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
228 @include fftools-common-opts.texi
233 @item -i @var{filename}
237 Overwrite output files.
239 @item -t @var{duration}
240 Restrict the transcoded/captured video sequence
241 to the duration specified in seconds.
242 @code{hh:mm:ss[.xxx]} syntax is also supported.
244 @item -fs @var{limit_size}
245 Set the file size limit.
247 @item -ss @var{position}
248 Seek to given time position in seconds.
249 @code{hh:mm:ss[.xxx]} syntax is also supported.
251 @item -itsoffset @var{offset}
252 Set the input time offset in seconds.
253 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
254 This option affects all the input files that follow it.
255 The offset is added to the timestamps of the input files.
256 Specifying a positive offset means that the corresponding
257 streams are delayed by 'offset' seconds.
259 @item -timestamp @var{time}
262 @item -metadata @var{key}=@var{value}
263 Set a metadata key/value pair.
265 For example, for setting the title in the output file:
267 ffmpeg -i in.avi -metadata title="my title" out.flv
270 @item -v @var{number}
271 Set the logging verbosity level.
273 @item -target @var{type}
274 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
275 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
276 buffer sizes) are then set automatically. You can just type:
279 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
282 Nevertheless you can specify additional options as long as you know
283 they do not conflict with the standard, as in:
286 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
289 @item -dframes @var{number}
290 Set the number of data frames to record.
292 @item -scodec @var{codec}
293 Force subtitle codec ('copy' to copy stream).
296 Add a new subtitle stream to the current output stream.
298 @item -slang @var{code}
299 Set the ISO 639 language code (3 letters) of the current subtitle stream.
303 @section Video Options
306 @item -b @var{bitrate}
307 Set the video bitrate in bit/s (default = 200 kb/s).
308 @item -vframes @var{number}
309 Set the number of video frames to record.
311 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
313 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
314 The following abbreviations are recognized:
376 @item -aspect @var{aspect}
377 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
378 @item -croptop @var{size}
379 Set top crop band size (in pixels).
380 @item -cropbottom @var{size}
381 Set bottom crop band size (in pixels).
382 @item -cropleft @var{size}
383 Set left crop band size (in pixels).
384 @item -cropright @var{size}
385 Set right crop band size (in pixels).
386 @item -padtop @var{size}
387 Set top pad band size (in pixels).
388 @item -padbottom @var{size}
389 Set bottom pad band size (in pixels).
390 @item -padleft @var{size}
391 Set left pad band size (in pixels).
392 @item -padright @var{size}
393 Set right pad band size (in pixels).
394 @item -padcolor @var{hex_color}
395 Set color of padded bands. The value for padcolor is expressed
396 as a six digit hexadecimal number where the first two digits
397 represent red, the middle two digits green and last two digits
398 blue (default = 000000 (black)).
400 Disable video recording.
401 @item -bt @var{tolerance}
402 Set video bitrate tolerance (in bits, default 4000k).
403 Has a minimum value of: (target_bitrate/target_framerate).
404 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
405 willing to deviate from the target average bitrate value. This is
406 not related to min/max bitrate. Lowering tolerance too much has
407 an adverse effect on quality.
408 @item -maxrate @var{bitrate}
409 Set max video bitrate (in bit/s).
410 Requires -bufsize to be set.
411 @item -minrate @var{bitrate}
412 Set min video bitrate (in bit/s).
413 Most useful in setting up a CBR encode:
415 ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
417 It is of little use elsewise.
418 @item -bufsize @var{size}
419 Set video buffer verifier buffer size (in bits).
420 @item -vcodec @var{codec}
421 Force video codec to @var{codec}. Use the @code{copy} special value to
422 tell that the raw codec data must be copied as is.
424 Use same video quality as source (implies VBR).
427 Select the pass number (1 or 2). It is used to do two-pass
428 video encoding. The statistics of the video are recorded in the first
429 pass into a log file (see also the option -passlogfile),
430 and in the second pass that log file is used to generate the video
431 at the exact requested bitrate.
432 On pass 1, you may just deactivate audio and set output to null,
433 examples for Windows and Unix:
435 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
436 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
439 @item -passlogfile @var{prefix}
440 Set two-pass log file name prefix to @var{prefix}, the default file name
441 prefix is ``ffmpeg2pass''. The complete file name will be
442 @file{PREFIX-N.log}, where N is a number specific to the output
446 Add a new video stream to the current output stream.
448 @item -vlang @var{code}
449 Set the ISO 639 language code (3 letters) of the current video stream.
453 @section Advanced Video Options
456 @item -pix_fmt @var{format}
457 Set pixel format. Use 'list' as parameter to show all the supported
459 @item -sws_flags @var{flags}
460 Set SwScaler flags (only available when compiled with swscale support).
461 @item -g @var{gop_size}
462 Set the group of pictures size.
464 Use only intra frames.
467 @item -qscale @var{q}
468 Use fixed video quantizer scale (VBR).
470 minimum video quantizer scale (VBR)
472 maximum video quantizer scale (VBR)
474 maximum difference between the quantizer scales (VBR)
475 @item -qblur @var{blur}
476 video quantizer scale blur (VBR) (range 0.0 - 1.0)
477 @item -qcomp @var{compression}
478 video quantizer scale compression (VBR) (default 0.5).
479 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
481 @item -lmin @var{lambda}
482 minimum video lagrange factor (VBR)
483 @item -lmax @var{lambda}
484 max video lagrange factor (VBR)
485 @item -mblmin @var{lambda}
486 minimum macroblock quantizer scale (VBR)
487 @item -mblmax @var{lambda}
488 maximum macroblock quantizer scale (VBR)
490 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
491 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
493 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
496 @item -rc_init_cplx @var{complexity}
497 initial complexity for single pass encoding
498 @item -b_qfactor @var{factor}
499 qp factor between P- and B-frames
500 @item -i_qfactor @var{factor}
501 qp factor between P- and I-frames
502 @item -b_qoffset @var{offset}
503 qp offset between P- and B-frames
504 @item -i_qoffset @var{offset}
505 qp offset between P- and I-frames
506 @item -rc_eq @var{equation}
507 Set rate control equation (@pxref{FFmpeg formula
508 evaluator}) (default = @code{tex^qComp}).
509 @item -rc_override @var{override}
510 rate control override for specific intervals
511 @item -me_method @var{method}
512 Set motion estimation method to @var{method}.
513 Available methods are (from lowest to best quality):
516 Try just the (0, 0) vector.
525 exhaustive search (slow and marginally better than epzs)
528 @item -dct_algo @var{algo}
529 Set DCT algorithm to @var{algo}. Available values are:
532 FF_DCT_AUTO (default)
545 @item -idct_algo @var{algo}
546 Set IDCT algorithm to @var{algo}. Available values are:
549 FF_IDCT_AUTO (default)
573 Set error resilience to @var{n}.
576 FF_ER_CAREFUL (default)
582 FF_ER_VERY_AGGRESSIVE
585 @item -ec @var{bit_mask}
586 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
587 the following values:
590 FF_EC_GUESS_MVS (default = enabled)
592 FF_EC_DEBLOCK (default = enabled)
595 @item -bf @var{frames}
596 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
597 @item -mbd @var{mode}
601 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
603 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
605 FF_MB_DECISION_RD: rate distortion
609 Use four motion vector by macroblock (MPEG-4 only).
611 Use data partitioning (MPEG-4 only).
612 @item -bug @var{param}
613 Work around encoder bugs that are not auto-detected.
614 @item -strict @var{strictness}
615 How strictly to follow the standards.
617 Enable Advanced intra coding (h263+).
619 Enable Unlimited Motion Vector (h263+)
622 Deinterlace pictures.
624 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
625 Use this option if your input file is interlaced and you want
626 to keep the interlaced format for minimum losses.
627 The alternative is to deinterlace the input stream with
628 @option{-deinterlace}, but deinterlacing introduces losses.
630 Calculate PSNR of compressed frames.
632 Dump video coding statistics to @file{vstats_HHMMSS.log}.
633 @item -vstats_file @var{file}
634 Dump video coding statistics to @var{file}.
636 top=1/bottom=0/auto=-1 field first
637 @item -dc @var{precision}
639 @item -vtag @var{fourcc/tag}
640 Force video tag/fourcc.
643 @item -vbsf @var{bitstream_filter}
644 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
646 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
650 @section Audio Options
653 @item -aframes @var{number}
654 Set the number of audio frames to record.
656 Set the audio sampling frequency (default = 44100 Hz).
657 @item -ab @var{bitrate}
658 Set the audio bitrate in bit/s (default = 64k).
659 @item -ac @var{channels}
660 Set the number of audio channels (default = 1).
662 Disable audio recording.
663 @item -acodec @var{codec}
664 Force audio codec to @var{codec}. Use the @code{copy} special value to
665 specify that the raw codec data must be copied as is.
667 Add a new audio track to the output file. If you want to specify parameters,
668 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
670 Mapping will be done automatically, if the number of output streams is equal to
671 the number of input streams, else it will pick the first one that matches. You
672 can override the mapping using @code{-map} as usual.
676 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
678 @item -alang @var{code}
679 Set the ISO 639 language code (3 letters) of the current audio stream.
682 @section Advanced Audio options:
685 @item -atag @var{fourcc/tag}
686 Force audio tag/fourcc.
687 @item -absf @var{bitstream_filter}
688 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
691 @section Subtitle options:
694 @item -scodec @var{codec}
695 Force subtitle codec ('copy' to copy stream).
697 Add a new subtitle stream to the current output stream.
698 @item -slang @var{code}
699 Set the ISO 639 language code (3 letters) of the current subtitle stream.
701 Disable subtitle recording.
702 @item -sbsf @var{bitstream_filter}
703 Bitstream filters available are "mov2textsub", "text2movsub".
705 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
709 @section Audio/Video grab options
712 @item -vc @var{channel}
713 Set video grab channel (DV1394 only).
714 @item -tvstd @var{standard}
715 Set television standard (NTSC, PAL (SECAM)).
717 Synchronize read on input.
720 @section Advanced options
723 @item -map @var{input_stream_id}[:@var{sync_stream_id}]
724 Set stream mapping from input streams to output streams.
725 Just enumerate the input streams in the order you want them in the output.
726 @var{sync_stream_id} if specified sets the input stream to sync
728 @item -map_meta_data @var{outfile}:@var{infile}
729 Set meta data information of @var{outfile} from @var{infile}.
731 Print specific debug info.
733 Add timings for benchmarking.
735 Dump each input packet.
737 When dumping packets, also dump the payload.
739 Only use bit exact algorithms (for codec testing).
741 Set RTP payload size in bytes.
743 Read input at native frame rate. Mainly used to simulate a grab device.
745 Loop over the input stream. Currently it works only for image
746 streams. This option is used for automatic FFserver testing.
747 @item -loop_output @var{number_of_times}
748 Repeatedly loop output for formats that support looping such as animated GIF
749 (0 will loop the output infinitely).
750 @item -threads @var{count}
752 @item -vsync @var{parameter}
753 Video sync method. Video will be stretched/squeezed to match the timestamps,
754 it is done by duplicating and dropping frames. With -map you can select from
755 which stream the timestamps should be taken. You can leave either video or
756 audio unchanged and sync the remaining stream(s) to the unchanged one.
757 @item -async @var{samples_per_second}
758 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
759 the parameter is the maximum samples per second by which the audio is changed.
760 -async 1 is a special case where only the start of the audio stream is corrected
761 without any later correction.
763 Copy timestamps from input to output.
765 Finish encoding when the shortest input stream ends.
766 @item -dts_delta_threshold
767 Timestamp discontinuity delta threshold.
768 @item -muxdelay @var{seconds}
769 Set the maximum demux-decode delay.
770 @item -muxpreload @var{seconds}
771 Set the initial demux-decode delay.
774 @section Preset files
776 A preset file contains a sequence of @var{option}=@var{value} pairs,
777 one for each line, specifying a sequence of options which would be
778 awkward to specify on the command line. Lines starting with the hash
779 ('#') character are ignored and are used to provide comments. Check
780 the @file{ffpresets} directory in the FFmpeg source tree for examples.
782 Preset files are specified with the @code{vpre}, @code{apre},
783 @code{spre}, and @code{fpre} options. The @code{fpre} option takes the
784 filename of the preset instead of a preset name as input and can be
785 used for any kind of codec. For the @code{vpre}, @code{apre}, and
786 @code{spre} options, the options specified in a preset file are
787 applied to the currently selected codec of the same type as the preset
790 The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
791 preset options identifies the preset file to use according to the
794 First ffmpeg searches for a file named @var{arg}.ffpreset in the
795 directories @file{$HOME/.ffmpeg}, and in the datadir defined at
796 configuration time (usually @file{PREFIX/share/ffmpeg}) in that
797 order. For example, if the argument is @code{libx264-max}, it will
798 search for the file @file{libx264-max.ffpreset}.
800 If no such file is found, then ffmpeg will search for a file named
801 @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
802 directories, where @var{codec_name} is the name of the codec to which
803 the preset file options will be applied. For example, if you select
804 the video codec with @code{-vcodec libx264} and use @code{-vpre max},
805 then it will search for the file @file{libx264-max.ffpreset}.
807 @anchor{FFmpeg formula evaluator}
808 @section FFmpeg formula evaluator
810 When evaluating a rate control string, FFmpeg uses an internal formula
813 The following binary operators are available: @code{+}, @code{-},
814 @code{*}, @code{/}, @code{^}.
816 The following unary operators are available: @code{+}, @code{-},
819 The following statements are available: @code{ld}, @code{st},
822 The following functions are available:
850 The following constants are available:
879 @settitle FFmpeg video converter
882 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
893 The file name can be @file{-} to read from standard input or to write
896 FFmpeg also handles many protocols specified with an URL syntax.
898 Use 'ffmpeg -protocols' to see a list of the supported protocols.
900 The protocol @code{http:} is currently used only to communicate with
901 FFserver (see the FFserver documentation). When FFmpeg will be a
902 video player it will also be used for streaming :-)
907 @item For streaming at very low bitrate application, use a low frame rate
908 and a small GOP size. This is especially true for RealVideo where
909 the Linux player does not seem to be very fast, so it can miss
910 frames. An example is:
913 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
916 @item The parameter 'q' which is displayed while encoding is the current
917 quantizer. The value 1 indicates that a very good quality could
918 be achieved. The value 31 indicates the worst quality. If q=31 appears
919 too often, it means that the encoder cannot compress enough to meet
920 your bitrate. You must either increase the bitrate, decrease the
921 frame rate or decrease the frame size.
923 @item If your computer is not fast enough, you can speed up the
924 compression at the expense of the compression ratio. You can use
925 '-me zero' to speed up motion estimation, and '-intra' to disable
926 motion estimation completely (you have only I-frames, which means it
927 is about as good as JPEG compression).
929 @item To have very low audio bitrates, reduce the sampling frequency
930 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
932 @item To have a constant quality (but a variable bitrate), use the option
933 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
936 @item When converting video files, you can use the '-sameq' option which
937 uses the same quality factor in the encoder as in the decoder.
938 It allows almost lossless encoding.