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" or "dvd"). 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
202 activate high quality settings
204 @item -itsoffset offset
205 set the input time offset in seconds. @code{[-]hh:mm:ss[.xxx]} syntax
206 is also supported. This option affects all the input files that
207 follow it. The offset is added to the input files' timestamps;
208 specifying a positive offset means that the corresponding streams are
209 delayed by 'offset' seconds.
213 @section Video Options
217 set the video bitrate in kbit/s (default = 200 kb/s)
219 set frame rate (default = 25)
221 set frame size. The format is @samp{WxH} (default 160x128). The
222 following abbreviations are recognized:
235 set aspect ratio (4:3, 16:9 or 1.3333, 1.7777)
237 set top crop band size (in pixels)
238 @item -cropbottom size
239 set bottom crop band size (in pixels)
241 set left crop band size (in pixels)
242 @item -cropright size
243 set right crop band size (in pixels)
245 set top pad band size (in pixels)
246 @item -padbottom size
247 set bottom pad band size (in pixels)
249 set left pad band size (in pixels)
251 set right pad band size (in pixels)
252 @item -padcolor (hex color)
253 set color of padded bands. The value for pad color is expressed
254 as a six digit hexidecimal number where the first two digits represent red,
255 middle two digits green and last two digits blue. Defaults to 000000 (black)
257 disable video recording
259 set video bitrate tolerance (in kbit/s)
260 @item -maxrate bitrate
261 set max video bitrate tolerance (in kbit/s)
262 @item -minrate bitrate
263 set min video bitrate tolerance (in kbit/s)
265 set ratecontrol buffere size (in kbit)
267 force video codec to @var{codec}. Use the @code{copy} special value to
268 tell that the raw codec data must be copied as is.
270 use same video quality as source (implies VBR)
273 select the pass number (1 or 2). It is useful to do two pass
274 encoding. The statistics of the video are recorded in the first pass and
275 the video at the exact requested bit rate is generated in the second
278 @item -passlogfile file
279 select two pass log file name to @var{file}.
283 @section Advanced Video Options
287 set the group of picture size
289 use only intra frames
291 use fixed video quantiser scale (VBR)
293 min video quantiser scale (VBR)
295 max video quantiser scale (VBR)
297 max difference between the quantiser scale (VBR)
299 video quantiser scale blur (VBR)
300 @item -qcomp compression
301 video quantiser scale compression (VBR)
303 @item -rc_init_cplx complexity
304 initial complexity for 1-pass encoding
305 @item -b_qfactor factor
306 qp factor between p and b frames
307 @item -i_qfactor factor
308 qp factor between p and i frames
309 @item -b_qoffset offset
310 qp offset between p and b frames
311 @item -i_qoffset offset
312 qp offset between p and i frames
313 @item -rc_eq equation
314 set rate control equation (@pxref{FFmpeg formula
315 evaluator}). Default is @code{tex^qComp}.
316 @item -rc_override override
317 rate control override for specific intervals
319 set motion estimation method to @var{method}. Available methods are
320 (from lower to best quality):
323 Try just the (0, 0) vector.
330 exhaustive search (slow and marginally better than epzs)
334 set dct algorithm to @var{algo}. Available values are:
337 FF_DCT_AUTO (default)
350 @item -idct_algo algo
351 set idct algorithm to @var{algo}. Available values are:
354 FF_IDCT_AUTO (default)
378 set error resilience to @var{n}.
381 FF_ER_CAREFULL (default)
387 FF_ER_VERY_AGGRESSIVE
391 set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
392 the following values:
395 FF_EC_GUESS_MVS (default=enabled)
397 FF_EC_DEBLOCK (default=enabled)
401 use 'frames' B frames (supported for MPEG-1, MPEG-2 and MPEG-4)
406 FF_MB_DECISION_SIMPLE: use mb_cmp (cannot change it yet in ffmpeg)
408 FF_MB_DECISION_BITS: chooses the one which needs the fewest bits
410 FF_MB_DECISION_RD: rate distoration
414 use four motion vector by macroblock (only MPEG-4)
416 use data partitioning (only MPEG-4)
418 workaround not auto detected encoder bugs
419 @item -strict strictness
420 how strictly to follow the standarts
422 enable Advanced intra coding (h263+)
424 enable Unlimited Motion Vector (h263+)
429 force interlacing support in encoder (only MPEG-2 and MPEG-4). Use this option
430 if your input file is interlaced and if you want to keep the interlaced
431 format for minimum losses. The alternative is to deinterlace the input
432 stream with @option{-deinterlace}, but deinterlacing introduces more
435 calculate PSNR of compressed frames
437 dump video coding statistics to @file{vstats_HHMMSS.log}.
439 insert video processing @var{module}. @var{module} contains the module
440 name and its parameters separated by spaces.
443 @section Audio Options
447 set the audio sampling freq (default = 44100 Hz)
449 set the audio bitrate in kbit/s (default = 64)
451 set the number of audio channels (default = 1)
453 disable audio recording
455 force audio codec to @var{codec}. Use the @code{copy} special value to
456 tell that the raw codec data must be copied as is.
459 @section Audio/Video grab options
463 set video grab device (e.g. @file{/dev/video0})
465 set video grab channel (DV1394 only)
466 @item -tvstd standard
467 set television standard (NTSC, PAL (SECAM))
471 set audio device (e.g. @file{/dev/dsp})
474 @section Advanced options
477 @item -map file:stream
478 set input stream mapping
480 print specific debug info
482 add timings for benchmarking
484 dump each input packet
486 only use bit exact algorithms (for codec testing)
488 set packet size in bits
490 read input at native frame rate. Mainly used to simulate a grab device.
492 loop over the input stream. Currently it works only for image
493 streams. This option is used for ffserver automatic testing.
496 @node FFmpeg formula evaluator
497 @section FFmpeg formula evaluator
499 When evaluating a rate control string, FFmpeg uses an internal formula
502 The following binary operators are available: @code{+}, @code{-},
503 @code{*}, @code{/}, @code{^}.
505 The following unary operators are available: @code{+}, @code{-},
508 The following functions are available:
530 The following constants are available:
559 @settitle FFmpeg video converter
562 ffserver(1), ffplay(1) and the html documentation of @file{ffmpeg}.
573 The filename can be @file{-} to read from the standard input or to write
574 to the standard output.
576 ffmpeg handles also many protocols specified with the URL syntax.
578 Use 'ffmpeg -formats' to have a list of the supported protocols.
580 The protocol @code{http:} is currently used only to communicate with
581 ffserver (see the ffserver documentation). When ffmpeg will be a
582 video player it will also be used for streaming :-)
587 @item For streaming at very low bit rate application, use a low frame rate
588 and a small gop size. This is especially true for real video where
589 the Linux player does not seem to be very fast, so it can miss
590 frames. An example is:
593 ffmpeg -g 3 -r 3 -t 10 -b 50 -s qcif -f rv10 /tmp/b.rm
596 @item The parameter 'q' which is displayed while encoding is the current
597 quantizer. The value of 1 indicates that a very good quality could
598 be achieved. The value of 31 indicates the worst quality. If q=31
599 too often, it means that the encoder cannot compress enough to meet
600 your bit rate. You must either increase the bit rate, decrease the
601 frame rate or decrease the frame size.
603 @item If your computer is not fast enough, you can speed up the
604 compression at the expense of the compression ratio. You can use
605 '-me zero' to speed up motion estimation, and '-intra' to disable
606 completely motion estimation (you have only I frames, which means it
607 is about as good as JPEG compression).
609 @item To have very low bitrates in audio, reduce the sampling frequency
610 (down to 22050 kHz for mpeg audio, 22050 or 11025 for ac3).
612 @item To have a constant quality (but a variable bitrate), use the option
613 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
616 @item When converting video files, you can use the '-sameq' option which
617 uses in the encoder the same quality factor than in the decoder. It
618 allows to be almost lossless in encoding.
622 @chapter Supported File Formats and Codecs
624 You can use the @code{-formats} option to have an exhaustive list.
626 @section File Formats
628 FFmpeg supports the following file formats through the @code{libavformat}
631 @multitable @columnfractions .4 .1 .1
632 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
633 @item MPEG audio @tab X @tab X
634 @item MPEG1 systems @tab X @tab X
635 @tab muxed audio and video
636 @item MPEG2 PS @tab X @tab X
637 @tab also known as @code{VOB} file
638 @item MPEG2 TS @tab @tab X
639 @tab also known as DVB Transport Stream
640 @item ASF@tab X @tab X
641 @item AVI@tab X @tab X
642 @item WAV@tab X @tab X
643 @item Macromedia Flash@tab X @tab X
644 @tab Only embedded audio is decoded
645 @item FLV @tab X @tab X
646 @tab Macromedia Flash video files
647 @item Real Audio and Video @tab X @tab X
648 @item Raw AC3 @tab X @tab X
649 @item Raw MJPEG @tab X @tab X
650 @item Raw MPEG video @tab X @tab X
651 @item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
652 @item Raw CRI ADX audio @tab X @tab X
653 @item SUN AU format @tab X @tab X
654 @item NUT @tab X @tab X @tab NUT Open Container Format
655 @item Quicktime @tab X @tab X
656 @item MPEG4 @tab X @tab X
657 @tab MPEG4 is a variant of Quicktime
658 @item Raw MPEG4 video @tab X @tab X
659 @item DV @tab X @tab X
660 @item 4xm @tab @tab X
661 @tab 4X Technologies format, used in some games
662 @item Playstation STR @tab @tab X
663 @item Id RoQ @tab @tab X
664 @tab used in Quake III, Jedi Knight 2, other computer games
665 @item Interplay MVE @tab @tab X
666 @tab format used in various Interplay computer games
667 @item WC3 Movie @tab @tab X
668 @tab multimedia format used in Origin's Wing Commander III computer game
669 @item Sega FILM/CPK @tab @tab X
670 @tab used in many Sega Saturn console games
671 @item Westwood Studios VQA/AUD @tab @tab X
672 @tab Multimedia formats used in Westwood Studios games
673 @item Id Cinematic (.cin) @tab @tab X
674 @tab Used in Quake II
675 @item FLIC format @tab @tab X
677 @item Sierra VMD @tab @tab X
678 @tab used in Sierra CD-ROM games
679 @item Sierra Online @tab @tab X
680 @tab .sol files used in Sierra Online games
681 @item Matroska @tab @tab X
684 @code{X} means that the encoding (resp. decoding) is supported.
686 @section Image Formats
688 FFmpeg can read and write images for each frame of a video sequence. The
689 following image formats are supported:
691 @multitable @columnfractions .4 .1 .1
692 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
693 @item PGM, PPM @tab X @tab X
694 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support
695 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
696 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported
697 @item .Y.U.V @tab X @tab X @tab One raw file per component
698 @item Animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated
699 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet
700 @item SGI @tab X @tab X @tab SGI RGB image format
703 @code{X} means that the encoding (resp. decoding) is supported.
705 @section Video Codecs
707 @multitable @columnfractions .4 .1 .1 .7
708 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
709 @item MPEG1 video @tab X @tab X
710 @item MPEG2 video @tab X @tab X
711 @item MPEG4 @tab X @tab X @tab Also known as DIVX4/5
712 @item MSMPEG4 V1 @tab X @tab X
713 @item MSMPEG4 V2 @tab X @tab X
714 @item MSMPEG4 V3 @tab X @tab X @tab Also known as DIVX3
715 @item WMV7 @tab X @tab X
716 @item WMV8 @tab X @tab X @tab Not completely working
717 @item H263(+) @tab X @tab X @tab Also known as Real Video 1.0
718 @item MJPEG @tab X @tab X
719 @item Lossless MJPEG @tab X @tab X
720 @item Apple MJPEG-B @tab @tab X
721 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
722 @item DV @tab X @tab X
723 @item Huff YUV @tab X @tab X
724 @item FFmpeg Video 1 @tab X @tab X @tab Experimental lossless codec (fourcc: FFV1)
725 @item FFmpeg Snow @tab X @tab X @tab Experimental wavelet codec (fourcc: SNOW)
726 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
727 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
728 @item Creative YUV @tab @tab X @tab fourcc: CYUV
729 @item H.264 @tab @tab X
730 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
731 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
732 @item On2 VP3 @tab @tab X @tab still experimental
733 @item Theora @tab @tab X @tab still experimental
734 @item Intel Indeo 3 @tab @tab X @tab only works on i386 right now
735 @item FLV @tab X @tab X @tab Flash H263 variant
736 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
737 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
738 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
739 @item 4X Video @tab @tab X @tab used in certain computer games
740 @item Sony Playstation MDEC @tab @tab X
741 @item Id RoQ @tab @tab X @tab used in Quake III, Jedi Knight 2, other computer games
742 @item Xan/WC3 @tab @tab X @tab used in Wing Commander III .MVE files
743 @item Interplay Video @tab @tab X @tab used in Interplay .MVE files
744 @item Apple Animation @tab @tab X @tab fourcc: 'rle '
745 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
746 @item Apple Video @tab @tab X @tab fourcc: rpza
747 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
748 @item Cinepak @tab @tab X
749 @item Microsoft RLE @tab @tab X
750 @item Microsoft Video-1 @tab @tab X
751 @item Westwood VQA @tab @tab X
752 @item Id Cinematic Video @tab @tab X @tab used in Quake II
753 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
754 @item FLIC video @tab @tab X
755 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
756 @item VMD Video @tab @tab X @tab used in Sierra VMD files
757 @item MSZH @tab @tab X @tab Part of LCL
758 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
759 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
760 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
763 @code{X} means that the encoding (resp. decoding) is supported.
765 Check at @url{http://www.mplayerhq.hu/~michael/codec-features.html} to
766 get a precise comparison of FFmpeg MPEG4 codec compared to the other
769 @section Audio Codecs
771 @multitable @columnfractions .4 .1 .1 .1 .7
772 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
773 @item MPEG audio layer 2 @tab IX @tab IX
774 @item MPEG audio layer 1/3 @tab IX @tab IX
775 @tab MP3 encoding is supported through the external library LAME
776 @item AC3 @tab IX @tab IX
777 @tab liba52 is used internally for decoding
778 @item Vorbis @tab X @tab X
779 @tab supported through the external library libvorbis
780 @item WMA V1/V2 @tab @tab X
781 @item AAC @tab X @tab X
782 @tab supported through the external library libfaac/libfaad
783 @item Microsoft ADPCM @tab X @tab X
784 @item MS IMA ADPCM @tab X @tab X
785 @item QT IMA ADPCM @tab @tab X
786 @item 4X IMA ADPCM @tab @tab X
787 @item G.726 ADPCM @tab X @tab X
788 @item Duck DK3 IMA ADPCM @tab @tab X
789 @tab used in some Sega Saturn console games
790 @item Duck DK4 IMA ADPCM @tab @tab X
791 @tab used in some Sega Saturn console games
792 @item Westwood Studios IMA ADPCM @tab @tab X
793 @tab used in Westwood Studios games like Command and Conquer
794 @item SMJPEG IMA ADPCM @tab @tab X
795 @tab used in certain Loki game ports
796 @item CD-ROM XA ADPCM @tab @tab X
797 @item CRI ADX ADPCM @tab X @tab X
798 @tab used in Sega Dreamcast games
799 @item Electronic Arts ADPCM @tab @tab X
800 @tab used in various EA titles
801 @item RA144 @tab @tab X
802 @tab Real 14400 bit/s codec
803 @item RA288 @tab @tab X
804 @tab Real 28800 bit/s codec
805 @item RADnet @tab X @tab IX
806 @tab Real lowbitrate AC3 codec, liba52 is used for decoding
807 @item AMR-NB @tab X @tab X
808 @tab supported through an external library
809 @item AMR-WB @tab X @tab X
810 @tab supported through an external library
811 @item DV audio @tab @tab X
812 @item Id RoQ DPCM @tab @tab X
813 @tab used in Quake III, Jedi Knight 2, other computer games
814 @item Interplay MVE DPCM @tab @tab X
815 @tab used in various Interplay computer games
816 @item Xan DPCM @tab @tab X
817 @tab used in Origin's Wing Commander IV AVI files
818 @item Sierra Online DPCM @tab @tab X
819 @tab used in Sierra Online game audio files
820 @item Apple MACE 3 @tab @tab X
821 @item Apple MACE 6 @tab @tab X
822 @item FLAC @tab @tab X
823 @item FFmpeg Sonic @tab X @tab X
824 @tab Experimental lossy/lossless codec
827 @code{X} means that the encoding (resp. decoding) is supported.
829 @code{I} means that an integer only version is available too (ensures highest
830 performances on systems without hardware floating point support).
832 @chapter Platform Specific information
836 ffmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
837 preferred compiler now for ffmpeg. All future optimizations will depend on
838 features only found in GCC 3.2.
844 @subsection Native Windows compilation
847 @item Install the current versions of MSYS and MinGW from
848 @url{http://www.mingw.org/}. You can find detailed installation
849 instructions in the download section and the FAQ.
851 @item If you want to test the FFmpeg Simple Media Player, also download
852 the MinGW development library of SDL 1.2.x
853 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
854 @url{http://www.libsdl.org}. Unpack it in a temporary place, and
855 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
856 directory. Edit the @file{sdl-config} script so that it gives the
857 correct SDL directory when invoked.
859 @item Extract the current version of FFmpeg (the latest release version or the current CVS snapshot whichever is recommended).
861 @item Start the MSYS shell (file @file{msys.bat}).
863 @item Change to the FFMPEG directory and follow
864 the instructions of how to compile ffmpeg (file
865 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
866 suffices. If you have problems using SDL, verify that
867 @file{sdl-config} can be launched from the MSYS command line.
869 @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
877 @item The target @file{make wininstaller} can be used to create a
878 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
879 must be copied in the ffmpeg directory in order to build the
882 @item By using @code{./configure --enable-shared} when configuring ffmpeg,
883 you can build @file{avcodec.dll} and @file{avformat.dll}. With
884 @code{make install} you install the FFmpeg DLLs and the associated
885 headers in @file{Program Files/FFmpeg}.
887 @item Visual C++ compatibility: if you used @code{./configure --enable-shared}
888 when configuring FFmpeg, then FFmpeg tries to use the Microsoft Visual
889 C++ @code{lib} tool to build @code{avcodec.lib} and
890 @code{avformat.lib}. With these libraries, you can link your Visual C++
891 code directly with the FFmpeg DLLs.
895 @subsection Cross compilation for Windows with Linux
897 You must use the MinGW cross compilation tools available at
898 @url{http://www.mingw.org/}.
900 Then configure ffmpeg with the following options:
902 ./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
904 (you can change the cross-prefix according to the prefix choosen for the
907 Then you can easily test ffmpeg with wine
908 (@url{http://www.winehq.com/}).
914 The configure script should guess the configuration itself.
915 Networking support is currently not finished.
916 errno issues fixed by Andrew Bachmann.
920 François Revol - revol at free dot fr - April 2002
922 The configure script should guess the configuration itself,
923 however I still didn't tested building on net_server version of BeOS.
925 ffserver is broken (needs poll() implementation).
927 There is still issues with errno codes, which are negative in BeOs, and
928 that ffmpeg negates when returning. This ends up turning errors into
929 valid results, then crashes.
932 @chapter Developers Guide
936 @item libavcodec is the library containing the codecs (both encoding and
937 decoding). See @file{libavcodec/apiexample.c} to see how to use it.
939 @item libavformat is the library containing the file formats handling (mux and
940 demux code for several formats). See @file{ffplay.c} to use it in a
941 player. See @file{output_example.c} to use it to generate audio or video
946 @section Integrating libavcodec or libavformat in your program
948 You can integrate all the source code of the libraries to link them
949 statically to avoid any version problem. All you need is to provide a
950 'config.mak' and a 'config.h' in the parent directory. See the defines
951 generated by ./configure to understand what is needed.
953 You can use libavcodec or libavformat in your commercial program, but
954 @emph{any patch you make must be published}. The best way to proceed is
955 to send your patches to the ffmpeg mailing list.
958 @section Coding Rules
960 ffmpeg is programmed in the ISO C90 language with a few additional
961 features from ISO C99, namely:
964 the @samp{inline} keyword;
968 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
970 compound literals (@samp{x = (struct s) { 17, 23 @};})
973 These features are supported by all compilers we care about, so we won't
974 accept patches to remove their use unless they absolutely don't impair
975 clarity and performance.
977 All code must compile with gcc 2.95 and gcc 3.3. Currently, ffmpeg also
978 compiles with several other compilers, such as the Compaq ccc compiler
979 or Sun Studio 9, and we would like to keep it that way unless it would
980 be exceedingly involved. To ensure compatibility, please don't use any
981 additional C99 features or gcc extensions. Watch out especially for:
984 mixing statements and declarations;
986 @samp{long long} (use @samp{int64_t} instead);
988 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
990 gcc statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
993 Indent size is 4. The TAB character should not be used.
994 The presentation is the one specified by 'indent -i4 -kr'.
996 Main priority in ffmpeg is simplicity and small code size (=less
999 Comments: use the JavaDoc/Doxygen
1000 format (see examples below) so that a documentation
1001 can be generated automatically. All non trivial functions should have a comment
1002 above it explaining what the function does, even if its just one sentance.
1003 All Structures and their member variables should be documented too.
1016 typedef struct Foobar{
1017 int var1; /**< var1 description */
1018 int var2; ///< var2 description
1019 /** var3 description */
1027 * @param my_parameter description of my_parameter
1028 * @return return value description
1030 int myfunc(int my_parameter)
1034 fprintf and printf are forbidden in libavformat and libavcodec,
1035 please use av_log() instead.
1037 @section Submitting patches
1039 First, (@pxref{Coding Rules}) above if you didn't yet.
1041 When you submit your patch, try to send a unified diff (diff '-up'
1042 option). I cannot read other diffs :-)
1044 Run the regression tests before submitting a patch so that you can
1045 verify that there are no big problems.
1047 Patches should be posted as base64 encoded attachments (or any other
1048 encoding which ensures that the patch wont be trashed during
1049 transmission) to the ffmpeg-devel mailinglist, see
1050 @url{http://lists.sourceforge.net/lists/listinfo/ffmpeg-devel}
1052 It also helps quite a bit if you tell us what the patch does (for example
1053 'replaces lrint by lrintf') , and why (for example '*bsd isnt c99 compliant
1054 and has no lrint()')
1056 We reply to all patches submitted and either apply or reject with some
1057 explanation why, but sometimes we are quite busy so it can take a week or 2
1059 @section Regression tests
1061 Before submitting a patch (or committing with CVS), you should at least
1062 test that you did not break anything.
1064 The regression test build a synthetic video stream and a synthetic
1065 audio stream. Then these are encoded then decoded with all codecs or
1066 formats. The CRC (or MD5) of each generated file is recorded in a
1067 result file. Then a 'diff' is launched with the reference results and
1070 The regression test then goes on to test the ffserver code with a
1071 limited set of streams. It is important that this step runs correctly
1074 Run 'make test' to test all the codecs and formats.
1076 Run 'make fulltest' to test all the codecs, formats and ffserver.
1078 [Of course, some patches may change the regression tests results. In
1079 this case, the regression tests reference results shall be modified