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}.
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 useful to do two pass
443 encoding. The statistics of the video are recorded in the first
444 pass and the video is generated at the exact requested bitrate
446 On pass 1, you may just deactivate audio and set output to null,
447 examples for Windows and Unix:
449 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
450 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
453 @item -passlogfile @var{file}
454 Set two pass logfile name to @var{file}.
457 Add a new video stream to the current output stream.
461 @section Advanced Video Options
464 @item -pix_fmt @var{format}
465 Set pixel format. Use 'list' as parameter to show all the supported
467 @item -sws_flags @var{flags}
468 Set SwScaler flags (only available when compiled with swscale support).
469 @item -g @var{gop_size}
470 Set the group of pictures size.
472 Use only intra frames.
475 @item -qscale @var{q}
476 Use fixed video quantizer scale (VBR).
478 minimum video quantizer scale (VBR)
480 maximum video quantizer scale (VBR)
482 maximum difference between the quantizer scales (VBR)
483 @item -qblur @var{blur}
484 video quantizer scale blur (VBR) (range 0.0 - 1.0)
485 @item -qcomp @var{compression}
486 video quantizer scale compression (VBR) (default 0.5).
487 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
489 @item -lmin @var{lambda}
490 minimum video lagrange factor (VBR)
491 @item -lmax @var{lambda}
492 max video lagrange factor (VBR)
493 @item -mblmin @var{lambda}
494 minimum macroblock quantizer scale (VBR)
495 @item -mblmax @var{lambda}
496 maximum macroblock quantizer scale (VBR)
498 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
499 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
501 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
504 @item -rc_init_cplx @var{complexity}
505 initial complexity for single pass encoding
506 @item -b_qfactor @var{factor}
507 qp factor between P- and B-frames
508 @item -i_qfactor @var{factor}
509 qp factor between P- and I-frames
510 @item -b_qoffset @var{offset}
511 qp offset between P- and B-frames
512 @item -i_qoffset @var{offset}
513 qp offset between P- and I-frames
514 @item -rc_eq @var{equation}
515 Set rate control equation (@pxref{FFmpeg formula
516 evaluator}) (default = @code{tex^qComp}).
517 @item -rc_override @var{override}
518 rate control override for specific intervals
519 @item -me_method @var{method}
520 Set motion estimation method to @var{method}.
521 Available methods are (from lowest to best quality):
524 Try just the (0, 0) vector.
533 exhaustive search (slow and marginally better than epzs)
536 @item -dct_algo @var{algo}
537 Set DCT algorithm to @var{algo}. Available values are:
540 FF_DCT_AUTO (default)
553 @item -idct_algo @var{algo}
554 Set IDCT algorithm to @var{algo}. Available values are:
557 FF_IDCT_AUTO (default)
581 Set error resilience to @var{n}.
584 FF_ER_CAREFUL (default)
590 FF_ER_VERY_AGGRESSIVE
593 @item -ec @var{bit_mask}
594 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
595 the following values:
598 FF_EC_GUESS_MVS (default = enabled)
600 FF_EC_DEBLOCK (default = enabled)
603 @item -bf @var{frames}
604 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
605 @item -mbd @var{mode}
609 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
611 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
613 FF_MB_DECISION_RD: rate distortion
617 Use four motion vector by macroblock (MPEG-4 only).
619 Use data partitioning (MPEG-4 only).
620 @item -bug @var{param}
621 Work around encoder bugs that are not auto-detected.
622 @item -strict @var{strictness}
623 How strictly to follow the standards.
625 Enable Advanced intra coding (h263+).
627 Enable Unlimited Motion Vector (h263+)
630 Deinterlace pictures.
632 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
633 Use this option if your input file is interlaced and you want
634 to keep the interlaced format for minimum losses.
635 The alternative is to deinterlace the input stream with
636 @option{-deinterlace}, but deinterlacing introduces losses.
638 Calculate PSNR of compressed frames.
640 Dump video coding statistics to @file{vstats_HHMMSS.log}.
641 @item -vstats_file @var{file}
642 Dump video coding statistics to @var{file}.
643 @item -vhook @var{module}
644 Insert video processing @var{module}. @var{module} contains the module
645 name and its parameters separated by spaces.
647 top=1/bottom=0/auto=-1 field first
648 @item -dc @var{precision}
650 @item -vtag @var{fourcc/tag}
651 Force video tag/fourcc.
654 @item -vbsf @var{bitstream_filter}
655 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
657 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
661 @section Audio Options
664 @item -aframes @var{number}
665 Set the number of audio frames to record.
667 Set the audio sampling frequency (default = 44100 Hz).
668 @item -ab @var{bitrate}
669 Set the audio bitrate in bit/s (default = 64k).
670 @item -ac @var{channels}
671 Set the number of audio channels (default = 1).
673 Disable audio recording.
674 @item -acodec @var{codec}
675 Force audio codec to @var{codec}. Use the @code{copy} special value to
676 specify that the raw codec data must be copied as is.
678 Add a new audio track to the output file. If you want to specify parameters,
679 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
681 Mapping will be done automatically, if the number of output streams is equal to
682 the number of input streams, else it will pick the first one that matches. You
683 can override the mapping using @code{-map} as usual.
687 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
689 @item -alang @var{code}
690 Set the ISO 639 language code (3 letters) of the current audio stream.
693 @section Advanced Audio options:
696 @item -atag @var{fourcc/tag}
697 Force audio tag/fourcc.
698 @item -absf @var{bitstream_filter}
699 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
702 @section Subtitle options:
705 @item -scodec @var{codec}
706 Force subtitle codec ('copy' to copy stream).
708 Add a new subtitle stream to the current output stream.
709 @item -slang @var{code}
710 Set the ISO 639 language code (3 letters) of the current subtitle stream.
711 @item -sbsf @var{bitstream_filter}
712 Bitstream filters available are "mov2textsub", "text2movsub".
714 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
718 @section Audio/Video grab options
721 @item -vc @var{channel}
722 Set video grab channel (DV1394 only).
723 @item -tvstd @var{standard}
724 Set television standard (NTSC, PAL (SECAM)).
726 Synchronize read on input.
729 @section Advanced options
732 @item -map @var{input_stream_id}[:@var{sync_stream_id}]
733 Set stream mapping from input streams to output streams.
734 Just enumerate the input streams in the order you want them in the output.
735 @var{sync_stream_id} if specified sets the input stream to sync
737 @item -map_meta_data @var{outfile}:@var{infile}
738 Set meta data information of @var{outfile} from @var{infile}.
740 Print specific debug info.
742 Add timings for benchmarking.
744 Dump each input packet.
746 When dumping packets, also dump the payload.
748 Only use bit exact algorithms (for codec testing).
750 Set packet size in bits.
752 Read input at native frame rate. Mainly used to simulate a grab device.
754 Loop over the input stream. Currently it works only for image
755 streams. This option is used for automatic FFserver testing.
756 @item -loop_output @var{number_of_times}
757 Repeatedly loop output for formats that support looping such as animated GIF
758 (0 will loop the output infinitely).
759 @item -threads @var{count}
761 @item -vsync @var{parameter}
762 Video sync method. Video will be stretched/squeezed to match the timestamps,
763 it is done by duplicating and dropping frames. With -map you can select from
764 which stream the timestamps should be taken. You can leave either video or
765 audio unchanged and sync the remaining stream(s) to the unchanged one.
766 @item -async @var{samples_per_second}
767 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
768 the parameter is the maximum samples per second by which the audio is changed.
769 -async 1 is a special case where only the start of the audio stream is corrected
770 without any later correction.
772 Copy timestamps from input to output.
774 Finish encoding when the shortest input stream ends.
775 @item -dts_delta_threshold
776 Timestamp discontinuity delta threshold.
777 @item -muxdelay @var{seconds}
778 Set the maximum demux-decode delay.
779 @item -muxpreload @var{seconds}
780 Set the initial demux-decode delay.
783 @node FFmpeg formula evaluator
784 @section FFmpeg formula evaluator
786 When evaluating a rate control string, FFmpeg uses an internal formula
789 The following binary operators are available: @code{+}, @code{-},
790 @code{*}, @code{/}, @code{^}.
792 The following unary operators are available: @code{+}, @code{-},
795 The following functions are available:
817 The following constants are available:
846 @settitle FFmpeg video converter
849 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
860 The file name can be @file{-} to read from standard input or to write
863 FFmpeg also handles many protocols specified with an URL syntax.
865 Use 'ffmpeg -formats' to see a list of the supported protocols.
867 The protocol @code{http:} is currently used only to communicate with
868 FFserver (see the FFserver documentation). When FFmpeg will be a
869 video player it will also be used for streaming :-)
874 @item For streaming at very low bitrate application, use a low frame rate
875 and a small GOP size. This is especially true for RealVideo where
876 the Linux player does not seem to be very fast, so it can miss
877 frames. An example is:
880 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
883 @item The parameter 'q' which is displayed while encoding is the current
884 quantizer. The value 1 indicates that a very good quality could
885 be achieved. The value 31 indicates the worst quality. If q=31 appears
886 too often, it means that the encoder cannot compress enough to meet
887 your bitrate. You must either increase the bitrate, decrease the
888 frame rate or decrease the frame size.
890 @item If your computer is not fast enough, you can speed up the
891 compression at the expense of the compression ratio. You can use
892 '-me zero' to speed up motion estimation, and '-intra' to disable
893 motion estimation completely (you have only I-frames, which means it
894 is about as good as JPEG compression).
896 @item To have very low audio bitrates, reduce the sampling frequency
897 (down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
899 @item To have a constant quality (but a variable bitrate), use the option
900 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
903 @item When converting video files, you can use the '-sameq' option which
904 uses the same quality factor in the encoder as in the decoder.
905 It allows almost lossless encoding.