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, codecs, bitstream filters, protocols, and frame size and frame rate abbreviations.
240 The fields preceding the format and codec names have the following meanings:
247 Video/audio/subtitle codec
249 Codec supports slices
251 Codec supports direct rendering
253 Codec can handle input truncated at random locations instead of only at frame boundaries
259 @item -i @var{filename}
263 Overwrite output files.
265 @item -t @var{duration}
266 Restrict the transcoded/captured video sequence
267 to the duration specified in seconds.
268 @code{hh:mm:ss[.xxx]} syntax is also supported.
270 @item -fs @var{limit_size}
271 Set the file size limit.
273 @item -ss @var{position}
274 Seek to given time position in seconds.
275 @code{hh:mm:ss[.xxx]} syntax is also supported.
277 @item -itsoffset @var{offset}
278 Set the input time offset in seconds.
279 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
280 This option affects all the input files that follow it.
281 The offset is added to the timestamps of the input files.
282 Specifying a positive offset means that the corresponding
283 streams are delayed by 'offset' seconds.
285 @item -timestamp @var{time}
288 @item -metadata @var{key}=@var{value}
289 Set a metadata key/par value.
292 ffmpeg -i in.avi -metadata title="my title"
295 @item -v @var{number}
296 Set the logging verbosity level.
298 @item -target @var{type}
299 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
300 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
301 buffer sizes) are then set automatically. You can just type:
304 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
307 Nevertheless you can specify additional options as long as you know
308 they do not conflict with the standard, as in:
311 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
314 @item -dframes @var{number}
315 Set the number of data frames to record.
317 @item -scodec @var{codec}
318 Force subtitle codec ('copy' to copy stream).
321 Add a new subtitle stream to the current output stream.
323 @item -slang @var{code}
324 Set the ISO 639 language code (3 letters) of the current subtitle stream.
328 @section Video Options
331 @item -b @var{bitrate}
332 Set the video bitrate in bit/s (default = 200 kb/s).
333 @item -vframes @var{number}
334 Set the number of video frames to record.
336 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
338 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
339 The following abbreviations are recognized:
401 @item -aspect @var{aspect}
402 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
403 @item -croptop @var{size}
404 Set top crop band size (in pixels).
405 @item -cropbottom @var{size}
406 Set bottom crop band size (in pixels).
407 @item -cropleft @var{size}
408 Set left crop band size (in pixels).
409 @item -cropright @var{size}
410 Set right crop band size (in pixels).
411 @item -padtop @var{size}
412 Set top pad band size (in pixels).
413 @item -padbottom @var{size}
414 Set bottom pad band size (in pixels).
415 @item -padleft @var{size}
416 Set left pad band size (in pixels).
417 @item -padright @var{size}
418 Set right pad band size (in pixels).
419 @item -padcolor @var{hex_color}
420 Set color of padded bands. The value for padcolor is expressed
421 as a six digit hexadecimal number where the first two digits
422 represent red, the middle two digits green and last two digits
423 blue (default = 000000 (black)).
425 Disable video recording.
426 @item -bt @var{tolerance}
427 Set video bitrate tolerance (in bits, default 4000k).
428 Has a minimum value of: (target_bitrate/target_framerate).
429 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
430 willing to deviate from the target average bitrate value. This is
431 not related to min/max bitrate. Lowering tolerance too much has
432 an adverse effect on quality.
433 @item -maxrate @var{bitrate}
434 Set max video bitrate (in bit/s).
435 Requires -bufsize to be set.
436 @item -minrate @var{bitrate}
437 Set min video bitrate (in bit/s).
438 Most useful in setting up a CBR encode:
440 ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
442 It is of little use elsewise.
443 @item -bufsize @var{size}
444 Set video buffer verifier buffer size (in bits).
445 @item -vcodec @var{codec}
446 Force video codec to @var{codec}. Use the @code{copy} special value to
447 tell that the raw codec data must be copied as is.
449 Use same video quality as source (implies VBR).
452 Select the pass number (1 or 2). It is used to do two-pass
453 video encoding. The statistics of the video are recorded in the first
454 pass into a log file (see also the option -passlogfile),
455 and in the second pass that log file is used to generate the video
456 at the exact requested bitrate.
457 On pass 1, you may just deactivate audio and set output to null,
458 examples for Windows and Unix:
460 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
461 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
464 @item -passlogfile @var{prefix}
465 Set two-pass log file name prefix to @var{prefix}, the default file name
466 prefix is ``ffmpeg2pass''. The complete file name will be
467 @file{PREFIX-N.log}, where N is a number specific to the output
471 Add a new video stream to the current output stream.
475 @section Advanced Video Options
478 @item -pix_fmt @var{format}
479 Set pixel format. Use 'list' as parameter to show all the supported
481 @item -sws_flags @var{flags}
482 Set SwScaler flags (only available when compiled with swscale support).
483 @item -g @var{gop_size}
484 Set the group of pictures size.
486 Use only intra frames.
489 @item -qscale @var{q}
490 Use fixed video quantizer scale (VBR).
492 minimum video quantizer scale (VBR)
494 maximum video quantizer scale (VBR)
496 maximum difference between the quantizer scales (VBR)
497 @item -qblur @var{blur}
498 video quantizer scale blur (VBR) (range 0.0 - 1.0)
499 @item -qcomp @var{compression}
500 video quantizer scale compression (VBR) (default 0.5).
501 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
503 @item -lmin @var{lambda}
504 minimum video lagrange factor (VBR)
505 @item -lmax @var{lambda}
506 max video lagrange factor (VBR)
507 @item -mblmin @var{lambda}
508 minimum macroblock quantizer scale (VBR)
509 @item -mblmax @var{lambda}
510 maximum macroblock quantizer scale (VBR)
512 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
513 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
515 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
518 @item -rc_init_cplx @var{complexity}
519 initial complexity for single pass encoding
520 @item -b_qfactor @var{factor}
521 qp factor between P- and B-frames
522 @item -i_qfactor @var{factor}
523 qp factor between P- and I-frames
524 @item -b_qoffset @var{offset}
525 qp offset between P- and B-frames
526 @item -i_qoffset @var{offset}
527 qp offset between P- and I-frames
528 @item -rc_eq @var{equation}
529 Set rate control equation (@pxref{FFmpeg formula
530 evaluator}) (default = @code{tex^qComp}).
531 @item -rc_override @var{override}
532 rate control override for specific intervals
533 @item -me_method @var{method}
534 Set motion estimation method to @var{method}.
535 Available methods are (from lowest to best quality):
538 Try just the (0, 0) vector.
547 exhaustive search (slow and marginally better than epzs)
550 @item -dct_algo @var{algo}
551 Set DCT algorithm to @var{algo}. Available values are:
554 FF_DCT_AUTO (default)
567 @item -idct_algo @var{algo}
568 Set IDCT algorithm to @var{algo}. Available values are:
571 FF_IDCT_AUTO (default)
595 Set error resilience to @var{n}.
598 FF_ER_CAREFUL (default)
604 FF_ER_VERY_AGGRESSIVE
607 @item -ec @var{bit_mask}
608 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
609 the following values:
612 FF_EC_GUESS_MVS (default = enabled)
614 FF_EC_DEBLOCK (default = enabled)
617 @item -bf @var{frames}
618 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
619 @item -mbd @var{mode}
623 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
625 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
627 FF_MB_DECISION_RD: rate distortion
631 Use four motion vector by macroblock (MPEG-4 only).
633 Use data partitioning (MPEG-4 only).
634 @item -bug @var{param}
635 Work around encoder bugs that are not auto-detected.
636 @item -strict @var{strictness}
637 How strictly to follow the standards.
639 Enable Advanced intra coding (h263+).
641 Enable Unlimited Motion Vector (h263+)
644 Deinterlace pictures.
646 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
647 Use this option if your input file is interlaced and you want
648 to keep the interlaced format for minimum losses.
649 The alternative is to deinterlace the input stream with
650 @option{-deinterlace}, but deinterlacing introduces losses.
652 Calculate PSNR of compressed frames.
654 Dump video coding statistics to @file{vstats_HHMMSS.log}.
655 @item -vstats_file @var{file}
656 Dump video coding statistics to @var{file}.
658 top=1/bottom=0/auto=-1 field first
659 @item -dc @var{precision}
661 @item -vtag @var{fourcc/tag}
662 Force video tag/fourcc.
665 @item -vbsf @var{bitstream_filter}
666 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
668 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
672 @section Audio Options
675 @item -aframes @var{number}
676 Set the number of audio frames to record.
678 Set the audio sampling frequency (default = 44100 Hz).
679 @item -ab @var{bitrate}
680 Set the audio bitrate in bit/s (default = 64k).
681 @item -ac @var{channels}
682 Set the number of audio channels (default = 1).
684 Disable audio recording.
685 @item -acodec @var{codec}
686 Force audio codec to @var{codec}. Use the @code{copy} special value to
687 specify that the raw codec data must be copied as is.
689 Add a new audio track to the output file. If you want to specify parameters,
690 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
692 Mapping will be done automatically, if the number of output streams is equal to
693 the number of input streams, else it will pick the first one that matches. You
694 can override the mapping using @code{-map} as usual.
698 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
700 @item -alang @var{code}
701 Set the ISO 639 language code (3 letters) of the current audio stream.
704 @section Advanced Audio options:
707 @item -atag @var{fourcc/tag}
708 Force audio tag/fourcc.
709 @item -absf @var{bitstream_filter}
710 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
713 @section Subtitle options:
716 @item -scodec @var{codec}
717 Force subtitle codec ('copy' to copy stream).
719 Add a new subtitle stream to the current output stream.
720 @item -slang @var{code}
721 Set the ISO 639 language code (3 letters) of the current subtitle stream.
722 @item -sbsf @var{bitstream_filter}
723 Bitstream filters available are "mov2textsub", "text2movsub".
725 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
729 @section Audio/Video grab options
732 @item -vc @var{channel}
733 Set video grab channel (DV1394 only).
734 @item -tvstd @var{standard}
735 Set television standard (NTSC, PAL (SECAM)).
737 Synchronize read on input.
740 @section Advanced options
743 @item -map @var{input_stream_id}[:@var{sync_stream_id}]
744 Set stream mapping from input streams to output streams.
745 Just enumerate the input streams in the order you want them in the output.
746 @var{sync_stream_id} if specified sets the input stream to sync
748 @item -map_meta_data @var{outfile}:@var{infile}
749 Set meta data information of @var{outfile} from @var{infile}.
751 Print specific debug info.
753 Add timings for benchmarking.
755 Dump each input packet.
757 When dumping packets, also dump the payload.
759 Only use bit exact algorithms (for codec testing).
761 Set RTP payload size in bytes.
763 Read input at native frame rate. Mainly used to simulate a grab device.
765 Loop over the input stream. Currently it works only for image
766 streams. This option is used for automatic FFserver testing.
767 @item -loop_output @var{number_of_times}
768 Repeatedly loop output for formats that support looping such as animated GIF
769 (0 will loop the output infinitely).
770 @item -threads @var{count}
772 @item -vsync @var{parameter}
773 Video sync method. Video will be stretched/squeezed to match the timestamps,
774 it is done by duplicating and dropping frames. With -map you can select from
775 which stream the timestamps should be taken. You can leave either video or
776 audio unchanged and sync the remaining stream(s) to the unchanged one.
777 @item -async @var{samples_per_second}
778 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
779 the parameter is the maximum samples per second by which the audio is changed.
780 -async 1 is a special case where only the start of the audio stream is corrected
781 without any later correction.
783 Copy timestamps from input to output.
785 Finish encoding when the shortest input stream ends.
786 @item -dts_delta_threshold
787 Timestamp discontinuity delta threshold.
788 @item -muxdelay @var{seconds}
789 Set the maximum demux-decode delay.
790 @item -muxpreload @var{seconds}
791 Set the initial demux-decode delay.
794 @section Preset files
796 A preset file contains a sequence of @var{option}=@var{value} pairs,
797 one for each line, specifying a sequence of options which would be
798 awkward to specify on the command line. Lines starting with the hash
799 ('#') character are ignored and are used to provide comments. Check
800 the @file{ffpresets} directory in the FFmpeg source tree for examples.
802 Preset files are specified with the @code{vpre}, @code{apre} and
803 @code{spre} options. The options specified in a preset file are
804 applied to the currently selected codec of the same type as the preset
807 The argument passed to the preset options identifies the preset file
808 to use according to the following rules.
810 First ffmpeg searches for a file named @var{arg}.ffpreset in the
811 directories @file{$HOME/.ffmpeg}, and in the datadir defined at
812 configuration time (usually @file{PREFIX/share/ffmpeg}) in that
813 order. For example, if the argument is @code{libx264-max}, it will
814 search for the file @file{libx264-max.ffpreset}.
816 If no such file is found, then ffmpeg will search for a file named
817 @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
818 directories, where @var{codec_name} is the name of the codec to which
819 the preset file options will be applied. For example, if you select
820 the video codec with @code{-vcodec libx264} and use @code{-vpre max},
821 then it will search for the file @file{libx264-max.ffpreset}.
823 Finally, if the above rules failed and the argument specifies an
824 absolute pathname, ffmpeg will search for that filename. This way you
825 can specify the absolute and complete filename of the preset file, for
826 example @file{./ffpresets/libx264-max.ffpreset}.
828 @node FFmpeg formula evaluator
829 @section FFmpeg formula evaluator
831 When evaluating a rate control string, FFmpeg uses an internal formula
834 The following binary operators are available: @code{+}, @code{-},
835 @code{*}, @code{/}, @code{^}.
837 The following unary operators are available: @code{+}, @code{-},
840 The following statements are available: @code{ld}, @code{st},
843 The following functions are available:
871 The following constants are available:
900 @settitle FFmpeg video converter
903 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
914 The file name can be @file{-} to read from standard input or to write
917 FFmpeg also handles many protocols specified with an URL syntax.
919 Use 'ffmpeg -formats' to see a list of the supported protocols.
921 The protocol @code{http:} is currently used only to communicate with
922 FFserver (see the FFserver documentation). When FFmpeg will be a
923 video player it will also be used for streaming :-)
928 @item For streaming at very low bitrate application, use a low frame rate
929 and a small GOP size. This is especially true for RealVideo where
930 the Linux player does not seem to be very fast, so it can miss
931 frames. An example is:
934 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
937 @item The parameter 'q' which is displayed while encoding is the current
938 quantizer. The value 1 indicates that a very good quality could
939 be achieved. The value 31 indicates the worst quality. If q=31 appears
940 too often, it means that the encoder cannot compress enough to meet
941 your bitrate. You must either increase the bitrate, decrease the
942 frame rate or decrease the frame size.
944 @item If your computer is not fast enough, you can speed up the
945 compression at the expense of the compression ratio. You can use
946 '-me zero' to speed up motion estimation, and '-intra' to disable
947 motion estimation completely (you have only I-frames, which means it
948 is about as good as JPEG compression).
950 @item To have very low audio bitrates, reduce the sampling frequency
951 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
953 @item To have a constant quality (but a variable bitrate), use the option
954 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
957 @item When converting video files, you can use the '-sameq' option which
958 uses the same quality factor in the encoder as in the decoder.
959 It allows almost lossless encoding.