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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 FFplay, you must have the MinGW development library
695
of SDL. Get it from @url{http://www.libsdl.org}.
696
Edit the @file{bin/sdl-config} script so that it points to the correct prefix
697
where SDL was installed. Verify that @file{sdl-config} can be launched from
698
the MSYS command line.
699

    
700
@item By using @code{./configure --enable-shared} when configuring FFmpeg,
701
you can build libavutil, libavcodec and libavformat as DLLs.
702

    
703
@end itemize
704

    
705
@subsection Microsoft Visual C++ compatibility
706

    
707
As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
708
want to use the libav* libraries in your own applications, you can still
709
compile those applications using MSVC++. But the libav* libraries you link
710
to @emph{must} be built with MinGW. However, you will not be able to debug
711
inside the libav* libraries, since MSVC++ does not recognize the debug
712
symbols generated by GCC.
713
We strongly recommend you to move over from MSVC++ to MinGW tools.
714

    
715
This description of how to use the FFmpeg libraries with MSVC++ is based on
716
Microsoft Visual C++ 2005 Express Edition. If you have a different version,
717
you might have to modify the procedures slightly.
718

    
719
@subsubsection Using static libraries
720

    
721
Assuming you have just built and installed FFmpeg in @file{/usr/local}.
722

    
723
@enumerate
724

    
725
@item Create a new console application ("File / New / Project") and then
726
select "Win32 Console Application". On the appropriate page of the
727
Application Wizard, uncheck the "Precompiled headers" option.
728

    
729
@item Write the source code for your application, or, for testing, just
730
copy the code from an existing sample application into the source file
731
that MSVC++ has already created for you. For example, you can copy
732
@file{output_example.c} from the FFmpeg distribution.
733

    
734
@item Open the "Project / Properties" dialog box. In the "Configuration"
735
combo box, select "All Configurations" so that the changes you make will
736
affect both debug and release builds. In the tree view on the left hand
737
side, select "C/C++ / General", then edit the "Additional Include
738
Directories" setting to contain the path where the FFmpeg includes were
739
installed (i.e. @file{c:\msys\1.0\local\include}).
740
Do not add MinGW's include directory here, or the include files will
741
conflict with MSVC's.
742

    
743
@item Still in the "Project / Properties" dialog box, select
744
"Linker / General" from the tree view and edit the
745
"Additional Library Directories" setting to contain the @file{lib}
746
directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
747
the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
748
and the directory where MinGW's GCC libs are installed
749
(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
750
"Linker / Input" from the tree view, and add the files @file{libavformat.a},
751
@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
752
@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
753
to the end of "Additional Dependencies".
754

    
755
@item Now, select "C/C++ / Code Generation" from the tree view. Select
756
"Debug" in the "Configuration" combo box. Make sure that "Runtime
757
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
758
the "Configuration" combo box and make sure that "Runtime Library" is
759
set to "Multi-threaded DLL".
760

    
761
@item Click "OK" to close the "Project / Properties" dialog box.
762

    
763
@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
764
Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
765
and install it in MSVC++'s include directory
766
(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
767

    
768
@item MSVC++ also does not understand the @code{inline} keyword used by
769
FFmpeg, so you must add this line before @code{#include}ing libav*:
770
@example
771
#define inline _inline
772
@end example
773

    
774
@item Build your application, everything should work.
775

    
776
@end enumerate
777

    
778
@subsubsection Using shared libraries
779

    
780
This is how to create DLL and LIB files that are compatible with MSVC++:
781

    
782
@enumerate
783

    
784
@item Add a call to @file{vcvars32.bat} (which sets up the environment
785
variables for the Visual C++ tools) as the first line of @file{msys.bat}.
786
The standard location for @file{vcvars32.bat} is
787
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
788
and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
789
If this corresponds to your setup, add the following line as the first line
790
of @file{msys.bat}:
791

    
792
@example
793
call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
794
@end example
795

    
796
Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
797
and run @file{c:\msys\1.0\msys.bat} from there.
798

    
799
@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
800
from @file{Microsoft (R) Library Manager}, this means your environment
801
variables are set up correctly, the @file{Microsoft (R) Library Manager}
802
is on the path and will be used by FFmpeg to create
803
MSVC++-compatible import libraries.
804

    
805
@item Build FFmpeg with
806

    
807
@example
808
./configure --enable-shared --enable-memalign-hack
809
make
810
make install
811
@end example
812

    
813
Your install path (@file{/usr/local/} by default) should now have the
814
necessary DLL and LIB files under the @file{bin} directory.
815

    
816
@end enumerate
817

    
818
To use those files with MSVC++, do the same as you would do with
819
the static libraries, as described above. But in Step 4,
820
you should only need to add the directory where the LIB files are installed
821
(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
822
installed in the @file{bin} directory. And instead of adding @file{libxx.a}
823
files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
824
@file{avutil.lib}. There should be no need for @file{libmingwex.a},
825
@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
826
statically linked into the DLLs. The @file{bin} directory contains a bunch
827
of DLL files, but the ones that are actually used to run your application
828
are the ones with a major version number in their filenames
829
(i.e. @file{avcodec-51.dll}).
830

    
831
@subsection Cross compilation for Windows with Linux
832

    
833
You must use the MinGW cross compilation tools available at
834
@url{http://www.mingw.org/}.
835

    
836
Then configure FFmpeg with the following options:
837
@example
838
./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
839
@end example
840
(you can change the cross-prefix according to the prefix chosen for the
841
MinGW tools).
842

    
843
Then you can easily test FFmpeg with Wine
844
(@url{http://www.winehq.com/}).
845

    
846
@subsection Compilation under Cygwin
847

    
848
The main issue with the 1.5.x Cygwin versions is that newlib, its C library,
849
does not contain llrint().  You need to upgrade to the unstable 1.7.x versions,
850
or leverage the implementation in MinGW (as explained below).
851

    
852
Just install your Cygwin with all the "Base" packages, plus the
853
following "Devel" ones:
854
@example
855
binutils, gcc-core, make, subversion, mingw-runtime, diffutils
856
@end example
857

    
858
The experimental gcc4 package is still buggy, hence please
859
use the official gcc 3.4.4 or a 4.2.x compiled from source by yourself.
860

    
861
Install the current binutils-20080624-2 as they work fine (the old
862
binutils-20060709-1 proved buggy on shared builds).
863

    
864
Then create a small library that just contains llrint():
865

    
866
@example
867
ar x /usr/lib/mingw/libmingwex.a llrint.o
868
ar cq /usr/local/lib/libllrint.a llrint.o
869
@end example
870

    
871
Then run
872

    
873
@example
874
./configure --enable-static --disable-shared  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
875
@end example
876

    
877
to make a static build or
878

    
879
@example
880
./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
881
@end example
882

    
883
to build shared libraries.
884

    
885
If you want to build FFmpeg with additional libraries, download Cygwin
886
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository:
887
@example
888
libogg-devel, libvorbis-devel
889
@end example
890

    
891
These library packages are only available from Cygwin Ports
892
(@url{http://sourceware.org/cygwinports/}) :
893

    
894
@example
895
yasm, libSDL-devel, libdirac-devel, libfaac-devel, libfaad-devel, libgsm-devel,
896
libmp3lame-devel, libschroedinger1.0-devel, speex-devel, libtheora-devel,
897
libxvidcore-devel
898
@end example
899

    
900
The recommendation for libnut and x264 is to build them from source by
901
yourself, as they evolve too quickly for Cygwin Ports to be up to date.
902

    
903
Cygwin 1.7.x has IPv6 support. You can add IPv6 to Cygwin 1.5.x by means
904
of the @code{libgetaddrinfo-devel} package, available at Cygwin Ports.
905

    
906
@subsection Crosscompilation for Windows under Cygwin
907

    
908
With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
909

    
910
Just install your Cygwin as explained before, plus these additional
911
"Devel" packages:
912
@example
913
gcc-mingw-core, mingw-runtime, mingw-zlib
914
@end example
915

    
916
and add some special flags to your configure invocation.
917

    
918
For a static build run
919
@example
920
./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
921
@end example
922

    
923
and for a build with shared libraries
924
@example
925
./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
926
@end example
927

    
928
@section BeOS
929

    
930
BeOS support is broken in mysterious ways.
931

    
932
@section OS/2
933

    
934
For information about compiling FFmpeg on OS/2 see
935
@url{http://www.edm2.com/index.php/FFmpeg}.
936

    
937
@chapter Developers Guide
938

    
939
@section API
940
@itemize @bullet
941
@item libavcodec is the library containing the codecs (both encoding and
942
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
943

    
944
@item libavformat is the library containing the file format handling (mux and
945
demux code for several formats). Look at @file{ffplay.c} to use it in a
946
player. See @file{output_example.c} to use it to generate audio or video
947
streams.
948

    
949
@end itemize
950

    
951
@section Integrating libavcodec or libavformat in your program
952

    
953
You can integrate all the source code of the libraries to link them
954
statically to avoid any version problem. All you need is to provide a
955
'config.mak' and a 'config.h' in the parent directory. See the defines
956
generated by ./configure to understand what is needed.
957

    
958
You can use libavcodec or libavformat in your commercial program, but
959
@emph{any patch you make must be published}. The best way to proceed is
960
to send your patches to the FFmpeg mailing list.
961

    
962
@node Coding Rules
963
@section Coding Rules
964

    
965
FFmpeg is programmed in the ISO C90 language with a few additional
966
features from ISO C99, namely:
967
@itemize @bullet
968
@item
969
the @samp{inline} keyword;
970
@item
971
@samp{//} comments;
972
@item
973
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
974
@item
975
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
976
@end itemize
977

    
978
These features are supported by all compilers we care about, so we will not
979
accept patches to remove their use unless they absolutely do not impair
980
clarity and performance.
981

    
982
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
983
compiles with several other compilers, such as the Compaq ccc compiler
984
or Sun Studio 9, and we would like to keep it that way unless it would
985
be exceedingly involved. To ensure compatibility, please do not use any
986
additional C99 features or GCC extensions. Especially watch out for:
987
@itemize @bullet
988
@item
989
mixing statements and declarations;
990
@item
991
@samp{long long} (use @samp{int64_t} instead);
992
@item
993
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
994
@item
995
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
996
@end itemize
997

    
998
Indent size is 4.
999
The presentation is the one specified by 'indent -i4 -kr -nut'.
1000
The TAB character is forbidden outside of Makefiles as is any
1001
form of trailing whitespace. Commits containing either will be
1002
rejected by the Subversion repository.
1003

    
1004
The main priority in FFmpeg is simplicity and small code size in order to
1005
minimize the bug count.
1006

    
1007
Comments: Use the JavaDoc/Doxygen
1008
format (see examples below) so that code documentation
1009
can be generated automatically. All nontrivial functions should have a comment
1010
above them explaining what the function does, even if it is just one sentence.
1011
All structures and their member variables should be documented, too.
1012
@example
1013
/**
1014
 * @@file mpeg.c
1015
 * MPEG codec.
1016
 * @@author ...
1017
 */
1018

    
1019
/**
1020
 * Summary sentence.
1021
 * more text ...
1022
 * ...
1023
 */
1024
typedef struct Foobar@{
1025
    int var1; /**< var1 description */
1026
    int var2; ///< var2 description
1027
    /** var3 description */
1028
    int var3;
1029
@} Foobar;
1030

    
1031
/**
1032
 * Summary sentence.
1033
 * more text ...
1034
 * ...
1035
 * @@param my_parameter description of my_parameter
1036
 * @@return return value description
1037
 */
1038
int myfunc(int my_parameter)
1039
...
1040
@end example
1041

    
1042
fprintf and printf are forbidden in libavformat and libavcodec,
1043
please use av_log() instead.
1044

    
1045
Casts should be used only when necessary. Unneeded parentheses
1046
should also be avoided if they don't make the code easier to understand.
1047

    
1048
@section Development Policy
1049

    
1050
@enumerate
1051
@item
1052
   Contributions should be licensed under the LGPL 2.1, including an
1053
   "or any later version" clause, or the MIT license.  GPL 2 including
1054
   an "or any later version" clause is also acceptable, but LGPL is
1055
   preferred.
1056
@item
1057
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
1058
   enabled code which breaks compilation or compiles but does not work or
1059
   breaks the regression tests)
1060
   You can commit unfinished stuff (for testing etc), but it must be disabled
1061
   (#ifdef etc) by default so it does not interfere with other developers'
1062
   work.
1063
@item
1064
   You do not have to over-test things. If it works for you, and you think it
1065
   should work for others, then commit. If your code has problems
1066
   (portability, triggers compiler bugs, unusual environment etc) they will be
1067
   reported and eventually fixed.
1068
@item
1069
   Do not commit unrelated changes together, split them into self-contained
1070
   pieces. Also do not forget that if part B depends on part A, but A does not
1071
   depend on B, then A can and should be committed first and separate from B.
1072
   Keeping changes well split into self-contained parts makes reviewing and
1073
   understanding them on the commit log mailing list easier. This also helps
1074
   in case of debugging later on.
1075
   Also if you have doubts about splitting or not splitting, do not hesitate to
1076
   ask/discuss it on the developer mailing list.
1077
@item
1078
   Do not change behavior of the program (renaming options etc) without
1079
   first discussing it on the ffmpeg-devel mailing list. Do not remove
1080
   functionality from the code. Just improve!
1081

    
1082
   Note: Redundant code can be removed.
1083
@item
1084
   Do not commit changes to the build system (Makefiles, configure script)
1085
   which change behavior, defaults etc, without asking first. The same
1086
   applies to compiler warning fixes, trivial looking fixes and to code
1087
   maintained by other developers. We usually have a reason for doing things
1088
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
1089
   list, and if the code maintainers say OK, you may commit. This does not
1090
   apply to files you wrote and/or maintain.
1091
@item
1092
   We refuse source indentation and other cosmetic changes if they are mixed
1093
   with functional changes, such commits will be rejected and removed. Every
1094
   developer has his own indentation style, you should not change it. Of course
1095
   if you (re)write something, you can use your own style, even though we would
1096
   prefer if the indentation throughout FFmpeg was consistent (Many projects
1097
   force a given indentation style - we do not.). If you really need to make
1098
   indentation changes (try to avoid this), separate them strictly from real
1099
   changes.
1100

    
1101
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1102
   then either do NOT change the indentation of the inner part within (do not
1103
   move it to the right)! or do so in a separate commit
1104
@item
1105
   Always fill out the commit log message. Describe in a few lines what you
1106
   changed and why. You can refer to mailing list postings if you fix a
1107
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1108
@item
1109
   If you apply a patch by someone else, include the name and email address in
1110
   the log message. Since the ffmpeg-cvslog mailing list is publicly
1111
   archived you should add some SPAM protection to the email address. Send an
1112
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
1113
   you applied the patch.
1114
@item
1115
   When applying patches that have been discussed (at length) on the mailing
1116
   list, reference the thread in the log message.
1117
@item
1118
    Do NOT commit to code actively maintained by others without permission.
1119
    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
1120
    timeframe (12h for build failures and security fixes, 3 days small changes,
1121
    1 week for big patches) then commit your patch if you think it is OK.
1122
    Also note, the maintainer can simply ask for more time to review!
1123
@item
1124
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1125
    are sent there and reviewed by all the other developers. Bugs and possible
1126
    improvements or general questions regarding commits are discussed there. We
1127
    expect you to react if problems with your code are uncovered.
1128
@item
1129
    Update the documentation if you change behavior or add features. If you are
1130
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1131
    maintainer(s) will review and commit your stuff.
1132
@item
1133
    Try to keep important discussions and requests (also) on the public
1134
    developer mailing list, so that all developers can benefit from them.
1135
@item
1136
    Never write to unallocated memory, never write over the end of arrays,
1137
    always check values read from some untrusted source before using them
1138
    as array index or other risky things.
1139
@item
1140
    Remember to check if you need to bump versions for the specific libav
1141
    parts (libavutil, libavcodec, libavformat) you are changing. You need
1142
    to change the version integer.
1143
    Incrementing the first component means no backward compatibility to
1144
    previous versions (e.g. removal of a function from the public API).
1145
    Incrementing the second component means backward compatible change
1146
    (e.g. addition of a function to the public API or extension of an
1147
    existing data structure).
1148
    Incrementing the third component means a noteworthy binary compatible
1149
    change (e.g. encoder bug fix that matters for the decoder).
1150
@item
1151
    Compiler warnings indicate potential bugs or code with bad style. If a type of
1152
    warning always points to correct and clean code, that warning should
1153
    be disabled, not the code changed.
1154
    Thus the remaining warnings can either be bugs or correct code.
1155
    If it is a bug, the bug has to be fixed. If it is not, the code should
1156
    be changed to not generate a warning unless that causes a slowdown
1157
    or obfuscates the code.
1158
@item
1159
    If you add a new file, give it a proper license header. Do not copy and
1160
    paste it from a random place, use an existing file as template.
1161
@end enumerate
1162

    
1163
We think our rules are not too hard. If you have comments, contact us.
1164

    
1165
Note, these rules are mostly borrowed from the MPlayer project.
1166

    
1167
@section Submitting patches
1168

    
1169
First, (@pxref{Coding Rules}) above if you did not yet.
1170

    
1171
When you submit your patch, try to send a unified diff (diff '-up'
1172
option). We cannot read other diffs :-)
1173

    
1174
Also please do not submit a patch which contains several unrelated changes.
1175
Split it into separate, self-contained pieces. This does not mean splitting
1176
file by file. Instead, make the patch as small as possible while still
1177
keeping it as a logical unit that contains an individual change, even
1178
if it spans multiple files. This makes reviewing your patches much easier
1179
for us and greatly increases your chances of getting your patch applied.
1180

    
1181
Run the regression tests before submitting a patch so that you can
1182
verify that there are no big problems.
1183

    
1184
Patches should be posted as base64 encoded attachments (or any other
1185
encoding which ensures that the patch will not be trashed during
1186
transmission) to the ffmpeg-devel mailing list, see
1187
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1188

    
1189
It also helps quite a bit if you tell us what the patch does (for example
1190
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1191
and has no lrint()')
1192

    
1193
Also please if you send several patches, send each patch as a separate mail,
1194
do not attach several unrelated patches to the same mail.
1195

    
1196
@section New codecs or formats checklist
1197

    
1198
@enumerate
1199
@item
1200
    Did you use av_cold for codec initialization and close functions?
1201
@item
1202
    Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
1203
    AVInputFormat/AVOutputFormat struct?
1204
@item
1205
    Did you bump the minor version number in @file{avcodec.h} or
1206
    @file{avformat.h}?
1207
@item
1208
    Did you register it in @file{allcodecs.c} or @file{allformats.c}?
1209
@item
1210
    Did you add the CodecID to @file{avcodec.h}?
1211
@item
1212
    If it has a fourcc, did you add it to @file{libavformat/riff.c},
1213
    even if it is only a decoder?
1214
@item
1215
    Did you add a rule to compile the appropriate files in the Makefile?
1216
    Remember to do this even if you're just adding a format to a file that is
1217
    already being compiled by some other rule, like a raw demuxer.
1218
@item
1219
    Did you add an entry to the table of supported formats or codecs in the
1220
    documentation?
1221
@item
1222
    Did you add an entry in the Changelog?
1223
@item
1224
    If it depends on a parser or a library, did you add that dependency in
1225
    configure?
1226
@item
1227
    Did you "svn add" the appropriate files before commiting?
1228
@end enumerate
1229

    
1230
@section patch submission checklist
1231

    
1232
@enumerate
1233
@item
1234
    Do the regression tests pass with the patch applied?
1235
@item
1236
    Does @code{make checkheaders} pass with the patch applied?
1237
@item
1238
    Is the patch a unified diff?
1239
@item
1240
    Is the patch against latest FFmpeg SVN?
1241
@item
1242
    Are you subscribed to ffmpeg-dev?
1243
    (the list is subscribers only due to spam)
1244
@item
1245
    Have you checked that the changes are minimal, so that the same cannot be
1246
    achieved with a smaller patch and/or simpler final code?
1247
@item
1248
    If the change is to speed critical code, did you benchmark it?
1249
@item
1250
    If you did any benchmarks, did you provide them in the mail?
1251
@item
1252
    Have you checked that the patch does not introduce buffer overflows or
1253
    other security issues?
1254
@item
1255
    Did you test your decoder or demuxer against damaged data? If no, see
1256
    tools/trasher and the noise bitstream filter. Your decoder or demuxer
1257
    should not crash or end in a (near) infinite loop when fed damaged data.
1258
@item
1259
    Is the patch created from the root of the source tree, so it can be
1260
    applied with @code{patch -p0}?
1261
@item
1262
    Does the patch not mix functional and cosmetic changes?
1263
@item
1264
    Did you add tabs or trailing whitespace to the code? Both are forbidden.
1265
@item
1266
    Is the patch attached to the email you send?
1267
@item
1268
    Is the mime type of the patch correct? It should be text/x-diff or
1269
    text/x-patch or at least text/plain and not application/octet-stream.
1270
@item
1271
    If the patch fixes a bug, did you provide a verbose analysis of the bug?
1272
@item
1273
    If the patch fixes a bug, did you provide enough information, including
1274
    a sample, so the bug can be reproduced and the fix can be verified?
1275
    Note please do not attach samples >100k to mails but rather provide a
1276
    URL, you can upload to ftp://upload.ffmpeg.org
1277
@item
1278
    Did you provide a verbose summary about what the patch does change?
1279
@item
1280
    Did you provide a verbose explanation why it changes things like it does?
1281
@item
1282
    Did you provide a verbose summary of the user visible advantages and
1283
    disadvantages if the patch is applied?
1284
@item
1285
    Did you provide an example so we can verify the new feature added by the
1286
    patch easily?
1287
@item
1288
    If you added a new file, did you insert a license header? It should be
1289
    taken from FFmpeg, not randomly copied and pasted from somewhere else.
1290
@item
1291
    You should maintain alphabetical order in alphabetically ordered lists as
1292
    long as doing so does not break API/ABI compatibility.
1293
@item
1294
    Lines with similar content should be aligned vertically when doing so
1295
    improves readability.
1296
@item
1297
    Did you provide a suggestion for a clear commit log message?
1298
@end enumerate
1299

    
1300
@section Patch review process
1301

    
1302
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1303
clear note that the patch is not for SVN.
1304
Reviews and comments will be posted as replies to the patch on the
1305
mailing list. The patch submitter then has to take care of every comment,
1306
that can be by resubmitting a changed patch or by discussion. Resubmitted
1307
patches will themselves be reviewed like any other patch. If at some point
1308
a patch passes review with no comments then it is approved, that can for
1309
simple and small patches happen immediately while large patches will generally
1310
have to be changed and reviewed many times before they are approved.
1311
After a patch is approved it will be committed to the repository.
1312

    
1313
We will review all submitted patches, but sometimes we are quite busy so
1314
especially for large patches this can take several weeks.
1315

    
1316
When resubmitting patches, please do not make any significant changes
1317
not related to the comments received during review. Such patches will
1318
be rejected. Instead, submit  significant changes or new features as
1319
separate patches.
1320

    
1321
@section Regression tests
1322

    
1323
Before submitting a patch (or committing to the repository), you should at least
1324
test that you did not break anything.
1325

    
1326
The regression tests build a synthetic video stream and a synthetic
1327
audio stream. These are then encoded and decoded with all codecs or
1328
formats. The CRC (or MD5) of each generated file is recorded in a
1329
result file. A 'diff' is launched to compare the reference results and
1330
the result file.
1331

    
1332
The regression tests then go on to test the FFserver code with a
1333
limited set of streams. It is important that this step runs correctly
1334
as well.
1335

    
1336
Run 'make test' to test all the codecs and formats.
1337

    
1338
Run 'make fulltest' to test all the codecs, formats and FFserver.
1339

    
1340
[Of course, some patches may change the results of the regression tests. In
1341
this case, the reference results of the regression tests shall be modified
1342
accordingly].
1343

    
1344
@bye