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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 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 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 BFI                       @tab   @tab X
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     @tab Brute Force & Ignorance, used in Flash Traffic: City of Angels.
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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                       @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 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 Creative VOC              @tab X @tab X
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     @tab Created for the Sound Blaster Pro.
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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 MAXIS EA XA               @tab   @tab X
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     @tab Used in Sim City 3000; file extension .xa.
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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 Matroska                  @tab X @tab X
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@item Monkey's Audio            @tab   @tab X
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@item MOV/QuickTime             @tab X @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 Nullsoft Video            @tab   @tab X
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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 PVA                       @tab   @tab X
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     @tab Used by TechnoTrend DVB PCI boards.
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@item PlayStation STR           @tab   @tab X
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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 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 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 RealMedia                 @tab X @tab X
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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 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 SUN AU format             @tab X @tab X
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@item Sega FILM/CPK             @tab   @tab X
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     @tab Used in many Sega Saturn console games.
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@item Sierra 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 Smacker                   @tab   @tab X
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     @tab Multimedia format used by many games.
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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 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 TIFF         @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
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@item Targa        @tab   @tab X @tab Targa (.TGA) image format
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@item .Y.U.V       @tab X @tab X @tab one raw file per component
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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 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 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 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     @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 FFmpeg Sonic           @tab  X  @tab  X
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     @tab experimental lossy/lossless 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,
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you can build libavutil, libavcodec and libavformat as DLLs.
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@end itemize
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@subsection Microsoft Visual C++ compatibility
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As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
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want to use the libav* libraries in your own applications, you can still
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compile those applications using MSVC++. But the libav* libraries you link
482
to @emph{must} be built with MinGW. However, you will not be able to debug
483
inside the libav* libraries, since MSVC++ does not recognize the debug
484
symbols generated by GCC.
485
We strongly recommend you to move over from MSVC++ to MinGW tools.
486

    
487
This description of how to use the FFmpeg libraries with MSVC++ is based on
488
Microsoft Visual C++ 2005 Express Edition. If you have a different version,
489
you might have to modify the procedures slightly.
490

    
491
@subsubsection Using static libraries
492

    
493
Assuming you have just built and installed FFmpeg in @file{/usr/local}.
494

    
495
@enumerate
496

    
497
@item Create a new console application ("File / New / Project") and then
498
select "Win32 Console Application". On the appropriate page of the
499
Application Wizard, uncheck the "Precompiled headers" option.
500

    
501
@item Write the source code for your application, or, for testing, just
502
copy the code from an existing sample application into the source file
503
that MSVC++ has already created for you. For example, you can copy
504
@file{output_example.c} from the FFmpeg distribution.
505

    
506
@item Open the "Project / Properties" dialog box. In the "Configuration"
507
combo box, select "All Configurations" so that the changes you make will
508
affect both debug and release builds. In the tree view on the left hand
509
side, select "C/C++ / General", then edit the "Additional Include
510
Directories" setting to contain the path where the FFmpeg includes were
511
installed (i.e. @file{c:\msys\1.0\local\include}).
512
Do not add MinGW's include directory here, or the include files will
513
conflict with MSVC's.
514

    
515
@item Still in the "Project / Properties" dialog box, select
516
"Linker / General" from the tree view and edit the
517
"Additional Library Directories" setting to contain the @file{lib}
518
directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
519
the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
520
and the directory where MinGW's GCC libs are installed
521
(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
522
"Linker / Input" from the tree view, and add the files @file{libavformat.a},
523
@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
524
@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
525
to the end of "Additional Dependencies".
526

    
527
@item Now, select "C/C++ / Code Generation" from the tree view. Select
528
"Debug" in the "Configuration" combo box. Make sure that "Runtime
529
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
530
the "Configuration" combo box and make sure that "Runtime Library" is
531
set to "Multi-threaded DLL".
532

    
533
@item Click "OK" to close the "Project / Properties" dialog box.
534

    
535
@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
536
Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
537
and install it in MSVC++'s include directory
538
(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
539

    
540
@item MSVC++ also does not understand the @code{inline} keyword used by
541
FFmpeg, so you must add this line before @code{#include}ing libav*:
542
@example
543
#define inline _inline
544
@end example
545

    
546
@item Build your application, everything should work.
547

    
548
@end enumerate
549

    
550
@subsubsection Using shared libraries
551

    
552
This is how to create DLL and LIB files that are compatible with MSVC++:
553

    
554
@enumerate
555

    
556
@item Add a call to @file{vcvars32.bat} (which sets up the environment
557
variables for the Visual C++ tools) as the first line of @file{msys.bat}.
558
The standard location for @file{vcvars32.bat} is
559
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
560
and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
561
If this corresponds to your setup, add the following line as the first line
562
of @file{msys.bat}:
563

    
564
@example
565
call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
566
@end example
567

    
568
Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
569
and run @file{c:\msys\1.0\msys.bat} from there.
570

    
571
@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
572
from @file{Microsoft (R) Library Manager}, this means your environment
573
variables are set up correctly, the @file{Microsoft (R) Library Manager}
574
is on the path and will be used by FFmpeg to create
575
MSVC++-compatible import libraries.
576

    
577
@item Build FFmpeg with
578

    
579
@example
580
./configure --enable-shared --enable-memalign-hack
581
make
582
make install
583
@end example
584

    
585
Your install path (@file{/usr/local/} by default) should now have the
586
necessary DLL and LIB files under the @file{bin} directory.
587

    
588
@end enumerate
589

    
590
To use those files with MSVC++, do the same as you would do with
591
the static libraries, as described above. But in Step 4,
592
you should only need to add the directory where the LIB files are installed
593
(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
594
installed in the @file{bin} directory. And instead of adding @file{libxx.a}
595
files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
596
@file{avutil.lib}. There should be no need for @file{libmingwex.a},
597
@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
598
statically linked into the DLLs. The @file{bin} directory contains a bunch
599
of DLL files, but the ones that are actually used to run your application
600
are the ones with a major version number in their filenames
601
(i.e. @file{avcodec-51.dll}).
602

    
603
@subsection Cross compilation for Windows with Linux
604

    
605
You must use the MinGW cross compilation tools available at
606
@url{http://www.mingw.org/}.
607

    
608
Then configure FFmpeg with the following options:
609
@example
610
./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
611
@end example
612
(you can change the cross-prefix according to the prefix chosen for the
613
MinGW tools).
614

    
615
Then you can easily test FFmpeg with Wine
616
(@url{http://www.winehq.com/}).
617

    
618
@subsection Compilation under Cygwin
619

    
620
The main issue with Cygwin is that newlib, its C library, does not
621
contain llrint().  However, it is possible to leverage the
622
implementation in MinGW.
623

    
624
Just install your Cygwin with all the "Base" packages, plus the
625
following "Devel" ones:
626
@example
627
binutils, gcc-core, make, subversion, mingw-runtime
628
@end example
629

    
630
Do not install binutils-20060709-1 (they are buggy on shared builds);
631
use binutils-20050610-1 instead.
632

    
633
Then create a small library that just contains llrint():
634

    
635
@example
636
ar x /usr/lib/mingw/libmingwex.a llrint.o
637
ar cq /usr/local/lib/libllrint.a llrint.o
638
@end example
639

    
640
Then run
641

    
642
@example
643
./configure --enable-static --disable-shared  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
644
@end example
645

    
646
to make a static build or
647

    
648
@example
649
./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
650
@end example
651

    
652
to build shared libraries.
653

    
654
If you want to build FFmpeg with additional libraries, download Cygwin
655
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
656
and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
657
(@url{http://cygwinports.dotsrc.org/}).
658

    
659
@subsection Crosscompilation for Windows under Cygwin
660

    
661
With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
662

    
663
Just install your Cygwin as explained before, plus these additional
664
"Devel" packages:
665
@example
666
gcc-mingw-core, mingw-runtime, mingw-zlib
667
@end example
668

    
669
and add some special flags to your configure invocation.
670

    
671
For a static build run
672
@example
673
./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
674
@end example
675

    
676
and for a build with shared libraries
677
@example
678
./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
679
@end example
680

    
681
@section BeOS
682

    
683
BeOS support is broken in mysterious ways.
684

    
685
@section OS/2
686

    
687
For information about compiling FFmpeg on OS/2 see
688
@url{http://www.edm2.com/index.php/FFmpeg}.
689

    
690
@chapter Developers Guide
691

    
692
@section API
693
@itemize @bullet
694
@item libavcodec is the library containing the codecs (both encoding and
695
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
696

    
697
@item libavformat is the library containing the file format handling (mux and
698
demux code for several formats). Look at @file{ffplay.c} to use it in a
699
player. See @file{output_example.c} to use it to generate audio or video
700
streams.
701

    
702
@end itemize
703

    
704
@section Integrating libavcodec or libavformat in your program
705

    
706
You can integrate all the source code of the libraries to link them
707
statically to avoid any version problem. All you need is to provide a
708
'config.mak' and a 'config.h' in the parent directory. See the defines
709
generated by ./configure to understand what is needed.
710

    
711
You can use libavcodec or libavformat in your commercial program, but
712
@emph{any patch you make must be published}. The best way to proceed is
713
to send your patches to the FFmpeg mailing list.
714

    
715
@node Coding Rules
716
@section Coding Rules
717

    
718
FFmpeg is programmed in the ISO C90 language with a few additional
719
features from ISO C99, namely:
720
@itemize @bullet
721
@item
722
the @samp{inline} keyword;
723
@item
724
@samp{//} comments;
725
@item
726
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
727
@item
728
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
729
@end itemize
730

    
731
These features are supported by all compilers we care about, so we will not
732
accept patches to remove their use unless they absolutely do not impair
733
clarity and performance.
734

    
735
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
736
compiles with several other compilers, such as the Compaq ccc compiler
737
or Sun Studio 9, and we would like to keep it that way unless it would
738
be exceedingly involved. To ensure compatibility, please do not use any
739
additional C99 features or GCC extensions. Especially watch out for:
740
@itemize @bullet
741
@item
742
mixing statements and declarations;
743
@item
744
@samp{long long} (use @samp{int64_t} instead);
745
@item
746
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
747
@item
748
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
749
@end itemize
750

    
751
Indent size is 4.
752
The presentation is the one specified by 'indent -i4 -kr -nut'.
753
The TAB character is forbidden outside of Makefiles as is any
754
form of trailing whitespace. Commits containing either will be
755
rejected by the Subversion repository.
756

    
757
The main priority in FFmpeg is simplicity and small code size in order to
758
minimize the bug count.
759

    
760
Comments: Use the JavaDoc/Doxygen
761
format (see examples below) so that code documentation
762
can be generated automatically. All nontrivial functions should have a comment
763
above them explaining what the function does, even if it is just one sentence.
764
All structures and their member variables should be documented, too.
765
@example
766
/**
767
 * @@file mpeg.c
768
 * MPEG codec.
769
 * @@author ...
770
 */
771

    
772
/**
773
 * Summary sentence.
774
 * more text ...
775
 * ...
776
 */
777
typedef struct Foobar@{
778
    int var1; /**< var1 description */
779
    int var2; ///< var2 description
780
    /** var3 description */
781
    int var3;
782
@} Foobar;
783

    
784
/**
785
 * Summary sentence.
786
 * more text ...
787
 * ...
788
 * @@param my_parameter description of my_parameter
789
 * @@return return value description
790
 */
791
int myfunc(int my_parameter)
792
...
793
@end example
794

    
795
fprintf and printf are forbidden in libavformat and libavcodec,
796
please use av_log() instead.
797

    
798
Casts should be used only when necessary. Unneeded parentheses
799
should also be avoided if they don't make the code easier to understand.
800

    
801
@section Development Policy
802

    
803
@enumerate
804
@item
805
   Contributions should be licensed under the LGPL 2.1, including an
806
   "or any later version" clause, or the MIT license.  GPL 2 including
807
   an "or any later version" clause is also acceptable, but LGPL is
808
   preferred.
809
@item
810
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
811
   enabled code which breaks compilation or compiles but does not work or
812
   breaks the regression tests)
813
   You can commit unfinished stuff (for testing etc), but it must be disabled
814
   (#ifdef etc) by default so it does not interfere with other developers'
815
   work.
816
@item
817
   You do not have to over-test things. If it works for you, and you think it
818
   should work for others, then commit. If your code has problems
819
   (portability, triggers compiler bugs, unusual environment etc) they will be
820
   reported and eventually fixed.
821
@item
822
   Do not commit unrelated changes together, split them into self-contained
823
   pieces. Also do not forget that if part B depends on part A, but A does not
824
   depend on B, then A can and should be committed first and separate from B.
825
   Keeping changes well split into self-contained parts makes reviewing and
826
   understanding them on the commit log mailing list easier. This also helps
827
   in case of debugging later on.
828
   Also if you have doubts about splitting or not splitting, do not hesitate to
829
   ask/discuss it on the developer mailing list.
830
@item
831
   Do not change behavior of the program (renaming options etc) without
832
   first discussing it on the ffmpeg-devel mailing list. Do not remove
833
   functionality from the code. Just improve!
834

    
835
   Note: Redundant code can be removed.
836
@item
837
   Do not commit changes to the build system (Makefiles, configure script)
838
   which change behavior, defaults etc, without asking first. The same
839
   applies to compiler warning fixes, trivial looking fixes and to code
840
   maintained by other developers. We usually have a reason for doing things
841
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
842
   list, and if the code maintainers say OK, you may commit. This does not
843
   apply to files you wrote and/or maintain.
844
@item
845
   We refuse source indentation and other cosmetic changes if they are mixed
846
   with functional changes, such commits will be rejected and removed. Every
847
   developer has his own indentation style, you should not change it. Of course
848
   if you (re)write something, you can use your own style, even though we would
849
   prefer if the indentation throughout FFmpeg was consistent (Many projects
850
   force a given indentation style - we do not.). If you really need to make
851
   indentation changes (try to avoid this), separate them strictly from real
852
   changes.
853

    
854
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
855
   then either do NOT change the indentation of the inner part within (do not
856
   move it to the right)! or do so in a separate commit
857
@item
858
   Always fill out the commit log message. Describe in a few lines what you
859
   changed and why. You can refer to mailing list postings if you fix a
860
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
861
@item
862
   If you apply a patch by someone else, include the name and email address in
863
   the log message. Since the ffmpeg-cvslog mailing list is publicly
864
   archived you should add some SPAM protection to the email address. Send an
865
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
866
   you applied the patch.
867
@item
868
   When applying patches that have been discussed (at length) on the mailing
869
   list, reference the thread in the log message.
870
@item
871
    Do NOT commit to code actively maintained by others without permission.
872
    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
873
    timeframe (12h for build failures and security fixes, 3 days small changes,
874
    1 week for big patches) then commit your patch if you think it is OK.
875
    Also note, the maintainer can simply ask for more time to review!
876
@item
877
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
878
    are sent there and reviewed by all the other developers. Bugs and possible
879
    improvements or general questions regarding commits are discussed there. We
880
    expect you to react if problems with your code are uncovered.
881
@item
882
    Update the documentation if you change behavior or add features. If you are
883
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
884
    maintainer(s) will review and commit your stuff.
885
@item
886
    Try to keep important discussions and requests (also) on the public
887
    developer mailing list, so that all developers can benefit from them.
888
@item
889
    Never write to unallocated memory, never write over the end of arrays,
890
    always check values read from some untrusted source before using them
891
    as array index or other risky things.
892
@item
893
    Remember to check if you need to bump versions for the specific libav
894
    parts (libavutil, libavcodec, libavformat) you are changing. You need
895
    to change the version integer and the version string.
896
    Incrementing the first component means no backward compatibility to
897
    previous versions (e.g. removal of a function from the public API).
898
    Incrementing the second component means backward compatible change
899
    (e.g. addition of a function to the public API).
900
    Incrementing the third component means a noteworthy binary compatible
901
    change (e.g. encoder bug fix that matters for the decoder).
902
@item
903
    If you add a new codec, remember to update the changelog, add it to
904
    the supported codecs table in the documentation and bump the second
905
    component of the @file{libavcodec} version number appropriately. If
906
    it has a fourcc, add it to @file{libavformat/riff.c}, even if it
907
    is only a decoder.
908
@item
909
    Compiler warnings indicate potential bugs or code with bad style. If a type of
910
    warning always points to correct and clean code, that warning should
911
    be disabled, not the code changed.
912
    Thus the remaining warnings can either be bugs or correct code.
913
    If it is a bug, the bug has to be fixed. If it is not, the code should
914
    be changed to not generate a warning unless that causes a slowdown
915
    or obfuscates the code.
916
@item
917
    If you add a new file, give it a proper license header. Do not copy and
918
    paste it from a random place, use an existing file as template.
919
@end enumerate
920

    
921
We think our rules are not too hard. If you have comments, contact us.
922

    
923
Note, these rules are mostly borrowed from the MPlayer project.
924

    
925
@section Submitting patches
926

    
927
First, (@pxref{Coding Rules}) above if you did not yet.
928

    
929
When you submit your patch, try to send a unified diff (diff '-up'
930
option). We cannot read other diffs :-)
931

    
932
Also please do not submit a patch which contains several unrelated changes.
933
Split it into separate, self-contained pieces. This does not mean splitting
934
file by file. Instead, make the patch as small as possible while still
935
keeping it as a logical unit that contains an individual change, even
936
if it spans multiple files. This makes reviewing your patches much easier
937
for us and greatly increases your chances of getting your patch applied.
938

    
939
Run the regression tests before submitting a patch so that you can
940
verify that there are no big problems.
941

    
942
Patches should be posted as base64 encoded attachments (or any other
943
encoding which ensures that the patch will not be trashed during
944
transmission) to the ffmpeg-devel mailing list, see
945
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
946

    
947
It also helps quite a bit if you tell us what the patch does (for example
948
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
949
and has no lrint()')
950

    
951
Also please if you send several patches, send each patch as a separate mail,
952
do not attach several unrelated patches to the same mail.
953

    
954
@section patch submission checklist
955

    
956
@enumerate
957
@item
958
    Do the regression tests pass with the patch applied?
959
@item
960
    Is the patch a unified diff?
961
@item
962
    Is the patch against latest FFmpeg SVN?
963
@item
964
    Are you subscribed to ffmpeg-dev?
965
    (the list is subscribers only due to spam)
966
@item
967
    Have you checked that the changes are minimal, so that the same cannot be
968
    achieved with a smaller patch and/or simpler final code?
969
@item
970
    If the change is to speed critical code, did you benchmark it?
971
@item
972
    If you did any benchmarks, did you provide them in the mail?
973
@item
974
    Have you checked that the patch does not introduce buffer overflows or
975
    other security issues?
976
@item
977
    If you add a new demuxer or decoder, have you checked that it does not
978
    crash with damaged input (see tools/trasher)?
979
@item
980
    Is the patch created from the root of the source tree, so it can be
981
    applied with @code{patch -p0}?
982
@item
983
    Does the patch not mix functional and cosmetic changes?
984
@item
985
    Did you add tabs or trailing whitespace to the code? Both are forbidden.
986
@item
987
    Is the patch attached to the email you send?
988
@item
989
    Is the mime type of the patch correct? It should be text/x-diff or
990
    text/x-patch or at least text/plain and not application/octet-stream.
991
@item
992
    If the patch fixes a bug, did you provide a verbose analysis of the bug?
993
@item
994
    If the patch fixes a bug, did you provide enough information, including
995
    a sample, so the bug can be reproduced and the fix can be verified?
996
    Note please do not attach samples >100k to mails but rather provide a
997
    URL, you can upload to ftp://upload.mplayerhq.hu
998
@item
999
    Did you provide a verbose summary about what the patch does change?
1000
@item
1001
    Did you provide a verbose explanation why it changes things like it does?
1002
@item
1003
    Did you provide a verbose summary of the user visible advantages and
1004
    disadvantages if the patch is applied?
1005
@item
1006
    Did you provide an example so we can verify the new feature added by the
1007
    patch easily?
1008
@item
1009
    If you added a new file, did you insert a license header? It should be
1010
    taken from FFmpeg, not randomly copied and pasted from somewhere else.
1011
@item
1012
    You should maintain alphabetical order in alphabetically ordered lists as
1013
    long as doing so does not break API/ABI compatibility.
1014
@item
1015
    Lines with similar content should be aligned vertically when doing so
1016
    improves readability.
1017
@item
1018
    Did you provide a suggestion for a clear commit log message?
1019
@item
1020
    Did you test your decoder or demuxer against damaged data? If no, see
1021
    tools/trasher and the noise bitstream filter. Your decoder or demuxer
1022
    should not crash or end in a (near) infinite loop when fed damaged data.
1023
@end enumerate
1024

    
1025
@section Patch review process
1026

    
1027
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1028
clear note that the patch is not for SVN.
1029
Reviews and comments will be posted as replies to the patch on the
1030
mailing list. The patch submitter then has to take care of every comment,
1031
that can be by resubmitting a changed patch or by discussion. Resubmitted
1032
patches will themselves be reviewed like any other patch. If at some point
1033
a patch passes review with no comments then it is approved, that can for
1034
simple and small patches happen immediately while large patches will generally
1035
have to be changed and reviewed many times before they are approved.
1036
After a patch is approved it will be committed to the repository.
1037

    
1038
We will review all submitted patches, but sometimes we are quite busy so
1039
especially for large patches this can take several weeks.
1040

    
1041
When resubmitting patches, please do not make any significant changes
1042
not related to the comments received during review. Such patches will
1043
be rejected. Instead, submit  significant changes or new features as
1044
separate patches.
1045

    
1046
@section Regression tests
1047

    
1048
Before submitting a patch (or committing to the repository), you should at least
1049
test that you did not break anything.
1050

    
1051
The regression tests build a synthetic video stream and a synthetic
1052
audio stream. These are then encoded and decoded with all codecs or
1053
formats. The CRC (or MD5) of each generated file is recorded in a
1054
result file. A 'diff' is launched to compare the reference results and
1055
the result file.
1056

    
1057
The regression tests then go on to test the FFserver code with a
1058
limited set of streams. It is important that this step runs correctly
1059
as well.
1060

    
1061
Run 'make test' to test all the codecs and formats.
1062

    
1063
Run 'make fulltest' to test all the codecs, formats and FFserver.
1064

    
1065
[Of course, some patches may change the results of the regression tests. In
1066
this case, the reference results of the regression tests shall be modified
1067
accordingly].
1068

    
1069
@bye