1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} functions defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of two forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows one to name a link and associate it to a filter output
176 or input pad. The preceding labels @var{in_link_1}
177 ... @var{in_link_N}, are associated to the filter input pads,
178 the following labels @var{out_link_1} ... @var{out_link_M}, are
179 associated to the output pads.
181 When two link labels with the same name are found in the
182 filtergraph, a link between the corresponding input and output pad is
185 If an output pad is not labelled, it is linked by default to the first
186 unlabelled input pad of the next filter in the filterchain.
187 For example in the filterchain
189 nullsrc, split[L1], [L2]overlay, nullsink
191 the split filter instance has two output pads, and the overlay filter
192 instance two input pads. The first output pad of split is labelled
193 "L1", the first input pad of overlay is labelled "L2", and the second
194 output pad of split is linked to the second input pad of overlay,
195 which are both unlabelled.
197 In a complete filterchain all the unlabelled filter input and output
198 pads must be connected. A filtergraph is considered valid if all the
199 filter input and output pads of all the filterchains are connected.
201 Libavfilter will automatically insert @ref{scale} filters where format
202 conversion is required. It is possible to specify swscale flags
203 for those automatically inserted scalers by prepending
204 @code{sws_flags=@var{flags};}
205 to the filtergraph description.
207 Here is a BNF description of the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
287 Additionally, these filters support an @option{enable} command that can be used
288 to re-define the expression.
290 Like any other filtering option, the @option{enable} option follows the same
293 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
294 minutes, and a @ref{curves} filter starting at 3 seconds:
296 smartblur = enable='between(t,10,3*60)',
297 curves = enable='gte(t,3)' : preset=cross_process
300 @c man end FILTERGRAPH DESCRIPTION
302 @chapter Audio Filters
303 @c man begin AUDIO FILTERS
305 When you configure your FFmpeg build, you can disable any of the
306 existing filters using @code{--disable-filters}.
307 The configure output will show the audio filters included in your
310 Below is a description of the currently available audio filters.
314 Convert the input audio format to the specified formats.
316 @emph{This filter is deprecated. Use @ref{aformat} instead.}
318 The filter accepts a string of the form:
319 "@var{sample_format}:@var{channel_layout}".
321 @var{sample_format} specifies the sample format, and can be a string or the
322 corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
323 suffix for a planar sample format.
325 @var{channel_layout} specifies the channel layout, and can be a string
326 or the corresponding number value defined in @file{libavutil/channel_layout.h}.
328 The special parameter "auto", signifies that the filter will
329 automatically select the output format depending on the output filter.
335 Convert input to float, planar, stereo:
341 Convert input to unsigned 8-bit, automatically select out channel layout:
349 Delay one or more audio channels.
351 Samples in delayed channel are filled with silence.
353 The filter accepts the following option:
357 Set list of delays in milliseconds for each channel separated by '|'.
358 At least one delay greater than 0 should be provided.
359 Unused delays will be silently ignored. If number of given delays is
360 smaller than number of channels all remaining channels will not be delayed.
367 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
368 the second channel (and any other channels that may be present) unchanged.
376 Apply echoing to the input audio.
378 Echoes are reflected sound and can occur naturally amongst mountains
379 (and sometimes large buildings) when talking or shouting; digital echo
380 effects emulate this behaviour and are often used to help fill out the
381 sound of a single instrument or vocal. The time difference between the
382 original signal and the reflection is the @code{delay}, and the
383 loudness of the reflected signal is the @code{decay}.
384 Multiple echoes can have different delays and decays.
386 A description of the accepted parameters follows.
390 Set input gain of reflected signal. Default is @code{0.6}.
393 Set output gain of reflected signal. Default is @code{0.3}.
396 Set list of time intervals in milliseconds between original signal and reflections
397 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
398 Default is @code{1000}.
401 Set list of loudnesses of reflected signals separated by '|'.
402 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
403 Default is @code{0.5}.
410 Make it sound as if there are twice as many instruments as are actually playing:
412 aecho=0.8:0.88:60:0.4
416 If delay is very short, then it sound like a (metallic) robot playing music:
422 A longer delay will sound like an open air concert in the mountains:
424 aecho=0.8:0.9:1000:0.3
428 Same as above but with one more mountain:
430 aecho=0.8:0.9:1000|1800:0.3|0.25
436 Modify an audio signal according to the specified expressions.
438 This filter accepts one or more expressions (one for each channel),
439 which are evaluated and used to modify a corresponding audio signal.
441 It accepts the following parameters:
445 Set the '|'-separated expressions list for each separate channel. If
446 the number of input channels is greater than the number of
447 expressions, the last specified expression is used for the remaining
450 @item channel_layout, c
451 Set output channel layout. If not specified, the channel layout is
452 specified by the number of expressions. If set to @samp{same}, it will
453 use by default the same input channel layout.
456 Each expression in @var{exprs} can contain the following constants and functions:
460 channel number of the current expression
463 number of the evaluated sample, starting from 0
469 time of the evaluated sample expressed in seconds
472 @item nb_out_channels
473 input and output number of channels
476 the value of input channel with number @var{CH}
479 Note: this filter is slow. For faster processing you should use a
488 aeval=val(ch)/2:c=same
492 Invert phase of the second channel:
500 Apply fade-in/out effect to input audio.
502 A description of the accepted parameters follows.
506 Specify the effect type, can be either @code{in} for fade-in, or
507 @code{out} for a fade-out effect. Default is @code{in}.
509 @item start_sample, ss
510 Specify the number of the start sample for starting to apply the fade
511 effect. Default is 0.
514 Specify the number of samples for which the fade effect has to last. At
515 the end of the fade-in effect the output audio will have the same
516 volume as the input audio, at the end of the fade-out transition
517 the output audio will be silence. Default is 44100.
520 Specify time for starting to apply the fade effect. Default is 0.
521 The accepted syntax is:
523 [-]HH[:MM[:SS[.m...]]]
526 See also the function @code{av_parse_time()}.
527 If set this option is used instead of @var{start_sample} one.
530 Specify the duration for which the fade effect has to last. Default is 0.
531 The accepted syntax is:
533 [-]HH[:MM[:SS[.m...]]]
536 See also the function @code{av_parse_time()}.
537 At the end of the fade-in effect the output audio will have the same
538 volume as the input audio, at the end of the fade-out transition
539 the output audio will be silence.
540 If set this option is used instead of @var{nb_samples} one.
543 Set curve for fade transition.
545 It accepts the following values:
548 select triangular, linear slope (default)
550 select quarter of sine wave
552 select half of sine wave
554 select exponential sine wave
558 select inverted parabola
574 Fade in first 15 seconds of audio:
580 Fade out last 25 seconds of a 900 seconds audio:
582 afade=t=out:st=875:d=25
589 Set output format constraints for the input audio. The framework will
590 negotiate the most appropriate format to minimize conversions.
592 It accepts the following parameters:
596 A '|'-separated list of requested sample formats.
599 A '|'-separated list of requested sample rates.
601 @item channel_layouts
602 A '|'-separated list of requested channel layouts.
604 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
605 for the required syntax.
608 If a parameter is omitted, all values are allowed.
610 Force the output to either unsigned 8-bit or signed 16-bit stereo
612 aformat=sample_fmts=u8|s16:channel_layouts=stereo
617 Apply a two-pole all-pass filter with central frequency (in Hz)
618 @var{frequency}, and filter-width @var{width}.
619 An all-pass filter changes the audio's frequency to phase relationship
620 without changing its frequency to amplitude relationship.
622 The filter accepts the following options:
629 Set method to specify band-width of filter.
642 Specify the band-width of a filter in width_type units.
647 Merge two or more audio streams into a single multi-channel stream.
649 The filter accepts the following options:
654 Set the number of inputs. Default is 2.
658 If the channel layouts of the inputs are disjoint, and therefore compatible,
659 the channel layout of the output will be set accordingly and the channels
660 will be reordered as necessary. If the channel layouts of the inputs are not
661 disjoint, the output will have all the channels of the first input then all
662 the channels of the second input, in that order, and the channel layout of
663 the output will be the default value corresponding to the total number of
666 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
667 is FC+BL+BR, then the output will be in 5.1, with the channels in the
668 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
669 first input, b1 is the first channel of the second input).
671 On the other hand, if both input are in stereo, the output channels will be
672 in the default order: a1, a2, b1, b2, and the channel layout will be
673 arbitrarily set to 4.0, which may or may not be the expected value.
675 All inputs must have the same sample rate, and format.
677 If inputs do not have the same duration, the output will stop with the
684 Merge two mono files into a stereo stream:
686 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
690 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
692 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
698 Mixes multiple audio inputs into a single output.
702 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
704 will mix 3 input audio streams to a single output with the same duration as the
705 first input and a dropout transition time of 3 seconds.
707 It accepts the following parameters:
711 The number of inputs. If unspecified, it defaults to 2.
714 How to determine the end-of-stream.
718 The duration of the longest input. (default)
721 The duration of the shortest input.
724 The duration of the first input.
728 @item dropout_transition
729 The transition time, in seconds, for volume renormalization when an input
730 stream ends. The default value is 2 seconds.
736 Pass the audio source unchanged to the output.
740 Pad the end of a audio stream with silence, this can be used together with
741 -shortest to extend audio streams to the same length as the video stream.
744 Add a phasing effect to the input audio.
746 A phaser filter creates series of peaks and troughs in the frequency spectrum.
747 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
749 A description of the accepted parameters follows.
753 Set input gain. Default is 0.4.
756 Set output gain. Default is 0.74
759 Set delay in milliseconds. Default is 3.0.
762 Set decay. Default is 0.4.
765 Set modulation speed in Hz. Default is 0.5.
768 Set modulation type. Default is triangular.
770 It accepts the following values:
780 Resample the input audio to the specified parameters, using the
781 libswresample library. If none are specified then the filter will
782 automatically convert between its input and output.
784 This filter is also able to stretch/squeeze the audio data to make it match
785 the timestamps or to inject silence / cut out audio to make it match the
786 timestamps, do a combination of both or do neither.
788 The filter accepts the syntax
789 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
790 expresses a sample rate and @var{resampler_options} is a list of
791 @var{key}=@var{value} pairs, separated by ":". See the
792 ffmpeg-resampler manual for the complete list of supported options.
798 Resample the input audio to 44100Hz:
804 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
805 samples per second compensation:
811 @section asetnsamples
813 Set the number of samples per each output audio frame.
815 The last output packet may contain a different number of samples, as
816 the filter will flush all the remaining samples when the input audio
819 The filter accepts the following options:
823 @item nb_out_samples, n
824 Set the number of frames per each output audio frame. The number is
825 intended as the number of samples @emph{per each channel}.
826 Default value is 1024.
829 If set to 1, the filter will pad the last audio frame with zeroes, so
830 that the last frame will contain the same number of samples as the
831 previous ones. Default value is 1.
834 For example, to set the number of per-frame samples to 1234 and
835 disable padding for the last frame, use:
837 asetnsamples=n=1234:p=0
842 Set the sample rate without altering the PCM data.
843 This will result in a change of speed and pitch.
845 The filter accepts the following options:
849 Set the output sample rate. Default is 44100 Hz.
854 Show a line containing various information for each input audio frame.
855 The input audio is not modified.
857 The shown line contains a sequence of key/value pairs of the form
858 @var{key}:@var{value}.
860 It accepts the following parameters:
864 The (sequential) number of the input frame, starting from 0.
867 The presentation timestamp of the input frame, in time base units; the time base
868 depends on the filter input pad, and is usually 1/@var{sample_rate}.
871 The presentation timestamp of the input frame in seconds.
874 position of the frame in the input stream, -1 if this information in
875 unavailable and/or meaningless (for example in case of synthetic audio)
884 The sample rate for the audio frame.
887 The number of samples (per channel) in the frame.
890 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
891 audio, the data is treated as if all the planes were concatenated.
893 @item plane_checksums
894 A list of Adler-32 checksums for each data plane.
899 Display time domain statistical information about the audio channels.
900 Statistics are calculated and displayed for each audio channel and,
901 where applicable, an overall figure is also given.
903 It accepts the following option:
906 Short window length in seconds, used for peak and trough RMS measurement.
907 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
910 A description of each shown parameter follows:
914 Mean amplitude displacement from zero.
917 Minimal sample level.
920 Maximal sample level.
924 Standard peak and RMS level measured in dBFS.
928 Peak and trough values for RMS level measured over a short window.
931 Standard ratio of peak to RMS level (note: not in dB).
934 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
935 (i.e. either @var{Min level} or @var{Max level}).
938 Number of occasions (not the number of samples) that the signal attained either
939 @var{Min level} or @var{Max level}.
944 Forward two audio streams and control the order the buffers are forwarded.
946 The filter accepts the following options:
950 Set the expression deciding which stream should be
951 forwarded next: if the result is negative, the first stream is forwarded; if
952 the result is positive or zero, the second stream is forwarded. It can use
953 the following variables:
957 number of buffers forwarded so far on each stream
959 number of samples forwarded so far on each stream
961 current timestamp of each stream
964 The default value is @code{t1-t2}, which means to always forward the stream
965 that has a smaller timestamp.
970 Stress-test @code{amerge} by randomly sending buffers on the wrong
971 input, while avoiding too much of a desynchronization:
973 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
974 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
980 Synchronize audio data with timestamps by squeezing/stretching it and/or
981 dropping samples/adding silence when needed.
983 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
985 It accepts the following parameters:
989 Enable stretching/squeezing the data to make it match the timestamps. Disabled
990 by default. When disabled, time gaps are covered with silence.
993 The minimum difference between timestamps and audio data (in seconds) to trigger
994 adding/dropping samples. The default value is 0.1. If you get an imperfect
995 sync with this filter, try setting this parameter to 0.
998 The maximum compensation in samples per second. Only relevant with compensate=1.
999 The default value is 500.
1002 Assume that the first PTS should be this value. The time base is 1 / sample
1003 rate. This allows for padding/trimming at the start of the stream. By default,
1004 no assumption is made about the first frame's expected PTS, so no padding or
1005 trimming is done. For example, this could be set to 0 to pad the beginning with
1006 silence if an audio stream starts after the video stream or to trim any samples
1007 with a negative PTS due to encoder delay.
1015 The filter accepts exactly one parameter, the audio tempo. If not
1016 specified then the filter will assume nominal 1.0 tempo. Tempo must
1017 be in the [0.5, 2.0] range.
1019 @subsection Examples
1023 Slow down audio to 80% tempo:
1029 To speed up audio to 125% tempo:
1037 Trim the input so that the output contains one continuous subpart of the input.
1039 It accepts the following parameters:
1042 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1043 sample with the timestamp @var{start} will be the first sample in the output.
1046 Specify time of the first audio sample that will be dropped, i.e. the
1047 audio sample immediately preceding the one with the timestamp @var{end} will be
1048 the last sample in the output.
1051 Same as @var{start}, except this option sets the start timestamp in samples
1055 Same as @var{end}, except this option sets the end timestamp in samples instead
1059 The maximum duration of the output in seconds.
1062 The number of the first sample that should be output.
1065 The number of the first sample that should be dropped.
1068 @option{start}, @option{end}, @option{duration} are expressed as time
1069 duration specifications, check the "Time duration" section in the
1070 ffmpeg-utils manual.
1072 Note that the first two sets of the start/end options and the @option{duration}
1073 option look at the frame timestamp, while the _sample options simply count the
1074 samples that pass through the filter. So start/end_pts and start/end_sample will
1075 give different results when the timestamps are wrong, inexact or do not start at
1076 zero. Also note that this filter does not modify the timestamps. If you wish
1077 to have the output timestamps start at zero, insert the asetpts filter after the
1080 If multiple start or end options are set, this filter tries to be greedy and
1081 keep all samples that match at least one of the specified constraints. To keep
1082 only the part that matches all the constraints at once, chain multiple atrim
1085 The defaults are such that all the input is kept. So it is possible to set e.g.
1086 just the end values to keep everything before the specified time.
1091 Drop everything except the second minute of input:
1093 ffmpeg -i INPUT -af atrim=60:120
1097 Keep only the first 1000 samples:
1099 ffmpeg -i INPUT -af atrim=end_sample=1000
1106 Apply a two-pole Butterworth band-pass filter with central
1107 frequency @var{frequency}, and (3dB-point) band-width width.
1108 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1109 instead of the default: constant 0dB peak gain.
1110 The filter roll off at 6dB per octave (20dB per decade).
1112 The filter accepts the following options:
1116 Set the filter's central frequency. Default is @code{3000}.
1119 Constant skirt gain if set to 1. Defaults to 0.
1122 Set method to specify band-width of filter.
1135 Specify the band-width of a filter in width_type units.
1140 Apply a two-pole Butterworth band-reject filter with central
1141 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1142 The filter roll off at 6dB per octave (20dB per decade).
1144 The filter accepts the following options:
1148 Set the filter's central frequency. Default is @code{3000}.
1151 Set method to specify band-width of filter.
1164 Specify the band-width of a filter in width_type units.
1169 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1170 shelving filter with a response similar to that of a standard
1171 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1173 The filter accepts the following options:
1177 Give the gain at 0 Hz. Its useful range is about -20
1178 (for a large cut) to +20 (for a large boost).
1179 Beware of clipping when using a positive gain.
1182 Set the filter's central frequency and so can be used
1183 to extend or reduce the frequency range to be boosted or cut.
1184 The default value is @code{100} Hz.
1187 Set method to specify band-width of filter.
1200 Determine how steep is the filter's shelf transition.
1205 Apply a biquad IIR filter with the given coefficients.
1206 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1207 are the numerator and denominator coefficients respectively.
1210 Bauer stereo to binaural transformation, which improves headphone listening of
1211 stereo audio records.
1213 It accepts the following parameters:
1217 Pre-defined crossfeed level.
1221 Default level (fcut=700, feed=50).
1224 Chu Moy circuit (fcut=700, feed=60).
1227 Jan Meier circuit (fcut=650, feed=95).
1232 Cut frequency (in Hz).
1241 Remap input channels to new locations.
1243 It accepts the following parameters:
1245 @item channel_layout
1246 The channel layout of the output stream.
1249 Map channels from input to output. The argument is a '|'-separated list of
1250 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1251 @var{in_channel} form. @var{in_channel} can be either the name of the input
1252 channel (e.g. FL for front left) or its index in the input channel layout.
1253 @var{out_channel} is the name of the output channel or its index in the output
1254 channel layout. If @var{out_channel} is not given then it is implicitly an
1255 index, starting with zero and increasing by one for each mapping.
1258 If no mapping is present, the filter will implicitly map input channels to
1259 output channels, preserving indices.
1261 For example, assuming a 5.1+downmix input MOV file,
1263 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1265 will create an output WAV file tagged as stereo from the downmix channels of
1268 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1270 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1273 @section channelsplit
1275 Split each channel from an input audio stream into a separate output stream.
1277 It accepts the following parameters:
1279 @item channel_layout
1280 The channel layout of the input stream. The default is "stereo".
1283 For example, assuming a stereo input MP3 file,
1285 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1287 will create an output Matroska file with two audio streams, one containing only
1288 the left channel and the other the right channel.
1290 Split a 5.1 WAV file into per-channel files:
1292 ffmpeg -i in.wav -filter_complex
1293 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1294 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1295 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1300 Compress or expand the audio's dynamic range.
1302 It accepts the following parameters:
1308 A list of times in seconds for each channel over which the instantaneous level
1309 of the input signal is averaged to determine its volume. @var{attacks} refers to
1310 increase of volume and @var{decays} refers to decrease of volume. For most
1311 situations, the attack time (response to the audio getting louder) should be
1312 shorter than the decay time, because the human ear is more sensitive to sudden
1313 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1314 a typical value for decay is 0.8 seconds.
1317 A list of points for the transfer function, specified in dB relative to the
1318 maximum possible signal amplitude. Each key points list must be defined using
1319 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1320 @code{x0/y0 x1/y1 x2/y2 ....}
1322 The input values must be in strictly increasing order but the transfer function
1323 does not have to be monotonically rising. The point @code{0/0} is assumed but
1324 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1325 function are @code{-70/-70|-60/-20}.
1328 Set the curve radius in dB for all joints. It defaults to 0.01.
1331 Set the additional gain in dB to be applied at all points on the transfer
1332 function. This allows for easy adjustment of the overall gain.
1336 Set an initial volume, in dB, to be assumed for each channel when filtering
1337 starts. This permits the user to supply a nominal level initially, so that, for
1338 example, a very large gain is not applied to initial signal levels before the
1339 companding has begun to operate. A typical value for audio which is initially
1340 quiet is -90 dB. It defaults to 0.
1343 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1344 delayed before being fed to the volume adjuster. Specifying a delay
1345 approximately equal to the attack/decay times allows the filter to effectively
1346 operate in predictive rather than reactive mode. It defaults to 0.
1350 @subsection Examples
1354 Make music with both quiet and loud passages suitable for listening to in a
1357 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1361 A noise gate for when the noise is at a lower level than the signal:
1363 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1367 Here is another noise gate, this time for when the noise is at a higher level
1368 than the signal (making it, in some ways, similar to squelch):
1370 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1376 Make audio easier to listen to on headphones.
1378 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1379 so that when listened to on headphones the stereo image is moved from
1380 inside your head (standard for headphones) to outside and in front of
1381 the listener (standard for speakers).
1387 Apply a two-pole peaking equalisation (EQ) filter. With this
1388 filter, the signal-level at and around a selected frequency can
1389 be increased or decreased, whilst (unlike bandpass and bandreject
1390 filters) that at all other frequencies is unchanged.
1392 In order to produce complex equalisation curves, this filter can
1393 be given several times, each with a different central frequency.
1395 The filter accepts the following options:
1399 Set the filter's central frequency in Hz.
1402 Set method to specify band-width of filter.
1415 Specify the band-width of a filter in width_type units.
1418 Set the required gain or attenuation in dB.
1419 Beware of clipping when using a positive gain.
1422 @subsection Examples
1425 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1427 equalizer=f=1000:width_type=h:width=200:g=-10
1431 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1433 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1439 Apply a high-pass filter with 3dB point frequency.
1440 The filter can be either single-pole, or double-pole (the default).
1441 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1443 The filter accepts the following options:
1447 Set frequency in Hz. Default is 3000.
1450 Set number of poles. Default is 2.
1453 Set method to specify band-width of filter.
1466 Specify the band-width of a filter in width_type units.
1467 Applies only to double-pole filter.
1468 The default is 0.707q and gives a Butterworth response.
1473 Join multiple input streams into one multi-channel stream.
1475 It accepts the following parameters:
1479 The number of input streams. It defaults to 2.
1481 @item channel_layout
1482 The desired output channel layout. It defaults to stereo.
1485 Map channels from inputs to output. The argument is a '|'-separated list of
1486 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1487 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1488 can be either the name of the input channel (e.g. FL for front left) or its
1489 index in the specified input stream. @var{out_channel} is the name of the output
1493 The filter will attempt to guess the mappings when they are not specified
1494 explicitly. It does so by first trying to find an unused matching input channel
1495 and if that fails it picks the first unused input channel.
1497 Join 3 inputs (with properly set channel layouts):
1499 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1502 Build a 5.1 output from 6 single-channel streams:
1504 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1505 'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
1511 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1513 To enable compilation of this filter you need to configure FFmpeg with
1514 @code{--enable-ladspa}.
1518 Specifies the name of LADSPA plugin library to load. If the environment
1519 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1520 each one of the directories specified by the colon separated list in
1521 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1522 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1523 @file{/usr/lib/ladspa/}.
1526 Specifies the plugin within the library. Some libraries contain only
1527 one plugin, but others contain many of them. If this is not set filter
1528 will list all available plugins within the specified library.
1531 Set the '|' separated list of controls which are zero or more floating point
1532 values that determine the behavior of the loaded plugin (for example delay,
1534 Controls need to be defined using the following syntax:
1535 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1536 @var{valuei} is the value set on the @var{i}-th control.
1537 If @option{controls} is set to @code{help}, all available controls and
1538 their valid ranges are printed.
1540 @item sample_rate, s
1541 Specify the sample rate, default to 44100. Only used if plugin have
1545 Set the number of samples per channel per each output frame, default
1546 is 1024. Only used if plugin have zero inputs.
1549 Set the minimum duration of the sourced audio. See the function
1550 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1551 section in the ffmpeg-utils manual.
1552 Note that the resulting duration may be greater than the specified duration,
1553 as the generated audio is always cut at the end of a complete frame.
1554 If not specified, or the expressed duration is negative, the audio is
1555 supposed to be generated forever.
1556 Only used if plugin have zero inputs.
1560 @subsection Examples
1564 List all available plugins within amp (LADSPA example plugin) library:
1570 List all available controls and their valid ranges for @code{vcf_notch}
1571 plugin from @code{VCF} library:
1573 ladspa=f=vcf:p=vcf_notch:c=help
1577 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1580 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1584 Add reverberation to the audio using TAP-plugins
1585 (Tom's Audio Processing plugins):
1587 ladspa=file=tap_reverb:tap_reverb
1591 Generate white noise, with 0.2 amplitude:
1593 ladspa=file=cmt:noise_source_white:c=c0=.2
1597 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1598 @code{C* Audio Plugin Suite} (CAPS) library:
1600 ladspa=file=caps:Click:c=c1=20'
1604 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1606 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1610 @subsection Commands
1612 This filter supports the following commands:
1615 Modify the @var{N}-th control value.
1617 If the specified value is not valid, it is ignored and prior one is kept.
1622 Apply a low-pass filter with 3dB point frequency.
1623 The filter can be either single-pole or double-pole (the default).
1624 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1626 The filter accepts the following options:
1630 Set frequency in Hz. Default is 500.
1633 Set number of poles. Default is 2.
1636 Set method to specify band-width of filter.
1649 Specify the band-width of a filter in width_type units.
1650 Applies only to double-pole filter.
1651 The default is 0.707q and gives a Butterworth response.
1656 Mix channels with specific gain levels. The filter accepts the output
1657 channel layout followed by a set of channels definitions.
1659 This filter is also designed to remap efficiently the channels of an audio
1662 The filter accepts parameters of the form:
1663 "@var{l}:@var{outdef}:@var{outdef}:..."
1667 output channel layout or number of channels
1670 output channel specification, of the form:
1671 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1674 output channel to define, either a channel name (FL, FR, etc.) or a channel
1675 number (c0, c1, etc.)
1678 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1681 input channel to use, see out_name for details; it is not possible to mix
1682 named and numbered input channels
1685 If the `=' in a channel specification is replaced by `<', then the gains for
1686 that specification will be renormalized so that the total is 1, thus
1687 avoiding clipping noise.
1689 @subsection Mixing examples
1691 For example, if you want to down-mix from stereo to mono, but with a bigger
1692 factor for the left channel:
1694 pan=1:c0=0.9*c0+0.1*c1
1697 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1698 7-channels surround:
1700 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1703 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1704 that should be preferred (see "-ac" option) unless you have very specific
1707 @subsection Remapping examples
1709 The channel remapping will be effective if, and only if:
1712 @item gain coefficients are zeroes or ones,
1713 @item only one input per channel output,
1716 If all these conditions are satisfied, the filter will notify the user ("Pure
1717 channel mapping detected"), and use an optimized and lossless method to do the
1720 For example, if you have a 5.1 source and want a stereo audio stream by
1721 dropping the extra channels:
1723 pan="stereo: c0=FL : c1=FR"
1726 Given the same source, you can also switch front left and front right channels
1727 and keep the input channel layout:
1729 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1732 If the input is a stereo audio stream, you can mute the front left channel (and
1733 still keep the stereo channel layout) with:
1738 Still with a stereo audio stream input, you can copy the right channel in both
1739 front left and right:
1741 pan="stereo: c0=FR : c1=FR"
1746 ReplayGain scanner filter. This filter takes an audio stream as an input and
1747 outputs it unchanged.
1748 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1752 Convert the audio sample format, sample rate and channel layout. It is
1753 not meant to be used directly.
1755 @section silencedetect
1757 Detect silence in an audio stream.
1759 This filter logs a message when it detects that the input audio volume is less
1760 or equal to a noise tolerance value for a duration greater or equal to the
1761 minimum detected noise duration.
1763 The printed times and duration are expressed in seconds.
1765 The filter accepts the following options:
1769 Set silence duration until notification (default is 2 seconds).
1772 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1773 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1776 @subsection Examples
1780 Detect 5 seconds of silence with -50dB noise tolerance:
1782 silencedetect=n=-50dB:d=5
1786 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1787 tolerance in @file{silence.mp3}:
1789 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1795 Boost or cut treble (upper) frequencies of the audio using a two-pole
1796 shelving filter with a response similar to that of a standard
1797 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1799 The filter accepts the following options:
1803 Give the gain at whichever is the lower of ~22 kHz and the
1804 Nyquist frequency. Its useful range is about -20 (for a large cut)
1805 to +20 (for a large boost). Beware of clipping when using a positive gain.
1808 Set the filter's central frequency and so can be used
1809 to extend or reduce the frequency range to be boosted or cut.
1810 The default value is @code{3000} Hz.
1813 Set method to specify band-width of filter.
1826 Determine how steep is the filter's shelf transition.
1831 Adjust the input audio volume.
1833 It accepts the following parameters:
1837 Set audio volume expression.
1839 Output values are clipped to the maximum value.
1841 The output audio volume is given by the relation:
1843 @var{output_volume} = @var{volume} * @var{input_volume}
1846 The default value for @var{volume} is "1.0".
1849 This parameter represents the mathematical precision.
1851 It determines which input sample formats will be allowed, which affects the
1852 precision of the volume scaling.
1856 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1858 32-bit floating-point; this limits input sample format to FLT. (default)
1860 64-bit floating-point; this limits input sample format to DBL.
1864 Choose the behaviour on encountering ReplayGain side data in input frames.
1868 Remove ReplayGain side data, ignoring its contents (the default).
1871 Ignore ReplayGain side data, but leave it in the frame.
1874 Prefer the track gain, if present.
1877 Prefer the album gain, if present.
1880 @item replaygain_preamp
1881 Pre-amplification gain in dB to apply to the selected replaygain gain.
1883 Default value for @var{replaygain_preamp} is 0.0.
1886 Set when the volume expression is evaluated.
1888 It accepts the following values:
1891 only evaluate expression once during the filter initialization, or
1892 when the @samp{volume} command is sent
1895 evaluate expression for each incoming frame
1898 Default value is @samp{once}.
1901 The volume expression can contain the following parameters.
1905 frame number (starting at zero)
1908 @item nb_consumed_samples
1909 number of samples consumed by the filter
1911 number of samples in the current frame
1913 original frame position in the file
1919 PTS at start of stream
1921 time at start of stream
1927 last set volume value
1930 Note that when @option{eval} is set to @samp{once} only the
1931 @var{sample_rate} and @var{tb} variables are available, all other
1932 variables will evaluate to NAN.
1934 @subsection Commands
1936 This filter supports the following commands:
1939 Modify the volume expression.
1940 The command accepts the same syntax of the corresponding option.
1942 If the specified expression is not valid, it is kept at its current
1944 @item replaygain_noclip
1945 Prevent clipping by limiting the gain applied.
1947 Default value for @var{replaygain_noclip} is 1.
1951 @subsection Examples
1955 Halve the input audio volume:
1959 volume=volume=-6.0206dB
1962 In all the above example the named key for @option{volume} can be
1963 omitted, for example like in:
1969 Increase input audio power by 6 decibels using fixed-point precision:
1971 volume=volume=6dB:precision=fixed
1975 Fade volume after time 10 with an annihilation period of 5 seconds:
1977 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
1981 @section volumedetect
1983 Detect the volume of the input video.
1985 The filter has no parameters. The input is not modified. Statistics about
1986 the volume will be printed in the log when the input stream end is reached.
1988 In particular it will show the mean volume (root mean square), maximum
1989 volume (on a per-sample basis), and the beginning of a histogram of the
1990 registered volume values (from the maximum value to a cumulated 1/1000 of
1993 All volumes are in decibels relative to the maximum PCM value.
1995 @subsection Examples
1997 Here is an excerpt of the output:
1999 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2000 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2001 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2002 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2003 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2004 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2005 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2006 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2007 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2013 The mean square energy is approximately -27 dB, or 10^-2.7.
2015 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2017 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2020 In other words, raising the volume by +4 dB does not cause any clipping,
2021 raising it by +5 dB causes clipping for 6 samples, etc.
2023 @c man end AUDIO FILTERS
2025 @chapter Audio Sources
2026 @c man begin AUDIO SOURCES
2028 Below is a description of the currently available audio sources.
2032 Buffer audio frames, and make them available to the filter chain.
2034 This source is mainly intended for a programmatic use, in particular
2035 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2037 It accepts the following parameters:
2041 The timebase which will be used for timestamps of submitted frames. It must be
2042 either a floating-point number or in @var{numerator}/@var{denominator} form.
2045 The sample rate of the incoming audio buffers.
2048 The sample format of the incoming audio buffers.
2049 Either a sample format name or its corresponging integer representation from
2050 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2052 @item channel_layout
2053 The channel layout of the incoming audio buffers.
2054 Either a channel layout name from channel_layout_map in
2055 @file{libavutil/channel_layout.c} or its corresponding integer representation
2056 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2059 The number of channels of the incoming audio buffers.
2060 If both @var{channels} and @var{channel_layout} are specified, then they
2065 @subsection Examples
2068 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2071 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2072 Since the sample format with name "s16p" corresponds to the number
2073 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2076 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2081 Generate an audio signal specified by an expression.
2083 This source accepts in input one or more expressions (one for each
2084 channel), which are evaluated and used to generate a corresponding
2087 This source accepts the following options:
2091 Set the '|'-separated expressions list for each separate channel. In case the
2092 @option{channel_layout} option is not specified, the selected channel layout
2093 depends on the number of provided expressions. Otherwise the last
2094 specified expression is applied to the remaining output channels.
2096 @item channel_layout, c
2097 Set the channel layout. The number of channels in the specified layout
2098 must be equal to the number of specified expressions.
2101 Set the minimum duration of the sourced audio. See the function
2102 @code{av_parse_time()} for the accepted format.
2103 Note that the resulting duration may be greater than the specified
2104 duration, as the generated audio is always cut at the end of a
2107 If not specified, or the expressed duration is negative, the audio is
2108 supposed to be generated forever.
2111 Set the number of samples per channel per each output frame,
2114 @item sample_rate, s
2115 Specify the sample rate, default to 44100.
2118 Each expression in @var{exprs} can contain the following constants:
2122 number of the evaluated sample, starting from 0
2125 time of the evaluated sample expressed in seconds, starting from 0
2132 @subsection Examples
2142 Generate a sin signal with frequency of 440 Hz, set sample rate to
2145 aevalsrc="sin(440*2*PI*t):s=8000"
2149 Generate a two channels signal, specify the channel layout (Front
2150 Center + Back Center) explicitly:
2152 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2156 Generate white noise:
2158 aevalsrc="-2+random(0)"
2162 Generate an amplitude modulated signal:
2164 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2168 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2170 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2177 The null audio source, return unprocessed audio frames. It is mainly useful
2178 as a template and to be employed in analysis / debugging tools, or as
2179 the source for filters which ignore the input data (for example the sox
2182 This source accepts the following options:
2186 @item channel_layout, cl
2188 Specifies the channel layout, and can be either an integer or a string
2189 representing a channel layout. The default value of @var{channel_layout}
2192 Check the channel_layout_map definition in
2193 @file{libavutil/channel_layout.c} for the mapping between strings and
2194 channel layout values.
2196 @item sample_rate, r
2197 Specifies the sample rate, and defaults to 44100.
2200 Set the number of samples per requested frames.
2204 @subsection Examples
2208 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2210 anullsrc=r=48000:cl=4
2214 Do the same operation with a more obvious syntax:
2216 anullsrc=r=48000:cl=mono
2220 All the parameters need to be explicitly defined.
2224 Synthesize a voice utterance using the libflite library.
2226 To enable compilation of this filter you need to configure FFmpeg with
2227 @code{--enable-libflite}.
2229 Note that the flite library is not thread-safe.
2231 The filter accepts the following options:
2236 If set to 1, list the names of the available voices and exit
2237 immediately. Default value is 0.
2240 Set the maximum number of samples per frame. Default value is 512.
2243 Set the filename containing the text to speak.
2246 Set the text to speak.
2249 Set the voice to use for the speech synthesis. Default value is
2250 @code{kal}. See also the @var{list_voices} option.
2253 @subsection Examples
2257 Read from file @file{speech.txt}, and synthetize the text using the
2258 standard flite voice:
2260 flite=textfile=speech.txt
2264 Read the specified text selecting the @code{slt} voice:
2266 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2270 Input text to ffmpeg:
2272 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2276 Make @file{ffplay} speak the specified text, using @code{flite} and
2277 the @code{lavfi} device:
2279 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2283 For more information about libflite, check:
2284 @url{http://www.speech.cs.cmu.edu/flite/}
2288 Generate an audio signal made of a sine wave with amplitude 1/8.
2290 The audio signal is bit-exact.
2292 The filter accepts the following options:
2297 Set the carrier frequency. Default is 440 Hz.
2299 @item beep_factor, b
2300 Enable a periodic beep every second with frequency @var{beep_factor} times
2301 the carrier frequency. Default is 0, meaning the beep is disabled.
2303 @item sample_rate, r
2304 Specify the sample rate, default is 44100.
2307 Specify the duration of the generated audio stream.
2309 @item samples_per_frame
2310 Set the number of samples per output frame, default is 1024.
2313 @subsection Examples
2318 Generate a simple 440 Hz sine wave:
2324 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2328 sine=frequency=220:beep_factor=4:duration=5
2333 @c man end AUDIO SOURCES
2335 @chapter Audio Sinks
2336 @c man begin AUDIO SINKS
2338 Below is a description of the currently available audio sinks.
2340 @section abuffersink
2342 Buffer audio frames, and make them available to the end of filter chain.
2344 This sink is mainly intended for programmatic use, in particular
2345 through the interface defined in @file{libavfilter/buffersink.h}
2346 or the options system.
2348 It accepts a pointer to an AVABufferSinkContext structure, which
2349 defines the incoming buffers' formats, to be passed as the opaque
2350 parameter to @code{avfilter_init_filter} for initialization.
2353 Null audio sink; do absolutely nothing with the input audio. It is
2354 mainly useful as a template and for use in analysis / debugging
2357 @c man end AUDIO SINKS
2359 @chapter Video Filters
2360 @c man begin VIDEO FILTERS
2362 When you configure your FFmpeg build, you can disable any of the
2363 existing filters using @code{--disable-filters}.
2364 The configure output will show the video filters included in your
2367 Below is a description of the currently available video filters.
2369 @section alphaextract
2371 Extract the alpha component from the input as a grayscale video. This
2372 is especially useful with the @var{alphamerge} filter.
2376 Add or replace the alpha component of the primary input with the
2377 grayscale value of a second input. This is intended for use with
2378 @var{alphaextract} to allow the transmission or storage of frame
2379 sequences that have alpha in a format that doesn't support an alpha
2382 For example, to reconstruct full frames from a normal YUV-encoded video
2383 and a separate video created with @var{alphaextract}, you might use:
2385 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2388 Since this filter is designed for reconstruction, it operates on frame
2389 sequences without considering timestamps, and terminates when either
2390 input reaches end of stream. This will cause problems if your encoding
2391 pipeline drops frames. If you're trying to apply an image as an
2392 overlay to a video stream, consider the @var{overlay} filter instead.
2396 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2397 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2398 Substation Alpha) subtitles files.
2402 Compute the bounding box for the non-black pixels in the input frame
2405 This filter computes the bounding box containing all the pixels with a
2406 luminance value greater than the minimum allowed value.
2407 The parameters describing the bounding box are printed on the filter
2410 The filter accepts the following option:
2414 Set the minimal luminance value. Default is @code{16}.
2417 @section blackdetect
2419 Detect video intervals that are (almost) completely black. Can be
2420 useful to detect chapter transitions, commercials, or invalid
2421 recordings. Output lines contains the time for the start, end and
2422 duration of the detected black interval expressed in seconds.
2424 In order to display the output lines, you need to set the loglevel at
2425 least to the AV_LOG_INFO value.
2427 The filter accepts the following options:
2430 @item black_min_duration, d
2431 Set the minimum detected black duration expressed in seconds. It must
2432 be a non-negative floating point number.
2434 Default value is 2.0.
2436 @item picture_black_ratio_th, pic_th
2437 Set the threshold for considering a picture "black".
2438 Express the minimum value for the ratio:
2440 @var{nb_black_pixels} / @var{nb_pixels}
2443 for which a picture is considered black.
2444 Default value is 0.98.
2446 @item pixel_black_th, pix_th
2447 Set the threshold for considering a pixel "black".
2449 The threshold expresses the maximum pixel luminance value for which a
2450 pixel is considered "black". The provided value is scaled according to
2451 the following equation:
2453 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2456 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2457 the input video format, the range is [0-255] for YUV full-range
2458 formats and [16-235] for YUV non full-range formats.
2460 Default value is 0.10.
2463 The following example sets the maximum pixel threshold to the minimum
2464 value, and detects only black intervals of 2 or more seconds:
2466 blackdetect=d=2:pix_th=0.00
2471 Detect frames that are (almost) completely black. Can be useful to
2472 detect chapter transitions or commercials. Output lines consist of
2473 the frame number of the detected frame, the percentage of blackness,
2474 the position in the file if known or -1 and the timestamp in seconds.
2476 In order to display the output lines, you need to set the loglevel at
2477 least to the AV_LOG_INFO value.
2479 It accepts the following parameters:
2484 The percentage of the pixels that have to be below the threshold; it defaults to
2487 @item threshold, thresh
2488 The threshold below which a pixel value is considered black; it defaults to
2495 Blend two video frames into each other.
2497 It takes two input streams and outputs one stream, the first input is the
2498 "top" layer and second input is "bottom" layer.
2499 Output terminates when shortest input terminates.
2501 A description of the accepted options follows.
2509 Set blend mode for specific pixel component or all pixel components in case
2510 of @var{all_mode}. Default value is @code{normal}.
2512 Available values for component modes are:
2545 Set blend opacity for specific pixel component or all pixel components in case
2546 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2553 Set blend expression for specific pixel component or all pixel components in case
2554 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2556 The expressions can use the following variables:
2560 The sequential number of the filtered frame, starting from @code{0}.
2564 the coordinates of the current sample
2568 the width and height of currently filtered plane
2572 Width and height scale depending on the currently filtered plane. It is the
2573 ratio between the corresponding luma plane number of pixels and the current
2574 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2575 @code{0.5,0.5} for chroma planes.
2578 Time of the current frame, expressed in seconds.
2581 Value of pixel component at current location for first video frame (top layer).
2584 Value of pixel component at current location for second video frame (bottom layer).
2588 Force termination when the shortest input terminates. Default is @code{0}.
2590 Continue applying the last bottom frame after the end of the stream. A value of
2591 @code{0} disable the filter after the last frame of the bottom layer is reached.
2592 Default is @code{1}.
2595 @subsection Examples
2599 Apply transition from bottom layer to top layer in first 10 seconds:
2601 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2605 Apply 1x1 checkerboard effect:
2607 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2611 Apply uncover left effect:
2613 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2617 Apply uncover down effect:
2619 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2623 Apply uncover up-left effect:
2625 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2631 Apply a boxblur algorithm to the input video.
2633 It accepts the following parameters:
2637 @item luma_radius, lr
2638 @item luma_power, lp
2639 @item chroma_radius, cr
2640 @item chroma_power, cp
2641 @item alpha_radius, ar
2642 @item alpha_power, ap
2646 A description of the accepted options follows.
2649 @item luma_radius, lr
2650 @item chroma_radius, cr
2651 @item alpha_radius, ar
2652 Set an expression for the box radius in pixels used for blurring the
2653 corresponding input plane.
2655 The radius value must be a non-negative number, and must not be
2656 greater than the value of the expression @code{min(w,h)/2} for the
2657 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2660 Default value for @option{luma_radius} is "2". If not specified,
2661 @option{chroma_radius} and @option{alpha_radius} default to the
2662 corresponding value set for @option{luma_radius}.
2664 The expressions can contain the following constants:
2668 The input width and height in pixels.
2672 The input chroma image width and height in pixels.
2676 The horizontal and vertical chroma subsample values. For example, for the
2677 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2680 @item luma_power, lp
2681 @item chroma_power, cp
2682 @item alpha_power, ap
2683 Specify how many times the boxblur filter is applied to the
2684 corresponding plane.
2686 Default value for @option{luma_power} is 2. If not specified,
2687 @option{chroma_power} and @option{alpha_power} default to the
2688 corresponding value set for @option{luma_power}.
2690 A value of 0 will disable the effect.
2693 @subsection Examples
2697 Apply a boxblur filter with the luma, chroma, and alpha radii
2700 boxblur=luma_radius=2:luma_power=1
2705 Set the luma radius to 2, and alpha and chroma radius to 0:
2707 boxblur=2:1:cr=0:ar=0
2711 Set the luma and chroma radii to a fraction of the video dimension:
2713 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2717 @section colorbalance
2718 Modify intensity of primary colors (red, green and blue) of input frames.
2720 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2721 regions for the red-cyan, green-magenta or blue-yellow balance.
2723 A positive adjustment value shifts the balance towards the primary color, a negative
2724 value towards the complementary color.
2726 The filter accepts the following options:
2732 Adjust red, green and blue shadows (darkest pixels).
2737 Adjust red, green and blue midtones (medium pixels).
2742 Adjust red, green and blue highlights (brightest pixels).
2744 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2747 @subsection Examples
2751 Add red color cast to shadows:
2757 @section colorchannelmixer
2759 Adjust video input frames by re-mixing color channels.
2761 This filter modifies a color channel by adding the values associated to
2762 the other channels of the same pixels. For example if the value to
2763 modify is red, the output value will be:
2765 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2768 The filter accepts the following options:
2775 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2776 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2782 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2783 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2789 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2790 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2796 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2797 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2799 Allowed ranges for options are @code{[-2.0, 2.0]}.
2802 @subsection Examples
2806 Convert source to grayscale:
2808 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2811 Simulate sepia tones:
2813 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2817 @section colormatrix
2819 Convert color matrix.
2821 The filter accepts the following options:
2826 Specify the source and destination color matrix. Both values must be
2829 The accepted values are:
2845 For example to convert from BT.601 to SMPTE-240M, use the command:
2847 colormatrix=bt601:smpte240m
2852 Copy the input source unchanged to the output. This is mainly useful for
2857 Crop the input video to given dimensions.
2859 It accepts the following parameters:
2863 The width of the output video. It defaults to @code{iw}.
2864 This expression is evaluated only once during the filter
2868 The height of the output video. It defaults to @code{ih}.
2869 This expression is evaluated only once during the filter
2873 The horizontal position, in the input video, of the left edge of the output
2874 video. It defaults to @code{(in_w-out_w)/2}.
2875 This expression is evaluated per-frame.
2878 The vertical position, in the input video, of the top edge of the output video.
2879 It defaults to @code{(in_h-out_h)/2}.
2880 This expression is evaluated per-frame.
2883 If set to 1 will force the output display aspect ratio
2884 to be the same of the input, by changing the output sample aspect
2885 ratio. It defaults to 0.
2888 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2889 expressions containing the following constants:
2894 The computed values for @var{x} and @var{y}. They are evaluated for
2899 The input width and height.
2903 These are the same as @var{in_w} and @var{in_h}.
2907 The output (cropped) width and height.
2911 These are the same as @var{out_w} and @var{out_h}.
2914 same as @var{iw} / @var{ih}
2917 input sample aspect ratio
2920 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2924 horizontal and vertical chroma subsample values. For example for the
2925 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2928 The number of the input frame, starting from 0.
2931 the position in the file of the input frame, NAN if unknown
2934 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
2938 The expression for @var{out_w} may depend on the value of @var{out_h},
2939 and the expression for @var{out_h} may depend on @var{out_w}, but they
2940 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2941 evaluated after @var{out_w} and @var{out_h}.
2943 The @var{x} and @var{y} parameters specify the expressions for the
2944 position of the top-left corner of the output (non-cropped) area. They
2945 are evaluated for each frame. If the evaluated value is not valid, it
2946 is approximated to the nearest valid value.
2948 The expression for @var{x} may depend on @var{y}, and the expression
2949 for @var{y} may depend on @var{x}.
2951 @subsection Examples
2955 Crop area with size 100x100 at position (12,34).
2960 Using named options, the example above becomes:
2962 crop=w=100:h=100:x=12:y=34
2966 Crop the central input area with size 100x100:
2972 Crop the central input area with size 2/3 of the input video:
2974 crop=2/3*in_w:2/3*in_h
2978 Crop the input video central square:
2985 Delimit the rectangle with the top-left corner placed at position
2986 100:100 and the right-bottom corner corresponding to the right-bottom
2987 corner of the input image.
2989 crop=in_w-100:in_h-100:100:100
2993 Crop 10 pixels from the left and right borders, and 20 pixels from
2994 the top and bottom borders
2996 crop=in_w-2*10:in_h-2*20
3000 Keep only the bottom right quarter of the input image:
3002 crop=in_w/2:in_h/2:in_w/2:in_h/2
3006 Crop height for getting Greek harmony:
3008 crop=in_w:1/PHI*in_w
3012 Appply trembling effect:
3014 crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)
3018 Apply erratic camera effect depending on timestamp:
3020 crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
3024 Set x depending on the value of y:
3026 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3032 Auto-detect the crop size.
3034 It calculates the necessary cropping parameters and prints the
3035 recommended parameters via the logging system. The detected dimensions
3036 correspond to the non-black area of the input video.
3038 It accepts the following parameters:
3043 Set higher black value threshold, which can be optionally specified
3044 from nothing (0) to everything (255). An intensity value greater
3045 to the set value is considered non-black. It defaults to 24.
3048 The value which the width/height should be divisible by. It defaults to
3049 16. The offset is automatically adjusted to center the video. Use 2 to
3050 get only even dimensions (needed for 4:2:2 video). 16 is best when
3051 encoding to most video codecs.
3053 @item reset_count, reset
3054 Set the counter that determines after how many frames cropdetect will
3055 reset the previously detected largest video area and start over to
3056 detect the current optimal crop area. Default value is 0.
3058 This can be useful when channel logos distort the video area. 0
3059 indicates 'never reset', and returns the largest area encountered during
3066 Apply color adjustments using curves.
3068 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3069 component (red, green and blue) has its values defined by @var{N} key points
3070 tied from each other using a smooth curve. The x-axis represents the pixel
3071 values from the input frame, and the y-axis the new pixel values to be set for
3074 By default, a component curve is defined by the two points @var{(0;0)} and
3075 @var{(1;1)}. This creates a straight line where each original pixel value is
3076 "adjusted" to its own value, which means no change to the image.
3078 The filter allows you to redefine these two points and add some more. A new
3079 curve (using a natural cubic spline interpolation) will be define to pass
3080 smoothly through all these new coordinates. The new defined points needs to be
3081 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3082 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3083 the vector spaces, the values will be clipped accordingly.
3085 If there is no key point defined in @code{x=0}, the filter will automatically
3086 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3087 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3089 The filter accepts the following options:
3093 Select one of the available color presets. This option can be used in addition
3094 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3095 options takes priority on the preset values.
3096 Available presets are:
3099 @item color_negative
3102 @item increase_contrast
3104 @item linear_contrast
3105 @item medium_contrast
3107 @item strong_contrast
3110 Default is @code{none}.
3112 Set the master key points. These points will define a second pass mapping. It
3113 is sometimes called a "luminance" or "value" mapping. It can be used with
3114 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3115 post-processing LUT.
3117 Set the key points for the red component.
3119 Set the key points for the green component.
3121 Set the key points for the blue component.
3123 Set the key points for all components (not including master).
3124 Can be used in addition to the other key points component
3125 options. In this case, the unset component(s) will fallback on this
3126 @option{all} setting.
3128 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3131 To avoid some filtergraph syntax conflicts, each key points list need to be
3132 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3134 @subsection Examples
3138 Increase slightly the middle level of blue:
3140 curves=blue='0.5/0.58'
3146 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3148 Here we obtain the following coordinates for each components:
3151 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3153 @code{(0;0) (0.50;0.48) (1;1)}
3155 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3159 The previous example can also be achieved with the associated built-in preset:
3161 curves=preset=vintage
3171 Use a Photoshop preset and redefine the points of the green component:
3173 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3179 Denoise frames using 2D DCT (frequency domain filtering).
3181 This filter is not designed for real time and can be extremely slow.
3183 The filter accepts the following options:
3187 Set the noise sigma constant.
3189 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3190 coefficient (absolute value) below this threshold with be dropped.
3192 If you need a more advanced filtering, see @option{expr}.
3194 Default is @code{0}.
3197 Set number overlapping pixels for each block. Each block is of size
3198 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
3199 at the cost of a less effective filter and the risk of various artefacts.
3201 If the overlapping value doesn't allow to process the whole input width or
3202 height, a warning will be displayed and according borders won't be denoised.
3204 Default value is @code{15}.
3207 Set the coefficient factor expression.
3209 For each coefficient of a DCT block, this expression will be evaluated as a
3210 multiplier value for the coefficient.
3212 If this is option is set, the @option{sigma} option will be ignored.
3214 The absolute value of the coefficient can be accessed through the @var{c}
3218 @subsection Examples
3220 Apply a denoise with a @option{sigma} of @code{4.5}:
3225 The same operation can be achieved using the expression system:
3227 dctdnoiz=e='gte(c, 4.5*3)'
3233 Drop duplicated frames at regular intervals.
3235 The filter accepts the following options:
3239 Set the number of frames from which one will be dropped. Setting this to
3240 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3241 Default is @code{5}.
3244 Set the threshold for duplicate detection. If the difference metric for a frame
3245 is less than or equal to this value, then it is declared as duplicate. Default
3249 Set scene change threshold. Default is @code{15}.
3253 Set the size of the x and y-axis blocks used during metric calculations.
3254 Larger blocks give better noise suppression, but also give worse detection of
3255 small movements. Must be a power of two. Default is @code{32}.
3258 Mark main input as a pre-processed input and activate clean source input
3259 stream. This allows the input to be pre-processed with various filters to help
3260 the metrics calculation while keeping the frame selection lossless. When set to
3261 @code{1}, the first stream is for the pre-processed input, and the second
3262 stream is the clean source from where the kept frames are chosen. Default is
3266 Set whether or not chroma is considered in the metric calculations. Default is
3272 Remove judder produced by partially interlaced telecined content.
3274 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3275 source was partially telecined content then the output of @code{pullup,dejudder}
3276 will have a variable frame rate. May change the recorded frame rate of the
3277 container. Aside from that change, this filter will not affect constant frame
3280 The option available in this filter is:
3284 Specify the length of the window over which the judder repeats.
3286 Accepts any interger greater than 1. Useful values are:
3290 If the original was telecined from 24 to 30 fps (Film to NTSC).
3293 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3296 If a mixture of the two.
3299 The default is @samp{4}.
3304 Suppress a TV station logo by a simple interpolation of the surrounding
3305 pixels. Just set a rectangle covering the logo and watch it disappear
3306 (and sometimes something even uglier appear - your mileage may vary).
3308 It accepts the following parameters:
3313 Specify the top left corner coordinates of the logo. They must be
3318 Specify the width and height of the logo to clear. They must be
3322 Specify the thickness of the fuzzy edge of the rectangle (added to
3323 @var{w} and @var{h}). The default value is 4.
3326 When set to 1, a green rectangle is drawn on the screen to simplify
3327 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3328 The default value is 0.
3330 The rectangle is drawn on the outermost pixels which will be (partly)
3331 replaced with interpolated values. The values of the next pixels
3332 immediately outside this rectangle in each direction will be used to
3333 compute the interpolated pixel values inside the rectangle.
3337 @subsection Examples
3341 Set a rectangle covering the area with top left corner coordinates 0,0
3342 and size 100x77, and a band of size 10:
3344 delogo=x=0:y=0:w=100:h=77:band=10
3351 Attempt to fix small changes in horizontal and/or vertical shift. This
3352 filter helps remove camera shake from hand-holding a camera, bumping a
3353 tripod, moving on a vehicle, etc.
3355 The filter accepts the following options:
3363 Specify a rectangular area where to limit the search for motion
3365 If desired the search for motion vectors can be limited to a
3366 rectangular area of the frame defined by its top left corner, width
3367 and height. These parameters have the same meaning as the drawbox
3368 filter which can be used to visualise the position of the bounding
3371 This is useful when simultaneous movement of subjects within the frame
3372 might be confused for camera motion by the motion vector search.
3374 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3375 then the full frame is used. This allows later options to be set
3376 without specifying the bounding box for the motion vector search.
3378 Default - search the whole frame.
3382 Specify the maximum extent of movement in x and y directions in the
3383 range 0-64 pixels. Default 16.
3386 Specify how to generate pixels to fill blanks at the edge of the
3387 frame. Available values are:
3390 Fill zeroes at blank locations
3392 Original image at blank locations
3394 Extruded edge value at blank locations
3396 Mirrored edge at blank locations
3398 Default value is @samp{mirror}.
3401 Specify the blocksize to use for motion search. Range 4-128 pixels,
3405 Specify the contrast threshold for blocks. Only blocks with more than
3406 the specified contrast (difference between darkest and lightest
3407 pixels) will be considered. Range 1-255, default 125.
3410 Specify the search strategy. Available values are:
3413 Set exhaustive search
3415 Set less exhaustive search.
3417 Default value is @samp{exhaustive}.
3420 If set then a detailed log of the motion search is written to the
3424 If set to 1, specify using OpenCL capabilities, only available if
3425 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3431 Draw a colored box on the input image.
3433 It accepts the following parameters:
3438 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3442 The expressions which specify the width and height of the box; if 0 they are interpreted as
3443 the input width and height. It defaults to 0.
3446 Specify the color of the box to write. For the general syntax of this option,
3447 check the "Color" section in the ffmpeg-utils manual. If the special
3448 value @code{invert} is used, the box edge color is the same as the
3449 video with inverted luma.
3452 The expression which sets the thickness of the box edge. Default value is @code{3}.
3454 See below for the list of accepted constants.
3457 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3458 following constants:
3462 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3466 horizontal and vertical chroma subsample values. For example for the
3467 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3471 The input width and height.
3474 The input sample aspect ratio.
3478 The x and y offset coordinates where the box is drawn.
3482 The width and height of the drawn box.
3485 The thickness of the drawn box.
3487 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3488 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3492 @subsection Examples
3496 Draw a black box around the edge of the input image:
3502 Draw a box with color red and an opacity of 50%:
3504 drawbox=10:20:200:60:red@@0.5
3507 The previous example can be specified as:
3509 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3513 Fill the box with pink color:
3515 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3519 Draw a 2-pixel red 2.40:1 mask:
3521 drawbox=x=-t:y=0.5*(ih-iw/2.4)-t:w=iw+t*2:h=iw/2.4+t*2:t=2:c=red
3527 Draw a grid on the input image.
3529 It accepts the following parameters:
3534 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3538 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3539 input width and height, respectively, minus @code{thickness}, so image gets
3540 framed. Default to 0.
3543 Specify the color of the grid. For the general syntax of this option,
3544 check the "Color" section in the ffmpeg-utils manual. If the special
3545 value @code{invert} is used, the grid color is the same as the
3546 video with inverted luma.
3549 The expression which sets the thickness of the grid line. Default value is @code{1}.
3551 See below for the list of accepted constants.
3554 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3555 following constants:
3559 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3563 horizontal and vertical chroma subsample values. For example for the
3564 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3568 The input grid cell width and height.
3571 The input sample aspect ratio.
3575 The x and y coordinates of some point of grid intersection (meant to configure offset).
3579 The width and height of the drawn cell.
3582 The thickness of the drawn cell.
3584 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3585 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3589 @subsection Examples
3593 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3595 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3599 Draw a white 3x3 grid with an opacity of 50%:
3601 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3608 Draw a text string or text from a specified file on top of a video, using the
3609 libfreetype library.
3611 To enable compilation of this filter, you need to configure FFmpeg with
3612 @code{--enable-libfreetype}.
3613 To enable default font fallback and the @var{font} option you need to
3614 configure FFmpeg with @code{--enable-libfontconfig}.
3618 It accepts the following parameters:
3623 Used to draw a box around text using the background color.
3624 The value must be either 1 (enable) or 0 (disable).
3625 The default value of @var{box} is 0.
3628 The color to be used for drawing box around text. For the syntax of this
3629 option, check the "Color" section in the ffmpeg-utils manual.
3631 The default value of @var{boxcolor} is "white".
3634 Set the width of the border to be drawn around the text using @var{bordercolor}.
3635 The default value of @var{borderw} is 0.
3638 Set the color to be used for drawing border around text. For the syntax of this
3639 option, check the "Color" section in the ffmpeg-utils manual.
3641 The default value of @var{bordercolor} is "black".
3644 Select how the @var{text} is expanded. Can be either @code{none},
3645 @code{strftime} (deprecated) or
3646 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3650 If true, check and fix text coords to avoid clipping.
3653 The color to be used for drawing fonts. For the syntax of this option, check
3654 the "Color" section in the ffmpeg-utils manual.
3656 The default value of @var{fontcolor} is "black".
3659 The font family to be used for drawing text. By default Sans.
3662 The font file to be used for drawing text. The path must be included.
3663 This parameter is mandatory if the fontconfig support is disabled.
3666 The font size to be used for drawing text.
3667 The default value of @var{fontsize} is 16.
3670 The flags to be used for loading the fonts.
3672 The flags map the corresponding flags supported by libfreetype, and are
3673 a combination of the following values:
3680 @item vertical_layout
3681 @item force_autohint
3684 @item ignore_global_advance_width
3686 @item ignore_transform
3692 Default value is "default".
3694 For more information consult the documentation for the FT_LOAD_*
3698 The color to be used for drawing a shadow behind the drawn text. For the
3699 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3701 The default value of @var{shadowcolor} is "black".
3705 The x and y offsets for the text shadow position with respect to the
3706 position of the text. They can be either positive or negative
3707 values. The default value for both is "0".
3710 The starting frame number for the n/frame_num variable. The default value
3714 The size in number of spaces to use for rendering the tab.
3718 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3719 format. It can be used with or without text parameter. @var{timecode_rate}
3720 option must be specified.
3722 @item timecode_rate, rate, r
3723 Set the timecode frame rate (timecode only).
3726 The text string to be drawn. The text must be a sequence of UTF-8
3728 This parameter is mandatory if no file is specified with the parameter
3732 A text file containing text to be drawn. The text must be a sequence
3733 of UTF-8 encoded characters.
3735 This parameter is mandatory if no text string is specified with the
3736 parameter @var{text}.
3738 If both @var{text} and @var{textfile} are specified, an error is thrown.
3741 If set to 1, the @var{textfile} will be reloaded before each frame.
3742 Be sure to update it atomically, or it may be read partially, or even fail.
3746 The expressions which specify the offsets where text will be drawn
3747 within the video frame. They are relative to the top/left border of the
3750 The default value of @var{x} and @var{y} is "0".
3752 See below for the list of accepted constants and functions.
3755 The parameters for @var{x} and @var{y} are expressions containing the
3756 following constants and functions:
3760 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3764 horizontal and vertical chroma subsample values. For example for the
3765 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3768 the height of each text line
3776 @item max_glyph_a, ascent
3777 the maximum distance from the baseline to the highest/upper grid
3778 coordinate used to place a glyph outline point, for all the rendered
3780 It is a positive value, due to the grid's orientation with the Y axis
3783 @item max_glyph_d, descent
3784 the maximum distance from the baseline to the lowest grid coordinate
3785 used to place a glyph outline point, for all the rendered glyphs.
3786 This is a negative value, due to the grid's orientation, with the Y axis
3790 maximum glyph height, that is the maximum height for all the glyphs
3791 contained in the rendered text, it is equivalent to @var{ascent} -
3795 maximum glyph width, that is the maximum width for all the glyphs
3796 contained in the rendered text
3799 the number of input frame, starting from 0
3801 @item rand(min, max)
3802 return a random number included between @var{min} and @var{max}
3805 The input sample aspect ratio.
3808 timestamp expressed in seconds, NAN if the input timestamp is unknown
3811 the height of the rendered text
3814 the width of the rendered text
3818 the x and y offset coordinates where the text is drawn.
3820 These parameters allow the @var{x} and @var{y} expressions to refer
3821 each other, so you can for example specify @code{y=x/dar}.
3824 @anchor{drawtext_expansion}
3825 @subsection Text expansion
3827 If @option{expansion} is set to @code{strftime},
3828 the filter recognizes strftime() sequences in the provided text and
3829 expands them accordingly. Check the documentation of strftime(). This
3830 feature is deprecated.
3832 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3834 If @option{expansion} is set to @code{normal} (which is the default),
3835 the following expansion mechanism is used.
3837 The backslash character '\', followed by any character, always expands to
3838 the second character.
3840 Sequence of the form @code{%@{...@}} are expanded. The text between the
3841 braces is a function name, possibly followed by arguments separated by ':'.
3842 If the arguments contain special characters or delimiters (':' or '@}'),
3843 they should be escaped.
3845 Note that they probably must also be escaped as the value for the
3846 @option{text} option in the filter argument string and as the filter
3847 argument in the filtergraph description, and possibly also for the shell,
3848 that makes up to four levels of escaping; using a text file avoids these
3851 The following functions are available:
3856 The expression evaluation result.
3858 It must take one argument specifying the expression to be evaluated,
3859 which accepts the same constants and functions as the @var{x} and
3860 @var{y} values. Note that not all constants should be used, for
3861 example the text size is not known when evaluating the expression, so
3862 the constants @var{text_w} and @var{text_h} will have an undefined
3866 The time at which the filter is running, expressed in UTC.
3867 It can accept an argument: a strftime() format string.
3870 The time at which the filter is running, expressed in the local time zone.
3871 It can accept an argument: a strftime() format string.
3874 Frame metadata. It must take one argument specifying metadata key.
3877 The frame number, starting from 0.
3880 A 1 character description of the current picture type.
3883 The timestamp of the current frame.
3884 It can take up to two arguments.
3886 The first argument is the format of the timestamp; it defaults to @code{flt}
3887 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
3888 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
3890 The second argument is an offset added to the timestamp.
3894 @subsection Examples
3898 Draw "Test Text" with font FreeSerif, using the default values for the
3899 optional parameters.
3902 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3906 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3907 and y=50 (counting from the top-left corner of the screen), text is
3908 yellow with a red box around it. Both the text and the box have an
3912 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3913 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3916 Note that the double quotes are not necessary if spaces are not used
3917 within the parameter list.
3920 Show the text at the center of the video frame:
3922 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3926 Show a text line sliding from right to left in the last row of the video
3927 frame. The file @file{LONG_LINE} is assumed to contain a single line
3930 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3934 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3936 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3940 Draw a single green letter "g", at the center of the input video.
3941 The glyph baseline is placed at half screen height.
3943 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3947 Show text for 1 second every 3 seconds:
3949 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
3953 Use fontconfig to set the font. Note that the colons need to be escaped.
3955 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3959 Print the date of a real-time encoding (see strftime(3)):
3961 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3966 For more information about libfreetype, check:
3967 @url{http://www.freetype.org/}.
3969 For more information about fontconfig, check:
3970 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3974 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3976 The filter accepts the following options:
3981 Set low and high threshold values used by the Canny thresholding
3984 The high threshold selects the "strong" edge pixels, which are then
3985 connected through 8-connectivity with the "weak" edge pixels selected
3986 by the low threshold.
3988 @var{low} and @var{high} threshold values must be chosen in the range
3989 [0,1], and @var{low} should be lesser or equal to @var{high}.
3991 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3995 Define the drawing mode.
3999 Draw white/gray wires on black background.
4002 Mix the colors to create a paint/cartoon effect.
4005 Default value is @var{wires}.
4008 @subsection Examples
4012 Standard edge detection with custom values for the hysteresis thresholding:
4014 edgedetect=low=0.1:high=0.4
4018 Painting effect without thresholding:
4020 edgedetect=mode=colormix:high=0
4024 @section extractplanes
4026 Extract color channel components from input video stream into
4027 separate grayscale video streams.
4029 The filter accepts the following option:
4033 Set plane(s) to extract.
4035 Available values for planes are:
4046 Choosing planes not available in the input will result in an error.
4047 That means you cannot select @code{r}, @code{g}, @code{b} planes
4048 with @code{y}, @code{u}, @code{v} planes at same time.
4051 @subsection Examples
4055 Extract luma, u and v color channel component from input video frame
4056 into 3 grayscale outputs:
4058 ffmpeg -i video.avi -filter_complex 'extractplanes=y+u+v[y][u][v]' -map '[y]' y.avi -map '[u]' u.avi -map '[v]' v.avi
4064 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4066 For each input image, the filter will compute the optimal mapping from
4067 the input to the output given the codebook length, that is the number
4068 of distinct output colors.
4070 This filter accepts the following options.
4073 @item codebook_length, l
4074 Set codebook length. The value must be a positive integer, and
4075 represents the number of distinct output colors. Default value is 256.
4078 Set the maximum number of iterations to apply for computing the optimal
4079 mapping. The higher the value the better the result and the higher the
4080 computation time. Default value is 1.
4083 Set a random seed, must be an integer included between 0 and
4084 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4085 will try to use a good random seed on a best effort basis.
4090 Apply a fade-in/out effect to the input video.
4092 It accepts the following parameters:
4096 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4098 Default is @code{in}.
4100 @item start_frame, s
4101 Specify the number of the frame to start applying the fade
4102 effect at. Default is 0.
4105 The number of frames that the fade effect lasts. At the end of the
4106 fade-in effect, the output video will have the same intensity as the input video.
4107 At the end of the fade-out transition, the output video will be filled with the
4108 selected @option{color}.
4112 If set to 1, fade only alpha channel, if one exists on the input.
4115 @item start_time, st
4116 Specify the timestamp (in seconds) of the frame to start to apply the fade
4117 effect. If both start_frame and start_time are specified, the fade will start at
4118 whichever comes last. Default is 0.
4121 The number of seconds for which the fade effect has to last. At the end of the
4122 fade-in effect the output video will have the same intensity as the input video,
4123 at the end of the fade-out transition the output video will be filled with the
4124 selected @option{color}.
4125 If both duration and nb_frames are specified, duration is used. Default is 0.
4128 Specify the color of the fade. Default is "black".
4131 @subsection Examples
4135 Fade in the first 30 frames of video:
4140 The command above is equivalent to:
4146 Fade out the last 45 frames of a 200-frame video:
4149 fade=type=out:start_frame=155:nb_frames=45
4153 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4155 fade=in:0:25, fade=out:975:25
4159 Make the first 5 frames yellow, then fade in from frame 5-24:
4161 fade=in:5:20:color=yellow
4165 Fade in alpha over first 25 frames of video:
4167 fade=in:0:25:alpha=1
4171 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4173 fade=t=in:st=5.5:d=0.5
4180 Extract a single field from an interlaced image using stride
4181 arithmetic to avoid wasting CPU time. The output frames are marked as
4184 The filter accepts the following options:
4188 Specify whether to extract the top (if the value is @code{0} or
4189 @code{top}) or the bottom field (if the value is @code{1} or
4195 Field matching filter for inverse telecine. It is meant to reconstruct the
4196 progressive frames from a telecined stream. The filter does not drop duplicated
4197 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4198 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4200 The separation of the field matching and the decimation is notably motivated by
4201 the possibility of inserting a de-interlacing filter fallback between the two.
4202 If the source has mixed telecined and real interlaced content,
4203 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4204 But these remaining combed frames will be marked as interlaced, and thus can be
4205 de-interlaced by a later filter such as @ref{yadif} before decimation.
4207 In addition to the various configuration options, @code{fieldmatch} can take an
4208 optional second stream, activated through the @option{ppsrc} option. If
4209 enabled, the frames reconstruction will be based on the fields and frames from
4210 this second stream. This allows the first input to be pre-processed in order to
4211 help the various algorithms of the filter, while keeping the output lossless
4212 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4213 or brightness/contrast adjustments can help.
4215 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4216 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4217 which @code{fieldmatch} is based on. While the semantic and usage are very
4218 close, some behaviour and options names can differ.
4220 The filter accepts the following options:
4224 Specify the assumed field order of the input stream. Available values are:
4228 Auto detect parity (use FFmpeg's internal parity value).
4230 Assume bottom field first.
4232 Assume top field first.
4235 Note that it is sometimes recommended not to trust the parity announced by the
4238 Default value is @var{auto}.
4241 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4242 sense that it won't risk creating jerkiness due to duplicate frames when
4243 possible, but if there are bad edits or blended fields it will end up
4244 outputting combed frames when a good match might actually exist. On the other
4245 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4246 but will almost always find a good frame if there is one. The other values are
4247 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4248 jerkiness and creating duplicate frames versus finding good matches in sections
4249 with bad edits, orphaned fields, blended fields, etc.
4251 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4253 Available values are:
4257 2-way matching (p/c)
4259 2-way matching, and trying 3rd match if still combed (p/c + n)
4261 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4263 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4264 still combed (p/c + n + u/b)
4266 3-way matching (p/c/n)
4268 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4269 detected as combed (p/c/n + u/b)
4272 The parenthesis at the end indicate the matches that would be used for that
4273 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4276 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4279 Default value is @var{pc_n}.
4282 Mark the main input stream as a pre-processed input, and enable the secondary
4283 input stream as the clean source to pick the fields from. See the filter
4284 introduction for more details. It is similar to the @option{clip2} feature from
4287 Default value is @code{0} (disabled).
4290 Set the field to match from. It is recommended to set this to the same value as
4291 @option{order} unless you experience matching failures with that setting. In
4292 certain circumstances changing the field that is used to match from can have a
4293 large impact on matching performance. Available values are:
4297 Automatic (same value as @option{order}).
4299 Match from the bottom field.
4301 Match from the top field.
4304 Default value is @var{auto}.
4307 Set whether or not chroma is included during the match comparisons. In most
4308 cases it is recommended to leave this enabled. You should set this to @code{0}
4309 only if your clip has bad chroma problems such as heavy rainbowing or other
4310 artifacts. Setting this to @code{0} could also be used to speed things up at
4311 the cost of some accuracy.
4313 Default value is @code{1}.
4317 These define an exclusion band which excludes the lines between @option{y0} and
4318 @option{y1} from being included in the field matching decision. An exclusion
4319 band can be used to ignore subtitles, a logo, or other things that may
4320 interfere with the matching. @option{y0} sets the starting scan line and
4321 @option{y1} sets the ending line; all lines in between @option{y0} and
4322 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4323 @option{y0} and @option{y1} to the same value will disable the feature.
4324 @option{y0} and @option{y1} defaults to @code{0}.
4327 Set the scene change detection threshold as a percentage of maximum change on
4328 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4329 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4330 @option{scthresh} is @code{[0.0, 100.0]}.
4332 Default value is @code{12.0}.
4335 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4336 account the combed scores of matches when deciding what match to use as the
4337 final match. Available values are:
4341 No final matching based on combed scores.
4343 Combed scores are only used when a scene change is detected.
4345 Use combed scores all the time.
4348 Default is @var{sc}.
4351 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4352 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4353 Available values are:
4357 No forced calculation.
4359 Force p/c/n calculations.
4361 Force p/c/n/u/b calculations.
4364 Default value is @var{none}.
4367 This is the area combing threshold used for combed frame detection. This
4368 essentially controls how "strong" or "visible" combing must be to be detected.
4369 Larger values mean combing must be more visible and smaller values mean combing
4370 can be less visible or strong and still be detected. Valid settings are from
4371 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4372 be detected as combed). This is basically a pixel difference value. A good
4373 range is @code{[8, 12]}.
4375 Default value is @code{9}.
4378 Sets whether or not chroma is considered in the combed frame decision. Only
4379 disable this if your source has chroma problems (rainbowing, etc.) that are
4380 causing problems for the combed frame detection with chroma enabled. Actually,
4381 using @option{chroma}=@var{0} is usually more reliable, except for the case
4382 where there is chroma only combing in the source.
4384 Default value is @code{0}.
4388 Respectively set the x-axis and y-axis size of the window used during combed
4389 frame detection. This has to do with the size of the area in which
4390 @option{combpel} pixels are required to be detected as combed for a frame to be
4391 declared combed. See the @option{combpel} parameter description for more info.
4392 Possible values are any number that is a power of 2 starting at 4 and going up
4395 Default value is @code{16}.
4398 The number of combed pixels inside any of the @option{blocky} by
4399 @option{blockx} size blocks on the frame for the frame to be detected as
4400 combed. While @option{cthresh} controls how "visible" the combing must be, this
4401 setting controls "how much" combing there must be in any localized area (a
4402 window defined by the @option{blockx} and @option{blocky} settings) on the
4403 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4404 which point no frames will ever be detected as combed). This setting is known
4405 as @option{MI} in TFM/VFM vocabulary.
4407 Default value is @code{80}.
4410 @anchor{p/c/n/u/b meaning}
4411 @subsection p/c/n/u/b meaning
4413 @subsubsection p/c/n
4415 We assume the following telecined stream:
4418 Top fields: 1 2 2 3 4
4419 Bottom fields: 1 2 3 4 4
4422 The numbers correspond to the progressive frame the fields relate to. Here, the
4423 first two frames are progressive, the 3rd and 4th are combed, and so on.
4425 When @code{fieldmatch} is configured to run a matching from bottom
4426 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4431 B 1 2 3 4 4 <-- matching reference
4440 As a result of the field matching, we can see that some frames get duplicated.
4441 To perform a complete inverse telecine, you need to rely on a decimation filter
4442 after this operation. See for instance the @ref{decimate} filter.
4444 The same operation now matching from top fields (@option{field}=@var{top})
4449 T 1 2 2 3 4 <-- matching reference
4459 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4460 basically, they refer to the frame and field of the opposite parity:
4463 @item @var{p} matches the field of the opposite parity in the previous frame
4464 @item @var{c} matches the field of the opposite parity in the current frame
4465 @item @var{n} matches the field of the opposite parity in the next frame
4470 The @var{u} and @var{b} matching are a bit special in the sense that they match
4471 from the opposite parity flag. In the following examples, we assume that we are
4472 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4473 'x' is placed above and below each matched fields.
4475 With bottom matching (@option{field}=@var{bottom}):
4480 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4481 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4489 With top matching (@option{field}=@var{top}):
4494 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4495 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4503 @subsection Examples
4505 Simple IVTC of a top field first telecined stream:
4507 fieldmatch=order=tff:combmatch=none, decimate
4510 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4512 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4517 Transform the field order of the input video.
4519 It accepts the following parameters:
4524 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4525 for bottom field first.
4528 The default value is @samp{tff}.
4530 The transformation is done by shifting the picture content up or down
4531 by one line, and filling the remaining line with appropriate picture content.
4532 This method is consistent with most broadcast field order converters.
4534 If the input video is not flagged as being interlaced, or it is already
4535 flagged as being of the required output field order, then this filter does
4536 not alter the incoming video.
4538 It is very useful when converting to or from PAL DV material,
4539 which is bottom field first.
4543 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4548 Buffer input images and send them when they are requested.
4550 It is mainly useful when auto-inserted by the libavfilter
4553 It does not take parameters.
4558 Convert the input video to one of the specified pixel formats.
4559 Libavfilter will try to pick one that is suitable as input to
4562 It accepts the following parameters:
4566 A '|'-separated list of pixel format names, such as
4567 "pix_fmts=yuv420p|monow|rgb24".
4571 @subsection Examples
4575 Convert the input video to the @var{yuv420p} format
4577 format=pix_fmts=yuv420p
4580 Convert the input video to any of the formats in the list
4582 format=pix_fmts=yuv420p|yuv444p|yuv410p
4589 Convert the video to specified constant frame rate by duplicating or dropping
4590 frames as necessary.
4592 It accepts the following parameters:
4596 The desired output frame rate. The default is @code{25}.
4601 Possible values are:
4604 zero round towards 0
4608 round towards -infinity
4610 round towards +infinity
4614 The default is @code{near}.
4617 Assume the first PTS should be the given value, in seconds. This allows for
4618 padding/trimming at the start of stream. By default, no assumption is made
4619 about the first frame's expected PTS, so no padding or trimming is done.
4620 For example, this could be set to 0 to pad the beginning with duplicates of
4621 the first frame if a video stream starts after the audio stream or to trim any
4622 frames with a negative PTS.
4626 Alternatively, the options can be specified as a flat string:
4627 @var{fps}[:@var{round}].
4629 See also the @ref{setpts} filter.
4631 @subsection Examples
4635 A typical usage in order to set the fps to 25:
4641 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4643 fps=fps=film:round=near
4649 Pack two different video streams into a stereoscopic video, setting proper
4650 metadata on supported codecs. The two views should have the same size and
4651 framerate and processing will stop when the shorter video ends. Please note
4652 that you may conveniently adjust view properties with the @ref{scale} and
4655 It accepts the following parameters:
4659 The desired packing format. Supported values are:
4664 The views are next to each other (default).
4667 The views are on top of each other.
4670 The views are packed by line.
4673 The views are packed by column.
4676 The views are temporally interleaved.
4685 # Convert left and right views into a frame-sequential video
4686 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4688 # Convert views into a side-by-side video with the same output resolution as the input
4689 ffmpeg -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT
4694 Select one frame every N-th frame.
4696 This filter accepts the following option:
4699 Select frame after every @code{step} frames.
4700 Allowed values are positive integers higher than 0. Default value is @code{1}.
4706 Apply a frei0r effect to the input video.
4708 To enable the compilation of this filter, you need to install the frei0r
4709 header and configure FFmpeg with @code{--enable-frei0r}.
4711 It accepts the following parameters:
4716 The name of the frei0r effect to load. If the environment variable
4717 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
4718 directories specified by the colon-separated list in @env{FREIOR_PATH}.
4719 Otherwise, the standard frei0r paths are searched, in this order:
4720 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4721 @file{/usr/lib/frei0r-1/}.
4724 A '|'-separated list of parameters to pass to the frei0r effect.
4728 A frei0r effect parameter can be a boolean (its value is either
4729 "y" or "n"), a double, a color (specified as
4730 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
4731 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
4732 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
4733 @var{X} and @var{Y} are floating point numbers) and/or a string.
4735 The number and types of parameters depend on the loaded effect. If an
4736 effect parameter is not specified, the default value is set.
4738 @subsection Examples
4742 Apply the distort0r effect, setting the first two double parameters:
4744 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4748 Apply the colordistance effect, taking a color as the first parameter:
4750 frei0r=colordistance:0.2/0.3/0.4
4751 frei0r=colordistance:violet
4752 frei0r=colordistance:0x112233
4756 Apply the perspective effect, specifying the top left and top right image
4759 frei0r=perspective:0.2/0.2|0.8/0.2
4763 For more information, see
4764 @url{http://frei0r.dyne.org}
4768 The filter accepts the following options:
4772 Set the luminance expression.
4774 Set the chrominance blue expression.
4776 Set the chrominance red expression.
4778 Set the alpha expression.
4780 Set the red expression.
4782 Set the green expression.
4784 Set the blue expression.
4787 The colorspace is selected according to the specified options. If one
4788 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4789 options is specified, the filter will automatically select a YCbCr
4790 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4791 @option{blue_expr} options is specified, it will select an RGB
4794 If one of the chrominance expression is not defined, it falls back on the other
4795 one. If no alpha expression is specified it will evaluate to opaque value.
4796 If none of chrominance expressions are specified, they will evaluate
4797 to the luminance expression.
4799 The expressions can use the following variables and functions:
4803 The sequential number of the filtered frame, starting from @code{0}.
4807 The coordinates of the current sample.
4811 The width and height of the image.
4815 Width and height scale depending on the currently filtered plane. It is the
4816 ratio between the corresponding luma plane number of pixels and the current
4817 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4818 @code{0.5,0.5} for chroma planes.
4821 Time of the current frame, expressed in seconds.
4824 Return the value of the pixel at location (@var{x},@var{y}) of the current
4828 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4832 Return the value of the pixel at location (@var{x},@var{y}) of the
4833 blue-difference chroma plane. Return 0 if there is no such plane.
4836 Return the value of the pixel at location (@var{x},@var{y}) of the
4837 red-difference chroma plane. Return 0 if there is no such plane.
4842 Return the value of the pixel at location (@var{x},@var{y}) of the
4843 red/green/blue component. Return 0 if there is no such component.
4846 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4847 plane. Return 0 if there is no such plane.
4850 For functions, if @var{x} and @var{y} are outside the area, the value will be
4851 automatically clipped to the closer edge.
4853 @subsection Examples
4857 Flip the image horizontally:
4863 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4864 wavelength of 100 pixels:
4866 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4870 Generate a fancy enigmatic moving light:
4872 nullsrc=s=256x256,geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128
4876 Generate a quick emboss effect:
4878 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4882 Modify RGB components depending on pixel position:
4884 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4890 Fix the banding artifacts that are sometimes introduced into nearly flat
4891 regions by truncation to 8bit color depth.
4892 Interpolate the gradients that should go where the bands are, and
4895 It is designed for playback only. Do not use it prior to
4896 lossy compression, because compression tends to lose the dither and
4897 bring back the bands.
4899 It accepts the following parameters:
4904 The maximum amount by which the filter will change any one pixel. This is also
4905 the threshold for detecting nearly flat regions. Acceptable values range from
4906 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
4910 The neighborhood to fit the gradient to. A larger radius makes for smoother
4911 gradients, but also prevents the filter from modifying the pixels near detailed
4912 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
4913 values will be clipped to the valid range.
4917 Alternatively, the options can be specified as a flat string:
4918 @var{strength}[:@var{radius}]
4920 @subsection Examples
4924 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4930 Specify radius, omitting the strength (which will fall-back to the default
4941 Apply a Hald CLUT to a video stream.
4943 First input is the video stream to process, and second one is the Hald CLUT.
4944 The Hald CLUT input can be a simple picture or a complete video stream.
4946 The filter accepts the following options:
4950 Force termination when the shortest input terminates. Default is @code{0}.
4952 Continue applying the last CLUT after the end of the stream. A value of
4953 @code{0} disable the filter after the last frame of the CLUT is reached.
4954 Default is @code{1}.
4957 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4958 filters share the same internals).
4960 More information about the Hald CLUT can be found on Eskil Steenberg's website
4961 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4963 @subsection Workflow examples
4965 @subsubsection Hald CLUT video stream
4967 Generate an identity Hald CLUT stream altered with various effects:
4969 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process" -t 10 -c:v ffv1 clut.nut
4972 Note: make sure you use a lossless codec.
4974 Then use it with @code{haldclut} to apply it on some random stream:
4976 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4979 The Hald CLUT will be applied to the 10 first seconds (duration of
4980 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4981 to the remaining frames of the @code{mandelbrot} stream.
4983 @subsubsection Hald CLUT with preview
4985 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4986 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4987 biggest possible square starting at the top left of the picture. The remaining
4988 padding pixels (bottom or right) will be ignored. This area can be used to add
4989 a preview of the Hald CLUT.
4991 Typically, the following generated Hald CLUT will be supported by the
4992 @code{haldclut} filter:
4995 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
4996 pad=iw+320 [padded_clut];
4997 smptebars=s=320x256, split [a][b];
4998 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
4999 [main][b] overlay=W-320" -frames:v 1 clut.png
5002 It contains the original and a preview of the effect of the CLUT: SMPTE color
5003 bars are displayed on the right-top, and below the same color bars processed by
5006 Then, the effect of this Hald CLUT can be visualized with:
5008 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5013 Flip the input video horizontally.
5015 For example, to horizontally flip the input video with @command{ffmpeg}:
5017 ffmpeg -i in.avi -vf "hflip" out.avi
5021 This filter applies a global color histogram equalization on a
5024 It can be used to correct video that has a compressed range of pixel
5025 intensities. The filter redistributes the pixel intensities to
5026 equalize their distribution across the intensity range. It may be
5027 viewed as an "automatically adjusting contrast filter". This filter is
5028 useful only for correcting degraded or poorly captured source
5031 The filter accepts the following options:
5035 Determine the amount of equalization to be applied. As the strength
5036 is reduced, the distribution of pixel intensities more-and-more
5037 approaches that of the input frame. The value must be a float number
5038 in the range [0,1] and defaults to 0.200.
5041 Set the maximum intensity that can generated and scale the output
5042 values appropriately. The strength should be set as desired and then
5043 the intensity can be limited if needed to avoid washing-out. The value
5044 must be a float number in the range [0,1] and defaults to 0.210.
5047 Set the antibanding level. If enabled the filter will randomly vary
5048 the luminance of output pixels by a small amount to avoid banding of
5049 the histogram. Possible values are @code{none}, @code{weak} or
5050 @code{strong}. It defaults to @code{none}.
5055 Compute and draw a color distribution histogram for the input video.
5057 The computed histogram is a representation of the color component
5058 distribution in an image.
5060 The filter accepts the following options:
5066 It accepts the following values:
5069 Standard histogram that displays the color components distribution in an
5070 image. Displays color graph for each color component. Shows distribution of
5071 the Y, U, V, A or R, G, B components, depending on input format, in the
5072 current frame. Below each graph a color component scale meter is shown.
5075 Displays chroma values (U/V color placement) in a two dimensional
5076 graph (which is called a vectorscope). The brighter a pixel in the
5077 vectorscope, the more pixels of the input frame correspond to that pixel
5078 (i.e., more pixels have this chroma value). The V component is displayed on
5079 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5080 side being V = 255. The U component is displayed on the vertical (Y) axis,
5081 with the top representing U = 0 and the bottom representing U = 255.
5083 The position of a white pixel in the graph corresponds to the chroma value of
5084 a pixel of the input clip. The graph can therefore be used to read the hue
5085 (color flavor) and the saturation (the dominance of the hue in the color). As
5086 the hue of a color changes, it moves around the square. At the center of the
5087 square the saturation is zero, which means that the corresponding pixel has no
5088 color. If the amount of a specific color is increased (while leaving the other
5089 colors unchanged) the saturation increases, and the indicator moves towards
5090 the edge of the square.
5093 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5097 Per row/column color component graph. In row mode, the graph on the left side
5098 represents color component value 0 and the right side represents value = 255.
5099 In column mode, the top side represents color component value = 0 and bottom
5100 side represents value = 255.
5102 Default value is @code{levels}.
5105 Set height of level in @code{levels}. Default value is @code{200}.
5106 Allowed range is [50, 2048].
5109 Set height of color scale in @code{levels}. Default value is @code{12}.
5110 Allowed range is [0, 40].
5113 Set step for @code{waveform} mode. Smaller values are useful to find out how
5114 many values of the same luminance are distributed across input rows/columns.
5115 Default value is @code{10}. Allowed range is [1, 255].
5118 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5119 Default is @code{row}.
5121 @item waveform_mirror
5122 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5123 means mirrored. In mirrored mode, higher values will be represented on the left
5124 side for @code{row} mode and at the top for @code{column} mode. Default is
5125 @code{0} (unmirrored).
5128 Set display mode for @code{waveform} and @code{levels}.
5129 It accepts the following values:
5132 Display separate graph for the color components side by side in
5133 @code{row} waveform mode or one below the other in @code{column} waveform mode
5134 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5135 per color component graphs are placed below each other.
5137 Using this display mode in @code{waveform} histogram mode makes it easy to
5138 spot color casts in the highlights and shadows of an image, by comparing the
5139 contours of the top and the bottom graphs of each waveform. Since whites,
5140 grays, and blacks are characterized by exactly equal amounts of red, green,
5141 and blue, neutral areas of the picture should display three waveforms of
5142 roughly equal width/height. If not, the correction is easy to perform by
5143 making level adjustments the three waveforms.
5146 Presents information identical to that in the @code{parade}, except
5147 that the graphs representing color components are superimposed directly
5150 This display mode in @code{waveform} histogram mode makes it easier to spot
5151 relative differences or similarities in overlapping areas of the color
5152 components that are supposed to be identical, such as neutral whites, grays,
5155 Default is @code{parade}.
5158 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5159 Default is @code{linear}.
5162 @subsection Examples
5167 Calculate and draw histogram:
5169 ffplay -i input -vf histogram
5177 This is a high precision/quality 3d denoise filter. It aims to reduce
5178 image noise, producing smooth images and making still images really
5179 still. It should enhance compressibility.
5181 It accepts the following optional parameters:
5185 A non-negative floating point number which specifies spatial luma strength.
5188 @item chroma_spatial
5189 A non-negative floating point number which specifies spatial chroma strength.
5190 It defaults to 3.0*@var{luma_spatial}/4.0.
5193 A floating point number which specifies luma temporal strength. It defaults to
5194 6.0*@var{luma_spatial}/4.0.
5197 A floating point number which specifies chroma temporal strength. It defaults to
5198 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5203 Modify the hue and/or the saturation of the input.
5205 It accepts the following parameters:
5209 Specify the hue angle as a number of degrees. It accepts an expression,
5210 and defaults to "0".
5213 Specify the saturation in the [-10,10] range. It accepts an expression and
5217 Specify the hue angle as a number of radians. It accepts an
5218 expression, and defaults to "0".
5221 Specify the brightness in the [-10,10] range. It accepts an expression and
5225 @option{h} and @option{H} are mutually exclusive, and can't be
5226 specified at the same time.
5228 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5229 expressions containing the following constants:
5233 frame count of the input frame starting from 0
5236 presentation timestamp of the input frame expressed in time base units
5239 frame rate of the input video, NAN if the input frame rate is unknown
5242 timestamp expressed in seconds, NAN if the input timestamp is unknown
5245 time base of the input video
5248 @subsection Examples
5252 Set the hue to 90 degrees and the saturation to 1.0:
5258 Same command but expressing the hue in radians:
5264 Rotate hue and make the saturation swing between 0
5265 and 2 over a period of 1 second:
5267 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5271 Apply a 3 seconds saturation fade-in effect starting at 0:
5276 The general fade-in expression can be written as:
5278 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5282 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5284 hue="s=max(0\, min(1\, (8-t)/3))"
5287 The general fade-out expression can be written as:
5289 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5294 @subsection Commands
5296 This filter supports the following commands:
5302 Modify the hue and/or the saturation and/or brightness of the input video.
5303 The command accepts the same syntax of the corresponding option.
5305 If the specified expression is not valid, it is kept at its current
5311 Detect video interlacing type.
5313 This filter tries to detect if the input is interlaced or progressive,
5314 top or bottom field first.
5316 The filter accepts the following options:
5320 Set interlacing threshold.
5322 Set progressive threshold.
5327 Deinterleave or interleave fields.
5329 This filter allows one to process interlaced images fields without
5330 deinterlacing them. Deinterleaving splits the input frame into 2
5331 fields (so called half pictures). Odd lines are moved to the top
5332 half of the output image, even lines to the bottom half.
5333 You can process (filter) them independently and then re-interleave them.
5335 The filter accepts the following options:
5339 @item chroma_mode, c
5341 Available values for @var{luma_mode}, @var{chroma_mode} and
5342 @var{alpha_mode} are:
5348 @item deinterleave, d
5349 Deinterleave fields, placing one above the other.
5352 Interleave fields. Reverse the effect of deinterleaving.
5354 Default value is @code{none}.
5357 @item chroma_swap, cs
5358 @item alpha_swap, as
5359 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5364 Simple interlacing filter from progressive contents. This interleaves upper (or
5365 lower) lines from odd frames with lower (or upper) lines from even frames,
5366 halving the frame rate and preserving image height. A vertical lowpass filter
5367 is always applied in order to avoid twitter effects and reduce moiré patterns.
5370 Original Original New Frame
5371 Frame 'j' Frame 'j+1' (tff)
5372 ========== =========== ==================
5373 Line 0 --------------------> Frame 'j' Line 0
5374 Line 1 Line 1 ----> Frame 'j+1' Line 1
5375 Line 2 ---------------------> Frame 'j' Line 2
5376 Line 3 Line 3 ----> Frame 'j+1' Line 3
5378 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5381 It accepts the following optional parameters:
5385 This determines whether the interlaced frame is taken from the even
5386 (tff - default) or odd (bff) lines of the progressive frame.
5391 Deinterlace input video by applying Donald Graft's adaptive kernel
5392 deinterling. Work on interlaced parts of a video to produce
5395 The description of the accepted parameters follows.
5399 Set the threshold which affects the filter's tolerance when
5400 determining if a pixel line must be processed. It must be an integer
5401 in the range [0,255] and defaults to 10. A value of 0 will result in
5402 applying the process on every pixels.
5405 Paint pixels exceeding the threshold value to white if set to 1.
5409 Set the fields order. Swap fields if set to 1, leave fields alone if
5413 Enable additional sharpening if set to 1. Default is 0.
5416 Enable twoway sharpening if set to 1. Default is 0.
5419 @subsection Examples
5423 Apply default values:
5425 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5429 Enable additional sharpening:
5435 Paint processed pixels in white:
5444 Apply a 3D LUT to an input video.
5446 The filter accepts the following options:
5450 Set the 3D LUT file name.
5452 Currently supported formats:
5464 Select interpolation mode.
5466 Available values are:
5470 Use values from the nearest defined point.
5472 Interpolate values using the 8 points defining a cube.
5474 Interpolate values using a tetrahedron.
5478 @section lut, lutrgb, lutyuv
5480 Compute a look-up table for binding each pixel component input value
5481 to an output value, and apply it to the input video.
5483 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5484 to an RGB input video.
5486 These filters accept the following parameters:
5489 set first pixel component expression
5491 set second pixel component expression
5493 set third pixel component expression
5495 set fourth pixel component expression, corresponds to the alpha component
5498 set red component expression
5500 set green component expression
5502 set blue component expression
5504 alpha component expression
5507 set Y/luminance component expression
5509 set U/Cb component expression
5511 set V/Cr component expression
5514 Each of them specifies the expression to use for computing the lookup table for
5515 the corresponding pixel component values.
5517 The exact component associated to each of the @var{c*} options depends on the
5520 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5521 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5523 The expressions can contain the following constants and functions:
5528 The input width and height.
5531 The input value for the pixel component.
5534 The input value, clipped to the @var{minval}-@var{maxval} range.
5537 The maximum value for the pixel component.
5540 The minimum value for the pixel component.
5543 The negated value for the pixel component value, clipped to the
5544 @var{minval}-@var{maxval} range; it corresponds to the expression
5545 "maxval-clipval+minval".
5548 The computed value in @var{val}, clipped to the
5549 @var{minval}-@var{maxval} range.
5551 @item gammaval(gamma)
5552 The computed gamma correction value of the pixel component value,
5553 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5555 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5559 All expressions default to "val".
5561 @subsection Examples
5567 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5568 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5571 The above is the same as:
5573 lutrgb="r=negval:g=negval:b=negval"
5574 lutyuv="y=negval:u=negval:v=negval"
5584 Remove chroma components, turning the video into a graytone image:
5586 lutyuv="u=128:v=128"
5590 Apply a luma burning effect:
5596 Remove green and blue components:
5602 Set a constant alpha channel value on input:
5604 format=rgba,lutrgb=a="maxval-minval/2"
5608 Correct luminance gamma by a factor of 0.5:
5610 lutyuv=y=gammaval(0.5)
5614 Discard least significant bits of luma:
5616 lutyuv=y='bitand(val, 128+64+32)'
5620 @section mergeplanes
5622 Merge color channel components from several video streams.
5624 The filter accepts up to 4 input streams, and merge selected input
5625 planes to the output video.
5627 This filter accepts the following options:
5630 Set input to output plane mapping. Default is @code{0}.
5632 The mappings is specified as a bitmap. It should be specified as a
5633 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5634 mapping for the first plane of the output stream. 'A' sets the number of
5635 the input stream to use (from 0 to 3), and 'a' the plane number of the
5636 corresponding input to use (from 0 to 3). The rest of the mappings is
5637 similar, 'Bb' describes the mapping for the output stream second
5638 plane, 'Cc' describes the mapping for the output stream third plane and
5639 'Dd' describes the mapping for the output stream fourth plane.
5642 Set output pixel format. Default is @code{yuva444p}.
5645 @subsection Examples
5649 Merge three gray video streams of same width and height into single video stream:
5651 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5655 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5657 [a0][a1]mergeplanes=0x00010210:yuva444p
5661 Swap Y and A plane in yuva444p stream:
5663 format=yuva444p,mergeplanes=0x03010200:yuva444p
5667 Swap U and V plane in yuv420p stream:
5669 format=yuv420p,mergeplanes=0x000201:yuv420p
5673 Cast a rgb24 clip to yuv444p:
5675 format=rgb24,mergeplanes=0x000102:yuv444p
5681 Apply motion-compensation deinterlacing.
5683 It needs one field per frame as input and must thus be used together
5684 with yadif=1/3 or equivalent.
5686 This filter accepts the following options:
5689 Set the deinterlacing mode.
5691 It accepts one of the following values:
5696 use iterative motion estimation
5698 like @samp{slow}, but use multiple reference frames.
5700 Default value is @samp{fast}.
5703 Set the picture field parity assumed for the input video. It must be
5704 one of the following values:
5708 assume top field first
5710 assume bottom field first
5713 Default value is @samp{bff}.
5716 Set per-block quantization parameter (QP) used by the internal
5719 Higher values should result in a smoother motion vector field but less
5720 optimal individual vectors. Default value is 1.
5725 Apply an MPlayer filter to the input video.
5727 This filter provides a wrapper around some of the filters of
5730 This wrapper is considered experimental. Some of the wrapped filters
5731 may not work properly and we may drop support for them, as they will
5732 be implemented natively into FFmpeg. Thus you should avoid
5733 depending on them when writing portable scripts.
5735 The filter accepts the parameters:
5736 @var{filter_name}[:=]@var{filter_params}
5738 @var{filter_name} is the name of a supported MPlayer filter,
5739 @var{filter_params} is a string containing the parameters accepted by
5742 The list of the currently supported filters follows:
5753 The parameter syntax and behavior for the listed filters are the same
5754 of the corresponding MPlayer filters. For detailed instructions check
5755 the "VIDEO FILTERS" section in the MPlayer manual.
5757 @subsection Examples
5761 Adjust gamma, brightness, contrast:
5767 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5771 Drop frames that do not differ greatly from the previous frame in
5772 order to reduce frame rate.
5774 The main use of this filter is for very-low-bitrate encoding
5775 (e.g. streaming over dialup modem), but it could in theory be used for
5776 fixing movies that were inverse-telecined incorrectly.
5778 A description of the accepted options follows.
5782 Set the maximum number of consecutive frames which can be dropped (if
5783 positive), or the minimum interval between dropped frames (if
5784 negative). If the value is 0, the frame is dropped unregarding the
5785 number of previous sequentially dropped frames.
5792 Set the dropping threshold values.
5794 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5795 represent actual pixel value differences, so a threshold of 64
5796 corresponds to 1 unit of difference for each pixel, or the same spread
5797 out differently over the block.
5799 A frame is a candidate for dropping if no 8x8 blocks differ by more
5800 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5801 meaning the whole image) differ by more than a threshold of @option{lo}.
5803 Default value for @option{hi} is 64*12, default value for @option{lo} is
5804 64*5, and default value for @option{frac} is 0.33.
5812 It accepts an integer in input; if non-zero it negates the
5813 alpha component (if available). The default value in input is 0.
5817 Force libavfilter not to use any of the specified pixel formats for the
5818 input to the next filter.
5820 It accepts the following parameters:
5824 A '|'-separated list of pixel format names, such as
5825 apix_fmts=yuv420p|monow|rgb24".
5829 @subsection Examples
5833 Force libavfilter to use a format different from @var{yuv420p} for the
5834 input to the vflip filter:
5836 noformat=pix_fmts=yuv420p,vflip
5840 Convert the input video to any of the formats not contained in the list:
5842 noformat=yuv420p|yuv444p|yuv410p
5848 Add noise on video input frame.
5850 The filter accepts the following options:
5858 Set noise seed for specific pixel component or all pixel components in case
5859 of @var{all_seed}. Default value is @code{123457}.
5861 @item all_strength, alls
5862 @item c0_strength, c0s
5863 @item c1_strength, c1s
5864 @item c2_strength, c2s
5865 @item c3_strength, c3s
5866 Set noise strength for specific pixel component or all pixel components in case
5867 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5869 @item all_flags, allf
5874 Set pixel component flags or set flags for all components if @var{all_flags}.
5875 Available values for component flags are:
5878 averaged temporal noise (smoother)
5880 mix random noise with a (semi)regular pattern
5882 temporal noise (noise pattern changes between frames)
5884 uniform noise (gaussian otherwise)
5888 @subsection Examples
5890 Add temporal and uniform noise to input video:
5892 noise=alls=20:allf=t+u
5897 Pass the video source unchanged to the output.
5901 Apply a video transform using libopencv.
5903 To enable this filter, install the libopencv library and headers and
5904 configure FFmpeg with @code{--enable-libopencv}.
5906 It accepts the following parameters:
5911 The name of the libopencv filter to apply.
5914 The parameters to pass to the libopencv filter. If not specified, the default
5919 Refer to the official libopencv documentation for more precise
5921 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5923 Several libopencv filters are supported; see the following subsections.
5928 Dilate an image by using a specific structuring element.
5929 It corresponds to the libopencv function @code{cvDilate}.
5931 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5933 @var{struct_el} represents a structuring element, and has the syntax:
5934 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5936 @var{cols} and @var{rows} represent the number of columns and rows of
5937 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5938 point, and @var{shape} the shape for the structuring element. @var{shape}
5939 must be "rect", "cross", "ellipse", or "custom".
5941 If the value for @var{shape} is "custom", it must be followed by a
5942 string of the form "=@var{filename}". The file with name
5943 @var{filename} is assumed to represent a binary image, with each
5944 printable character corresponding to a bright pixel. When a custom
5945 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5946 or columns and rows of the read file are assumed instead.
5948 The default value for @var{struct_el} is "3x3+0x0/rect".
5950 @var{nb_iterations} specifies the number of times the transform is
5951 applied to the image, and defaults to 1.
5955 # Use the default values
5958 # Dilate using a structuring element with a 5x5 cross, iterating two times
5959 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5961 # Read the shape from the file diamond.shape, iterating two times.
5962 # The file diamond.shape may contain a pattern of characters like this
5968 # The specified columns and rows are ignored
5969 # but the anchor point coordinates are not
5970 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5975 Erode an image by using a specific structuring element.
5976 It corresponds to the libopencv function @code{cvErode}.
5978 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
5979 with the same syntax and semantics as the @ref{dilate} filter.
5983 Smooth the input video.
5985 The filter takes the following parameters:
5986 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5988 @var{type} is the type of smooth filter to apply, and must be one of
5989 the following values: "blur", "blur_no_scale", "median", "gaussian",
5990 or "bilateral". The default value is "gaussian".
5992 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
5993 depend on the smooth type. @var{param1} and
5994 @var{param2} accept integer positive values or 0. @var{param3} and
5995 @var{param4} accept floating point values.
5997 The default value for @var{param1} is 3. The default value for the
5998 other parameters is 0.
6000 These parameters correspond to the parameters assigned to the
6001 libopencv function @code{cvSmooth}.
6006 Overlay one video on top of another.
6008 It takes two inputs and has one output. The first input is the "main"
6009 video on which the second input is overlayed.
6011 It accepts the following parameters:
6013 A description of the accepted options follows.
6018 Set the expression for the x and y coordinates of the overlayed video
6019 on the main video. Default value is "0" for both expressions. In case
6020 the expression is invalid, it is set to a huge value (meaning that the
6021 overlay will not be displayed within the output visible area).
6024 The action to take when EOF is encountered on the secondary input; it accepts
6025 one of the following values:
6029 Repeat the last frame (the default).
6033 Pass the main input through.
6037 Set when the expressions for @option{x}, and @option{y} are evaluated.
6039 It accepts the following values:
6042 only evaluate expressions once during the filter initialization or
6043 when a command is processed
6046 evaluate expressions for each incoming frame
6049 Default value is @samp{frame}.
6052 If set to 1, force the output to terminate when the shortest input
6053 terminates. Default value is 0.
6056 Set the format for the output video.
6058 It accepts the following values:
6073 Default value is @samp{yuv420}.
6075 @item rgb @emph{(deprecated)}
6076 If set to 1, force the filter to accept inputs in the RGB
6077 color space. Default value is 0. This option is deprecated, use
6078 @option{format} instead.
6081 If set to 1, force the filter to draw the last overlay frame over the
6082 main input until the end of the stream. A value of 0 disables this
6083 behavior. Default value is 1.
6086 The @option{x}, and @option{y} expressions can contain the following
6092 The main input width and height.
6096 The overlay input width and height.
6100 The computed values for @var{x} and @var{y}. They are evaluated for
6105 horizontal and vertical chroma subsample values of the output
6106 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6110 the number of input frame, starting from 0
6113 the position in the file of the input frame, NAN if unknown
6116 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6120 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6121 when evaluation is done @emph{per frame}, and will evaluate to NAN
6122 when @option{eval} is set to @samp{init}.
6124 Be aware that frames are taken from each input video in timestamp
6125 order, hence, if their initial timestamps differ, it is a good idea
6126 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6127 have them begin in the same zero timestamp, as the example for
6128 the @var{movie} filter does.
6130 You can chain together more overlays but you should test the
6131 efficiency of such approach.
6133 @subsection Commands
6135 This filter supports the following commands:
6139 Modify the x and y of the overlay input.
6140 The command accepts the same syntax of the corresponding option.
6142 If the specified expression is not valid, it is kept at its current
6146 @subsection Examples
6150 Draw the overlay at 10 pixels from the bottom right corner of the main
6153 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6156 Using named options the example above becomes:
6158 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6162 Insert a transparent PNG logo in the bottom left corner of the input,
6163 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6165 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6169 Insert 2 different transparent PNG logos (second logo on bottom
6170 right corner) using the @command{ffmpeg} tool:
6172 ffmpeg -i input -i logo1 -i logo2 -filter_complex 'overlay=x=10:y=H-h-10,overlay=x=W-w-10:y=H-h-10' output
6176 Add a transparent color layer on top of the main video; @code{WxH}
6177 must specify the size of the main input to the overlay filter:
6179 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6183 Play an original video and a filtered version (here with the deshake
6184 filter) side by side using the @command{ffplay} tool:
6186 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6189 The above command is the same as:
6191 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6195 Make a sliding overlay appearing from the left to the right top part of the
6196 screen starting since time 2:
6198 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6202 Compose output by putting two input videos side to side:
6204 ffmpeg -i left.avi -i right.avi -filter_complex "
6205 nullsrc=size=200x100 [background];
6206 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6207 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6208 [background][left] overlay=shortest=1 [background+left];
6209 [background+left][right] overlay=shortest=1:x=100 [left+right]
6214 Mask 10-20 seconds of a video by applying the delogo filter to a section
6216 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6217 -vf '[in]split[split_main][split_delogo];[split_delogo]trim=start=360:end=371,delogo=0:0:640:480[delogoed];[split_main][delogoed]overlay=eof_action=pass[out]'
6222 Chain several overlays in cascade:
6224 nullsrc=s=200x200 [bg];
6225 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6226 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6227 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6228 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6229 [in3] null, [mid2] overlay=100:100 [out0]
6236 Apply Overcomplete Wavelet denoiser.
6238 The filter accepts the following options:
6244 Larger depth values will denoise lower frequency components more, but
6245 slow down filtering.
6247 Must be an int in the range 8-16, default is @code{8}.
6249 @item luma_strength, ls
6252 Must be a double value in the range 0-1000, default is @code{1.0}.
6254 @item chroma_strength, cs
6255 Set chroma strength.
6257 Must be a double value in the range 0-1000, default is @code{1.0}.
6262 Add paddings to the input image, and place the original input at the
6263 provided @var{x}, @var{y} coordinates.
6265 It accepts the following parameters:
6270 Specify an expression for the size of the output image with the
6271 paddings added. If the value for @var{width} or @var{height} is 0, the
6272 corresponding input size is used for the output.
6274 The @var{width} expression can reference the value set by the
6275 @var{height} expression, and vice versa.
6277 The default value of @var{width} and @var{height} is 0.
6281 Specify the offsets to place the input image at within the padded area,
6282 with respect to the top/left border of the output image.
6284 The @var{x} expression can reference the value set by the @var{y}
6285 expression, and vice versa.
6287 The default value of @var{x} and @var{y} is 0.
6290 Specify the color of the padded area. For the syntax of this option,
6291 check the "Color" section in the ffmpeg-utils manual.
6293 The default value of @var{color} is "black".
6296 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6297 options are expressions containing the following constants:
6302 The input video width and height.
6306 These are the same as @var{in_w} and @var{in_h}.
6310 The output width and height (the size of the padded area), as
6311 specified by the @var{width} and @var{height} expressions.
6315 These are the same as @var{out_w} and @var{out_h}.
6319 The x and y offsets as specified by the @var{x} and @var{y}
6320 expressions, or NAN if not yet specified.
6323 same as @var{iw} / @var{ih}
6326 input sample aspect ratio
6329 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6333 The horizontal and vertical chroma subsample values. For example for the
6334 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6337 @subsection Examples
6341 Add paddings with the color "violet" to the input video. The output video
6342 size is 640x480, and the top-left corner of the input video is placed at
6345 pad=640:480:0:40:violet
6348 The example above is equivalent to the following command:
6350 pad=width=640:height=480:x=0:y=40:color=violet
6354 Pad the input to get an output with dimensions increased by 3/2,
6355 and put the input video at the center of the padded area:
6357 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6361 Pad the input to get a squared output with size equal to the maximum
6362 value between the input width and height, and put the input video at
6363 the center of the padded area:
6365 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6369 Pad the input to get a final w/h ratio of 16:9:
6371 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6375 In case of anamorphic video, in order to set the output display aspect
6376 correctly, it is necessary to use @var{sar} in the expression,
6377 according to the relation:
6379 (ih * X / ih) * sar = output_dar
6380 X = output_dar / sar
6383 Thus the previous example needs to be modified to:
6385 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6389 Double the output size and put the input video in the bottom-right
6390 corner of the output padded area:
6392 pad="2*iw:2*ih:ow-iw:oh-ih"
6396 @section perspective
6398 Correct perspective of video not recorded perpendicular to the screen.
6400 A description of the accepted parameters follows.
6411 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6412 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6414 The expressions can use the following variables:
6419 the width and height of video frame.
6423 Set interpolation for perspective correction.
6425 It accepts the following values:
6431 Default value is @samp{linear}.
6436 Delay interlaced video by one field time so that the field order changes.
6438 The intended use is to fix PAL movies that have been captured with the
6439 opposite field order to the film-to-video transfer.
6441 A description of the accepted parameters follows.
6447 It accepts the following values:
6450 Capture field order top-first, transfer bottom-first.
6451 Filter will delay the bottom field.
6454 Capture field order bottom-first, transfer top-first.
6455 Filter will delay the top field.
6458 Capture and transfer with the same field order. This mode only exists
6459 for the documentation of the other options to refer to, but if you
6460 actually select it, the filter will faithfully do nothing.
6463 Capture field order determined automatically by field flags, transfer
6465 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6466 basis using field flags. If no field information is available,
6467 then this works just like @samp{u}.
6470 Capture unknown or varying, transfer opposite.
6471 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6472 analyzing the images and selecting the alternative that produces best
6473 match between the fields.
6476 Capture top-first, transfer unknown or varying.
6477 Filter selects among @samp{t} and @samp{p} using image analysis.
6480 Capture bottom-first, transfer unknown or varying.
6481 Filter selects among @samp{b} and @samp{p} using image analysis.
6484 Capture determined by field flags, transfer unknown or varying.
6485 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6486 image analysis. If no field information is available, then this works just
6487 like @samp{U}. This is the default mode.
6490 Both capture and transfer unknown or varying.
6491 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6495 @section pixdesctest
6497 Pixel format descriptor test filter, mainly useful for internal
6498 testing. The output video should be equal to the input video.
6502 format=monow, pixdesctest
6505 can be used to test the monowhite pixel format descriptor definition.
6509 Enable the specified chain of postprocessing subfilters using libpostproc. This
6510 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6511 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6512 Each subfilter and some options have a short and a long name that can be used
6513 interchangeably, i.e. dr/dering are the same.
6515 The filters accept the following options:
6519 Set postprocessing subfilters string.
6522 All subfilters share common options to determine their scope:
6526 Honor the quality commands for this subfilter.
6529 Do chrominance filtering, too (default).
6532 Do luminance filtering only (no chrominance).
6535 Do chrominance filtering only (no luminance).
6538 These options can be appended after the subfilter name, separated by a '|'.
6540 Available subfilters are:
6543 @item hb/hdeblock[|difference[|flatness]]
6544 Horizontal deblocking filter
6547 Difference factor where higher values mean more deblocking (default: @code{32}).
6549 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6552 @item vb/vdeblock[|difference[|flatness]]
6553 Vertical deblocking filter
6556 Difference factor where higher values mean more deblocking (default: @code{32}).
6558 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6561 @item ha/hadeblock[|difference[|flatness]]
6562 Accurate horizontal deblocking filter
6565 Difference factor where higher values mean more deblocking (default: @code{32}).
6567 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6570 @item va/vadeblock[|difference[|flatness]]
6571 Accurate vertical deblocking filter
6574 Difference factor where higher values mean more deblocking (default: @code{32}).
6576 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6580 The horizontal and vertical deblocking filters share the difference and
6581 flatness values so you cannot set different horizontal and vertical
6586 Experimental horizontal deblocking filter
6589 Experimental vertical deblocking filter
6594 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6597 larger -> stronger filtering
6599 larger -> stronger filtering
6601 larger -> stronger filtering
6604 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6607 Stretch luminance to @code{0-255}.
6610 @item lb/linblenddeint
6611 Linear blend deinterlacing filter that deinterlaces the given block by
6612 filtering all lines with a @code{(1 2 1)} filter.
6614 @item li/linipoldeint
6615 Linear interpolating deinterlacing filter that deinterlaces the given block by
6616 linearly interpolating every second line.
6618 @item ci/cubicipoldeint
6619 Cubic interpolating deinterlacing filter deinterlaces the given block by
6620 cubically interpolating every second line.
6622 @item md/mediandeint
6623 Median deinterlacing filter that deinterlaces the given block by applying a
6624 median filter to every second line.
6626 @item fd/ffmpegdeint
6627 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6628 second line with a @code{(-1 4 2 4 -1)} filter.
6631 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6632 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6634 @item fq/forceQuant[|quantizer]
6635 Overrides the quantizer table from the input with the constant quantizer you
6643 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6646 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6649 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6652 @subsection Examples
6656 Apply horizontal and vertical deblocking, deringing and automatic
6657 brightness/contrast:
6663 Apply default filters without brightness/contrast correction:
6669 Apply default filters and temporal denoiser:
6671 pp=default/tmpnoise|1|2|3
6675 Apply deblocking on luminance only, and switch vertical deblocking on or off
6676 automatically depending on available CPU time:
6684 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6685 Ratio) between two input videos.
6687 This filter takes in input two input videos, the first input is
6688 considered the "main" source and is passed unchanged to the
6689 output. The second input is used as a "reference" video for computing
6692 Both video inputs must have the same resolution and pixel format for
6693 this filter to work correctly. Also it assumes that both inputs
6694 have the same number of frames, which are compared one by one.
6696 The obtained average PSNR is printed through the logging system.
6698 The filter stores the accumulated MSE (mean squared error) of each
6699 frame, and at the end of the processing it is averaged across all frames
6700 equally, and the following formula is applied to obtain the PSNR:
6703 PSNR = 10*log10(MAX^2/MSE)
6706 Where MAX is the average of the maximum values of each component of the
6709 The description of the accepted parameters follows.
6713 If specified the filter will use the named file to save the PSNR of
6714 each individual frame.
6717 The file printed if @var{stats_file} is selected, contains a sequence of
6718 key/value pairs of the form @var{key}:@var{value} for each compared
6721 A description of each shown parameter follows:
6725 sequential number of the input frame, starting from 1
6728 Mean Square Error pixel-by-pixel average difference of the compared
6729 frames, averaged over all the image components.
6731 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6732 Mean Square Error pixel-by-pixel average difference of the compared
6733 frames for the component specified by the suffix.
6735 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6736 Peak Signal to Noise ratio of the compared frames for the component
6737 specified by the suffix.
6742 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6743 [main][ref] psnr="stats_file=stats.log" [out]
6746 On this example the input file being processed is compared with the
6747 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6748 is stored in @file{stats.log}.
6753 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6754 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6757 The pullup filter is designed to take advantage of future context in making
6758 its decisions. This filter is stateless in the sense that it does not lock
6759 onto a pattern to follow, but it instead looks forward to the following
6760 fields in order to identify matches and rebuild progressive frames.
6762 To produce content with an even framerate, insert the fps filter after
6763 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6764 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6766 The filter accepts the following options:
6773 These options set the amount of "junk" to ignore at the left, right, top, and
6774 bottom of the image, respectively. Left and right are in units of 8 pixels,
6775 while top and bottom are in units of 2 lines.
6776 The default is 8 pixels on each side.
6779 Set the strict breaks. Setting this option to 1 will reduce the chances of
6780 filter generating an occasional mismatched frame, but it may also cause an
6781 excessive number of frames to be dropped during high motion sequences.
6782 Conversely, setting it to -1 will make filter match fields more easily.
6783 This may help processing of video where there is slight blurring between
6784 the fields, but may also cause there to be interlaced frames in the output.
6785 Default value is @code{0}.
6788 Set the metric plane to use. It accepts the following values:
6794 Use chroma blue plane.
6797 Use chroma red plane.
6800 This option may be set to use chroma plane instead of the default luma plane
6801 for doing filter's computations. This may improve accuracy on very clean
6802 source material, but more likely will decrease accuracy, especially if there
6803 is chroma noise (rainbow effect) or any grayscale video.
6804 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6805 load and make pullup usable in realtime on slow machines.
6808 For best results (without duplicated frames in the output file) it is
6809 necessary to change the output frame rate. For example, to inverse
6810 telecine NTSC input:
6812 ffmpeg -i input -vf pullup -r 24000/1001 ...
6817 Suppress a TV station logo, using an image file to determine which
6818 pixels comprise the logo. It works by filling in the pixels that
6819 comprise the logo with neighboring pixels.
6821 The filter accepts the following options:
6825 Set the filter bitmap file, which can be any image format supported by
6826 libavformat. The width and height of the image file must match those of the
6827 video stream being processed.
6830 Pixels in the provided bitmap image with a value of zero are not
6831 considered part of the logo, non-zero pixels are considered part of
6832 the logo. If you use white (255) for the logo and black (0) for the
6833 rest, you will be safe. For making the filter bitmap, it is
6834 recommended to take a screen capture of a black frame with the logo
6835 visible, and then using a threshold filter followed by the erode
6836 filter once or twice.
6838 If needed, little splotches can be fixed manually. Remember that if
6839 logo pixels are not covered, the filter quality will be much
6840 reduced. Marking too many pixels as part of the logo does not hurt as
6841 much, but it will increase the amount of blurring needed to cover over
6842 the image and will destroy more information than necessary, and extra
6843 pixels will slow things down on a large logo.
6847 Rotate video by an arbitrary angle expressed in radians.
6849 The filter accepts the following options:
6851 A description of the optional parameters follows.
6854 Set an expression for the angle by which to rotate the input video
6855 clockwise, expressed as a number of radians. A negative value will
6856 result in a counter-clockwise rotation. By default it is set to "0".
6858 This expression is evaluated for each frame.
6861 Set the output width expression, default value is "iw".
6862 This expression is evaluated just once during configuration.
6865 Set the output height expression, default value is "ih".
6866 This expression is evaluated just once during configuration.
6869 Enable bilinear interpolation if set to 1, a value of 0 disables
6870 it. Default value is 1.
6873 Set the color used to fill the output area not covered by the rotated
6874 image. For the generalsyntax of this option, check the "Color" section in the
6875 ffmpeg-utils manual. If the special value "none" is selected then no
6876 background is printed (useful for example if the background is never shown).
6878 Default value is "black".
6881 The expressions for the angle and the output size can contain the
6882 following constants and functions:
6886 sequential number of the input frame, starting from 0. It is always NAN
6887 before the first frame is filtered.
6890 time in seconds of the input frame, it is set to 0 when the filter is
6891 configured. It is always NAN before the first frame is filtered.
6895 horizontal and vertical chroma subsample values. For example for the
6896 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6900 the input video width and height
6904 the output width and height, that is the size of the padded area as
6905 specified by the @var{width} and @var{height} expressions
6909 the minimal width/height required for completely containing the input
6910 video rotated by @var{a} radians.
6912 These are only available when computing the @option{out_w} and
6913 @option{out_h} expressions.
6916 @subsection Examples
6920 Rotate the input by PI/6 radians clockwise:
6926 Rotate the input by PI/6 radians counter-clockwise:
6932 Rotate the input by 45 degrees clockwise:
6938 Apply a constant rotation with period T, starting from an angle of PI/3:
6940 rotate=PI/3+2*PI*t/T
6944 Make the input video rotation oscillating with a period of T
6945 seconds and an amplitude of A radians:
6947 rotate=A*sin(2*PI/T*t)
6951 Rotate the video, output size is chosen so that the whole rotating
6952 input video is always completely contained in the output:
6954 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
6958 Rotate the video, reduce the output size so that no background is ever
6961 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
6965 @subsection Commands
6967 The filter supports the following commands:
6971 Set the angle expression.
6972 The command accepts the same syntax of the corresponding option.
6974 If the specified expression is not valid, it is kept at its current
6980 Apply Shape Adaptive Blur.
6982 The filter accepts the following options:
6985 @item luma_radius, lr
6986 Set luma blur filter strength, must be a value in range 0.1-4.0, default
6987 value is 1.0. A greater value will result in a more blurred image, and
6988 in slower processing.
6990 @item luma_pre_filter_radius, lpfr
6991 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
6994 @item luma_strength, ls
6995 Set luma maximum difference between pixels to still be considered, must
6996 be a value in the 0.1-100.0 range, default value is 1.0.
6998 @item chroma_radius, cr
6999 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7000 greater value will result in a more blurred image, and in slower
7003 @item chroma_pre_filter_radius, cpfr
7004 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7006 @item chroma_strength, cs
7007 Set chroma maximum difference between pixels to still be considered,
7008 must be a value in the 0.1-100.0 range.
7011 Each chroma option value, if not explicitly specified, is set to the
7012 corresponding luma option value.
7017 Scale (resize) the input video, using the libswscale library.
7019 The scale filter forces the output display aspect ratio to be the same
7020 of the input, by changing the output sample aspect ratio.
7022 If the input image format is different from the format requested by
7023 the next filter, the scale filter will convert the input to the
7027 The filter accepts the following options, or any of the options
7028 supported by the libswscale scaler.
7030 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7031 the complete list of scaler options.
7036 Set the output video dimension expression. Default value is the input
7039 If the value is 0, the input width is used for the output.
7041 If one of the values is -1, the scale filter will use a value that
7042 maintains the aspect ratio of the input image, calculated from the
7043 other specified dimension. If both of them are -1, the input size is
7046 If one of the values is -n with n > 1, the scale filter will also use a value
7047 that maintains the aspect ratio of the input image, calculated from the other
7048 specified dimension. After that it will, however, make sure that the calculated
7049 dimension is divisible by n and adjust the value if necessary.
7051 See below for the list of accepted constants for use in the dimension
7055 Set the interlacing mode. It accepts the following values:
7059 Force interlaced aware scaling.
7062 Do not apply interlaced scaling.
7065 Select interlaced aware scaling depending on whether the source frames
7066 are flagged as interlaced or not.
7069 Default value is @samp{0}.
7072 Set libswscale scaling flags. See
7073 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7074 complete list of values. If not explicitly specified the filter applies
7078 Set the video size. For the syntax of this option, check the "Video size"
7079 section in the ffmpeg-utils manual.
7081 @item in_color_matrix
7082 @item out_color_matrix
7083 Set in/output YCbCr color space type.
7085 This allows the autodetected value to be overridden as well as allows forcing
7086 a specific value used for the output and encoder.
7088 If not specified, the color space type depends on the pixel format.
7094 Choose automatically.
7097 Format conforming to International Telecommunication Union (ITU)
7098 Recommendation BT.709.
7101 Set color space conforming to the United States Federal Communications
7102 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7105 Set color space conforming to:
7109 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7112 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7115 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7120 Set color space conforming to SMPTE ST 240:1999.
7125 Set in/output YCbCr sample range.
7127 This allows the autodetected value to be overridden as well as allows forcing
7128 a specific value used for the output and encoder. If not specified, the
7129 range depends on the pixel format. Possible values:
7133 Choose automatically.
7136 Set full range (0-255 in case of 8-bit luma).
7139 Set "MPEG" range (16-235 in case of 8-bit luma).
7142 @item force_original_aspect_ratio
7143 Enable decreasing or increasing output video width or height if necessary to
7144 keep the original aspect ratio. Possible values:
7148 Scale the video as specified and disable this feature.
7151 The output video dimensions will automatically be decreased if needed.
7154 The output video dimensions will automatically be increased if needed.
7158 One useful instance of this option is that when you know a specific device's
7159 maximum allowed resolution, you can use this to limit the output video to
7160 that, while retaining the aspect ratio. For example, device A allows
7161 1280x720 playback, and your video is 1920x800. Using this option (set it to
7162 decrease) and specifying 1280x720 to the command line makes the output
7165 Please note that this is a different thing than specifying -1 for @option{w}
7166 or @option{h}, you still need to specify the output resolution for this option
7171 The values of the @option{w} and @option{h} options are expressions
7172 containing the following constants:
7177 The input width and height
7181 These are the same as @var{in_w} and @var{in_h}.
7185 The output (scaled) width and height
7189 These are the same as @var{out_w} and @var{out_h}
7192 The same as @var{iw} / @var{ih}
7195 input sample aspect ratio
7198 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7202 horizontal and vertical input chroma subsample values. For example for the
7203 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7207 horizontal and vertical output chroma subsample values. For example for the
7208 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7211 @subsection Examples
7215 Scale the input video to a size of 200x100
7220 This is equivalent to:
7231 Specify a size abbreviation for the output size:
7236 which can also be written as:
7242 Scale the input to 2x:
7248 The above is the same as:
7254 Scale the input to 2x with forced interlaced scaling:
7256 scale=2*iw:2*ih:interl=1
7260 Scale the input to half size:
7266 Increase the width, and set the height to the same size:
7279 Increase the height, and set the width to 3/2 of the height:
7281 scale=w=3/2*oh:h=3/5*ih
7285 Increase the size, making the size a multiple of the chroma
7288 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7292 Increase the width to a maximum of 500 pixels,
7293 keeping the same aspect ratio as the input:
7295 scale=w='min(500\, iw*3/2):h=-1'
7299 @section separatefields
7301 The @code{separatefields} takes a frame-based video input and splits
7302 each frame into its components fields, producing a new half height clip
7303 with twice the frame rate and twice the frame count.
7305 This filter use field-dominance information in frame to decide which
7306 of each pair of fields to place first in the output.
7307 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7309 @section setdar, setsar
7311 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7314 This is done by changing the specified Sample (aka Pixel) Aspect
7315 Ratio, according to the following equation:
7317 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7320 Keep in mind that the @code{setdar} filter does not modify the pixel
7321 dimensions of the video frame. Also, the display aspect ratio set by
7322 this filter may be changed by later filters in the filterchain,
7323 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7326 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7327 the filter output video.
7329 Note that as a consequence of the application of this filter, the
7330 output display aspect ratio will change according to the equation
7333 Keep in mind that the sample aspect ratio set by the @code{setsar}
7334 filter may be changed by later filters in the filterchain, e.g. if
7335 another "setsar" or a "setdar" filter is applied.
7337 It accepts the following parameters:
7340 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7341 Set the aspect ratio used by the filter.
7343 The parameter can be a floating point number string, an expression, or
7344 a string of the form @var{num}:@var{den}, where @var{num} and
7345 @var{den} are the numerator and denominator of the aspect ratio. If
7346 the parameter is not specified, it is assumed the value "0".
7347 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7351 Set the maximum integer value to use for expressing numerator and
7352 denominator when reducing the expressed aspect ratio to a rational.
7353 Default value is @code{100}.
7357 The parameter @var{sar} is an expression containing
7358 the following constants:
7362 These are approximated values for the mathematical constants e
7363 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7366 The input width and height.
7369 These are the same as @var{w} / @var{h}.
7372 The input sample aspect ratio.
7375 The input display aspect ratio. It is the same as
7376 (@var{w} / @var{h}) * @var{sar}.
7379 Horizontal and vertical chroma subsample values. For example, for the
7380 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7383 @subsection Examples
7388 To change the display aspect ratio to 16:9, specify one of the following:
7396 To change the sample aspect ratio to 10:11, specify:
7402 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7403 1000 in the aspect ratio reduction, use the command:
7405 setdar=ratio=16/9:max=1000
7413 Force field for the output video frame.
7415 The @code{setfield} filter marks the interlace type field for the
7416 output frames. It does not change the input frame, but only sets the
7417 corresponding property, which affects how the frame is treated by
7418 following filters (e.g. @code{fieldorder} or @code{yadif}).
7420 The filter accepts the following options:
7425 Available values are:
7429 Keep the same field property.
7432 Mark the frame as bottom-field-first.
7435 Mark the frame as top-field-first.
7438 Mark the frame as progressive.
7444 Show a line containing various information for each input video frame.
7445 The input video is not modified.
7447 The shown line contains a sequence of key/value pairs of the form
7448 @var{key}:@var{value}.
7450 It accepts the following parameters:
7454 The (sequential) number of the input frame, starting from 0.
7457 The Presentation TimeStamp of the input frame, expressed as a number of
7458 time base units. The time base unit depends on the filter input pad.
7461 The Presentation TimeStamp of the input frame, expressed as a number of
7465 The position of the frame in the input stream, or -1 if this information is
7466 unavailable and/or meaningless (for example in case of synthetic video).
7469 The pixel format name.
7472 The sample aspect ratio of the input frame, expressed in the form
7473 @var{num}/@var{den}.
7476 The size of the input frame. For the syntax of this option, check the "Video size"
7477 section in the ffmpeg-utils manual.
7480 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7481 for bottom field first).
7484 This is 1 if the frame is a key frame, 0 otherwise.
7487 The picture type of the input frame ("I" for an I-frame, "P" for a
7488 P-frame, "B" for a B-frame, or "?" for an unknown type).
7489 Also refer to the documentation of the @code{AVPictureType} enum and of
7490 the @code{av_get_picture_type_char} function defined in
7491 @file{libavutil/avutil.h}.
7494 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7496 @item plane_checksum
7497 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7498 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7501 @section shuffleplanes
7503 Reorder and/or duplicate video planes.
7505 It accepts the following parameters:
7510 The index of the input plane to be used as the first output plane.
7513 The index of the input plane to be used as the second output plane.
7516 The index of the input plane to be used as the third output plane.
7519 The index of the input plane to be used as the fourth output plane.
7523 The first plane has the index 0. The default is to keep the input unchanged.
7525 Swap the second and third planes of the input:
7527 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7533 Blur the input video without impacting the outlines.
7535 It accepts the following options:
7538 @item luma_radius, lr
7539 Set the luma radius. The option value must be a float number in
7540 the range [0.1,5.0] that specifies the variance of the gaussian filter
7541 used to blur the image (slower if larger). Default value is 1.0.
7543 @item luma_strength, ls
7544 Set the luma strength. The option value must be a float number
7545 in the range [-1.0,1.0] that configures the blurring. A value included
7546 in [0.0,1.0] will blur the image whereas a value included in
7547 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7549 @item luma_threshold, lt
7550 Set the luma threshold used as a coefficient to determine
7551 whether a pixel should be blurred or not. The option value must be an
7552 integer in the range [-30,30]. A value of 0 will filter all the image,
7553 a value included in [0,30] will filter flat areas and a value included
7554 in [-30,0] will filter edges. Default value is 0.
7556 @item chroma_radius, cr
7557 Set the chroma radius. The option value must be a float number in
7558 the range [0.1,5.0] that specifies the variance of the gaussian filter
7559 used to blur the image (slower if larger). Default value is 1.0.
7561 @item chroma_strength, cs
7562 Set the chroma strength. The option value must be a float number
7563 in the range [-1.0,1.0] that configures the blurring. A value included
7564 in [0.0,1.0] will blur the image whereas a value included in
7565 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7567 @item chroma_threshold, ct
7568 Set the chroma threshold used as a coefficient to determine
7569 whether a pixel should be blurred or not. The option value must be an
7570 integer in the range [-30,30]. A value of 0 will filter all the image,
7571 a value included in [0,30] will filter flat areas and a value included
7572 in [-30,0] will filter edges. Default value is 0.
7575 If a chroma option is not explicitly set, the corresponding luma value
7580 Convert between different stereoscopic image formats.
7582 The filters accept the following options:
7586 Set stereoscopic image format of input.
7588 Available values for input image formats are:
7591 side by side parallel (left eye left, right eye right)
7594 side by side crosseye (right eye left, left eye right)
7597 side by side parallel with half width resolution
7598 (left eye left, right eye right)
7601 side by side crosseye with half width resolution
7602 (right eye left, left eye right)
7605 above-below (left eye above, right eye below)
7608 above-below (right eye above, left eye below)
7611 above-below with half height resolution
7612 (left eye above, right eye below)
7615 above-below with half height resolution
7616 (right eye above, left eye below)
7619 alternating frames (left eye first, right eye second)
7622 alternating frames (right eye first, left eye second)
7624 Default value is @samp{sbsl}.
7628 Set stereoscopic image format of output.
7630 Available values for output image formats are all the input formats as well as:
7633 anaglyph red/blue gray
7634 (red filter on left eye, blue filter on right eye)
7637 anaglyph red/green gray
7638 (red filter on left eye, green filter on right eye)
7641 anaglyph red/cyan gray
7642 (red filter on left eye, cyan filter on right eye)
7645 anaglyph red/cyan half colored
7646 (red filter on left eye, cyan filter on right eye)
7649 anaglyph red/cyan color
7650 (red filter on left eye, cyan filter on right eye)
7653 anaglyph red/cyan color optimized with the least squares projection of dubois
7654 (red filter on left eye, cyan filter on right eye)
7657 anaglyph green/magenta gray
7658 (green filter on left eye, magenta filter on right eye)
7661 anaglyph green/magenta half colored
7662 (green filter on left eye, magenta filter on right eye)
7665 anaglyph green/magenta colored
7666 (green filter on left eye, magenta filter on right eye)
7669 anaglyph green/magenta color optimized with the least squares projection of dubois
7670 (green filter on left eye, magenta filter on right eye)
7673 anaglyph yellow/blue gray
7674 (yellow filter on left eye, blue filter on right eye)
7677 anaglyph yellow/blue half colored
7678 (yellow filter on left eye, blue filter on right eye)
7681 anaglyph yellow/blue colored
7682 (yellow filter on left eye, blue filter on right eye)
7685 anaglyph yellow/blue color optimized with the least squares projection of dubois
7686 (yellow filter on left eye, blue filter on right eye)
7689 interleaved rows (left eye has top row, right eye starts on next row)
7692 interleaved rows (right eye has top row, left eye starts on next row)
7695 mono output (left eye only)
7698 mono output (right eye only)
7701 Default value is @samp{arcd}.
7704 @subsection Examples
7708 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7714 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7722 Apply a simple postprocessing filter that compresses and decompresses the image
7723 at several (or - in the case of @option{quality} level @code{6} - all) shifts
7724 and average the results.
7726 The filter accepts the following options:
7730 Set quality. This option defines the number of levels for averaging. It accepts
7731 an integer in the range 0-6. If set to @code{0}, the filter will have no
7732 effect. A value of @code{6} means the higher quality. For each increment of
7733 that value the speed drops by a factor of approximately 2. Default value is
7737 Force a constant quantization parameter. If not set, the filter will use the QP
7738 from the video stream (if available).
7741 Set thresholding mode. Available modes are:
7745 Set hard thresholding (default).
7747 Set soft thresholding (better de-ringing effect, but likely blurrier).
7751 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7752 option may cause flicker since the B-Frames have often larger QP. Default is
7753 @code{0} (not enabled).
7759 Draw subtitles on top of input video using the libass library.
7761 To enable compilation of this filter you need to configure FFmpeg with
7762 @code{--enable-libass}. This filter also requires a build with libavcodec and
7763 libavformat to convert the passed subtitles file to ASS (Advanced Substation
7764 Alpha) subtitles format.
7766 The filter accepts the following options:
7770 Set the filename of the subtitle file to read. It must be specified.
7773 Specify the size of the original video, the video for which the ASS file
7774 was composed. For the syntax of this option, check the "Video size" section in
7775 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
7776 this is necessary to correctly scale the fonts if the aspect ratio has been
7780 Set subtitles input character encoding. @code{subtitles} filter only. Only
7781 useful if not UTF-8.
7783 @item stream_index, si
7784 Set subtitles stream index. @code{subtitles} filter only.
7787 If the first key is not specified, it is assumed that the first value
7788 specifies the @option{filename}.
7790 For example, to render the file @file{sub.srt} on top of the input
7791 video, use the command:
7796 which is equivalent to:
7798 subtitles=filename=sub.srt
7801 To render the default subtitles stream from file @file{video.mkv}, use:
7806 To render the second subtitles stream from that file, use:
7808 subtitles=video.mkv:si=1
7813 Scale the input by 2x and smooth using the Super2xSaI (Scale and
7814 Interpolate) pixel art scaling algorithm.
7816 Useful for enlarging pixel art images without reducing sharpness.
7823 Apply telecine process to the video.
7825 This filter accepts the following options:
7834 The default value is @code{top}.
7838 A string of numbers representing the pulldown pattern you wish to apply.
7839 The default value is @code{23}.
7843 Some typical patterns:
7848 24p: 2332 (preferred)
7855 24p: 222222222223 ("Euro pulldown")
7861 Select the most representative frame in a given sequence of consecutive frames.
7863 The filter accepts the following options:
7867 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
7868 will pick one of them, and then handle the next batch of @var{n} frames until
7869 the end. Default is @code{100}.
7872 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
7873 value will result in a higher memory usage, so a high value is not recommended.
7875 @subsection Examples
7879 Extract one picture each 50 frames:
7885 Complete example of a thumbnail creation with @command{ffmpeg}:
7887 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
7893 Tile several successive frames together.
7895 The filter accepts the following options:
7900 Set the grid size (i.e. the number of lines and columns). For the syntax of
7901 this option, check the "Video size" section in the ffmpeg-utils manual.
7904 Set the maximum number of frames to render in the given area. It must be less
7905 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
7906 the area will be used.
7909 Set the outer border margin in pixels.
7912 Set the inner border thickness (i.e. the number of pixels between frames). For
7913 more advanced padding options (such as having different values for the edges),
7914 refer to the pad video filter.
7917 Specify the color of the unused areaFor the syntax of this option, check the
7918 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
7922 @subsection Examples
7926 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
7928 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
7930 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
7931 duplicating each output frame to accommodate the originally detected frame
7935 Display @code{5} pictures in an area of @code{3x2} frames,
7936 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
7937 mixed flat and named options:
7939 tile=3x2:nb_frames=5:padding=7:margin=2
7945 Perform various types of temporal field interlacing.
7947 Frames are counted starting from 1, so the first input frame is
7950 The filter accepts the following options:
7955 Specify the mode of the interlacing. This option can also be specified
7956 as a value alone. See below for a list of values for this option.
7958 Available values are:
7962 Move odd frames into the upper field, even into the lower field,
7963 generating a double height frame at half frame rate.
7966 Only output even frames, odd frames are dropped, generating a frame with
7967 unchanged height at half frame rate.
7970 Only output odd frames, even frames are dropped, generating a frame with
7971 unchanged height at half frame rate.
7974 Expand each frame to full height, but pad alternate lines with black,
7975 generating a frame with double height at the same input frame rate.
7977 @item interleave_top, 4
7978 Interleave the upper field from odd frames with the lower field from
7979 even frames, generating a frame with unchanged height at half frame rate.
7981 @item interleave_bottom, 5
7982 Interleave the lower field from odd frames with the upper field from
7983 even frames, generating a frame with unchanged height at half frame rate.
7985 @item interlacex2, 6
7986 Double frame rate with unchanged height. Frames are inserted each
7987 containing the second temporal field from the previous input frame and
7988 the first temporal field from the next input frame. This mode relies on
7989 the top_field_first flag. Useful for interlaced video displays with no
7990 field synchronisation.
7993 Numeric values are deprecated but are accepted for backward
7994 compatibility reasons.
7996 Default mode is @code{merge}.
7999 Specify flags influencing the filter process.
8001 Available value for @var{flags} is:
8004 @item low_pass_filter, vlfp
8005 Enable vertical low-pass filtering in the filter.
8006 Vertical low-pass filtering is required when creating an interlaced
8007 destination from a progressive source which contains high-frequency
8008 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8011 Vertical low-pass filtering can only be enabled for @option{mode}
8012 @var{interleave_top} and @var{interleave_bottom}.
8019 Transpose rows with columns in the input video and optionally flip it.
8021 It accepts the following parameters:
8026 Specify the transposition direction.
8028 Can assume the following values:
8030 @item 0, 4, cclock_flip
8031 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8039 Rotate by 90 degrees clockwise, that is:
8047 Rotate by 90 degrees counterclockwise, that is:
8054 @item 3, 7, clock_flip
8055 Rotate by 90 degrees clockwise and vertically flip, that is:
8063 For values between 4-7, the transposition is only done if the input
8064 video geometry is portrait and not landscape. These values are
8065 deprecated, the @code{passthrough} option should be used instead.
8067 Numerical values are deprecated, and should be dropped in favor of
8071 Do not apply the transposition if the input geometry matches the one
8072 specified by the specified value. It accepts the following values:
8075 Always apply transposition.
8077 Preserve portrait geometry (when @var{height} >= @var{width}).
8079 Preserve landscape geometry (when @var{width} >= @var{height}).
8082 Default value is @code{none}.
8085 For example to rotate by 90 degrees clockwise and preserve portrait
8088 transpose=dir=1:passthrough=portrait
8091 The command above can also be specified as:
8093 transpose=1:portrait
8097 Trim the input so that the output contains one continuous subpart of the input.
8099 It accepts the following parameters:
8102 Specify the time of the start of the kept section, i.e. the frame with the
8103 timestamp @var{start} will be the first frame in the output.
8106 Specify the time of the first frame that will be dropped, i.e. the frame
8107 immediately preceding the one with the timestamp @var{end} will be the last
8108 frame in the output.
8111 This is the same as @var{start}, except this option sets the start timestamp
8112 in timebase units instead of seconds.
8115 This is the same as @var{end}, except this option sets the end timestamp
8116 in timebase units instead of seconds.
8119 The maximum duration of the output in seconds.
8122 The number of the first frame that should be passed to the output.
8125 The number of the first frame that should be dropped.
8128 @option{start}, @option{end}, @option{duration} are expressed as time
8129 duration specifications, check the "Time duration" section in the
8130 ffmpeg-utils manual.
8132 Note that the first two sets of the start/end options and the @option{duration}
8133 option look at the frame timestamp, while the _frame variants simply count the
8134 frames that pass through the filter. Also note that this filter does not modify
8135 the timestamps. If you wish for the output timestamps to start at zero, insert a
8136 setpts filter after the trim filter.
8138 If multiple start or end options are set, this filter tries to be greedy and
8139 keep all the frames that match at least one of the specified constraints. To keep
8140 only the part that matches all the constraints at once, chain multiple trim
8143 The defaults are such that all the input is kept. So it is possible to set e.g.
8144 just the end values to keep everything before the specified time.
8149 Drop everything except the second minute of input:
8151 ffmpeg -i INPUT -vf trim=60:120
8155 Keep only the first second:
8157 ffmpeg -i INPUT -vf trim=duration=1
8165 Sharpen or blur the input video.
8167 It accepts the following parameters:
8170 @item luma_msize_x, lx
8171 Set the luma matrix horizontal size. It must be an odd integer between
8172 3 and 63. The default value is 5.
8174 @item luma_msize_y, ly
8175 Set the luma matrix vertical size. It must be an odd integer between 3
8176 and 63. The default value is 5.
8178 @item luma_amount, la
8179 Set the luma effect strength. It must be a floating point number, reasonable
8180 values lay between -1.5 and 1.5.
8182 Negative values will blur the input video, while positive values will
8183 sharpen it, a value of zero will disable the effect.
8185 Default value is 1.0.
8187 @item chroma_msize_x, cx
8188 Set the chroma matrix horizontal size. It must be an odd integer
8189 between 3 and 63. The default value is 5.
8191 @item chroma_msize_y, cy
8192 Set the chroma matrix vertical size. It must be an odd integer
8193 between 3 and 63. The default value is 5.
8195 @item chroma_amount, ca
8196 Set the chroma effect strength. It must be a floating point number, reasonable
8197 values lay between -1.5 and 1.5.
8199 Negative values will blur the input video, while positive values will
8200 sharpen it, a value of zero will disable the effect.
8202 Default value is 0.0.
8205 If set to 1, specify using OpenCL capabilities, only available if
8206 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8210 All parameters are optional and default to the equivalent of the
8211 string '5:5:1.0:5:5:0.0'.
8213 @subsection Examples
8217 Apply strong luma sharpen effect:
8219 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8223 Apply a strong blur of both luma and chroma parameters:
8225 unsharp=7:7:-2:7:7:-2
8229 @anchor{vidstabdetect}
8230 @section vidstabdetect
8232 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8233 @ref{vidstabtransform} for pass 2.
8235 This filter generates a file with relative translation and rotation
8236 transform information about subsequent frames, which is then used by
8237 the @ref{vidstabtransform} filter.
8239 To enable compilation of this filter you need to configure FFmpeg with
8240 @code{--enable-libvidstab}.
8242 This filter accepts the following options:
8246 Set the path to the file used to write the transforms information.
8247 Default value is @file{transforms.trf}.
8250 Set how shaky the video is and how quick the camera is. It accepts an
8251 integer in the range 1-10, a value of 1 means little shakiness, a
8252 value of 10 means strong shakiness. Default value is 5.
8255 Set the accuracy of the detection process. It must be a value in the
8256 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8257 accuracy. Default value is 15.
8260 Set stepsize of the search process. The region around minimum is
8261 scanned with 1 pixel resolution. Default value is 6.
8264 Set minimum contrast. Below this value a local measurement field is
8265 discarded. Must be a floating point value in the range 0-1. Default
8269 Set reference frame number for tripod mode.
8271 If enabled, the motion of the frames is compared to a reference frame
8272 in the filtered stream, identified by the specified number. The idea
8273 is to compensate all movements in a more-or-less static scene and keep
8274 the camera view absolutely still.
8276 If set to 0, it is disabled. The frames are counted starting from 1.
8279 Show fields and transforms in the resulting frames. It accepts an
8280 integer in the range 0-2. Default value is 0, which disables any
8284 @subsection Examples
8294 Analyze strongly shaky movie and put the results in file
8295 @file{mytransforms.trf}:
8297 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8301 Visualize the result of internal transformations in the resulting
8304 vidstabdetect=show=1
8308 Analyze a video with medium shakiness using @command{ffmpeg}:
8310 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8314 @anchor{vidstabtransform}
8315 @section vidstabtransform
8317 Video stabilization/deshaking: pass 2 of 2,
8318 see @ref{vidstabdetect} for pass 1.
8320 Read a file with transform information for each frame and
8321 apply/compensate them. Together with the @ref{vidstabdetect}
8322 filter this can be used to deshake videos. See also
8323 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8324 the unsharp filter, see below.
8326 To enable compilation of this filter you need to configure FFmpeg with
8327 @code{--enable-libvidstab}.
8333 Set path to the file used to read the transforms. Default value is
8334 @file{transforms.trf}).
8337 Set the number of frames (value*2 + 1) used for lowpass filtering the
8338 camera movements. Default value is 10.
8340 For example a number of 10 means that 21 frames are used (10 in the
8341 past and 10 in the future) to smoothen the motion in the video. A
8342 larger values leads to a smoother video, but limits the acceleration
8343 of the camera (pan/tilt movements). 0 is a special case where a
8344 static camera is simulated.
8347 Set the camera path optimization algorithm.
8349 Accepted values are:
8352 gaussian kernel low-pass filter on camera motion (default)
8354 averaging on transformations
8358 Set maximal number of pixels to translate frames. Default value is -1,
8362 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8363 value is -1, meaning no limit.
8366 Specify how to deal with borders that may be visible due to movement
8369 Available values are:
8372 keep image information from previous frame (default)
8374 fill the border black
8378 Invert transforms if set to 1. Default value is 0.
8381 Consider transforms as relative to previsou frame if set to 1,
8382 absolute if set to 0. Default value is 0.
8385 Set percentage to zoom. A positive value will result in a zoom-in
8386 effect, a negative value in a zoom-out effect. Default value is 0 (no
8390 Set optimal zooming to avoid borders.
8392 Accepted values are:
8397 optimal static zoom value is determined (only very strong movements
8398 will lead to visible borders) (default)
8400 optimal adaptive zoom value is determined (no borders will be
8401 visible), see @option{zoomspeed}
8404 Note that the value given at zoom is added to the one calculated here.
8407 Set percent to zoom maximally each frame (enabled when
8408 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8412 Specify type of interpolation.
8414 Available values are:
8419 linear only horizontal
8421 linear in both directions (default)
8423 cubic in both directions (slow)
8427 Enable virtual tripod mode if set to 1, which is equivalent to
8428 @code{relative=0:smoothing=0}. Default value is 0.
8430 Use also @code{tripod} option of @ref{vidstabdetect}.
8433 Increase log verbosity if set to 1. Also the detected global motions
8434 are written to the temporary file @file{global_motions.trf}. Default
8438 @subsection Examples
8442 Use @command{ffmpeg} for a typical stabilization with default values:
8444 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8447 Note the use of the unsharp filter which is always recommended.
8450 Zoom in a bit more and load transform data from a given file:
8452 vidstabtransform=zoom=5:input="mytransforms.trf"
8456 Smoothen the video even more:
8458 vidstabtransform=smoothing=30
8464 Flip the input video vertically.
8466 For example, to vertically flip a video with @command{ffmpeg}:
8468 ffmpeg -i in.avi -vf "vflip" out.avi
8473 Make or reverse a natural vignetting effect.
8475 The filter accepts the following options:
8479 Set lens angle expression as a number of radians.
8481 The value is clipped in the @code{[0,PI/2]} range.
8483 Default value: @code{"PI/5"}
8487 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8491 Set forward/backward mode.
8493 Available modes are:
8496 The larger the distance from the central point, the darker the image becomes.
8499 The larger the distance from the central point, the brighter the image becomes.
8500 This can be used to reverse a vignette effect, though there is no automatic
8501 detection to extract the lens @option{angle} and other settings (yet). It can
8502 also be used to create a burning effect.
8505 Default value is @samp{forward}.
8508 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8510 It accepts the following values:
8513 Evaluate expressions only once during the filter initialization.
8516 Evaluate expressions for each incoming frame. This is way slower than the
8517 @samp{init} mode since it requires all the scalers to be re-computed, but it
8518 allows advanced dynamic expressions.
8521 Default value is @samp{init}.
8524 Set dithering to reduce the circular banding effects. Default is @code{1}
8528 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8529 Setting this value to the SAR of the input will make a rectangular vignetting
8530 following the dimensions of the video.
8532 Default is @code{1/1}.
8535 @subsection Expressions
8537 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8538 following parameters.
8543 input width and height
8546 the number of input frame, starting from 0
8549 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8550 @var{TB} units, NAN if undefined
8553 frame rate of the input video, NAN if the input frame rate is unknown
8556 the PTS (Presentation TimeStamp) of the filtered video frame,
8557 expressed in seconds, NAN if undefined
8560 time base of the input video
8564 @subsection Examples
8568 Apply simple strong vignetting effect:
8574 Make a flickering vignetting:
8576 vignette='PI/4+random(1)*PI/50':eval=frame
8583 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8584 Deinterlacing Filter").
8586 Based on the process described by Martin Weston for BBC R&D, and
8587 implemented based on the de-interlace algorithm written by Jim
8588 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8589 uses filter coefficients calculated by BBC R&D.
8591 There are two sets of filter coefficients, so called "simple":
8592 and "complex". Which set of filter coefficients is used can
8593 be set by passing an optional parameter:
8597 Set the interlacing filter coefficients. Accepts one of the following values:
8601 Simple filter coefficient set.
8603 More-complex filter coefficient set.
8605 Default value is @samp{complex}.
8608 Specify which frames to deinterlace. Accept one of the following values:
8612 Deinterlace all frames,
8614 Only deinterlace frames marked as interlaced.
8617 Default value is @samp{all}.
8623 Deinterlace the input video ("yadif" means "yet another deinterlacing
8626 It accepts the following parameters:
8632 The interlacing mode to adopt. It accepts one of the following values:
8636 Output one frame for each frame.
8638 Output one frame for each field.
8639 @item 2, send_frame_nospatial
8640 Like @code{send_frame}, but it skips the spatial interlacing check.
8641 @item 3, send_field_nospatial
8642 Like @code{send_field}, but it skips the spatial interlacing check.
8645 The default value is @code{send_frame}.
8648 The picture field parity assumed for the input interlaced video. It accepts one
8649 of the following values:
8653 Assume the top field is first.
8655 Assume the bottom field is first.
8657 Enable automatic detection of field parity.
8660 The default value is @code{auto}.
8661 If the interlacing is unknown or the decoder does not export this information,
8662 top field first will be assumed.
8665 Specify which frames to deinterlace. Accept one of the following
8670 Deinterlace all frames.
8672 Only deinterlace frames marked as interlaced.
8675 The default value is @code{all}.
8678 @c man end VIDEO FILTERS
8680 @chapter Video Sources
8681 @c man begin VIDEO SOURCES
8683 Below is a description of the currently available video sources.
8687 Buffer video frames, and make them available to the filter chain.
8689 This source is mainly intended for a programmatic use, in particular
8690 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
8692 It accepts the following parameters:
8697 Specify the size (width and height) of the buffered video frames. For the
8698 syntax of this option, check the "Video size" section in the ffmpeg-utils
8702 The input video width.
8705 The input video height.
8708 A string representing the pixel format of the buffered video frames.
8709 It may be a number corresponding to a pixel format, or a pixel format
8713 Specify the timebase assumed by the timestamps of the buffered frames.
8716 Specify the frame rate expected for the video stream.
8718 @item pixel_aspect, sar
8719 The sample (pixel) aspect ratio of the input video.
8722 Specify the optional parameters to be used for the scale filter which
8723 is automatically inserted when an input change is detected in the
8724 input size or format.
8729 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
8732 will instruct the source to accept video frames with size 320x240 and
8733 with format "yuv410p", assuming 1/24 as the timestamps timebase and
8734 square pixels (1:1 sample aspect ratio).
8735 Since the pixel format with name "yuv410p" corresponds to the number 6
8736 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
8737 this example corresponds to:
8739 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
8742 Alternatively, the options can be specified as a flat string, but this
8743 syntax is deprecated:
8745 @var{width}:@var{height}:@var{pix_fmt}:@var{time_base.num}:@var{time_base.den}:@var{pixel_aspect.num}:@var{pixel_aspect.den}[:@var{sws_param}]
8749 Create a pattern generated by an elementary cellular automaton.
8751 The initial state of the cellular automaton can be defined through the
8752 @option{filename}, and @option{pattern} options. If such options are
8753 not specified an initial state is created randomly.
8755 At each new frame a new row in the video is filled with the result of
8756 the cellular automaton next generation. The behavior when the whole
8757 frame is filled is defined by the @option{scroll} option.
8759 This source accepts the following options:
8763 Read the initial cellular automaton state, i.e. the starting row, from
8765 In the file, each non-whitespace character is considered an alive
8766 cell, a newline will terminate the row, and further characters in the
8767 file will be ignored.
8770 Read the initial cellular automaton state, i.e. the starting row, from
8771 the specified string.
8773 Each non-whitespace character in the string is considered an alive
8774 cell, a newline will terminate the row, and further characters in the
8775 string will be ignored.
8778 Set the video rate, that is the number of frames generated per second.
8781 @item random_fill_ratio, ratio
8782 Set the random fill ratio for the initial cellular automaton row. It
8783 is a floating point number value ranging from 0 to 1, defaults to
8786 This option is ignored when a file or a pattern is specified.
8788 @item random_seed, seed
8789 Set the seed for filling randomly the initial row, must be an integer
8790 included between 0 and UINT32_MAX. If not specified, or if explicitly
8791 set to -1, the filter will try to use a good random seed on a best
8795 Set the cellular automaton rule, it is a number ranging from 0 to 255.
8796 Default value is 110.
8799 Set the size of the output video. For the syntax of this option, check
8800 the "Video size" section in the ffmpeg-utils manual.
8802 If @option{filename} or @option{pattern} is specified, the size is set
8803 by default to the width of the specified initial state row, and the
8804 height is set to @var{width} * PHI.
8806 If @option{size} is set, it must contain the width of the specified
8807 pattern string, and the specified pattern will be centered in the
8810 If a filename or a pattern string is not specified, the size value
8811 defaults to "320x518" (used for a randomly generated initial state).
8814 If set to 1, scroll the output upward when all the rows in the output
8815 have been already filled. If set to 0, the new generated row will be
8816 written over the top row just after the bottom row is filled.
8819 @item start_full, full
8820 If set to 1, completely fill the output with generated rows before
8821 outputting the first frame.
8822 This is the default behavior, for disabling set the value to 0.
8825 If set to 1, stitch the left and right row edges together.
8826 This is the default behavior, for disabling set the value to 0.
8829 @subsection Examples
8833 Read the initial state from @file{pattern}, and specify an output of
8836 cellauto=f=pattern:s=200x400
8840 Generate a random initial row with a width of 200 cells, with a fill
8843 cellauto=ratio=2/3:s=200x200
8847 Create a pattern generated by rule 18 starting by a single alive cell
8848 centered on an initial row with width 100:
8850 cellauto=p=@@:s=100x400:full=0:rule=18
8854 Specify a more elaborated initial pattern:
8856 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
8863 Generate a Mandelbrot set fractal, and progressively zoom towards the
8864 point specified with @var{start_x} and @var{start_y}.
8866 This source accepts the following options:
8871 Set the terminal pts value. Default value is 400.
8874 Set the terminal scale value.
8875 Must be a floating point value. Default value is 0.3.
8878 Set the inner coloring mode, that is the algorithm used to draw the
8879 Mandelbrot fractal internal region.
8881 It shall assume one of the following values:
8886 Show time until convergence.
8888 Set color based on point closest to the origin of the iterations.
8893 Default value is @var{mincol}.
8896 Set the bailout value. Default value is 10.0.
8899 Set the maximum of iterations performed by the rendering
8900 algorithm. Default value is 7189.
8903 Set outer coloring mode.
8904 It shall assume one of following values:
8906 @item iteration_count
8907 Set iteration cound mode.
8908 @item normalized_iteration_count
8909 set normalized iteration count mode.
8911 Default value is @var{normalized_iteration_count}.
8914 Set frame rate, expressed as number of frames per second. Default
8918 Set frame size. For the syntax of this option, check the "Video
8919 size" section in the ffmpeg-utils manual. Default value is "640x480".
8922 Set the initial scale value. Default value is 3.0.
8925 Set the initial x position. Must be a floating point value between
8926 -100 and 100. Default value is -0.743643887037158704752191506114774.
8929 Set the initial y position. Must be a floating point value between
8930 -100 and 100. Default value is -0.131825904205311970493132056385139.
8935 Generate various test patterns, as generated by the MPlayer test filter.
8937 The size of the generated video is fixed, and is 256x256.
8938 This source is useful in particular for testing encoding features.
8940 This source accepts the following options:
8945 Specify the frame rate of the sourced video, as the number of frames
8946 generated per second. It has to be a string in the format
8947 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
8948 number or a valid video frame rate abbreviation. The default value is
8952 Set the video duration of the sourced video. The accepted syntax is:
8957 See also the function @code{av_parse_time()}.
8959 If not specified, or the expressed duration is negative, the video is
8960 supposed to be generated forever.
8964 Set the number or the name of the test to perform. Supported tests are:
8980 Default value is "all", which will cycle through the list of all tests.
8988 will generate a "dc_luma" test pattern.
8992 Provide a frei0r source.
8994 To enable compilation of this filter you need to install the frei0r
8995 header and configure FFmpeg with @code{--enable-frei0r}.
8997 This source accepts the following parameters:
9002 The size of the video to generate. For the syntax of this option, check the
9003 "Video size" section in the ffmpeg-utils manual.
9006 The framerate of the generated video. It may be a string of the form
9007 @var{num}/@var{den} or a frame rate abbreviation.
9010 The name to the frei0r source to load. For more information regarding frei0r and
9011 how to set the parameters, read the @ref{frei0r} section in the video filters
9015 A '|'-separated list of parameters to pass to the frei0r source.
9019 For example, to generate a frei0r partik0l source with size 200x200
9020 and frame rate 10 which is overlayed on the overlay filter main input:
9022 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9027 Generate a life pattern.
9029 This source is based on a generalization of John Conway's life game.
9031 The sourced input represents a life grid, each pixel represents a cell
9032 which can be in one of two possible states, alive or dead. Every cell
9033 interacts with its eight neighbours, which are the cells that are
9034 horizontally, vertically, or diagonally adjacent.
9036 At each interaction the grid evolves according to the adopted rule,
9037 which specifies the number of neighbor alive cells which will make a
9038 cell stay alive or born. The @option{rule} option allows one to specify
9041 This source accepts the following options:
9045 Set the file from which to read the initial grid state. In the file,
9046 each non-whitespace character is considered an alive cell, and newline
9047 is used to delimit the end of each row.
9049 If this option is not specified, the initial grid is generated
9053 Set the video rate, that is the number of frames generated per second.
9056 @item random_fill_ratio, ratio
9057 Set the random fill ratio for the initial random grid. It is a
9058 floating point number value ranging from 0 to 1, defaults to 1/PHI.
9059 It is ignored when a file is specified.
9061 @item random_seed, seed
9062 Set the seed for filling the initial random grid, must be an integer
9063 included between 0 and UINT32_MAX. If not specified, or if explicitly
9064 set to -1, the filter will try to use a good random seed on a best
9070 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
9071 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
9072 @var{NS} specifies the number of alive neighbor cells which make a
9073 live cell stay alive, and @var{NB} the number of alive neighbor cells
9074 which make a dead cell to become alive (i.e. to "born").
9075 "s" and "b" can be used in place of "S" and "B", respectively.
9077 Alternatively a rule can be specified by an 18-bits integer. The 9
9078 high order bits are used to encode the next cell state if it is alive
9079 for each number of neighbor alive cells, the low order bits specify
9080 the rule for "borning" new cells. Higher order bits encode for an
9081 higher number of neighbor cells.
9082 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9083 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9085 Default value is "S23/B3", which is the original Conway's game of life
9086 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9087 cells, and will born a new cell if there are three alive cells around
9091 Set the size of the output video. For the syntax of this option, check the
9092 "Video size" section in the ffmpeg-utils manual.
9094 If @option{filename} is specified, the size is set by default to the
9095 same size of the input file. If @option{size} is set, it must contain
9096 the size specified in the input file, and the initial grid defined in
9097 that file is centered in the larger resulting area.
9099 If a filename is not specified, the size value defaults to "320x240"
9100 (used for a randomly generated initial grid).
9103 If set to 1, stitch the left and right grid edges together, and the
9104 top and bottom edges also. Defaults to 1.
9107 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9108 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9109 value from 0 to 255.
9112 Set the color of living (or new born) cells.
9115 Set the color of dead cells. If @option{mold} is set, this is the first color
9116 used to represent a dead cell.
9119 Set mold color, for definitely dead and moldy cells.
9121 For the syntax of these 3 color options, check the "Color" section in the
9122 ffmpeg-utils manual.
9125 @subsection Examples
9129 Read a grid from @file{pattern}, and center it on a grid of size
9132 life=f=pattern:s=300x300
9136 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9138 life=ratio=2/3:s=200x200
9142 Specify a custom rule for evolving a randomly generated grid:
9148 Full example with slow death effect (mold) using @command{ffplay}:
9150 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9155 @anchor{haldclutsrc}
9159 @anchor{smptehdbars}
9161 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9163 The @code{color} source provides an uniformly colored input.
9165 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9166 @ref{haldclut} filter.
9168 The @code{nullsrc} source returns unprocessed video frames. It is
9169 mainly useful to be employed in analysis / debugging tools, or as the
9170 source for filters which ignore the input data.
9172 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9173 detecting RGB vs BGR issues. You should see a red, green and blue
9174 stripe from top to bottom.
9176 The @code{smptebars} source generates a color bars pattern, based on
9177 the SMPTE Engineering Guideline EG 1-1990.
9179 The @code{smptehdbars} source generates a color bars pattern, based on
9180 the SMPTE RP 219-2002.
9182 The @code{testsrc} source generates a test video pattern, showing a
9183 color pattern, a scrolling gradient and a timestamp. This is mainly
9184 intended for testing purposes.
9186 The sources accept the following parameters:
9191 Specify the color of the source, only available in the @code{color}
9192 source. For the syntax of this option, check the "Color" section in the
9193 ffmpeg-utils manual.
9196 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9197 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9198 pixels to be used as identity matrix for 3D lookup tables. Each component is
9199 coded on a @code{1/(N*N)} scale.
9202 Specify the size of the sourced video. For the syntax of this option, check the
9203 "Video size" section in the ffmpeg-utils manual. The default value is
9206 This option is not available with the @code{haldclutsrc} filter.
9209 Specify the frame rate of the sourced video, as the number of frames
9210 generated per second. It has to be a string in the format
9211 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9212 number or a valid video frame rate abbreviation. The default value is
9216 Set the sample aspect ratio of the sourced video.
9219 Set the video duration of the sourced video. The accepted syntax is:
9221 [-]HH[:MM[:SS[.m...]]]
9224 Also see the the @code{av_parse_time()} function.
9226 If not specified, or the expressed duration is negative, the video is
9227 supposed to be generated forever.
9230 Set the number of decimals to show in the timestamp, only available in the
9231 @code{testsrc} source.
9233 The displayed timestamp value will correspond to the original
9234 timestamp value multiplied by the power of 10 of the specified
9235 value. Default value is 0.
9238 For example the following:
9240 testsrc=duration=5.3:size=qcif:rate=10
9243 will generate a video with a duration of 5.3 seconds, with size
9244 176x144 and a frame rate of 10 frames per second.
9246 The following graph description will generate a red source
9247 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9250 color=c=red@@0.2:s=qcif:r=10
9253 If the input content is to be ignored, @code{nullsrc} can be used. The
9254 following command generates noise in the luminance plane by employing
9255 the @code{geq} filter:
9257 nullsrc=s=256x256, geq=random(1)*255:128:128
9260 @subsection Commands
9262 The @code{color} source supports the following commands:
9266 Set the color of the created image. Accepts the same syntax of the
9267 corresponding @option{color} option.
9270 @c man end VIDEO SOURCES
9272 @chapter Video Sinks
9273 @c man begin VIDEO SINKS
9275 Below is a description of the currently available video sinks.
9279 Buffer video frames, and make them available to the end of the filter
9282 This sink is mainly intended for programmatic use, in particular
9283 through the interface defined in @file{libavfilter/buffersink.h}
9284 or the options system.
9286 It accepts a pointer to an AVBufferSinkContext structure, which
9287 defines the incoming buffers' formats, to be passed as the opaque
9288 parameter to @code{avfilter_init_filter} for initialization.
9292 Null video sink: do absolutely nothing with the input video. It is
9293 mainly useful as a template and for use in analysis / debugging
9296 @c man end VIDEO SINKS
9298 @chapter Multimedia Filters
9299 @c man begin MULTIMEDIA FILTERS
9301 Below is a description of the currently available multimedia filters.
9303 @section avectorscope
9305 Convert input audio to a video output, representing the audio vector
9308 The filter is used to measure the difference between channels of stereo
9309 audio stream. A monoaural signal, consisting of identical left and right
9310 signal, results in straight vertical line. Any stereo separation is visible
9311 as a deviation from this line, creating a Lissajous figure.
9312 If the straight (or deviation from it) but horizontal line appears this
9313 indicates that the left and right channels are out of phase.
9315 The filter accepts the following options:
9319 Set the vectorscope mode.
9321 Available values are:
9324 Lissajous rotated by 45 degrees.
9327 Same as above but not rotated.
9330 Default value is @samp{lissajous}.
9333 Set the video size for the output. For the syntax of this option, check the "Video size"
9334 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9337 Set the output frame rate. Default value is @code{25}.
9342 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9343 Allowed range is @code{[0, 255]}.
9348 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9349 Allowed range is @code{[0, 255]}.
9352 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9355 @subsection Examples
9359 Complete example using @command{ffplay}:
9361 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9362 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9368 Concatenate audio and video streams, joining them together one after the
9371 The filter works on segments of synchronized video and audio streams. All
9372 segments must have the same number of streams of each type, and that will
9373 also be the number of streams at output.
9375 The filter accepts the following options:
9380 Set the number of segments. Default is 2.
9383 Set the number of output video streams, that is also the number of video
9384 streams in each segment. Default is 1.
9387 Set the number of output audio streams, that is also the number of audio
9388 streams in each segment. Default is 0.
9391 Activate unsafe mode: do not fail if segments have a different format.
9395 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9396 @var{a} audio outputs.
9398 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9399 segment, in the same order as the outputs, then the inputs for the second
9402 Related streams do not always have exactly the same duration, for various
9403 reasons including codec frame size or sloppy authoring. For that reason,
9404 related synchronized streams (e.g. a video and its audio track) should be
9405 concatenated at once. The concat filter will use the duration of the longest
9406 stream in each segment (except the last one), and if necessary pad shorter
9407 audio streams with silence.
9409 For this filter to work correctly, all segments must start at timestamp 0.
9411 All corresponding streams must have the same parameters in all segments; the
9412 filtering system will automatically select a common pixel format for video
9413 streams, and a common sample format, sample rate and channel layout for
9414 audio streams, but other settings, such as resolution, must be converted
9415 explicitly by the user.
9417 Different frame rates are acceptable but will result in variable frame rate
9418 at output; be sure to configure the output file to handle it.
9420 @subsection Examples
9424 Concatenate an opening, an episode and an ending, all in bilingual version
9425 (video in stream 0, audio in streams 1 and 2):
9427 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9428 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9429 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9430 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9434 Concatenate two parts, handling audio and video separately, using the
9435 (a)movie sources, and adjusting the resolution:
9437 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9438 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9439 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9441 Note that a desync will happen at the stitch if the audio and video streams
9442 do not have exactly the same duration in the first file.
9448 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9449 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9450 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9451 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9453 The filter also has a video output (see the @var{video} option) with a real
9454 time graph to observe the loudness evolution. The graphic contains the logged
9455 message mentioned above, so it is not printed anymore when this option is set,
9456 unless the verbose logging is set. The main graphing area contains the
9457 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9458 the momentary loudness (400 milliseconds).
9460 More information about the Loudness Recommendation EBU R128 on
9461 @url{http://tech.ebu.ch/loudness}.
9463 The filter accepts the following options:
9468 Activate the video output. The audio stream is passed unchanged whether this
9469 option is set or no. The video stream will be the first output stream if
9470 activated. Default is @code{0}.
9473 Set the video size. This option is for video only. For the syntax of this
9474 option, check the "Video size" section in the ffmpeg-utils manual. Default
9475 and minimum resolution is @code{640x480}.
9478 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9479 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9480 other integer value between this range is allowed.
9483 Set metadata injection. If set to @code{1}, the audio input will be segmented
9484 into 100ms output frames, each of them containing various loudness information
9485 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9487 Default is @code{0}.
9490 Force the frame logging level.
9492 Available values are:
9495 information logging level
9497 verbose logging level
9500 By default, the logging level is set to @var{info}. If the @option{video} or
9501 the @option{metadata} options are set, it switches to @var{verbose}.
9506 Available modes can be cumulated (the option is a @code{flag} type). Possible
9510 Disable any peak mode (default).
9512 Enable sample-peak mode.
9514 Simple peak mode looking for the higher sample value. It logs a message
9515 for sample-peak (identified by @code{SPK}).
9517 Enable true-peak mode.
9519 If enabled, the peak lookup is done on an over-sampled version of the input
9520 stream for better peak accuracy. It logs a message for true-peak.
9521 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9522 This mode requires a build with @code{libswresample}.
9527 @subsection Examples
9531 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9533 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9537 Run an analysis with @command{ffmpeg}:
9539 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9543 @section interleave, ainterleave
9545 Temporally interleave frames from several inputs.
9547 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9549 These filters read frames from several inputs and send the oldest
9550 queued frame to the output.
9552 Input streams must have a well defined, monotonically increasing frame
9555 In order to submit one frame to output, these filters need to enqueue
9556 at least one frame for each input, so they cannot work in case one
9557 input is not yet terminated and will not receive incoming frames.
9559 For example consider the case when one input is a @code{select} filter
9560 which always drop input frames. The @code{interleave} filter will keep
9561 reading from that input, but it will never be able to send new frames
9562 to output until the input will send an end-of-stream signal.
9564 Also, depending on inputs synchronization, the filters will drop
9565 frames in case one input receives more frames than the other ones, and
9566 the queue is already filled.
9568 These filters accept the following options:
9572 Set the number of different inputs, it is 2 by default.
9575 @subsection Examples
9579 Interleave frames belonging to different streams using @command{ffmpeg}:
9581 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9585 Add flickering blur effect:
9587 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9591 @section perms, aperms
9593 Set read/write permissions for the output frames.
9595 These filters are mainly aimed at developers to test direct path in the
9596 following filter in the filtergraph.
9598 The filters accept the following options:
9602 Select the permissions mode.
9604 It accepts the following values:
9607 Do nothing. This is the default.
9609 Set all the output frames read-only.
9611 Set all the output frames directly writable.
9613 Make the frame read-only if writable, and writable if read-only.
9615 Set each output frame read-only or writable randomly.
9619 Set the seed for the @var{random} mode, must be an integer included between
9620 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9621 @code{-1}, the filter will try to use a good random seed on a best effort
9625 Note: in case of auto-inserted filter between the permission filter and the
9626 following one, the permission might not be received as expected in that
9627 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9628 perms/aperms filter can avoid this problem.
9630 @section select, aselect
9632 Select frames to pass in output.
9634 This filter accepts the following options:
9639 Set expression, which is evaluated for each input frame.
9641 If the expression is evaluated to zero, the frame is discarded.
9643 If the evaluation result is negative or NaN, the frame is sent to the
9644 first output; otherwise it is sent to the output with index
9645 @code{ceil(val)-1}, assuming that the input index starts from 0.
9647 For example a value of @code{1.2} corresponds to the output with index
9648 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
9651 Set the number of outputs. The output to which to send the selected
9652 frame is based on the result of the evaluation. Default value is 1.
9655 The expression can contain the following constants:
9659 The (sequential) number of the filtered frame, starting from 0.
9662 The (sequential) number of the selected frame, starting from 0.
9664 @item prev_selected_n
9665 The sequential number of the last selected frame. It's NAN if undefined.
9668 The timebase of the input timestamps.
9671 The PTS (Presentation TimeStamp) of the filtered video frame,
9672 expressed in @var{TB} units. It's NAN if undefined.
9675 The PTS of the filtered video frame,
9676 expressed in seconds. It's NAN if undefined.
9679 The PTS of the previously filtered video frame. It's NAN if undefined.
9681 @item prev_selected_pts
9682 The PTS of the last previously filtered video frame. It's NAN if undefined.
9684 @item prev_selected_t
9685 The PTS of the last previously selected video frame. It's NAN if undefined.
9688 The PTS of the first video frame in the video. It's NAN if undefined.
9691 The time of the first video frame in the video. It's NAN if undefined.
9693 @item pict_type @emph{(video only)}
9694 The type of the filtered frame. It can assume one of the following
9706 @item interlace_type @emph{(video only)}
9707 The frame interlace type. It can assume one of the following values:
9710 The frame is progressive (not interlaced).
9712 The frame is top-field-first.
9714 The frame is bottom-field-first.
9717 @item consumed_sample_n @emph{(audio only)}
9718 the number of selected samples before the current frame
9720 @item samples_n @emph{(audio only)}
9721 the number of samples in the current frame
9723 @item sample_rate @emph{(audio only)}
9724 the input sample rate
9727 This is 1 if the filtered frame is a key-frame, 0 otherwise.
9730 the position in the file of the filtered frame, -1 if the information
9731 is not available (e.g. for synthetic video)
9733 @item scene @emph{(video only)}
9734 value between 0 and 1 to indicate a new scene; a low value reflects a low
9735 probability for the current frame to introduce a new scene, while a higher
9736 value means the current frame is more likely to be one (see the example below)
9740 The default value of the select expression is "1".
9742 @subsection Examples
9746 Select all frames in input:
9751 The example above is the same as:
9763 Select only I-frames:
9765 select='eq(pict_type\,I)'
9769 Select one frame every 100:
9771 select='not(mod(n\,100))'
9775 Select only frames contained in the 10-20 time interval:
9777 select=between(t\,10\,20)
9781 Select only I frames contained in the 10-20 time interval:
9783 select=between(t\,10\,20)*eq(pict_type\,I)
9787 Select frames with a minimum distance of 10 seconds:
9789 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
9793 Use aselect to select only audio frames with samples number > 100:
9795 aselect='gt(samples_n\,100)'
9799 Create a mosaic of the first scenes:
9801 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
9804 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
9808 Send even and odd frames to separate outputs, and compose them:
9810 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
9814 @section sendcmd, asendcmd
9816 Send commands to filters in the filtergraph.
9818 These filters read commands to be sent to other filters in the
9821 @code{sendcmd} must be inserted between two video filters,
9822 @code{asendcmd} must be inserted between two audio filters, but apart
9823 from that they act the same way.
9825 The specification of commands can be provided in the filter arguments
9826 with the @var{commands} option, or in a file specified by the
9827 @var{filename} option.
9829 These filters accept the following options:
9832 Set the commands to be read and sent to the other filters.
9834 Set the filename of the commands to be read and sent to the other
9838 @subsection Commands syntax
9840 A commands description consists of a sequence of interval
9841 specifications, comprising a list of commands to be executed when a
9842 particular event related to that interval occurs. The occurring event
9843 is typically the current frame time entering or leaving a given time
9846 An interval is specified by the following syntax:
9848 @var{START}[-@var{END}] @var{COMMANDS};
9851 The time interval is specified by the @var{START} and @var{END} times.
9852 @var{END} is optional and defaults to the maximum time.
9854 The current frame time is considered within the specified interval if
9855 it is included in the interval [@var{START}, @var{END}), that is when
9856 the time is greater or equal to @var{START} and is lesser than
9859 @var{COMMANDS} consists of a sequence of one or more command
9860 specifications, separated by ",", relating to that interval. The
9861 syntax of a command specification is given by:
9863 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
9866 @var{FLAGS} is optional and specifies the type of events relating to
9867 the time interval which enable sending the specified command, and must
9868 be a non-null sequence of identifier flags separated by "+" or "|" and
9869 enclosed between "[" and "]".
9871 The following flags are recognized:
9874 The command is sent when the current frame timestamp enters the
9875 specified interval. In other words, the command is sent when the
9876 previous frame timestamp was not in the given interval, and the
9880 The command is sent when the current frame timestamp leaves the
9881 specified interval. In other words, the command is sent when the
9882 previous frame timestamp was in the given interval, and the
9886 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
9889 @var{TARGET} specifies the target of the command, usually the name of
9890 the filter class or a specific filter instance name.
9892 @var{COMMAND} specifies the name of the command for the target filter.
9894 @var{ARG} is optional and specifies the optional list of argument for
9895 the given @var{COMMAND}.
9897 Between one interval specification and another, whitespaces, or
9898 sequences of characters starting with @code{#} until the end of line,
9899 are ignored and can be used to annotate comments.
9901 A simplified BNF description of the commands specification syntax
9904 @var{COMMAND_FLAG} ::= "enter" | "leave"
9905 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
9906 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
9907 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
9908 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
9909 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
9912 @subsection Examples
9916 Specify audio tempo change at second 4:
9918 asendcmd=c='4.0 atempo tempo 1.5',atempo
9922 Specify a list of drawtext and hue commands in a file.
9924 # show text in the interval 5-10
9925 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
9926 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
9928 # desaturate the image in the interval 15-20
9929 15.0-20.0 [enter] hue s 0,
9930 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
9932 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
9934 # apply an exponential saturation fade-out effect, starting from time 25
9935 25 [enter] hue s exp(25-t)
9938 A filtergraph allowing to read and process the above command list
9939 stored in a file @file{test.cmd}, can be specified with:
9941 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
9946 @section setpts, asetpts
9948 Change the PTS (presentation timestamp) of the input frames.
9950 @code{setpts} works on video frames, @code{asetpts} on audio frames.
9952 This filter accepts the following options:
9957 The expression which is evaluated for each frame to construct its timestamp.
9961 The expression is evaluated through the eval API and can contain the following
9966 frame rate, only defined for constant frame-rate video
9969 The presentation timestamp in input
9972 The count of the input frame for video or the number of consumed samples,
9973 not including the current frame for audio, starting from 0.
9975 @item NB_CONSUMED_SAMPLES
9976 The number of consumed samples, not including the current frame (only
9980 The number of samples in the current frame (only audio)
9982 @item SAMPLE_RATE, SR
9983 The audio sample rate.
9986 The PTS of the first frame.
9989 the time in seconds of the first frame
9992 State whether the current frame is interlaced.
9995 the time in seconds of the current frame
9998 original position in the file of the frame, or undefined if undefined
9999 for the current frame
10002 The previous input PTS.
10005 previous input time in seconds
10008 The previous output PTS.
10011 previous output time in seconds
10014 The wallclock (RTC) time in microseconds.. This is deprecated, use time(0)
10018 The wallclock (RTC) time at the start of the movie in microseconds.
10021 The timebase of the input timestamps.
10025 @subsection Examples
10029 Start counting PTS from zero
10031 setpts=PTS-STARTPTS
10035 Apply fast motion effect:
10041 Apply slow motion effect:
10047 Set fixed rate of 25 frames per second:
10053 Set fixed rate 25 fps with some jitter:
10055 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
10059 Apply an offset of 10 seconds to the input PTS:
10065 Generate timestamps from a "live source" and rebase onto the current timebase:
10067 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
10071 Generate timestamps by counting samples:
10078 @section settb, asettb
10080 Set the timebase to use for the output frames timestamps.
10081 It is mainly useful for testing timebase configuration.
10083 It accepts the following parameters:
10088 The expression which is evaluated into the output timebase.
10092 The value for @option{tb} is an arithmetic expression representing a
10093 rational. The expression can contain the constants "AVTB" (the default
10094 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10095 audio only). Default value is "intb".
10097 @subsection Examples
10101 Set the timebase to 1/25:
10107 Set the timebase to 1/10:
10113 Set the timebase to 1001/1000:
10119 Set the timebase to 2*intb:
10125 Set the default timebase value:
10131 @section showspectrum
10133 Convert input audio to a video output, representing the audio frequency
10136 The filter accepts the following options:
10140 Specify the video size for the output. For the syntax of this option, check
10141 the "Video size" section in the ffmpeg-utils manual. Default value is
10145 Specify if the spectrum should slide along the window. Default value is
10149 Specify display mode.
10151 It accepts the following values:
10154 all channels are displayed in the same row
10156 all channels are displayed in separate rows
10159 Default value is @samp{combined}.
10162 Specify display color mode.
10164 It accepts the following values:
10167 each channel is displayed in a separate color
10169 each channel is is displayed using the same color scheme
10172 Default value is @samp{channel}.
10175 Specify scale used for calculating intensity color values.
10177 It accepts the following values:
10182 square root, default
10189 Default value is @samp{sqrt}.
10192 Set saturation modifier for displayed colors. Negative values provide
10193 alternative color scheme. @code{0} is no saturation at all.
10194 Saturation must be in [-10.0, 10.0] range.
10195 Default value is @code{1}.
10198 Set window function.
10200 It accepts the following values:
10203 No samples pre-processing (do not expect this to be faster)
10212 Default value is @code{hann}.
10215 The usage is very similar to the showwaves filter; see the examples in that
10218 @subsection Examples
10222 Large window with logarithmic color scaling:
10224 showspectrum=s=1280x480:scale=log
10228 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10230 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10231 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10237 Convert input audio to a video output, representing the samples waves.
10239 The filter accepts the following options:
10243 Specify the video size for the output. For the syntax of this option, check
10244 the "Video size" section in the ffmpeg-utils manual. Default value
10250 Available values are:
10253 Draw a point for each sample.
10256 Draw a vertical line for each sample.
10259 Default value is @code{point}.
10262 Set the number of samples which are printed on the same column. A
10263 larger value will decrease the frame rate. Must be a positive
10264 integer. This option can be set only if the value for @var{rate}
10265 is not explicitly specified.
10268 Set the (approximate) output frame rate. This is done by setting the
10269 option @var{n}. Default value is "25".
10273 @subsection Examples
10277 Output the input file audio and the corresponding video representation
10280 amovie=a.mp3,asplit[out0],showwaves[out1]
10284 Create a synthetic signal and show it with showwaves, forcing a
10285 frame rate of 30 frames per second:
10287 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10291 @section split, asplit
10293 Split input into several identical outputs.
10295 @code{asplit} works with audio input, @code{split} with video.
10297 The filter accepts a single parameter which specifies the number of outputs. If
10298 unspecified, it defaults to 2.
10300 @subsection Examples
10304 Create two separate outputs from the same input:
10306 [in] split [out0][out1]
10310 To create 3 or more outputs, you need to specify the number of
10313 [in] asplit=3 [out0][out1][out2]
10317 Create two separate outputs from the same input, one cropped and
10320 [in] split [splitout1][splitout2];
10321 [splitout1] crop=100:100:0:0 [cropout];
10322 [splitout2] pad=200:200:100:100 [padout];
10326 Create 5 copies of the input audio with @command{ffmpeg}:
10328 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10334 Receive commands sent through a libzmq client, and forward them to
10335 filters in the filtergraph.
10337 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10338 must be inserted between two video filters, @code{azmq} between two
10341 To enable these filters you need to install the libzmq library and
10342 headers and configure FFmpeg with @code{--enable-libzmq}.
10344 For more information about libzmq see:
10345 @url{http://www.zeromq.org/}
10347 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10348 receives messages sent through a network interface defined by the
10349 @option{bind_address} option.
10351 The received message must be in the form:
10353 @var{TARGET} @var{COMMAND} [@var{ARG}]
10356 @var{TARGET} specifies the target of the command, usually the name of
10357 the filter class or a specific filter instance name.
10359 @var{COMMAND} specifies the name of the command for the target filter.
10361 @var{ARG} is optional and specifies the optional argument list for the
10362 given @var{COMMAND}.
10364 Upon reception, the message is processed and the corresponding command
10365 is injected into the filtergraph. Depending on the result, the filter
10366 will send a reply to the client, adopting the format:
10368 @var{ERROR_CODE} @var{ERROR_REASON}
10372 @var{MESSAGE} is optional.
10374 @subsection Examples
10376 Look at @file{tools/zmqsend} for an example of a zmq client which can
10377 be used to send commands processed by these filters.
10379 Consider the following filtergraph generated by @command{ffplay}
10381 ffplay -dumpgraph 1 -f lavfi "
10382 color=s=100x100:c=red [l];
10383 color=s=100x100:c=blue [r];
10384 nullsrc=s=200x100, zmq [bg];
10385 [bg][l] overlay [bg+l];
10386 [bg+l][r] overlay=x=100 "
10389 To change the color of the left side of the video, the following
10390 command can be used:
10392 echo Parsed_color_0 c yellow | tools/zmqsend
10395 To change the right side:
10397 echo Parsed_color_1 c pink | tools/zmqsend
10400 @c man end MULTIMEDIA FILTERS
10402 @chapter Multimedia Sources
10403 @c man begin MULTIMEDIA SOURCES
10405 Below is a description of the currently available multimedia sources.
10409 This is the same as @ref{movie} source, except it selects an audio
10415 Read audio and/or video stream(s) from a movie container.
10417 It accepts the following parameters:
10421 The name of the resource to read (not necessarily a file; it can also be a
10422 device or a stream accessed through some protocol).
10424 @item format_name, f
10425 Specifies the format assumed for the movie to read, and can be either
10426 the name of a container or an input device. If not specified, the
10427 format is guessed from @var{movie_name} or by probing.
10429 @item seek_point, sp
10430 Specifies the seek point in seconds. The frames will be output
10431 starting from this seek point. The parameter is evaluated with
10432 @code{av_strtod}, so the numerical value may be suffixed by an IS
10433 postfix. The default value is "0".
10436 Specifies the streams to read. Several streams can be specified,
10437 separated by "+". The source will then have as many outputs, in the
10438 same order. The syntax is explained in the ``Stream specifiers''
10439 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10440 respectively the default (best suited) video and audio stream. Default
10441 is "dv", or "da" if the filter is called as "amovie".
10443 @item stream_index, si
10444 Specifies the index of the video stream to read. If the value is -1,
10445 the most suitable video stream will be automatically selected. The default
10446 value is "-1". Deprecated. If the filter is called "amovie", it will select
10447 audio instead of video.
10450 Specifies how many times to read the stream in sequence.
10451 If the value is less than 1, the stream will be read again and again.
10452 Default value is "1".
10454 Note that when the movie is looped the source timestamps are not
10455 changed, so it will generate non monotonically increasing timestamps.
10458 It allows overlaying a second video on top of the main input of
10459 a filtergraph, as shown in this graph:
10461 input -----------> deltapts0 --> overlay --> output
10464 movie --> scale--> deltapts1 -------+
10466 @subsection Examples
10470 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
10471 on top of the input labelled "in":
10473 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10474 [in] setpts=PTS-STARTPTS [main];
10475 [main][over] overlay=16:16 [out]
10479 Read from a video4linux2 device, and overlay it on top of the input
10482 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10483 [in] setpts=PTS-STARTPTS [main];
10484 [main][over] overlay=16:16 [out]
10488 Read the first video stream and the audio stream with id 0x81 from
10489 dvd.vob; the video is connected to the pad named "video" and the audio is
10490 connected to the pad named "audio":
10492 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10496 @c man end MULTIMEDIA SOURCES