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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 Supported File Format @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 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   @tab X
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    @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
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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, mu-law/A-law @tab X  @tab  X
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@item raw Shorten audio         @tab    @tab  X
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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 Supported Image Format @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 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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@section Video Codecs
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@multitable @columnfractions .4 .1 .1 .4
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@item Supported Codec @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  X  @tab  X
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    @tab Supported through the 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 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     @tab  X
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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 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  X  @tab  X
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    @tab still experimental
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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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@section Audio Codecs
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@multitable @columnfractions .4 .1 .1 .1 .7
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@item Supported Codec @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  X  @tab  X
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    @tab Supported through the external library libfaac/libfaad.
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@item AC-3                   @tab IX  @tab IX
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    @tab liba52 can be used alternatively for decoding.
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@item AMR-NB                 @tab  X  @tab  X
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    @tab Supported through an external library.
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@item AMR-WB                 @tab  X  @tab  X
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    @tab Supported through an external library.
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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 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 FLAC lossless audio    @tab  X  @tab  X
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@item G.726  ADPCM           @tab  X  @tab  X
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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 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 1/3   @tab  X  @tab IX
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    @tab MP3 encoding is supported through the 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     @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  X  @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 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{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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@chapter Platform Specific information
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@section BSD
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BSD make will not build FFmpeg, you need to install and use GNU Make
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(@file{gmake}).
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@section Windows
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To get help and instructions for building FFmpeg under Windows, check out
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the FFmpeg Windows Help Forum at
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@url{http://arrozcru.no-ip.org/ffmpeg/}.
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@subsection Native Windows compilation
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FFmpeg can be built to run natively on Windows using the MinGW tools. Install
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the current versions of MSYS and MinGW from @url{http://www.mingw.org/}. Also
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install the coreutils package, and update to the latest MSYS make (note: not
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mingw32-make). You can find detailed installation
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instructions in the download section and the FAQ.
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Within the MSYS shell, configure and make with:
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@example
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./configure --enable-memalign-hack
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make
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make install
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@end example
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This will install @file{ffmpeg.exe} along with many other development files
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to @file{/usr/local}. You may specify another install path using the
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@code{--prefix} option in @file{configure}.
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Notes:
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@itemize
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@item Use at least bash 3.1. Older versions are known to fail on the
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configure script.
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@item In order to compile vhooks, you must have a POSIX-compliant libdl in
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your MinGW system. Get dlfcn-win32 from
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@url{http://code.google.com/p/dlfcn-win32}.
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@item In order to compile FFplay, you must have the MinGW development library
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of SDL. Get it from @url{http://www.libsdl.org}.
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Edit the @file{bin/sdl-config} script so that it points to the correct prefix
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where SDL was installed. Verify that @file{sdl-config} can be launched from
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the MSYS command line.
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@item By using @code{./configure --enable-shared} when configuring FFmpeg,
480
you can build libavutil, libavcodec and libavformat as DLLs.
481

    
482
@end itemize
483

    
484
@subsection Microsoft Visual C++ compatibility
485

    
486
As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
487
want to use the libav* libraries in your own applications, you can still
488
compile those applications using MSVC++. But the libav* libraries you link
489
to @emph{must} be built with MinGW. However, you will not be able to debug
490
inside the libav* libraries, since MSVC++ does not recognize the debug
491
symbols generated by GCC.
492
We strongly recommend you to move over from MSVC++ to MinGW tools.
493

    
494
This description of how to use the FFmpeg libraries with MSVC++ is based on
495
Microsoft Visual C++ 2005 Express Edition. If you have a different version,
496
you might have to modify the procedures slightly.
497

    
498
@subsubsection Using static libraries
499

    
500
Assuming you have just built and installed FFmpeg in @file{/usr/local}.
501

    
502
@enumerate
503

    
504
@item Create a new console application ("File / New / Project") and then
505
select "Win32 Console Application". On the appropriate page of the
506
Application Wizard, uncheck the "Precompiled headers" option.
507

    
508
@item Write the source code for your application, or, for testing, just
509
copy the code from an existing sample application into the source file
510
that MSVC++ has already created for you. For example, you can copy
511
@file{output_example.c} from the FFmpeg distribution.
512

    
513
@item Open the "Project / Properties" dialog box. In the "Configuration"
514
combo box, select "All Configurations" so that the changes you make will
515
affect both debug and release builds. In the tree view on the left hand
516
side, select "C/C++ / General", then edit the "Additional Include
517
Directories" setting to contain the path where the FFmpeg includes were
518
installed (i.e. @file{c:\msys\1.0\local\include}).
519
Do not add MinGW's include directory here, or the include files will
520
conflict with MSVC's.
521

    
522
@item Still in the "Project / Properties" dialog box, select
523
"Linker / General" from the tree view and edit the
524
"Additional Library Directories" setting to contain the @file{lib}
525
directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
526
the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
527
and the directory where MinGW's GCC libs are installed
528
(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
529
"Linker / Input" from the tree view, and add the files @file{libavformat.a},
530
@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
531
@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
532
to the end of "Additional Dependencies".
533

    
534
@item Now, select "C/C++ / Code Generation" from the tree view. Select
535
"Debug" in the "Configuration" combo box. Make sure that "Runtime
536
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
537
the "Configuration" combo box and make sure that "Runtime Library" is
538
set to "Multi-threaded DLL".
539

    
540
@item Click "OK" to close the "Project / Properties" dialog box.
541

    
542
@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
543
Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
544
and install it in MSVC++'s include directory
545
(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
546

    
547
@item MSVC++ also does not understand the @code{inline} keyword used by
548
FFmpeg, so you must add this line before @code{#include}ing libav*:
549
@example
550
#define inline _inline
551
@end example
552

    
553
@item Build your application, everything should work.
554

    
555
@end enumerate
556

    
557
@subsubsection Using shared libraries
558

    
559
This is how to create DLL and LIB files that are compatible with MSVC++:
560

    
561
@enumerate
562

    
563
@item Add a call to @file{vcvars32.bat} (which sets up the environment
564
variables for the Visual C++ tools) as the first line of @file{msys.bat}.
565
The standard location for @file{vcvars32.bat} is
566
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
567
and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
568
If this corresponds to your setup, add the following line as the first line
569
of @file{msys.bat}:
570

    
571
@example
572
call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
573
@end example
574

    
575
Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
576
and run @file{c:\msys\1.0\msys.bat} from there.
577

    
578
@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
579
from @file{Microsoft (R) Library Manager}, this means your environment
580
variables are set up correctly, the @file{Microsoft (R) Library Manager}
581
is on the path and will be used by FFmpeg to create
582
MSVC++-compatible import libraries.
583

    
584
@item Build FFmpeg with
585

    
586
@example
587
./configure --enable-shared --enable-memalign-hack
588
make
589
make install
590
@end example
591

    
592
Your install path (@file{/usr/local/} by default) should now have the
593
necessary DLL and LIB files under the @file{bin} directory.
594

    
595
@end enumerate
596

    
597
To use those files with MSVC++, do the same as you would do with
598
the static libraries, as described above. But in Step 4,
599
you should only need to add the directory where the LIB files are installed
600
(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
601
installed in the @file{bin} directory. And instead of adding @file{libxx.a}
602
files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
603
@file{avutil.lib}. There should be no need for @file{libmingwex.a},
604
@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
605
statically linked into the DLLs. The @file{bin} directory contains a bunch
606
of DLL files, but the ones that are actually used to run your application
607
are the ones with a major version number in their filenames
608
(i.e. @file{avcodec-51.dll}).
609

    
610
@subsection Cross compilation for Windows with Linux
611

    
612
You must use the MinGW cross compilation tools available at
613
@url{http://www.mingw.org/}.
614

    
615
Then configure FFmpeg with the following options:
616
@example
617
./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
618
@end example
619
(you can change the cross-prefix according to the prefix chosen for the
620
MinGW tools).
621

    
622
Then you can easily test FFmpeg with Wine
623
(@url{http://www.winehq.com/}).
624

    
625
@subsection Compilation under Cygwin
626

    
627
The main issue with Cygwin is that newlib, its C library, does not
628
contain llrint().  However, it is possible to leverage the
629
implementation in MinGW.
630

    
631
Just install your Cygwin with all the "Base" packages, plus the
632
following "Devel" ones:
633
@example
634
binutils, gcc-core, make, subversion, mingw-runtime
635
@end example
636

    
637
Do not install binutils-20060709-1 (they are buggy on shared builds);
638
use binutils-20050610-1 instead.
639

    
640
Then create a small library that just contains llrint():
641

    
642
@example
643
ar x /usr/lib/mingw/libmingwex.a llrint.o
644
ar cq /usr/local/lib/libllrint.a llrint.o
645
@end example
646

    
647
Then run
648

    
649
@example
650
./configure --enable-static --disable-shared  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
651
@end example
652

    
653
to make a static build or
654

    
655
@example
656
./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
657
@end example
658

    
659
to build shared libraries.
660

    
661
If you want to build FFmpeg with additional libraries, download Cygwin
662
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
663
and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
664
(@url{http://cygwinports.dotsrc.org/}).
665

    
666
@subsection Crosscompilation for Windows under Cygwin
667

    
668
With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
669

    
670
Just install your Cygwin as explained before, plus these additional
671
"Devel" packages:
672
@example
673
gcc-mingw-core, mingw-runtime, mingw-zlib
674
@end example
675

    
676
and add some special flags to your configure invocation.
677

    
678
For a static build run
679
@example
680
./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
681
@end example
682

    
683
and for a build with shared libraries
684
@example
685
./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
686
@end example
687

    
688
@section BeOS
689

    
690
BeOS support is broken in mysterious ways.
691

    
692
@section OS/2
693

    
694
For information about compiling FFmpeg on OS/2 see
695
@url{http://www.edm2.com/index.php/FFmpeg}.
696

    
697
@chapter Developers Guide
698

    
699
@section API
700
@itemize @bullet
701
@item libavcodec is the library containing the codecs (both encoding and
702
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
703

    
704
@item libavformat is the library containing the file format handling (mux and
705
demux code for several formats). Look at @file{ffplay.c} to use it in a
706
player. See @file{output_example.c} to use it to generate audio or video
707
streams.
708

    
709
@end itemize
710

    
711
@section Integrating libavcodec or libavformat in your program
712

    
713
You can integrate all the source code of the libraries to link them
714
statically to avoid any version problem. All you need is to provide a
715
'config.mak' and a 'config.h' in the parent directory. See the defines
716
generated by ./configure to understand what is needed.
717

    
718
You can use libavcodec or libavformat in your commercial program, but
719
@emph{any patch you make must be published}. The best way to proceed is
720
to send your patches to the FFmpeg mailing list.
721

    
722
@node Coding Rules
723
@section Coding Rules
724

    
725
FFmpeg is programmed in the ISO C90 language with a few additional
726
features from ISO C99, namely:
727
@itemize @bullet
728
@item
729
the @samp{inline} keyword;
730
@item
731
@samp{//} comments;
732
@item
733
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
734
@item
735
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
736
@end itemize
737

    
738
These features are supported by all compilers we care about, so we will not
739
accept patches to remove their use unless they absolutely do not impair
740
clarity and performance.
741

    
742
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
743
compiles with several other compilers, such as the Compaq ccc compiler
744
or Sun Studio 9, and we would like to keep it that way unless it would
745
be exceedingly involved. To ensure compatibility, please do not use any
746
additional C99 features or GCC extensions. Especially watch out for:
747
@itemize @bullet
748
@item
749
mixing statements and declarations;
750
@item
751
@samp{long long} (use @samp{int64_t} instead);
752
@item
753
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
754
@item
755
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
756
@end itemize
757

    
758
Indent size is 4.
759
The presentation is the one specified by 'indent -i4 -kr -nut'.
760
The TAB character is forbidden outside of Makefiles as is any
761
form of trailing whitespace. Commits containing either will be
762
rejected by the Subversion repository.
763

    
764
The main priority in FFmpeg is simplicity and small code size in order to
765
minimize the bug count.
766

    
767
Comments: Use the JavaDoc/Doxygen
768
format (see examples below) so that code documentation
769
can be generated automatically. All nontrivial functions should have a comment
770
above them explaining what the function does, even if it is just one sentence.
771
All structures and their member variables should be documented, too.
772
@example
773
/**
774
 * @@file mpeg.c
775
 * MPEG codec.
776
 * @@author ...
777
 */
778

    
779
/**
780
 * Summary sentence.
781
 * more text ...
782
 * ...
783
 */
784
typedef struct Foobar@{
785
    int var1; /**< var1 description */
786
    int var2; ///< var2 description
787
    /** var3 description */
788
    int var3;
789
@} Foobar;
790

    
791
/**
792
 * Summary sentence.
793
 * more text ...
794
 * ...
795
 * @@param my_parameter description of my_parameter
796
 * @@return return value description
797
 */
798
int myfunc(int my_parameter)
799
...
800
@end example
801

    
802
fprintf and printf are forbidden in libavformat and libavcodec,
803
please use av_log() instead.
804

    
805
Casts should be used only when necessary. Unneeded parentheses
806
should also be avoided if they don't make the code easier to understand.
807

    
808
@section Development Policy
809

    
810
@enumerate
811
@item
812
   Contributions should be licensed under the LGPL 2.1, including an
813
   "or any later version" clause, or the MIT license.  GPL 2 including
814
   an "or any later version" clause is also acceptable, but LGPL is
815
   preferred.
816
@item
817
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
818
   enabled code which breaks compilation or compiles but does not work or
819
   breaks the regression tests)
820
   You can commit unfinished stuff (for testing etc), but it must be disabled
821
   (#ifdef etc) by default so it does not interfere with other developers'
822
   work.
823
@item
824
   You do not have to over-test things. If it works for you, and you think it
825
   should work for others, then commit. If your code has problems
826
   (portability, triggers compiler bugs, unusual environment etc) they will be
827
   reported and eventually fixed.
828
@item
829
   Do not commit unrelated changes together, split them into self-contained
830
   pieces. Also do not forget that if part B depends on part A, but A does not
831
   depend on B, then A can and should be committed first and separate from B.
832
   Keeping changes well split into self-contained parts makes reviewing and
833
   understanding them on the commit log mailing list easier. This also helps
834
   in case of debugging later on.
835
   Also if you have doubts about splitting or not splitting, do not hesitate to
836
   ask/discuss it on the developer mailing list.
837
@item
838
   Do not change behavior of the program (renaming options etc) without
839
   first discussing it on the ffmpeg-devel mailing list. Do not remove
840
   functionality from the code. Just improve!
841

    
842
   Note: Redundant code can be removed.
843
@item
844
   Do not commit changes to the build system (Makefiles, configure script)
845
   which change behavior, defaults etc, without asking first. The same
846
   applies to compiler warning fixes, trivial looking fixes and to code
847
   maintained by other developers. We usually have a reason for doing things
848
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
849
   list, and if the code maintainers say OK, you may commit. This does not
850
   apply to files you wrote and/or maintain.
851
@item
852
   We refuse source indentation and other cosmetic changes if they are mixed
853
   with functional changes, such commits will be rejected and removed. Every
854
   developer has his own indentation style, you should not change it. Of course
855
   if you (re)write something, you can use your own style, even though we would
856
   prefer if the indentation throughout FFmpeg was consistent (Many projects
857
   force a given indentation style - we do not.). If you really need to make
858
   indentation changes (try to avoid this), separate them strictly from real
859
   changes.
860

    
861
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
862
   then either do NOT change the indentation of the inner part within (do not
863
   move it to the right)! or do so in a separate commit
864
@item
865
   Always fill out the commit log message. Describe in a few lines what you
866
   changed and why. You can refer to mailing list postings if you fix a
867
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
868
@item
869
   If you apply a patch by someone else, include the name and email address in
870
   the log message. Since the ffmpeg-cvslog mailing list is publicly
871
   archived you should add some SPAM protection to the email address. Send an
872
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
873
   you applied the patch.
874
@item
875
   When applying patches that have been discussed (at length) on the mailing
876
   list, reference the thread in the log message.
877
@item
878
    Do NOT commit to code actively maintained by others without permission.
879
    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
880
    timeframe (12h for build failures and security fixes, 3 days small changes,
881
    1 week for big patches) then commit your patch if you think it is OK.
882
    Also note, the maintainer can simply ask for more time to review!
883
@item
884
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
885
    are sent there and reviewed by all the other developers. Bugs and possible
886
    improvements or general questions regarding commits are discussed there. We
887
    expect you to react if problems with your code are uncovered.
888
@item
889
    Update the documentation if you change behavior or add features. If you are
890
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
891
    maintainer(s) will review and commit your stuff.
892
@item
893
    Try to keep important discussions and requests (also) on the public
894
    developer mailing list, so that all developers can benefit from them.
895
@item
896
    Never write to unallocated memory, never write over the end of arrays,
897
    always check values read from some untrusted source before using them
898
    as array index or other risky things.
899
@item
900
    Remember to check if you need to bump versions for the specific libav
901
    parts (libavutil, libavcodec, libavformat) you are changing. You need
902
    to change the version integer.
903
    Incrementing the first component means no backward compatibility to
904
    previous versions (e.g. removal of a function from the public API).
905
    Incrementing the second component means backward compatible change
906
    (e.g. addition of a function to the public API or extension of an
907
    existing data structure).
908
    Incrementing the third component means a noteworthy binary compatible
909
    change (e.g. encoder bug fix that matters for the decoder).
910
@item
911
    Compiler warnings indicate potential bugs or code with bad style. If a type of
912
    warning always points to correct and clean code, that warning should
913
    be disabled, not the code changed.
914
    Thus the remaining warnings can either be bugs or correct code.
915
    If it is a bug, the bug has to be fixed. If it is not, the code should
916
    be changed to not generate a warning unless that causes a slowdown
917
    or obfuscates the code.
918
@item
919
    If you add a new file, give it a proper license header. Do not copy and
920
    paste it from a random place, use an existing file as template.
921
@end enumerate
922

    
923
We think our rules are not too hard. If you have comments, contact us.
924

    
925
Note, these rules are mostly borrowed from the MPlayer project.
926

    
927
@section Submitting patches
928

    
929
First, (@pxref{Coding Rules}) above if you did not yet.
930

    
931
When you submit your patch, try to send a unified diff (diff '-up'
932
option). We cannot read other diffs :-)
933

    
934
Also please do not submit a patch which contains several unrelated changes.
935
Split it into separate, self-contained pieces. This does not mean splitting
936
file by file. Instead, make the patch as small as possible while still
937
keeping it as a logical unit that contains an individual change, even
938
if it spans multiple files. This makes reviewing your patches much easier
939
for us and greatly increases your chances of getting your patch applied.
940

    
941
Run the regression tests before submitting a patch so that you can
942
verify that there are no big problems.
943

    
944
Patches should be posted as base64 encoded attachments (or any other
945
encoding which ensures that the patch will not be trashed during
946
transmission) to the ffmpeg-devel mailing list, see
947
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
948

    
949
It also helps quite a bit if you tell us what the patch does (for example
950
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
951
and has no lrint()')
952

    
953
Also please if you send several patches, send each patch as a separate mail,
954
do not attach several unrelated patches to the same mail.
955

    
956
@section New codecs or formats checklist
957

    
958
@enumerate
959
@item
960
    Did you use av_cold for codec initialization and close functions?
961
@item
962
    Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
963
    AVInputFormat/AVOutputFormat struct?
964
@item
965
    Did you bump the minor version number in @file{avcodec.h} or
966
    @file{avformat.h}?
967
@item
968
    Did you register it in @file{allcodecs.c} or @file{allformats.c}?
969
@item
970
    Did you add the CodecID to @file{avcodec.h}?
971
@item
972
    If it has a fourcc, did you add it to @file{libavformat/riff.c},
973
    even if it is only a decoder?
974
@item
975
    Did you add a rule to compile the appropriate files in the Makefile?
976
    Remember to do this even if you're just adding a format to a file that is
977
    already being compiled by some other rule, like a raw demuxer.
978
@item
979
    Did you add an entry to the table of supported formats or codecs in the
980
    documentation?
981
@item
982
    Did you add an entry in the Changelog?
983
@item
984
    If it depends on a parser or a library, did you add that dependency in
985
    configure?
986
@item
987
    Did you "svn add" the appropriate files before commiting?
988
@end enumerate
989

    
990
@section patch submission checklist
991

    
992
@enumerate
993
@item
994
    Do the regression tests pass with the patch applied?
995
@item
996
    Is the patch a unified diff?
997
@item
998
    Is the patch against latest FFmpeg SVN?
999
@item
1000
    Are you subscribed to ffmpeg-dev?
1001
    (the list is subscribers only due to spam)
1002
@item
1003
    Have you checked that the changes are minimal, so that the same cannot be
1004
    achieved with a smaller patch and/or simpler final code?
1005
@item
1006
    If the change is to speed critical code, did you benchmark it?
1007
@item
1008
    If you did any benchmarks, did you provide them in the mail?
1009
@item
1010
    Have you checked that the patch does not introduce buffer overflows or
1011
    other security issues?
1012
@item
1013
    If you add a new demuxer or decoder, have you checked that it does not
1014
    crash with damaged input (see tools/trasher)?
1015
@item
1016
    Is the patch created from the root of the source tree, so it can be
1017
    applied with @code{patch -p0}?
1018
@item
1019
    Does the patch not mix functional and cosmetic changes?
1020
@item
1021
    Did you add tabs or trailing whitespace to the code? Both are forbidden.
1022
@item
1023
    Is the patch attached to the email you send?
1024
@item
1025
    Is the mime type of the patch correct? It should be text/x-diff or
1026
    text/x-patch or at least text/plain and not application/octet-stream.
1027
@item
1028
    If the patch fixes a bug, did you provide a verbose analysis of the bug?
1029
@item
1030
    If the patch fixes a bug, did you provide enough information, including
1031
    a sample, so the bug can be reproduced and the fix can be verified?
1032
    Note please do not attach samples >100k to mails but rather provide a
1033
    URL, you can upload to ftp://upload.mplayerhq.hu
1034
@item
1035
    Did you provide a verbose summary about what the patch does change?
1036
@item
1037
    Did you provide a verbose explanation why it changes things like it does?
1038
@item
1039
    Did you provide a verbose summary of the user visible advantages and
1040
    disadvantages if the patch is applied?
1041
@item
1042
    Did you provide an example so we can verify the new feature added by the
1043
    patch easily?
1044
@item
1045
    If you added a new file, did you insert a license header? It should be
1046
    taken from FFmpeg, not randomly copied and pasted from somewhere else.
1047
@item
1048
    You should maintain alphabetical order in alphabetically ordered lists as
1049
    long as doing so does not break API/ABI compatibility.
1050
@item
1051
    Lines with similar content should be aligned vertically when doing so
1052
    improves readability.
1053
@item
1054
    Did you provide a suggestion for a clear commit log message?
1055
@item
1056
    Did you test your decoder or demuxer against damaged data? If no, see
1057
    tools/trasher and the noise bitstream filter. Your decoder or demuxer
1058
    should not crash or end in a (near) infinite loop when fed damaged data.
1059
@end enumerate
1060

    
1061
@section Patch review process
1062

    
1063
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1064
clear note that the patch is not for SVN.
1065
Reviews and comments will be posted as replies to the patch on the
1066
mailing list. The patch submitter then has to take care of every comment,
1067
that can be by resubmitting a changed patch or by discussion. Resubmitted
1068
patches will themselves be reviewed like any other patch. If at some point
1069
a patch passes review with no comments then it is approved, that can for
1070
simple and small patches happen immediately while large patches will generally
1071
have to be changed and reviewed many times before they are approved.
1072
After a patch is approved it will be committed to the repository.
1073

    
1074
We will review all submitted patches, but sometimes we are quite busy so
1075
especially for large patches this can take several weeks.
1076

    
1077
When resubmitting patches, please do not make any significant changes
1078
not related to the comments received during review. Such patches will
1079
be rejected. Instead, submit  significant changes or new features as
1080
separate patches.
1081

    
1082
@section Regression tests
1083

    
1084
Before submitting a patch (or committing to the repository), you should at least
1085
test that you did not break anything.
1086

    
1087
The regression tests build a synthetic video stream and a synthetic
1088
audio stream. These are then encoded and decoded with all codecs or
1089
formats. The CRC (or MD5) of each generated file is recorded in a
1090
result file. A 'diff' is launched to compare the reference results and
1091
the result file.
1092

    
1093
The regression tests then go on to test the FFserver code with a
1094
limited set of streams. It is important that this step runs correctly
1095
as well.
1096

    
1097
Run 'make test' to test all the codecs and formats.
1098

    
1099
Run 'make fulltest' to test all the codecs, formats and FFserver.
1100

    
1101
[Of course, some patches may change the results of the regression tests. In
1102
this case, the reference results of the regression tests shall be modified
1103
accordingly].
1104

    
1105
@bye