1 \input texinfo @c -*- texinfo -*-
3 @settitle FFmpeg Documentation
6 @center @titlefont{FFmpeg Documentation}
13 FFmpeg is a very fast video and audio converter. It can also grab from
14 a live audio/video source.
16 The command line interface is designed to be intuitive, in the sense
17 that ffmpeg tries to figure out all the parameters, when
18 possible. You have usually to give only the target bitrate you want.
20 FFmpeg can also convert from any sample rate to any other, and resize
21 video on the fly with a high quality polyphase filter.
26 @section Video and Audio grabbing
28 FFmpeg can use a video4linux compatible video source and any Open Sound
35 Note that you must activate the right video source and channel before
36 launching ffmpeg. You can use any TV viewer such as xawtv
37 (@url{http://bytesex.org/xawtv/}) by Gerd Knorr which I find very
38 good. You must also set correctly the audio recording levels with a
41 @section Video and Audio file format conversion
43 * ffmpeg can use any supported file format and protocol as input:
47 * You can input from YUV files:
50 ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
53 It will use the files:
55 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
56 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
59 The Y files use twice the resolution of the U and V files. They are
60 raw files, without header. They can be generated by all decent video
61 decoders. You must specify the size of the image with the @option{-s} option
62 if ffmpeg cannot guess it.
64 * You can input from a RAW YUV420P file:
67 ffmpeg -i /tmp/test.yuv /tmp/out.avi
70 The RAW YUV420P is a file containing RAW YUV planar, for each frame first
71 come the Y plane followed by U and V planes, which are half vertical and
72 horizontal resolution.
74 * You can output to a RAW YUV420P file:
77 ffmpeg -i mydivx.avi -o hugefile.yuv
80 * You can set several input files and output files:
83 ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
86 Convert the audio file a.wav and the raw yuv video file a.yuv
89 * You can also do audio and video conversions at the same time:
92 ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
95 Convert the sample rate of a.wav to 22050 Hz and encode it to MPEG audio.
97 * You can encode to several formats at the same time and define a
98 mapping from input stream to output streams:
101 ffmpeg -i /tmp/a.wav -ab 64 /tmp/a.mp2 -ab 128 /tmp/b.mp2 -map 0:0 -map 0:0
104 Convert a.wav to a.mp2 at 64 kbits and b.mp2 at 128 kbits. '-map
105 file:index' specify which input stream is used for each output
106 stream, in the order of the definition of output streams.
108 * You can transcode decrypted VOBs
111 ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800 -g 300 -bf 2 -acodec mp3 -ab 128 snatch.avi
114 This is a typical DVD ripper example, input from a VOB file, output
115 to an AVI file with MPEG-4 video and MP3 audio, note that in this
116 command we use B frames so the MPEG-4 stream is DivX5 compatible, GOP
117 size is 300 that means an INTRA frame every 10 seconds for 29.97 fps
118 input video. Also the audio stream is MP3 encoded so you need LAME
119 support which is enabled using @code{--enable-mp3lame} when
120 configuring. The mapping is particularly useful for DVD transcoding
121 to get the desired audio language.
123 NOTE: to see the supported input formats, use @code{ffmpeg -formats}.
130 The generic syntax is:
133 @c man begin SYNOPSIS
134 ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
137 @c man begin DESCRIPTION
138 If no input file is given, audio/video grabbing is done.
140 As a general rule, options are applied to the next specified
141 file. For example, if you give the @option{-b 64} option, it sets the video
142 bitrate of the next file. Format option may be needed for raw input
145 By default, ffmpeg tries to convert as losslessly as possible: it
146 uses the same audio and video parameter for the outputs as the one
147 specified for the inputs.
151 @section Main options
161 show available formats, codecs, protocols, ...
170 overwrite output files
173 set the recording time in seconds. @code{hh:mm:ss[.xxx]} syntax is also
177 seek to given time position. @code{hh:mm:ss[.xxx]} syntax is also
186 @item -copyright string
189 @item -comment string
193 specify target file type ("vcd", "svcd", "dvd", "pal-vcd", "ntsc-svcd", ... ). All the format
194 options (bitrate, codecs, buffer sizes) are automatically set by this
195 option. You can just type:
198 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
201 Nevertheless you can specify additional options as long as you know they do not compromise the
205 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
209 activate high quality settings
211 @item -itsoffset offset
212 set the input time offset in seconds. @code{[-]hh:mm:ss[.xxx]} syntax
213 is also supported. This option affects all the input files that
214 follow it. The offset is added to the input files' timestamps;
215 specifying a positive offset means that the corresponding streams are
216 delayed by 'offset' seconds.
220 @section Video Options
224 set the video bitrate in kbit/s (default = 200 kb/s)
226 set frame rate (default = 25)
228 set frame size. The format is @samp{WxH} (default 160x128). The
229 following abbreviations are recognized:
242 set aspect ratio (4:3, 16:9 or 1.3333, 1.7777)
244 set top crop band size (in pixels)
245 @item -cropbottom size
246 set bottom crop band size (in pixels)
248 set left crop band size (in pixels)
249 @item -cropright size
250 set right crop band size (in pixels)
252 set top pad band size (in pixels)
253 @item -padbottom size
254 set bottom pad band size (in pixels)
256 set left pad band size (in pixels)
258 set right pad band size (in pixels)
259 @item -padcolor (hex color)
260 set color of padded bands. The value for pad color is expressed
261 as a six digit hexidecimal number where the first two digits represent red,
262 middle two digits green and last two digits blue. Defaults to 000000 (black)
264 disable video recording
266 set video bitrate tolerance (in kbit/s)
267 @item -maxrate bitrate
268 set max video bitrate tolerance (in kbit/s)
269 @item -minrate bitrate
270 set min video bitrate tolerance (in kbit/s)
272 set ratecontrol buffere size (in kbit)
274 force video codec to @var{codec}. Use the @code{copy} special value to
275 tell that the raw codec data must be copied as is.
277 use same video quality as source (implies VBR)
280 select the pass number (1 or 2). It is useful to do two pass
281 encoding. The statistics of the video are recorded in the first pass and
282 the video at the exact requested bit rate is generated in the second
285 @item -passlogfile file
286 select two pass log file name to @var{file}.
290 @section Advanced Video Options
294 set the group of picture size
296 use only intra frames
298 use fixed video quantiser scale (VBR)
300 min video quantiser scale (VBR)
302 max video quantiser scale (VBR)
304 max difference between the quantiser scale (VBR)
306 video quantiser scale blur (VBR)
307 @item -qcomp compression
308 video quantiser scale compression (VBR)
310 @item -rc_init_cplx complexity
311 initial complexity for 1-pass encoding
312 @item -b_qfactor factor
313 qp factor between p and b frames
314 @item -i_qfactor factor
315 qp factor between p and i frames
316 @item -b_qoffset offset
317 qp offset between p and b frames
318 @item -i_qoffset offset
319 qp offset between p and i frames
320 @item -rc_eq equation
321 set rate control equation (@pxref{FFmpeg formula
322 evaluator}). Default is @code{tex^qComp}.
323 @item -rc_override override
324 rate control override for specific intervals
326 set motion estimation method to @var{method}. Available methods are
327 (from lower to best quality):
330 Try just the (0, 0) vector.
337 exhaustive search (slow and marginally better than epzs)
341 set dct algorithm to @var{algo}. Available values are:
344 FF_DCT_AUTO (default)
357 @item -idct_algo algo
358 set idct algorithm to @var{algo}. Available values are:
361 FF_IDCT_AUTO (default)
385 set error resilience to @var{n}.
388 FF_ER_CAREFULL (default)
394 FF_ER_VERY_AGGRESSIVE
398 set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
399 the following values:
402 FF_EC_GUESS_MVS (default=enabled)
404 FF_EC_DEBLOCK (default=enabled)
408 use 'frames' B frames (supported for MPEG-1, MPEG-2 and MPEG-4)
413 FF_MB_DECISION_SIMPLE: use mb_cmp (cannot change it yet in ffmpeg)
415 FF_MB_DECISION_BITS: chooses the one which needs the fewest bits
417 FF_MB_DECISION_RD: rate distoration
421 use four motion vector by macroblock (only MPEG-4)
423 use data partitioning (only MPEG-4)
425 workaround not auto detected encoder bugs
426 @item -strict strictness
427 how strictly to follow the standarts
429 enable Advanced intra coding (h263+)
431 enable Unlimited Motion Vector (h263+)
436 force interlacing support in encoder (only MPEG-2 and MPEG-4). Use this option
437 if your input file is interlaced and if you want to keep the interlaced
438 format for minimum losses. The alternative is to deinterlace the input
439 stream with @option{-deinterlace}, but deinterlacing introduces more
442 calculate PSNR of compressed frames
444 dump video coding statistics to @file{vstats_HHMMSS.log}.
446 insert video processing @var{module}. @var{module} contains the module
447 name and its parameters separated by spaces.
450 @section Audio Options
454 set the audio sampling freq (default = 44100 Hz)
456 set the audio bitrate in kbit/s (default = 64)
458 set the number of audio channels (default = 1)
460 disable audio recording
462 force audio codec to @var{codec}. Use the @code{copy} special value to
463 tell that the raw codec data must be copied as is.
466 @section Audio/Video grab options
470 set video grab device (e.g. @file{/dev/video0})
472 set video grab channel (DV1394 only)
473 @item -tvstd standard
474 set television standard (NTSC, PAL (SECAM))
478 set audio device (e.g. @file{/dev/dsp})
481 @section Advanced options
484 @item -map file:stream
485 set input stream mapping
487 print specific debug info
489 add timings for benchmarking
491 dump each input packet
493 only use bit exact algorithms (for codec testing)
495 set packet size in bits
497 read input at native frame rate. Mainly used to simulate a grab device.
499 loop over the input stream. Currently it works only for image
500 streams. This option is used for ffserver automatic testing.
503 @node FFmpeg formula evaluator
504 @section FFmpeg formula evaluator
506 When evaluating a rate control string, FFmpeg uses an internal formula
509 The following binary operators are available: @code{+}, @code{-},
510 @code{*}, @code{/}, @code{^}.
512 The following unary operators are available: @code{+}, @code{-},
515 The following functions are available:
537 The following constants are available:
566 @settitle FFmpeg video converter
569 ffserver(1), ffplay(1) and the html documentation of @file{ffmpeg}.
580 The filename can be @file{-} to read from the standard input or to write
581 to the standard output.
583 ffmpeg handles also many protocols specified with the URL syntax.
585 Use 'ffmpeg -formats' to have a list of the supported protocols.
587 The protocol @code{http:} is currently used only to communicate with
588 ffserver (see the ffserver documentation). When ffmpeg will be a
589 video player it will also be used for streaming :-)
594 @item For streaming at very low bit rate application, use a low frame rate
595 and a small gop size. This is especially true for real video where
596 the Linux player does not seem to be very fast, so it can miss
597 frames. An example is:
600 ffmpeg -g 3 -r 3 -t 10 -b 50 -s qcif -f rv10 /tmp/b.rm
603 @item The parameter 'q' which is displayed while encoding is the current
604 quantizer. The value of 1 indicates that a very good quality could
605 be achieved. The value of 31 indicates the worst quality. If q=31
606 too often, it means that the encoder cannot compress enough to meet
607 your bit rate. You must either increase the bit rate, decrease the
608 frame rate or decrease the frame size.
610 @item If your computer is not fast enough, you can speed up the
611 compression at the expense of the compression ratio. You can use
612 '-me zero' to speed up motion estimation, and '-intra' to disable
613 completely motion estimation (you have only I frames, which means it
614 is about as good as JPEG compression).
616 @item To have very low bitrates in audio, reduce the sampling frequency
617 (down to 22050 kHz for mpeg audio, 22050 or 11025 for ac3).
619 @item To have a constant quality (but a variable bitrate), use the option
620 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
623 @item When converting video files, you can use the '-sameq' option which
624 uses in the encoder the same quality factor than in the decoder. It
625 allows to be almost lossless in encoding.
629 @chapter Supported File Formats and Codecs
631 You can use the @code{-formats} option to have an exhaustive list.
633 @section File Formats
635 FFmpeg supports the following file formats through the @code{libavformat}
638 @multitable @columnfractions .4 .1 .1
639 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
640 @item MPEG audio @tab X @tab X
641 @item MPEG1 systems @tab X @tab X
642 @tab muxed audio and video
643 @item MPEG2 PS @tab X @tab X
644 @tab also known as @code{VOB} file
645 @item MPEG2 TS @tab @tab X
646 @tab also known as DVB Transport Stream
647 @item ASF@tab X @tab X
648 @item AVI@tab X @tab X
649 @item WAV@tab X @tab X
650 @item Macromedia Flash@tab X @tab X
651 @tab Only embedded audio is decoded
652 @item FLV @tab X @tab X
653 @tab Macromedia Flash video files
654 @item Real Audio and Video @tab X @tab X
655 @item Raw AC3 @tab X @tab X
656 @item Raw MJPEG @tab X @tab X
657 @item Raw MPEG video @tab X @tab X
658 @item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
659 @item Raw CRI ADX audio @tab X @tab X
660 @item SUN AU format @tab X @tab X
661 @item NUT @tab X @tab X @tab NUT Open Container Format
662 @item Quicktime @tab X @tab X
663 @item MPEG4 @tab X @tab X
664 @tab MPEG4 is a variant of Quicktime
665 @item Raw MPEG4 video @tab X @tab X
666 @item DV @tab X @tab X
667 @item 4xm @tab @tab X
668 @tab 4X Technologies format, used in some games
669 @item Playstation STR @tab @tab X
670 @item Id RoQ @tab @tab X
671 @tab used in Quake III, Jedi Knight 2, other computer games
672 @item Interplay MVE @tab @tab X
673 @tab format used in various Interplay computer games
674 @item WC3 Movie @tab @tab X
675 @tab multimedia format used in Origin's Wing Commander III computer game
676 @item Sega FILM/CPK @tab @tab X
677 @tab used in many Sega Saturn console games
678 @item Westwood Studios VQA/AUD @tab @tab X
679 @tab Multimedia formats used in Westwood Studios games
680 @item Id Cinematic (.cin) @tab @tab X
681 @tab Used in Quake II
682 @item FLIC format @tab @tab X
684 @item Sierra VMD @tab @tab X
685 @tab used in Sierra CD-ROM games
686 @item Sierra Online @tab @tab X
687 @tab .sol files used in Sierra Online games
688 @item Matroska @tab @tab X
690 @item Electronic Arts Multimedia @tab @tab X
691 @tab used in various EA games; files have extensions like WVE and UV2
693 @code{X} means that the encoding (resp. decoding) is supported.
695 @section Image Formats
697 FFmpeg can read and write images for each frame of a video sequence. The
698 following image formats are supported:
700 @multitable @columnfractions .4 .1 .1
701 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
702 @item PGM, PPM @tab X @tab X
703 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support
704 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
705 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported
706 @item .Y.U.V @tab X @tab X @tab One raw file per component
707 @item Animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated
708 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet
709 @item SGI @tab X @tab X @tab SGI RGB image format
712 @code{X} means that the encoding (resp. decoding) is supported.
714 @section Video Codecs
716 @multitable @columnfractions .4 .1 .1 .7
717 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
718 @item MPEG1 video @tab X @tab X
719 @item MPEG2 video @tab X @tab X
720 @item MPEG4 @tab X @tab X @tab Also known as DIVX4/5
721 @item MSMPEG4 V1 @tab X @tab X
722 @item MSMPEG4 V2 @tab X @tab X
723 @item MSMPEG4 V3 @tab X @tab X @tab Also known as DIVX3
724 @item WMV7 @tab X @tab X
725 @item WMV8 @tab X @tab X @tab Not completely working
726 @item H263(+) @tab X @tab X @tab Also known as Real Video 1.0
727 @item MJPEG @tab X @tab X
728 @item Lossless MJPEG @tab X @tab X
729 @item Apple MJPEG-B @tab @tab X
730 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
731 @item DV @tab X @tab X
732 @item Huff YUV @tab X @tab X
733 @item FFmpeg Video 1 @tab X @tab X @tab Experimental lossless codec (fourcc: FFV1)
734 @item FFmpeg Snow @tab X @tab X @tab Experimental wavelet codec (fourcc: SNOW)
735 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
736 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
737 @item Creative YUV @tab @tab X @tab fourcc: CYUV
738 @item H.264 @tab @tab X
739 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
740 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
741 @item On2 VP3 @tab @tab X @tab still experimental
742 @item Theora @tab @tab X @tab still experimental
743 @item Intel Indeo 3 @tab @tab X @tab only works on i386 right now
744 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
745 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
746 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
747 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
748 @item 4X Video @tab @tab X @tab used in certain computer games
749 @item Sony Playstation MDEC @tab @tab X
750 @item Id RoQ @tab @tab X @tab used in Quake III, Jedi Knight 2, other computer games
751 @item Xan/WC3 @tab @tab X @tab used in Wing Commander III .MVE files
752 @item Interplay Video @tab @tab X @tab used in Interplay .MVE files
753 @item Apple Animation @tab @tab X @tab fourcc: 'rle '
754 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
755 @item Apple Video @tab @tab X @tab fourcc: rpza
756 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
757 @item Cinepak @tab @tab X
758 @item Microsoft RLE @tab @tab X
759 @item Microsoft Video-1 @tab @tab X
760 @item Westwood VQA @tab @tab X
761 @item Id Cinematic Video @tab @tab X @tab used in Quake II
762 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
763 @item FLIC video @tab @tab X
764 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
765 @item VMD Video @tab @tab X @tab used in Sierra VMD files
766 @item MSZH @tab @tab X @tab Part of LCL
767 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
768 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
769 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
772 @code{X} means that the encoding (resp. decoding) is supported.
774 Check at @url{http://www.mplayerhq.hu/~michael/codec-features.html} to
775 get a precise comparison of FFmpeg MPEG4 codec compared to the other
778 @section Audio Codecs
780 @multitable @columnfractions .4 .1 .1 .1 .7
781 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
782 @item MPEG audio layer 2 @tab IX @tab IX
783 @item MPEG audio layer 1/3 @tab IX @tab IX
784 @tab MP3 encoding is supported through the external library LAME
785 @item AC3 @tab IX @tab IX
786 @tab liba52 is used internally for decoding
787 @item Vorbis @tab X @tab X
788 @tab supported through the external library libvorbis
789 @item WMA V1/V2 @tab @tab X
790 @item AAC @tab X @tab X
791 @tab supported through the external library libfaac/libfaad
792 @item Microsoft ADPCM @tab X @tab X
793 @item MS IMA ADPCM @tab X @tab X
794 @item QT IMA ADPCM @tab @tab X
795 @item 4X IMA ADPCM @tab @tab X
796 @item G.726 ADPCM @tab X @tab X
797 @item Duck DK3 IMA ADPCM @tab @tab X
798 @tab used in some Sega Saturn console games
799 @item Duck DK4 IMA ADPCM @tab @tab X
800 @tab used in some Sega Saturn console games
801 @item Westwood Studios IMA ADPCM @tab @tab X
802 @tab used in Westwood Studios games like Command and Conquer
803 @item SMJPEG IMA ADPCM @tab @tab X
804 @tab used in certain Loki game ports
805 @item CD-ROM XA ADPCM @tab @tab X
806 @item CRI ADX ADPCM @tab X @tab X
807 @tab used in Sega Dreamcast games
808 @item Electronic Arts ADPCM @tab @tab X
809 @tab used in various EA titles
810 @item Creative ADPCM @tab @tab X
811 @item RA144 @tab @tab X
812 @tab Real 14400 bit/s codec
813 @item RA288 @tab @tab X
814 @tab Real 28800 bit/s codec
815 @item RADnet @tab X @tab IX
816 @tab Real lowbitrate AC3 codec, liba52 is used for decoding
817 @item AMR-NB @tab X @tab X
818 @tab supported through an external library
819 @item AMR-WB @tab X @tab X
820 @tab supported through an external library
821 @item DV audio @tab @tab X
822 @item Id RoQ DPCM @tab @tab X
823 @tab used in Quake III, Jedi Knight 2, other computer games
824 @item Interplay MVE DPCM @tab @tab X
825 @tab used in various Interplay computer games
826 @item Xan DPCM @tab @tab X
827 @tab used in Origin's Wing Commander IV AVI files
828 @item Sierra Online DPCM @tab @tab X
829 @tab used in Sierra Online game audio files
830 @item Apple MACE 3 @tab @tab X
831 @item Apple MACE 6 @tab @tab X
832 @item FLAC @tab @tab X
833 @item FFmpeg Sonic @tab X @tab X
834 @tab Experimental lossy/lossless codec
837 @code{X} means that the encoding (resp. decoding) is supported.
839 @code{I} means that an integer only version is available too (ensures highest
840 performances on systems without hardware floating point support).
842 @chapter Platform Specific information
846 ffmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
847 preferred compiler now for ffmpeg. All future optimizations will depend on
848 features only found in GCC 3.2.
854 @subsection Native Windows compilation
857 @item Install the current versions of MSYS and MinGW from
858 @url{http://www.mingw.org/}. You can find detailed installation
859 instructions in the download section and the FAQ.
861 @item If you want to test the FFmpeg Simple Media Player, also download
862 the MinGW development library of SDL 1.2.x
863 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
864 @url{http://www.libsdl.org}. Unpack it in a temporary place, and
865 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
866 directory. Edit the @file{sdl-config} script so that it gives the
867 correct SDL directory when invoked.
869 @item Extract the current version of FFmpeg (the latest release version or the current CVS snapshot whichever is recommended).
871 @item Start the MSYS shell (file @file{msys.bat}).
873 @item Change to the FFMPEG directory and follow
874 the instructions of how to compile ffmpeg (file
875 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
876 suffices. If you have problems using SDL, verify that
877 @file{sdl-config} can be launched from the MSYS command line.
879 @item You can install FFmpeg in @file{Program Files/FFmpeg} by typing @file{make install}. Don't forget to copy @file{SDL.dll} at the place you launch
887 @item The target @file{make wininstaller} can be used to create a
888 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
889 must be copied in the ffmpeg directory in order to build the
892 @item By using @code{./configure --enable-shared} when configuring ffmpeg,
893 you can build @file{avcodec.dll} and @file{avformat.dll}. With
894 @code{make install} you install the FFmpeg DLLs and the associated
895 headers in @file{Program Files/FFmpeg}.
897 @item Visual C++ compatibility: if you used @code{./configure --enable-shared}
898 when configuring FFmpeg, then FFmpeg tries to use the Microsoft Visual
899 C++ @code{lib} tool to build @code{avcodec.lib} and
900 @code{avformat.lib}. With these libraries, you can link your Visual C++
901 code directly with the FFmpeg DLLs.
905 @subsection Cross compilation for Windows with Linux
907 You must use the MinGW cross compilation tools available at
908 @url{http://www.mingw.org/}.
910 Then configure ffmpeg with the following options:
912 ./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
914 (you can change the cross-prefix according to the prefix choosen for the
917 Then you can easily test ffmpeg with wine
918 (@url{http://www.winehq.com/}).
924 The configure script should guess the configuration itself.
925 Networking support is currently not finished.
926 errno issues fixed by Andrew Bachmann.
930 François Revol - revol at free dot fr - April 2002
932 The configure script should guess the configuration itself,
933 however I still didn't tested building on net_server version of BeOS.
935 ffserver is broken (needs poll() implementation).
937 There is still issues with errno codes, which are negative in BeOs, and
938 that ffmpeg negates when returning. This ends up turning errors into
939 valid results, then crashes.
942 @chapter Developers Guide
946 @item libavcodec is the library containing the codecs (both encoding and
947 decoding). See @file{libavcodec/apiexample.c} to see how to use it.
949 @item libavformat is the library containing the file formats handling (mux and
950 demux code for several formats). See @file{ffplay.c} to use it in a
951 player. See @file{output_example.c} to use it to generate audio or video
956 @section Integrating libavcodec or libavformat in your program
958 You can integrate all the source code of the libraries to link them
959 statically to avoid any version problem. All you need is to provide a
960 'config.mak' and a 'config.h' in the parent directory. See the defines
961 generated by ./configure to understand what is needed.
963 You can use libavcodec or libavformat in your commercial program, but
964 @emph{any patch you make must be published}. The best way to proceed is
965 to send your patches to the ffmpeg mailing list.
968 @section Coding Rules
970 ffmpeg is programmed in the ISO C90 language with a few additional
971 features from ISO C99, namely:
974 the @samp{inline} keyword;
978 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
980 compound literals (@samp{x = (struct s) { 17, 23 @};})
983 These features are supported by all compilers we care about, so we won't
984 accept patches to remove their use unless they absolutely don't impair
985 clarity and performance.
987 All code must compile with gcc 2.95 and gcc 3.3. Currently, ffmpeg also
988 compiles with several other compilers, such as the Compaq ccc compiler
989 or Sun Studio 9, and we would like to keep it that way unless it would
990 be exceedingly involved. To ensure compatibility, please don't use any
991 additional C99 features or gcc extensions. Watch out especially for:
994 mixing statements and declarations;
996 @samp{long long} (use @samp{int64_t} instead);
998 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1000 gcc statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1003 Indent size is 4. The TAB character should not be used.
1004 The presentation is the one specified by 'indent -i4 -kr'.
1006 Main priority in ffmpeg is simplicity and small code size (=less
1009 Comments: use the JavaDoc/Doxygen
1010 format (see examples below) so that a documentation
1011 can be generated automatically. All non trivial functions should have a comment
1012 above it explaining what the function does, even if its just one sentance.
1013 All Structures and their member variables should be documented too.
1026 typedef struct Foobar{
1027 int var1; /**< var1 description */
1028 int var2; ///< var2 description
1029 /** var3 description */
1037 * @param my_parameter description of my_parameter
1038 * @return return value description
1040 int myfunc(int my_parameter)
1044 fprintf and printf are forbidden in libavformat and libavcodec,
1045 please use av_log() instead.
1047 @section Submitting patches
1049 First, (@pxref{Coding Rules}) above if you didn't yet.
1051 When you submit your patch, try to send a unified diff (diff '-up'
1052 option). I cannot read other diffs :-)
1054 Run the regression tests before submitting a patch so that you can
1055 verify that there are no big problems.
1057 Patches should be posted as base64 encoded attachments (or any other
1058 encoding which ensures that the patch wont be trashed during
1059 transmission) to the ffmpeg-devel mailinglist, see
1060 @url{http://lists.sourceforge.net/lists/listinfo/ffmpeg-devel}
1062 It also helps quite a bit if you tell us what the patch does (for example
1063 'replaces lrint by lrintf') , and why (for example '*bsd isnt c99 compliant
1064 and has no lrint()')
1066 We reply to all patches submitted and either apply or reject with some
1067 explanation why, but sometimes we are quite busy so it can take a week or 2
1069 @section Regression tests
1071 Before submitting a patch (or committing with CVS), you should at least
1072 test that you did not break anything.
1074 The regression test build a synthetic video stream and a synthetic
1075 audio stream. Then these are encoded then decoded with all codecs or
1076 formats. The CRC (or MD5) of each generated file is recorded in a
1077 result file. Then a 'diff' is launched with the reference results and
1080 The regression test then goes on to test the ffserver code with a
1081 limited set of streams. It is important that this step runs correctly
1084 Run 'make test' to test all the codecs and formats.
1086 Run 'make fulltest' to test all the codecs, formats and ffserver.
1088 [Of course, some patches may change the regression tests results. In
1089 this case, the regression tests reference results shall be modified