>smpte432</samp>&rsquo;</dt>
    1563. 

  1563. <dd><p>SMPTE 432-1
    1564. 

  1564. </p></dd>
    1565. 

  1565. <dt>&lsquo;<samp>jedec-p22</samp>&rsquo;</dt>
    1566. 

  1566. <dd><p>JEDEC P22
    1567. 

  1567. </p></dd>
    1568. 

  1568. </dl>
    1569. 

  1569. 

  1570. </dd>
    1571. 

  1571. <dt>&lsquo;<samp>color_trc <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
    1572. 

  1572. <dd><p>Possible values:
    1573. 

  1573. </p><dl compact="compact">
    1574. 

  1574. <dt>&lsquo;<samp>bt709</samp>&rsquo;</dt>
    1575. 

  1575. <dd><p>BT.709
    1576. 

  1576. </p></dd>
    1577. 

  1577. <dt>&lsquo;<samp>gamma22</samp>&rsquo;</dt>
    1578. 

  1578. <dd><p>BT.470 M
    1579. 

  1579. </p></dd>
    1580. 

  1580. <dt>&lsquo;<samp>gamma28</samp>&rsquo;</dt>
    1581. 

  1581. <dd><p>BT.470 BG
    1582. 

  1582. </p></dd>
    1583. 

  1583. <dt>&lsquo;<samp>smpte170m</samp>&rsquo;</dt>
    1584. 

  1584. <dd><p>SMPTE 170 M
    1585. 

  1585. </p></dd>
    1586. 

  1586. <dt>&lsquo;<samp>smpte240m</samp>&rsquo;</dt>
    1587. 

  1587. <dd><p>SMPTE 240 M
    1588. 

  1588. </p></dd>
    1589. 

  1589. <dt>&lsquo;<samp>linear</samp>&rsquo;</dt>
    1590. 

  1590. <dd><p>Linear
    1591. 

  1591. </p></dd>
    1592. 

  1592. <dt>&lsquo;<samp>log</samp>&rsquo;</dt>
    1593. 

  1593. <dt>&lsquo;<samp>log100</samp>&rsquo;</dt>
    1594. 

  1594. <dd><p>Log
    1595. 

  1595. </p></dd>
    1596. 

  1596. <dt>&lsquo;<samp>log_sqrt</samp>&rsquo;</dt>
    1597. 

  1597. <dt>&lsquo;<samp>log316</samp>&rsquo;</dt>
    1598. 

  1598. <dd><p>Log square root
    1599. 

  1599. </p></dd>
    1600. 

  1600. <dt>&lsquo;<samp>iec61966_2_4</samp>&rsquo;</dt>
    1601. 

  1601. <dt>&lsquo;<samp>iec61966-2-4</samp>&rsquo;</dt>
    1602. 

  1602. <dd><p>IEC 61966-2-4
    1603. 

  1603. </p></dd>
    1604. 

  1604. <dt>&lsquo;<samp>bt1361</samp>&rsquo;</dt>
    1605. 

  1605. <dt>&lsquo;<samp>bt1361e</samp>&rsquo;</dt>
    1606. 

  1606. <dd><p>BT.1361
    1607. 

  1607. </p></dd>
    1608. 

  1608. <dt>&lsquo;<samp>iec61966_2_1</samp>&rsquo;</dt>
    1609. 

  1609. <dt>&lsquo;<samp>iec61966-2-1</samp>&rsquo;</dt>
    1610. 

  1610. <dd><p>IEC 61966-2-1
    1611. 

  1611. </p></dd>
    1612. 

  1612. <dt>&lsquo;<samp>bt2020_10</samp>&rsquo;</dt>
    1613. 

  1613. <dt>&lsquo;<samp>bt2020_10bit</samp>&rsquo;</dt>
    1614. 

  1614. <dd><p>BT.2020 - 10 bit
    1615. 

  1615. </p></dd>
    1616. 

  1616. <dt>&lsquo;<samp>bt2020_12</samp>&rsquo;</dt>
    1617. 

  1617. <dt>&lsquo;<samp>bt2020_12bit</samp>&rsquo;</dt>
    1618. 

  1618. <dd><p>BT.2020 - 12 bit
    1619. 

  1619. </p></dd>
    1620. 

  1620. <dt>&lsquo;<samp>smpte2084</samp>&rsquo;</dt>
    1621. 

  1621. <dd><p>SMPTE ST 2084
    1622. 

  1622. </p></dd>
    1623. 

  1623. <dt>&lsquo;<samp>smpte428</samp>&rsquo;</dt>
    1624. 

  1624. <dt>&lsquo;<samp>smpte428_1</samp>&rsquo;</dt>
    1625. 

  1625. <dd><p>SMPTE ST 428-1
    1626. 

  1626. </p></dd>
    1627. 

  1627. <dt>&lsquo;<samp>arib-std-b67</samp>&rsquo;</dt>
    1628. 

  1628. <dd><p>ARIB STD-B67
    1629. 

  1629. </p></dd>
    1630. 

  1630. </dl>
    1631. 

  1631. 

  1632. </dd>
    1633. 

  1633. <dt>&lsquo;<samp>colorspace <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
    1634. 

  1634. <dd><p>Possible values:
    1635. 

  1635. </p><dl compact="compact">
    1636. 

  1636. <dt>&lsquo;<samp>rgb</samp>&rsquo;</dt>
    1637. 

  1637. <dd><p>RGB
    1638. 

  1638. </p></dd>
    1639. 

  1639. <dt>&lsquo;<samp>bt709</samp>&rsquo;</dt>
    1640. 

  1640. <dd><p>BT.709
    1641. 

  1641. </p></dd>
    1642. 

  1642. <dt>&lsquo;<samp>fcc</samp>&rsquo;</dt>
    1643. 

  1643. <dd><p>FCC
    1644. 

  1644. </p></dd>
    1645. 

  1645. <dt>&lsquo;<samp>bt470bg</samp>&rsquo;</dt>
    1646. 

  1646. <dd><p>BT.470 BG
    1647. 

  1647. </p></dd>
    1648. 

  1648. <dt>&lsquo;<samp>smpte170m</samp>&rsquo;</dt>
    1649. 

  1649. <dd><p>SMPTE 170 M
    1650. 

  1650. </p></dd>
    1651. 

  1651. <dt>&lsquo;<samp>smpte240m</samp>&rsquo;</dt>
    1652. 

  1652. <dd><p>SMPTE 240 M
    1653. 

  1653. </p></dd>
    1654. 

  1654. <dt>&lsquo;<samp>ycocg</samp>&rsquo;</dt>
    1655. 

  1655. <dd><p>YCOCG
    1656. 

  1656. </p></dd>
    1657. 

  1657. <dt>&lsquo;<samp>bt2020nc</samp>&rsquo;</dt>
    1658. 

  1658. <dt>&lsquo;<samp>bt2020_ncl</samp>&rsquo;</dt>
    1659. 

  1659. <dd><p>BT.2020 NCL
    1660. 

  1660. </p></dd>
    1661. 

  1661. <dt>&lsquo;<samp>bt2020c</samp>&rsquo;</dt>
    1662. 

  1662. <dt>&lsquo;<samp>bt2020_cl</samp>&rsquo;</dt>
    1663. 

  1663. <dd><p>BT.2020 CL
    1664. 

  1664. </p></dd>
    1665. 

  1665. <dt>&lsquo;<samp>smpte2085</samp>&rsquo;</dt>
    1666. 

  1666. <dd><p>SMPTE 2085
    1667. 

  1667. </p></dd>
    1668. 

  1668. </dl>
    1669. 

  1669. 

  1670. </dd>
    1671. 

  1671. <dt>&lsquo;<samp>color_range <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
    1672. 

  1672. <dd><p>If used as input parameter, it serves as a hint to the decoder, which
    1673. 

  1673. color_range the input has.
    1674. 

  1674. Possible values:
    1675. 

  1675. </p><dl compact="compact">
    1676. 

  1676. <dt>&lsquo;<samp>tv</samp>&rsquo;</dt>
    1677. 

  1677. <dt>&lsquo;<samp>mpeg</samp>&rsquo;</dt>
    1678. 

  1678. <dd><p>MPEG (219*2^(n-8))
    1679. 

  1679. </p></dd>
    1680. 

  1680. <dt>&lsquo;<samp>pc</samp>&rsquo;</dt>
    1681. 

  1681. <dt>&lsquo;<samp>jpeg</samp>&rsquo;</dt>
    1682. 

  1682. <dd><p>JPEG (2^n-1)
    1683. 

  1683. </p></dd>
    1684. 

  1684. </dl>
    1685. 

  1685. 

  1686. </dd>
    1687. 

  1687. <dt>&lsquo;<samp>chroma_sample_location <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
    1688. 

  1688. <dd><p>Possible values:
    1689. 

  1689. </p><dl compact="compact">
    1690. 

  1690. <dt>&lsquo;<samp>left</samp>&rsquo;</dt>
    1691. 

  1691. <dt>&lsquo;<samp>center</samp>&rsquo;</dt>
    1692. 

  1692. <dt>&lsquo;<samp>topleft</samp>&rsquo;</dt>
    1693. 

  1693. <dt>&lsquo;<samp>top</samp>&rsquo;</dt>
    1694. 

  1694. <dt>&lsquo;<samp>bottomleft</samp>&rsquo;</dt>
    1695. 

  1695. <dt>&lsquo;<samp>bottom</samp>&rsquo;</dt>
    1696. 

  1696. </dl>
    1697. 

  1697. 

  1698. </dd>
    1699. 

  1699. <dt>&lsquo;<samp>log_level_offset <var>integer</var></samp>&rsquo;</dt>
    1700. 

  1700. <dd><p>Set the log level offset.
    1701. 

  1701. </p>
    1702. 

  1702. </dd>
    1703. 

  1703. <dt>&lsquo;<samp>slices <var>integer</var> (<em>encoding,video</em>)</samp>&rsquo;</dt>
    1704. 

  1704. <dd><p>Number of slices, used in parallelized encoding.
    1705. 

  1705. </p>
    1706. 

  1706. </dd>
    1707. 

  1707. <dt>&lsquo;<samp>thread_type <var>flags</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
    1708. 

  1708. <dd><p>Select which multithreading methods to use.
    1709. 

  1709. </p>
    1710. 

  1710. <p>Use of &lsquo;<samp>frame</samp>&rsquo; will increase decoding delay by one frame per
    1711. 

  1711. thread, so clients which cannot provide future frames should not use
    1712. 

  1712. it.
    1713. 

  1713. </p>
    1714. 

  1714. <p>Possible values:
    1715. 

  1715. </p><dl compact="compact">
    1716. 

  1716. <dt>&lsquo;<samp>slice</samp>&rsquo;</dt>
    1717. 

  1717. <dd><p>Decode more than one part of a single frame at once.
    1718. 

  1718. </p>
    1719. 

  1719. <p>Multithreading using slices works only when the video was encoded with
    1720. 

  1720. slices.
    1721. 

  1721. </p>
    1722. 

  1722. </dd>
    1723. 

  1723. <dt>&lsquo;<samp>frame</samp>&rsquo;</dt>
    1724. 

  1724. <dd><p>Decode more than one frame at once.
    1725. 

  1725. </p></dd>
    1726. 

  1726. </dl>
    1727. 

  1727. 

  1728. <p>Default value is &lsquo;<samp>slice+frame</samp>&rsquo;.
    1729. 

  1729. </p>
    1730. 

  1730. </dd>
    1731. 

  1731. <dt>&lsquo;<samp>audio_service_type <var>integer</var> (<em>encoding,audio</em>)</samp>&rsquo;</dt>
    1732. 

  1732. <dd><p>Set audio service type.
    1733. 

  1733. </p>
    1734. 

  1734. <p>Possible values:
    1735. 

  1735. </p><dl compact="compact">
    1736. 

  1736. <dt>&lsquo;<samp>ma</samp>&rsquo;</dt>
    1737. 

  1737. <dd><p>Main Audio Service
    1738. 

  1738. </p></dd>
    1739. 

  1739. <dt>&lsquo;<samp>ef</samp>&rsquo;</dt>
    1740. 

  1740. <dd><p>Effects
    1741. 

  1741. </p></dd>
    1742. 

  1742. <dt>&lsquo;<samp>vi</samp>&rsquo;</dt>
    1743. 

  1743. <dd><p>Visually Impaired
    1744. 

  1744. </p></dd>
    1745. 

  1745. <dt>&lsquo;<samp>hi</samp>&rsquo;</dt>
    1746. 

  1746. <dd><p>Hearing Impaired
    1747. 

  1747. </p></dd>
    1748. 

  1748. <dt>&lsquo;<samp>di</samp>&rsquo;</dt>
    1749. 

  1749. <dd><p>Dialogue
    1750. 

  1750. </p></dd>
    1751. 

  1751. <dt>&lsquo;<samp>co</samp>&rsquo;</dt>
    1752. 

  1752. <dd><p>Commentary
    1753. 

  1753. </p></dd>
    1754. 

  1754. <dt>&lsquo;<samp>em</samp>&rsquo;</dt>
    1755. 

  1755. <dd><p>Emergency
    1756. 

  1756. </p></dd>
    1757. 

  1757. <dt>&lsquo;<samp>vo</samp>&rsquo;</dt>
    1758. 

  1758. <dd><p>Voice Over
    1759. 

  1759. </p></dd>
    1760. 

  1760. <dt>&lsquo;<samp>ka</samp>&rsquo;</dt>
    1761. 

  1761. <dd><p>Karaoke
    1762. 

  1762. </p></dd>
    1763. 

  1763. </dl>
    1764. 

  1764. 

  1765. </dd>
    1766. 

  1766. <dt>&lsquo;<samp>request_sample_fmt <var>sample_fmt</var> (<em>decoding,audio</em>)</samp>&rsquo;</dt>
    1767. 

  1767. <dd><p>Set sample format audio decoders should prefer. Default value is
    1768. 

  1768. <code>none</code>.
    1769. 

  1769. </p>
    1770. 

  1770. </dd>
    1771. 

  1771. <dt>&lsquo;<samp>pkt_timebase <var>rational number</var></samp>&rsquo;</dt>
    1772. 

  1772. <dt>&lsquo;<samp>sub_charenc <var>encoding</var> (<em>decoding,subtitles</em>)</samp>&rsquo;</dt>
    1773. 

  1773. <dd><p>Set the input subtitles character encoding.
    1774. 

  1774. </p>
    1775. 

  1775. </dd>
    1776. 

  1776. <dt>&lsquo;<samp>field_order  <var>field_order</var> (<em>video</em>)</samp>&rsquo;</dt>
    1777. 

  1777. <dd><p>Set/override the field order of the video.
    1778. 

  1778. Possible values:
    1779. 

  1779. </p><dl compact="compact">
    1780. 

  1780. <dt>&lsquo;<samp>progressive</samp>&rsquo;</dt>
    1781. 

  1781. <dd><p>Progressive video
    1782. 

  1782. </p></dd>
    1783. 

  1783. <dt>&lsquo;<samp>tt</samp>&rsquo;</dt>
    1784. 

  1784. <dd><p>Interlaced video, top field coded and displayed first
    1785. 

  1785. </p></dd>
    1786. 

  1786. <dt>&lsquo;<samp>bb</samp>&rsquo;</dt>
    1787. 

  1787. <dd><p>Interlaced video, bottom field coded and displayed first
    1788. 

  1788. </p></dd>
    1789. 

  1789. <dt>&lsquo;<samp>tb</samp>&rsquo;</dt>
    1790. 

  1790. <dd><p>Interlaced video, top coded first, bottom displayed first
    1791. 

  1791. </p></dd>
    1792. 

  1792. <dt>&lsquo;<samp>bt</samp>&rsquo;</dt>
    1793. 

  1793. <dd><p>Interlaced video, bottom coded first, top displayed first
    1794. 

  1794. </p></dd>
    1795. 

  1795. </dl>
    1796. 

  1796. 

  1797. </dd>
    1798. 

  1798. <dt>&lsquo;<samp>skip_alpha <var>bool</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
    1799. 

  1799. <dd><p>Set to 1 to disable processing alpha (transparency). This works like the
    1800. 

  1800. &lsquo;<samp>gray</samp>&rsquo; flag in the &lsquo;<samp>flags</samp>&rsquo; option which skips chroma information
    1801. 

  1801. instead of alpha. Default is 0.
    1802. 

  1802. </p>
    1803. 

  1803. </dd>
    1804. 

  1804. <dt>&lsquo;<samp>codec_whitelist <var>list</var> (<em>input</em>)</samp>&rsquo;</dt>
    1805. 

  1805. <dd><p>&quot;,&quot; separated list of allowed decoders. By default all are allowed.
    1806. 

  1806. </p>
    1807. 

  1807. </dd>
    1808. 

  1808. <dt>&lsquo;<samp>dump_separator <var>string</var> (<em>input</em>)</samp>&rsquo;</dt>
    1809. 

  1809. <dd><p>Separator used to separate the fields printed on the command line about the
    1810. 

  1810. Stream parameters.
    1811. 

  1811. For example, to separate the fields with newlines and indentation:
    1812. 

  1812. </p><div class="example">
    1813. 

  1813. <pre class="example">ffprobe -dump_separator &quot;
    1814. 

  1814.                           &quot;  -i ~/videos/matrixbench_mpeg2.mpg
    1815. 

  1815. </pre></div>
    1816. 

  1816. 

  1817. </dd>
    1818. 

  1818. <dt>&lsquo;<samp>max_pixels <var>integer</var> (<em>decoding/encoding,video</em>)</samp>&rsquo;</dt>
    1819. 

  1819. <dd><p>Maximum number of pixels per image. This value can be used to avoid out of
    1820. 

  1820. memory failures due to large images.
    1821. 

  1821. </p>
    1822. 

  1822. </dd>
    1823. 

  1823. <dt>&lsquo;<samp>apply_cropping <var>bool</var> (<em>decoding,video</em>)</samp>&rsquo;</dt>
    1824. 

  1824. <dd><p>Enable cropping if cropping parameters are multiples of the required
    1825. 

  1825. alignment for the left and top parameters. If the alignment is not met the
    1826. 

  1826. cropping will be partially applied to maintain alignment.
    1827. 

  1827. Default is 1 (enabled).
    1828. 

  1828. Note: The required alignment depends on if <code>AV_CODEC_FLAG_UNALIGNED</code> is set and the
    1829. 

  1829. CPU. <code>AV_CODEC_FLAG_UNALIGNED</code> cannot be changed from the command line. Also hardware
    1830. 

  1830. decoders will not apply left/top Cropping.
    1831. 

  1831. </p>
    1832. 

  1832. 

  1833. </dd>
    1834. 

  1834. </dl>
    1835. 

  1835. 

  1836. 

  1837. <a name="Decoders"></a>
    1838. 

  1838. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Decoders">3 Decoders</a></h1>
    1839. 

  1839. 

  1840. <p>Decoders are configured elements in FFmpeg which allow the decoding of
    1841. 

  1841. multimedia streams.
    1842. 

  1842. </p>
    1843. 

  1843. <p>When you configure your FFmpeg build, all the supported native decoders
    1844. 

  1844. are enabled by default. Decoders requiring an external library must be enabled
    1845. 

  1845. manually via the corresponding <code>--enable-lib</code> option. You can list all
    1846. 

  1846. available decoders using the configure option <code>--list-decoders</code>.
    1847. 

  1847. </p>
    1848. 

  1848. <p>You can disable all the decoders with the configure option
    1849. 

  1849. <code>--disable-decoders</code> and selectively enable / disable single decoders
    1850. 

  1850. with the options <code>--enable-decoder=<var>DECODER</var></code> /
    1851. 

  1851. <code>--disable-decoder=<var>DECODER</var></code>.
    1852. 

  1852. </p>
    1853. 

  1853. <p>The option <code>-decoders</code> of the ff* tools will display the list of
    1854. 

  1854. enabled decoders.
    1855. 

  1855. </p>
    1856. 

  1856. 

  1857. <a name="Video-Decoders"></a>
    1858. 

  1858. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Video-Decoders">4 Video Decoders</a></h1>
    1859. 

  1859. 

  1860. <p>A description of some of the currently available video decoders
    1861. 

  1861. follows.
    1862. 

  1862. </p>
    1863. 

  1863. <a name="rawvideo"></a>
    1864. 

  1864. <h2 class="section"><a href="ffmpeg-codecs.html#toc-rawvideo">4.1 rawvideo</a></h2>
    1865. 

  1865. 

  1866. <p>Raw video decoder.
    1867. 

  1867. </p>
    1868. 

  1868. <p>This decoder decodes rawvideo streams.
    1869. 

  1869. </p>
    1870. 

  1870. <a name="Options-1"></a>
    1871. 

  1871. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-1">4.1.1 Options</a></h3>
    1872. 

  1872. 

  1873. <dl compact="compact">
    1874. 

  1874. <dt>&lsquo;<samp>top <var>top_field_first</var></samp>&rsquo;</dt>
    1875. 

  1875. <dd><p>Specify the assumed field type of the input video.
    1876. 

  1876. </p><dl compact="compact">
    1877. 

  1877. <dt>&lsquo;<samp>-1</samp>&rsquo;</dt>
    1878. 

  1878. <dd><p>the video is assumed to be progressive (default)
    1879. 

  1879. </p></dd>
    1880. 

  1880. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    1881. 

  1881. <dd><p>bottom-field-first is assumed
    1882. 

  1882. </p></dd>
    1883. 

  1883. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    1884. 

  1884. <dd><p>top-field-first is assumed
    1885. 

  1885. </p></dd>
    1886. 

  1886. </dl>
    1887. 

  1887. 

  1888. </dd>
    1889. 

  1889. </dl>
    1890. 

  1890. 

  1891. <a name="libdav1d"></a>
    1892. 

  1892. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libdav1d">4.2 libdav1d</a></h2>
    1893. 

  1893. 

  1894. <p>dav1d AV1 decoder.
    1895. 

  1895. </p>
    1896. 

  1896. <p>libdav1d allows libavcodec to decode the AOMedia Video 1 (AV1) codec.
    1897. 

  1897. Requires the presence of the libdav1d headers and library during configuration.
    1898. 

  1898. You need to explicitly configure the build with <code>--enable-libdav1d</code>.
    1899. 

  1899. </p>
    1900. 

  1900. <a name="Options-8"></a>
    1901. 

  1901. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-8">4.2.1 Options</a></h3>
    1902. 

  1902. 

  1903. <p>The following options are supported by the libdav1d wrapper.
    1904. 

  1904. </p>
    1905. 

  1905. <dl compact="compact">
    1906. 

  1906. <dt>&lsquo;<samp>framethreads</samp>&rsquo;</dt>
    1907. 

  1907. <dd><p>Set amount of frame threads to use during decoding. The default value is 0 (autodetect).
    1908. 

  1908. </p>
    1909. 

  1909. </dd>
    1910. 

  1910. <dt>&lsquo;<samp>tilethreads</samp>&rsquo;</dt>
    1911. 

  1911. <dd><p>Set amount of tile threads to use during decoding. The default value is 0 (autodetect).
    1912. 

  1912. </p>
    1913. 

  1913. </dd>
    1914. 

  1914. <dt>&lsquo;<samp>filmgrain</samp>&rsquo;</dt>
    1915. 

  1915. <dd><p>Apply film grain to the decoded video if present in the bitstream. Defaults to the
    1916. 

  1916. internal default of the library.
    1917. 

  1917. </p>
    1918. 

  1918. </dd>
    1919. 

  1919. <dt>&lsquo;<samp>oppoint</samp>&rsquo;</dt>
    1920. 

  1920. <dd><p>Select an operating point of a scalable AV1 bitstream (0 - 31). Defaults to the
    1921. 

  1921. internal default of the library.
    1922. 

  1922. </p>
    1923. 

  1923. </dd>
    1924. 

  1924. <dt>&lsquo;<samp>alllayers</samp>&rsquo;</dt>
    1925. 

  1925. <dd><p>Output all spatial layers of a scalable AV1 bitstream. The default value is false.
    1926. 

  1926. </p>
    1927. 

  1927. </dd>
    1928. 

  1928. </dl>
    1929. 

  1929. 

  1930. <a name="libdavs2"></a>
    1931. 

  1931. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libdavs2">4.3 libdavs2</a></h2>
    1932. 

  1932. 

  1933. <p>AVS2-P2/IEEE1857.4 video decoder wrapper.
    1934. 

  1934. </p>
    1935. 

  1935. <p>This decoder allows libavcodec to decode AVS2 streams with davs2 library.
    1936. 

  1936. </p>
    1937. 

  1937. 

  1938. <a name="Audio-Decoders"></a>
    1939. 

  1939. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Audio-Decoders">5 Audio Decoders</a></h1>
    1940. 

  1940. 

  1941. <p>A description of some of the currently available audio decoders
    1942. 

  1942. follows.
    1943. 

  1943. </p>
    1944. 

  1944. <a name="ac3"></a>
    1945. 

  1945. <h2 class="section"><a href="ffmpeg-codecs.html#toc-ac3">5.1 ac3</a></h2>
    1946. 

  1946. 

  1947. <p>AC-3 audio decoder.
    1948. 

  1948. </p>
    1949. 

  1949. <p>This decoder implements part of ATSC A/52:2010 and ETSI TS 102 366, as well as
    1950. 

  1950. the undocumented RealAudio 3 (a.k.a. dnet).
    1951. 

  1951. </p>
    1952. 

  1952. <a name="AC_002d3-Decoder-Options"></a>
    1953. 

  1953. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-AC_002d3-Decoder-Options">5.1.1 AC-3 Decoder Options</a></h3>
    1954. 

  1954. 

  1955. <dl compact="compact">
    1956. 

  1956. <dt>&lsquo;<samp>-drc_scale <var>value</var></samp>&rsquo;</dt>
    1957. 

  1957. <dd><p>Dynamic Range Scale Factor. The factor to apply to dynamic range values
    1958. 

  1958. from the AC-3 stream. This factor is applied exponentially.
    1959. 

  1959. There are 3 notable scale factor ranges:
    1960. 

  1960. </p><dl compact="compact">
    1961. 

  1961. <dt>&lsquo;<samp>drc_scale == 0</samp>&rsquo;</dt>
    1962. 

  1962. <dd><p>DRC disabled. Produces full range audio.
    1963. 

  1963. </p></dd>
    1964. 

  1964. <dt>&lsquo;<samp>0 &lt; drc_scale &lt;= 1</samp>&rsquo;</dt>
    1965. 

  1965. <dd><p>DRC enabled.  Applies a fraction of the stream DRC value.
    1966. 

  1966. Audio reproduction is between full range and full compression.
    1967. 

  1967. </p></dd>
    1968. 

  1968. <dt>&lsquo;<samp>drc_scale &gt; 1</samp>&rsquo;</dt>
    1969. 

  1969. <dd><p>DRC enabled. Applies drc_scale asymmetrically.
    1970. 

  1970. Loud sounds are fully compressed.  Soft sounds are enhanced.
    1971. 

  1971. </p></dd>
    1972. 

  1972. </dl>
    1973. 

  1973. 

  1974. </dd>
    1975. 

  1975. </dl>
    1976. 

  1976. 

  1977. <a name="flac-1"></a>
    1978. 

  1978. <h2 class="section"><a href="ffmpeg-codecs.html#toc-flac-1">5.2 flac</a></h2>
    1979. 

  1979. 

  1980. <p>FLAC audio decoder.
    1981. 

  1981. </p>
    1982. 

  1982. <p>This decoder aims to implement the complete FLAC specification from Xiph.
    1983. 

  1983. </p>
    1984. 

  1984. <a name="FLAC-Decoder-options"></a>
    1985. 

  1985. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-FLAC-Decoder-options">5.2.1 FLAC Decoder options</a></h3>
    1986. 

  1986. 

  1987. <dl compact="compact">
    1988. 

  1988. <dt>&lsquo;<samp>-use_buggy_lpc</samp>&rsquo;</dt>
    1989. 

  1989. <dd><p>The lavc FLAC encoder used to produce buggy streams with high lpc values
    1990. 

  1990. (like the default value). This option makes it possible to decode such streams
    1991. 

  1991. correctly by using lavc&rsquo;s old buggy lpc logic for decoding.
    1992. 

  1992. </p>
    1993. 

  1993. </dd>
    1994. 

  1994. </dl>
    1995. 

  1995. 

  1996. <a name="ffwavesynth"></a>
    1997. 

  1997. <h2 class="section"><a href="ffmpeg-codecs.html#toc-ffwavesynth">5.3 ffwavesynth</a></h2>
    1998. 

  1998. 

  1999. <p>Internal wave synthesizer.
    2000. 

  2000. </p>
    2001. 

  2001. <p>This decoder generates wave patterns according to predefined sequences. Its
    2002. 

  2002. use is purely internal and the format of the data it accepts is not publicly
    2003. 

  2003. documented.
    2004. 

  2004. </p>
    2005. 

  2005. <a name="libcelt"></a>
    2006. 

  2006. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libcelt">5.4 libcelt</a></h2>
    2007. 

  2007. 

  2008. <p>libcelt decoder wrapper.
    2009. 

  2009. </p>
    2010. 

  2010. <p>libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio codec.
    2011. 

  2011. Requires the presence of the libcelt headers and library during configuration.
    2012. 

  2012. You need to explicitly configure the build with <code>--enable-libcelt</code>.
    2013. 

  2013. </p>
    2014. 

  2014. <a name="libgsm"></a>
    2015. 

  2015. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libgsm">5.5 libgsm</a></h2>
    2016. 

  2016. 

  2017. <p>libgsm decoder wrapper.
    2018. 

  2018. </p>
    2019. 

  2019. <p>libgsm allows libavcodec to decode the GSM full rate audio codec. Requires
    2020. 

  2020. the presence of the libgsm headers and library during configuration. You need
    2021. 

  2021. to explicitly configure the build with <code>--enable-libgsm</code>.
    2022. 

  2022. </p>
    2023. 

  2023. <p>This decoder supports both the ordinary GSM and the Microsoft variant.
    2024. 

  2024. </p>
    2025. 

  2025. <a name="libilbc"></a>
    2026. 

  2026. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libilbc">5.6 libilbc</a></h2>
    2027. 

  2027. 

  2028. <p>libilbc decoder wrapper.
    2029. 

  2029. </p>
    2030. 

  2030. <p>libilbc allows libavcodec to decode the Internet Low Bitrate Codec (iLBC)
    2031. 

  2031. audio codec. Requires the presence of the libilbc headers and library during
    2032. 

  2032. configuration. You need to explicitly configure the build with
    2033. 

  2033. <code>--enable-libilbc</code>.
    2034. 

  2034. </p>
    2035. 

  2035. <a name="Options-33"></a>
    2036. 

  2036. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-33">5.6.1 Options</a></h3>
    2037. 

  2037. 

  2038. <p>The following option is supported by the libilbc wrapper.
    2039. 

  2039. </p>
    2040. 

  2040. <dl compact="compact">
    2041. 

  2041. <dt>&lsquo;<samp>enhance</samp>&rsquo;</dt>
    2042. 

  2042. <dd>
    2043. 

  2043. <p>Enable the enhancement of the decoded audio when set to 1. The default
    2044. 

  2044. value is 0 (disabled).
    2045. 

  2045. </p>
    2046. 

  2046. </dd>
    2047. 

  2047. </dl>
    2048. 

  2048. 

  2049. <a name="libopencore_002damrnb"></a>
    2050. 

  2050. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libopencore_002damrnb">5.7 libopencore-amrnb</a></h2>
    2051. 

  2051. 

  2052. <p>libopencore-amrnb decoder wrapper.
    2053. 

  2053. </p>
    2054. 

  2054. <p>libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate
    2055. 

  2055. Narrowband audio codec. Using it requires the presence of the
    2056. 

  2056. libopencore-amrnb headers and library during configuration. You need to
    2057. 

  2057. explicitly configure the build with <code>--enable-libopencore-amrnb</code>.
    2058. 

  2058. </p>
    2059. 

  2059. <p>An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB
    2060. 

  2060. without this library.
    2061. 

  2061. </p>
    2062. 

  2062. <a name="libopencore_002damrwb"></a>
    2063. 

  2063. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libopencore_002damrwb">5.8 libopencore-amrwb</a></h2>
    2064. 

  2064. 

  2065. <p>libopencore-amrwb decoder wrapper.
    2066. 

  2066. </p>
    2067. 

  2067. <p>libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate
    2068. 

  2068. Wideband audio codec. Using it requires the presence of the
    2069. 

  2069. libopencore-amrwb headers and library during configuration. You need to
    2070. 

  2070. explicitly configure the build with <code>--enable-libopencore-amrwb</code>.
    2071. 

  2071. </p>
    2072. 

  2072. <p>An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB
    2073. 

  2073. without this library.
    2074. 

  2074. </p>
    2075. 

  2075. <a name="libopus-1"></a>
    2076. 

  2076. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libopus-1">5.9 libopus</a></h2>
    2077. 

  2077. 

  2078. <p>libopus decoder wrapper.
    2079. 

  2079. </p>
    2080. 

  2080. <p>libopus allows libavcodec to decode the Opus Interactive Audio Codec.
    2081. 

  2081. Requires the presence of the libopus headers and library during
    2082. 

  2082. configuration. You need to explicitly configure the build with
    2083. 

  2083. <code>--enable-libopus</code>.
    2084. 

  2084. </p>
    2085. 

  2085. <p>An FFmpeg native decoder for Opus exists, so users can decode Opus
    2086. 

  2086. without this library.
    2087. 

  2087. </p>
    2088. 

  2088. 

  2089. <a name="Subtitles-Decoders"></a>
    2090. 

  2090. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Subtitles-Decoders">6 Subtitles Decoders</a></h1>
    2091. 

  2091. 

  2092. <a name="libaribb24"></a>
    2093. 

  2093. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libaribb24">6.1 libaribb24</a></h2>
    2094. 

  2094. 

  2095. <p>ARIB STD-B24 caption decoder.
    2096. 

  2096. </p>
    2097. 

  2097. <p>Implements profiles A and C of the ARIB STD-B24 standard.
    2098. 

  2098. </p>
    2099. 

  2099. <a name="libaribb24-Decoder-Options"></a>
    2100. 

  2100. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-libaribb24-Decoder-Options">6.1.1 libaribb24 Decoder Options</a></h3>
    2101. 

  2101. 

  2102. <dl compact="compact">
    2103. 

  2103. <dt>&lsquo;<samp>-aribb24-base-path <var>path</var></samp>&rsquo;</dt>
    2104. 

  2104. <dd><p>Sets the base path for the libaribb24 library. This is utilized for reading of
    2105. 

  2105. configuration files (for custom unicode conversions), and for dumping of
    2106. 

  2106. non-text symbols as images under that location.
    2107. 

  2107. </p>
    2108. 

  2108. <p>Unset by default.
    2109. 

  2109. </p>
    2110. 

  2110. </dd>
    2111. 

  2111. <dt>&lsquo;<samp>-aribb24-skip-ruby-text <var>boolean</var></samp>&rsquo;</dt>
    2112. 

  2112. <dd><p>Tells the decoder wrapper to skip text blocks that contain half-height ruby
    2113. 

  2113. text.
    2114. 

  2114. </p>
    2115. 

  2115. <p>Enabled by default.
    2116. 

  2116. </p>
    2117. 

  2117. </dd>
    2118. 

  2118. </dl>
    2119. 

  2119. 

  2120. <a name="dvbsub"></a>
    2121. 

  2121. <h2 class="section"><a href="ffmpeg-codecs.html#toc-dvbsub">6.2 dvbsub</a></h2>
    2122. 

  2122. 

  2123. <a name="Options-10"></a>
    2124. 

  2124. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-10">6.2.1 Options</a></h3>
    2125. 

  2125. 

  2126. <dl compact="compact">
    2127. 

  2127. <dt>&lsquo;<samp>compute_clut</samp>&rsquo;</dt>
    2128. 

  2128. <dd><dl compact="compact">
    2129. 

  2129. <dt>&lsquo;<samp>-1</samp>&rsquo;</dt>
    2130. 

  2130. <dd><p>Compute clut if no matching CLUT is in the stream.
    2131. 

  2131. </p></dd>
    2132. 

  2132. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2133. 

  2133. <dd><p>Never compute CLUT
    2134. 

  2134. </p></dd>
    2135. 

  2135. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2136. 

  2136. <dd><p>Always compute CLUT and override the one provided in the stream.
    2137. 

  2137. </p></dd>
    2138. 

  2138. </dl>
    2139. 

  2139. </dd>
    2140. 

  2140. <dt>&lsquo;<samp>dvb_substream</samp>&rsquo;</dt>
    2141. 

  2141. <dd><p>Selects the dvb substream, or all substreams if -1 which is default.
    2142. 

  2142. </p>
    2143. 

  2143. </dd>
    2144. 

  2144. </dl>
    2145. 

  2145. 

  2146. <a name="dvdsub"></a>
    2147. 

  2147. <h2 class="section"><a href="ffmpeg-codecs.html#toc-dvdsub">6.3 dvdsub</a></h2>
    2148. 

  2148. 

  2149. <p>This codec decodes the bitmap subtitles used in DVDs; the same subtitles can
    2150. 

  2150. also be found in VobSub file pairs and in some Matroska files.
    2151. 

  2151. </p>
    2152. 

  2152. <a name="Options-3"></a>
    2153. 

  2153. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-3">6.3.1 Options</a></h3>
    2154. 

  2154. 

  2155. <dl compact="compact">
    2156. 

  2156. <dt>&lsquo;<samp>palette</samp>&rsquo;</dt>
    2157. 

  2157. <dd><p>Specify the global palette used by the bitmaps. When stored in VobSub, the
    2158. 

  2158. palette is normally specified in the index file; in Matroska, the palette is
    2159. 

  2159. stored in the codec extra-data in the same format as in VobSub. In DVDs, the
    2160. 

  2160. palette is stored in the IFO file, and therefore not available when reading
    2161. 

  2161. from dumped VOB files.
    2162. 

  2162. </p>
    2163. 

  2163. <p>The format for this option is a string containing 16 24-bits hexadecimal
    2164. 

  2164. numbers (without 0x prefix) separated by commas, for example <code>0d00ee,
    2165. 

  2165. ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,
    2166. 

  2166. 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b</code>.
    2167. 

  2167. </p>
    2168. 

  2168. </dd>
    2169. 

  2169. <dt>&lsquo;<samp>ifo_palette</samp>&rsquo;</dt>
    2170. 

  2170. <dd><p>Specify the IFO file from which the global palette is obtained.
    2171. 

  2171. (experimental)
    2172. 

  2172. </p>
    2173. 

  2173. </dd>
    2174. 

  2174. <dt>&lsquo;<samp>forced_subs_only</samp>&rsquo;</dt>
    2175. 

  2175. <dd><p>Only decode subtitle entries marked as forced. Some titles have forced
    2176. 

  2176. and non-forced subtitles in the same track. Setting this flag to <code>1</code>
    2177. 

  2177. will only keep the forced subtitles. Default value is <code>0</code>.
    2178. 

  2178. </p></dd>
    2179. 

  2179. </dl>
    2180. 

  2180. 

  2181. <a name="libzvbi_002dteletext"></a>
    2182. 

  2182. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libzvbi_002dteletext">6.4 libzvbi-teletext</a></h2>
    2183. 

  2183. 

  2184. <p>Libzvbi allows libavcodec to decode DVB teletext pages and DVB teletext
    2185. 

  2185. subtitles. Requires the presence of the libzvbi headers and library during
    2186. 

  2186. configuration. You need to explicitly configure the build with
    2187. 

  2187. <code>--enable-libzvbi</code>.
    2188. 

  2188. </p>
    2189. 

  2189. <a name="Options-29"></a>
    2190. 

  2190. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-29">6.4.1 Options</a></h3>
    2191. 

  2191. 

  2192. <dl compact="compact">
    2193. 

  2193. <dt>&lsquo;<samp>txt_page</samp>&rsquo;</dt>
    2194. 

  2194. <dd><p>List of teletext page numbers to decode. Pages that do not match the specified
    2195. 

  2195. list are dropped. You may use the special <code>*</code> string to match all pages,
    2196. 

  2196. or <code>subtitle</code> to match all subtitle pages.
    2197. 

  2197. Default value is *.
    2198. 

  2198. </p></dd>
    2199. 

  2199. <dt>&lsquo;<samp>txt_default_region</samp>&rsquo;</dt>
    2200. 

  2200. <dd><p>Set default G0 character set used for decoding, a value between 0 and 80 (see
    2201. 

  2201. ETS 300 706, Section 15, Table 32). Default value is -1, which does not
    2202. 

  2202. override the libzvbi default. This option is needed for some legacy level 1.0
    2203. 

  2203. transmissions which cannot signal the proper charset.
    2204. 

  2204. </p></dd>
    2205. 

  2205. <dt>&lsquo;<samp>txt_chop_top</samp>&rsquo;</dt>
    2206. 

  2206. <dd><p>Discards the top teletext line. Default value is 1.
    2207. 

  2207. </p></dd>
    2208. 

  2208. <dt>&lsquo;<samp>txt_format</samp>&rsquo;</dt>
    2209. 

  2209. <dd><p>Specifies the format of the decoded subtitles.
    2210. 

  2210. </p><dl compact="compact">
    2211. 

  2211. <dt>&lsquo;<samp>bitmap</samp>&rsquo;</dt>
    2212. 

  2212. <dd><p>The default format, you should use this for teletext pages, because certain
    2213. 

  2213. graphics and colors cannot be expressed in simple text or even ASS.
    2214. 

  2214. </p></dd>
    2215. 

  2215. <dt>&lsquo;<samp>text</samp>&rsquo;</dt>
    2216. 

  2216. <dd><p>Simple text based output without formatting.
    2217. 

  2217. </p></dd>
    2218. 

  2218. <dt>&lsquo;<samp>ass</samp>&rsquo;</dt>
    2219. 

  2219. <dd><p>Formatted ASS output, subtitle pages and teletext pages are returned in
    2220. 

  2220. different styles, subtitle pages are stripped down to text, but an effort is
    2221. 

  2221. made to keep the text alignment and the formatting.
    2222. 

  2222. </p></dd>
    2223. 

  2223. </dl>
    2224. 

  2224. </dd>
    2225. 

  2225. <dt>&lsquo;<samp>txt_left</samp>&rsquo;</dt>
    2226. 

  2226. <dd><p>X offset of generated bitmaps, default is 0.
    2227. 

  2227. </p></dd>
    2228. 

  2228. <dt>&lsquo;<samp>txt_top</samp>&rsquo;</dt>
    2229. 

  2229. <dd><p>Y offset of generated bitmaps, default is 0.
    2230. 

  2230. </p></dd>
    2231. 

  2231. <dt>&lsquo;<samp>txt_chop_spaces</samp>&rsquo;</dt>
    2232. 

  2232. <dd><p>Chops leading and trailing spaces and removes empty lines from the generated
    2233. 

  2233. text. This option is useful for teletext based subtitles where empty spaces may
    2234. 

  2234. be present at the start or at the end of the lines or empty lines may be
    2235. 

  2235. present between the subtitle lines because of double-sized teletext characters.
    2236. 

  2236. Default value is 1.
    2237. 

  2237. </p></dd>
    2238. 

  2238. <dt>&lsquo;<samp>txt_duration</samp>&rsquo;</dt>
    2239. 

  2239. <dd><p>Sets the display duration of the decoded teletext pages or subtitles in
    2240. 

  2240. milliseconds. Default value is -1 which means infinity or until the next
    2241. 

  2241. subtitle event comes.
    2242. 

  2242. </p></dd>
    2243. 

  2243. <dt>&lsquo;<samp>txt_transparent</samp>&rsquo;</dt>
    2244. 

  2244. <dd><p>Force transparent background of the generated teletext bitmaps. Default value
    2245. 

  2245. is 0 which means an opaque background.
    2246. 

  2246. </p></dd>
    2247. 

  2247. <dt>&lsquo;<samp>txt_opacity</samp>&rsquo;</dt>
    2248. 

  2248. <dd><p>Sets the opacity (0-255) of the teletext background. If
    2249. 

  2249. &lsquo;<samp>txt_transparent</samp>&rsquo; is not set, it only affects characters between a start
    2250. 

  2250. box and an end box, typically subtitles. Default value is 0 if
    2251. 

  2251. &lsquo;<samp>txt_transparent</samp>&rsquo; is set, 255 otherwise.
    2252. 

  2252. </p>
    2253. 

  2253. </dd>
    2254. 

  2254. </dl>
    2255. 

  2255. 

  2256. <a name="Encoders"></a>
    2257. 

  2257. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Encoders">7 Encoders</a></h1>
    2258. 

  2258. 

  2259. <p>Encoders are configured elements in FFmpeg which allow the encoding of
    2260. 

  2260. multimedia streams.
    2261. 

  2261. </p>
    2262. 

  2262. <p>When you configure your FFmpeg build, all the supported native encoders
    2263. 

  2263. are enabled by default. Encoders requiring an external library must be enabled
    2264. 

  2264. manually via the corresponding <code>--enable-lib</code> option. You can list all
    2265. 

  2265. available encoders using the configure option <code>--list-encoders</code>.
    2266. 

  2266. </p>
    2267. 

  2267. <p>You can disable all the encoders with the configure option
    2268. 

  2268. <code>--disable-encoders</code> and selectively enable / disable single encoders
    2269. 

  2269. with the options <code>--enable-encoder=<var>ENCODER</var></code> /
    2270. 

  2270. <code>--disable-encoder=<var>ENCODER</var></code>.
    2271. 

  2271. </p>
    2272. 

  2272. <p>The option <code>-encoders</code> of the ff* tools will display the list of
    2273. 

  2273. enabled encoders.
    2274. 

  2274. </p>
    2275. 

  2275. 

  2276. <a name="Audio-Encoders"></a>
    2277. 

  2277. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Audio-Encoders">8 Audio Encoders</a></h1>
    2278. 

  2278. 

  2279. <p>A description of some of the currently available audio encoders
    2280. 

  2280. follows.
    2281. 

  2281. </p>
    2282. 

  2282. <p><a name="aacenc"></a>
    2283. 

  2283. </p><a name="aac"></a>
    2284. 

  2284. <h2 class="section"><a href="ffmpeg-codecs.html#toc-aac">8.1 aac</a></h2>
    2285. 

  2285. 

  2286. <p>Advanced Audio Coding (AAC) encoder.
    2287. 

  2287. </p>
    2288. 

  2288. <p>This encoder is the default AAC encoder, natively implemented into FFmpeg.
    2289. 

  2289. </p>
    2290. 

  2290. <a name="Options-12"></a>
    2291. 

  2291. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-12">8.1.1 Options</a></h3>
    2292. 

  2292. 

  2293. <dl compact="compact">
    2294. 

  2294. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    2295. 

  2295. <dd><p>Set bit rate in bits/s. Setting this automatically activates constant bit rate
    2296. 

  2296. (CBR) mode. If this option is unspecified it is set to 128kbps.
    2297. 

  2297. </p>
    2298. 

  2298. </dd>
    2299. 

  2299. <dt>&lsquo;<samp>q</samp>&rsquo;</dt>
    2300. 

  2300. <dd><p>Set quality for variable bit rate (VBR) mode. This option is valid only using
    2301. 

  2301. the <code>ffmpeg</code> command-line tool. For library interface users, use
    2302. 

  2302. &lsquo;<samp>global_quality</samp>&rsquo;.
    2303. 

  2303. </p>
    2304. 

  2304. </dd>
    2305. 

  2305. <dt>&lsquo;<samp>cutoff</samp>&rsquo;</dt>
    2306. 

  2306. <dd><p>Set cutoff frequency. If unspecified will allow the encoder to dynamically
    2307. 

  2307. adjust the cutoff to improve clarity on low bitrates.
    2308. 

  2308. </p>
    2309. 

  2309. </dd>
    2310. 

  2310. <dt>&lsquo;<samp>aac_coder</samp>&rsquo;</dt>
    2311. 

  2311. <dd><p>Set AAC encoder coding method. Possible values:
    2312. 

  2312. </p>
    2313. 

  2313. <dl compact="compact">
    2314. 

  2314. <dt>&lsquo;<samp>twoloop</samp>&rsquo;</dt>
    2315. 

  2315. <dd><p>Two loop searching (TLS) method.
    2316. 

  2316. </p>
    2317. 

  2317. <p>This method first sets quantizers depending on band thresholds and then tries
    2318. 

  2318. to find an optimal combination by adding or subtracting a specific value from
    2319. 

  2319. all quantizers and adjusting some individual quantizer a little.  Will tune
    2320. 

  2320. itself based on whether &lsquo;<samp>aac_is</samp>&rsquo;, &lsquo;<samp>aac_ms</samp>&rsquo; and &lsquo;<samp>aac_pns</samp>&rsquo;
    2321. 

  2321. are enabled.
    2322. 

  2322. </p>
    2323. 

  2323. </dd>
    2324. 

  2324. <dt>&lsquo;<samp>anmr</samp>&rsquo;</dt>
    2325. 

  2325. <dd><p>Average noise to mask ratio (ANMR) trellis-based solution.
    2326. 

  2326. </p>
    2327. 

  2327. <p>This is an experimental coder which currently produces a lower quality, is more
    2328. 

  2328. unstable and is slower than the default twoloop coder but has potential.
    2329. 

  2329. Currently has no support for the &lsquo;<samp>aac_is</samp>&rsquo; or &lsquo;<samp>aac_pns</samp>&rsquo; options.
    2330. 

  2330. Not currently recommended.
    2331. 

  2331. </p>
    2332. 

  2332. </dd>
    2333. 

  2333. <dt>&lsquo;<samp>fast</samp>&rsquo;</dt>
    2334. 

  2334. <dd><p>Constant quantizer method.
    2335. 

  2335. </p>
    2336. 

  2336. <p>Uses a cheaper version of twoloop algorithm that doesn&rsquo;t try to do as many
    2337. 

  2337. clever adjustments. Worse with low bitrates (less than 64kbps), but is better
    2338. 

  2338. and much faster at higher bitrates.
    2339. 

  2339. This is the default choice for a coder
    2340. 

  2340. </p>
    2341. 

  2341. </dd>
    2342. 

  2342. </dl>
    2343. 

  2343. 

  2344. </dd>
    2345. 

  2345. <dt>&lsquo;<samp>aac_ms</samp>&rsquo;</dt>
    2346. 

  2346. <dd><p>Sets mid/side coding mode. The default value of &quot;auto&quot; will automatically use
    2347. 

  2347. M/S with bands which will benefit from such coding. Can be forced for all bands
    2348. 

  2348. using the value &quot;enable&quot;, which is mainly useful for debugging or disabled using
    2349. 

  2349. &quot;disable&quot;.
    2350. 

  2350. </p>
    2351. 

  2351. </dd>
    2352. 

  2352. <dt>&lsquo;<samp>aac_is</samp>&rsquo;</dt>
    2353. 

  2353. <dd><p>Sets intensity stereo coding tool usage. By default, it&rsquo;s enabled and will
    2354. 

  2354. automatically toggle IS for similar pairs of stereo bands if it&rsquo;s beneficial.
    2355. 

  2355. Can be disabled for debugging by setting the value to &quot;disable&quot;.
    2356. 

  2356. </p>
    2357. 

  2357. </dd>
    2358. 

  2358. <dt>&lsquo;<samp>aac_pns</samp>&rsquo;</dt>
    2359. 

  2359. <dd><p>Uses perceptual noise substitution to replace low entropy high frequency bands
    2360. 

  2360. with imperceptible white noise during the decoding process. By default, it&rsquo;s
    2361. 

  2361. enabled, but can be disabled for debugging purposes by using &quot;disable&quot;.
    2362. 

  2362. </p>
    2363. 

  2363. </dd>
    2364. 

  2364. <dt>&lsquo;<samp>aac_tns</samp>&rsquo;</dt>
    2365. 

  2365. <dd><p>Enables the use of a multitap FIR filter which spans through the high frequency
    2366. 

  2366. bands to hide quantization noise during the encoding process and is reverted
    2367. 

  2367. by the decoder. As well as decreasing unpleasant artifacts in the high range
    2368. 

  2368. this also reduces the entropy in the high bands and allows for more bits to
    2369. 

  2369. be used by the mid-low bands. By default it&rsquo;s enabled but can be disabled for
    2370. 

  2370. debugging by setting the option to &quot;disable&quot;.
    2371. 

  2371. </p>
    2372. 

  2372. </dd>
    2373. 

  2373. <dt>&lsquo;<samp>aac_ltp</samp>&rsquo;</dt>
    2374. 

  2374. <dd><p>Enables the use of the long term prediction extension which increases coding
    2375. 

  2375. efficiency in very low bandwidth situations such as encoding of voice or
    2376. 

  2376. solo piano music by extending constant harmonic peaks in bands throughout
    2377. 

  2377. frames. This option is implied by profile:a aac_low and is incompatible with
    2378. 

  2378. aac_pred. Use in conjunction with &lsquo;<samp>-ar</samp>&rsquo; to decrease the samplerate.
    2379. 

  2379. </p>
    2380. 

  2380. </dd>
    2381. 

  2381. <dt>&lsquo;<samp>aac_pred</samp>&rsquo;</dt>
    2382. 

  2382. <dd><p>Enables the use of a more traditional style of prediction where the spectral
    2383. 

  2383. coefficients transmitted are replaced by the difference of the current
    2384. 

  2384. coefficients minus the previous &quot;predicted&quot; coefficients. In theory and sometimes
    2385. 

  2385. in practice this can improve quality for low to mid bitrate audio.
    2386. 

  2386. This option implies the aac_main profile and is incompatible with aac_ltp.
    2387. 

  2387. </p>
    2388. 

  2388. </dd>
    2389. 

  2389. <dt>&lsquo;<samp>profile</samp>&rsquo;</dt>
    2390. 

  2390. <dd><p>Sets the encoding profile, possible values:
    2391. 

  2391. </p>
    2392. 

  2392. <dl compact="compact">
    2393. 

  2393. <dt>&lsquo;<samp>aac_low</samp>&rsquo;</dt>
    2394. 

  2394. <dd><p>The default, AAC &quot;Low-complexity&quot; profile. Is the most compatible and produces
    2395. 

  2395. decent quality.
    2396. 

  2396. </p>
    2397. 

  2397. </dd>
    2398. 

  2398. <dt>&lsquo;<samp>mpeg2_aac_low</samp>&rsquo;</dt>
    2399. 

  2399. <dd><p>Equivalent to <code>-profile:a aac_low -aac_pns 0</code>. PNS was introduced with the
    2400. 

  2400. MPEG4 specifications.
    2401. 

  2401. </p>
    2402. 

  2402. </dd>
    2403. 

  2403. <dt>&lsquo;<samp>aac_ltp</samp>&rsquo;</dt>
    2404. 

  2404. <dd><p>Long term prediction profile, is enabled by and will enable the &lsquo;<samp>aac_ltp</samp>&rsquo;
    2405. 

  2405. option. Introduced in MPEG4.
    2406. 

  2406. </p>
    2407. 

  2407. </dd>
    2408. 

  2408. <dt>&lsquo;<samp>aac_main</samp>&rsquo;</dt>
    2409. 

  2409. <dd><p>Main-type prediction profile, is enabled by and will enable the &lsquo;<samp>aac_pred</samp>&rsquo;
    2410. 

  2410. option. Introduced in MPEG2.
    2411. 

  2411. </p>
    2412. 

  2412. </dd>
    2413. 

  2413. </dl>
    2414. 

  2414. <p>If this option is unspecified it is set to &lsquo;<samp>aac_low</samp>&rsquo;.
    2415. 

  2415. </p></dd>
    2416. 

  2416. </dl>
    2417. 

  2417. 

  2418. <a name="ac3-and-ac3_005ffixed"></a>
    2419. 

  2419. <h2 class="section"><a href="ffmpeg-codecs.html#toc-ac3-and-ac3_005ffixed">8.2 ac3 and ac3_fixed</a></h2>
    2420. 

  2420. 

  2421. <p>AC-3 audio encoders.
    2422. 

  2422. </p>
    2423. 

  2423. <p>These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
    2424. 

  2424. the undocumented RealAudio 3 (a.k.a. dnet).
    2425. 

  2425. </p>
    2426. 

  2426. <p>The <var>ac3</var> encoder uses floating-point math, while the <var>ac3_fixed</var>
    2427. 

  2427. encoder only uses fixed-point integer math. This does not mean that one is
    2428. 

  2428. always faster, just that one or the other may be better suited to a
    2429. 

  2429. particular system. The floating-point encoder will generally produce better
    2430. 

  2430. quality audio for a given bitrate. The <var>ac3_fixed</var> encoder is not the
    2431. 

  2431. default codec for any of the output formats, so it must be specified explicitly
    2432. 

  2432. using the option <code>-acodec ac3_fixed</code> in order to use it.
    2433. 

  2433. </p>
    2434. 

  2434. <a name="AC_002d3-Metadata"></a>
    2435. 

  2435. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-AC_002d3-Metadata">8.2.1 AC-3 Metadata</a></h3>
    2436. 

  2436. 

  2437. <p>The AC-3 metadata options are used to set parameters that describe the audio,
    2438. 

  2438. but in most cases do not affect the audio encoding itself. Some of the options
    2439. 

  2439. do directly affect or influence the decoding and playback of the resulting
    2440. 

  2440. bitstream, while others are just for informational purposes. A few of the
    2441. 

  2441. options will add bits to the output stream that could otherwise be used for
    2442. 

  2442. audio data, and will thus affect the quality of the output. Those will be
    2443. 

  2443. indicated accordingly with a note in the option list below.
    2444. 

  2444. </p>
    2445. 

  2445. <p>These parameters are described in detail in several publicly-available
    2446. 

  2446. documents.
    2447. 

  2447. </p><ul>
    2448. 

  2448. <li> <a href="http://www.atsc.org/cms/standards/a_52-2010.pdf">A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard</a>
    2449. 

  2449. </li><li> <a href="http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf">A/54 - Guide to the Use of the ATSC Digital Television Standard</a>
    2450. 

  2450. </li><li> <a href="http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf">Dolby Metadata Guide</a>
    2451. 

  2451. </li><li> <a href="http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf">Dolby Digital Professional Encoding Guidelines</a>
    2452. 

  2452. </li></ul>
    2453. 

  2453. 

  2454. <a name="Metadata-Control-Options"></a>
    2455. 

  2455. <h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Metadata-Control-Options">8.2.1.1 Metadata Control Options</a></h4>
    2456. 

  2456. 

  2457. <dl compact="compact">
    2458. 

  2458. <dt>&lsquo;<samp>-per_frame_metadata <var>boolean</var></samp>&rsquo;</dt>
    2459. 

  2459. <dd><p>Allow Per-Frame Metadata. Specifies if the encoder should check for changing
    2460. 

  2460. metadata for each frame.
    2461. 

  2461. </p><dl compact="compact">
    2462. 

  2462. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2463. 

  2463. <dd><p>The metadata values set at initialization will be used for every frame in the
    2464. 

  2464. stream. (default)
    2465. 

  2465. </p></dd>
    2466. 

  2466. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2467. 

  2467. <dd><p>Metadata values can be changed before encoding each frame.
    2468. 

  2468. </p></dd>
    2469. 

  2469. </dl>
    2470. 

  2470. 

  2471. </dd>
    2472. 

  2472. </dl>
    2473. 

  2473. 

  2474. <a name="Downmix-Levels"></a>
    2475. 

  2475. <h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Downmix-Levels">8.2.1.2 Downmix Levels</a></h4>
    2476. 

  2476. 

  2477. <dl compact="compact">
    2478. 

  2478. <dt>&lsquo;<samp>-center_mixlev <var>level</var></samp>&rsquo;</dt>
    2479. 

  2479. <dd><p>Center Mix Level. The amount of gain the decoder should apply to the center
    2480. 

  2480. channel when downmixing to stereo. This field will only be written to the
    2481. 

  2481. bitstream if a center channel is present. The value is specified as a scale
    2482. 

  2482. factor. There are 3 valid values:
    2483. 

  2483. </p><dl compact="compact">
    2484. 

  2484. <dt>&lsquo;<samp>0.707</samp>&rsquo;</dt>
    2485. 

  2485. <dd><p>Apply -3dB gain
    2486. 

  2486. </p></dd>
    2487. 

  2487. <dt>&lsquo;<samp>0.595</samp>&rsquo;</dt>
    2488. 

  2488. <dd><p>Apply -4.5dB gain (default)
    2489. 

  2489. </p></dd>
    2490. 

  2490. <dt>&lsquo;<samp>0.500</samp>&rsquo;</dt>
    2491. 

  2491. <dd><p>Apply -6dB gain
    2492. 

  2492. </p></dd>
    2493. 

  2493. </dl>
    2494. 

  2494. 

  2495. </dd>
    2496. 

  2496. <dt>&lsquo;<samp>-surround_mixlev <var>level</var></samp>&rsquo;</dt>
    2497. 

  2497. <dd><p>Surround Mix Level. The amount of gain the decoder should apply to the surround
    2498. 

  2498. channel(s) when downmixing to stereo. This field will only be written to the
    2499. 

  2499. bitstream if one or more surround channels are present. The value is specified
    2500. 

  2500. as a scale factor.  There are 3 valid values:
    2501. 

  2501. </p><dl compact="compact">
    2502. 

  2502. <dt>&lsquo;<samp>0.707</samp>&rsquo;</dt>
    2503. 

  2503. <dd><p>Apply -3dB gain
    2504. 

  2504. </p></dd>
    2505. 

  2505. <dt>&lsquo;<samp>0.500</samp>&rsquo;</dt>
    2506. 

  2506. <dd><p>Apply -6dB gain (default)
    2507. 

  2507. </p></dd>
    2508. 

  2508. <dt>&lsquo;<samp>0.000</samp>&rsquo;</dt>
    2509. 

  2509. <dd><p>Silence Surround Channel(s)
    2510. 

  2510. </p></dd>
    2511. 

  2511. </dl>
    2512. 

  2512. 

  2513. </dd>
    2514. 

  2514. </dl>
    2515. 

  2515. 

  2516. <a name="Audio-Production-Information"></a>
    2517. 

  2517. <h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Audio-Production-Information">8.2.1.3 Audio Production Information</a></h4>
    2518. 

  2518. <p>Audio Production Information is optional information describing the mixing
    2519. 

  2519. environment.  Either none or both of the fields are written to the bitstream.
    2520. 

  2520. </p>
    2521. 

  2521. <dl compact="compact">
    2522. 

  2522. <dt>&lsquo;<samp>-mixing_level <var>number</var></samp>&rsquo;</dt>
    2523. 

  2523. <dd><p>Mixing Level. Specifies peak sound pressure level (SPL) in the production
    2524. 

  2524. environment when the mix was mastered. Valid values are 80 to 111, or -1 for
    2525. 

  2525. unknown or not indicated. The default value is -1, but that value cannot be
    2526. 

  2526. used if the Audio Production Information is written to the bitstream. Therefore,
    2527. 

  2527. if the <code>room_type</code> option is not the default value, the <code>mixing_level</code>
    2528. 

  2528. option must not be -1.
    2529. 

  2529. </p>
    2530. 

  2530. </dd>
    2531. 

  2531. <dt>&lsquo;<samp>-room_type <var>type</var></samp>&rsquo;</dt>
    2532. 

  2532. <dd><p>Room Type. Describes the equalization used during the final mixing session at
    2533. 

  2533. the studio or on the dubbing stage. A large room is a dubbing stage with the
    2534. 

  2534. industry standard X-curve equalization; a small room has flat equalization.
    2535. 

  2535. This field will not be written to the bitstream if both the <code>mixing_level</code>
    2536. 

  2536. option and the <code>room_type</code> option have the default values.
    2537. 

  2537. </p><dl compact="compact">
    2538. 

  2538. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2539. 

  2539. <dt>&lsquo;<samp>notindicated</samp>&rsquo;</dt>
    2540. 

  2540. <dd><p>Not Indicated (default)
    2541. 

  2541. </p></dd>
    2542. 

  2542. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2543. 

  2543. <dt>&lsquo;<samp>large</samp>&rsquo;</dt>
    2544. 

  2544. <dd><p>Large Room
    2545. 

  2545. </p></dd>
    2546. 

  2546. <dt>&lsquo;<samp>2</samp>&rsquo;</dt>
    2547. 

  2547. <dt>&lsquo;<samp>small</samp>&rsquo;</dt>
    2548. 

  2548. <dd><p>Small Room
    2549. 

  2549. </p></dd>
    2550. 

  2550. </dl>
    2551. 

  2551. 

  2552. </dd>
    2553. 

  2553. </dl>
    2554. 

  2554. 

  2555. <a name="Other-Metadata-Options"></a>
    2556. 

  2556. <h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Other-Metadata-Options">8.2.1.4 Other Metadata Options</a></h4>
    2557. 

  2557. 

  2558. <dl compact="compact">
    2559. 

  2559. <dt>&lsquo;<samp>-copyright <var>boolean</var></samp>&rsquo;</dt>
    2560. 

  2560. <dd><p>Copyright Indicator. Specifies whether a copyright exists for this audio.
    2561. 

  2561. </p><dl compact="compact">
    2562. 

  2562. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2563. 

  2563. <dt>&lsquo;<samp>off</samp>&rsquo;</dt>
    2564. 

  2564. <dd><p>No Copyright Exists (default)
    2565. 

  2565. </p></dd>
    2566. 

  2566. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2567. 

  2567. <dt>&lsquo;<samp>on</samp>&rsquo;</dt>
    2568. 

  2568. <dd><p>Copyright Exists
    2569. 

  2569. </p></dd>
    2570. 

  2570. </dl>
    2571. 

  2571. 

  2572. </dd>
    2573. 

  2573. <dt>&lsquo;<samp>-dialnorm <var>value</var></samp>&rsquo;</dt>
    2574. 

  2574. <dd><p>Dialogue Normalization. Indicates how far the average dialogue level of the
    2575. 

  2575. program is below digital 100% full scale (0 dBFS). This parameter determines a
    2576. 

  2576. level shift during audio reproduction that sets the average volume of the
    2577. 

  2577. dialogue to a preset level. The goal is to match volume level between program
    2578. 

  2578. sources. A value of -31dB will result in no volume level change, relative to
    2579. 

  2579. the source volume, during audio reproduction. Valid values are whole numbers in
    2580. 

  2580. the range -31 to -1, with -31 being the default.
    2581. 

  2581. </p>
    2582. 

  2582. </dd>
    2583. 

  2583. <dt>&lsquo;<samp>-dsur_mode <var>mode</var></samp>&rsquo;</dt>
    2584. 

  2584. <dd><p>Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
    2585. 

  2585. (Pro Logic). This field will only be written to the bitstream if the audio
    2586. 

  2586. stream is stereo. Using this option does <b>NOT</b> mean the encoder will actually
    2587. 

  2587. apply Dolby Surround processing.
    2588. 

  2588. </p><dl compact="compact">
    2589. 

  2589. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2590. 

  2590. <dt>&lsquo;<samp>notindicated</samp>&rsquo;</dt>
    2591. 

  2591. <dd><p>Not Indicated (default)
    2592. 

  2592. </p></dd>
    2593. 

  2593. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2594. 

  2594. <dt>&lsquo;<samp>off</samp>&rsquo;</dt>
    2595. 

  2595. <dd><p>Not Dolby Surround Encoded
    2596. 

  2596. </p></dd>
    2597. 

  2597. <dt>&lsquo;<samp>2</samp>&rsquo;</dt>
    2598. 

  2598. <dt>&lsquo;<samp>on</samp>&rsquo;</dt>
    2599. 

  2599. <dd><p>Dolby Surround Encoded
    2600. 

  2600. </p></dd>
    2601. 

  2601. </dl>
    2602. 

  2602. 

  2603. </dd>
    2604. 

  2604. <dt>&lsquo;<samp>-original <var>boolean</var></samp>&rsquo;</dt>
    2605. 

  2605. <dd><p>Original Bit Stream Indicator. Specifies whether this audio is from the
    2606. 

  2606. original source and not a copy.
    2607. 

  2607. </p><dl compact="compact">
    2608. 

  2608. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2609. 

  2609. <dt>&lsquo;<samp>off</samp>&rsquo;</dt>
    2610. 

  2610. <dd><p>Not Original Source
    2611. 

  2611. </p></dd>
    2612. 

  2612. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2613. 

  2613. <dt>&lsquo;<samp>on</samp>&rsquo;</dt>
    2614. 

  2614. <dd><p>Original Source (default)
    2615. 

  2615. </p></dd>
    2616. 

  2616. </dl>
    2617. 

  2617. 

  2618. </dd>
    2619. 

  2619. </dl>
    2620. 

  2620. 

  2621. <a name="Extended-Bitstream-Information"></a>
    2622. 

  2622. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Extended-Bitstream-Information">8.2.2 Extended Bitstream Information</a></h3>
    2623. 

  2623. <p>The extended bitstream options are part of the Alternate Bit Stream Syntax as
    2624. 

  2624. specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
    2625. 

  2625. If any one parameter in a group is specified, all values in that group will be
    2626. 

  2626. written to the bitstream.  Default values are used for those that are written
    2627. 

  2627. but have not been specified.  If the mixing levels are written, the decoder
    2628. 

  2628. will use these values instead of the ones specified in the <code>center_mixlev</code>
    2629. 

  2629. and <code>surround_mixlev</code> options if it supports the Alternate Bit Stream
    2630. 

  2630. Syntax.
    2631. 

  2631. </p>
    2632. 

  2632. <a name="Extended-Bitstream-Information-_002d-Part-1"></a>
    2633. 

  2633. <h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Extended-Bitstream-Information-_002d-Part-1">8.2.2.1 Extended Bitstream Information - Part 1</a></h4>
    2634. 

  2634. 

  2635. <dl compact="compact">
    2636. 

  2636. <dt>&lsquo;<samp>-dmix_mode <var>mode</var></samp>&rsquo;</dt>
    2637. 

  2637. <dd><p>Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
    2638. 

  2638. (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
    2639. 

  2639. </p><dl compact="compact">
    2640. 

  2640. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2641. 

  2641. <dt>&lsquo;<samp>notindicated</samp>&rsquo;</dt>
    2642. 

  2642. <dd><p>Not Indicated (default)
    2643. 

  2643. </p></dd>
    2644. 

  2644. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2645. 

  2645. <dt>&lsquo;<samp>ltrt</samp>&rsquo;</dt>
    2646. 

  2646. <dd><p>Lt/Rt Downmix Preferred
    2647. 

  2647. </p></dd>
    2648. 

  2648. <dt>&lsquo;<samp>2</samp>&rsquo;</dt>
    2649. 

  2649. <dt>&lsquo;<samp>loro</samp>&rsquo;</dt>
    2650. 

  2650. <dd><p>Lo/Ro Downmix Preferred
    2651. 

  2651. </p></dd>
    2652. 

  2652. </dl>
    2653. 

  2653. 

  2654. </dd>
    2655. 

  2655. <dt>&lsquo;<samp>-ltrt_cmixlev <var>level</var></samp>&rsquo;</dt>
    2656. 

  2656. <dd><p>Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
    2657. 

  2657. center channel when downmixing to stereo in Lt/Rt mode.
    2658. 

  2658. </p><dl compact="compact">
    2659. 

  2659. <dt>&lsquo;<samp>1.414</samp>&rsquo;</dt>
    2660. 

  2660. <dd><p>Apply +3dB gain
    2661. 

  2661. </p></dd>
    2662. 

  2662. <dt>&lsquo;<samp>1.189</samp>&rsquo;</dt>
    2663. 

  2663. <dd><p>Apply +1.5dB gain
    2664. 

  2664. </p></dd>
    2665. 

  2665. <dt>&lsquo;<samp>1.000</samp>&rsquo;</dt>
    2666. 

  2666. <dd><p>Apply 0dB gain
    2667. 

  2667. </p></dd>
    2668. 

  2668. <dt>&lsquo;<samp>0.841</samp>&rsquo;</dt>
    2669. 

  2669. <dd><p>Apply -1.5dB gain
    2670. 

  2670. </p></dd>
    2671. 

  2671. <dt>&lsquo;<samp>0.707</samp>&rsquo;</dt>
    2672. 

  2672. <dd><p>Apply -3.0dB gain
    2673. 

  2673. </p></dd>
    2674. 

  2674. <dt>&lsquo;<samp>0.595</samp>&rsquo;</dt>
    2675. 

  2675. <dd><p>Apply -4.5dB gain (default)
    2676. 

  2676. </p></dd>
    2677. 

  2677. <dt>&lsquo;<samp>0.500</samp>&rsquo;</dt>
    2678. 

  2678. <dd><p>Apply -6.0dB gain
    2679. 

  2679. </p></dd>
    2680. 

  2680. <dt>&lsquo;<samp>0.000</samp>&rsquo;</dt>
    2681. 

  2681. <dd><p>Silence Center Channel
    2682. 

  2682. </p></dd>
    2683. 

  2683. </dl>
    2684. 

  2684. 

  2685. </dd>
    2686. 

  2686. <dt>&lsquo;<samp>-ltrt_surmixlev <var>level</var></samp>&rsquo;</dt>
    2687. 

  2687. <dd><p>Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
    2688. 

  2688. surround channel(s) when downmixing to stereo in Lt/Rt mode.
    2689. 

  2689. </p><dl compact="compact">
    2690. 

  2690. <dt>&lsquo;<samp>0.841</samp>&rsquo;</dt>
    2691. 

  2691. <dd><p>Apply -1.5dB gain
    2692. 

  2692. </p></dd>
    2693. 

  2693. <dt>&lsquo;<samp>0.707</samp>&rsquo;</dt>
    2694. 

  2694. <dd><p>Apply -3.0dB gain
    2695. 

  2695. </p></dd>
    2696. 

  2696. <dt>&lsquo;<samp>0.595</samp>&rsquo;</dt>
    2697. 

  2697. <dd><p>Apply -4.5dB gain
    2698. 

  2698. </p></dd>
    2699. 

  2699. <dt>&lsquo;<samp>0.500</samp>&rsquo;</dt>
    2700. 

  2700. <dd><p>Apply -6.0dB gain (default)
    2701. 

  2701. </p></dd>
    2702. 

  2702. <dt>&lsquo;<samp>0.000</samp>&rsquo;</dt>
    2703. 

  2703. <dd><p>Silence Surround Channel(s)
    2704. 

  2704. </p></dd>
    2705. 

  2705. </dl>
    2706. 

  2706. 

  2707. </dd>
    2708. 

  2708. <dt>&lsquo;<samp>-loro_cmixlev <var>level</var></samp>&rsquo;</dt>
    2709. 

  2709. <dd><p>Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
    2710. 

  2710. center channel when downmixing to stereo in Lo/Ro mode.
    2711. 

  2711. </p><dl compact="compact">
    2712. 

  2712. <dt>&lsquo;<samp>1.414</samp>&rsquo;</dt>
    2713. 

  2713. <dd><p>Apply +3dB gain
    2714. 

  2714. </p></dd>
    2715. 

  2715. <dt>&lsquo;<samp>1.189</samp>&rsquo;</dt>
    2716. 

  2716. <dd><p>Apply +1.5dB gain
    2717. 

  2717. </p></dd>
    2718. 

  2718. <dt>&lsquo;<samp>1.000</samp>&rsquo;</dt>
    2719. 

  2719. <dd><p>Apply 0dB gain
    2720. 

  2720. </p></dd>
    2721. 

  2721. <dt>&lsquo;<samp>0.841</samp>&rsquo;</dt>
    2722. 

  2722. <dd><p>Apply -1.5dB gain
    2723. 

  2723. </p></dd>
    2724. 

  2724. <dt>&lsquo;<samp>0.707</samp>&rsquo;</dt>
    2725. 

  2725. <dd><p>Apply -3.0dB gain
    2726. 

  2726. </p></dd>
    2727. 

  2727. <dt>&lsquo;<samp>0.595</samp>&rsquo;</dt>
    2728. 

  2728. <dd><p>Apply -4.5dB gain (default)
    2729. 

  2729. </p></dd>
    2730. 

  2730. <dt>&lsquo;<samp>0.500</samp>&rsquo;</dt>
    2731. 

  2731. <dd><p>Apply -6.0dB gain
    2732. 

  2732. </p></dd>
    2733. 

  2733. <dt>&lsquo;<samp>0.000</samp>&rsquo;</dt>
    2734. 

  2734. <dd><p>Silence Center Channel
    2735. 

  2735. </p></dd>
    2736. 

  2736. </dl>
    2737. 

  2737. 

  2738. </dd>
    2739. 

  2739. <dt>&lsquo;<samp>-loro_surmixlev <var>level</var></samp>&rsquo;</dt>
    2740. 

  2740. <dd><p>Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
    2741. 

  2741. surround channel(s) when downmixing to stereo in Lo/Ro mode.
    2742. 

  2742. </p><dl compact="compact">
    2743. 

  2743. <dt>&lsquo;<samp>0.841</samp>&rsquo;</dt>
    2744. 

  2744. <dd><p>Apply -1.5dB gain
    2745. 

  2745. </p></dd>
    2746. 

  2746. <dt>&lsquo;<samp>0.707</samp>&rsquo;</dt>
    2747. 

  2747. <dd><p>Apply -3.0dB gain
    2748. 

  2748. </p></dd>
    2749. 

  2749. <dt>&lsquo;<samp>0.595</samp>&rsquo;</dt>
    2750. 

  2750. <dd><p>Apply -4.5dB gain
    2751. 

  2751. </p></dd>
    2752. 

  2752. <dt>&lsquo;<samp>0.500</samp>&rsquo;</dt>
    2753. 

  2753. <dd><p>Apply -6.0dB gain (default)
    2754. 

  2754. </p></dd>
    2755. 

  2755. <dt>&lsquo;<samp>0.000</samp>&rsquo;</dt>
    2756. 

  2756. <dd><p>Silence Surround Channel(s)
    2757. 

  2757. </p></dd>
    2758. 

  2758. </dl>
    2759. 

  2759. 

  2760. </dd>
    2761. 

  2761. </dl>
    2762. 

  2762. 

  2763. <a name="Extended-Bitstream-Information-_002d-Part-2"></a>
    2764. 

  2764. <h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Extended-Bitstream-Information-_002d-Part-2">8.2.2.2 Extended Bitstream Information - Part 2</a></h4>
    2765. 

  2765. 

  2766. <dl compact="compact">
    2767. 

  2767. <dt>&lsquo;<samp>-dsurex_mode <var>mode</var></samp>&rsquo;</dt>
    2768. 

  2768. <dd><p>Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
    2769. 

  2769. (7.1 matrixed to 5.1). Using this option does <b>NOT</b> mean the encoder will actually
    2770. 

  2770. apply Dolby Surround EX processing.
    2771. 

  2771. </p><dl compact="compact">
    2772. 

  2772. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2773. 

  2773. <dt>&lsquo;<samp>notindicated</samp>&rsquo;</dt>
    2774. 

  2774. <dd><p>Not Indicated (default)
    2775. 

  2775. </p></dd>
    2776. 

  2776. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2777. 

  2777. <dt>&lsquo;<samp>on</samp>&rsquo;</dt>
    2778. 

  2778. <dd><p>Dolby Surround EX Off
    2779. 

  2779. </p></dd>
    2780. 

  2780. <dt>&lsquo;<samp>2</samp>&rsquo;</dt>
    2781. 

  2781. <dt>&lsquo;<samp>off</samp>&rsquo;</dt>
    2782. 

  2782. <dd><p>Dolby Surround EX On
    2783. 

  2783. </p></dd>
    2784. 

  2784. </dl>
    2785. 

  2785. 

  2786. </dd>
    2787. 

  2787. <dt>&lsquo;<samp>-dheadphone_mode <var>mode</var></samp>&rsquo;</dt>
    2788. 

  2788. <dd><p>Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
    2789. 

  2789. encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
    2790. 

  2790. option does <b>NOT</b> mean the encoder will actually apply Dolby Headphone
    2791. 

  2791. processing.
    2792. 

  2792. </p><dl compact="compact">
    2793. 

  2793. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2794. 

  2794. <dt>&lsquo;<samp>notindicated</samp>&rsquo;</dt>
    2795. 

  2795. <dd><p>Not Indicated (default)
    2796. 

  2796. </p></dd>
    2797. 

  2797. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2798. 

  2798. <dt>&lsquo;<samp>on</samp>&rsquo;</dt>
    2799. 

  2799. <dd><p>Dolby Headphone Off
    2800. 

  2800. </p></dd>
    2801. 

  2801. <dt>&lsquo;<samp>2</samp>&rsquo;</dt>
    2802. 

  2802. <dt>&lsquo;<samp>off</samp>&rsquo;</dt>
    2803. 

  2803. <dd><p>Dolby Headphone On
    2804. 

  2804. </p></dd>
    2805. 

  2805. </dl>
    2806. 

  2806. 

  2807. </dd>
    2808. 

  2808. <dt>&lsquo;<samp>-ad_conv_type <var>type</var></samp>&rsquo;</dt>
    2809. 

  2809. <dd><p>A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
    2810. 

  2810. conversion.
    2811. 

  2811. </p><dl compact="compact">
    2812. 

  2812. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2813. 

  2813. <dt>&lsquo;<samp>standard</samp>&rsquo;</dt>
    2814. 

  2814. <dd><p>Standard A/D Converter (default)
    2815. 

  2815. </p></dd>
    2816. 

  2816. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2817. 

  2817. <dt>&lsquo;<samp>hdcd</samp>&rsquo;</dt>
    2818. 

  2818. <dd><p>HDCD A/D Converter
    2819. 

  2819. </p></dd>
    2820. 

  2820. </dl>
    2821. 

  2821. 

  2822. </dd>
    2823. 

  2823. </dl>
    2824. 

  2824. 

  2825. <a name="Other-AC_002d3-Encoding-Options"></a>
    2826. 

  2826. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Other-AC_002d3-Encoding-Options">8.2.3 Other AC-3 Encoding Options</a></h3>
    2827. 

  2827. 

  2828. <dl compact="compact">
    2829. 

  2829. <dt>&lsquo;<samp>-stereo_rematrixing <var>boolean</var></samp>&rsquo;</dt>
    2830. 

  2830. <dd><p>Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
    2831. 

  2831. is an optional AC-3 feature that increases quality by selectively encoding
    2832. 

  2832. the left/right channels as mid/side. This option is enabled by default, and it
    2833. 

  2833. is highly recommended that it be left as enabled except for testing purposes.
    2834. 

  2834. </p>
    2835. 

  2835. </dd>
    2836. 

  2836. <dt>&lsquo;<samp>cutoff <var>frequency</var></samp>&rsquo;</dt>
    2837. 

  2837. <dd><p>Set lowpass cutoff frequency. If unspecified, the encoder selects a default
    2838. 

  2838. determined by various other encoding parameters.
    2839. 

  2839. </p>
    2840. 

  2840. </dd>
    2841. 

  2841. </dl>
    2842. 

  2842. 

  2843. <a name="Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options"></a>
    2844. 

  2844. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Floating_002dPoint_002dOnly-AC_002d3-Encoding-Options">8.2.4 Floating-Point-Only AC-3 Encoding Options</a></h3>
    2845. 

  2845. 

  2846. <p>These options are only valid for the floating-point encoder and do not exist
    2847. 

  2847. for the fixed-point encoder due to the corresponding features not being
    2848. 

  2848. implemented in fixed-point.
    2849. 

  2849. </p>
    2850. 

  2850. <dl compact="compact">
    2851. 

  2851. <dt>&lsquo;<samp>-channel_coupling <var>boolean</var></samp>&rsquo;</dt>
    2852. 

  2852. <dd><p>Enables/Disables use of channel coupling, which is an optional AC-3 feature
    2853. 

  2853. that increases quality by combining high frequency information from multiple
    2854. 

  2854. channels into a single channel. The per-channel high frequency information is
    2855. 

  2855. sent with less accuracy in both the frequency and time domains. This allows
    2856. 

  2856. more bits to be used for lower frequencies while preserving enough information
    2857. 

  2857. to reconstruct the high frequencies. This option is enabled by default for the
    2858. 

  2858. floating-point encoder and should generally be left as enabled except for
    2859. 

  2859. testing purposes or to increase encoding speed.
    2860. 

  2860. </p><dl compact="compact">
    2861. 

  2861. <dt>&lsquo;<samp>-1</samp>&rsquo;</dt>
    2862. 

  2862. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    2863. 

  2863. <dd><p>Selected by Encoder (default)
    2864. 

  2864. </p></dd>
    2865. 

  2865. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    2866. 

  2866. <dt>&lsquo;<samp>off</samp>&rsquo;</dt>
    2867. 

  2867. <dd><p>Disable Channel Coupling
    2868. 

  2868. </p></dd>
    2869. 

  2869. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    2870. 

  2870. <dt>&lsquo;<samp>on</samp>&rsquo;</dt>
    2871. 

  2871. <dd><p>Enable Channel Coupling
    2872. 

  2872. </p></dd>
    2873. 

  2873. </dl>
    2874. 

  2874. 

  2875. </dd>
    2876. 

  2876. <dt>&lsquo;<samp>-cpl_start_band <var>number</var></samp>&rsquo;</dt>
    2877. 

  2877. <dd><p>Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
    2878. 

  2878. value higher than the bandwidth is used, it will be reduced to 1 less than the
    2879. 

  2879. coupling end band. If <var>auto</var> is used, the start band will be determined by
    2880. 

  2880. the encoder based on the bit rate, sample rate, and channel layout. This option
    2881. 

  2881. has no effect if channel coupling is disabled.
    2882. 

  2882. </p><dl compact="compact">
    2883. 

  2883. <dt>&lsquo;<samp>-1</samp>&rsquo;</dt>
    2884. 

  2884. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    2885. 

  2885. <dd><p>Selected by Encoder (default)
    2886. 

  2886. </p></dd>
    2887. 

  2887. </dl>
    2888. 

  2888. 

  2889. </dd>
    2890. 

  2890. </dl>
    2891. 

  2891. 

  2892. <p><a name="flac"></a>
    2893. 

  2893. </p><a name="flac-2"></a>
    2894. 

  2894. <h2 class="section"><a href="ffmpeg-codecs.html#toc-flac-2">8.3 flac</a></h2>
    2895. 

  2895. 

  2896. <p>FLAC (Free Lossless Audio Codec) Encoder
    2897. 

  2897. </p>
    2898. 

  2898. <a name="Options-5"></a>
    2899. 

  2899. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-5">8.3.1 Options</a></h3>
    2900. 

  2900. 

  2901. <p>The following options are supported by FFmpeg&rsquo;s flac encoder.
    2902. 

  2902. </p>
    2903. 

  2903. <dl compact="compact">
    2904. 

  2904. <dt>&lsquo;<samp>compression_level</samp>&rsquo;</dt>
    2905. 

  2905. <dd><p>Sets the compression level, which chooses defaults for many other options
    2906. 

  2906. if they are not set explicitly. Valid values are from 0 to 12, 5 is the
    2907. 

  2907. default.
    2908. 

  2908. </p>
    2909. 

  2909. </dd>
    2910. 

  2910. <dt>&lsquo;<samp>frame_size</samp>&rsquo;</dt>
    2911. 

  2911. <dd><p>Sets the size of the frames in samples per channel.
    2912. 

  2912. </p>
    2913. 

  2913. </dd>
    2914. 

  2914. <dt>&lsquo;<samp>lpc_coeff_precision</samp>&rsquo;</dt>
    2915. 

  2915. <dd><p>Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the
    2916. 

  2916. default.
    2917. 

  2917. </p>
    2918. 

  2918. </dd>
    2919. 

  2919. <dt>&lsquo;<samp>lpc_type</samp>&rsquo;</dt>
    2920. 

  2920. <dd><p>Sets the first stage LPC algorithm
    2921. 

  2921. </p><dl compact="compact">
    2922. 

  2922. <dt>&lsquo;<samp>none</samp>&rsquo;</dt>
    2923. 

  2923. <dd><p>LPC is not used
    2924. 

  2924. </p>
    2925. 

  2925. </dd>
    2926. 

  2926. <dt>&lsquo;<samp>fixed</samp>&rsquo;</dt>
    2927. 

  2927. <dd><p>fixed LPC coefficients
    2928. 

  2928. </p>
    2929. 

  2929. </dd>
    2930. 

  2930. <dt>&lsquo;<samp>levinson</samp>&rsquo;</dt>
    2931. 

  2931. <dt>&lsquo;<samp>cholesky</samp>&rsquo;</dt>
    2932. 

  2932. </dl>
    2933. 

  2933. 

  2934. </dd>
    2935. 

  2935. <dt>&lsquo;<samp>lpc_passes</samp>&rsquo;</dt>
    2936. 

  2936. <dd><p>Number of passes to use for Cholesky factorization during LPC analysis
    2937. 

  2937. </p>
    2938. 

  2938. </dd>
    2939. 

  2939. <dt>&lsquo;<samp>min_partition_order</samp>&rsquo;</dt>
    2940. 

  2940. <dd><p>The minimum partition order
    2941. 

  2941. </p>
    2942. 

  2942. </dd>
    2943. 

  2943. <dt>&lsquo;<samp>max_partition_order</samp>&rsquo;</dt>
    2944. 

  2944. <dd><p>The maximum partition order
    2945. 

  2945. </p>
    2946. 

  2946. </dd>
    2947. 

  2947. <dt>&lsquo;<samp>prediction_order_method</samp>&rsquo;</dt>
    2948. 

  2948. <dd><dl compact="compact">
    2949. 

  2949. <dt>&lsquo;<samp>estimation</samp>&rsquo;</dt>
    2950. 

  2950. <dt>&lsquo;<samp>2level</samp>&rsquo;</dt>
    2951. 

  2951. <dt>&lsquo;<samp>4level</samp>&rsquo;</dt>
    2952. 

  2952. <dt>&lsquo;<samp>8level</samp>&rsquo;</dt>
    2953. 

  2953. <dt>&lsquo;<samp>search</samp>&rsquo;</dt>
    2954. 

  2954. <dd><p>Bruteforce search
    2955. 

  2955. </p></dd>
    2956. 

  2956. <dt>&lsquo;<samp>log</samp>&rsquo;</dt>
    2957. 

  2957. </dl>
    2958. 

  2958. 

  2959. </dd>
    2960. 

  2960. <dt>&lsquo;<samp>ch_mode</samp>&rsquo;</dt>
    2961. 

  2961. <dd><p>Channel mode
    2962. 

  2962. </p><dl compact="compact">
    2963. 

  2963. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    2964. 

  2964. <dd><p>The mode is chosen automatically for each frame
    2965. 

  2965. </p></dd>
    2966. 

  2966. <dt>&lsquo;<samp>indep</samp>&rsquo;</dt>
    2967. 

  2967. <dd><p>Channels are independently coded
    2968. 

  2968. </p></dd>
    2969. 

  2969. <dt>&lsquo;<samp>left_side</samp>&rsquo;</dt>
    2970. 

  2970. <dt>&lsquo;<samp>right_side</samp>&rsquo;</dt>
    2971. 

  2971. <dt>&lsquo;<samp>mid_side</samp>&rsquo;</dt>
    2972. 

  2972. </dl>
    2973. 

  2973. 

  2974. </dd>
    2975. 

  2975. <dt>&lsquo;<samp>exact_rice_parameters</samp>&rsquo;</dt>
    2976. 

  2976. <dd><p>Chooses if rice parameters are calculated exactly or approximately.
    2977. 

  2977. if set to 1 then they are chosen exactly, which slows the code down slightly and
    2978. 

  2978. improves compression slightly.
    2979. 

  2979. </p>
    2980. 

  2980. </dd>
    2981. 

  2981. <dt>&lsquo;<samp>multi_dim_quant</samp>&rsquo;</dt>
    2982. 

  2982. <dd><p>Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is
    2983. 

  2983. applied after the first stage to finetune the coefficients. This is quite slow
    2984. 

  2984. and slightly improves compression.
    2985. 

  2985. </p>
    2986. 

  2986. </dd>
    2987. 

  2987. </dl>
    2988. 

  2988. 

  2989. <p><a name="opusenc"></a>
    2990. 

  2990. </p><a name="opus"></a>
    2991. 

  2991. <h2 class="section"><a href="ffmpeg-codecs.html#toc-opus">8.4 opus</a></h2>
    2992. 

  2992. 

  2993. <p>Opus encoder.
    2994. 

  2994. </p>
    2995. 

  2995. <p>This is a native FFmpeg encoder for the Opus format. Currently its in development and
    2996. 

  2996. only implements the CELT part of the codec. Its quality is usually worse and at best
    2997. 

  2997. is equal to the libopus encoder.
    2998. 

  2998. </p>
    2999. 

  2999. <a name="Options-32"></a>
    3000. 

  3000. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-32">8.4.1 Options</a></h3>
    3001. 

  3001. 

  3002. <dl compact="compact">
    3003. 

  3003. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    3004. 

  3004. <dd><p>Set bit rate in bits/s. If unspecified it uses the number of channels and the layout
    3005. 

  3005. to make a good guess.
    3006. 

  3006. </p>
    3007. 

  3007. </dd>
    3008. 

  3008. <dt>&lsquo;<samp>opus_delay</samp>&rsquo;</dt>
    3009. 

  3009. <dd><p>Sets the maximum delay in milliseconds. Lower delays than 20ms will very quickly
    3010. 

  3010. decrease quality.
    3011. 

  3011. </p></dd>
    3012. 

  3012. </dl>
    3013. 

  3013. 

  3014. <p><a name="libfdk_002daac_002denc"></a>
    3015. 

  3015. </p><a name="libfdk_005faac"></a>
    3016. 

  3016. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libfdk_005faac">8.5 libfdk_aac</a></h2>
    3017. 

  3017. 

  3018. <p>libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
    3019. 

  3019. </p>
    3020. 

  3020. <p>The libfdk-aac library is based on the Fraunhofer FDK AAC code from
    3021. 

  3021. the Android project.
    3022. 

  3022. </p>
    3023. 

  3023. <p>Requires the presence of the libfdk-aac headers and library during
    3024. 

  3024. configuration. You need to explicitly configure the build with
    3025. 

  3025. <code>--enable-libfdk-aac</code>. The library is also incompatible with GPL,
    3026. 

  3026. so if you allow the use of GPL, you should configure with
    3027. 

  3027. <code>--enable-gpl --enable-nonfree --enable-libfdk-aac</code>.
    3028. 

  3028. </p>
    3029. 

  3029. <p>This encoder has support for the AAC-HE profiles.
    3030. 

  3030. </p>
    3031. 

  3031. <p>VBR encoding, enabled through the &lsquo;<samp>vbr</samp>&rsquo; or &lsquo;<samp>flags
    3032. 

  3032. +qscale</samp>&rsquo; options, is experimental and only works with some
    3033. 

  3033. combinations of parameters.
    3034. 

  3034. </p>
    3035. 

  3035. <p>Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
    3036. 

  3036. higher.
    3037. 

  3037. </p>
    3038. 

  3038. <p>For more information see the fdk-aac project at
    3039. 

  3039. <a href="http://sourceforge.net/p/opencore-amr/fdk-aac/">http://sourceforge.net/p/opencore-amr/fdk-aac/</a>.
    3040. 

  3040. </p>
    3041. 

  3041. <a name="Options-19"></a>
    3042. 

  3042. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-19">8.5.1 Options</a></h3>
    3043. 

  3043. 

  3044. <p>The following options are mapped on the shared FFmpeg codec options.
    3045. 

  3045. </p>
    3046. 

  3046. <dl compact="compact">
    3047. 

  3047. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    3048. 

  3048. <dd><p>Set bit rate in bits/s. If the bitrate is not explicitly specified, it
    3049. 

  3049. is automatically set to a suitable value depending on the selected
    3050. 

  3050. profile.
    3051. 

  3051. </p>
    3052. 

  3052. <p>In case VBR mode is enabled the option is ignored.
    3053. 

  3053. </p>
    3054. 

  3054. </dd>
    3055. 

  3055. <dt>&lsquo;<samp>ar</samp>&rsquo;</dt>
    3056. 

  3056. <dd><p>Set audio sampling rate (in Hz).
    3057. 

  3057. </p>
    3058. 

  3058. </dd>
    3059. 

  3059. <dt>&lsquo;<samp>channels</samp>&rsquo;</dt>
    3060. 

  3060. <dd><p>Set the number of audio channels.
    3061. 

  3061. </p>
    3062. 

  3062. </dd>
    3063. 

  3063. <dt>&lsquo;<samp>flags +qscale</samp>&rsquo;</dt>
    3064. 

  3064. <dd><p>Enable fixed quality, VBR (Variable Bit Rate) mode.
    3065. 

  3065. Note that VBR is implicitly enabled when the &lsquo;<samp>vbr</samp>&rsquo; value is
    3066. 

  3066. positive.
    3067. 

  3067. </p>
    3068. 

  3068. </dd>
    3069. 

  3069. <dt>&lsquo;<samp>cutoff</samp>&rsquo;</dt>
    3070. 

  3070. <dd><p>Set cutoff frequency. If not specified (or explicitly set to 0) it
    3071. 

  3071. will use a value automatically computed by the library. Default value
    3072. 

  3072. is 0.
    3073. 

  3073. </p>
    3074. 

  3074. </dd>
    3075. 

  3075. <dt>&lsquo;<samp>profile</samp>&rsquo;</dt>
    3076. 

  3076. <dd><p>Set audio profile.
    3077. 

  3077. </p>
    3078. 

  3078. <p>The following profiles are recognized:
    3079. 

  3079. </p><dl compact="compact">
    3080. 

  3080. <dt>&lsquo;<samp>aac_low</samp>&rsquo;</dt>
    3081. 

  3081. <dd><p>Low Complexity AAC (LC)
    3082. 

  3082. </p>
    3083. 

  3083. </dd>
    3084. 

  3084. <dt>&lsquo;<samp>aac_he</samp>&rsquo;</dt>
    3085. 

  3085. <dd><p>High Efficiency AAC (HE-AAC)
    3086. 

  3086. </p>
    3087. 

  3087. </dd>
    3088. 

  3088. <dt>&lsquo;<samp>aac_he_v2</samp>&rsquo;</dt>
    3089. 

  3089. <dd><p>High Efficiency AAC version 2 (HE-AACv2)
    3090. 

  3090. </p>
    3091. 

  3091. </dd>
    3092. 

  3092. <dt>&lsquo;<samp>aac_ld</samp>&rsquo;</dt>
    3093. 

  3093. <dd><p>Low Delay AAC (LD)
    3094. 

  3094. </p>
    3095. 

  3095. </dd>
    3096. 

  3096. <dt>&lsquo;<samp>aac_eld</samp>&rsquo;</dt>
    3097. 

  3097. <dd><p>Enhanced Low Delay AAC (ELD)
    3098. 

  3098. </p></dd>
    3099. 

  3099. </dl>
    3100. 

  3100. 

  3101. <p>If not specified it is set to &lsquo;<samp>aac_low</samp>&rsquo;.
    3102. 

  3102. </p></dd>
    3103. 

  3103. </dl>
    3104. 

  3104. 

  3105. <p>The following are private options of the libfdk_aac encoder.
    3106. 

  3106. </p>
    3107. 

  3107. <dl compact="compact">
    3108. 

  3108. <dt>&lsquo;<samp>afterburner</samp>&rsquo;</dt>
    3109. 

  3109. <dd><p>Enable afterburner feature if set to 1, disabled if set to 0. This
    3110. 

  3110. improves the quality but also the required processing power.
    3111. 

  3111. </p>
    3112. 

  3112. <p>Default value is 1.
    3113. 

  3113. </p>
    3114. 

  3114. </dd>
    3115. 

  3115. <dt>&lsquo;<samp>eld_sbr</samp>&rsquo;</dt>
    3116. 

  3116. <dd><p>Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
    3117. 

  3117. if set to 0.
    3118. 

  3118. </p>
    3119. 

  3119. <p>Default value is 0.
    3120. 

  3120. </p>
    3121. 

  3121. </dd>
    3122. 

  3122. <dt>&lsquo;<samp>eld_v2</samp>&rsquo;</dt>
    3123. 

  3123. <dd><p>Enable ELDv2 (LD-MPS extension for ELD stereo signals) for ELDv2 if set to 1,
    3124. 

  3124. disabled if set to 0.
    3125. 

  3125. </p>
    3126. 

  3126. <p>Note that option is available when fdk-aac version (AACENCODER_LIB_VL0.AACENCODER_LIB_VL1.AACENCODER_LIB_VL2) &gt; (4.0.0).
    3127. 

  3127. </p>
    3128. 

  3128. <p>Default value is 0.
    3129. 

  3129. </p>
    3130. 

  3130. </dd>
    3131. 

  3131. <dt>&lsquo;<samp>signaling</samp>&rsquo;</dt>
    3132. 

  3132. <dd><p>Set SBR/PS signaling style.
    3133. 

  3133. </p>
    3134. 

  3134. <p>It can assume one of the following values:
    3135. 

  3135. </p><dl compact="compact">
    3136. 

  3136. <dt>&lsquo;<samp>default</samp>&rsquo;</dt>
    3137. 

  3137. <dd><p>choose signaling implicitly (explicit hierarchical by default,
    3138. 

  3138. implicit if global header is disabled)
    3139. 

  3139. </p>
    3140. 

  3140. </dd>
    3141. 

  3141. <dt>&lsquo;<samp>implicit</samp>&rsquo;</dt>
    3142. 

  3142. <dd><p>implicit backwards compatible signaling
    3143. 

  3143. </p>
    3144. 

  3144. </dd>
    3145. 

  3145. <dt>&lsquo;<samp>explicit_sbr</samp>&rsquo;</dt>
    3146. 

  3146. <dd><p>explicit SBR, implicit PS signaling
    3147. 

  3147. </p>
    3148. 

  3148. </dd>
    3149. 

  3149. <dt>&lsquo;<samp>explicit_hierarchical</samp>&rsquo;</dt>
    3150. 

  3150. <dd><p>explicit hierarchical signaling
    3151. 

  3151. </p></dd>
    3152. 

  3152. </dl>
    3153. 

  3153. 

  3154. <p>Default value is &lsquo;<samp>default</samp>&rsquo;.
    3155. 

  3155. </p>
    3156. 

  3156. </dd>
    3157. 

  3157. <dt>&lsquo;<samp>latm</samp>&rsquo;</dt>
    3158. 

  3158. <dd><p>Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
    3159. 

  3159. </p>
    3160. 

  3160. <p>Default value is 0.
    3161. 

  3161. </p>
    3162. 

  3162. </dd>
    3163. 

  3163. <dt>&lsquo;<samp>header_period</samp>&rsquo;</dt>
    3164. 

  3164. <dd><p>Set StreamMuxConfig and PCE repetition period (in frames) for sending
    3165. 

  3165. in-band configuration buffers within LATM/LOAS transport layer.
    3166. 

  3166. </p>
    3167. 

  3167. <p>Must be a 16-bits non-negative integer.
    3168. 

  3168. </p>
    3169. 

  3169. <p>Default value is 0.
    3170. 

  3170. </p>
    3171. 

  3171. </dd>
    3172. 

  3172. <dt>&lsquo;<samp>vbr</samp>&rsquo;</dt>
    3173. 

  3173. <dd><p>Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
    3174. 

  3174. good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
    3175. 

  3175. (Constant Bit Rate) is enabled.
    3176. 

  3176. </p>
    3177. 

  3177. <p>Currently only the &lsquo;<samp>aac_low</samp>&rsquo; profile supports VBR encoding.
    3178. 

  3178. </p>
    3179. 

  3179. <p>VBR modes 1-5 correspond to roughly the following average bit rates:
    3180. 

  3180. </p>
    3181. 

  3181. <dl compact="compact">
    3182. 

  3182. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    3183. 

  3183. <dd><p>32 kbps/channel
    3184. 

  3184. </p></dd>
    3185. 

  3185. <dt>&lsquo;<samp>2</samp>&rsquo;</dt>
    3186. 

  3186. <dd><p>40 kbps/channel
    3187. 

  3187. </p></dd>
    3188. 

  3188. <dt>&lsquo;<samp>3</samp>&rsquo;</dt>
    3189. 

  3189. <dd><p>48-56 kbps/channel
    3190. 

  3190. </p></dd>
    3191. 

  3191. <dt>&lsquo;<samp>4</samp>&rsquo;</dt>
    3192. 

  3192. <dd><p>64 kbps/channel
    3193. 

  3193. </p></dd>
    3194. 

  3194. <dt>&lsquo;<samp>5</samp>&rsquo;</dt>
    3195. 

  3195. <dd><p>about 80-96 kbps/channel
    3196. 

  3196. </p></dd>
    3197. 

  3197. </dl>
    3198. 

  3198. 

  3199. <p>Default value is 0.
    3200. 

  3200. </p></dd>
    3201. 

  3201. </dl>
    3202. 

  3202. 

  3203. <a name="Examples"></a>
    3204. 

  3204. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Examples">8.5.2 Examples</a></h3>
    3205. 

  3205. 

  3206. <ul>
    3207. 

  3207. <li>
    3208. 

  3208. Use <code>ffmpeg</code> to convert an audio file to VBR AAC in an M4A (MP4)
    3209. 

  3209. container:
    3210. 

  3210. <div class="example">
    3211. 

  3211. <pre class="example">ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
    3212. 

  3212. </pre></div>
    3213. 

  3213. 

  3214. </li><li>
    3215. 

  3215. Use <code>ffmpeg</code> to convert an audio file to CBR 64k kbps AAC, using the
    3216. 

  3216. High-Efficiency AAC profile:
    3217. 

  3217. <div class="example">
    3218. 

  3218. <pre class="example">ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
    3219. 

  3219. </pre></div>
    3220. 

  3220. </li></ul>
    3221. 

  3221. 

  3222. <p><a name="libmp3lame"></a>
    3223. 

  3223. </p><a name="libmp3lame-1"></a>
    3224. 

  3224. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libmp3lame-1">8.6 libmp3lame</a></h2>
    3225. 

  3225. 

  3226. <p>LAME (Lame Ain&rsquo;t an MP3 Encoder) MP3 encoder wrapper.
    3227. 

  3227. </p>
    3228. 

  3228. <p>Requires the presence of the libmp3lame headers and library during
    3229. 

  3229. configuration. You need to explicitly configure the build with
    3230. 

  3230. <code>--enable-libmp3lame</code>.
    3231. 

  3231. </p>
    3232. 

  3232. <p>See <a href="#libshine">libshine</a> for a fixed-point MP3 encoder, although with a
    3233. 

  3233. lower quality.
    3234. 

  3234. </p>
    3235. 

  3235. <a name="Options-11"></a>
    3236. 

  3236. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-11">8.6.1 Options</a></h3>
    3237. 

  3237. 

  3238. <p>The following options are supported by the libmp3lame wrapper. The
    3239. 

  3239. <code>lame</code>-equivalent of the options are listed in parentheses.
    3240. 

  3240. </p>
    3241. 

  3241. <dl compact="compact">
    3242. 

  3242. <dt>&lsquo;<samp>b (<em>-b</em>)</samp>&rsquo;</dt>
    3243. 

  3243. <dd><p>Set bitrate expressed in bits/s for CBR or ABR. LAME <code>bitrate</code> is
    3244. 

  3244. expressed in kilobits/s.
    3245. 

  3245. </p>
    3246. 

  3246. </dd>
    3247. 

  3247. <dt>&lsquo;<samp>q (<em>-V</em>)</samp>&rsquo;</dt>
    3248. 

  3248. <dd><p>Set constant quality setting for VBR. This option is valid only
    3249. 

  3249. using the <code>ffmpeg</code> command-line tool. For library interface
    3250. 

  3250. users, use &lsquo;<samp>global_quality</samp>&rsquo;.
    3251. 

  3251. </p>
    3252. 

  3252. </dd>
    3253. 

  3253. <dt>&lsquo;<samp>compression_level (<em>-q</em>)</samp>&rsquo;</dt>
    3254. 

  3254. <dd><p>Set algorithm quality. Valid arguments are integers in the 0-9 range,
    3255. 

  3255. with 0 meaning highest quality but slowest, and 9 meaning fastest
    3256. 

  3256. while producing the worst quality.
    3257. 

  3257. </p>
    3258. 

  3258. </dd>
    3259. 

  3259. <dt>&lsquo;<samp>cutoff (<em>--lowpass</em>)</samp>&rsquo;</dt>
    3260. 

  3260. <dd><p>Set lowpass cutoff frequency. If unspecified, the encoder dynamically
    3261. 

  3261. adjusts the cutoff.
    3262. 

  3262. </p>
    3263. 

  3263. </dd>
    3264. 

  3264. <dt>&lsquo;<samp>reservoir</samp>&rsquo;</dt>
    3265. 

  3265. <dd><p>Enable use of bit reservoir when set to 1. Default value is 1. LAME
    3266. 

  3266. has this enabled by default, but can be overridden by use
    3267. 

  3267. &lsquo;<samp>--nores</samp>&rsquo; option.
    3268. 

  3268. </p>
    3269. 

  3269. </dd>
    3270. 

  3270. <dt>&lsquo;<samp>joint_stereo (<em>-m j</em>)</samp>&rsquo;</dt>
    3271. 

  3271. <dd><p>Enable the encoder to use (on a frame by frame basis) either L/R
    3272. 

  3272. stereo or mid/side stereo. Default value is 1.
    3273. 

  3273. </p>
    3274. 

  3274. </dd>
    3275. 

  3275. <dt>&lsquo;<samp>abr (<em>--abr</em>)</samp>&rsquo;</dt>
    3276. 

  3276. <dd><p>Enable the encoder to use ABR when set to 1. The <code>lame</code>
    3277. 

  3277. &lsquo;<samp>--abr</samp>&rsquo; sets the target bitrate, while this options only
    3278. 

  3278. tells FFmpeg to use ABR still relies on &lsquo;<samp>b</samp>&rsquo; to set bitrate.
    3279. 

  3279. </p>
    3280. 

  3280. </dd>
    3281. 

  3281. </dl>
    3282. 

  3282. 

  3283. <a name="libopencore_002damrnb-1"></a>
    3284. 

  3284. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libopencore_002damrnb-1">8.7 libopencore-amrnb</a></h2>
    3285. 

  3285. 

  3286. <p>OpenCORE Adaptive Multi-Rate Narrowband encoder.
    3287. 

  3287. </p>
    3288. 

  3288. <p>Requires the presence of the libopencore-amrnb headers and library during
    3289. 

  3289. configuration. You need to explicitly configure the build with
    3290. 

  3290. <code>--enable-libopencore-amrnb --enable-version3</code>.
    3291. 

  3291. </p>
    3292. 

  3292. <p>This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
    3293. 

  3293. but you can override it by setting &lsquo;<samp>strict</samp>&rsquo; to &lsquo;<samp>unofficial</samp>&rsquo; or
    3294. 

  3294. lower.
    3295. 

  3295. </p>
    3296. 

  3296. <a name="Options-6"></a>
    3297. 

  3297. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-6">8.7.1 Options</a></h3>
    3298. 

  3298. 

  3299. <dl compact="compact">
    3300. 

  3300. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    3301. 

  3301. <dd><p>Set bitrate in bits per second. Only the following bitrates are supported,
    3302. 

  3302. otherwise libavcodec will round to the nearest valid bitrate.
    3303. 

  3303. </p>
    3304. 

  3304. <dl compact="compact">
    3305. 

  3305. <dt>&lsquo;<samp>4750</samp>&rsquo;</dt>
    3306. 

  3306. <dt>&lsquo;<samp>5150</samp>&rsquo;</dt>
    3307. 

  3307. <dt>&lsquo;<samp>5900</samp>&rsquo;</dt>
    3308. 

  3308. <dt>&lsquo;<samp>6700</samp>&rsquo;</dt>
    3309. 

  3309. <dt>&lsquo;<samp>7400</samp>&rsquo;</dt>
    3310. 

  3310. <dt>&lsquo;<samp>7950</samp>&rsquo;</dt>
    3311. 

  3311. <dt>&lsquo;<samp>10200</samp>&rsquo;</dt>
    3312. 

  3312. <dt>&lsquo;<samp>12200</samp>&rsquo;</dt>
    3313. 

  3313. </dl>
    3314. 

  3314. 

  3315. </dd>
    3316. 

  3316. <dt>&lsquo;<samp>dtx</samp>&rsquo;</dt>
    3317. 

  3317. <dd><p>Allow discontinuous transmission (generate comfort noise) when set to 1. The
    3318. 

  3318. default value is 0 (disabled).
    3319. 

  3319. </p>
    3320. 

  3320. </dd>
    3321. 

  3321. </dl>
    3322. 

  3322. 

  3323. <a name="libopus"></a>
    3324. 

  3324. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libopus">8.8 libopus</a></h2>
    3325. 

  3325. 

  3326. <p>libopus Opus Interactive Audio Codec encoder wrapper.
    3327. 

  3327. </p>
    3328. 

  3328. <p>Requires the presence of the libopus headers and library during
    3329. 

  3329. configuration. You need to explicitly configure the build with
    3330. 

  3330. <code>--enable-libopus</code>.
    3331. 

  3331. </p>
    3332. 

  3332. <a name="Option-Mapping"></a>
    3333. 

  3333. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Option-Mapping">8.8.1 Option Mapping</a></h3>
    3334. 

  3334. 

  3335. <p>Most libopus options are modelled after the <code>opusenc</code> utility from
    3336. 

  3336. opus-tools. The following is an option mapping chart describing options
    3337. 

  3337. supported by the libopus wrapper, and their <code>opusenc</code>-equivalent
    3338. 

  3338. in parentheses.
    3339. 

  3339. </p>
    3340. 

  3340. <dl compact="compact">
    3341. 

  3341. <dt>&lsquo;<samp>b (<em>bitrate</em>)</samp>&rsquo;</dt>
    3342. 

  3342. <dd><p>Set the bit rate in bits/s.  FFmpeg&rsquo;s &lsquo;<samp>b</samp>&rsquo; option is
    3343. 

  3343. expressed in bits/s, while <code>opusenc</code>&rsquo;s &lsquo;<samp>bitrate</samp>&rsquo; in
    3344. 

  3344. kilobits/s.
    3345. 

  3345. </p>
    3346. 

  3346. </dd>
    3347. 

  3347. <dt>&lsquo;<samp>vbr (<em>vbr</em>, <em>hard-cbr</em>, and <em>cvbr</em>)</samp>&rsquo;</dt>
    3348. 

  3348. <dd><p>Set VBR mode. The FFmpeg &lsquo;<samp>vbr</samp>&rsquo; option has the following
    3349. 

  3349. valid arguments, with the <code>opusenc</code> equivalent options
    3350. 

  3350. in parentheses:
    3351. 

  3351. </p>
    3352. 

  3352. <dl compact="compact">
    3353. 

  3353. <dt>&lsquo;<samp>off (<em>hard-cbr</em>)</samp>&rsquo;</dt>
    3354. 

  3354. <dd><p>Use constant bit rate encoding.
    3355. 

  3355. </p>
    3356. 

  3356. </dd>
    3357. 

  3357. <dt>&lsquo;<samp>on (<em>vbr</em>)</samp>&rsquo;</dt>
    3358. 

  3358. <dd><p>Use variable bit rate encoding (the default).
    3359. 

  3359. </p>
    3360. 

  3360. </dd>
    3361. 

  3361. <dt>&lsquo;<samp>constrained (<em>cvbr</em>)</samp>&rsquo;</dt>
    3362. 

  3362. <dd><p>Use constrained variable bit rate encoding.
    3363. 

  3363. </p></dd>
    3364. 

  3364. </dl>
    3365. 

  3365. 

  3366. </dd>
    3367. 

  3367. <dt>&lsquo;<samp>compression_level (<em>comp</em>)</samp>&rsquo;</dt>
    3368. 

  3368. <dd><p>Set encoding algorithm complexity. Valid options are integers in
    3369. 

  3369. the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
    3370. 

  3370. gives the highest quality but slowest encoding. The default is 10.
    3371. 

  3371. </p>
    3372. 

  3372. </dd>
    3373. 

  3373. <dt>&lsquo;<samp>frame_duration (<em>framesize</em>)</samp>&rsquo;</dt>
    3374. 

  3374. <dd><p>Set maximum frame size, or duration of a frame in milliseconds. The
    3375. 

  3375. argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
    3376. 

  3376. frame sizes achieve lower latency but less quality at a given bitrate.
    3377. 

  3377. Sizes greater than 20ms are only interesting at fairly low bitrates.
    3378. 

  3378. The default is 20ms.
    3379. 

  3379. </p>
    3380. 

  3380. </dd>
    3381. 

  3381. <dt>&lsquo;<samp>packet_loss (<em>expect-loss</em>)</samp>&rsquo;</dt>
    3382. 

  3382. <dd><p>Set expected packet loss percentage. The default is 0.
    3383. 

  3383. </p>
    3384. 

  3384. </dd>
    3385. 

  3385. <dt>&lsquo;<samp>application (N.A.)</samp>&rsquo;</dt>
    3386. 

  3386. <dd><p>Set intended application type. Valid options are listed below:
    3387. 

  3387. </p>
    3388. 

  3388. <dl compact="compact">
    3389. 

  3389. <dt>&lsquo;<samp>voip</samp>&rsquo;</dt>
    3390. 

  3390. <dd><p>Favor improved speech intelligibility.
    3391. 

  3391. </p></dd>
    3392. 

  3392. <dt>&lsquo;<samp>audio</samp>&rsquo;</dt>
    3393. 

  3393. <dd><p>Favor faithfulness to the input (the default).
    3394. 

  3394. </p></dd>
    3395. 

  3395. <dt>&lsquo;<samp>lowdelay</samp>&rsquo;</dt>
    3396. 

  3396. <dd><p>Restrict to only the lowest delay modes.
    3397. 

  3397. </p></dd>
    3398. 

  3398. </dl>
    3399. 

  3399. 

  3400. </dd>
    3401. 

  3401. <dt>&lsquo;<samp>cutoff (N.A.)</samp>&rsquo;</dt>
    3402. 

  3402. <dd><p>Set cutoff bandwidth in Hz. The argument must be exactly one of the
    3403. 

  3403. following: 4000, 6000, 8000, 12000, or 20000, corresponding to
    3404. 

  3404. narrowband, mediumband, wideband, super wideband, and fullband
    3405. 

  3405. respectively. The default is 0 (cutoff disabled).
    3406. 

  3406. </p>
    3407. 

  3407. </dd>
    3408. 

  3408. <dt>&lsquo;<samp>mapping_family (<em>mapping_family</em>)</samp>&rsquo;</dt>
    3409. 

  3409. <dd><p>Set channel mapping family to be used by the encoder. The default value of -1
    3410. 

  3410. uses mapping family 0 for mono and stereo inputs, and mapping family 1
    3411. 

  3411. otherwise. The default also disables the surround masking and LFE bandwidth
    3412. 

  3412. optimzations in libopus, and requires that the input contains 8 channels or
    3413. 

  3413. fewer.
    3414. 

  3414. </p>
    3415. 

  3415. <p>Other values include 0 for mono and stereo, 1 for surround sound with masking
    3416. 

  3416. and LFE bandwidth optimizations, and 255 for independent streams with an
    3417. 

  3417. unspecified channel layout.
    3418. 

  3418. </p>
    3419. 

  3419. </dd>
    3420. 

  3420. <dt>&lsquo;<samp>apply_phase_inv (N.A.) (requires libopus &gt;= 1.2)</samp>&rsquo;</dt>
    3421. 

  3421. <dd><p>If set to 0, disables the use of phase inversion for intensity stereo,
    3422. 

  3422. improving the quality of mono downmixes, but slightly reducing normal stereo
    3423. 

  3423. quality. The default is 1 (phase inversion enabled).
    3424. 

  3424. </p>
    3425. 

  3425. </dd>
    3426. 

  3426. </dl>
    3427. 

  3427. 

  3428. <p><a name="libshine"></a>
    3429. 

  3429. </p><a name="libshine-1"></a>
    3430. 

  3430. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libshine-1">8.9 libshine</a></h2>
    3431. 

  3431. 

  3432. <p>Shine Fixed-Point MP3 encoder wrapper.
    3433. 

  3433. </p>
    3434. 

  3434. <p>Shine is a fixed-point MP3 encoder. It has a far better performance on
    3435. 

  3435. platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
    3436. 

  3436. However, as it is more targeted on performance than quality, it is not on par
    3437. 

  3437. with LAME and other production-grade encoders quality-wise. Also, according to
    3438. 

  3438. the project&rsquo;s homepage, this encoder may not be free of bugs as the code was
    3439. 

  3439. written a long time ago and the project was dead for at least 5 years.
    3440. 

  3440. </p>
    3441. 

  3441. <p>This encoder only supports stereo and mono input. This is also CBR-only.
    3442. 

  3442. </p>
    3443. 

  3443. <p>The original project (last updated in early 2007) is at
    3444. 

  3444. <a href="http://sourceforge.net/projects/libshine-fxp/">http://sourceforge.net/projects/libshine-fxp/</a>. We only support the
    3445. 

  3445. updated fork by the Savonet/Liquidsoap project at <a href="https://github.com/savonet/shine">https://github.com/savonet/shine</a>.
    3446. 

  3446. </p>
    3447. 

  3447. <p>Requires the presence of the libshine headers and library during
    3448. 

  3448. configuration. You need to explicitly configure the build with
    3449. 

  3449. <code>--enable-libshine</code>.
    3450. 

  3450. </p>
    3451. 

  3451. <p>See also <a href="#libmp3lame">libmp3lame</a>.
    3452. 

  3452. </p>
    3453. 

  3453. <a name="Options-16"></a>
    3454. 

  3454. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-16">8.9.1 Options</a></h3>
    3455. 

  3455. 

  3456. <p>The following options are supported by the libshine wrapper. The
    3457. 

  3457. <code>shineenc</code>-equivalent of the options are listed in parentheses.
    3458. 

  3458. </p>
    3459. 

  3459. <dl compact="compact">
    3460. 

  3460. <dt>&lsquo;<samp>b (<em>-b</em>)</samp>&rsquo;</dt>
    3461. 

  3461. <dd><p>Set bitrate expressed in bits/s for CBR. <code>shineenc</code> &lsquo;<samp>-b</samp>&rsquo; option
    3462. 

  3462. is expressed in kilobits/s.
    3463. 

  3463. </p>
    3464. 

  3464. </dd>
    3465. 

  3465. </dl>
    3466. 

  3466. 

  3467. <a name="libtwolame"></a>
    3468. 

  3468. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libtwolame">8.10 libtwolame</a></h2>
    3469. 

  3469. 

  3470. <p>TwoLAME MP2 encoder wrapper.
    3471. 

  3471. </p>
    3472. 

  3472. <p>Requires the presence of the libtwolame headers and library during
    3473. 

  3473. configuration. You need to explicitly configure the build with
    3474. 

  3474. <code>--enable-libtwolame</code>.
    3475. 

  3475. </p>
    3476. 

  3476. <a name="Options-31"></a>
    3477. 

  3477. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-31">8.10.1 Options</a></h3>
    3478. 

  3478. 

  3479. <p>The following options are supported by the libtwolame wrapper. The
    3480. 

  3480. <code>twolame</code>-equivalent options follow the FFmpeg ones and are in
    3481. 

  3481. parentheses.
    3482. 

  3482. </p>
    3483. 

  3483. <dl compact="compact">
    3484. 

  3484. <dt>&lsquo;<samp>b (<em>-b</em>)</samp>&rsquo;</dt>
    3485. 

  3485. <dd><p>Set bitrate expressed in bits/s for CBR. <code>twolame</code> &lsquo;<samp>b</samp>&rsquo;
    3486. 

  3486. option is expressed in kilobits/s. Default value is 128k.
    3487. 

  3487. </p>
    3488. 

  3488. </dd>
    3489. 

  3489. <dt>&lsquo;<samp>q (<em>-V</em>)</samp>&rsquo;</dt>
    3490. 

  3490. <dd><p>Set quality for experimental VBR support. Maximum value range is
    3491. 

  3491. from -50 to 50, useful range is from -10 to 10. The higher the
    3492. 

  3492. value, the better the quality. This option is valid only using the
    3493. 

  3493. <code>ffmpeg</code> command-line tool. For library interface users,
    3494. 

  3494. use &lsquo;<samp>global_quality</samp>&rsquo;.
    3495. 

  3495. </p>
    3496. 

  3496. </dd>
    3497. 

  3497. <dt>&lsquo;<samp>mode (<em>--mode</em>)</samp>&rsquo;</dt>
    3498. 

  3498. <dd><p>Set the mode of the resulting audio. Possible values:
    3499. 

  3499. </p>
    3500. 

  3500. <dl compact="compact">
    3501. 

  3501. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    3502. 

  3502. <dd><p>Choose mode automatically based on the input. This is the default.
    3503. 

  3503. </p></dd>
    3504. 

  3504. <dt>&lsquo;<samp>stereo</samp>&rsquo;</dt>
    3505. 

  3505. <dd><p>Stereo
    3506. 

  3506. </p></dd>
    3507. 

  3507. <dt>&lsquo;<samp>joint_stereo</samp>&rsquo;</dt>
    3508. 

  3508. <dd><p>Joint stereo
    3509. 

  3509. </p></dd>
    3510. 

  3510. <dt>&lsquo;<samp>dual_channel</samp>&rsquo;</dt>
    3511. 

  3511. <dd><p>Dual channel
    3512. 

  3512. </p></dd>
    3513. 

  3513. <dt>&lsquo;<samp>mono</samp>&rsquo;</dt>
    3514. 

  3514. <dd><p>Mono
    3515. 

  3515. </p></dd>
    3516. 

  3516. </dl>
    3517. 

  3517. 

  3518. </dd>
    3519. 

  3519. <dt>&lsquo;<samp>psymodel (<em>--psyc-mode</em>)</samp>&rsquo;</dt>
    3520. 

  3520. <dd><p>Set psychoacoustic model to use in encoding. The argument must be
    3521. 

  3521. an integer between -1 and 4, inclusive. The higher the value, the
    3522. 

  3522. better the quality. The default value is 3.
    3523. 

  3523. </p>
    3524. 

  3524. </dd>
    3525. 

  3525. <dt>&lsquo;<samp>energy_levels (<em>--energy</em>)</samp>&rsquo;</dt>
    3526. 

  3526. <dd><p>Enable energy levels extensions when set to 1. The default value is
    3527. 

  3527. 0 (disabled).
    3528. 

  3528. </p>
    3529. 

  3529. </dd>
    3530. 

  3530. <dt>&lsquo;<samp>error_protection (<em>--protect</em>)</samp>&rsquo;</dt>
    3531. 

  3531. <dd><p>Enable CRC error protection when set to 1. The default value is 0
    3532. 

  3532. (disabled).
    3533. 

  3533. </p>
    3534. 

  3534. </dd>
    3535. 

  3535. <dt>&lsquo;<samp>copyright (<em>--copyright</em>)</samp>&rsquo;</dt>
    3536. 

  3536. <dd><p>Set MPEG audio copyright flag when set to 1. The default value is 0
    3537. 

  3537. (disabled).
    3538. 

  3538. </p>
    3539. 

  3539. </dd>
    3540. 

  3540. <dt>&lsquo;<samp>original (<em>--original</em>)</samp>&rsquo;</dt>
    3541. 

  3541. <dd><p>Set MPEG audio original flag when set to 1. The default value is 0
    3542. 

  3542. (disabled).
    3543. 

  3543. </p>
    3544. 

  3544. </dd>
    3545. 

  3545. </dl>
    3546. 

  3546. 

  3547. <a name="libvo_002damrwbenc"></a>
    3548. 

  3548. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libvo_002damrwbenc">8.11 libvo-amrwbenc</a></h2>
    3549. 

  3549. 

  3550. <p>VisualOn Adaptive Multi-Rate Wideband encoder.
    3551. 

  3551. </p>
    3552. 

  3552. <p>Requires the presence of the libvo-amrwbenc headers and library during
    3553. 

  3553. configuration. You need to explicitly configure the build with
    3554. 

  3554. <code>--enable-libvo-amrwbenc --enable-version3</code>.
    3555. 

  3555. </p>
    3556. 

  3556. <p>This is a mono-only encoder. Officially it only supports 16000Hz sample
    3557. 

  3557. rate, but you can override it by setting &lsquo;<samp>strict</samp>&rsquo; to
    3558. 

  3558. &lsquo;<samp>unofficial</samp>&rsquo; or lower.
    3559. 

  3559. </p>
    3560. 

  3560. <a name="Options"></a>
    3561. 

  3561. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options">8.11.1 Options</a></h3>
    3562. 

  3562. 

  3563. <dl compact="compact">
    3564. 

  3564. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    3565. 

  3565. <dd><p>Set bitrate in bits/s. Only the following bitrates are supported, otherwise
    3566. 

  3566. libavcodec will round to the nearest valid bitrate.
    3567. 

  3567. </p>
    3568. 

  3568. <dl compact="compact">
    3569. 

  3569. <dt>&lsquo;<samp>6600</samp>&rsquo;</dt>
    3570. 

  3570. <dt>&lsquo;<samp>8850</samp>&rsquo;</dt>
    3571. 

  3571. <dt>&lsquo;<samp>12650</samp>&rsquo;</dt>
    3572. 

  3572. <dt>&lsquo;<samp>14250</samp>&rsquo;</dt>
    3573. 

  3573. <dt>&lsquo;<samp>15850</samp>&rsquo;</dt>
    3574. 

  3574. <dt>&lsquo;<samp>18250</samp>&rsquo;</dt>
    3575. 

  3575. <dt>&lsquo;<samp>19850</samp>&rsquo;</dt>
    3576. 

  3576. <dt>&lsquo;<samp>23050</samp>&rsquo;</dt>
    3577. 

  3577. <dt>&lsquo;<samp>23850</samp>&rsquo;</dt>
    3578. 

  3578. </dl>
    3579. 

  3579. 

  3580. </dd>
    3581. 

  3581. <dt>&lsquo;<samp>dtx</samp>&rsquo;</dt>
    3582. 

  3582. <dd><p>Allow discontinuous transmission (generate comfort noise) when set to 1. The
    3583. 

  3583. default value is 0 (disabled).
    3584. 

  3584. </p>
    3585. 

  3585. </dd>
    3586. 

  3586. </dl>
    3587. 

  3587. 

  3588. <a name="libvorbis"></a>
    3589. 

  3589. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libvorbis">8.12 libvorbis</a></h2>
    3590. 

  3590. 

  3591. <p>libvorbis encoder wrapper.
    3592. 

  3592. </p>
    3593. 

  3593. <p>Requires the presence of the libvorbisenc headers and library during
    3594. 

  3594. configuration. You need to explicitly configure the build with
    3595. 

  3595. <code>--enable-libvorbis</code>.
    3596. 

  3596. </p>
    3597. 

  3597. <a name="Options-7"></a>
    3598. 

  3598. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-7">8.12.1 Options</a></h3>
    3599. 

  3599. 

  3600. <p>The following options are supported by the libvorbis wrapper. The
    3601. 

  3601. <code>oggenc</code>-equivalent of the options are listed in parentheses.
    3602. 

  3602. </p>
    3603. 

  3603. <p>To get a more accurate and extensive documentation of the libvorbis
    3604. 

  3604. options, consult the libvorbisenc&rsquo;s and <code>oggenc</code>&rsquo;s documentations.
    3605. 

  3605. See <a href="http://xiph.org/vorbis/">http://xiph.org/vorbis/</a>,
    3606. 

  3606. <a href="http://wiki.xiph.org/Vorbis-tools">http://wiki.xiph.org/Vorbis-tools</a>, and oggenc(1).
    3607. 

  3607. </p>
    3608. 

  3608. <dl compact="compact">
    3609. 

  3609. <dt>&lsquo;<samp>b (<em>-b</em>)</samp>&rsquo;</dt>
    3610. 

  3610. <dd><p>Set bitrate expressed in bits/s for ABR. <code>oggenc</code> &lsquo;<samp>-b</samp>&rsquo; is
    3611. 

  3611. expressed in kilobits/s.
    3612. 

  3612. </p>
    3613. 

  3613. </dd>
    3614. 

  3614. <dt>&lsquo;<samp>q (<em>-q</em>)</samp>&rsquo;</dt>
    3615. 

  3615. <dd><p>Set constant quality setting for VBR. The value should be a float
    3616. 

  3616. number in the range of -1.0 to 10.0. The higher the value, the better
    3617. 

  3617. the quality. The default value is &lsquo;<samp>3.0</samp>&rsquo;.
    3618. 

  3618. </p>
    3619. 

  3619. <p>This option is valid only using the <code>ffmpeg</code> command-line tool.
    3620. 

  3620. For library interface users, use &lsquo;<samp>global_quality</samp>&rsquo;.
    3621. 

  3621. </p>
    3622. 

  3622. </dd>
    3623. 

  3623. <dt>&lsquo;<samp>cutoff (<em>--advanced-encode-option lowpass_frequency=N</em>)</samp>&rsquo;</dt>
    3624. 

  3624. <dd><p>Set cutoff bandwidth in Hz, a value of 0 disables cutoff. <code>oggenc</code>&rsquo;s
    3625. 

  3625. related option is expressed in kHz. The default value is &lsquo;<samp>0</samp>&rsquo; (cutoff
    3626. 

  3626. disabled).
    3627. 

  3627. </p>
    3628. 

  3628. </dd>
    3629. 

  3629. <dt>&lsquo;<samp>minrate (<em>-m</em>)</samp>&rsquo;</dt>
    3630. 

  3630. <dd><p>Set minimum bitrate expressed in bits/s. <code>oggenc</code> &lsquo;<samp>-m</samp>&rsquo; is
    3631. 

  3631. expressed in kilobits/s.
    3632. 

  3632. </p>
    3633. 

  3633. </dd>
    3634. 

  3634. <dt>&lsquo;<samp>maxrate (<em>-M</em>)</samp>&rsquo;</dt>
    3635. 

  3635. <dd><p>Set maximum bitrate expressed in bits/s. <code>oggenc</code> &lsquo;<samp>-M</samp>&rsquo; is
    3636. 

  3636. expressed in kilobits/s. This only has effect on ABR mode.
    3637. 

  3637. </p>
    3638. 

  3638. </dd>
    3639. 

  3639. <dt>&lsquo;<samp>iblock (<em>--advanced-encode-option impulse_noisetune=N</em>)</samp>&rsquo;</dt>
    3640. 

  3640. <dd><p>Set noise floor bias for impulse blocks. The value is a float number from
    3641. 

  3641. -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
    3642. 

  3642. to the crispness of transients in the encoded audio. The tradeoff for better
    3643. 

  3643. transient response is a higher bitrate.
    3644. 

  3644. </p>
    3645. 

  3645. </dd>
    3646. 

  3646. </dl>
    3647. 

  3647. 

  3648. <p><a name="libwavpack"></a>
    3649. 

  3649. </p><a name="libwavpack-1"></a>
    3650. 

  3650. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libwavpack-1">8.13 libwavpack</a></h2>
    3651. 

  3651. 

  3652. <p>A wrapper providing WavPack encoding through libwavpack.
    3653. 

  3653. </p>
    3654. 

  3654. <p>Only lossless mode using 32-bit integer samples is supported currently.
    3655. 

  3655. </p>
    3656. 

  3656. <p>Requires the presence of the libwavpack headers and library during
    3657. 

  3657. configuration. You need to explicitly configure the build with
    3658. 

  3658. <code>--enable-libwavpack</code>.
    3659. 

  3659. </p>
    3660. 

  3660. <p>Note that a libavcodec-native encoder for the WavPack codec exists so users can
    3661. 

  3661. encode audios with this codec without using this encoder. See <a href="#wavpackenc">wavpackenc</a>.
    3662. 

  3662. </p>
    3663. 

  3663. <a name="Options-35"></a>
    3664. 

  3664. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-35">8.13.1 Options</a></h3>
    3665. 

  3665. 

  3666. <p><code>wavpack</code> command line utility&rsquo;s corresponding options are listed in
    3667. 

  3667. parentheses, if any.
    3668. 

  3668. </p>
    3669. 

  3669. <dl compact="compact">
    3670. 

  3670. <dt>&lsquo;<samp>frame_size (<em>--blocksize</em>)</samp>&rsquo;</dt>
    3671. 

  3671. <dd><p>Default is 32768.
    3672. 

  3672. </p>
    3673. 

  3673. </dd>
    3674. 

  3674. <dt>&lsquo;<samp>compression_level</samp>&rsquo;</dt>
    3675. 

  3675. <dd><p>Set speed vs. compression tradeoff. Acceptable arguments are listed below:
    3676. 

  3676. </p>
    3677. 

  3677. <dl compact="compact">
    3678. 

  3678. <dt>&lsquo;<samp>0 (<em>-f</em>)</samp>&rsquo;</dt>
    3679. 

  3679. <dd><p>Fast mode.
    3680. 

  3680. </p>
    3681. 

  3681. </dd>
    3682. 

  3682. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    3683. 

  3683. <dd><p>Normal (default) settings.
    3684. 

  3684. </p>
    3685. 

  3685. </dd>
    3686. 

  3686. <dt>&lsquo;<samp>2 (<em>-h</em>)</samp>&rsquo;</dt>
    3687. 

  3687. <dd><p>High quality.
    3688. 

  3688. </p>
    3689. 

  3689. </dd>
    3690. 

  3690. <dt>&lsquo;<samp>3 (<em>-hh</em>)</samp>&rsquo;</dt>
    3691. 

  3691. <dd><p>Very high quality.
    3692. 

  3692. </p>
    3693. 

  3693. </dd>
    3694. 

  3694. <dt>&lsquo;<samp>4-8 (<em>-hh -x</em><var>EXTRAPROC</var>)</samp>&rsquo;</dt>
    3695. 

  3695. <dd><p>Same as &lsquo;<samp>3</samp>&rsquo;, but with extra processing enabled.
    3696. 

  3696. </p>
    3697. 

  3697. <p>&lsquo;<samp>4</samp>&rsquo; is the same as &lsquo;<samp>-x2</samp>&rsquo; and &lsquo;<samp>8</samp>&rsquo; is the same as &lsquo;<samp>-x6</samp>&rsquo;.
    3698. 

  3698. </p>
    3699. 

  3699. </dd>
    3700. 

  3700. </dl>
    3701. 

  3701. </dd>
    3702. 

  3702. </dl>
    3703. 

  3703. 

  3704. <p><a name="mjpegenc"></a>
    3705. 

  3705. </p><a name="mjpeg"></a>
    3706. 

  3706. <h2 class="section"><a href="ffmpeg-codecs.html#toc-mjpeg">8.14 mjpeg</a></h2>
    3707. 

  3707. 

  3708. <p>Motion JPEG encoder.
    3709. 

  3709. </p>
    3710. 

  3710. <a name="Options-22"></a>
    3711. 

  3711. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-22">8.14.1 Options</a></h3>
    3712. 

  3712. 

  3713. <dl compact="compact">
    3714. 

  3714. <dt>&lsquo;<samp>huffman</samp>&rsquo;</dt>
    3715. 

  3715. <dd><p>Set the huffman encoding strategy. Possible values:
    3716. 

  3716. </p>
    3717. 

  3717. <dl compact="compact">
    3718. 

  3718. <dt>&lsquo;<samp>default</samp>&rsquo;</dt>
    3719. 

  3719. <dd><p>Use the default huffman tables. This is the default strategy.
    3720. 

  3720. </p>
    3721. 

  3721. </dd>
    3722. 

  3722. <dt>&lsquo;<samp>optimal</samp>&rsquo;</dt>
    3723. 

  3723. <dd><p>Compute and use optimal huffman tables.
    3724. 

  3724. </p>
    3725. 

  3725. </dd>
    3726. 

  3726. </dl>
    3727. 

  3727. </dd>
    3728. 

  3728. </dl>
    3729. 

  3729. 

  3730. <p><a name="wavpackenc"></a>
    3731. 

  3731. </p><a name="wavpack"></a>
    3732. 

  3732. <h2 class="section"><a href="ffmpeg-codecs.html#toc-wavpack">8.15 wavpack</a></h2>
    3733. 

  3733. 

  3734. <p>WavPack lossless audio encoder.
    3735. 

  3735. </p>
    3736. 

  3736. <p>This is a libavcodec-native WavPack encoder. There is also an encoder based on
    3737. 

  3737. libwavpack, but there is virtually no reason to use that encoder.
    3738. 

  3738. </p>
    3739. 

  3739. <p>See also <a href="#libwavpack">libwavpack</a>.
    3740. 

  3740. </p>
    3741. 

  3741. <a name="Options-24"></a>
    3742. 

  3742. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-24">8.15.1 Options</a></h3>
    3743. 

  3743. 

  3744. <p>The equivalent options for <code>wavpack</code> command line utility are listed in
    3745. 

  3745. parentheses.
    3746. 

  3746. </p>
    3747. 

  3747. <a name="Shared-options"></a>
    3748. 

  3748. <h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Shared-options">8.15.1.1 Shared options</a></h4>
    3749. 

  3749. 

  3750. <p>The following shared options are effective for this encoder. Only special notes
    3751. 

  3751. about this particular encoder will be documented here. For the general meaning
    3752. 

  3752. of the options, see <a href="#codec_002doptions">the Codec Options chapter</a>.
    3753. 

  3753. </p>
    3754. 

  3754. <dl compact="compact">
    3755. 

  3755. <dt>&lsquo;<samp>frame_size (<em>--blocksize</em>)</samp>&rsquo;</dt>
    3756. 

  3756. <dd><p>For this encoder, the range for this option is between 128 and 131072. Default
    3757. 

  3757. is automatically decided based on sample rate and number of channel.
    3758. 

  3758. </p>
    3759. 

  3759. <p>For the complete formula of calculating default, see
    3760. 

  3760. &lsquo;<tt>libavcodec/wavpackenc.c</tt>&rsquo;.
    3761. 

  3761. </p>
    3762. 

  3762. </dd>
    3763. 

  3763. <dt>&lsquo;<samp>compression_level (<em>-f</em>, <em>-h</em>, <em>-hh</em>, and <em>-x</em>)</samp>&rsquo;</dt>
    3764. 

  3764. <dd><p>This option&rsquo;s syntax is consistent with <a href="#libwavpack">libwavpack</a>&rsquo;s.
    3765. 

  3765. </p></dd>
    3766. 

  3766. </dl>
    3767. 

  3767. 

  3768. <a name="Private-options"></a>
    3769. 

  3769. <h4 class="subsubsection"><a href="ffmpeg-codecs.html#toc-Private-options">8.15.1.2 Private options</a></h4>
    3770. 

  3770. 

  3771. <dl compact="compact">
    3772. 

  3772. <dt>&lsquo;<samp>joint_stereo (<em>-j</em>)</samp>&rsquo;</dt>
    3773. 

  3773. <dd><p>Set whether to enable joint stereo. Valid values are:
    3774. 

  3774. </p>
    3775. 

  3775. <dl compact="compact">
    3776. 

  3776. <dt>&lsquo;<samp>on (<em>1</em>)</samp>&rsquo;</dt>
    3777. 

  3777. <dd><p>Force mid/side audio encoding.
    3778. 

  3778. </p></dd>
    3779. 

  3779. <dt>&lsquo;<samp>off (<em>0</em>)</samp>&rsquo;</dt>
    3780. 

  3780. <dd><p>Force left/right audio encoding.
    3781. 

  3781. </p></dd>
    3782. 

  3782. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    3783. 

  3783. <dd><p>Let the encoder decide automatically.
    3784. 

  3784. </p></dd>
    3785. 

  3785. </dl>
    3786. 

  3786. 

  3787. </dd>
    3788. 

  3788. <dt>&lsquo;<samp>optimize_mono</samp>&rsquo;</dt>
    3789. 

  3789. <dd><p>Set whether to enable optimization for mono. This option is only effective for
    3790. 

  3790. non-mono streams. Available values:
    3791. 

  3791. </p>
    3792. 

  3792. <dl compact="compact">
    3793. 

  3793. <dt>&lsquo;<samp>on</samp>&rsquo;</dt>
    3794. 

  3794. <dd><p>enabled
    3795. 

  3795. </p></dd>
    3796. 

  3796. <dt>&lsquo;<samp>off</samp>&rsquo;</dt>
    3797. 

  3797. <dd><p>disabled
    3798. 

  3798. </p></dd>
    3799. 

  3799. </dl>
    3800. 

  3800. 

  3801. </dd>
    3802. 

  3802. </dl>
    3803. 

  3803. 

  3804. 

  3805. <a name="Video-Encoders"></a>
    3806. 

  3806. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Video-Encoders">9 Video Encoders</a></h1>
    3807. 

  3807. 

  3808. <p>A description of some of the currently available video encoders
    3809. 

  3809. follows.
    3810. 

  3810. </p>
    3811. 

  3811. <a name="Hap"></a>
    3812. 

  3812. <h2 class="section"><a href="ffmpeg-codecs.html#toc-Hap">9.1 Hap</a></h2>
    3813. 

  3813. 

  3814. <p>Vidvox Hap video encoder.
    3815. 

  3815. </p>
    3816. 

  3816. <a name="Options-26"></a>
    3817. 

  3817. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-26">9.1.1 Options</a></h3>
    3818. 

  3818. 

  3819. <dl compact="compact">
    3820. 

  3820. <dt>&lsquo;<samp>format <var>integer</var></samp>&rsquo;</dt>
    3821. 

  3821. <dd><p>Specifies the Hap format to encode.
    3822. 

  3822. </p>
    3823. 

  3823. <dl compact="compact">
    3824. 

  3824. <dt>&lsquo;<samp>hap</samp>&rsquo;</dt>
    3825. 

  3825. <dt>&lsquo;<samp>hap_alpha</samp>&rsquo;</dt>
    3826. 

  3826. <dt>&lsquo;<samp>hap_q</samp>&rsquo;</dt>
    3827. 

  3827. </dl>
    3828. 

  3828. 

  3829. <p>Default value is &lsquo;<samp>hap</samp>&rsquo;.
    3830. 

  3830. </p>
    3831. 

  3831. </dd>
    3832. 

  3832. <dt>&lsquo;<samp>chunks <var>integer</var></samp>&rsquo;</dt>
    3833. 

  3833. <dd><p>Specifies the number of chunks to split frames into, between 1 and 64. This
    3834. 

  3834. permits multithreaded decoding of large frames, potentially at the cost of
    3835. 

  3835. data-rate. The encoder may modify this value to divide frames evenly.
    3836. 

  3836. </p>
    3837. 

  3837. <p>Default value is <var>1</var>.
    3838. 

  3838. </p>
    3839. 

  3839. </dd>
    3840. 

  3840. <dt>&lsquo;<samp>compressor <var>integer</var></samp>&rsquo;</dt>
    3841. 

  3841. <dd><p>Specifies the second-stage compressor to use. If set to &lsquo;<samp>none</samp>&rsquo;,
    3842. 

  3842. &lsquo;<samp>chunks</samp>&rsquo; will be limited to 1, as chunked uncompressed frames offer no
    3843. 

  3843. benefit.
    3844. 

  3844. </p>
    3845. 

  3845. <dl compact="compact">
    3846. 

  3846. <dt>&lsquo;<samp>none</samp>&rsquo;</dt>
    3847. 

  3847. <dt>&lsquo;<samp>snappy</samp>&rsquo;</dt>
    3848. 

  3848. </dl>
    3849. 

  3849. 

  3850. <p>Default value is &lsquo;<samp>snappy</samp>&rsquo;.
    3851. 

  3851. </p>
    3852. 

  3852. </dd>
    3853. 

  3853. </dl>
    3854. 

  3854. 

  3855. <a name="jpeg2000"></a>
    3856. 

  3856. <h2 class="section"><a href="ffmpeg-codecs.html#toc-jpeg2000">9.2 jpeg2000</a></h2>
    3857. 

  3857. 

  3858. <p>The native jpeg 2000 encoder is lossy by default, the <code>-q:v</code>
    3859. 

  3859. option can be used to set the encoding quality. Lossless encoding
    3860. 

  3860. can be selected with <code>-pred 1</code>.
    3861. 

  3861. </p>
    3862. 

  3862. <a name="Options-17"></a>
    3863. 

  3863. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-17">9.2.1 Options</a></h3>
    3864. 

  3864. 

  3865. <dl compact="compact">
    3866. 

  3866. <dt>&lsquo;<samp>format</samp>&rsquo;</dt>
    3867. 

  3867. <dd><p>Can be set to either <code>j2k</code> or <code>jp2</code> (the default) that
    3868. 

  3868. makes it possible to store non-rgb pix_fmts.
    3869. 

  3869. </p>
    3870. 

  3870. </dd>
    3871. 

  3871. </dl>
    3872. 

  3872. 

  3873. <a name="librav1e"></a>
    3874. 

  3874. <h2 class="section"><a href="ffmpeg-codecs.html#toc-librav1e">9.3 librav1e</a></h2>
    3875. 

  3875. 

  3876. <p>rav1e AV1 encoder wrapper.
    3877. 

  3877. </p>
    3878. 

  3878. <p>Requires the presence of the rav1e headers and library during configuration.
    3879. 

  3879. You need to explicitly configure the build with <code>--enable-librav1e</code>.
    3880. 

  3880. </p>
    3881. 

  3881. <a name="Options-14"></a>
    3882. 

  3882. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-14">9.3.1 Options</a></h3>
    3883. 

  3883. 

  3884. <dl compact="compact">
    3885. 

  3885. <dt>&lsquo;<samp>qmax</samp>&rsquo;</dt>
    3886. 

  3886. <dd><p>Sets the maximum quantizer to use when using bitrate mode.
    3887. 

  3887. </p>
    3888. 

  3888. </dd>
    3889. 

  3889. <dt>&lsquo;<samp>qmin</samp>&rsquo;</dt>
    3890. 

  3890. <dd><p>Sets the minimum quantizer to use when using bitrate mode.
    3891. 

  3891. </p>
    3892. 

  3892. </dd>
    3893. 

  3893. <dt>&lsquo;<samp>qp</samp>&rsquo;</dt>
    3894. 

  3894. <dd><p>Uses quantizer mode to encode at the given quantizer (0-255).
    3895. 

  3895. </p>
    3896. 

  3896. </dd>
    3897. 

  3897. <dt>&lsquo;<samp>speed</samp>&rsquo;</dt>
    3898. 

  3898. <dd><p>Selects the speed preset (0-10) to encode with.
    3899. 

  3899. </p>
    3900. 

  3900. </dd>
    3901. 

  3901. <dt>&lsquo;<samp>tiles</samp>&rsquo;</dt>
    3902. 

  3902. <dd><p>Selects how many tiles to encode with.
    3903. 

  3903. </p>
    3904. 

  3904. </dd>
    3905. 

  3905. <dt>&lsquo;<samp>tile-rows</samp>&rsquo;</dt>
    3906. 

  3906. <dd><p>Selects how many rows of tiles to encode with.
    3907. 

  3907. </p>
    3908. 

  3908. </dd>
    3909. 

  3909. <dt>&lsquo;<samp>tile-columns</samp>&rsquo;</dt>
    3910. 

  3910. <dd><p>Selects how many columns of tiles to encode with.
    3911. 

  3911. </p>
    3912. 

  3912. </dd>
    3913. 

  3913. <dt>&lsquo;<samp>rav1e-params</samp>&rsquo;</dt>
    3914. 

  3914. <dd><p>Set rav1e options using a list of <var>key</var>=<var>value</var> pairs separated
    3915. 

  3915. by &quot;:&quot;. See <code>rav1e --help</code> for a list of options.
    3916. 

  3916. </p>
    3917. 

  3917. <p>For example to specify librav1e encoding options with &lsquo;<samp>-rav1e-params</samp>&rsquo;:
    3918. 

  3918. </p>
    3919. 

  3919. <div class="example">
    3920. 

  3920. <pre class="example">ffmpeg -i input -c:v librav1e -b:v 500K -rav1e-params speed=5:low_latency=true output.mp4
    3921. 

  3921. </pre></div>
    3922. 

  3922. 

  3923. </dd>
    3924. 

  3924. </dl>
    3925. 

  3925. 

  3926. <a name="libaom_002dav1"></a>
    3927. 

  3927. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libaom_002dav1">9.4 libaom-av1</a></h2>
    3928. 

  3928. 

  3929. <p>libaom AV1 encoder wrapper.
    3930. 

  3930. </p>
    3931. 

  3931. <p>Requires the presence of the libaom headers and library during
    3932. 

  3932. configuration.  You need to explicitly configure the build with
    3933. 

  3933. <code>--enable-libaom</code>.
    3934. 

  3934. </p>
    3935. 

  3935. <a name="Options-4"></a>
    3936. 

  3936. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-4">9.4.1 Options</a></h3>
    3937. 

  3937. 

  3938. <p>The wrapper supports the following standard libavcodec options:
    3939. 

  3939. </p>
    3940. 

  3940. <dl compact="compact">
    3941. 

  3941. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    3942. 

  3942. <dd><p>Set bitrate target in bits/second.  By default this will use
    3943. 

  3943. variable-bitrate mode.  If &lsquo;<samp>maxrate</samp>&rsquo; and &lsquo;<samp>minrate</samp>&rsquo; are
    3944. 

  3944. also set to the same value then it will use constant-bitrate mode,
    3945. 

  3945. otherwise if &lsquo;<samp>crf</samp>&rsquo; is set as well then it will use
    3946. 

  3946. constrained-quality mode.
    3947. 

  3947. </p>
    3948. 

  3948. </dd>
    3949. 

  3949. <dt>&lsquo;<samp>g keyint_min</samp>&rsquo;</dt>
    3950. 

  3950. <dd><p>Set key frame placement.  The GOP size sets the maximum distance between
    3951. 

  3951. key frames; if zero the output stream will be intra-only.  The minimum
    3952. 

  3952. distance is ignored unless it is the same as the GOP size, in which case
    3953. 

  3953. key frames will always appear at a fixed interval.  Not set by default,
    3954. 

  3954. so without this option the library has completely free choice about
    3955. 

  3955. where to place key frames.
    3956. 

  3956. </p>
    3957. 

  3957. </dd>
    3958. 

  3958. <dt>&lsquo;<samp>qmin qmax</samp>&rsquo;</dt>
    3959. 

  3959. <dd><p>Set minimum/maximum quantisation values.  Valid range is from 0 to 63
    3960. 

  3960. (warning: this does not match the quantiser values actually used by AV1
    3961. 

  3961. - divide by four to map real quantiser values to this range).  Defaults
    3962. 

  3962. to min/max (no constraint).
    3963. 

  3963. </p>
    3964. 

  3964. </dd>
    3965. 

  3965. <dt>&lsquo;<samp>minrate maxrate bufsize rc_init_occupancy</samp>&rsquo;</dt>
    3966. 

  3966. <dd><p>Set rate control buffering parameters.  Not used if not set - defaults
    3967. 

  3967. to unconstrained variable bitrate.
    3968. 

  3968. </p>
    3969. 

  3969. </dd>
    3970. 

  3970. <dt>&lsquo;<samp>threads</samp>&rsquo;</dt>
    3971. 

  3971. <dd><p>Set the number of threads to use while encoding.  This may require the
    3972. 

  3972. &lsquo;<samp>tiles</samp>&rsquo; or &lsquo;<samp>row-mt</samp>&rsquo; options to also be set to actually
    3973. 

  3973. use the specified number of threads fully. Defaults to the number of
    3974. 

  3974. hardware threads supported by the host machine.
    3975. 

  3975. </p>
    3976. 

  3976. </dd>
    3977. 

  3977. <dt>&lsquo;<samp>profile</samp>&rsquo;</dt>
    3978. 

  3978. <dd><p>Set the encoding profile.  Defaults to using the profile which matches
    3979. 

  3979. the bit depth and chroma subsampling of the input.
    3980. 

  3980. </p>
    3981. 

  3981. </dd>
    3982. 

  3982. </dl>
    3983. 

  3983. 

  3984. <p>The wrapper also has some specific options:
    3985. 

  3985. </p>
    3986. 

  3986. <dl compact="compact">
    3987. 

  3987. <dt>&lsquo;<samp>cpu-used</samp>&rsquo;</dt>
    3988. 

  3988. <dd><p>Set the quality/encoding speed tradeoff.  Valid range is from 0 to 8,
    3989. 

  3989. higher numbers indicating greater speed and lower quality.  The default
    3990. 

  3990. value is 1, which will be slow and high quality.
    3991. 

  3991. </p>
    3992. 

  3992. </dd>
    3993. 

  3993. <dt>&lsquo;<samp>auto-alt-ref</samp>&rsquo;</dt>
    3994. 

  3994. <dd><p>Enable use of alternate reference frames.  Defaults to the internal
    3995. 

  3995. default of the library.
    3996. 

  3996. </p>
    3997. 

  3997. </dd>
    3998. 

  3998. <dt>&lsquo;<samp>arnr-max-frames (<em>frames</em>)</samp>&rsquo;</dt>
    3999. 

  3999. <dd><p>Set altref noise reduction max frame count. Default is -1.
    4000. 

  4000. </p>
    4001. 

  4001. </dd>
    4002. 

  4002. <dt>&lsquo;<samp>arnr-strength (<em>strength</em>)</samp>&rsquo;</dt>
    4003. 

  4003. <dd><p>Set altref noise reduction filter strength. Range is -1 to 6. Default is -1.
    4004. 

  4004. </p>
    4005. 

  4005. </dd>
    4006. 

  4006. <dt>&lsquo;<samp>aq-mode (<em>aq-mode</em>)</samp>&rsquo;</dt>
    4007. 

  4007. <dd><p>Set adaptive quantization mode. Possible values:
    4008. 

  4008. </p>
    4009. 

  4009. <dl compact="compact">
    4010. 

  4010. <dt>&lsquo;<samp>none (<em>0</em>)</samp>&rsquo;</dt>
    4011. 

  4011. <dd><p>Disabled.
    4012. 

  4012. </p>
    4013. 

  4013. </dd>
    4014. 

  4014. <dt>&lsquo;<samp>variance (<em>1</em>)</samp>&rsquo;</dt>
    4015. 

  4015. <dd><p>Variance-based.
    4016. 

  4016. </p>
    4017. 

  4017. </dd>
    4018. 

  4018. <dt>&lsquo;<samp>complexity (<em>2</em>)</samp>&rsquo;</dt>
    4019. 

  4019. <dd><p>Complexity-based.
    4020. 

  4020. </p>
    4021. 

  4021. </dd>
    4022. 

  4022. <dt>&lsquo;<samp>cyclic (<em>3</em>)</samp>&rsquo;</dt>
    4023. 

  4023. <dd><p>Cyclic refresh.
    4024. 

  4024. </p></dd>
    4025. 

  4025. </dl>
    4026. 

  4026. 

  4027. </dd>
    4028. 

  4028. <dt>&lsquo;<samp>tune (<em>tune</em>)</samp>&rsquo;</dt>
    4029. 

  4029. <dd><p>Set the distortion metric the encoder is tuned with. Default is <code>psnr</code>.
    4030. 

  4030. </p>
    4031. 

  4031. <dl compact="compact">
    4032. 

  4032. <dt>&lsquo;<samp>psnr (<em>0</em>)</samp>&rsquo;</dt>
    4033. 

  4033. <dt>&lsquo;<samp>ssim (<em>1</em>)</samp>&rsquo;</dt>
    4034. 

  4034. </dl>
    4035. 

  4035. 

  4036. </dd>
    4037. 

  4037. <dt>&lsquo;<samp>lag-in-frames</samp>&rsquo;</dt>
    4038. 

  4038. <dd><p>Set the maximum number of frames which the encoder may keep in flight
    4039. 

  4039. at any one time for lookahead purposes.  Defaults to the internal
    4040. 

  4040. default of the library.
    4041. 

  4041. </p>
    4042. 

  4042. </dd>
    4043. 

  4043. <dt>&lsquo;<samp>error-resilience</samp>&rsquo;</dt>
    4044. 

  4044. <dd><p>Enable error resilience features:
    4045. 

  4045. </p><dl compact="compact">
    4046. 

  4046. <dt>&lsquo;<samp>default</samp>&rsquo;</dt>
    4047. 

  4047. <dd><p>Improve resilience against losses of whole frames.
    4048. 

  4048. </p></dd>
    4049. 

  4049. </dl>
    4050. 

  4050. <p>Not enabled by default.
    4051. 

  4051. </p>
    4052. 

  4052. </dd>
    4053. 

  4053. <dt>&lsquo;<samp>crf</samp>&rsquo;</dt>
    4054. 

  4054. <dd><p>Set the quality/size tradeoff for constant-quality (no bitrate target)
    4055. 

  4055. and constrained-quality (with maximum bitrate target) modes. Valid
    4056. 

  4056. range is 0 to 63, higher numbers indicating lower quality and smaller
    4057. 

  4057. output size.  Only used if set; by default only the bitrate target is
    4058. 

  4058. used.
    4059. 

  4059. </p>
    4060. 

  4060. </dd>
    4061. 

  4061. <dt>&lsquo;<samp>static-thresh</samp>&rsquo;</dt>
    4062. 

  4062. <dd><p>Set a change threshold on blocks below which they will be skipped by
    4063. 

  4063. the encoder.  Defined in arbitrary units as a nonnegative integer,
    4064. 

  4064. defaulting to zero (no blocks are skipped).
    4065. 

  4065. </p>
    4066. 

  4066. </dd>
    4067. 

  4067. <dt>&lsquo;<samp>drop-threshold</samp>&rsquo;</dt>
    4068. 

  4068. <dd><p>Set a threshold for dropping frames when close to rate control bounds.
    4069. 

  4069. Defined as a percentage of the target buffer - when the rate control
    4070. 

  4070. buffer falls below this percentage, frames will be dropped until it
    4071. 

  4071. has refilled above the threshold.  Defaults to zero (no frames are
    4072. 

  4072. dropped).
    4073. 

  4073. </p>
    4074. 

  4074. </dd>
    4075. 

  4075. <dt>&lsquo;<samp>denoise-noise-level (<em>level</em>)</samp>&rsquo;</dt>
    4076. 

  4076. <dd><p>Amount of noise to be removed for grain synthesis. Grain synthesis is disabled if
    4077. 

  4077. this option is not set or set to 0.
    4078. 

  4078. </p>
    4079. 

  4079. </dd>
    4080. 

  4080. <dt>&lsquo;<samp>denoise-block-size (<em>pixels</em>)</samp>&rsquo;</dt>
    4081. 

  4081. <dd><p>Block size used for denoising for grain synthesis. If not set, AV1 codec
    4082. 

  4082. uses the default value of 32.
    4083. 

  4083. </p>
    4084. 

  4084. </dd>
    4085. 

  4085. <dt>&lsquo;<samp>undershoot-pct (<em>pct</em>)</samp>&rsquo;</dt>
    4086. 

  4086. <dd><p>Set datarate undershoot (min) percentage of the target bitrate. Range is -1 to 100.
    4087. 

  4087. Default is -1.
    4088. 

  4088. </p>
    4089. 

  4089. </dd>
    4090. 

  4090. <dt>&lsquo;<samp>overshoot-pct (<em>pct</em>)</samp>&rsquo;</dt>
    4091. 

  4091. <dd><p>Set datarate overshoot (max) percentage of the target bitrate. Range is -1 to 1000.
    4092. 

  4092. Default is -1.
    4093. 

  4093. </p>
    4094. 

  4094. </dd>
    4095. 

  4095. <dt>&lsquo;<samp>minsection-pct (<em>pct</em>)</samp>&rsquo;</dt>
    4096. 

  4096. <dd><p>Minimum percentage variation of the GOP bitrate from the target bitrate. If minsection-pct
    4097. 

  4097. is not set, the libaomenc wrapper computes it as follows: <code>(minrate * 100 / bitrate)</code>.
    4098. 

  4098. Range is -1 to 100. Default is -1 (unset).
    4099. 

  4099. </p>
    4100. 

  4100. </dd>
    4101. 

  4101. <dt>&lsquo;<samp>maxsection-pct (<em>pct</em>)</samp>&rsquo;</dt>
    4102. 

  4102. <dd><p>Maximum percentage variation of the GOP bitrate from the target bitrate. If maxsection-pct
    4103. 

  4103. is not set, the libaomenc wrapper computes it as follows: <code>(maxrate * 100 / bitrate)</code>.
    4104. 

  4104. Range is -1 to 5000. Default is -1 (unset).
    4105. 

  4105. </p>
    4106. 

  4106. </dd>
    4107. 

  4107. <dt>&lsquo;<samp>frame-parallel (<em>boolean</em>)</samp>&rsquo;</dt>
    4108. 

  4108. <dd><p>Enable frame parallel decodability features. Default is true.
    4109. 

  4109. </p>
    4110. 

  4110. </dd>
    4111. 

  4111. <dt>&lsquo;<samp>tiles</samp>&rsquo;</dt>
    4112. 

  4112. <dd><p>Set the number of tiles to encode the input video with, as columns x
    4113. 

  4113. rows.  Larger numbers allow greater parallelism in both encoding and
    4114. 

  4114. decoding, but may decrease coding efficiency.  Defaults to the minimum
    4115. 

  4115. number of tiles required by the size of the input video (this is 1x1
    4116. 

  4116. (that is, a single tile) for sizes up to and including 4K).
    4117. 

  4117. </p>
    4118. 

  4118. </dd>
    4119. 

  4119. <dt>&lsquo;<samp>tile-columns tile-rows</samp>&rsquo;</dt>
    4120. 

  4120. <dd><p>Set the number of tiles as log2 of the number of tile rows and columns.
    4121. 

  4121. Provided for compatibility with libvpx/VP9.
    4122. 

  4122. </p>
    4123. 

  4123. </dd>
    4124. 

  4124. <dt>&lsquo;<samp>row-mt (Requires libaom &gt;= 1.0.0-759-g90a15f4f2)</samp>&rsquo;</dt>
    4125. 

  4125. <dd><p>Enable row based multi-threading. Disabled by default.
    4126. 

  4126. </p>
    4127. 

  4127. </dd>
    4128. 

  4128. <dt>&lsquo;<samp>enable-cdef (<em>boolean</em>)</samp>&rsquo;</dt>
    4129. 

  4129. <dd><p>Enable Constrained Directional Enhancement Filter. The libaom-av1
    4130. 

  4130. encoder enables CDEF by default.
    4131. 

  4131. </p>
    4132. 

  4132. </dd>
    4133. 

  4133. <dt>&lsquo;<samp>enable-restoration (<em>boolean</em>)</samp>&rsquo;</dt>
    4134. 

  4134. <dd><p>Enable Loop Restoration Filter. Default is true for libaom-av1.
    4135. 

  4135. </p>
    4136. 

  4136. </dd>
    4137. 

  4137. <dt>&lsquo;<samp>enable-global-motion (<em>boolean</em>)</samp>&rsquo;</dt>
    4138. 

  4138. <dd><p>Enable the use of global motion for block prediction. Default is true.
    4139. 

  4139. </p>
    4140. 

  4140. </dd>
    4141. 

  4141. <dt>&lsquo;<samp>enable-intrabc (<em>boolean</em>)</samp>&rsquo;</dt>
    4142. 

  4142. <dd><p>Enable block copy mode for intra block prediction. This mode is
    4143. 

  4143. useful for screen content. Default is true.
    4144. 

  4144. </p>
    4145. 

  4145. </dd>
    4146. 

  4146. </dl>
    4147. 

  4147. 

  4148. <a name="libkvazaar"></a>
    4149. 

  4149. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libkvazaar">9.5 libkvazaar</a></h2>
    4150. 

  4150. 

  4151. <p>Kvazaar H.265/HEVC encoder.
    4152. 

  4152. </p>
    4153. 

  4153. <p>Requires the presence of the libkvazaar headers and library during
    4154. 

  4154. configuration. You need to explicitly configure the build with
    4155. 

  4155. &lsquo;<samp>--enable-libkvazaar</samp>&rsquo;.
    4156. 

  4156. </p>
    4157. 

  4157. <a name="Options-20"></a>
    4158. 

  4158. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-20">9.5.1 Options</a></h3>
    4159. 

  4159. 

  4160. <dl compact="compact">
    4161. 

  4161. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    4162. 

  4162. <dd><p>Set target video bitrate in bit/s and enable rate control.
    4163. 

  4163. </p>
    4164. 

  4164. </dd>
    4165. 

  4165. <dt>&lsquo;<samp>kvazaar-params</samp>&rsquo;</dt>
    4166. 

  4166. <dd><p>Set kvazaar parameters as a list of <var>name</var>=<var>value</var> pairs separated
    4167. 

  4167. by commas (,). See kvazaar documentation for a list of options.
    4168. 

  4168. </p>
    4169. 

  4169. </dd>
    4170. 

  4170. </dl>
    4171. 

  4171. 

  4172. <a name="libopenh264"></a>
    4173. 

  4173. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libopenh264">9.6 libopenh264</a></h2>
    4174. 

  4174. 

  4175. <p>Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
    4176. 

  4176. </p>
    4177. 

  4177. <p>This encoder requires the presence of the libopenh264 headers and
    4178. 

  4178. library during configuration. You need to explicitly configure the
    4179. 

  4179. build with <code>--enable-libopenh264</code>. The library is detected using
    4180. 

  4180. <code>pkg-config</code>.
    4181. 

  4181. </p>
    4182. 

  4182. <p>For more information about the library see
    4183. 

  4183. <a href="http://www.openh264.org">http://www.openh264.org</a>.
    4184. 

  4184. </p>
    4185. 

  4185. <a name="Options-34"></a>
    4186. 

  4186. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-34">9.6.1 Options</a></h3>
    4187. 

  4187. 

  4188. <p>The following FFmpeg global options affect the configurations of the
    4189. 

  4189. libopenh264 encoder.
    4190. 

  4190. </p>
    4191. 

  4191. <dl compact="compact">
    4192. 

  4192. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    4193. 

  4193. <dd><p>Set the bitrate (as a number of bits per second).
    4194. 

  4194. </p>
    4195. 

  4195. </dd>
    4196. 

  4196. <dt>&lsquo;<samp>g</samp>&rsquo;</dt>
    4197. 

  4197. <dd><p>Set the GOP size.
    4198. 

  4198. </p>
    4199. 

  4199. </dd>
    4200. 

  4200. <dt>&lsquo;<samp>maxrate</samp>&rsquo;</dt>
    4201. 

  4201. <dd><p>Set the max bitrate (as a number of bits per second).
    4202. 

  4202. </p>
    4203. 

  4203. </dd>
    4204. 

  4204. <dt>&lsquo;<samp>flags +global_header</samp>&rsquo;</dt>
    4205. 

  4205. <dd><p>Set global header in the bitstream.
    4206. 

  4206. </p>
    4207. 

  4207. </dd>
    4208. 

  4208. <dt>&lsquo;<samp>slices</samp>&rsquo;</dt>
    4209. 

  4209. <dd><p>Set the number of slices, used in parallelized encoding. Default value
    4210. 

  4210. is 0. This is only used when &lsquo;<samp>slice_mode</samp>&rsquo; is set to
    4211. 

  4211. &lsquo;<samp>fixed</samp>&rsquo;.
    4212. 

  4212. </p>
    4213. 

  4213. </dd>
    4214. 

  4214. <dt>&lsquo;<samp>slice_mode</samp>&rsquo;</dt>
    4215. 

  4215. <dd><p>Set slice mode. Can assume one of the following possible values:
    4216. 

  4216. </p>
    4217. 

  4217. <dl compact="compact">
    4218. 

  4218. <dt>&lsquo;<samp>fixed</samp>&rsquo;</dt>
    4219. 

  4219. <dd><p>a fixed number of slices
    4220. 

  4220. </p></dd>
    4221. 

  4221. <dt>&lsquo;<samp>rowmb</samp>&rsquo;</dt>
    4222. 

  4222. <dd><p>one slice per row of macroblocks
    4223. 

  4223. </p></dd>
    4224. 

  4224. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    4225. 

  4225. <dd><p>automatic number of slices according to number of threads
    4226. 

  4226. </p></dd>
    4227. 

  4227. <dt>&lsquo;<samp>dyn</samp>&rsquo;</dt>
    4228. 

  4228. <dd><p>dynamic slicing
    4229. 

  4229. </p></dd>
    4230. 

  4230. </dl>
    4231. 

  4231. 

  4232. <p>Default value is &lsquo;<samp>auto</samp>&rsquo;.
    4233. 

  4233. </p>
    4234. 

  4234. </dd>
    4235. 

  4235. <dt>&lsquo;<samp>loopfilter</samp>&rsquo;</dt>
    4236. 

  4236. <dd><p>Enable loop filter, if set to 1 (automatically enabled). To disable
    4237. 

  4237. set a value of 0.
    4238. 

  4238. </p>
    4239. 

  4239. </dd>
    4240. 

  4240. <dt>&lsquo;<samp>profile</samp>&rsquo;</dt>
    4241. 

  4241. <dd><p>Set profile restrictions. If set to the value of &lsquo;<samp>main</samp>&rsquo; enable
    4242. 

  4242. CABAC (set the <code>SEncParamExt.iEntropyCodingModeFlag</code> flag to 1).
    4243. 

  4243. </p>
    4244. 

  4244. </dd>
    4245. 

  4245. <dt>&lsquo;<samp>max_nal_size</samp>&rsquo;</dt>
    4246. 

  4246. <dd><p>Set maximum NAL size in bytes.
    4247. 

  4247. </p>
    4248. 

  4248. </dd>
    4249. 

  4249. <dt>&lsquo;<samp>allow_skip_frames</samp>&rsquo;</dt>
    4250. 

  4250. <dd><p>Allow skipping frames to hit the target bitrate if set to 1.
    4251. 

  4251. </p></dd>
    4252. 

  4252. </dl>
    4253. 

  4253. 

  4254. <a name="libtheora"></a>
    4255. 

  4255. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libtheora">9.7 libtheora</a></h2>
    4256. 

  4256. 

  4257. <p>libtheora Theora encoder wrapper.
    4258. 

  4258. </p>
    4259. 

  4259. <p>Requires the presence of the libtheora headers and library during
    4260. 

  4260. configuration. You need to explicitly configure the build with
    4261. 

  4261. <code>--enable-libtheora</code>.
    4262. 

  4262. </p>
    4263. 

  4263. <p>For more information about the libtheora project see
    4264. 

  4264. <a href="http://www.theora.org/">http://www.theora.org/</a>.
    4265. 

  4265. </p>
    4266. 

  4266. <a name="Options-30"></a>
    4267. 

  4267. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-30">9.7.1 Options</a></h3>
    4268. 

  4268. 

  4269. <p>The following global options are mapped to internal libtheora options
    4270. 

  4270. which affect the quality and the bitrate of the encoded stream.
    4271. 

  4271. </p>
    4272. 

  4272. <dl compact="compact">
    4273. 

  4273. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    4274. 

  4274. <dd><p>Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode.  In
    4275. 

  4275. case VBR (Variable Bit Rate) mode is enabled this option is ignored.
    4276. 

  4276. </p>
    4277. 

  4277. </dd>
    4278. 

  4278. <dt>&lsquo;<samp>flags</samp>&rsquo;</dt>
    4279. 

  4279. <dd><p>Used to enable constant quality mode (VBR) encoding through the
    4280. 

  4280. &lsquo;<samp>qscale</samp>&rsquo; flag, and to enable the <code>pass1</code> and <code>pass2</code>
    4281. 

  4281. modes.
    4282. 

  4282. </p>
    4283. 

  4283. </dd>
    4284. 

  4284. <dt>&lsquo;<samp>g</samp>&rsquo;</dt>
    4285. 

  4285. <dd><p>Set the GOP size.
    4286. 

  4286. </p>
    4287. 

  4287. </dd>
    4288. 

  4288. <dt>&lsquo;<samp>global_quality</samp>&rsquo;</dt>
    4289. 

  4289. <dd><p>Set the global quality as an integer in lambda units.
    4290. 

  4290. </p>
    4291. 

  4291. <p>Only relevant when VBR mode is enabled with <code>flags +qscale</code>. The
    4292. 

  4292. value is converted to QP units by dividing it by <code>FF_QP2LAMBDA</code>,
    4293. 

  4293. clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
    4294. 

  4294. value in the native libtheora range [0-63]. A higher value corresponds
    4295. 

  4295. to a higher quality.
    4296. 

  4296. </p>
    4297. 

  4297. </dd>
    4298. 

  4298. <dt>&lsquo;<samp>q</samp>&rsquo;</dt>
    4299. 

  4299. <dd><p>Enable VBR mode when set to a non-negative value, and set constant
    4300. 

  4300. quality value as a double floating point value in QP units.
    4301. 

  4301. </p>
    4302. 

  4302. <p>The value is clipped in the [0-10] range, and then multiplied by 6.3
    4303. 

  4303. to get a value in the native libtheora range [0-63].
    4304. 

  4304. </p>
    4305. 

  4305. <p>This option is valid only using the <code>ffmpeg</code> command-line
    4306. 

  4306. tool. For library interface users, use &lsquo;<samp>global_quality</samp>&rsquo;.
    4307. 

  4307. </p></dd>
    4308. 

  4308. </dl>
    4309. 

  4309. 

  4310. <a name="Examples-1"></a>
    4311. 

  4311. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Examples-1">9.7.2 Examples</a></h3>
    4312. 

  4312. 

  4313. <ul>
    4314. 

  4314. <li>
    4315. 

  4315. Set maximum constant quality (VBR) encoding with <code>ffmpeg</code>:
    4316. 

  4316. <div class="example">
    4317. 

  4317. <pre class="example">ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
    4318. 

  4318. </pre></div>
    4319. 

  4319. 

  4320. </li><li>
    4321. 

  4321. Use <code>ffmpeg</code> to convert a CBR 1000 kbps Theora video stream:
    4322. 

  4322. <div class="example">
    4323. 

  4323. <pre class="example">ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
    4324. 

  4324. </pre></div>
    4325. 

  4325. </li></ul>
    4326. 

  4326. 

  4327. <a name="libvpx"></a>
    4328. 

  4328. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libvpx">9.8 libvpx</a></h2>
    4329. 

  4329. 

  4330. <p>VP8/VP9 format supported through libvpx.
    4331. 

  4331. </p>
    4332. 

  4332. <p>Requires the presence of the libvpx headers and library during configuration.
    4333. 

  4333. You need to explicitly configure the build with <code>--enable-libvpx</code>.
    4334. 

  4334. </p>
    4335. 

  4335. <a name="Options-9"></a>
    4336. 

  4336. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-9">9.8.1 Options</a></h3>
    4337. 

  4337. 

  4338. <p>The following options are supported by the libvpx wrapper. The
    4339. 

  4339. <code>vpxenc</code>-equivalent options or values are listed in parentheses
    4340. 

  4340. for easy migration.
    4341. 

  4341. </p>
    4342. 

  4342. <p>To reduce the duplication of documentation, only the private options
    4343. 

  4343. and some others requiring special attention are documented here. For
    4344. 

  4344. the documentation of the undocumented generic options, see
    4345. 

  4345. <a href="#codec_002doptions">the Codec Options chapter</a>.
    4346. 

  4346. </p>
    4347. 

  4347. <p>To get more documentation of the libvpx options, invoke the command
    4348. 

  4348. <code>ffmpeg -h encoder=libvpx</code>, <code>ffmpeg -h encoder=libvpx-vp9</code> or
    4349. 

  4349. <code>vpxenc --help</code>. Further information is available in the libvpx API
    4350. 

  4350. documentation.
    4351. 

  4351. </p>
    4352. 

  4352. <dl compact="compact">
    4353. 

  4353. <dt>&lsquo;<samp>b (<em>target-bitrate</em>)</samp>&rsquo;</dt>
    4354. 

  4354. <dd><p>Set bitrate in bits/s. Note that FFmpeg&rsquo;s &lsquo;<samp>b</samp>&rsquo; option is
    4355. 

  4355. expressed in bits/s, while <code>vpxenc</code>&rsquo;s &lsquo;<samp>target-bitrate</samp>&rsquo; is in
    4356. 

  4356. kilobits/s.
    4357. 

  4357. </p>
    4358. 

  4358. </dd>
    4359. 

  4359. <dt>&lsquo;<samp>g (<em>kf-max-dist</em>)</samp>&rsquo;</dt>
    4360. 

  4360. <dt>&lsquo;<samp>keyint_min (<em>kf-min-dist</em>)</samp>&rsquo;</dt>
    4361. 

  4361. <dt>&lsquo;<samp>qmin (<em>min-q</em>)</samp>&rsquo;</dt>
    4362. 

  4362. <dt>&lsquo;<samp>qmax (<em>max-q</em>)</samp>&rsquo;</dt>
    4363. 

  4363. <dt>&lsquo;<samp>bufsize (<em>buf-sz</em>, <em>buf-optimal-sz</em>)</samp>&rsquo;</dt>
    4364. 

  4364. <dd><p>Set ratecontrol buffer size (in bits). Note <code>vpxenc</code>&rsquo;s options are
    4365. 

  4365. specified in milliseconds, the libvpx wrapper converts this value as follows:
    4366. 

  4366. <code>buf-sz = bufsize * 1000 / bitrate</code>,
    4367. 

  4367. <code>buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6</code>.
    4368. 

  4368. </p>
    4369. 

  4369. </dd>
    4370. 

  4370. <dt>&lsquo;<samp>rc_init_occupancy (<em>buf-initial-sz</em>)</samp>&rsquo;</dt>
    4371. 

  4371. <dd><p>Set number of bits which should be loaded into the rc buffer before decoding
    4372. 

  4372. starts. Note <code>vpxenc</code>&rsquo;s option is specified in milliseconds, the libvpx
    4373. 

  4373. wrapper converts this value as follows:
    4374. 

  4374. <code>rc_init_occupancy * 1000 / bitrate</code>.
    4375. 

  4375. </p>
    4376. 

  4376. </dd>
    4377. 

  4377. <dt>&lsquo;<samp>undershoot-pct</samp>&rsquo;</dt>
    4378. 

  4378. <dd><p>Set datarate undershoot (min) percentage of the target bitrate.
    4379. 

  4379. </p>
    4380. 

  4380. </dd>
    4381. 

  4381. <dt>&lsquo;<samp>overshoot-pct</samp>&rsquo;</dt>
    4382. 

  4382. <dd><p>Set datarate overshoot (max) percentage of the target bitrate.
    4383. 

  4383. </p>
    4384. 

  4384. </dd>
    4385. 

  4385. <dt>&lsquo;<samp>skip_threshold (<em>drop-frame</em>)</samp>&rsquo;</dt>
    4386. 

  4386. <dt>&lsquo;<samp>qcomp (<em>bias-pct</em>)</samp>&rsquo;</dt>
    4387. 

  4387. <dt>&lsquo;<samp>maxrate (<em>maxsection-pct</em>)</samp>&rsquo;</dt>
    4388. 

  4388. <dd><p>Set GOP max bitrate in bits/s. Note <code>vpxenc</code>&rsquo;s option is specified as a
    4389. 

  4389. percentage of the target bitrate, the libvpx wrapper converts this value as
    4390. 

  4390. follows: <code>(maxrate * 100 / bitrate)</code>.
    4391. 

  4391. </p>
    4392. 

  4392. </dd>
    4393. 

  4393. <dt>&lsquo;<samp>minrate (<em>minsection-pct</em>)</samp>&rsquo;</dt>
    4394. 

  4394. <dd><p>Set GOP min bitrate in bits/s. Note <code>vpxenc</code>&rsquo;s option is specified as a
    4395. 

  4395. percentage of the target bitrate, the libvpx wrapper converts this value as
    4396. 

  4396. follows: <code>(minrate * 100 / bitrate)</code>.
    4397. 

  4397. </p>
    4398. 

  4398. </dd>
    4399. 

  4399. <dt>&lsquo;<samp>minrate, maxrate, b <em>end-usage=cbr</em></samp>&rsquo;</dt>
    4400. 

  4400. <dd><p><code>(minrate == maxrate == bitrate)</code>.
    4401. 

  4401. </p>
    4402. 

  4402. </dd>
    4403. 

  4403. <dt>&lsquo;<samp>crf (<em>end-usage=cq</em>, <em>cq-level</em>)</samp>&rsquo;</dt>
    4404. 

  4404. <dt>&lsquo;<samp>tune (<em>tune</em>)</samp>&rsquo;</dt>
    4405. 

  4405. <dd><dl compact="compact">
    4406. 

  4406. <dt>&lsquo;<samp>psnr (<em>psnr</em>)</samp>&rsquo;</dt>
    4407. 

  4407. <dt>&lsquo;<samp>ssim (<em>ssim</em>)</samp>&rsquo;</dt>
    4408. 

  4408. </dl>
    4409. 

  4409. 

  4410. </dd>
    4411. 

  4411. <dt>&lsquo;<samp>quality, deadline (<em>deadline</em>)</samp>&rsquo;</dt>
    4412. 

  4412. <dd><dl compact="compact">
    4413. 

  4413. <dt>&lsquo;<samp>best</samp>&rsquo;</dt>
    4414. 

  4414. <dd><p>Use best quality deadline. Poorly named and quite slow, this option should be
    4415. 

  4415. avoided as it may give worse quality output than good.
    4416. 

  4416. </p></dd>
    4417. 

  4417. <dt>&lsquo;<samp>good</samp>&rsquo;</dt>
    4418. 

  4418. <dd><p>Use good quality deadline. This is a good trade-off between speed and quality
    4419. 

  4419. when used with the &lsquo;<samp>cpu-used</samp>&rsquo; option.
    4420. 

  4420. </p></dd>
    4421. 

  4421. <dt>&lsquo;<samp>realtime</samp>&rsquo;</dt>
    4422. 

  4422. <dd><p>Use realtime quality deadline.
    4423. 

  4423. </p></dd>
    4424. 

  4424. </dl>
    4425. 

  4425. 

  4426. </dd>
    4427. 

  4427. <dt>&lsquo;<samp>speed, cpu-used (<em>cpu-used</em>)</samp>&rsquo;</dt>
    4428. 

  4428. <dd><p>Set quality/speed ratio modifier. Higher values speed up the encode at the cost
    4429. 

  4429. of quality.
    4430. 

  4430. </p>
    4431. 

  4431. </dd>
    4432. 

  4432. <dt>&lsquo;<samp>nr (<em>noise-sensitivity</em>)</samp>&rsquo;</dt>
    4433. 

  4433. <dt>&lsquo;<samp>static-thresh</samp>&rsquo;</dt>
    4434. 

  4434. <dd><p>Set a change threshold on blocks below which they will be skipped by the
    4435. 

  4435. encoder.
    4436. 

  4436. </p>
    4437. 

  4437. </dd>
    4438. 

  4438. <dt>&lsquo;<samp>slices (<em>token-parts</em>)</samp>&rsquo;</dt>
    4439. 

  4439. <dd><p>Note that FFmpeg&rsquo;s &lsquo;<samp>slices</samp>&rsquo; option gives the total number of partitions,
    4440. 

  4440. while <code>vpxenc</code>&rsquo;s &lsquo;<samp>token-parts</samp>&rsquo; is given as
    4441. 

  4441. <code>log2(partitions)</code>.
    4442. 

  4442. </p>
    4443. 

  4443. </dd>
    4444. 

  4444. <dt>&lsquo;<samp>max-intra-rate</samp>&rsquo;</dt>
    4445. 

  4445. <dd><p>Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
    4446. 

  4446. means unlimited.
    4447. 

  4447. </p>
    4448. 

  4448. </dd>
    4449. 

  4449. <dt>&lsquo;<samp>force_key_frames</samp>&rsquo;</dt>
    4450. 

  4450. <dd><p><code>VPX_EFLAG_FORCE_KF</code>
    4451. 

  4451. </p>
    4452. 

  4452. </dd>
    4453. 

  4453. <dt>&lsquo;<samp>Alternate reference frame related</samp>&rsquo;</dt>
    4454. 

  4454. <dd><dl compact="compact">
    4455. 

  4455. <dt>&lsquo;<samp>auto-alt-ref</samp>&rsquo;</dt>
    4456. 

  4456. <dd><p>Enable use of alternate reference frames (2-pass only).
    4457. 

  4457. Values greater than 1 enable multi-layer alternate reference frames (VP9 only).
    4458. 

  4458. </p></dd>
    4459. 

  4459. <dt>&lsquo;<samp>arnr-maxframes</samp>&rsquo;</dt>
    4460. 

  4460. <dd><p>Set altref noise reduction max frame count.
    4461. 

  4461. </p></dd>
    4462. 

  4462. <dt>&lsquo;<samp>arnr-type</samp>&rsquo;</dt>
    4463. 

  4463. <dd><p>Set altref noise reduction filter type: backward, forward, centered.
    4464. 

  4464. </p></dd>
    4465. 

  4465. <dt>&lsquo;<samp>arnr-strength</samp>&rsquo;</dt>
    4466. 

  4466. <dd><p>Set altref noise reduction filter strength.
    4467. 

  4467. </p></dd>
    4468. 

  4468. <dt>&lsquo;<samp>rc-lookahead, lag-in-frames (<em>lag-in-frames</em>)</samp>&rsquo;</dt>
    4469. 

  4469. <dd><p>Set number of frames to look ahead for frametype and ratecontrol.
    4470. 

  4470. </p></dd>
    4471. 

  4471. </dl>
    4472. 

  4472. 

  4473. </dd>
    4474. 

  4474. <dt>&lsquo;<samp>error-resilient</samp>&rsquo;</dt>
    4475. 

  4475. <dd><p>Enable error resiliency features.
    4476. 

  4476. </p>
    4477. 

  4477. </dd>
    4478. 

  4478. <dt>&lsquo;<samp>sharpness <var>integer</var></samp>&rsquo;</dt>
    4479. 

  4479. <dd><p>Increase sharpness at the expense of lower PSNR.
    4480. 

  4480. The valid range is [0, 7].
    4481. 

  4481. </p>
    4482. 

  4482. </dd>
    4483. 

  4483. <dt>&lsquo;<samp>ts-parameters</samp>&rsquo;</dt>
    4484. 

  4484. <dd><p>Sets the temporal scalability configuration using a :-separated list of
    4485. 

  4485. key=value pairs. For example, to specify temporal scalability parameters
    4486. 

  4486. with <code>ffmpeg</code>:
    4487. 

  4487. </p><div class="example">
    4488. 

  4488. <pre class="example">ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\
    4489. 

  4489. ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\
    4490. 

  4490. ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT
    4491. 

  4491. </pre></div>
    4492. 

  4492. <p>Below is a brief explanation of each of the parameters, please
    4493. 

  4493. refer to <code>struct vpx_codec_enc_cfg</code> in <code>vpx/vpx_encoder.h</code> for more
    4494. 

  4494. details.
    4495. 

  4495. </p><dl compact="compact">
    4496. 

  4496. <dt>&lsquo;<samp>ts_number_layers</samp>&rsquo;</dt>
    4497. 

  4497. <dd><p>Number of temporal coding layers.
    4498. 

  4498. </p></dd>
    4499. 

  4499. <dt>&lsquo;<samp>ts_target_bitrate</samp>&rsquo;</dt>
    4500. 

  4500. <dd><p>Target bitrate for each temporal layer (in kbps).
    4501. 

  4501. (bitrate should be inclusive of the lower temporal layer).
    4502. 

  4502. </p></dd>
    4503. 

  4503. <dt>&lsquo;<samp>ts_rate_decimator</samp>&rsquo;</dt>
    4504. 

  4504. <dd><p>Frame rate decimation factor for each temporal layer.
    4505. 

  4505. </p></dd>
    4506. 

  4506. <dt>&lsquo;<samp>ts_periodicity</samp>&rsquo;</dt>
    4507. 

  4507. <dd><p>Length of the sequence defining frame temporal layer membership.
    4508. 

  4508. </p></dd>
    4509. 

  4509. <dt>&lsquo;<samp>ts_layer_id</samp>&rsquo;</dt>
    4510. 

  4510. <dd><p>Template defining the membership of frames to temporal layers.
    4511. 

  4511. </p></dd>
    4512. 

  4512. <dt>&lsquo;<samp>ts_layering_mode</samp>&rsquo;</dt>
    4513. 

  4513. <dd><p>(optional) Selecting the temporal structure from a set of pre-defined temporal layering modes.
    4514. 

  4514. Currently supports the following options.
    4515. 

  4515. </p><dl compact="compact">
    4516. 

  4516. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    4517. 

  4517. <dd><p>No temporal layering flags are provided internally,
    4518. 

  4518. relies on flags being passed in using <code>metadata</code> field in <code>AVFrame</code>
    4519. 

  4519. with following keys.
    4520. 

  4520. </p><dl compact="compact">
    4521. 

  4521. <dt>&lsquo;<samp>vp8-flags</samp>&rsquo;</dt>
    4522. 

  4522. <dd><p>Sets the flags passed into the encoder to indicate the referencing scheme for
    4523. 

  4523. the current frame.
    4524. 

  4524. Refer to function <code>vpx_codec_encode</code> in <code>vpx/vpx_encoder.h</code> for more
    4525. 

  4525. details.
    4526. 

  4526. </p></dd>
    4527. 

  4527. <dt>&lsquo;<samp>temporal_id</samp>&rsquo;</dt>
    4528. 

  4528. <dd><p>Explicitly sets the temporal id of the current frame to encode.
    4529. 

  4529. </p></dd>
    4530. 

  4530. </dl>
    4531. 

  4531. </dd>
    4532. 

  4532. <dt>&lsquo;<samp>2</samp>&rsquo;</dt>
    4533. 

  4533. <dd><p>Two temporal layers. 0-1...
    4534. 

  4534. </p></dd>
    4535. 

  4535. <dt>&lsquo;<samp>3</samp>&rsquo;</dt>
    4536. 

  4536. <dd><p>Three temporal layers. 0-2-1-2...; with single reference frame.
    4537. 

  4537. </p></dd>
    4538. 

  4538. <dt>&lsquo;<samp>4</samp>&rsquo;</dt>
    4539. 

  4539. <dd><p>Same as option &quot;3&quot;, except there is a dependency between
    4540. 

  4540. the two temporal layer 2 frames within the temporal period.
    4541. 

  4541. </p></dd>
    4542. 

  4542. </dl>
    4543. 

  4543. </dd>
    4544. 

  4544. </dl>
    4545. 

  4545. 

  4546. </dd>
    4547. 

  4547. <dt>&lsquo;<samp>VP9-specific options</samp>&rsquo;</dt>
    4548. 

  4548. <dd><dl compact="compact">
    4549. 

  4549. <dt>&lsquo;<samp>lossless</samp>&rsquo;</dt>
    4550. 

  4550. <dd><p>Enable lossless mode.
    4551. 

  4551. </p></dd>
    4552. 

  4552. <dt>&lsquo;<samp>tile-columns</samp>&rsquo;</dt>
    4553. 

  4553. <dd><p>Set number of tile columns to use. Note this is given as
    4554. 

  4554. <code>log2(tile_columns)</code>. For example, 8 tile columns would be requested by
    4555. 

  4555. setting the &lsquo;<samp>tile-columns</samp>&rsquo; option to 3.
    4556. 

  4556. </p></dd>
    4557. 

  4557. <dt>&lsquo;<samp>tile-rows</samp>&rsquo;</dt>
    4558. 

  4558. <dd><p>Set number of tile rows to use. Note this is given as <code>log2(tile_rows)</code>.
    4559. 

  4559. For example, 4 tile rows would be requested by setting the &lsquo;<samp>tile-rows</samp>&rsquo;
    4560. 

  4560. option to 2.
    4561. 

  4561. </p></dd>
    4562. 

  4562. <dt>&lsquo;<samp>frame-parallel</samp>&rsquo;</dt>
    4563. 

  4563. <dd><p>Enable frame parallel decodability features.
    4564. 

  4564. </p></dd>
    4565. 

  4565. <dt>&lsquo;<samp>aq-mode</samp>&rsquo;</dt>
    4566. 

  4566. <dd><p>Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
    4567. 

  4567. cyclic refresh, 4: equator360).
    4568. 

  4568. </p></dd>
    4569. 

  4569. <dt>&lsquo;<samp>colorspace <em>color-space</em></samp>&rsquo;</dt>
    4570. 

  4570. <dd><p>Set input color space. The VP9 bitstream supports signaling the following
    4571. 

  4571. colorspaces:
    4572. 

  4572. </p><dl compact="compact">
    4573. 

  4573. <dt>&lsquo;<samp>&lsquo;<samp>rgb</samp>&rsquo; <em>sRGB</em></samp>&rsquo;</dt>
    4574. 

  4574. <dt>&lsquo;<samp>&lsquo;<samp>bt709</samp>&rsquo; <em>bt709</em></samp>&rsquo;</dt>
    4575. 

  4575. <dt>&lsquo;<samp>&lsquo;<samp>unspecified</samp>&rsquo; <em>unknown</em></samp>&rsquo;</dt>
    4576. 

  4576. <dt>&lsquo;<samp>&lsquo;<samp>bt470bg</samp>&rsquo; <em>bt601</em></samp>&rsquo;</dt>
    4577. 

  4577. <dt>&lsquo;<samp>&lsquo;<samp>smpte170m</samp>&rsquo; <em>smpte170</em></samp>&rsquo;</dt>
    4578. 

  4578. <dt>&lsquo;<samp>&lsquo;<samp>smpte240m</samp>&rsquo; <em>smpte240</em></samp>&rsquo;</dt>
    4579. 

  4579. <dt>&lsquo;<samp>&lsquo;<samp>bt2020_ncl</samp>&rsquo; <em>bt2020</em></samp>&rsquo;</dt>
    4580. 

  4580. </dl>
    4581. 

  4581. </dd>
    4582. 

  4582. <dt>&lsquo;<samp>row-mt <var>boolean</var></samp>&rsquo;</dt>
    4583. 

  4583. <dd><p>Enable row based multi-threading.
    4584. 

  4584. </p></dd>
    4585. 

  4585. <dt>&lsquo;<samp>tune-content</samp>&rsquo;</dt>
    4586. 

  4586. <dd><p>Set content type: default (0), screen (1), film (2).
    4587. 

  4587. </p></dd>
    4588. 

  4588. <dt>&lsquo;<samp>corpus-complexity</samp>&rsquo;</dt>
    4589. 

  4589. <dd><p>Corpus VBR mode is a variant of standard VBR where the complexity distribution
    4590. 

  4590. midpoint is passed in rather than calculated for a specific clip or chunk.
    4591. 

  4591. </p>
    4592. 

  4592. <p>The valid range is [0, 10000]. 0 (default) uses standard VBR.
    4593. 

  4593. </p></dd>
    4594. 

  4594. <dt>&lsquo;<samp>enable-tpl <var>boolean</var></samp>&rsquo;</dt>
    4595. 

  4595. <dd><p>Enable temporal dependency model.
    4596. 

  4596. </p></dd>
    4597. 

  4597. </dl>
    4598. 

  4598. 

  4599. </dd>
    4600. 

  4600. </dl>
    4601. 

  4601. 

  4602. <p>For more information about libvpx see:
    4603. 

  4603. <a href="http://www.webmproject.org/">http://www.webmproject.org/</a>
    4604. 

  4604. </p>
    4605. 

  4605. <a name="libwebp"></a>
    4606. 

  4606. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libwebp">9.9 libwebp</a></h2>
    4607. 

  4607. 

  4608. <p>libwebp WebP Image encoder wrapper
    4609. 

  4609. </p>
    4610. 

  4610. <p>libwebp is Google&rsquo;s official encoder for WebP images. It can encode in either
    4611. 

  4611. lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
    4612. 

  4612. frame. Lossless images are a separate codec developed by Google.
    4613. 

  4613. </p>
    4614. 

  4614. <a name="Pixel-Format"></a>
    4615. 

  4615. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Pixel-Format">9.9.1 Pixel Format</a></h3>
    4616. 

  4616. 

  4617. <p>Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
    4618. 

  4618. to limitations of the format and libwebp. Alpha is supported for either mode.
    4619. 

  4619. Because of API limitations, if RGB is passed in when encoding lossy or YUV is
    4620. 

  4620. passed in for encoding lossless, the pixel format will automatically be
    4621. 

  4621. converted using functions from libwebp. This is not ideal and is done only for
    4622. 

  4622. convenience.
    4623. 

  4623. </p>
    4624. 

  4624. <a name="Options-28"></a>
    4625. 

  4625. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-28">9.9.2 Options</a></h3>
    4626. 

  4626. 

  4627. <dl compact="compact">
    4628. 

  4628. <dt>&lsquo;<samp>-lossless <var>boolean</var></samp>&rsquo;</dt>
    4629. 

  4629. <dd><p>Enables/Disables use of lossless mode. Default is 0.
    4630. 

  4630. </p>
    4631. 

  4631. </dd>
    4632. 

  4632. <dt>&lsquo;<samp>-compression_level <var>integer</var></samp>&rsquo;</dt>
    4633. 

  4633. <dd><p>For lossy, this is a quality/speed tradeoff. Higher values give better quality
    4634. 

  4634. for a given size at the cost of increased encoding time. For lossless, this is
    4635. 

  4635. a size/speed tradeoff. Higher values give smaller size at the cost of increased
    4636. 

  4636. encoding time. More specifically, it controls the number of extra algorithms
    4637. 

  4637. and compression tools used, and varies the combination of these tools. This
    4638. 

  4638. maps to the <var>method</var> option in libwebp. The valid range is 0 to 6.
    4639. 

  4639. Default is 4.
    4640. 

  4640. </p>
    4641. 

  4641. </dd>
    4642. 

  4642. <dt>&lsquo;<samp>-qscale <var>float</var></samp>&rsquo;</dt>
    4643. 

  4643. <dd><p>For lossy encoding, this controls image quality, 0 to 100. For lossless
    4644. 

  4644. encoding, this controls the effort and time spent at compressing more. The
    4645. 

  4645. default value is 75. Note that for usage via libavcodec, this option is called
    4646. 

  4646. <var>global_quality</var> and must be multiplied by <var>FF_QP2LAMBDA</var>.
    4647. 

  4647. </p>
    4648. 

  4648. </dd>
    4649. 

  4649. <dt>&lsquo;<samp>-preset <var>type</var></samp>&rsquo;</dt>
    4650. 

  4650. <dd><p>Configuration preset. This does some automatic settings based on the general
    4651. 

  4651. type of the image.
    4652. 

  4652. </p><dl compact="compact">
    4653. 

  4653. <dt>&lsquo;<samp>none</samp>&rsquo;</dt>
    4654. 

  4654. <dd><p>Do not use a preset.
    4655. 

  4655. </p></dd>
    4656. 

  4656. <dt>&lsquo;<samp>default</samp>&rsquo;</dt>
    4657. 

  4657. <dd><p>Use the encoder default.
    4658. 

  4658. </p></dd>
    4659. 

  4659. <dt>&lsquo;<samp>picture</samp>&rsquo;</dt>
    4660. 

  4660. <dd><p>Digital picture, like portrait, inner shot
    4661. 

  4661. </p></dd>
    4662. 

  4662. <dt>&lsquo;<samp>photo</samp>&rsquo;</dt>
    4663. 

  4663. <dd><p>Outdoor photograph, with natural lighting
    4664. 

  4664. </p></dd>
    4665. 

  4665. <dt>&lsquo;<samp>drawing</samp>&rsquo;</dt>
    4666. 

  4666. <dd><p>Hand or line drawing, with high-contrast details
    4667. 

  4667. </p></dd>
    4668. 

  4668. <dt>&lsquo;<samp>icon</samp>&rsquo;</dt>
    4669. 

  4669. <dd><p>Small-sized colorful images
    4670. 

  4670. </p></dd>
    4671. 

  4671. <dt>&lsquo;<samp>text</samp>&rsquo;</dt>
    4672. 

  4672. <dd><p>Text-like
    4673. 

  4673. </p></dd>
    4674. 

  4674. </dl>
    4675. 

  4675. 

  4676. </dd>
    4677. 

  4677. </dl>
    4678. 

  4678. 

  4679. <a name="libx264_002c-libx264rgb"></a>
    4680. 

  4680. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libx264_002c-libx264rgb">9.10 libx264, libx264rgb</a></h2>
    4681. 

  4681. 

  4682. <p>x264 H.264/MPEG-4 AVC encoder wrapper.
    4683. 

  4683. </p>
    4684. 

  4684. <p>This encoder requires the presence of the libx264 headers and library
    4685. 

  4685. during configuration. You need to explicitly configure the build with
    4686. 

  4686. <code>--enable-libx264</code>.
    4687. 

  4687. </p>
    4688. 

  4688. <p>libx264 supports an impressive number of features, including 8x8 and
    4689. 

  4689. 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
    4690. 

  4690. entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
    4691. 

  4691. for detail retention (adaptive quantization, psy-RD, psy-trellis).
    4692. 

  4692. </p>
    4693. 

  4693. <p>Many libx264 encoder options are mapped to FFmpeg global codec
    4694. 

  4694. options, while unique encoder options are provided through private
    4695. 

  4695. options. Additionally the &lsquo;<samp>x264opts</samp>&rsquo; and &lsquo;<samp>x264-params</samp>&rsquo;
    4696. 

  4696. private options allows one to pass a list of key=value tuples as accepted
    4697. 

  4697. by the libx264 <code>x264_param_parse</code> function.
    4698. 

  4698. </p>
    4699. 

  4699. <p>The x264 project website is at
    4700. 

  4700. <a href="http://www.videolan.org/developers/x264.html">http://www.videolan.org/developers/x264.html</a>.
    4701. 

  4701. </p>
    4702. 

  4702. <p>The libx264rgb encoder is the same as libx264, except it accepts packed RGB
    4703. 

  4703. pixel formats as input instead of YUV.
    4704. 

  4704. </p>
    4705. 

  4705. <a name="Supported-Pixel-Formats"></a>
    4706. 

  4706. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Supported-Pixel-Formats">9.10.1 Supported Pixel Formats</a></h3>
    4707. 

  4707. 

  4708. <p>x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
    4709. 

  4709. x264&rsquo;s configure time. FFmpeg only supports one bit depth in one particular
    4710. 

  4710. build. In other words, it is not possible to build one FFmpeg with multiple
    4711. 

  4711. versions of x264 with different bit depths.
    4712. 

  4712. </p>
    4713. 

  4713. <a name="Options-23"></a>
    4714. 

  4714. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-23">9.10.2 Options</a></h3>
    4715. 

  4715. 

  4716. <p>The following options are supported by the libx264 wrapper. The
    4717. 

  4717. <code>x264</code>-equivalent options or values are listed in parentheses
    4718. 

  4718. for easy migration.
    4719. 

  4719. </p>
    4720. 

  4720. <p>To reduce the duplication of documentation, only the private options
    4721. 

  4721. and some others requiring special attention are documented here. For
    4722. 

  4722. the documentation of the undocumented generic options, see
    4723. 

  4723. <a href="#codec_002doptions">the Codec Options chapter</a>.
    4724. 

  4724. </p>
    4725. 

  4725. <p>To get a more accurate and extensive documentation of the libx264
    4726. 

  4726. options, invoke the command <code>x264 --fullhelp</code> or consult
    4727. 

  4727. the libx264 documentation.
    4728. 

  4728. </p>
    4729. 

  4729. <dl compact="compact">
    4730. 

  4730. <dt>&lsquo;<samp>b (<em>bitrate</em>)</samp>&rsquo;</dt>
    4731. 

  4731. <dd><p>Set bitrate in bits/s. Note that FFmpeg&rsquo;s &lsquo;<samp>b</samp>&rsquo; option is
    4732. 

  4732. expressed in bits/s, while <code>x264</code>&rsquo;s &lsquo;<samp>bitrate</samp>&rsquo; is in
    4733. 

  4733. kilobits/s.
    4734. 

  4734. </p>
    4735. 

  4735. </dd>
    4736. 

  4736. <dt>&lsquo;<samp>bf (<em>bframes</em>)</samp>&rsquo;</dt>
    4737. 

  4737. <dt>&lsquo;<samp>g (<em>keyint</em>)</samp>&rsquo;</dt>
    4738. 

  4738. <dt>&lsquo;<samp>qmin (<em>qpmin</em>)</samp>&rsquo;</dt>
    4739. 

  4739. <dd><p>Minimum quantizer scale.
    4740. 

  4740. </p>
    4741. 

  4741. </dd>
    4742. 

  4742. <dt>&lsquo;<samp>qmax (<em>qpmax</em>)</samp>&rsquo;</dt>
    4743. 

  4743. <dd><p>Maximum quantizer scale.
    4744. 

  4744. </p>
    4745. 

  4745. </dd>
    4746. 

  4746. <dt>&lsquo;<samp>qdiff (<em>qpstep</em>)</samp>&rsquo;</dt>
    4747. 

  4747. <dd><p>Maximum difference between quantizer scales.
    4748. 

  4748. </p>
    4749. 

  4749. </dd>
    4750. 

  4750. <dt>&lsquo;<samp>qblur (<em>qblur</em>)</samp>&rsquo;</dt>
    4751. 

  4751. <dd><p>Quantizer curve blur
    4752. 

  4752. </p>
    4753. 

  4753. </dd>
    4754. 

  4754. <dt>&lsquo;<samp>qcomp (<em>qcomp</em>)</samp>&rsquo;</dt>
    4755. 

  4755. <dd><p>Quantizer curve compression factor
    4756. 

  4756. </p>
    4757. 

  4757. </dd>
    4758. 

  4758. <dt>&lsquo;<samp>refs (<em>ref</em>)</samp>&rsquo;</dt>
    4759. 

  4759. <dd><p>Number of reference frames each P-frame can use. The range is from <var>0-16</var>.
    4760. 

  4760. </p>
    4761. 

  4761. </dd>
    4762. 

  4762. <dt>&lsquo;<samp>sc_threshold (<em>scenecut</em>)</samp>&rsquo;</dt>
    4763. 

  4763. <dd><p>Sets the threshold for the scene change detection.
    4764. 

  4764. </p>
    4765. 

  4765. </dd>
    4766. 

  4766. <dt>&lsquo;<samp>trellis (<em>trellis</em>)</samp>&rsquo;</dt>
    4767. 

  4767. <dd><p>Performs Trellis quantization to increase efficiency. Enabled by default.
    4768. 

  4768. </p>
    4769. 

  4769. </dd>
    4770. 

  4770. <dt>&lsquo;<samp>nr  (<em>nr</em>)</samp>&rsquo;</dt>
    4771. 

  4771. <dt>&lsquo;<samp>me_range (<em>merange</em>)</samp>&rsquo;</dt>
    4772. 

  4772. <dd><p>Maximum range of the motion search in pixels.
    4773. 

  4773. </p>
    4774. 

  4774. </dd>
    4775. 

  4775. <dt>&lsquo;<samp>me_method (<em>me</em>)</samp>&rsquo;</dt>
    4776. 

  4776. <dd><p>Set motion estimation method. Possible values in the decreasing order
    4777. 

  4777. of speed:
    4778. 

  4778. </p>
    4779. 

  4779. <dl compact="compact">
    4780. 

  4780. <dt>&lsquo;<samp>dia (<em>dia</em>)</samp>&rsquo;</dt>
    4781. 

  4781. <dt>&lsquo;<samp>epzs (<em>dia</em>)</samp>&rsquo;</dt>
    4782. 

  4782. <dd><p>Diamond search with radius 1 (fastest). &lsquo;<samp>epzs</samp>&rsquo; is an alias for
    4783. 

  4783. &lsquo;<samp>dia</samp>&rsquo;.
    4784. 

  4784. </p></dd>
    4785. 

  4785. <dt>&lsquo;<samp>hex (<em>hex</em>)</samp>&rsquo;</dt>
    4786. 

  4786. <dd><p>Hexagonal search with radius 2.
    4787. 

  4787. </p></dd>
    4788. 

  4788. <dt>&lsquo;<samp>umh (<em>umh</em>)</samp>&rsquo;</dt>
    4789. 

  4789. <dd><p>Uneven multi-hexagon search.
    4790. 

  4790. </p></dd>
    4791. 

  4791. <dt>&lsquo;<samp>esa (<em>esa</em>)</samp>&rsquo;</dt>
    4792. 

  4792. <dd><p>Exhaustive search.
    4793. 

  4793. </p></dd>
    4794. 

  4794. <dt>&lsquo;<samp>tesa (<em>tesa</em>)</samp>&rsquo;</dt>
    4795. 

  4795. <dd><p>Hadamard exhaustive search (slowest).
    4796. 

  4796. </p></dd>
    4797. 

  4797. </dl>
    4798. 

  4798. 

  4799. </dd>
    4800. 

  4800. <dt>&lsquo;<samp>forced-idr</samp>&rsquo;</dt>
    4801. 

  4801. <dd><p>Normally, when forcing a I-frame type, the encoder can select any type
    4802. 

  4802. of I-frame. This option forces it to choose an IDR-frame.
    4803. 

  4803. </p>
    4804. 

  4804. </dd>
    4805. 

  4805. <dt>&lsquo;<samp>subq (<em>subme</em>)</samp>&rsquo;</dt>
    4806. 

  4806. <dd><p>Sub-pixel motion estimation method.
    4807. 

  4807. </p>
    4808. 

  4808. </dd>
    4809. 

  4809. <dt>&lsquo;<samp>b_strategy (<em>b-adapt</em>)</samp>&rsquo;</dt>
    4810. 

  4810. <dd><p>Adaptive B-frame placement decision algorithm. Use only on first-pass.
    4811. 

  4811. </p>
    4812. 

  4812. </dd>
    4813. 

  4813. <dt>&lsquo;<samp>keyint_min (<em>min-keyint</em>)</samp>&rsquo;</dt>
    4814. 

  4814. <dd><p>Minimum GOP size.
    4815. 

  4815. </p>
    4816. 

  4816. </dd>
    4817. 

  4817. <dt>&lsquo;<samp>coder</samp>&rsquo;</dt>
    4818. 

  4818. <dd><p>Set entropy encoder. Possible values:
    4819. 

  4819. </p>
    4820. 

  4820. <dl compact="compact">
    4821. 

  4821. <dt>&lsquo;<samp>ac</samp>&rsquo;</dt>
    4822. 

  4822. <dd><p>Enable CABAC.
    4823. 

  4823. </p>
    4824. 

  4824. </dd>
    4825. 

  4825. <dt>&lsquo;<samp>vlc</samp>&rsquo;</dt>
    4826. 

  4826. <dd><p>Enable CAVLC and disable CABAC. It generates the same effect as
    4827. 

  4827. <code>x264</code>&rsquo;s &lsquo;<samp>--no-cabac</samp>&rsquo; option.
    4828. 

  4828. </p></dd>
    4829. 

  4829. </dl>
    4830. 

  4830. 

  4831. </dd>
    4832. 

  4832. <dt>&lsquo;<samp>cmp</samp>&rsquo;</dt>
    4833. 

  4833. <dd><p>Set full pixel motion estimation comparison algorithm. Possible values:
    4834. 

  4834. </p>
    4835. 

  4835. <dl compact="compact">
    4836. 

  4836. <dt>&lsquo;<samp>chroma</samp>&rsquo;</dt>
    4837. 

  4837. <dd><p>Enable chroma in motion estimation.
    4838. 

  4838. </p>
    4839. 

  4839. </dd>
    4840. 

  4840. <dt>&lsquo;<samp>sad</samp>&rsquo;</dt>
    4841. 

  4841. <dd><p>Ignore chroma in motion estimation. It generates the same effect as
    4842. 

  4842. <code>x264</code>&rsquo;s &lsquo;<samp>--no-chroma-me</samp>&rsquo; option.
    4843. 

  4843. </p></dd>
    4844. 

  4844. </dl>
    4845. 

  4845. 

  4846. </dd>
    4847. 

  4847. <dt>&lsquo;<samp>threads (<em>threads</em>)</samp>&rsquo;</dt>
    4848. 

  4848. <dd><p>Number of encoding threads.
    4849. 

  4849. </p>
    4850. 

  4850. </dd>
    4851. 

  4851. <dt>&lsquo;<samp>thread_type</samp>&rsquo;</dt>
    4852. 

  4852. <dd><p>Set multithreading technique. Possible values:
    4853. 

  4853. </p>
    4854. 

  4854. <dl compact="compact">
    4855. 

  4855. <dt>&lsquo;<samp>slice</samp>&rsquo;</dt>
    4856. 

  4856. <dd><p>Slice-based multithreading. It generates the same effect as
    4857. 

  4857. <code>x264</code>&rsquo;s &lsquo;<samp>--sliced-threads</samp>&rsquo; option.
    4858. 

  4858. </p></dd>
    4859. 

  4859. <dt>&lsquo;<samp>frame</samp>&rsquo;</dt>
    4860. 

  4860. <dd><p>Frame-based multithreading.
    4861. 

  4861. </p></dd>
    4862. 

  4862. </dl>
    4863. 

  4863. 

  4864. </dd>
    4865. 

  4865. <dt>&lsquo;<samp>flags</samp>&rsquo;</dt>
    4866. 

  4866. <dd><p>Set encoding flags. It can be used to disable closed GOP and enable
    4867. 

  4867. open GOP by setting it to <code>-cgop</code>. The result is similar to
    4868. 

  4868. the behavior of <code>x264</code>&rsquo;s &lsquo;<samp>--open-gop</samp>&rsquo; option.
    4869. 

  4869. </p>
    4870. 

  4870. </dd>
    4871. 

  4871. <dt>&lsquo;<samp>rc_init_occupancy (<em>vbv-init</em>)</samp>&rsquo;</dt>
    4872. 

  4872. <dt>&lsquo;<samp>preset (<em>preset</em>)</samp>&rsquo;</dt>
    4873. 

  4873. <dd><p>Set the encoding preset.
    4874. 

  4874. </p>
    4875. 

  4875. </dd>
    4876. 

  4876. <dt>&lsquo;<samp>tune (<em>tune</em>)</samp>&rsquo;</dt>
    4877. 

  4877. <dd><p>Set tuning of the encoding params.
    4878. 

  4878. </p>
    4879. 

  4879. </dd>
    4880. 

  4880. <dt>&lsquo;<samp>profile (<em>profile</em>)</samp>&rsquo;</dt>
    4881. 

  4881. <dd><p>Set profile restrictions.
    4882. 

  4882. </p>
    4883. 

  4883. </dd>
    4884. 

  4884. <dt>&lsquo;<samp>fastfirstpass</samp>&rsquo;</dt>
    4885. 

  4885. <dd><p>Enable fast settings when encoding first pass, when set to 1. When set
    4886. 

  4886. to 0, it has the same effect of <code>x264</code>&rsquo;s
    4887. 

  4887. &lsquo;<samp>--slow-firstpass</samp>&rsquo; option.
    4888. 

  4888. </p>
    4889. 

  4889. </dd>
    4890. 

  4890. <dt>&lsquo;<samp>crf (<em>crf</em>)</samp>&rsquo;</dt>
    4891. 

  4891. <dd><p>Set the quality for constant quality mode.
    4892. 

  4892. </p>
    4893. 

  4893. </dd>
    4894. 

  4894. <dt>&lsquo;<samp>crf_max (<em>crf-max</em>)</samp>&rsquo;</dt>
    4895. 

  4895. <dd><p>In CRF mode, prevents VBV from lowering quality beyond this point.
    4896. 

  4896. </p>
    4897. 

  4897. </dd>
    4898. 

  4898. <dt>&lsquo;<samp>qp (<em>qp</em>)</samp>&rsquo;</dt>
    4899. 

  4899. <dd><p>Set constant quantization rate control method parameter.
    4900. 

  4900. </p>
    4901. 

  4901. </dd>
    4902. 

  4902. <dt>&lsquo;<samp>aq-mode (<em>aq-mode</em>)</samp>&rsquo;</dt>
    4903. 

  4903. <dd><p>Set AQ method. Possible values:
    4904. 

  4904. </p>
    4905. 

  4905. <dl compact="compact">
    4906. 

  4906. <dt>&lsquo;<samp>none (<em>0</em>)</samp>&rsquo;</dt>
    4907. 

  4907. <dd><p>Disabled.
    4908. 

  4908. </p>
    4909. 

  4909. </dd>
    4910. 

  4910. <dt>&lsquo;<samp>variance (<em>1</em>)</samp>&rsquo;</dt>
    4911. 

  4911. <dd><p>Variance AQ (complexity mask).
    4912. 

  4912. </p>
    4913. 

  4913. </dd>
    4914. 

  4914. <dt>&lsquo;<samp>autovariance (<em>2</em>)</samp>&rsquo;</dt>
    4915. 

  4915. <dd><p>Auto-variance AQ (experimental).
    4916. 

  4916. </p></dd>
    4917. 

  4917. </dl>
    4918. 

  4918. 

  4919. </dd>
    4920. 

  4920. <dt>&lsquo;<samp>aq-strength (<em>aq-strength</em>)</samp>&rsquo;</dt>
    4921. 

  4921. <dd><p>Set AQ strength, reduce blocking and blurring in flat and textured areas.
    4922. 

  4922. </p>
    4923. 

  4923. </dd>
    4924. 

  4924. <dt>&lsquo;<samp>psy</samp>&rsquo;</dt>
    4925. 

  4925. <dd><p>Use psychovisual optimizations when set to 1. When set to 0, it has the
    4926. 

  4926. same effect as <code>x264</code>&rsquo;s &lsquo;<samp>--no-psy</samp>&rsquo; option.
    4927. 

  4927. </p>
    4928. 

  4928. </dd>
    4929. 

  4929. <dt>&lsquo;<samp>psy-rd  (<em>psy-rd</em>)</samp>&rsquo;</dt>
    4930. 

  4930. <dd><p>Set strength of psychovisual optimization, in
    4931. 

  4931. <var>psy-rd</var>:<var>psy-trellis</var> format.
    4932. 

  4932. </p>
    4933. 

  4933. </dd>
    4934. 

  4934. <dt>&lsquo;<samp>rc-lookahead (<em>rc-lookahead</em>)</samp>&rsquo;</dt>
    4935. 

  4935. <dd><p>Set number of frames to look ahead for frametype and ratecontrol.
    4936. 

  4936. </p>
    4937. 

  4937. </dd>
    4938. 

  4938. <dt>&lsquo;<samp>weightb</samp>&rsquo;</dt>
    4939. 

  4939. <dd><p>Enable weighted prediction for B-frames when set to 1. When set to 0,
    4940. 

  4940. it has the same effect as <code>x264</code>&rsquo;s &lsquo;<samp>--no-weightb</samp>&rsquo; option.
    4941. 

  4941. </p>
    4942. 

  4942. </dd>
    4943. 

  4943. <dt>&lsquo;<samp>weightp (<em>weightp</em>)</samp>&rsquo;</dt>
    4944. 

  4944. <dd><p>Set weighted prediction method for P-frames. Possible values:
    4945. 

  4945. </p>
    4946. 

  4946. <dl compact="compact">
    4947. 

  4947. <dt>&lsquo;<samp>none (<em>0</em>)</samp>&rsquo;</dt>
    4948. 

  4948. <dd><p>Disabled
    4949. 

  4949. </p></dd>
    4950. 

  4950. <dt>&lsquo;<samp>simple (<em>1</em>)</samp>&rsquo;</dt>
    4951. 

  4951. <dd><p>Enable only weighted refs
    4952. 

  4952. </p></dd>
    4953. 

  4953. <dt>&lsquo;<samp>smart (<em>2</em>)</samp>&rsquo;</dt>
    4954. 

  4954. <dd><p>Enable both weighted refs and duplicates
    4955. 

  4955. </p></dd>
    4956. 

  4956. </dl>
    4957. 

  4957. 

  4958. </dd>
    4959. 

  4959. <dt>&lsquo;<samp>ssim (<em>ssim</em>)</samp>&rsquo;</dt>
    4960. 

  4960. <dd><p>Enable calculation and printing SSIM stats after the encoding.
    4961. 

  4961. </p>
    4962. 

  4962. </dd>
    4963. 

  4963. <dt>&lsquo;<samp>intra-refresh (<em>intra-refresh</em>)</samp>&rsquo;</dt>
    4964. 

  4964. <dd><p>Enable the use of Periodic Intra Refresh instead of IDR frames when set
    4965. 

  4965. to 1.
    4966. 

  4966. </p>
    4967. 

  4967. </dd>
    4968. 

  4968. <dt>&lsquo;<samp>avcintra-class (<em>class</em>)</samp>&rsquo;</dt>
    4969. 

  4969. <dd><p>Configure the encoder to generate AVC-Intra.
    4970. 

  4970. Valid values are 50,100 and 200
    4971. 

  4971. </p>
    4972. 

  4972. </dd>
    4973. 

  4973. <dt>&lsquo;<samp>bluray-compat (<em>bluray-compat</em>)</samp>&rsquo;</dt>
    4974. 

  4974. <dd><p>Configure the encoder to be compatible with the bluray standard.
    4975. 

  4975. It is a shorthand for setting &quot;bluray-compat=1 force-cfr=1&quot;.
    4976. 

  4976. </p>
    4977. 

  4977. </dd>
    4978. 

  4978. <dt>&lsquo;<samp>b-bias (<em>b-bias</em>)</samp>&rsquo;</dt>
    4979. 

  4979. <dd><p>Set the influence on how often B-frames are used.
    4980. 

  4980. </p>
    4981. 

  4981. </dd>
    4982. 

  4982. <dt>&lsquo;<samp>b-pyramid (<em>b-pyramid</em>)</samp>&rsquo;</dt>
    4983. 

  4983. <dd><p>Set method for keeping of some B-frames as references. Possible values:
    4984. 

  4984. </p>
    4985. 

  4985. <dl compact="compact">
    4986. 

  4986. <dt>&lsquo;<samp>none (<em>none</em>)</samp>&rsquo;</dt>
    4987. 

  4987. <dd><p>Disabled.
    4988. 

  4988. </p></dd>
    4989. 

  4989. <dt>&lsquo;<samp>strict (<em>strict</em>)</samp>&rsquo;</dt>
    4990. 

  4990. <dd><p>Strictly hierarchical pyramid.
    4991. 

  4991. </p></dd>
    4992. 

  4992. <dt>&lsquo;<samp>normal (<em>normal</em>)</samp>&rsquo;</dt>
    4993. 

  4993. <dd><p>Non-strict (not Blu-ray compatible).
    4994. 

  4994. </p></dd>
    4995. 

  4995. </dl>
    4996. 

  4996. 

  4997. </dd>
    4998. 

  4998. <dt>&lsquo;<samp>mixed-refs</samp>&rsquo;</dt>
    4999. 

  4999. <dd><p>Enable the use of one reference per partition, as opposed to one
    5000. 

  5000. reference per macroblock when set to 1. When set to 0, it has the
    5001. 

  5001. same effect as <code>x264</code>&rsquo;s &lsquo;<samp>--no-mixed-refs</samp>&rsquo; option.
    5002. 

  5002. </p>
    5003. 

  5003. </dd>
    5004. 

  5004. <dt>&lsquo;<samp>8x8dct</samp>&rsquo;</dt>
    5005. 

  5005. <dd><p>Enable adaptive spatial transform (high profile 8x8 transform)
    5006. 

  5006. when set to 1. When set to 0, it has the same effect as
    5007. 

  5007. <code>x264</code>&rsquo;s &lsquo;<samp>--no-8x8dct</samp>&rsquo; option.
    5008. 

  5008. </p>
    5009. 

  5009. </dd>
    5010. 

  5010. <dt>&lsquo;<samp>fast-pskip</samp>&rsquo;</dt>
    5011. 

  5011. <dd><p>Enable early SKIP detection on P-frames when set to 1. When set
    5012. 

  5012. to 0, it has the same effect as <code>x264</code>&rsquo;s
    5013. 

  5013. &lsquo;<samp>--no-fast-pskip</samp>&rsquo; option.
    5014. 

  5014. </p>
    5015. 

  5015. </dd>
    5016. 

  5016. <dt>&lsquo;<samp>aud (<em>aud</em>)</samp>&rsquo;</dt>
    5017. 

  5017. <dd><p>Enable use of access unit delimiters when set to 1.
    5018. 

  5018. </p>
    5019. 

  5019. </dd>
    5020. 

  5020. <dt>&lsquo;<samp>mbtree</samp>&rsquo;</dt>
    5021. 

  5021. <dd><p>Enable use macroblock tree ratecontrol when set to 1. When set
    5022. 

  5022. to 0, it has the same effect as <code>x264</code>&rsquo;s
    5023. 

  5023. &lsquo;<samp>--no-mbtree</samp>&rsquo; option.
    5024. 

  5024. </p>
    5025. 

  5025. </dd>
    5026. 

  5026. <dt>&lsquo;<samp>deblock (<em>deblock</em>)</samp>&rsquo;</dt>
    5027. 

  5027. <dd><p>Set loop filter parameters, in <var>alpha</var>:<var>beta</var> form.
    5028. 

  5028. </p>
    5029. 

  5029. </dd>
    5030. 

  5030. <dt>&lsquo;<samp>cplxblur (<em>cplxblur</em>)</samp>&rsquo;</dt>
    5031. 

  5031. <dd><p>Set fluctuations reduction in QP (before curve compression).
    5032. 

  5032. </p>
    5033. 

  5033. </dd>
    5034. 

  5034. <dt>&lsquo;<samp>partitions (<em>partitions</em>)</samp>&rsquo;</dt>
    5035. 

  5035. <dd><p>Set partitions to consider as a comma-separated list of. Possible
    5036. 

  5036. values in the list:
    5037. 

  5037. </p>
    5038. 

  5038. <dl compact="compact">
    5039. 

  5039. <dt>&lsquo;<samp>p8x8</samp>&rsquo;</dt>
    5040. 

  5040. <dd><p>8x8 P-frame partition.
    5041. 

  5041. </p></dd>
    5042. 

  5042. <dt>&lsquo;<samp>p4x4</samp>&rsquo;</dt>
    5043. 

  5043. <dd><p>4x4 P-frame partition.
    5044. 

  5044. </p></dd>
    5045. 

  5045. <dt>&lsquo;<samp>b8x8</samp>&rsquo;</dt>
    5046. 

  5046. <dd><p>4x4 B-frame partition.
    5047. 

  5047. </p></dd>
    5048. 

  5048. <dt>&lsquo;<samp>i8x8</samp>&rsquo;</dt>
    5049. 

  5049. <dd><p>8x8 I-frame partition.
    5050. 

  5050. </p></dd>
    5051. 

  5051. <dt>&lsquo;<samp>i4x4</samp>&rsquo;</dt>
    5052. 

  5052. <dd><p>4x4 I-frame partition.
    5053. 

  5053. (Enabling &lsquo;<samp>p4x4</samp>&rsquo; requires &lsquo;<samp>p8x8</samp>&rsquo; to be enabled. Enabling
    5054. 

  5054. &lsquo;<samp>i8x8</samp>&rsquo; requires adaptive spatial transform (&lsquo;<samp>8x8dct</samp>&rsquo;
    5055. 

  5055. option) to be enabled.)
    5056. 

  5056. </p></dd>
    5057. 

  5057. <dt>&lsquo;<samp>none (<em>none</em>)</samp>&rsquo;</dt>
    5058. 

  5058. <dd><p>Do not consider any partitions.
    5059. 

  5059. </p></dd>
    5060. 

  5060. <dt>&lsquo;<samp>all (<em>all</em>)</samp>&rsquo;</dt>
    5061. 

  5061. <dd><p>Consider every partition.
    5062. 

  5062. </p></dd>
    5063. 

  5063. </dl>
    5064. 

  5064. 

  5065. </dd>
    5066. 

  5066. <dt>&lsquo;<samp>direct-pred (<em>direct</em>)</samp>&rsquo;</dt>
    5067. 

  5067. <dd><p>Set direct MV prediction mode. Possible values:
    5068. 

  5068. </p>
    5069. 

  5069. <dl compact="compact">
    5070. 

  5070. <dt>&lsquo;<samp>none (<em>none</em>)</samp>&rsquo;</dt>
    5071. 

  5071. <dd><p>Disable MV prediction.
    5072. 

  5072. </p></dd>
    5073. 

  5073. <dt>&lsquo;<samp>spatial (<em>spatial</em>)</samp>&rsquo;</dt>
    5074. 

  5074. <dd><p>Enable spatial predicting.
    5075. 

  5075. </p></dd>
    5076. 

  5076. <dt>&lsquo;<samp>temporal (<em>temporal</em>)</samp>&rsquo;</dt>
    5077. 

  5077. <dd><p>Enable temporal predicting.
    5078. 

  5078. </p></dd>
    5079. 

  5079. <dt>&lsquo;<samp>auto (<em>auto</em>)</samp>&rsquo;</dt>
    5080. 

  5080. <dd><p>Automatically decided.
    5081. 

  5081. </p></dd>
    5082. 

  5082. </dl>
    5083. 

  5083. 

  5084. </dd>
    5085. 

  5085. <dt>&lsquo;<samp>slice-max-size (<em>slice-max-size</em>)</samp>&rsquo;</dt>
    5086. 

  5086. <dd><p>Set the limit of the size of each slice in bytes. If not specified
    5087. 

  5087. but RTP payload size (&lsquo;<samp>ps</samp>&rsquo;) is specified, that is used.
    5088. 

  5088. </p>
    5089. 

  5089. </dd>
    5090. 

  5090. <dt>&lsquo;<samp>stats (<em>stats</em>)</samp>&rsquo;</dt>
    5091. 

  5091. <dd><p>Set the file name for multi-pass stats.
    5092. 

  5092. </p>
    5093. 

  5093. </dd>
    5094. 

  5094. <dt>&lsquo;<samp>nal-hrd (<em>nal-hrd</em>)</samp>&rsquo;</dt>
    5095. 

  5095. <dd><p>Set signal HRD information (requires &lsquo;<samp>vbv-bufsize</samp>&rsquo; to be set).
    5096. 

  5096. Possible values:
    5097. 

  5097. </p>
    5098. 

  5098. <dl compact="compact">
    5099. 

  5099. <dt>&lsquo;<samp>none (<em>none</em>)</samp>&rsquo;</dt>
    5100. 

  5100. <dd><p>Disable HRD information signaling.
    5101. 

  5101. </p></dd>
    5102. 

  5102. <dt>&lsquo;<samp>vbr (<em>vbr</em>)</samp>&rsquo;</dt>
    5103. 

  5103. <dd><p>Variable bit rate.
    5104. 

  5104. </p></dd>
    5105. 

  5105. <dt>&lsquo;<samp>cbr (<em>cbr</em>)</samp>&rsquo;</dt>
    5106. 

  5106. <dd><p>Constant bit rate (not allowed in MP4 container).
    5107. 

  5107. </p></dd>
    5108. 

  5108. </dl>
    5109. 

  5109. 

  5110. </dd>
    5111. 

  5111. <dt>&lsquo;<samp>x264opts (N.A.)</samp>&rsquo;</dt>
    5112. 

  5112. <dd><p>Set any x264 option, see <code>x264 --fullhelp</code> for a list.
    5113. 

  5113. </p>
    5114. 

  5114. <p>Argument is a list of <var>key</var>=<var>value</var> couples separated by
    5115. 

  5115. &quot;:&quot;. In <var>filter</var> and <var>psy-rd</var> options that use &quot;:&quot; as a separator
    5116. 

  5116. themselves, use &quot;,&quot; instead. They accept it as well since long ago but this
    5117. 

  5117. is kept undocumented for some reason.
    5118. 

  5118. </p>
    5119. 

  5119. <p>For example to specify libx264 encoding options with <code>ffmpeg</code>:
    5120. 

  5120. </p><div class="example">
    5121. 

  5121. <pre class="example">ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
    5122. 

  5122. </pre></div>
    5123. 

  5123. 

  5124. </dd>
    5125. 

  5125. <dt>&lsquo;<samp>a53cc <var>boolean</var></samp>&rsquo;</dt>
    5126. 

  5126. <dd><p>Import closed captions (which must be ATSC compatible format) into output.
    5127. 

  5127. Only the mpeg2 and h264 decoders provide these. Default is 1 (on).
    5128. 

  5128. </p>
    5129. 

  5129. </dd>
    5130. 

  5130. <dt>&lsquo;<samp>x264-params (N.A.)</samp>&rsquo;</dt>
    5131. 

  5131. <dd><p>Override the x264 configuration using a :-separated list of key=value
    5132. 

  5132. parameters.
    5133. 

  5133. </p>
    5134. 

  5134. <p>This option is functionally the same as the &lsquo;<samp>x264opts</samp>&rsquo;, but is
    5135. 

  5135. duplicated for compatibility with the Libav fork.
    5136. 

  5136. </p>
    5137. 

  5137. <p>For example to specify libx264 encoding options with <code>ffmpeg</code>:
    5138. 

  5138. </p><div class="example">
    5139. 

  5139. <pre class="example">ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
    5140. 

  5140. cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
    5141. 

  5141. no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
    5142. 

  5142. </pre></div>
    5143. 

  5143. </dd>
    5144. 

  5144. </dl>
    5145. 

  5145. 

  5146. <p>Encoding ffpresets for common usages are provided so they can be used with the
    5147. 

  5147. general presets system (e.g. passing the &lsquo;<samp>pre</samp>&rsquo; option).
    5148. 

  5148. </p>
    5149. 

  5149. <a name="libx265"></a>
    5150. 

  5150. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libx265">9.11 libx265</a></h2>
    5151. 

  5151. 

  5152. <p>x265 H.265/HEVC encoder wrapper.
    5153. 

  5153. </p>
    5154. 

  5154. <p>This encoder requires the presence of the libx265 headers and library
    5155. 

  5155. during configuration. You need to explicitly configure the build with
    5156. 

  5156. &lsquo;<samp>--enable-libx265</samp>&rsquo;.
    5157. 

  5157. </p>
    5158. 

  5158. <a name="Options-2"></a>
    5159. 

  5159. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-2">9.11.1 Options</a></h3>
    5160. 

  5160. 

  5161. <dl compact="compact">
    5162. 

  5162. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    5163. 

  5163. <dd><p>Sets target video bitrate.
    5164. 

  5164. </p>
    5165. 

  5165. </dd>
    5166. 

  5166. <dt>&lsquo;<samp>bf</samp>&rsquo;</dt>
    5167. 

  5167. <dt>&lsquo;<samp>g</samp>&rsquo;</dt>
    5168. 

  5168. <dd><p>Set the GOP size.
    5169. 

  5169. </p>
    5170. 

  5170. </dd>
    5171. 

  5171. <dt>&lsquo;<samp>keyint_min</samp>&rsquo;</dt>
    5172. 

  5172. <dd><p>Minimum GOP size.
    5173. 

  5173. </p>
    5174. 

  5174. </dd>
    5175. 

  5175. <dt>&lsquo;<samp>refs</samp>&rsquo;</dt>
    5176. 

  5176. <dd><p>Number of reference frames each P-frame can use. The range is from <var>1-16</var>.
    5177. 

  5177. </p>
    5178. 

  5178. </dd>
    5179. 

  5179. <dt>&lsquo;<samp>preset</samp>&rsquo;</dt>
    5180. 

  5180. <dd><p>Set the x265 preset.
    5181. 

  5181. </p>
    5182. 

  5182. </dd>
    5183. 

  5183. <dt>&lsquo;<samp>tune</samp>&rsquo;</dt>
    5184. 

  5184. <dd><p>Set the x265 tune parameter.
    5185. 

  5185. </p>
    5186. 

  5186. </dd>
    5187. 

  5187. <dt>&lsquo;<samp>profile</samp>&rsquo;</dt>
    5188. 

  5188. <dd><p>Set profile restrictions.
    5189. 

  5189. </p>
    5190. 

  5190. </dd>
    5191. 

  5191. <dt>&lsquo;<samp>crf</samp>&rsquo;</dt>
    5192. 

  5192. <dd><p>Set the quality for constant quality mode.
    5193. 

  5193. </p>
    5194. 

  5194. </dd>
    5195. 

  5195. <dt>&lsquo;<samp>qp</samp>&rsquo;</dt>
    5196. 

  5196. <dd><p>Set constant quantization rate control method parameter.
    5197. 

  5197. </p>
    5198. 

  5198. </dd>
    5199. 

  5199. <dt>&lsquo;<samp>qmin</samp>&rsquo;</dt>
    5200. 

  5200. <dd><p>Minimum quantizer scale.
    5201. 

  5201. </p>
    5202. 

  5202. </dd>
    5203. 

  5203. <dt>&lsquo;<samp>qmax</samp>&rsquo;</dt>
    5204. 

  5204. <dd><p>Maximum quantizer scale.
    5205. 

  5205. </p>
    5206. 

  5206. </dd>
    5207. 

  5207. <dt>&lsquo;<samp>qdiff</samp>&rsquo;</dt>
    5208. 

  5208. <dd><p>Maximum difference between quantizer scales.
    5209. 

  5209. </p>
    5210. 

  5210. </dd>
    5211. 

  5211. <dt>&lsquo;<samp>qblur</samp>&rsquo;</dt>
    5212. 

  5212. <dd><p>Quantizer curve blur
    5213. 

  5213. </p>
    5214. 

  5214. </dd>
    5215. 

  5215. <dt>&lsquo;<samp>qcomp</samp>&rsquo;</dt>
    5216. 

  5216. <dd><p>Quantizer curve compression factor
    5217. 

  5217. </p>
    5218. 

  5218. </dd>
    5219. 

  5219. <dt>&lsquo;<samp>i_qfactor</samp>&rsquo;</dt>
    5220. 

  5220. <dt>&lsquo;<samp>b_qfactor</samp>&rsquo;</dt>
    5221. 

  5221. <dt>&lsquo;<samp>forced-idr</samp>&rsquo;</dt>
    5222. 

  5222. <dd><p>Normally, when forcing a I-frame type, the encoder can select any type
    5223. 

  5223. of I-frame. This option forces it to choose an IDR-frame.
    5224. 

  5224. </p>
    5225. 

  5225. </dd>
    5226. 

  5226. <dt>&lsquo;<samp>x265-params</samp>&rsquo;</dt>
    5227. 

  5227. <dd><p>Set x265 options using a list of <var>key</var>=<var>value</var> couples separated
    5228. 

  5228. by &quot;:&quot;. See <code>x265 --help</code> for a list of options.
    5229. 

  5229. </p>
    5230. 

  5230. <p>For example to specify libx265 encoding options with &lsquo;<samp>-x265-params</samp>&rsquo;:
    5231. 

  5231. </p>
    5232. 

  5232. <div class="example">
    5233. 

  5233. <pre class="example">ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
    5234. 

  5234. </pre></div>
    5235. 

  5235. </dd>
    5236. 

  5236. </dl>
    5237. 

  5237. 

  5238. <a name="libxavs2"></a>
    5239. 

  5239. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libxavs2">9.12 libxavs2</a></h2>
    5240. 

  5240. 

  5241. <p>xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.
    5242. 

  5242. </p>
    5243. 

  5243. <p>This encoder requires the presence of the libxavs2 headers and library
    5244. 

  5244. during configuration. You need to explicitly configure the build with
    5245. 

  5245. &lsquo;<samp>--enable-libxavs2</samp>&rsquo;.
    5246. 

  5246. </p>
    5247. 

  5247. <p>The following standard libavcodec options are used:
    5248. 

  5248. </p><ul>
    5249. 

  5249. <li>
    5250. 

  5250. &lsquo;<samp>b</samp>&rsquo; / &lsquo;<samp>bit_rate</samp>&rsquo;
    5251. 

  5251. </li><li>
    5252. 

  5252. &lsquo;<samp>g</samp>&rsquo; / &lsquo;<samp>gop_size</samp>&rsquo;
    5253. 

  5253. </li><li>
    5254. 

  5254. &lsquo;<samp>bf</samp>&rsquo; / &lsquo;<samp>max_b_frames</samp>&rsquo;
    5255. 

  5255. </li></ul>
    5256. 

  5256. 

  5257. <p>The encoder also has its own specific options:
    5258. 

  5258. </p><a name="Options-27"></a>
    5259. 

  5259. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-27">9.12.1 Options</a></h3>
    5260. 

  5260. 

  5261. <dl compact="compact">
    5262. 

  5262. <dt>&lsquo;<samp>lcu_row_threads</samp>&rsquo;</dt>
    5263. 

  5263. <dd><p>Set the number of parallel threads for rows from 1 to 8 (default 5).
    5264. 

  5264. </p>
    5265. 

  5265. </dd>
    5266. 

  5266. <dt>&lsquo;<samp>initial_qp</samp>&rsquo;</dt>
    5267. 

  5267. <dd><p>Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
    5268. 

  5268. used to set the initial qp for the first frame.
    5269. 

  5269. </p>
    5270. 

  5270. </dd>
    5271. 

  5271. <dt>&lsquo;<samp>qp</samp>&rsquo;</dt>
    5272. 

  5272. <dd><p>Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
    5273. 

  5273. used to set the qp value under constant-QP mode.
    5274. 

  5274. </p>
    5275. 

  5275. </dd>
    5276. 

  5276. <dt>&lsquo;<samp>max_qp</samp>&rsquo;</dt>
    5277. 

  5277. <dd><p>Set the max qp for rate control from 1 to 63 (default 55).
    5278. 

  5278. </p>
    5279. 

  5279. </dd>
    5280. 

  5280. <dt>&lsquo;<samp>min_qp</samp>&rsquo;</dt>
    5281. 

  5281. <dd><p>Set the min qp for rate control from 1 to 63 (default 20).
    5282. 

  5282. </p>
    5283. 

  5283. </dd>
    5284. 

  5284. <dt>&lsquo;<samp>speed_level</samp>&rsquo;</dt>
    5285. 

  5285. <dd><p>Set the Speed level from 0 to 9 (default 0). Higher is better but slower.
    5286. 

  5286. </p>
    5287. 

  5287. </dd>
    5288. 

  5288. <dt>&lsquo;<samp>log_level</samp>&rsquo;</dt>
    5289. 

  5289. <dd><p>Set the log level from -1 to 3 (default 0). -1: none, 0: error,
    5290. 

  5290. 1: warning, 2: info, 3: debug.
    5291. 

  5291. </p>
    5292. 

  5292. </dd>
    5293. 

  5293. <dt>&lsquo;<samp>xavs2-params</samp>&rsquo;</dt>
    5294. 

  5294. <dd><p>Set xavs2 options using a list of <var>key</var>=<var>value</var> couples separated
    5295. 

  5295. by &quot;:&quot;.
    5296. 

  5296. </p>
    5297. 

  5297. <p>For example to specify libxavs2 encoding options with &lsquo;<samp>-xavs2-params</samp>&rsquo;:
    5298. 

  5298. </p>
    5299. 

  5299. <div class="example">
    5300. 

  5300. <pre class="example">ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2
    5301. 

  5301. </pre></div>
    5302. 

  5302. </dd>
    5303. 

  5303. </dl>
    5304. 

  5304. 

  5305. <a name="libxvid"></a>
    5306. 

  5306. <h2 class="section"><a href="ffmpeg-codecs.html#toc-libxvid">9.13 libxvid</a></h2>
    5307. 

  5307. 

  5308. <p>Xvid MPEG-4 Part 2 encoder wrapper.
    5309. 

  5309. </p>
    5310. 

  5310. <p>This encoder requires the presence of the libxvidcore headers and library
    5311. 

  5311. during configuration. You need to explicitly configure the build with
    5312. 

  5312. <code>--enable-libxvid --enable-gpl</code>.
    5313. 

  5313. </p>
    5314. 

  5314. <p>The native <code>mpeg4</code> encoder supports the MPEG-4 Part 2 format, so
    5315. 

  5315. users can encode to this format without this library.
    5316. 

  5316. </p>
    5317. 

  5317. <a name="Options-25"></a>
    5318. 

  5318. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-25">9.13.1 Options</a></h3>
    5319. 

  5319. 

  5320. <p>The following options are supported by the libxvid wrapper. Some of
    5321. 

  5321. the following options are listed but are not documented, and
    5322. 

  5322. correspond to shared codec options. See <a href="#codec_002doptions">the Codec Options chapter</a> for their documentation. The other shared options
    5323. 

  5323. which are not listed have no effect for the libxvid encoder.
    5324. 

  5324. </p>
    5325. 

  5325. <dl compact="compact">
    5326. 

  5326. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    5327. 

  5327. <dt>&lsquo;<samp>g</samp>&rsquo;</dt>
    5328. 

  5328. <dt>&lsquo;<samp>qmin</samp>&rsquo;</dt>
    5329. 

  5329. <dt>&lsquo;<samp>qmax</samp>&rsquo;</dt>
    5330. 

  5330. <dt>&lsquo;<samp>mpeg_quant</samp>&rsquo;</dt>
    5331. 

  5331. <dt>&lsquo;<samp>threads</samp>&rsquo;</dt>
    5332. 

  5332. <dt>&lsquo;<samp>bf</samp>&rsquo;</dt>
    5333. 

  5333. <dt>&lsquo;<samp>b_qfactor</samp>&rsquo;</dt>
    5334. 

  5334. <dt>&lsquo;<samp>b_qoffset</samp>&rsquo;</dt>
    5335. 

  5335. <dt>&lsquo;<samp>flags</samp>&rsquo;</dt>
    5336. 

  5336. <dd><p>Set specific encoding flags. Possible values:
    5337. 

  5337. </p>
    5338. 

  5338. <dl compact="compact">
    5339. 

  5339. <dt>&lsquo;<samp>mv4</samp>&rsquo;</dt>
    5340. 

  5340. <dd><p>Use four motion vector by macroblock.
    5341. 

  5341. </p>
    5342. 

  5342. </dd>
    5343. 

  5343. <dt>&lsquo;<samp>aic</samp>&rsquo;</dt>
    5344. 

  5344. <dd><p>Enable high quality AC prediction.
    5345. 

  5345. </p>
    5346. 

  5346. </dd>
    5347. 

  5347. <dt>&lsquo;<samp>gray</samp>&rsquo;</dt>
    5348. 

  5348. <dd><p>Only encode grayscale.
    5349. 

  5349. </p>
    5350. 

  5350. </dd>
    5351. 

  5351. <dt>&lsquo;<samp>gmc</samp>&rsquo;</dt>
    5352. 

  5352. <dd><p>Enable the use of global motion compensation (GMC).
    5353. 

  5353. </p>
    5354. 

  5354. </dd>
    5355. 

  5355. <dt>&lsquo;<samp>qpel</samp>&rsquo;</dt>
    5356. 

  5356. <dd><p>Enable quarter-pixel motion compensation.
    5357. 

  5357. </p>
    5358. 

  5358. </dd>
    5359. 

  5359. <dt>&lsquo;<samp>cgop</samp>&rsquo;</dt>
    5360. 

  5360. <dd><p>Enable closed GOP.
    5361. 

  5361. </p>
    5362. 

  5362. </dd>
    5363. 

  5363. <dt>&lsquo;<samp>global_header</samp>&rsquo;</dt>
    5364. 

  5364. <dd><p>Place global headers in extradata instead of every keyframe.
    5365. 

  5365. </p>
    5366. 

  5366. </dd>
    5367. 

  5367. </dl>
    5368. 

  5368. 

  5369. </dd>
    5370. 

  5370. <dt>&lsquo;<samp>trellis</samp>&rsquo;</dt>
    5371. 

  5371. <dt>&lsquo;<samp>me_method</samp>&rsquo;</dt>
    5372. 

  5372. <dd><p>Set motion estimation method. Possible values in decreasing order of
    5373. 

  5373. speed and increasing order of quality:
    5374. 

  5374. </p>
    5375. 

  5375. <dl compact="compact">
    5376. 

  5376. <dt>&lsquo;<samp>zero</samp>&rsquo;</dt>
    5377. 

  5377. <dd><p>Use no motion estimation (default).
    5378. 

  5378. </p>
    5379. 

  5379. </dd>
    5380. 

  5380. <dt>&lsquo;<samp>phods</samp>&rsquo;</dt>
    5381. 

  5381. <dt>&lsquo;<samp>x1</samp>&rsquo;</dt>
    5382. 

  5382. <dt>&lsquo;<samp>log</samp>&rsquo;</dt>
    5383. 

  5383. <dd><p>Enable advanced diamond zonal search for 16x16 blocks and half-pixel
    5384. 

  5384. refinement for 16x16 blocks. &lsquo;<samp>x1</samp>&rsquo; and &lsquo;<samp>log</samp>&rsquo; are aliases for
    5385. 

  5385. &lsquo;<samp>phods</samp>&rsquo;.
    5386. 

  5386. </p>
    5387. 

  5387. </dd>
    5388. 

  5388. <dt>&lsquo;<samp>epzs</samp>&rsquo;</dt>
    5389. 

  5389. <dd><p>Enable all of the things described above, plus advanced diamond zonal
    5390. 

  5390. search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
    5391. 

  5391. estimation on chroma planes.
    5392. 

  5392. </p>
    5393. 

  5393. </dd>
    5394. 

  5394. <dt>&lsquo;<samp>full</samp>&rsquo;</dt>
    5395. 

  5395. <dd><p>Enable all of the things described above, plus extended 16x16 and 8x8
    5396. 

  5396. blocks search.
    5397. 

  5397. </p></dd>
    5398. 

  5398. </dl>
    5399. 

  5399. 

  5400. </dd>
    5401. 

  5401. <dt>&lsquo;<samp>mbd</samp>&rsquo;</dt>
    5402. 

  5402. <dd><p>Set macroblock decision algorithm. Possible values in the increasing
    5403. 

  5403. order of quality:
    5404. 

  5404. </p>
    5405. 

  5405. <dl compact="compact">
    5406. 

  5406. <dt>&lsquo;<samp>simple</samp>&rsquo;</dt>
    5407. 

  5407. <dd><p>Use macroblock comparing function algorithm (default).
    5408. 

  5408. </p>
    5409. 

  5409. </dd>
    5410. 

  5410. <dt>&lsquo;<samp>bits</samp>&rsquo;</dt>
    5411. 

  5411. <dd><p>Enable rate distortion-based half pixel and quarter pixel refinement for
    5412. 

  5412. 16x16 blocks.
    5413. 

  5413. </p>
    5414. 

  5414. </dd>
    5415. 

  5415. <dt>&lsquo;<samp>rd</samp>&rsquo;</dt>
    5416. 

  5416. <dd><p>Enable all of the things described above, plus rate distortion-based
    5417. 

  5417. half pixel and quarter pixel refinement for 8x8 blocks, and rate
    5418. 

  5418. distortion-based search using square pattern.
    5419. 

  5419. </p></dd>
    5420. 

  5420. </dl>
    5421. 

  5421. 

  5422. </dd>
    5423. 

  5423. <dt>&lsquo;<samp>lumi_aq</samp>&rsquo;</dt>
    5424. 

  5424. <dd><p>Enable lumi masking adaptive quantization when set to 1. Default is 0
    5425. 

  5425. (disabled).
    5426. 

  5426. </p>
    5427. 

  5427. </dd>
    5428. 

  5428. <dt>&lsquo;<samp>variance_aq</samp>&rsquo;</dt>
    5429. 

  5429. <dd><p>Enable variance adaptive quantization when set to 1. Default is 0
    5430. 

  5430. (disabled).
    5431. 

  5431. </p>
    5432. 

  5432. <p>When combined with &lsquo;<samp>lumi_aq</samp>&rsquo;, the resulting quality will not
    5433. 

  5433. be better than any of the two specified individually. In other
    5434. 

  5434. words, the resulting quality will be the worse one of the two
    5435. 

  5435. effects.
    5436. 

  5436. </p>
    5437. 

  5437. </dd>
    5438. 

  5438. <dt>&lsquo;<samp>ssim</samp>&rsquo;</dt>
    5439. 

  5439. <dd><p>Set structural similarity (SSIM) displaying method. Possible values:
    5440. 

  5440. </p>
    5441. 

  5441. <dl compact="compact">
    5442. 

  5442. <dt>&lsquo;<samp>off</samp>&rsquo;</dt>
    5443. 

  5443. <dd><p>Disable displaying of SSIM information.
    5444. 

  5444. </p>
    5445. 

  5445. </dd>
    5446. 

  5446. <dt>&lsquo;<samp>avg</samp>&rsquo;</dt>
    5447. 

  5447. <dd><p>Output average SSIM at the end of encoding to stdout. The format of
    5448. 

  5448. showing the average SSIM is:
    5449. 

  5449. </p>
    5450. 

  5450. <div class="example">
    5451. 

  5451. <pre class="example">Average SSIM: %f
    5452. 

  5452. </pre></div>
    5453. 

  5453. 

  5454. <p>For users who are not familiar with C, %f means a float number, or
    5455. 

  5455. a decimal (e.g. 0.939232).
    5456. 

  5456. </p>
    5457. 

  5457. </dd>
    5458. 

  5458. <dt>&lsquo;<samp>frame</samp>&rsquo;</dt>
    5459. 

  5459. <dd><p>Output both per-frame SSIM data during encoding and average SSIM at
    5460. 

  5460. the end of encoding to stdout. The format of per-frame information
    5461. 

  5461. is:
    5462. 

  5462. </p>
    5463. 

  5463. <div class="example">
    5464. 

  5464. <pre class="example">       SSIM: avg: %1.3f min: %1.3f max: %1.3f
    5465. 

  5465. </pre></div>
    5466. 

  5466. 

  5467. <p>For users who are not familiar with C, %1.3f means a float number
    5468. 

  5468. rounded to 3 digits after the dot (e.g. 0.932).
    5469. 

  5469. </p>
    5470. 

  5470. </dd>
    5471. 

  5471. </dl>
    5472. 

  5472. 

  5473. </dd>
    5474. 

  5474. <dt>&lsquo;<samp>ssim_acc</samp>&rsquo;</dt>
    5475. 

  5475. <dd><p>Set SSIM accuracy. Valid options are integers within the range of
    5476. 

  5476. 0-4, while 0 gives the most accurate result and 4 computes the
    5477. 

  5477. fastest.
    5478. 

  5478. </p>
    5479. 

  5479. </dd>
    5480. 

  5480. </dl>
    5481. 

  5481. 

  5482. <a name="MediaFoundation"></a>
    5483. 

  5483. <h2 class="section"><a href="ffmpeg-codecs.html#toc-MediaFoundation">9.14 MediaFoundation</a></h2>
    5484. 

  5484. 

  5485. <p>This provides wrappers to encoders (both audio and video) in the
    5486. 

  5486. MediaFoundation framework. It can access both SW and HW encoders.
    5487. 

  5487. Video encoders can take input in either of nv12 or yuv420p form
    5488. 

  5488. (some encoders support both, some support only either - in practice,
    5489. 

  5489. nv12 is the safer choice, especially among HW encoders).
    5490. 

  5490. </p>
    5491. 

  5491. <a name="mpeg2"></a>
    5492. 

  5492. <h2 class="section"><a href="ffmpeg-codecs.html#toc-mpeg2">9.15 mpeg2</a></h2>
    5493. 

  5493. 

  5494. <p>MPEG-2 video encoder.
    5495. 

  5495. </p>
    5496. 

  5496. <a name="Options-13"></a>
    5497. 

  5497. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-13">9.15.1 Options</a></h3>
    5498. 

  5498. 

  5499. <dl compact="compact">
    5500. 

  5500. <dt>&lsquo;<samp>profile <var>integer</var></samp>&rsquo;</dt>
    5501. 

  5501. <dd><p>Select the mpeg2 profile to encode:
    5502. 

  5502. </p>
    5503. 

  5503. <dl compact="compact">
    5504. 

  5504. <dt>&lsquo;<samp>422</samp>&rsquo;</dt>
    5505. 

  5505. <dt>&lsquo;<samp>main</samp>&rsquo;</dt>
    5506. 

  5506. <dt>&lsquo;<samp>ss</samp>&rsquo;</dt>
    5507. 

  5507. <dd><p>Spatially Scalable
    5508. 

  5508. </p></dd>
    5509. 

  5509. <dt>&lsquo;<samp>snr</samp>&rsquo;</dt>
    5510. 

  5510. <dd><p>SNR Scalable
    5511. 

  5511. </p></dd>
    5512. 

  5512. <dt>&lsquo;<samp>high</samp>&rsquo;</dt>
    5513. 

  5513. <dt>&lsquo;<samp>simple</samp>&rsquo;</dt>
    5514. 

  5514. </dl>
    5515. 

  5515. 

  5516. </dd>
    5517. 

  5517. <dt>&lsquo;<samp>seq_disp_ext <var>integer</var></samp>&rsquo;</dt>
    5518. 

  5518. <dd><p>Specifies if the encoder should write a sequence_display_extension to the
    5519. 

  5519. output.
    5520. 

  5520. </p><dl compact="compact">
    5521. 

  5521. <dt>&lsquo;<samp>-1</samp>&rsquo;</dt>
    5522. 

  5522. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    5523. 

  5523. <dd><p>Decide automatically to write it or not (this is the default) by checking if
    5524. 

  5524. the data to be written is different from the default or unspecified values.
    5525. 

  5525. </p></dd>
    5526. 

  5526. <dt>&lsquo;<samp>0</samp>&rsquo;</dt>
    5527. 

  5527. <dt>&lsquo;<samp>never</samp>&rsquo;</dt>
    5528. 

  5528. <dd><p>Never write it.
    5529. 

  5529. </p></dd>
    5530. 

  5530. <dt>&lsquo;<samp>1</samp>&rsquo;</dt>
    5531. 

  5531. <dt>&lsquo;<samp>always</samp>&rsquo;</dt>
    5532. 

  5532. <dd><p>Always write it.
    5533. 

  5533. </p></dd>
    5534. 

  5534. </dl>
    5535. 

  5535. </dd>
    5536. 

  5536. <dt>&lsquo;<samp>video_format <var>integer</var></samp>&rsquo;</dt>
    5537. 

  5537. <dd><p>Specifies the video_format written into the sequence display extension
    5538. 

  5538. indicating the source of the video pictures. The default is &lsquo;<samp>unspecified</samp>&rsquo;,
    5539. 

  5539. can be &lsquo;<samp>component</samp>&rsquo;, &lsquo;<samp>pal</samp>&rsquo;, &lsquo;<samp>ntsc</samp>&rsquo;, &lsquo;<samp>secam</samp>&rsquo; or &lsquo;<samp>mac</samp>&rsquo;.
    5540. 

  5540. For maximum compatibility, use &lsquo;<samp>component</samp>&rsquo;.
    5541. 

  5541. </p></dd>
    5542. 

  5542. <dt>&lsquo;<samp>a53cc <var>boolean</var></samp>&rsquo;</dt>
    5543. 

  5543. <dd><p>Import closed captions (which must be ATSC compatible format) into output.
    5544. 

  5544. Default is 1 (on).
    5545. 

  5545. </p></dd>
    5546. 

  5546. </dl>
    5547. 

  5547. 

  5548. <a name="png"></a>
    5549. 

  5549. <h2 class="section"><a href="ffmpeg-codecs.html#toc-png">9.16 png</a></h2>
    5550. 

  5550. 

  5551. <p>PNG image encoder.
    5552. 

  5552. </p>
    5553. 

  5553. <a name="Private-options-1"></a>
    5554. 

  5554. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Private-options-1">9.16.1 Private options</a></h3>
    5555. 

  5555. 

  5556. <dl compact="compact">
    5557. 

  5557. <dt>&lsquo;<samp>dpi <var>integer</var></samp>&rsquo;</dt>
    5558. 

  5558. <dd><p>Set physical density of pixels, in dots per inch, unset by default
    5559. 

  5559. </p></dd>
    5560. 

  5560. <dt>&lsquo;<samp>dpm <var>integer</var></samp>&rsquo;</dt>
    5561. 

  5561. <dd><p>Set physical density of pixels, in dots per meter, unset by default
    5562. 

  5562. </p></dd>
    5563. 

  5563. </dl>
    5564. 

  5564. 

  5565. <a name="ProRes"></a>
    5566. 

  5566. <h2 class="section"><a href="ffmpeg-codecs.html#toc-ProRes">9.17 ProRes</a></h2>
    5567. 

  5567. 

  5568. <p>Apple ProRes encoder.
    5569. 

  5569. </p>
    5570. 

  5570. <p>FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
    5571. 

  5571. The used encoder can be chosen with the <code>-vcodec</code> option.
    5572. 

  5572. </p>
    5573. 

  5573. <a name="Private-Options-for-prores_002dks"></a>
    5574. 

  5574. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Private-Options-for-prores_002dks">9.17.1 Private Options for prores-ks</a></h3>
    5575. 

  5575. 

  5576. <dl compact="compact">
    5577. 

  5577. <dt>&lsquo;<samp>profile <var>integer</var></samp>&rsquo;</dt>
    5578. 

  5578. <dd><p>Select the ProRes profile to encode
    5579. 

  5579. </p><dl compact="compact">
    5580. 

  5580. <dt>&lsquo;<samp>proxy</samp>&rsquo;</dt>
    5581. 

  5581. <dt>&lsquo;<samp>lt</samp>&rsquo;</dt>
    5582. 

  5582. <dt>&lsquo;<samp>standard</samp>&rsquo;</dt>
    5583. 

  5583. <dt>&lsquo;<samp>hq</samp>&rsquo;</dt>
    5584. 

  5584. <dt>&lsquo;<samp>4444</samp>&rsquo;</dt>
    5585. 

  5585. <dt>&lsquo;<samp>4444xq</samp>&rsquo;</dt>
    5586. 

  5586. </dl>
    5587. 

  5587. 

  5588. </dd>
    5589. 

  5589. <dt>&lsquo;<samp>quant_mat <var>integer</var></samp>&rsquo;</dt>
    5590. 

  5590. <dd><p>Select quantization matrix.
    5591. 

  5591. </p><dl compact="compact">
    5592. 

  5592. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    5593. 

  5593. <dt>&lsquo;<samp>default</samp>&rsquo;</dt>
    5594. 

  5594. <dt>&lsquo;<samp>proxy</samp>&rsquo;</dt>
    5595. 

  5595. <dt>&lsquo;<samp>lt</samp>&rsquo;</dt>
    5596. 

  5596. <dt>&lsquo;<samp>standard</samp>&rsquo;</dt>
    5597. 

  5597. <dt>&lsquo;<samp>hq</samp>&rsquo;</dt>
    5598. 

  5598. </dl>
    5599. 

  5599. <p>If set to <var>auto</var>, the matrix matching the profile will be picked.
    5600. 

  5600. If not set, the matrix providing the highest quality, <var>default</var>, will be
    5601. 

  5601. picked.
    5602. 

  5602. </p>
    5603. 

  5603. </dd>
    5604. 

  5604. <dt>&lsquo;<samp>bits_per_mb <var>integer</var></samp>&rsquo;</dt>
    5605. 

  5605. <dd><p>How many bits to allot for coding one macroblock. Different profiles use
    5606. 

  5606. between 200 and 2400 bits per macroblock, the maximum is 8000.
    5607. 

  5607. </p>
    5608. 

  5608. </dd>
    5609. 

  5609. <dt>&lsquo;<samp>mbs_per_slice <var>integer</var></samp>&rsquo;</dt>
    5610. 

  5610. <dd><p>Number of macroblocks in each slice (1-8); the default value (8)
    5611. 

  5611. should be good in almost all situations.
    5612. 

  5612. </p>
    5613. 

  5613. </dd>
    5614. 

  5614. <dt>&lsquo;<samp>vendor <var>string</var></samp>&rsquo;</dt>
    5615. 

  5615. <dd><p>Override the 4-byte vendor ID.
    5616. 

  5616. A custom vendor ID like <var>apl0</var> would claim the stream was produced by
    5617. 

  5617. the Apple encoder.
    5618. 

  5618. </p>
    5619. 

  5619. </dd>
    5620. 

  5620. <dt>&lsquo;<samp>alpha_bits <var>integer</var></samp>&rsquo;</dt>
    5621. 

  5621. <dd><p>Specify number of bits for alpha component.
    5622. 

  5622. Possible values are <var>0</var>, <var>8</var> and <var>16</var>.
    5623. 

  5623. Use <var>0</var> to disable alpha plane coding.
    5624. 

  5624. </p>
    5625. 

  5625. </dd>
    5626. 

  5626. </dl>
    5627. 

  5627. 

  5628. <a name="Speed-considerations"></a>
    5629. 

  5629. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Speed-considerations">9.17.2 Speed considerations</a></h3>
    5630. 

  5630. 

  5631. <p>In the default mode of operation the encoder has to honor frame constraints
    5632. 

  5632. (i.e. not produce frames with size bigger than requested) while still making
    5633. 

  5633. output picture as good as possible.
    5634. 

  5634. A frame containing a lot of small details is harder to compress and the encoder
    5635. 

  5635. would spend more time searching for appropriate quantizers for each slice.
    5636. 

  5636. </p>
    5637. 

  5637. <p>Setting a higher &lsquo;<samp>bits_per_mb</samp>&rsquo; limit will improve the speed.
    5638. 

  5638. </p>
    5639. 

  5639. <p>For the fastest encoding speed set the &lsquo;<samp>qscale</samp>&rsquo; parameter (4 is the
    5640. 

  5640. recommended value) and do not set a size constraint.
    5641. 

  5641. </p>
    5642. 

  5642. <a name="QSV-encoders"></a>
    5643. 

  5643. <h2 class="section"><a href="ffmpeg-codecs.html#toc-QSV-encoders">9.18 QSV encoders</a></h2>
    5644. 

  5644. 

  5645. <p>The family of Intel QuickSync Video encoders (MPEG-2, H.264, HEVC, JPEG/MJPEG and VP9)
    5646. 

  5646. </p>
    5647. 

  5647. <p>The ratecontrol method is selected as follows:
    5648. 

  5648. </p>
    5649. 

  5649. <ul>
    5650. 

  5650. <li>
    5651. 

  5651. When &lsquo;<samp>global_quality</samp>&rsquo; is specified, a quality-based mode is used.
    5652. 

  5652. Specifically this means either
    5653. 

  5653. <ul class="no-bullet">
    5654. 

  5654. <li>-
    5655. 

  5655. <var>CQP</var> - constant quantizer scale, when the &lsquo;<samp>qscale</samp>&rsquo; codec flag is
    5656. 

  5656. also set (the &lsquo;<samp>-qscale</samp>&rsquo; ffmpeg option).
    5657. 

  5657. 

  5658. </li><li>-
    5659. 

  5659. <var>LA_ICQ</var> - intelligent constant quality with lookahead, when the
    5660. 

  5660. &lsquo;<samp>look_ahead</samp>&rsquo; option is also set.
    5661. 

  5661. 

  5662. </li><li>-
    5663. 

  5663. <var>ICQ</var> &ndash; intelligent constant quality otherwise.
    5664. 

  5664. </li></ul>
    5665. 

  5665. 

  5666. </li><li>
    5667. 

  5667. Otherwise, a bitrate-based mode is used. For all of those, you should specify at
    5668. 

  5668. least the desired average bitrate with the &lsquo;<samp>b</samp>&rsquo; option.
    5669. 

  5669. <ul class="no-bullet">
    5670. 

  5670. <li>-
    5671. 

  5671. <var>LA</var> - VBR with lookahead, when the &lsquo;<samp>look_ahead</samp>&rsquo; option is specified.
    5672. 

  5672. 

  5673. </li><li>-
    5674. 

  5674. <var>VCM</var> - video conferencing mode, when the &lsquo;<samp>vcm</samp>&rsquo; option is set.
    5675. 

  5675. 

  5676. </li><li>-
    5677. 

  5677. <var>CBR</var> - constant bitrate, when &lsquo;<samp>maxrate</samp>&rsquo; is specified and equal to
    5678. 

  5678. the average bitrate.
    5679. 

  5679. 

  5680. </li><li>-
    5681. 

  5681. <var>VBR</var> - variable bitrate, when &lsquo;<samp>maxrate</samp>&rsquo; is specified, but is higher
    5682. 

  5682. than the average bitrate.
    5683. 

  5683. 

  5684. </li><li>-
    5685. 

  5685. <var>AVBR</var> - average VBR mode, when &lsquo;<samp>maxrate</samp>&rsquo; is not specified. This mode
    5686. 

  5686. is further configured by the &lsquo;<samp>avbr_accuracy</samp>&rsquo; and
    5687. 

  5687. &lsquo;<samp>avbr_convergence</samp>&rsquo; options.
    5688. 

  5688. </li></ul>
    5689. 

  5689. </li></ul>
    5690. 

  5690. 

  5691. <p>Note that depending on your system, a different mode than the one you specified
    5692. 

  5692. may be selected by the encoder. Set the verbosity level to <var>verbose</var> or
    5693. 

  5693. higher to see the actual settings used by the QSV runtime.
    5694. 

  5694. </p>
    5695. 

  5695. <p>Additional libavcodec global options are mapped to MSDK options as follows:
    5696. 

  5696. </p>
    5697. 

  5697. <ul>
    5698. 

  5698. <li>
    5699. 

  5699. &lsquo;<samp>g/gop_size</samp>&rsquo; -&gt; &lsquo;<samp>GopPicSize</samp>&rsquo;
    5700. 

  5700. 

  5701. </li><li>
    5702. 

  5702. &lsquo;<samp>bf/max_b_frames</samp>&rsquo;+1 -&gt; &lsquo;<samp>GopRefDist</samp>&rsquo;
    5703. 

  5703. 

  5704. </li><li>
    5705. 

  5705. &lsquo;<samp>rc_init_occupancy/rc_initial_buffer_occupancy</samp>&rsquo; -&gt;
    5706. 

  5706. &lsquo;<samp>InitialDelayInKB</samp>&rsquo;
    5707. 

  5707. 

  5708. </li><li>
    5709. 

  5709. &lsquo;<samp>slices</samp>&rsquo; -&gt; &lsquo;<samp>NumSlice</samp>&rsquo;
    5710. 

  5710. 

  5711. </li><li>
    5712. 

  5712. &lsquo;<samp>refs</samp>&rsquo; -&gt; &lsquo;<samp>NumRefFrame</samp>&rsquo;
    5713. 

  5713. 

  5714. </li><li>
    5715. 

  5715. &lsquo;<samp>b_strategy/b_frame_strategy</samp>&rsquo; -&gt; &lsquo;<samp>BRefType</samp>&rsquo;
    5716. 

  5716. 

  5717. </li><li>
    5718. 

  5718. &lsquo;<samp>cgop/CLOSED_GOP</samp>&rsquo; codec flag -&gt; &lsquo;<samp>GopOptFlag</samp>&rsquo;
    5719. 

  5719. 

  5720. </li><li>
    5721. 

  5721. For the <var>CQP</var> mode, the &lsquo;<samp>i_qfactor/i_qoffset</samp>&rsquo; and
    5722. 

  5722. &lsquo;<samp>b_qfactor/b_qoffset</samp>&rsquo; set the difference between <var>QPP</var> and <var>QPI</var>,
    5723. 

  5723. and <var>QPP</var> and <var>QPB</var> respectively.
    5724. 

  5724. 

  5725. </li><li>
    5726. 

  5726. Setting the &lsquo;<samp>coder</samp>&rsquo; option to the value <var>vlc</var> will make the H.264
    5727. 

  5727. encoder use CAVLC instead of CABAC.
    5728. 

  5728. 

  5729. </li></ul>
    5730. 

  5730. 

  5731. <a name="snow"></a>
    5732. 

  5732. <h2 class="section"><a href="ffmpeg-codecs.html#toc-snow">9.19 snow</a></h2>
    5733. 

  5733. 

  5734. <a name="Options-15"></a>
    5735. 

  5735. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-15">9.19.1 Options</a></h3>
    5736. 

  5736. 

  5737. <dl compact="compact">
    5738. 

  5738. <dt>&lsquo;<samp>iterative_dia_size</samp>&rsquo;</dt>
    5739. 

  5739. <dd><p>dia size for the iterative motion estimation
    5740. 

  5740. </p></dd>
    5741. 

  5741. </dl>
    5742. 

  5742. 

  5743. <a name="VAAPI-encoders"></a>
    5744. 

  5744. <h2 class="section"><a href="ffmpeg-codecs.html#toc-VAAPI-encoders">9.20 VAAPI encoders</a></h2>
    5745. 

  5745. 

  5746. <p>Wrappers for hardware encoders accessible via VAAPI.
    5747. 

  5747. </p>
    5748. 

  5748. <p>These encoders only accept input in VAAPI hardware surfaces.  If you have input
    5749. 

  5749. in software frames, use the &lsquo;<samp>hwupload</samp>&rsquo; filter to upload them to the GPU.
    5750. 

  5750. </p>
    5751. 

  5751. <p>The following standard libavcodec options are used:
    5752. 

  5752. </p><ul>
    5753. 

  5753. <li>
    5754. 

  5754. &lsquo;<samp>g</samp>&rsquo; / &lsquo;<samp>gop_size</samp>&rsquo;
    5755. 

  5755. </li><li>
    5756. 

  5756. &lsquo;<samp>bf</samp>&rsquo; / &lsquo;<samp>max_b_frames</samp>&rsquo;
    5757. 

  5757. </li><li>
    5758. 

  5758. &lsquo;<samp>profile</samp>&rsquo;
    5759. 

  5759. 

  5760. <p>If not set, this will be determined automatically from the format of the input
    5761. 

  5761. frames and the profiles supported by the driver.
    5762. 

  5762. </p></li><li>
    5763. 

  5763. &lsquo;<samp>level</samp>&rsquo;
    5764. 

  5764. </li><li>
    5765. 

  5765. &lsquo;<samp>b</samp>&rsquo; / &lsquo;<samp>bit_rate</samp>&rsquo;
    5766. 

  5766. </li><li>
    5767. 

  5767. &lsquo;<samp>maxrate</samp>&rsquo; / &lsquo;<samp>rc_max_rate</samp>&rsquo;
    5768. 

  5768. </li><li>
    5769. 

  5769. &lsquo;<samp>bufsize</samp>&rsquo; / &lsquo;<samp>rc_buffer_size</samp>&rsquo;
    5770. 

  5770. </li><li>
    5771. 

  5771. &lsquo;<samp>rc_init_occupancy</samp>&rsquo; / &lsquo;<samp>rc_initial_buffer_occupancy</samp>&rsquo;
    5772. 

  5772. </li><li>
    5773. 

  5773. &lsquo;<samp>compression_level</samp>&rsquo;
    5774. 

  5774. 

  5775. <p>Speed / quality tradeoff: higher values are faster / worse quality.
    5776. 

  5776. </p></li><li>
    5777. 

  5777. &lsquo;<samp>q</samp>&rsquo; / &lsquo;<samp>global_quality</samp>&rsquo;
    5778. 

  5778. 

  5779. <p>Size / quality tradeoff: higher values are smaller / worse quality.
    5780. 

  5780. </p></li><li>
    5781. 

  5781. &lsquo;<samp>qmin</samp>&rsquo;
    5782. 

  5782. </li><li>
    5783. 

  5783. &lsquo;<samp>qmax</samp>&rsquo;
    5784. 

  5784. </li><li>
    5785. 

  5785. &lsquo;<samp>i_qfactor</samp>&rsquo; / &lsquo;<samp>i_quant_factor</samp>&rsquo;
    5786. 

  5786. </li><li>
    5787. 

  5787. &lsquo;<samp>i_qoffset</samp>&rsquo; / &lsquo;<samp>i_quant_offset</samp>&rsquo;
    5788. 

  5788. </li><li>
    5789. 

  5789. &lsquo;<samp>b_qfactor</samp>&rsquo; / &lsquo;<samp>b_quant_factor</samp>&rsquo;
    5790. 

  5790. </li><li>
    5791. 

  5791. &lsquo;<samp>b_qoffset</samp>&rsquo; / &lsquo;<samp>b_quant_offset</samp>&rsquo;
    5792. 

  5792. </li><li>
    5793. 

  5793. &lsquo;<samp>slices</samp>&rsquo;
    5794. 

  5794. </li></ul>
    5795. 

  5795. 

  5796. <p>All encoders support the following options:
    5797. 

  5797. </p><dl compact="compact">
    5798. 

  5798. <dt>&lsquo;<samp>low_power</samp>&rsquo;</dt>
    5799. 

  5799. <dd><p>Some drivers/platforms offer a second encoder for some codecs intended to use
    5800. 

  5800. less power than the default encoder; setting this option will attempt to use
    5801. 

  5801. that encoder.  Note that it may support a reduced feature set, so some other
    5802. 

  5802. options may not be available in this mode.
    5803. 

  5803. </p>
    5804. 

  5804. </dd>
    5805. 

  5805. <dt>&lsquo;<samp>idr_interval</samp>&rsquo;</dt>
    5806. 

  5806. <dd><p>Set the number of normal intra frames between full-refresh (IDR) frames in
    5807. 

  5807. open-GOP mode.  The intra frames are still IRAPs, but will not include global
    5808. 

  5808. headers and may have non-decodable leading pictures.
    5809. 

  5809. </p>
    5810. 

  5810. </dd>
    5811. 

  5811. <dt>&lsquo;<samp>b_depth</samp>&rsquo;</dt>
    5812. 

  5812. <dd><p>Set the B-frame reference depth.  When set to one (the default), all B-frames
    5813. 

  5813. will refer only to P- or I-frames.  When set to greater values multiple layers
    5814. 

  5814. of B-frames will be present, frames in each layer only referring to frames in
    5815. 

  5815. higher layers.
    5816. 

  5816. </p>
    5817. 

  5817. </dd>
    5818. 

  5818. <dt>&lsquo;<samp>rc_mode</samp>&rsquo;</dt>
    5819. 

  5819. <dd><p>Set the rate control mode to use.  A given driver may only support a subset of
    5820. 

  5820. modes.
    5821. 

  5821. </p>
    5822. 

  5822. <p>Possible modes:
    5823. 

  5823. </p><dl compact="compact">
    5824. 

  5824. <dt>&lsquo;<samp>auto</samp>&rsquo;</dt>
    5825. 

  5825. <dd><p>Choose the mode automatically based on driver support and the other options.
    5826. 

  5826. This is the default.
    5827. 

  5827. </p></dd>
    5828. 

  5828. <dt>&lsquo;<samp>CQP</samp>&rsquo;</dt>
    5829. 

  5829. <dd><p>Constant-quality.
    5830. 

  5830. </p></dd>
    5831. 

  5831. <dt>&lsquo;<samp>CBR</samp>&rsquo;</dt>
    5832. 

  5832. <dd><p>Constant-bitrate.
    5833. 

  5833. </p></dd>
    5834. 

  5834. <dt>&lsquo;<samp>VBR</samp>&rsquo;</dt>
    5835. 

  5835. <dd><p>Variable-bitrate.
    5836. 

  5836. </p></dd>
    5837. 

  5837. <dt>&lsquo;<samp>ICQ</samp>&rsquo;</dt>
    5838. 

  5838. <dd><p>Intelligent constant-quality.
    5839. 

  5839. </p></dd>
    5840. 

  5840. <dt>&lsquo;<samp>QVBR</samp>&rsquo;</dt>
    5841. 

  5841. <dd><p>Quality-defined variable-bitrate.
    5842. 

  5842. </p></dd>
    5843. 

  5843. <dt>&lsquo;<samp>AVBR</samp>&rsquo;</dt>
    5844. 

  5844. <dd><p>Average variable bitrate.
    5845. 

  5845. </p></dd>
    5846. 

  5846. </dl>
    5847. 

  5847. 

  5848. </dd>
    5849. 

  5849. </dl>
    5850. 

  5850. 

  5851. <p>Each encoder also has its own specific options:
    5852. 

  5852. </p><dl compact="compact">
    5853. 

  5853. <dt>&lsquo;<samp>h264_vaapi</samp>&rsquo;</dt>
    5854. 

  5854. <dd><p>&lsquo;<samp>profile</samp>&rsquo; sets the value of <em>profile_idc</em> and the <em>constraint_set*_flag</em>s.
    5855. 

  5855. &lsquo;<samp>level</samp>&rsquo; sets the value of <em>level_idc</em>.
    5856. 

  5856. </p>
    5857. 

  5857. <dl compact="compact">
    5858. 

  5858. <dt>&lsquo;<samp>coder</samp>&rsquo;</dt>
    5859. 

  5859. <dd><p>Set entropy encoder (default is <em>cabac</em>).  Possible values:
    5860. 

  5860. </p>
    5861. 

  5861. <dl compact="compact">
    5862. 

  5862. <dt>&lsquo;<samp>ac</samp>&rsquo;</dt>
    5863. 

  5863. <dt>&lsquo;<samp>cabac</samp>&rsquo;</dt>
    5864. 

  5864. <dd><p>Use CABAC.
    5865. 

  5865. </p>
    5866. 

  5866. </dd>
    5867. 

  5867. <dt>&lsquo;<samp>vlc</samp>&rsquo;</dt>
    5868. 

  5868. <dt>&lsquo;<samp>cavlc</samp>&rsquo;</dt>
    5869. 

  5869. <dd><p>Use CAVLC.
    5870. 

  5870. </p></dd>
    5871. 

  5871. </dl>
    5872. 

  5872. 

  5873. </dd>
    5874. 

  5874. <dt>&lsquo;<samp>aud</samp>&rsquo;</dt>
    5875. 

  5875. <dd><p>Include access unit delimiters in the stream (not included by default).
    5876. 

  5876. </p>
    5877. 

  5877. </dd>
    5878. 

  5878. <dt>&lsquo;<samp>sei</samp>&rsquo;</dt>
    5879. 

  5879. <dd><p>Set SEI message types to include.
    5880. 

  5880. Some combination of the following values:
    5881. 

  5881. </p><dl compact="compact">
    5882. 

  5882. <dt>&lsquo;<samp>identifier</samp>&rsquo;</dt>
    5883. 

  5883. <dd><p>Include a <em>user_data_unregistered</em> message containing information about
    5884. 

  5884. the encoder.
    5885. 

  5885. </p></dd>
    5886. 

  5886. <dt>&lsquo;<samp>timing</samp>&rsquo;</dt>
    5887. 

  5887. <dd><p>Include picture timing parameters (<em>buffering_period</em> and
    5888. 

  5888. <em>pic_timing</em> messages).
    5889. 

  5889. </p></dd>
    5890. 

  5890. <dt>&lsquo;<samp>recovery_point</samp>&rsquo;</dt>
    5891. 

  5891. <dd><p>Include recovery points where appropriate (<em>recovery_point</em> messages).
    5892. 

  5892. </p></dd>
    5893. 

  5893. </dl>
    5894. 

  5894. 

  5895. </dd>
    5896. 

  5896. </dl>
    5897. 

  5897. 

  5898. </dd>
    5899. 

  5899. <dt>&lsquo;<samp>hevc_vaapi</samp>&rsquo;</dt>
    5900. 

  5900. <dd><p>&lsquo;<samp>profile</samp>&rsquo; and &lsquo;<samp>level</samp>&rsquo; set the values of
    5901. 

  5901. <em>general_profile_idc</em> and <em>general_level_idc</em> respectively.
    5902. 

  5902. </p>
    5903. 

  5903. <dl compact="compact">
    5904. 

  5904. <dt>&lsquo;<samp>aud</samp>&rsquo;</dt>
    5905. 

  5905. <dd><p>Include access unit delimiters in the stream (not included by default).
    5906. 

  5906. </p>
    5907. 

  5907. </dd>
    5908. 

  5908. <dt>&lsquo;<samp>tier</samp>&rsquo;</dt>
    5909. 

  5909. <dd><p>Set <em>general_tier_flag</em>.  This may affect the level chosen for the stream
    5910. 

  5910. if it is not explicitly specified.
    5911. 

  5911. </p>
    5912. 

  5912. </dd>
    5913. 

  5913. <dt>&lsquo;<samp>sei</samp>&rsquo;</dt>
    5914. 

  5914. <dd><p>Set SEI message types to include.
    5915. 

  5915. Some combination of the following values:
    5916. 

  5916. </p><dl compact="compact">
    5917. 

  5917. <dt>&lsquo;<samp>hdr</samp>&rsquo;</dt>
    5918. 

  5918. <dd><p>Include HDR metadata if the input frames have it
    5919. 

  5919. (<em>mastering_display_colour_volume</em> and <em>content_light_level</em>
    5920. 

  5920. messages).
    5921. 

  5921. </p></dd>
    5922. 

  5922. </dl>
    5923. 

  5923. 

  5924. </dd>
    5925. 

  5925. </dl>
    5926. 

  5926. 

  5927. </dd>
    5928. 

  5928. <dt>&lsquo;<samp>mjpeg_vaapi</samp>&rsquo;</dt>
    5929. 

  5929. <dd><p>Only baseline DCT encoding is supported.  The encoder always uses the standard
    5930. 

  5930. quantisation and huffman tables - &lsquo;<samp>global_quality</samp>&rsquo; scales the standard
    5931. 

  5931. quantisation table (range 1-100).
    5932. 

  5932. </p>
    5933. 

  5933. <p>For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported.  RGB is also
    5934. 

  5934. supported, and will create an RGB JPEG.
    5935. 

  5935. </p>
    5936. 

  5936. <dl compact="compact">
    5937. 

  5937. <dt>&lsquo;<samp>jfif</samp>&rsquo;</dt>
    5938. 

  5938. <dd><p>Include JFIF header in each frame (not included by default).
    5939. 

  5939. </p></dd>
    5940. 

  5940. <dt>&lsquo;<samp>huffman</samp>&rsquo;</dt>
    5941. 

  5941. <dd><p>Include standard huffman tables (on by default).  Turning this off will save
    5942. 

  5942. a few hundred bytes in each output frame, but may lose compatibility with some
    5943. 

  5943. JPEG decoders which don&rsquo;t fully handle MJPEG.
    5944. 

  5944. </p></dd>
    5945. 

  5945. </dl>
    5946. 

  5946. 

  5947. </dd>
    5948. 

  5948. <dt>&lsquo;<samp>mpeg2_vaapi</samp>&rsquo;</dt>
    5949. 

  5949. <dd><p>&lsquo;<samp>profile</samp>&rsquo; and &lsquo;<samp>level</samp>&rsquo; set the value of <em>profile_and_level_indication</em>.
    5950. 

  5950. </p>
    5951. 

  5951. </dd>
    5952. 

  5952. <dt>&lsquo;<samp>vp8_vaapi</samp>&rsquo;</dt>
    5953. 

  5953. <dd><p>B-frames are not supported.
    5954. 

  5954. </p>
    5955. 

  5955. <p>&lsquo;<samp>global_quality</samp>&rsquo; sets the <em>q_idx</em> used for non-key frames (range 0-127).
    5956. 

  5956. </p>
    5957. 

  5957. <dl compact="compact">
    5958. 

  5958. <dt>&lsquo;<samp>loop_filter_level</samp>&rsquo;</dt>
    5959. 

  5959. <dt>&lsquo;<samp>loop_filter_sharpness</samp>&rsquo;</dt>
    5960. 

  5960. <dd><p>Manually set the loop filter parameters.
    5961. 

  5961. </p></dd>
    5962. 

  5962. </dl>
    5963. 

  5963. 

  5964. </dd>
    5965. 

  5965. <dt>&lsquo;<samp>vp9_vaapi</samp>&rsquo;</dt>
    5966. 

  5966. <dd><p>&lsquo;<samp>global_quality</samp>&rsquo; sets the <em>q_idx</em> used for P-frames (range 0-255).
    5967. 

  5967. </p>
    5968. 

  5968. <dl compact="compact">
    5969. 

  5969. <dt>&lsquo;<samp>loop_filter_level</samp>&rsquo;</dt>
    5970. 

  5970. <dt>&lsquo;<samp>loop_filter_sharpness</samp>&rsquo;</dt>
    5971. 

  5971. <dd><p>Manually set the loop filter parameters.
    5972. 

  5972. </p></dd>
    5973. 

  5973. </dl>
    5974. 

  5974. 

  5975. <p>B-frames are supported, but the output stream is always in encode order rather than display
    5976. 

  5976. order.  If B-frames are enabled, it may be necessary to use the &lsquo;<samp>vp9_raw_reorder</samp>&rsquo;
    5977. 

  5977. bitstream filter to modify the output stream to display frames in the correct order.
    5978. 

  5978. </p>
    5979. 

  5979. <p>Only normal frames are produced - the &lsquo;<samp>vp9_superframe</samp>&rsquo; bitstream filter may be
    5980. 

  5980. required to produce a stream usable with all decoders.
    5981. 

  5981. </p>
    5982. 

  5982. </dd>
    5983. 

  5983. </dl>
    5984. 

  5984. 

  5985. <a name="vc2"></a>
    5986. 

  5986. <h2 class="section"><a href="ffmpeg-codecs.html#toc-vc2">9.21 vc2</a></h2>
    5987. 

  5987. 

  5988. <p>SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
    5989. 

  5989. professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
    5990. 

  5990. 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
    5991. 

  5991. other tasks which require low overhead and low compression (like screen
    5992. 

  5992. recording).
    5993. 

  5993. </p>
    5994. 

  5994. <a name="Options-18"></a>
    5995. 

  5995. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-18">9.21.1 Options</a></h3>
    5996. 

  5996. 

  5997. <dl compact="compact">
    5998. 

  5998. <dt>&lsquo;<samp>b</samp>&rsquo;</dt>
    5999. 

  5999. <dd><p>Sets target video bitrate. Usually that&rsquo;s around 1:6 of the uncompressed
    6000. 

  6000. video bitrate (e.g. for 1920x1080 50fps yuv422p10 that&rsquo;s around 400Mbps). Higher
    6001. 

  6001. values (close to the uncompressed bitrate) turn on lossless compression mode.
    6002. 

  6002. </p>
    6003. 

  6003. </dd>
    6004. 

  6004. <dt>&lsquo;<samp>field_order</samp>&rsquo;</dt>
    6005. 

  6005. <dd><p>Enables field coding when set (e.g. to tt - top field first) for interlaced
    6006. 

  6006. inputs. Should increase compression with interlaced content as it splits the
    6007. 

  6007. fields and encodes each separately.
    6008. 

  6008. </p>
    6009. 

  6009. </dd>
    6010. 

  6010. <dt>&lsquo;<samp>wavelet_depth</samp>&rsquo;</dt>
    6011. 

  6011. <dd><p>Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
    6012. 

  6012. Lower values reduce compression and quality. Less capable decoders may not be
    6013. 

  6013. able to handle values of &lsquo;<samp>wavelet_depth</samp>&rsquo; over 3.
    6014. 

  6014. </p>
    6015. 

  6015. </dd>
    6016. 

  6016. <dt>&lsquo;<samp>wavelet_type</samp>&rsquo;</dt>
    6017. 

  6017. <dd><p>Sets the transform type. Currently only <var>5_3</var> (LeGall) and <var>9_7</var>
    6018. 

  6018. (Deslauriers-Dubuc)
    6019. 

  6019. are implemented, with 9_7 being the one with better compression and thus
    6020. 

  6020. is the default.
    6021. 

  6021. </p>
    6022. 

  6022. </dd>
    6023. 

  6023. <dt>&lsquo;<samp>slice_width</samp>&rsquo;</dt>
    6024. 

  6024. <dt>&lsquo;<samp>slice_height</samp>&rsquo;</dt>
    6025. 

  6025. <dd><p>Sets the slice size for each slice. Larger values result in better compression.
    6026. 

  6026. For compatibility with other more limited decoders use &lsquo;<samp>slice_width</samp>&rsquo; of
    6027. 

  6027. 32 and &lsquo;<samp>slice_height</samp>&rsquo; of 8.
    6028. 

  6028. </p>
    6029. 

  6029. </dd>
    6030. 

  6030. <dt>&lsquo;<samp>tolerance</samp>&rsquo;</dt>
    6031. 

  6031. <dd><p>Sets the undershoot tolerance of the rate control system in percent. This is
    6032. 

  6032. to prevent an expensive search from being run.
    6033. 

  6033. </p>
    6034. 

  6034. </dd>
    6035. 

  6035. <dt>&lsquo;<samp>qm</samp>&rsquo;</dt>
    6036. 

  6036. <dd><p>Sets the quantization matrix preset to use by default or when &lsquo;<samp>wavelet_depth</samp>&rsquo;
    6037. 

  6037. is set to 5
    6038. 

  6038. </p><ul class="no-bullet">
    6039. 

  6039. <li>-
    6040. 

  6040. <var>default</var>
    6041. 

  6041. Uses the default quantization matrix from the specifications, extended with
    6042. 

  6042. values for the fifth level. This provides a good balance between keeping detail
    6043. 

  6043. and omitting artifacts.
    6044. 

  6044. 

  6045. </li><li>-
    6046. 

  6046. <var>flat</var>
    6047. 

  6047. Use a completely zeroed out quantization matrix. This increases PSNR but might
    6048. 

  6048. reduce perception. Use in bogus benchmarks.
    6049. 

  6049. 

  6050. </li><li>-
    6051. 

  6051. <var>color</var>
    6052. 

  6052. Reduces detail but attempts to preserve color at extremely low bitrates.
    6053. 

  6053. </li></ul>
    6054. 

  6054. 

  6055. </dd>
    6056. 

  6056. </dl>
    6057. 

  6057. 

  6058. 

  6059. <a name="Subtitles-Encoders"></a>
    6060. 

  6060. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Subtitles-Encoders">10 Subtitles Encoders</a></h1>
    6061. 

  6061. 

  6062. <a name="dvdsub-1"></a>
    6063. 

  6063. <h2 class="section"><a href="ffmpeg-codecs.html#toc-dvdsub-1">10.1 dvdsub</a></h2>
    6064. 

  6064. 

  6065. <p>This codec encodes the bitmap subtitle format that is used in DVDs.
    6066. 

  6066. Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
    6067. 

  6067. and they can also be used in Matroska files.
    6068. 

  6068. </p>
    6069. 

  6069. <a name="Options-21"></a>
    6070. 

  6070. <h3 class="subsection"><a href="ffmpeg-codecs.html#toc-Options-21">10.1.1 Options</a></h3>
    6071. 

  6071. 

  6072. <dl compact="compact">
    6073. 

  6073. <dt>&lsquo;<samp>palette</samp>&rsquo;</dt>
    6074. 

  6074. <dd><p>Specify the global palette used by the bitmaps.
    6075. 

  6075. </p>
    6076. 

  6076. <p>The format for this option is a string containing 16 24-bits hexadecimal
    6077. 

  6077. numbers (without 0x prefix) separated by commas, for example <code>0d00ee,
    6078. 

  6078. ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,
    6079. 

  6079. 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b</code>.
    6080. 

  6080. </p>
    6081. 

  6081. </dd>
    6082. 

  6082. <dt>&lsquo;<samp>even_rows_fix</samp>&rsquo;</dt>
    6083. 

  6083. <dd><p>When set to 1, enable a work-around that makes the number of pixel rows
    6084. 

  6084. even in all subtitles.  This fixes a problem with some players that
    6085. 

  6085. cut off the bottom row if the number is odd.  The work-around just adds
    6086. 

  6086. a fully transparent row if needed.  The overhead is low, typically
    6087. 

  6087. one byte per subtitle on average.
    6088. 

  6088. </p>
    6089. 

  6089. <p>By default, this work-around is disabled.
    6090. 

  6090. </p></dd>
    6091. 

  6091. </dl>
    6092. 

  6092. 

  6093. 

  6094. <a name="See-Also"></a>
    6095. 

  6095. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-See-Also">11 See Also</a></h1>
    6096. 

  6096. 

  6097. <p><a href="ffmpeg.html">ffmpeg</a>, <a href="ffplay.html">ffplay</a>, <a href="ffprobe.html">ffprobe</a>,
    6098. 

  6098. <a href="libavcodec.html">libavcodec</a>
    6099. 

  6099. </p>
    6100. 

  6100. 

  6101. <a name="Authors"></a>
    6102. 

  6102. <h1 class="chapter"><a href="ffmpeg-codecs.html#toc-Authors">12 Authors</a></h1>
    6103. 

  6103. 

  6104. <p>The FFmpeg developers.
    6105. 

  6105. </p>
    6106. 

  6106. <p>For details about the authorship, see the Git history of the project
    6107. 

  6107. (git://source.ffmpeg.org/ffmpeg), e.g. by typing the command
    6108. 

  6108. <code>git log</code> in the FFmpeg source directory, or browsing the
    6109. 

  6109. online repository at <a href="http://source.ffmpeg.org">http://source.ffmpeg.org</a>.
    6110. 

  6110. </p>
    6111. 

  6111. <p>Maintainers for the specific components are listed in the file
    6112. 

  6112. &lsquo;<tt>MAINTAINERS</tt>&rsquo; in the source code tree.
    6113. 

  6113. </p>
    6114. 

  6114. 

  6115.     </div>
    6116. 

  6116.   </body>
    6117. 

  6117. </html>
    6118. 

  6118.