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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 ADTS AAC audio            @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 ASF                       @tab X @tab X
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@item AVI                       @tab X @tab X
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@item AVM2 (Flash 9)            @tab X @tab X
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    @tab Only embedded audio is decoded.
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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 Bethsoft VID              @tab   @tab X
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    @tab Used in some games from Bethesda Softworks.
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@item BFI                       @tab   @tab X
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    @tab Brute Force & Ignorance, used in Flash Traffic: City of Angels.
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@item C93                       @tab   @tab X
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    @tab Used in the game Cyberia from Interplay.
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@item CIN                       @tab   @tab X
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    @tab Multimedia format used by Delphine Software games.
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@item Creative VOC              @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 DV                        @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 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 FLIC                      @tab   @tab X
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    @tab .fli/.flc files
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@item FLV                       @tab X @tab X
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    @tab Macromedia Flash video files
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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 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 Cinematic              @tab   @tab X
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    @tab Used in Quake II.
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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 MAXIS EA 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             @tab X @tab X
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@item MPEG audio                @tab X @tab X
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@item MPEG-1 systems            @tab X @tab X
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    @tab muxed audio and video
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@item MPEG-2 PS                 @tab X @tab X
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    @tab also known as @code{VOB} file
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@item MPEG-2 TS                 @tab   @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 MSN TCP webcam            @tab   @tab X
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    @tab Used by MSN Messenger webcam streams.
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@item MXF                       @tab X @tab X
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    @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
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@item NC                        @tab   @tab X
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    @tab NC (AVIP NC4600) cameras streams.
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@item Nullsoft Video            @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 OMA                       @tab   @tab X
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    @tab Audio format used in Sony Sonic Stage and Sony Vegas.
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@item PlayStation STR           @tab   @tab X
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@item PVA                       @tab   @tab X
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    @tab Used by TechnoTrend DVB PCI boards.
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@item raw AC-3                  @tab X @tab X
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@item raw CRI ADX audio         @tab X @tab X
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@item raw MJPEG                 @tab X @tab X
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@item raw MPEG video            @tab X @tab X
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@item raw MPEG-4 video          @tab X @tab X
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@item raw PCM 8/16/32 bits, 32/64-bit floating point, mu-law/A-law @tab X  @tab  X
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@item raw Shorten audio         @tab    @tab  X
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@item R3D REDCODE               @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 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 Sega FILM/CPK             @tab   @tab X
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    @tab Used in many Sega Saturn console games.
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@item 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 Sierra Online             @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 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 Smacker                   @tab   @tab X
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    @tab Multimedia format used by many games.
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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 WAV                       @tab X @tab X
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@item WC3 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 VQA/AUD  @tab   @tab X
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    @tab Multimedia formats used in Westwood Studios games.
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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 @tab one raw file per component
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@item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
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@item JPEG         @tab X @tab X @tab Progressive JPEG is not supported.
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@item JPEG 2000    @tab   @tab E @tab decoding supported through external library libopenjpeg
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@item PAM          @tab X @tab X @tab PAM is a PNM extension with alpha support.
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@item PCX          @tab   @tab X @tab PC Paintbrush
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@item PGM, PPM     @tab X @tab X
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@item PGMYUV       @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
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@item PNG          @tab X @tab X @tab 2/4 bpp not supported yet
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@item PTX          @tab   @tab X @tab V.Flash PTX format
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@item RAS          @tab   @tab X @tab Sun Rasterfile
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@item SGI          @tab X @tab X @tab SGI RGB image format
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@item Targa        @tab   @tab X @tab Targa (.TGA) image format
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@item TIFF         @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
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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 Video               @tab     @tab  X
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    @tab Used in certain computer games.
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@item American Laser Games Video  @tab    @tab X
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    @tab Used in games like Mad Dog McCree.
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@item AMV                    @tab     @tab  X
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    @tab Used in Chinese MP3 players.
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@item Apple Animation        @tab  X  @tab  X
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    @tab fourcc: 'rle '
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@item Apple Graphics         @tab     @tab  X
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    @tab fourcc: 'smc '
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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 Apple Video            @tab     @tab  X
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    @tab fourcc: rpza
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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 RLE           @tab     @tab  X
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    @tab fourcc: AASC
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@item AVID DNxHD             @tab   X @tab  X
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    @tab aka SMPTE VC3
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@item AVS video              @tab     @tab  X
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    @tab Video encoding used by the Creature Shock game.
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@item Bethsoft VID           @tab     @tab  X
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    @tab Used in some games from Bethesda Softworks.
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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 Cin video              @tab     @tab  X
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    @tab Codec used in Delphine Software 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           @tab     @tab  X
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    @tab fourcc: CYUV
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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 Duck TrueMotion v1     @tab     @tab  X
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    @tab fourcc: DUCK
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@item Duck TrueMotion v2     @tab     @tab  X
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    @tab fourcc: TM20
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@item DV                     @tab  X  @tab  X
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@item DXA Video              @tab     @tab  X
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    @tab Codec originally used in Feeble Files game.
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@item Electronic Arts CMV    @tab     @tab  X
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    @tab Used in NHL 95 game.
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@item Electronic Arts TGV    @tab     @tab  X
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@item Electronic Arts TGQ    @tab     @tab  X
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@item Electronic Arts TQI    @tab     @tab  X
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@item FFmpeg Video 1         @tab  X  @tab  X
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    @tab experimental lossless codec (fourcc: FFV1)
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@item Flash Screen Video     @tab  X  @tab  X
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    @tab fourcc: FSV1
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@item FLIC video             @tab     @tab  X
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@item FLV                    @tab  X  @tab  X
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    @tab Sorenson H.263 used in Flash
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@item Fraps FPS1             @tab     @tab  X
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@item H.261                  @tab  X  @tab  X
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@item H.263(+)               @tab  X  @tab  X
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    @tab also known as RealVideo 1.0
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@item H.264                  @tab  E  @tab  X
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    @tab encoding supported through external library libx264
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@item HuffYUV                @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                 @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 Indeo 3          @tab     @tab  X
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@item Interplay Video        @tab     @tab  X
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    @tab Used in Interplay .MVE files.
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@item JPEG-LS                @tab  X  @tab  X
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    @tab fourcc: MJLS, lossless and near-lossless is supported.
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@item KMVC                   @tab     @tab  X
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    @tab Codec used in Worms games.
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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                  @tab  X  @tab  X
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@item Motion Pixels Video    @tab     @tab  X
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@item MPEG-1                 @tab  X  @tab  X
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@item MPEG-2                 @tab  X  @tab  X
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@item MPEG-4                 @tab  X  @tab  X
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@item MSMPEG4 V1             @tab  X  @tab  X
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@item MSMPEG4 V2             @tab  X  @tab  X
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@item MSMPEG4 V3             @tab  X  @tab  X
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@item MSZH                   @tab     @tab  X
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    @tab Part of LCL
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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 QPEG                   @tab     @tab  X
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    @tab fourccs: QPEG, Q1.0, Q1.1
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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         @tab     @tab  X
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    @tab Texture dictionaries used by the Renderware Engine.
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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 Smacker video          @tab     @tab  X
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    @tab Video encoding used in Smacker.
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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  @tab     @tab  X
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@item Sorenson Video 1       @tab  X  @tab  X
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    @tab fourcc: SVQ1
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@item Sorenson Video 3       @tab     @tab  X
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    @tab fourcc: SVQ3
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@item Sunplus MJPEG          @tab     @tab  X
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    @tab fourcc: SP5X
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@item TechSmith Camtasia     @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 THP                    @tab     @tab  X
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    @tab Used on the Nintendo GameCube.
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@item Tiertex Seq video      @tab     @tab  X
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    @tab Codec used in DOS CD-ROM FlashBack game.
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@item VC-1                   @tab     @tab  X
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@item VMD Video              @tab     @tab  X
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    @tab Used in Sierra VMD files.
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@item VMware Video           @tab     @tab  X
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    @tab Codec used in videos captured by VMware.
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@item Westwood VQA           @tab     @tab  X
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@item Winnov WNV1            @tab     @tab  X
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@item WMV7                   @tab  X  @tab  X
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@item WMV8                   @tab  X  @tab  X
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@item WMV9                   @tab     @tab  X
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    @tab not completely working
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@item Xan/WC3                @tab     @tab  X
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    @tab Used in Wing Commander III .MVE files.
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@item ZLIB                   @tab  X  @tab  X
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    @tab part of LCL, encoder experimental
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@item ZMBV                   @tab   X @tab  X
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    @tab Encoder works only in PAL8.
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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 Audio 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 IMA ADPCM           @tab     @tab  X
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@item 8SVX audio             @tab     @tab  X
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@item AAC                    @tab  E  @tab  X
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    @tab encoding supported through external library libfaac
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@item AC-3                   @tab IX  @tab IX
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@item AMR-NB                 @tab  E  @tab  E
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    @tab supported through external library libamrnb
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@item AMR-WB                 @tab  E  @tab  E
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    @tab supported through external library libamrwb
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@item AMV IMA ADPCM          @tab     @tab  X
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    @tab Used in AMV files
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@item Apple lossless audio   @tab  X  @tab  X
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    @tab QuickTime fourcc 'alac'
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@item Apple MACE 3           @tab     @tab  X
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@item Apple MACE 6           @tab     @tab  X
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@item ATRAC 3                @tab     @tab  X
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@item CD-ROM XA ADPCM        @tab     @tab  X
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@item Cin audio              @tab     @tab  X
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    @tab Codec used in Delphine Software International games.
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@item Creative ADPCM         @tab     @tab  X
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    @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
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@item CRI ADX ADPCM          @tab  X  @tab  X
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    @tab Used in Sega Dreamcast games.
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@item DSP Group TrueSpeech   @tab     @tab  X
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@item DTS Coherent Audio     @tab     @tab  X
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@item Duck DK3 IMA ADPCM     @tab     @tab  X
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    @tab Used in some Sega Saturn console games.
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@item Duck DK4 IMA ADPCM     @tab     @tab  X
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    @tab Used in some Sega Saturn console games.
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@item DV audio               @tab     @tab  X
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@item Electronic Arts ADPCM  @tab     @tab  X
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    @tab Used in various EA titles.
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@item Enhanced AC-3          @tab     @tab  X
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@item FLAC lossless audio    @tab IX  @tab  X
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@item G.726  ADPCM           @tab  X  @tab  X
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@item GSM                    @tab  E  @tab  E
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    @tab supported through external library libgsm
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@item GSM_MS                 @tab  E  @tab  E
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    @tab supported through external library libgsm
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@item id RoQ DPCM            @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 Music Coder      @tab     @tab  X
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@item Interplay MVE DPCM     @tab     @tab  X
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    @tab Used in various Interplay computer games.
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@item ISS IMA ADPCM          @tab     @tab  X
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    @tab Used in FunCom games.
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@item MAXIS EA ADPCM         @tab     @tab  X
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    @tab Used in Sim City 3000.
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@item Microsoft ADPCM        @tab  X  @tab  X
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@item MLP/TrueHD             @tab     @tab  X
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    @tab Used in DVD-Audio and Blu-Ray discs.
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@item Monkey's Audio         @tab     @tab  X
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    @tab Only versions 3.97-3.99 are supported.
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@item MPEG audio layer 3     @tab  E  @tab IX
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    @tab encoding supported through external library LAME
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@item MPEG audio layer 2     @tab IX  @tab IX
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@item MS IMA ADPCM           @tab  X  @tab  X
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@item Musepack               @tab     @tab  X
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    @tab SV7 and SV8 are supported.
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@item Nellymoser ASAO        @tab  X  @tab  X
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@item QCELP / PureVoice      @tab     @tab  X
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@item Qdesign QDM2           @tab     @tab  X
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    @tab There are still some distortions.
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@item QT IMA ADPCM           @tab  X  @tab  X
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@item RA144                  @tab     @tab  X
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    @tab Real 14400 bit/s codec
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@item RA288                  @tab     @tab  X
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    @tab Real 28800 bit/s codec
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@item RADnet                 @tab IX  @tab IX
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    @tab Real low bitrate AC-3 codec
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@item Real COOK              @tab     @tab  X
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    @tab All versions except 5.1 are supported.
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@item Shorten                @tab     @tab  X
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@item Sierra Online DPCM     @tab     @tab  X
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    @tab Used in Sierra Online game audio files.
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@item Smacker audio          @tab     @tab  X
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@item SMJPEG IMA ADPCM       @tab     @tab  X
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    @tab Used in certain Loki game ports.
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@item Sonic                  @tab  X  @tab  X
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    @tab experimental codec
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@item Sonic lossless         @tab  X  @tab  X
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    @tab experimental codec
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@item Speex                  @tab     @tab  E
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    @tab supported through external library libspeex
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@item THP ADPCM              @tab     @tab  X
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    @tab Used on the Nintendo GameCube.
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@item True Audio (TTA)       @tab     @tab  X
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@item Vorbis                 @tab  X  @tab  X
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@item WavPack                @tab     @tab  X
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@item Westwood Studios IMA ADPCM @tab     @tab  X
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    @tab Used in Westwood Studios games like Command and Conquer.
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@item WMA v1/v2              @tab  X  @tab  X
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@item Xan DPCM               @tab     @tab  X
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    @tab Used in Origin's Wing Commander IV AVI files.
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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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@code{I} means that an integer-only version is available, too (ensures high
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performance on systems without hardware floating point support).
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@section Subtitle Formats
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@multitable @columnfractions .4 .1 .1 .1 .1 .1
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@item Name @tab Muxing @tab Demuxing @tab Encoding @tab Decoding @tab Rendering
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@item ASS/SSA      @tab X @tab X
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@item DVB          @tab X @tab X @tab X @tab X @tab X
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@item DVD          @tab X @tab X @tab X @tab X @tab X
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@item XSUB         @tab   @tab   @tab   @tab X @tab
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@end multitable
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@code{X} means that the feature is supported.
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469
@chapter Platform Specific information
470

    
471
@section BSD
472

    
473
BSD make will not build FFmpeg, you need to install and use GNU Make
474
(@file{gmake}).
475

    
476
@section Windows
477

    
478
To get help and instructions for building FFmpeg under Windows, check out
479
the FFmpeg Windows Help Forum at
480
@url{http://ffmpeg.arrozcru.org/}.
481

    
482
@subsection Native Windows compilation
483

    
484
FFmpeg can be built to run natively on Windows using the MinGW tools. Install
485
the latest versions of MSYS and MinGW from @url{http://www.mingw.org/}.
486
You can find detailed installation
487
instructions in the download section and the FAQ.
488

    
489
FFmpeg does not build out-of-the-box with the packages the automated MinGW
490
installer provides. It also requires coreutils to be installed and many other
491
packages updated to the latest version. The minimum version for some packages
492
are listed below:
493

    
494
@itemize
495
@item bash 3.1
496
@item msys-make 3.81-2 (note: not mingw32-make)
497
@item w32api 3.13
498
@item mingw-runtime 3.15
499
@end itemize
500

    
501
You will also need to pass @code{-fno-common} to the compiler to work around
502
a GCC bug (see @url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216}).
503

    
504
Within the MSYS shell, configure and make with:
505

    
506
@example
507
./configure --enable-memalign-hack --extra-cflags=-fno-common
508
make
509
make install
510
@end example
511

    
512
This will install @file{ffmpeg.exe} along with many other development files
513
to @file{/usr/local}. You may specify another install path using the
514
@code{--prefix} option in @file{configure}.
515

    
516
Notes:
517

    
518
@itemize
519

    
520
@item In order to compile vhooks, you must have a POSIX-compliant libdl in
521
your MinGW system. Get dlfcn-win32 from
522
@url{http://code.google.com/p/dlfcn-win32}.
523

    
524
@item In order to compile FFplay, you must have the MinGW development library
525
of SDL. Get it from @url{http://www.libsdl.org}.
526
Edit the @file{bin/sdl-config} script so that it points to the correct prefix
527
where SDL was installed. Verify that @file{sdl-config} can be launched from
528
the MSYS command line.
529

    
530
@item By using @code{./configure --enable-shared} when configuring FFmpeg,
531
you can build libavutil, libavcodec and libavformat as DLLs.
532

    
533
@end itemize
534

    
535
@subsection Microsoft Visual C++ compatibility
536

    
537
As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
538
want to use the libav* libraries in your own applications, you can still
539
compile those applications using MSVC++. But the libav* libraries you link
540
to @emph{must} be built with MinGW. However, you will not be able to debug
541
inside the libav* libraries, since MSVC++ does not recognize the debug
542
symbols generated by GCC.
543
We strongly recommend you to move over from MSVC++ to MinGW tools.
544

    
545
This description of how to use the FFmpeg libraries with MSVC++ is based on
546
Microsoft Visual C++ 2005 Express Edition. If you have a different version,
547
you might have to modify the procedures slightly.
548

    
549
@subsubsection Using static libraries
550

    
551
Assuming you have just built and installed FFmpeg in @file{/usr/local}.
552

    
553
@enumerate
554

    
555
@item Create a new console application ("File / New / Project") and then
556
select "Win32 Console Application". On the appropriate page of the
557
Application Wizard, uncheck the "Precompiled headers" option.
558

    
559
@item Write the source code for your application, or, for testing, just
560
copy the code from an existing sample application into the source file
561
that MSVC++ has already created for you. For example, you can copy
562
@file{output_example.c} from the FFmpeg distribution.
563

    
564
@item Open the "Project / Properties" dialog box. In the "Configuration"
565
combo box, select "All Configurations" so that the changes you make will
566
affect both debug and release builds. In the tree view on the left hand
567
side, select "C/C++ / General", then edit the "Additional Include
568
Directories" setting to contain the path where the FFmpeg includes were
569
installed (i.e. @file{c:\msys\1.0\local\include}).
570
Do not add MinGW's include directory here, or the include files will
571
conflict with MSVC's.
572

    
573
@item Still in the "Project / Properties" dialog box, select
574
"Linker / General" from the tree view and edit the
575
"Additional Library Directories" setting to contain the @file{lib}
576
directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
577
the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
578
and the directory where MinGW's GCC libs are installed
579
(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
580
"Linker / Input" from the tree view, and add the files @file{libavformat.a},
581
@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
582
@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
583
to the end of "Additional Dependencies".
584

    
585
@item Now, select "C/C++ / Code Generation" from the tree view. Select
586
"Debug" in the "Configuration" combo box. Make sure that "Runtime
587
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
588
the "Configuration" combo box and make sure that "Runtime Library" is
589
set to "Multi-threaded DLL".
590

    
591
@item Click "OK" to close the "Project / Properties" dialog box.
592

    
593
@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
594
Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
595
and install it in MSVC++'s include directory
596
(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
597

    
598
@item MSVC++ also does not understand the @code{inline} keyword used by
599
FFmpeg, so you must add this line before @code{#include}ing libav*:
600
@example
601
#define inline _inline
602
@end example
603

    
604
@item Build your application, everything should work.
605

    
606
@end enumerate
607

    
608
@subsubsection Using shared libraries
609

    
610
This is how to create DLL and LIB files that are compatible with MSVC++:
611

    
612
@enumerate
613

    
614
@item Add a call to @file{vcvars32.bat} (which sets up the environment
615
variables for the Visual C++ tools) as the first line of @file{msys.bat}.
616
The standard location for @file{vcvars32.bat} is
617
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
618
and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
619
If this corresponds to your setup, add the following line as the first line
620
of @file{msys.bat}:
621

    
622
@example
623
call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
624
@end example
625

    
626
Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
627
and run @file{c:\msys\1.0\msys.bat} from there.
628

    
629
@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
630
from @file{Microsoft (R) Library Manager}, this means your environment
631
variables are set up correctly, the @file{Microsoft (R) Library Manager}
632
is on the path and will be used by FFmpeg to create
633
MSVC++-compatible import libraries.
634

    
635
@item Build FFmpeg with
636

    
637
@example
638
./configure --enable-shared --enable-memalign-hack
639
make
640
make install
641
@end example
642

    
643
Your install path (@file{/usr/local/} by default) should now have the
644
necessary DLL and LIB files under the @file{bin} directory.
645

    
646
@end enumerate
647

    
648
To use those files with MSVC++, do the same as you would do with
649
the static libraries, as described above. But in Step 4,
650
you should only need to add the directory where the LIB files are installed
651
(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
652
installed in the @file{bin} directory. And instead of adding @file{libxx.a}
653
files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
654
@file{avutil.lib}. There should be no need for @file{libmingwex.a},
655
@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
656
statically linked into the DLLs. The @file{bin} directory contains a bunch
657
of DLL files, but the ones that are actually used to run your application
658
are the ones with a major version number in their filenames
659
(i.e. @file{avcodec-51.dll}).
660

    
661
@subsection Cross compilation for Windows with Linux
662

    
663
You must use the MinGW cross compilation tools available at
664
@url{http://www.mingw.org/}.
665

    
666
Then configure FFmpeg with the following options:
667
@example
668
./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
669
@end example
670
(you can change the cross-prefix according to the prefix chosen for the
671
MinGW tools).
672

    
673
Then you can easily test FFmpeg with Wine
674
(@url{http://www.winehq.com/}).
675

    
676
@subsection Compilation under Cygwin
677

    
678
The main issue with the 1.5.x Cygwin versions is that newlib, its C library,
679
does not contain llrint().  You need to upgrade to the unstable 1.7.x versions,
680
or leverage the implementation in MinGW (as explained below).
681

    
682
Just install your Cygwin with all the "Base" packages, plus the
683
following "Devel" ones:
684
@example
685
binutils, gcc-core, make, subversion, mingw-runtime, diffutils
686
@end example
687

    
688
The experimental gcc4 package is still buggy, hence please
689
use the official gcc 3.4.4 or a 4.2.x compiled from source by yourself.
690

    
691
Install the current binutils-20080624-2 as they work fine (the old
692
binutils-20060709-1 proved buggy on shared builds).
693

    
694
Then create a small library that just contains llrint():
695

    
696
@example
697
ar x /usr/lib/mingw/libmingwex.a llrint.o
698
ar cq /usr/local/lib/libllrint.a llrint.o
699
@end example
700

    
701
Then run
702

    
703
@example
704
./configure --enable-static --disable-shared  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
705
@end example
706

    
707
to make a static build or
708

    
709
@example
710
./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
711
@end example
712

    
713
to build shared libraries.
714

    
715
If you want to build FFmpeg with additional libraries, download Cygwin
716
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository:
717
@example
718
libogg-devel, libvorbis-devel
719
@end example
720

    
721
These library packages are only available from Cygwin Ports
722
(@url{http://sourceware.org/cygwinports/}) :
723

    
724
@example
725
yasm, libSDL-devel, libdirac-devel, libfaac-devel, libfaad-devel, libgsm-devel,
726
libmp3lame-devel, libschroedinger1.0-devel, speex-devel, libtheora-devel,
727
libxvidcore-devel
728
@end example
729

    
730
The recommendation for libnut and x264 is to build them from source by
731
yourself, as they evolve too quickly for Cygwin Ports to be up to date.
732

    
733
Cygwin 1.7.x has IPv6 support. You can add IPv6 to Cygwin 1.5.x by means
734
of the @code{libgetaddrinfo-devel} package, available at Cygwin Ports.
735

    
736
@subsection Crosscompilation for Windows under Cygwin
737

    
738
With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
739

    
740
Just install your Cygwin as explained before, plus these additional
741
"Devel" packages:
742
@example
743
gcc-mingw-core, mingw-runtime, mingw-zlib
744
@end example
745

    
746
and add some special flags to your configure invocation.
747

    
748
For a static build run
749
@example
750
./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
751
@end example
752

    
753
and for a build with shared libraries
754
@example
755
./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
756
@end example
757

    
758
@section BeOS
759

    
760
BeOS support is broken in mysterious ways.
761

    
762
@section OS/2
763

    
764
For information about compiling FFmpeg on OS/2 see
765
@url{http://www.edm2.com/index.php/FFmpeg}.
766

    
767
@chapter Developers Guide
768

    
769
@section API
770
@itemize @bullet
771
@item libavcodec is the library containing the codecs (both encoding and
772
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
773

    
774
@item libavformat is the library containing the file format handling (mux and
775
demux code for several formats). Look at @file{ffplay.c} to use it in a
776
player. See @file{output_example.c} to use it to generate audio or video
777
streams.
778

    
779
@end itemize
780

    
781
@section Integrating libavcodec or libavformat in your program
782

    
783
You can integrate all the source code of the libraries to link them
784
statically to avoid any version problem. All you need is to provide a
785
'config.mak' and a 'config.h' in the parent directory. See the defines
786
generated by ./configure to understand what is needed.
787

    
788
You can use libavcodec or libavformat in your commercial program, but
789
@emph{any patch you make must be published}. The best way to proceed is
790
to send your patches to the FFmpeg mailing list.
791

    
792
@node Coding Rules
793
@section Coding Rules
794

    
795
FFmpeg is programmed in the ISO C90 language with a few additional
796
features from ISO C99, namely:
797
@itemize @bullet
798
@item
799
the @samp{inline} keyword;
800
@item
801
@samp{//} comments;
802
@item
803
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
804
@item
805
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
806
@end itemize
807

    
808
These features are supported by all compilers we care about, so we will not
809
accept patches to remove their use unless they absolutely do not impair
810
clarity and performance.
811

    
812
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
813
compiles with several other compilers, such as the Compaq ccc compiler
814
or Sun Studio 9, and we would like to keep it that way unless it would
815
be exceedingly involved. To ensure compatibility, please do not use any
816
additional C99 features or GCC extensions. Especially watch out for:
817
@itemize @bullet
818
@item
819
mixing statements and declarations;
820
@item
821
@samp{long long} (use @samp{int64_t} instead);
822
@item
823
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
824
@item
825
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
826
@end itemize
827

    
828
Indent size is 4.
829
The presentation is the one specified by 'indent -i4 -kr -nut'.
830
The TAB character is forbidden outside of Makefiles as is any
831
form of trailing whitespace. Commits containing either will be
832
rejected by the Subversion repository.
833

    
834
The main priority in FFmpeg is simplicity and small code size in order to
835
minimize the bug count.
836

    
837
Comments: Use the JavaDoc/Doxygen
838
format (see examples below) so that code documentation
839
can be generated automatically. All nontrivial functions should have a comment
840
above them explaining what the function does, even if it is just one sentence.
841
All structures and their member variables should be documented, too.
842
@example
843
/**
844
 * @@file mpeg.c
845
 * MPEG codec.
846
 * @@author ...
847
 */
848

    
849
/**
850
 * Summary sentence.
851
 * more text ...
852
 * ...
853
 */
854
typedef struct Foobar@{
855
    int var1; /**< var1 description */
856
    int var2; ///< var2 description
857
    /** var3 description */
858
    int var3;
859
@} Foobar;
860

    
861
/**
862
 * Summary sentence.
863
 * more text ...
864
 * ...
865
 * @@param my_parameter description of my_parameter
866
 * @@return return value description
867
 */
868
int myfunc(int my_parameter)
869
...
870
@end example
871

    
872
fprintf and printf are forbidden in libavformat and libavcodec,
873
please use av_log() instead.
874

    
875
Casts should be used only when necessary. Unneeded parentheses
876
should also be avoided if they don't make the code easier to understand.
877

    
878
@section Development Policy
879

    
880
@enumerate
881
@item
882
   Contributions should be licensed under the LGPL 2.1, including an
883
   "or any later version" clause, or the MIT license.  GPL 2 including
884
   an "or any later version" clause is also acceptable, but LGPL is
885
   preferred.
886
@item
887
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
888
   enabled code which breaks compilation or compiles but does not work or
889
   breaks the regression tests)
890
   You can commit unfinished stuff (for testing etc), but it must be disabled
891
   (#ifdef etc) by default so it does not interfere with other developers'
892
   work.
893
@item
894
   You do not have to over-test things. If it works for you, and you think it
895
   should work for others, then commit. If your code has problems
896
   (portability, triggers compiler bugs, unusual environment etc) they will be
897
   reported and eventually fixed.
898
@item
899
   Do not commit unrelated changes together, split them into self-contained
900
   pieces. Also do not forget that if part B depends on part A, but A does not
901
   depend on B, then A can and should be committed first and separate from B.
902
   Keeping changes well split into self-contained parts makes reviewing and
903
   understanding them on the commit log mailing list easier. This also helps
904
   in case of debugging later on.
905
   Also if you have doubts about splitting or not splitting, do not hesitate to
906
   ask/discuss it on the developer mailing list.
907
@item
908
   Do not change behavior of the program (renaming options etc) without
909
   first discussing it on the ffmpeg-devel mailing list. Do not remove
910
   functionality from the code. Just improve!
911

    
912
   Note: Redundant code can be removed.
913
@item
914
   Do not commit changes to the build system (Makefiles, configure script)
915
   which change behavior, defaults etc, without asking first. The same
916
   applies to compiler warning fixes, trivial looking fixes and to code
917
   maintained by other developers. We usually have a reason for doing things
918
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
919
   list, and if the code maintainers say OK, you may commit. This does not
920
   apply to files you wrote and/or maintain.
921
@item
922
   We refuse source indentation and other cosmetic changes if they are mixed
923
   with functional changes, such commits will be rejected and removed. Every
924
   developer has his own indentation style, you should not change it. Of course
925
   if you (re)write something, you can use your own style, even though we would
926
   prefer if the indentation throughout FFmpeg was consistent (Many projects
927
   force a given indentation style - we do not.). If you really need to make
928
   indentation changes (try to avoid this), separate them strictly from real
929
   changes.
930

    
931
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
932
   then either do NOT change the indentation of the inner part within (do not
933
   move it to the right)! or do so in a separate commit
934
@item
935
   Always fill out the commit log message. Describe in a few lines what you
936
   changed and why. You can refer to mailing list postings if you fix a
937
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
938
@item
939
   If you apply a patch by someone else, include the name and email address in
940
   the log message. Since the ffmpeg-cvslog mailing list is publicly
941
   archived you should add some SPAM protection to the email address. Send an
942
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
943
   you applied the patch.
944
@item
945
   When applying patches that have been discussed (at length) on the mailing
946
   list, reference the thread in the log message.
947
@item
948
    Do NOT commit to code actively maintained by others without permission.
949
    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
950
    timeframe (12h for build failures and security fixes, 3 days small changes,
951
    1 week for big patches) then commit your patch if you think it is OK.
952
    Also note, the maintainer can simply ask for more time to review!
953
@item
954
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
955
    are sent there and reviewed by all the other developers. Bugs and possible
956
    improvements or general questions regarding commits are discussed there. We
957
    expect you to react if problems with your code are uncovered.
958
@item
959
    Update the documentation if you change behavior or add features. If you are
960
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
961
    maintainer(s) will review and commit your stuff.
962
@item
963
    Try to keep important discussions and requests (also) on the public
964
    developer mailing list, so that all developers can benefit from them.
965
@item
966
    Never write to unallocated memory, never write over the end of arrays,
967
    always check values read from some untrusted source before using them
968
    as array index or other risky things.
969
@item
970
    Remember to check if you need to bump versions for the specific libav
971
    parts (libavutil, libavcodec, libavformat) you are changing. You need
972
    to change the version integer.
973
    Incrementing the first component means no backward compatibility to
974
    previous versions (e.g. removal of a function from the public API).
975
    Incrementing the second component means backward compatible change
976
    (e.g. addition of a function to the public API or extension of an
977
    existing data structure).
978
    Incrementing the third component means a noteworthy binary compatible
979
    change (e.g. encoder bug fix that matters for the decoder).
980
@item
981
    Compiler warnings indicate potential bugs or code with bad style. If a type of
982
    warning always points to correct and clean code, that warning should
983
    be disabled, not the code changed.
984
    Thus the remaining warnings can either be bugs or correct code.
985
    If it is a bug, the bug has to be fixed. If it is not, the code should
986
    be changed to not generate a warning unless that causes a slowdown
987
    or obfuscates the code.
988
@item
989
    If you add a new file, give it a proper license header. Do not copy and
990
    paste it from a random place, use an existing file as template.
991
@end enumerate
992

    
993
We think our rules are not too hard. If you have comments, contact us.
994

    
995
Note, these rules are mostly borrowed from the MPlayer project.
996

    
997
@section Submitting patches
998

    
999
First, (@pxref{Coding Rules}) above if you did not yet.
1000

    
1001
When you submit your patch, try to send a unified diff (diff '-up'
1002
option). We cannot read other diffs :-)
1003

    
1004
Also please do not submit a patch which contains several unrelated changes.
1005
Split it into separate, self-contained pieces. This does not mean splitting
1006
file by file. Instead, make the patch as small as possible while still
1007
keeping it as a logical unit that contains an individual change, even
1008
if it spans multiple files. This makes reviewing your patches much easier
1009
for us and greatly increases your chances of getting your patch applied.
1010

    
1011
Run the regression tests before submitting a patch so that you can
1012
verify that there are no big problems.
1013

    
1014
Patches should be posted as base64 encoded attachments (or any other
1015
encoding which ensures that the patch will not be trashed during
1016
transmission) to the ffmpeg-devel mailing list, see
1017
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1018

    
1019
It also helps quite a bit if you tell us what the patch does (for example
1020
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1021
and has no lrint()')
1022

    
1023
Also please if you send several patches, send each patch as a separate mail,
1024
do not attach several unrelated patches to the same mail.
1025

    
1026
@section New codecs or formats checklist
1027

    
1028
@enumerate
1029
@item
1030
    Did you use av_cold for codec initialization and close functions?
1031
@item
1032
    Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
1033
    AVInputFormat/AVOutputFormat struct?
1034
@item
1035
    Did you bump the minor version number in @file{avcodec.h} or
1036
    @file{avformat.h}?
1037
@item
1038
    Did you register it in @file{allcodecs.c} or @file{allformats.c}?
1039
@item
1040
    Did you add the CodecID to @file{avcodec.h}?
1041
@item
1042
    If it has a fourcc, did you add it to @file{libavformat/riff.c},
1043
    even if it is only a decoder?
1044
@item
1045
    Did you add a rule to compile the appropriate files in the Makefile?
1046
    Remember to do this even if you're just adding a format to a file that is
1047
    already being compiled by some other rule, like a raw demuxer.
1048
@item
1049
    Did you add an entry to the table of supported formats or codecs in the
1050
    documentation?
1051
@item
1052
    Did you add an entry in the Changelog?
1053
@item
1054
    If it depends on a parser or a library, did you add that dependency in
1055
    configure?
1056
@item
1057
    Did you "svn add" the appropriate files before commiting?
1058
@end enumerate
1059

    
1060
@section patch submission checklist
1061

    
1062
@enumerate
1063
@item
1064
    Do the regression tests pass with the patch applied?
1065
@item
1066
    Does @code{make checkheaders} pass with the patch applied?
1067
@item
1068
    Is the patch a unified diff?
1069
@item
1070
    Is the patch against latest FFmpeg SVN?
1071
@item
1072
    Are you subscribed to ffmpeg-dev?
1073
    (the list is subscribers only due to spam)
1074
@item
1075
    Have you checked that the changes are minimal, so that the same cannot be
1076
    achieved with a smaller patch and/or simpler final code?
1077
@item
1078
    If the change is to speed critical code, did you benchmark it?
1079
@item
1080
    If you did any benchmarks, did you provide them in the mail?
1081
@item
1082
    Have you checked that the patch does not introduce buffer overflows or
1083
    other security issues?
1084
@item
1085
    Did you test your decoder or demuxer against damaged data? If no, see
1086
    tools/trasher and the noise bitstream filter. Your decoder or demuxer
1087
    should not crash or end in a (near) infinite loop when fed damaged data.
1088
@item
1089
    Is the patch created from the root of the source tree, so it can be
1090
    applied with @code{patch -p0}?
1091
@item
1092
    Does the patch not mix functional and cosmetic changes?
1093
@item
1094
    Did you add tabs or trailing whitespace to the code? Both are forbidden.
1095
@item
1096
    Is the patch attached to the email you send?
1097
@item
1098
    Is the mime type of the patch correct? It should be text/x-diff or
1099
    text/x-patch or at least text/plain and not application/octet-stream.
1100
@item
1101
    If the patch fixes a bug, did you provide a verbose analysis of the bug?
1102
@item
1103
    If the patch fixes a bug, did you provide enough information, including
1104
    a sample, so the bug can be reproduced and the fix can be verified?
1105
    Note please do not attach samples >100k to mails but rather provide a
1106
    URL, you can upload to ftp://upload.ffmpeg.org
1107
@item
1108
    Did you provide a verbose summary about what the patch does change?
1109
@item
1110
    Did you provide a verbose explanation why it changes things like it does?
1111
@item
1112
    Did you provide a verbose summary of the user visible advantages and
1113
    disadvantages if the patch is applied?
1114
@item
1115
    Did you provide an example so we can verify the new feature added by the
1116
    patch easily?
1117
@item
1118
    If you added a new file, did you insert a license header? It should be
1119
    taken from FFmpeg, not randomly copied and pasted from somewhere else.
1120
@item
1121
    You should maintain alphabetical order in alphabetically ordered lists as
1122
    long as doing so does not break API/ABI compatibility.
1123
@item
1124
    Lines with similar content should be aligned vertically when doing so
1125
    improves readability.
1126
@item
1127
    Did you provide a suggestion for a clear commit log message?
1128
@end enumerate
1129

    
1130
@section Patch review process
1131

    
1132
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1133
clear note that the patch is not for SVN.
1134
Reviews and comments will be posted as replies to the patch on the
1135
mailing list. The patch submitter then has to take care of every comment,
1136
that can be by resubmitting a changed patch or by discussion. Resubmitted
1137
patches will themselves be reviewed like any other patch. If at some point
1138
a patch passes review with no comments then it is approved, that can for
1139
simple and small patches happen immediately while large patches will generally
1140
have to be changed and reviewed many times before they are approved.
1141
After a patch is approved it will be committed to the repository.
1142

    
1143
We will review all submitted patches, but sometimes we are quite busy so
1144
especially for large patches this can take several weeks.
1145

    
1146
When resubmitting patches, please do not make any significant changes
1147
not related to the comments received during review. Such patches will
1148
be rejected. Instead, submit  significant changes or new features as
1149
separate patches.
1150

    
1151
@section Regression tests
1152

    
1153
Before submitting a patch (or committing to the repository), you should at least
1154
test that you did not break anything.
1155

    
1156
The regression tests build a synthetic video stream and a synthetic
1157
audio stream. These are then encoded and decoded with all codecs or
1158
formats. The CRC (or MD5) of each generated file is recorded in a
1159
result file. A 'diff' is launched to compare the reference results and
1160
the result file.
1161

    
1162
The regression tests then go on to test the FFserver code with a
1163
limited set of streams. It is important that this step runs correctly
1164
as well.
1165

    
1166
Run 'make test' to test all the codecs and formats.
1167

    
1168
Run 'make fulltest' to test all the codecs, formats and FFserver.
1169

    
1170
[Of course, some patches may change the results of the regression tests. In
1171
this case, the reference results of the regression tests shall be modified
1172
accordingly].
1173

    
1174
@bye