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 22050Hz 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}.
149 The generic syntax is:
152 @c man begin SYNOPSIS
153 ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
156 @c man begin DESCRIPTION
157 As a general rule, options are applied to the next specified
158 file. Therefore, order is important, and you can have the same
159 option on the command line multiple times. Each occurrence is
160 then applied to the next input or output file.
162 * To set the video bitrate of the output file to 64kbit/s:
164 ffmpeg -i input.avi -b 64k output.avi
167 * To force the frame rate of the output file to 24 fps:
169 ffmpeg -i input.avi -r 24 output.avi
172 * To force the frame rate of the input file (valid for raw formats only)
173 to 1 fps and the frame rate of the output file to 24 fps:
175 ffmpeg -r 1 -i input.m2v -r 24 output.avi
178 The format option may be needed for raw input files.
180 By default, FFmpeg tries to convert as losslessly as possible: It
181 uses the same audio and video parameters for the outputs as the one
182 specified for the inputs.
186 @section Main options
199 Show available formats, codecs, protocols, ...
204 @item -i @var{filename}
208 Overwrite output files.
210 @item -t @var{duration}
211 Restrict the transcoded/captured video sequence
212 to the duration specified in seconds.
213 @code{hh:mm:ss[.xxx]} syntax is also supported.
215 @item -fs @var{limit_size}
216 Set the file size limit.
218 @item -ss @var{position}
219 Seek to given time position in seconds.
220 @code{hh:mm:ss[.xxx]} syntax is also supported.
222 @item -itsoffset @var{offset}
223 Set the input time offset in seconds.
224 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
225 This option affects all the input files that follow it.
226 The offset is added to the timestamps of the input files.
227 Specifying a positive offset means that the corresponding
228 streams are delayed by 'offset' seconds.
230 @item -title @var{string}
233 @item -timestamp @var{time}
236 @item -author @var{string}
239 @item -copyright @var{string}
242 @item -comment @var{string}
245 @item -album @var{string}
248 @item -track @var{number}
251 @item -year @var{number}
254 @item -v @var{number}
255 Set the logging verbosity level.
257 @item -target @var{type}
258 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
259 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
260 buffer sizes) are then set automatically. You can just type:
263 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
266 Nevertheless you can specify additional options as long as you know
267 they do not conflict with the standard, as in:
270 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
273 @item -dframes @var{number}
274 Set the number of data frames to record.
276 @item -scodec @var{codec}
277 Force subtitle codec ('copy' to copy stream).
280 Add a new subtitle stream to the current output stream.
282 @item -slang @var{code}
283 Set the ISO 639 language code (3 letters) of the current subtitle stream.
287 @section Video Options
290 @item -b @var{bitrate}
291 Set the video bitrate in bit/s (default = 200 kb/s).
292 @item -vframes @var{number}
293 Set the number of video frames to record.
295 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
297 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
298 The following abbreviations are recognized:
358 @item -aspect @var{aspect}
359 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
360 @item -croptop @var{size}
361 Set top crop band size (in pixels).
362 @item -cropbottom @var{size}
363 Set bottom crop band size (in pixels).
364 @item -cropleft @var{size}
365 Set left crop band size (in pixels).
366 @item -cropright @var{size}
367 Set right crop band size (in pixels).
368 @item -padtop @var{size}
369 Set top pad band size (in pixels).
370 @item -padbottom @var{size}
371 Set bottom pad band size (in pixels).
372 @item -padleft @var{size}
373 Set left pad band size (in pixels).
374 @item -padright @var{size}
375 Set right pad band size (in pixels).
376 @item -padcolor @var{hex_color}
377 Set color of padded bands. The value for padcolor is expressed
378 as a six digit hexadecimal number where the first two digits
379 represent red, the middle two digits green and last two digits
380 blue (default = 000000 (black)).
382 Disable video recording.
383 @item -bt @var{tolerance}
384 Set video bitrate tolerance (in bits, default 4000k).
385 Has a minimum value of: (target_bitrate/target_framerate).
386 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
387 willing to deviate from the target average bitrate value. This is
388 not related to min/max bitrate. Lowering tolerance too much has
389 an adverse effect on quality.
390 @item -maxrate @var{bitrate}
391 Set max video bitrate (in bit/s).
392 Requires -bufsize to be set.
393 @item -minrate @var{bitrate}
394 Set min video bitrate (in bit/s).
395 Most useful in setting up a CBR encode:
397 ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
399 It is of little use elsewise.
400 @item -bufsize @var{size}
401 Set video buffer verifier buffer size (in bits).
402 @item -vcodec @var{codec}
403 Force video codec to @var{codec}. Use the @code{copy} special value to
404 tell that the raw codec data must be copied as is.
406 Use same video quality as source (implies VBR).
409 Select the pass number (1 or 2). It is useful to do two pass
410 encoding. The statistics of the video are recorded in the first
411 pass and the video is generated at the exact requested bitrate
414 @item -passlogfile @var{file}
415 Set two pass logfile name to @var{file}.
418 Add a new video stream to the current output stream.
422 @section Advanced Video Options
425 @item -pix_fmt @var{format}
426 Set pixel format. Use 'list' as parameter to show all the supported
428 @item -sws_flags @var{flags}
429 Set SwScaler flags (only available when compiled with swscale support).
430 @item -g @var{gop_size}
431 Set the group of pictures size.
433 Use only intra frames.
436 @item -qscale @var{q}
437 Use fixed video quantizer scale (VBR).
439 minimum video quantizer scale (VBR)
441 maximum video quantizer scale (VBR)
443 maximum difference between the quantizer scales (VBR)
444 @item -qblur @var{blur}
445 video quantizer scale blur (VBR) (range 0.0 - 1.0)
446 @item -qcomp @var{compression}
447 video quantizer scale compression (VBR) (default 0.5).
448 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
450 @item -lmin @var{lambda}
451 minimum video lagrange factor (VBR)
452 @item -lmax @var{lambda}
453 max video lagrange factor (VBR)
454 @item -mblmin @var{lambda}
455 minimum macroblock quantizer scale (VBR)
456 @item -mblmax @var{lambda}
457 maximum macroblock quantizer scale (VBR)
459 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
460 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
462 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
465 @item -rc_init_cplx @var{complexity}
466 initial complexity for single pass encoding
467 @item -b_qfactor @var{factor}
468 qp factor between P- and B-frames
469 @item -i_qfactor @var{factor}
470 qp factor between P- and I-frames
471 @item -b_qoffset @var{offset}
472 qp offset between P- and B-frames
473 @item -i_qoffset @var{offset}
474 qp offset between P- and I-frames
475 @item -rc_eq @var{equation}
476 Set rate control equation (@pxref{FFmpeg formula
477 evaluator}) (default = @code{tex^qComp}).
478 @item -rc_override @var{override}
479 rate control override for specific intervals
480 @item -me_method @var{method}
481 Set motion estimation method to @var{method}.
482 Available methods are (from lowest to best quality):
485 Try just the (0, 0) vector.
494 exhaustive search (slow and marginally better than epzs)
497 @item -dct_algo @var{algo}
498 Set DCT algorithm to @var{algo}. Available values are:
501 FF_DCT_AUTO (default)
514 @item -idct_algo @var{algo}
515 Set IDCT algorithm to @var{algo}. Available values are:
518 FF_IDCT_AUTO (default)
542 Set error resilience to @var{n}.
545 FF_ER_CAREFUL (default)
551 FF_ER_VERY_AGGRESSIVE
554 @item -ec @var{bit_mask}
555 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
556 the following values:
559 FF_EC_GUESS_MVS (default = enabled)
561 FF_EC_DEBLOCK (default = enabled)
564 @item -bf @var{frames}
565 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
566 @item -mbd @var{mode}
570 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
572 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
574 FF_MB_DECISION_RD: rate distortion
578 Use four motion vector by macroblock (MPEG-4 only).
580 Use data partitioning (MPEG-4 only).
581 @item -bug @var{param}
582 Work around encoder bugs that are not auto-detected.
583 @item -strict @var{strictness}
584 How strictly to follow the standards.
586 Enable Advanced intra coding (h263+).
588 Enable Unlimited Motion Vector (h263+)
591 Deinterlace pictures.
593 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
594 Use this option if your input file is interlaced and you want
595 to keep the interlaced format for minimum losses.
596 The alternative is to deinterlace the input stream with
597 @option{-deinterlace}, but deinterlacing introduces losses.
599 Calculate PSNR of compressed frames.
601 Dump video coding statistics to @file{vstats_HHMMSS.log}.
602 @item -vstats_file @var{file}
603 Dump video coding statistics to @var{file}.
604 @item -vhook @var{module}
605 Insert video processing @var{module}. @var{module} contains the module
606 name and its parameters separated by spaces.
608 top=1/bottom=0/auto=-1 field first
609 @item -dc @var{precision}
611 @item -vtag @var{fourcc/tag}
612 Force video tag/fourcc.
615 @item -vbsf @var{bitstream_filter}
616 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
618 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
622 @section Audio Options
625 @item -aframes @var{number}
626 Set the number of audio frames to record.
628 Set the audio sampling frequency (default = 44100 Hz).
629 @item -ab @var{bitrate}
630 Set the audio bitrate in bit/s (default = 64k).
631 @item -ac @var{channels}
632 Set the number of audio channels (default = 1).
634 Disable audio recording.
635 @item -acodec @var{codec}
636 Force audio codec to @var{codec}. Use the @code{copy} special value to
637 specify that the raw codec data must be copied as is.
639 Add a new audio track to the output file. If you want to specify parameters,
640 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
642 Mapping will be done automatically, if the number of output streams is equal to
643 the number of input streams, else it will pick the first one that matches. You
644 can override the mapping using @code{-map} as usual.
648 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
650 @item -alang @var{code}
651 Set the ISO 639 language code (3 letters) of the current audio stream.
654 @section Advanced Audio options:
657 @item -atag @var{fourcc/tag}
658 Force audio tag/fourcc.
659 @item -absf @var{bitstream_filter}
660 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
663 @section Subtitle options:
666 @item -scodec @var{codec}
667 Force subtitle codec ('copy' to copy stream).
669 Add a new subtitle stream to the current output stream.
670 @item -slang @var{code}
671 Set the ISO 639 language code (3 letters) of the current subtitle stream.
672 @item -sbsf @var{bitstream_filter}
673 Bitstream filters available are "mov2textsub", "text2movsub".
675 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
679 @section Audio/Video grab options
682 @item -vc @var{channel}
683 Set video grab channel (DV1394 only).
684 @item -tvstd @var{standard}
685 Set television standard (NTSC, PAL (SECAM)).
687 Synchronize read on input.
690 @section Advanced options
693 @item -map @var{input_stream_id}[:@var{sync_stream_id}]
694 Set stream mapping from input streams to output streams.
695 Just enumerate the input streams in the order you want them in the output.
696 @var{sync_stream_id} if specified sets the input stream to sync
698 @item -map_meta_data @var{outfile}:@var{infile}
699 Set meta data information of @var{outfile} from @var{infile}.
701 Print specific debug info.
703 Add timings for benchmarking.
705 Dump each input packet.
707 When dumping packets, also dump the payload.
709 Only use bit exact algorithms (for codec testing).
711 Set packet size in bits.
713 Read input at native frame rate. Mainly used to simulate a grab device.
715 Loop over the input stream. Currently it works only for image
716 streams. This option is used for automatic FFserver testing.
717 @item -loop_output @var{number_of_times}
718 Repeatedly loop output for formats that support looping such as animated GIF
719 (0 will loop the output infinitely).
720 @item -threads @var{count}
722 @item -vsync @var{parameter}
723 Video sync method. Video will be stretched/squeezed to match the timestamps,
724 it is done by duplicating and dropping frames. With -map you can select from
725 which stream the timestamps should be taken. You can leave either video or
726 audio unchanged and sync the remaining stream(s) to the unchanged one.
727 @item -async @var{samples_per_second}
728 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
729 the parameter is the maximum samples per second by which the audio is changed.
730 -async 1 is a special case where only the start of the audio stream is corrected
731 without any later correction.
733 Copy timestamps from input to output.
735 Finish encoding when the shortest input stream ends.
736 @item -dts_delta_threshold
737 Timestamp discontinuity delta threshold.
738 @item -muxdelay @var{seconds}
739 Set the maximum demux-decode delay.
740 @item -muxpreload @var{seconds}
741 Set the initial demux-decode delay.
744 @node FFmpeg formula evaluator
745 @section FFmpeg formula evaluator
747 When evaluating a rate control string, FFmpeg uses an internal formula
750 The following binary operators are available: @code{+}, @code{-},
751 @code{*}, @code{/}, @code{^}.
753 The following unary operators are available: @code{+}, @code{-},
756 The following functions are available:
778 The following constants are available:
807 @settitle FFmpeg video converter
810 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
821 The file name can be @file{-} to read from standard input or to write
824 FFmpeg also handles many protocols specified with an URL syntax.
826 Use 'ffmpeg -formats' to see a list of the supported protocols.
828 The protocol @code{http:} is currently used only to communicate with
829 FFserver (see the FFserver documentation). When FFmpeg will be a
830 video player it will also be used for streaming :-)
835 @item For streaming at very low bitrate application, use a low frame rate
836 and a small GOP size. This is especially true for RealVideo where
837 the Linux player does not seem to be very fast, so it can miss
838 frames. An example is:
841 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
844 @item The parameter 'q' which is displayed while encoding is the current
845 quantizer. The value 1 indicates that a very good quality could
846 be achieved. The value 31 indicates the worst quality. If q=31 appears
847 too often, it means that the encoder cannot compress enough to meet
848 your bitrate. You must either increase the bitrate, decrease the
849 frame rate or decrease the frame size.
851 @item If your computer is not fast enough, you can speed up the
852 compression at the expense of the compression ratio. You can use
853 '-me zero' to speed up motion estimation, and '-intra' to disable
854 motion estimation completely (you have only I-frames, which means it
855 is about as good as JPEG compression).
857 @item To have very low audio bitrates, reduce the sampling frequency
858 (down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
860 @item To have a constant quality (but a variable bitrate), use the option
861 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
864 @item When converting video files, you can use the '-sameq' option which
865 uses the same quality factor in the encoder as in the decoder.
866 It allows almost lossless encoding.