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 parameters that can possibly be
18 derived automatically. You usually only have to specify the target
21 FFmpeg can also convert from any sample rate to any other, and resize
22 video on the fly with a high quality polyphase filter.
27 @section Video and Audio grabbing
29 FFmpeg can use a video4linux compatible video source and any Open Sound
36 Note that you must activate the right video source and channel before
37 launching FFmpeg with any TV viewer such as xawtv
38 (@url{http://bytesex.org/xawtv/}) by Gerd Knorr. You also
39 have to set the audio recording levels correctly with a
42 @section Video and Audio file format conversion
44 * FFmpeg can use any supported file format and protocol as input:
48 * You can use YUV files as input:
51 ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
54 It will use the files:
56 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
57 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
60 The Y files use twice the resolution of the U and V files. They are
61 raw files, without header. They can be generated by all decent video
62 decoders. You must specify the size of the image with the @option{-s} option
63 if FFmpeg cannot guess it.
65 * You can input from a raw YUV420P file:
68 ffmpeg -i /tmp/test.yuv /tmp/out.avi
71 test.yuv is a file containing raw YUV planar data. Each frame is composed
72 of the Y plane followed by the U and V planes at half vertical and
73 horizontal resolution.
75 * You can output to a raw YUV420P file:
78 ffmpeg -i mydivx.avi hugefile.yuv
81 * You can set several input files and output files:
84 ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
87 Converts the audio file a.wav and the raw YUV video file a.yuv
90 * You can also do audio and video conversions at the same time:
93 ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
96 Converts a.wav to MPEG audio at 22050Hz sample rate.
98 * You can encode to several formats at the same time and define a
99 mapping from input stream to output streams:
102 ffmpeg -i /tmp/a.wav -ab 64 /tmp/a.mp2 -ab 128 /tmp/b.mp2 -map 0:0 -map 0:0
105 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
106 file:index' specifies which input stream is used for each output
107 stream, in the order of the definition of output streams.
109 * You can transcode decrypted VOBs
112 ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec mp3 -ab 128 snatch.avi
115 This is a typical DVD ripping example; the input is a VOB file, the
116 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
117 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
118 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
119 input video. Furthermore, the audio stream is MP3-encoded so you need
120 to enable LAME support by passing @code{--enable-mp3lame} to configure.
121 The mapping is particularly useful for DVD transcoding
122 to get the desired audio language.
124 NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
131 The generic syntax is:
134 @c man begin SYNOPSIS
135 ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
138 @c man begin DESCRIPTION
139 If no input file is given, audio/video grabbing is done.
141 As a general rule, options are applied to the next specified
142 file. For example, if you give the @option{-b 64k} option, it sets the video
143 bitrate of the next file. The format option may be needed for raw input
146 By default, FFmpeg tries to convert as losslessly as possible: It
147 uses the same audio and video parameters for the outputs as the one
148 specified for the inputs.
152 @section Main options
162 Show available formats, codecs, protocols, ...
171 Overwrite output files.
174 Set the recording time in seconds.
175 @code{hh:mm:ss[.xxx]} syntax is also supported.
178 Seek to given time position in seconds.
179 @code{hh:mm:ss[.xxx]} syntax is also supported.
187 @item -copyright string
190 @item -comment string
200 Specify target file type ("vcd", "svcd", "dvd", "dv", "pal-vcd",
201 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
202 buffer sizes) are then set automatically. You can just type:
205 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
208 Nevertheless you can specify additional options as long as you know
209 they do not conflict with the standard, as in:
212 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
215 @item -itsoffset offset
216 Set the input time offset in seconds.
217 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
218 This option affects all the input files that follow it.
219 The offset is added to the timestamps of the input files.
220 Specifying a positive offset means that the corresponding
221 streams are delayed by 'offset' seconds.
225 @section Video Options
229 Set the video bitrate in bit/s (default = 200 kb/s).
231 Set frame rate (default = 25).
233 Set frame size. The format is @samp{wxh} (default = 160x128).
234 The following abbreviations are recognized:
247 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
249 Set top crop band size (in pixels).
250 @item -cropbottom size
251 Set bottom crop band size (in pixels).
253 Set left crop band size (in pixels).
254 @item -cropright size
255 Set right crop band size (in pixels).
257 Set top pad band size (in pixels).
258 @item -padbottom size
259 Set bottom pad band size (in pixels).
261 Set left pad band size (in pixels).
263 Set right pad band size (in pixels).
264 @item -padcolor (hex color)
265 Set color of padded bands. The value for padcolor is expressed
266 as a six digit hexadecimal number where the first two digits
267 represent red, the middle two digits green and last two digits
268 blue (default = 000000 (black)).
270 Disable video recording.
272 Set video bitrate tolerance (in bit/s).
273 @item -maxrate bitrate
274 Set max video bitrate tolerance (in bit/s).
275 @item -minrate bitrate
276 Set min video bitrate tolerance (in bit/s).
278 Set rate control buffer size (in bits).
280 Force video codec to @var{codec}. Use the @code{copy} special value to
281 tell that the raw codec data must be copied as is.
283 Use same video quality as source (implies VBR).
286 Select the pass number (1 or 2). It is useful to do two pass
287 encoding. The statistics of the video are recorded in the first
288 pass and the video is generated at the exact requested bitrate
291 @item -passlogfile file
292 Set two pass logfile name to @var{file}.
296 @section Advanced Video Options
300 Set the group of pictures size.
302 Use only intra frames.
304 Use fixed video quantizer scale (VBR).
306 minimum video quantizer scale (VBR)
308 maximum video quantizer scale (VBR)
310 maximum difference between the quantizer scales (VBR)
312 video quantizer scale blur (VBR)
313 @item -qcomp compression
314 video quantizer scale compression (VBR)
317 minimum video lagrange factor (VBR)
319 max video lagrange factor (VBR)
321 minimum macroblock quantizer scale (VBR)
323 maximum macroblock quantizer scale (VBR)
325 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
326 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
328 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
331 @item -rc_init_cplx complexity
332 initial complexity for single pass encoding
333 @item -b_qfactor factor
334 qp factor between P- and B-frames
335 @item -i_qfactor factor
336 qp factor between P- and I-frames
337 @item -b_qoffset offset
338 qp offset between P- and B-frames
339 @item -i_qoffset offset
340 qp offset between P- and I-frames
341 @item -rc_eq equation
342 Set rate control equation (@pxref{FFmpeg formula
343 evaluator}) (default = @code{tex^qComp}).
344 @item -rc_override override
345 rate control override for specific intervals
347 Set motion estimation method to @var{method}.
348 Available methods are (from lowest to best quality):
351 Try just the (0, 0) vector.
358 exhaustive search (slow and marginally better than epzs)
362 Set DCT algorithm to @var{algo}. Available values are:
365 FF_DCT_AUTO (default)
378 @item -idct_algo algo
379 Set IDCT algorithm to @var{algo}. Available values are:
382 FF_IDCT_AUTO (default)
406 Set error resilience to @var{n}.
409 FF_ER_CAREFUL (default)
415 FF_ER_VERY_AGGRESSIVE
419 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
420 the following values:
423 FF_EC_GUESS_MVS (default = enabled)
425 FF_EC_DEBLOCK (default = enabled)
429 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
434 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
436 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
438 FF_MB_DECISION_RD: rate distortion
442 Use four motion vector by macroblock (MPEG-4 only).
444 Use data partitioning (MPEG-4 only).
446 Work around encoder bugs that are not auto-detected.
447 @item -strict strictness
448 How strictly to follow the standards.
450 Enable Advanced intra coding (h263+).
452 Enable Unlimited Motion Vector (h263+)
455 Deinterlace pictures.
457 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
458 Use this option if your input file is interlaced and you want
459 to keep the interlaced format for minimum losses.
460 The alternative is to deinterlace the input stream with
461 @option{-deinterlace}, but deinterlacing introduces losses.
463 Calculate PSNR of compressed frames.
465 Dump video coding statistics to @file{vstats_HHMMSS.log}.
467 Insert video processing @var{module}. @var{module} contains the module
468 name and its parameters separated by spaces.
471 @section Audio Options
475 Set the audio sampling frequency (default = 44100 Hz).
477 Set the audio bitrate in kbit/s (default = 64).
479 Set the number of audio channels (default = 1).
481 Disable audio recording.
483 Force audio codec to @var{codec}. Use the @code{copy} special value to
484 specify that the raw codec data must be copied as is.
487 @section Audio/Video grab options
491 sEt video grab device (e.g. @file{/dev/video0}).
493 Set video grab channel (DV1394 only).
494 @item -tvstd standard
495 Set television standard (NTSC, PAL (SECAM)).
499 Set audio device (e.g. @file{/dev/dsp}).
502 @section Advanced options
505 @item -map input stream id[:input stream id]
506 Set stream mapping from input streams to output streams.
507 Just enumerate the input streams in the order you want them in the output.
508 [input stream id] sets the (input) stream to sync against.
510 Print specific debug info.
512 Add timings for benchmarking.
514 Dump each input packet.
516 Only use bit exact algorithms (for codec testing).
518 Set packet size in bits.
520 Read input at native frame rate. Mainly used to simulate a grab device.
522 Loop over the input stream. Currently it works only for image
523 streams. This option is used for automatic FFserver testing.
524 @item -loop_output number_of_times
525 Repeatedly loop output for formats that support looping such as animated GIF
526 (0 will loop the output infinitely).
527 @item -vsync parameter
528 Video sync method. Video will be stretched/squeezed to match the timestamps,
529 it is done by duplicating and dropping frames. With -map you can select from
530 which stream the timestamps should be taken. You can leave either video or
531 audio unchanged and sync the remaining stream(s) to the unchanged one.
532 @item -async samples_per_second
533 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
534 the parameter is the maximum samples per second by which the audio is changed.
535 -async 1 is a special case where only the start of the audio stream is corrected
536 without any later correction.
539 @node FFmpeg formula evaluator
540 @section FFmpeg formula evaluator
542 When evaluating a rate control string, FFmpeg uses an internal formula
545 The following binary operators are available: @code{+}, @code{-},
546 @code{*}, @code{/}, @code{^}.
548 The following unary operators are available: @code{+}, @code{-},
551 The following functions are available:
573 The following constants are available:
602 @settitle FFmpeg video converter
605 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
616 The filename can be @file{-} to read from standard input or to write
619 FFmpeg also handles many protocols specified with an URL syntax.
621 Use 'ffmpeg -formats' to see a list of the supported protocols.
623 The protocol @code{http:} is currently used only to communicate with
624 FFserver (see the FFserver documentation). When FFmpeg will be a
625 video player it will also be used for streaming :-)
630 @item For streaming at very low bitrate application, use a low frame rate
631 and a small GOP size. This is especially true for RealVideo where
632 the Linux player does not seem to be very fast, so it can miss
633 frames. An example is:
636 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
639 @item The parameter 'q' which is displayed while encoding is the current
640 quantizer. The value 1 indicates that a very good quality could
641 be achieved. The value 31 indicates the worst quality. If q=31 appears
642 too often, it means that the encoder cannot compress enough to meet
643 your bitrate. You must either increase the bitrate, decrease the
644 frame rate or decrease the frame size.
646 @item If your computer is not fast enough, you can speed up the
647 compression at the expense of the compression ratio. You can use
648 '-me zero' to speed up motion estimation, and '-intra' to disable
649 motion estimation completely (you have only I-frames, which means it
650 is about as good as JPEG compression).
652 @item To have very low audio bitrates, reduce the sampling frequency
653 (down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
655 @item To have a constant quality (but a variable bitrate), use the option
656 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
659 @item When converting video files, you can use the '-sameq' option which
660 uses the same quality factor in the encoder as in the decoder.
661 It allows almost lossless encoding.
665 @chapter Supported File Formats and Codecs
667 You can use the @code{-formats} option to have an exhaustive list.
669 @section File Formats
671 FFmpeg supports the following file formats through the @code{libavformat}
674 @multitable @columnfractions .4 .1 .1 .4
675 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
676 @item MPEG audio @tab X @tab X
677 @item MPEG-1 systems @tab X @tab X
678 @tab muxed audio and video
679 @item MPEG-2 PS @tab X @tab X
680 @tab also known as @code{VOB} file
681 @item MPEG-2 TS @tab @tab X
682 @tab also known as DVB Transport Stream
683 @item ASF@tab X @tab X
684 @item AVI@tab X @tab X
685 @item WAV@tab X @tab X
686 @item Macromedia Flash@tab X @tab X
687 @tab Only embedded audio is decoded.
688 @item FLV @tab X @tab X
689 @tab Macromedia Flash video files
690 @item Real Audio and Video @tab X @tab X
691 @item Raw AC3 @tab X @tab X
692 @item Raw MJPEG @tab X @tab X
693 @item Raw MPEG video @tab X @tab X
694 @item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
695 @item Raw CRI ADX audio @tab X @tab X
696 @item Raw Shorten audio @tab @tab X
697 @item SUN AU format @tab X @tab X
698 @item NUT @tab X @tab X @tab NUT Open Container Format
699 @item QuickTime @tab X @tab X
700 @item MPEG-4 @tab X @tab X
701 @tab MPEG-4 is a variant of QuickTime.
702 @item Raw MPEG4 video @tab X @tab X
703 @item DV @tab X @tab X
704 @item 4xm @tab @tab X
705 @tab 4X Technologies format, used in some games.
706 @item Playstation STR @tab @tab X
707 @item Id RoQ @tab @tab X
708 @tab Used in Quake III, Jedi Knight 2, other computer games.
709 @item Interplay MVE @tab @tab X
710 @tab Format used in various Interplay computer games.
711 @item WC3 Movie @tab @tab X
712 @tab Multimedia format used in Origin's Wing Commander III computer game.
713 @item Sega FILM/CPK @tab @tab X
714 @tab Used in many Sega Saturn console games.
715 @item Westwood Studios VQA/AUD @tab @tab X
716 @tab Multimedia formats used in Westwood Studios games.
717 @item Id Cinematic (.cin) @tab @tab X
718 @tab Used in Quake II.
719 @item FLIC format @tab @tab X
721 @item Sierra VMD @tab @tab X
722 @tab Used in Sierra CD-ROM games.
723 @item Sierra Online @tab @tab X
724 @tab .sol files used in Sierra Online games.
725 @item Matroska @tab @tab X
726 @item Electronic Arts Multimedia @tab @tab X
727 @tab Used in various EA games; files have extensions like WVE and UV2.
728 @item Nullsoft Video (NSV) format @tab @tab X
729 @item ADTS AAC audio @tab X @tab X
730 @item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
731 @item American Laser Games MM @tab @tab X
732 @tab Multimedia format used in games like Mad Dog McCree
733 @item AVS @tab @tab X
734 @tab Multimedia format used by the Creature Shock game.
735 @item Smacker @tab @tab X
736 @tab Multimedia format used by many games.
737 @item GXF @tab X @tab X
738 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
739 @item CIN @tab @tab X
740 @tab Multimedia format used by Delphine Software games.
741 @item MXF @tab @tab X
742 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
743 @item SEQ @tab @tab X
744 @tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
747 @code{X} means that encoding (resp. decoding) is supported.
749 @section Image Formats
751 FFmpeg can read and write images for each frame of a video sequence. The
752 following image formats are supported:
754 @multitable @columnfractions .4 .1 .1 .4
755 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
756 @item PGM, PPM @tab X @tab X
757 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
758 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
759 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
760 @item .Y.U.V @tab X @tab X @tab one raw file per component
761 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
762 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
763 @item Targa @tab @tab X @tab Targa (.TGA) image format.
764 @item SGI @tab X @tab X @tab SGI RGB image format
767 @code{X} means that encoding (resp. decoding) is supported.
769 @section Video Codecs
771 @multitable @columnfractions .4 .1 .1 .4
772 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
773 @item MPEG-1 video @tab X @tab X
774 @item MPEG-2 video @tab X @tab X
775 @item MPEG-4 @tab X @tab X
776 @item MSMPEG4 V1 @tab X @tab X
777 @item MSMPEG4 V2 @tab X @tab X
778 @item MSMPEG4 V3 @tab X @tab X
779 @item WMV7 @tab X @tab X
780 @item WMV8 @tab X @tab X @tab not completely working
781 @item H.261 @tab X @tab X
782 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
783 @item H.264 @tab @tab X
784 @item RealVideo 1.0 @tab X @tab X
785 @item RealVideo 2.0 @tab X @tab X
786 @item MJPEG @tab X @tab X
787 @item lossless MJPEG @tab X @tab X
788 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
789 @item Apple MJPEG-B @tab @tab X
790 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
791 @item DV @tab X @tab X
792 @item HuffYUV @tab X @tab X
793 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
794 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
795 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
796 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
797 @item Creative YUV @tab @tab X @tab fourcc: CYUV
798 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
799 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
800 @item On2 VP3 @tab @tab X @tab still experimental
801 @item On2 VP5 @tab @tab X @tab fourcc: VP50
802 @item On2 VP6 @tab @tab X @tab fourcc: VP62
803 @item Theora @tab @tab X @tab still experimental
804 @item Intel Indeo 3 @tab @tab X
805 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
806 @item Flash Screen Video @tab @tab X @tab fourcc: FSV1
807 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
808 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
809 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
810 @item 4X Video @tab @tab X @tab Used in certain computer games.
811 @item Sony Playstation MDEC @tab @tab X
812 @item Id RoQ @tab @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
813 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
814 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
815 @item Apple Animation @tab @tab X @tab fourcc: 'rle '
816 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
817 @item Apple Video @tab @tab X @tab fourcc: rpza
818 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
819 @item Cinepak @tab @tab X
820 @item Microsoft RLE @tab @tab X
821 @item Microsoft Video-1 @tab @tab X
822 @item Westwood VQA @tab @tab X
823 @item Id Cinematic Video @tab @tab X @tab Used in Quake II.
824 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
825 @item FLIC video @tab @tab X
826 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
827 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
828 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
829 @item MSZH @tab @tab X @tab Part of LCL
830 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
831 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
832 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
833 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
834 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
835 @item LOCO @tab @tab X @tab
836 @item Winnov WNV1 @tab @tab X @tab
837 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
838 @item Fraps FPS1 @tab @tab X @tab
839 @item CamStudio @tab @tab X @tab fourcc: CSCD
840 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
841 @item ZMBV @tab @tab X @tab
842 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
843 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
844 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
845 @item KMVC @tab @tab X @tab Codec used in Worms games.
846 @item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
847 @item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
848 @item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
851 @code{X} means that encoding (resp. decoding) is supported.
853 @section Audio Codecs
855 @multitable @columnfractions .4 .1 .1 .1 .7
856 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
857 @item MPEG audio layer 2 @tab IX @tab IX
858 @item MPEG audio layer 1/3 @tab IX @tab IX
859 @tab MP3 encoding is supported through the external library LAME.
860 @item AC3 @tab IX @tab IX
861 @tab liba52 is used internally for decoding.
862 @item Vorbis @tab X @tab X
863 @tab Supported through the external library libvorbis.
864 @item WMA V1/V2 @tab @tab X
865 @item AAC @tab X @tab X
866 @tab Supported through the external library libfaac/libfaad.
867 @item Microsoft ADPCM @tab X @tab X
868 @item MS IMA ADPCM @tab X @tab X
869 @item QT IMA ADPCM @tab @tab X
870 @item 4X IMA ADPCM @tab @tab X
871 @item G.726 ADPCM @tab X @tab X
872 @item Duck DK3 IMA ADPCM @tab @tab X
873 @tab Used in some Sega Saturn console games.
874 @item Duck DK4 IMA ADPCM @tab @tab X
875 @tab Used in some Sega Saturn console games.
876 @item Westwood Studios IMA ADPCM @tab @tab X
877 @tab Used in Westwood Studios games like Command and Conquer.
878 @item SMJPEG IMA ADPCM @tab @tab X
879 @tab Used in certain Loki game ports.
880 @item CD-ROM XA ADPCM @tab @tab X
881 @item CRI ADX ADPCM @tab X @tab X
882 @tab Used in Sega Dreamcast games.
883 @item Electronic Arts ADPCM @tab @tab X
884 @tab Used in various EA titles.
885 @item Creative ADPCM @tab @tab X
886 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
887 @item RA144 @tab @tab X
888 @tab Real 14400 bit/s codec
889 @item RA288 @tab @tab X
890 @tab Real 28800 bit/s codec
891 @item RADnet @tab X @tab IX
892 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
893 @item AMR-NB @tab X @tab X
894 @tab Supported through an external library.
895 @item AMR-WB @tab X @tab X
896 @tab Supported through an external library.
897 @item DV audio @tab @tab X
898 @item Id RoQ DPCM @tab @tab X
899 @tab Used in Quake III, Jedi Knight 2, other computer games.
900 @item Interplay MVE DPCM @tab @tab X
901 @tab Used in various Interplay computer games.
902 @item Xan DPCM @tab @tab X
903 @tab Used in Origin's Wing Commander IV AVI files.
904 @item Sierra Online DPCM @tab @tab X
905 @tab Used in Sierra Online game audio files.
906 @item Apple MACE 3 @tab @tab X
907 @item Apple MACE 6 @tab @tab X
908 @item FLAC lossless audio @tab @tab X
909 @item Shorten lossless audio @tab @tab X
910 @item Apple lossless audio @tab @tab X
911 @tab QuickTime fourcc 'alac'
912 @item FFmpeg Sonic @tab X @tab X
913 @tab experimental lossy/lossless codec
914 @item Qdesign QDM2 @tab @tab X
915 @tab there are still some distortions
916 @item Real COOK @tab @tab X
917 @tab All versions except 5.1 are supported
918 @item DSP Group TrueSpeech @tab @tab X
919 @item True Audio (TTA) @tab @tab X
920 @item Smacker Audio @tab @tab X
921 @item WavPack Audio @tab @tab X
922 @item Cin Audio @tab @tab X
923 @tab Codec used in Delphine Software games.
926 @code{X} means that encoding (resp. decoding) is supported.
928 @code{I} means that an integer-only version is available, too (ensures high
929 performance on systems without hardware floating point support).
931 @chapter Platform Specific information
935 FFmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
936 preferred compiler now for FFmpeg. All future optimizations will depend on
937 features only found in GCC 3.2.
941 BSD make will not build FFmpeg, you need to install and use GNU Make
946 @subsection Native Windows compilation
949 @item Install the current versions of MSYS and MinGW from
950 @url{http://www.mingw.org/}. You can find detailed installation
951 instructions in the download section and the FAQ.
953 @item If you want to test the FFplay, also download
954 the MinGW development library of SDL 1.2.x
955 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
956 @url{http://www.libsdl.org}. Unpack it in a temporary directory, and
957 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
958 directory. Edit the @file{sdl-config} script so that it gives the
959 correct SDL directory when invoked.
961 @item Extract the current version of FFmpeg.
963 @item Start the MSYS shell (file @file{msys.bat}).
965 @item Change to the FFmpeg directory and follow
966 the instructions of how to compile FFmpeg (file
967 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
968 suffices. If you have problems using SDL, verify that
969 @file{sdl-config} can be launched from the MSYS command line.
971 @item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
972 @file{make install}. Don't forget to copy @file{SDL.dll} to the place
973 you launch @file{ffplay} from.
980 @item The target @file{make wininstaller} can be used to create a
981 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
982 must be copied to the FFmpeg directory in order to build the
985 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
986 you can build @file{avcodec.dll} and @file{avformat.dll}. With
987 @code{make install} you install the FFmpeg DLLs and the associated
988 headers in @file{Program Files/FFmpeg}.
990 @item Visual C++ compatibility: If you used @code{./configure --enable-shared}
991 when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
992 C++ @code{lib} tool to build @code{avcodec.lib} and
993 @code{avformat.lib}. With these libraries you can link your Visual C++
994 code directly with the FFmpeg DLLs (see below).
998 @subsection Visual C++ compatibility
1000 FFmpeg will not compile under Visual C++ -- and it has too many
1001 dependencies on the GCC compiler to make a port viable. However,
1002 if you want to use the FFmpeg libraries in your own applications,
1003 you can still compile those applications using Visual C++. An
1004 important restriction to this is that you have to use the
1005 dynamically linked versions of the FFmpeg libraries (i.e. the
1006 DLLs), and you have to make sure that Visual-C++-compatible
1007 import libraries are created during the FFmpeg build process.
1009 This description of how to use the FFmpeg libraries with Visual C++ is
1010 based on Visual C++ 2005 Express Edition Beta 2. If you have a different
1011 version, you might have to modify the procedures slightly.
1013 Here are the step-by-step instructions for building the FFmpeg libraries
1014 so they can be used with Visual C++:
1018 @item Install Visual C++ (if you haven't done so already).
1020 @item Install MinGW and MSYS as described above.
1022 @item Add a call to @file{vcvars32.bat} (which sets up the environment
1023 variables for the Visual C++ tools) as the first line of
1024 @file{msys.bat}. The standard location for @file{vcvars32.bat} is
1025 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
1026 and the standard location for @file{msys.bat} is
1027 @file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
1028 following line as the first line of @file{msys.bat}:
1030 @code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
1032 @item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
1033 If you get a help message with the command line options of @code{link.exe},
1034 this means your environment variables are set up correctly, the
1035 Microsoft linker is on the path and will be used by FFmpeg to
1036 create Visual-C++-compatible import libraries.
1038 @item Extract the current version of FFmpeg and change to the FFmpeg directory.
1040 @item Type the command
1041 @code{./configure --enable-shared --disable-static --enable-memalign-hack}
1042 to configure and, if that didn't produce any errors,
1043 type @code{make} to build FFmpeg.
1045 @item The subdirectories @file{libavformat}, @file{libavcodec}, and
1046 @file{libavutil} should now contain the files @file{avformat.dll},
1047 @file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
1048 @file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
1049 DLLs to your System32 directory (typically @file{C:\Windows\System32}).
1053 And here is how to use these libraries with Visual C++:
1057 @item Create a new console application ("File / New / Project") and then
1058 select "Win32 Console Application". On the appropriate page of the
1059 Application Wizard, uncheck the "Precompiled headers" option.
1061 @item Write the source code for your application, or, for testing, just
1062 copy the code from an existing sample application into the source file
1063 that Visual C++ has already created for you. (Note that your source
1064 filehas to have a @code{.cpp} extension; otherwise, Visual C++ won't
1065 compile the FFmpeg headers correctly because in C mode, it doesn't
1066 recognize the @code{inline} keyword.) For example, you can copy
1067 @file{output_example.c} from the FFmpeg distribution (but you will
1068 have to make minor modifications so the code will compile under
1071 @item Open the "Project / Properties" dialog box. In the "Configuration"
1072 combo box, select "All Configurations" so that the changes you make will
1073 affect both debug and release builds. In the tree view on the left hand
1074 side, select "C/C++ / General", then edit the "Additional Include
1075 Directories" setting to contain the complete paths to the
1076 @file{libavformat}, @file{libavcodec}, and @file{libavutil}
1077 subdirectories of your FFmpeg directory. Note that the directories have
1078 to be separated using semicolons. Now select "Linker / General" from the
1079 tree view and edit the "Additional Library Directories" setting to
1080 contain the same three directories.
1082 @item Still in the "Project / Properties" dialog box, select "Linker / Input"
1083 from the tree view, then add the files @file{avformat.lib},
1084 @file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1085 Dependencies". Note that the names of the libraries have to be separated
1088 @item Now, select "C/C++ / Code Generation" from the tree view. Select
1089 "Debug" in the "Configuration" combo box. Make sure that "Runtime
1090 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1091 the "Configuration" combo box and make sure that "Runtime Library" is
1092 set to "Multi-threaded DLL".
1094 @item Click "OK" to close the "Project / Properties" dialog box and build
1095 the application. Hopefully, it should compile and run cleanly. If you
1096 used @file{output_example.c} as your sample application, you will get a
1097 few compiler errors, but they are easy to fix. The first type of error
1098 occurs because Visual C++ doesn't allow an @code{int} to be converted to
1099 an @code{enum} without a cast. To solve the problem, insert the required
1100 casts (this error occurs once for a @code{CodecID} and once for a
1101 @code{CodecType}). The second type of error occurs because C++ requires
1102 the return value of @code{malloc} to be cast to the exact type of the
1103 pointer it is being assigned to. Visual C++ will complain that, for
1104 example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1105 an explicit cast. So insert an explicit cast in these places to silence
1106 the compiler. The third type of error occurs because the @code{snprintf}
1107 library function is called @code{_snprintf} under Visual C++. So just
1108 add an underscore to fix the problem. With these changes,
1109 @file{output_example.c} should compile under Visual C++, and the
1110 resulting executable should produce valid video files.
1114 @subsection Cross compilation for Windows with Linux
1116 You must use the MinGW cross compilation tools available at
1117 @url{http://www.mingw.org/}.
1119 Then configure FFmpeg with the following options:
1121 ./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
1123 (you can change the cross-prefix according to the prefix chosen for the
1126 Then you can easily test FFmpeg with Wine
1127 (@url{http://www.winehq.com/}).
1129 @subsection Compilation under Cygwin
1131 Cygwin works very much like Unix.
1133 Just install your Cygwin with all the "Base" packages, plus the
1134 following "Devel" ones:
1136 binutils, gcc-core, make, subversion
1139 Do not install binutils-20060709-1 (they are buggy on shared builds);
1140 use binutils-20050610-1 instead.
1145 ./configure --enable-static --disable-shared
1148 to make a static build or
1151 ./configure --enable-shared --disable-static
1154 to build shared libraries.
1156 If you want to build FFmpeg with additional libraries, download Cygwin
1157 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
1158 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
1159 (@url{http://cygwinports.dotsrc.org/}).
1161 @subsection Crosscompilation for Windows under Cygwin
1163 With Cygwin you can create Windows binaries that don't need the cygwin1.dll.
1165 Just install your Cygwin as explained before, plus these additional
1168 gcc-mingw-core, mingw-runtime, mingw-zlib
1171 and add some special flags to your configure invocation.
1173 For a static build run
1175 ./configure --enable-mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1178 and for a build with shared libraries
1180 ./configure --enable-mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1187 The configure script should guess the configuration itself.
1188 Networking support is currently not finished.
1189 errno issues fixed by Andrew Bachmann.
1193 François Revol - revol at free dot fr - April 2002
1195 The configure script should guess the configuration itself,
1196 however I still didn't test building on the net_server version of BeOS.
1198 FFserver is broken (needs poll() implementation).
1200 There are still issues with errno codes, which are negative in BeOS, and
1201 that FFmpeg negates when returning. This ends up turning errors into
1202 valid results, then crashes.
1205 @chapter Developers Guide
1209 @item libavcodec is the library containing the codecs (both encoding and
1210 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
1212 @item libavformat is the library containing the file format handling (mux and
1213 demux code for several formats). Look at @file{ffplay.c} to use it in a
1214 player. See @file{output_example.c} to use it to generate audio or video
1219 @section Integrating libavcodec or libavformat in your program
1221 You can integrate all the source code of the libraries to link them
1222 statically to avoid any version problem. All you need is to provide a
1223 'config.mak' and a 'config.h' in the parent directory. See the defines
1224 generated by ./configure to understand what is needed.
1226 You can use libavcodec or libavformat in your commercial program, but
1227 @emph{any patch you make must be published}. The best way to proceed is
1228 to send your patches to the FFmpeg mailing list.
1231 @section Coding Rules
1233 FFmpeg is programmed in the ISO C90 language with a few additional
1234 features from ISO C99, namely:
1237 the @samp{inline} keyword;
1241 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1243 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1246 These features are supported by all compilers we care about, so we won't
1247 accept patches to remove their use unless they absolutely don't impair
1248 clarity and performance.
1250 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1251 compiles with several other compilers, such as the Compaq ccc compiler
1252 or Sun Studio 9, and we would like to keep it that way unless it would
1253 be exceedingly involved. To ensure compatibility, please don't use any
1254 additional C99 features or GCC extensions. Especially watch out for:
1257 mixing statements and declarations;
1259 @samp{long long} (use @samp{int64_t} instead);
1261 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1263 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1267 The presentation is the one specified by 'indent -i4 -kr -nut'.
1268 The TAB character is forbidden outside of Makefiles as is any
1269 form of trailing whitespace. Commits containing either will be
1270 rejected by the Subversion repository.
1272 Main priority in FFmpeg is simplicity and small code size (=less
1275 Comments: Use the JavaDoc/Doxygen
1276 format (see examples below) so that code documentation
1277 can be generated automatically. All nontrivial functions should have a comment
1278 above them explaining what the function does, even if it's just one sentence.
1279 All structures and their member variables should be documented, too.
1292 typedef struct Foobar@{
1293 int var1; /**< var1 description */
1294 int var2; ///< var2 description
1295 /** var3 description */
1303 * @@param my_parameter description of my_parameter
1304 * @@return return value description
1306 int myfunc(int my_parameter)
1310 fprintf and printf are forbidden in libavformat and libavcodec,
1311 please use av_log() instead.
1313 @section Development Policy
1317 You must not commit code which breaks FFmpeg! (Meaning unfinished but
1318 enabled code which breaks compilation or compiles but does not work or
1319 breaks the regression tests)
1320 You can commit unfinished stuff (for testing etc), but it must be disabled
1321 (#ifdef etc) by default so it does not interfere with other developers'
1324 You don't have to over-test things. If it works for you, and you think it
1325 should work for others, then commit. If your code has problems
1326 (portability, triggers compiler bugs, unusual environment etc) they will be
1327 reported and eventually fixed.
1329 Do not commit unrelated changes together, split them into self-contained
1332 Do not change behavior of the program (renaming options etc) without
1333 first discussing it on the ffmpeg-devel mailing list. Do not remove
1334 functionality from the code. Just improve!
1336 Note: Redundant code can be removed.
1338 Do not commit changes to the build system (Makefiles, configure script)
1339 which change behavior, defaults etc, without asking first. The same
1340 applies to compiler warning fixes, trivial looking fixes and to code
1341 maintained by other developers. We usually have a reason for doing things
1342 the way we do. Send your changes as patches to the ffmpeg-devel mailing
1343 list, and if the code maintainers say OK, you may commit. This does not
1344 apply to files you wrote and/or maintain.
1346 We refuse source indentation and other cosmetic changes if they are mixed
1347 with functional changes, such commits will be rejected and removed. Every
1348 developer has his own indentation style, you should not change it. Of course
1349 if you (re)write something, you can use your own style, even though we would
1350 prefer if the indentation throughout FFmpeg was consistent (Many projects
1351 force a given indentation style - we don't.). If you really need to make
1352 indentation changes (try to avoid this), separate them strictly from real
1355 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1356 then either do NOT change the indentation of the inner part within (don't
1357 move it to the right)! or do so in a separate commit
1359 Always fill out the commit log message. Describe in a few lines what you
1360 changed and why. You can refer to mailing list postings if you fix a
1361 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1363 If you apply a patch by someone else, include the name and email address in
1364 the log message. Since the ffmpeg-cvslog mailing list is publicly
1365 archived you should add some SPAM protection to the email address. Send an
1366 answer to ffmpeg-devel (or wherever you got the patch from) saying that
1367 you applied the patch.
1369 Do NOT commit to code actively maintained by others without permission.
1370 Send a patch to ffmpeg-devel instead. If noone answers within a reasonable
1371 timeframe (12h for build failures and security fixes, 3 days small changes,
1372 1 week for big patches) then commit your patch if you think it's OK.
1373 Also note, the maintainer can simply ask for more time to review!
1375 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1376 are sent there and reviewed by all the other developers. Bugs and possible
1377 improvements or general questions regarding commits are discussed there. We
1378 expect you to react if problems with your code are uncovered.
1380 Update the documentation if you change behavior or add features. If you are
1381 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1382 maintainer(s) will review and commit your stuff.
1384 Never write to unallocated memory, never write over the end of arrays,
1385 always check values read from some untrusted source before using them
1386 as array index or other risky things.
1388 Remember to check if you need to bump versions for the specific libav
1389 parts (libavutil, libavcodec, libavformat) you are changing. You need
1390 to change the version integer and the version string.
1391 Incrementing the first component means no backward compatibility to
1392 previous versions (e.g. removal of a function from the public API).
1393 Incrementing the second component means backward compatible change
1394 (e.g. addition of a function to the public API).
1395 Incrementing the third component means a noteworthy binary compatible
1396 change (e.g. encoder bug fix that matters for the decoder).
1398 If you add a new codec, remember to update the changelog, add it to
1399 the supported codecs table in the documentation and bump the second
1400 component of the @file{libavcodec} version number appropriately. If
1401 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
1405 We think our rules are not too hard. If you have comments, contact us.
1407 Note, these rules are mostly borrowed from the MPlayer project.
1409 @section Submitting patches
1411 First, (@pxref{Coding Rules}) above if you didn't yet.
1413 When you submit your patch, try to send a unified diff (diff '-up'
1414 option). I cannot read other diffs :-)
1416 Also please do not submit patches which contain several unrelated changes.
1417 Split them into individual self-contained patches; this makes reviewing
1420 Run the regression tests before submitting a patch so that you can
1421 verify that there are no big problems.
1423 Patches should be posted as base64 encoded attachments (or any other
1424 encoding which ensures that the patch won't be trashed during
1425 transmission) to the ffmpeg-devel mailing list, see
1426 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1428 It also helps quite a bit if you tell us what the patch does (for example
1429 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1430 and has no lrint()')
1432 We reply to all submitted patches and either apply or reject with some
1433 explanation why, but sometimes we are quite busy so it can take a week or two.
1435 @section Regression tests
1437 Before submitting a patch (or committing to the repository), you should at least
1438 test that you did not break anything.
1440 The regression tests build a synthetic video stream and a synthetic
1441 audio stream. These are then encoded and decoded with all codecs or
1442 formats. The CRC (or MD5) of each generated file is recorded in a
1443 result file. A 'diff' is launched to compare the reference results and
1446 The regression tests then go on to test the FFserver code with a
1447 limited set of streams. It is important that this step runs correctly
1450 Run 'make test' to test all the codecs and formats.
1452 Run 'make fulltest' to test all the codecs, formats and FFserver.
1454 [Of course, some patches may change the results of the regression tests. In
1455 this case, the reference results of the regression tests shall be modified