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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 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 ASF@tab X @tab X
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@item AVI@tab X @tab X
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@item WAV@tab X @tab X
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@item Macromedia Flash@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 FLV              @tab  X @tab X
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@tab Macromedia Flash video files
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@item Real Audio and Video @tab X @tab X
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@item Raw AC3 @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 PCM8/16 bits, mulaw/Alaw@tab X  @tab  X
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@item Raw CRI ADX audio @tab X  @tab  X
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@item Raw Shorten audio @tab    @tab  X
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@item SUN AU format @tab X  @tab  X
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@item NUT @tab X @tab X @tab NUT Open Container Format
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@item QuickTime        @tab X @tab  X
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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 Raw MPEG4 video  @tab  X @tab  X
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@item DV               @tab  X @tab  X
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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 Playstation STR  @tab    @tab X
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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 Interplay MVE    @tab    @tab X
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@tab Format used in various Interplay computer games.
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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 Sega FILM/CPK    @tab    @tab X
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@tab Used in many Sega Saturn console games.
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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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@item Id Cinematic (.cin) @tab    @tab X
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@tab Used in Quake II.
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@item FLIC format      @tab    @tab X
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@tab .fli/.flc files
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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 Sierra Online    @tab    @tab X
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@tab .sol files used in Sierra Online games.
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@item Matroska         @tab X  @tab X
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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 MAXIS EA XA      @tab    @tab X
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@tab Used in Sim City 3000; file extension .xa.
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@item Nullsoft Video (NSV) format @tab    @tab X
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@item ADTS AAC audio @tab X @tab X
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@item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
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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 AVS @tab    @tab X
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@tab Multimedia format used by the Creature Shock game.
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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 GXF @tab  X @tab X
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@tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
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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 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 SEQ @tab    @tab X
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@tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
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@item DXA @tab    @tab X
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@tab This format is used in non-Windows version of Feeble Files game and
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different game cutscenes repacked for use with ScummVM.
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@item THP @tab    @tab X
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@tab Used on the Nintendo GameCube.
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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 Bethsoft VID @tab    @tab X
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@tab Used in some games from Bethesda Softworks.
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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 Monkey's Audio @tab    @tab X
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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 LMLM4 @tab    @tab X
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@tab Used by Linux Media Labs MPEG-4 PCI boards
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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 MSN TCP Webcam @tab    @tab X
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@tab Used by MSN Messenger Webcam streams.
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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 IFF @tab    @tab X
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@tab Interchange File Format
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@item BFI @tab    @tab
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@tab Brute Force & Ignorance, used in Flash Traffic: City of Angels
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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 PGM, PPM     @tab X @tab X
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@item PAM          @tab X @tab X @tab PAM is a PNM extension with alpha support.
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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 JPEG         @tab X @tab X @tab Progressive JPEG is not supported.
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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 PNG          @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
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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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@item SGI          @tab X @tab X @tab SGI RGB image format
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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 PCX          @tab   @tab X @tab PC Paintbrush
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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 MPEG-1 video           @tab  X  @tab  X
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@item MPEG-2 video           @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 WMV7                   @tab  X  @tab  X
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@item WMV8                   @tab  X  @tab  X @tab not completely working
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@item WMV9                   @tab     @tab  X @tab not completely working
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@item VC1                    @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 @tab also known as RealVideo 1.0
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@item H.264                  @tab     @tab  X
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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 MJPEG                  @tab  X  @tab  X
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@item lossless MJPEG         @tab  X  @tab  X
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@item JPEG-LS                @tab  X  @tab  X @tab fourcc: MJLS, lossless and near-lossless is supported
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@item Apple MJPEG-B          @tab     @tab  X
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@item Sunplus MJPEG          @tab     @tab  X @tab fourcc: SP5X
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@item DV                     @tab  X  @tab  X
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@item HuffYUV                @tab  X  @tab  X
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@item FFmpeg Video 1         @tab  X  @tab  X @tab experimental lossless codec (fourcc: FFV1)
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@item FFmpeg Snow            @tab  X  @tab  X @tab experimental wavelet codec (fourcc: SNOW)
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@item Asus v1                @tab  X  @tab  X @tab fourcc: ASV1
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@item Asus v2                @tab  X  @tab  X @tab fourcc: ASV2
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@item Creative YUV           @tab     @tab  X @tab fourcc: CYUV
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@item Sorenson Video 1       @tab  X  @tab  X @tab fourcc: SVQ1
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@item Sorenson Video 3       @tab     @tab  X @tab fourcc: SVQ3
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@item On2 VP3                @tab     @tab  X @tab still experimental
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@item On2 VP5                @tab     @tab  X @tab fourcc: VP50
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@item On2 VP6                @tab     @tab  X @tab fourcc: VP60,VP61,VP62
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@item Theora                 @tab  X  @tab  X @tab still experimental
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@item Intel Indeo 3          @tab     @tab  X
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@item FLV                    @tab  X  @tab  X @tab Sorenson H.263 used in Flash
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@item Flash Screen Video     @tab  X  @tab  X @tab fourcc: FSV1
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@item ATI VCR1               @tab     @tab  X @tab fourcc: VCR1
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@item ATI VCR2               @tab     @tab  X @tab fourcc: VCR2
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@item Cirrus Logic AccuPak   @tab     @tab  X @tab fourcc: CLJR
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@item 4X Video               @tab     @tab  X @tab Used in certain computer games.
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@item Sony Playstation MDEC  @tab     @tab  X
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@item Id RoQ                 @tab  X  @tab  X @tab Used in Quake III, Jedi Knight 2, other computer games.
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@item Xan/WC3                @tab     @tab  X @tab Used in Wing Commander III .MVE files.
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@item Interplay Video        @tab     @tab  X @tab Used in Interplay .MVE files.
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@item Apple Animation        @tab  X  @tab  X @tab fourcc: 'rle '
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@item Apple Graphics         @tab     @tab  X @tab fourcc: 'smc '
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@item Apple Video            @tab     @tab  X @tab fourcc: rpza
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@item Apple QuickDraw        @tab     @tab  X @tab fourcc: qdrw
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@item Cinepak                @tab     @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 Westwood VQA           @tab     @tab  X
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@item Id Cinematic Video     @tab     @tab  X @tab Used in Quake II.
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@item Planar RGB             @tab     @tab  X @tab fourcc: 8BPS
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@item FLIC video             @tab     @tab  X
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@item Duck TrueMotion v1     @tab     @tab  X @tab fourcc: DUCK
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@item Duck TrueMotion v2     @tab     @tab  X @tab fourcc: TM20
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@item VMD Video              @tab     @tab  X @tab Used in Sierra VMD files.
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@item MSZH                   @tab     @tab  X @tab Part of LCL
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@item ZLIB                   @tab  X  @tab  X @tab Part of LCL, encoder experimental
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@item TechSmith Camtasia     @tab     @tab  X @tab fourcc: TSCC
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@item IBM Ultimotion         @tab     @tab  X @tab fourcc: ULTI
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@item Miro VideoXL           @tab     @tab  X @tab fourcc: VIXL
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@item QPEG                   @tab     @tab  X @tab fourccs: QPEG, Q1.0, Q1.1
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@item LOCO                   @tab     @tab  X @tab
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@item Winnov WNV1            @tab     @tab  X @tab
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@item Autodesk Animator Studio Codec  @tab     @tab  X @tab fourcc: AASC
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@item Fraps FPS1             @tab     @tab  X @tab
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@item CamStudio              @tab     @tab  X @tab fourcc: CSCD
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@item American Laser Games Video  @tab    @tab X @tab Used in games like Mad Dog McCree
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@item ZMBV                   @tab   X @tab  X @tab Encoder works only on PAL8
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@item AVS Video              @tab     @tab  X @tab Video encoding used by the Creature Shock game.
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@item Smacker Video          @tab     @tab  X @tab Video encoding used in Smacker.
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@item RTjpeg                 @tab     @tab  X @tab Video encoding used in NuppelVideo files.
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@item KMVC                   @tab     @tab  X @tab Codec used in Worms games.
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@item VMware Video           @tab     @tab  X @tab Codec used in videos captured by VMware.
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@item Cin Video              @tab     @tab  X @tab Codec used in Delphine Software games.
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@item Tiertex Seq Video      @tab     @tab  X @tab Codec used in DOS CDROM FlashBack game.
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@item DXA Video              @tab     @tab  X @tab Codec originally used in Feeble Files game.
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@item AVID DNxHD             @tab   X @tab  X @tab aka SMPTE VC3
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@item C93 Video              @tab     @tab  X @tab Codec used in Cyberia game.
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@item THP                    @tab     @tab  X @tab Used on the Nintendo GameCube.
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@item Bethsoft VID           @tab     @tab  X @tab Used in some games from Bethesda Softworks.
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@item Renderware TXD         @tab     @tab  X @tab Texture dictionaries used by the Renderware Engine.
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@item AMV                    @tab     @tab  X @tab Used in Chinese MP3 players.
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@item Mimic                  @tab     @tab  X @tab Used in MSN Messenger Webcam streams.
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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 MPEG audio layer 2     @tab  IX  @tab  IX
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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 AC3                    @tab  IX  @tab  IX
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@tab liba52 is used internally for decoding.
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@item Vorbis                 @tab  X   @tab  X
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@item WMA V1/V2              @tab X    @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 Microsoft ADPCM        @tab X    @tab X
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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 MS IMA ADPCM           @tab X    @tab X
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@item QT IMA ADPCM           @tab X    @tab X
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@item 4X IMA ADPCM           @tab      @tab X
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@item G.726  ADPCM           @tab X    @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 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 SMJPEG IMA ADPCM       @tab      @tab X
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@tab Used in certain Loki game ports.
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@item CD-ROM XA ADPCM        @tab      @tab X
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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 Electronic Arts ADPCM  @tab      @tab X
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@tab Used in various EA titles.
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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 Creative ADPCM         @tab      @tab X
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@tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
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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 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 AC3 codec, liba52 is used 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 DV audio               @tab      @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 Interplay MVE DPCM     @tab      @tab X
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@tab Used in various Interplay computer games.
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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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@item Sierra Online DPCM     @tab      @tab X
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@tab Used in Sierra Online game audio files.
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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 FLAC lossless audio    @tab X    @tab X
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@item Shorten lossless audio @tab      @tab X
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@item Apple lossless audio   @tab      @tab X
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@tab QuickTime fourcc 'alac'
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@item FFmpeg Sonic           @tab X    @tab X
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@tab experimental lossy/lossless codec
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@item Qdesign QDM2           @tab      @tab X
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@tab there are still some distortions
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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 DSP Group TrueSpeech   @tab      @tab X
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@item True Audio (TTA)       @tab      @tab X
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@item Smacker Audio          @tab      @tab X
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@item WavPack Audio          @tab      @tab X
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@item Cin Audio              @tab      @tab X
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@tab Codec used in Delphine Software games.
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@item Intel Music Coder      @tab      @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 DT$ Coherent Audio     @tab      @tab X
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@item ATRAC 3                @tab      @tab X
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@item Monkey's Audio         @tab      @tab X @tab Only versions 3.97-3.99 are supported
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@item Nellymoser ASAO        @tab      @tab X
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@item 8SVX Audio             @tab      @tab X
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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. 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 The target @code{make wininstaller} can be used to create a
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Nullsoft-based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
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must be copied to the FFmpeg directory in order to build the
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installer.
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@item By using @code{./configure --enable-shared} when configuring FFmpeg,
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you can build libavutil, libavcodec and libavformat as DLLs.
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@end itemize
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@subsection Microsoft Visual C++ compatibility
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As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
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want to use the libav* libraries in your own applications, you can still
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compile those applications using MSVC++. But the libav* libraries you link
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to @emph{must} be built with MinGW. However, you will not be able to debug
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inside the libav* libraries, since MSVC++ does not recognize the debug
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symbols generated by GCC.
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We strongly recommend you to move over from MSVC++ to MinGW tools.
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This description of how to use the FFmpeg libraries with MSVC++ is based on
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Microsoft Visual C++ 2005 Express Edition. If you have a different version,
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you might have to modify the procedures slightly.
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@subsubsection Using static libraries
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Assuming you have just built and installed FFmpeg in @file{/usr/local}.
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@enumerate
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@item Create a new console application ("File / New / Project") and then
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select "Win32 Console Application". On the appropriate page of the
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Application Wizard, uncheck the "Precompiled headers" option.
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@item Write the source code for your application, or, for testing, just
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copy the code from an existing sample application into the source file
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that MSVC++ has already created for you. For example, you can copy
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@file{output_example.c} from the FFmpeg distribution.
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@item Open the "Project / Properties" dialog box. In the "Configuration"
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combo box, select "All Configurations" so that the changes you make will
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affect both debug and release builds. In the tree view on the left hand
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side, select "C/C++ / General", then edit the "Additional Include
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Directories" setting to contain the path where the FFmpeg includes were
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installed (i.e. @file{c:\msys\1.0\local\include}).
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@item Still in the "Project / Properties" dialog box, select
451
"Linker / General" from the tree view and edit the
452
"Additional Library Directories" setting to contain the @file{lib}
453
directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
454
the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
455
and the directory where MinGW's GCC libs are installed
456
(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
457
"Linker / Input" from the tree view, and add the files @file{libavformat.a},
458
@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
459
@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
460
to the end of "Additional Dependencies".
461

    
462
@item Now, select "C/C++ / Code Generation" from the tree view. Select
463
"Debug" in the "Configuration" combo box. Make sure that "Runtime
464
Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
465
the "Configuration" combo box and make sure that "Runtime Library" is
466
set to "Multi-threaded DLL".
467

    
468
@item Click "OK" to close the "Project / Properties" dialog box.
469

    
470
@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
471
Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
472
and install it in MSVC++'s include directory
473
(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
474

    
475
@item MSVC++ also does not understand the @code{inline} keyword used by
476
FFmpeg, so you must add this line before @code{#include}ing libav*:
477
@example
478
#define inline _inline
479
@end example
480

    
481
@item If you used @file{output_example.c} as your sample application,
482
you will have to edit the @code{#include}s to point to the files which
483
are under the @file{ffmpeg} directory (i.e. @code{<ffmpeg/avformat.h>}).
484

    
485
@item Build your application, everything should work.
486

    
487
@end enumerate
488

    
489
@subsubsection Using shared libraries
490

    
491
This is how to create DLL and LIB files that are compatible with MSVC++:
492

    
493
@enumerate
494

    
495
@item Add a call to @file{vcvars32.bat} (which sets up the environment
496
variables for the Visual C++ tools) as the first line of @file{msys.bat}.
497
The standard location for @file{vcvars32.bat} is
498
@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
499
and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
500
If this corresponds to your setup, add the following line as the first line
501
of @file{msys.bat}:
502

    
503
@example
504
call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
505
@end example
506

    
507
Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
508
and run @file{c:\msys\1.0\msys.bat} from there.
509

    
510
@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
511
from @file{Microsoft (R) Library Manager}, this means your environment
512
variables are set up correctly, the @file{Microsoft (R) Library Manager}
513
is on the path and will be used by FFmpeg to create
514
MSVC++-compatible import libraries.
515

    
516
@item Build FFmpeg with
517

    
518
@example
519
./configure --enable-shared --enable-memalign-hack
520
make
521
make install
522
@end example
523

    
524
Your install path (@file{/usr/local/} by default) should now have the
525
necessary DLL and LIB files under the @file{bin} directory.
526

    
527
@end enumerate
528

    
529
To use those files with MSVC++, do the same as you would do with
530
the static libraries, as described above. But in Step 4,
531
you should only need to add the directory where the LIB files are installed
532
(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
533
installed in the @file{bin} directory. And instead of adding @file{libxx.a}
534
files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
535
@file{avutil.lib}. There should be no need for @file{libmingwex.a},
536
@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
537
statically linked into the DLLs. The @file{bin} directory contains a bunch
538
of DLL files, but the ones that are actually used to run your application
539
are the ones with a major version number in their filenames
540
(i.e. @file{avcodec-51.dll}).
541

    
542
@subsection Cross compilation for Windows with Linux
543

    
544
You must use the MinGW cross compilation tools available at
545
@url{http://www.mingw.org/}.
546

    
547
Then configure FFmpeg with the following options:
548
@example
549
./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
550
@end example
551
(you can change the cross-prefix according to the prefix chosen for the
552
MinGW tools).
553

    
554
Then you can easily test FFmpeg with Wine
555
(@url{http://www.winehq.com/}).
556

    
557
@subsection Compilation under Cygwin
558

    
559
The main issue with Cygwin is that newlib, its C library, does not
560
contain llrint().  However, it is possible to leverage the
561
implementation in MinGW.
562

    
563
Just install your Cygwin with all the "Base" packages, plus the
564
following "Devel" ones:
565
@example
566
binutils, gcc-core, make, subversion, mingw-runtime
567
@end example
568

    
569
Do not install binutils-20060709-1 (they are buggy on shared builds);
570
use binutils-20050610-1 instead.
571

    
572
Then create a small library that just contains llrint():
573

    
574
@example
575
ar x /usr/lib/mingw/libmingwex.a llrint.o
576
ar cq /usr/local/lib/libllrint.a llrint.o
577
@end example
578

    
579
Then run
580

    
581
@example
582
./configure --enable-static --disable-shared  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
583
@end example
584

    
585
to make a static build or
586

    
587
@example
588
./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
589
@end example
590

    
591
to build shared libraries.
592

    
593
If you want to build FFmpeg with additional libraries, download Cygwin
594
"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
595
and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
596
(@url{http://cygwinports.dotsrc.org/}).
597

    
598
@subsection Crosscompilation for Windows under Cygwin
599

    
600
With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
601

    
602
Just install your Cygwin as explained before, plus these additional
603
"Devel" packages:
604
@example
605
gcc-mingw-core, mingw-runtime, mingw-zlib
606
@end example
607

    
608
and add some special flags to your configure invocation.
609

    
610
For a static build run
611
@example
612
./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
613
@end example
614

    
615
and for a build with shared libraries
616
@example
617
./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
618
@end example
619

    
620
@section BeOS
621

    
622
BeOS support is broken in mysterious ways.
623

    
624
@section OS/2
625

    
626
For information about compiling FFmpeg on OS/2 see
627
@url{http://www.edm2.com/index.php/FFmpeg}.
628

    
629
@chapter Developers Guide
630

    
631
@section API
632
@itemize @bullet
633
@item libavcodec is the library containing the codecs (both encoding and
634
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
635

    
636
@item libavformat is the library containing the file format handling (mux and
637
demux code for several formats). Look at @file{ffplay.c} to use it in a
638
player. See @file{output_example.c} to use it to generate audio or video
639
streams.
640

    
641
@end itemize
642

    
643
@section Integrating libavcodec or libavformat in your program
644

    
645
You can integrate all the source code of the libraries to link them
646
statically to avoid any version problem. All you need is to provide a
647
'config.mak' and a 'config.h' in the parent directory. See the defines
648
generated by ./configure to understand what is needed.
649

    
650
You can use libavcodec or libavformat in your commercial program, but
651
@emph{any patch you make must be published}. The best way to proceed is
652
to send your patches to the FFmpeg mailing list.
653

    
654
@node Coding Rules
655
@section Coding Rules
656

    
657
FFmpeg is programmed in the ISO C90 language with a few additional
658
features from ISO C99, namely:
659
@itemize @bullet
660
@item
661
the @samp{inline} keyword;
662
@item
663
@samp{//} comments;
664
@item
665
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
666
@item
667
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
668
@end itemize
669

    
670
These features are supported by all compilers we care about, so we will not
671
accept patches to remove their use unless they absolutely do not impair
672
clarity and performance.
673

    
674
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
675
compiles with several other compilers, such as the Compaq ccc compiler
676
or Sun Studio 9, and we would like to keep it that way unless it would
677
be exceedingly involved. To ensure compatibility, please do not use any
678
additional C99 features or GCC extensions. Especially watch out for:
679
@itemize @bullet
680
@item
681
mixing statements and declarations;
682
@item
683
@samp{long long} (use @samp{int64_t} instead);
684
@item
685
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
686
@item
687
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
688
@end itemize
689

    
690
Indent size is 4.
691
The presentation is the one specified by 'indent -i4 -kr -nut'.
692
The TAB character is forbidden outside of Makefiles as is any
693
form of trailing whitespace. Commits containing either will be
694
rejected by the Subversion repository.
695

    
696
The main priority in FFmpeg is simplicity and small code size in order to
697
minimize the bug count.
698

    
699
Comments: Use the JavaDoc/Doxygen
700
format (see examples below) so that code documentation
701
can be generated automatically. All nontrivial functions should have a comment
702
above them explaining what the function does, even if it is just one sentence.
703
All structures and their member variables should be documented, too.
704
@example
705
/**
706
 * @@file mpeg.c
707
 * MPEG codec.
708
 * @@author ...
709
 */
710

    
711
/**
712
 * Summary sentence.
713
 * more text ...
714
 * ...
715
 */
716
typedef struct Foobar@{
717
    int var1; /**< var1 description */
718
    int var2; ///< var2 description
719
    /** var3 description */
720
    int var3;
721
@} Foobar;
722

    
723
/**
724
 * Summary sentence.
725
 * more text ...
726
 * ...
727
 * @@param my_parameter description of my_parameter
728
 * @@return return value description
729
 */
730
int myfunc(int my_parameter)
731
...
732
@end example
733

    
734
fprintf and printf are forbidden in libavformat and libavcodec,
735
please use av_log() instead.
736

    
737
Casts should be used only when necessary. Unneeded parentheses
738
should also be avoided if they don't make the code easier to understand.
739

    
740
@section Development Policy
741

    
742
@enumerate
743
@item
744
   Contributions should be licensed under the LGPL 2.1, including an
745
   "or any later version" clause, or the MIT license.  GPL 2 including
746
   an "or any later version" clause is also acceptable, but LGPL is
747
   preferred.
748
@item
749
   You must not commit code which breaks FFmpeg! (Meaning unfinished but
750
   enabled code which breaks compilation or compiles but does not work or
751
   breaks the regression tests)
752
   You can commit unfinished stuff (for testing etc), but it must be disabled
753
   (#ifdef etc) by default so it does not interfere with other developers'
754
   work.
755
@item
756
   You do not have to over-test things. If it works for you, and you think it
757
   should work for others, then commit. If your code has problems
758
   (portability, triggers compiler bugs, unusual environment etc) they will be
759
   reported and eventually fixed.
760
@item
761
   Do not commit unrelated changes together, split them into self-contained
762
   pieces. Also do not forget that if part B depends on part A, but A does not
763
   depend on B, then A can and should be committed first and separate from B.
764
   Keeping changes well split into self-contained parts makes reviewing and
765
   understanding them on the commit log mailing list easier. This also helps
766
   in case of debugging later on.
767
   Also if you have doubts about splitting or not splitting, do not hesitate to
768
   ask/discuss it on the developer mailing list.
769
@item
770
   Do not change behavior of the program (renaming options etc) without
771
   first discussing it on the ffmpeg-devel mailing list. Do not remove
772
   functionality from the code. Just improve!
773

    
774
   Note: Redundant code can be removed.
775
@item
776
   Do not commit changes to the build system (Makefiles, configure script)
777
   which change behavior, defaults etc, without asking first. The same
778
   applies to compiler warning fixes, trivial looking fixes and to code
779
   maintained by other developers. We usually have a reason for doing things
780
   the way we do. Send your changes as patches to the ffmpeg-devel mailing
781
   list, and if the code maintainers say OK, you may commit. This does not
782
   apply to files you wrote and/or maintain.
783
@item
784
   We refuse source indentation and other cosmetic changes if they are mixed
785
   with functional changes, such commits will be rejected and removed. Every
786
   developer has his own indentation style, you should not change it. Of course
787
   if you (re)write something, you can use your own style, even though we would
788
   prefer if the indentation throughout FFmpeg was consistent (Many projects
789
   force a given indentation style - we do not.). If you really need to make
790
   indentation changes (try to avoid this), separate them strictly from real
791
   changes.
792

    
793
   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
794
   then either do NOT change the indentation of the inner part within (do not
795
   move it to the right)! or do so in a separate commit
796
@item
797
   Always fill out the commit log message. Describe in a few lines what you
798
   changed and why. You can refer to mailing list postings if you fix a
799
   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
800
@item
801
   If you apply a patch by someone else, include the name and email address in
802
   the log message. Since the ffmpeg-cvslog mailing list is publicly
803
   archived you should add some SPAM protection to the email address. Send an
804
   answer to ffmpeg-devel (or wherever you got the patch from) saying that
805
   you applied the patch.
806
@item
807
   When applying patches that have been discussed (at length) on the mailing
808
   list, reference the thread in the log message.
809
@item
810
    Do NOT commit to code actively maintained by others without permission.
811
    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
812
    timeframe (12h for build failures and security fixes, 3 days small changes,
813
    1 week for big patches) then commit your patch if you think it is OK.
814
    Also note, the maintainer can simply ask for more time to review!
815
@item
816
    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
817
    are sent there and reviewed by all the other developers. Bugs and possible
818
    improvements or general questions regarding commits are discussed there. We
819
    expect you to react if problems with your code are uncovered.
820
@item
821
    Update the documentation if you change behavior or add features. If you are
822
    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
823
    maintainer(s) will review and commit your stuff.
824
@item
825
    Try to keep important discussions and requests (also) on the public
826
    developer mailing list, so that all developers can benefit from them.
827
@item
828
    Never write to unallocated memory, never write over the end of arrays,
829
    always check values read from some untrusted source before using them
830
    as array index or other risky things.
831
@item
832
    Remember to check if you need to bump versions for the specific libav
833
    parts (libavutil, libavcodec, libavformat) you are changing. You need
834
    to change the version integer and the version string.
835
    Incrementing the first component means no backward compatibility to
836
    previous versions (e.g. removal of a function from the public API).
837
    Incrementing the second component means backward compatible change
838
    (e.g. addition of a function to the public API).
839
    Incrementing the third component means a noteworthy binary compatible
840
    change (e.g. encoder bug fix that matters for the decoder).
841
@item
842
    If you add a new codec, remember to update the changelog, add it to
843
    the supported codecs table in the documentation and bump the second
844
    component of the @file{libavcodec} version number appropriately. If
845
    it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
846
    is only a decoder.
847
@item
848
    Compiler warnings indicate potential bugs or code with bad style. If a type of
849
    warning always points to correct and clean code, that warning should
850
    be disabled, not the code changed.
851
    Thus the remaining warnings can either be bugs or correct code.
852
    If it is a bug, the bug has to be fixed. If it is not, the code should
853
    be changed to not generate a warning unless that causes a slowdown
854
    or obfuscates the code.
855
@item
856
    If you add a new file, give it a proper license header. Do not copy and
857
    paste it from a random place, use an existing file as template.
858
@end enumerate
859

    
860
We think our rules are not too hard. If you have comments, contact us.
861

    
862
Note, these rules are mostly borrowed from the MPlayer project.
863

    
864
@section Submitting patches
865

    
866
First, (@pxref{Coding Rules}) above if you did not yet.
867

    
868
When you submit your patch, try to send a unified diff (diff '-up'
869
option). We cannot read other diffs :-)
870

    
871
Also please do not submit a patch which contains several unrelated changes.
872
Split it into separate, self-contained pieces. This does not mean splitting
873
file by file. Instead, make the patch as small as possible while still
874
keeping it as a logical unit that contains an individual change, even
875
if it spans multiple files. This makes reviewing your patches much easier
876
for us and greatly increases your chances of getting your patch applied.
877

    
878
Run the regression tests before submitting a patch so that you can
879
verify that there are no big problems.
880

    
881
Patches should be posted as base64 encoded attachments (or any other
882
encoding which ensures that the patch will not be trashed during
883
transmission) to the ffmpeg-devel mailing list, see
884
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
885

    
886
It also helps quite a bit if you tell us what the patch does (for example
887
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
888
and has no lrint()')
889

    
890
Also please if you send several patches, send each patch as a separate mail,
891
do not attach several unrelated patches to the same mail.
892

    
893
@section patch submission checklist
894

    
895
@enumerate
896
@item
897
    Do the regression tests pass with the patch applied?
898
@item
899
    Is the patch a unified diff?
900
@item
901
    Is the patch against latest FFmpeg SVN?
902
@item
903
    Are you subscribed to ffmpeg-dev?
904
    (the list is subscribers only due to spam)
905
@item
906
    Have you checked that the changes are minimal, so that the same cannot be
907
    achieved with a smaller patch and/or simpler final code?
908
@item
909
    If the change is to speed critical code, did you benchmark it?
910
@item
911
    If you did any benchmarks, did you provide them in the mail?
912
@item
913
    Have you checked that the patch does not introduce buffer overflows or
914
    other security issues?
915
@item
916
    If you add a new demuxer or decoder, have you checked that it does not
917
    crash with damaged input (see tools/trasher)?
918
@item
919
    Is the patch created from the root of the source tree, so it can be
920
    applied with @code{patch -p0}?
921
@item
922
    Does the patch not mix functional and cosmetic changes?
923
@item
924
    Did you add tabs or trailing whitespace to the code? Both are forbidden.
925
@item
926
    Is the patch attached to the email you send?
927
@item
928
    Is the mime type of the patch correct? It should be text/x-diff or
929
    text/x-patch or at least text/plain and not application/octet-stream.
930
@item
931
    If the patch fixes a bug, did you provide a verbose analysis of the bug?
932
@item
933
    If the patch fixes a bug, did you provide enough information, including
934
    a sample, so the bug can be reproduced and the fix can be verified?
935
    Note please do not attach samples >100k to mails but rather provide a
936
    URL, you can upload to ftp://upload.mplayerhq.hu
937
@item
938
    Did you provide a verbose summary about what the patch does change?
939
@item
940
    Did you provide a verbose explanation why it changes things like it does?
941
@item
942
    Did you provide a verbose summary of the user visible advantages and
943
    disadvantages if the patch is applied?
944
@item
945
    Did you provide an example so we can verify the new feature added by the
946
    patch easily?
947
@item
948
    If you added a new file, did you insert a license header? It should be
949
    taken from FFmpeg, not randomly copied and pasted from somewhere else.
950
@item
951
    You should maintain alphabetical order in alphabetically ordered lists as
952
    long as doing so does not break API/ABI compatibility.
953
@item
954
    Lines with similar content should be aligned vertically when doing so
955
    improves readability.
956
@item
957
    Did you provide a suggestion for a clear commit log message?
958
@item
959
    Did you test your decoder or demuxer against damaged data? If no, see
960
    tools/trasher and the noise bitstream filter. Your decoder or demuxer
961
    should not crash or end in a (near) infinite loop when fed damaged data.
962
@end enumerate
963

    
964
@section Patch review process
965

    
966
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
967
clear note that the patch is not for SVN.
968
Reviews and comments will be posted as replies to the patch on the
969
mailing list. The patch submitter then has to take care of every comment,
970
that can be by resubmitting a changed patch or by discussion. Resubmitted
971
patches will themselves be reviewed like any other patch. If at some point
972
a patch passes review with no comments then it is approved, that can for
973
simple and small patches happen immediately while large patches will generally
974
have to be changed and reviewed many times before they are approved.
975
After a patch is approved it will be committed to the repository.
976

    
977
We will review all submitted patches, but sometimes we are quite busy so
978
especially for large patches this can take several weeks.
979

    
980
When resubmitting patches, please do not make any significant changes
981
not related to the comments received during review. Such patches will
982
be rejected. Instead, submit  significant changes or new features as
983
separate patches.
984

    
985
@section Regression tests
986

    
987
Before submitting a patch (or committing to the repository), you should at least
988
test that you did not break anything.
989

    
990
The regression tests build a synthetic video stream and a synthetic
991
audio stream. These are then encoded and decoded with all codecs or
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formats. The CRC (or MD5) of each generated file is recorded in a
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result file. A 'diff' is launched to compare the reference results and
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the result file.
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The regression tests then go on to test the FFserver code with a
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limited set of streams. It is important that this step runs correctly
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as well.
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Run 'make test' to test all the codecs and formats.
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Run 'make fulltest' to test all the codecs, formats and FFserver.
1003

    
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[Of course, some patches may change the results of the regression tests. In
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this case, the reference results of the regression tests shall be modified
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accordingly].
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@bye