1 \input texinfo @c -*- texinfo -*-
3 @settitle ffmpeg Documentation
5 @center @titlefont{ffmpeg Documentation}
14 The generic syntax is:
18 ffmpeg [global options] [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
23 @c man begin DESCRIPTION
25 ffmpeg is a very fast video and audio converter that can also grab from
26 a live audio/video source. It can also convert between arbitrary sample
27 rates and resize video on the fly with a high quality polyphase filter.
29 As a general rule, options are applied to the next specified
30 file. Therefore, order is important, and you can have the same
31 option on the command line multiple times. Each occurrence is
32 then applied to the next input or output file.
33 Exceptions from this rule are the global options (e.g. verbosity level),
34 which should be specified first.
38 To set the video bitrate of the output file to 64kbit/s:
40 ffmpeg -i input.avi -b:v 64k output.avi
44 To force the frame rate of the output file to 24 fps:
46 ffmpeg -i input.avi -r 24 output.avi
50 To force the frame rate of the input file (valid for raw formats only)
51 to 1 fps and the frame rate of the output file to 24 fps:
53 ffmpeg -r 1 -i input.m2v -r 24 output.avi
57 The format option may be needed for raw input files.
59 @c man end DESCRIPTION
61 @chapter Stream selection
62 @c man begin STREAM SELECTION
64 By default ffmpeg includes only one stream of each type (video, audio, subtitle)
65 present in the input files and adds them to each output file. It picks the
66 "best" of each based upon the following criteria; for video it is the stream
67 with the highest resolution, for audio the stream with the most channels, for
68 subtitle it's the first subtitle stream. In the case where several streams of
69 the same type rate equally, the lowest numbered stream is chosen.
71 You can disable some of those defaults by using @code{-vn/-an/-sn} options. For
72 full manual control, use the @code{-map} option, which disables the defaults just
75 @c man end STREAM SELECTION
80 @include avtools-common-opts.texi
86 @item -f @var{fmt} (@emph{input/output})
87 Force input or output file format. The format is normally auto detected for input
88 files and guessed from file extension for output files, so this option is not
91 @item -i @var{filename} (@emph{input})
94 @item -y (@emph{global})
95 Overwrite output files without asking.
97 @item -n (@emph{global})
98 Do not overwrite output files but exit if file exists.
100 @item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
101 @itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
102 Select an encoder (when used before an output file) or a decoder (when used
103 before an input file) for one or more streams. @var{codec} is the name of a
104 decoder/encoder or a special value @code{copy} (output only) to indicate that
105 the stream is not to be re-encoded.
109 ffmpeg -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
111 encodes all video streams with libx264 and copies all audio streams.
113 For each stream, the last matching @code{c} option is applied, so
115 ffmpeg -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
117 will copy all the streams except the second video, which will be encoded with
118 libx264, and the 138th audio, which will be encoded with libvorbis.
120 @item -t @var{duration} (@emph{output})
121 Stop writing the output after its duration reaches @var{duration}.
122 @var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
124 @item -fs @var{limit_size} (@emph{output})
125 Set the file size limit.
127 @item -ss @var{position} (@emph{input/output})
128 When used as an input option (before @code{-i}), seeks in this input file to
129 @var{position}. When used as an output option (before an output filename),
130 decodes but discards input until the timestamps reach @var{position}. This is
131 slower, but more accurate.
133 @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
135 @item -itsoffset @var{offset} (@emph{input})
136 Set the input time offset in seconds.
137 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
138 The offset is added to the timestamps of the input files.
139 Specifying a positive offset means that the corresponding
140 streams are delayed by @var{offset} seconds.
142 @item -timestamp @var{time} (@emph{output})
143 Set the recording timestamp in the container.
144 The syntax for @var{time} is:
146 now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[.m...]]])|(HH[MM[SS[.m...]]]))[Z|z])
148 If the value is "now" it takes the current time.
149 Time is local time unless 'Z' or 'z' is appended, in which case it is
151 If the year-month-day part is not specified it takes the current
154 @item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
155 Set a metadata key/value pair.
157 An optional @var{metadata_specifier} may be given to set metadata
158 on streams or chapters. See @code{-map_metadata} documentation for
161 This option overrides metadata set with @code{-map_metadata}. It is
162 also possible to delete metadata by using an empty value.
164 For example, for setting the title in the output file:
166 ffmpeg -i in.avi -metadata title="my title" out.flv
169 To set the language of the second stream:
171 ffmpeg -i INPUT -metadata:s:1 language=eng OUTPUT
174 @item -v @var{number} (@emph{global})
175 This option is deprecated and has no effect, use -loglevel
176 to set verbosity level.
178 @item -target @var{type} (@emph{output})
179 Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
180 @code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
181 @code{film-} to use the corresponding standard. All the format options
182 (bitrate, codecs, buffer sizes) are then set automatically. You can just type:
185 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
188 Nevertheless you can specify additional options as long as you know
189 they do not conflict with the standard, as in:
192 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
195 @item -dframes @var{number} (@emph{output})
196 Set the number of data frames to record. This is an alias for @code{-frames:d}.
198 @item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
199 Stop writing to the stream after @var{framecount} frames.
201 @item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
202 @itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
203 Use fixed quality scale (VBR). The meaning of @var{q} is
206 @item -filter[:@var{stream_specifier}] @var{filter_graph}
207 @var{filter_graph} is a description of the filter graph to apply to
208 the stream. Use @code{-filters} to show all the available filters
209 (including also sources and sinks).
213 @section Video Options
216 @item -vframes @var{number} (@emph{output})
217 Set the number of video frames to record. This is an alias for @code{-frames:v}.
218 @item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
219 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
220 @item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
221 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
222 The following abbreviations are recognized:
284 @item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
285 Set the video display aspect ratio specified by @var{aspect}.
287 @var{aspect} can be a floating point number string, or a string of the
288 form @var{num}:@var{den}, where @var{num} and @var{den} are the
289 numerator and denominator of the aspect ratio. For example "4:3",
290 "16:9", "1.3333", and "1.7777" are valid argument values.
292 @item -croptop @var{size}
293 @item -cropbottom @var{size}
294 @item -cropleft @var{size}
295 @item -cropright @var{size}
296 All the crop options have been removed. Use -vf
297 crop=width:height:x:y instead.
299 @item -padtop @var{size}
300 @item -padbottom @var{size}
301 @item -padleft @var{size}
302 @item -padright @var{size}
303 @item -padcolor @var{hex_color}
304 All the pad options have been removed. Use -vf
305 pad=width:height:x:y:color instead.
307 @item -vn (@emph{output})
308 Disable video recording.
309 @item -bt @var{tolerance}
310 Set video bitrate tolerance (in bits, default 4000k).
311 Has a minimum value of: (target_bitrate/target_framerate).
312 In 1-pass mode, bitrate tolerance specifies how far ratecontrol is
313 willing to deviate from the target average bitrate value. This is
314 not related to min/max bitrate. Lowering tolerance too much has
315 an adverse effect on quality.
316 @item -maxrate @var{bitrate}
317 Set max video bitrate (in bit/s).
318 Requires -bufsize to be set.
319 @item -minrate @var{bitrate}
320 Set min video bitrate (in bit/s).
321 Most useful in setting up a CBR encode:
323 ffmpeg -i myfile.avi -b:v 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
325 It is of little use elsewise.
326 @item -bufsize @var{size}
327 Set video buffer verifier buffer size (in bits).
328 @item -vcodec @var{codec} (@emph{output})
329 Set the video codec. This is an alias for @code{-codec:v}.
331 Use same quantizer as source (implies VBR).
333 Note that this is NOT SAME QUALITY. Do not use this option unless you know you
337 Select the pass number (1 or 2). It is used to do two-pass
338 video encoding. The statistics of the video are recorded in the first
339 pass into a log file (see also the option -passlogfile),
340 and in the second pass that log file is used to generate the video
341 at the exact requested bitrate.
342 On pass 1, you may just deactivate audio and set output to null,
343 examples for Windows and Unix:
345 ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
346 ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
349 @item -passlogfile @var{prefix} (@emph{global})
350 Set two-pass log file name prefix to @var{prefix}, the default file name
351 prefix is ``ffmpeg2pass''. The complete file name will be
352 @file{PREFIX-N.log}, where N is a number specific to the output
355 @item -vlang @var{code}
356 Set the ISO 639 language code (3 letters) of the current video stream.
358 @item -vf @var{filter_graph} (@emph{output})
359 @var{filter_graph} is a description of the filter graph to apply to
361 Use the option "-filters" to show all the available filters (including
362 also sources and sinks). This is an alias for @code{-filter:v}.
366 @section Advanced Video Options
369 @item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream})
370 Set pixel format. Use @code{-pix_fmts} to show all the supported
372 @item -sws_flags @var{flags} (@emph{input/output})
374 @item -g @var{gop_size}
375 Set the group of pictures size.
381 minimum video quantizer scale (VBR)
383 maximum video quantizer scale (VBR)
385 maximum difference between the quantizer scales (VBR)
386 @item -qblur @var{blur}
387 video quantizer scale blur (VBR) (range 0.0 - 1.0)
388 @item -qcomp @var{compression}
389 video quantizer scale compression (VBR) (default 0.5).
390 Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0
392 @item -lmin @var{lambda}
393 minimum video lagrange factor (VBR)
394 @item -lmax @var{lambda}
395 max video lagrange factor (VBR)
396 @item -mblmin @var{lambda}
397 minimum macroblock quantizer scale (VBR)
398 @item -mblmax @var{lambda}
399 maximum macroblock quantizer scale (VBR)
401 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
402 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
404 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
407 @item -rc_init_cplx @var{complexity}
408 initial complexity for single pass encoding
409 @item -b_qfactor @var{factor}
410 qp factor between P- and B-frames
411 @item -i_qfactor @var{factor}
412 qp factor between P- and I-frames
413 @item -b_qoffset @var{offset}
414 qp offset between P- and B-frames
415 @item -i_qoffset @var{offset}
416 qp offset between P- and I-frames
417 @item -rc_eq @var{equation}
418 Set rate control equation (see section "Expression Evaluation")
419 (default = @code{tex^qComp}).
421 When computing the rate control equation expression, besides the
422 standard functions defined in the section "Expression Evaluation", the
423 following functions are available:
429 and the following constants are available:
451 @item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream})
452 Rate control override for specific intervals, formatted as "int,int,int"
453 list separated with slashes. Two first values are the beginning and
454 end frame numbers, last one is quantizer to use if positive, or quality
456 @item -me_method @var{method}
457 Set motion estimation method to @var{method}.
458 Available methods are (from lowest to best quality):
461 Try just the (0, 0) vector.
470 exhaustive search (slow and marginally better than epzs)
473 @item -dct_algo @var{algo}
474 Set DCT algorithm to @var{algo}. Available values are:
477 FF_DCT_AUTO (default)
490 @item -idct_algo @var{algo}
491 Set IDCT algorithm to @var{algo}. Available values are:
494 FF_IDCT_AUTO (default)
518 Set error resilience to @var{n}.
521 FF_ER_CAREFUL (default)
527 FF_ER_VERY_AGGRESSIVE
530 @item -ec @var{bit_mask}
531 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
532 the following values:
535 FF_EC_GUESS_MVS (default = enabled)
537 FF_EC_DEBLOCK (default = enabled)
540 @item -bf @var{frames}
541 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
542 @item -mbd @var{mode}
546 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in ffmpeg).
548 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
550 FF_MB_DECISION_RD: rate distortion
554 Use four motion vector by macroblock (MPEG-4 only).
556 Use data partitioning (MPEG-4 only).
557 @item -bug @var{param}
558 Work around encoder bugs that are not auto-detected.
559 @item -strict @var{strictness}
560 How strictly to follow the standards.
562 Enable Advanced intra coding (h263+).
564 Enable Unlimited Motion Vector (h263+)
567 Deinterlace pictures.
569 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
570 Use this option if your input file is interlaced and you want
571 to keep the interlaced format for minimum losses.
572 The alternative is to deinterlace the input stream with
573 @option{-deinterlace}, but deinterlacing introduces losses.
575 Calculate PSNR of compressed frames.
577 Dump video coding statistics to @file{vstats_HHMMSS.log}.
578 @item -vstats_file @var{file}
579 Dump video coding statistics to @var{file}.
580 @item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
581 top=1/bottom=0/auto=-1 field first
582 @item -dc @var{precision}
584 @item -vtag @var{fourcc/tag} (@emph{output})
585 Force video tag/fourcc. This is an alias for @code{-tag:v}.
586 @item -qphist (@emph{global})
588 @item -vbsf @var{bitstream_filter}
590 @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
591 Force key frames at the specified timestamps, more precisely at the first
592 frames after each specified time.
593 This option can be useful to ensure that a seek point is present at a
594 chapter mark or any other designated place in the output file.
595 The timestamps must be specified in ascending order.
598 @section Audio Options
601 @item -aframes @var{number} (@emph{output})
602 Set the number of audio frames to record. This is an alias for @code{-frames:a}.
603 @item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
604 Set the audio sampling frequency. For output streams it is set by
605 default to the frequency of the corresponding input stream. For input
606 streams this option only makes sense for audio grabbing devices and raw
607 demuxers and is mapped to the corresponding demuxer options.
608 @item -aq @var{q} (@emph{output})
609 Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
610 @item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
611 Set the number of audio channels. For output streams it is set by
612 default to the number of input audio channels. For input streams
613 this option only makes sense for audio grabbing devices and raw demuxers
614 and is mapped to the corresponding demuxer options.
615 @item -an (@emph{output})
616 Disable audio recording.
617 @item -acodec @var{codec} (@emph{input/output})
618 Set the audio codec. This is an alias for @code{-codec:a}.
619 @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
620 Set the audio sample format. Use @code{-help sample_fmts} to get a list
621 of supported sample formats.
624 @section Advanced Audio options:
627 @item -atag @var{fourcc/tag} (@emph{output})
628 Force audio tag/fourcc. This is an alias for @code{-tag:a}.
629 @item -audio_service_type @var{type}
630 Set the type of service that the audio stream contains.
633 Main Audio Service (default)
651 @item -absf @var{bitstream_filter}
655 @section Subtitle options:
658 @item -slang @var{code}
659 Set the ISO 639 language code (3 letters) of the current subtitle stream.
660 @item -scodec @var{codec} (@emph{input/output})
661 Set the subtitle codec. This is an alias for @code{-codec:s}.
662 @item -sn (@emph{output})
663 Disable subtitle recording.
664 @item -sbsf @var{bitstream_filter}
668 @section Audio/Video grab options
671 @item -isync (@emph{global})
672 Synchronize read on input.
675 @section Advanced options
678 @item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] (@emph{output})
680 Designate one or more input streams as a source for the output file. Each input
681 stream is identified by the input file index @var{input_file_id} and
682 the input stream index @var{input_stream_id} within the input
683 file. Both indices start at 0. If specified,
684 @var{sync_file_id}:@var{stream_specifier} sets which input stream
685 is used as a presentation sync reference.
687 The first @code{-map} option on the command line specifies the
688 source for output stream 0, the second @code{-map} option specifies
689 the source for output stream 1, etc.
691 A @code{-} character before the stream identifier creates a "negative" mapping.
692 It disables matching streams from already created mappings.
694 For example, to map ALL streams from the first input file to output
696 ffmpeg -i INPUT -map 0 output
699 For example, if you have two audio streams in the first input file,
700 these streams are identified by "0:0" and "0:1". You can use
701 @code{-map} to select which streams to place in an output file. For
704 ffmpeg -i INPUT -map 0:1 out.wav
706 will map the input stream in @file{INPUT} identified by "0:1" to
707 the (single) output stream in @file{out.wav}.
709 For example, to select the stream with index 2 from input file
710 @file{a.mov} (specified by the identifier "0:2"), and stream with
711 index 6 from input @file{b.mov} (specified by the identifier "1:6"),
712 and copy them to the output file @file{out.mov}:
714 ffmpeg -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
717 To select all video and the third audio stream from an input file:
719 ffmpeg -i INPUT -map 0:v -map 0:a:2 OUTPUT
722 To map all the streams except the second audio, use negative mappings
724 ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT
727 Note that using this option disables the default mappings for this output file.
729 @item -map_channel [@var{input_file_id}.@var{stream_specifier}.@var{channel_id}|-1][:@var{output_file_id}.@var{stream_specifier}]
730 Map an audio channel from a given input to an output. If
731 @var{output_file_id}.@var{stream_specifier} are not set, the audio channel will
732 be mapped on all the audio streams.
734 Using "-1" instead of
735 @var{input_file_id}.@var{stream_specifier}.@var{channel_id} will map a muted
738 For example, assuming @var{INPUT} is a stereo audio file, you can switch the
739 two audio channels with the following command:
741 ffmpeg -i INPUT -map_channel 0.0.1 -map_channel 0.0.0 OUTPUT
744 If you want to mute the first channel and keep the second:
746 ffmpeg -i INPUT -map_channel -1 -map_channel 0.0.1 OUTPUT
749 The order of the "-map_channel" option specifies the order of the channels in
750 the output stream. The output channel layout is guessed from the number of
751 channels mapped (mono if one "-map_channel", stereo if two, etc.). Using "-ac"
752 in combination of "-map_channel" makes the channel gain levels to be updated if
753 channel layouts don't match (for instance two "-map_channel" options and "-ac
756 You can also extract each channel of an @var{INPUT} to specific outputs; the
757 following command extract each channel of the audio stream (file 0, stream 0)
758 to the respective @var{OUTPUT_CH0} and @var{OUTPUT_CH1}:
760 ffmpeg -i INPUT -map_channel 0.0.0 OUTPUT_CH0 -map_channel 0.0.1 OUTPUT_CH1
763 The following example split the channels of a stereo input into streams:
766 ffmpeg -i stereo.wav -map 0:0 -map 0:0 -map_channel 0.0.0:0.0 -map_channel 0.0.1:0.1 -y out.ogg
769 Note that "-map_channel" is currently limited to the scope of one input for
770 each output; you can't for example use it to pick multiple input audio files
771 and mix them into one single output.
773 @item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}] (@emph{output,per-metadata})
774 Set metadata information of the next output file from @var{infile}. Note that
775 those are file indices (zero-based), not filenames.
776 Optional @var{metadata_type} parameters specify, which metadata to copy - (g)lobal
777 (i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or
778 per-(p)rogram. All metadata specifiers other than global must be followed by the
779 stream/chapter/program index. If metadata specifier is omitted, it defaults to
782 By default, global metadata is copied from the first input file,
783 per-stream and per-chapter metadata is copied along with streams/chapters. These
784 default mappings are disabled by creating any mapping of the relevant type. A negative
785 file index can be used to create a dummy mapping that just disables automatic copying.
787 For example to copy metadata from the first stream of the input file to global metadata
790 ffmpeg -i in.ogg -map_metadata 0:s:0 out.mp3
792 @item -map_chapters @var{input_file_index} (@emph{output})
793 Copy chapters from input file with index @var{input_file_index} to the next
794 output file. If no chapter mapping is specified, then chapters are copied from
795 the first input file with at least one chapter. Use a negative file index to
796 disable any chapter copying.
797 @item -debug @var{category}
798 Print specific debug info.
799 @var{category} is a number or a string containing one of the following values:
803 picture buffer allocations
811 memory management control operations (H.264)
818 per-block quantization parameter (QP)
826 visualize block types
828 visualize quantization parameter (QP), lower QP are tinted greener
830 @item -benchmark (@emph{global})
831 Show benchmarking information at the end of an encode.
832 Shows CPU time used and maximum memory consumption.
833 Maximum memory consumption is not supported on all systems,
834 it will usually display as 0 if not supported.
835 @item -timelimit @var{duration} (@emph{global})
836 Exit after ffmpeg has been running for @var{duration} seconds.
837 @item -dump (@emph{global})
838 Dump each input packet to stderr.
839 @item -hex (@emph{global})
840 When dumping packets, also dump the payload.
842 Set RTP payload size in bytes.
843 @item -re (@emph{input})
844 Read input at native frame rate. Mainly used to simulate a grab device.
846 Loop over the input stream. Currently it works only for image
847 streams. This option is used for automatic FFserver testing.
848 This option is deprecated, use -loop 1.
849 @item -loop_output @var{number_of_times}
850 Repeatedly loop output for formats that support looping such as animated GIF
851 (0 will loop the output infinitely).
852 This option is deprecated, use -loop.
853 @item -threads @var{count}
855 @item -vsync @var{parameter}
860 Each frame is passed with its timestamp from the demuxer to the muxer.
862 Frames will be duplicated and dropped to achieve exactly the requested
865 Frames are passed through with their timestamp or dropped so as to
866 prevent 2 frames from having the same timestamp.
868 Chooses between 1 and 2 depending on muxer capabilities. This is the
872 With -map you can select from which stream the timestamps should be
873 taken. You can leave either video or audio unchanged and sync the
874 remaining stream(s) to the unchanged one.
876 @item -async @var{samples_per_second}
877 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
878 the parameter is the maximum samples per second by which the audio is changed.
879 -async 1 is a special case where only the start of the audio stream is corrected
880 without any later correction.
882 Copy timestamps from input to output.
884 Copy input stream time base from input to output when stream copying.
886 Finish encoding when the shortest input stream ends.
887 @item -dts_delta_threshold
888 Timestamp discontinuity delta threshold.
889 @item -muxdelay @var{seconds} (@emph{input})
890 Set the maximum demux-decode delay.
891 @item -muxpreload @var{seconds} (@emph{input})
892 Set the initial demux-decode delay.
893 @item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
894 Assign a new stream-id value to an output stream. This option should be
895 specified prior to the output filename to which it applies.
896 For the situation where multiple output files exist, a streamid
897 may be reassigned to a different value.
899 For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
900 an output mpegts file:
902 ffmpeg -i infile -streamid 0:33 -streamid 1:36 out.ts
905 @item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
906 Set bitstream filters for matching streams. @var{bistream_filters} is
907 a comma-separated list of bitstream filters. Use the @code{-bsfs} option
908 to get the list of bitstream filters.
910 ffmpeg -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264
913 ffmpeg -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt
916 @item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{per-stream})
917 Force a tag/fourcc for matching streams.
920 @section Preset files
921 A preset file contains a sequence of @var{option}=@var{value} pairs,
922 one for each line, specifying a sequence of options which would be
923 awkward to specify on the command line. Lines starting with the hash
924 ('#') character are ignored and are used to provide comments. Check
925 the @file{presets} directory in the FFmpeg source tree for examples.
927 Preset files are specified with the @code{vpre}, @code{apre},
928 @code{spre}, and @code{fpre} options. The @code{fpre} option takes the
929 filename of the preset instead of a preset name as input and can be
930 used for any kind of codec. For the @code{vpre}, @code{apre}, and
931 @code{spre} options, the options specified in a preset file are
932 applied to the currently selected codec of the same type as the preset
935 The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
936 preset options identifies the preset file to use according to the
939 First ffmpeg searches for a file named @var{arg}.ffpreset in the
940 directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
941 the datadir defined at configuration time (usually @file{PREFIX/share/ffmpeg})
942 or in a @file{ffpresets} folder along the executable on win32,
943 in that order. For example, if the argument is @code{libx264-max}, it will
944 search for the file @file{libx264-max.ffpreset}.
946 If no such file is found, then ffmpeg will search for a file named
947 @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
948 directories, where @var{codec_name} is the name of the codec to which
949 the preset file options will be applied. For example, if you select
950 the video codec with @code{-vcodec libx264} and use @code{-vpre max},
951 then it will search for the file @file{libx264-max.ffpreset}.
959 For streaming at very low bitrate application, use a low frame rate
960 and a small GOP size. This is especially true for RealVideo where
961 the Linux player does not seem to be very fast, so it can miss
962 frames. An example is:
965 ffmpeg -g 3 -r 3 -t 10 -b:v 50k -s qcif -f rv10 /tmp/b.rm
969 The parameter 'q' which is displayed while encoding is the current
970 quantizer. The value 1 indicates that a very good quality could
971 be achieved. The value 31 indicates the worst quality. If q=31 appears
972 too often, it means that the encoder cannot compress enough to meet
973 your bitrate. You must either increase the bitrate, decrease the
974 frame rate or decrease the frame size.
977 If your computer is not fast enough, you can speed up the
978 compression at the expense of the compression ratio. You can use
979 '-me zero' to speed up motion estimation, and '-intra' to disable
980 motion estimation completely (you have only I-frames, which means it
981 is about as good as JPEG compression).
984 To have very low audio bitrates, reduce the sampling frequency
985 (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
988 To have a constant quality (but a variable bitrate), use the option
989 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
996 @c man begin EXAMPLES
998 @section Video and Audio grabbing
1000 If you specify the input format and device then ffmpeg can grab video
1004 ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
1007 Or with an ALSA audio source (mono input, card id 1) instead of OSS:
1009 ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -i /dev/video0 /tmp/out.mpg
1012 Note that you must activate the right video source and channel before
1013 launching ffmpeg with any TV viewer such as
1014 @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
1015 have to set the audio recording levels correctly with a
1018 @section X11 grabbing
1020 Grab the X11 display with ffmpeg via
1023 ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg
1026 0.0 is display.screen number of your X11 server, same as
1027 the DISPLAY environment variable.
1030 ffmpeg -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg
1033 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
1034 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
1036 @section Video and Audio file format conversion
1038 Any supported file format and protocol can serve as input to ffmpeg:
1043 You can use YUV files as input:
1046 ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
1049 It will use the files:
1051 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
1052 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
1055 The Y files use twice the resolution of the U and V files. They are
1056 raw files, without header. They can be generated by all decent video
1057 decoders. You must specify the size of the image with the @option{-s} option
1058 if ffmpeg cannot guess it.
1061 You can input from a raw YUV420P file:
1064 ffmpeg -i /tmp/test.yuv /tmp/out.avi
1067 test.yuv is a file containing raw YUV planar data. Each frame is composed
1068 of the Y plane followed by the U and V planes at half vertical and
1069 horizontal resolution.
1072 You can output to a raw YUV420P file:
1075 ffmpeg -i mydivx.avi hugefile.yuv
1079 You can set several input files and output files:
1082 ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
1085 Converts the audio file a.wav and the raw YUV video file a.yuv
1089 You can also do audio and video conversions at the same time:
1092 ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
1095 Converts a.wav to MPEG audio at 22050 Hz sample rate.
1098 You can encode to several formats at the same time and define a
1099 mapping from input stream to output streams:
1102 ffmpeg -i /tmp/a.wav -map 0:a -b:a 64k /tmp/a.mp2 -map 0:a -b:a 128k /tmp/b.mp2
1105 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
1106 file:index' specifies which input stream is used for each output
1107 stream, in the order of the definition of output streams.
1110 You can transcode decrypted VOBs:
1113 ffmpeg -i snatch_1.vob -f avi -c:v mpeg4 -b:v 800k -g 300 -bf 2 -c:a libmp3lame -b:a 128k snatch.avi
1116 This is a typical DVD ripping example; the input is a VOB file, the
1117 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
1118 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
1119 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
1120 input video. Furthermore, the audio stream is MP3-encoded so you need
1121 to enable LAME support by passing @code{--enable-libmp3lame} to configure.
1122 The mapping is particularly useful for DVD transcoding
1123 to get the desired audio language.
1125 NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
1128 You can extract images from a video, or create a video from many images:
1130 For extracting images from a video:
1132 ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
1135 This will extract one video frame per second from the video and will
1136 output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
1137 etc. Images will be rescaled to fit the new WxH values.
1139 If you want to extract just a limited number of frames, you can use the
1140 above command in combination with the -vframes or -t option, or in
1141 combination with -ss to start extracting from a certain point in time.
1143 For creating a video from many images:
1145 ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi
1148 The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
1149 composed of three digits padded with zeroes to express the sequence
1150 number. It is the same syntax supported by the C printf function, but
1151 only formats accepting a normal integer are suitable.
1154 You can put many streams of the same type in the output:
1157 ffmpeg -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut
1160 The resulting output file @file{test12.avi} will contain first four streams from
1161 the input file in reverse order.
1167 @include decoders.texi
1168 @include encoders.texi
1169 @include demuxers.texi
1170 @include muxers.texi
1171 @include indevs.texi
1172 @include outdevs.texi
1173 @include protocols.texi
1174 @include bitstream_filters.texi
1175 @include filters.texi
1176 @include metadata.texi
1181 @settitle ffmpeg video converter
1183 @c man begin SEEALSO
1184 ffplay(1), ffprobe(1), ffserver(1) and the FFmpeg HTML documentation
1187 @c man begin AUTHORS