1 \input texinfo @c -*- texinfo -*-
3 @settitle FFmpeg Documentation
6 @center @titlefont{FFmpeg Documentation}
13 FFmpeg is a very fast video and audio converter. It can also grab from
14 a live audio/video source.
16 The command line interface is designed to be intuitive, in the sense
17 that FFmpeg tries to figure out all parameters that can possibly be
18 derived automatically. You usually only have to specify the target
21 FFmpeg can also convert from any sample rate to any other, and resize
22 video on the fly with a high quality polyphase filter.
27 @section Video and Audio grabbing
29 FFmpeg can grab video and audio from devices given that you specify the input
33 ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
36 Note that you must activate the right video source and channel before
37 launching FFmpeg with any TV viewer such as xawtv
38 (@url{http://bytesex.org/xawtv/}) by Gerd Knorr. You also
39 have to set the audio recording levels correctly with a
44 FFmpeg can grab the X11 display.
47 ffmpeg -f x11grab -s cif -i :0.0 /tmp/out.mpg
50 0.0 is display.screen number of your X11 server, same as
51 the DISPLAY environment variable.
54 ffmpeg -f x11grab -s cif -i :0.0+10,20 /tmp/out.mpg
57 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
58 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
60 @section Video and Audio file format conversion
62 * FFmpeg can use any supported file format and protocol as input:
66 * You can use YUV files as input:
69 ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
72 It will use the files:
74 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
75 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
78 The Y files use twice the resolution of the U and V files. They are
79 raw files, without header. They can be generated by all decent video
80 decoders. You must specify the size of the image with the @option{-s} option
81 if FFmpeg cannot guess it.
83 * You can input from a raw YUV420P file:
86 ffmpeg -i /tmp/test.yuv /tmp/out.avi
89 test.yuv is a file containing raw YUV planar data. Each frame is composed
90 of the Y plane followed by the U and V planes at half vertical and
91 horizontal resolution.
93 * You can output to a raw YUV420P file:
96 ffmpeg -i mydivx.avi hugefile.yuv
99 * You can set several input files and output files:
102 ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
105 Converts the audio file a.wav and the raw YUV video file a.yuv
108 * You can also do audio and video conversions at the same time:
111 ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
114 Converts a.wav to MPEG audio at 22050Hz sample rate.
116 * You can encode to several formats at the same time and define a
117 mapping from input stream to output streams:
120 ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
123 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
124 file:index' specifies which input stream is used for each output
125 stream, in the order of the definition of output streams.
127 * You can transcode decrypted VOBs:
130 ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 128k snatch.avi
133 This is a typical DVD ripping example; the input is a VOB file, the
134 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
135 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
136 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
137 input video. Furthermore, the audio stream is MP3-encoded so you need
138 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
139 The mapping is particularly useful for DVD transcoding
140 to get the desired audio language.
142 NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
149 The generic syntax is:
152 @c man begin SYNOPSIS
153 ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
156 @c man begin DESCRIPTION
157 As a general rule, options are applied to the next specified
158 file. Therefore, order is important, and you can have the same
159 option on the command line multiple times. Each occurrence is
160 then applied to the next input or output file.
162 * To set the video bitrate of the output file to 64kbit/s:
164 ffmpeg -i input.avi -b 64k output.avi
167 * To force the frame rate of the input and output file to 24 fps:
169 ffmpeg -r 24 -i input.avi output.avi
172 * To force the frame rate of the output file to 24 fps:
174 ffmpeg -i input.avi -r 24 output.avi
177 * To force the frame rate of input file to 1 fps and the output file to 24 fps:
179 ffmpeg -r 1 -i input.avi -r 24 output.avi
182 The format option may be needed for raw input files.
184 By default, FFmpeg tries to convert as losslessly as possible: It
185 uses the same audio and video parameters for the outputs as the one
186 specified for the inputs.
190 @section Main options
203 Show available formats, codecs, protocols, ...
208 @item -i @var{filename}
212 Overwrite output files.
214 @item -t @var{duration}
215 Restrict the transcoded/captured video sequence
216 to the duration specified in seconds.
217 @code{hh:mm:ss[.xxx]} syntax is also supported.
219 @item -fs @var{limit_size}
220 Set the file size limit.
222 @item -ss @var{position}
223 Seek to given time position in seconds.
224 @code{hh:mm:ss[.xxx]} syntax is also supported.
226 @item -itsoffset @var{offset}
227 Set the input time offset in seconds.
228 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
229 This option affects all the input files that follow it.
230 The offset is added to the timestamps of the input files.
231 Specifying a positive offset means that the corresponding
232 streams are delayed by 'offset' seconds.
234 @item -title @var{string}
237 @item -timestamp @var{time}
240 @item -author @var{string}
243 @item -copyright @var{string}
246 @item -comment @var{string}
249 @item -album @var{string}
252 @item -track @var{number}
255 @item -year @var{number}
258 @item -v @var{number}
259 Set the logging verbosity level.
261 @item -target @var{type}
262 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
263 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
264 buffer sizes) are then set automatically. You can just type:
267 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
270 Nevertheless you can specify additional options as long as you know
271 they do not conflict with the standard, as in:
274 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
277 @item -dframes @var{number}
278 Set the number of data frames to record.
280 @item -scodec @var{codec}
281 Force subtitle codec ('copy' to copy stream).
284 Add a new subtitle stream to the current output stream.
286 @item -slang @var{code}
287 Set the ISO 639 language code (3 letters) of the current subtitle stream.
291 @section Video Options
294 @item -b @var{bitrate}
295 Set the video bitrate in bit/s (default = 200 kb/s).
296 @item -vframes @var{number}
297 Set the number of video frames to record.
299 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
301 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
302 The following abbreviations are recognized:
362 @item -aspect @var{aspect}
363 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
364 @item -croptop @var{size}
365 Set top crop band size (in pixels).
366 @item -cropbottom @var{size}
367 Set bottom crop band size (in pixels).
368 @item -cropleft @var{size}
369 Set left crop band size (in pixels).
370 @item -cropright @var{size}
371 Set right crop band size (in pixels).
372 @item -padtop @var{size}
373 Set top pad band size (in pixels).
374 @item -padbottom @var{size}
375 Set bottom pad band size (in pixels).
376 @item -padleft @var{size}
377 Set left pad band size (in pixels).
378 @item -padright @var{size}
379 Set right pad band size (in pixels).
380 @item -padcolor @var{hex_color}
381 Set color of padded bands. The value for padcolor is expressed
382 as a six digit hexadecimal number where the first two digits
383 represent red, the middle two digits green and last two digits
384 blue (default = 000000 (black)).
386 Disable video recording.
387 @item -bt @var{tolerance}
388 Set video bitrate tolerance (in bit/s).
389 @item -maxrate @var{bitrate}
390 Set max video bitrate (in bit/s).
391 Requires -bufsize to be set.
392 @item -minrate @var{bitrate}
393 Set min video bitrate (in bit/s).
394 Most useful in setting up a CBR encode:
396 ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
398 It is of little use elsewise.
399 @item -bufsize @var{size}
400 Set video buffer verifier buffer size (in bits).
401 @item -vcodec @var{codec}
402 Force video codec to @var{codec}. Use the @code{copy} special value to
403 tell that the raw codec data must be copied as is.
405 Use same video quality as source (implies VBR).
408 Select the pass number (1 or 2). It is useful to do two pass
409 encoding. The statistics of the video are recorded in the first
410 pass and the video is generated at the exact requested bitrate
413 @item -passlogfile @var{file}
414 Set two pass logfile name to @var{file}.
417 Add a new video stream to the current output stream.
421 @section Advanced Video Options
424 @item -pix_fmt @var{format}
425 Set pixel format. Use 'list' as parameter to show all the supported
427 @item -sws_flags @var{flags}
428 Set SwScaler flags (only available when compiled with swscale support).
429 @item -g @var{gop_size}
430 Set the group of pictures size.
432 Use only intra frames.
435 @item -qscale @var{q}
436 Use fixed video quantizer scale (VBR).
438 minimum video quantizer scale (VBR)
440 maximum video quantizer scale (VBR)
442 maximum difference between the quantizer scales (VBR)
443 @item -qblur @var{blur}
444 video quantizer scale blur (VBR)
445 @item -qcomp @var{compression}
446 video quantizer scale compression (VBR)
448 @item -lmin @var{lambda}
449 minimum video lagrange factor (VBR)
450 @item -lmax @var{lambda}
451 max video lagrange factor (VBR)
452 @item -mblmin @var{lambda}
453 minimum macroblock quantizer scale (VBR)
454 @item -mblmax @var{lambda}
455 maximum macroblock quantizer scale (VBR)
457 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
458 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
460 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
463 @item -rc_init_cplx @var{complexity}
464 initial complexity for single pass encoding
465 @item -b_qfactor @var{factor}
466 qp factor between P- and B-frames
467 @item -i_qfactor @var{factor}
468 qp factor between P- and I-frames
469 @item -b_qoffset @var{offset}
470 qp offset between P- and B-frames
471 @item -i_qoffset @var{offset}
472 qp offset between P- and I-frames
473 @item -rc_eq @var{equation}
474 Set rate control equation (@pxref{FFmpeg formula
475 evaluator}) (default = @code{tex^qComp}).
476 @item -rc_override @var{override}
477 rate control override for specific intervals
478 @item -me_method @var{method}
479 Set motion estimation method to @var{method}.
480 Available methods are (from lowest to best quality):
483 Try just the (0, 0) vector.
492 exhaustive search (slow and marginally better than epzs)
495 @item -dct_algo @var{algo}
496 Set DCT algorithm to @var{algo}. Available values are:
499 FF_DCT_AUTO (default)
512 @item -idct_algo @var{algo}
513 Set IDCT algorithm to @var{algo}. Available values are:
516 FF_IDCT_AUTO (default)
540 Set error resilience to @var{n}.
543 FF_ER_CAREFUL (default)
549 FF_ER_VERY_AGGRESSIVE
552 @item -ec @var{bit_mask}
553 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
554 the following values:
557 FF_EC_GUESS_MVS (default = enabled)
559 FF_EC_DEBLOCK (default = enabled)
562 @item -bf @var{frames}
563 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
564 @item -mbd @var{mode}
568 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
570 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
572 FF_MB_DECISION_RD: rate distortion
576 Use four motion vector by macroblock (MPEG-4 only).
578 Use data partitioning (MPEG-4 only).
579 @item -bug @var{param}
580 Work around encoder bugs that are not auto-detected.
581 @item -strict @var{strictness}
582 How strictly to follow the standards.
584 Enable Advanced intra coding (h263+).
586 Enable Unlimited Motion Vector (h263+)
589 Deinterlace pictures.
591 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
592 Use this option if your input file is interlaced and you want
593 to keep the interlaced format for minimum losses.
594 The alternative is to deinterlace the input stream with
595 @option{-deinterlace}, but deinterlacing introduces losses.
597 Calculate PSNR of compressed frames.
599 Dump video coding statistics to @file{vstats_HHMMSS.log}.
600 @item -vstats_file @var{file}
601 Dump video coding statistics to @var{file}.
602 @item -vhook @var{module}
603 Insert video processing @var{module}. @var{module} contains the module
604 name and its parameters separated by spaces.
606 top=1/bottom=0/auto=-1 field first
607 @item -dc @var{precision}
609 @item -vtag @var{fourcc/tag}
610 Force video tag/fourcc.
613 @item -vbsf @var{bitstream_filter}
614 Bitstream filters available are "dump_extra", "remove_extra", "noise", "h264_mp4toannexb", "imxdump", "mjpegadump".
616 ffmpeg -i h264.mp4 -vcodec copy -vbsf h264_mp4toannexb -an out.h264
620 @section Audio Options
623 @item -aframes @var{number}
624 Set the number of audio frames to record.
626 Set the audio sampling frequency (default = 44100 Hz).
627 @item -ab @var{bitrate}
628 Set the audio bitrate in bit/s (default = 64k).
629 @item -ac @var{channels}
630 Set the number of audio channels (default = 1).
632 Disable audio recording.
633 @item -acodec @var{codec}
634 Force audio codec to @var{codec}. Use the @code{copy} special value to
635 specify that the raw codec data must be copied as is.
637 Add a new audio track to the output file. If you want to specify parameters,
638 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
640 Mapping will be done automatically, if the number of output streams is equal to
641 the number of input streams, else it will pick the first one that matches. You
642 can override the mapping using @code{-map} as usual.
646 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
648 @item -alang @var{code}
649 Set the ISO 639 language code (3 letters) of the current audio stream.
652 @section Advanced Audio options:
655 @item -atag @var{fourcc/tag}
656 Force audio tag/fourcc.
657 @item -absf @var{bitstream_filter}
658 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
661 @section Subtitle options:
664 @item -scodec @var{codec}
665 Force subtitle codec ('copy' to copy stream).
667 Add a new subtitle stream to the current output stream.
668 @item -slang @var{code}
669 Set the ISO 639 language code (3 letters) of the current subtitle stream.
670 @item -sbsf @var{bitstream_filter}
671 Bitstream filters available are "mov2textsub", "text2movsub".
673 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -scodec copy -f rawvideo sub.txt
677 @section Audio/Video grab options
680 @item -vc @var{channel}
681 Set video grab channel (DV1394 only).
682 @item -tvstd @var{standard}
683 Set television standard (NTSC, PAL (SECAM)).
685 Synchronize read on input.
688 @section Advanced options
691 @item -map input stream id[:input stream id]
692 Set stream mapping from input streams to output streams.
693 Just enumerate the input streams in the order you want them in the output.
694 [input stream id] sets the (input) stream to sync against.
695 @item -map_meta_data @var{outfile}:@var{infile}
696 Set meta data information of @var{outfile} from @var{infile}.
698 Print specific debug info.
700 Add timings for benchmarking.
702 Dump each input packet.
704 When dumping packets, also dump the payload.
706 Only use bit exact algorithms (for codec testing).
708 Set packet size in bits.
710 Read input at native frame rate. Mainly used to simulate a grab device.
712 Loop over the input stream. Currently it works only for image
713 streams. This option is used for automatic FFserver testing.
714 @item -loop_output @var{number_of_times}
715 Repeatedly loop output for formats that support looping such as animated GIF
716 (0 will loop the output infinitely).
717 @item -threads @var{count}
719 @item -vsync @var{parameter}
720 Video sync method. Video will be stretched/squeezed to match the timestamps,
721 it is done by duplicating and dropping frames. With -map you can select from
722 which stream the timestamps should be taken. You can leave either video or
723 audio unchanged and sync the remaining stream(s) to the unchanged one.
724 @item -async @var{samples_per_second}
725 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
726 the parameter is the maximum samples per second by which the audio is changed.
727 -async 1 is a special case where only the start of the audio stream is corrected
728 without any later correction.
730 Copy timestamps from input to output.
732 Finish encoding when the shortest input stream ends.
733 @item -dts_delta_threshold
734 Timestamp discontinuity delta threshold.
735 @item -muxdelay @var{seconds}
736 Set the maximum demux-decode delay.
737 @item -muxpreload @var{seconds}
738 Set the initial demux-decode delay.
741 @node FFmpeg formula evaluator
742 @section FFmpeg formula evaluator
744 When evaluating a rate control string, FFmpeg uses an internal formula
747 The following binary operators are available: @code{+}, @code{-},
748 @code{*}, @code{/}, @code{^}.
750 The following unary operators are available: @code{+}, @code{-},
753 The following functions are available:
775 The following constants are available:
804 @settitle FFmpeg video converter
807 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
818 The file name can be @file{-} to read from standard input or to write
821 FFmpeg also handles many protocols specified with an URL syntax.
823 Use 'ffmpeg -formats' to see a list of the supported protocols.
825 The protocol @code{http:} is currently used only to communicate with
826 FFserver (see the FFserver documentation). When FFmpeg will be a
827 video player it will also be used for streaming :-)
832 @item For streaming at very low bitrate application, use a low frame rate
833 and a small GOP size. This is especially true for RealVideo where
834 the Linux player does not seem to be very fast, so it can miss
835 frames. An example is:
838 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
841 @item The parameter 'q' which is displayed while encoding is the current
842 quantizer. The value 1 indicates that a very good quality could
843 be achieved. The value 31 indicates the worst quality. If q=31 appears
844 too often, it means that the encoder cannot compress enough to meet
845 your bitrate. You must either increase the bitrate, decrease the
846 frame rate or decrease the frame size.
848 @item If your computer is not fast enough, you can speed up the
849 compression at the expense of the compression ratio. You can use
850 '-me zero' to speed up motion estimation, and '-intra' to disable
851 motion estimation completely (you have only I-frames, which means it
852 is about as good as JPEG compression).
854 @item To have very low audio bitrates, reduce the sampling frequency
855 (down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
857 @item To have a constant quality (but a variable bitrate), use the option
858 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
861 @item When converting video files, you can use the '-sameq' option which
862 uses the same quality factor in the encoder as in the decoder.
863 It allows almost lossless encoding.