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

    
585
@code{X} means that encoding (resp. decoding) is supported.
586

    
587
@code{E} means that support is provided through an external library.
588

    
589
@code{I} means that an integer-only version is available, too (ensures high
590
performance on systems without hardware floating point support).
591

    
592
@section Subtitle Formats
593

    
594
@multitable @columnfractions .4 .1 .1 .1 .1 .1
595
@item Name @tab Muxing @tab Demuxing @tab Encoding @tab Decoding
596
@item SSA/ASS      @tab X @tab X
597
@item DVB          @tab X @tab X @tab X @tab X
598
@item DVD          @tab X @tab X @tab X @tab X
599
@item XSUB         @tab   @tab   @tab   @tab X
600
@end multitable
601

    
602
@code{X} means that the feature is supported.
603

    
604
@section Network Protocols
605

    
606
@multitable @columnfractions .4 .1 .1 .1 .1 .1
607
@item Name         @tab Support
608
@item file         @tab X
609
@item Gopher       @tab X
610
@item HTTP         @tab X
611
@item pipe         @tab X
612
@item RTP          @tab X
613
@item TCP          @tab X
614
@item UDP          @tab X
615
@end multitable
616

    
617
@code{X} means that the protocol is supported.
618

    
619

    
620
@chapter Platform Specific information
621

    
622
@section BSD
623

    
624
BSD make will not build FFmpeg, you need to install and use GNU Make
625
(@file{gmake}).
626

    
627
@section Windows
628

    
629
To get help and instructions for building FFmpeg under Windows, check out
630
the FFmpeg Windows Help Forum at
631
@url{http://ffmpeg.arrozcru.org/}.
632

    
633
@subsection Native Windows compilation
634

    
635
FFmpeg can be built to run natively on Windows using the MinGW tools. Install
636
the latest versions of MSYS and MinGW from @url{http://www.mingw.org/}.
637
You can find detailed installation
638
instructions in the download section and the FAQ.
639

    
640
FFmpeg does not build out-of-the-box with the packages the automated MinGW
641
installer provides. It also requires coreutils to be installed and many other
642
packages updated to the latest version. The minimum version for some packages
643
are listed below:
644

    
645
@itemize
646
@item bash 3.1
647
@item msys-make 3.81-2 (note: not mingw32-make)
648
@item w32api 3.13
649
@item mingw-runtime 3.15
650
@end itemize
651

    
652
You will also need to pass @code{-fno-common} to the compiler to work around
653
a GCC bug (see @url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216}).
654

    
655
Within the MSYS shell, configure and make with:
656

    
657
@example
658
./configure --enable-memalign-hack --extra-cflags=-fno-common
659
make
660
make install
661
@end example
662

    
663
This will install @file{ffmpeg.exe} along with many other development files
664
to @file{/usr/local}. You may specify another install path using the
665
@code{--prefix} option in @file{configure}.
666

    
667
Notes:
668

    
669
@itemize
670

    
671
@item In order to compile vhooks, you must have a POSIX-compliant libdl in
672
your MinGW system. Get dlfcn-win32 from
673
@url{http://code.google.com/p/dlfcn-win32}.
674

    
675
@item In order to compile FFplay, you must have the MinGW development library
676
of SDL. Get it from @url{http://www.libsdl.org}.
677
Edit the @file{bin/sdl-config} script so that it points to the correct prefix
678
where SDL was installed. Verify that @file{sdl-config} can be launched from
679
the MSYS command line.
680

    
681
@item By using @code{./configure --enable-shared} when configuring FFmpeg,
682
you can build libavutil, libavcodec and libavformat as DLLs.
683

    
684
@end itemize
685

    
686
@subsection Microsoft Visual C++ compatibility
687

    
688
As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
689
want to use the libav* libraries in your own applications, you can still
690
compile those applications using MSVC++. But the libav* libraries you link
691
to @emph{must} be built with MinGW. However, you will not be able to debug
692
inside the libav* libraries, since MSVC++ does not recognize the debug
693
symbols generated by GCC.
694
We strongly recommend you to move over from MSVC++ to MinGW tools.
695

    
696
This description of how to use the FFmpeg libraries with MSVC++ is based on
697
Microsoft Visual C++ 2005 Express Edition. If you have a different version,
698
you might have to modify the procedures slightly.
699

    
700
@subsubsection Using static libraries
701

    
702
Assuming you have just built and installed FFmpeg in @file{/usr/local}.
703

    
704
@enumerate
705

    
706
@item Create a new console application ("File / New / Project") and then
707
select "Win32 Console Application". On the appropriate page of the
708
Application Wizard, uncheck the "Precompiled headers" option.
709

    
710
@item Write the source code for your application, or, for testing, just
711
copy the code from an existing sample application into the source file
712
that MSVC++ has already created for you. For example, you can copy
713
@file{output_example.c} from the FFmpeg distribution.
714

    
715
@item Open the "Project / Properties" dialog box. In the "Configuration"
716
combo box, select "All Configurations" so that the changes you make will
717
affect both debug and release builds. In the tree view on the left hand
718
side, select "C/C++ / General", then edit the "Additional Include
719
Directories" setting to contain the path where the FFmpeg includes were
720
installed (i.e. @file{c:\msys\1.0\local\include}).
721
Do not add MinGW's include directory here, or the include files will
722
conflict with MSVC's.
723

    
724
@item Still in the "Project / Properties" dialog box, select
725
"Linker / General" from the tree view and edit the
726
"Additional Library Directories" setting to contain the @file{lib}
727
directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
728
the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
729
and the directory where MinGW's GCC libs are installed
730
(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
731
"Linker / Input" from the tree view, and add the files @file{libavformat.a},
732
@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
733
@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
734
to the end of "Additional Dependencies".
735

    
736
@item Now, select "C/C++ / Code Generation" from the tree view. Select
737
"Debug" in the "Configuration" combo box. Make sure that "Runtime
738
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
739
the "Configuration" combo box and make sure that "Runtime Library" is
740
set to "Multi-threaded DLL".
741

    
742
@item Click "OK" to close the "Project / Properties" dialog box.
743

    
744
@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
745
Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
746
and install it in MSVC++'s include directory
747
(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
748

    
749
@item MSVC++ also does not understand the @code{inline} keyword used by
750
FFmpeg, so you must add this line before @code{#include}ing libav*:
751
@example
752
#define inline _inline
753
@end example
754

    
755
@item Build your application, everything should work.
756

    
757
@end enumerate
758

    
759
@subsubsection Using shared libraries
760

    
761
This is how to create DLL and LIB files that are compatible with MSVC++:
762

    
763
@enumerate
764

    
765
@item Add a call to @file{vcvars32.bat} (which sets up the environment
766
variables for the Visual C++ tools) as the first line of @file{msys.bat}.
767
The standard location for @file{vcvars32.bat} is
768
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
769
and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
770
If this corresponds to your setup, add the following line as the first line
771
of @file{msys.bat}:
772

    
773
@example
774
call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
775
@end example
776

    
777
Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
778
and run @file{c:\msys\1.0\msys.bat} from there.
779

    
780
@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
781
from @file{Microsoft (R) Library Manager}, this means your environment
782
variables are set up correctly, the @file{Microsoft (R) Library Manager}
783
is on the path and will be used by FFmpeg to create
784
MSVC++-compatible import libraries.
785

    
786
@item Build FFmpeg with
787

    
788
@example
789
./configure --enable-shared --enable-memalign-hack
790
make
791
make install
792
@end example
793

    
794
Your install path (@file{/usr/local/} by default) should now have the
795
necessary DLL and LIB files under the @file{bin} directory.
796

    
797
@end enumerate
798

    
799
To use those files with MSVC++, do the same as you would do with
800
the static libraries, as described above. But in Step 4,
801
you should only need to add the directory where the LIB files are installed
802
(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
803
installed in the @file{bin} directory. And instead of adding @file{libxx.a}
804
files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
805
@file{avutil.lib}. There should be no need for @file{libmingwex.a},
806
@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
807
statically linked into the DLLs. The @file{bin} directory contains a bunch
808
of DLL files, but the ones that are actually used to run your application
809
are the ones with a major version number in their filenames
810
(i.e. @file{avcodec-51.dll}).
811

    
812
@subsection Cross compilation for Windows with Linux
813

    
814
You must use the MinGW cross compilation tools available at
815
@url{http://www.mingw.org/}.
816

    
817
Then configure FFmpeg with the following options:
818
@example
819
./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
820
@end example
821
(you can change the cross-prefix according to the prefix chosen for the
822
MinGW tools).
823

    
824
Then you can easily test FFmpeg with Wine
825
(@url{http://www.winehq.com/}).
826

    
827
@subsection Compilation under Cygwin
828

    
829
The main issue with the 1.5.x Cygwin versions is that newlib, its C library,
830
does not contain llrint().  You need to upgrade to the unstable 1.7.x versions,
831
or leverage the implementation in MinGW (as explained below).
832

    
833
Just install your Cygwin with all the "Base" packages, plus the
834
following "Devel" ones:
835
@example
836
binutils, gcc-core, make, subversion, mingw-runtime, diffutils
837
@end example
838

    
839
The experimental gcc4 package is still buggy, hence please
840
use the official gcc 3.4.4 or a 4.2.x compiled from source by yourself.
841

    
842
Install the current binutils-20080624-2 as they work fine (the old
843
binutils-20060709-1 proved buggy on shared builds).
844

    
845
Then create a small library that just contains llrint():
846

    
847
@example
848
ar x /usr/lib/mingw/libmingwex.a llrint.o
849
ar cq /usr/local/lib/libllrint.a llrint.o
850
@end example
851

    
852
Then run
853

    
854
@example
855
./configure --enable-static --disable-shared  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
856
@end example
857

    
858
to make a static build or
859

    
860
@example
861
./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
862
@end example
863

    
864
to build shared libraries.
865

    
866
If you want to build FFmpeg with additional libraries, download Cygwin
867
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository:
868
@example
869
libogg-devel, libvorbis-devel
870
@end example
871

    
872
These library packages are only available from Cygwin Ports
873
(@url{http://sourceware.org/cygwinports/}) :
874

    
875
@example
876
yasm, libSDL-devel, libdirac-devel, libfaac-devel, libfaad-devel, libgsm-devel,
877
libmp3lame-devel, libschroedinger1.0-devel, speex-devel, libtheora-devel,
878
libxvidcore-devel
879
@end example
880

    
881
The recommendation for libnut and x264 is to build them from source by
882
yourself, as they evolve too quickly for Cygwin Ports to be up to date.
883

    
884
Cygwin 1.7.x has IPv6 support. You can add IPv6 to Cygwin 1.5.x by means
885
of the @code{libgetaddrinfo-devel} package, available at Cygwin Ports.
886

    
887
@subsection Crosscompilation for Windows under Cygwin
888

    
889
With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
890

    
891
Just install your Cygwin as explained before, plus these additional
892
"Devel" packages:
893
@example
894
gcc-mingw-core, mingw-runtime, mingw-zlib
895
@end example
896

    
897
and add some special flags to your configure invocation.
898

    
899
For a static build run
900
@example
901
./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
902
@end example
903

    
904
and for a build with shared libraries
905
@example
906
./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
907
@end example
908

    
909
@section BeOS
910

    
911
BeOS support is broken in mysterious ways.
912

    
913
@section OS/2
914

    
915
For information about compiling FFmpeg on OS/2 see
916
@url{http://www.edm2.com/index.php/FFmpeg}.
917

    
918
@chapter Developers Guide
919

    
920
@section API
921
@itemize @bullet
922
@item libavcodec is the library containing the codecs (both encoding and
923
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
924

    
925
@item libavformat is the library containing the file format handling (mux and
926
demux code for several formats). Look at @file{ffplay.c} to use it in a
927
player. See @file{output_example.c} to use it to generate audio or video
928
streams.
929

    
930
@end itemize
931

    
932
@section Integrating libavcodec or libavformat in your program
933

    
934
You can integrate all the source code of the libraries to link them
935
statically to avoid any version problem. All you need is to provide a
936
'config.mak' and a 'config.h' in the parent directory. See the defines
937
generated by ./configure to understand what is needed.
938

    
939
You can use libavcodec or libavformat in your commercial program, but
940
@emph{any patch you make must be published}. The best way to proceed is
941
to send your patches to the FFmpeg mailing list.
942

    
943
@node Coding Rules
944
@section Coding Rules
945

    
946
FFmpeg is programmed in the ISO C90 language with a few additional
947
features from ISO C99, namely:
948
@itemize @bullet
949
@item
950
the @samp{inline} keyword;
951
@item
952
@samp{//} comments;
953
@item
954
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
955
@item
956
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
957
@end itemize
958

    
959
These features are supported by all compilers we care about, so we will not
960
accept patches to remove their use unless they absolutely do not impair
961
clarity and performance.
962

    
963
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
964
compiles with several other compilers, such as the Compaq ccc compiler
965
or Sun Studio 9, and we would like to keep it that way unless it would
966
be exceedingly involved. To ensure compatibility, please do not use any
967
additional C99 features or GCC extensions. Especially watch out for:
968
@itemize @bullet
969
@item
970
mixing statements and declarations;
971
@item
972
@samp{long long} (use @samp{int64_t} instead);
973
@item
974
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
975
@item
976
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
977
@end itemize
978

    
979
Indent size is 4.
980
The presentation is the one specified by 'indent -i4 -kr -nut'.
981
The TAB character is forbidden outside of Makefiles as is any
982
form of trailing whitespace. Commits containing either will be
983
rejected by the Subversion repository.
984

    
985
The main priority in FFmpeg is simplicity and small code size in order to
986
minimize the bug count.
987

    
988
Comments: Use the JavaDoc/Doxygen
989
format (see examples below) so that code documentation
990
can be generated automatically. All nontrivial functions should have a comment
991
above them explaining what the function does, even if it is just one sentence.
992
All structures and their member variables should be documented, too.
993
@example
994
/**
995
 * @@file mpeg.c
996
 * MPEG codec.
997
 * @@author ...
998
 */
999

    
1000
/**
1001
 * Summary sentence.
1002
 * more text ...
1003
 * ...
1004
 */
1005
typedef struct Foobar@{
1006
    int var1; /**< var1 description */
1007
    int var2; ///< var2 description
1008
    /** var3 description */
1009
    int var3;
1010
@} Foobar;
1011

    
1012
/**
1013
 * Summary sentence.
1014
 * more text ...
1015
 * ...
1016
 * @@param my_parameter description of my_parameter
1017
 * @@return return value description
1018
 */
1019
int myfunc(int my_parameter)
1020
...
1021
@end example
1022

    
1023
fprintf and printf are forbidden in libavformat and libavcodec,
1024
please use av_log() instead.
1025

    
1026
Casts should be used only when necessary. Unneeded parentheses
1027
should also be avoided if they don't make the code easier to understand.
1028

    
1029
@section Development Policy
1030

    
1031
@enumerate
1032
@item
1033
   Contributions should be licensed under the LGPL 2.1, including an
1034
   "or any later version" clause, or the MIT license.  GPL 2 including
1035
   an "or any later version" clause is also acceptable, but LGPL is
1036
   preferred.
1037
@item
1038
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
1039
   enabled code which breaks compilation or compiles but does not work or
1040
   breaks the regression tests)
1041
   You can commit unfinished stuff (for testing etc), but it must be disabled
1042
   (#ifdef etc) by default so it does not interfere with other developers'
1043
   work.
1044
@item
1045
   You do not have to over-test things. If it works for you, and you think it
1046
   should work for others, then commit. If your code has problems
1047
   (portability, triggers compiler bugs, unusual environment etc) they will be
1048
   reported and eventually fixed.
1049
@item
1050
   Do not commit unrelated changes together, split them into self-contained
1051
   pieces. Also do not forget that if part B depends on part A, but A does not
1052
   depend on B, then A can and should be committed first and separate from B.
1053
   Keeping changes well split into self-contained parts makes reviewing and
1054
   understanding them on the commit log mailing list easier. This also helps
1055
   in case of debugging later on.
1056
   Also if you have doubts about splitting or not splitting, do not hesitate to
1057
   ask/discuss it on the developer mailing list.
1058
@item
1059
   Do not change behavior of the program (renaming options etc) without
1060
   first discussing it on the ffmpeg-devel mailing list. Do not remove
1061
   functionality from the code. Just improve!
1062

    
1063
   Note: Redundant code can be removed.
1064
@item
1065
   Do not commit changes to the build system (Makefiles, configure script)
1066
   which change behavior, defaults etc, without asking first. The same
1067
   applies to compiler warning fixes, trivial looking fixes and to code
1068
   maintained by other developers. We usually have a reason for doing things
1069
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
1070
   list, and if the code maintainers say OK, you may commit. This does not
1071
   apply to files you wrote and/or maintain.
1072
@item
1073
   We refuse source indentation and other cosmetic changes if they are mixed
1074
   with functional changes, such commits will be rejected and removed. Every
1075
   developer has his own indentation style, you should not change it. Of course
1076
   if you (re)write something, you can use your own style, even though we would
1077
   prefer if the indentation throughout FFmpeg was consistent (Many projects
1078
   force a given indentation style - we do not.). If you really need to make
1079
   indentation changes (try to avoid this), separate them strictly from real
1080
   changes.
1081

    
1082
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1083
   then either do NOT change the indentation of the inner part within (do not
1084
   move it to the right)! or do so in a separate commit
1085
@item
1086
   Always fill out the commit log message. Describe in a few lines what you
1087
   changed and why. You can refer to mailing list postings if you fix a
1088
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1089
@item
1090
   If you apply a patch by someone else, include the name and email address in
1091
   the log message. Since the ffmpeg-cvslog mailing list is publicly
1092
   archived you should add some SPAM protection to the email address. Send an
1093
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
1094
   you applied the patch.
1095
@item
1096
   When applying patches that have been discussed (at length) on the mailing
1097
   list, reference the thread in the log message.
1098
@item
1099
    Do NOT commit to code actively maintained by others without permission.
1100
    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
1101
    timeframe (12h for build failures and security fixes, 3 days small changes,
1102
    1 week for big patches) then commit your patch if you think it is OK.
1103
    Also note, the maintainer can simply ask for more time to review!
1104
@item
1105
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1106
    are sent there and reviewed by all the other developers. Bugs and possible
1107
    improvements or general questions regarding commits are discussed there. We
1108
    expect you to react if problems with your code are uncovered.
1109
@item
1110
    Update the documentation if you change behavior or add features. If you are
1111
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1112
    maintainer(s) will review and commit your stuff.
1113
@item
1114
    Try to keep important discussions and requests (also) on the public
1115
    developer mailing list, so that all developers can benefit from them.
1116
@item
1117
    Never write to unallocated memory, never write over the end of arrays,
1118
    always check values read from some untrusted source before using them
1119
    as array index or other risky things.
1120
@item
1121
    Remember to check if you need to bump versions for the specific libav
1122
    parts (libavutil, libavcodec, libavformat) you are changing. You need
1123
    to change the version integer.
1124
    Incrementing the first component means no backward compatibility to
1125
    previous versions (e.g. removal of a function from the public API).
1126
    Incrementing the second component means backward compatible change
1127
    (e.g. addition of a function to the public API or extension of an
1128
    existing data structure).
1129
    Incrementing the third component means a noteworthy binary compatible
1130
    change (e.g. encoder bug fix that matters for the decoder).
1131
@item
1132
    Compiler warnings indicate potential bugs or code with bad style. If a type of
1133
    warning always points to correct and clean code, that warning should
1134
    be disabled, not the code changed.
1135
    Thus the remaining warnings can either be bugs or correct code.
1136
    If it is a bug, the bug has to be fixed. If it is not, the code should
1137
    be changed to not generate a warning unless that causes a slowdown
1138
    or obfuscates the code.
1139
@item
1140
    If you add a new file, give it a proper license header. Do not copy and
1141
    paste it from a random place, use an existing file as template.
1142
@end enumerate
1143

    
1144
We think our rules are not too hard. If you have comments, contact us.
1145

    
1146
Note, these rules are mostly borrowed from the MPlayer project.
1147

    
1148
@section Submitting patches
1149

    
1150
First, (@pxref{Coding Rules}) above if you did not yet.
1151

    
1152
When you submit your patch, try to send a unified diff (diff '-up'
1153
option). We cannot read other diffs :-)
1154

    
1155
Also please do not submit a patch which contains several unrelated changes.
1156
Split it into separate, self-contained pieces. This does not mean splitting
1157
file by file. Instead, make the patch as small as possible while still
1158
keeping it as a logical unit that contains an individual change, even
1159
if it spans multiple files. This makes reviewing your patches much easier
1160
for us and greatly increases your chances of getting your patch applied.
1161

    
1162
Run the regression tests before submitting a patch so that you can
1163
verify that there are no big problems.
1164

    
1165
Patches should be posted as base64 encoded attachments (or any other
1166
encoding which ensures that the patch will not be trashed during
1167
transmission) to the ffmpeg-devel mailing list, see
1168
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1169

    
1170
It also helps quite a bit if you tell us what the patch does (for example
1171
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1172
and has no lrint()')
1173

    
1174
Also please if you send several patches, send each patch as a separate mail,
1175
do not attach several unrelated patches to the same mail.
1176

    
1177
@section New codecs or formats checklist
1178

    
1179
@enumerate
1180
@item
1181
    Did you use av_cold for codec initialization and close functions?
1182
@item
1183
    Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
1184
    AVInputFormat/AVOutputFormat struct?
1185
@item
1186
    Did you bump the minor version number in @file{avcodec.h} or
1187
    @file{avformat.h}?
1188
@item
1189
    Did you register it in @file{allcodecs.c} or @file{allformats.c}?
1190
@item
1191
    Did you add the CodecID to @file{avcodec.h}?
1192
@item
1193
    If it has a fourcc, did you add it to @file{libavformat/riff.c},
1194
    even if it is only a decoder?
1195
@item
1196
    Did you add a rule to compile the appropriate files in the Makefile?
1197
    Remember to do this even if you're just adding a format to a file that is
1198
    already being compiled by some other rule, like a raw demuxer.
1199
@item
1200
    Did you add an entry to the table of supported formats or codecs in the
1201
    documentation?
1202
@item
1203
    Did you add an entry in the Changelog?
1204
@item
1205
    If it depends on a parser or a library, did you add that dependency in
1206
    configure?
1207
@item
1208
    Did you "svn add" the appropriate files before commiting?
1209
@end enumerate
1210

    
1211
@section patch submission checklist
1212

    
1213
@enumerate
1214
@item
1215
    Do the regression tests pass with the patch applied?
1216
@item
1217
    Does @code{make checkheaders} pass with the patch applied?
1218
@item
1219
    Is the patch a unified diff?
1220
@item
1221
    Is the patch against latest FFmpeg SVN?
1222
@item
1223
    Are you subscribed to ffmpeg-dev?
1224
    (the list is subscribers only due to spam)
1225
@item
1226
    Have you checked that the changes are minimal, so that the same cannot be
1227
    achieved with a smaller patch and/or simpler final code?
1228
@item
1229
    If the change is to speed critical code, did you benchmark it?
1230
@item
1231
    If you did any benchmarks, did you provide them in the mail?
1232
@item
1233
    Have you checked that the patch does not introduce buffer overflows or
1234
    other security issues?
1235
@item
1236
    Did you test your decoder or demuxer against damaged data? If no, see
1237
    tools/trasher and the noise bitstream filter. Your decoder or demuxer
1238
    should not crash or end in a (near) infinite loop when fed damaged data.
1239
@item
1240
    Is the patch created from the root of the source tree, so it can be
1241
    applied with @code{patch -p0}?
1242
@item
1243
    Does the patch not mix functional and cosmetic changes?
1244
@item
1245
    Did you add tabs or trailing whitespace to the code? Both are forbidden.
1246
@item
1247
    Is the patch attached to the email you send?
1248
@item
1249
    Is the mime type of the patch correct? It should be text/x-diff or
1250
    text/x-patch or at least text/plain and not application/octet-stream.
1251
@item
1252
    If the patch fixes a bug, did you provide a verbose analysis of the bug?
1253
@item
1254
    If the patch fixes a bug, did you provide enough information, including
1255
    a sample, so the bug can be reproduced and the fix can be verified?
1256
    Note please do not attach samples >100k to mails but rather provide a
1257
    URL, you can upload to ftp://upload.ffmpeg.org
1258
@item
1259
    Did you provide a verbose summary about what the patch does change?
1260
@item
1261
    Did you provide a verbose explanation why it changes things like it does?
1262
@item
1263
    Did you provide a verbose summary of the user visible advantages and
1264
    disadvantages if the patch is applied?
1265
@item
1266
    Did you provide an example so we can verify the new feature added by the
1267
    patch easily?
1268
@item
1269
    If you added a new file, did you insert a license header? It should be
1270
    taken from FFmpeg, not randomly copied and pasted from somewhere else.
1271
@item
1272
    You should maintain alphabetical order in alphabetically ordered lists as
1273
    long as doing so does not break API/ABI compatibility.
1274
@item
1275
    Lines with similar content should be aligned vertically when doing so
1276
    improves readability.
1277
@item
1278
    Did you provide a suggestion for a clear commit log message?
1279
@end enumerate
1280

    
1281
@section Patch review process
1282

    
1283
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1284
clear note that the patch is not for SVN.
1285
Reviews and comments will be posted as replies to the patch on the
1286
mailing list. The patch submitter then has to take care of every comment,
1287
that can be by resubmitting a changed patch or by discussion. Resubmitted
1288
patches will themselves be reviewed like any other patch. If at some point
1289
a patch passes review with no comments then it is approved, that can for
1290
simple and small patches happen immediately while large patches will generally
1291
have to be changed and reviewed many times before they are approved.
1292
After a patch is approved it will be committed to the repository.
1293

    
1294
We will review all submitted patches, but sometimes we are quite busy so
1295
especially for large patches this can take several weeks.
1296

    
1297
When resubmitting patches, please do not make any significant changes
1298
not related to the comments received during review. Such patches will
1299
be rejected. Instead, submit  significant changes or new features as
1300
separate patches.
1301

    
1302
@section Regression tests
1303

    
1304
Before submitting a patch (or committing to the repository), you should at least
1305
test that you did not break anything.
1306

    
1307
The regression tests build a synthetic video stream and a synthetic
1308
audio stream. These are then encoded and decoded with all codecs or
1309
formats. The CRC (or MD5) of each generated file is recorded in a
1310
result file. A 'diff' is launched to compare the reference results and
1311
the result file.
1312

    
1313
The regression tests then go on to test the FFserver code with a
1314
limited set of streams. It is important that this step runs correctly
1315
as well.
1316

    
1317
Run 'make test' to test all the codecs and formats.
1318

    
1319
Run 'make fulltest' to test all the codecs, formats and FFserver.
1320

    
1321
[Of course, some patches may change the results of the regression tests. In
1322
this case, the reference results of the regression tests shall be modified
1323
accordingly].
1324

    
1325
@bye