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:
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, bitstream filters, protocols, and frame size and frame rate abbreviations.
234 The fields preceding the format and codec names have the following meanings:
241 Video/audio/subtitle codec
243 Codec supports slices
245 Codec supports direct rendering
247 Codec can handle input truncated at random locations instead of only at frame boundaries
253 @item -i @var{filename}
257 Overwrite output files.
259 @item -t @var{duration}
260 Restrict the transcoded/captured video sequence
261 to the duration specified in seconds.
262 @code{hh:mm:ss[.xxx]} syntax is also supported.
264 @item -fs @var{limit_size}
265 Set the file size limit.
267 @item -ss @var{position}
268 Seek to given time position in seconds.
269 @code{hh:mm:ss[.xxx]} syntax is also supported.
271 @item -itsoffset @var{offset}
272 Set the input time offset in seconds.
273 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
274 This option affects all the input files that follow it.
275 The offset is added to the timestamps of the input files.
276 Specifying a positive offset means that the corresponding
277 streams are delayed by 'offset' seconds.
279 @item -title @var{string}
282 @item -timestamp @var{time}
285 @item -author @var{string}
288 @item -copyright @var{string}
291 @item -comment @var{string}
294 @item -album @var{string}
297 @item -track @var{number}
300 @item -year @var{number}
303 @item -v @var{number}
304 Set the logging verbosity level.
306 @item -target @var{type}
307 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
308 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
309 buffer sizes) are then set automatically. You can just type:
312 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
315 Nevertheless you can specify additional options as long as you know
316 they do not conflict with the standard, as in:
319 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
322 @item -dframes @var{number}
323 Set the number of data frames to record.
325 @item -scodec @var{codec}
326 Force subtitle codec ('copy' to copy stream).
329 Add a new subtitle stream to the current output stream.
331 @item -slang @var{code}
332 Set the ISO 639 language code (3 letters) of the current subtitle stream.
336 @section Video Options
339 @item -b @var{bitrate}
340 Set the video bitrate in bit/s (default = 200 kb/s).
341 @item -vframes @var{number}
342 Set the number of video frames to record.
344 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
346 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
347 The following abbreviations are recognized:
407 @item -aspect @var{aspect}
408 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
409 @item -croptop @var{size}
410 Set top crop band size (in pixels).
411 @item -cropbottom @var{size}
412 Set bottom crop band size (in pixels).
413 @item -cropleft @var{size}
414 Set left crop band size (in pixels).
415 @item -cropright @var{size}
416 Set right crop band size (in pixels).
417 @item -padtop @var{size}
418 Set top pad band size (in pixels).
419 @item -padbottom @var{size}
420 Set bottom pad band size (in pixels).
421 @item -padleft @var{size}
422 Set left pad band size (in pixels).
423 @item -padright @var{size}
424 Set right pad band size (in pixels).
425 @item -padcolor @var{hex_color}
426 Set color of padded bands. The value for padcolor is expressed
427 as a six digit hexadecimal number where the first two digits
428 represent red, the middle two digits green and last two digits
429 blue (default = 000000 (black)).
431 Disable video recording.
432 @item -bt @var{tolerance}
433 Set video bitrate tolerance (in bits, default 4000k).
434 Has a minimum value of: (target_bitrate/target_framerate).
435 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
436 willing to deviate from the target average bitrate value. This is
437 not related to min/max bitrate. Lowering tolerance too much has
438 an adverse effect on quality.
439 @item -maxrate @var{bitrate}
440 Set max video bitrate (in bit/s).
441 Requires -bufsize to be set.
442 @item -minrate @var{bitrate}
443 Set min video bitrate (in bit/s).
444 Most useful in setting up a CBR encode:
446 ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
448 It is of little use elsewise.
449 @item -bufsize @var{size}
450 Set video buffer verifier buffer size (in bits).
451 @item -vcodec @var{codec}
452 Force video codec to @var{codec}. Use the @code{copy} special value to
453 tell that the raw codec data must be copied as is.
455 Use same video quality as source (implies VBR).
458 Select the pass number (1 or 2). It is used to do two-pass
459 video encoding. The statistics of the video are recorded in the first
460 pass into a log file (see also the option -passlogfile),
461 and in the second pass that log file is used to generate the video
462 at the exact requested bitrate.
463 On pass 1, you may just deactivate audio and set output to null,
464 examples for Windows and Unix:
466 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y NUL
467 ffmpeg -i foo.mov -vcodec libxvid -pass 1 -an -f rawvideo -y /dev/null
470 @item -passlogfile @var{prefix}
471 Set two-pass log file name prefix to @var{prefix}, the default file name
472 prefix is ``ffmpeg2pass''. The complete file name will be
473 @file{PREFIX-N.log}, where N is a number specific to the output
477 Add a new video stream to the current output stream.
481 @section Advanced Video Options
484 @item -pix_fmt @var{format}
485 Set pixel format. Use 'list' as parameter to show all the supported
487 @item -sws_flags @var{flags}
488 Set SwScaler flags (only available when compiled with swscale support).
489 @item -g @var{gop_size}
490 Set the group of pictures size.
492 Use only intra frames.
495 @item -qscale @var{q}
496 Use fixed video quantizer scale (VBR).
498 minimum video quantizer scale (VBR)
500 maximum video quantizer scale (VBR)
502 maximum difference between the quantizer scales (VBR)
503 @item -qblur @var{blur}
504 video quantizer scale blur (VBR) (range 0.0 - 1.0)
505 @item -qcomp @var{compression}
506 video quantizer scale compression (VBR) (default 0.5).
507 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
509 @item -lmin @var{lambda}
510 minimum video lagrange factor (VBR)
511 @item -lmax @var{lambda}
512 max video lagrange factor (VBR)
513 @item -mblmin @var{lambda}
514 minimum macroblock quantizer scale (VBR)
515 @item -mblmax @var{lambda}
516 maximum macroblock quantizer scale (VBR)
518 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
519 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
521 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
524 @item -rc_init_cplx @var{complexity}
525 initial complexity for single pass encoding
526 @item -b_qfactor @var{factor}
527 qp factor between P- and B-frames
528 @item -i_qfactor @var{factor}
529 qp factor between P- and I-frames
530 @item -b_qoffset @var{offset}
531 qp offset between P- and B-frames
532 @item -i_qoffset @var{offset}
533 qp offset between P- and I-frames
534 @item -rc_eq @var{equation}
535 Set rate control equation (@pxref{FFmpeg formula
536 evaluator}) (default = @code{tex^qComp}).
537 @item -rc_override @var{override}
538 rate control override for specific intervals
539 @item -me_method @var{method}
540 Set motion estimation method to @var{method}.
541 Available methods are (from lowest to best quality):
544 Try just the (0, 0) vector.
553 exhaustive search (slow and marginally better than epzs)
556 @item -dct_algo @var{algo}
557 Set DCT algorithm to @var{algo}. Available values are:
560 FF_DCT_AUTO (default)
573 @item -idct_algo @var{algo}
574 Set IDCT algorithm to @var{algo}. Available values are:
577 FF_IDCT_AUTO (default)
601 Set error resilience to @var{n}.
604 FF_ER_CAREFUL (default)
610 FF_ER_VERY_AGGRESSIVE
613 @item -ec @var{bit_mask}
614 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
615 the following values:
618 FF_EC_GUESS_MVS (default = enabled)
620 FF_EC_DEBLOCK (default = enabled)
623 @item -bf @var{frames}
624 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
625 @item -mbd @var{mode}
629 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
631 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
633 FF_MB_DECISION_RD: rate distortion
637 Use four motion vector by macroblock (MPEG-4 only).
639 Use data partitioning (MPEG-4 only).
640 @item -bug @var{param}
641 Work around encoder bugs that are not auto-detected.
642 @item -strict @var{strictness}
643 How strictly to follow the standards.
645 Enable Advanced intra coding (h263+).
647 Enable Unlimited Motion Vector (h263+)
650 Deinterlace pictures.
652 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
653 Use this option if your input file is interlaced and you want
654 to keep the interlaced format for minimum losses.
655 The alternative is to deinterlace the input stream with
656 @option{-deinterlace}, but deinterlacing introduces losses.
658 Calculate PSNR of compressed frames.
660 Dump video coding statistics to @file{vstats_HHMMSS.log}.
661 @item -vstats_file @var{file}
662 Dump video coding statistics to @var{file}.
663 @item -vhook @var{module}
664 Insert video processing @var{module}. @var{module} contains the module
665 name and its parameters separated by spaces.
667 top=1/bottom=0/auto=-1 field first
668 @item -dc @var{precision}
670 @item -vtag @var{fourcc/tag}
671 Force video tag/fourcc.
674 @item -vbsf @var{bitstream_filter}
675 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
677 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
681 @section Audio Options
684 @item -aframes @var{number}
685 Set the number of audio frames to record.
687 Set the audio sampling frequency (default = 44100 Hz).
688 @item -ab @var{bitrate}
689 Set the audio bitrate in bit/s (default = 64k).
690 @item -ac @var{channels}
691 Set the number of audio channels (default = 1).
693 Disable audio recording.
694 @item -acodec @var{codec}
695 Force audio codec to @var{codec}. Use the @code{copy} special value to
696 specify that the raw codec data must be copied as is.
698 Add a new audio track to the output file. If you want to specify parameters,
699 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
701 Mapping will be done automatically, if the number of output streams is equal to
702 the number of input streams, else it will pick the first one that matches. You
703 can override the mapping using @code{-map} as usual.
707 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
709 @item -alang @var{code}
710 Set the ISO 639 language code (3 letters) of the current audio stream.
713 @section Advanced Audio options:
716 @item -atag @var{fourcc/tag}
717 Force audio tag/fourcc.
718 @item -absf @var{bitstream_filter}
719 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
722 @section Subtitle options:
725 @item -scodec @var{codec}
726 Force subtitle codec ('copy' to copy stream).
728 Add a new subtitle stream to the current output stream.
729 @item -slang @var{code}
730 Set the ISO 639 language code (3 letters) of the current subtitle stream.
731 @item -sbsf @var{bitstream_filter}
732 Bitstream filters available are "mov2textsub", "text2movsub".
734 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
738 @section Audio/Video grab options
741 @item -vc @var{channel}
742 Set video grab channel (DV1394 only).
743 @item -tvstd @var{standard}
744 Set television standard (NTSC, PAL (SECAM)).
746 Synchronize read on input.
749 @section Advanced options
752 @item -map @var{input_stream_id}[:@var{sync_stream_id}]
753 Set stream mapping from input streams to output streams.
754 Just enumerate the input streams in the order you want them in the output.
755 @var{sync_stream_id} if specified sets the input stream to sync
757 @item -map_meta_data @var{outfile}:@var{infile}
758 Set meta data information of @var{outfile} from @var{infile}.
760 Print specific debug info.
762 Add timings for benchmarking.
764 Dump each input packet.
766 When dumping packets, also dump the payload.
768 Only use bit exact algorithms (for codec testing).
770 Set packet size in bits.
772 Read input at native frame rate. Mainly used to simulate a grab device.
774 Loop over the input stream. Currently it works only for image
775 streams. This option is used for automatic FFserver testing.
776 @item -loop_output @var{number_of_times}
777 Repeatedly loop output for formats that support looping such as animated GIF
778 (0 will loop the output infinitely).
779 @item -threads @var{count}
781 @item -vsync @var{parameter}
782 Video sync method. Video will be stretched/squeezed to match the timestamps,
783 it is done by duplicating and dropping frames. With -map you can select from
784 which stream the timestamps should be taken. You can leave either video or
785 audio unchanged and sync the remaining stream(s) to the unchanged one.
786 @item -async @var{samples_per_second}
787 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
788 the parameter is the maximum samples per second by which the audio is changed.
789 -async 1 is a special case where only the start of the audio stream is corrected
790 without any later correction.
792 Copy timestamps from input to output.
794 Finish encoding when the shortest input stream ends.
795 @item -dts_delta_threshold
796 Timestamp discontinuity delta threshold.
797 @item -muxdelay @var{seconds}
798 Set the maximum demux-decode delay.
799 @item -muxpreload @var{seconds}
800 Set the initial demux-decode delay.
803 @section Preset files
805 A preset file contains a sequence of @var{option}=@var{value} pairs,
806 one for each line, specifying a sequence of options which would be
807 awkward to specify on the command line. Lines starting with the hash
808 ('#') character are ignored and are used to provide comments. Check
809 the @file{ffpresets} directory in the FFmpeg source tree for examples.
811 Preset files are specified with the @code{vpre}, @code{apre} and
812 @code{spre} options. The options specified in a preset file are
813 applied to the currently selected codec of the same type as the preset
816 The argument passed to the preset options identifies the preset file
817 to use according to the following rules.
819 First ffmpeg searches for a file named @var{arg}.ffpreset in the
820 directories @file{$HOME/.ffmpeg}, and in the datadir defined at
821 configuration time (usually @file{PREFIX/share/ffmpeg}) in that
822 order. For example, if the argument is @code{libx264-max}, it will
823 search for the file @file{libx264-max.ffpreset}.
825 If no such file is found, then ffmpeg will search for a file named
826 @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
827 directories, where @var{codec_name} is the name of the codec to which
828 the preset file options will be applied. For example, if you select
829 the video codec with @code{-vcodec libx264} and use @code{-vpre max},
830 then it will search for the file @file{libx264-max.ffpreset}.
832 Finally, if the above rules failed and the argument specifies an
833 absolute pathname, ffmpeg will search for that filename. This way you
834 can specify the absolute and complete filename of the preset file, for
835 example @file{./ffpresets/libx264-max.ffpreset}.
837 @node FFmpeg formula evaluator
838 @section FFmpeg formula evaluator
840 When evaluating a rate control string, FFmpeg uses an internal formula
843 The following binary operators are available: @code{+}, @code{-},
844 @code{*}, @code{/}, @code{^}.
846 The following unary operators are available: @code{+}, @code{-},
849 The following statements are available: @code{ld}, @code{st},
852 The following functions are available:
880 The following constants are available:
909 @settitle FFmpeg video converter
912 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
923 The file name can be @file{-} to read from standard input or to write
926 FFmpeg also handles many protocols specified with an URL syntax.
928 Use 'ffmpeg -formats' to see a list of the supported protocols.
930 The protocol @code{http:} is currently used only to communicate with
931 FFserver (see the FFserver documentation). When FFmpeg will be a
932 video player it will also be used for streaming :-)
937 @item For streaming at very low bitrate application, use a low frame rate
938 and a small GOP size. This is especially true for RealVideo where
939 the Linux player does not seem to be very fast, so it can miss
940 frames. An example is:
943 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
946 @item The parameter 'q' which is displayed while encoding is the current
947 quantizer. The value 1 indicates that a very good quality could
948 be achieved. The value 31 indicates the worst quality. If q=31 appears
949 too often, it means that the encoder cannot compress enough to meet
950 your bitrate. You must either increase the bitrate, decrease the
951 frame rate or decrease the frame size.
953 @item If your computer is not fast enough, you can speed up the
954 compression at the expense of the compression ratio. You can use
955 '-me zero' to speed up motion estimation, and '-intra' to disable
956 motion estimation completely (you have only I-frames, which means it
957 is about as good as JPEG compression).
959 @item To have very low audio bitrates, reduce the sampling frequency
960 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
962 @item To have a constant quality (but a variable bitrate), use the option
963 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
966 @item When converting video files, you can use the '-sameq' option which
967 uses the same quality factor in the encoder as in the decoder.
968 It allows almost lossless encoding.