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 grab video and audio from devices given that you specify the input
33 ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
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://linux.bytesex.org/xawtv/}) by Gerd Knorr. You also
39 have to set the audio recording levels correctly with a
44 FFmpeg can grab the X11 display.
47 ffmpeg -f x11grab -s cif -i :0.0 /tmp/out.mpg
50 0.0 is display.screen number of your X11 server, same as
51 the DISPLAY environment variable.
54 ffmpeg -f x11grab -s cif -i :0.0+10,20 /tmp/out.mpg
57 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
58 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
60 @section Video and Audio file format conversion
62 * FFmpeg can use any supported file format and protocol as input:
66 * You can use YUV files as input:
69 ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
72 It will use the files:
74 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
75 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
78 The Y files use twice the resolution of the U and V files. They are
79 raw files, without header. They can be generated by all decent video
80 decoders. You must specify the size of the image with the @option{-s} option
81 if FFmpeg cannot guess it.
83 * You can input from a raw YUV420P file:
86 ffmpeg -i /tmp/test.yuv /tmp/out.avi
89 test.yuv is a file containing raw YUV planar data. Each frame is composed
90 of the Y plane followed by the U and V planes at half vertical and
91 horizontal resolution.
93 * You can output to a raw YUV420P file:
96 ffmpeg -i mydivx.avi hugefile.yuv
99 * You can set several input files and output files:
102 ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
105 Converts the audio file a.wav and the raw YUV video file a.yuv
108 * You can also do audio and video conversions at the same time:
111 ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
114 Converts a.wav to MPEG audio at 22050 Hz sample rate.
116 * You can encode to several formats at the same time and define a
117 mapping from input stream to output streams:
120 ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
123 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
124 file:index' specifies which input stream is used for each output
125 stream, in the order of the definition of output streams.
127 * You can transcode decrypted VOBs:
130 ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 128k snatch.avi
133 This is a typical DVD ripping example; the input is a VOB file, the
134 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
135 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
136 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
137 input video. Furthermore, the audio stream is MP3-encoded so you need
138 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
139 The mapping is particularly useful for DVD transcoding
140 to get the desired audio language.
142 NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
144 * You can extract images from a video, or create a video from many images:
146 For extracting images from a video:
148 ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
151 This will extract one video frame per second from the video and will
152 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
153 etc. Images will be rescaled to fit the new WxH values.
155 If you want to extract just a limited number of frames, you can use the
156 above command in combination with the -vframes or -t option, or in
157 combination with -ss to start extracting from a certain point in time.
159 For creating a video from many images:
161 ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
164 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
165 composed of three digits padded with zeroes to express the sequence
166 number. It is the same syntax supported by the C printf function, but
167 only formats accepting a normal integer are suitable.
169 * You can put many streams of the same type in the output:
172 ffmpeg -i test1.avi -i test2.avi -vcodec copy -acodec copy -vcodec copy -acodec copy test12.avi -newvideo -newaudio
175 In addition to the first video and audio streams, the resulting
176 output file @file{test12.avi} will contain the second video
177 and the second audio stream found in the input streams list.
179 The @code{-newvideo}, @code{-newaudio} and @code{-newsubtitle}
180 options have to be specified immediately after the name of the output
181 file to which you want to add them.
188 The generic syntax is:
191 @c man begin SYNOPSIS
192 ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
195 @c man begin DESCRIPTION
196 As a general rule, options are applied to the next specified
197 file. Therefore, order is important, and you can have the same
198 option on the command line multiple times. Each occurrence is
199 then applied to the next input or output file.
201 * To set the video bitrate of the output file to 64kbit/s:
203 ffmpeg -i input.avi -b 64k output.avi
206 * To force the frame rate of the output file to 24 fps:
208 ffmpeg -i input.avi -r 24 output.avi
211 * To force the frame rate of the input file (valid for raw formats only)
212 to 1 fps and the frame rate of the output file to 24 fps:
214 ffmpeg -r 1 -i input.m2v -r 24 output.avi
217 The format option may be needed for raw input files.
219 By default, FFmpeg tries to convert as losslessly as possible: It
220 uses the same audio and video parameters for the outputs as the one
221 specified for the inputs.
225 @section Main options
238 Show available formats, codecs, bitstream filters, protocols, and frame size and frame rate abbreviations.
240 The fields preceding the format and codec names have the following meanings:
247 Video/audio/subtitle codec
249 Codec supports slices
251 Codec supports direct rendering
253 Codec can handle input truncated at random locations instead of only at frame boundaries
259 @item -i @var{filename}
263 Overwrite output files.
265 @item -t @var{duration}
266 Restrict the transcoded/captured video sequence
267 to the duration specified in seconds.
268 @code{hh:mm:ss[.xxx]} syntax is also supported.
270 @item -fs @var{limit_size}
271 Set the file size limit.
273 @item -ss @var{position}
274 Seek to given time position in seconds.
275 @code{hh:mm:ss[.xxx]} syntax is also supported.
277 @item -itsoffset @var{offset}
278 Set the input time offset in seconds.
279 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
280 This option affects all the input files that follow it.
281 The offset is added to the timestamps of the input files.
282 Specifying a positive offset means that the corresponding
283 streams are delayed by 'offset' seconds.
285 @item -timestamp @var{time}
288 @item -metadata @var{key}=@var{value}
289 Set a metadata key/value pair.
291 For example, for setting the title in the output file:
293 ffmpeg -i in.avi -metadata title="my title" out.flv
296 @item -v @var{number}
297 Set the logging verbosity level.
299 @item -loglevel @var{loglevel}
300 Set the logging level used by the library.
301 @var{loglevel} is a number or a string containing one of the following values:
313 @item -target @var{type}
314 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
315 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
316 buffer sizes) are then set automatically. You can just type:
319 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
322 Nevertheless you can specify additional options as long as you know
323 they do not conflict with the standard, as in:
326 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
329 @item -dframes @var{number}
330 Set the number of data frames to record.
332 @item -scodec @var{codec}
333 Force subtitle codec ('copy' to copy stream).
336 Add a new subtitle stream to the current output stream.
338 @item -slang @var{code}
339 Set the ISO 639 language code (3 letters) of the current subtitle stream.
343 @section Video Options
346 @item -b @var{bitrate}
347 Set the video bitrate in bit/s (default = 200 kb/s).
348 @item -vframes @var{number}
349 Set the number of video frames to record.
351 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
353 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
354 The following abbreviations are recognized:
416 @item -aspect @var{aspect}
417 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
418 @item -croptop @var{size}
419 Set top crop band size (in pixels).
420 @item -cropbottom @var{size}
421 Set bottom crop band size (in pixels).
422 @item -cropleft @var{size}
423 Set left crop band size (in pixels).
424 @item -cropright @var{size}
425 Set right crop band size (in pixels).
426 @item -padtop @var{size}
427 Set top pad band size (in pixels).
428 @item -padbottom @var{size}
429 Set bottom pad band size (in pixels).
430 @item -padleft @var{size}
431 Set left pad band size (in pixels).
432 @item -padright @var{size}
433 Set right pad band size (in pixels).
434 @item -padcolor @var{hex_color}
435 Set color of padded bands. The value for padcolor is expressed
436 as a six digit hexadecimal number where the first two digits
437 represent red, the middle two digits green and last two digits
438 blue (default = 000000 (black)).
440 Disable video recording.
441 @item -bt @var{tolerance}
442 Set video bitrate tolerance (in bits, default 4000k).
443 Has a minimum value of: (target_bitrate/target_framerate).
444 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
445 willing to deviate from the target average bitrate value. This is
446 not related to min/max bitrate. Lowering tolerance too much has
447 an adverse effect on quality.
448 @item -maxrate @var{bitrate}
449 Set max video bitrate (in bit/s).
450 Requires -bufsize to be set.
451 @item -minrate @var{bitrate}
452 Set min video bitrate (in bit/s).
453 Most useful in setting up a CBR encode:
455 ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
457 It is of little use elsewise.
458 @item -bufsize @var{size}
459 Set video buffer verifier buffer size (in bits).
460 @item -vcodec @var{codec}
461 Force video codec to @var{codec}. Use the @code{copy} special value to
462 tell that the raw codec data must be copied as is.
464 Use same video quality as source (implies VBR).
467 Select the pass number (1 or 2). It is used to do two-pass
468 video encoding. The statistics of the video are recorded in the first
469 pass into a log file (see also the option -passlogfile),
470 and in the second pass that log file is used to generate the video
471 at the exact requested bitrate.
472 On pass 1, you may just deactivate audio and set output to null,
473 examples for Windows and Unix:
475 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
476 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
479 @item -passlogfile @var{prefix}
480 Set two-pass log file name prefix to @var{prefix}, the default file name
481 prefix is ``ffmpeg2pass''. The complete file name will be
482 @file{PREFIX-N.log}, where N is a number specific to the output
486 Add a new video stream to the current output stream.
490 @section Advanced Video Options
493 @item -pix_fmt @var{format}
494 Set pixel format. Use 'list' as parameter to show all the supported
496 @item -sws_flags @var{flags}
497 Set SwScaler flags (only available when compiled with swscale support).
498 @item -g @var{gop_size}
499 Set the group of pictures size.
501 Use only intra frames.
504 @item -qscale @var{q}
505 Use fixed video quantizer scale (VBR).
507 minimum video quantizer scale (VBR)
509 maximum video quantizer scale (VBR)
511 maximum difference between the quantizer scales (VBR)
512 @item -qblur @var{blur}
513 video quantizer scale blur (VBR) (range 0.0 - 1.0)
514 @item -qcomp @var{compression}
515 video quantizer scale compression (VBR) (default 0.5).
516 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
518 @item -lmin @var{lambda}
519 minimum video lagrange factor (VBR)
520 @item -lmax @var{lambda}
521 max video lagrange factor (VBR)
522 @item -mblmin @var{lambda}
523 minimum macroblock quantizer scale (VBR)
524 @item -mblmax @var{lambda}
525 maximum macroblock quantizer scale (VBR)
527 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
528 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
530 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
533 @item -rc_init_cplx @var{complexity}
534 initial complexity for single pass encoding
535 @item -b_qfactor @var{factor}
536 qp factor between P- and B-frames
537 @item -i_qfactor @var{factor}
538 qp factor between P- and I-frames
539 @item -b_qoffset @var{offset}
540 qp offset between P- and B-frames
541 @item -i_qoffset @var{offset}
542 qp offset between P- and I-frames
543 @item -rc_eq @var{equation}
544 Set rate control equation (@pxref{FFmpeg formula
545 evaluator}) (default = @code{tex^qComp}).
546 @item -rc_override @var{override}
547 rate control override for specific intervals
548 @item -me_method @var{method}
549 Set motion estimation method to @var{method}.
550 Available methods are (from lowest to best quality):
553 Try just the (0, 0) vector.
562 exhaustive search (slow and marginally better than epzs)
565 @item -dct_algo @var{algo}
566 Set DCT algorithm to @var{algo}. Available values are:
569 FF_DCT_AUTO (default)
582 @item -idct_algo @var{algo}
583 Set IDCT algorithm to @var{algo}. Available values are:
586 FF_IDCT_AUTO (default)
610 Set error resilience to @var{n}.
613 FF_ER_CAREFUL (default)
619 FF_ER_VERY_AGGRESSIVE
622 @item -ec @var{bit_mask}
623 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
624 the following values:
627 FF_EC_GUESS_MVS (default = enabled)
629 FF_EC_DEBLOCK (default = enabled)
632 @item -bf @var{frames}
633 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
634 @item -mbd @var{mode}
638 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
640 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
642 FF_MB_DECISION_RD: rate distortion
646 Use four motion vector by macroblock (MPEG-4 only).
648 Use data partitioning (MPEG-4 only).
649 @item -bug @var{param}
650 Work around encoder bugs that are not auto-detected.
651 @item -strict @var{strictness}
652 How strictly to follow the standards.
654 Enable Advanced intra coding (h263+).
656 Enable Unlimited Motion Vector (h263+)
659 Deinterlace pictures.
661 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
662 Use this option if your input file is interlaced and you want
663 to keep the interlaced format for minimum losses.
664 The alternative is to deinterlace the input stream with
665 @option{-deinterlace}, but deinterlacing introduces losses.
667 Calculate PSNR of compressed frames.
669 Dump video coding statistics to @file{vstats_HHMMSS.log}.
670 @item -vstats_file @var{file}
671 Dump video coding statistics to @var{file}.
673 top=1/bottom=0/auto=-1 field first
674 @item -dc @var{precision}
676 @item -vtag @var{fourcc/tag}
677 Force video tag/fourcc.
680 @item -vbsf @var{bitstream_filter}
681 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
683 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
687 @section Audio Options
690 @item -aframes @var{number}
691 Set the number of audio frames to record.
693 Set the audio sampling frequency (default = 44100 Hz).
694 @item -ab @var{bitrate}
695 Set the audio bitrate in bit/s (default = 64k).
696 @item -ac @var{channels}
697 Set the number of audio channels (default = 1).
699 Disable audio recording.
700 @item -acodec @var{codec}
701 Force audio codec to @var{codec}. Use the @code{copy} special value to
702 specify that the raw codec data must be copied as is.
704 Add a new audio track to the output file. If you want to specify parameters,
705 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
707 Mapping will be done automatically, if the number of output streams is equal to
708 the number of input streams, else it will pick the first one that matches. You
709 can override the mapping using @code{-map} as usual.
713 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
715 @item -alang @var{code}
716 Set the ISO 639 language code (3 letters) of the current audio stream.
719 @section Advanced Audio options:
722 @item -atag @var{fourcc/tag}
723 Force audio tag/fourcc.
724 @item -absf @var{bitstream_filter}
725 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
728 @section Subtitle options:
731 @item -scodec @var{codec}
732 Force subtitle codec ('copy' to copy stream).
734 Add a new subtitle stream to the current output stream.
735 @item -slang @var{code}
736 Set the ISO 639 language code (3 letters) of the current subtitle stream.
737 @item -sbsf @var{bitstream_filter}
738 Bitstream filters available are "mov2textsub", "text2movsub".
740 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
744 @section Audio/Video grab options
747 @item -vc @var{channel}
748 Set video grab channel (DV1394 only).
749 @item -tvstd @var{standard}
750 Set television standard (NTSC, PAL (SECAM)).
752 Synchronize read on input.
755 @section Advanced options
758 @item -map @var{input_stream_id}[:@var{sync_stream_id}]
759 Set stream mapping from input streams to output streams.
760 Just enumerate the input streams in the order you want them in the output.
761 @var{sync_stream_id} if specified sets the input stream to sync
763 @item -map_meta_data @var{outfile}:@var{infile}
764 Set meta data information of @var{outfile} from @var{infile}.
766 Print specific debug info.
768 Add timings for benchmarking.
770 Dump each input packet.
772 When dumping packets, also dump the payload.
774 Only use bit exact algorithms (for codec testing).
776 Set RTP payload size in bytes.
778 Read input at native frame rate. Mainly used to simulate a grab device.
780 Loop over the input stream. Currently it works only for image
781 streams. This option is used for automatic FFserver testing.
782 @item -loop_output @var{number_of_times}
783 Repeatedly loop output for formats that support looping such as animated GIF
784 (0 will loop the output infinitely).
785 @item -threads @var{count}
787 @item -vsync @var{parameter}
788 Video sync method. Video will be stretched/squeezed to match the timestamps,
789 it is done by duplicating and dropping frames. With -map you can select from
790 which stream the timestamps should be taken. You can leave either video or
791 audio unchanged and sync the remaining stream(s) to the unchanged one.
792 @item -async @var{samples_per_second}
793 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
794 the parameter is the maximum samples per second by which the audio is changed.
795 -async 1 is a special case where only the start of the audio stream is corrected
796 without any later correction.
798 Copy timestamps from input to output.
800 Finish encoding when the shortest input stream ends.
801 @item -dts_delta_threshold
802 Timestamp discontinuity delta threshold.
803 @item -muxdelay @var{seconds}
804 Set the maximum demux-decode delay.
805 @item -muxpreload @var{seconds}
806 Set the initial demux-decode delay.
809 @section Preset files
811 A preset file contains a sequence of @var{option}=@var{value} pairs,
812 one for each line, specifying a sequence of options which would be
813 awkward to specify on the command line. Lines starting with the hash
814 ('#') character are ignored and are used to provide comments. Check
815 the @file{ffpresets} directory in the FFmpeg source tree for examples.
817 Preset files are specified with the @code{vpre}, @code{apre} and
818 @code{spre} options. The options specified in a preset file are
819 applied to the currently selected codec of the same type as the preset
822 The argument passed to the preset options identifies the preset file
823 to use according to the following rules.
825 First ffmpeg searches for a file named @var{arg}.ffpreset in the
826 directories @file{$HOME/.ffmpeg}, and in the datadir defined at
827 configuration time (usually @file{PREFIX/share/ffmpeg}) in that
828 order. For example, if the argument is @code{libx264-max}, it will
829 search for the file @file{libx264-max.ffpreset}.
831 If no such file is found, then ffmpeg will search for a file named
832 @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
833 directories, where @var{codec_name} is the name of the codec to which
834 the preset file options will be applied. For example, if you select
835 the video codec with @code{-vcodec libx264} and use @code{-vpre max},
836 then it will search for the file @file{libx264-max.ffpreset}.
838 Finally, if the above rules failed and the argument specifies an
839 absolute pathname, ffmpeg will search for that filename. This way you
840 can specify the absolute and complete filename of the preset file, for
841 example @file{./ffpresets/libx264-max.ffpreset}.
843 @anchor{FFmpeg formula evaluator}
844 @section FFmpeg formula evaluator
846 When evaluating a rate control string, FFmpeg uses an internal formula
849 The following binary operators are available: @code{+}, @code{-},
850 @code{*}, @code{/}, @code{^}.
852 The following unary operators are available: @code{+}, @code{-},
855 The following statements are available: @code{ld}, @code{st},
858 The following functions are available:
886 The following constants are available:
915 @settitle FFmpeg video converter
918 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
929 The file name can be @file{-} to read from standard input or to write
932 FFmpeg also handles many protocols specified with an URL syntax.
934 Use 'ffmpeg -formats' to see a list of the supported protocols.
936 The protocol @code{http:} is currently used only to communicate with
937 FFserver (see the FFserver documentation). When FFmpeg will be a
938 video player it will also be used for streaming :-)
943 @item For streaming at very low bitrate application, use a low frame rate
944 and a small GOP size. This is especially true for RealVideo where
945 the Linux player does not seem to be very fast, so it can miss
946 frames. An example is:
949 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
952 @item The parameter 'q' which is displayed while encoding is the current
953 quantizer. The value 1 indicates that a very good quality could
954 be achieved. The value 31 indicates the worst quality. If q=31 appears
955 too often, it means that the encoder cannot compress enough to meet
956 your bitrate. You must either increase the bitrate, decrease the
957 frame rate or decrease the frame size.
959 @item If your computer is not fast enough, you can speed up the
960 compression at the expense of the compression ratio. You can use
961 '-me zero' to speed up motion estimation, and '-intra' to disable
962 motion estimation completely (you have only I-frames, which means it
963 is about as good as JPEG compression).
965 @item To have very low audio bitrates, reduce the sampling frequency
966 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
968 @item To have a constant quality (but a variable bitrate), use the option
969 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
972 @item When converting video files, you can use the '-sameq' option which
973 uses the same quality factor in the encoder as in the decoder.
974 It allows almost lossless encoding.