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 -title @var{string}
288 @item -timestamp @var{time}
291 @item -author @var{string}
294 @item -copyright @var{string}
297 @item -comment @var{string}
300 @item -album @var{string}
303 @item -track @var{number}
306 @item -year @var{number}
309 @item -v @var{number}
310 Set the logging verbosity level.
312 @item -target @var{type}
313 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
314 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
315 buffer sizes) are then set automatically. You can just type:
318 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
321 Nevertheless you can specify additional options as long as you know
322 they do not conflict with the standard, as in:
325 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
328 @item -dframes @var{number}
329 Set the number of data frames to record.
331 @item -scodec @var{codec}
332 Force subtitle codec ('copy' to copy stream).
335 Add a new subtitle stream to the current output stream.
337 @item -slang @var{code}
338 Set the ISO 639 language code (3 letters) of the current subtitle stream.
342 @section Video Options
345 @item -b @var{bitrate}
346 Set the video bitrate in bit/s (default = 200 kb/s).
347 @item -vframes @var{number}
348 Set the number of video frames to record.
350 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
352 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
353 The following abbreviations are recognized:
415 @item -aspect @var{aspect}
416 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
417 @item -croptop @var{size}
418 Set top crop band size (in pixels).
419 @item -cropbottom @var{size}
420 Set bottom crop band size (in pixels).
421 @item -cropleft @var{size}
422 Set left crop band size (in pixels).
423 @item -cropright @var{size}
424 Set right crop band size (in pixels).
425 @item -padtop @var{size}
426 Set top pad band size (in pixels).
427 @item -padbottom @var{size}
428 Set bottom pad band size (in pixels).
429 @item -padleft @var{size}
430 Set left pad band size (in pixels).
431 @item -padright @var{size}
432 Set right pad band size (in pixels).
433 @item -padcolor @var{hex_color}
434 Set color of padded bands. The value for padcolor is expressed
435 as a six digit hexadecimal number where the first two digits
436 represent red, the middle two digits green and last two digits
437 blue (default = 000000 (black)).
439 Disable video recording.
440 @item -bt @var{tolerance}
441 Set video bitrate tolerance (in bits, default 4000k).
442 Has a minimum value of: (target_bitrate/target_framerate).
443 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
444 willing to deviate from the target average bitrate value. This is
445 not related to min/max bitrate. Lowering tolerance too much has
446 an adverse effect on quality.
447 @item -maxrate @var{bitrate}
448 Set max video bitrate (in bit/s).
449 Requires -bufsize to be set.
450 @item -minrate @var{bitrate}
451 Set min video bitrate (in bit/s).
452 Most useful in setting up a CBR encode:
454 ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
456 It is of little use elsewise.
457 @item -bufsize @var{size}
458 Set video buffer verifier buffer size (in bits).
459 @item -vcodec @var{codec}
460 Force video codec to @var{codec}. Use the @code{copy} special value to
461 tell that the raw codec data must be copied as is.
463 Use same video quality as source (implies VBR).
466 Select the pass number (1 or 2). It is used to do two-pass
467 video encoding. The statistics of the video are recorded in the first
468 pass into a log file (see also the option -passlogfile),
469 and in the second pass that log file is used to generate the video
470 at the exact requested bitrate.
471 On pass 1, you may just deactivate audio and set output to null,
472 examples for Windows and Unix:
474 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
475 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
478 @item -passlogfile @var{prefix}
479 Set two-pass log file name prefix to @var{prefix}, the default file name
480 prefix is ``ffmpeg2pass''. The complete file name will be
481 @file{PREFIX-N.log}, where N is a number specific to the output
485 Add a new video stream to the current output stream.
489 @section Advanced Video Options
492 @item -pix_fmt @var{format}
493 Set pixel format. Use 'list' as parameter to show all the supported
495 @item -sws_flags @var{flags}
496 Set SwScaler flags (only available when compiled with swscale support).
497 @item -g @var{gop_size}
498 Set the group of pictures size.
500 Use only intra frames.
503 @item -qscale @var{q}
504 Use fixed video quantizer scale (VBR).
506 minimum video quantizer scale (VBR)
508 maximum video quantizer scale (VBR)
510 maximum difference between the quantizer scales (VBR)
511 @item -qblur @var{blur}
512 video quantizer scale blur (VBR) (range 0.0 - 1.0)
513 @item -qcomp @var{compression}
514 video quantizer scale compression (VBR) (default 0.5).
515 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
517 @item -lmin @var{lambda}
518 minimum video lagrange factor (VBR)
519 @item -lmax @var{lambda}
520 max video lagrange factor (VBR)
521 @item -mblmin @var{lambda}
522 minimum macroblock quantizer scale (VBR)
523 @item -mblmax @var{lambda}
524 maximum macroblock quantizer scale (VBR)
526 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
527 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
529 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
532 @item -rc_init_cplx @var{complexity}
533 initial complexity for single pass encoding
534 @item -b_qfactor @var{factor}
535 qp factor between P- and B-frames
536 @item -i_qfactor @var{factor}
537 qp factor between P- and I-frames
538 @item -b_qoffset @var{offset}
539 qp offset between P- and B-frames
540 @item -i_qoffset @var{offset}
541 qp offset between P- and I-frames
542 @item -rc_eq @var{equation}
543 Set rate control equation (@pxref{FFmpeg formula
544 evaluator}) (default = @code{tex^qComp}).
545 @item -rc_override @var{override}
546 rate control override for specific intervals
547 @item -me_method @var{method}
548 Set motion estimation method to @var{method}.
549 Available methods are (from lowest to best quality):
552 Try just the (0, 0) vector.
561 exhaustive search (slow and marginally better than epzs)
564 @item -dct_algo @var{algo}
565 Set DCT algorithm to @var{algo}. Available values are:
568 FF_DCT_AUTO (default)
581 @item -idct_algo @var{algo}
582 Set IDCT algorithm to @var{algo}. Available values are:
585 FF_IDCT_AUTO (default)
609 Set error resilience to @var{n}.
612 FF_ER_CAREFUL (default)
618 FF_ER_VERY_AGGRESSIVE
621 @item -ec @var{bit_mask}
622 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
623 the following values:
626 FF_EC_GUESS_MVS (default = enabled)
628 FF_EC_DEBLOCK (default = enabled)
631 @item -bf @var{frames}
632 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
633 @item -mbd @var{mode}
637 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
639 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
641 FF_MB_DECISION_RD: rate distortion
645 Use four motion vector by macroblock (MPEG-4 only).
647 Use data partitioning (MPEG-4 only).
648 @item -bug @var{param}
649 Work around encoder bugs that are not auto-detected.
650 @item -strict @var{strictness}
651 How strictly to follow the standards.
653 Enable Advanced intra coding (h263+).
655 Enable Unlimited Motion Vector (h263+)
658 Deinterlace pictures.
660 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
661 Use this option if your input file is interlaced and you want
662 to keep the interlaced format for minimum losses.
663 The alternative is to deinterlace the input stream with
664 @option{-deinterlace}, but deinterlacing introduces losses.
666 Calculate PSNR of compressed frames.
668 Dump video coding statistics to @file{vstats_HHMMSS.log}.
669 @item -vstats_file @var{file}
670 Dump video coding statistics to @var{file}.
672 top=1/bottom=0/auto=-1 field first
673 @item -dc @var{precision}
675 @item -vtag @var{fourcc/tag}
676 Force video tag/fourcc.
679 @item -vbsf @var{bitstream_filter}
680 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
682 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
686 @section Audio Options
689 @item -aframes @var{number}
690 Set the number of audio frames to record.
692 Set the audio sampling frequency (default = 44100 Hz).
693 @item -ab @var{bitrate}
694 Set the audio bitrate in bit/s (default = 64k).
695 @item -ac @var{channels}
696 Set the number of audio channels (default = 1).
698 Disable audio recording.
699 @item -acodec @var{codec}
700 Force audio codec to @var{codec}. Use the @code{copy} special value to
701 specify that the raw codec data must be copied as is.
703 Add a new audio track to the output file. If you want to specify parameters,
704 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
706 Mapping will be done automatically, if the number of output streams is equal to
707 the number of input streams, else it will pick the first one that matches. You
708 can override the mapping using @code{-map} as usual.
712 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
714 @item -alang @var{code}
715 Set the ISO 639 language code (3 letters) of the current audio stream.
718 @section Advanced Audio options:
721 @item -atag @var{fourcc/tag}
722 Force audio tag/fourcc.
723 @item -absf @var{bitstream_filter}
724 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
727 @section Subtitle options:
730 @item -scodec @var{codec}
731 Force subtitle codec ('copy' to copy stream).
733 Add a new subtitle stream to the current output stream.
734 @item -slang @var{code}
735 Set the ISO 639 language code (3 letters) of the current subtitle stream.
736 @item -sbsf @var{bitstream_filter}
737 Bitstream filters available are "mov2textsub", "text2movsub".
739 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
743 @section Audio/Video grab options
746 @item -vc @var{channel}
747 Set video grab channel (DV1394 only).
748 @item -tvstd @var{standard}
749 Set television standard (NTSC, PAL (SECAM)).
751 Synchronize read on input.
754 @section Advanced options
757 @item -map @var{input_stream_id}[:@var{sync_stream_id}]
758 Set stream mapping from input streams to output streams.
759 Just enumerate the input streams in the order you want them in the output.
760 @var{sync_stream_id} if specified sets the input stream to sync
762 @item -map_meta_data @var{outfile}:@var{infile}
763 Set meta data information of @var{outfile} from @var{infile}.
765 Print specific debug info.
767 Add timings for benchmarking.
769 Dump each input packet.
771 When dumping packets, also dump the payload.
773 Only use bit exact algorithms (for codec testing).
775 Set RTP payload size in bytes.
777 Read input at native frame rate. Mainly used to simulate a grab device.
779 Loop over the input stream. Currently it works only for image
780 streams. This option is used for automatic FFserver testing.
781 @item -loop_output @var{number_of_times}
782 Repeatedly loop output for formats that support looping such as animated GIF
783 (0 will loop the output infinitely).
784 @item -threads @var{count}
786 @item -vsync @var{parameter}
787 Video sync method. Video will be stretched/squeezed to match the timestamps,
788 it is done by duplicating and dropping frames. With -map you can select from
789 which stream the timestamps should be taken. You can leave either video or
790 audio unchanged and sync the remaining stream(s) to the unchanged one.
791 @item -async @var{samples_per_second}
792 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
793 the parameter is the maximum samples per second by which the audio is changed.
794 -async 1 is a special case where only the start of the audio stream is corrected
795 without any later correction.
797 Copy timestamps from input to output.
799 Finish encoding when the shortest input stream ends.
800 @item -dts_delta_threshold
801 Timestamp discontinuity delta threshold.
802 @item -muxdelay @var{seconds}
803 Set the maximum demux-decode delay.
804 @item -muxpreload @var{seconds}
805 Set the initial demux-decode delay.
808 @section Preset files
810 A preset file contains a sequence of @var{option}=@var{value} pairs,
811 one for each line, specifying a sequence of options which would be
812 awkward to specify on the command line. Lines starting with the hash
813 ('#') character are ignored and are used to provide comments. Check
814 the @file{ffpresets} directory in the FFmpeg source tree for examples.
816 Preset files are specified with the @code{vpre}, @code{apre} and
817 @code{spre} options. The options specified in a preset file are
818 applied to the currently selected codec of the same type as the preset
821 The argument passed to the preset options identifies the preset file
822 to use according to the following rules.
824 First ffmpeg searches for a file named @var{arg}.ffpreset in the
825 directories @file{$HOME/.ffmpeg}, and in the datadir defined at
826 configuration time (usually @file{PREFIX/share/ffmpeg}) in that
827 order. For example, if the argument is @code{libx264-max}, it will
828 search for the file @file{libx264-max.ffpreset}.
830 If no such file is found, then ffmpeg will search for a file named
831 @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
832 directories, where @var{codec_name} is the name of the codec to which
833 the preset file options will be applied. For example, if you select
834 the video codec with @code{-vcodec libx264} and use @code{-vpre max},
835 then it will search for the file @file{libx264-max.ffpreset}.
837 Finally, if the above rules failed and the argument specifies an
838 absolute pathname, ffmpeg will search for that filename. This way you
839 can specify the absolute and complete filename of the preset file, for
840 example @file{./ffpresets/libx264-max.ffpreset}.
842 @node FFmpeg formula evaluator
843 @section FFmpeg formula evaluator
845 When evaluating a rate control string, FFmpeg uses an internal formula
848 The following binary operators are available: @code{+}, @code{-},
849 @code{*}, @code{/}, @code{^}.
851 The following unary operators are available: @code{+}, @code{-},
854 The following statements are available: @code{ld}, @code{st},
857 The following functions are available:
885 The following constants are available:
914 @settitle FFmpeg video converter
917 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
928 The file name can be @file{-} to read from standard input or to write
931 FFmpeg also handles many protocols specified with an URL syntax.
933 Use 'ffmpeg -formats' to see a list of the supported protocols.
935 The protocol @code{http:} is currently used only to communicate with
936 FFserver (see the FFserver documentation). When FFmpeg will be a
937 video player it will also be used for streaming :-)
942 @item For streaming at very low bitrate application, use a low frame rate
943 and a small GOP size. This is especially true for RealVideo where
944 the Linux player does not seem to be very fast, so it can miss
945 frames. An example is:
948 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
951 @item The parameter 'q' which is displayed while encoding is the current
952 quantizer. The value 1 indicates that a very good quality could
953 be achieved. The value 31 indicates the worst quality. If q=31 appears
954 too often, it means that the encoder cannot compress enough to meet
955 your bitrate. You must either increase the bitrate, decrease the
956 frame rate or decrease the frame size.
958 @item If your computer is not fast enough, you can speed up the
959 compression at the expense of the compression ratio. You can use
960 '-me zero' to speed up motion estimation, and '-intra' to disable
961 motion estimation completely (you have only I-frames, which means it
962 is about as good as JPEG compression).
964 @item To have very low audio bitrates, reduce the sampling frequency
965 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
967 @item To have a constant quality (but a variable bitrate), use the option
968 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
971 @item When converting video files, you can use the '-sameq' option which
972 uses the same quality factor in the encoder as in the decoder.
973 It allows almost lossless encoding.