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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 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     @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,
479
you can build libavutil, libavcodec and libavformat as DLLs.
480

    
481
@end itemize
482

    
483
@subsection Microsoft Visual C++ compatibility
484

    
485
As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
486
want to use the libav* libraries in your own applications, you can still
487
compile those applications using MSVC++. But the libav* libraries you link
488
to @emph{must} be built with MinGW. However, you will not be able to debug
489
inside the libav* libraries, since MSVC++ does not recognize the debug
490
symbols generated by GCC.
491
We strongly recommend you to move over from MSVC++ to MinGW tools.
492

    
493
This description of how to use the FFmpeg libraries with MSVC++ is based on
494
Microsoft Visual C++ 2005 Express Edition. If you have a different version,
495
you might have to modify the procedures slightly.
496

    
497
@subsubsection Using static libraries
498

    
499
Assuming you have just built and installed FFmpeg in @file{/usr/local}.
500

    
501
@enumerate
502

    
503
@item Create a new console application ("File / New / Project") and then
504
select "Win32 Console Application". On the appropriate page of the
505
Application Wizard, uncheck the "Precompiled headers" option.
506

    
507
@item Write the source code for your application, or, for testing, just
508
copy the code from an existing sample application into the source file
509
that MSVC++ has already created for you. For example, you can copy
510
@file{output_example.c} from the FFmpeg distribution.
511

    
512
@item Open the "Project / Properties" dialog box. In the "Configuration"
513
combo box, select "All Configurations" so that the changes you make will
514
affect both debug and release builds. In the tree view on the left hand
515
side, select "C/C++ / General", then edit the "Additional Include
516
Directories" setting to contain the path where the FFmpeg includes were
517
installed (i.e. @file{c:\msys\1.0\local\include}).
518
Do not add MinGW's include directory here, or the include files will
519
conflict with MSVC's.
520

    
521
@item Still in the "Project / Properties" dialog box, select
522
"Linker / General" from the tree view and edit the
523
"Additional Library Directories" setting to contain the @file{lib}
524
directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
525
the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
526
and the directory where MinGW's GCC libs are installed
527
(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
528
"Linker / Input" from the tree view, and add the files @file{libavformat.a},
529
@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
530
@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
531
to the end of "Additional Dependencies".
532

    
533
@item Now, select "C/C++ / Code Generation" from the tree view. Select
534
"Debug" in the "Configuration" combo box. Make sure that "Runtime
535
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
536
the "Configuration" combo box and make sure that "Runtime Library" is
537
set to "Multi-threaded DLL".
538

    
539
@item Click "OK" to close the "Project / Properties" dialog box.
540

    
541
@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
542
Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
543
and install it in MSVC++'s include directory
544
(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
545

    
546
@item MSVC++ also does not understand the @code{inline} keyword used by
547
FFmpeg, so you must add this line before @code{#include}ing libav*:
548
@example
549
#define inline _inline
550
@end example
551

    
552
@item Build your application, everything should work.
553

    
554
@end enumerate
555

    
556
@subsubsection Using shared libraries
557

    
558
This is how to create DLL and LIB files that are compatible with MSVC++:
559

    
560
@enumerate
561

    
562
@item Add a call to @file{vcvars32.bat} (which sets up the environment
563
variables for the Visual C++ tools) as the first line of @file{msys.bat}.
564
The standard location for @file{vcvars32.bat} is
565
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
566
and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
567
If this corresponds to your setup, add the following line as the first line
568
of @file{msys.bat}:
569

    
570
@example
571
call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
572
@end example
573

    
574
Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
575
and run @file{c:\msys\1.0\msys.bat} from there.
576

    
577
@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
578
from @file{Microsoft (R) Library Manager}, this means your environment
579
variables are set up correctly, the @file{Microsoft (R) Library Manager}
580
is on the path and will be used by FFmpeg to create
581
MSVC++-compatible import libraries.
582

    
583
@item Build FFmpeg with
584

    
585
@example
586
./configure --enable-shared --enable-memalign-hack
587
make
588
make install
589
@end example
590

    
591
Your install path (@file{/usr/local/} by default) should now have the
592
necessary DLL and LIB files under the @file{bin} directory.
593

    
594
@end enumerate
595

    
596
To use those files with MSVC++, do the same as you would do with
597
the static libraries, as described above. But in Step 4,
598
you should only need to add the directory where the LIB files are installed
599
(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
600
installed in the @file{bin} directory. And instead of adding @file{libxx.a}
601
files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
602
@file{avutil.lib}. There should be no need for @file{libmingwex.a},
603
@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
604
statically linked into the DLLs. The @file{bin} directory contains a bunch
605
of DLL files, but the ones that are actually used to run your application
606
are the ones with a major version number in their filenames
607
(i.e. @file{avcodec-51.dll}).
608

    
609
@subsection Cross compilation for Windows with Linux
610

    
611
You must use the MinGW cross compilation tools available at
612
@url{http://www.mingw.org/}.
613

    
614
Then configure FFmpeg with the following options:
615
@example
616
./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
617
@end example
618
(you can change the cross-prefix according to the prefix chosen for the
619
MinGW tools).
620

    
621
Then you can easily test FFmpeg with Wine
622
(@url{http://www.winehq.com/}).
623

    
624
@subsection Compilation under Cygwin
625

    
626
The main issue with Cygwin is that newlib, its C library, does not
627
contain llrint().  However, it is possible to leverage the
628
implementation in MinGW.
629

    
630
Just install your Cygwin with all the "Base" packages, plus the
631
following "Devel" ones:
632
@example
633
binutils, gcc-core, make, subversion, mingw-runtime
634
@end example
635

    
636
Do not install binutils-20060709-1 (they are buggy on shared builds);
637
use binutils-20050610-1 instead.
638

    
639
Then create a small library that just contains llrint():
640

    
641
@example
642
ar x /usr/lib/mingw/libmingwex.a llrint.o
643
ar cq /usr/local/lib/libllrint.a llrint.o
644
@end example
645

    
646
Then run
647

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

    
652
to make a static build or
653

    
654
@example
655
./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
656
@end example
657

    
658
to build shared libraries.
659

    
660
If you want to build FFmpeg with additional libraries, download Cygwin
661
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
662
and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
663
(@url{http://cygwinports.dotsrc.org/}).
664

    
665
@subsection Crosscompilation for Windows under Cygwin
666

    
667
With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
668

    
669
Just install your Cygwin as explained before, plus these additional
670
"Devel" packages:
671
@example
672
gcc-mingw-core, mingw-runtime, mingw-zlib
673
@end example
674

    
675
and add some special flags to your configure invocation.
676

    
677
For a static build run
678
@example
679
./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
680
@end example
681

    
682
and for a build with shared libraries
683
@example
684
./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
685
@end example
686

    
687
@section BeOS
688

    
689
BeOS support is broken in mysterious ways.
690

    
691
@section OS/2
692

    
693
For information about compiling FFmpeg on OS/2 see
694
@url{http://www.edm2.com/index.php/FFmpeg}.
695

    
696
@chapter Developers Guide
697

    
698
@section API
699
@itemize @bullet
700
@item libavcodec is the library containing the codecs (both encoding and
701
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
702

    
703
@item libavformat is the library containing the file format handling (mux and
704
demux code for several formats). Look at @file{ffplay.c} to use it in a
705
player. See @file{output_example.c} to use it to generate audio or video
706
streams.
707

    
708
@end itemize
709

    
710
@section Integrating libavcodec or libavformat in your program
711

    
712
You can integrate all the source code of the libraries to link them
713
statically to avoid any version problem. All you need is to provide a
714
'config.mak' and a 'config.h' in the parent directory. See the defines
715
generated by ./configure to understand what is needed.
716

    
717
You can use libavcodec or libavformat in your commercial program, but
718
@emph{any patch you make must be published}. The best way to proceed is
719
to send your patches to the FFmpeg mailing list.
720

    
721
@node Coding Rules
722
@section Coding Rules
723

    
724
FFmpeg is programmed in the ISO C90 language with a few additional
725
features from ISO C99, namely:
726
@itemize @bullet
727
@item
728
the @samp{inline} keyword;
729
@item
730
@samp{//} comments;
731
@item
732
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
733
@item
734
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
735
@end itemize
736

    
737
These features are supported by all compilers we care about, so we will not
738
accept patches to remove their use unless they absolutely do not impair
739
clarity and performance.
740

    
741
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
742
compiles with several other compilers, such as the Compaq ccc compiler
743
or Sun Studio 9, and we would like to keep it that way unless it would
744
be exceedingly involved. To ensure compatibility, please do not use any
745
additional C99 features or GCC extensions. Especially watch out for:
746
@itemize @bullet
747
@item
748
mixing statements and declarations;
749
@item
750
@samp{long long} (use @samp{int64_t} instead);
751
@item
752
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
753
@item
754
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
755
@end itemize
756

    
757
Indent size is 4.
758
The presentation is the one specified by 'indent -i4 -kr -nut'.
759
The TAB character is forbidden outside of Makefiles as is any
760
form of trailing whitespace. Commits containing either will be
761
rejected by the Subversion repository.
762

    
763
The main priority in FFmpeg is simplicity and small code size in order to
764
minimize the bug count.
765

    
766
Comments: Use the JavaDoc/Doxygen
767
format (see examples below) so that code documentation
768
can be generated automatically. All nontrivial functions should have a comment
769
above them explaining what the function does, even if it is just one sentence.
770
All structures and their member variables should be documented, too.
771
@example
772
/**
773
 * @@file mpeg.c
774
 * MPEG codec.
775
 * @@author ...
776
 */
777

    
778
/**
779
 * Summary sentence.
780
 * more text ...
781
 * ...
782
 */
783
typedef struct Foobar@{
784
    int var1; /**< var1 description */
785
    int var2; ///< var2 description
786
    /** var3 description */
787
    int var3;
788
@} Foobar;
789

    
790
/**
791
 * Summary sentence.
792
 * more text ...
793
 * ...
794
 * @@param my_parameter description of my_parameter
795
 * @@return return value description
796
 */
797
int myfunc(int my_parameter)
798
...
799
@end example
800

    
801
fprintf and printf are forbidden in libavformat and libavcodec,
802
please use av_log() instead.
803

    
804
Casts should be used only when necessary. Unneeded parentheses
805
should also be avoided if they don't make the code easier to understand.
806

    
807
@section Development Policy
808

    
809
@enumerate
810
@item
811
   Contributions should be licensed under the LGPL 2.1, including an
812
   "or any later version" clause, or the MIT license.  GPL 2 including
813
   an "or any later version" clause is also acceptable, but LGPL is
814
   preferred.
815
@item
816
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
817
   enabled code which breaks compilation or compiles but does not work or
818
   breaks the regression tests)
819
   You can commit unfinished stuff (for testing etc), but it must be disabled
820
   (#ifdef etc) by default so it does not interfere with other developers'
821
   work.
822
@item
823
   You do not have to over-test things. If it works for you, and you think it
824
   should work for others, then commit. If your code has problems
825
   (portability, triggers compiler bugs, unusual environment etc) they will be
826
   reported and eventually fixed.
827
@item
828
   Do not commit unrelated changes together, split them into self-contained
829
   pieces. Also do not forget that if part B depends on part A, but A does not
830
   depend on B, then A can and should be committed first and separate from B.
831
   Keeping changes well split into self-contained parts makes reviewing and
832
   understanding them on the commit log mailing list easier. This also helps
833
   in case of debugging later on.
834
   Also if you have doubts about splitting or not splitting, do not hesitate to
835
   ask/discuss it on the developer mailing list.
836
@item
837
   Do not change behavior of the program (renaming options etc) without
838
   first discussing it on the ffmpeg-devel mailing list. Do not remove
839
   functionality from the code. Just improve!
840

    
841
   Note: Redundant code can be removed.
842
@item
843
   Do not commit changes to the build system (Makefiles, configure script)
844
   which change behavior, defaults etc, without asking first. The same
845
   applies to compiler warning fixes, trivial looking fixes and to code
846
   maintained by other developers. We usually have a reason for doing things
847
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
848
   list, and if the code maintainers say OK, you may commit. This does not
849
   apply to files you wrote and/or maintain.
850
@item
851
   We refuse source indentation and other cosmetic changes if they are mixed
852
   with functional changes, such commits will be rejected and removed. Every
853
   developer has his own indentation style, you should not change it. Of course
854
   if you (re)write something, you can use your own style, even though we would
855
   prefer if the indentation throughout FFmpeg was consistent (Many projects
856
   force a given indentation style - we do not.). If you really need to make
857
   indentation changes (try to avoid this), separate them strictly from real
858
   changes.
859

    
860
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
861
   then either do NOT change the indentation of the inner part within (do not
862
   move it to the right)! or do so in a separate commit
863
@item
864
   Always fill out the commit log message. Describe in a few lines what you
865
   changed and why. You can refer to mailing list postings if you fix a
866
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
867
@item
868
   If you apply a patch by someone else, include the name and email address in
869
   the log message. Since the ffmpeg-cvslog mailing list is publicly
870
   archived you should add some SPAM protection to the email address. Send an
871
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
872
   you applied the patch.
873
@item
874
   When applying patches that have been discussed (at length) on the mailing
875
   list, reference the thread in the log message.
876
@item
877
    Do NOT commit to code actively maintained by others without permission.
878
    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
879
    timeframe (12h for build failures and security fixes, 3 days small changes,
880
    1 week for big patches) then commit your patch if you think it is OK.
881
    Also note, the maintainer can simply ask for more time to review!
882
@item
883
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
884
    are sent there and reviewed by all the other developers. Bugs and possible
885
    improvements or general questions regarding commits are discussed there. We
886
    expect you to react if problems with your code are uncovered.
887
@item
888
    Update the documentation if you change behavior or add features. If you are
889
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
890
    maintainer(s) will review and commit your stuff.
891
@item
892
    Try to keep important discussions and requests (also) on the public
893
    developer mailing list, so that all developers can benefit from them.
894
@item
895
    Never write to unallocated memory, never write over the end of arrays,
896
    always check values read from some untrusted source before using them
897
    as array index or other risky things.
898
@item
899
    Remember to check if you need to bump versions for the specific libav
900
    parts (libavutil, libavcodec, libavformat) you are changing. You need
901
    to change the version integer and the version string.
902
    Incrementing the first component means no backward compatibility to
903
    previous versions (e.g. removal of a function from the public API).
904
    Incrementing the second component means backward compatible change
905
    (e.g. addition of a function to the public API).
906
    Incrementing the third component means a noteworthy binary compatible
907
    change (e.g. encoder bug fix that matters for the 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 New codecs or formats checklist
955

    
956
@enumerate
957
@item
958
    Did you use av_cold for codec initialization and close functions?
959
@item
960
    Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
961
    AVInputFormat/AVOutputFormat struct?
962
@item
963
    Did you bump the minor version number in @file{avcodec.h} or
964
    @file{avformat.h}?
965
@item
966
    Did you register it in @file{allcodecs.c} or @file{allformats.c}?
967
@item
968
    Did you add the CodecID to @file{avcodec.h}?
969
@item
970
    If it has a fourcc, did you add it to @file{libavformat/riff.c},
971
    even if it is only a decoder?
972
@item
973
    Did you add a rule to compile the appropriate files in the Makefile?
974
    Remember to do this even if you're just adding a format to a file that is
975
    already being compiled by some other rule, like a raw demuxer.
976
@item
977
    Did you add an entry to the table of supported formats or codecs in the
978
    documentation?
979
@item
980
    Did you add an entry in the Changelog?
981
@item
982
    If it depends on a parser or a library, did you add that dependency in
983
    configure?
984
@item
985
    Did you "svn add" the appropriate files before commiting?
986
@end enumerate
987

    
988
@section patch submission checklist
989

    
990
@enumerate
991
@item
992
    Do the regression tests pass with the patch applied?
993
@item
994
    Is the patch a unified diff?
995
@item
996
    Is the patch against latest FFmpeg SVN?
997
@item
998
    Are you subscribed to ffmpeg-dev?
999
    (the list is subscribers only due to spam)
1000
@item
1001
    Have you checked that the changes are minimal, so that the same cannot be
1002
    achieved with a smaller patch and/or simpler final code?
1003
@item
1004
    If the change is to speed critical code, did you benchmark it?
1005
@item
1006
    If you did any benchmarks, did you provide them in the mail?
1007
@item
1008
    Have you checked that the patch does not introduce buffer overflows or
1009
    other security issues?
1010
@item
1011
    If you add a new demuxer or decoder, have you checked that it does not
1012
    crash with damaged input (see tools/trasher)?
1013
@item
1014
    Is the patch created from the root of the source tree, so it can be
1015
    applied with @code{patch -p0}?
1016
@item
1017
    Does the patch not mix functional and cosmetic changes?
1018
@item
1019
    Did you add tabs or trailing whitespace to the code? Both are forbidden.
1020
@item
1021
    Is the patch attached to the email you send?
1022
@item
1023
    Is the mime type of the patch correct? It should be text/x-diff or
1024
    text/x-patch or at least text/plain and not application/octet-stream.
1025
@item
1026
    If the patch fixes a bug, did you provide a verbose analysis of the bug?
1027
@item
1028
    If the patch fixes a bug, did you provide enough information, including
1029
    a sample, so the bug can be reproduced and the fix can be verified?
1030
    Note please do not attach samples >100k to mails but rather provide a
1031
    URL, you can upload to ftp://upload.mplayerhq.hu
1032
@item
1033
    Did you provide a verbose summary about what the patch does change?
1034
@item
1035
    Did you provide a verbose explanation why it changes things like it does?
1036
@item
1037
    Did you provide a verbose summary of the user visible advantages and
1038
    disadvantages if the patch is applied?
1039
@item
1040
    Did you provide an example so we can verify the new feature added by the
1041
    patch easily?
1042
@item
1043
    If you added a new file, did you insert a license header? It should be
1044
    taken from FFmpeg, not randomly copied and pasted from somewhere else.
1045
@item
1046
    You should maintain alphabetical order in alphabetically ordered lists as
1047
    long as doing so does not break API/ABI compatibility.
1048
@item
1049
    Lines with similar content should be aligned vertically when doing so
1050
    improves readability.
1051
@item
1052
    Did you provide a suggestion for a clear commit log message?
1053
@item
1054
    Did you test your decoder or demuxer against damaged data? If no, see
1055
    tools/trasher and the noise bitstream filter. Your decoder or demuxer
1056
    should not crash or end in a (near) infinite loop when fed damaged data.
1057
@end enumerate
1058

    
1059
@section Patch review process
1060

    
1061
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1062
clear note that the patch is not for SVN.
1063
Reviews and comments will be posted as replies to the patch on the
1064
mailing list. The patch submitter then has to take care of every comment,
1065
that can be by resubmitting a changed patch or by discussion. Resubmitted
1066
patches will themselves be reviewed like any other patch. If at some point
1067
a patch passes review with no comments then it is approved, that can for
1068
simple and small patches happen immediately while large patches will generally
1069
have to be changed and reviewed many times before they are approved.
1070
After a patch is approved it will be committed to the repository.
1071

    
1072
We will review all submitted patches, but sometimes we are quite busy so
1073
especially for large patches this can take several weeks.
1074

    
1075
When resubmitting patches, please do not make any significant changes
1076
not related to the comments received during review. Such patches will
1077
be rejected. Instead, submit  significant changes or new features as
1078
separate patches.
1079

    
1080
@section Regression tests
1081

    
1082
Before submitting a patch (or committing to the repository), you should at least
1083
test that you did not break anything.
1084

    
1085
The regression tests build a synthetic video stream and a synthetic
1086
audio stream. These are then encoded and decoded with all codecs or
1087
formats. The CRC (or MD5) of each generated file is recorded in a
1088
result file. A 'diff' is launched to compare the reference results and
1089
the result file.
1090

    
1091
The regression tests then go on to test the FFserver code with a
1092
limited set of streams. It is important that this step runs correctly
1093
as well.
1094

    
1095
Run 'make test' to test all the codecs and formats.
1096

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

    
1099
[Of course, some patches may change the results of the regression tests. In
1100
this case, the reference results of the regression tests shall be modified
1101
accordingly].
1102

    
1103
@bye