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://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:
147 ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
150 This will extract one video frame per second from the video and will
151 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
152 etc. Images will be rescaled to fit the new WxH values.
154 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
155 composed of three digits padded with zeroes to express the sequence
156 number. It is the same syntax supported by the C printf function, but
157 only formats accepting a normal integer are suitable.
159 If you want to extract just a limited number of frames, you can use the
160 above command in combination with the -vframes or -t option, or in
161 combination with -ss to start extracting from a certain point in time.
163 * You can put many streams of the same type in the output:
166 ffmpeg -i test1.avi -i test2.avi -vcodec copy -acodec copy -vcodec copy -acodec copy test12.avi -newvideo -newaudio
169 In addition to the first video and audio streams, the resulting
170 output file @file{test12.avi} will contain the second video
171 and the second audio stream found in the input streams list.
173 The @code{-newvideo}, @code{-newaudio} and @code{-newsubtitle}
174 options have to be specified immediately after the name of the output
175 file to which you want to add them.
182 The generic syntax is:
185 @c man begin SYNOPSIS
186 ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
189 @c man begin DESCRIPTION
190 As a general rule, options are applied to the next specified
191 file. Therefore, order is important, and you can have the same
192 option on the command line multiple times. Each occurrence is
193 then applied to the next input or output file.
195 * To set the video bitrate of the output file to 64kbit/s:
197 ffmpeg -i input.avi -b 64k output.avi
200 * To force the frame rate of the output file to 24 fps:
202 ffmpeg -i input.avi -r 24 output.avi
205 * To force the frame rate of the input file (valid for raw formats only)
206 to 1 fps and the frame rate of the output file to 24 fps:
208 ffmpeg -r 1 -i input.m2v -r 24 output.avi
211 The format option may be needed for raw input files.
213 By default, FFmpeg tries to convert as losslessly as possible: It
214 uses the same audio and video parameters for the outputs as the one
215 specified for the inputs.
219 @section Main options
232 Show available formats, codecs, protocols, ...
237 @item -i @var{filename}
241 Overwrite output files.
243 @item -t @var{duration}
244 Restrict the transcoded/captured video sequence
245 to the duration specified in seconds.
246 @code{hh:mm:ss[.xxx]} syntax is also supported.
248 @item -fs @var{limit_size}
249 Set the file size limit.
251 @item -ss @var{position}
252 Seek to given time position in seconds.
253 @code{hh:mm:ss[.xxx]} syntax is also supported.
255 @item -itsoffset @var{offset}
256 Set the input time offset in seconds.
257 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
258 This option affects all the input files that follow it.
259 The offset is added to the timestamps of the input files.
260 Specifying a positive offset means that the corresponding
261 streams are delayed by 'offset' seconds.
263 @item -title @var{string}
266 @item -timestamp @var{time}
269 @item -author @var{string}
272 @item -copyright @var{string}
275 @item -comment @var{string}
278 @item -album @var{string}
281 @item -track @var{number}
284 @item -year @var{number}
287 @item -v @var{number}
288 Set the logging verbosity level.
290 @item -target @var{type}
291 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
292 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
293 buffer sizes) are then set automatically. You can just type:
296 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
299 Nevertheless you can specify additional options as long as you know
300 they do not conflict with the standard, as in:
303 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
306 @item -dframes @var{number}
307 Set the number of data frames to record.
309 @item -scodec @var{codec}
310 Force subtitle codec ('copy' to copy stream).
313 Add a new subtitle stream to the current output stream.
315 @item -slang @var{code}
316 Set the ISO 639 language code (3 letters) of the current subtitle stream.
320 @section Video Options
323 @item -b @var{bitrate}
324 Set the video bitrate in bit/s (default = 200 kb/s).
325 @item -vframes @var{number}
326 Set the number of video frames to record.
328 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
330 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
331 The following abbreviations are recognized:
391 @item -aspect @var{aspect}
392 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
393 @item -croptop @var{size}
394 Set top crop band size (in pixels).
395 @item -cropbottom @var{size}
396 Set bottom crop band size (in pixels).
397 @item -cropleft @var{size}
398 Set left crop band size (in pixels).
399 @item -cropright @var{size}
400 Set right crop band size (in pixels).
401 @item -padtop @var{size}
402 Set top pad band size (in pixels).
403 @item -padbottom @var{size}
404 Set bottom pad band size (in pixels).
405 @item -padleft @var{size}
406 Set left pad band size (in pixels).
407 @item -padright @var{size}
408 Set right pad band size (in pixels).
409 @item -padcolor @var{hex_color}
410 Set color of padded bands. The value for padcolor is expressed
411 as a six digit hexadecimal number where the first two digits
412 represent red, the middle two digits green and last two digits
413 blue (default = 000000 (black)).
415 Disable video recording.
416 @item -bt @var{tolerance}
417 Set video bitrate tolerance (in bits, default 4000k).
418 Has a minimum value of: (target_bitrate/target_framerate).
419 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
420 willing to deviate from the target average bitrate value. This is
421 not related to min/max bitrate. Lowering tolerance too much has
422 an adverse effect on quality.
423 @item -maxrate @var{bitrate}
424 Set max video bitrate (in bit/s).
425 Requires -bufsize to be set.
426 @item -minrate @var{bitrate}
427 Set min video bitrate (in bit/s).
428 Most useful in setting up a CBR encode:
430 ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
432 It is of little use elsewise.
433 @item -bufsize @var{size}
434 Set video buffer verifier buffer size (in bits).
435 @item -vcodec @var{codec}
436 Force video codec to @var{codec}. Use the @code{copy} special value to
437 tell that the raw codec data must be copied as is.
439 Use same video quality as source (implies VBR).
442 Select the pass number (1 or 2). It is used to do two-pass
443 video encoding. The statistics of the video are recorded in the first
444 pass into a log file (see also the option -passlogfile),
445 and in the second pass that log file is used to generate the video
446 at the exact requested bitrate.
447 On pass 1, you may just deactivate audio and set output to null,
448 examples for Windows and Unix:
450 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
451 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
454 @item -passlogfile @var{file}
455 Set two-pass log file name to @var{file}. Default name is
456 @file{ffmpeg2pass-N.log}, where N is a number specific to the output
460 Add a new video stream to the current output stream.
464 @section Advanced Video Options
467 @item -pix_fmt @var{format}
468 Set pixel format. Use 'list' as parameter to show all the supported
470 @item -sws_flags @var{flags}
471 Set SwScaler flags (only available when compiled with swscale support).
472 @item -g @var{gop_size}
473 Set the group of pictures size.
475 Use only intra frames.
478 @item -qscale @var{q}
479 Use fixed video quantizer scale (VBR).
481 minimum video quantizer scale (VBR)
483 maximum video quantizer scale (VBR)
485 maximum difference between the quantizer scales (VBR)
486 @item -qblur @var{blur}
487 video quantizer scale blur (VBR) (range 0.0 - 1.0)
488 @item -qcomp @var{compression}
489 video quantizer scale compression (VBR) (default 0.5).
490 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
492 @item -lmin @var{lambda}
493 minimum video lagrange factor (VBR)
494 @item -lmax @var{lambda}
495 max video lagrange factor (VBR)
496 @item -mblmin @var{lambda}
497 minimum macroblock quantizer scale (VBR)
498 @item -mblmax @var{lambda}
499 maximum macroblock quantizer scale (VBR)
501 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
502 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
504 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
507 @item -rc_init_cplx @var{complexity}
508 initial complexity for single pass encoding
509 @item -b_qfactor @var{factor}
510 qp factor between P- and B-frames
511 @item -i_qfactor @var{factor}
512 qp factor between P- and I-frames
513 @item -b_qoffset @var{offset}
514 qp offset between P- and B-frames
515 @item -i_qoffset @var{offset}
516 qp offset between P- and I-frames
517 @item -rc_eq @var{equation}
518 Set rate control equation (@pxref{FFmpeg formula
519 evaluator}) (default = @code{tex^qComp}).
520 @item -rc_override @var{override}
521 rate control override for specific intervals
522 @item -me_method @var{method}
523 Set motion estimation method to @var{method}.
524 Available methods are (from lowest to best quality):
527 Try just the (0, 0) vector.
536 exhaustive search (slow and marginally better than epzs)
539 @item -dct_algo @var{algo}
540 Set DCT algorithm to @var{algo}. Available values are:
543 FF_DCT_AUTO (default)
556 @item -idct_algo @var{algo}
557 Set IDCT algorithm to @var{algo}. Available values are:
560 FF_IDCT_AUTO (default)
584 Set error resilience to @var{n}.
587 FF_ER_CAREFUL (default)
593 FF_ER_VERY_AGGRESSIVE
596 @item -ec @var{bit_mask}
597 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
598 the following values:
601 FF_EC_GUESS_MVS (default = enabled)
603 FF_EC_DEBLOCK (default = enabled)
606 @item -bf @var{frames}
607 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
608 @item -mbd @var{mode}
612 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
614 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
616 FF_MB_DECISION_RD: rate distortion
620 Use four motion vector by macroblock (MPEG-4 only).
622 Use data partitioning (MPEG-4 only).
623 @item -bug @var{param}
624 Work around encoder bugs that are not auto-detected.
625 @item -strict @var{strictness}
626 How strictly to follow the standards.
628 Enable Advanced intra coding (h263+).
630 Enable Unlimited Motion Vector (h263+)
633 Deinterlace pictures.
635 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
636 Use this option if your input file is interlaced and you want
637 to keep the interlaced format for minimum losses.
638 The alternative is to deinterlace the input stream with
639 @option{-deinterlace}, but deinterlacing introduces losses.
641 Calculate PSNR of compressed frames.
643 Dump video coding statistics to @file{vstats_HHMMSS.log}.
644 @item -vstats_file @var{file}
645 Dump video coding statistics to @var{file}.
646 @item -vhook @var{module}
647 Insert video processing @var{module}. @var{module} contains the module
648 name and its parameters separated by spaces.
650 top=1/bottom=0/auto=-1 field first
651 @item -dc @var{precision}
653 @item -vtag @var{fourcc/tag}
654 Force video tag/fourcc.
657 @item -vbsf @var{bitstream_filter}
658 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
660 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
664 @section Audio Options
667 @item -aframes @var{number}
668 Set the number of audio frames to record.
670 Set the audio sampling frequency (default = 44100 Hz).
671 @item -ab @var{bitrate}
672 Set the audio bitrate in bit/s (default = 64k).
673 @item -ac @var{channels}
674 Set the number of audio channels (default = 1).
676 Disable audio recording.
677 @item -acodec @var{codec}
678 Force audio codec to @var{codec}. Use the @code{copy} special value to
679 specify that the raw codec data must be copied as is.
681 Add a new audio track to the output file. If you want to specify parameters,
682 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
684 Mapping will be done automatically, if the number of output streams is equal to
685 the number of input streams, else it will pick the first one that matches. You
686 can override the mapping using @code{-map} as usual.
690 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
692 @item -alang @var{code}
693 Set the ISO 639 language code (3 letters) of the current audio stream.
696 @section Advanced Audio options:
699 @item -atag @var{fourcc/tag}
700 Force audio tag/fourcc.
701 @item -absf @var{bitstream_filter}
702 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
705 @section Subtitle options:
708 @item -scodec @var{codec}
709 Force subtitle codec ('copy' to copy stream).
711 Add a new subtitle stream to the current output stream.
712 @item -slang @var{code}
713 Set the ISO 639 language code (3 letters) of the current subtitle stream.
714 @item -sbsf @var{bitstream_filter}
715 Bitstream filters available are "mov2textsub", "text2movsub".
717 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
721 @section Audio/Video grab options
724 @item -vc @var{channel}
725 Set video grab channel (DV1394 only).
726 @item -tvstd @var{standard}
727 Set television standard (NTSC, PAL (SECAM)).
729 Synchronize read on input.
732 @section Advanced options
735 @item -map @var{input_stream_id}[:@var{sync_stream_id}]
736 Set stream mapping from input streams to output streams.
737 Just enumerate the input streams in the order you want them in the output.
738 @var{sync_stream_id} if specified sets the input stream to sync
740 @item -map_meta_data @var{outfile}:@var{infile}
741 Set meta data information of @var{outfile} from @var{infile}.
743 Print specific debug info.
745 Add timings for benchmarking.
747 Dump each input packet.
749 When dumping packets, also dump the payload.
751 Only use bit exact algorithms (for codec testing).
753 Set packet size in bits.
755 Read input at native frame rate. Mainly used to simulate a grab device.
757 Loop over the input stream. Currently it works only for image
758 streams. This option is used for automatic FFserver testing.
759 @item -loop_output @var{number_of_times}
760 Repeatedly loop output for formats that support looping such as animated GIF
761 (0 will loop the output infinitely).
762 @item -threads @var{count}
764 @item -vsync @var{parameter}
765 Video sync method. Video will be stretched/squeezed to match the timestamps,
766 it is done by duplicating and dropping frames. With -map you can select from
767 which stream the timestamps should be taken. You can leave either video or
768 audio unchanged and sync the remaining stream(s) to the unchanged one.
769 @item -async @var{samples_per_second}
770 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
771 the parameter is the maximum samples per second by which the audio is changed.
772 -async 1 is a special case where only the start of the audio stream is corrected
773 without any later correction.
775 Copy timestamps from input to output.
777 Finish encoding when the shortest input stream ends.
778 @item -dts_delta_threshold
779 Timestamp discontinuity delta threshold.
780 @item -muxdelay @var{seconds}
781 Set the maximum demux-decode delay.
782 @item -muxpreload @var{seconds}
783 Set the initial demux-decode delay.
786 @section Preset files
788 A preset file contains a sequence of @var{option}=@var{value} pairs,
789 one for each line, specifying a sequence of options which would be
790 awkward to specify on the command line. Lines starting with the hash
791 ('#') character are ignored and are used to provide comments. Check
792 the @file{ffpresets} directory in the FFmpeg source tree for examples.
794 Preset files are specified with the @code{vpre}, @code{apre} and
795 @code{spre} options. The options specified in a preset file are
796 applied to the currently selected codec of the same type as the preset
799 The argument passed to the preset options identifies the preset file
800 to use according to the following rules.
802 First ffmpeg searches for a file named @var{arg}.ffpreset in the
803 directories @file{$HOME/.ffmpeg}, @file{/usr/local/share/ffmpeg} and
804 @file{/usr/share/ffmpeg} in that order. For example, if the argument
805 is @code{libx264-max}, it will search for the file
806 @file{libx264-max.ffpreset}.
808 If no such file is found, then ffmpeg will search for a file named
809 @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
810 directories, where @var{codec_name} is the name of the codec to which
811 the preset file options will be applied. For example, if you select
812 the video codec with @code{-vcodec libx264} and use @code{-vpre max},
813 then it will search for the file @file{libx264-max.ffpreset}.
815 Finally, if the above rules failed and the argument specifies an
816 absolute pathname, ffmpeg will search for that filename. This way you
817 can specify the absolute and complete filename of the preset file, for
818 example @file{./ffpresets/libx264-max.ffpreset}.
820 @node FFmpeg formula evaluator
821 @section FFmpeg formula evaluator
823 When evaluating a rate control string, FFmpeg uses an internal formula
826 The following binary operators are available: @code{+}, @code{-},
827 @code{*}, @code{/}, @code{^}.
829 The following unary operators are available: @code{+}, @code{-},
832 The following functions are available:
854 The following constants are available:
883 @settitle FFmpeg video converter
886 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
897 The file name can be @file{-} to read from standard input or to write
900 FFmpeg also handles many protocols specified with an URL syntax.
902 Use 'ffmpeg -formats' to see a list of the supported protocols.
904 The protocol @code{http:} is currently used only to communicate with
905 FFserver (see the FFserver documentation). When FFmpeg will be a
906 video player it will also be used for streaming :-)
911 @item For streaming at very low bitrate application, use a low frame rate
912 and a small GOP size. This is especially true for RealVideo where
913 the Linux player does not seem to be very fast, so it can miss
914 frames. An example is:
917 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
920 @item The parameter 'q' which is displayed while encoding is the current
921 quantizer. The value 1 indicates that a very good quality could
922 be achieved. The value 31 indicates the worst quality. If q=31 appears
923 too often, it means that the encoder cannot compress enough to meet
924 your bitrate. You must either increase the bitrate, decrease the
925 frame rate or decrease the frame size.
927 @item If your computer is not fast enough, you can speed up the
928 compression at the expense of the compression ratio. You can use
929 '-me zero' to speed up motion estimation, and '-intra' to disable
930 motion estimation completely (you have only I-frames, which means it
931 is about as good as JPEG compression).
933 @item To have very low audio bitrates, reduce the sampling frequency
934 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
936 @item To have a constant quality (but a variable bitrate), use the option
937 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
940 @item When converting video files, you can use the '-sameq' option which
941 uses the same quality factor in the encoder as in the decoder.
942 It allows almost lossless encoding.