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\input texinfo @c -*- texinfo -*-
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@settitle General Documentation
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@titlepage
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@sp 7
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@center @titlefont{General Documentation}
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@sp 3
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@end titlepage
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@chapter external libraries
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FFmpeg can be hooked up with a number of external libraries to add support
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for more formats. None of them are used by default, their use has to be
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explicitly requested by passing the appropriate flags to @file{./configure}.
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@section AMR
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AMR comes in two different flavors, wideband and narrowband. FFmpeg can make
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use of the AMR wideband (floating-point mode) and the AMR narrowband
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(floating-point mode) reference decoders and encoders.
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Go to @url{http://www.penguin.cz/~utx/amr} and follow the instructions for
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installing the libraries. Then pass @code{--enable-libamr-nb} and/or
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@code{--enable-libamr-wb} to configure to enable the libraries.
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Note that libamr is copyrighted without any sort of license grant. This means
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that you can use it if you legally obtained it but you are not allowed to
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redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
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you create are non-free and unredistributable!}
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@chapter Supported File Formats and Codecs
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You can use the @code{-formats} option to have an exhaustive list.
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@section File Formats
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FFmpeg supports the following file formats through the @code{libavformat}
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library:
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@multitable @columnfractions .4 .1 .1 .4
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@item Name @tab Encoding @tab Decoding @tab Comments
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@item 4xm                       @tab   @tab X
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    @tab 4X Technologies format, used in some games.
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@item Audio IFF (AIFF)          @tab X @tab X
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@item American Laser Games MM   @tab   @tab X
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    @tab Multimedia format used in games like Mad Dog McCree.
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@item 3GPP AMR                  @tab X @tab X
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@item ASF                       @tab X @tab X
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@item AVI                       @tab X @tab X
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@item AVISynth                  @tab   @tab X
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@item AVS                       @tab   @tab X
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    @tab Multimedia format used by the Creature Shock game.
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@item Beam Software SIFF        @tab   @tab X
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    @tab Audio and video format used in some games by Beam Software.
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@item Bethesda Softworks VID    @tab   @tab X
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    @tab Used in some games from Bethesda Softworks.
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@item Brute Force & Ignorance   @tab   @tab X
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    @tab Used in the game Flash Traffic: City of Angels.
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@item Interplay C93             @tab   @tab X
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    @tab Used in the game Cyberia from Interplay.
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@item Delphine Software International CIN @tab   @tab X
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    @tab Multimedia format used by Delphine Software games.
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@item CRC testing format        @tab X @tab
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@item Creative Voice            @tab X @tab X
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    @tab Created for the Sound Blaster Pro.
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@item CRYO APC                  @tab   @tab X
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    @tab Audio format used in some games by CRYO Interactive Entertainment.
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@item D-Cinema audio            @tab X @tab X
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@item DV video                  @tab X @tab X
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@item DXA                       @tab   @tab X
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    @tab This format is used in the non-Windows version of the Feeble Files
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         game and different game cutscenes repacked for use with ScummVM.
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@item Electronic Arts cdata  @tab    @tab X
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@item Electronic Arts Multimedia  @tab    @tab X
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    @tab Used in various EA games; files have extensions like WVE and UV2.
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@item FFM (FFserver live feed)  @tab X @tab X
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@item Flash (SWF)               @tab X @tab X
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@item Flash 9 (AVM2)            @tab X @tab X
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    @tab Only embedded audio is decoded.
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@item FLI/FLC/FLX animation     @tab   @tab X
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    @tab .fli/.flc files
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@item Flash Video (FLV)         @tab   @tab X
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    @tab Macromedia Flash video files
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@item framecrc testing format   @tab X @tab
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@item FunCom ISS                @tab   @tab X
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    @tab Audio format used in various games from FunCom like The Longest Journey.
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@item GIF Animation             @tab X @tab
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@item GXF                       @tab X @tab X
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    @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley
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         playout servers.
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@item id Quake II CIN video     @tab   @tab X
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@item id RoQ                    @tab X @tab X
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    @tab Used in Quake III, Jedi Knight 2, other computer games.
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@item IFF                       @tab   @tab X
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    @tab Interchange File Format
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@item Interplay MVE             @tab   @tab X
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    @tab Format used in various Interplay computer games.
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@item LMLM4                     @tab   @tab X
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    @tab Used by Linux Media Labs MPEG-4 PCI boards
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@item Matroska                  @tab X @tab X
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@item Matroska audio            @tab X @tab
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@item MAXIS XA                  @tab   @tab X
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    @tab Used in Sim City 3000; file extension .xa.
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@item Monkey's Audio            @tab   @tab X
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@item Motion Pixels MVI         @tab   @tab X
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@item MOV/QuickTime/MP4         @tab X @tab X
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    @tab 3GP, 3GP2, PSP, iPod variants supported
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@item MP2                       @tab X @tab X
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@item MP3                       @tab X @tab X
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@item MPEG-1 System             @tab X @tab X
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    @tab muxed audio and video, VCD format supported
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@item MPEG-PS (program stream)  @tab X @tab X
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    @tab also known as @code{VOB} file, SVCD and DVD format supported
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@item MPEG-TS (transport stream) @tab X @tab X
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    @tab also known as DVB Transport Stream
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@item MPEG-4                    @tab X @tab X
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    @tab MPEG-4 is a variant of QuickTime.
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@item MIME multipart JPEG       @tab X @tab
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@item MSN TCP webcam            @tab   @tab X
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    @tab Used by MSN Messenger webcam streams.
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@item MTV                       @tab   @tab X
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@item Musepack                  @tab   @tab X
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@item Musepack SV8              @tab   @tab X
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@item Material eXchange Format (MXF) @tab X @tab X
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    @tab SMPTE 377M, used by D-Cinema, broadcast industry.
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@item Material eXchange Format (MXF), D-10 Mapping @tab X @tab X
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    @tab SMPTE 386M, D-10/IMX Mapping.
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@item NC camera feed            @tab   @tab X
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    @tab NC (AVIP NC4600) camera streams
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@item Nullsoft Streaming Video  @tab   @tab X
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@item NuppelVideo               @tab   @tab X
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@item NUT                       @tab X @tab X
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    @tab NUT Open Container Format
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@item Ogg                       @tab X @tab X
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@item TechnoTrend PVA           @tab   @tab X
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    @tab Used by TechnoTrend DVB PCI boards.
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@item raw ADTS (AAC)            @tab X @tab X
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@item raw AC-3                  @tab X @tab X
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@item raw Chinese AVS video     @tab   @tab X
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@item raw CRI ADX               @tab X @tab X
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@item raw Dirac                 @tab X @tab X
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@item raw DNxHD                 @tab X @tab X
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@item raw DTS                   @tab X @tab X
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@item raw E-AC-3                @tab X @tab X
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@item raw FLAC                  @tab X @tab X
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@item raw GSM                   @tab   @tab X
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@item raw H.261                 @tab X @tab X
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@item raw H.263                 @tab X @tab X
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@item raw H.264                 @tab X @tab X
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@item raw Ingenient MJPEG       @tab   @tab X
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@item raw MJPEG                 @tab X @tab X
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@item raw MLP                   @tab   @tab X
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@item raw MPEG                  @tab   @tab X
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@item raw MPEG-1                @tab   @tab X
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@item raw MPEG-2                @tab   @tab X
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@item raw MPEG-4                @tab X @tab X
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@item raw NULL                  @tab X @tab
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@item raw video                 @tab X @tab X
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@item raw id RoQ                @tab X @tab
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@item raw Shorten               @tab   @tab X
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@item raw VC-1                  @tab   @tab X
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@item raw PCM A-law             @tab X @tab X
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@item raw PCM mu-law            @tab X @tab X
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@item raw PCM signed 8 bit      @tab X @tab X
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@item raw PCM signed 16 bit big-endian  @tab X @tab X
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@item raw PCM signed 16 bit little-endian  @tab X @tab X
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@item raw PCM signed 24 bit big-endian  @tab X @tab X
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@item raw PCM signed 24 bit little-endian  @tab X @tab X
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@item raw PCM signed 32 bit big-endian  @tab X @tab X
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@item raw PCM signed 32 bit little-endian  @tab X @tab X
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@item raw PCM unsigned 8 bit    @tab X @tab X
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@item raw PCM unsigned 16 bit big-endian  @tab X @tab X
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@item raw PCM unsigned 16 bit little-endian  @tab X @tab X
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@item raw PCM unsigned 24 bit big-endian  @tab X @tab X
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@item raw PCM unsigned 24 bit little-endian  @tab X @tab X
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@item raw PCM unsigned 32 bit big-endian  @tab X @tab X
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@item raw PCM unsigned 32 bit little-endian  @tab X @tab X
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@item raw PCM floating-point 32 bit big-endian  @tab X @tab X
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@item raw PCM floating-point 32 bit little-endian  @tab X @tab X
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@item raw PCM floating-point 64 bit big-endian  @tab X @tab X
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@item raw PCM floating-point 64 bit little-endian  @tab X @tab X
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@item RDT                       @tab   @tab X
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@item REDCODE R3D               @tab   @tab X
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    @tab File format used by RED Digital cameras, contains JPEG 2000 frames and PCM audio.
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@item RealMedia                 @tab X @tab X
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@item Redirector                @tab   @tab X
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@item Renderware TeXture Dictionary @tab   @tab X
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@item RL2                       @tab   @tab X
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    @tab Audio and video format used in some games by Entertainment Software Partners.
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@item RPL/ARMovie               @tab   @tab X
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@item RTP                       @tab   @tab X
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@item RTSP                      @tab   @tab X
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@item SDP                       @tab   @tab X
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@item Sega FILM/CPK             @tab   @tab X
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    @tab Used in many Sega Saturn console games.
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@item Sierra SOL                @tab   @tab X
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    @tab .sol files used in Sierra Online games.
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@item Sierra VMD                @tab   @tab X
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    @tab Used in Sierra CD-ROM games.
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@item Smacker                   @tab   @tab X
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    @tab Multimedia format used by many games.
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@item Sony OpenMG (OMA)         @tab   @tab X
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    @tab Audio format used in Sony Sonic Stage and Sony Vegas.
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@item Sony PlayStation STR      @tab   @tab X
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@item SUN AU format             @tab X @tab X
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@item THP                       @tab   @tab X
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    @tab Used on the Nintendo GameCube.
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@item Tiertex Limited SEQ       @tab   @tab X
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    @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
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@item True Audio                @tab   @tab X
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@item VC-1 test bitstream       @tab X @tab X
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@item WAV                       @tab X @tab X
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@item WavPack                   @tab   @tab X
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@item Wing Commander III movie  @tab   @tab X
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    @tab Multimedia format used in Origin's Wing Commander III computer game.
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@item Westwood Studios audio    @tab   @tab X
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    @tab Multimedia format used in Westwood Studios games.
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@item Westwood Studios VQA      @tab   @tab X
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    @tab Multimedia format used in Westwood Studios games.
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@item YUV4MPEG pipe             @tab X @tab X
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@end multitable
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@code{X} means that encoding (resp. decoding) is supported.
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@section Image Formats
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FFmpeg can read and write images for each frame of a video sequence. The
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following image formats are supported:
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@multitable @columnfractions .4 .1 .1 .4
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@item Name @tab Encoding @tab Decoding @tab Comments
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@item .Y.U.V       @tab X @tab X
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    @tab one raw file per component
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@item animated GIF @tab X @tab X
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    @tab Only uncompressed GIFs are generated.
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@item BMP          @tab X @tab X
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    @tab Microsoft BMP image
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@item JPEG         @tab X @tab X
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    @tab Progressive JPEG is not supported.
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@item JPEG 2000    @tab   @tab E
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    @tab decoding supported through external library libopenjpeg
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@item JPEG-LS      @tab X @tab X
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@item LJPEG        @tab X @tab
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    @tab Lossless JPEG
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@item PAM          @tab X @tab X
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    @tab PAM is a PNM extension with alpha support.
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@item PBM          @tab X @tab X
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    @tab Portable BitMap image
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@item PCX          @tab   @tab X
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    @tab PC Paintbrush
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@item PGM          @tab X @tab X
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    @tab Portable GrayMap image
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@item PGMYUV       @tab X @tab X
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    @tab PGM with U and V components in YUV 4:2:0
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@item PNG          @tab X @tab X
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    @tab 2/4 bpp not supported yet
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@item PPM          @tab X @tab X
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    @tab Portable PixelMap image
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@item PTX          @tab   @tab X
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    @tab V.Flash PTX format
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@item SGI          @tab X @tab X
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    @tab SGI RGB image format
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@item Sun Rasterfile  @tab   @tab X
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    @tab Sun RAS image format
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@item TIFF         @tab X @tab X
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    @tab YUV, JPEG and some extension is not supported yet.
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@item Truevision Targa  @tab X @tab X
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    @tab Targa (.TGA) image format
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@end multitable
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@code{X} means that encoding (resp. decoding) is supported.
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@code{E} means that support is provided through an external library.
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@section Video Codecs
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@multitable @columnfractions .4 .1 .1 .4
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@item Name @tab Encoding @tab Decoding @tab Comments
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@item 4X Movie               @tab     @tab  X
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    @tab Used in certain computer games.
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@item 8SVX exponential       @tab     @tab  X
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@item 8SVX fibonacci         @tab     @tab  X
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@item American Laser Games MM  @tab    @tab X
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    @tab Used in games like Mad Dog McCree.
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@item AMV Video              @tab     @tab  X
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    @tab Used in Chinese MP3 players.
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@item Apple MJPEG-B          @tab     @tab  X
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@item Apple QuickDraw        @tab     @tab  X
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    @tab fourcc: qdrw
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@item Asus v1                @tab  X  @tab  X
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    @tab fourcc: ASV1
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@item Asus v2                @tab  X  @tab  X
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    @tab fourcc: ASV2
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@item ATI VCR1               @tab     @tab  X
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    @tab fourcc: VCR1
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@item ATI VCR2               @tab     @tab  X
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    @tab fourcc: VCR2
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@item Autodesk Animator Flic video  @tab     @tab  X
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@item Autodesk RLE           @tab     @tab  X
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    @tab fourcc: AASC
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@item AVS (Audio Video Standard) video  @tab     @tab  X
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    @tab Video encoding used by the Creature Shock game.
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@item Beam Software VB       @tab     @tab  X
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@item Bethesda VID video     @tab     @tab  X
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    @tab Used in some games from Bethesda Softworks.
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@item Brute Force & Ignorance   @tab   @tab X
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    @tab Used in the game Flash Traffic: City of Angels.
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@item C93 video              @tab     @tab  X
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    @tab Codec used in Cyberia game.
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@item CamStudio              @tab     @tab  X
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    @tab fourcc: CSCD
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@item Chinese AVS video      @tab     @tab  X
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    @tab AVS1-P2, JiZhun profile
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@item Delphine Software International CIN video  @tab     @tab  X
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    @tab Codec used in Delphine Software International games.
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@item Cinepak                @tab     @tab  X
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@item Cirrus Logic AccuPak   @tab     @tab  X
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    @tab fourcc: CLJR
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@item Creative YUV (CYUV)    @tab     @tab  X
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@item Dirac                  @tab  E  @tab  E
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    @tab supported through external libdirac/libschroedinger libraries
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@item DNxHD                  @tab   X @tab  X
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    @tab aka SMPTE VC3
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@item Duck TrueMotion 1.0   @tab     @tab  X
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    @tab fourcc: DUCK
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@item Duck TrueMotion 2.0    @tab     @tab  X
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    @tab fourcc: TM20
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@item DV (Digital Video)     @tab  X  @tab  X
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@item Feeble Files/ScummVM DXA  @tab     @tab  X
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    @tab Codec originally used in Feeble Files game.
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@item Electronic Arts CMV video  @tab     @tab  X
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    @tab Used in NHL 95 game.
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@item Electronic Arts TGV video  @tab     @tab  X
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@item Electronic Arts TGQ video  @tab     @tab  X
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@item Electronic Arts TQI video  @tab     @tab  X
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@item Escape 124             @tab     @tab  X
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@item FFmpeg codec #1        @tab  X  @tab  X
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    @tab experimental lossless codec (fourcc: FFV1)
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@item Flash Screen Video v1  @tab  X  @tab  X
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    @tab fourcc: FSV1
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@item Flash Video (FLV)      @tab  X  @tab  X
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    @tab Sorenson H.263 used in Flash
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@item Fraps                  @tab     @tab  X
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@item H.261                  @tab  X  @tab  X
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@item H.263 / H.263-1996     @tab  X  @tab  X
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@item H.263+ / H.263-1998 / H.263 version 2  @tab  X  @tab  X
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@item H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10  @tab  E  @tab  X
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    @tab encoding supported through external library libx264
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@item H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (VDPAU acceleration)  @tab  E  @tab  X
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@item HuffYUV                @tab  X  @tab  X
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@item HuffYUV FFmpeg variant @tab  X  @tab  X
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@item IBM Ultimotion         @tab     @tab  X
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    @tab fourcc: ULTI
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@item id Cinematic video     @tab     @tab  X
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    @tab Used in Quake II.
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@item id RoQ video           @tab  X  @tab  X
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    @tab Used in Quake III, Jedi Knight 2, other computer games.
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@item Intel H.263            @tab     @tab  X
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@item Intel Indeo 2          @tab     @tab  X
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@item Intel Indeo 3          @tab     @tab  X
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@item Interplay C93          @tab     @tab  X
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    @tab Used in the game Cyberia from Interplay.
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@item Interplay MVE video    @tab     @tab  X
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    @tab Used in Interplay .MVE files.
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@item Karl Morton's video codec  @tab     @tab  X
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    @tab Codec used in Worms games.
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@item LCL (LossLess Codec Library) MSZH  @tab     @tab  X
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@item LCL (LossLess Codec Library) ZLIB  @tab  E  @tab  E
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@item LOCO                   @tab     @tab  X
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@item lossless MJPEG         @tab  X  @tab  X
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@item Microsoft RLE          @tab     @tab  X
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@item Microsoft Video 1      @tab     @tab  X
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@item Mimic                  @tab     @tab  X
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    @tab Used in MSN Messenger Webcam streams.
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@item Miro VideoXL           @tab     @tab  X
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    @tab fourcc: VIXL
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@item MJPEG (Motion JPEG)    @tab  X  @tab  X
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@item Motion Pixels video    @tab     @tab  X
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@item MPEG-1 video           @tab  X  @tab  X
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@item MPEG-1/2 video XvMC (X-Video Motion Compensation)  @tab     @tab  X
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@item MPEG-1/2 video (VDPAU acceleration)  @tab     @tab  X
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@item MPEG-2 video           @tab  X  @tab  X
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@item MPEG-4 part 2          @tab  X  @tab  X
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    @ libxvidcore can be used alternatively for encoding.
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@item MPEG-4 part 2 Microsoft variant version 1  @tab  X  @tab  X
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@item MPEG-4 part 2 Microsoft variant version 2  @tab  X  @tab  X
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@item MPEG-4 part 2 Microsoft variant version 3  @tab  X  @tab  X
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@item Nintendo Gamecube THP video  @tab     @tab  X
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@item NuppelVideo/RTjpeg     @tab     @tab  X
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    @tab Video encoding used in NuppelVideo files.
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@item On2 VP3                @tab     @tab  X
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    @tab still experimental
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@item On2 VP5                @tab     @tab  X
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    @tab fourcc: VP50
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@item On2 VP6                @tab     @tab  X
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    @tab fourcc: VP60,VP61,VP62
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@item planar RGB             @tab     @tab  X
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    @tab fourcc: 8BPS
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@item Q-team QPEG            @tab     @tab  X
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    @tab fourccs: QPEG, Q1.0, Q1.1
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@item QuickTime 8BPS video   @tab     @tab  X
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@item QuickTime Animation (RLE) video  @tab  X  @tab  X
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    @tab fourcc: 'rle '
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@item QuickTime Graphics (SMC)  @tab     @tab  X
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    @tab fourcc: 'smc '
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@item QuickTime video (RPZA) @tab     @tab  X
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    @tab fourcc: rpza
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@item Raw Video              @tab  X  @tab  X
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@item RealVideo 1.0          @tab  X  @tab  X
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@item RealVideo 2.0          @tab  X  @tab  X
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@item RealVideo 3.0          @tab     @tab  X
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    @tab still far from ideal
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@item RealVideo 4.0          @tab     @tab  X
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@item Renderware TXD (TeXture Dictionary)  @tab     @tab  X
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    @tab Texture dictionaries used by the Renderware Engine.
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@item RL2 video              @tab     @tab  X
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    @tab used in some games by Entertainment Software Partners
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@item Sierra VMD video       @tab     @tab  X
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    @tab Used in Sierra VMD files.
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@item Smacker video          @tab     @tab  X
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    @tab Video encoding used in Smacker.
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@item SMPTE VC-1             @tab     @tab  X
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@item Snow                   @tab  X  @tab  X
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    @tab experimental wavelet codec (fourcc: SNOW)
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@item Sony PlayStation MDEC (Motion DECoder)  @tab     @tab  X
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@item Sorenson Vector Quantizer 1  @tab  X  @tab  X
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    @tab fourcc: SVQ1
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@item Sorenson Vector Quantizer 3  @tab     @tab  X
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    @tab fourcc: SVQ3
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@item Sunplus JPEG (SP5X)    @tab     @tab  X
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    @tab fourcc: SP5X
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@item TechSmith Screen Capture Codec  @tab     @tab  X
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    @tab fourcc: TSCC
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@item Theora                 @tab  E  @tab  X
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    @tab encoding supported through external library libtheora
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@item Tiertex Limited SEQ video  @tab     @tab  X
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    @tab Codec used in DOS CD-ROM FlashBack game.
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@item VMware Screen Codec / VMware Video  @tab     @tab  X
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    @tab Codec used in videos captured by VMware.
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@item Westwood Studios VQA (Vector Quantized Animation) video  @tab     @tab  X
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@item Windows Media Video 7  @tab  X  @tab  X
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@item Windows Media Video 8  @tab  X  @tab  X
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@item Windows Media Video 9  @tab     @tab  X
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    @tab not completely working
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@item Wing Commander III / Xan  @tab     @tab  X
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    @tab Used in Wing Commander III .MVE files.
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@item Winnov WNV1            @tab     @tab  X
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@item WMV7                   @tab  X  @tab  X
451
@item YAMAHA SMAF            @tab  X  @tab  X
452
@item ZLIB                   @tab  X  @tab  X
453
    @tab part of LCL, encoder experimental
454
@item Zip Motion Blocks Video  @tab   X @tab  X
455
    @tab Encoder works only in PAL8.
456
@end multitable
457

    
458
@code{X} means that encoding (resp. decoding) is supported.
459

    
460
@code{E} means that support is provided through an external library.
461

    
462
@section Audio Codecs
463

    
464
@multitable @columnfractions .4 .1 .1 .4
465
@item Name @tab Encoding @tab Decoding @tab Comments
466
@item 8SVX audio             @tab     @tab  X
467
@item AAC                    @tab  E  @tab  X
468
    @tab encoding supported through external library libfaac
469
@item AC-3                   @tab IX  @tab  X
470
@item ADPCM 4X Movie         @tab     @tab  X
471
@item ADPCM CDROM XA         @tab     @tab  X
472
@item ADPCM Creative Technology @tab     @tab  X
473
    @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
474
@item ADPCM Electronic Arts  @tab     @tab  X
475
    @tab Used in various EA titles.
476
@item ADPCM Electronic Arts Maxis CDROM XS  @tab     @tab  X
477
    @tab Used in Sim City 3000.
478
@item ADPCM Electronic Arts R1  @tab     @tab  X
479
@item ADPCM Electronic Arts R2  @tab     @tab  X
480
@item ADPCM Electronic Arts R3  @tab     @tab  X
481
@item ADPCM Electronic Arts XAS @tab     @tab  X
482
@item ADPCM G.726            @tab  X  @tab  X
483
@item ADPCM IMA AMV          @tab     @tab  X
484
    @tab Used in AMV files
485
@item ADPCM IMA Electronic Arts EACS  @tab     @tab  X
486
@item ADPCM IMA Electronic Arts SEAD  @tab     @tab  X
487
@item ADPCM IMA Funcom       @tab     @tab  X
488
@item ADPCM IMA QuickTime    @tab  X  @tab  X
489
@item ADPCM IMA Loki SDL MJPEG  @tab     @tab  X
490
@item ADPCM IMA WAV          @tab  X  @tab  X
491
@item ADPCM IMA Westwood     @tab     @tab  X
492
@item ADPCM ISS IMA          @tab     @tab  X
493
    @tab Used in FunCom games.
494
@item ADPCM IMA Duck DK3     @tab     @tab  X
495
    @tab Used in some Sega Saturn console games.
496
@item ADPCM IMA Duck DK4     @tab     @tab  X
497
    @tab Used in some Sega Saturn console games.
498
@item ADPCM Microsoft        @tab  X  @tab  X
499
@item ADPCM MS IMA           @tab  X  @tab  X
500
@item ADPCM Nintendo Gamecube THP  @tab     @tab  X
501
@item ADPCM QT IMA           @tab  X  @tab  X
502
@item ADPCM SEGA CRI ADX     @tab  X  @tab  X
503
    @tab Used in Sega Dreamcast games.
504
@item ADPCM Shockwave Flash  @tab  X  @tab  X
505
@item ADPCM SMJPEG IMA       @tab     @tab  X
506
    @tab Used in certain Loki game ports.
507
@item ADPCM Sound Blaster Pro 2-bit  @tab     @tab  X
508
@item ADPCM Sound Blaster Pro 2.6-bit  @tab     @tab  X
509
@item ADPCM Sound Blaster Pro 4-bit  @tab     @tab  X
510
@item ADPCM Westwood Studios IMA @tab     @tab  X
511
    @tab Used in Westwood Studios games like Command and Conquer.
512
@item ADPCM Yamaha           @tab  X  @tab  X
513
@item AMR-NB                 @tab  E  @tab  E
514
    @tab supported through external library libamrnb
515
@item AMR-WB                 @tab  E  @tab  E
516
    @tab supported through external library libamrwb
517
@item Apple lossless audio   @tab  X  @tab  X
518
    @tab QuickTime fourcc 'alac'
519
@item Atrac 3                @tab     @tab  X
520
@item Delphine Software International CIN audio  @tab     @tab  X
521
    @tab Codec used in Delphine Software International games.
522
@item COOK                   @tab     @tab  X
523
    @tab All versions except 5.1 are supported.
524
@item DCA (DTS Coherent Acoustics)  @tab     @tab  X
525
@item DPCM id RoQ            @tab  X  @tab  X
526
    @tab Used in Quake III, Jedi Knight 2, other computer games.
527
@item DPCM Interplay         @tab     @tab  X
528
    @tab Used in various Interplay computer games.
529
@item DPCM Sierra Online     @tab     @tab  X
530
    @tab Used in Sierra Online game audio files.
531
@item DPCM Sol               @tab     @tab  X
532
@item DPCM Xan               @tab     @tab  X
533
@item DSP Group TrueSpeech   @tab     @tab  X
534
@item DV audio               @tab     @tab  X
535
@item Enhanced AC-3          @tab     @tab  X
536
@item FLAC (Free Lossless Audio Codec)  @tab  X  @tab  IX
537
@item G.729                  @tab     @tab  X
538
@item GSM                    @tab  E  @tab  E
539
    @tab supported through external library libgsm
540
@item GSM Microsoft variant  @tab  E  @tab  E
541
    @tab supported through external library libgsm
542
@item IMC (Intel Music Coder)  @tab     @tab  X
543
@item MACE (Macintosh Audio Compression/Expansion) 3:1  @tab     @tab  X
544
@item MACE (Macintosh Audio Compression/Expansion) 6:1  @tab     @tab  X
545
@item MLP(Meridian Lossless Packing)/TrueHD  @tab     @tab  X
546
    @tab Used in DVD-Audio and Blu-Ray discs.
547
@item Monkey's Audio         @tab     @tab  X
548
    @tab Only versions 3.97-3.99 are supported.
549
@item MP1 (MPEG audio layer 1)  @tab     @tab IX
550
@item MP2 (MPEG audio layer 2)  @tab IX  @tab IX
551
@item MP3 (MPEG audio layer 3)  @tab  E  @tab IX
552
    @tab encoding supported through external library LAME, ADU MP3 and MP3onMP4 also supported
553
@item Musepack SV7           @tab     @tab  X
554
@item Musepack SV8           @tab     @tab  X
555
@item Nellymoser Asao        @tab  X  @tab  X
556
@item PCM A-law              @tab  X  @tab  X
557
@item PCM mu-law             @tab  X  @tab  X
558
@item PCM 16-bit little-endian planar  @tab     @tab  X
559
@item PCM 32-bit floating point big-endian  @tab  X  @tab  X
560
@item PCM 32-bit floating point little-endian  @tab  X  @tab  X
561
@item PCM 64-bit floating point big-endian  @tab  X  @tab  X
562
@item PCM 64-bit floating point little-endian  @tab  X  @tab  X
563
@item PCM D-Cinema audio signed 24-bit   @tab  X  @tab  X
564
@item PCM signed 8-bit       @tab  X  @tab  X
565
@item PCM signed 16-bit big-endian  @tab  X  @tab  X
566
@item PCM signed 16-bit little-endian  @tab  X  @tab  X
567
@item PCM signed 24-bit big-endian  @tab  X  @tab  X
568
@item PCM signed 24-bit little-endian  @tab  X  @tab  X
569
@item PCM signed 32-bit big-endian  @tab  X  @tab  X
570
@item PCM signed 32-bit little-endian  @tab  X  @tab  X
571
@item PCM unsigned 8-bit     @tab  X  @tab  X
572
@item PCM unsigned 16-bit big-endian  @tab  X  @tab  X
573
@item PCM unsigned 16-bit little-endian  @tab  X  @tab  X
574
@item PCM unsigned 24-bit big-endian  @tab  X  @tab  X
575
@item PCM unsigned 24-bit little-endian  @tab  X  @tab  X
576
@item PCM unsigned 32-bit big-endian  @tab  X  @tab  X
577
@item PCM unsigned 32-bit little-endian  @tab  X  @tab  X
578
@item PCM Zork               @tab  X  @tab  X
579
@item QCELP / PureVoice      @tab     @tab  X
580
@item QDesign Music Codec 2  @tab     @tab  X
581
    @tab There are still some distortions.
582
@item RealAudio 1.0 (14.4K)  @tab     @tab  X
583
    @tab Real 14400 bit/s codec
584
@item RealAudio 2.0 (28.8K)  @tab     @tab  X
585
    @tab Real 28800 bit/s codec
586
@item RealAudio 3.0 (dnet)   @tab IX  @tab  X
587
    @tab Real low bitrate AC-3 codec
588
@item Shorten                @tab     @tab  X
589
@item Sierra VMD audio       @tab     @tab  X
590
    @tab Used in Sierra VMD files.
591
@item Smacker audio          @tab     @tab  X
592
@item Sonic                  @tab  X  @tab  X
593
    @tab experimental codec
594
@item Sonic lossless         @tab  X  @tab  X
595
    @tab experimental codec
596
@item Speex                  @tab     @tab  E
597
    @tab supported through external library libspeex
598
@item True Audio (TTA)       @tab     @tab  X
599
@item Vorbis                 @tab  E  @tab  X
600
    @ A native but very primitive encoder exists.
601
@item WavPack                @tab     @tab  X
602
@item Westwood Audio (SND1)  @tab     @tab  X
603
@item Windows Media Audio 1  @tab  X  @tab  X
604
@item Windows Media Audio 2  @tab  X  @tab  X
605
    @tab Used in Origin's Wing Commander IV AVI files.
606
@end multitable
607

    
608
@code{X} means that encoding (resp. decoding) is supported.
609

    
610
@code{E} means that support is provided through an external library.
611

    
612
@code{I} means that an integer-only version is available, too (ensures high
613
performance on systems without hardware floating point support).
614

    
615
@section Subtitle Formats
616

    
617
@multitable @columnfractions .4 .1 .1 .1 .1 .1
618
@item Name @tab Muxing @tab Demuxing @tab Encoding @tab Decoding
619
@item SSA/ASS      @tab X @tab X
620
@item DVB          @tab X @tab X @tab X @tab X
621
@item DVD          @tab X @tab X @tab X @tab X
622
@item XSUB         @tab   @tab   @tab   @tab X
623
@end multitable
624

    
625
@code{X} means that the feature is supported.
626

    
627
@section Network Protocols
628

    
629
@multitable @columnfractions .4 .1 .1 .1 .1 .1
630
@item Name         @tab Support
631
@item file         @tab X
632
@item Gopher       @tab X
633
@item HTTP         @tab X
634
@item pipe         @tab X
635
@item RTP          @tab X
636
@item TCP          @tab X
637
@item UDP          @tab X
638
@end multitable
639

    
640
@code{X} means that the protocol is supported.
641

    
642

    
643
@chapter Platform Specific information
644

    
645
@section BSD
646

    
647
BSD make will not build FFmpeg, you need to install and use GNU Make
648
(@file{gmake}).
649

    
650
@section Windows
651

    
652
To get help and instructions for building FFmpeg under Windows, check out
653
the FFmpeg Windows Help Forum at
654
@url{http://ffmpeg.arrozcru.org/}.
655

    
656
@subsection Native Windows compilation
657

    
658
FFmpeg can be built to run natively on Windows using the MinGW tools. Install
659
the latest versions of MSYS and MinGW from @url{http://www.mingw.org/}.
660
You can find detailed installation
661
instructions in the download section and the FAQ.
662

    
663
FFmpeg does not build out-of-the-box with the packages the automated MinGW
664
installer provides. It also requires coreutils to be installed and many other
665
packages updated to the latest version. The minimum version for some packages
666
are listed below:
667

    
668
@itemize
669
@item bash 3.1
670
@item msys-make 3.81-2 (note: not mingw32-make)
671
@item w32api 3.13
672
@item mingw-runtime 3.15
673
@end itemize
674

    
675
You will also need to pass @code{-fno-common} to the compiler to work around
676
a GCC bug (see @url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216}).
677

    
678
Within the MSYS shell, configure and make with:
679

    
680
@example
681
./configure --enable-memalign-hack --extra-cflags=-fno-common
682
make
683
make install
684
@end example
685

    
686
This will install @file{ffmpeg.exe} along with many other development files
687
to @file{/usr/local}. You may specify another install path using the
688
@code{--prefix} option in @file{configure}.
689

    
690
Notes:
691

    
692
@itemize
693

    
694
@item In order to compile vhooks, you must have a POSIX-compliant libdl in
695
your MinGW system. Get dlfcn-win32 from
696
@url{http://code.google.com/p/dlfcn-win32}.
697

    
698
@item In order to compile FFplay, you must have the MinGW development library
699
of SDL. Get it from @url{http://www.libsdl.org}.
700
Edit the @file{bin/sdl-config} script so that it points to the correct prefix
701
where SDL was installed. Verify that @file{sdl-config} can be launched from
702
the MSYS command line.
703

    
704
@item By using @code{./configure --enable-shared} when configuring FFmpeg,
705
you can build libavutil, libavcodec and libavformat as DLLs.
706

    
707
@end itemize
708

    
709
@subsection Microsoft Visual C++ compatibility
710

    
711
As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
712
want to use the libav* libraries in your own applications, you can still
713
compile those applications using MSVC++. But the libav* libraries you link
714
to @emph{must} be built with MinGW. However, you will not be able to debug
715
inside the libav* libraries, since MSVC++ does not recognize the debug
716
symbols generated by GCC.
717
We strongly recommend you to move over from MSVC++ to MinGW tools.
718

    
719
This description of how to use the FFmpeg libraries with MSVC++ is based on
720
Microsoft Visual C++ 2005 Express Edition. If you have a different version,
721
you might have to modify the procedures slightly.
722

    
723
@subsubsection Using static libraries
724

    
725
Assuming you have just built and installed FFmpeg in @file{/usr/local}.
726

    
727
@enumerate
728

    
729
@item Create a new console application ("File / New / Project") and then
730
select "Win32 Console Application". On the appropriate page of the
731
Application Wizard, uncheck the "Precompiled headers" option.
732

    
733
@item Write the source code for your application, or, for testing, just
734
copy the code from an existing sample application into the source file
735
that MSVC++ has already created for you. For example, you can copy
736
@file{output_example.c} from the FFmpeg distribution.
737

    
738
@item Open the "Project / Properties" dialog box. In the "Configuration"
739
combo box, select "All Configurations" so that the changes you make will
740
affect both debug and release builds. In the tree view on the left hand
741
side, select "C/C++ / General", then edit the "Additional Include
742
Directories" setting to contain the path where the FFmpeg includes were
743
installed (i.e. @file{c:\msys\1.0\local\include}).
744
Do not add MinGW's include directory here, or the include files will
745
conflict with MSVC's.
746

    
747
@item Still in the "Project / Properties" dialog box, select
748
"Linker / General" from the tree view and edit the
749
"Additional Library Directories" setting to contain the @file{lib}
750
directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
751
the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
752
and the directory where MinGW's GCC libs are installed
753
(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
754
"Linker / Input" from the tree view, and add the files @file{libavformat.a},
755
@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
756
@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
757
to the end of "Additional Dependencies".
758

    
759
@item Now, select "C/C++ / Code Generation" from the tree view. Select
760
"Debug" in the "Configuration" combo box. Make sure that "Runtime
761
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
762
the "Configuration" combo box and make sure that "Runtime Library" is
763
set to "Multi-threaded DLL".
764

    
765
@item Click "OK" to close the "Project / Properties" dialog box.
766

    
767
@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
768
Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
769
and install it in MSVC++'s include directory
770
(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
771

    
772
@item MSVC++ also does not understand the @code{inline} keyword used by
773
FFmpeg, so you must add this line before @code{#include}ing libav*:
774
@example
775
#define inline _inline
776
@end example
777

    
778
@item Build your application, everything should work.
779

    
780
@end enumerate
781

    
782
@subsubsection Using shared libraries
783

    
784
This is how to create DLL and LIB files that are compatible with MSVC++:
785

    
786
@enumerate
787

    
788
@item Add a call to @file{vcvars32.bat} (which sets up the environment
789
variables for the Visual C++ tools) as the first line of @file{msys.bat}.
790
The standard location for @file{vcvars32.bat} is
791
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
792
and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
793
If this corresponds to your setup, add the following line as the first line
794
of @file{msys.bat}:
795

    
796
@example
797
call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
798
@end example
799

    
800
Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
801
and run @file{c:\msys\1.0\msys.bat} from there.
802

    
803
@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
804
from @file{Microsoft (R) Library Manager}, this means your environment
805
variables are set up correctly, the @file{Microsoft (R) Library Manager}
806
is on the path and will be used by FFmpeg to create
807
MSVC++-compatible import libraries.
808

    
809
@item Build FFmpeg with
810

    
811
@example
812
./configure --enable-shared --enable-memalign-hack
813
make
814
make install
815
@end example
816

    
817
Your install path (@file{/usr/local/} by default) should now have the
818
necessary DLL and LIB files under the @file{bin} directory.
819

    
820
@end enumerate
821

    
822
To use those files with MSVC++, do the same as you would do with
823
the static libraries, as described above. But in Step 4,
824
you should only need to add the directory where the LIB files are installed
825
(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
826
installed in the @file{bin} directory. And instead of adding @file{libxx.a}
827
files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
828
@file{avutil.lib}. There should be no need for @file{libmingwex.a},
829
@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
830
statically linked into the DLLs. The @file{bin} directory contains a bunch
831
of DLL files, but the ones that are actually used to run your application
832
are the ones with a major version number in their filenames
833
(i.e. @file{avcodec-51.dll}).
834

    
835
@subsection Cross compilation for Windows with Linux
836

    
837
You must use the MinGW cross compilation tools available at
838
@url{http://www.mingw.org/}.
839

    
840
Then configure FFmpeg with the following options:
841
@example
842
./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
843
@end example
844
(you can change the cross-prefix according to the prefix chosen for the
845
MinGW tools).
846

    
847
Then you can easily test FFmpeg with Wine
848
(@url{http://www.winehq.com/}).
849

    
850
@subsection Compilation under Cygwin
851

    
852
The main issue with the 1.5.x Cygwin versions is that newlib, its C library,
853
does not contain llrint().  You need to upgrade to the unstable 1.7.x versions,
854
or leverage the implementation in MinGW (as explained below).
855

    
856
Just install your Cygwin with all the "Base" packages, plus the
857
following "Devel" ones:
858
@example
859
binutils, gcc-core, make, subversion, mingw-runtime, diffutils
860
@end example
861

    
862
The experimental gcc4 package is still buggy, hence please
863
use the official gcc 3.4.4 or a 4.2.x compiled from source by yourself.
864

    
865
Install the current binutils-20080624-2 as they work fine (the old
866
binutils-20060709-1 proved buggy on shared builds).
867

    
868
Then create a small library that just contains llrint():
869

    
870
@example
871
ar x /usr/lib/mingw/libmingwex.a llrint.o
872
ar cq /usr/local/lib/libllrint.a llrint.o
873
@end example
874

    
875
Then run
876

    
877
@example
878
./configure --enable-static --disable-shared  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
879
@end example
880

    
881
to make a static build or
882

    
883
@example
884
./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
885
@end example
886

    
887
to build shared libraries.
888

    
889
If you want to build FFmpeg with additional libraries, download Cygwin
890
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository:
891
@example
892
libogg-devel, libvorbis-devel
893
@end example
894

    
895
These library packages are only available from Cygwin Ports
896
(@url{http://sourceware.org/cygwinports/}) :
897

    
898
@example
899
yasm, libSDL-devel, libdirac-devel, libfaac-devel, libfaad-devel, libgsm-devel,
900
libmp3lame-devel, libschroedinger1.0-devel, speex-devel, libtheora-devel,
901
libxvidcore-devel
902
@end example
903

    
904
The recommendation for libnut and x264 is to build them from source by
905
yourself, as they evolve too quickly for Cygwin Ports to be up to date.
906

    
907
Cygwin 1.7.x has IPv6 support. You can add IPv6 to Cygwin 1.5.x by means
908
of the @code{libgetaddrinfo-devel} package, available at Cygwin Ports.
909

    
910
@subsection Crosscompilation for Windows under Cygwin
911

    
912
With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
913

    
914
Just install your Cygwin as explained before, plus these additional
915
"Devel" packages:
916
@example
917
gcc-mingw-core, mingw-runtime, mingw-zlib
918
@end example
919

    
920
and add some special flags to your configure invocation.
921

    
922
For a static build run
923
@example
924
./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
925
@end example
926

    
927
and for a build with shared libraries
928
@example
929
./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
930
@end example
931

    
932
@section BeOS
933

    
934
BeOS support is broken in mysterious ways.
935

    
936
@section OS/2
937

    
938
For information about compiling FFmpeg on OS/2 see
939
@url{http://www.edm2.com/index.php/FFmpeg}.
940

    
941
@chapter Developers Guide
942

    
943
@section API
944
@itemize @bullet
945
@item libavcodec is the library containing the codecs (both encoding and
946
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
947

    
948
@item libavformat is the library containing the file format handling (mux and
949
demux code for several formats). Look at @file{ffplay.c} to use it in a
950
player. See @file{output_example.c} to use it to generate audio or video
951
streams.
952

    
953
@end itemize
954

    
955
@section Integrating libavcodec or libavformat in your program
956

    
957
You can integrate all the source code of the libraries to link them
958
statically to avoid any version problem. All you need is to provide a
959
'config.mak' and a 'config.h' in the parent directory. See the defines
960
generated by ./configure to understand what is needed.
961

    
962
You can use libavcodec or libavformat in your commercial program, but
963
@emph{any patch you make must be published}. The best way to proceed is
964
to send your patches to the FFmpeg mailing list.
965

    
966
@node Coding Rules
967
@section Coding Rules
968

    
969
FFmpeg is programmed in the ISO C90 language with a few additional
970
features from ISO C99, namely:
971
@itemize @bullet
972
@item
973
the @samp{inline} keyword;
974
@item
975
@samp{//} comments;
976
@item
977
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
978
@item
979
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
980
@end itemize
981

    
982
These features are supported by all compilers we care about, so we will not
983
accept patches to remove their use unless they absolutely do not impair
984
clarity and performance.
985

    
986
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
987
compiles with several other compilers, such as the Compaq ccc compiler
988
or Sun Studio 9, and we would like to keep it that way unless it would
989
be exceedingly involved. To ensure compatibility, please do not use any
990
additional C99 features or GCC extensions. Especially watch out for:
991
@itemize @bullet
992
@item
993
mixing statements and declarations;
994
@item
995
@samp{long long} (use @samp{int64_t} instead);
996
@item
997
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
998
@item
999
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1000
@end itemize
1001

    
1002
Indent size is 4.
1003
The presentation is the one specified by 'indent -i4 -kr -nut'.
1004
The TAB character is forbidden outside of Makefiles as is any
1005
form of trailing whitespace. Commits containing either will be
1006
rejected by the Subversion repository.
1007

    
1008
The main priority in FFmpeg is simplicity and small code size in order to
1009
minimize the bug count.
1010

    
1011
Comments: Use the JavaDoc/Doxygen
1012
format (see examples below) so that code documentation
1013
can be generated automatically. All nontrivial functions should have a comment
1014
above them explaining what the function does, even if it is just one sentence.
1015
All structures and their member variables should be documented, too.
1016
@example
1017
/**
1018
 * @@file mpeg.c
1019
 * MPEG codec.
1020
 * @@author ...
1021
 */
1022

    
1023
/**
1024
 * Summary sentence.
1025
 * more text ...
1026
 * ...
1027
 */
1028
typedef struct Foobar@{
1029
    int var1; /**< var1 description */
1030
    int var2; ///< var2 description
1031
    /** var3 description */
1032
    int var3;
1033
@} Foobar;
1034

    
1035
/**
1036
 * Summary sentence.
1037
 * more text ...
1038
 * ...
1039
 * @@param my_parameter description of my_parameter
1040
 * @@return return value description
1041
 */
1042
int myfunc(int my_parameter)
1043
...
1044
@end example
1045

    
1046
fprintf and printf are forbidden in libavformat and libavcodec,
1047
please use av_log() instead.
1048

    
1049
Casts should be used only when necessary. Unneeded parentheses
1050
should also be avoided if they don't make the code easier to understand.
1051

    
1052
@section Development Policy
1053

    
1054
@enumerate
1055
@item
1056
   Contributions should be licensed under the LGPL 2.1, including an
1057
   "or any later version" clause, or the MIT license.  GPL 2 including
1058
   an "or any later version" clause is also acceptable, but LGPL is
1059
   preferred.
1060
@item
1061
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
1062
   enabled code which breaks compilation or compiles but does not work or
1063
   breaks the regression tests)
1064
   You can commit unfinished stuff (for testing etc), but it must be disabled
1065
   (#ifdef etc) by default so it does not interfere with other developers'
1066
   work.
1067
@item
1068
   You do not have to over-test things. If it works for you, and you think it
1069
   should work for others, then commit. If your code has problems
1070
   (portability, triggers compiler bugs, unusual environment etc) they will be
1071
   reported and eventually fixed.
1072
@item
1073
   Do not commit unrelated changes together, split them into self-contained
1074
   pieces. Also do not forget that if part B depends on part A, but A does not
1075
   depend on B, then A can and should be committed first and separate from B.
1076
   Keeping changes well split into self-contained parts makes reviewing and
1077
   understanding them on the commit log mailing list easier. This also helps
1078
   in case of debugging later on.
1079
   Also if you have doubts about splitting or not splitting, do not hesitate to
1080
   ask/discuss it on the developer mailing list.
1081
@item
1082
   Do not change behavior of the program (renaming options etc) without
1083
   first discussing it on the ffmpeg-devel mailing list. Do not remove
1084
   functionality from the code. Just improve!
1085

    
1086
   Note: Redundant code can be removed.
1087
@item
1088
   Do not commit changes to the build system (Makefiles, configure script)
1089
   which change behavior, defaults etc, without asking first. The same
1090
   applies to compiler warning fixes, trivial looking fixes and to code
1091
   maintained by other developers. We usually have a reason for doing things
1092
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
1093
   list, and if the code maintainers say OK, you may commit. This does not
1094
   apply to files you wrote and/or maintain.
1095
@item
1096
   We refuse source indentation and other cosmetic changes if they are mixed
1097
   with functional changes, such commits will be rejected and removed. Every
1098
   developer has his own indentation style, you should not change it. Of course
1099
   if you (re)write something, you can use your own style, even though we would
1100
   prefer if the indentation throughout FFmpeg was consistent (Many projects
1101
   force a given indentation style - we do not.). If you really need to make
1102
   indentation changes (try to avoid this), separate them strictly from real
1103
   changes.
1104

    
1105
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1106
   then either do NOT change the indentation of the inner part within (do not
1107
   move it to the right)! or do so in a separate commit
1108
@item
1109
   Always fill out the commit log message. Describe in a few lines what you
1110
   changed and why. You can refer to mailing list postings if you fix a
1111
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1112
@item
1113
   If you apply a patch by someone else, include the name and email address in
1114
   the log message. Since the ffmpeg-cvslog mailing list is publicly
1115
   archived you should add some SPAM protection to the email address. Send an
1116
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
1117
   you applied the patch.
1118
@item
1119
   When applying patches that have been discussed (at length) on the mailing
1120
   list, reference the thread in the log message.
1121
@item
1122
    Do NOT commit to code actively maintained by others without permission.
1123
    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
1124
    timeframe (12h for build failures and security fixes, 3 days small changes,
1125
    1 week for big patches) then commit your patch if you think it is OK.
1126
    Also note, the maintainer can simply ask for more time to review!
1127
@item
1128
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1129
    are sent there and reviewed by all the other developers. Bugs and possible
1130
    improvements or general questions regarding commits are discussed there. We
1131
    expect you to react if problems with your code are uncovered.
1132
@item
1133
    Update the documentation if you change behavior or add features. If you are
1134
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1135
    maintainer(s) will review and commit your stuff.
1136
@item
1137
    Try to keep important discussions and requests (also) on the public
1138
    developer mailing list, so that all developers can benefit from them.
1139
@item
1140
    Never write to unallocated memory, never write over the end of arrays,
1141
    always check values read from some untrusted source before using them
1142
    as array index or other risky things.
1143
@item
1144
    Remember to check if you need to bump versions for the specific libav
1145
    parts (libavutil, libavcodec, libavformat) you are changing. You need
1146
    to change the version integer.
1147
    Incrementing the first component means no backward compatibility to
1148
    previous versions (e.g. removal of a function from the public API).
1149
    Incrementing the second component means backward compatible change
1150
    (e.g. addition of a function to the public API or extension of an
1151
    existing data structure).
1152
    Incrementing the third component means a noteworthy binary compatible
1153
    change (e.g. encoder bug fix that matters for the decoder).
1154
@item
1155
    Compiler warnings indicate potential bugs or code with bad style. If a type of
1156
    warning always points to correct and clean code, that warning should
1157
    be disabled, not the code changed.
1158
    Thus the remaining warnings can either be bugs or correct code.
1159
    If it is a bug, the bug has to be fixed. If it is not, the code should
1160
    be changed to not generate a warning unless that causes a slowdown
1161
    or obfuscates the code.
1162
@item
1163
    If you add a new file, give it a proper license header. Do not copy and
1164
    paste it from a random place, use an existing file as template.
1165
@end enumerate
1166

    
1167
We think our rules are not too hard. If you have comments, contact us.
1168

    
1169
Note, these rules are mostly borrowed from the MPlayer project.
1170

    
1171
@section Submitting patches
1172

    
1173
First, (@pxref{Coding Rules}) above if you did not yet.
1174

    
1175
When you submit your patch, try to send a unified diff (diff '-up'
1176
option). We cannot read other diffs :-)
1177

    
1178
Also please do not submit a patch which contains several unrelated changes.
1179
Split it into separate, self-contained pieces. This does not mean splitting
1180
file by file. Instead, make the patch as small as possible while still
1181
keeping it as a logical unit that contains an individual change, even
1182
if it spans multiple files. This makes reviewing your patches much easier
1183
for us and greatly increases your chances of getting your patch applied.
1184

    
1185
Run the regression tests before submitting a patch so that you can
1186
verify that there are no big problems.
1187

    
1188
Patches should be posted as base64 encoded attachments (or any other
1189
encoding which ensures that the patch will not be trashed during
1190
transmission) to the ffmpeg-devel mailing list, see
1191
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1192

    
1193
It also helps quite a bit if you tell us what the patch does (for example
1194
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1195
and has no lrint()')
1196

    
1197
Also please if you send several patches, send each patch as a separate mail,
1198
do not attach several unrelated patches to the same mail.
1199

    
1200
@section New codecs or formats checklist
1201

    
1202
@enumerate
1203
@item
1204
    Did you use av_cold for codec initialization and close functions?
1205
@item
1206
    Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
1207
    AVInputFormat/AVOutputFormat struct?
1208
@item
1209
    Did you bump the minor version number in @file{avcodec.h} or
1210
    @file{avformat.h}?
1211
@item
1212
    Did you register it in @file{allcodecs.c} or @file{allformats.c}?
1213
@item
1214
    Did you add the CodecID to @file{avcodec.h}?
1215
@item
1216
    If it has a fourcc, did you add it to @file{libavformat/riff.c},
1217
    even if it is only a decoder?
1218
@item
1219
    Did you add a rule to compile the appropriate files in the Makefile?
1220
    Remember to do this even if you're just adding a format to a file that is
1221
    already being compiled by some other rule, like a raw demuxer.
1222
@item
1223
    Did you add an entry to the table of supported formats or codecs in the
1224
    documentation?
1225
@item
1226
    Did you add an entry in the Changelog?
1227
@item
1228
    If it depends on a parser or a library, did you add that dependency in
1229
    configure?
1230
@item
1231
    Did you "svn add" the appropriate files before commiting?
1232
@end enumerate
1233

    
1234
@section patch submission checklist
1235

    
1236
@enumerate
1237
@item
1238
    Do the regression tests pass with the patch applied?
1239
@item
1240
    Does @code{make checkheaders} pass with the patch applied?
1241
@item
1242
    Is the patch a unified diff?
1243
@item
1244
    Is the patch against latest FFmpeg SVN?
1245
@item
1246
    Are you subscribed to ffmpeg-dev?
1247
    (the list is subscribers only due to spam)
1248
@item
1249
    Have you checked that the changes are minimal, so that the same cannot be
1250
    achieved with a smaller patch and/or simpler final code?
1251
@item
1252
    If the change is to speed critical code, did you benchmark it?
1253
@item
1254
    If you did any benchmarks, did you provide them in the mail?
1255
@item
1256
    Have you checked that the patch does not introduce buffer overflows or
1257
    other security issues?
1258
@item
1259
    Did you test your decoder or demuxer against damaged data? If no, see
1260
    tools/trasher and the noise bitstream filter. Your decoder or demuxer
1261
    should not crash or end in a (near) infinite loop when fed damaged data.
1262
@item
1263
    Is the patch created from the root of the source tree, so it can be
1264
    applied with @code{patch -p0}?
1265
@item
1266
    Does the patch not mix functional and cosmetic changes?
1267
@item
1268
    Did you add tabs or trailing whitespace to the code? Both are forbidden.
1269
@item
1270
    Is the patch attached to the email you send?
1271
@item
1272
    Is the mime type of the patch correct? It should be text/x-diff or
1273
    text/x-patch or at least text/plain and not application/octet-stream.
1274
@item
1275
    If the patch fixes a bug, did you provide a verbose analysis of the bug?
1276
@item
1277
    If the patch fixes a bug, did you provide enough information, including
1278
    a sample, so the bug can be reproduced and the fix can be verified?
1279
    Note please do not attach samples >100k to mails but rather provide a
1280
    URL, you can upload to ftp://upload.ffmpeg.org
1281
@item
1282
    Did you provide a verbose summary about what the patch does change?
1283
@item
1284
    Did you provide a verbose explanation why it changes things like it does?
1285
@item
1286
    Did you provide a verbose summary of the user visible advantages and
1287
    disadvantages if the patch is applied?
1288
@item
1289
    Did you provide an example so we can verify the new feature added by the
1290
    patch easily?
1291
@item
1292
    If you added a new file, did you insert a license header? It should be
1293
    taken from FFmpeg, not randomly copied and pasted from somewhere else.
1294
@item
1295
    You should maintain alphabetical order in alphabetically ordered lists as
1296
    long as doing so does not break API/ABI compatibility.
1297
@item
1298
    Lines with similar content should be aligned vertically when doing so
1299
    improves readability.
1300
@item
1301
    Did you provide a suggestion for a clear commit log message?
1302
@end enumerate
1303

    
1304
@section Patch review process
1305

    
1306
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1307
clear note that the patch is not for SVN.
1308
Reviews and comments will be posted as replies to the patch on the
1309
mailing list. The patch submitter then has to take care of every comment,
1310
that can be by resubmitting a changed patch or by discussion. Resubmitted
1311
patches will themselves be reviewed like any other patch. If at some point
1312
a patch passes review with no comments then it is approved, that can for
1313
simple and small patches happen immediately while large patches will generally
1314
have to be changed and reviewed many times before they are approved.
1315
After a patch is approved it will be committed to the repository.
1316

    
1317
We will review all submitted patches, but sometimes we are quite busy so
1318
especially for large patches this can take several weeks.
1319

    
1320
When resubmitting patches, please do not make any significant changes
1321
not related to the comments received during review. Such patches will
1322
be rejected. Instead, submit  significant changes or new features as
1323
separate patches.
1324

    
1325
@section Regression tests
1326

    
1327
Before submitting a patch (or committing to the repository), you should at least
1328
test that you did not break anything.
1329

    
1330
The regression tests build a synthetic video stream and a synthetic
1331
audio stream. These are then encoded and decoded with all codecs or
1332
formats. The CRC (or MD5) of each generated file is recorded in a
1333
result file. A 'diff' is launched to compare the reference results and
1334
the result file.
1335

    
1336
The regression tests then go on to test the FFserver code with a
1337
limited set of streams. It is important that this step runs correctly
1338
as well.
1339

    
1340
Run 'make test' to test all the codecs and formats.
1341

    
1342
Run 'make fulltest' to test all the codecs, formats and FFserver.
1343

    
1344
[Of course, some patches may change the results of the regression tests. In
1345
this case, the reference results of the regression tests shall be modified
1346
accordingly].
1347

    
1348
@bye