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diff --git a/contrib/ffmpeg/doc/ffmpeg-doc.texi b/contrib/ffmpeg/doc/ffmpeg-doc.texi new file mode 100644 index 000000000..e4e6430fd --- /dev/null +++ b/contrib/ffmpeg/doc/ffmpeg-doc.texi @@ -0,0 +1,1656 @@ +\input texinfo @c -*- texinfo -*- + +@settitle FFmpeg Documentation +@titlepage +@sp 7 +@center @titlefont{FFmpeg Documentation} +@sp 3 +@end titlepage + + +@chapter Introduction + +FFmpeg is a very fast video and audio converter. It can also grab from +a live audio/video source. + +The command line interface is designed to be intuitive, in the sense +that FFmpeg tries to figure out all parameters that can possibly be +derived automatically. You usually only have to specify the target +bitrate you want. + +FFmpeg can also convert from any sample rate to any other, and resize +video on the fly with a high quality polyphase filter. + +@chapter Quick Start + +@c man begin EXAMPLES +@section Video and Audio grabbing + +FFmpeg can grab video and audio from devices given that you specify the input +format and device. + +@example +ffmpeg -f audio_device -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg +@end example + +Note that you must activate the right video source and channel before +launching FFmpeg with any TV viewer such as xawtv +(@url{http://bytesex.org/xawtv/}) by Gerd Knorr. You also +have to set the audio recording levels correctly with a +standard mixer. + +@section X11 grabbing + +FFmpeg can grab the X11 display. + +@example +ffmpeg -f x11grab -i :0.0 /tmp/out.mpg +@end example + +0.0 is display.screen number of your X11 server, same as +the DISPLAY environment variable. + +@example +ffmpeg -f x11grab -i :0.0+10,20 /tmp/out.mpg +@end example + +0.0 is display.screen number of your X11 server, same as the DISPLAY environment +variable. 10 is the x-offset and 20 the y-offset for the grabbing. + +@section Video and Audio file format conversion + +* FFmpeg can use any supported file format and protocol as input: + +Examples: + +* You can use YUV files as input: + +@example +ffmpeg -i /tmp/test%d.Y /tmp/out.mpg +@end example + +It will use the files: +@example +/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V, +/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc... +@end example + +The Y files use twice the resolution of the U and V files. They are +raw files, without header. They can be generated by all decent video +decoders. You must specify the size of the image with the @option{-s} option +if FFmpeg cannot guess it. + +* You can input from a raw YUV420P file: + +@example +ffmpeg -i /tmp/test.yuv /tmp/out.avi +@end example + +test.yuv is a file containing raw YUV planar data. Each frame is composed +of the Y plane followed by the U and V planes at half vertical and +horizontal resolution. + +* You can output to a raw YUV420P file: + +@example +ffmpeg -i mydivx.avi hugefile.yuv +@end example + +* You can set several input files and output files: + +@example +ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg +@end example + +Converts the audio file a.wav and the raw YUV video file a.yuv +to MPEG file a.mpg. + +* You can also do audio and video conversions at the same time: + +@example +ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2 +@end example + +Converts a.wav to MPEG audio at 22050Hz sample rate. + +* You can encode to several formats at the same time and define a +mapping from input stream to output streams: + +@example +ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0 +@end example + +Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map +file:index' specifies which input stream is used for each output +stream, in the order of the definition of output streams. + +* You can transcode decrypted VOBs + +@example +ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec mp3 -ab 128k snatch.avi +@end example + +This is a typical DVD ripping example; the input is a VOB file, the +output an AVI file with MPEG-4 video and MP3 audio. Note that in this +command we use B-frames so the MPEG-4 stream is DivX5 compatible, and +GOP size is 300 which means one intra frame every 10 seconds for 29.97fps +input video. Furthermore, the audio stream is MP3-encoded so you need +to enable LAME support by passing @code{--enable-mp3lame} to configure. +The mapping is particularly useful for DVD transcoding +to get the desired audio language. + +NOTE: To see the supported input formats, use @code{ffmpeg -formats}. +@c man end + +@chapter Invocation + +@section Syntax + +The generic syntax is: + +@example +@c man begin SYNOPSIS +ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}... +@c man end +@end example +@c man begin DESCRIPTION +As a general rule, options are applied to the next specified +file. Therefore, order is important, and you can have the same +option on the command line multiple times. Each occurrence is +then applied to the next input or output file. + +* To set the video bitrate of the output file to 64kbit/s: +@example +ffmpeg -i input.avi -b 64k output.avi +@end example + +* To force the frame rate of the input and output file to 24 fps: +@example +ffmpeg -r 24 -i input.avi output.avi +@end example + +* To force the frame rate of the output file to 24 fps: +@example +ffmpeg -i input.avi -r 24 output.avi +@end example + +* To force the frame rate of input file to 1 fps and the output file to 24 fps: +@example +ffmpeg -r 1 -i input.avi -r 24 output.avi +@end example + +The format option may be needed for raw input files. + +By default, FFmpeg tries to convert as losslessly as possible: It +uses the same audio and video parameters for the outputs as the one +specified for the inputs. +@c man end + +@c man begin OPTIONS +@section Main options + +@table @option +@item -L +Show license. + +@item -h +Show help. + +@item -version +Show version. + +@item -formats +Show available formats, codecs, protocols, ... + +@item -f fmt +Force format. + +@item -i filename +input filename + +@item -y +Overwrite output files. + +@item -t duration +Set the recording time in seconds. +@code{hh:mm:ss[.xxx]} syntax is also supported. + +@item -fs limit_size +Set the file size limit. + +@item -ss position +Seek to given time position in seconds. +@code{hh:mm:ss[.xxx]} syntax is also supported. + +@item -itsoffset offset +Set the input time offset in seconds. +@code{[-]hh:mm:ss[.xxx]} syntax is also supported. +This option affects all the input files that follow it. +The offset is added to the timestamps of the input files. +Specifying a positive offset means that the corresponding +streams are delayed by 'offset' seconds. + +@item -title string +Set the title. + +@item -timestamp time +Set the timestamp. + +@item -author string +Set the author. + +@item -copyright string +Set the copyright. + +@item -comment string +Set the comment. + +@item -album string +Set the album. + +@item -track number +Set the track. + +@item -year number +Set the year. + +@item -v verbose +Control amount of logging. + +@item -target type +Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd", +"ntsc-svcd", ... ). All the format options (bitrate, codecs, +buffer sizes) are then set automatically. You can just type: + +@example +ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg +@end example + +Nevertheless you can specify additional options as long as you know +they do not conflict with the standard, as in: + +@example +ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg +@end example + +@item -dframes number +Set the number of data frames to record. + +@item -scodec codec +Force subtitle codec ('copy' to copy stream). + +@item -newsubtitle +Add a new subtitle stream to the current output stream. + +@item -slang code +Set the ISO 639 language code (3 letters) of the current subtitle stream. + +@end table + +@section Video Options + +@table @option +@item -b bitrate +Set the video bitrate in bit/s (default = 200 kb/s). +@item -vframes number +Set the number of video frames to record. +@item -r fps +Set frame rate (Hz value, fraction or abbreviation), (default = 25). +@item -s size +Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source). +The following abbreviations are recognized: +@table @samp +@item sqcif +128x96 +@item qcif +176x144 +@item cif +352x288 +@item 4cif +704x576 +@end table + +@item -aspect aspect +Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777). +@item -croptop size +Set top crop band size (in pixels). +@item -cropbottom size +Set bottom crop band size (in pixels). +@item -cropleft size +Set left crop band size (in pixels). +@item -cropright size +Set right crop band size (in pixels). +@item -padtop size +Set top pad band size (in pixels). +@item -padbottom size +Set bottom pad band size (in pixels). +@item -padleft size +Set left pad band size (in pixels). +@item -padright size +Set right pad band size (in pixels). +@item -padcolor (hex color) +Set color of padded bands. The value for padcolor is expressed +as a six digit hexadecimal number where the first two digits +represent red, the middle two digits green and last two digits +blue (default = 000000 (black)). +@item -vn +Disable video recording. +@item -bt tolerance +Set video bitrate tolerance (in bit/s). +@item -maxrate bitrate +Set max video bitrate tolerance (in bit/s). +@item -minrate bitrate +Set min video bitrate tolerance (in bit/s). +@item -bufsize size +Set rate control buffer size (in bits). +@item -vcodec codec +Force video codec to @var{codec}. Use the @code{copy} special value to +tell that the raw codec data must be copied as is. +@item -sameq +Use same video quality as source (implies VBR). + +@item -pass n +Select the pass number (1 or 2). It is useful to do two pass +encoding. The statistics of the video are recorded in the first +pass and the video is generated at the exact requested bitrate +in the second pass. + +@item -passlogfile file +Set two pass logfile name to @var{file}. + +@item -newvideo +Add a new video stream to the current output stream. + +@end table + +@section Advanced Video Options + +@table @option +@item -pix_fmt format +Set pixel format. +@item -g gop_size +Set the group of pictures size. +@item -intra +Use only intra frames. +@item -vdt n +Discard threshold. +@item -qscale q +Use fixed video quantizer scale (VBR). +@item -qmin q +minimum video quantizer scale (VBR) +@item -qmax q +maximum video quantizer scale (VBR) +@item -qdiff q +maximum difference between the quantizer scales (VBR) +@item -qblur blur +video quantizer scale blur (VBR) +@item -qcomp compression +video quantizer scale compression (VBR) + +@item -lmin lambda +minimum video lagrange factor (VBR) +@item -lmax lambda +max video lagrange factor (VBR) +@item -mblmin lambda +minimum macroblock quantizer scale (VBR) +@item -mblmax lambda +maximum macroblock quantizer scale (VBR) + +These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units, +but you may use the QP2LAMBDA constant to easily convert from 'q' units: +@example +ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext +@end example + +@item -rc_init_cplx complexity +initial complexity for single pass encoding +@item -b_qfactor factor +qp factor between P- and B-frames +@item -i_qfactor factor +qp factor between P- and I-frames +@item -b_qoffset offset +qp offset between P- and B-frames +@item -i_qoffset offset +qp offset between P- and I-frames +@item -rc_eq equation +Set rate control equation (@pxref{FFmpeg formula +evaluator}) (default = @code{tex^qComp}). +@item -rc_override override +rate control override for specific intervals +@item -me method +Set motion estimation method to @var{method}. +Available methods are (from lowest to best quality): +@table @samp +@item zero +Try just the (0, 0) vector. +@item phods +@item log +@item x1 +@item epzs +(default method) +@item full +exhaustive search (slow and marginally better than epzs) +@end table + +@item -dct_algo algo +Set DCT algorithm to @var{algo}. Available values are: +@table @samp +@item 0 +FF_DCT_AUTO (default) +@item 1 +FF_DCT_FASTINT +@item 2 +FF_DCT_INT +@item 3 +FF_DCT_MMX +@item 4 +FF_DCT_MLIB +@item 5 +FF_DCT_ALTIVEC +@end table + +@item -idct_algo algo +Set IDCT algorithm to @var{algo}. Available values are: +@table @samp +@item 0 +FF_IDCT_AUTO (default) +@item 1 +FF_IDCT_INT +@item 2 +FF_IDCT_SIMPLE +@item 3 +FF_IDCT_SIMPLEMMX +@item 4 +FF_IDCT_LIBMPEG2MMX +@item 5 +FF_IDCT_PS2 +@item 6 +FF_IDCT_MLIB +@item 7 +FF_IDCT_ARM +@item 8 +FF_IDCT_ALTIVEC +@item 9 +FF_IDCT_SH4 +@item 10 +FF_IDCT_SIMPLEARM +@end table + +@item -er n +Set error resilience to @var{n}. +@table @samp +@item 1 +FF_ER_CAREFUL (default) +@item 2 +FF_ER_COMPLIANT +@item 3 +FF_ER_AGGRESSIVE +@item 4 +FF_ER_VERY_AGGRESSIVE +@end table + +@item -ec bit_mask +Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of +the following values: +@table @samp +@item 1 +FF_EC_GUESS_MVS (default = enabled) +@item 2 +FF_EC_DEBLOCK (default = enabled) +@end table + +@item -bf frames +Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4). +@item -mbd mode +macroblock decision +@table @samp +@item 0 +FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg). +@item 1 +FF_MB_DECISION_BITS: Choose the one which needs the fewest bits. +@item 2 +FF_MB_DECISION_RD: rate distortion +@end table + +@item -4mv +Use four motion vector by macroblock (MPEG-4 only). +@item -part +Use data partitioning (MPEG-4 only). +@item -bug param +Work around encoder bugs that are not auto-detected. +@item -strict strictness +How strictly to follow the standards. +@item -aic +Enable Advanced intra coding (h263+). +@item -umv +Enable Unlimited Motion Vector (h263+) + +@item -deinterlace +Deinterlace pictures. +@item -ilme +Force interlacing support in encoder (MPEG-2 and MPEG-4 only). +Use this option if your input file is interlaced and you want +to keep the interlaced format for minimum losses. +The alternative is to deinterlace the input stream with +@option{-deinterlace}, but deinterlacing introduces losses. +@item -psnr +Calculate PSNR of compressed frames. +@item -vstats +Dump video coding statistics to @file{vstats_HHMMSS.log}. +@item -vhook module +Insert video processing @var{module}. @var{module} contains the module +name and its parameters separated by spaces. +@item -top n +top=1/bottom=0/auto=-1 field first +@item -dc precision +Intra_dc_precision. +@item -vtag fourcc/tag +Force video tag/fourcc. +@item -qphist +Show QP histogram. +@item -vbsf bitstream filter +Bitstream filters available are "dump_extra", "remove_extra", "noise". +@end table + +@section Audio Options + +@table @option +@item -aframes number +Set the number of audio frames to record. +@item -ar freq +Set the audio sampling frequency (default = 44100 Hz). +@item -ab bitrate +Set the audio bitrate in bit/s (default = 64k). +@item -ac channels +Set the number of audio channels (default = 1). +@item -an +Disable audio recording. +@item -acodec codec +Force audio codec to @var{codec}. Use the @code{copy} special value to +specify that the raw codec data must be copied as is. +@item -newaudio +Add a new audio track to the output file. If you want to specify parameters, +do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..). + +Mapping will be done automatically, if the number of output streams is equal to +the number of input streams, else it will pick the first one that matches. You +can override the mapping using @code{-map} as usual. + +Example: +@example +ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio +@end example +@item -alang code +Set the ISO 639 language code (3 letters) of the current audio stream. +@end table + +@section Advanced Audio options: + +@table @option +@item -atag fourcc/tag +Force audio tag/fourcc. +@item -absf bitstream filter +Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp". +@end table + +@section Subtitle options: + +@table @option +@item -scodec codec +Force subtitle codec ('copy' to copy stream). +@item -newsubtitle +Add a new subtitle stream to the current output stream. +@item -slang code +Set the ISO 639 language code (3 letters) of the current subtitle stream. +@end table + +@section Audio/Video grab options + +@table @option +@item -vc channel +Set video grab channel (DV1394 only). +@item -tvstd standard +Set television standard (NTSC, PAL (SECAM)). +@item -isync +Synchronize read on input. +@end table + +@section Advanced options + +@table @option +@item -map input stream id[:input stream id] +Set stream mapping from input streams to output streams. +Just enumerate the input streams in the order you want them in the output. +[input stream id] sets the (input) stream to sync against. +@item -map_meta_data outfile:infile +Set meta data information of outfile from infile. +@item -debug +Print specific debug info. +@item -benchmark +Add timings for benchmarking. +@item -dump +Dump each input packet. +@item -hex +When dumping packets, also dump the payload. +@item -bitexact +Only use bit exact algorithms (for codec testing). +@item -ps size +Set packet size in bits. +@item -re +Read input at native frame rate. Mainly used to simulate a grab device. +@item -loop_input +Loop over the input stream. Currently it works only for image +streams. This option is used for automatic FFserver testing. +@item -loop_output number_of_times +Repeatedly loop output for formats that support looping such as animated GIF +(0 will loop the output infinitely). +@item -threads count +Thread count. +@item -vsync parameter +Video sync method. Video will be stretched/squeezed to match the timestamps, +it is done by duplicating and dropping frames. With -map you can select from +which stream the timestamps should be taken. You can leave either video or +audio unchanged and sync the remaining stream(s) to the unchanged one. +@item -async samples_per_second +Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps, +the parameter is the maximum samples per second by which the audio is changed. +-async 1 is a special case where only the start of the audio stream is corrected +without any later correction. +@end table + +@node FFmpeg formula evaluator +@section FFmpeg formula evaluator + +When evaluating a rate control string, FFmpeg uses an internal formula +evaluator. + +The following binary operators are available: @code{+}, @code{-}, +@code{*}, @code{/}, @code{^}. + +The following unary operators are available: @code{+}, @code{-}, +@code{(...)}. + +The following functions are available: +@table @var +@item sinh(x) +@item cosh(x) +@item tanh(x) +@item sin(x) +@item cos(x) +@item tan(x) +@item exp(x) +@item log(x) +@item squish(x) +@item gauss(x) +@item abs(x) +@item max(x, y) +@item min(x, y) +@item gt(x, y) +@item lt(x, y) +@item eq(x, y) +@item bits2qp(bits) +@item qp2bits(qp) +@end table + +The following constants are available: +@table @var +@item PI +@item E +@item iTex +@item pTex +@item tex +@item mv +@item fCode +@item iCount +@item mcVar +@item var +@item isI +@item isP +@item isB +@item avgQP +@item qComp +@item avgIITex +@item avgPITex +@item avgPPTex +@item avgBPTex +@item avgTex +@end table + +@c man end + +@ignore + +@setfilename ffmpeg +@settitle FFmpeg video converter + +@c man begin SEEALSO +ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}. +@c man end + +@c man begin AUTHOR +Fabrice Bellard +@c man end + +@end ignore + +@section Protocols + +The filename can be @file{-} to read from standard input or to write +to standard output. + +FFmpeg also handles many protocols specified with an URL syntax. + +Use 'ffmpeg -formats' to see a list of the supported protocols. + +The protocol @code{http:} is currently used only to communicate with +FFserver (see the FFserver documentation). When FFmpeg will be a +video player it will also be used for streaming :-) + +@chapter Tips + +@itemize +@item For streaming at very low bitrate application, use a low frame rate +and a small GOP size. This is especially true for RealVideo where +the Linux player does not seem to be very fast, so it can miss +frames. An example is: + +@example +ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm +@end example + +@item The parameter 'q' which is displayed while encoding is the current +quantizer. The value 1 indicates that a very good quality could +be achieved. The value 31 indicates the worst quality. If q=31 appears +too often, it means that the encoder cannot compress enough to meet +your bitrate. You must either increase the bitrate, decrease the +frame rate or decrease the frame size. + +@item If your computer is not fast enough, you can speed up the +compression at the expense of the compression ratio. You can use +'-me zero' to speed up motion estimation, and '-intra' to disable +motion estimation completely (you have only I-frames, which means it +is about as good as JPEG compression). + +@item To have very low audio bitrates, reduce the sampling frequency +(down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3). + +@item To have a constant quality (but a variable bitrate), use the option +'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst +quality). + +@item When converting video files, you can use the '-sameq' option which +uses the same quality factor in the encoder as in the decoder. +It allows almost lossless encoding. + +@end itemize + + +@chapter external libraries + +FFmpeg can be hooked up with a number of external libraries to add support +for more formats. + +@section AMR + +AMR comes in two different flavors, WB and NB. FFmpeg can make use of the +AMR WB (floating-point mode) and the AMR NB (both floating-point and +fixed-point mode) reference decoders and encoders. + +@itemize + +@item For AMR WB floating-point download TS26.204 V5.1.0 from +@url{http://www.3gpp.org/ftp/Specs/archive/26_series/26.204/26204-510.zip} +and extract the source to @file{libavcodec/amrwb_float/}. + +@item For AMR NB floating-point download TS26.104 REL-5 V5.1.0 from +@url{http://www.3gpp.org/ftp/Specs/archive/26_series/26.104/26104-510.zip} +and extract the source to @file{libavcodec/amr_float/}. +If you try this on Alpha, you may need to change @code{Word32} to +@code{int} in @file{amr/typedef.h}. + +@item For AMR NB fixed-point download TS26.073 REL-5 V5.1.0 from +@url{http://www.3gpp.org/ftp/Specs/archive/26_series/26.073/26073-510.zip} +and extract the source to @file{libavcodec/amr}. +You must also add @code{-DMMS_IO} and remove @code{-pedantic-errors} +to/from @code{CFLAGS} in @file{libavcodec/amr/makefile}, i.e. +``@code{CFLAGS = -Wall -I. \$(CFLAGS_\$(MODE)) -D\$(VAD) -DMMS_IO}''. + +@end itemize + + +@chapter Supported File Formats and Codecs + +You can use the @code{-formats} option to have an exhaustive list. + +@section File Formats + +FFmpeg supports the following file formats through the @code{libavformat} +library: + +@multitable @columnfractions .4 .1 .1 .4 +@item Supported File Format @tab Encoding @tab Decoding @tab Comments +@item MPEG audio @tab X @tab X +@item MPEG-1 systems @tab X @tab X +@tab muxed audio and video +@item MPEG-2 PS @tab X @tab X +@tab also known as @code{VOB} file +@item MPEG-2 TS @tab @tab X +@tab also known as DVB Transport Stream +@item ASF@tab X @tab X +@item AVI@tab X @tab X +@item WAV@tab X @tab X +@item Macromedia Flash@tab X @tab X +@tab Only embedded audio is decoded. +@item FLV @tab X @tab X +@tab Macromedia Flash video files +@item Real Audio and Video @tab X @tab X +@item Raw AC3 @tab X @tab X +@item Raw MJPEG @tab X @tab X +@item Raw MPEG video @tab X @tab X +@item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X +@item Raw CRI ADX audio @tab X @tab X +@item Raw Shorten audio @tab @tab X +@item SUN AU format @tab X @tab X +@item NUT @tab X @tab X @tab NUT Open Container Format +@item QuickTime @tab X @tab X +@item MPEG-4 @tab X @tab X +@tab MPEG-4 is a variant of QuickTime. +@item Raw MPEG4 video @tab X @tab X +@item DV @tab X @tab X +@item 4xm @tab @tab X +@tab 4X Technologies format, used in some games. +@item Playstation STR @tab @tab X +@item Id RoQ @tab @tab X +@tab Used in Quake III, Jedi Knight 2, other computer games. +@item Interplay MVE @tab @tab X +@tab Format used in various Interplay computer games. +@item WC3 Movie @tab @tab X +@tab Multimedia format used in Origin's Wing Commander III computer game. +@item Sega FILM/CPK @tab @tab X +@tab Used in many Sega Saturn console games. +@item Westwood Studios VQA/AUD @tab @tab X +@tab Multimedia formats used in Westwood Studios games. +@item Id Cinematic (.cin) @tab @tab X +@tab Used in Quake II. +@item FLIC format @tab @tab X +@tab .fli/.flc files +@item Sierra VMD @tab @tab X +@tab Used in Sierra CD-ROM games. +@item Sierra Online @tab @tab X +@tab .sol files used in Sierra Online games. +@item Matroska @tab @tab X +@item Electronic Arts Multimedia @tab @tab X +@tab Used in various EA games; files have extensions like WVE and UV2. +@item Nullsoft Video (NSV) format @tab @tab X +@item ADTS AAC audio @tab X @tab X +@item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro. +@item American Laser Games MM @tab @tab X +@tab Multimedia format used in games like Mad Dog McCree +@item AVS @tab @tab X +@tab Multimedia format used by the Creature Shock game. +@item Smacker @tab @tab X +@tab Multimedia format used by many games. +@item GXF @tab X @tab X +@tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers. +@item CIN @tab @tab X +@tab Multimedia format used by Delphine Software games. +@item MXF @tab @tab X +@tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry. +@item SEQ @tab @tab X +@tab Tiertex .seq files used in the DOS CDROM version of the game Flashback. +@item DXA @tab @tab X +@tab This format is used in non-Windows version of Feeble Files game and +different game cutscenes repacked for use with ScummVM. +@item THP @tab @tab X +@tab Used on the Nintendo GameCube (video only) +@end multitable + +@code{X} means that encoding (resp. decoding) is supported. + +@section Image Formats + +FFmpeg can read and write images for each frame of a video sequence. The +following image formats are supported: + +@multitable @columnfractions .4 .1 .1 .4 +@item Supported Image Format @tab Encoding @tab Decoding @tab Comments +@item PGM, PPM @tab X @tab X +@item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support. +@item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0 +@item JPEG @tab X @tab X @tab Progressive JPEG is not supported. +@item .Y.U.V @tab X @tab X @tab one raw file per component +@item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated. +@item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet. +@item Targa @tab @tab X @tab Targa (.TGA) image format. +@item TIFF @tab @tab X @tab Only 24 bit/pixel images are supported. +@item SGI @tab X @tab X @tab SGI RGB image format +@end multitable + +@code{X} means that encoding (resp. decoding) is supported. + +@section Video Codecs + +@multitable @columnfractions .4 .1 .1 .4 +@item Supported Codec @tab Encoding @tab Decoding @tab Comments +@item MPEG-1 video @tab X @tab X +@item MPEG-2 video @tab X @tab X +@item MPEG-4 @tab X @tab X +@item MSMPEG4 V1 @tab X @tab X +@item MSMPEG4 V2 @tab X @tab X +@item MSMPEG4 V3 @tab X @tab X +@item WMV7 @tab X @tab X +@item WMV8 @tab X @tab X @tab not completely working +@item WMV9 @tab @tab X @tab not completely working +@item VC1 @tab @tab X +@item H.261 @tab X @tab X +@item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0 +@item H.264 @tab @tab X +@item RealVideo 1.0 @tab X @tab X +@item RealVideo 2.0 @tab X @tab X +@item MJPEG @tab X @tab X +@item lossless MJPEG @tab X @tab X +@item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported +@item Apple MJPEG-B @tab @tab X +@item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X +@item DV @tab X @tab X +@item HuffYUV @tab X @tab X +@item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1) +@item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW) +@item Asus v1 @tab X @tab X @tab fourcc: ASV1 +@item Asus v2 @tab X @tab X @tab fourcc: ASV2 +@item Creative YUV @tab @tab X @tab fourcc: CYUV +@item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1 +@item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3 +@item On2 VP3 @tab @tab X @tab still experimental +@item On2 VP5 @tab @tab X @tab fourcc: VP50 +@item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62 +@item Theora @tab X @tab X @tab still experimental +@item Intel Indeo 3 @tab @tab X +@item FLV @tab X @tab X @tab Sorenson H.263 used in Flash +@item Flash Screen Video @tab X @tab X @tab fourcc: FSV1 +@item ATI VCR1 @tab @tab X @tab fourcc: VCR1 +@item ATI VCR2 @tab @tab X @tab fourcc: VCR2 +@item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR +@item 4X Video @tab @tab X @tab Used in certain computer games. +@item Sony Playstation MDEC @tab @tab X +@item Id RoQ @tab @tab X @tab Used in Quake III, Jedi Knight 2, other computer games. +@item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files. +@item Interplay Video @tab @tab X @tab Used in Interplay .MVE files. +@item Apple Animation @tab @tab X @tab fourcc: 'rle ' +@item Apple Graphics @tab @tab X @tab fourcc: 'smc ' +@item Apple Video @tab @tab X @tab fourcc: rpza +@item Apple QuickDraw @tab @tab X @tab fourcc: qdrw +@item Cinepak @tab @tab X +@item Microsoft RLE @tab @tab X +@item Microsoft Video-1 @tab @tab X +@item Westwood VQA @tab @tab X +@item Id Cinematic Video @tab @tab X @tab Used in Quake II. +@item Planar RGB @tab @tab X @tab fourcc: 8BPS +@item FLIC video @tab @tab X +@item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK +@item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20 +@item VMD Video @tab @tab X @tab Used in Sierra VMD files. +@item MSZH @tab @tab X @tab Part of LCL +@item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental +@item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC +@item IBM Ultimotion @tab @tab X @tab fourcc: ULTI +@item Miro VideoXL @tab @tab X @tab fourcc: VIXL +@item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1 +@item LOCO @tab @tab X @tab +@item Winnov WNV1 @tab @tab X @tab +@item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC +@item Fraps FPS1 @tab @tab X @tab +@item CamStudio @tab @tab X @tab fourcc: CSCD +@item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree +@item ZMBV @tab X @tab X @tab Encoder works only on PAL8 +@item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game. +@item Smacker Video @tab @tab X @tab Video encoding used in Smacker. +@item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files. +@item KMVC @tab @tab X @tab Codec used in Worms games. +@item VMware Video @tab @tab X @tab Codec used in videos captured by VMware. +@item Cin Video @tab @tab X @tab Codec used in Delphine Software games. +@item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game. +@item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game. +@item AVID DNxHD @tab @tab X @tab aka SMPTE VC3 +@end multitable + +@code{X} means that encoding (resp. decoding) is supported. + +@section Audio Codecs + +@multitable @columnfractions .4 .1 .1 .1 .7 +@item Supported Codec @tab Encoding @tab Decoding @tab Comments +@item MPEG audio layer 2 @tab IX @tab IX +@item MPEG audio layer 1/3 @tab IX @tab IX +@tab MP3 encoding is supported through the external library LAME. +@item AC3 @tab IX @tab IX +@tab liba52 is used internally for decoding. +@item Vorbis @tab X @tab X +@item WMA V1/V2 @tab X @tab X +@item AAC @tab X @tab X +@tab Supported through the external library libfaac/libfaad. +@item Microsoft ADPCM @tab X @tab X +@item MS IMA ADPCM @tab X @tab X +@item QT IMA ADPCM @tab @tab X +@item 4X IMA ADPCM @tab @tab X +@item G.726 ADPCM @tab X @tab X +@item Duck DK3 IMA ADPCM @tab @tab X +@tab Used in some Sega Saturn console games. +@item Duck DK4 IMA ADPCM @tab @tab X +@tab Used in some Sega Saturn console games. +@item Westwood Studios IMA ADPCM @tab @tab X +@tab Used in Westwood Studios games like Command and Conquer. +@item SMJPEG IMA ADPCM @tab @tab X +@tab Used in certain Loki game ports. +@item CD-ROM XA ADPCM @tab @tab X +@item CRI ADX ADPCM @tab X @tab X +@tab Used in Sega Dreamcast games. +@item Electronic Arts ADPCM @tab @tab X +@tab Used in various EA titles. +@item Creative ADPCM @tab @tab X +@tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2 +@item RA144 @tab @tab X +@tab Real 14400 bit/s codec +@item RA288 @tab @tab X +@tab Real 28800 bit/s codec +@item RADnet @tab X @tab IX +@tab Real low bitrate AC3 codec, liba52 is used for decoding. +@item AMR-NB @tab X @tab X +@tab Supported through an external library. +@item AMR-WB @tab X @tab X +@tab Supported through an external library. +@item DV audio @tab @tab X +@item Id RoQ DPCM @tab @tab X +@tab Used in Quake III, Jedi Knight 2, other computer games. +@item Interplay MVE DPCM @tab @tab X +@tab Used in various Interplay computer games. +@item Xan DPCM @tab @tab X +@tab Used in Origin's Wing Commander IV AVI files. +@item Sierra Online DPCM @tab @tab X +@tab Used in Sierra Online game audio files. +@item Apple MACE 3 @tab @tab X +@item Apple MACE 6 @tab @tab X +@item FLAC lossless audio @tab @tab X +@item Shorten lossless audio @tab @tab X +@item Apple lossless audio @tab @tab X +@tab QuickTime fourcc 'alac' +@item FFmpeg Sonic @tab X @tab X +@tab experimental lossy/lossless codec +@item Qdesign QDM2 @tab @tab X +@tab there are still some distortions +@item Real COOK @tab @tab X +@tab All versions except 5.1 are supported +@item DSP Group TrueSpeech @tab @tab X +@item True Audio (TTA) @tab @tab X +@item Smacker Audio @tab @tab X +@item WavPack Audio @tab @tab X +@item Cin Audio @tab @tab X +@tab Codec used in Delphine Software games. +@item Intel Music Coder @tab @tab X +@item Musepack @tab @tab X +@tab Only SV7 is supported +@item DT$ Coherent Audio @tab @tab X +@end multitable + +@code{X} means that encoding (resp. decoding) is supported. + +@code{I} means that an integer-only version is available, too (ensures high +performance on systems without hardware floating point support). + +@chapter Platform Specific information + +@section BSD + +BSD make will not build FFmpeg, you need to install and use GNU Make +(@file{gmake}). + +@section Windows + +To get help and instructions for using FFmpeg under Windows, check out +the FFmpeg Windows Help Forum at +@url{http://arrozcru.no-ip.org/ffmpeg/}. + +@subsection Native Windows compilation + +@itemize +@item Install the current versions of MSYS and MinGW from +@url{http://www.mingw.org/}. You can find detailed installation +instructions in the download section and the FAQ. + +NOTE: Use at least bash 3.1. Older versions are known to be failing on the +configure script. + +@item If you want to test the FFplay, also download +the MinGW development library of SDL 1.2.x +(@file{SDL-devel-1.2.x-mingw32.tar.gz}) from +@url{http://www.libsdl.org}. Unpack it in a temporary directory, and +unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool +directory. Edit the @file{sdl-config} script so that it gives the +correct SDL directory when invoked. + +@item Extract the current version of FFmpeg. + +@item Start the MSYS shell (file @file{msys.bat}). + +@item Change to the FFmpeg directory and follow + the instructions of how to compile FFmpeg (file +@file{INSTALL}). Usually, launching @file{./configure} and @file{make} +suffices. If you have problems using SDL, verify that +@file{sdl-config} can be launched from the MSYS command line. + +@item You can install FFmpeg in @file{Program Files/FFmpeg} by typing +@file{make install}. Do not forget to copy @file{SDL.dll} to the place +you launch @file{ffplay} from. + +@end itemize + +Notes: +@itemize + +@item The target @file{make wininstaller} can be used to create a +Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll} +must be copied to the FFmpeg directory in order to build the +installer. + +@item By using @code{./configure --enable-shared} when configuring FFmpeg, +you can build @file{avcodec.dll} and @file{avformat.dll}. With +@code{make install} you install the FFmpeg DLLs and the associated +headers in @file{Program Files/FFmpeg}. + +@item Visual C++ compatibility: If you used @code{./configure --enable-shared} +when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual +C++ @code{lib} tool to build @code{avcodec.lib} and +@code{avformat.lib}. With these libraries you can link your Visual C++ +code directly with the FFmpeg DLLs (see below). + +@end itemize + +@subsection Visual C++ compatibility + +FFmpeg will not compile under Visual C++ -- and it has too many +dependencies on the GCC compiler to make a port viable. However, +if you want to use the FFmpeg libraries in your own applications, +you can still compile those applications using Visual C++. An +important restriction to this is that you have to use the +dynamically linked versions of the FFmpeg libraries (i.e. the +DLLs), and you have to make sure that Visual-C++-compatible +import libraries are created during the FFmpeg build process. + +This description of how to use the FFmpeg libraries with Visual C++ is +based on Visual C++ 2005 Express Edition Beta 2. If you have a different +version, you might have to modify the procedures slightly. + +Here are the step-by-step instructions for building the FFmpeg libraries +so they can be used with Visual C++: + +@enumerate + +@item Install Visual C++ (if you have not done so already). + +@item Install MinGW and MSYS as described above. + +@item Add a call to @file{vcvars32.bat} (which sets up the environment +variables for the Visual C++ tools) as the first line of +@file{msys.bat}. The standard location for @file{vcvars32.bat} is +@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat}, +and the standard location for @file{msys.bat} is +@file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the +following line as the first line of @file{msys.bat}: + +@code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"} + +@item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}. +If you get a help message with the command line options of @code{link.exe}, +this means your environment variables are set up correctly, the +Microsoft linker is on the path and will be used by FFmpeg to +create Visual-C++-compatible import libraries. + +@item Extract the current version of FFmpeg and change to the FFmpeg directory. + +@item Type the command +@code{./configure --enable-shared --disable-static --enable-memalign-hack} +to configure and, if that did not produce any errors, +type @code{make} to build FFmpeg. + +@item The subdirectories @file{libavformat}, @file{libavcodec}, and +@file{libavutil} should now contain the files @file{avformat.dll}, +@file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib}, +@file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three +DLLs to your System32 directory (typically @file{C:\Windows\System32}). + +@end enumerate + +And here is how to use these libraries with Visual C++: + +@enumerate + +@item Create a new console application ("File / New / Project") and then +select "Win32 Console Application". On the appropriate page of the +Application Wizard, uncheck the "Precompiled headers" option. + +@item Write the source code for your application, or, for testing, just +copy the code from an existing sample application into the source file +that Visual C++ has already created for you. (Note that your source +filehas to have a @code{.cpp} extension; otherwise, Visual C++ will not +compile the FFmpeg headers correctly because in C mode, it does not +recognize the @code{inline} keyword.) For example, you can copy +@file{output_example.c} from the FFmpeg distribution (but you will +have to make minor modifications so the code will compile under +C++, see below). + +@item Open the "Project / Properties" dialog box. In the "Configuration" +combo box, select "All Configurations" so that the changes you make will +affect both debug and release builds. In the tree view on the left hand +side, select "C/C++ / General", then edit the "Additional Include +Directories" setting to contain the complete paths to the +@file{libavformat}, @file{libavcodec}, and @file{libavutil} +subdirectories of your FFmpeg directory. Note that the directories have +to be separated using semicolons. Now select "Linker / General" from the +tree view and edit the "Additional Library Directories" setting to +contain the same three directories. + +@item Still in the "Project / Properties" dialog box, select "Linker / Input" +from the tree view, then add the files @file{avformat.lib}, +@file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional +Dependencies". Note that the names of the libraries have to be separated +using spaces. + +@item Now, select "C/C++ / Code Generation" from the tree view. Select +"Debug" in the "Configuration" combo box. Make sure that "Runtime +Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in +the "Configuration" combo box and make sure that "Runtime Library" is +set to "Multi-threaded DLL". + +@item Click "OK" to close the "Project / Properties" dialog box and build +the application. Hopefully, it should compile and run cleanly. If you +used @file{output_example.c} as your sample application, you will get a +few compiler errors, but they are easy to fix. The first type of error +occurs because Visual C++ does not allow an @code{int} to be converted to +an @code{enum} without a cast. To solve the problem, insert the required +casts (this error occurs once for a @code{CodecID} and once for a +@code{CodecType}). The second type of error occurs because C++ requires +the return value of @code{malloc} to be cast to the exact type of the +pointer it is being assigned to. Visual C++ will complain that, for +example, @code{(void *)} is being assigned to @code{(uint8_t *)} without +an explicit cast. So insert an explicit cast in these places to silence +the compiler. The third type of error occurs because the @code{snprintf} +library function is called @code{_snprintf} under Visual C++. So just +add an underscore to fix the problem. With these changes, +@file{output_example.c} should compile under Visual C++, and the +resulting executable should produce valid video files. + +@end enumerate + +@subsection Cross compilation for Windows with Linux + +You must use the MinGW cross compilation tools available at +@url{http://www.mingw.org/}. + +Then configure FFmpeg with the following options: +@example +./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc- +@end example +(you can change the cross-prefix according to the prefix chosen for the +MinGW tools). + +Then you can easily test FFmpeg with Wine +(@url{http://www.winehq.com/}). + +@subsection Compilation under Cygwin + +Cygwin works very much like Unix. + +Just install your Cygwin with all the "Base" packages, plus the +following "Devel" ones: +@example +binutils, gcc-core, make, subversion +@end example + +Do not install binutils-20060709-1 (they are buggy on shared builds); +use binutils-20050610-1 instead. + +Then run + +@example +./configure --enable-static --disable-shared +@end example + +to make a static build or + +@example +./configure --enable-shared --disable-static +@end example + +to build shared libraries. + +If you want to build FFmpeg with additional libraries, download Cygwin +"Devel" packages for Ogg and Vorbis from any Cygwin packages repository +and/or SDL, xvid, faac, faad2 packages from Cygwin Ports, +(@url{http://cygwinports.dotsrc.org/}). + +@subsection Crosscompilation for Windows under Cygwin + +With Cygwin you can create Windows binaries that do not need the cygwin1.dll. + +Just install your Cygwin as explained before, plus these additional +"Devel" packages: +@example +gcc-mingw-core, mingw-runtime, mingw-zlib +@end example + +and add some special flags to your configure invocation. + +For a static build run +@example +./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin +@end example + +and for a build with shared libraries +@example +./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin +@end example + +@section BeOS + +The configure script should guess the configuration itself. +Networking support is currently not finished. +errno issues fixed by Andrew Bachmann. + +Old stuff: + +François Revol - revol at free dot fr - April 2002 + +The configure script should guess the configuration itself, +however I still did not test building on the net_server version of BeOS. + +FFserver is broken (needs poll() implementation). + +There are still issues with errno codes, which are negative in BeOS, and +that FFmpeg negates when returning. This ends up turning errors into +valid results, then crashes. +(To be fixed) + +@chapter Developers Guide + +@section API +@itemize @bullet +@item libavcodec is the library containing the codecs (both encoding and +decoding). Look at @file{libavcodec/apiexample.c} to see how to use it. + +@item libavformat is the library containing the file format handling (mux and +demux code for several formats). Look at @file{ffplay.c} to use it in a +player. See @file{output_example.c} to use it to generate audio or video +streams. + +@end itemize + +@section Integrating libavcodec or libavformat in your program + +You can integrate all the source code of the libraries to link them +statically to avoid any version problem. All you need is to provide a +'config.mak' and a 'config.h' in the parent directory. See the defines +generated by ./configure to understand what is needed. + +You can use libavcodec or libavformat in your commercial program, but +@emph{any patch you make must be published}. The best way to proceed is +to send your patches to the FFmpeg mailing list. + +@node Coding Rules +@section Coding Rules + +FFmpeg is programmed in the ISO C90 language with a few additional +features from ISO C99, namely: +@itemize @bullet +@item +the @samp{inline} keyword; +@item +@samp{//} comments; +@item +designated struct initializers (@samp{struct s x = @{ .i = 17 @};}) +@item +compound literals (@samp{x = (struct s) @{ 17, 23 @};}) +@end itemize + +These features are supported by all compilers we care about, so we will not +accept patches to remove their use unless they absolutely do not impair +clarity and performance. + +All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also +compiles with several other compilers, such as the Compaq ccc compiler +or Sun Studio 9, and we would like to keep it that way unless it would +be exceedingly involved. To ensure compatibility, please do not use any +additional C99 features or GCC extensions. Especially watch out for: +@itemize @bullet +@item +mixing statements and declarations; +@item +@samp{long long} (use @samp{int64_t} instead); +@item +@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar; +@item +GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}). +@end itemize + +Indent size is 4. +The presentation is the one specified by 'indent -i4 -kr -nut'. +The TAB character is forbidden outside of Makefiles as is any +form of trailing whitespace. Commits containing either will be +rejected by the Subversion repository. + +Main priority in FFmpeg is simplicity and small code size (=less +bugs). + +Comments: Use the JavaDoc/Doxygen +format (see examples below) so that code documentation +can be generated automatically. All nontrivial functions should have a comment +above them explaining what the function does, even if it is just one sentence. +All structures and their member variables should be documented, too. +@example +/** + * @@file mpeg.c + * MPEG codec. + * @@author ... + */ + +/** + * Summary sentence. + * more text ... + * ... + */ +typedef struct Foobar@{ + int var1; /**< var1 description */ + int var2; ///< var2 description + /** var3 description */ + int var3; +@} Foobar; + +/** + * Summary sentence. + * more text ... + * ... + * @@param my_parameter description of my_parameter + * @@return return value description + */ +int myfunc(int my_parameter) +... +@end example + +fprintf and printf are forbidden in libavformat and libavcodec, +please use av_log() instead. + +@section Development Policy + +@enumerate +@item + You must not commit code which breaks FFmpeg! (Meaning unfinished but + enabled code which breaks compilation or compiles but does not work or + breaks the regression tests) + You can commit unfinished stuff (for testing etc), but it must be disabled + (#ifdef etc) by default so it does not interfere with other developers' + work. +@item + You do not have to over-test things. If it works for you, and you think it + should work for others, then commit. If your code has problems + (portability, triggers compiler bugs, unusual environment etc) they will be + reported and eventually fixed. +@item + Do not commit unrelated changes together, split them into self-contained + pieces. Also do not forget that if part B depends on part A, but A does not + depend on B, then A can and should be committed first and separate from B. + Keeping changes well split into self-contained parts makes reviewing and + understanding them on the commit log mailing list easier. This also helps + in case of debugging later on. + Also if you have doubts about splitting or not splitting, do not hesitate to + ask/disscuss it on the developer mailing list. +@item + Do not change behavior of the program (renaming options etc) without + first discussing it on the ffmpeg-devel mailing list. Do not remove + functionality from the code. Just improve! + + Note: Redundant code can be removed. +@item + Do not commit changes to the build system (Makefiles, configure script) + which change behavior, defaults etc, without asking first. The same + applies to compiler warning fixes, trivial looking fixes and to code + maintained by other developers. We usually have a reason for doing things + the way we do. Send your changes as patches to the ffmpeg-devel mailing + list, and if the code maintainers say OK, you may commit. This does not + apply to files you wrote and/or maintain. +@item + We refuse source indentation and other cosmetic changes if they are mixed + with functional changes, such commits will be rejected and removed. Every + developer has his own indentation style, you should not change it. Of course + if you (re)write something, you can use your own style, even though we would + prefer if the indentation throughout FFmpeg was consistent (Many projects + force a given indentation style - we do not.). If you really need to make + indentation changes (try to avoid this), separate them strictly from real + changes. + + NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code, + then either do NOT change the indentation of the inner part within (do not + move it to the right)! or do so in a separate commit +@item + Always fill out the commit log message. Describe in a few lines what you + changed and why. You can refer to mailing list postings if you fix a + particular bug. Comments such as "fixed!" or "Changed it." are unacceptable. +@item + If you apply a patch by someone else, include the name and email address in + the log message. Since the ffmpeg-cvslog mailing list is publicly + archived you should add some SPAM protection to the email address. Send an + answer to ffmpeg-devel (or wherever you got the patch from) saying that + you applied the patch. +@item + Do NOT commit to code actively maintained by others without permission. + Send a patch to ffmpeg-devel instead. If noone answers within a reasonable + timeframe (12h for build failures and security fixes, 3 days small changes, + 1 week for big patches) then commit your patch if you think it is OK. + Also note, the maintainer can simply ask for more time to review! +@item + Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits + are sent there and reviewed by all the other developers. Bugs and possible + improvements or general questions regarding commits are discussed there. We + expect you to react if problems with your code are uncovered. +@item + Update the documentation if you change behavior or add features. If you are + unsure how best to do this, send a patch to ffmpeg-devel, the documentation + maintainer(s) will review and commit your stuff. +@item + Try to keep important discussions and requests (also) on the public + developer mailing list, so that all developers can benefit from them. +@item + Never write to unallocated memory, never write over the end of arrays, + always check values read from some untrusted source before using them + as array index or other risky things. +@item + Remember to check if you need to bump versions for the specific libav + parts (libavutil, libavcodec, libavformat) you are changing. You need + to change the version integer and the version string. + Incrementing the first component means no backward compatibility to + previous versions (e.g. removal of a function from the public API). + Incrementing the second component means backward compatible change + (e.g. addition of a function to the public API). + Incrementing the third component means a noteworthy binary compatible + change (e.g. encoder bug fix that matters for the decoder). +@item + If you add a new codec, remember to update the changelog, add it to + the supported codecs table in the documentation and bump the second + component of the @file{libavcodec} version number appropriately. If + it has a fourcc, add it to @file{libavformat/avienc.c}, even if it + is only a decoder. +@item + Do not change code to hide warnings without ensuring that the underlying + logic is correct and thus the warning was inappropriate. +@end enumerate + +We think our rules are not too hard. If you have comments, contact us. + +Note, these rules are mostly borrowed from the MPlayer project. + +@section Submitting patches + +First, (@pxref{Coding Rules}) above if you did not yet. + +When you submit your patch, try to send a unified diff (diff '-up' +option). I cannot read other diffs :-) + +Also please do not submit patches which contain several unrelated changes. +Split them into individual self-contained patches; this makes reviewing +them much easier. + +Run the regression tests before submitting a patch so that you can +verify that there are no big problems. + +Patches should be posted as base64 encoded attachments (or any other +encoding which ensures that the patch will not be trashed during +transmission) to the ffmpeg-devel mailing list, see +@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel} + +It also helps quite a bit if you tell us what the patch does (for example +'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant +and has no lrint()') + +@section Patch review process + +All patches posted to ffmpeg-devel will be reviewed, unless they contain a +clear note that the patch is not for SVN. +Reviews and comments will be posted as replies to the patch on the +mailing list. The patch submitter then has to take care of every comment, +that can be by resubmitting a changed patch or by disscussion. Resubmitted +patches will themselves be reviewed like any other patch. If at some point +a patch passes review with no comments then it is approved, that can for +simple and small patches happen immediately while large patches will generally +have to be changed and reviewed many times before they are approved. +After a patch is approved it will be committed to the repository. + +We will review all submitted patches, but sometimes we are quite busy so +especially for large patches this can take several weeks. + +When resubmitting patches, please do not make any significant changes +not related to the comments received during review. Such patches will +be rejected. Instead, submit significant changes or new features as +separate patches. + +@section Regression tests + +Before submitting a patch (or committing to the repository), you should at least +test that you did not break anything. + +The regression tests build a synthetic video stream and a synthetic +audio stream. These are then encoded and decoded with all codecs or +formats. The CRC (or MD5) of each generated file is recorded in a +result file. A 'diff' is launched to compare the reference results and +the result file. + +The regression tests then go on to test the FFserver code with a +limited set of streams. It is important that this step runs correctly +as well. + +Run 'make test' to test all the codecs and formats. + +Run 'make fulltest' to test all the codecs, formats and FFserver. + +[Of course, some patches may change the results of the regression tests. In +this case, the reference results of the regression tests shall be modified +accordingly]. + +@bye |