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.
240 The fields preceding the format names have the following meanings:
249 Show available codecs.
251 The fields preceding the codec names have the following meanings:
258 Video/audio/subtitle codec
260 Codec supports slices
262 Codec supports direct rendering
264 Codec can handle input truncated at random locations instead of only at frame boundaries
268 Show available bitstream filters.
271 Show available protocols.
276 @item -i @var{filename}
280 Overwrite output files.
282 @item -t @var{duration}
283 Restrict the transcoded/captured video sequence
284 to the duration specified in seconds.
285 @code{hh:mm:ss[.xxx]} syntax is also supported.
287 @item -fs @var{limit_size}
288 Set the file size limit.
290 @item -ss @var{position}
291 Seek to given time position in seconds.
292 @code{hh:mm:ss[.xxx]} syntax is also supported.
294 @item -itsoffset @var{offset}
295 Set the input time offset in seconds.
296 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
297 This option affects all the input files that follow it.
298 The offset is added to the timestamps of the input files.
299 Specifying a positive offset means that the corresponding
300 streams are delayed by 'offset' seconds.
302 @item -timestamp @var{time}
305 @item -metadata @var{key}=@var{value}
306 Set a metadata key/value pair.
308 For example, for setting the title in the output file:
310 ffmpeg -i in.avi -metadata title="my title" out.flv
313 @item -v @var{number}
314 Set the logging verbosity level.
316 @item -loglevel @var{loglevel}
317 Set the logging level used by the library.
318 @var{loglevel} is a number or a string containing one of the following values:
330 @item -target @var{type}
331 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
332 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
333 buffer sizes) are then set automatically. You can just type:
336 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
339 Nevertheless you can specify additional options as long as you know
340 they do not conflict with the standard, as in:
343 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
346 @item -dframes @var{number}
347 Set the number of data frames to record.
349 @item -scodec @var{codec}
350 Force subtitle codec ('copy' to copy stream).
353 Add a new subtitle stream to the current output stream.
355 @item -slang @var{code}
356 Set the ISO 639 language code (3 letters) of the current subtitle stream.
360 @section Video Options
363 @item -b @var{bitrate}
364 Set the video bitrate in bit/s (default = 200 kb/s).
365 @item -vframes @var{number}
366 Set the number of video frames to record.
368 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
370 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
371 The following abbreviations are recognized:
433 @item -aspect @var{aspect}
434 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
435 @item -croptop @var{size}
436 Set top crop band size (in pixels).
437 @item -cropbottom @var{size}
438 Set bottom crop band size (in pixels).
439 @item -cropleft @var{size}
440 Set left crop band size (in pixels).
441 @item -cropright @var{size}
442 Set right crop band size (in pixels).
443 @item -padtop @var{size}
444 Set top pad band size (in pixels).
445 @item -padbottom @var{size}
446 Set bottom pad band size (in pixels).
447 @item -padleft @var{size}
448 Set left pad band size (in pixels).
449 @item -padright @var{size}
450 Set right pad band size (in pixels).
451 @item -padcolor @var{hex_color}
452 Set color of padded bands. The value for padcolor is expressed
453 as a six digit hexadecimal number where the first two digits
454 represent red, the middle two digits green and last two digits
455 blue (default = 000000 (black)).
457 Disable video recording.
458 @item -bt @var{tolerance}
459 Set video bitrate tolerance (in bits, default 4000k).
460 Has a minimum value of: (target_bitrate/target_framerate).
461 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
462 willing to deviate from the target average bitrate value. This is
463 not related to min/max bitrate. Lowering tolerance too much has
464 an adverse effect on quality.
465 @item -maxrate @var{bitrate}
466 Set max video bitrate (in bit/s).
467 Requires -bufsize to be set.
468 @item -minrate @var{bitrate}
469 Set min video bitrate (in bit/s).
470 Most useful in setting up a CBR encode:
472 ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
474 It is of little use elsewise.
475 @item -bufsize @var{size}
476 Set video buffer verifier buffer size (in bits).
477 @item -vcodec @var{codec}
478 Force video codec to @var{codec}. Use the @code{copy} special value to
479 tell that the raw codec data must be copied as is.
481 Use same video quality as source (implies VBR).
484 Select the pass number (1 or 2). It is used to do two-pass
485 video encoding. The statistics of the video are recorded in the first
486 pass into a log file (see also the option -passlogfile),
487 and in the second pass that log file is used to generate the video
488 at the exact requested bitrate.
489 On pass 1, you may just deactivate audio and set output to null,
490 examples for Windows and Unix:
492 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
493 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
496 @item -passlogfile @var{prefix}
497 Set two-pass log file name prefix to @var{prefix}, the default file name
498 prefix is ``ffmpeg2pass''. The complete file name will be
499 @file{PREFIX-N.log}, where N is a number specific to the output
503 Add a new video stream to the current output stream.
507 @section Advanced Video Options
510 @item -pix_fmt @var{format}
511 Set pixel format. Use 'list' as parameter to show all the supported
513 @item -sws_flags @var{flags}
514 Set SwScaler flags (only available when compiled with swscale support).
515 @item -g @var{gop_size}
516 Set the group of pictures size.
518 Use only intra frames.
521 @item -qscale @var{q}
522 Use fixed video quantizer scale (VBR).
524 minimum video quantizer scale (VBR)
526 maximum video quantizer scale (VBR)
528 maximum difference between the quantizer scales (VBR)
529 @item -qblur @var{blur}
530 video quantizer scale blur (VBR) (range 0.0 - 1.0)
531 @item -qcomp @var{compression}
532 video quantizer scale compression (VBR) (default 0.5).
533 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
535 @item -lmin @var{lambda}
536 minimum video lagrange factor (VBR)
537 @item -lmax @var{lambda}
538 max video lagrange factor (VBR)
539 @item -mblmin @var{lambda}
540 minimum macroblock quantizer scale (VBR)
541 @item -mblmax @var{lambda}
542 maximum macroblock quantizer scale (VBR)
544 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
545 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
547 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
550 @item -rc_init_cplx @var{complexity}
551 initial complexity for single pass encoding
552 @item -b_qfactor @var{factor}
553 qp factor between P- and B-frames
554 @item -i_qfactor @var{factor}
555 qp factor between P- and I-frames
556 @item -b_qoffset @var{offset}
557 qp offset between P- and B-frames
558 @item -i_qoffset @var{offset}
559 qp offset between P- and I-frames
560 @item -rc_eq @var{equation}
561 Set rate control equation (@pxref{FFmpeg formula
562 evaluator}) (default = @code{tex^qComp}).
563 @item -rc_override @var{override}
564 rate control override for specific intervals
565 @item -me_method @var{method}
566 Set motion estimation method to @var{method}.
567 Available methods are (from lowest to best quality):
570 Try just the (0, 0) vector.
579 exhaustive search (slow and marginally better than epzs)
582 @item -dct_algo @var{algo}
583 Set DCT algorithm to @var{algo}. Available values are:
586 FF_DCT_AUTO (default)
599 @item -idct_algo @var{algo}
600 Set IDCT algorithm to @var{algo}. Available values are:
603 FF_IDCT_AUTO (default)
627 Set error resilience to @var{n}.
630 FF_ER_CAREFUL (default)
636 FF_ER_VERY_AGGRESSIVE
639 @item -ec @var{bit_mask}
640 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
641 the following values:
644 FF_EC_GUESS_MVS (default = enabled)
646 FF_EC_DEBLOCK (default = enabled)
649 @item -bf @var{frames}
650 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
651 @item -mbd @var{mode}
655 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
657 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
659 FF_MB_DECISION_RD: rate distortion
663 Use four motion vector by macroblock (MPEG-4 only).
665 Use data partitioning (MPEG-4 only).
666 @item -bug @var{param}
667 Work around encoder bugs that are not auto-detected.
668 @item -strict @var{strictness}
669 How strictly to follow the standards.
671 Enable Advanced intra coding (h263+).
673 Enable Unlimited Motion Vector (h263+)
676 Deinterlace pictures.
678 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
679 Use this option if your input file is interlaced and you want
680 to keep the interlaced format for minimum losses.
681 The alternative is to deinterlace the input stream with
682 @option{-deinterlace}, but deinterlacing introduces losses.
684 Calculate PSNR of compressed frames.
686 Dump video coding statistics to @file{vstats_HHMMSS.log}.
687 @item -vstats_file @var{file}
688 Dump video coding statistics to @var{file}.
690 top=1/bottom=0/auto=-1 field first
691 @item -dc @var{precision}
693 @item -vtag @var{fourcc/tag}
694 Force video tag/fourcc.
697 @item -vbsf @var{bitstream_filter}
698 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
700 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
704 @section Audio Options
707 @item -aframes @var{number}
708 Set the number of audio frames to record.
710 Set the audio sampling frequency (default = 44100 Hz).
711 @item -ab @var{bitrate}
712 Set the audio bitrate in bit/s (default = 64k).
713 @item -ac @var{channels}
714 Set the number of audio channels (default = 1).
716 Disable audio recording.
717 @item -acodec @var{codec}
718 Force audio codec to @var{codec}. Use the @code{copy} special value to
719 specify that the raw codec data must be copied as is.
721 Add a new audio track to the output file. If you want to specify parameters,
722 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
724 Mapping will be done automatically, if the number of output streams is equal to
725 the number of input streams, else it will pick the first one that matches. You
726 can override the mapping using @code{-map} as usual.
730 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
732 @item -alang @var{code}
733 Set the ISO 639 language code (3 letters) of the current audio stream.
736 @section Advanced Audio options:
739 @item -atag @var{fourcc/tag}
740 Force audio tag/fourcc.
741 @item -absf @var{bitstream_filter}
742 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
745 @section Subtitle options:
748 @item -scodec @var{codec}
749 Force subtitle codec ('copy' to copy stream).
751 Add a new subtitle stream to the current output stream.
752 @item -slang @var{code}
753 Set the ISO 639 language code (3 letters) of the current subtitle stream.
755 Disable subtitle recording.
756 @item -sbsf @var{bitstream_filter}
757 Bitstream filters available are "mov2textsub", "text2movsub".
759 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
763 @section Audio/Video grab options
766 @item -vc @var{channel}
767 Set video grab channel (DV1394 only).
768 @item -tvstd @var{standard}
769 Set television standard (NTSC, PAL (SECAM)).
771 Synchronize read on input.
774 @section Advanced options
777 @item -map @var{input_stream_id}[:@var{sync_stream_id}]
778 Set stream mapping from input streams to output streams.
779 Just enumerate the input streams in the order you want them in the output.
780 @var{sync_stream_id} if specified sets the input stream to sync
782 @item -map_meta_data @var{outfile}:@var{infile}
783 Set meta data information of @var{outfile} from @var{infile}.
785 Print specific debug info.
787 Add timings for benchmarking.
789 Dump each input packet.
791 When dumping packets, also dump the payload.
793 Only use bit exact algorithms (for codec testing).
795 Set RTP payload size in bytes.
797 Read input at native frame rate. Mainly used to simulate a grab device.
799 Loop over the input stream. Currently it works only for image
800 streams. This option is used for automatic FFserver testing.
801 @item -loop_output @var{number_of_times}
802 Repeatedly loop output for formats that support looping such as animated GIF
803 (0 will loop the output infinitely).
804 @item -threads @var{count}
806 @item -vsync @var{parameter}
807 Video sync method. Video will be stretched/squeezed to match the timestamps,
808 it is done by duplicating and dropping frames. With -map you can select from
809 which stream the timestamps should be taken. You can leave either video or
810 audio unchanged and sync the remaining stream(s) to the unchanged one.
811 @item -async @var{samples_per_second}
812 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
813 the parameter is the maximum samples per second by which the audio is changed.
814 -async 1 is a special case where only the start of the audio stream is corrected
815 without any later correction.
817 Copy timestamps from input to output.
819 Finish encoding when the shortest input stream ends.
820 @item -dts_delta_threshold
821 Timestamp discontinuity delta threshold.
822 @item -muxdelay @var{seconds}
823 Set the maximum demux-decode delay.
824 @item -muxpreload @var{seconds}
825 Set the initial demux-decode delay.
828 @section Preset files
830 A preset file contains a sequence of @var{option}=@var{value} pairs,
831 one for each line, specifying a sequence of options which would be
832 awkward to specify on the command line. Lines starting with the hash
833 ('#') character are ignored and are used to provide comments. Check
834 the @file{ffpresets} directory in the FFmpeg source tree for examples.
836 Preset files are specified with the @code{vpre}, @code{apre} and
837 @code{spre} options. The options specified in a preset file are
838 applied to the currently selected codec of the same type as the preset
841 The argument passed to the preset options identifies the preset file
842 to use according to the following rules.
844 First ffmpeg searches for a file named @var{arg}.ffpreset in the
845 directories @file{$HOME/.ffmpeg}, and in the datadir defined at
846 configuration time (usually @file{PREFIX/share/ffmpeg}) in that
847 order. For example, if the argument is @code{libx264-max}, it will
848 search for the file @file{libx264-max.ffpreset}.
850 If no such file is found, then ffmpeg will search for a file named
851 @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
852 directories, where @var{codec_name} is the name of the codec to which
853 the preset file options will be applied. For example, if you select
854 the video codec with @code{-vcodec libx264} and use @code{-vpre max},
855 then it will search for the file @file{libx264-max.ffpreset}.
857 Finally, if the above rules failed and the argument specifies an
858 absolute pathname, ffmpeg will search for that filename. This way you
859 can specify the absolute and complete filename of the preset file, for
860 example @file{./ffpresets/libx264-max.ffpreset}.
862 @anchor{FFmpeg formula evaluator}
863 @section FFmpeg formula evaluator
865 When evaluating a rate control string, FFmpeg uses an internal formula
868 The following binary operators are available: @code{+}, @code{-},
869 @code{*}, @code{/}, @code{^}.
871 The following unary operators are available: @code{+}, @code{-},
874 The following statements are available: @code{ld}, @code{st},
877 The following functions are available:
905 The following constants are available:
934 @settitle FFmpeg video converter
937 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
948 The file name can be @file{-} to read from standard input or to write
951 FFmpeg also handles many protocols specified with an URL syntax.
953 Use 'ffmpeg -protocols' to see a list of the supported protocols.
955 The protocol @code{http:} is currently used only to communicate with
956 FFserver (see the FFserver documentation). When FFmpeg will be a
957 video player it will also be used for streaming :-)
962 @item For streaming at very low bitrate application, use a low frame rate
963 and a small GOP size. This is especially true for RealVideo where
964 the Linux player does not seem to be very fast, so it can miss
965 frames. An example is:
968 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
971 @item The parameter 'q' which is displayed while encoding is the current
972 quantizer. The value 1 indicates that a very good quality could
973 be achieved. The value 31 indicates the worst quality. If q=31 appears
974 too often, it means that the encoder cannot compress enough to meet
975 your bitrate. You must either increase the bitrate, decrease the
976 frame rate or decrease the frame size.
978 @item If your computer is not fast enough, you can speed up the
979 compression at the expense of the compression ratio. You can use
980 '-me zero' to speed up motion estimation, and '-intra' to disable
981 motion estimation completely (you have only I-frames, which means it
982 is about as good as JPEG compression).
984 @item To have very low audio bitrates, reduce the sampling frequency
985 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
987 @item To have a constant quality (but a variable bitrate), use the option
988 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
991 @item When converting video files, you can use the '-sameq' option which
992 uses the same quality factor in the encoder as in the decoder.
993 It allows almost lossless encoding.