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\input texinfo @c -*- texinfo -*-
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@settitle General Documentation
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@titlepage
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@sp 7
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@center @titlefont{General Documentation}
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@sp 3
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@end titlepage
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@chapter external libraries
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FFmpeg can be hooked up with a number of external libraries to add support
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for more formats. None of them are used by default, their use has to be
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explicitly requested by passing the appropriate flags to @file{./configure}.
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@section AMR
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AMR comes in two different flavors, wideband and narrowband. FFmpeg can make
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use of the AMR wideband (floating-point mode) and the AMR narrowband
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(floating-point mode) reference decoders and encoders.
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Go to @url{http://www.penguin.cz/~utx/amr} and follow the instructions for
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installing the libraries. Then pass @code{--enable-libamr-nb} and/or
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@code{--enable-libamr-wb} to configure to enable the libraries.
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Note that libamr is copyrighted without any sort of license grant. This means
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that you can use it if you legally obtained it but you are not allowed to
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redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
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you create are non-free and unredistributable!}
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@chapter Supported File Formats and Codecs
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You can use the @code{-formats} option to have an exhaustive list.
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@section File Formats
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FFmpeg supports the following file formats through the @code{libavformat}
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library:
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@multitable @columnfractions .4 .1 .1 .4
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@item Name @tab Encoding @tab Decoding @tab Comments
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@item 4xm                       @tab   @tab X
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    @tab 4X Technologies format, used in some games.
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@item ADTS AAC audio            @tab X @tab X
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@item American Laser Games MM   @tab   @tab X
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    @tab Multimedia format used in games like Mad Dog McCree.
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@item ASF                       @tab X @tab X
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@item AVI                       @tab X @tab X
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@item AVM2 (Flash 9)            @tab X @tab X
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    @tab Only embedded audio is decoded.
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@item AVS                       @tab   @tab X
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    @tab Multimedia format used by the Creature Shock game.
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@item Bethsoft VID              @tab   @tab X
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    @tab Used in some games from Bethesda Softworks.
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@item BFI                       @tab   @tab X
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    @tab Brute Force & Ignorance, used in Flash Traffic: City of Angels.
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@item C93                       @tab   @tab X
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    @tab Used in the game Cyberia from Interplay.
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@item CIN                       @tab   @tab X
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    @tab Multimedia format used by Delphine Software games.
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@item Creative VOC              @tab X @tab X
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    @tab Created for the Sound Blaster Pro.
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@item CRYO APC                  @tab   @tab X
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    @tab Audio format used in some games by CRYO Interactive Entertainment.
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@item DV                        @tab X @tab X
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@item DXA                       @tab   @tab X
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    @tab This format is used in the non-Windows version of the Feeble Files
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         game and different game cutscenes repacked for use with ScummVM.
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@item Electronic Arts Multimedia  @tab    @tab X
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    @tab Used in various EA games; files have extensions like WVE and UV2.
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@item FLIC                      @tab   @tab X
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    @tab .fli/.flc files
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@item FLV                       @tab X @tab X
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    @tab Macromedia Flash video files
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@item GXF                       @tab X @tab X
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    @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley
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         playout servers.
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@item id Cinematic              @tab   @tab X
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    @tab Used in Quake II.
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@item id RoQ                    @tab X @tab X
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    @tab Used in Quake III, Jedi Knight 2, other computer games.
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@item IFF                       @tab   @tab X
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    @tab Interchange File Format
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@item Interplay MVE             @tab   @tab X
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    @tab Format used in various Interplay computer games.
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@item LMLM4                     @tab   @tab X
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    @tab Used by Linux Media Labs MPEG-4 PCI boards
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@item Matroska                  @tab X @tab X
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@item MAXIS EA XA               @tab   @tab X
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    @tab Used in Sim City 3000; file extension .xa.
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@item Monkey's Audio            @tab   @tab X
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@item Motion Pixels MVI         @tab   @tab X
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@item MOV/QuickTime             @tab X @tab X
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@item MPEG audio                @tab X @tab X
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@item MPEG-1 systems            @tab X @tab X
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    @tab muxed audio and video
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@item MPEG-2 PS                 @tab X @tab X
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    @tab also known as @code{VOB} file
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@item MPEG-2 TS                 @tab   @tab X
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    @tab also known as DVB Transport Stream
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@item MPEG-4                    @tab X @tab X
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    @tab MPEG-4 is a variant of QuickTime.
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@item MSN TCP webcam            @tab   @tab X
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    @tab Used by MSN Messenger webcam streams.
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@item MXF                       @tab X @tab X
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    @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
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@item Nullsoft Video            @tab   @tab X
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@item NUT                       @tab X @tab X
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    @tab NUT Open Container Format
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@item OMA                       @tab   @tab X
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    @tab Audio format used in Sony Sonic Stage and Sony Vegas.
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@item PlayStation STR           @tab   @tab X
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@item PVA                       @tab   @tab X
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    @tab Used by TechnoTrend DVB PCI boards.
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@item raw AC-3                  @tab X @tab X
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@item raw CRI ADX audio         @tab X @tab X
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@item raw MJPEG                 @tab X @tab X
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@item raw MPEG video            @tab X @tab X
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@item raw MPEG-4 video          @tab X @tab X
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@item raw PCM 8/16/32 bits, 32/64-bit floating point, mu-law/A-law @tab X  @tab  X
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@item raw Shorten audio         @tab    @tab  X
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@item RealMedia                 @tab X @tab X
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@item RL2                       @tab   @tab X
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    @tab Audio and video format used in some games by Entertainment Software Partners.
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@item Sega FILM/CPK             @tab   @tab X
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    @tab Used in many Sega Saturn console games.
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@item SEQ                       @tab   @tab X
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    @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
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@item Sierra Online             @tab   @tab X
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    @tab .sol files used in Sierra Online games.
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@item Sierra VMD                @tab   @tab X
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    @tab Used in Sierra CD-ROM games.
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@item SIFF                      @tab   @tab X
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    @tab Audio and video format used in some games by Beam Software.
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@item Smacker                   @tab   @tab X
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    @tab Multimedia format used by many games.
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@item SUN AU format             @tab X @tab X
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@item THP                       @tab   @tab X
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    @tab Used on the Nintendo GameCube.
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@item WAV                       @tab X @tab X
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@item WC3 Movie                 @tab   @tab X
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    @tab Multimedia format used in Origin's Wing Commander III computer game.
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@item Westwood Studios VQA/AUD  @tab   @tab X
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    @tab Multimedia formats used in Westwood Studios games.
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@end multitable
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@code{X} means that encoding (resp. decoding) is supported.
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@section Image Formats
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FFmpeg can read and write images for each frame of a video sequence. The
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following image formats are supported:
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@multitable @columnfractions .4 .1 .1 .4
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@item Name @tab Encoding @tab Decoding @tab Comments
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@item .Y.U.V       @tab X @tab X @tab one raw file per component
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@item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
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@item JPEG         @tab X @tab X @tab Progressive JPEG is not supported.
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@item 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 Name @tab Encoding @tab Decoding @tab Comments
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@item 4X Video               @tab     @tab  X
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    @tab Used in certain computer games.
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@item American Laser Games Video  @tab    @tab X
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    @tab Used in games like Mad Dog McCree.
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@item AMV                    @tab     @tab  X
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    @tab Used in Chinese MP3 players.
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@item Apple Animation        @tab  X  @tab  X
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    @tab fourcc: 'rle '
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@item Apple Graphics         @tab     @tab  X
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    @tab fourcc: 'smc '
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@item Apple MJPEG-B          @tab     @tab  X
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@item Apple QuickDraw        @tab     @tab  X
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    @tab fourcc: qdrw
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@item Apple Video            @tab     @tab  X
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    @tab fourcc: rpza
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@item Asus v1                @tab  X  @tab  X
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    @tab fourcc: ASV1
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@item Asus v2                @tab  X  @tab  X
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    @tab fourcc: ASV2
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@item ATI VCR1               @tab     @tab  X
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    @tab fourcc: VCR1
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@item ATI VCR2               @tab     @tab  X
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    @tab fourcc: VCR2
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@item Autodesk RLE           @tab     @tab  X
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    @tab fourcc: AASC
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@item AVID DNxHD             @tab   X @tab  X
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    @tab aka SMPTE VC3
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@item AVS video              @tab     @tab  X
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    @tab Video encoding used by the Creature Shock game.
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@item Bethsoft VID           @tab     @tab  X
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    @tab Used in some games from Bethesda Softworks.
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@item C93 video              @tab     @tab  X
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    @tab Codec used in Cyberia game.
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@item CamStudio              @tab     @tab  X
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    @tab fourcc: CSCD
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@item Cin video              @tab     @tab  X
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    @tab Codec used in Delphine Software games.
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@item Cinepak                @tab     @tab  X
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@item Cirrus Logic AccuPak   @tab     @tab  X
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    @tab fourcc: CLJR
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@item Creative YUV           @tab     @tab  X
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    @tab fourcc: CYUV
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@item Dirac                  @tab  X  @tab  X
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    @tab Supported through the external libdirac/libschroedinger libraries.
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@item Duck TrueMotion v1     @tab     @tab  X
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    @tab fourcc: DUCK
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@item Duck TrueMotion v2     @tab     @tab  X
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    @tab fourcc: TM20
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@item DV                     @tab  X  @tab  X
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@item DXA Video              @tab     @tab  X
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    @tab Codec originally used in Feeble Files game.
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@item Electronic Arts CMV    @tab     @tab  X
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    @tab Used in NHL 95 game.
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@item Electronic Arts TGV    @tab     @tab  X
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@item FFmpeg Video 1         @tab  X  @tab  X
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    @tab experimental lossless codec (fourcc: FFV1)
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@item Flash Screen Video     @tab  X  @tab  X
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    @tab fourcc: FSV1
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@item FLIC video             @tab     @tab  X
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@item FLV                    @tab  X  @tab  X
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    @tab Sorenson H.263 used in Flash
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@item Fraps FPS1             @tab     @tab  X
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@item H.261                  @tab  X  @tab  X
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@item H.263(+)               @tab  X  @tab  X
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    @tab also known as RealVideo 1.0
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@item H.264                  @tab     @tab  X
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@item HuffYUV                @tab  X  @tab  X
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@item IBM Ultimotion         @tab     @tab  X
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    @tab fourcc: ULTI
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@item id Cinematic video     @tab     @tab  X
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    @tab Used in Quake II.
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@item id RoQ                 @tab  X  @tab  X
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    @tab Used in Quake III, Jedi Knight 2, other computer games.
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@item Intel Indeo 3          @tab     @tab  X
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@item Interplay Video        @tab     @tab  X
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    @tab Used in Interplay .MVE files.
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@item JPEG-LS                @tab  X  @tab  X
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    @tab fourcc: MJLS, lossless and near-lossless is supported.
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@item KMVC                   @tab     @tab  X
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    @tab Codec used in Worms games.
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@item LOCO                   @tab     @tab  X
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@item lossless MJPEG         @tab  X  @tab  X
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@item Microsoft RLE          @tab     @tab  X
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@item Microsoft Video-1      @tab     @tab  X
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@item Mimic                  @tab     @tab  X
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    @tab Used in MSN Messenger Webcam streams.
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@item Miro VideoXL           @tab     @tab  X
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    @tab fourcc: VIXL
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@item MJPEG                  @tab  X  @tab  X
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@item Motion Pixels Video    @tab     @tab  X
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@item MPEG-1                 @tab  X  @tab  X
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@item MPEG-2                 @tab  X  @tab  X
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@item MPEG-4                 @tab  X  @tab  X
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@item MSMPEG4 V1             @tab  X  @tab  X
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@item MSMPEG4 V2             @tab  X  @tab  X
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@item MSMPEG4 V3             @tab  X  @tab  X
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@item MSZH                   @tab     @tab  X
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    @tab Part of LCL
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@item On2 VP3                @tab     @tab  X
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    @tab still experimental
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@item On2 VP5                @tab     @tab  X
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    @tab fourcc: VP50
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@item On2 VP6                @tab     @tab  X
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    @tab fourcc: VP60,VP61,VP62
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@item planar RGB             @tab     @tab  X
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    @tab fourcc: 8BPS
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@item QPEG                   @tab     @tab  X
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    @tab fourccs: QPEG, Q1.0, Q1.1
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@item RealVideo 1.0          @tab  X  @tab  X
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@item RealVideo 2.0          @tab  X  @tab  X
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@item Renderware TXD         @tab     @tab  X
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    @tab Texture dictionaries used by the Renderware Engine.
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@item RTjpeg                 @tab     @tab  X
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    @tab Video encoding used in NuppelVideo files.
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@item Smacker video          @tab     @tab  X
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    @tab Video encoding used in Smacker.
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@item Snow                   @tab  X  @tab  X
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    @tab experimental wavelet codec (fourcc: SNOW)
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@item Sony PlayStation MDEC  @tab     @tab  X
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@item Sorenson Video 1       @tab  X  @tab  X
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    @tab fourcc: SVQ1
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@item Sorenson Video 3       @tab     @tab  X
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    @tab fourcc: SVQ3
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@item Sunplus MJPEG          @tab     @tab  X
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    @tab fourcc: SP5X
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@item TechSmith Camtasia     @tab     @tab  X
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    @tab fourcc: TSCC
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@item Theora                 @tab  X  @tab  X
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    @tab still experimental
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@item THP                    @tab     @tab  X
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    @tab Used on the Nintendo GameCube.
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@item Tiertex Seq video      @tab     @tab  X
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    @tab Codec used in DOS CD-ROM FlashBack game.
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@item VC-1                   @tab     @tab  X
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@item VMD Video              @tab     @tab  X
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    @tab Used in Sierra VMD files.
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@item VMware Video           @tab     @tab  X
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    @tab Codec used in videos captured by VMware.
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@item Westwood VQA           @tab     @tab  X
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@item Winnov WNV1            @tab     @tab  X
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@item WMV7                   @tab  X  @tab  X
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@item WMV8                   @tab  X  @tab  X
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@item WMV9                   @tab     @tab  X
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    @tab not completely working
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@item Xan/WC3                @tab     @tab  X
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    @tab Used in Wing Commander III .MVE files.
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@item ZLIB                   @tab  X  @tab  X
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    @tab part of LCL, encoder experimental
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@item ZMBV                   @tab   X @tab  X
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    @tab Encoder works only in PAL8.
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@end multitable
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@code{X} means that encoding (resp. decoding) is supported.
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@section Audio Codecs
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@multitable @columnfractions .4 .1 .1 .1 .7
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@item Name @tab Encoding @tab Decoding @tab Comments
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@item 4X IMA ADPCM           @tab     @tab  X
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@item 8SVX audio             @tab     @tab  X
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@item AAC                    @tab  X  @tab  X
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    @tab Encoding is supported through the external library libfaac.
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@item AC-3                   @tab IX  @tab IX
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@item AMR-NB                 @tab  X  @tab  X
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    @tab Supported through an external library.
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@item AMR-WB                 @tab  X  @tab  X
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    @tab Supported through an external library.
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@item AMV IMA ADPCM          @tab     @tab  X
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    @tab Used in AMV files
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@item Apple lossless audio   @tab  X  @tab  X
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    @tab QuickTime fourcc 'alac'
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@item Apple MACE 3           @tab     @tab  X
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@item Apple MACE 6           @tab     @tab  X
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@item ATRAC 3                @tab     @tab  X
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@item CD-ROM XA ADPCM        @tab     @tab  X
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@item Cin audio              @tab     @tab  X
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    @tab Codec used in Delphine Software International games.
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@item Creative ADPCM         @tab     @tab  X
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    @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
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@item CRI ADX ADPCM          @tab  X  @tab  X
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    @tab Used in Sega Dreamcast games.
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@item DSP Group TrueSpeech   @tab     @tab  X
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@item DTS Coherent Audio     @tab     @tab  X
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@item Duck DK3 IMA ADPCM     @tab     @tab  X
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    @tab Used in some Sega Saturn console games.
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@item Duck DK4 IMA ADPCM     @tab     @tab  X
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    @tab Used in some Sega Saturn console games.
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@item DV audio               @tab     @tab  X
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@item Electronic Arts ADPCM  @tab     @tab  X
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    @tab Used in various EA titles.
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@item Enhanced AC-3          @tab     @tab  X
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@item FLAC lossless audio    @tab IX  @tab  X
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@item G.726  ADPCM           @tab  X  @tab  X
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@item 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  X  @tab  X
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@item Qdesign QDM2           @tab     @tab  X
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    @tab There are still some distortions.
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@item QT IMA ADPCM           @tab  X  @tab  X
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@item RA144                  @tab     @tab  X
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    @tab Real 14400 bit/s codec
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@item RA288                  @tab     @tab  X
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    @tab Real 28800 bit/s codec
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@item RADnet                 @tab IX  @tab IX
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    @tab Real low bitrate AC-3 codec
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@item Real COOK              @tab     @tab  X
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    @tab All versions except 5.1 are supported.
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@item Shorten                @tab     @tab  X
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@item Sierra Online DPCM     @tab     @tab  X
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    @tab Used in Sierra Online game audio files.
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@item Smacker audio          @tab     @tab  X
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@item SMJPEG IMA ADPCM       @tab     @tab  X
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    @tab Used in certain Loki game ports.
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@item Sonic                  @tab  X  @tab  X
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    @tab experimental codec
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@item Sonic lossless         @tab  X  @tab  X
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    @tab experimental codec
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@item 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://ffmpeg.arrozcru.org/}.
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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 latest versions of MSYS and MinGW from @url{http://www.mingw.org/}.
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You can find detailed installation
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instructions in the download section and the FAQ.
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FFmpeg does not build out-of-the-box with the packages the automated MinGW
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installer provides. It also requires coreutils to be installed and many other
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packages updated to the latest version. The minimum version for some packages
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are listed below:
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@itemize
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@item bash 3.1
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@item msys-make 3.81-2 (note: not mingw32-make)
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@item w32api 3.12
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@item mingw-runtime 3.15
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@end itemize
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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 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}.
483
Edit the @file{bin/sdl-config} script so that it points to the correct prefix
484
where SDL was installed. Verify that @file{sdl-config} can be launched from
485
the MSYS command line.
486

    
487
@item By using @code{./configure --enable-shared} when configuring FFmpeg,
488
you can build libavutil, libavcodec and libavformat as DLLs.
489

    
490
@end itemize
491

    
492
@subsection Microsoft Visual C++ compatibility
493

    
494
As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
495
want to use the libav* libraries in your own applications, you can still
496
compile those applications using MSVC++. But the libav* libraries you link
497
to @emph{must} be built with MinGW. However, you will not be able to debug
498
inside the libav* libraries, since MSVC++ does not recognize the debug
499
symbols generated by GCC.
500
We strongly recommend you to move over from MSVC++ to MinGW tools.
501

    
502
This description of how to use the FFmpeg libraries with MSVC++ is based on
503
Microsoft Visual C++ 2005 Express Edition. If you have a different version,
504
you might have to modify the procedures slightly.
505

    
506
@subsubsection Using static libraries
507

    
508
Assuming you have just built and installed FFmpeg in @file{/usr/local}.
509

    
510
@enumerate
511

    
512
@item Create a new console application ("File / New / Project") and then
513
select "Win32 Console Application". On the appropriate page of the
514
Application Wizard, uncheck the "Precompiled headers" option.
515

    
516
@item Write the source code for your application, or, for testing, just
517
copy the code from an existing sample application into the source file
518
that MSVC++ has already created for you. For example, you can copy
519
@file{output_example.c} from the FFmpeg distribution.
520

    
521
@item Open the "Project / Properties" dialog box. In the "Configuration"
522
combo box, select "All Configurations" so that the changes you make will
523
affect both debug and release builds. In the tree view on the left hand
524
side, select "C/C++ / General", then edit the "Additional Include
525
Directories" setting to contain the path where the FFmpeg includes were
526
installed (i.e. @file{c:\msys\1.0\local\include}).
527
Do not add MinGW's include directory here, or the include files will
528
conflict with MSVC's.
529

    
530
@item Still in the "Project / Properties" dialog box, select
531
"Linker / General" from the tree view and edit the
532
"Additional Library Directories" setting to contain the @file{lib}
533
directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
534
the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
535
and the directory where MinGW's GCC libs are installed
536
(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
537
"Linker / Input" from the tree view, and add the files @file{libavformat.a},
538
@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
539
@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
540
to the end of "Additional Dependencies".
541

    
542
@item Now, select "C/C++ / Code Generation" from the tree view. Select
543
"Debug" in the "Configuration" combo box. Make sure that "Runtime
544
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
545
the "Configuration" combo box and make sure that "Runtime Library" is
546
set to "Multi-threaded DLL".
547

    
548
@item Click "OK" to close the "Project / Properties" dialog box.
549

    
550
@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
551
Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
552
and install it in MSVC++'s include directory
553
(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
554

    
555
@item MSVC++ also does not understand the @code{inline} keyword used by
556
FFmpeg, so you must add this line before @code{#include}ing libav*:
557
@example
558
#define inline _inline
559
@end example
560

    
561
@item Build your application, everything should work.
562

    
563
@end enumerate
564

    
565
@subsubsection Using shared libraries
566

    
567
This is how to create DLL and LIB files that are compatible with MSVC++:
568

    
569
@enumerate
570

    
571
@item Add a call to @file{vcvars32.bat} (which sets up the environment
572
variables for the Visual C++ tools) as the first line of @file{msys.bat}.
573
The standard location for @file{vcvars32.bat} is
574
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
575
and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
576
If this corresponds to your setup, add the following line as the first line
577
of @file{msys.bat}:
578

    
579
@example
580
call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
581
@end example
582

    
583
Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
584
and run @file{c:\msys\1.0\msys.bat} from there.
585

    
586
@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
587
from @file{Microsoft (R) Library Manager}, this means your environment
588
variables are set up correctly, the @file{Microsoft (R) Library Manager}
589
is on the path and will be used by FFmpeg to create
590
MSVC++-compatible import libraries.
591

    
592
@item Build FFmpeg with
593

    
594
@example
595
./configure --enable-shared --enable-memalign-hack
596
make
597
make install
598
@end example
599

    
600
Your install path (@file{/usr/local/} by default) should now have the
601
necessary DLL and LIB files under the @file{bin} directory.
602

    
603
@end enumerate
604

    
605
To use those files with MSVC++, do the same as you would do with
606
the static libraries, as described above. But in Step 4,
607
you should only need to add the directory where the LIB files are installed
608
(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
609
installed in the @file{bin} directory. And instead of adding @file{libxx.a}
610
files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
611
@file{avutil.lib}. There should be no need for @file{libmingwex.a},
612
@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
613
statically linked into the DLLs. The @file{bin} directory contains a bunch
614
of DLL files, but the ones that are actually used to run your application
615
are the ones with a major version number in their filenames
616
(i.e. @file{avcodec-51.dll}).
617

    
618
@subsection Cross compilation for Windows with Linux
619

    
620
You must use the MinGW cross compilation tools available at
621
@url{http://www.mingw.org/}.
622

    
623
Then configure FFmpeg with the following options:
624
@example
625
./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
626
@end example
627
(you can change the cross-prefix according to the prefix chosen for the
628
MinGW tools).
629

    
630
Then you can easily test FFmpeg with Wine
631
(@url{http://www.winehq.com/}).
632

    
633
@subsection Compilation under Cygwin
634

    
635
The main issue with Cygwin is that newlib, its C library, does not
636
contain llrint().  However, it is possible to leverage the
637
implementation in MinGW.
638

    
639
Just install your Cygwin with all the "Base" packages, plus the
640
following "Devel" ones:
641
@example
642
binutils, gcc-core, make, subversion, mingw-runtime
643
@end example
644

    
645
Do not install binutils-20060709-1 (they are buggy on shared builds);
646
use binutils-20050610-1 instead.
647

    
648
Then create a small library that just contains llrint():
649

    
650
@example
651
ar x /usr/lib/mingw/libmingwex.a llrint.o
652
ar cq /usr/local/lib/libllrint.a llrint.o
653
@end example
654

    
655
Then run
656

    
657
@example
658
./configure --enable-static --disable-shared  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
659
@end example
660

    
661
to make a static build or
662

    
663
@example
664
./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
665
@end example
666

    
667
to build shared libraries.
668

    
669
If you want to build FFmpeg with additional libraries, download Cygwin
670
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
671
and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
672
(@url{http://cygwinports.dotsrc.org/}).
673

    
674
@subsection Crosscompilation for Windows under Cygwin
675

    
676
With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
677

    
678
Just install your Cygwin as explained before, plus these additional
679
"Devel" packages:
680
@example
681
gcc-mingw-core, mingw-runtime, mingw-zlib
682
@end example
683

    
684
and add some special flags to your configure invocation.
685

    
686
For a static build run
687
@example
688
./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
689
@end example
690

    
691
and for a build with shared libraries
692
@example
693
./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
694
@end example
695

    
696
@section BeOS
697

    
698
BeOS support is broken in mysterious ways.
699

    
700
@section OS/2
701

    
702
For information about compiling FFmpeg on OS/2 see
703
@url{http://www.edm2.com/index.php/FFmpeg}.
704

    
705
@chapter Developers Guide
706

    
707
@section API
708
@itemize @bullet
709
@item libavcodec is the library containing the codecs (both encoding and
710
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
711

    
712
@item libavformat is the library containing the file format handling (mux and
713
demux code for several formats). Look at @file{ffplay.c} to use it in a
714
player. See @file{output_example.c} to use it to generate audio or video
715
streams.
716

    
717
@end itemize
718

    
719
@section Integrating libavcodec or libavformat in your program
720

    
721
You can integrate all the source code of the libraries to link them
722
statically to avoid any version problem. All you need is to provide a
723
'config.mak' and a 'config.h' in the parent directory. See the defines
724
generated by ./configure to understand what is needed.
725

    
726
You can use libavcodec or libavformat in your commercial program, but
727
@emph{any patch you make must be published}. The best way to proceed is
728
to send your patches to the FFmpeg mailing list.
729

    
730
@node Coding Rules
731
@section Coding Rules
732

    
733
FFmpeg is programmed in the ISO C90 language with a few additional
734
features from ISO C99, namely:
735
@itemize @bullet
736
@item
737
the @samp{inline} keyword;
738
@item
739
@samp{//} comments;
740
@item
741
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
742
@item
743
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
744
@end itemize
745

    
746
These features are supported by all compilers we care about, so we will not
747
accept patches to remove their use unless they absolutely do not impair
748
clarity and performance.
749

    
750
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
751
compiles with several other compilers, such as the Compaq ccc compiler
752
or Sun Studio 9, and we would like to keep it that way unless it would
753
be exceedingly involved. To ensure compatibility, please do not use any
754
additional C99 features or GCC extensions. Especially watch out for:
755
@itemize @bullet
756
@item
757
mixing statements and declarations;
758
@item
759
@samp{long long} (use @samp{int64_t} instead);
760
@item
761
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
762
@item
763
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
764
@end itemize
765

    
766
Indent size is 4.
767
The presentation is the one specified by 'indent -i4 -kr -nut'.
768
The TAB character is forbidden outside of Makefiles as is any
769
form of trailing whitespace. Commits containing either will be
770
rejected by the Subversion repository.
771

    
772
The main priority in FFmpeg is simplicity and small code size in order to
773
minimize the bug count.
774

    
775
Comments: Use the JavaDoc/Doxygen
776
format (see examples below) so that code documentation
777
can be generated automatically. All nontrivial functions should have a comment
778
above them explaining what the function does, even if it is just one sentence.
779
All structures and their member variables should be documented, too.
780
@example
781
/**
782
 * @@file mpeg.c
783
 * MPEG codec.
784
 * @@author ...
785
 */
786

    
787
/**
788
 * Summary sentence.
789
 * more text ...
790
 * ...
791
 */
792
typedef struct Foobar@{
793
    int var1; /**< var1 description */
794
    int var2; ///< var2 description
795
    /** var3 description */
796
    int var3;
797
@} Foobar;
798

    
799
/**
800
 * Summary sentence.
801
 * more text ...
802
 * ...
803
 * @@param my_parameter description of my_parameter
804
 * @@return return value description
805
 */
806
int myfunc(int my_parameter)
807
...
808
@end example
809

    
810
fprintf and printf are forbidden in libavformat and libavcodec,
811
please use av_log() instead.
812

    
813
Casts should be used only when necessary. Unneeded parentheses
814
should also be avoided if they don't make the code easier to understand.
815

    
816
@section Development Policy
817

    
818
@enumerate
819
@item
820
   Contributions should be licensed under the LGPL 2.1, including an
821
   "or any later version" clause, or the MIT license.  GPL 2 including
822
   an "or any later version" clause is also acceptable, but LGPL is
823
   preferred.
824
@item
825
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
826
   enabled code which breaks compilation or compiles but does not work or
827
   breaks the regression tests)
828
   You can commit unfinished stuff (for testing etc), but it must be disabled
829
   (#ifdef etc) by default so it does not interfere with other developers'
830
   work.
831
@item
832
   You do not have to over-test things. If it works for you, and you think it
833
   should work for others, then commit. If your code has problems
834
   (portability, triggers compiler bugs, unusual environment etc) they will be
835
   reported and eventually fixed.
836
@item
837
   Do not commit unrelated changes together, split them into self-contained
838
   pieces. Also do not forget that if part B depends on part A, but A does not
839
   depend on B, then A can and should be committed first and separate from B.
840
   Keeping changes well split into self-contained parts makes reviewing and
841
   understanding them on the commit log mailing list easier. This also helps
842
   in case of debugging later on.
843
   Also if you have doubts about splitting or not splitting, do not hesitate to
844
   ask/discuss it on the developer mailing list.
845
@item
846
   Do not change behavior of the program (renaming options etc) without
847
   first discussing it on the ffmpeg-devel mailing list. Do not remove
848
   functionality from the code. Just improve!
849

    
850
   Note: Redundant code can be removed.
851
@item
852
   Do not commit changes to the build system (Makefiles, configure script)
853
   which change behavior, defaults etc, without asking first. The same
854
   applies to compiler warning fixes, trivial looking fixes and to code
855
   maintained by other developers. We usually have a reason for doing things
856
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
857
   list, and if the code maintainers say OK, you may commit. This does not
858
   apply to files you wrote and/or maintain.
859
@item
860
   We refuse source indentation and other cosmetic changes if they are mixed
861
   with functional changes, such commits will be rejected and removed. Every
862
   developer has his own indentation style, you should not change it. Of course
863
   if you (re)write something, you can use your own style, even though we would
864
   prefer if the indentation throughout FFmpeg was consistent (Many projects
865
   force a given indentation style - we do not.). If you really need to make
866
   indentation changes (try to avoid this), separate them strictly from real
867
   changes.
868

    
869
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
870
   then either do NOT change the indentation of the inner part within (do not
871
   move it to the right)! or do so in a separate commit
872
@item
873
   Always fill out the commit log message. Describe in a few lines what you
874
   changed and why. You can refer to mailing list postings if you fix a
875
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
876
@item
877
   If you apply a patch by someone else, include the name and email address in
878
   the log message. Since the ffmpeg-cvslog mailing list is publicly
879
   archived you should add some SPAM protection to the email address. Send an
880
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
881
   you applied the patch.
882
@item
883
   When applying patches that have been discussed (at length) on the mailing
884
   list, reference the thread in the log message.
885
@item
886
    Do NOT commit to code actively maintained by others without permission.
887
    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
888
    timeframe (12h for build failures and security fixes, 3 days small changes,
889
    1 week for big patches) then commit your patch if you think it is OK.
890
    Also note, the maintainer can simply ask for more time to review!
891
@item
892
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
893
    are sent there and reviewed by all the other developers. Bugs and possible
894
    improvements or general questions regarding commits are discussed there. We
895
    expect you to react if problems with your code are uncovered.
896
@item
897
    Update the documentation if you change behavior or add features. If you are
898
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
899
    maintainer(s) will review and commit your stuff.
900
@item
901
    Try to keep important discussions and requests (also) on the public
902
    developer mailing list, so that all developers can benefit from them.
903
@item
904
    Never write to unallocated memory, never write over the end of arrays,
905
    always check values read from some untrusted source before using them
906
    as array index or other risky things.
907
@item
908
    Remember to check if you need to bump versions for the specific libav
909
    parts (libavutil, libavcodec, libavformat) you are changing. You need
910
    to change the version integer.
911
    Incrementing the first component means no backward compatibility to
912
    previous versions (e.g. removal of a function from the public API).
913
    Incrementing the second component means backward compatible change
914
    (e.g. addition of a function to the public API or extension of an
915
    existing data structure).
916
    Incrementing the third component means a noteworthy binary compatible
917
    change (e.g. encoder bug fix that matters for the decoder).
918
@item
919
    Compiler warnings indicate potential bugs or code with bad style. If a type of
920
    warning always points to correct and clean code, that warning should
921
    be disabled, not the code changed.
922
    Thus the remaining warnings can either be bugs or correct code.
923
    If it is a bug, the bug has to be fixed. If it is not, the code should
924
    be changed to not generate a warning unless that causes a slowdown
925
    or obfuscates the code.
926
@item
927
    If you add a new file, give it a proper license header. Do not copy and
928
    paste it from a random place, use an existing file as template.
929
@end enumerate
930

    
931
We think our rules are not too hard. If you have comments, contact us.
932

    
933
Note, these rules are mostly borrowed from the MPlayer project.
934

    
935
@section Submitting patches
936

    
937
First, (@pxref{Coding Rules}) above if you did not yet.
938

    
939
When you submit your patch, try to send a unified diff (diff '-up'
940
option). We cannot read other diffs :-)
941

    
942
Also please do not submit a patch which contains several unrelated changes.
943
Split it into separate, self-contained pieces. This does not mean splitting
944
file by file. Instead, make the patch as small as possible while still
945
keeping it as a logical unit that contains an individual change, even
946
if it spans multiple files. This makes reviewing your patches much easier
947
for us and greatly increases your chances of getting your patch applied.
948

    
949
Run the regression tests before submitting a patch so that you can
950
verify that there are no big problems.
951

    
952
Patches should be posted as base64 encoded attachments (or any other
953
encoding which ensures that the patch will not be trashed during
954
transmission) to the ffmpeg-devel mailing list, see
955
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
956

    
957
It also helps quite a bit if you tell us what the patch does (for example
958
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
959
and has no lrint()')
960

    
961
Also please if you send several patches, send each patch as a separate mail,
962
do not attach several unrelated patches to the same mail.
963

    
964
@section New codecs or formats checklist
965

    
966
@enumerate
967
@item
968
    Did you use av_cold for codec initialization and close functions?
969
@item
970
    Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
971
    AVInputFormat/AVOutputFormat struct?
972
@item
973
    Did you bump the minor version number in @file{avcodec.h} or
974
    @file{avformat.h}?
975
@item
976
    Did you register it in @file{allcodecs.c} or @file{allformats.c}?
977
@item
978
    Did you add the CodecID to @file{avcodec.h}?
979
@item
980
    If it has a fourcc, did you add it to @file{libavformat/riff.c},
981
    even if it is only a decoder?
982
@item
983
    Did you add a rule to compile the appropriate files in the Makefile?
984
    Remember to do this even if you're just adding a format to a file that is
985
    already being compiled by some other rule, like a raw demuxer.
986
@item
987
    Did you add an entry to the table of supported formats or codecs in the
988
    documentation?
989
@item
990
    Did you add an entry in the Changelog?
991
@item
992
    If it depends on a parser or a library, did you add that dependency in
993
    configure?
994
@item
995
    Did you "svn add" the appropriate files before commiting?
996
@end enumerate
997

    
998
@section patch submission checklist
999

    
1000
@enumerate
1001
@item
1002
    Do the regression tests pass with the patch applied?
1003
@item
1004
    Is the patch a unified diff?
1005
@item
1006
    Is the patch against latest FFmpeg SVN?
1007
@item
1008
    Are you subscribed to ffmpeg-dev?
1009
    (the list is subscribers only due to spam)
1010
@item
1011
    Have you checked that the changes are minimal, so that the same cannot be
1012
    achieved with a smaller patch and/or simpler final code?
1013
@item
1014
    If the change is to speed critical code, did you benchmark it?
1015
@item
1016
    If you did any benchmarks, did you provide them in the mail?
1017
@item
1018
    Have you checked that the patch does not introduce buffer overflows or
1019
    other security issues?
1020
@item
1021
    If you add a new demuxer or decoder, have you checked that it does not
1022
    crash with damaged input (see tools/trasher)?
1023
@item
1024
    Is the patch created from the root of the source tree, so it can be
1025
    applied with @code{patch -p0}?
1026
@item
1027
    Does the patch not mix functional and cosmetic changes?
1028
@item
1029
    Did you add tabs or trailing whitespace to the code? Both are forbidden.
1030
@item
1031
    Is the patch attached to the email you send?
1032
@item
1033
    Is the mime type of the patch correct? It should be text/x-diff or
1034
    text/x-patch or at least text/plain and not application/octet-stream.
1035
@item
1036
    If the patch fixes a bug, did you provide a verbose analysis of the bug?
1037
@item
1038
    If the patch fixes a bug, did you provide enough information, including
1039
    a sample, so the bug can be reproduced and the fix can be verified?
1040
    Note please do not attach samples >100k to mails but rather provide a
1041
    URL, you can upload to ftp://upload.mplayerhq.hu
1042
@item
1043
    Did you provide a verbose summary about what the patch does change?
1044
@item
1045
    Did you provide a verbose explanation why it changes things like it does?
1046
@item
1047
    Did you provide a verbose summary of the user visible advantages and
1048
    disadvantages if the patch is applied?
1049
@item
1050
    Did you provide an example so we can verify the new feature added by the
1051
    patch easily?
1052
@item
1053
    If you added a new file, did you insert a license header? It should be
1054
    taken from FFmpeg, not randomly copied and pasted from somewhere else.
1055
@item
1056
    You should maintain alphabetical order in alphabetically ordered lists as
1057
    long as doing so does not break API/ABI compatibility.
1058
@item
1059
    Lines with similar content should be aligned vertically when doing so
1060
    improves readability.
1061
@item
1062
    Did you provide a suggestion for a clear commit log message?
1063
@item
1064
    Did you test your decoder or demuxer against damaged data? If no, see
1065
    tools/trasher and the noise bitstream filter. Your decoder or demuxer
1066
    should not crash or end in a (near) infinite loop when fed damaged data.
1067
@end enumerate
1068

    
1069
@section Patch review process
1070

    
1071
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1072
clear note that the patch is not for SVN.
1073
Reviews and comments will be posted as replies to the patch on the
1074
mailing list. The patch submitter then has to take care of every comment,
1075
that can be by resubmitting a changed patch or by discussion. Resubmitted
1076
patches will themselves be reviewed like any other patch. If at some point
1077
a patch passes review with no comments then it is approved, that can for
1078
simple and small patches happen immediately while large patches will generally
1079
have to be changed and reviewed many times before they are approved.
1080
After a patch is approved it will be committed to the repository.
1081

    
1082
We will review all submitted patches, but sometimes we are quite busy so
1083
especially for large patches this can take several weeks.
1084

    
1085
When resubmitting patches, please do not make any significant changes
1086
not related to the comments received during review. Such patches will
1087
be rejected. Instead, submit  significant changes or new features as
1088
separate patches.
1089

    
1090
@section Regression tests
1091

    
1092
Before submitting a patch (or committing to the repository), you should at least
1093
test that you did not break anything.
1094

    
1095
The regression tests build a synthetic video stream and a synthetic
1096
audio stream. These are then encoded and decoded with all codecs or
1097
formats. The CRC (or MD5) of each generated file is recorded in a
1098
result file. A 'diff' is launched to compare the reference results and
1099
the result file.
1100

    
1101
The regression tests then go on to test the FFserver code with a
1102
limited set of streams. It is important that this step runs correctly
1103
as well.
1104

    
1105
Run 'make test' to test all the codecs and formats.
1106

    
1107
Run 'make fulltest' to test all the codecs, formats and FFserver.
1108

    
1109
[Of course, some patches may change the results of the regression tests. In
1110
this case, the reference results of the regression tests shall be modified
1111
accordingly].
1112

    
1113
@bye