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 recognized by the
118 @option{-filter}/@option{-vf}/@option{-af} and
119 @option{-filter_complex} options in @command{ffmpeg} and
120 @option{-vf}/@option{-af} in @command{ffplay}, and by the
121 @code{avfilter_graph_parse_ptr()} function defined in
122 @file{libavfilter/avfilter.h}.
124 A filterchain consists of a sequence of connected filters, each one
125 connected to the previous one in the sequence. A filterchain is
126 represented by a list of ","-separated filter descriptions.
128 A filtergraph consists of a sequence of filterchains. A sequence of
129 filterchains is represented by a list of ";"-separated filterchain
132 A filter is represented by a string of the form:
133 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
135 @var{filter_name} is the name of the filter class of which the
136 described filter is an instance of, and has to be the name of one of
137 the filter classes registered in the program.
138 The name of the filter class is optionally followed by a string
141 @var{arguments} is a string which contains the parameters used to
142 initialize the filter instance. It may have one of two forms:
146 A ':'-separated list of @var{key=value} pairs.
149 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
150 the option names in the order they are declared. E.g. the @code{fade} filter
151 declares three options in this order -- @option{type}, @option{start_frame} and
152 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
153 @var{in} is assigned to the option @option{type}, @var{0} to
154 @option{start_frame} and @var{30} to @option{nb_frames}.
157 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
158 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
159 follow the same constraints order of the previous point. The following
160 @var{key=value} pairs can be set in any preferred order.
164 If the option value itself is a list of items (e.g. the @code{format} filter
165 takes a list of pixel formats), the items in the list are usually separated by
168 The list of arguments can be quoted using the character @samp{'} as initial
169 and ending mark, and the character @samp{\} for escaping the characters
170 within the quoted text; otherwise the argument string is considered
171 terminated when the next special character (belonging to the set
172 @samp{[]=;,}) is encountered.
174 The name and arguments of the filter are optionally preceded and
175 followed by a list of link labels.
176 A link label allows one to name a link and associate it to a filter output
177 or input pad. The preceding labels @var{in_link_1}
178 ... @var{in_link_N}, are associated to the filter input pads,
179 the following labels @var{out_link_1} ... @var{out_link_M}, are
180 associated to the output pads.
182 When two link labels with the same name are found in the
183 filtergraph, a link between the corresponding input and output pad is
186 If an output pad is not labelled, it is linked by default to the first
187 unlabelled input pad of the next filter in the filterchain.
188 For example in the filterchain
190 nullsrc, split[L1], [L2]overlay, nullsink
192 the split filter instance has two output pads, and the overlay filter
193 instance two input pads. The first output pad of split is labelled
194 "L1", the first input pad of overlay is labelled "L2", and the second
195 output pad of split is linked to the second input pad of overlay,
196 which are both unlabelled.
198 In a filter description, if the input label of the first filter is not
199 specified, "in" is assumed; if the output label of the last filter is not
200 specified, "out" is assumed.
202 In a complete filterchain all the unlabelled filter input and output
203 pads must be connected. A filtergraph is considered valid if all the
204 filter input and output pads of all the filterchains are connected.
206 Libavfilter will automatically insert @ref{scale} filters where format
207 conversion is required. It is possible to specify swscale flags
208 for those automatically inserted scalers by prepending
209 @code{sws_flags=@var{flags};}
210 to the filtergraph description.
212 Here is a BNF description of the filtergraph syntax:
214 @var{NAME} ::= sequence of alphanumeric characters and '_'
215 @var{LINKLABEL} ::= "[" @var{NAME} "]"
216 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
217 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
218 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
219 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
220 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
223 @section Notes on filtergraph escaping
225 Filtergraph description composition entails several levels of
226 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
227 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
228 information about the employed escaping procedure.
230 A first level escaping affects the content of each filter option
231 value, which may contain the special character @code{:} used to
232 separate values, or one of the escaping characters @code{\'}.
234 A second level escaping affects the whole filter description, which
235 may contain the escaping characters @code{\'} or the special
236 characters @code{[],;} used by the filtergraph description.
238 Finally, when you specify a filtergraph on a shell commandline, you
239 need to perform a third level escaping for the shell special
240 characters contained within it.
242 For example, consider the following string to be embedded in
243 the @ref{drawtext} filter description @option{text} value:
245 this is a 'string': may contain one, or more, special characters
248 This string contains the @code{'} special escaping character, and the
249 @code{:} special character, so it needs to be escaped in this way:
251 text=this is a \'string\'\: may contain one, or more, special characters
254 A second level of escaping is required when embedding the filter
255 description in a filtergraph description, in order to escape all the
256 filtergraph special characters. Thus the example above becomes:
258 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
260 (note that in addition to the @code{\'} escaping special characters,
261 also @code{,} needs to be escaped).
263 Finally an additional level of escaping is needed when writing the
264 filtergraph description in a shell command, which depends on the
265 escaping rules of the adopted shell. For example, assuming that
266 @code{\} is special and needs to be escaped with another @code{\}, the
267 previous string will finally result in:
269 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
272 @chapter Timeline editing
274 Some filters support a generic @option{enable} option. For the filters
275 supporting timeline editing, this option can be set to an expression which is
276 evaluated before sending a frame to the filter. If the evaluation is non-zero,
277 the filter will be enabled, otherwise the frame will be sent unchanged to the
278 next filter in the filtergraph.
280 The expression accepts the following values:
283 timestamp expressed in seconds, NAN if the input timestamp is unknown
286 sequential number of the input frame, starting from 0
289 the position in the file of the input frame, NAN if unknown
293 width and height of the input frame if video
296 Additionally, these filters support an @option{enable} command that can be used
297 to re-define the expression.
299 Like any other filtering option, the @option{enable} option follows the same
302 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
303 minutes, and a @ref{curves} filter starting at 3 seconds:
305 smartblur = enable='between(t,10,3*60)',
306 curves = enable='gte(t,3)' : preset=cross_process
309 @c man end FILTERGRAPH DESCRIPTION
311 @chapter Audio Filters
312 @c man begin AUDIO FILTERS
314 When you configure your FFmpeg build, you can disable any of the
315 existing filters using @code{--disable-filters}.
316 The configure output will show the audio filters included in your
319 Below is a description of the currently available audio filters.
323 Apply cross fade from one input audio stream to another input audio stream.
324 The cross fade is applied for specified duration near the end of first stream.
326 The filter accepts the following options:
330 Specify the number of samples for which the cross fade effect has to last.
331 At the end of the cross fade effect the first input audio will be completely
332 silent. Default is 44100.
335 Specify the duration of the cross fade effect. See
336 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
337 for the accepted syntax.
338 By default the duration is determined by @var{nb_samples}.
339 If set this option is used instead of @var{nb_samples}.
342 Should first stream end overlap with second stream start. Default is enabled.
345 Set curve for cross fade transition for first stream.
348 Set curve for cross fade transition for second stream.
350 For description of available curve types see @ref{afade} filter description.
357 Cross fade from one input to another:
359 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac
363 Cross fade from one input to another but without overlapping:
365 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac
371 Delay one or more audio channels.
373 Samples in delayed channel are filled with silence.
375 The filter accepts the following option:
379 Set list of delays in milliseconds for each channel separated by '|'.
380 At least one delay greater than 0 should be provided.
381 Unused delays will be silently ignored. If number of given delays is
382 smaller than number of channels all remaining channels will not be delayed.
389 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
390 the second channel (and any other channels that may be present) unchanged.
398 Apply echoing to the input audio.
400 Echoes are reflected sound and can occur naturally amongst mountains
401 (and sometimes large buildings) when talking or shouting; digital echo
402 effects emulate this behaviour and are often used to help fill out the
403 sound of a single instrument or vocal. The time difference between the
404 original signal and the reflection is the @code{delay}, and the
405 loudness of the reflected signal is the @code{decay}.
406 Multiple echoes can have different delays and decays.
408 A description of the accepted parameters follows.
412 Set input gain of reflected signal. Default is @code{0.6}.
415 Set output gain of reflected signal. Default is @code{0.3}.
418 Set list of time intervals in milliseconds between original signal and reflections
419 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
420 Default is @code{1000}.
423 Set list of loudnesses of reflected signals separated by '|'.
424 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
425 Default is @code{0.5}.
432 Make it sound as if there are twice as many instruments as are actually playing:
434 aecho=0.8:0.88:60:0.4
438 If delay is very short, then it sound like a (metallic) robot playing music:
444 A longer delay will sound like an open air concert in the mountains:
446 aecho=0.8:0.9:1000:0.3
450 Same as above but with one more mountain:
452 aecho=0.8:0.9:1000|1800:0.3|0.25
458 Modify an audio signal according to the specified expressions.
460 This filter accepts one or more expressions (one for each channel),
461 which are evaluated and used to modify a corresponding audio signal.
463 It accepts the following parameters:
467 Set the '|'-separated expressions list for each separate channel. If
468 the number of input channels is greater than the number of
469 expressions, the last specified expression is used for the remaining
472 @item channel_layout, c
473 Set output channel layout. If not specified, the channel layout is
474 specified by the number of expressions. If set to @samp{same}, it will
475 use by default the same input channel layout.
478 Each expression in @var{exprs} can contain the following constants and functions:
482 channel number of the current expression
485 number of the evaluated sample, starting from 0
491 time of the evaluated sample expressed in seconds
494 @item nb_out_channels
495 input and output number of channels
498 the value of input channel with number @var{CH}
501 Note: this filter is slow. For faster processing you should use a
510 aeval=val(ch)/2:c=same
514 Invert phase of the second channel:
523 Apply fade-in/out effect to input audio.
525 A description of the accepted parameters follows.
529 Specify the effect type, can be either @code{in} for fade-in, or
530 @code{out} for a fade-out effect. Default is @code{in}.
532 @item start_sample, ss
533 Specify the number of the start sample for starting to apply the fade
534 effect. Default is 0.
537 Specify the number of samples for which the fade effect has to last. At
538 the end of the fade-in effect the output audio will have the same
539 volume as the input audio, at the end of the fade-out transition
540 the output audio will be silence. Default is 44100.
543 Specify the start time of the fade effect. Default is 0.
544 The value must be specified as a time duration; see
545 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
546 for the accepted syntax.
547 If set this option is used instead of @var{start_sample}.
550 Specify the duration of the fade effect. See
551 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
552 for the accepted syntax.
553 At the end of the fade-in effect the output audio will have the same
554 volume as the input audio, at the end of the fade-out transition
555 the output audio will be silence.
556 By default the duration is determined by @var{nb_samples}.
557 If set this option is used instead of @var{nb_samples}.
560 Set curve for fade transition.
562 It accepts the following values:
565 select triangular, linear slope (default)
567 select quarter of sine wave
569 select half of sine wave
571 select exponential sine wave
575 select inverted parabola
589 select inverted quarter of sine wave
591 select inverted half of sine wave
593 select double-exponential seat
595 select double-exponential sigmoid
603 Fade in first 15 seconds of audio:
609 Fade out last 25 seconds of a 900 seconds audio:
611 afade=t=out:st=875:d=25
618 Set output format constraints for the input audio. The framework will
619 negotiate the most appropriate format to minimize conversions.
621 It accepts the following parameters:
625 A '|'-separated list of requested sample formats.
628 A '|'-separated list of requested sample rates.
630 @item channel_layouts
631 A '|'-separated list of requested channel layouts.
633 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
634 for the required syntax.
637 If a parameter is omitted, all values are allowed.
639 Force the output to either unsigned 8-bit or signed 16-bit stereo
641 aformat=sample_fmts=u8|s16:channel_layouts=stereo
646 A gate is mainly used to reduce lower parts of a signal. This kind of signal
647 processing reduces disturbing noise between useful signals.
649 Gating is done by detecting the volume below a chosen level @var{threshold}
650 and divide it by the factor set with @var{ratio}. The bottom of the noise
651 floor is set via @var{range}. Because an exact manipulation of the signal
652 would cause distortion of the waveform the reduction can be levelled over
653 time. This is done by setting @var{attack} and @var{release}.
655 @var{attack} determines how long the signal has to fall below the threshold
656 before any reduction will occur and @var{release} sets the time the signal
657 has to raise above the threshold to reduce the reduction again.
658 Shorter signals than the chosen attack time will be left untouched.
662 Set input level before filtering.
665 Set the level of gain reduction when the signal is below the threshold.
668 If a signal rises above this level the gain reduction is released.
671 Set a ratio about which the signal is reduced.
674 Amount of milliseconds the signal has to rise above the threshold before gain
678 Amount of milliseconds the signal has to fall below the threshold before the
679 reduction is increased again.
682 Set amount of amplification of signal after processing.
685 Curve the sharp knee around the threshold to enter gain reduction more softly.
688 Choose if exact signal should be taken for detection or an RMS like one.
691 Choose if the average level between all channels or the louder channel affects
697 The limiter prevents input signal from raising over a desired threshold.
698 This limiter uses lookahead technology to prevent your signal from distorting.
699 It means that there is a small delay after signal is processed. Keep in mind
700 that the delay it produces is the attack time you set.
702 The filter accepts the following options:
706 Don't let signals above this level pass the limiter. The removed amplitude is
707 added automatically. Default is 1.
710 The limiter will reach its attenuation level in this amount of time in
711 milliseconds. Default is 5 milliseconds.
714 Come back from limiting to attenuation 1.0 in this amount of milliseconds.
715 Default is 50 milliseconds.
718 When gain reduction is always needed ASC takes care of releasing to an
719 average reduction level rather than reaching a reduction of 0 in the release
723 Select how much the release time is affected by ASC, 0 means nearly no changes
724 in release time while 1 produces higher release times.
727 Depending on picked setting it is recommended to upsample input 2x or 4x times
728 with @ref{aresample} before applying this filter.
732 Apply a two-pole all-pass filter with central frequency (in Hz)
733 @var{frequency}, and filter-width @var{width}.
734 An all-pass filter changes the audio's frequency to phase relationship
735 without changing its frequency to amplitude relationship.
737 The filter accepts the following options:
744 Set method to specify band-width of filter.
757 Specify the band-width of a filter in width_type units.
763 Merge two or more audio streams into a single multi-channel stream.
765 The filter accepts the following options:
770 Set the number of inputs. Default is 2.
774 If the channel layouts of the inputs are disjoint, and therefore compatible,
775 the channel layout of the output will be set accordingly and the channels
776 will be reordered as necessary. If the channel layouts of the inputs are not
777 disjoint, the output will have all the channels of the first input then all
778 the channels of the second input, in that order, and the channel layout of
779 the output will be the default value corresponding to the total number of
782 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
783 is FC+BL+BR, then the output will be in 5.1, with the channels in the
784 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
785 first input, b1 is the first channel of the second input).
787 On the other hand, if both input are in stereo, the output channels will be
788 in the default order: a1, a2, b1, b2, and the channel layout will be
789 arbitrarily set to 4.0, which may or may not be the expected value.
791 All inputs must have the same sample rate, and format.
793 If inputs do not have the same duration, the output will stop with the
800 Merge two mono files into a stereo stream:
802 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
806 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
808 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
814 Mixes multiple audio inputs into a single output.
816 Note that this filter only supports float samples (the @var{amerge}
817 and @var{pan} audio filters support many formats). If the @var{amix}
818 input has integer samples then @ref{aresample} will be automatically
819 inserted to perform the conversion to float samples.
823 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
825 will mix 3 input audio streams to a single output with the same duration as the
826 first input and a dropout transition time of 3 seconds.
828 It accepts the following parameters:
832 The number of inputs. If unspecified, it defaults to 2.
835 How to determine the end-of-stream.
839 The duration of the longest input. (default)
842 The duration of the shortest input.
845 The duration of the first input.
849 @item dropout_transition
850 The transition time, in seconds, for volume renormalization when an input
851 stream ends. The default value is 2 seconds.
857 Pass the audio source unchanged to the output.
861 Pad the end of an audio stream with silence.
863 This can be used together with @command{ffmpeg} @option{-shortest} to
864 extend audio streams to the same length as the video stream.
866 A description of the accepted options follows.
870 Set silence packet size. Default value is 4096.
873 Set the number of samples of silence to add to the end. After the
874 value is reached, the stream is terminated. This option is mutually
875 exclusive with @option{whole_len}.
878 Set the minimum total number of samples in the output audio stream. If
879 the value is longer than the input audio length, silence is added to
880 the end, until the value is reached. This option is mutually exclusive
881 with @option{pad_len}.
884 If neither the @option{pad_len} nor the @option{whole_len} option is
885 set, the filter will add silence to the end of the input stream
892 Add 1024 samples of silence to the end of the input:
898 Make sure the audio output will contain at least 10000 samples, pad
899 the input with silence if required:
905 Use @command{ffmpeg} to pad the audio input with silence, so that the
906 video stream will always result the shortest and will be converted
907 until the end in the output file when using the @option{shortest}
910 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
915 Add a phasing effect to the input audio.
917 A phaser filter creates series of peaks and troughs in the frequency spectrum.
918 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
920 A description of the accepted parameters follows.
924 Set input gain. Default is 0.4.
927 Set output gain. Default is 0.74
930 Set delay in milliseconds. Default is 3.0.
933 Set decay. Default is 0.4.
936 Set modulation speed in Hz. Default is 0.5.
939 Set modulation type. Default is triangular.
941 It accepts the following values:
951 Resample the input audio to the specified parameters, using the
952 libswresample library. If none are specified then the filter will
953 automatically convert between its input and output.
955 This filter is also able to stretch/squeeze the audio data to make it match
956 the timestamps or to inject silence / cut out audio to make it match the
957 timestamps, do a combination of both or do neither.
959 The filter accepts the syntax
960 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
961 expresses a sample rate and @var{resampler_options} is a list of
962 @var{key}=@var{value} pairs, separated by ":". See the
963 ffmpeg-resampler manual for the complete list of supported options.
969 Resample the input audio to 44100Hz:
975 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
976 samples per second compensation:
982 @section asetnsamples
984 Set the number of samples per each output audio frame.
986 The last output packet may contain a different number of samples, as
987 the filter will flush all the remaining samples when the input audio
990 The filter accepts the following options:
994 @item nb_out_samples, n
995 Set the number of frames per each output audio frame. The number is
996 intended as the number of samples @emph{per each channel}.
997 Default value is 1024.
1000 If set to 1, the filter will pad the last audio frame with zeroes, so
1001 that the last frame will contain the same number of samples as the
1002 previous ones. Default value is 1.
1005 For example, to set the number of per-frame samples to 1234 and
1006 disable padding for the last frame, use:
1008 asetnsamples=n=1234:p=0
1013 Set the sample rate without altering the PCM data.
1014 This will result in a change of speed and pitch.
1016 The filter accepts the following options:
1019 @item sample_rate, r
1020 Set the output sample rate. Default is 44100 Hz.
1025 Show a line containing various information for each input audio frame.
1026 The input audio is not modified.
1028 The shown line contains a sequence of key/value pairs of the form
1029 @var{key}:@var{value}.
1031 The following values are shown in the output:
1035 The (sequential) number of the input frame, starting from 0.
1038 The presentation timestamp of the input frame, in time base units; the time base
1039 depends on the filter input pad, and is usually 1/@var{sample_rate}.
1042 The presentation timestamp of the input frame in seconds.
1045 position of the frame in the input stream, -1 if this information in
1046 unavailable and/or meaningless (for example in case of synthetic audio)
1055 The sample rate for the audio frame.
1058 The number of samples (per channel) in the frame.
1061 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
1062 audio, the data is treated as if all the planes were concatenated.
1064 @item plane_checksums
1065 A list of Adler-32 checksums for each data plane.
1071 Display time domain statistical information about the audio channels.
1072 Statistics are calculated and displayed for each audio channel and,
1073 where applicable, an overall figure is also given.
1075 It accepts the following option:
1078 Short window length in seconds, used for peak and trough RMS measurement.
1079 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
1083 Set metadata injection. All the metadata keys are prefixed with @code{lavfi.astats.X},
1084 where @code{X} is channel number starting from 1 or string @code{Overall}. Default is
1087 Available keys for each channel are:
1118 For example full key look like this @code{lavfi.astats.1.DC_offset} or
1119 this @code{lavfi.astats.Overall.Peak_count}.
1121 For description what each key means read below.
1124 Set number of frame after which stats are going to be recalculated.
1125 Default is disabled.
1128 A description of each shown parameter follows:
1132 Mean amplitude displacement from zero.
1135 Minimal sample level.
1138 Maximal sample level.
1140 @item Min difference
1141 Minimal difference between two consecutive samples.
1143 @item Max difference
1144 Maximal difference between two consecutive samples.
1146 @item Mean difference
1147 Mean difference between two consecutive samples.
1148 The average of each difference between two consecutive samples.
1152 Standard peak and RMS level measured in dBFS.
1156 Peak and trough values for RMS level measured over a short window.
1159 Standard ratio of peak to RMS level (note: not in dB).
1162 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
1163 (i.e. either @var{Min level} or @var{Max level}).
1166 Number of occasions (not the number of samples) that the signal attained either
1167 @var{Min level} or @var{Max level}.
1170 Overall bit depth of audio. Number of bits used for each sample.
1175 Synchronize audio data with timestamps by squeezing/stretching it and/or
1176 dropping samples/adding silence when needed.
1178 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1180 It accepts the following parameters:
1184 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1185 by default. When disabled, time gaps are covered with silence.
1188 The minimum difference between timestamps and audio data (in seconds) to trigger
1189 adding/dropping samples. The default value is 0.1. If you get an imperfect
1190 sync with this filter, try setting this parameter to 0.
1193 The maximum compensation in samples per second. Only relevant with compensate=1.
1194 The default value is 500.
1197 Assume that the first PTS should be this value. The time base is 1 / sample
1198 rate. This allows for padding/trimming at the start of the stream. By default,
1199 no assumption is made about the first frame's expected PTS, so no padding or
1200 trimming is done. For example, this could be set to 0 to pad the beginning with
1201 silence if an audio stream starts after the video stream or to trim any samples
1202 with a negative PTS due to encoder delay.
1210 The filter accepts exactly one parameter, the audio tempo. If not
1211 specified then the filter will assume nominal 1.0 tempo. Tempo must
1212 be in the [0.5, 2.0] range.
1214 @subsection Examples
1218 Slow down audio to 80% tempo:
1224 To speed up audio to 125% tempo:
1232 Trim the input so that the output contains one continuous subpart of the input.
1234 It accepts the following parameters:
1237 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1238 sample with the timestamp @var{start} will be the first sample in the output.
1241 Specify time of the first audio sample that will be dropped, i.e. the
1242 audio sample immediately preceding the one with the timestamp @var{end} will be
1243 the last sample in the output.
1246 Same as @var{start}, except this option sets the start timestamp in samples
1250 Same as @var{end}, except this option sets the end timestamp in samples instead
1254 The maximum duration of the output in seconds.
1257 The number of the first sample that should be output.
1260 The number of the first sample that should be dropped.
1263 @option{start}, @option{end}, and @option{duration} are expressed as time
1264 duration specifications; see
1265 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1267 Note that the first two sets of the start/end options and the @option{duration}
1268 option look at the frame timestamp, while the _sample options simply count the
1269 samples that pass through the filter. So start/end_pts and start/end_sample will
1270 give different results when the timestamps are wrong, inexact or do not start at
1271 zero. Also note that this filter does not modify the timestamps. If you wish
1272 to have the output timestamps start at zero, insert the asetpts filter after the
1275 If multiple start or end options are set, this filter tries to be greedy and
1276 keep all samples that match at least one of the specified constraints. To keep
1277 only the part that matches all the constraints at once, chain multiple atrim
1280 The defaults are such that all the input is kept. So it is possible to set e.g.
1281 just the end values to keep everything before the specified time.
1286 Drop everything except the second minute of input:
1288 ffmpeg -i INPUT -af atrim=60:120
1292 Keep only the first 1000 samples:
1294 ffmpeg -i INPUT -af atrim=end_sample=1000
1301 Apply a two-pole Butterworth band-pass filter with central
1302 frequency @var{frequency}, and (3dB-point) band-width width.
1303 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1304 instead of the default: constant 0dB peak gain.
1305 The filter roll off at 6dB per octave (20dB per decade).
1307 The filter accepts the following options:
1311 Set the filter's central frequency. Default is @code{3000}.
1314 Constant skirt gain if set to 1. Defaults to 0.
1317 Set method to specify band-width of filter.
1330 Specify the band-width of a filter in width_type units.
1335 Apply a two-pole Butterworth band-reject filter with central
1336 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1337 The filter roll off at 6dB per octave (20dB per decade).
1339 The filter accepts the following options:
1343 Set the filter's central frequency. Default is @code{3000}.
1346 Set method to specify band-width of filter.
1359 Specify the band-width of a filter in width_type units.
1364 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1365 shelving filter with a response similar to that of a standard
1366 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1368 The filter accepts the following options:
1372 Give the gain at 0 Hz. Its useful range is about -20
1373 (for a large cut) to +20 (for a large boost).
1374 Beware of clipping when using a positive gain.
1377 Set the filter's central frequency and so can be used
1378 to extend or reduce the frequency range to be boosted or cut.
1379 The default value is @code{100} Hz.
1382 Set method to specify band-width of filter.
1395 Determine how steep is the filter's shelf transition.
1400 Apply a biquad IIR filter with the given coefficients.
1401 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1402 are the numerator and denominator coefficients respectively.
1405 Bauer stereo to binaural transformation, which improves headphone listening of
1406 stereo audio records.
1408 It accepts the following parameters:
1412 Pre-defined crossfeed level.
1416 Default level (fcut=700, feed=50).
1419 Chu Moy circuit (fcut=700, feed=60).
1422 Jan Meier circuit (fcut=650, feed=95).
1427 Cut frequency (in Hz).
1436 Remap input channels to new locations.
1438 It accepts the following parameters:
1440 @item channel_layout
1441 The channel layout of the output stream.
1444 Map channels from input to output. The argument is a '|'-separated list of
1445 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1446 @var{in_channel} form. @var{in_channel} can be either the name of the input
1447 channel (e.g. FL for front left) or its index in the input channel layout.
1448 @var{out_channel} is the name of the output channel or its index in the output
1449 channel layout. If @var{out_channel} is not given then it is implicitly an
1450 index, starting with zero and increasing by one for each mapping.
1453 If no mapping is present, the filter will implicitly map input channels to
1454 output channels, preserving indices.
1456 For example, assuming a 5.1+downmix input MOV file,
1458 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1460 will create an output WAV file tagged as stereo from the downmix channels of
1463 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1465 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav
1468 @section channelsplit
1470 Split each channel from an input audio stream into a separate output stream.
1472 It accepts the following parameters:
1474 @item channel_layout
1475 The channel layout of the input stream. The default is "stereo".
1478 For example, assuming a stereo input MP3 file,
1480 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1482 will create an output Matroska file with two audio streams, one containing only
1483 the left channel and the other the right channel.
1485 Split a 5.1 WAV file into per-channel files:
1487 ffmpeg -i in.wav -filter_complex
1488 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1489 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1490 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1495 Add a chorus effect to the audio.
1497 Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
1499 Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
1500 constant, with chorus, it is varied using using sinusoidal or triangular modulation.
1501 The modulation depth defines the range the modulated delay is played before or after
1502 the delay. Hence the delayed sound will sound slower or faster, that is the delayed
1503 sound tuned around the original one, like in a chorus where some vocals are slightly
1506 It accepts the following parameters:
1509 Set input gain. Default is 0.4.
1512 Set output gain. Default is 0.4.
1515 Set delays. A typical delay is around 40ms to 60ms.
1527 @subsection Examples
1533 chorus=0.7:0.9:55:0.4:0.25:2
1539 chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
1543 Fuller sounding chorus with three delays:
1545 chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3
1550 Compress or expand the audio's dynamic range.
1552 It accepts the following parameters:
1558 A list of times in seconds for each channel over which the instantaneous level
1559 of the input signal is averaged to determine its volume. @var{attacks} refers to
1560 increase of volume and @var{decays} refers to decrease of volume. For most
1561 situations, the attack time (response to the audio getting louder) should be
1562 shorter than the decay time, because the human ear is more sensitive to sudden
1563 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1564 a typical value for decay is 0.8 seconds.
1565 If specified number of attacks & decays is lower than number of channels, the last
1566 set attack/decay will be used for all remaining channels.
1569 A list of points for the transfer function, specified in dB relative to the
1570 maximum possible signal amplitude. Each key points list must be defined using
1571 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1572 @code{x0/y0 x1/y1 x2/y2 ....}
1574 The input values must be in strictly increasing order but the transfer function
1575 does not have to be monotonically rising. The point @code{0/0} is assumed but
1576 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1577 function are @code{-70/-70|-60/-20}.
1580 Set the curve radius in dB for all joints. It defaults to 0.01.
1583 Set the additional gain in dB to be applied at all points on the transfer
1584 function. This allows for easy adjustment of the overall gain.
1588 Set an initial volume, in dB, to be assumed for each channel when filtering
1589 starts. This permits the user to supply a nominal level initially, so that, for
1590 example, a very large gain is not applied to initial signal levels before the
1591 companding has begun to operate. A typical value for audio which is initially
1592 quiet is -90 dB. It defaults to 0.
1595 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1596 delayed before being fed to the volume adjuster. Specifying a delay
1597 approximately equal to the attack/decay times allows the filter to effectively
1598 operate in predictive rather than reactive mode. It defaults to 0.
1602 @subsection Examples
1606 Make music with both quiet and loud passages suitable for listening to in a
1609 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1612 Another example for audio with whisper and explosion parts:
1614 compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
1618 A noise gate for when the noise is at a lower level than the signal:
1620 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1624 Here is another noise gate, this time for when the noise is at a higher level
1625 than the signal (making it, in some ways, similar to squelch):
1627 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1632 Apply a DC shift to the audio.
1634 This can be useful to remove a DC offset (caused perhaps by a hardware problem
1635 in the recording chain) from the audio. The effect of a DC offset is reduced
1636 headroom and hence volume. The @ref{astats} filter can be used to determine if
1637 a signal has a DC offset.
1641 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
1645 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
1646 used to prevent clipping.
1650 Dynamic Audio Normalizer.
1652 This filter applies a certain amount of gain to the input audio in order
1653 to bring its peak magnitude to a target level (e.g. 0 dBFS). However, in
1654 contrast to more "simple" normalization algorithms, the Dynamic Audio
1655 Normalizer *dynamically* re-adjusts the gain factor to the input audio.
1656 This allows for applying extra gain to the "quiet" sections of the audio
1657 while avoiding distortions or clipping the "loud" sections. In other words:
1658 The Dynamic Audio Normalizer will "even out" the volume of quiet and loud
1659 sections, in the sense that the volume of each section is brought to the
1660 same target level. Note, however, that the Dynamic Audio Normalizer achieves
1661 this goal *without* applying "dynamic range compressing". It will retain 100%
1662 of the dynamic range *within* each section of the audio file.
1666 Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.
1667 Default is 500 milliseconds.
1668 The Dynamic Audio Normalizer processes the input audio in small chunks,
1669 referred to as frames. This is required, because a peak magnitude has no
1670 meaning for just a single sample value. Instead, we need to determine the
1671 peak magnitude for a contiguous sequence of sample values. While a "standard"
1672 normalizer would simply use the peak magnitude of the complete file, the
1673 Dynamic Audio Normalizer determines the peak magnitude individually for each
1674 frame. The length of a frame is specified in milliseconds. By default, the
1675 Dynamic Audio Normalizer uses a frame length of 500 milliseconds, which has
1676 been found to give good results with most files.
1677 Note that the exact frame length, in number of samples, will be determined
1678 automatically, based on the sampling rate of the individual input audio file.
1681 Set the Gaussian filter window size. In range from 3 to 301, must be odd
1682 number. Default is 31.
1683 Probably the most important parameter of the Dynamic Audio Normalizer is the
1684 @code{window size} of the Gaussian smoothing filter. The filter's window size
1685 is specified in frames, centered around the current frame. For the sake of
1686 simplicity, this must be an odd number. Consequently, the default value of 31
1687 takes into account the current frame, as well as the 15 preceding frames and
1688 the 15 subsequent frames. Using a larger window results in a stronger
1689 smoothing effect and thus in less gain variation, i.e. slower gain
1690 adaptation. Conversely, using a smaller window results in a weaker smoothing
1691 effect and thus in more gain variation, i.e. faster gain adaptation.
1692 In other words, the more you increase this value, the more the Dynamic Audio
1693 Normalizer will behave like a "traditional" normalization filter. On the
1694 contrary, the more you decrease this value, the more the Dynamic Audio
1695 Normalizer will behave like a dynamic range compressor.
1698 Set the target peak value. This specifies the highest permissible magnitude
1699 level for the normalized audio input. This filter will try to approach the
1700 target peak magnitude as closely as possible, but at the same time it also
1701 makes sure that the normalized signal will never exceed the peak magnitude.
1702 A frame's maximum local gain factor is imposed directly by the target peak
1703 magnitude. The default value is 0.95 and thus leaves a headroom of 5%*.
1704 It is not recommended to go above this value.
1707 Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.
1708 The Dynamic Audio Normalizer determines the maximum possible (local) gain
1709 factor for each input frame, i.e. the maximum gain factor that does not
1710 result in clipping or distortion. The maximum gain factor is determined by
1711 the frame's highest magnitude sample. However, the Dynamic Audio Normalizer
1712 additionally bounds the frame's maximum gain factor by a predetermined
1713 (global) maximum gain factor. This is done in order to avoid excessive gain
1714 factors in "silent" or almost silent frames. By default, the maximum gain
1715 factor is 10.0, For most inputs the default value should be sufficient and
1716 it usually is not recommended to increase this value. Though, for input
1717 with an extremely low overall volume level, it may be necessary to allow even
1718 higher gain factors. Note, however, that the Dynamic Audio Normalizer does
1719 not simply apply a "hard" threshold (i.e. cut off values above the threshold).
1720 Instead, a "sigmoid" threshold function will be applied. This way, the
1721 gain factors will smoothly approach the threshold value, but never exceed that
1725 Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.
1726 By default, the Dynamic Audio Normalizer performs "peak" normalization.
1727 This means that the maximum local gain factor for each frame is defined
1728 (only) by the frame's highest magnitude sample. This way, the samples can
1729 be amplified as much as possible without exceeding the maximum signal
1730 level, i.e. without clipping. Optionally, however, the Dynamic Audio
1731 Normalizer can also take into account the frame's root mean square,
1732 abbreviated RMS. In electrical engineering, the RMS is commonly used to
1733 determine the power of a time-varying signal. It is therefore considered
1734 that the RMS is a better approximation of the "perceived loudness" than
1735 just looking at the signal's peak magnitude. Consequently, by adjusting all
1736 frames to a constant RMS value, a uniform "perceived loudness" can be
1737 established. If a target RMS value has been specified, a frame's local gain
1738 factor is defined as the factor that would result in exactly that RMS value.
1739 Note, however, that the maximum local gain factor is still restricted by the
1740 frame's highest magnitude sample, in order to prevent clipping.
1743 Enable channels coupling. By default is enabled.
1744 By default, the Dynamic Audio Normalizer will amplify all channels by the same
1745 amount. This means the same gain factor will be applied to all channels, i.e.
1746 the maximum possible gain factor is determined by the "loudest" channel.
1747 However, in some recordings, it may happen that the volume of the different
1748 channels is uneven, e.g. one channel may be "quieter" than the other one(s).
1749 In this case, this option can be used to disable the channel coupling. This way,
1750 the gain factor will be determined independently for each channel, depending
1751 only on the individual channel's highest magnitude sample. This allows for
1752 harmonizing the volume of the different channels.
1755 Enable DC bias correction. By default is disabled.
1756 An audio signal (in the time domain) is a sequence of sample values.
1757 In the Dynamic Audio Normalizer these sample values are represented in the
1758 -1.0 to 1.0 range, regardless of the original input format. Normally, the
1759 audio signal, or "waveform", should be centered around the zero point.
1760 That means if we calculate the mean value of all samples in a file, or in a
1761 single frame, then the result should be 0.0 or at least very close to that
1762 value. If, however, there is a significant deviation of the mean value from
1763 0.0, in either positive or negative direction, this is referred to as a
1764 DC bias or DC offset. Since a DC bias is clearly undesirable, the Dynamic
1765 Audio Normalizer provides optional DC bias correction.
1766 With DC bias correction enabled, the Dynamic Audio Normalizer will determine
1767 the mean value, or "DC correction" offset, of each input frame and subtract
1768 that value from all of the frame's sample values which ensures those samples
1769 are centered around 0.0 again. Also, in order to avoid "gaps" at the frame
1770 boundaries, the DC correction offset values will be interpolated smoothly
1771 between neighbouring frames.
1774 Enable alternative boundary mode. By default is disabled.
1775 The Dynamic Audio Normalizer takes into account a certain neighbourhood
1776 around each frame. This includes the preceding frames as well as the
1777 subsequent frames. However, for the "boundary" frames, located at the very
1778 beginning and at the very end of the audio file, not all neighbouring
1779 frames are available. In particular, for the first few frames in the audio
1780 file, the preceding frames are not known. And, similarly, for the last few
1781 frames in the audio file, the subsequent frames are not known. Thus, the
1782 question arises which gain factors should be assumed for the missing frames
1783 in the "boundary" region. The Dynamic Audio Normalizer implements two modes
1784 to deal with this situation. The default boundary mode assumes a gain factor
1785 of exactly 1.0 for the missing frames, resulting in a smooth "fade in" and
1786 "fade out" at the beginning and at the end of the input, respectively.
1789 Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
1790 By default, the Dynamic Audio Normalizer does not apply "traditional"
1791 compression. This means that signal peaks will not be pruned and thus the
1792 full dynamic range will be retained within each local neighbourhood. However,
1793 in some cases it may be desirable to combine the Dynamic Audio Normalizer's
1794 normalization algorithm with a more "traditional" compression.
1795 For this purpose, the Dynamic Audio Normalizer provides an optional compression
1796 (thresholding) function. If (and only if) the compression feature is enabled,
1797 all input frames will be processed by a soft knee thresholding function prior
1798 to the actual normalization process. Put simply, the thresholding function is
1799 going to prune all samples whose magnitude exceeds a certain threshold value.
1800 However, the Dynamic Audio Normalizer does not simply apply a fixed threshold
1801 value. Instead, the threshold value will be adjusted for each individual
1803 In general, smaller parameters result in stronger compression, and vice versa.
1804 Values below 3.0 are not recommended, because audible distortion may appear.
1809 Make audio easier to listen to on headphones.
1811 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1812 so that when listened to on headphones the stereo image is moved from
1813 inside your head (standard for headphones) to outside and in front of
1814 the listener (standard for speakers).
1820 Apply a two-pole peaking equalisation (EQ) filter. With this
1821 filter, the signal-level at and around a selected frequency can
1822 be increased or decreased, whilst (unlike bandpass and bandreject
1823 filters) that at all other frequencies is unchanged.
1825 In order to produce complex equalisation curves, this filter can
1826 be given several times, each with a different central frequency.
1828 The filter accepts the following options:
1832 Set the filter's central frequency in Hz.
1835 Set method to specify band-width of filter.
1848 Specify the band-width of a filter in width_type units.
1851 Set the required gain or attenuation in dB.
1852 Beware of clipping when using a positive gain.
1855 @subsection Examples
1858 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1860 equalizer=f=1000:width_type=h:width=200:g=-10
1864 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1866 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1870 @section extrastereo
1872 Linearly increases the difference between left and right channels which
1873 adds some sort of "live" effect to playback.
1875 The filter accepts the following option:
1879 Sets the difference coefficient (default: 2.5). 0.0 means mono sound
1880 (average of both channels), with 1.0 sound will be unchanged, with
1881 -1.0 left and right channels will be swapped.
1884 Enable clipping. By default is enabled.
1888 Apply a flanging effect to the audio.
1890 The filter accepts the following options:
1894 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1897 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1900 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1904 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1905 Default value is 71.
1908 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1911 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1912 Default value is @var{sinusoidal}.
1915 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1916 Default value is 25.
1919 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1920 Default is @var{linear}.
1925 Apply a high-pass filter with 3dB point frequency.
1926 The filter can be either single-pole, or double-pole (the default).
1927 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1929 The filter accepts the following options:
1933 Set frequency in Hz. Default is 3000.
1936 Set number of poles. Default is 2.
1939 Set method to specify band-width of filter.
1952 Specify the band-width of a filter in width_type units.
1953 Applies only to double-pole filter.
1954 The default is 0.707q and gives a Butterworth response.
1959 Join multiple input streams into one multi-channel stream.
1961 It accepts the following parameters:
1965 The number of input streams. It defaults to 2.
1967 @item channel_layout
1968 The desired output channel layout. It defaults to stereo.
1971 Map channels from inputs to output. The argument is a '|'-separated list of
1972 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1973 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1974 can be either the name of the input channel (e.g. FL for front left) or its
1975 index in the specified input stream. @var{out_channel} is the name of the output
1979 The filter will attempt to guess the mappings when they are not specified
1980 explicitly. It does so by first trying to find an unused matching input channel
1981 and if that fails it picks the first unused input channel.
1983 Join 3 inputs (with properly set channel layouts):
1985 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1988 Build a 5.1 output from 6 single-channel streams:
1990 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1991 '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'
1997 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1999 To enable compilation of this filter you need to configure FFmpeg with
2000 @code{--enable-ladspa}.
2004 Specifies the name of LADSPA plugin library to load. If the environment
2005 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
2006 each one of the directories specified by the colon separated list in
2007 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
2008 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
2009 @file{/usr/lib/ladspa/}.
2012 Specifies the plugin within the library. Some libraries contain only
2013 one plugin, but others contain many of them. If this is not set filter
2014 will list all available plugins within the specified library.
2017 Set the '|' separated list of controls which are zero or more floating point
2018 values that determine the behavior of the loaded plugin (for example delay,
2020 Controls need to be defined using the following syntax:
2021 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
2022 @var{valuei} is the value set on the @var{i}-th control.
2023 Alternatively they can be also defined using the following syntax:
2024 @var{value0}|@var{value1}|@var{value2}|..., where
2025 @var{valuei} is the value set on the @var{i}-th control.
2026 If @option{controls} is set to @code{help}, all available controls and
2027 their valid ranges are printed.
2029 @item sample_rate, s
2030 Specify the sample rate, default to 44100. Only used if plugin have
2034 Set the number of samples per channel per each output frame, default
2035 is 1024. Only used if plugin have zero inputs.
2038 Set the minimum duration of the sourced audio. See
2039 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2040 for the accepted syntax.
2041 Note that the resulting duration may be greater than the specified duration,
2042 as the generated audio is always cut at the end of a complete frame.
2043 If not specified, or the expressed duration is negative, the audio is
2044 supposed to be generated forever.
2045 Only used if plugin have zero inputs.
2049 @subsection Examples
2053 List all available plugins within amp (LADSPA example plugin) library:
2059 List all available controls and their valid ranges for @code{vcf_notch}
2060 plugin from @code{VCF} library:
2062 ladspa=f=vcf:p=vcf_notch:c=help
2066 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
2069 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2073 Add reverberation to the audio using TAP-plugins
2074 (Tom's Audio Processing plugins):
2076 ladspa=file=tap_reverb:tap_reverb
2080 Generate white noise, with 0.2 amplitude:
2082 ladspa=file=cmt:noise_source_white:c=c0=.2
2086 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2087 @code{C* Audio Plugin Suite} (CAPS) library:
2089 ladspa=file=caps:Click:c=c1=20'
2093 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2095 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2099 Increase volume by 20dB using fast lookahead limiter from Steve Harris
2100 @code{SWH Plugins} collection:
2102 ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2
2106 Attenuate low frequencies using Multiband EQ from Steve Harris
2107 @code{SWH Plugins} collection:
2109 ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0
2113 @subsection Commands
2115 This filter supports the following commands:
2118 Modify the @var{N}-th control value.
2120 If the specified value is not valid, it is ignored and prior one is kept.
2125 Apply a low-pass filter with 3dB point frequency.
2126 The filter can be either single-pole or double-pole (the default).
2127 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2129 The filter accepts the following options:
2133 Set frequency in Hz. Default is 500.
2136 Set number of poles. Default is 2.
2139 Set method to specify band-width of filter.
2152 Specify the band-width of a filter in width_type units.
2153 Applies only to double-pole filter.
2154 The default is 0.707q and gives a Butterworth response.
2160 Mix channels with specific gain levels. The filter accepts the output
2161 channel layout followed by a set of channels definitions.
2163 This filter is also designed to efficiently remap the channels of an audio
2166 The filter accepts parameters of the form:
2167 "@var{l}|@var{outdef}|@var{outdef}|..."
2171 output channel layout or number of channels
2174 output channel specification, of the form:
2175 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2178 output channel to define, either a channel name (FL, FR, etc.) or a channel
2179 number (c0, c1, etc.)
2182 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2185 input channel to use, see out_name for details; it is not possible to mix
2186 named and numbered input channels
2189 If the `=' in a channel specification is replaced by `<', then the gains for
2190 that specification will be renormalized so that the total is 1, thus
2191 avoiding clipping noise.
2193 @subsection Mixing examples
2195 For example, if you want to down-mix from stereo to mono, but with a bigger
2196 factor for the left channel:
2198 pan=1c|c0=0.9*c0+0.1*c1
2201 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2202 7-channels surround:
2204 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2207 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2208 that should be preferred (see "-ac" option) unless you have very specific
2211 @subsection Remapping examples
2213 The channel remapping will be effective if, and only if:
2216 @item gain coefficients are zeroes or ones,
2217 @item only one input per channel output,
2220 If all these conditions are satisfied, the filter will notify the user ("Pure
2221 channel mapping detected"), and use an optimized and lossless method to do the
2224 For example, if you have a 5.1 source and want a stereo audio stream by
2225 dropping the extra channels:
2227 pan="stereo| c0=FL | c1=FR"
2230 Given the same source, you can also switch front left and front right channels
2231 and keep the input channel layout:
2233 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2236 If the input is a stereo audio stream, you can mute the front left channel (and
2237 still keep the stereo channel layout) with:
2242 Still with a stereo audio stream input, you can copy the right channel in both
2243 front left and right:
2245 pan="stereo| c0=FR | c1=FR"
2250 ReplayGain scanner filter. This filter takes an audio stream as an input and
2251 outputs it unchanged.
2252 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2256 Convert the audio sample format, sample rate and channel layout. It is
2257 not meant to be used directly.
2260 Apply time-stretching and pitch-shifting with librubberband.
2262 The filter accepts the following options:
2266 Set tempo scale factor.
2269 Set pitch scale factor.
2272 Set transients detector.
2273 Possible values are:
2282 Possible values are:
2291 Possible values are:
2298 Set processing window size.
2299 Possible values are:
2308 Possible values are:
2315 Enable formant preservation when shift pitching.
2316 Possible values are:
2324 Possible values are:
2333 Possible values are:
2340 @section sidechaincompress
2342 This filter acts like normal compressor but has the ability to compress
2343 detected signal using second input signal.
2344 It needs two input streams and returns one output stream.
2345 First input stream will be processed depending on second stream signal.
2346 The filtered signal then can be filtered with other filters in later stages of
2347 processing. See @ref{pan} and @ref{amerge} filter.
2349 The filter accepts the following options:
2353 If a signal of second stream raises above this level it will affect the gain
2354 reduction of first stream.
2355 By default is 0.125. Range is between 0.00097563 and 1.
2358 Set a ratio about which the signal is reduced. 1:2 means that if the level
2359 raised 4dB above the threshold, it will be only 2dB above after the reduction.
2360 Default is 2. Range is between 1 and 20.
2363 Amount of milliseconds the signal has to rise above the threshold before gain
2364 reduction starts. Default is 20. Range is between 0.01 and 2000.
2367 Amount of milliseconds the signal has to fall below the threshold before
2368 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
2371 Set the amount by how much signal will be amplified after processing.
2372 Default is 2. Range is from 1 and 64.
2375 Curve the sharp knee around the threshold to enter gain reduction more softly.
2376 Default is 2.82843. Range is between 1 and 8.
2379 Choose if the @code{average} level between all channels of side-chain stream
2380 or the louder(@code{maximum}) channel of side-chain stream affects the
2381 reduction. Default is @code{average}.
2384 Should the exact signal be taken in case of @code{peak} or an RMS one in case
2385 of @code{rms}. Default is @code{rms} which is mainly smoother.
2388 @subsection Examples
2392 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
2393 depending on the signal of 2nd input and later compressed signal to be
2394 merged with 2nd input:
2396 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
2400 @section silencedetect
2402 Detect silence in an audio stream.
2404 This filter logs a message when it detects that the input audio volume is less
2405 or equal to a noise tolerance value for a duration greater or equal to the
2406 minimum detected noise duration.
2408 The printed times and duration are expressed in seconds.
2410 The filter accepts the following options:
2414 Set silence duration until notification (default is 2 seconds).
2417 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
2418 specified value) or amplitude ratio. Default is -60dB, or 0.001.
2421 @subsection Examples
2425 Detect 5 seconds of silence with -50dB noise tolerance:
2427 silencedetect=n=-50dB:d=5
2431 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
2432 tolerance in @file{silence.mp3}:
2434 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
2438 @section silenceremove
2440 Remove silence from the beginning, middle or end of the audio.
2442 The filter accepts the following options:
2446 This value is used to indicate if audio should be trimmed at beginning of
2447 the audio. A value of zero indicates no silence should be trimmed from the
2448 beginning. When specifying a non-zero value, it trims audio up until it
2449 finds non-silence. Normally, when trimming silence from beginning of audio
2450 the @var{start_periods} will be @code{1} but it can be increased to higher
2451 values to trim all audio up to specific count of non-silence periods.
2452 Default value is @code{0}.
2454 @item start_duration
2455 Specify the amount of time that non-silence must be detected before it stops
2456 trimming audio. By increasing the duration, bursts of noises can be treated
2457 as silence and trimmed off. Default value is @code{0}.
2459 @item start_threshold
2460 This indicates what sample value should be treated as silence. For digital
2461 audio, a value of @code{0} may be fine but for audio recorded from analog,
2462 you may wish to increase the value to account for background noise.
2463 Can be specified in dB (in case "dB" is appended to the specified value)
2464 or amplitude ratio. Default value is @code{0}.
2467 Set the count for trimming silence from the end of audio.
2468 To remove silence from the middle of a file, specify a @var{stop_periods}
2469 that is negative. This value is then treated as a positive value and is
2470 used to indicate the effect should restart processing as specified by
2471 @var{start_periods}, making it suitable for removing periods of silence
2472 in the middle of the audio.
2473 Default value is @code{0}.
2476 Specify a duration of silence that must exist before audio is not copied any
2477 more. By specifying a higher duration, silence that is wanted can be left in
2479 Default value is @code{0}.
2481 @item stop_threshold
2482 This is the same as @option{start_threshold} but for trimming silence from
2484 Can be specified in dB (in case "dB" is appended to the specified value)
2485 or amplitude ratio. Default value is @code{0}.
2488 This indicate that @var{stop_duration} length of audio should be left intact
2489 at the beginning of each period of silence.
2490 For example, if you want to remove long pauses between words but do not want
2491 to remove the pauses completely. Default value is @code{0}.
2495 @subsection Examples
2499 The following example shows how this filter can be used to start a recording
2500 that does not contain the delay at the start which usually occurs between
2501 pressing the record button and the start of the performance:
2503 silenceremove=1:5:0.02
2507 @section stereotools
2509 This filter has some handy utilities to manage stereo signals, for converting
2510 M/S stereo recordings to L/R signal while having control over the parameters
2511 or spreading the stereo image of master track.
2513 The filter accepts the following options:
2517 Set input level before filtering for both channels. Defaults is 1.
2518 Allowed range is from 0.015625 to 64.
2521 Set output level after filtering for both channels. Defaults is 1.
2522 Allowed range is from 0.015625 to 64.
2525 Set input balance between both channels. Default is 0.
2526 Allowed range is from -1 to 1.
2529 Set output balance between both channels. Default is 0.
2530 Allowed range is from -1 to 1.
2533 Enable softclipping. Results in analog distortion instead of harsh digital 0dB
2534 clipping. Disabled by default.
2537 Mute the left channel. Disabled by default.
2540 Mute the right channel. Disabled by default.
2543 Change the phase of the left channel. Disabled by default.
2546 Change the phase of the right channel. Disabled by default.
2549 Set stereo mode. Available values are:
2553 Left/Right to Left/Right, this is default.
2556 Left/Right to Mid/Side.
2559 Mid/Side to Left/Right.
2562 Left/Right to Left/Left.
2565 Left/Right to Right/Right.
2568 Left/Right to Left + Right.
2571 Left/Right to Right/Left.
2575 Set level of side signal. Default is 1.
2576 Allowed range is from 0.015625 to 64.
2579 Set balance of side signal. Default is 0.
2580 Allowed range is from -1 to 1.
2583 Set level of the middle signal. Default is 1.
2584 Allowed range is from 0.015625 to 64.
2587 Set middle signal pan. Default is 0. Allowed range is from -1 to 1.
2590 Set stereo base between mono and inversed channels. Default is 0.
2591 Allowed range is from -1 to 1.
2594 Set delay in milliseconds how much to delay left from right channel and
2595 vice versa. Default is 0. Allowed range is from -20 to 20.
2598 Set S/C level. Default is 1. Allowed range is from 1 to 100.
2601 Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
2604 @section stereowiden
2606 This filter enhance the stereo effect by suppressing signal common to both
2607 channels and by delaying the signal of left into right and vice versa,
2608 thereby widening the stereo effect.
2610 The filter accepts the following options:
2614 Time in milliseconds of the delay of left signal into right and vice versa.
2615 Default is 20 milliseconds.
2618 Amount of gain in delayed signal into right and vice versa. Gives a delay
2619 effect of left signal in right output and vice versa which gives widening
2620 effect. Default is 0.3.
2623 Cross feed of left into right with inverted phase. This helps in suppressing
2624 the mono. If the value is 1 it will cancel all the signal common to both
2625 channels. Default is 0.3.
2628 Set level of input signal of original channel. Default is 0.8.
2633 Boost or cut treble (upper) frequencies of the audio using a two-pole
2634 shelving filter with a response similar to that of a standard
2635 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
2637 The filter accepts the following options:
2641 Give the gain at whichever is the lower of ~22 kHz and the
2642 Nyquist frequency. Its useful range is about -20 (for a large cut)
2643 to +20 (for a large boost). Beware of clipping when using a positive gain.
2646 Set the filter's central frequency and so can be used
2647 to extend or reduce the frequency range to be boosted or cut.
2648 The default value is @code{3000} Hz.
2651 Set method to specify band-width of filter.
2664 Determine how steep is the filter's shelf transition.
2669 Sinusoidal amplitude modulation.
2671 The filter accepts the following options:
2675 Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
2676 (20 Hz or lower) will result in a tremolo effect.
2677 This filter may also be used as a ring modulator by specifying
2678 a modulation frequency higher than 20 Hz.
2679 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
2682 Depth of modulation as a percentage. Range is 0.0 - 1.0.
2683 Default value is 0.5.
2688 Sinusoidal phase modulation.
2690 The filter accepts the following options:
2694 Modulation frequency in Hertz.
2695 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
2698 Depth of modulation as a percentage. Range is 0.0 - 1.0.
2699 Default value is 0.5.
2704 Adjust the input audio volume.
2706 It accepts the following parameters:
2710 Set audio volume expression.
2712 Output values are clipped to the maximum value.
2714 The output audio volume is given by the relation:
2716 @var{output_volume} = @var{volume} * @var{input_volume}
2719 The default value for @var{volume} is "1.0".
2722 This parameter represents the mathematical precision.
2724 It determines which input sample formats will be allowed, which affects the
2725 precision of the volume scaling.
2729 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
2731 32-bit floating-point; this limits input sample format to FLT. (default)
2733 64-bit floating-point; this limits input sample format to DBL.
2737 Choose the behaviour on encountering ReplayGain side data in input frames.
2741 Remove ReplayGain side data, ignoring its contents (the default).
2744 Ignore ReplayGain side data, but leave it in the frame.
2747 Prefer the track gain, if present.
2750 Prefer the album gain, if present.
2753 @item replaygain_preamp
2754 Pre-amplification gain in dB to apply to the selected replaygain gain.
2756 Default value for @var{replaygain_preamp} is 0.0.
2759 Set when the volume expression is evaluated.
2761 It accepts the following values:
2764 only evaluate expression once during the filter initialization, or
2765 when the @samp{volume} command is sent
2768 evaluate expression for each incoming frame
2771 Default value is @samp{once}.
2774 The volume expression can contain the following parameters.
2778 frame number (starting at zero)
2781 @item nb_consumed_samples
2782 number of samples consumed by the filter
2784 number of samples in the current frame
2786 original frame position in the file
2792 PTS at start of stream
2794 time at start of stream
2800 last set volume value
2803 Note that when @option{eval} is set to @samp{once} only the
2804 @var{sample_rate} and @var{tb} variables are available, all other
2805 variables will evaluate to NAN.
2807 @subsection Commands
2809 This filter supports the following commands:
2812 Modify the volume expression.
2813 The command accepts the same syntax of the corresponding option.
2815 If the specified expression is not valid, it is kept at its current
2817 @item replaygain_noclip
2818 Prevent clipping by limiting the gain applied.
2820 Default value for @var{replaygain_noclip} is 1.
2824 @subsection Examples
2828 Halve the input audio volume:
2832 volume=volume=-6.0206dB
2835 In all the above example the named key for @option{volume} can be
2836 omitted, for example like in:
2842 Increase input audio power by 6 decibels using fixed-point precision:
2844 volume=volume=6dB:precision=fixed
2848 Fade volume after time 10 with an annihilation period of 5 seconds:
2850 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2854 @section volumedetect
2856 Detect the volume of the input video.
2858 The filter has no parameters. The input is not modified. Statistics about
2859 the volume will be printed in the log when the input stream end is reached.
2861 In particular it will show the mean volume (root mean square), maximum
2862 volume (on a per-sample basis), and the beginning of a histogram of the
2863 registered volume values (from the maximum value to a cumulated 1/1000 of
2866 All volumes are in decibels relative to the maximum PCM value.
2868 @subsection Examples
2870 Here is an excerpt of the output:
2872 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2873 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2874 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2875 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2876 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2877 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2878 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2879 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2880 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2886 The mean square energy is approximately -27 dB, or 10^-2.7.
2888 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2890 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2893 In other words, raising the volume by +4 dB does not cause any clipping,
2894 raising it by +5 dB causes clipping for 6 samples, etc.
2896 @c man end AUDIO FILTERS
2898 @chapter Audio Sources
2899 @c man begin AUDIO SOURCES
2901 Below is a description of the currently available audio sources.
2905 Buffer audio frames, and make them available to the filter chain.
2907 This source is mainly intended for a programmatic use, in particular
2908 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2910 It accepts the following parameters:
2914 The timebase which will be used for timestamps of submitted frames. It must be
2915 either a floating-point number or in @var{numerator}/@var{denominator} form.
2918 The sample rate of the incoming audio buffers.
2921 The sample format of the incoming audio buffers.
2922 Either a sample format name or its corresponding integer representation from
2923 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2925 @item channel_layout
2926 The channel layout of the incoming audio buffers.
2927 Either a channel layout name from channel_layout_map in
2928 @file{libavutil/channel_layout.c} or its corresponding integer representation
2929 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2932 The number of channels of the incoming audio buffers.
2933 If both @var{channels} and @var{channel_layout} are specified, then they
2938 @subsection Examples
2941 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2944 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2945 Since the sample format with name "s16p" corresponds to the number
2946 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2949 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2954 Generate an audio signal specified by an expression.
2956 This source accepts in input one or more expressions (one for each
2957 channel), which are evaluated and used to generate a corresponding
2960 This source accepts the following options:
2964 Set the '|'-separated expressions list for each separate channel. In case the
2965 @option{channel_layout} option is not specified, the selected channel layout
2966 depends on the number of provided expressions. Otherwise the last
2967 specified expression is applied to the remaining output channels.
2969 @item channel_layout, c
2970 Set the channel layout. The number of channels in the specified layout
2971 must be equal to the number of specified expressions.
2974 Set the minimum duration of the sourced audio. See
2975 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2976 for the accepted syntax.
2977 Note that the resulting duration may be greater than the specified
2978 duration, as the generated audio is always cut at the end of a
2981 If not specified, or the expressed duration is negative, the audio is
2982 supposed to be generated forever.
2985 Set the number of samples per channel per each output frame,
2988 @item sample_rate, s
2989 Specify the sample rate, default to 44100.
2992 Each expression in @var{exprs} can contain the following constants:
2996 number of the evaluated sample, starting from 0
2999 time of the evaluated sample expressed in seconds, starting from 0
3006 @subsection Examples
3016 Generate a sin signal with frequency of 440 Hz, set sample rate to
3019 aevalsrc="sin(440*2*PI*t):s=8000"
3023 Generate a two channels signal, specify the channel layout (Front
3024 Center + Back Center) explicitly:
3026 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
3030 Generate white noise:
3032 aevalsrc="-2+random(0)"
3036 Generate an amplitude modulated signal:
3038 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
3042 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
3044 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
3051 The null audio source, return unprocessed audio frames. It is mainly useful
3052 as a template and to be employed in analysis / debugging tools, or as
3053 the source for filters which ignore the input data (for example the sox
3056 This source accepts the following options:
3060 @item channel_layout, cl
3062 Specifies the channel layout, and can be either an integer or a string
3063 representing a channel layout. The default value of @var{channel_layout}
3066 Check the channel_layout_map definition in
3067 @file{libavutil/channel_layout.c} for the mapping between strings and
3068 channel layout values.
3070 @item sample_rate, r
3071 Specifies the sample rate, and defaults to 44100.
3074 Set the number of samples per requested frames.
3078 @subsection Examples
3082 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
3084 anullsrc=r=48000:cl=4
3088 Do the same operation with a more obvious syntax:
3090 anullsrc=r=48000:cl=mono
3094 All the parameters need to be explicitly defined.
3098 Synthesize a voice utterance using the libflite library.
3100 To enable compilation of this filter you need to configure FFmpeg with
3101 @code{--enable-libflite}.
3103 Note that the flite library is not thread-safe.
3105 The filter accepts the following options:
3110 If set to 1, list the names of the available voices and exit
3111 immediately. Default value is 0.
3114 Set the maximum number of samples per frame. Default value is 512.
3117 Set the filename containing the text to speak.
3120 Set the text to speak.
3123 Set the voice to use for the speech synthesis. Default value is
3124 @code{kal}. See also the @var{list_voices} option.
3127 @subsection Examples
3131 Read from file @file{speech.txt}, and synthesize the text using the
3132 standard flite voice:
3134 flite=textfile=speech.txt
3138 Read the specified text selecting the @code{slt} voice:
3140 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3144 Input text to ffmpeg:
3146 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3150 Make @file{ffplay} speak the specified text, using @code{flite} and
3151 the @code{lavfi} device:
3153 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
3157 For more information about libflite, check:
3158 @url{http://www.speech.cs.cmu.edu/flite/}
3162 Generate a noise audio signal.
3164 The filter accepts the following options:
3167 @item sample_rate, r
3168 Specify the sample rate. Default value is 48000 Hz.
3171 Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value
3175 Specify the duration of the generated audio stream. Not specifying this option
3176 results in noise with an infinite length.
3178 @item color, colour, c
3179 Specify the color of noise. Available noise colors are white, pink, and brown.
3180 Default color is white.
3183 Specify a value used to seed the PRNG.
3186 Set the number of samples per each output frame, default is 1024.
3189 @subsection Examples
3194 Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of 0.5:
3196 anoisesrc=d=60:c=pink:r=44100:a=0.5
3202 Generate an audio signal made of a sine wave with amplitude 1/8.
3204 The audio signal is bit-exact.
3206 The filter accepts the following options:
3211 Set the carrier frequency. Default is 440 Hz.
3213 @item beep_factor, b
3214 Enable a periodic beep every second with frequency @var{beep_factor} times
3215 the carrier frequency. Default is 0, meaning the beep is disabled.
3217 @item sample_rate, r
3218 Specify the sample rate, default is 44100.
3221 Specify the duration of the generated audio stream.
3223 @item samples_per_frame
3224 Set the number of samples per output frame.
3226 The expression can contain the following constants:
3230 The (sequential) number of the output audio frame, starting from 0.
3233 The PTS (Presentation TimeStamp) of the output audio frame,
3234 expressed in @var{TB} units.
3237 The PTS of the output audio frame, expressed in seconds.
3240 The timebase of the output audio frames.
3243 Default is @code{1024}.
3246 @subsection Examples
3251 Generate a simple 440 Hz sine wave:
3257 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
3261 sine=frequency=220:beep_factor=4:duration=5
3265 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
3268 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
3272 @c man end AUDIO SOURCES
3274 @chapter Audio Sinks
3275 @c man begin AUDIO SINKS
3277 Below is a description of the currently available audio sinks.
3279 @section abuffersink
3281 Buffer audio frames, and make them available to the end of filter chain.
3283 This sink is mainly intended for programmatic use, in particular
3284 through the interface defined in @file{libavfilter/buffersink.h}
3285 or the options system.
3287 It accepts a pointer to an AVABufferSinkContext structure, which
3288 defines the incoming buffers' formats, to be passed as the opaque
3289 parameter to @code{avfilter_init_filter} for initialization.
3292 Null audio sink; do absolutely nothing with the input audio. It is
3293 mainly useful as a template and for use in analysis / debugging
3296 @c man end AUDIO SINKS
3298 @chapter Video Filters
3299 @c man begin VIDEO FILTERS
3301 When you configure your FFmpeg build, you can disable any of the
3302 existing filters using @code{--disable-filters}.
3303 The configure output will show the video filters included in your
3306 Below is a description of the currently available video filters.
3308 @section alphaextract
3310 Extract the alpha component from the input as a grayscale video. This
3311 is especially useful with the @var{alphamerge} filter.
3315 Add or replace the alpha component of the primary input with the
3316 grayscale value of a second input. This is intended for use with
3317 @var{alphaextract} to allow the transmission or storage of frame
3318 sequences that have alpha in a format that doesn't support an alpha
3321 For example, to reconstruct full frames from a normal YUV-encoded video
3322 and a separate video created with @var{alphaextract}, you might use:
3324 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
3327 Since this filter is designed for reconstruction, it operates on frame
3328 sequences without considering timestamps, and terminates when either
3329 input reaches end of stream. This will cause problems if your encoding
3330 pipeline drops frames. If you're trying to apply an image as an
3331 overlay to a video stream, consider the @var{overlay} filter instead.
3335 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
3336 and libavformat to work. On the other hand, it is limited to ASS (Advanced
3337 Substation Alpha) subtitles files.
3339 This filter accepts the following option in addition to the common options from
3340 the @ref{subtitles} filter:
3344 Set the shaping engine
3346 Available values are:
3349 The default libass shaping engine, which is the best available.
3351 Fast, font-agnostic shaper that can do only substitutions
3353 Slower shaper using OpenType for substitutions and positioning
3356 The default is @code{auto}.
3360 Apply an Adaptive Temporal Averaging Denoiser to the video input.
3362 The filter accepts the following options:
3366 Set threshold A for 1st plane. Default is 0.02.
3367 Valid range is 0 to 0.3.
3370 Set threshold B for 1st plane. Default is 0.04.
3371 Valid range is 0 to 5.
3374 Set threshold A for 2nd plane. Default is 0.02.
3375 Valid range is 0 to 0.3.
3378 Set threshold B for 2nd plane. Default is 0.04.
3379 Valid range is 0 to 5.
3382 Set threshold A for 3rd plane. Default is 0.02.
3383 Valid range is 0 to 0.3.
3386 Set threshold B for 3rd plane. Default is 0.04.
3387 Valid range is 0 to 5.
3389 Threshold A is designed to react on abrupt changes in the input signal and
3390 threshold B is designed to react on continuous changes in the input signal.
3393 Set number of frames filter will use for averaging. Default is 33. Must be odd
3394 number in range [5, 129].
3399 Compute the bounding box for the non-black pixels in the input frame
3402 This filter computes the bounding box containing all the pixels with a
3403 luminance value greater than the minimum allowed value.
3404 The parameters describing the bounding box are printed on the filter
3407 The filter accepts the following option:
3411 Set the minimal luminance value. Default is @code{16}.
3414 @section blackdetect
3416 Detect video intervals that are (almost) completely black. Can be
3417 useful to detect chapter transitions, commercials, or invalid
3418 recordings. Output lines contains the time for the start, end and
3419 duration of the detected black interval expressed in seconds.
3421 In order to display the output lines, you need to set the loglevel at
3422 least to the AV_LOG_INFO value.
3424 The filter accepts the following options:
3427 @item black_min_duration, d
3428 Set the minimum detected black duration expressed in seconds. It must
3429 be a non-negative floating point number.
3431 Default value is 2.0.
3433 @item picture_black_ratio_th, pic_th
3434 Set the threshold for considering a picture "black".
3435 Express the minimum value for the ratio:
3437 @var{nb_black_pixels} / @var{nb_pixels}
3440 for which a picture is considered black.
3441 Default value is 0.98.
3443 @item pixel_black_th, pix_th
3444 Set the threshold for considering a pixel "black".
3446 The threshold expresses the maximum pixel luminance value for which a
3447 pixel is considered "black". The provided value is scaled according to
3448 the following equation:
3450 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
3453 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
3454 the input video format, the range is [0-255] for YUV full-range
3455 formats and [16-235] for YUV non full-range formats.
3457 Default value is 0.10.
3460 The following example sets the maximum pixel threshold to the minimum
3461 value, and detects only black intervals of 2 or more seconds:
3463 blackdetect=d=2:pix_th=0.00
3468 Detect frames that are (almost) completely black. Can be useful to
3469 detect chapter transitions or commercials. Output lines consist of
3470 the frame number of the detected frame, the percentage of blackness,
3471 the position in the file if known or -1 and the timestamp in seconds.
3473 In order to display the output lines, you need to set the loglevel at
3474 least to the AV_LOG_INFO value.
3476 It accepts the following parameters:
3481 The percentage of the pixels that have to be below the threshold; it defaults to
3484 @item threshold, thresh
3485 The threshold below which a pixel value is considered black; it defaults to
3490 @section blend, tblend
3492 Blend two video frames into each other.
3494 The @code{blend} filter takes two input streams and outputs one
3495 stream, the first input is the "top" layer and second input is
3496 "bottom" layer. Output terminates when shortest input terminates.
3498 The @code{tblend} (time blend) filter takes two consecutive frames
3499 from one single stream, and outputs the result obtained by blending
3500 the new frame on top of the old frame.
3502 A description of the accepted options follows.
3510 Set blend mode for specific pixel component or all pixel components in case
3511 of @var{all_mode}. Default value is @code{normal}.
3513 Available values for component modes are:
3551 Set blend opacity for specific pixel component or all pixel components in case
3552 of @var{all_opacity}. Only used in combination with pixel component blend modes.
3559 Set blend expression for specific pixel component or all pixel components in case
3560 of @var{all_expr}. Note that related mode options will be ignored if those are set.
3562 The expressions can use the following variables:
3566 The sequential number of the filtered frame, starting from @code{0}.
3570 the coordinates of the current sample
3574 the width and height of currently filtered plane
3578 Width and height scale depending on the currently filtered plane. It is the
3579 ratio between the corresponding luma plane number of pixels and the current
3580 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
3581 @code{0.5,0.5} for chroma planes.
3584 Time of the current frame, expressed in seconds.
3587 Value of pixel component at current location for first video frame (top layer).
3590 Value of pixel component at current location for second video frame (bottom layer).
3594 Force termination when the shortest input terminates. Default is
3595 @code{0}. This option is only defined for the @code{blend} filter.
3598 Continue applying the last bottom frame after the end of the stream. A value of
3599 @code{0} disable the filter after the last frame of the bottom layer is reached.
3600 Default is @code{1}. This option is only defined for the @code{blend} filter.
3603 @subsection Examples
3607 Apply transition from bottom layer to top layer in first 10 seconds:
3609 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
3613 Apply 1x1 checkerboard effect:
3615 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
3619 Apply uncover left effect:
3621 blend=all_expr='if(gte(N*SW+X,W),A,B)'
3625 Apply uncover down effect:
3627 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
3631 Apply uncover up-left effect:
3633 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
3637 Display differences between the current and the previous frame:
3639 tblend=all_mode=difference128
3645 Apply a boxblur algorithm to the input video.
3647 It accepts the following parameters:
3651 @item luma_radius, lr
3652 @item luma_power, lp
3653 @item chroma_radius, cr
3654 @item chroma_power, cp
3655 @item alpha_radius, ar
3656 @item alpha_power, ap
3660 A description of the accepted options follows.
3663 @item luma_radius, lr
3664 @item chroma_radius, cr
3665 @item alpha_radius, ar
3666 Set an expression for the box radius in pixels used for blurring the
3667 corresponding input plane.
3669 The radius value must be a non-negative number, and must not be
3670 greater than the value of the expression @code{min(w,h)/2} for the
3671 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
3674 Default value for @option{luma_radius} is "2". If not specified,
3675 @option{chroma_radius} and @option{alpha_radius} default to the
3676 corresponding value set for @option{luma_radius}.
3678 The expressions can contain the following constants:
3682 The input width and height in pixels.
3686 The input chroma image width and height in pixels.
3690 The horizontal and vertical chroma subsample values. For example, for the
3691 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
3694 @item luma_power, lp
3695 @item chroma_power, cp
3696 @item alpha_power, ap
3697 Specify how many times the boxblur filter is applied to the
3698 corresponding plane.
3700 Default value for @option{luma_power} is 2. If not specified,
3701 @option{chroma_power} and @option{alpha_power} default to the
3702 corresponding value set for @option{luma_power}.
3704 A value of 0 will disable the effect.
3707 @subsection Examples
3711 Apply a boxblur filter with the luma, chroma, and alpha radii
3714 boxblur=luma_radius=2:luma_power=1
3719 Set the luma radius to 2, and alpha and chroma radius to 0:
3721 boxblur=2:1:cr=0:ar=0
3725 Set the luma and chroma radii to a fraction of the video dimension:
3727 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
3732 YUV colorspace color/chroma keying.
3734 The filter accepts the following options:
3738 The color which will be replaced with transparency.
3741 Similarity percentage with the key color.
3743 0.01 matches only the exact key color, while 1.0 matches everything.
3748 0.0 makes pixels either fully transparent, or not transparent at all.
3750 Higher values result in semi-transparent pixels, with a higher transparency
3751 the more similar the pixels color is to the key color.
3754 Signals that the color passed is already in YUV instead of RGB.
3756 Litteral colors like "green" or "red" don't make sense with this enabled anymore.
3757 This can be used to pass exact YUV values as hexadecimal numbers.
3760 @subsection Examples
3764 Make every green pixel in the input image transparent:
3766 ffmpeg -i input.png -vf chromakey=green out.png
3770 Overlay a greenscreen-video on top of a static black background.
3772 ffmpeg -f lavfi -i color=c=black:s=1280x720 -i video.mp4 -shortest -filter_complex "[1:v]chromakey=0x70de77:0.1:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.mkv
3778 Visualize information exported by some codecs.
3780 Some codecs can export information through frames using side-data or other
3781 means. For example, some MPEG based codecs export motion vectors through the
3782 @var{export_mvs} flag in the codec @option{flags2} option.
3784 The filter accepts the following option:
3788 Set motion vectors to visualize.
3790 Available flags for @var{mv} are:
3794 forward predicted MVs of P-frames
3796 forward predicted MVs of B-frames
3798 backward predicted MVs of B-frames
3802 @subsection Examples
3806 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
3808 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
3812 @section colorbalance
3813 Modify intensity of primary colors (red, green and blue) of input frames.
3815 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
3816 regions for the red-cyan, green-magenta or blue-yellow balance.
3818 A positive adjustment value shifts the balance towards the primary color, a negative
3819 value towards the complementary color.
3821 The filter accepts the following options:
3827 Adjust red, green and blue shadows (darkest pixels).
3832 Adjust red, green and blue midtones (medium pixels).
3837 Adjust red, green and blue highlights (brightest pixels).
3839 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3842 @subsection Examples
3846 Add red color cast to shadows:
3853 RGB colorspace color keying.
3855 The filter accepts the following options:
3859 The color which will be replaced with transparency.
3862 Similarity percentage with the key color.
3864 0.01 matches only the exact key color, while 1.0 matches everything.
3869 0.0 makes pixels either fully transparent, or not transparent at all.
3871 Higher values result in semi-transparent pixels, with a higher transparency
3872 the more similar the pixels color is to the key color.
3875 @subsection Examples
3879 Make every green pixel in the input image transparent:
3881 ffmpeg -i input.png -vf colorkey=green out.png
3885 Overlay a greenscreen-video on top of a static background image.
3887 ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv
3891 @section colorlevels
3893 Adjust video input frames using levels.
3895 The filter accepts the following options:
3902 Adjust red, green, blue and alpha input black point.
3903 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3909 Adjust red, green, blue and alpha input white point.
3910 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
3912 Input levels are used to lighten highlights (bright tones), darken shadows
3913 (dark tones), change the balance of bright and dark tones.
3919 Adjust red, green, blue and alpha output black point.
3920 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
3926 Adjust red, green, blue and alpha output white point.
3927 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
3929 Output levels allows manual selection of a constrained output level range.
3932 @subsection Examples
3936 Make video output darker:
3938 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3944 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3948 Make video output lighter:
3950 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3954 Increase brightness:
3956 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3960 @section colorchannelmixer
3962 Adjust video input frames by re-mixing color channels.
3964 This filter modifies a color channel by adding the values associated to
3965 the other channels of the same pixels. For example if the value to
3966 modify is red, the output value will be:
3968 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3971 The filter accepts the following options:
3978 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3979 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3985 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3986 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3992 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3993 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3999 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
4000 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
4002 Allowed ranges for options are @code{[-2.0, 2.0]}.
4005 @subsection Examples
4009 Convert source to grayscale:
4011 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
4014 Simulate sepia tones:
4016 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
4020 @section colormatrix
4022 Convert color matrix.
4024 The filter accepts the following options:
4029 Specify the source and destination color matrix. Both values must be
4032 The accepted values are:
4048 For example to convert from BT.601 to SMPTE-240M, use the command:
4050 colormatrix=bt601:smpte240m
4055 Copy the input source unchanged to the output. This is mainly useful for
4060 Crop the input video to given dimensions.
4062 It accepts the following parameters:
4066 The width of the output video. It defaults to @code{iw}.
4067 This expression is evaluated only once during the filter
4068 configuration, or when the @samp{w} or @samp{out_w} command is sent.
4071 The height of the output video. It defaults to @code{ih}.
4072 This expression is evaluated only once during the filter
4073 configuration, or when the @samp{h} or @samp{out_h} command is sent.
4076 The horizontal position, in the input video, of the left edge of the output
4077 video. It defaults to @code{(in_w-out_w)/2}.
4078 This expression is evaluated per-frame.
4081 The vertical position, in the input video, of the top edge of the output video.
4082 It defaults to @code{(in_h-out_h)/2}.
4083 This expression is evaluated per-frame.
4086 If set to 1 will force the output display aspect ratio
4087 to be the same of the input, by changing the output sample aspect
4088 ratio. It defaults to 0.
4091 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
4092 expressions containing the following constants:
4097 The computed values for @var{x} and @var{y}. They are evaluated for
4102 The input width and height.
4106 These are the same as @var{in_w} and @var{in_h}.
4110 The output (cropped) width and height.
4114 These are the same as @var{out_w} and @var{out_h}.
4117 same as @var{iw} / @var{ih}
4120 input sample aspect ratio
4123 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
4127 horizontal and vertical chroma subsample values. For example for the
4128 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4131 The number of the input frame, starting from 0.
4134 the position in the file of the input frame, NAN if unknown
4137 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
4141 The expression for @var{out_w} may depend on the value of @var{out_h},
4142 and the expression for @var{out_h} may depend on @var{out_w}, but they
4143 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
4144 evaluated after @var{out_w} and @var{out_h}.
4146 The @var{x} and @var{y} parameters specify the expressions for the
4147 position of the top-left corner of the output (non-cropped) area. They
4148 are evaluated for each frame. If the evaluated value is not valid, it
4149 is approximated to the nearest valid value.
4151 The expression for @var{x} may depend on @var{y}, and the expression
4152 for @var{y} may depend on @var{x}.
4154 @subsection Examples
4158 Crop area with size 100x100 at position (12,34).
4163 Using named options, the example above becomes:
4165 crop=w=100:h=100:x=12:y=34
4169 Crop the central input area with size 100x100:
4175 Crop the central input area with size 2/3 of the input video:
4177 crop=2/3*in_w:2/3*in_h
4181 Crop the input video central square:
4188 Delimit the rectangle with the top-left corner placed at position
4189 100:100 and the right-bottom corner corresponding to the right-bottom
4190 corner of the input image.
4192 crop=in_w-100:in_h-100:100:100
4196 Crop 10 pixels from the left and right borders, and 20 pixels from
4197 the top and bottom borders
4199 crop=in_w-2*10:in_h-2*20
4203 Keep only the bottom right quarter of the input image:
4205 crop=in_w/2:in_h/2:in_w/2:in_h/2
4209 Crop height for getting Greek harmony:
4211 crop=in_w:1/PHI*in_w
4215 Apply trembling effect:
4217 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)
4221 Apply erratic camera effect depending on timestamp:
4223 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)"
4227 Set x depending on the value of y:
4229 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
4233 @subsection Commands
4235 This filter supports the following commands:
4241 Set width/height of the output video and the horizontal/vertical position
4243 The command accepts the same syntax of the corresponding option.
4245 If the specified expression is not valid, it is kept at its current
4251 Auto-detect the crop size.
4253 It calculates the necessary cropping parameters and prints the
4254 recommended parameters via the logging system. The detected dimensions
4255 correspond to the non-black area of the input video.
4257 It accepts the following parameters:
4262 Set higher black value threshold, which can be optionally specified
4263 from nothing (0) to everything (255 for 8bit based formats). An intensity
4264 value greater to the set value is considered non-black. It defaults to 24.
4265 You can also specify a value between 0.0 and 1.0 which will be scaled depending
4266 on the bitdepth of the pixel format.
4269 The value which the width/height should be divisible by. It defaults to
4270 16. The offset is automatically adjusted to center the video. Use 2 to
4271 get only even dimensions (needed for 4:2:2 video). 16 is best when
4272 encoding to most video codecs.
4274 @item reset_count, reset
4275 Set the counter that determines after how many frames cropdetect will
4276 reset the previously detected largest video area and start over to
4277 detect the current optimal crop area. Default value is 0.
4279 This can be useful when channel logos distort the video area. 0
4280 indicates 'never reset', and returns the largest area encountered during
4287 Apply color adjustments using curves.
4289 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
4290 component (red, green and blue) has its values defined by @var{N} key points
4291 tied from each other using a smooth curve. The x-axis represents the pixel
4292 values from the input frame, and the y-axis the new pixel values to be set for
4295 By default, a component curve is defined by the two points @var{(0;0)} and
4296 @var{(1;1)}. This creates a straight line where each original pixel value is
4297 "adjusted" to its own value, which means no change to the image.
4299 The filter allows you to redefine these two points and add some more. A new
4300 curve (using a natural cubic spline interpolation) will be define to pass
4301 smoothly through all these new coordinates. The new defined points needs to be
4302 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
4303 be in the @var{[0;1]} interval. If the computed curves happened to go outside
4304 the vector spaces, the values will be clipped accordingly.
4306 If there is no key point defined in @code{x=0}, the filter will automatically
4307 insert a @var{(0;0)} point. In the same way, if there is no key point defined
4308 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
4310 The filter accepts the following options:
4314 Select one of the available color presets. This option can be used in addition
4315 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
4316 options takes priority on the preset values.
4317 Available presets are:
4320 @item color_negative
4323 @item increase_contrast
4325 @item linear_contrast
4326 @item medium_contrast
4328 @item strong_contrast
4331 Default is @code{none}.
4333 Set the master key points. These points will define a second pass mapping. It
4334 is sometimes called a "luminance" or "value" mapping. It can be used with
4335 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
4336 post-processing LUT.
4338 Set the key points for the red component.
4340 Set the key points for the green component.
4342 Set the key points for the blue component.
4344 Set the key points for all components (not including master).
4345 Can be used in addition to the other key points component
4346 options. In this case, the unset component(s) will fallback on this
4347 @option{all} setting.
4349 Specify a Photoshop curves file (@code{.acv}) to import the settings from.
4352 To avoid some filtergraph syntax conflicts, each key points list need to be
4353 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
4355 @subsection Examples
4359 Increase slightly the middle level of blue:
4361 curves=blue='0.5/0.58'
4367 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
4369 Here we obtain the following coordinates for each components:
4372 @code{(0;0.11) (0.42;0.51) (1;0.95)}
4374 @code{(0;0) (0.50;0.48) (1;1)}
4376 @code{(0;0.22) (0.49;0.44) (1;0.80)}
4380 The previous example can also be achieved with the associated built-in preset:
4382 curves=preset=vintage
4392 Use a Photoshop preset and redefine the points of the green component:
4394 curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
4400 Denoise frames using 2D DCT (frequency domain filtering).
4402 This filter is not designed for real time.
4404 The filter accepts the following options:
4408 Set the noise sigma constant.
4410 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
4411 coefficient (absolute value) below this threshold with be dropped.
4413 If you need a more advanced filtering, see @option{expr}.
4415 Default is @code{0}.
4418 Set number overlapping pixels for each block. Since the filter can be slow, you
4419 may want to reduce this value, at the cost of a less effective filter and the
4420 risk of various artefacts.
4422 If the overlapping value doesn't permit processing the whole input width or
4423 height, a warning will be displayed and according borders won't be denoised.
4425 Default value is @var{blocksize}-1, which is the best possible setting.
4428 Set the coefficient factor expression.
4430 For each coefficient of a DCT block, this expression will be evaluated as a
4431 multiplier value for the coefficient.
4433 If this is option is set, the @option{sigma} option will be ignored.
4435 The absolute value of the coefficient can be accessed through the @var{c}
4439 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
4440 @var{blocksize}, which is the width and height of the processed blocks.
4442 The default value is @var{3} (8x8) and can be raised to @var{4} for a
4443 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
4444 on the speed processing. Also, a larger block size does not necessarily means a
4448 @subsection Examples
4450 Apply a denoise with a @option{sigma} of @code{4.5}:
4455 The same operation can be achieved using the expression system:
4457 dctdnoiz=e='gte(c, 4.5*3)'
4460 Violent denoise using a block size of @code{16x16}:
4467 Remove banding artifacts from input video.
4468 It works by replacing banded pixels with average value of referenced pixels.
4470 The filter accepts the following options:
4477 Set banding detection threshold for each plane. Default is 0.02.
4478 Valid range is 0.00003 to 0.5.
4479 If difference between current pixel and reference pixel is less than threshold,
4480 it will be considered as banded.
4483 Banding detection range in pixels. Default is 16. If positive, random number
4484 in range 0 to set value will be used. If negative, exact absolute value
4486 The range defines square of four pixels around current pixel.
4489 Set direction in radians from which four pixel will be compared. If positive,
4490 random direction from 0 to set direction will be picked. If negative, exact of
4491 absolute value will be picked. For example direction 0, -PI or -2*PI radians
4492 will pick only pixels on same row and -PI/2 will pick only pixels on same
4496 If enabled, current pixel is compared with average value of all four
4497 surrounding pixels. The default is enabled. If disabled current pixel is
4498 compared with all four surrounding pixels. The pixel is considered banded
4499 if only all four differences with surrounding pixels are less than threshold.
4505 Drop duplicated frames at regular intervals.
4507 The filter accepts the following options:
4511 Set the number of frames from which one will be dropped. Setting this to
4512 @var{N} means one frame in every batch of @var{N} frames will be dropped.
4513 Default is @code{5}.
4516 Set the threshold for duplicate detection. If the difference metric for a frame
4517 is less than or equal to this value, then it is declared as duplicate. Default
4521 Set scene change threshold. Default is @code{15}.
4525 Set the size of the x and y-axis blocks used during metric calculations.
4526 Larger blocks give better noise suppression, but also give worse detection of
4527 small movements. Must be a power of two. Default is @code{32}.
4530 Mark main input as a pre-processed input and activate clean source input
4531 stream. This allows the input to be pre-processed with various filters to help
4532 the metrics calculation while keeping the frame selection lossless. When set to
4533 @code{1}, the first stream is for the pre-processed input, and the second
4534 stream is the clean source from where the kept frames are chosen. Default is
4538 Set whether or not chroma is considered in the metric calculations. Default is
4544 Apply deflate effect to the video.
4546 This filter replaces the pixel by the local(3x3) average by taking into account
4547 only values lower than the pixel.
4549 It accepts the following options:
4556 Limit the maximum change for each plane, default is 65535.
4557 If 0, plane will remain unchanged.
4562 Remove judder produced by partially interlaced telecined content.
4564 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
4565 source was partially telecined content then the output of @code{pullup,dejudder}
4566 will have a variable frame rate. May change the recorded frame rate of the
4567 container. Aside from that change, this filter will not affect constant frame
4570 The option available in this filter is:
4574 Specify the length of the window over which the judder repeats.
4576 Accepts any integer greater than 1. Useful values are:
4580 If the original was telecined from 24 to 30 fps (Film to NTSC).
4583 If the original was telecined from 25 to 30 fps (PAL to NTSC).
4586 If a mixture of the two.
4589 The default is @samp{4}.
4594 Suppress a TV station logo by a simple interpolation of the surrounding
4595 pixels. Just set a rectangle covering the logo and watch it disappear
4596 (and sometimes something even uglier appear - your mileage may vary).
4598 It accepts the following parameters:
4603 Specify the top left corner coordinates of the logo. They must be
4608 Specify the width and height of the logo to clear. They must be
4612 Specify the thickness of the fuzzy edge of the rectangle (added to
4613 @var{w} and @var{h}). The default value is 1. This option is
4614 deprecated, setting higher values should no longer be necessary and
4618 When set to 1, a green rectangle is drawn on the screen to simplify
4619 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
4620 The default value is 0.
4622 The rectangle is drawn on the outermost pixels which will be (partly)
4623 replaced with interpolated values. The values of the next pixels
4624 immediately outside this rectangle in each direction will be used to
4625 compute the interpolated pixel values inside the rectangle.
4629 @subsection Examples
4633 Set a rectangle covering the area with top left corner coordinates 0,0
4634 and size 100x77, and a band of size 10:
4636 delogo=x=0:y=0:w=100:h=77:band=10
4643 Attempt to fix small changes in horizontal and/or vertical shift. This
4644 filter helps remove camera shake from hand-holding a camera, bumping a
4645 tripod, moving on a vehicle, etc.
4647 The filter accepts the following options:
4655 Specify a rectangular area where to limit the search for motion
4657 If desired the search for motion vectors can be limited to a
4658 rectangular area of the frame defined by its top left corner, width
4659 and height. These parameters have the same meaning as the drawbox
4660 filter which can be used to visualise the position of the bounding
4663 This is useful when simultaneous movement of subjects within the frame
4664 might be confused for camera motion by the motion vector search.
4666 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
4667 then the full frame is used. This allows later options to be set
4668 without specifying the bounding box for the motion vector search.
4670 Default - search the whole frame.
4674 Specify the maximum extent of movement in x and y directions in the
4675 range 0-64 pixels. Default 16.
4678 Specify how to generate pixels to fill blanks at the edge of the
4679 frame. Available values are:
4682 Fill zeroes at blank locations
4684 Original image at blank locations
4686 Extruded edge value at blank locations
4688 Mirrored edge at blank locations
4690 Default value is @samp{mirror}.
4693 Specify the blocksize to use for motion search. Range 4-128 pixels,
4697 Specify the contrast threshold for blocks. Only blocks with more than
4698 the specified contrast (difference between darkest and lightest
4699 pixels) will be considered. Range 1-255, default 125.
4702 Specify the search strategy. Available values are:
4705 Set exhaustive search
4707 Set less exhaustive search.
4709 Default value is @samp{exhaustive}.
4712 If set then a detailed log of the motion search is written to the
4716 If set to 1, specify using OpenCL capabilities, only available if
4717 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
4723 Apply an exact inverse of the telecine operation. It requires a predefined
4724 pattern specified using the pattern option which must be the same as that passed
4725 to the telecine filter.
4727 This filter accepts the following options:
4736 The default value is @code{top}.
4740 A string of numbers representing the pulldown pattern you wish to apply.
4741 The default value is @code{23}.
4744 A number representing position of the first frame with respect to the telecine
4745 pattern. This is to be used if the stream is cut. The default value is @code{0}.
4750 Apply dilation effect to the video.
4752 This filter replaces the pixel by the local(3x3) maximum.
4754 It accepts the following options:
4761 Limit the maximum change for each plane, default is 65535.
4762 If 0, plane will remain unchanged.
4765 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
4768 Flags to local 3x3 coordinates maps like this:
4777 Displace pixels as indicated by second and third input stream.
4779 It takes three input streams and outputs one stream, the first input is the
4780 source, and second and third input are displacement maps.
4782 The second input specifies how much to displace pixels along the
4783 x-axis, while the third input specifies how much to displace pixels
4785 If one of displacement map streams terminates, last frame from that
4786 displacement map will be used.
4788 Note that once generated, displacements maps can be reused over and over again.
4790 A description of the accepted options follows.
4794 Set displace behavior for pixels that are out of range.
4796 Available values are:
4799 Missing pixels are replaced by black pixels.
4802 Adjacent pixels will spread out to replace missing pixels.
4805 Out of range pixels are wrapped so they point to pixels of other side.
4807 Default is @samp{smear}.
4811 @subsection Examples
4815 Add ripple effect to rgb input of video size hd720:
4817 ffmpeg -i INPUT -f lavfi -i nullsrc=s=hd720,lutrgb=128:128:128 -f lavfi -i nullsrc=s=hd720,geq='r=128+30*sin(2*PI*X/400+T):g=128+30*sin(2*PI*X/400+T):b=128+30*sin(2*PI*X/400+T)' -lavfi '[0][1][2]displace' OUTPUT
4821 Add wave effect to rgb input of video size hd720:
4823 ffmpeg -i INPUT -f lavfi -i nullsrc=hd720,geq='r=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):g=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):b=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T))' -lavfi '[1]split[x][y],[0][x][y]displace' OUTPUT
4829 Draw a colored box on the input image.
4831 It accepts the following parameters:
4836 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
4840 The expressions which specify the width and height of the box; if 0 they are interpreted as
4841 the input width and height. It defaults to 0.
4844 Specify the color of the box to write. For the general syntax of this option,
4845 check the "Color" section in the ffmpeg-utils manual. If the special
4846 value @code{invert} is used, the box edge color is the same as the
4847 video with inverted luma.
4850 The expression which sets the thickness of the box edge. Default value is @code{3}.
4852 See below for the list of accepted constants.
4855 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
4856 following constants:
4860 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
4864 horizontal and vertical chroma subsample values. For example for the
4865 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4869 The input width and height.
4872 The input sample aspect ratio.
4876 The x and y offset coordinates where the box is drawn.
4880 The width and height of the drawn box.
4883 The thickness of the drawn box.
4885 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
4886 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
4890 @subsection Examples
4894 Draw a black box around the edge of the input image:
4900 Draw a box with color red and an opacity of 50%:
4902 drawbox=10:20:200:60:red@@0.5
4905 The previous example can be specified as:
4907 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
4911 Fill the box with pink color:
4913 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
4917 Draw a 2-pixel red 2.40:1 mask:
4919 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
4923 @section drawgraph, adrawgraph
4925 Draw a graph using input video or audio metadata.
4927 It accepts the following parameters:
4931 Set 1st frame metadata key from which metadata values will be used to draw a graph.
4934 Set 1st foreground color expression.
4937 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
4940 Set 2nd foreground color expression.
4943 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
4946 Set 3rd foreground color expression.
4949 Set 4th frame metadata key from which metadata values will be used to draw a graph.
4952 Set 4th foreground color expression.
4955 Set minimal value of metadata value.
4958 Set maximal value of metadata value.
4961 Set graph background color. Default is white.
4966 Available values for mode is:
4973 Default is @code{line}.
4978 Available values for slide is:
4981 Draw new frame when right border is reached.
4984 Replace old columns with new ones.
4987 Scroll from right to left.
4990 Scroll from left to right.
4993 Default is @code{frame}.
4996 Set size of graph video. For the syntax of this option, check the
4997 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
4998 The default value is @code{900x256}.
5000 The foreground color expressions can use the following variables:
5003 Minimal value of metadata value.
5006 Maximal value of metadata value.
5009 Current metadata key value.
5012 The color is defined as 0xAABBGGRR.
5015 Example using metadata from @ref{signalstats} filter:
5017 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
5020 Example using metadata from @ref{ebur128} filter:
5022 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
5027 Draw a grid on the input image.
5029 It accepts the following parameters:
5034 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
5038 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
5039 input width and height, respectively, minus @code{thickness}, so image gets
5040 framed. Default to 0.
5043 Specify the color of the grid. For the general syntax of this option,
5044 check the "Color" section in the ffmpeg-utils manual. If the special
5045 value @code{invert} is used, the grid color is the same as the
5046 video with inverted luma.
5049 The expression which sets the thickness of the grid line. Default value is @code{1}.
5051 See below for the list of accepted constants.
5054 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
5055 following constants:
5059 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
5063 horizontal and vertical chroma subsample values. For example for the
5064 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5068 The input grid cell width and height.
5071 The input sample aspect ratio.
5075 The x and y coordinates of some point of grid intersection (meant to configure offset).
5079 The width and height of the drawn cell.
5082 The thickness of the drawn cell.
5084 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
5085 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
5089 @subsection Examples
5093 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
5095 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
5099 Draw a white 3x3 grid with an opacity of 50%:
5101 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
5108 Draw a text string or text from a specified file on top of a video, using the
5109 libfreetype library.
5111 To enable compilation of this filter, you need to configure FFmpeg with
5112 @code{--enable-libfreetype}.
5113 To enable default font fallback and the @var{font} option you need to
5114 configure FFmpeg with @code{--enable-libfontconfig}.
5115 To enable the @var{text_shaping} option, you need to configure FFmpeg with
5116 @code{--enable-libfribidi}.
5120 It accepts the following parameters:
5125 Used to draw a box around text using the background color.
5126 The value must be either 1 (enable) or 0 (disable).
5127 The default value of @var{box} is 0.
5130 Set the width of the border to be drawn around the box using @var{boxcolor}.
5131 The default value of @var{boxborderw} is 0.
5134 The color to be used for drawing box around text. For the syntax of this
5135 option, check the "Color" section in the ffmpeg-utils manual.
5137 The default value of @var{boxcolor} is "white".
5140 Set the width of the border to be drawn around the text using @var{bordercolor}.
5141 The default value of @var{borderw} is 0.
5144 Set the color to be used for drawing border around text. For the syntax of this
5145 option, check the "Color" section in the ffmpeg-utils manual.
5147 The default value of @var{bordercolor} is "black".
5150 Select how the @var{text} is expanded. Can be either @code{none},
5151 @code{strftime} (deprecated) or
5152 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
5156 If true, check and fix text coords to avoid clipping.
5159 The color to be used for drawing fonts. For the syntax of this option, check
5160 the "Color" section in the ffmpeg-utils manual.
5162 The default value of @var{fontcolor} is "black".
5164 @item fontcolor_expr
5165 String which is expanded the same way as @var{text} to obtain dynamic
5166 @var{fontcolor} value. By default this option has empty value and is not
5167 processed. When this option is set, it overrides @var{fontcolor} option.
5170 The font family to be used for drawing text. By default Sans.
5173 The font file to be used for drawing text. The path must be included.
5174 This parameter is mandatory if the fontconfig support is disabled.
5177 This option does not exist, please see the timeline system
5180 Draw the text applying alpha blending. The value can
5181 be either a number between 0.0 and 1.0
5182 The expression accepts the same variables @var{x, y} do.
5183 The default value is 1.
5184 Please see fontcolor_expr
5187 The font size to be used for drawing text.
5188 The default value of @var{fontsize} is 16.
5191 If set to 1, attempt to shape the text (for example, reverse the order of
5192 right-to-left text and join Arabic characters) before drawing it.
5193 Otherwise, just draw the text exactly as given.
5194 By default 1 (if supported).
5197 The flags to be used for loading the fonts.
5199 The flags map the corresponding flags supported by libfreetype, and are
5200 a combination of the following values:
5207 @item vertical_layout
5208 @item force_autohint
5211 @item ignore_global_advance_width
5213 @item ignore_transform
5219 Default value is "default".
5221 For more information consult the documentation for the FT_LOAD_*
5225 The color to be used for drawing a shadow behind the drawn text. For the
5226 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
5228 The default value of @var{shadowcolor} is "black".
5232 The x and y offsets for the text shadow position with respect to the
5233 position of the text. They can be either positive or negative
5234 values. The default value for both is "0".
5237 The starting frame number for the n/frame_num variable. The default value
5241 The size in number of spaces to use for rendering the tab.
5245 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
5246 format. It can be used with or without text parameter. @var{timecode_rate}
5247 option must be specified.
5249 @item timecode_rate, rate, r
5250 Set the timecode frame rate (timecode only).
5253 The text string to be drawn. The text must be a sequence of UTF-8
5255 This parameter is mandatory if no file is specified with the parameter
5259 A text file containing text to be drawn. The text must be a sequence
5260 of UTF-8 encoded characters.
5262 This parameter is mandatory if no text string is specified with the
5263 parameter @var{text}.
5265 If both @var{text} and @var{textfile} are specified, an error is thrown.
5268 If set to 1, the @var{textfile} will be reloaded before each frame.
5269 Be sure to update it atomically, or it may be read partially, or even fail.
5273 The expressions which specify the offsets where text will be drawn
5274 within the video frame. They are relative to the top/left border of the
5277 The default value of @var{x} and @var{y} is "0".
5279 See below for the list of accepted constants and functions.
5282 The parameters for @var{x} and @var{y} are expressions containing the
5283 following constants and functions:
5287 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
5291 horizontal and vertical chroma subsample values. For example for the
5292 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5295 the height of each text line
5303 @item max_glyph_a, ascent
5304 the maximum distance from the baseline to the highest/upper grid
5305 coordinate used to place a glyph outline point, for all the rendered
5307 It is a positive value, due to the grid's orientation with the Y axis
5310 @item max_glyph_d, descent
5311 the maximum distance from the baseline to the lowest grid coordinate
5312 used to place a glyph outline point, for all the rendered glyphs.
5313 This is a negative value, due to the grid's orientation, with the Y axis
5317 maximum glyph height, that is the maximum height for all the glyphs
5318 contained in the rendered text, it is equivalent to @var{ascent} -
5322 maximum glyph width, that is the maximum width for all the glyphs
5323 contained in the rendered text
5326 the number of input frame, starting from 0
5328 @item rand(min, max)
5329 return a random number included between @var{min} and @var{max}
5332 The input sample aspect ratio.
5335 timestamp expressed in seconds, NAN if the input timestamp is unknown
5338 the height of the rendered text
5341 the width of the rendered text
5345 the x and y offset coordinates where the text is drawn.
5347 These parameters allow the @var{x} and @var{y} expressions to refer
5348 each other, so you can for example specify @code{y=x/dar}.
5351 @anchor{drawtext_expansion}
5352 @subsection Text expansion
5354 If @option{expansion} is set to @code{strftime},
5355 the filter recognizes strftime() sequences in the provided text and
5356 expands them accordingly. Check the documentation of strftime(). This
5357 feature is deprecated.
5359 If @option{expansion} is set to @code{none}, the text is printed verbatim.
5361 If @option{expansion} is set to @code{normal} (which is the default),
5362 the following expansion mechanism is used.
5364 The backslash character @samp{\}, followed by any character, always expands to
5365 the second character.
5367 Sequence of the form @code{%@{...@}} are expanded. The text between the
5368 braces is a function name, possibly followed by arguments separated by ':'.
5369 If the arguments contain special characters or delimiters (':' or '@}'),
5370 they should be escaped.
5372 Note that they probably must also be escaped as the value for the
5373 @option{text} option in the filter argument string and as the filter
5374 argument in the filtergraph description, and possibly also for the shell,
5375 that makes up to four levels of escaping; using a text file avoids these
5378 The following functions are available:
5383 The expression evaluation result.
5385 It must take one argument specifying the expression to be evaluated,
5386 which accepts the same constants and functions as the @var{x} and
5387 @var{y} values. Note that not all constants should be used, for
5388 example the text size is not known when evaluating the expression, so
5389 the constants @var{text_w} and @var{text_h} will have an undefined
5392 @item expr_int_format, eif
5393 Evaluate the expression's value and output as formatted integer.
5395 The first argument is the expression to be evaluated, just as for the @var{expr} function.
5396 The second argument specifies the output format. Allowed values are @samp{x},
5397 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
5398 @code{printf} function.
5399 The third parameter is optional and sets the number of positions taken by the output.
5400 It can be used to add padding with zeros from the left.
5403 The time at which the filter is running, expressed in UTC.
5404 It can accept an argument: a strftime() format string.
5407 The time at which the filter is running, expressed in the local time zone.
5408 It can accept an argument: a strftime() format string.
5411 Frame metadata. It must take one argument specifying metadata key.
5414 The frame number, starting from 0.
5417 A 1 character description of the current picture type.
5420 The timestamp of the current frame.
5421 It can take up to three arguments.
5423 The first argument is the format of the timestamp; it defaults to @code{flt}
5424 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
5425 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
5426 @code{gmtime} stands for the timestamp of the frame formatted as UTC time;
5427 @code{localtime} stands for the timestamp of the frame formatted as
5428 local time zone time.
5430 The second argument is an offset added to the timestamp.
5432 If the format is set to @code{localtime} or @code{gmtime},
5433 a third argument may be supplied: a strftime() format string.
5434 By default, @var{YYYY-MM-DD HH:MM:SS} format will be used.
5437 @subsection Examples
5441 Draw "Test Text" with font FreeSerif, using the default values for the
5442 optional parameters.
5445 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
5449 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
5450 and y=50 (counting from the top-left corner of the screen), text is
5451 yellow with a red box around it. Both the text and the box have an
5455 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
5456 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
5459 Note that the double quotes are not necessary if spaces are not used
5460 within the parameter list.
5463 Show the text at the center of the video frame:
5465 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
5469 Show a text line sliding from right to left in the last row of the video
5470 frame. The file @file{LONG_LINE} is assumed to contain a single line
5473 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
5477 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
5479 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
5483 Draw a single green letter "g", at the center of the input video.
5484 The glyph baseline is placed at half screen height.
5486 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
5490 Show text for 1 second every 3 seconds:
5492 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
5496 Use fontconfig to set the font. Note that the colons need to be escaped.
5498 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
5502 Print the date of a real-time encoding (see strftime(3)):
5504 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
5508 Show text fading in and out (appearing/disappearing):
5511 DS=1.0 # display start
5512 DE=10.0 # display end
5513 FID=1.5 # fade in duration
5514 FOD=5 # fade out duration
5515 ffplay -f lavfi "color,drawtext=text=TEST:fontsize=50:fontfile=FreeSerif.ttf:fontcolor_expr=ff0000%@{eif\\\\: clip(255*(1*between(t\\, $DS + $FID\\, $DE - $FOD) + ((t - $DS)/$FID)*between(t\\, $DS\\, $DS + $FID) + (-(t - $DE)/$FOD)*between(t\\, $DE - $FOD\\, $DE) )\\, 0\\, 255) \\\\: x\\\\: 2 @}"
5520 For more information about libfreetype, check:
5521 @url{http://www.freetype.org/}.
5523 For more information about fontconfig, check:
5524 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
5526 For more information about libfribidi, check:
5527 @url{http://fribidi.org/}.
5531 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
5533 The filter accepts the following options:
5538 Set low and high threshold values used by the Canny thresholding
5541 The high threshold selects the "strong" edge pixels, which are then
5542 connected through 8-connectivity with the "weak" edge pixels selected
5543 by the low threshold.
5545 @var{low} and @var{high} threshold values must be chosen in the range
5546 [0,1], and @var{low} should be lesser or equal to @var{high}.
5548 Default value for @var{low} is @code{20/255}, and default value for @var{high}
5552 Define the drawing mode.
5556 Draw white/gray wires on black background.
5559 Mix the colors to create a paint/cartoon effect.
5562 Default value is @var{wires}.
5565 @subsection Examples
5569 Standard edge detection with custom values for the hysteresis thresholding:
5571 edgedetect=low=0.1:high=0.4
5575 Painting effect without thresholding:
5577 edgedetect=mode=colormix:high=0
5582 Set brightness, contrast, saturation and approximate gamma adjustment.
5584 The filter accepts the following options:
5588 Set the contrast expression. The value must be a float value in range
5589 @code{-2.0} to @code{2.0}. The default value is "1".
5592 Set the brightness expression. The value must be a float value in
5593 range @code{-1.0} to @code{1.0}. The default value is "0".
5596 Set the saturation expression. The value must be a float in
5597 range @code{0.0} to @code{3.0}. The default value is "1".
5600 Set the gamma expression. The value must be a float in range
5601 @code{0.1} to @code{10.0}. The default value is "1".
5604 Set the gamma expression for red. The value must be a float in
5605 range @code{0.1} to @code{10.0}. The default value is "1".
5608 Set the gamma expression for green. The value must be a float in range
5609 @code{0.1} to @code{10.0}. The default value is "1".
5612 Set the gamma expression for blue. The value must be a float in range
5613 @code{0.1} to @code{10.0}. The default value is "1".
5616 Set the gamma weight expression. It can be used to reduce the effect
5617 of a high gamma value on bright image areas, e.g. keep them from
5618 getting overamplified and just plain white. The value must be a float
5619 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
5620 gamma correction all the way down while @code{1.0} leaves it at its
5621 full strength. Default is "1".
5624 Set when the expressions for brightness, contrast, saturation and
5625 gamma expressions are evaluated.
5627 It accepts the following values:
5630 only evaluate expressions once during the filter initialization or
5631 when a command is processed
5634 evaluate expressions for each incoming frame
5637 Default value is @samp{init}.
5640 The expressions accept the following parameters:
5643 frame count of the input frame starting from 0
5646 byte position of the corresponding packet in the input file, NAN if
5650 frame rate of the input video, NAN if the input frame rate is unknown
5653 timestamp expressed in seconds, NAN if the input timestamp is unknown
5656 @subsection Commands
5657 The filter supports the following commands:
5661 Set the contrast expression.
5664 Set the brightness expression.
5667 Set the saturation expression.
5670 Set the gamma expression.
5673 Set the gamma_r expression.
5676 Set gamma_g expression.
5679 Set gamma_b expression.
5682 Set gamma_weight expression.
5684 The command accepts the same syntax of the corresponding option.
5686 If the specified expression is not valid, it is kept at its current
5693 Apply erosion effect to the video.
5695 This filter replaces the pixel by the local(3x3) minimum.
5697 It accepts the following options:
5704 Limit the maximum change for each plane, default is 65535.
5705 If 0, plane will remain unchanged.
5708 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
5711 Flags to local 3x3 coordinates maps like this:
5718 @section extractplanes
5720 Extract color channel components from input video stream into
5721 separate grayscale video streams.
5723 The filter accepts the following option:
5727 Set plane(s) to extract.
5729 Available values for planes are:
5740 Choosing planes not available in the input will result in an error.
5741 That means you cannot select @code{r}, @code{g}, @code{b} planes
5742 with @code{y}, @code{u}, @code{v} planes at same time.
5745 @subsection Examples
5749 Extract luma, u and v color channel component from input video frame
5750 into 3 grayscale outputs:
5752 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
5758 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
5760 For each input image, the filter will compute the optimal mapping from
5761 the input to the output given the codebook length, that is the number
5762 of distinct output colors.
5764 This filter accepts the following options.
5767 @item codebook_length, l
5768 Set codebook length. The value must be a positive integer, and
5769 represents the number of distinct output colors. Default value is 256.
5772 Set the maximum number of iterations to apply for computing the optimal
5773 mapping. The higher the value the better the result and the higher the
5774 computation time. Default value is 1.
5777 Set a random seed, must be an integer included between 0 and
5778 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
5779 will try to use a good random seed on a best effort basis.
5782 Set pal8 output pixel format. This option does not work with codebook
5783 length greater than 256.
5788 Apply a fade-in/out effect to the input video.
5790 It accepts the following parameters:
5794 The effect type can be either "in" for a fade-in, or "out" for a fade-out
5796 Default is @code{in}.
5798 @item start_frame, s
5799 Specify the number of the frame to start applying the fade
5800 effect at. Default is 0.
5803 The number of frames that the fade effect lasts. At the end of the
5804 fade-in effect, the output video will have the same intensity as the input video.
5805 At the end of the fade-out transition, the output video will be filled with the
5806 selected @option{color}.
5810 If set to 1, fade only alpha channel, if one exists on the input.
5813 @item start_time, st
5814 Specify the timestamp (in seconds) of the frame to start to apply the fade
5815 effect. If both start_frame and start_time are specified, the fade will start at
5816 whichever comes last. Default is 0.
5819 The number of seconds for which the fade effect has to last. At the end of the
5820 fade-in effect the output video will have the same intensity as the input video,
5821 at the end of the fade-out transition the output video will be filled with the
5822 selected @option{color}.
5823 If both duration and nb_frames are specified, duration is used. Default is 0
5824 (nb_frames is used by default).
5827 Specify the color of the fade. Default is "black".
5830 @subsection Examples
5834 Fade in the first 30 frames of video:
5839 The command above is equivalent to:
5845 Fade out the last 45 frames of a 200-frame video:
5848 fade=type=out:start_frame=155:nb_frames=45
5852 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
5854 fade=in:0:25, fade=out:975:25
5858 Make the first 5 frames yellow, then fade in from frame 5-24:
5860 fade=in:5:20:color=yellow
5864 Fade in alpha over first 25 frames of video:
5866 fade=in:0:25:alpha=1
5870 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
5872 fade=t=in:st=5.5:d=0.5
5878 Apply arbitrary expressions to samples in frequency domain
5882 Adjust the dc value (gain) of the luma plane of the image. The filter
5883 accepts an integer value in range @code{0} to @code{1000}. The default
5884 value is set to @code{0}.
5887 Adjust the dc value (gain) of the 1st chroma plane of the image. The
5888 filter accepts an integer value in range @code{0} to @code{1000}. The
5889 default value is set to @code{0}.
5892 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
5893 filter accepts an integer value in range @code{0} to @code{1000}. The
5894 default value is set to @code{0}.
5897 Set the frequency domain weight expression for the luma plane.
5900 Set the frequency domain weight expression for the 1st chroma plane.
5903 Set the frequency domain weight expression for the 2nd chroma plane.
5905 The filter accepts the following variables:
5908 The coordinates of the current sample.
5912 The width and height of the image.
5915 @subsection Examples
5921 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
5927 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
5933 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
5940 Extract a single field from an interlaced image using stride
5941 arithmetic to avoid wasting CPU time. The output frames are marked as
5944 The filter accepts the following options:
5948 Specify whether to extract the top (if the value is @code{0} or
5949 @code{top}) or the bottom field (if the value is @code{1} or
5955 Field matching filter for inverse telecine. It is meant to reconstruct the
5956 progressive frames from a telecined stream. The filter does not drop duplicated
5957 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
5958 followed by a decimation filter such as @ref{decimate} in the filtergraph.
5960 The separation of the field matching and the decimation is notably motivated by
5961 the possibility of inserting a de-interlacing filter fallback between the two.
5962 If the source has mixed telecined and real interlaced content,
5963 @code{fieldmatch} will not be able to match fields for the interlaced parts.
5964 But these remaining combed frames will be marked as interlaced, and thus can be
5965 de-interlaced by a later filter such as @ref{yadif} before decimation.
5967 In addition to the various configuration options, @code{fieldmatch} can take an
5968 optional second stream, activated through the @option{ppsrc} option. If
5969 enabled, the frames reconstruction will be based on the fields and frames from
5970 this second stream. This allows the first input to be pre-processed in order to
5971 help the various algorithms of the filter, while keeping the output lossless
5972 (assuming the fields are matched properly). Typically, a field-aware denoiser,
5973 or brightness/contrast adjustments can help.
5975 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
5976 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
5977 which @code{fieldmatch} is based on. While the semantic and usage are very
5978 close, some behaviour and options names can differ.
5980 The @ref{decimate} filter currently only works for constant frame rate input.
5981 If your input has mixed telecined (30fps) and progressive content with a lower
5982 framerate like 24fps use the following filterchain to produce the necessary cfr
5983 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
5985 The filter accepts the following options:
5989 Specify the assumed field order of the input stream. Available values are:
5993 Auto detect parity (use FFmpeg's internal parity value).
5995 Assume bottom field first.
5997 Assume top field first.
6000 Note that it is sometimes recommended not to trust the parity announced by the
6003 Default value is @var{auto}.
6006 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
6007 sense that it won't risk creating jerkiness due to duplicate frames when
6008 possible, but if there are bad edits or blended fields it will end up
6009 outputting combed frames when a good match might actually exist. On the other
6010 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
6011 but will almost always find a good frame if there is one. The other values are
6012 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
6013 jerkiness and creating duplicate frames versus finding good matches in sections
6014 with bad edits, orphaned fields, blended fields, etc.
6016 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
6018 Available values are:
6022 2-way matching (p/c)
6024 2-way matching, and trying 3rd match if still combed (p/c + n)
6026 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
6028 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
6029 still combed (p/c + n + u/b)
6031 3-way matching (p/c/n)
6033 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
6034 detected as combed (p/c/n + u/b)
6037 The parenthesis at the end indicate the matches that would be used for that
6038 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
6041 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
6044 Default value is @var{pc_n}.
6047 Mark the main input stream as a pre-processed input, and enable the secondary
6048 input stream as the clean source to pick the fields from. See the filter
6049 introduction for more details. It is similar to the @option{clip2} feature from
6052 Default value is @code{0} (disabled).
6055 Set the field to match from. It is recommended to set this to the same value as
6056 @option{order} unless you experience matching failures with that setting. In
6057 certain circumstances changing the field that is used to match from can have a
6058 large impact on matching performance. Available values are:
6062 Automatic (same value as @option{order}).
6064 Match from the bottom field.
6066 Match from the top field.
6069 Default value is @var{auto}.
6072 Set whether or not chroma is included during the match comparisons. In most
6073 cases it is recommended to leave this enabled. You should set this to @code{0}
6074 only if your clip has bad chroma problems such as heavy rainbowing or other
6075 artifacts. Setting this to @code{0} could also be used to speed things up at
6076 the cost of some accuracy.
6078 Default value is @code{1}.
6082 These define an exclusion band which excludes the lines between @option{y0} and
6083 @option{y1} from being included in the field matching decision. An exclusion
6084 band can be used to ignore subtitles, a logo, or other things that may
6085 interfere with the matching. @option{y0} sets the starting scan line and
6086 @option{y1} sets the ending line; all lines in between @option{y0} and
6087 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
6088 @option{y0} and @option{y1} to the same value will disable the feature.
6089 @option{y0} and @option{y1} defaults to @code{0}.
6092 Set the scene change detection threshold as a percentage of maximum change on
6093 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
6094 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
6095 @option{scthresh} is @code{[0.0, 100.0]}.
6097 Default value is @code{12.0}.
6100 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
6101 account the combed scores of matches when deciding what match to use as the
6102 final match. Available values are:
6106 No final matching based on combed scores.
6108 Combed scores are only used when a scene change is detected.
6110 Use combed scores all the time.
6113 Default is @var{sc}.
6116 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
6117 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
6118 Available values are:
6122 No forced calculation.
6124 Force p/c/n calculations.
6126 Force p/c/n/u/b calculations.
6129 Default value is @var{none}.
6132 This is the area combing threshold used for combed frame detection. This
6133 essentially controls how "strong" or "visible" combing must be to be detected.
6134 Larger values mean combing must be more visible and smaller values mean combing
6135 can be less visible or strong and still be detected. Valid settings are from
6136 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
6137 be detected as combed). This is basically a pixel difference value. A good
6138 range is @code{[8, 12]}.
6140 Default value is @code{9}.
6143 Sets whether or not chroma is considered in the combed frame decision. Only
6144 disable this if your source has chroma problems (rainbowing, etc.) that are
6145 causing problems for the combed frame detection with chroma enabled. Actually,
6146 using @option{chroma}=@var{0} is usually more reliable, except for the case
6147 where there is chroma only combing in the source.
6149 Default value is @code{0}.
6153 Respectively set the x-axis and y-axis size of the window used during combed
6154 frame detection. This has to do with the size of the area in which
6155 @option{combpel} pixels are required to be detected as combed for a frame to be
6156 declared combed. See the @option{combpel} parameter description for more info.
6157 Possible values are any number that is a power of 2 starting at 4 and going up
6160 Default value is @code{16}.
6163 The number of combed pixels inside any of the @option{blocky} by
6164 @option{blockx} size blocks on the frame for the frame to be detected as
6165 combed. While @option{cthresh} controls how "visible" the combing must be, this
6166 setting controls "how much" combing there must be in any localized area (a
6167 window defined by the @option{blockx} and @option{blocky} settings) on the
6168 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
6169 which point no frames will ever be detected as combed). This setting is known
6170 as @option{MI} in TFM/VFM vocabulary.
6172 Default value is @code{80}.
6175 @anchor{p/c/n/u/b meaning}
6176 @subsection p/c/n/u/b meaning
6178 @subsubsection p/c/n
6180 We assume the following telecined stream:
6183 Top fields: 1 2 2 3 4
6184 Bottom fields: 1 2 3 4 4
6187 The numbers correspond to the progressive frame the fields relate to. Here, the
6188 first two frames are progressive, the 3rd and 4th are combed, and so on.
6190 When @code{fieldmatch} is configured to run a matching from bottom
6191 (@option{field}=@var{bottom}) this is how this input stream get transformed:
6196 B 1 2 3 4 4 <-- matching reference
6205 As a result of the field matching, we can see that some frames get duplicated.
6206 To perform a complete inverse telecine, you need to rely on a decimation filter
6207 after this operation. See for instance the @ref{decimate} filter.
6209 The same operation now matching from top fields (@option{field}=@var{top})
6214 T 1 2 2 3 4 <-- matching reference
6224 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
6225 basically, they refer to the frame and field of the opposite parity:
6228 @item @var{p} matches the field of the opposite parity in the previous frame
6229 @item @var{c} matches the field of the opposite parity in the current frame
6230 @item @var{n} matches the field of the opposite parity in the next frame
6235 The @var{u} and @var{b} matching are a bit special in the sense that they match
6236 from the opposite parity flag. In the following examples, we assume that we are
6237 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
6238 'x' is placed above and below each matched fields.
6240 With bottom matching (@option{field}=@var{bottom}):
6245 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
6246 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
6254 With top matching (@option{field}=@var{top}):
6259 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
6260 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
6268 @subsection Examples
6270 Simple IVTC of a top field first telecined stream:
6272 fieldmatch=order=tff:combmatch=none, decimate
6275 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
6277 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
6282 Transform the field order of the input video.
6284 It accepts the following parameters:
6289 The output field order. Valid values are @var{tff} for top field first or @var{bff}
6290 for bottom field first.
6293 The default value is @samp{tff}.
6295 The transformation is done by shifting the picture content up or down
6296 by one line, and filling the remaining line with appropriate picture content.
6297 This method is consistent with most broadcast field order converters.
6299 If the input video is not flagged as being interlaced, or it is already
6300 flagged as being of the required output field order, then this filter does
6301 not alter the incoming video.
6303 It is very useful when converting to or from PAL DV material,
6304 which is bottom field first.
6308 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
6311 @section fifo, afifo
6313 Buffer input images and send them when they are requested.
6315 It is mainly useful when auto-inserted by the libavfilter
6318 It does not take parameters.
6322 Find a rectangular object
6324 It accepts the following options:
6328 Filepath of the object image, needs to be in gray8.
6331 Detection threshold, default is 0.5.
6334 Number of mipmaps, default is 3.
6336 @item xmin, ymin, xmax, ymax
6337 Specifies the rectangle in which to search.
6340 @subsection Examples
6344 Generate a representative palette of a given video using @command{ffmpeg}:
6346 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
6352 Cover a rectangular object
6354 It accepts the following options:
6358 Filepath of the optional cover image, needs to be in yuv420.
6363 It accepts the following values:
6366 cover it by the supplied image
6368 cover it by interpolating the surrounding pixels
6371 Default value is @var{blur}.
6374 @subsection Examples
6378 Generate a representative palette of a given video using @command{ffmpeg}:
6380 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
6387 Convert the input video to one of the specified pixel formats.
6388 Libavfilter will try to pick one that is suitable as input to
6391 It accepts the following parameters:
6395 A '|'-separated list of pixel format names, such as
6396 "pix_fmts=yuv420p|monow|rgb24".
6400 @subsection Examples
6404 Convert the input video to the @var{yuv420p} format
6406 format=pix_fmts=yuv420p
6409 Convert the input video to any of the formats in the list
6411 format=pix_fmts=yuv420p|yuv444p|yuv410p
6418 Convert the video to specified constant frame rate by duplicating or dropping
6419 frames as necessary.
6421 It accepts the following parameters:
6425 The desired output frame rate. The default is @code{25}.
6430 Possible values are:
6433 zero round towards 0
6437 round towards -infinity
6439 round towards +infinity
6443 The default is @code{near}.
6446 Assume the first PTS should be the given value, in seconds. This allows for
6447 padding/trimming at the start of stream. By default, no assumption is made
6448 about the first frame's expected PTS, so no padding or trimming is done.
6449 For example, this could be set to 0 to pad the beginning with duplicates of
6450 the first frame if a video stream starts after the audio stream or to trim any
6451 frames with a negative PTS.
6455 Alternatively, the options can be specified as a flat string:
6456 @var{fps}[:@var{round}].
6458 See also the @ref{setpts} filter.
6460 @subsection Examples
6464 A typical usage in order to set the fps to 25:
6470 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
6472 fps=fps=film:round=near
6478 Pack two different video streams into a stereoscopic video, setting proper
6479 metadata on supported codecs. The two views should have the same size and
6480 framerate and processing will stop when the shorter video ends. Please note
6481 that you may conveniently adjust view properties with the @ref{scale} and
6484 It accepts the following parameters:
6488 The desired packing format. Supported values are:
6493 The views are next to each other (default).
6496 The views are on top of each other.
6499 The views are packed by line.
6502 The views are packed by column.
6505 The views are temporally interleaved.
6514 # Convert left and right views into a frame-sequential video
6515 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
6517 # Convert views into a side-by-side video with the same output resolution as the input
6518 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
6523 Change the frame rate by interpolating new video output frames from the source
6526 This filter is not designed to function correctly with interlaced media. If
6527 you wish to change the frame rate of interlaced media then you are required
6528 to deinterlace before this filter and re-interlace after this filter.
6530 A description of the accepted options follows.
6534 Specify the output frames per second. This option can also be specified
6535 as a value alone. The default is @code{50}.
6538 Specify the start of a range where the output frame will be created as a
6539 linear interpolation of two frames. The range is [@code{0}-@code{255}],
6540 the default is @code{15}.
6543 Specify the end of a range where the output frame will be created as a
6544 linear interpolation of two frames. The range is [@code{0}-@code{255}],
6545 the default is @code{240}.
6548 Specify the level at which a scene change is detected as a value between
6549 0 and 100 to indicate a new scene; a low value reflects a low
6550 probability for the current frame to introduce a new scene, while a higher
6551 value means the current frame is more likely to be one.
6552 The default is @code{7}.
6555 Specify flags influencing the filter process.
6557 Available value for @var{flags} is:
6560 @item scene_change_detect, scd
6561 Enable scene change detection using the value of the option @var{scene}.
6562 This flag is enabled by default.
6568 Select one frame every N-th frame.
6570 This filter accepts the following option:
6573 Select frame after every @code{step} frames.
6574 Allowed values are positive integers higher than 0. Default value is @code{1}.
6580 Apply a frei0r effect to the input video.
6582 To enable the compilation of this filter, you need to install the frei0r
6583 header and configure FFmpeg with @code{--enable-frei0r}.
6585 It accepts the following parameters:
6590 The name of the frei0r effect to load. If the environment variable
6591 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
6592 directories specified by the colon-separated list in @env{FREIOR_PATH}.
6593 Otherwise, the standard frei0r paths are searched, in this order:
6594 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
6595 @file{/usr/lib/frei0r-1/}.
6598 A '|'-separated list of parameters to pass to the frei0r effect.
6602 A frei0r effect parameter can be a boolean (its value is either
6603 "y" or "n"), a double, a color (specified as
6604 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
6605 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
6606 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
6607 @var{X} and @var{Y} are floating point numbers) and/or a string.
6609 The number and types of parameters depend on the loaded effect. If an
6610 effect parameter is not specified, the default value is set.
6612 @subsection Examples
6616 Apply the distort0r effect, setting the first two double parameters:
6618 frei0r=filter_name=distort0r:filter_params=0.5|0.01
6622 Apply the colordistance effect, taking a color as the first parameter:
6624 frei0r=colordistance:0.2/0.3/0.4
6625 frei0r=colordistance:violet
6626 frei0r=colordistance:0x112233
6630 Apply the perspective effect, specifying the top left and top right image
6633 frei0r=perspective:0.2/0.2|0.8/0.2
6637 For more information, see
6638 @url{http://frei0r.dyne.org}
6642 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
6644 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
6645 processing filter, one of them is performed once per block, not per pixel.
6646 This allows for much higher speed.
6648 The filter accepts the following options:
6652 Set quality. This option defines the number of levels for averaging. It accepts
6653 an integer in the range 4-5. Default value is @code{4}.
6656 Force a constant quantization parameter. It accepts an integer in range 0-63.
6657 If not set, the filter will use the QP from the video stream (if available).
6660 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
6661 more details but also more artifacts, while higher values make the image smoother
6662 but also blurrier. Default value is @code{0} − PSNR optimal.
6665 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
6666 option may cause flicker since the B-Frames have often larger QP. Default is
6667 @code{0} (not enabled).
6673 The filter accepts the following options:
6677 Set the luminance expression.
6679 Set the chrominance blue expression.
6681 Set the chrominance red expression.
6683 Set the alpha expression.
6685 Set the red expression.
6687 Set the green expression.
6689 Set the blue expression.
6692 The colorspace is selected according to the specified options. If one
6693 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
6694 options is specified, the filter will automatically select a YCbCr
6695 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
6696 @option{blue_expr} options is specified, it will select an RGB
6699 If one of the chrominance expression is not defined, it falls back on the other
6700 one. If no alpha expression is specified it will evaluate to opaque value.
6701 If none of chrominance expressions are specified, they will evaluate
6702 to the luminance expression.
6704 The expressions can use the following variables and functions:
6708 The sequential number of the filtered frame, starting from @code{0}.
6712 The coordinates of the current sample.
6716 The width and height of the image.
6720 Width and height scale depending on the currently filtered plane. It is the
6721 ratio between the corresponding luma plane number of pixels and the current
6722 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
6723 @code{0.5,0.5} for chroma planes.
6726 Time of the current frame, expressed in seconds.
6729 Return the value of the pixel at location (@var{x},@var{y}) of the current
6733 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
6737 Return the value of the pixel at location (@var{x},@var{y}) of the
6738 blue-difference chroma plane. Return 0 if there is no such plane.
6741 Return the value of the pixel at location (@var{x},@var{y}) of the
6742 red-difference chroma plane. Return 0 if there is no such plane.
6747 Return the value of the pixel at location (@var{x},@var{y}) of the
6748 red/green/blue component. Return 0 if there is no such component.
6751 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
6752 plane. Return 0 if there is no such plane.
6755 For functions, if @var{x} and @var{y} are outside the area, the value will be
6756 automatically clipped to the closer edge.
6758 @subsection Examples
6762 Flip the image horizontally:
6768 Generate a bidimensional sine wave, with angle @code{PI/3} and a
6769 wavelength of 100 pixels:
6771 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
6775 Generate a fancy enigmatic moving light:
6777 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
6781 Generate a quick emboss effect:
6783 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
6787 Modify RGB components depending on pixel position:
6789 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
6793 Create a radial gradient that is the same size as the input (also see
6794 the @ref{vignette} filter):
6796 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
6800 Create a linear gradient to use as a mask for another filter, then
6801 compose with @ref{overlay}. In this example the video will gradually
6802 become more blurry from the top to the bottom of the y-axis as defined
6803 by the linear gradient:
6805 ffmpeg -i input.mp4 -filter_complex "geq=lum=255*(Y/H),format=gray[grad];[0:v]boxblur=4[blur];[blur][grad]alphamerge[alpha];[0:v][alpha]overlay" output.mp4
6811 Fix the banding artifacts that are sometimes introduced into nearly flat
6812 regions by truncation to 8bit color depth.
6813 Interpolate the gradients that should go where the bands are, and
6816 It is designed for playback only. Do not use it prior to
6817 lossy compression, because compression tends to lose the dither and
6818 bring back the bands.
6820 It accepts the following parameters:
6825 The maximum amount by which the filter will change any one pixel. This is also
6826 the threshold for detecting nearly flat regions. Acceptable values range from
6827 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
6831 The neighborhood to fit the gradient to. A larger radius makes for smoother
6832 gradients, but also prevents the filter from modifying the pixels near detailed
6833 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
6834 values will be clipped to the valid range.
6838 Alternatively, the options can be specified as a flat string:
6839 @var{strength}[:@var{radius}]
6841 @subsection Examples
6845 Apply the filter with a @code{3.5} strength and radius of @code{8}:
6851 Specify radius, omitting the strength (which will fall-back to the default
6862 Apply a Hald CLUT to a video stream.
6864 First input is the video stream to process, and second one is the Hald CLUT.
6865 The Hald CLUT input can be a simple picture or a complete video stream.
6867 The filter accepts the following options:
6871 Force termination when the shortest input terminates. Default is @code{0}.
6873 Continue applying the last CLUT after the end of the stream. A value of
6874 @code{0} disable the filter after the last frame of the CLUT is reached.
6875 Default is @code{1}.
6878 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
6879 filters share the same internals).
6881 More information about the Hald CLUT can be found on Eskil Steenberg's website
6882 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
6884 @subsection Workflow examples
6886 @subsubsection Hald CLUT video stream
6888 Generate an identity Hald CLUT stream altered with various effects:
6890 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
6893 Note: make sure you use a lossless codec.
6895 Then use it with @code{haldclut} to apply it on some random stream:
6897 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
6900 The Hald CLUT will be applied to the 10 first seconds (duration of
6901 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
6902 to the remaining frames of the @code{mandelbrot} stream.
6904 @subsubsection Hald CLUT with preview
6906 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
6907 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
6908 biggest possible square starting at the top left of the picture. The remaining
6909 padding pixels (bottom or right) will be ignored. This area can be used to add
6910 a preview of the Hald CLUT.
6912 Typically, the following generated Hald CLUT will be supported by the
6913 @code{haldclut} filter:
6916 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
6917 pad=iw+320 [padded_clut];
6918 smptebars=s=320x256, split [a][b];
6919 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
6920 [main][b] overlay=W-320" -frames:v 1 clut.png
6923 It contains the original and a preview of the effect of the CLUT: SMPTE color
6924 bars are displayed on the right-top, and below the same color bars processed by
6927 Then, the effect of this Hald CLUT can be visualized with:
6929 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
6934 Flip the input video horizontally.
6936 For example, to horizontally flip the input video with @command{ffmpeg}:
6938 ffmpeg -i in.avi -vf "hflip" out.avi
6942 This filter applies a global color histogram equalization on a
6945 It can be used to correct video that has a compressed range of pixel
6946 intensities. The filter redistributes the pixel intensities to
6947 equalize their distribution across the intensity range. It may be
6948 viewed as an "automatically adjusting contrast filter". This filter is
6949 useful only for correcting degraded or poorly captured source
6952 The filter accepts the following options:
6956 Determine the amount of equalization to be applied. As the strength
6957 is reduced, the distribution of pixel intensities more-and-more
6958 approaches that of the input frame. The value must be a float number
6959 in the range [0,1] and defaults to 0.200.
6962 Set the maximum intensity that can generated and scale the output
6963 values appropriately. The strength should be set as desired and then
6964 the intensity can be limited if needed to avoid washing-out. The value
6965 must be a float number in the range [0,1] and defaults to 0.210.
6968 Set the antibanding level. If enabled the filter will randomly vary
6969 the luminance of output pixels by a small amount to avoid banding of
6970 the histogram. Possible values are @code{none}, @code{weak} or
6971 @code{strong}. It defaults to @code{none}.
6976 Compute and draw a color distribution histogram for the input video.
6978 The computed histogram is a representation of the color component
6979 distribution in an image.
6981 The filter accepts the following options:
6987 It accepts the following values:
6990 Standard histogram that displays the color components distribution in an
6991 image. Displays color graph for each color component. Shows distribution of
6992 the Y, U, V, A or R, G, B components, depending on input format, in the
6993 current frame. Below each graph a color component scale meter is shown.
6996 Displays chroma values (U/V color placement) in a two dimensional
6997 graph (which is called a vectorscope). The brighter a pixel in the
6998 vectorscope, the more pixels of the input frame correspond to that pixel
6999 (i.e., more pixels have this chroma value). The V component is displayed on
7000 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
7001 side being V = 255. The U component is displayed on the vertical (Y) axis,
7002 with the top representing U = 0 and the bottom representing U = 255.
7004 The position of a white pixel in the graph corresponds to the chroma value of
7005 a pixel of the input clip. The graph can therefore be used to read the hue
7006 (color flavor) and the saturation (the dominance of the hue in the color). As
7007 the hue of a color changes, it moves around the square. At the center of the
7008 square the saturation is zero, which means that the corresponding pixel has no
7009 color. If the amount of a specific color is increased (while leaving the other
7010 colors unchanged) the saturation increases, and the indicator moves towards
7011 the edge of the square.
7014 Chroma values in vectorscope, similar as @code{color} but actual chroma values
7018 Per row/column color component graph. In row mode, the graph on the left side
7019 represents color component value 0 and the right side represents value = 255.
7020 In column mode, the top side represents color component value = 0 and bottom
7021 side represents value = 255.
7023 Default value is @code{levels}.
7026 Set height of level in @code{levels}. Default value is @code{200}.
7027 Allowed range is [50, 2048].
7030 Set height of color scale in @code{levels}. Default value is @code{12}.
7031 Allowed range is [0, 40].
7034 Set step for @code{waveform} mode. Smaller values are useful to find out how
7035 many values of the same luminance are distributed across input rows/columns.
7036 Default value is @code{10}. Allowed range is [1, 255].
7039 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
7040 Default is @code{row}.
7042 @item waveform_mirror
7043 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
7044 means mirrored. In mirrored mode, higher values will be represented on the left
7045 side for @code{row} mode and at the top for @code{column} mode. Default is
7046 @code{0} (unmirrored).
7049 Set display mode for @code{waveform} and @code{levels}.
7050 It accepts the following values:
7053 Display separate graph for the color components side by side in
7054 @code{row} waveform mode or one below the other in @code{column} waveform mode
7055 for @code{waveform} histogram mode. For @code{levels} histogram mode,
7056 per color component graphs are placed below each other.
7058 Using this display mode in @code{waveform} histogram mode makes it easy to
7059 spot color casts in the highlights and shadows of an image, by comparing the
7060 contours of the top and the bottom graphs of each waveform. Since whites,
7061 grays, and blacks are characterized by exactly equal amounts of red, green,
7062 and blue, neutral areas of the picture should display three waveforms of
7063 roughly equal width/height. If not, the correction is easy to perform by
7064 making level adjustments the three waveforms.
7067 Presents information identical to that in the @code{parade}, except
7068 that the graphs representing color components are superimposed directly
7071 This display mode in @code{waveform} histogram mode makes it easier to spot
7072 relative differences or similarities in overlapping areas of the color
7073 components that are supposed to be identical, such as neutral whites, grays,
7076 Default is @code{parade}.
7079 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
7080 Default is @code{linear}.
7083 Set what color components to display for mode @code{levels}.
7084 Default is @code{7}.
7087 @subsection Examples
7092 Calculate and draw histogram:
7094 ffplay -i input -vf histogram
7102 This is a high precision/quality 3d denoise filter. It aims to reduce
7103 image noise, producing smooth images and making still images really
7104 still. It should enhance compressibility.
7106 It accepts the following optional parameters:
7110 A non-negative floating point number which specifies spatial luma strength.
7113 @item chroma_spatial
7114 A non-negative floating point number which specifies spatial chroma strength.
7115 It defaults to 3.0*@var{luma_spatial}/4.0.
7118 A floating point number which specifies luma temporal strength. It defaults to
7119 6.0*@var{luma_spatial}/4.0.
7122 A floating point number which specifies chroma temporal strength. It defaults to
7123 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
7128 Apply a high-quality magnification filter designed for pixel art. This filter
7129 was originally created by Maxim Stepin.
7131 It accepts the following option:
7135 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
7136 @code{hq3x} and @code{4} for @code{hq4x}.
7137 Default is @code{3}.
7141 Stack input videos horizontally.
7143 All streams must be of same pixel format and of same height.
7145 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
7146 to create same output.
7148 The filter accept the following option:
7152 Set number of input streams. Default is 2.
7157 Modify the hue and/or the saturation of the input.
7159 It accepts the following parameters:
7163 Specify the hue angle as a number of degrees. It accepts an expression,
7164 and defaults to "0".
7167 Specify the saturation in the [-10,10] range. It accepts an expression and
7171 Specify the hue angle as a number of radians. It accepts an
7172 expression, and defaults to "0".
7175 Specify the brightness in the [-10,10] range. It accepts an expression and
7179 @option{h} and @option{H} are mutually exclusive, and can't be
7180 specified at the same time.
7182 The @option{b}, @option{h}, @option{H} and @option{s} option values are
7183 expressions containing the following constants:
7187 frame count of the input frame starting from 0
7190 presentation timestamp of the input frame expressed in time base units
7193 frame rate of the input video, NAN if the input frame rate is unknown
7196 timestamp expressed in seconds, NAN if the input timestamp is unknown
7199 time base of the input video
7202 @subsection Examples
7206 Set the hue to 90 degrees and the saturation to 1.0:
7212 Same command but expressing the hue in radians:
7218 Rotate hue and make the saturation swing between 0
7219 and 2 over a period of 1 second:
7221 hue="H=2*PI*t: s=sin(2*PI*t)+1"
7225 Apply a 3 seconds saturation fade-in effect starting at 0:
7230 The general fade-in expression can be written as:
7232 hue="s=min(0\, max((t-START)/DURATION\, 1))"
7236 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
7238 hue="s=max(0\, min(1\, (8-t)/3))"
7241 The general fade-out expression can be written as:
7243 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
7248 @subsection Commands
7250 This filter supports the following commands:
7256 Modify the hue and/or the saturation and/or brightness of the input video.
7257 The command accepts the same syntax of the corresponding option.
7259 If the specified expression is not valid, it is kept at its current
7265 Detect video interlacing type.
7267 This filter tries to detect if the input frames as interlaced, progressive,
7268 top or bottom field first. It will also try and detect fields that are
7269 repeated between adjacent frames (a sign of telecine).
7271 Single frame detection considers only immediately adjacent frames when classifying each frame.
7272 Multiple frame detection incorporates the classification history of previous frames.
7274 The filter will log these metadata values:
7277 @item single.current_frame
7278 Detected type of current frame using single-frame detection. One of:
7279 ``tff'' (top field first), ``bff'' (bottom field first),
7280 ``progressive'', or ``undetermined''
7283 Cumulative number of frames detected as top field first using single-frame detection.
7286 Cumulative number of frames detected as top field first using multiple-frame detection.
7289 Cumulative number of frames detected as bottom field first using single-frame detection.
7291 @item multiple.current_frame
7292 Detected type of current frame using multiple-frame detection. One of:
7293 ``tff'' (top field first), ``bff'' (bottom field first),
7294 ``progressive'', or ``undetermined''
7297 Cumulative number of frames detected as bottom field first using multiple-frame detection.
7299 @item single.progressive
7300 Cumulative number of frames detected as progressive using single-frame detection.
7302 @item multiple.progressive
7303 Cumulative number of frames detected as progressive using multiple-frame detection.
7305 @item single.undetermined
7306 Cumulative number of frames that could not be classified using single-frame detection.
7308 @item multiple.undetermined
7309 Cumulative number of frames that could not be classified using multiple-frame detection.
7311 @item repeated.current_frame
7312 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
7314 @item repeated.neither
7315 Cumulative number of frames with no repeated field.
7318 Cumulative number of frames with the top field repeated from the previous frame's top field.
7320 @item repeated.bottom
7321 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
7324 The filter accepts the following options:
7328 Set interlacing threshold.
7330 Set progressive threshold.
7332 Threshold for repeated field detection.
7334 Number of frames after which a given frame's contribution to the
7335 statistics is halved (i.e., it contributes only 0.5 to it's
7336 classification). The default of 0 means that all frames seen are given
7337 full weight of 1.0 forever.
7338 @item analyze_interlaced_flag
7339 When this is not 0 then idet will use the specified number of frames to determine
7340 if the interlaced flag is accurate, it will not count undetermined frames.
7341 If the flag is found to be accurate it will be used without any further
7342 computations, if it is found to be inaccurate it will be cleared without any
7343 further computations. This allows inserting the idet filter as a low computational
7344 method to clean up the interlaced flag
7349 Deinterleave or interleave fields.
7351 This filter allows one to process interlaced images fields without
7352 deinterlacing them. Deinterleaving splits the input frame into 2
7353 fields (so called half pictures). Odd lines are moved to the top
7354 half of the output image, even lines to the bottom half.
7355 You can process (filter) them independently and then re-interleave them.
7357 The filter accepts the following options:
7361 @item chroma_mode, c
7363 Available values for @var{luma_mode}, @var{chroma_mode} and
7364 @var{alpha_mode} are:
7370 @item deinterleave, d
7371 Deinterleave fields, placing one above the other.
7374 Interleave fields. Reverse the effect of deinterleaving.
7376 Default value is @code{none}.
7379 @item chroma_swap, cs
7380 @item alpha_swap, as
7381 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
7386 Apply inflate effect to the video.
7388 This filter replaces the pixel by the local(3x3) average by taking into account
7389 only values higher than the pixel.
7391 It accepts the following options:
7398 Limit the maximum change for each plane, default is 65535.
7399 If 0, plane will remain unchanged.
7404 Simple interlacing filter from progressive contents. This interleaves upper (or
7405 lower) lines from odd frames with lower (or upper) lines from even frames,
7406 halving the frame rate and preserving image height.
7409 Original Original New Frame
7410 Frame 'j' Frame 'j+1' (tff)
7411 ========== =========== ==================
7412 Line 0 --------------------> Frame 'j' Line 0
7413 Line 1 Line 1 ----> Frame 'j+1' Line 1
7414 Line 2 ---------------------> Frame 'j' Line 2
7415 Line 3 Line 3 ----> Frame 'j+1' Line 3
7417 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
7420 It accepts the following optional parameters:
7424 This determines whether the interlaced frame is taken from the even
7425 (tff - default) or odd (bff) lines of the progressive frame.
7428 Enable (default) or disable the vertical lowpass filter to avoid twitter
7429 interlacing and reduce moire patterns.
7434 Deinterlace input video by applying Donald Graft's adaptive kernel
7435 deinterling. Work on interlaced parts of a video to produce
7438 The description of the accepted parameters follows.
7442 Set the threshold which affects the filter's tolerance when
7443 determining if a pixel line must be processed. It must be an integer
7444 in the range [0,255] and defaults to 10. A value of 0 will result in
7445 applying the process on every pixels.
7448 Paint pixels exceeding the threshold value to white if set to 1.
7452 Set the fields order. Swap fields if set to 1, leave fields alone if
7456 Enable additional sharpening if set to 1. Default is 0.
7459 Enable twoway sharpening if set to 1. Default is 0.
7462 @subsection Examples
7466 Apply default values:
7468 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
7472 Enable additional sharpening:
7478 Paint processed pixels in white:
7484 @section lenscorrection
7486 Correct radial lens distortion
7488 This filter can be used to correct for radial distortion as can result from the use
7489 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
7490 one can use tools available for example as part of opencv or simply trial-and-error.
7491 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
7492 and extract the k1 and k2 coefficients from the resulting matrix.
7494 Note that effectively the same filter is available in the open-source tools Krita and
7495 Digikam from the KDE project.
7497 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
7498 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
7499 brightness distribution, so you may want to use both filters together in certain
7500 cases, though you will have to take care of ordering, i.e. whether vignetting should
7501 be applied before or after lens correction.
7505 The filter accepts the following options:
7509 Relative x-coordinate of the focal point of the image, and thereby the center of the
7510 distortion. This value has a range [0,1] and is expressed as fractions of the image
7513 Relative y-coordinate of the focal point of the image, and thereby the center of the
7514 distortion. This value has a range [0,1] and is expressed as fractions of the image
7517 Coefficient of the quadratic correction term. 0.5 means no correction.
7519 Coefficient of the double quadratic correction term. 0.5 means no correction.
7522 The formula that generates the correction is:
7524 @var{r_src} = @var{r_tgt} * (1 + @var{k1} * (@var{r_tgt} / @var{r_0})^2 + @var{k2} * (@var{r_tgt} / @var{r_0})^4)
7526 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
7527 distances from the focal point in the source and target images, respectively.
7532 Apply a 3D LUT to an input video.
7534 The filter accepts the following options:
7538 Set the 3D LUT file name.
7540 Currently supported formats:
7552 Select interpolation mode.
7554 Available values are:
7558 Use values from the nearest defined point.
7560 Interpolate values using the 8 points defining a cube.
7562 Interpolate values using a tetrahedron.
7566 @section lut, lutrgb, lutyuv
7568 Compute a look-up table for binding each pixel component input value
7569 to an output value, and apply it to the input video.
7571 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
7572 to an RGB input video.
7574 These filters accept the following parameters:
7577 set first pixel component expression
7579 set second pixel component expression
7581 set third pixel component expression
7583 set fourth pixel component expression, corresponds to the alpha component
7586 set red component expression
7588 set green component expression
7590 set blue component expression
7592 alpha component expression
7595 set Y/luminance component expression
7597 set U/Cb component expression
7599 set V/Cr component expression
7602 Each of them specifies the expression to use for computing the lookup table for
7603 the corresponding pixel component values.
7605 The exact component associated to each of the @var{c*} options depends on the
7608 The @var{lut} filter requires either YUV or RGB pixel formats in input,
7609 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
7611 The expressions can contain the following constants and functions:
7616 The input width and height.
7619 The input value for the pixel component.
7622 The input value, clipped to the @var{minval}-@var{maxval} range.
7625 The maximum value for the pixel component.
7628 The minimum value for the pixel component.
7631 The negated value for the pixel component value, clipped to the
7632 @var{minval}-@var{maxval} range; it corresponds to the expression
7633 "maxval-clipval+minval".
7636 The computed value in @var{val}, clipped to the
7637 @var{minval}-@var{maxval} range.
7639 @item gammaval(gamma)
7640 The computed gamma correction value of the pixel component value,
7641 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
7643 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
7647 All expressions default to "val".
7649 @subsection Examples
7655 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
7656 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
7659 The above is the same as:
7661 lutrgb="r=negval:g=negval:b=negval"
7662 lutyuv="y=negval:u=negval:v=negval"
7672 Remove chroma components, turning the video into a graytone image:
7674 lutyuv="u=128:v=128"
7678 Apply a luma burning effect:
7684 Remove green and blue components:
7690 Set a constant alpha channel value on input:
7692 format=rgba,lutrgb=a="maxval-minval/2"
7696 Correct luminance gamma by a factor of 0.5:
7698 lutyuv=y=gammaval(0.5)
7702 Discard least significant bits of luma:
7704 lutyuv=y='bitand(val, 128+64+32)'
7708 @section maskedmerge
7710 Merge the first input stream with the second input stream using per pixel
7711 weights in the third input stream.
7713 A value of 0 in the third stream pixel component means that pixel component
7714 from first stream is returned unchanged, while maximum value (eg. 255 for
7715 8-bit videos) means that pixel component from second stream is returned
7716 unchanged. Intermediate values define the amount of merging between both
7717 input stream's pixel components.
7719 This filter accepts the following options:
7722 Set which planes will be processed as bitmap, unprocessed planes will be
7723 copied from first stream.
7724 By default value 0xf, all planes will be processed.
7729 Apply motion-compensation deinterlacing.
7731 It needs one field per frame as input and must thus be used together
7732 with yadif=1/3 or equivalent.
7734 This filter accepts the following options:
7737 Set the deinterlacing mode.
7739 It accepts one of the following values:
7744 use iterative motion estimation
7746 like @samp{slow}, but use multiple reference frames.
7748 Default value is @samp{fast}.
7751 Set the picture field parity assumed for the input video. It must be
7752 one of the following values:
7756 assume top field first
7758 assume bottom field first
7761 Default value is @samp{bff}.
7764 Set per-block quantization parameter (QP) used by the internal
7767 Higher values should result in a smoother motion vector field but less
7768 optimal individual vectors. Default value is 1.
7771 @section mergeplanes
7773 Merge color channel components from several video streams.
7775 The filter accepts up to 4 input streams, and merge selected input
7776 planes to the output video.
7778 This filter accepts the following options:
7781 Set input to output plane mapping. Default is @code{0}.
7783 The mappings is specified as a bitmap. It should be specified as a
7784 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
7785 mapping for the first plane of the output stream. 'A' sets the number of
7786 the input stream to use (from 0 to 3), and 'a' the plane number of the
7787 corresponding input to use (from 0 to 3). The rest of the mappings is
7788 similar, 'Bb' describes the mapping for the output stream second
7789 plane, 'Cc' describes the mapping for the output stream third plane and
7790 'Dd' describes the mapping for the output stream fourth plane.
7793 Set output pixel format. Default is @code{yuva444p}.
7796 @subsection Examples
7800 Merge three gray video streams of same width and height into single video stream:
7802 [a0][a1][a2]mergeplanes=0x001020:yuv444p
7806 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
7808 [a0][a1]mergeplanes=0x00010210:yuva444p
7812 Swap Y and A plane in yuva444p stream:
7814 format=yuva444p,mergeplanes=0x03010200:yuva444p
7818 Swap U and V plane in yuv420p stream:
7820 format=yuv420p,mergeplanes=0x000201:yuv420p
7824 Cast a rgb24 clip to yuv444p:
7826 format=rgb24,mergeplanes=0x000102:yuv444p
7832 Drop frames that do not differ greatly from the previous frame in
7833 order to reduce frame rate.
7835 The main use of this filter is for very-low-bitrate encoding
7836 (e.g. streaming over dialup modem), but it could in theory be used for
7837 fixing movies that were inverse-telecined incorrectly.
7839 A description of the accepted options follows.
7843 Set the maximum number of consecutive frames which can be dropped (if
7844 positive), or the minimum interval between dropped frames (if
7845 negative). If the value is 0, the frame is dropped unregarding the
7846 number of previous sequentially dropped frames.
7853 Set the dropping threshold values.
7855 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
7856 represent actual pixel value differences, so a threshold of 64
7857 corresponds to 1 unit of difference for each pixel, or the same spread
7858 out differently over the block.
7860 A frame is a candidate for dropping if no 8x8 blocks differ by more
7861 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
7862 meaning the whole image) differ by more than a threshold of @option{lo}.
7864 Default value for @option{hi} is 64*12, default value for @option{lo} is
7865 64*5, and default value for @option{frac} is 0.33.
7873 It accepts an integer in input; if non-zero it negates the
7874 alpha component (if available). The default value in input is 0.
7878 Force libavfilter not to use any of the specified pixel formats for the
7879 input to the next filter.
7881 It accepts the following parameters:
7885 A '|'-separated list of pixel format names, such as
7886 apix_fmts=yuv420p|monow|rgb24".
7890 @subsection Examples
7894 Force libavfilter to use a format different from @var{yuv420p} for the
7895 input to the vflip filter:
7897 noformat=pix_fmts=yuv420p,vflip
7901 Convert the input video to any of the formats not contained in the list:
7903 noformat=yuv420p|yuv444p|yuv410p
7909 Add noise on video input frame.
7911 The filter accepts the following options:
7919 Set noise seed for specific pixel component or all pixel components in case
7920 of @var{all_seed}. Default value is @code{123457}.
7922 @item all_strength, alls
7923 @item c0_strength, c0s
7924 @item c1_strength, c1s
7925 @item c2_strength, c2s
7926 @item c3_strength, c3s
7927 Set noise strength for specific pixel component or all pixel components in case
7928 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
7930 @item all_flags, allf
7935 Set pixel component flags or set flags for all components if @var{all_flags}.
7936 Available values for component flags are:
7939 averaged temporal noise (smoother)
7941 mix random noise with a (semi)regular pattern
7943 temporal noise (noise pattern changes between frames)
7945 uniform noise (gaussian otherwise)
7949 @subsection Examples
7951 Add temporal and uniform noise to input video:
7953 noise=alls=20:allf=t+u
7958 Pass the video source unchanged to the output.
7961 Optical Character Recognition
7963 This filter uses Tesseract for optical character recognition.
7965 It accepts the following options:
7969 Set datapath to tesseract data. Default is to use whatever was
7970 set at installation.
7973 Set language, default is "eng".
7976 Set character whitelist.
7979 Set character blacklist.
7982 The filter exports recognized text as the frame metadata @code{lavfi.ocr.text}.
7986 Apply a video transform using libopencv.
7988 To enable this filter, install the libopencv library and headers and
7989 configure FFmpeg with @code{--enable-libopencv}.
7991 It accepts the following parameters:
7996 The name of the libopencv filter to apply.
7999 The parameters to pass to the libopencv filter. If not specified, the default
8004 Refer to the official libopencv documentation for more precise
8006 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
8008 Several libopencv filters are supported; see the following subsections.
8013 Dilate an image by using a specific structuring element.
8014 It corresponds to the libopencv function @code{cvDilate}.
8016 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
8018 @var{struct_el} represents a structuring element, and has the syntax:
8019 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
8021 @var{cols} and @var{rows} represent the number of columns and rows of
8022 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
8023 point, and @var{shape} the shape for the structuring element. @var{shape}
8024 must be "rect", "cross", "ellipse", or "custom".
8026 If the value for @var{shape} is "custom", it must be followed by a
8027 string of the form "=@var{filename}". The file with name
8028 @var{filename} is assumed to represent a binary image, with each
8029 printable character corresponding to a bright pixel. When a custom
8030 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
8031 or columns and rows of the read file are assumed instead.
8033 The default value for @var{struct_el} is "3x3+0x0/rect".
8035 @var{nb_iterations} specifies the number of times the transform is
8036 applied to the image, and defaults to 1.
8040 # Use the default values
8043 # Dilate using a structuring element with a 5x5 cross, iterating two times
8044 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
8046 # Read the shape from the file diamond.shape, iterating two times.
8047 # The file diamond.shape may contain a pattern of characters like this
8053 # The specified columns and rows are ignored
8054 # but the anchor point coordinates are not
8055 ocv=dilate:0x0+2x2/custom=diamond.shape|2
8060 Erode an image by using a specific structuring element.
8061 It corresponds to the libopencv function @code{cvErode}.
8063 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
8064 with the same syntax and semantics as the @ref{dilate} filter.
8068 Smooth the input video.
8070 The filter takes the following parameters:
8071 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
8073 @var{type} is the type of smooth filter to apply, and must be one of
8074 the following values: "blur", "blur_no_scale", "median", "gaussian",
8075 or "bilateral". The default value is "gaussian".
8077 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
8078 depend on the smooth type. @var{param1} and
8079 @var{param2} accept integer positive values or 0. @var{param3} and
8080 @var{param4} accept floating point values.
8082 The default value for @var{param1} is 3. The default value for the
8083 other parameters is 0.
8085 These parameters correspond to the parameters assigned to the
8086 libopencv function @code{cvSmooth}.
8091 Overlay one video on top of another.
8093 It takes two inputs and has one output. The first input is the "main"
8094 video on which the second input is overlaid.
8096 It accepts the following parameters:
8098 A description of the accepted options follows.
8103 Set the expression for the x and y coordinates of the overlaid video
8104 on the main video. Default value is "0" for both expressions. In case
8105 the expression is invalid, it is set to a huge value (meaning that the
8106 overlay will not be displayed within the output visible area).
8109 The action to take when EOF is encountered on the secondary input; it accepts
8110 one of the following values:
8114 Repeat the last frame (the default).
8118 Pass the main input through.
8122 Set when the expressions for @option{x}, and @option{y} are evaluated.
8124 It accepts the following values:
8127 only evaluate expressions once during the filter initialization or
8128 when a command is processed
8131 evaluate expressions for each incoming frame
8134 Default value is @samp{frame}.
8137 If set to 1, force the output to terminate when the shortest input
8138 terminates. Default value is 0.
8141 Set the format for the output video.
8143 It accepts the following values:
8158 Default value is @samp{yuv420}.
8160 @item rgb @emph{(deprecated)}
8161 If set to 1, force the filter to accept inputs in the RGB
8162 color space. Default value is 0. This option is deprecated, use
8163 @option{format} instead.
8166 If set to 1, force the filter to draw the last overlay frame over the
8167 main input until the end of the stream. A value of 0 disables this
8168 behavior. Default value is 1.
8171 The @option{x}, and @option{y} expressions can contain the following
8177 The main input width and height.
8181 The overlay input width and height.
8185 The computed values for @var{x} and @var{y}. They are evaluated for
8190 horizontal and vertical chroma subsample values of the output
8191 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
8195 the number of input frame, starting from 0
8198 the position in the file of the input frame, NAN if unknown
8201 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
8205 Note that the @var{n}, @var{pos}, @var{t} variables are available only
8206 when evaluation is done @emph{per frame}, and will evaluate to NAN
8207 when @option{eval} is set to @samp{init}.
8209 Be aware that frames are taken from each input video in timestamp
8210 order, hence, if their initial timestamps differ, it is a good idea
8211 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
8212 have them begin in the same zero timestamp, as the example for
8213 the @var{movie} filter does.
8215 You can chain together more overlays but you should test the
8216 efficiency of such approach.
8218 @subsection Commands
8220 This filter supports the following commands:
8224 Modify the x and y of the overlay input.
8225 The command accepts the same syntax of the corresponding option.
8227 If the specified expression is not valid, it is kept at its current
8231 @subsection Examples
8235 Draw the overlay at 10 pixels from the bottom right corner of the main
8238 overlay=main_w-overlay_w-10:main_h-overlay_h-10
8241 Using named options the example above becomes:
8243 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
8247 Insert a transparent PNG logo in the bottom left corner of the input,
8248 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
8250 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
8254 Insert 2 different transparent PNG logos (second logo on bottom
8255 right corner) using the @command{ffmpeg} tool:
8257 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
8261 Add a transparent color layer on top of the main video; @code{WxH}
8262 must specify the size of the main input to the overlay filter:
8264 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
8268 Play an original video and a filtered version (here with the deshake
8269 filter) side by side using the @command{ffplay} tool:
8271 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
8274 The above command is the same as:
8276 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
8280 Make a sliding overlay appearing from the left to the right top part of the
8281 screen starting since time 2:
8283 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
8287 Compose output by putting two input videos side to side:
8289 ffmpeg -i left.avi -i right.avi -filter_complex "
8290 nullsrc=size=200x100 [background];
8291 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
8292 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
8293 [background][left] overlay=shortest=1 [background+left];
8294 [background+left][right] overlay=shortest=1:x=100 [left+right]
8299 Mask 10-20 seconds of a video by applying the delogo filter to a section
8301 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
8302 -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]'
8307 Chain several overlays in cascade:
8309 nullsrc=s=200x200 [bg];
8310 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
8311 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
8312 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
8313 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
8314 [in3] null, [mid2] overlay=100:100 [out0]
8321 Apply Overcomplete Wavelet denoiser.
8323 The filter accepts the following options:
8329 Larger depth values will denoise lower frequency components more, but
8330 slow down filtering.
8332 Must be an int in the range 8-16, default is @code{8}.
8334 @item luma_strength, ls
8337 Must be a double value in the range 0-1000, default is @code{1.0}.
8339 @item chroma_strength, cs
8340 Set chroma strength.
8342 Must be a double value in the range 0-1000, default is @code{1.0}.
8348 Add paddings to the input image, and place the original input at the
8349 provided @var{x}, @var{y} coordinates.
8351 It accepts the following parameters:
8356 Specify an expression for the size of the output image with the
8357 paddings added. If the value for @var{width} or @var{height} is 0, the
8358 corresponding input size is used for the output.
8360 The @var{width} expression can reference the value set by the
8361 @var{height} expression, and vice versa.
8363 The default value of @var{width} and @var{height} is 0.
8367 Specify the offsets to place the input image at within the padded area,
8368 with respect to the top/left border of the output image.
8370 The @var{x} expression can reference the value set by the @var{y}
8371 expression, and vice versa.
8373 The default value of @var{x} and @var{y} is 0.
8376 Specify the color of the padded area. For the syntax of this option,
8377 check the "Color" section in the ffmpeg-utils manual.
8379 The default value of @var{color} is "black".
8382 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
8383 options are expressions containing the following constants:
8388 The input video width and height.
8392 These are the same as @var{in_w} and @var{in_h}.
8396 The output width and height (the size of the padded area), as
8397 specified by the @var{width} and @var{height} expressions.
8401 These are the same as @var{out_w} and @var{out_h}.
8405 The x and y offsets as specified by the @var{x} and @var{y}
8406 expressions, or NAN if not yet specified.
8409 same as @var{iw} / @var{ih}
8412 input sample aspect ratio
8415 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
8419 The horizontal and vertical chroma subsample values. For example for the
8420 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8423 @subsection Examples
8427 Add paddings with the color "violet" to the input video. The output video
8428 size is 640x480, and the top-left corner of the input video is placed at
8431 pad=640:480:0:40:violet
8434 The example above is equivalent to the following command:
8436 pad=width=640:height=480:x=0:y=40:color=violet
8440 Pad the input to get an output with dimensions increased by 3/2,
8441 and put the input video at the center of the padded area:
8443 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
8447 Pad the input to get a squared output with size equal to the maximum
8448 value between the input width and height, and put the input video at
8449 the center of the padded area:
8451 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
8455 Pad the input to get a final w/h ratio of 16:9:
8457 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
8461 In case of anamorphic video, in order to set the output display aspect
8462 correctly, it is necessary to use @var{sar} in the expression,
8463 according to the relation:
8465 (ih * X / ih) * sar = output_dar
8466 X = output_dar / sar
8469 Thus the previous example needs to be modified to:
8471 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
8475 Double the output size and put the input video in the bottom-right
8476 corner of the output padded area:
8478 pad="2*iw:2*ih:ow-iw:oh-ih"
8485 Generate one palette for a whole video stream.
8487 It accepts the following options:
8491 Set the maximum number of colors to quantize in the palette.
8492 Note: the palette will still contain 256 colors; the unused palette entries
8495 @item reserve_transparent
8496 Create a palette of 255 colors maximum and reserve the last one for
8497 transparency. Reserving the transparency color is useful for GIF optimization.
8498 If not set, the maximum of colors in the palette will be 256. You probably want
8499 to disable this option for a standalone image.
8503 Set statistics mode.
8505 It accepts the following values:
8508 Compute full frame histograms.
8510 Compute histograms only for the part that differs from previous frame. This
8511 might be relevant to give more importance to the moving part of your input if
8512 the background is static.
8515 Default value is @var{full}.
8518 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
8519 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
8520 color quantization of the palette. This information is also visible at
8521 @var{info} logging level.
8523 @subsection Examples
8527 Generate a representative palette of a given video using @command{ffmpeg}:
8529 ffmpeg -i input.mkv -vf palettegen palette.png
8535 Use a palette to downsample an input video stream.
8537 The filter takes two inputs: one video stream and a palette. The palette must
8538 be a 256 pixels image.
8540 It accepts the following options:
8544 Select dithering mode. Available algorithms are:
8547 Ordered 8x8 bayer dithering (deterministic)
8549 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
8550 Note: this dithering is sometimes considered "wrong" and is included as a
8552 @item floyd_steinberg
8553 Floyd and Steingberg dithering (error diffusion)
8555 Frankie Sierra dithering v2 (error diffusion)
8557 Frankie Sierra dithering v2 "Lite" (error diffusion)
8560 Default is @var{sierra2_4a}.
8563 When @var{bayer} dithering is selected, this option defines the scale of the
8564 pattern (how much the crosshatch pattern is visible). A low value means more
8565 visible pattern for less banding, and higher value means less visible pattern
8566 at the cost of more banding.
8568 The option must be an integer value in the range [0,5]. Default is @var{2}.
8571 If set, define the zone to process
8575 Only the changing rectangle will be reprocessed. This is similar to GIF
8576 cropping/offsetting compression mechanism. This option can be useful for speed
8577 if only a part of the image is changing, and has use cases such as limiting the
8578 scope of the error diffusal @option{dither} to the rectangle that bounds the
8579 moving scene (it leads to more deterministic output if the scene doesn't change
8580 much, and as a result less moving noise and better GIF compression).
8583 Default is @var{none}.
8586 @subsection Examples
8590 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
8591 using @command{ffmpeg}:
8593 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
8597 @section perspective
8599 Correct perspective of video not recorded perpendicular to the screen.
8601 A description of the accepted parameters follows.
8612 Set coordinates expression for top left, top right, bottom left and bottom right corners.
8613 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
8614 If the @code{sense} option is set to @code{source}, then the specified points will be sent
8615 to the corners of the destination. If the @code{sense} option is set to @code{destination},
8616 then the corners of the source will be sent to the specified coordinates.
8618 The expressions can use the following variables:
8623 the width and height of video frame.
8627 Set interpolation for perspective correction.
8629 It accepts the following values:
8635 Default value is @samp{linear}.
8638 Set interpretation of coordinate options.
8640 It accepts the following values:
8644 Send point in the source specified by the given coordinates to
8645 the corners of the destination.
8647 @item 1, destination
8649 Send the corners of the source to the point in the destination specified
8650 by the given coordinates.
8652 Default value is @samp{source}.
8658 Delay interlaced video by one field time so that the field order changes.
8660 The intended use is to fix PAL movies that have been captured with the
8661 opposite field order to the film-to-video transfer.
8663 A description of the accepted parameters follows.
8669 It accepts the following values:
8672 Capture field order top-first, transfer bottom-first.
8673 Filter will delay the bottom field.
8676 Capture field order bottom-first, transfer top-first.
8677 Filter will delay the top field.
8680 Capture and transfer with the same field order. This mode only exists
8681 for the documentation of the other options to refer to, but if you
8682 actually select it, the filter will faithfully do nothing.
8685 Capture field order determined automatically by field flags, transfer
8687 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
8688 basis using field flags. If no field information is available,
8689 then this works just like @samp{u}.
8692 Capture unknown or varying, transfer opposite.
8693 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
8694 analyzing the images and selecting the alternative that produces best
8695 match between the fields.
8698 Capture top-first, transfer unknown or varying.
8699 Filter selects among @samp{t} and @samp{p} using image analysis.
8702 Capture bottom-first, transfer unknown or varying.
8703 Filter selects among @samp{b} and @samp{p} using image analysis.
8706 Capture determined by field flags, transfer unknown or varying.
8707 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
8708 image analysis. If no field information is available, then this works just
8709 like @samp{U}. This is the default mode.
8712 Both capture and transfer unknown or varying.
8713 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
8717 @section pixdesctest
8719 Pixel format descriptor test filter, mainly useful for internal
8720 testing. The output video should be equal to the input video.
8724 format=monow, pixdesctest
8727 can be used to test the monowhite pixel format descriptor definition.
8731 Enable the specified chain of postprocessing subfilters using libpostproc. This
8732 library should be automatically selected with a GPL build (@code{--enable-gpl}).
8733 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
8734 Each subfilter and some options have a short and a long name that can be used
8735 interchangeably, i.e. dr/dering are the same.
8737 The filters accept the following options:
8741 Set postprocessing subfilters string.
8744 All subfilters share common options to determine their scope:
8748 Honor the quality commands for this subfilter.
8751 Do chrominance filtering, too (default).
8754 Do luminance filtering only (no chrominance).
8757 Do chrominance filtering only (no luminance).
8760 These options can be appended after the subfilter name, separated by a '|'.
8762 Available subfilters are:
8765 @item hb/hdeblock[|difference[|flatness]]
8766 Horizontal deblocking filter
8769 Difference factor where higher values mean more deblocking (default: @code{32}).
8771 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8774 @item vb/vdeblock[|difference[|flatness]]
8775 Vertical deblocking filter
8778 Difference factor where higher values mean more deblocking (default: @code{32}).
8780 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8783 @item ha/hadeblock[|difference[|flatness]]
8784 Accurate horizontal deblocking filter
8787 Difference factor where higher values mean more deblocking (default: @code{32}).
8789 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8792 @item va/vadeblock[|difference[|flatness]]
8793 Accurate vertical deblocking filter
8796 Difference factor where higher values mean more deblocking (default: @code{32}).
8798 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8802 The horizontal and vertical deblocking filters share the difference and
8803 flatness values so you cannot set different horizontal and vertical
8808 Experimental horizontal deblocking filter
8811 Experimental vertical deblocking filter
8816 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
8819 larger -> stronger filtering
8821 larger -> stronger filtering
8823 larger -> stronger filtering
8826 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
8829 Stretch luminance to @code{0-255}.
8832 @item lb/linblenddeint
8833 Linear blend deinterlacing filter that deinterlaces the given block by
8834 filtering all lines with a @code{(1 2 1)} filter.
8836 @item li/linipoldeint
8837 Linear interpolating deinterlacing filter that deinterlaces the given block by
8838 linearly interpolating every second line.
8840 @item ci/cubicipoldeint
8841 Cubic interpolating deinterlacing filter deinterlaces the given block by
8842 cubically interpolating every second line.
8844 @item md/mediandeint
8845 Median deinterlacing filter that deinterlaces the given block by applying a
8846 median filter to every second line.
8848 @item fd/ffmpegdeint
8849 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
8850 second line with a @code{(-1 4 2 4 -1)} filter.
8853 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
8854 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
8856 @item fq/forceQuant[|quantizer]
8857 Overrides the quantizer table from the input with the constant quantizer you
8865 Default pp filter combination (@code{hb|a,vb|a,dr|a})
8868 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
8871 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
8874 @subsection Examples
8878 Apply horizontal and vertical deblocking, deringing and automatic
8879 brightness/contrast:
8885 Apply default filters without brightness/contrast correction:
8891 Apply default filters and temporal denoiser:
8893 pp=default/tmpnoise|1|2|3
8897 Apply deblocking on luminance only, and switch vertical deblocking on or off
8898 automatically depending on available CPU time:
8905 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
8906 similar to spp = 6 with 7 point DCT, where only the center sample is
8909 The filter accepts the following options:
8913 Force a constant quantization parameter. It accepts an integer in range
8914 0 to 63. If not set, the filter will use the QP from the video stream
8918 Set thresholding mode. Available modes are:
8922 Set hard thresholding.
8924 Set soft thresholding (better de-ringing effect, but likely blurrier).
8926 Set medium thresholding (good results, default).
8932 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
8933 Ratio) between two input videos.
8935 This filter takes in input two input videos, the first input is
8936 considered the "main" source and is passed unchanged to the
8937 output. The second input is used as a "reference" video for computing
8940 Both video inputs must have the same resolution and pixel format for
8941 this filter to work correctly. Also it assumes that both inputs
8942 have the same number of frames, which are compared one by one.
8944 The obtained average PSNR is printed through the logging system.
8946 The filter stores the accumulated MSE (mean squared error) of each
8947 frame, and at the end of the processing it is averaged across all frames
8948 equally, and the following formula is applied to obtain the PSNR:
8951 PSNR = 10*log10(MAX^2/MSE)
8954 Where MAX is the average of the maximum values of each component of the
8957 The description of the accepted parameters follows.
8961 If specified the filter will use the named file to save the PSNR of
8962 each individual frame. When filename equals "-" the data is sent to
8966 The file printed if @var{stats_file} is selected, contains a sequence of
8967 key/value pairs of the form @var{key}:@var{value} for each compared
8970 A description of each shown parameter follows:
8974 sequential number of the input frame, starting from 1
8977 Mean Square Error pixel-by-pixel average difference of the compared
8978 frames, averaged over all the image components.
8980 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
8981 Mean Square Error pixel-by-pixel average difference of the compared
8982 frames for the component specified by the suffix.
8984 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
8985 Peak Signal to Noise ratio of the compared frames for the component
8986 specified by the suffix.
8991 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
8992 [main][ref] psnr="stats_file=stats.log" [out]
8995 On this example the input file being processed is compared with the
8996 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
8997 is stored in @file{stats.log}.
9002 Pulldown reversal (inverse telecine) filter, capable of handling mixed
9003 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
9006 The pullup filter is designed to take advantage of future context in making
9007 its decisions. This filter is stateless in the sense that it does not lock
9008 onto a pattern to follow, but it instead looks forward to the following
9009 fields in order to identify matches and rebuild progressive frames.
9011 To produce content with an even framerate, insert the fps filter after
9012 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
9013 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
9015 The filter accepts the following options:
9022 These options set the amount of "junk" to ignore at the left, right, top, and
9023 bottom of the image, respectively. Left and right are in units of 8 pixels,
9024 while top and bottom are in units of 2 lines.
9025 The default is 8 pixels on each side.
9028 Set the strict breaks. Setting this option to 1 will reduce the chances of
9029 filter generating an occasional mismatched frame, but it may also cause an
9030 excessive number of frames to be dropped during high motion sequences.
9031 Conversely, setting it to -1 will make filter match fields more easily.
9032 This may help processing of video where there is slight blurring between
9033 the fields, but may also cause there to be interlaced frames in the output.
9034 Default value is @code{0}.
9037 Set the metric plane to use. It accepts the following values:
9043 Use chroma blue plane.
9046 Use chroma red plane.
9049 This option may be set to use chroma plane instead of the default luma plane
9050 for doing filter's computations. This may improve accuracy on very clean
9051 source material, but more likely will decrease accuracy, especially if there
9052 is chroma noise (rainbow effect) or any grayscale video.
9053 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
9054 load and make pullup usable in realtime on slow machines.
9057 For best results (without duplicated frames in the output file) it is
9058 necessary to change the output frame rate. For example, to inverse
9059 telecine NTSC input:
9061 ffmpeg -i input -vf pullup -r 24000/1001 ...
9066 Change video quantization parameters (QP).
9068 The filter accepts the following option:
9072 Set expression for quantization parameter.
9075 The expression is evaluated through the eval API and can contain, among others,
9076 the following constants:
9080 1 if index is not 129, 0 otherwise.
9083 Sequentional index starting from -129 to 128.
9086 @subsection Examples
9098 Flush video frames from internal cache of frames into a random order.
9099 No frame is discarded.
9100 Inspired by @ref{frei0r} nervous filter.
9104 Set size in number of frames of internal cache, in range from @code{2} to
9105 @code{512}. Default is @code{30}.
9108 Set seed for random number generator, must be an integer included between
9109 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9110 less than @code{0}, the filter will try to use a good random seed on a
9114 @section removegrain
9116 The removegrain filter is a spatial denoiser for progressive video.
9120 Set mode for the first plane.
9123 Set mode for the second plane.
9126 Set mode for the third plane.
9129 Set mode for the fourth plane.
9132 Range of mode is from 0 to 24. Description of each mode follows:
9136 Leave input plane unchanged. Default.
9139 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
9142 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
9145 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
9148 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
9149 This is equivalent to a median filter.
9152 Line-sensitive clipping giving the minimal change.
9155 Line-sensitive clipping, intermediate.
9158 Line-sensitive clipping, intermediate.
9161 Line-sensitive clipping, intermediate.
9164 Line-sensitive clipping on a line where the neighbours pixels are the closest.
9167 Replaces the target pixel with the closest neighbour.
9170 [1 2 1] horizontal and vertical kernel blur.
9176 Bob mode, interpolates top field from the line where the neighbours
9177 pixels are the closest.
9180 Bob mode, interpolates bottom field from the line where the neighbours
9181 pixels are the closest.
9184 Bob mode, interpolates top field. Same as 13 but with a more complicated
9185 interpolation formula.
9188 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
9189 interpolation formula.
9192 Clips the pixel with the minimum and maximum of respectively the maximum and
9193 minimum of each pair of opposite neighbour pixels.
9196 Line-sensitive clipping using opposite neighbours whose greatest distance from
9197 the current pixel is minimal.
9200 Replaces the pixel with the average of its 8 neighbours.
9203 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
9206 Clips pixels using the averages of opposite neighbour.
9209 Same as mode 21 but simpler and faster.
9212 Small edge and halo removal, but reputed useless.
9220 Suppress a TV station logo, using an image file to determine which
9221 pixels comprise the logo. It works by filling in the pixels that
9222 comprise the logo with neighboring pixels.
9224 The filter accepts the following options:
9228 Set the filter bitmap file, which can be any image format supported by
9229 libavformat. The width and height of the image file must match those of the
9230 video stream being processed.
9233 Pixels in the provided bitmap image with a value of zero are not
9234 considered part of the logo, non-zero pixels are considered part of
9235 the logo. If you use white (255) for the logo and black (0) for the
9236 rest, you will be safe. For making the filter bitmap, it is
9237 recommended to take a screen capture of a black frame with the logo
9238 visible, and then using a threshold filter followed by the erode
9239 filter once or twice.
9241 If needed, little splotches can be fixed manually. Remember that if
9242 logo pixels are not covered, the filter quality will be much
9243 reduced. Marking too many pixels as part of the logo does not hurt as
9244 much, but it will increase the amount of blurring needed to cover over
9245 the image and will destroy more information than necessary, and extra
9246 pixels will slow things down on a large logo.
9248 @section repeatfields
9250 This filter uses the repeat_field flag from the Video ES headers and hard repeats
9251 fields based on its value.
9253 @section reverse, areverse
9257 Warning: This filter requires memory to buffer the entire clip, so trimming
9260 @subsection Examples
9264 Take the first 5 seconds of a clip, and reverse it.
9272 Rotate video by an arbitrary angle expressed in radians.
9274 The filter accepts the following options:
9276 A description of the optional parameters follows.
9279 Set an expression for the angle by which to rotate the input video
9280 clockwise, expressed as a number of radians. A negative value will
9281 result in a counter-clockwise rotation. By default it is set to "0".
9283 This expression is evaluated for each frame.
9286 Set the output width expression, default value is "iw".
9287 This expression is evaluated just once during configuration.
9290 Set the output height expression, default value is "ih".
9291 This expression is evaluated just once during configuration.
9294 Enable bilinear interpolation if set to 1, a value of 0 disables
9295 it. Default value is 1.
9298 Set the color used to fill the output area not covered by the rotated
9299 image. For the general syntax of this option, check the "Color" section in the
9300 ffmpeg-utils manual. If the special value "none" is selected then no
9301 background is printed (useful for example if the background is never shown).
9303 Default value is "black".
9306 The expressions for the angle and the output size can contain the
9307 following constants and functions:
9311 sequential number of the input frame, starting from 0. It is always NAN
9312 before the first frame is filtered.
9315 time in seconds of the input frame, it is set to 0 when the filter is
9316 configured. It is always NAN before the first frame is filtered.
9320 horizontal and vertical chroma subsample values. For example for the
9321 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9325 the input video width and height
9329 the output width and height, that is the size of the padded area as
9330 specified by the @var{width} and @var{height} expressions
9334 the minimal width/height required for completely containing the input
9335 video rotated by @var{a} radians.
9337 These are only available when computing the @option{out_w} and
9338 @option{out_h} expressions.
9341 @subsection Examples
9345 Rotate the input by PI/6 radians clockwise:
9351 Rotate the input by PI/6 radians counter-clockwise:
9357 Rotate the input by 45 degrees clockwise:
9363 Apply a constant rotation with period T, starting from an angle of PI/3:
9365 rotate=PI/3+2*PI*t/T
9369 Make the input video rotation oscillating with a period of T
9370 seconds and an amplitude of A radians:
9372 rotate=A*sin(2*PI/T*t)
9376 Rotate the video, output size is chosen so that the whole rotating
9377 input video is always completely contained in the output:
9379 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
9383 Rotate the video, reduce the output size so that no background is ever
9386 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
9390 @subsection Commands
9392 The filter supports the following commands:
9396 Set the angle expression.
9397 The command accepts the same syntax of the corresponding option.
9399 If the specified expression is not valid, it is kept at its current
9405 Apply Shape Adaptive Blur.
9407 The filter accepts the following options:
9410 @item luma_radius, lr
9411 Set luma blur filter strength, must be a value in range 0.1-4.0, default
9412 value is 1.0. A greater value will result in a more blurred image, and
9413 in slower processing.
9415 @item luma_pre_filter_radius, lpfr
9416 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
9419 @item luma_strength, ls
9420 Set luma maximum difference between pixels to still be considered, must
9421 be a value in the 0.1-100.0 range, default value is 1.0.
9423 @item chroma_radius, cr
9424 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
9425 greater value will result in a more blurred image, and in slower
9428 @item chroma_pre_filter_radius, cpfr
9429 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
9431 @item chroma_strength, cs
9432 Set chroma maximum difference between pixels to still be considered,
9433 must be a value in the 0.1-100.0 range.
9436 Each chroma option value, if not explicitly specified, is set to the
9437 corresponding luma option value.
9442 Scale (resize) the input video, using the libswscale library.
9444 The scale filter forces the output display aspect ratio to be the same
9445 of the input, by changing the output sample aspect ratio.
9447 If the input image format is different from the format requested by
9448 the next filter, the scale filter will convert the input to the
9452 The filter accepts the following options, or any of the options
9453 supported by the libswscale scaler.
9455 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
9456 the complete list of scaler options.
9461 Set the output video dimension expression. Default value is the input
9464 If the value is 0, the input width is used for the output.
9466 If one of the values is -1, the scale filter will use a value that
9467 maintains the aspect ratio of the input image, calculated from the
9468 other specified dimension. If both of them are -1, the input size is
9471 If one of the values is -n with n > 1, the scale filter will also use a value
9472 that maintains the aspect ratio of the input image, calculated from the other
9473 specified dimension. After that it will, however, make sure that the calculated
9474 dimension is divisible by n and adjust the value if necessary.
9476 See below for the list of accepted constants for use in the dimension
9480 Set the interlacing mode. It accepts the following values:
9484 Force interlaced aware scaling.
9487 Do not apply interlaced scaling.
9490 Select interlaced aware scaling depending on whether the source frames
9491 are flagged as interlaced or not.
9494 Default value is @samp{0}.
9497 Set libswscale scaling flags. See
9498 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
9499 complete list of values. If not explicitly specified the filter applies
9503 Set the video size. For the syntax of this option, check the
9504 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9506 @item in_color_matrix
9507 @item out_color_matrix
9508 Set in/output YCbCr color space type.
9510 This allows the autodetected value to be overridden as well as allows forcing
9511 a specific value used for the output and encoder.
9513 If not specified, the color space type depends on the pixel format.
9519 Choose automatically.
9522 Format conforming to International Telecommunication Union (ITU)
9523 Recommendation BT.709.
9526 Set color space conforming to the United States Federal Communications
9527 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
9530 Set color space conforming to:
9534 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
9537 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
9540 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
9545 Set color space conforming to SMPTE ST 240:1999.
9550 Set in/output YCbCr sample range.
9552 This allows the autodetected value to be overridden as well as allows forcing
9553 a specific value used for the output and encoder. If not specified, the
9554 range depends on the pixel format. Possible values:
9558 Choose automatically.
9561 Set full range (0-255 in case of 8-bit luma).
9564 Set "MPEG" range (16-235 in case of 8-bit luma).
9567 @item force_original_aspect_ratio
9568 Enable decreasing or increasing output video width or height if necessary to
9569 keep the original aspect ratio. Possible values:
9573 Scale the video as specified and disable this feature.
9576 The output video dimensions will automatically be decreased if needed.
9579 The output video dimensions will automatically be increased if needed.
9583 One useful instance of this option is that when you know a specific device's
9584 maximum allowed resolution, you can use this to limit the output video to
9585 that, while retaining the aspect ratio. For example, device A allows
9586 1280x720 playback, and your video is 1920x800. Using this option (set it to
9587 decrease) and specifying 1280x720 to the command line makes the output
9590 Please note that this is a different thing than specifying -1 for @option{w}
9591 or @option{h}, you still need to specify the output resolution for this option
9596 The values of the @option{w} and @option{h} options are expressions
9597 containing the following constants:
9602 The input width and height
9606 These are the same as @var{in_w} and @var{in_h}.
9610 The output (scaled) width and height
9614 These are the same as @var{out_w} and @var{out_h}
9617 The same as @var{iw} / @var{ih}
9620 input sample aspect ratio
9623 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
9627 horizontal and vertical input chroma subsample values. For example for the
9628 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9632 horizontal and vertical output chroma subsample values. For example for the
9633 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9636 @subsection Examples
9640 Scale the input video to a size of 200x100
9645 This is equivalent to:
9656 Specify a size abbreviation for the output size:
9661 which can also be written as:
9667 Scale the input to 2x:
9673 The above is the same as:
9679 Scale the input to 2x with forced interlaced scaling:
9681 scale=2*iw:2*ih:interl=1
9685 Scale the input to half size:
9691 Increase the width, and set the height to the same size:
9704 Increase the height, and set the width to 3/2 of the height:
9706 scale=w=3/2*oh:h=3/5*ih
9710 Increase the size, making the size a multiple of the chroma
9713 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
9717 Increase the width to a maximum of 500 pixels,
9718 keeping the same aspect ratio as the input:
9720 scale=w='min(500\, iw*3/2):h=-1'
9724 @subsection Commands
9726 This filter supports the following commands:
9730 Set the output video dimension expression.
9731 The command accepts the same syntax of the corresponding option.
9733 If the specified expression is not valid, it is kept at its current
9739 Scale (resize) the input video, based on a reference video.
9741 See the scale filter for available options, scale2ref supports the same but
9742 uses the reference video instead of the main input as basis.
9744 @subsection Examples
9748 Scale a subtitle stream to match the main video in size before overlaying
9750 'scale2ref[b][a];[a][b]overlay'
9754 @section separatefields
9756 The @code{separatefields} takes a frame-based video input and splits
9757 each frame into its components fields, producing a new half height clip
9758 with twice the frame rate and twice the frame count.
9760 This filter use field-dominance information in frame to decide which
9761 of each pair of fields to place first in the output.
9762 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
9764 @section setdar, setsar
9766 The @code{setdar} filter sets the Display Aspect Ratio for the filter
9769 This is done by changing the specified Sample (aka Pixel) Aspect
9770 Ratio, according to the following equation:
9772 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
9775 Keep in mind that the @code{setdar} filter does not modify the pixel
9776 dimensions of the video frame. Also, the display aspect ratio set by
9777 this filter may be changed by later filters in the filterchain,
9778 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
9781 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
9782 the filter output video.
9784 Note that as a consequence of the application of this filter, the
9785 output display aspect ratio will change according to the equation
9788 Keep in mind that the sample aspect ratio set by the @code{setsar}
9789 filter may be changed by later filters in the filterchain, e.g. if
9790 another "setsar" or a "setdar" filter is applied.
9792 It accepts the following parameters:
9795 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
9796 Set the aspect ratio used by the filter.
9798 The parameter can be a floating point number string, an expression, or
9799 a string of the form @var{num}:@var{den}, where @var{num} and
9800 @var{den} are the numerator and denominator of the aspect ratio. If
9801 the parameter is not specified, it is assumed the value "0".
9802 In case the form "@var{num}:@var{den}" is used, the @code{:} character
9806 Set the maximum integer value to use for expressing numerator and
9807 denominator when reducing the expressed aspect ratio to a rational.
9808 Default value is @code{100}.
9812 The parameter @var{sar} is an expression containing
9813 the following constants:
9817 These are approximated values for the mathematical constants e
9818 (Euler's number), pi (Greek pi), and phi (the golden ratio).
9821 The input width and height.
9824 These are the same as @var{w} / @var{h}.
9827 The input sample aspect ratio.
9830 The input display aspect ratio. It is the same as
9831 (@var{w} / @var{h}) * @var{sar}.
9834 Horizontal and vertical chroma subsample values. For example, for the
9835 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9838 @subsection Examples
9843 To change the display aspect ratio to 16:9, specify one of the following:
9851 To change the sample aspect ratio to 10:11, specify:
9857 To set a display aspect ratio of 16:9, and specify a maximum integer value of
9858 1000 in the aspect ratio reduction, use the command:
9860 setdar=ratio=16/9:max=1000
9868 Force field for the output video frame.
9870 The @code{setfield} filter marks the interlace type field for the
9871 output frames. It does not change the input frame, but only sets the
9872 corresponding property, which affects how the frame is treated by
9873 following filters (e.g. @code{fieldorder} or @code{yadif}).
9875 The filter accepts the following options:
9880 Available values are:
9884 Keep the same field property.
9887 Mark the frame as bottom-field-first.
9890 Mark the frame as top-field-first.
9893 Mark the frame as progressive.
9899 Show a line containing various information for each input video frame.
9900 The input video is not modified.
9902 The shown line contains a sequence of key/value pairs of the form
9903 @var{key}:@var{value}.
9905 The following values are shown in the output:
9909 The (sequential) number of the input frame, starting from 0.
9912 The Presentation TimeStamp of the input frame, expressed as a number of
9913 time base units. The time base unit depends on the filter input pad.
9916 The Presentation TimeStamp of the input frame, expressed as a number of
9920 The position of the frame in the input stream, or -1 if this information is
9921 unavailable and/or meaningless (for example in case of synthetic video).
9924 The pixel format name.
9927 The sample aspect ratio of the input frame, expressed in the form
9928 @var{num}/@var{den}.
9931 The size of the input frame. For the syntax of this option, check the
9932 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9935 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
9936 for bottom field first).
9939 This is 1 if the frame is a key frame, 0 otherwise.
9942 The picture type of the input frame ("I" for an I-frame, "P" for a
9943 P-frame, "B" for a B-frame, or "?" for an unknown type).
9944 Also refer to the documentation of the @code{AVPictureType} enum and of
9945 the @code{av_get_picture_type_char} function defined in
9946 @file{libavutil/avutil.h}.
9949 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
9951 @item plane_checksum
9952 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
9953 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
9956 @section showpalette
9958 Displays the 256 colors palette of each frame. This filter is only relevant for
9959 @var{pal8} pixel format frames.
9961 It accepts the following option:
9965 Set the size of the box used to represent one palette color entry. Default is
9966 @code{30} (for a @code{30x30} pixel box).
9969 @section shuffleframes
9971 Reorder and/or duplicate video frames.
9973 It accepts the following parameters:
9977 Set the destination indexes of input frames.
9978 This is space or '|' separated list of indexes that maps input frames to output
9979 frames. Number of indexes also sets maximal value that each index may have.
9982 The first frame has the index 0. The default is to keep the input unchanged.
9984 Swap second and third frame of every three frames of the input:
9986 ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
9989 @section shuffleplanes
9991 Reorder and/or duplicate video planes.
9993 It accepts the following parameters:
9998 The index of the input plane to be used as the first output plane.
10001 The index of the input plane to be used as the second output plane.
10004 The index of the input plane to be used as the third output plane.
10007 The index of the input plane to be used as the fourth output plane.
10011 The first plane has the index 0. The default is to keep the input unchanged.
10013 Swap the second and third planes of the input:
10015 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
10018 @anchor{signalstats}
10019 @section signalstats
10020 Evaluate various visual metrics that assist in determining issues associated
10021 with the digitization of analog video media.
10023 By default the filter will log these metadata values:
10027 Display the minimal Y value contained within the input frame. Expressed in
10031 Display the Y value at the 10% percentile within the input frame. Expressed in
10035 Display the average Y value within the input frame. Expressed in range of
10039 Display the Y value at the 90% percentile within the input frame. Expressed in
10043 Display the maximum Y value contained within the input frame. Expressed in
10047 Display the minimal U value contained within the input frame. Expressed in
10051 Display the U value at the 10% percentile within the input frame. Expressed in
10055 Display the average U value within the input frame. Expressed in range of
10059 Display the U value at the 90% percentile within the input frame. Expressed in
10063 Display the maximum U value contained within the input frame. Expressed in
10067 Display the minimal V value contained within the input frame. Expressed in
10071 Display the V value at the 10% percentile within the input frame. Expressed in
10075 Display the average V value within the input frame. Expressed in range of
10079 Display the V value at the 90% percentile within the input frame. Expressed in
10083 Display the maximum V value contained within the input frame. Expressed in
10087 Display the minimal saturation value contained within the input frame.
10088 Expressed in range of [0-~181.02].
10091 Display the saturation value at the 10% percentile within the input frame.
10092 Expressed in range of [0-~181.02].
10095 Display the average saturation value within the input frame. Expressed in range
10099 Display the saturation value at the 90% percentile within the input frame.
10100 Expressed in range of [0-~181.02].
10103 Display the maximum saturation value contained within the input frame.
10104 Expressed in range of [0-~181.02].
10107 Display the median value for hue within the input frame. Expressed in range of
10111 Display the average value for hue within the input frame. Expressed in range of
10115 Display the average of sample value difference between all values of the Y
10116 plane in the current frame and corresponding values of the previous input frame.
10117 Expressed in range of [0-255].
10120 Display the average of sample value difference between all values of the U
10121 plane in the current frame and corresponding values of the previous input frame.
10122 Expressed in range of [0-255].
10125 Display the average of sample value difference between all values of the V
10126 plane in the current frame and corresponding values of the previous input frame.
10127 Expressed in range of [0-255].
10130 The filter accepts the following options:
10136 @option{stat} specify an additional form of image analysis.
10137 @option{out} output video with the specified type of pixel highlighted.
10139 Both options accept the following values:
10143 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
10144 unlike the neighboring pixels of the same field. Examples of temporal outliers
10145 include the results of video dropouts, head clogs, or tape tracking issues.
10148 Identify @var{vertical line repetition}. Vertical line repetition includes
10149 similar rows of pixels within a frame. In born-digital video vertical line
10150 repetition is common, but this pattern is uncommon in video digitized from an
10151 analog source. When it occurs in video that results from the digitization of an
10152 analog source it can indicate concealment from a dropout compensator.
10155 Identify pixels that fall outside of legal broadcast range.
10159 Set the highlight color for the @option{out} option. The default color is
10163 @subsection Examples
10167 Output data of various video metrics:
10169 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
10173 Output specific data about the minimum and maximum values of the Y plane per frame:
10175 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
10179 Playback video while highlighting pixels that are outside of broadcast range in red.
10181 ffplay example.mov -vf signalstats="out=brng:color=red"
10185 Playback video with signalstats metadata drawn over the frame.
10187 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
10190 The contents of signalstat_drawtext.txt used in the command are:
10193 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
10194 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
10195 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
10196 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
10204 Blur the input video without impacting the outlines.
10206 It accepts the following options:
10209 @item luma_radius, lr
10210 Set the luma radius. The option value must be a float number in
10211 the range [0.1,5.0] that specifies the variance of the gaussian filter
10212 used to blur the image (slower if larger). Default value is 1.0.
10214 @item luma_strength, ls
10215 Set the luma strength. The option value must be a float number
10216 in the range [-1.0,1.0] that configures the blurring. A value included
10217 in [0.0,1.0] will blur the image whereas a value included in
10218 [-1.0,0.0] will sharpen the image. Default value is 1.0.
10220 @item luma_threshold, lt
10221 Set the luma threshold used as a coefficient to determine
10222 whether a pixel should be blurred or not. The option value must be an
10223 integer in the range [-30,30]. A value of 0 will filter all the image,
10224 a value included in [0,30] will filter flat areas and a value included
10225 in [-30,0] will filter edges. Default value is 0.
10227 @item chroma_radius, cr
10228 Set the chroma radius. The option value must be a float number in
10229 the range [0.1,5.0] that specifies the variance of the gaussian filter
10230 used to blur the image (slower if larger). Default value is 1.0.
10232 @item chroma_strength, cs
10233 Set the chroma strength. The option value must be a float number
10234 in the range [-1.0,1.0] that configures the blurring. A value included
10235 in [0.0,1.0] will blur the image whereas a value included in
10236 [-1.0,0.0] will sharpen the image. Default value is 1.0.
10238 @item chroma_threshold, ct
10239 Set the chroma threshold used as a coefficient to determine
10240 whether a pixel should be blurred or not. The option value must be an
10241 integer in the range [-30,30]. A value of 0 will filter all the image,
10242 a value included in [0,30] will filter flat areas and a value included
10243 in [-30,0] will filter edges. Default value is 0.
10246 If a chroma option is not explicitly set, the corresponding luma value
10251 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
10253 This filter takes in input two input videos, the first input is
10254 considered the "main" source and is passed unchanged to the
10255 output. The second input is used as a "reference" video for computing
10258 Both video inputs must have the same resolution and pixel format for
10259 this filter to work correctly. Also it assumes that both inputs
10260 have the same number of frames, which are compared one by one.
10262 The filter stores the calculated SSIM of each frame.
10264 The description of the accepted parameters follows.
10267 @item stats_file, f
10268 If specified the filter will use the named file to save the SSIM of
10269 each individual frame. When filename equals "-" the data is sent to
10273 The file printed if @var{stats_file} is selected, contains a sequence of
10274 key/value pairs of the form @var{key}:@var{value} for each compared
10277 A description of each shown parameter follows:
10281 sequential number of the input frame, starting from 1
10283 @item Y, U, V, R, G, B
10284 SSIM of the compared frames for the component specified by the suffix.
10287 SSIM of the compared frames for the whole frame.
10290 Same as above but in dB representation.
10295 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
10296 [main][ref] ssim="stats_file=stats.log" [out]
10299 On this example the input file being processed is compared with the
10300 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
10301 is stored in @file{stats.log}.
10303 Another example with both psnr and ssim at same time:
10305 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
10310 Convert between different stereoscopic image formats.
10312 The filters accept the following options:
10316 Set stereoscopic image format of input.
10318 Available values for input image formats are:
10321 side by side parallel (left eye left, right eye right)
10324 side by side crosseye (right eye left, left eye right)
10327 side by side parallel with half width resolution
10328 (left eye left, right eye right)
10331 side by side crosseye with half width resolution
10332 (right eye left, left eye right)
10335 above-below (left eye above, right eye below)
10338 above-below (right eye above, left eye below)
10341 above-below with half height resolution
10342 (left eye above, right eye below)
10345 above-below with half height resolution
10346 (right eye above, left eye below)
10349 alternating frames (left eye first, right eye second)
10352 alternating frames (right eye first, left eye second)
10355 interleaved rows (left eye has top row, right eye starts on next row)
10358 interleaved rows (right eye has top row, left eye starts on next row)
10360 Default value is @samp{sbsl}.
10364 Set stereoscopic image format of output.
10366 Available values for output image formats are all the input formats as well as:
10369 anaglyph red/blue gray
10370 (red filter on left eye, blue filter on right eye)
10373 anaglyph red/green gray
10374 (red filter on left eye, green filter on right eye)
10377 anaglyph red/cyan gray
10378 (red filter on left eye, cyan filter on right eye)
10381 anaglyph red/cyan half colored
10382 (red filter on left eye, cyan filter on right eye)
10385 anaglyph red/cyan color
10386 (red filter on left eye, cyan filter on right eye)
10389 anaglyph red/cyan color optimized with the least squares projection of dubois
10390 (red filter on left eye, cyan filter on right eye)
10393 anaglyph green/magenta gray
10394 (green filter on left eye, magenta filter on right eye)
10397 anaglyph green/magenta half colored
10398 (green filter on left eye, magenta filter on right eye)
10401 anaglyph green/magenta colored
10402 (green filter on left eye, magenta filter on right eye)
10405 anaglyph green/magenta color optimized with the least squares projection of dubois
10406 (green filter on left eye, magenta filter on right eye)
10409 anaglyph yellow/blue gray
10410 (yellow filter on left eye, blue filter on right eye)
10413 anaglyph yellow/blue half colored
10414 (yellow filter on left eye, blue filter on right eye)
10417 anaglyph yellow/blue colored
10418 (yellow filter on left eye, blue filter on right eye)
10421 anaglyph yellow/blue color optimized with the least squares projection of dubois
10422 (yellow filter on left eye, blue filter on right eye)
10425 mono output (left eye only)
10428 mono output (right eye only)
10431 checkerboard, left eye first
10434 checkerboard, right eye first
10437 interleaved columns, left eye first
10440 interleaved columns, right eye first
10443 Default value is @samp{arcd}.
10446 @subsection Examples
10450 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
10456 Convert input video from above below (left eye above, right eye below) to side by side crosseye.
10465 Apply a simple postprocessing filter that compresses and decompresses the image
10466 at several (or - in the case of @option{quality} level @code{6} - all) shifts
10467 and average the results.
10469 The filter accepts the following options:
10473 Set quality. This option defines the number of levels for averaging. It accepts
10474 an integer in the range 0-6. If set to @code{0}, the filter will have no
10475 effect. A value of @code{6} means the higher quality. For each increment of
10476 that value the speed drops by a factor of approximately 2. Default value is
10480 Force a constant quantization parameter. If not set, the filter will use the QP
10481 from the video stream (if available).
10484 Set thresholding mode. Available modes are:
10488 Set hard thresholding (default).
10490 Set soft thresholding (better de-ringing effect, but likely blurrier).
10493 @item use_bframe_qp
10494 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
10495 option may cause flicker since the B-Frames have often larger QP. Default is
10496 @code{0} (not enabled).
10502 Draw subtitles on top of input video using the libass library.
10504 To enable compilation of this filter you need to configure FFmpeg with
10505 @code{--enable-libass}. This filter also requires a build with libavcodec and
10506 libavformat to convert the passed subtitles file to ASS (Advanced Substation
10507 Alpha) subtitles format.
10509 The filter accepts the following options:
10513 Set the filename of the subtitle file to read. It must be specified.
10515 @item original_size
10516 Specify the size of the original video, the video for which the ASS file
10517 was composed. For the syntax of this option, check the
10518 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10519 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
10520 correctly scale the fonts if the aspect ratio has been changed.
10523 Set a directory path containing fonts that can be used by the filter.
10524 These fonts will be used in addition to whatever the font provider uses.
10527 Set subtitles input character encoding. @code{subtitles} filter only. Only
10528 useful if not UTF-8.
10530 @item stream_index, si
10531 Set subtitles stream index. @code{subtitles} filter only.
10534 Override default style or script info parameters of the subtitles. It accepts a
10535 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
10538 If the first key is not specified, it is assumed that the first value
10539 specifies the @option{filename}.
10541 For example, to render the file @file{sub.srt} on top of the input
10542 video, use the command:
10547 which is equivalent to:
10549 subtitles=filename=sub.srt
10552 To render the default subtitles stream from file @file{video.mkv}, use:
10554 subtitles=video.mkv
10557 To render the second subtitles stream from that file, use:
10559 subtitles=video.mkv:si=1
10562 To make the subtitles stream from @file{sub.srt} appear in transparent green
10563 @code{DejaVu Serif}, use:
10565 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
10568 @section super2xsai
10570 Scale the input by 2x and smooth using the Super2xSaI (Scale and
10571 Interpolate) pixel art scaling algorithm.
10573 Useful for enlarging pixel art images without reducing sharpness.
10580 Apply telecine process to the video.
10582 This filter accepts the following options:
10591 The default value is @code{top}.
10595 A string of numbers representing the pulldown pattern you wish to apply.
10596 The default value is @code{23}.
10600 Some typical patterns:
10605 24p: 2332 (preferred)
10612 24p: 222222222223 ("Euro pulldown")
10618 Select the most representative frame in a given sequence of consecutive frames.
10620 The filter accepts the following options:
10624 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
10625 will pick one of them, and then handle the next batch of @var{n} frames until
10626 the end. Default is @code{100}.
10629 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
10630 value will result in a higher memory usage, so a high value is not recommended.
10632 @subsection Examples
10636 Extract one picture each 50 frames:
10642 Complete example of a thumbnail creation with @command{ffmpeg}:
10644 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
10650 Tile several successive frames together.
10652 The filter accepts the following options:
10657 Set the grid size (i.e. the number of lines and columns). For the syntax of
10658 this option, check the
10659 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10662 Set the maximum number of frames to render in the given area. It must be less
10663 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
10664 the area will be used.
10667 Set the outer border margin in pixels.
10670 Set the inner border thickness (i.e. the number of pixels between frames). For
10671 more advanced padding options (such as having different values for the edges),
10672 refer to the pad video filter.
10675 Specify the color of the unused area. For the syntax of this option, check the
10676 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
10680 @subsection Examples
10684 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
10686 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
10688 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
10689 duplicating each output frame to accommodate the originally detected frame
10693 Display @code{5} pictures in an area of @code{3x2} frames,
10694 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
10695 mixed flat and named options:
10697 tile=3x2:nb_frames=5:padding=7:margin=2
10701 @section tinterlace
10703 Perform various types of temporal field interlacing.
10705 Frames are counted starting from 1, so the first input frame is
10708 The filter accepts the following options:
10713 Specify the mode of the interlacing. This option can also be specified
10714 as a value alone. See below for a list of values for this option.
10716 Available values are:
10720 Move odd frames into the upper field, even into the lower field,
10721 generating a double height frame at half frame rate.
10725 Frame 1 Frame 2 Frame 3 Frame 4
10727 11111 22222 33333 44444
10728 11111 22222 33333 44444
10729 11111 22222 33333 44444
10730 11111 22222 33333 44444
10744 Only output even frames, odd frames are dropped, generating a frame with
10745 unchanged height at half frame rate.
10750 Frame 1 Frame 2 Frame 3 Frame 4
10752 11111 22222 33333 44444
10753 11111 22222 33333 44444
10754 11111 22222 33333 44444
10755 11111 22222 33333 44444
10765 Only output odd frames, even frames are dropped, generating a frame with
10766 unchanged height at half frame rate.
10771 Frame 1 Frame 2 Frame 3 Frame 4
10773 11111 22222 33333 44444
10774 11111 22222 33333 44444
10775 11111 22222 33333 44444
10776 11111 22222 33333 44444
10786 Expand each frame to full height, but pad alternate lines with black,
10787 generating a frame with double height at the same input frame rate.
10792 Frame 1 Frame 2 Frame 3 Frame 4
10794 11111 22222 33333 44444
10795 11111 22222 33333 44444
10796 11111 22222 33333 44444
10797 11111 22222 33333 44444
10800 11111 ..... 33333 .....
10801 ..... 22222 ..... 44444
10802 11111 ..... 33333 .....
10803 ..... 22222 ..... 44444
10804 11111 ..... 33333 .....
10805 ..... 22222 ..... 44444
10806 11111 ..... 33333 .....
10807 ..... 22222 ..... 44444
10811 @item interleave_top, 4
10812 Interleave the upper field from odd frames with the lower field from
10813 even frames, generating a frame with unchanged height at half frame rate.
10818 Frame 1 Frame 2 Frame 3 Frame 4
10820 11111<- 22222 33333<- 44444
10821 11111 22222<- 33333 44444<-
10822 11111<- 22222 33333<- 44444
10823 11111 22222<- 33333 44444<-
10833 @item interleave_bottom, 5
10834 Interleave the lower field from odd frames with the upper field from
10835 even frames, generating a frame with unchanged height at half frame rate.
10840 Frame 1 Frame 2 Frame 3 Frame 4
10842 11111 22222<- 33333 44444<-
10843 11111<- 22222 33333<- 44444
10844 11111 22222<- 33333 44444<-
10845 11111<- 22222 33333<- 44444
10855 @item interlacex2, 6
10856 Double frame rate with unchanged height. Frames are inserted each
10857 containing the second temporal field from the previous input frame and
10858 the first temporal field from the next input frame. This mode relies on
10859 the top_field_first flag. Useful for interlaced video displays with no
10860 field synchronisation.
10865 Frame 1 Frame 2 Frame 3 Frame 4
10867 11111 22222 33333 44444
10868 11111 22222 33333 44444
10869 11111 22222 33333 44444
10870 11111 22222 33333 44444
10873 11111 22222 22222 33333 33333 44444 44444
10874 11111 11111 22222 22222 33333 33333 44444
10875 11111 22222 22222 33333 33333 44444 44444
10876 11111 11111 22222 22222 33333 33333 44444
10880 Move odd frames into the upper field, even into the lower field,
10881 generating a double height frame at same frame rate.
10885 Frame 1 Frame 2 Frame 3 Frame 4
10887 11111 22222 33333 44444
10888 11111 22222 33333 44444
10889 11111 22222 33333 44444
10890 11111 22222 33333 44444
10893 11111 33333 33333 55555
10894 22222 22222 44444 44444
10895 11111 33333 33333 55555
10896 22222 22222 44444 44444
10897 11111 33333 33333 55555
10898 22222 22222 44444 44444
10899 11111 33333 33333 55555
10900 22222 22222 44444 44444
10905 Numeric values are deprecated but are accepted for backward
10906 compatibility reasons.
10908 Default mode is @code{merge}.
10911 Specify flags influencing the filter process.
10913 Available value for @var{flags} is:
10916 @item low_pass_filter, vlfp
10917 Enable vertical low-pass filtering in the filter.
10918 Vertical low-pass filtering is required when creating an interlaced
10919 destination from a progressive source which contains high-frequency
10920 vertical detail. Filtering will reduce interlace 'twitter' and Moire
10923 Vertical low-pass filtering can only be enabled for @option{mode}
10924 @var{interleave_top} and @var{interleave_bottom}.
10931 Transpose rows with columns in the input video and optionally flip it.
10933 It accepts the following parameters:
10938 Specify the transposition direction.
10940 Can assume the following values:
10942 @item 0, 4, cclock_flip
10943 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
10951 Rotate by 90 degrees clockwise, that is:
10959 Rotate by 90 degrees counterclockwise, that is:
10966 @item 3, 7, clock_flip
10967 Rotate by 90 degrees clockwise and vertically flip, that is:
10975 For values between 4-7, the transposition is only done if the input
10976 video geometry is portrait and not landscape. These values are
10977 deprecated, the @code{passthrough} option should be used instead.
10979 Numerical values are deprecated, and should be dropped in favor of
10980 symbolic constants.
10983 Do not apply the transposition if the input geometry matches the one
10984 specified by the specified value. It accepts the following values:
10987 Always apply transposition.
10989 Preserve portrait geometry (when @var{height} >= @var{width}).
10991 Preserve landscape geometry (when @var{width} >= @var{height}).
10994 Default value is @code{none}.
10997 For example to rotate by 90 degrees clockwise and preserve portrait
11000 transpose=dir=1:passthrough=portrait
11003 The command above can also be specified as:
11005 transpose=1:portrait
11009 Trim the input so that the output contains one continuous subpart of the input.
11011 It accepts the following parameters:
11014 Specify the time of the start of the kept section, i.e. the frame with the
11015 timestamp @var{start} will be the first frame in the output.
11018 Specify the time of the first frame that will be dropped, i.e. the frame
11019 immediately preceding the one with the timestamp @var{end} will be the last
11020 frame in the output.
11023 This is the same as @var{start}, except this option sets the start timestamp
11024 in timebase units instead of seconds.
11027 This is the same as @var{end}, except this option sets the end timestamp
11028 in timebase units instead of seconds.
11031 The maximum duration of the output in seconds.
11034 The number of the first frame that should be passed to the output.
11037 The number of the first frame that should be dropped.
11040 @option{start}, @option{end}, and @option{duration} are expressed as time
11041 duration specifications; see
11042 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
11043 for the accepted syntax.
11045 Note that the first two sets of the start/end options and the @option{duration}
11046 option look at the frame timestamp, while the _frame variants simply count the
11047 frames that pass through the filter. Also note that this filter does not modify
11048 the timestamps. If you wish for the output timestamps to start at zero, insert a
11049 setpts filter after the trim filter.
11051 If multiple start or end options are set, this filter tries to be greedy and
11052 keep all the frames that match at least one of the specified constraints. To keep
11053 only the part that matches all the constraints at once, chain multiple trim
11056 The defaults are such that all the input is kept. So it is possible to set e.g.
11057 just the end values to keep everything before the specified time.
11062 Drop everything except the second minute of input:
11064 ffmpeg -i INPUT -vf trim=60:120
11068 Keep only the first second:
11070 ffmpeg -i INPUT -vf trim=duration=1
11079 Sharpen or blur the input video.
11081 It accepts the following parameters:
11084 @item luma_msize_x, lx
11085 Set the luma matrix horizontal size. It must be an odd integer between
11086 3 and 63. The default value is 5.
11088 @item luma_msize_y, ly
11089 Set the luma matrix vertical size. It must be an odd integer between 3
11090 and 63. The default value is 5.
11092 @item luma_amount, la
11093 Set the luma effect strength. It must be a floating point number, reasonable
11094 values lay between -1.5 and 1.5.
11096 Negative values will blur the input video, while positive values will
11097 sharpen it, a value of zero will disable the effect.
11099 Default value is 1.0.
11101 @item chroma_msize_x, cx
11102 Set the chroma matrix horizontal size. It must be an odd integer
11103 between 3 and 63. The default value is 5.
11105 @item chroma_msize_y, cy
11106 Set the chroma matrix vertical size. It must be an odd integer
11107 between 3 and 63. The default value is 5.
11109 @item chroma_amount, ca
11110 Set the chroma effect strength. It must be a floating point number, reasonable
11111 values lay between -1.5 and 1.5.
11113 Negative values will blur the input video, while positive values will
11114 sharpen it, a value of zero will disable the effect.
11116 Default value is 0.0.
11119 If set to 1, specify using OpenCL capabilities, only available if
11120 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
11124 All parameters are optional and default to the equivalent of the
11125 string '5:5:1.0:5:5:0.0'.
11127 @subsection Examples
11131 Apply strong luma sharpen effect:
11133 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
11137 Apply a strong blur of both luma and chroma parameters:
11139 unsharp=7:7:-2:7:7:-2
11145 Apply ultra slow/simple postprocessing filter that compresses and decompresses
11146 the image at several (or - in the case of @option{quality} level @code{8} - all)
11147 shifts and average the results.
11149 The way this differs from the behavior of spp is that uspp actually encodes &
11150 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
11151 DCT similar to MJPEG.
11153 The filter accepts the following options:
11157 Set quality. This option defines the number of levels for averaging. It accepts
11158 an integer in the range 0-8. If set to @code{0}, the filter will have no
11159 effect. A value of @code{8} means the higher quality. For each increment of
11160 that value the speed drops by a factor of approximately 2. Default value is
11164 Force a constant quantization parameter. If not set, the filter will use the QP
11165 from the video stream (if available).
11168 @section vectorscope
11170 Display 2 color component values in the two dimensional graph (which is called
11173 This filter accepts the following options:
11177 Set vectorscope mode.
11179 It accepts the following values:
11182 Gray values are displayed on graph, higher brightness means more pixels have
11183 same component color value on location in graph. This is the default mode.
11186 Gray values are displayed on graph. Surrounding pixels values which are not
11187 present in video frame are drawn in gradient of 2 color components which are
11188 set by option @code{x} and @code{y}.
11191 Actual color components values present in video frame are displayed on graph.
11194 Similar as color2 but higher frequency of same values @code{x} and @code{y}
11195 on graph increases value of another color component, which is luminance by
11196 default values of @code{x} and @code{y}.
11199 Actual colors present in video frame are displayed on graph. If two different
11200 colors map to same position on graph then color with higher value of component
11201 not present in graph is picked.
11205 Set which color component will be represented on X-axis. Default is @code{1}.
11208 Set which color component will be represented on Y-axis. Default is @code{2}.
11211 Set intensity, used by modes: gray, color and color3 for increasing brightness
11212 of color component which represents frequency of (X, Y) location in graph.
11217 No envelope, this is default.
11220 Instant envelope, even darkest single pixel will be clearly highlighted.
11223 Hold maximum and minimum values presented in graph over time. This way you
11224 can still spot out of range values without constantly looking at vectorscope.
11227 Peak and instant envelope combined together.
11231 @anchor{vidstabdetect}
11232 @section vidstabdetect
11234 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
11235 @ref{vidstabtransform} for pass 2.
11237 This filter generates a file with relative translation and rotation
11238 transform information about subsequent frames, which is then used by
11239 the @ref{vidstabtransform} filter.
11241 To enable compilation of this filter you need to configure FFmpeg with
11242 @code{--enable-libvidstab}.
11244 This filter accepts the following options:
11248 Set the path to the file used to write the transforms information.
11249 Default value is @file{transforms.trf}.
11252 Set how shaky the video is and how quick the camera is. It accepts an
11253 integer in the range 1-10, a value of 1 means little shakiness, a
11254 value of 10 means strong shakiness. Default value is 5.
11257 Set the accuracy of the detection process. It must be a value in the
11258 range 1-15. A value of 1 means low accuracy, a value of 15 means high
11259 accuracy. Default value is 15.
11262 Set stepsize of the search process. The region around minimum is
11263 scanned with 1 pixel resolution. Default value is 6.
11266 Set minimum contrast. Below this value a local measurement field is
11267 discarded. Must be a floating point value in the range 0-1. Default
11271 Set reference frame number for tripod mode.
11273 If enabled, the motion of the frames is compared to a reference frame
11274 in the filtered stream, identified by the specified number. The idea
11275 is to compensate all movements in a more-or-less static scene and keep
11276 the camera view absolutely still.
11278 If set to 0, it is disabled. The frames are counted starting from 1.
11281 Show fields and transforms in the resulting frames. It accepts an
11282 integer in the range 0-2. Default value is 0, which disables any
11286 @subsection Examples
11290 Use default values:
11296 Analyze strongly shaky movie and put the results in file
11297 @file{mytransforms.trf}:
11299 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
11303 Visualize the result of internal transformations in the resulting
11306 vidstabdetect=show=1
11310 Analyze a video with medium shakiness using @command{ffmpeg}:
11312 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
11316 @anchor{vidstabtransform}
11317 @section vidstabtransform
11319 Video stabilization/deshaking: pass 2 of 2,
11320 see @ref{vidstabdetect} for pass 1.
11322 Read a file with transform information for each frame and
11323 apply/compensate them. Together with the @ref{vidstabdetect}
11324 filter this can be used to deshake videos. See also
11325 @url{http://public.hronopik.de/vid.stab}. It is important to also use
11326 the @ref{unsharp} filter, see below.
11328 To enable compilation of this filter you need to configure FFmpeg with
11329 @code{--enable-libvidstab}.
11331 @subsection Options
11335 Set path to the file used to read the transforms. Default value is
11336 @file{transforms.trf}.
11339 Set the number of frames (value*2 + 1) used for lowpass filtering the
11340 camera movements. Default value is 10.
11342 For example a number of 10 means that 21 frames are used (10 in the
11343 past and 10 in the future) to smoothen the motion in the video. A
11344 larger value leads to a smoother video, but limits the acceleration of
11345 the camera (pan/tilt movements). 0 is a special case where a static
11346 camera is simulated.
11349 Set the camera path optimization algorithm.
11351 Accepted values are:
11354 gaussian kernel low-pass filter on camera motion (default)
11356 averaging on transformations
11360 Set maximal number of pixels to translate frames. Default value is -1,
11364 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
11365 value is -1, meaning no limit.
11368 Specify how to deal with borders that may be visible due to movement
11371 Available values are:
11374 keep image information from previous frame (default)
11376 fill the border black
11380 Invert transforms if set to 1. Default value is 0.
11383 Consider transforms as relative to previous frame if set to 1,
11384 absolute if set to 0. Default value is 0.
11387 Set percentage to zoom. A positive value will result in a zoom-in
11388 effect, a negative value in a zoom-out effect. Default value is 0 (no
11392 Set optimal zooming to avoid borders.
11394 Accepted values are:
11399 optimal static zoom value is determined (only very strong movements
11400 will lead to visible borders) (default)
11402 optimal adaptive zoom value is determined (no borders will be
11403 visible), see @option{zoomspeed}
11406 Note that the value given at zoom is added to the one calculated here.
11409 Set percent to zoom maximally each frame (enabled when
11410 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
11414 Specify type of interpolation.
11416 Available values are:
11421 linear only horizontal
11423 linear in both directions (default)
11425 cubic in both directions (slow)
11429 Enable virtual tripod mode if set to 1, which is equivalent to
11430 @code{relative=0:smoothing=0}. Default value is 0.
11432 Use also @code{tripod} option of @ref{vidstabdetect}.
11435 Increase log verbosity if set to 1. Also the detected global motions
11436 are written to the temporary file @file{global_motions.trf}. Default
11440 @subsection Examples
11444 Use @command{ffmpeg} for a typical stabilization with default values:
11446 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
11449 Note the use of the @ref{unsharp} filter which is always recommended.
11452 Zoom in a bit more and load transform data from a given file:
11454 vidstabtransform=zoom=5:input="mytransforms.trf"
11458 Smoothen the video even more:
11460 vidstabtransform=smoothing=30
11466 Flip the input video vertically.
11468 For example, to vertically flip a video with @command{ffmpeg}:
11470 ffmpeg -i in.avi -vf "vflip" out.avi
11476 Make or reverse a natural vignetting effect.
11478 The filter accepts the following options:
11482 Set lens angle expression as a number of radians.
11484 The value is clipped in the @code{[0,PI/2]} range.
11486 Default value: @code{"PI/5"}
11490 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
11494 Set forward/backward mode.
11496 Available modes are:
11499 The larger the distance from the central point, the darker the image becomes.
11502 The larger the distance from the central point, the brighter the image becomes.
11503 This can be used to reverse a vignette effect, though there is no automatic
11504 detection to extract the lens @option{angle} and other settings (yet). It can
11505 also be used to create a burning effect.
11508 Default value is @samp{forward}.
11511 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
11513 It accepts the following values:
11516 Evaluate expressions only once during the filter initialization.
11519 Evaluate expressions for each incoming frame. This is way slower than the
11520 @samp{init} mode since it requires all the scalers to be re-computed, but it
11521 allows advanced dynamic expressions.
11524 Default value is @samp{init}.
11527 Set dithering to reduce the circular banding effects. Default is @code{1}
11531 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
11532 Setting this value to the SAR of the input will make a rectangular vignetting
11533 following the dimensions of the video.
11535 Default is @code{1/1}.
11538 @subsection Expressions
11540 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
11541 following parameters.
11546 input width and height
11549 the number of input frame, starting from 0
11552 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
11553 @var{TB} units, NAN if undefined
11556 frame rate of the input video, NAN if the input frame rate is unknown
11559 the PTS (Presentation TimeStamp) of the filtered video frame,
11560 expressed in seconds, NAN if undefined
11563 time base of the input video
11567 @subsection Examples
11571 Apply simple strong vignetting effect:
11577 Make a flickering vignetting:
11579 vignette='PI/4+random(1)*PI/50':eval=frame
11585 Stack input videos vertically.
11587 All streams must be of same pixel format and of same width.
11589 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
11590 to create same output.
11592 The filter accept the following option:
11596 Set number of input streams. Default is 2.
11601 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
11602 Deinterlacing Filter").
11604 Based on the process described by Martin Weston for BBC R&D, and
11605 implemented based on the de-interlace algorithm written by Jim
11606 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
11607 uses filter coefficients calculated by BBC R&D.
11609 There are two sets of filter coefficients, so called "simple":
11610 and "complex". Which set of filter coefficients is used can
11611 be set by passing an optional parameter:
11615 Set the interlacing filter coefficients. Accepts one of the following values:
11619 Simple filter coefficient set.
11621 More-complex filter coefficient set.
11623 Default value is @samp{complex}.
11626 Specify which frames to deinterlace. Accept one of the following values:
11630 Deinterlace all frames,
11632 Only deinterlace frames marked as interlaced.
11635 Default value is @samp{all}.
11639 Video waveform monitor.
11641 The waveform monitor plots color component intensity. By default luminance
11642 only. Each column of the waveform corresponds to a column of pixels in the
11645 It accepts the following options:
11649 Can be either @code{row}, or @code{column}. Default is @code{column}.
11650 In row mode, the graph on the left side represents color component value 0 and
11651 the right side represents value = 255. In column mode, the top side represents
11652 color component value = 0 and bottom side represents value = 255.
11655 Set intensity. Smaller values are useful to find out how many values of the same
11656 luminance are distributed across input rows/columns.
11657 Default value is @code{0.04}. Allowed range is [0, 1].
11660 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
11661 In mirrored mode, higher values will be represented on the left
11662 side for @code{row} mode and at the top for @code{column} mode. Default is
11663 @code{1} (mirrored).
11667 It accepts the following values:
11670 Presents information identical to that in the @code{parade}, except
11671 that the graphs representing color components are superimposed directly
11674 This display mode makes it easier to spot relative differences or similarities
11675 in overlapping areas of the color components that are supposed to be identical,
11676 such as neutral whites, grays, or blacks.
11679 Display separate graph for the color components side by side in
11680 @code{row} mode or one below the other in @code{column} mode.
11682 Using this display mode makes it easy to spot color casts in the highlights
11683 and shadows of an image, by comparing the contours of the top and the bottom
11684 graphs of each waveform. Since whites, grays, and blacks are characterized
11685 by exactly equal amounts of red, green, and blue, neutral areas of the picture
11686 should display three waveforms of roughly equal width/height. If not, the
11687 correction is easy to perform by making level adjustments the three waveforms.
11689 Default is @code{parade}.
11691 @item components, c
11692 Set which color components to display. Default is 1, which means only luminance
11693 or red color component if input is in RGB colorspace. If is set for example to
11694 7 it will display all 3 (if) available color components.
11699 No envelope, this is default.
11702 Instant envelope, minimum and maximum values presented in graph will be easily
11703 visible even with small @code{step} value.
11706 Hold minimum and maximum values presented in graph across time. This way you
11707 can still spot out of range values without constantly looking at waveforms.
11710 Peak and instant envelope combined together.
11716 No filtering, this is default.
11719 Luma and chroma combined together.
11722 Similar as above, but shows difference between blue and red chroma.
11725 Displays only chroma.
11728 Similar as above, but shows difference between blue and red chroma.
11731 Displays actual color value on waveform.
11736 Apply the xBR high-quality magnification filter which is designed for pixel
11737 art. It follows a set of edge-detection rules, see
11738 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
11740 It accepts the following option:
11744 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
11745 @code{3xBR} and @code{4} for @code{4xBR}.
11746 Default is @code{3}.
11752 Deinterlace the input video ("yadif" means "yet another deinterlacing
11755 It accepts the following parameters:
11761 The interlacing mode to adopt. It accepts one of the following values:
11764 @item 0, send_frame
11765 Output one frame for each frame.
11766 @item 1, send_field
11767 Output one frame for each field.
11768 @item 2, send_frame_nospatial
11769 Like @code{send_frame}, but it skips the spatial interlacing check.
11770 @item 3, send_field_nospatial
11771 Like @code{send_field}, but it skips the spatial interlacing check.
11774 The default value is @code{send_frame}.
11777 The picture field parity assumed for the input interlaced video. It accepts one
11778 of the following values:
11782 Assume the top field is first.
11784 Assume the bottom field is first.
11786 Enable automatic detection of field parity.
11789 The default value is @code{auto}.
11790 If the interlacing is unknown or the decoder does not export this information,
11791 top field first will be assumed.
11794 Specify which frames to deinterlace. Accept one of the following
11799 Deinterlace all frames.
11800 @item 1, interlaced
11801 Only deinterlace frames marked as interlaced.
11804 The default value is @code{all}.
11809 Apply Zoom & Pan effect.
11811 This filter accepts the following options:
11815 Set the zoom expression. Default is 1.
11819 Set the x and y expression. Default is 0.
11822 Set the duration expression in number of frames.
11823 This sets for how many number of frames effect will last for
11824 single input image.
11827 Set the output image size, default is 'hd720'.
11830 Each expression can contain the following constants:
11849 Output frame count.
11853 Last calculated 'x' and 'y' position from 'x' and 'y' expression
11854 for current input frame.
11858 'x' and 'y' of last output frame of previous input frame or 0 when there was
11859 not yet such frame (first input frame).
11862 Last calculated zoom from 'z' expression for current input frame.
11865 Last calculated zoom of last output frame of previous input frame.
11868 Number of output frames for current input frame. Calculated from 'd' expression
11869 for each input frame.
11872 number of output frames created for previous input frame
11875 Rational number: input width / input height
11878 sample aspect ratio
11881 display aspect ratio
11885 @subsection Examples
11889 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
11891 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='if(gte(zoom,1.5),x,x+1/a)':y='if(gte(zoom,1.5),y,y+1)':s=640x360
11895 Zoom-in up to 1.5 and pan always at center of picture:
11897 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
11902 Scale (resize) the input video, using the z.lib library:
11903 https://github.com/sekrit-twc/zimg.
11905 The zscale filter forces the output display aspect ratio to be the same
11906 as the input, by changing the output sample aspect ratio.
11908 If the input image format is different from the format requested by
11909 the next filter, the zscale filter will convert the input to the
11912 @subsection Options
11913 The filter accepts the following options.
11918 Set the output video dimension expression. Default value is the input
11921 If the @var{width} or @var{w} is 0, the input width is used for the output.
11922 If the @var{height} or @var{h} is 0, the input height is used for the output.
11924 If one of the values is -1, the zscale filter will use a value that
11925 maintains the aspect ratio of the input image, calculated from the
11926 other specified dimension. If both of them are -1, the input size is
11929 If one of the values is -n with n > 1, the zscale filter will also use a value
11930 that maintains the aspect ratio of the input image, calculated from the other
11931 specified dimension. After that it will, however, make sure that the calculated
11932 dimension is divisible by n and adjust the value if necessary.
11934 See below for the list of accepted constants for use in the dimension
11938 Set the video size. For the syntax of this option, check the
11939 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11942 Set the dither type.
11944 Possible values are:
11949 @item error_diffusion
11955 Set the resize filter type.
11957 Possible values are:
11967 Default is bilinear.
11970 Set the color range.
11972 Possible values are:
11979 Default is same as input.
11982 Set the color primaries.
11984 Possible values are:
11994 Default is same as input.
11997 Set the transfer characteristics.
11999 Possible values are:
12010 Default is same as input.
12013 Set the colorspace matrix.
12015 Possible value are:
12026 Default is same as input.
12029 The values of the @option{w} and @option{h} options are expressions
12030 containing the following constants:
12035 The input width and height
12039 These are the same as @var{in_w} and @var{in_h}.
12043 The output (scaled) width and height
12047 These are the same as @var{out_w} and @var{out_h}
12050 The same as @var{iw} / @var{ih}
12053 input sample aspect ratio
12056 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
12060 horizontal and vertical input chroma subsample values. For example for the
12061 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
12065 horizontal and vertical output chroma subsample values. For example for the
12066 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
12072 @c man end VIDEO FILTERS
12074 @chapter Video Sources
12075 @c man begin VIDEO SOURCES
12077 Below is a description of the currently available video sources.
12081 Buffer video frames, and make them available to the filter chain.
12083 This source is mainly intended for a programmatic use, in particular
12084 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
12086 It accepts the following parameters:
12091 Specify the size (width and height) of the buffered video frames. For the
12092 syntax of this option, check the
12093 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12096 The input video width.
12099 The input video height.
12102 A string representing the pixel format of the buffered video frames.
12103 It may be a number corresponding to a pixel format, or a pixel format
12107 Specify the timebase assumed by the timestamps of the buffered frames.
12110 Specify the frame rate expected for the video stream.
12112 @item pixel_aspect, sar
12113 The sample (pixel) aspect ratio of the input video.
12116 Specify the optional parameters to be used for the scale filter which
12117 is automatically inserted when an input change is detected in the
12118 input size or format.
12123 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
12126 will instruct the source to accept video frames with size 320x240 and
12127 with format "yuv410p", assuming 1/24 as the timestamps timebase and
12128 square pixels (1:1 sample aspect ratio).
12129 Since the pixel format with name "yuv410p" corresponds to the number 6
12130 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
12131 this example corresponds to:
12133 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
12136 Alternatively, the options can be specified as a flat string, but this
12137 syntax is deprecated:
12139 @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}]
12143 Create a pattern generated by an elementary cellular automaton.
12145 The initial state of the cellular automaton can be defined through the
12146 @option{filename}, and @option{pattern} options. If such options are
12147 not specified an initial state is created randomly.
12149 At each new frame a new row in the video is filled with the result of
12150 the cellular automaton next generation. The behavior when the whole
12151 frame is filled is defined by the @option{scroll} option.
12153 This source accepts the following options:
12157 Read the initial cellular automaton state, i.e. the starting row, from
12158 the specified file.
12159 In the file, each non-whitespace character is considered an alive
12160 cell, a newline will terminate the row, and further characters in the
12161 file will be ignored.
12164 Read the initial cellular automaton state, i.e. the starting row, from
12165 the specified string.
12167 Each non-whitespace character in the string is considered an alive
12168 cell, a newline will terminate the row, and further characters in the
12169 string will be ignored.
12172 Set the video rate, that is the number of frames generated per second.
12175 @item random_fill_ratio, ratio
12176 Set the random fill ratio for the initial cellular automaton row. It
12177 is a floating point number value ranging from 0 to 1, defaults to
12180 This option is ignored when a file or a pattern is specified.
12182 @item random_seed, seed
12183 Set the seed for filling randomly the initial row, must be an integer
12184 included between 0 and UINT32_MAX. If not specified, or if explicitly
12185 set to -1, the filter will try to use a good random seed on a best
12189 Set the cellular automaton rule, it is a number ranging from 0 to 255.
12190 Default value is 110.
12193 Set the size of the output video. For the syntax of this option, check the
12194 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12196 If @option{filename} or @option{pattern} is specified, the size is set
12197 by default to the width of the specified initial state row, and the
12198 height is set to @var{width} * PHI.
12200 If @option{size} is set, it must contain the width of the specified
12201 pattern string, and the specified pattern will be centered in the
12204 If a filename or a pattern string is not specified, the size value
12205 defaults to "320x518" (used for a randomly generated initial state).
12208 If set to 1, scroll the output upward when all the rows in the output
12209 have been already filled. If set to 0, the new generated row will be
12210 written over the top row just after the bottom row is filled.
12213 @item start_full, full
12214 If set to 1, completely fill the output with generated rows before
12215 outputting the first frame.
12216 This is the default behavior, for disabling set the value to 0.
12219 If set to 1, stitch the left and right row edges together.
12220 This is the default behavior, for disabling set the value to 0.
12223 @subsection Examples
12227 Read the initial state from @file{pattern}, and specify an output of
12230 cellauto=f=pattern:s=200x400
12234 Generate a random initial row with a width of 200 cells, with a fill
12237 cellauto=ratio=2/3:s=200x200
12241 Create a pattern generated by rule 18 starting by a single alive cell
12242 centered on an initial row with width 100:
12244 cellauto=p=@@:s=100x400:full=0:rule=18
12248 Specify a more elaborated initial pattern:
12250 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
12255 @section mandelbrot
12257 Generate a Mandelbrot set fractal, and progressively zoom towards the
12258 point specified with @var{start_x} and @var{start_y}.
12260 This source accepts the following options:
12265 Set the terminal pts value. Default value is 400.
12268 Set the terminal scale value.
12269 Must be a floating point value. Default value is 0.3.
12272 Set the inner coloring mode, that is the algorithm used to draw the
12273 Mandelbrot fractal internal region.
12275 It shall assume one of the following values:
12280 Show time until convergence.
12282 Set color based on point closest to the origin of the iterations.
12287 Default value is @var{mincol}.
12290 Set the bailout value. Default value is 10.0.
12293 Set the maximum of iterations performed by the rendering
12294 algorithm. Default value is 7189.
12297 Set outer coloring mode.
12298 It shall assume one of following values:
12300 @item iteration_count
12301 Set iteration cound mode.
12302 @item normalized_iteration_count
12303 set normalized iteration count mode.
12305 Default value is @var{normalized_iteration_count}.
12308 Set frame rate, expressed as number of frames per second. Default
12312 Set frame size. For the syntax of this option, check the "Video
12313 size" section in the ffmpeg-utils manual. Default value is "640x480".
12316 Set the initial scale value. Default value is 3.0.
12319 Set the initial x position. Must be a floating point value between
12320 -100 and 100. Default value is -0.743643887037158704752191506114774.
12323 Set the initial y position. Must be a floating point value between
12324 -100 and 100. Default value is -0.131825904205311970493132056385139.
12329 Generate various test patterns, as generated by the MPlayer test filter.
12331 The size of the generated video is fixed, and is 256x256.
12332 This source is useful in particular for testing encoding features.
12334 This source accepts the following options:
12339 Specify the frame rate of the sourced video, as the number of frames
12340 generated per second. It has to be a string in the format
12341 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
12342 number or a valid video frame rate abbreviation. The default value is
12346 Set the duration of the sourced video. See
12347 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
12348 for the accepted syntax.
12350 If not specified, or the expressed duration is negative, the video is
12351 supposed to be generated forever.
12355 Set the number or the name of the test to perform. Supported tests are:
12371 Default value is "all", which will cycle through the list of all tests.
12376 mptestsrc=t=dc_luma
12379 will generate a "dc_luma" test pattern.
12381 @section frei0r_src
12383 Provide a frei0r source.
12385 To enable compilation of this filter you need to install the frei0r
12386 header and configure FFmpeg with @code{--enable-frei0r}.
12388 This source accepts the following parameters:
12393 The size of the video to generate. For the syntax of this option, check the
12394 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12397 The framerate of the generated video. It may be a string of the form
12398 @var{num}/@var{den} or a frame rate abbreviation.
12401 The name to the frei0r source to load. For more information regarding frei0r and
12402 how to set the parameters, read the @ref{frei0r} section in the video filters
12405 @item filter_params
12406 A '|'-separated list of parameters to pass to the frei0r source.
12410 For example, to generate a frei0r partik0l source with size 200x200
12411 and frame rate 10 which is overlaid on the overlay filter main input:
12413 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
12418 Generate a life pattern.
12420 This source is based on a generalization of John Conway's life game.
12422 The sourced input represents a life grid, each pixel represents a cell
12423 which can be in one of two possible states, alive or dead. Every cell
12424 interacts with its eight neighbours, which are the cells that are
12425 horizontally, vertically, or diagonally adjacent.
12427 At each interaction the grid evolves according to the adopted rule,
12428 which specifies the number of neighbor alive cells which will make a
12429 cell stay alive or born. The @option{rule} option allows one to specify
12432 This source accepts the following options:
12436 Set the file from which to read the initial grid state. In the file,
12437 each non-whitespace character is considered an alive cell, and newline
12438 is used to delimit the end of each row.
12440 If this option is not specified, the initial grid is generated
12444 Set the video rate, that is the number of frames generated per second.
12447 @item random_fill_ratio, ratio
12448 Set the random fill ratio for the initial random grid. It is a
12449 floating point number value ranging from 0 to 1, defaults to 1/PHI.
12450 It is ignored when a file is specified.
12452 @item random_seed, seed
12453 Set the seed for filling the initial random grid, must be an integer
12454 included between 0 and UINT32_MAX. If not specified, or if explicitly
12455 set to -1, the filter will try to use a good random seed on a best
12461 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
12462 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
12463 @var{NS} specifies the number of alive neighbor cells which make a
12464 live cell stay alive, and @var{NB} the number of alive neighbor cells
12465 which make a dead cell to become alive (i.e. to "born").
12466 "s" and "b" can be used in place of "S" and "B", respectively.
12468 Alternatively a rule can be specified by an 18-bits integer. The 9
12469 high order bits are used to encode the next cell state if it is alive
12470 for each number of neighbor alive cells, the low order bits specify
12471 the rule for "borning" new cells. Higher order bits encode for an
12472 higher number of neighbor cells.
12473 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
12474 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
12476 Default value is "S23/B3", which is the original Conway's game of life
12477 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
12478 cells, and will born a new cell if there are three alive cells around
12482 Set the size of the output video. For the syntax of this option, check the
12483 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12485 If @option{filename} is specified, the size is set by default to the
12486 same size of the input file. If @option{size} is set, it must contain
12487 the size specified in the input file, and the initial grid defined in
12488 that file is centered in the larger resulting area.
12490 If a filename is not specified, the size value defaults to "320x240"
12491 (used for a randomly generated initial grid).
12494 If set to 1, stitch the left and right grid edges together, and the
12495 top and bottom edges also. Defaults to 1.
12498 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
12499 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
12500 value from 0 to 255.
12503 Set the color of living (or new born) cells.
12506 Set the color of dead cells. If @option{mold} is set, this is the first color
12507 used to represent a dead cell.
12510 Set mold color, for definitely dead and moldy cells.
12512 For the syntax of these 3 color options, check the "Color" section in the
12513 ffmpeg-utils manual.
12516 @subsection Examples
12520 Read a grid from @file{pattern}, and center it on a grid of size
12523 life=f=pattern:s=300x300
12527 Generate a random grid of size 200x200, with a fill ratio of 2/3:
12529 life=ratio=2/3:s=200x200
12533 Specify a custom rule for evolving a randomly generated grid:
12539 Full example with slow death effect (mold) using @command{ffplay}:
12541 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
12548 @anchor{haldclutsrc}
12550 @anchor{rgbtestsrc}
12552 @anchor{smptehdbars}
12554 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
12556 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
12558 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
12560 The @code{color} source provides an uniformly colored input.
12562 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
12563 @ref{haldclut} filter.
12565 The @code{nullsrc} source returns unprocessed video frames. It is
12566 mainly useful to be employed in analysis / debugging tools, or as the
12567 source for filters which ignore the input data.
12569 The @code{rgbtestsrc} source generates an RGB test pattern useful for
12570 detecting RGB vs BGR issues. You should see a red, green and blue
12571 stripe from top to bottom.
12573 The @code{smptebars} source generates a color bars pattern, based on
12574 the SMPTE Engineering Guideline EG 1-1990.
12576 The @code{smptehdbars} source generates a color bars pattern, based on
12577 the SMPTE RP 219-2002.
12579 The @code{testsrc} source generates a test video pattern, showing a
12580 color pattern, a scrolling gradient and a timestamp. This is mainly
12581 intended for testing purposes.
12583 The sources accept the following parameters:
12588 Specify the color of the source, only available in the @code{color}
12589 source. For the syntax of this option, check the "Color" section in the
12590 ffmpeg-utils manual.
12593 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
12594 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
12595 pixels to be used as identity matrix for 3D lookup tables. Each component is
12596 coded on a @code{1/(N*N)} scale.
12599 Specify the size of the sourced video. For the syntax of this option, check the
12600 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12601 The default value is @code{320x240}.
12603 This option is not available with the @code{haldclutsrc} filter.
12606 Specify the frame rate of the sourced video, as the number of frames
12607 generated per second. It has to be a string in the format
12608 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
12609 number or a valid video frame rate abbreviation. The default value is
12613 Set the sample aspect ratio of the sourced video.
12616 Set the duration of the sourced video. See
12617 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
12618 for the accepted syntax.
12620 If not specified, or the expressed duration is negative, the video is
12621 supposed to be generated forever.
12624 Set the number of decimals to show in the timestamp, only available in the
12625 @code{testsrc} source.
12627 The displayed timestamp value will correspond to the original
12628 timestamp value multiplied by the power of 10 of the specified
12629 value. Default value is 0.
12632 For example the following:
12634 testsrc=duration=5.3:size=qcif:rate=10
12637 will generate a video with a duration of 5.3 seconds, with size
12638 176x144 and a frame rate of 10 frames per second.
12640 The following graph description will generate a red source
12641 with an opacity of 0.2, with size "qcif" and a frame rate of 10
12644 color=c=red@@0.2:s=qcif:r=10
12647 If the input content is to be ignored, @code{nullsrc} can be used. The
12648 following command generates noise in the luminance plane by employing
12649 the @code{geq} filter:
12651 nullsrc=s=256x256, geq=random(1)*255:128:128
12654 @subsection Commands
12656 The @code{color} source supports the following commands:
12660 Set the color of the created image. Accepts the same syntax of the
12661 corresponding @option{color} option.
12664 @c man end VIDEO SOURCES
12666 @chapter Video Sinks
12667 @c man begin VIDEO SINKS
12669 Below is a description of the currently available video sinks.
12671 @section buffersink
12673 Buffer video frames, and make them available to the end of the filter
12676 This sink is mainly intended for programmatic use, in particular
12677 through the interface defined in @file{libavfilter/buffersink.h}
12678 or the options system.
12680 It accepts a pointer to an AVBufferSinkContext structure, which
12681 defines the incoming buffers' formats, to be passed as the opaque
12682 parameter to @code{avfilter_init_filter} for initialization.
12686 Null video sink: do absolutely nothing with the input video. It is
12687 mainly useful as a template and for use in analysis / debugging
12690 @c man end VIDEO SINKS
12692 @chapter Multimedia Filters
12693 @c man begin MULTIMEDIA FILTERS
12695 Below is a description of the currently available multimedia filters.
12697 @section aphasemeter
12699 Convert input audio to a video output, displaying the audio phase.
12701 The filter accepts the following options:
12705 Set the output frame rate. Default value is @code{25}.
12708 Set the video size for the output. For the syntax of this option, check the
12709 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12710 Default value is @code{800x400}.
12715 Specify the red, green, blue contrast. Default values are @code{2},
12716 @code{7} and @code{1}.
12717 Allowed range is @code{[0, 255]}.
12720 Set color which will be used for drawing median phase. If color is
12721 @code{none} which is default, no median phase value will be drawn.
12724 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
12725 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
12726 The @code{-1} means left and right channels are completely out of phase and
12727 @code{1} means channels are in phase.
12729 @section avectorscope
12731 Convert input audio to a video output, representing the audio vector
12734 The filter is used to measure the difference between channels of stereo
12735 audio stream. A monoaural signal, consisting of identical left and right
12736 signal, results in straight vertical line. Any stereo separation is visible
12737 as a deviation from this line, creating a Lissajous figure.
12738 If the straight (or deviation from it) but horizontal line appears this
12739 indicates that the left and right channels are out of phase.
12741 The filter accepts the following options:
12745 Set the vectorscope mode.
12747 Available values are:
12750 Lissajous rotated by 45 degrees.
12753 Same as above but not rotated.
12756 Shape resembling half of circle.
12759 Default value is @samp{lissajous}.
12762 Set the video size for the output. For the syntax of this option, check the
12763 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12764 Default value is @code{400x400}.
12767 Set the output frame rate. Default value is @code{25}.
12773 Specify the red, green, blue and alpha contrast. Default values are @code{40},
12774 @code{160}, @code{80} and @code{255}.
12775 Allowed range is @code{[0, 255]}.
12781 Specify the red, green, blue and alpha fade. Default values are @code{15},
12782 @code{10}, @code{5} and @code{5}.
12783 Allowed range is @code{[0, 255]}.
12786 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
12789 @subsection Examples
12793 Complete example using @command{ffplay}:
12795 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
12796 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
12802 Concatenate audio and video streams, joining them together one after the
12805 The filter works on segments of synchronized video and audio streams. All
12806 segments must have the same number of streams of each type, and that will
12807 also be the number of streams at output.
12809 The filter accepts the following options:
12814 Set the number of segments. Default is 2.
12817 Set the number of output video streams, that is also the number of video
12818 streams in each segment. Default is 1.
12821 Set the number of output audio streams, that is also the number of audio
12822 streams in each segment. Default is 0.
12825 Activate unsafe mode: do not fail if segments have a different format.
12829 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
12830 @var{a} audio outputs.
12832 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
12833 segment, in the same order as the outputs, then the inputs for the second
12836 Related streams do not always have exactly the same duration, for various
12837 reasons including codec frame size or sloppy authoring. For that reason,
12838 related synchronized streams (e.g. a video and its audio track) should be
12839 concatenated at once. The concat filter will use the duration of the longest
12840 stream in each segment (except the last one), and if necessary pad shorter
12841 audio streams with silence.
12843 For this filter to work correctly, all segments must start at timestamp 0.
12845 All corresponding streams must have the same parameters in all segments; the
12846 filtering system will automatically select a common pixel format for video
12847 streams, and a common sample format, sample rate and channel layout for
12848 audio streams, but other settings, such as resolution, must be converted
12849 explicitly by the user.
12851 Different frame rates are acceptable but will result in variable frame rate
12852 at output; be sure to configure the output file to handle it.
12854 @subsection Examples
12858 Concatenate an opening, an episode and an ending, all in bilingual version
12859 (video in stream 0, audio in streams 1 and 2):
12861 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
12862 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
12863 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
12864 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
12868 Concatenate two parts, handling audio and video separately, using the
12869 (a)movie sources, and adjusting the resolution:
12871 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
12872 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
12873 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
12875 Note that a desync will happen at the stitch if the audio and video streams
12876 do not have exactly the same duration in the first file.
12883 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
12884 it unchanged. By default, it logs a message at a frequency of 10Hz with the
12885 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
12886 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
12888 The filter also has a video output (see the @var{video} option) with a real
12889 time graph to observe the loudness evolution. The graphic contains the logged
12890 message mentioned above, so it is not printed anymore when this option is set,
12891 unless the verbose logging is set. The main graphing area contains the
12892 short-term loudness (3 seconds of analysis), and the gauge on the right is for
12893 the momentary loudness (400 milliseconds).
12895 More information about the Loudness Recommendation EBU R128 on
12896 @url{http://tech.ebu.ch/loudness}.
12898 The filter accepts the following options:
12903 Activate the video output. The audio stream is passed unchanged whether this
12904 option is set or no. The video stream will be the first output stream if
12905 activated. Default is @code{0}.
12908 Set the video size. This option is for video only. For the syntax of this
12910 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12911 Default and minimum resolution is @code{640x480}.
12914 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
12915 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
12916 other integer value between this range is allowed.
12919 Set metadata injection. If set to @code{1}, the audio input will be segmented
12920 into 100ms output frames, each of them containing various loudness information
12921 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
12923 Default is @code{0}.
12926 Force the frame logging level.
12928 Available values are:
12931 information logging level
12933 verbose logging level
12936 By default, the logging level is set to @var{info}. If the @option{video} or
12937 the @option{metadata} options are set, it switches to @var{verbose}.
12942 Available modes can be cumulated (the option is a @code{flag} type). Possible
12946 Disable any peak mode (default).
12948 Enable sample-peak mode.
12950 Simple peak mode looking for the higher sample value. It logs a message
12951 for sample-peak (identified by @code{SPK}).
12953 Enable true-peak mode.
12955 If enabled, the peak lookup is done on an over-sampled version of the input
12956 stream for better peak accuracy. It logs a message for true-peak.
12957 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
12958 This mode requires a build with @code{libswresample}.
12962 Treat mono input files as "dual mono". If a mono file is intended for playback
12963 on a stereo system, its EBU R128 measurement will be perceptually incorrect.
12964 If set to @code{true}, this option will compensate for this effect.
12965 Multi-channel input files are not affected by this option.
12968 Set a specific pan law to be used for the measurement of dual mono files.
12969 This parameter is optional, and has a default value of -3.01dB.
12972 @subsection Examples
12976 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
12978 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
12982 Run an analysis with @command{ffmpeg}:
12984 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
12988 @section interleave, ainterleave
12990 Temporally interleave frames from several inputs.
12992 @code{interleave} works with video inputs, @code{ainterleave} with audio.
12994 These filters read frames from several inputs and send the oldest
12995 queued frame to the output.
12997 Input streams must have a well defined, monotonically increasing frame
13000 In order to submit one frame to output, these filters need to enqueue
13001 at least one frame for each input, so they cannot work in case one
13002 input is not yet terminated and will not receive incoming frames.
13004 For example consider the case when one input is a @code{select} filter
13005 which always drop input frames. The @code{interleave} filter will keep
13006 reading from that input, but it will never be able to send new frames
13007 to output until the input will send an end-of-stream signal.
13009 Also, depending on inputs synchronization, the filters will drop
13010 frames in case one input receives more frames than the other ones, and
13011 the queue is already filled.
13013 These filters accept the following options:
13017 Set the number of different inputs, it is 2 by default.
13020 @subsection Examples
13024 Interleave frames belonging to different streams using @command{ffmpeg}:
13026 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
13030 Add flickering blur effect:
13032 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
13036 @section perms, aperms
13038 Set read/write permissions for the output frames.
13040 These filters are mainly aimed at developers to test direct path in the
13041 following filter in the filtergraph.
13043 The filters accept the following options:
13047 Select the permissions mode.
13049 It accepts the following values:
13052 Do nothing. This is the default.
13054 Set all the output frames read-only.
13056 Set all the output frames directly writable.
13058 Make the frame read-only if writable, and writable if read-only.
13060 Set each output frame read-only or writable randomly.
13064 Set the seed for the @var{random} mode, must be an integer included between
13065 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
13066 @code{-1}, the filter will try to use a good random seed on a best effort
13070 Note: in case of auto-inserted filter between the permission filter and the
13071 following one, the permission might not be received as expected in that
13072 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
13073 perms/aperms filter can avoid this problem.
13075 @section realtime, arealtime
13077 Slow down filtering to match real time approximatively.
13079 These filters will pause the filtering for a variable amount of time to
13080 match the output rate with the input timestamps.
13081 They are similar to the @option{re} option to @code{ffmpeg}.
13083 They accept the following options:
13087 Time limit for the pauses. Any pause longer than that will be considered
13088 a timestamp discontinuity and reset the timer. Default is 2 seconds.
13091 @section select, aselect
13093 Select frames to pass in output.
13095 This filter accepts the following options:
13100 Set expression, which is evaluated for each input frame.
13102 If the expression is evaluated to zero, the frame is discarded.
13104 If the evaluation result is negative or NaN, the frame is sent to the
13105 first output; otherwise it is sent to the output with index
13106 @code{ceil(val)-1}, assuming that the input index starts from 0.
13108 For example a value of @code{1.2} corresponds to the output with index
13109 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
13112 Set the number of outputs. The output to which to send the selected
13113 frame is based on the result of the evaluation. Default value is 1.
13116 The expression can contain the following constants:
13120 The (sequential) number of the filtered frame, starting from 0.
13123 The (sequential) number of the selected frame, starting from 0.
13125 @item prev_selected_n
13126 The sequential number of the last selected frame. It's NAN if undefined.
13129 The timebase of the input timestamps.
13132 The PTS (Presentation TimeStamp) of the filtered video frame,
13133 expressed in @var{TB} units. It's NAN if undefined.
13136 The PTS of the filtered video frame,
13137 expressed in seconds. It's NAN if undefined.
13140 The PTS of the previously filtered video frame. It's NAN if undefined.
13142 @item prev_selected_pts
13143 The PTS of the last previously filtered video frame. It's NAN if undefined.
13145 @item prev_selected_t
13146 The PTS of the last previously selected video frame. It's NAN if undefined.
13149 The PTS of the first video frame in the video. It's NAN if undefined.
13152 The time of the first video frame in the video. It's NAN if undefined.
13154 @item pict_type @emph{(video only)}
13155 The type of the filtered frame. It can assume one of the following
13167 @item interlace_type @emph{(video only)}
13168 The frame interlace type. It can assume one of the following values:
13171 The frame is progressive (not interlaced).
13173 The frame is top-field-first.
13175 The frame is bottom-field-first.
13178 @item consumed_sample_n @emph{(audio only)}
13179 the number of selected samples before the current frame
13181 @item samples_n @emph{(audio only)}
13182 the number of samples in the current frame
13184 @item sample_rate @emph{(audio only)}
13185 the input sample rate
13188 This is 1 if the filtered frame is a key-frame, 0 otherwise.
13191 the position in the file of the filtered frame, -1 if the information
13192 is not available (e.g. for synthetic video)
13194 @item scene @emph{(video only)}
13195 value between 0 and 1 to indicate a new scene; a low value reflects a low
13196 probability for the current frame to introduce a new scene, while a higher
13197 value means the current frame is more likely to be one (see the example below)
13201 The default value of the select expression is "1".
13203 @subsection Examples
13207 Select all frames in input:
13212 The example above is the same as:
13224 Select only I-frames:
13226 select='eq(pict_type\,I)'
13230 Select one frame every 100:
13232 select='not(mod(n\,100))'
13236 Select only frames contained in the 10-20 time interval:
13238 select=between(t\,10\,20)
13242 Select only I frames contained in the 10-20 time interval:
13244 select=between(t\,10\,20)*eq(pict_type\,I)
13248 Select frames with a minimum distance of 10 seconds:
13250 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
13254 Use aselect to select only audio frames with samples number > 100:
13256 aselect='gt(samples_n\,100)'
13260 Create a mosaic of the first scenes:
13262 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
13265 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
13269 Send even and odd frames to separate outputs, and compose them:
13271 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
13275 @section selectivecolor
13277 Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such
13278 as "reds", "yellows", "greens", "cyans", ...). The adjustment range is defined
13279 by the "purity" of the color (that is, how saturated it already is).
13281 This filter is similar to the Adobe Photoshop Selective Color tool.
13283 The filter accepts the following options:
13286 @item correction_method
13287 Select color correction method.
13289 Available values are:
13292 Specified adjustments are applied "as-is" (added/subtracted to original pixel
13295 Specified adjustments are relative to the original component value.
13297 Default is @code{absolute}.
13299 Adjustments for red pixels (pixels where the red component is the maximum)
13301 Adjustments for yellow pixels (pixels where the blue component is the minimum)
13303 Adjustments for green pixels (pixels where the green component is the maximum)
13305 Adjustments for cyan pixels (pixels where the red component is the minimum)
13307 Adjustments for blue pixels (pixels where the blue component is the maximum)
13309 Adjustments for magenta pixels (pixels where the green component is the minimum)
13311 Adjustments for white pixels (pixels where all components are greater than 128)
13313 Adjustments for all pixels except pure black and pure white
13315 Adjustments for black pixels (pixels where all components are lesser than 128)
13317 Specify a Photoshop selective color file (@code{.asv}) to import the settings from.
13320 All the adjustment settings (@option{reds}, @option{yellows}, ...) accept up to
13321 4 space separated floating point adjustment values in the [-1,1] range,
13322 respectively to adjust the amount of cyan, magenta, yellow and black for the
13323 pixels of its range.
13325 @subsection Examples
13329 Increase cyan by 50% and reduce yellow by 33% in every green areas, and
13330 increase magenta by 27% in blue areas:
13332 selectivecolor=greens=.5 0 -.33 0:blues=0 .27
13336 Use a Photoshop selective color preset:
13338 selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
13342 @section sendcmd, asendcmd
13344 Send commands to filters in the filtergraph.
13346 These filters read commands to be sent to other filters in the
13349 @code{sendcmd} must be inserted between two video filters,
13350 @code{asendcmd} must be inserted between two audio filters, but apart
13351 from that they act the same way.
13353 The specification of commands can be provided in the filter arguments
13354 with the @var{commands} option, or in a file specified by the
13355 @var{filename} option.
13357 These filters accept the following options:
13360 Set the commands to be read and sent to the other filters.
13362 Set the filename of the commands to be read and sent to the other
13366 @subsection Commands syntax
13368 A commands description consists of a sequence of interval
13369 specifications, comprising a list of commands to be executed when a
13370 particular event related to that interval occurs. The occurring event
13371 is typically the current frame time entering or leaving a given time
13374 An interval is specified by the following syntax:
13376 @var{START}[-@var{END}] @var{COMMANDS};
13379 The time interval is specified by the @var{START} and @var{END} times.
13380 @var{END} is optional and defaults to the maximum time.
13382 The current frame time is considered within the specified interval if
13383 it is included in the interval [@var{START}, @var{END}), that is when
13384 the time is greater or equal to @var{START} and is lesser than
13387 @var{COMMANDS} consists of a sequence of one or more command
13388 specifications, separated by ",", relating to that interval. The
13389 syntax of a command specification is given by:
13391 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
13394 @var{FLAGS} is optional and specifies the type of events relating to
13395 the time interval which enable sending the specified command, and must
13396 be a non-null sequence of identifier flags separated by "+" or "|" and
13397 enclosed between "[" and "]".
13399 The following flags are recognized:
13402 The command is sent when the current frame timestamp enters the
13403 specified interval. In other words, the command is sent when the
13404 previous frame timestamp was not in the given interval, and the
13408 The command is sent when the current frame timestamp leaves the
13409 specified interval. In other words, the command is sent when the
13410 previous frame timestamp was in the given interval, and the
13414 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
13417 @var{TARGET} specifies the target of the command, usually the name of
13418 the filter class or a specific filter instance name.
13420 @var{COMMAND} specifies the name of the command for the target filter.
13422 @var{ARG} is optional and specifies the optional list of argument for
13423 the given @var{COMMAND}.
13425 Between one interval specification and another, whitespaces, or
13426 sequences of characters starting with @code{#} until the end of line,
13427 are ignored and can be used to annotate comments.
13429 A simplified BNF description of the commands specification syntax
13432 @var{COMMAND_FLAG} ::= "enter" | "leave"
13433 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
13434 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
13435 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
13436 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
13437 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
13440 @subsection Examples
13444 Specify audio tempo change at second 4:
13446 asendcmd=c='4.0 atempo tempo 1.5',atempo
13450 Specify a list of drawtext and hue commands in a file.
13452 # show text in the interval 5-10
13453 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
13454 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
13456 # desaturate the image in the interval 15-20
13457 15.0-20.0 [enter] hue s 0,
13458 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
13460 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
13462 # apply an exponential saturation fade-out effect, starting from time 25
13463 25 [enter] hue s exp(25-t)
13466 A filtergraph allowing to read and process the above command list
13467 stored in a file @file{test.cmd}, can be specified with:
13469 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
13474 @section setpts, asetpts
13476 Change the PTS (presentation timestamp) of the input frames.
13478 @code{setpts} works on video frames, @code{asetpts} on audio frames.
13480 This filter accepts the following options:
13485 The expression which is evaluated for each frame to construct its timestamp.
13489 The expression is evaluated through the eval API and can contain the following
13494 frame rate, only defined for constant frame-rate video
13497 The presentation timestamp in input
13500 The count of the input frame for video or the number of consumed samples,
13501 not including the current frame for audio, starting from 0.
13503 @item NB_CONSUMED_SAMPLES
13504 The number of consumed samples, not including the current frame (only
13507 @item NB_SAMPLES, S
13508 The number of samples in the current frame (only audio)
13510 @item SAMPLE_RATE, SR
13511 The audio sample rate.
13514 The PTS of the first frame.
13517 the time in seconds of the first frame
13520 State whether the current frame is interlaced.
13523 the time in seconds of the current frame
13526 original position in the file of the frame, or undefined if undefined
13527 for the current frame
13530 The previous input PTS.
13533 previous input time in seconds
13536 The previous output PTS.
13539 previous output time in seconds
13542 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
13546 The wallclock (RTC) time at the start of the movie in microseconds.
13549 The timebase of the input timestamps.
13553 @subsection Examples
13557 Start counting PTS from zero
13559 setpts=PTS-STARTPTS
13563 Apply fast motion effect:
13569 Apply slow motion effect:
13575 Set fixed rate of 25 frames per second:
13581 Set fixed rate 25 fps with some jitter:
13583 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
13587 Apply an offset of 10 seconds to the input PTS:
13593 Generate timestamps from a "live source" and rebase onto the current timebase:
13595 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
13599 Generate timestamps by counting samples:
13606 @section settb, asettb
13608 Set the timebase to use for the output frames timestamps.
13609 It is mainly useful for testing timebase configuration.
13611 It accepts the following parameters:
13616 The expression which is evaluated into the output timebase.
13620 The value for @option{tb} is an arithmetic expression representing a
13621 rational. The expression can contain the constants "AVTB" (the default
13622 timebase), "intb" (the input timebase) and "sr" (the sample rate,
13623 audio only). Default value is "intb".
13625 @subsection Examples
13629 Set the timebase to 1/25:
13635 Set the timebase to 1/10:
13641 Set the timebase to 1001/1000:
13647 Set the timebase to 2*intb:
13653 Set the default timebase value:
13660 Convert input audio to a video output representing frequency spectrum
13661 logarithmically using Brown-Puckette constant Q transform algorithm with
13662 direct frequency domain coefficient calculation (but the transform itself
13663 is not really constant Q, instead the Q factor is actually variable/clamped),
13664 with musical tone scale, from E0 to D#10.
13666 The filter accepts the following options:
13670 Specify the video size for the output. It must be even. For the syntax of this option,
13671 check the @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13672 Default value is @code{1920x1080}.
13675 Set the output frame rate. Default value is @code{25}.
13678 Set the bargraph height. It must be even. Default value is @code{-1} which
13679 computes the bargraph height automatically.
13682 Set the axis height. It must be even. Default value is @code{-1} which computes
13683 the axis height automatically.
13686 Set the sonogram height. It must be even. Default value is @code{-1} which
13687 computes the sonogram height automatically.
13690 Set the fullhd resolution. This option is deprecated, use @var{size}, @var{s}
13691 instead. Default value is @code{1}.
13693 @item sono_v, volume
13694 Specify the sonogram volume expression. It can contain variables:
13697 the @var{bar_v} evaluated expression
13698 @item frequency, freq, f
13699 the frequency where it is evaluated
13700 @item timeclamp, tc
13701 the value of @var{timeclamp} option
13705 @item a_weighting(f)
13706 A-weighting of equal loudness
13707 @item b_weighting(f)
13708 B-weighting of equal loudness
13709 @item c_weighting(f)
13710 C-weighting of equal loudness.
13712 Default value is @code{16}.
13714 @item bar_v, volume2
13715 Specify the bargraph volume expression. It can contain variables:
13718 the @var{sono_v} evaluated expression
13719 @item frequency, freq, f
13720 the frequency where it is evaluated
13721 @item timeclamp, tc
13722 the value of @var{timeclamp} option
13726 @item a_weighting(f)
13727 A-weighting of equal loudness
13728 @item b_weighting(f)
13729 B-weighting of equal loudness
13730 @item c_weighting(f)
13731 C-weighting of equal loudness.
13733 Default value is @code{sono_v}.
13735 @item sono_g, gamma
13736 Specify the sonogram gamma. Lower gamma makes the spectrum more contrast,
13737 higher gamma makes the spectrum having more range. Default value is @code{3}.
13738 Acceptable range is @code{[1, 7]}.
13740 @item bar_g, gamma2
13741 Specify the bargraph gamma. Default value is @code{1}. Acceptable range is
13744 @item timeclamp, tc
13745 Specify the transform timeclamp. At low frequency, there is trade-off between
13746 accuracy in time domain and frequency domain. If timeclamp is lower,
13747 event in time domain is represented more accurately (such as fast bass drum),
13748 otherwise event in frequency domain is represented more accurately
13749 (such as bass guitar). Acceptable range is @code{[0.1, 1]}. Default value is @code{0.17}.
13752 Specify the transform base frequency. Default value is @code{20.01523126408007475},
13753 which is frequency 50 cents below E0. Acceptable range is @code{[10, 100000]}.
13756 Specify the transform end frequency. Default value is @code{20495.59681441799654},
13757 which is frequency 50 cents above D#10. Acceptable range is @code{[10, 100000]}.
13760 This option is deprecated and ignored.
13763 Specify the transform length in time domain. Use this option to control accuracy
13764 trade-off between time domain and frequency domain at every frequency sample.
13765 It can contain variables:
13767 @item frequency, freq, f
13768 the frequency where it is evaluated
13769 @item timeclamp, tc
13770 the value of @var{timeclamp} option.
13772 Default value is @code{384*tc/(384+tc*f)}.
13775 Specify the transform count for every video frame. Default value is @code{6}.
13776 Acceptable range is @code{[1, 30]}.
13779 Specify the transform count for every single pixel. Default value is @code{0},
13780 which makes it computed automatically. Acceptable range is @code{[0, 10]}.
13783 Specify font file for use with freetype to draw the axis. If not specified,
13784 use embedded font. Note that drawing with font file or embedded font is not
13785 implemented with custom @var{basefreq} and @var{endfreq}, use @var{axisfile}
13789 Specify font color expression. This is arithmetic expression that should return
13790 integer value 0xRRGGBB. It can contain variables:
13792 @item frequency, freq, f
13793 the frequency where it is evaluated
13794 @item timeclamp, tc
13795 the value of @var{timeclamp} option
13800 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
13801 @item r(x), g(x), b(x)
13802 red, green, and blue value of intensity x.
13804 Default value is @code{st(0, (midi(f)-59.5)/12);
13805 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
13806 r(1-ld(1)) + b(ld(1))}.
13809 Specify image file to draw the axis. This option override @var{fontfile} and
13810 @var{fontcolor} option.
13813 Enable/disable drawing text to the axis. If it is set to @code{0}, drawing to
13814 the axis is disabled, ignoring @var{fontfile} and @var{axisfile} option.
13815 Default value is @code{1}.
13819 @subsection Examples
13823 Playing audio while showing the spectrum:
13825 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
13829 Same as above, but with frame rate 30 fps:
13831 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
13835 Playing at 1280x720:
13837 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=s=1280x720:count=4 [out0]'
13841 Disable sonogram display:
13847 A1 and its harmonics: A1, A2, (near)E3, A3:
13849 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
13850 asplit[a][out1]; [a] showcqt [out0]'
13854 Same as above, but with more accuracy in frequency domain:
13856 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
13857 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
13863 bar_v=10:sono_v=bar_v*a_weighting(f)
13867 Custom gamma, now spectrum is linear to the amplitude.
13873 Custom tlength equation:
13875 tc=0.33:tlength='st(0,0.17); 384*tc / (384 / ld(0) + tc*f /(1-ld(0))) + 384*tc / (tc*f / ld(0) + 384 /(1-ld(0)))'
13879 Custom fontcolor and fontfile, C-note is colored green, others are colored blue:
13881 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf
13885 Custom frequency range with custom axis using image file:
13887 axisfile=myaxis.png:basefreq=40:endfreq=10000
13893 Convert input audio to video output representing the audio power spectrum.
13894 Audio amplitude is on Y-axis while frequency is on X-axis.
13896 The filter accepts the following options:
13900 Specify size of video. For the syntax of this option, check the
13901 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13902 Default is @code{1024x512}.
13906 This set how each frequency bin will be represented.
13908 It accepts the following values:
13914 Default is @code{bar}.
13917 Set amplitude scale.
13919 It accepts the following values:
13933 Default is @code{log}.
13936 Set frequency scale.
13938 It accepts the following values:
13947 Reverse logarithmic scale.
13949 Default is @code{lin}.
13954 It accepts the following values:
13970 Default is @code{w2048}
13973 Set windowing function.
13975 It accepts the following values:
13992 Default is @code{hanning}.
13995 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
13996 which means optimal overlap for selected window function will be picked.
13999 Set time averaging. Setting this to 0 will display current maximal peaks.
14000 Default is @code{1}, which means time averaging is disabled.
14003 Specify list of colors separated by space or by '|' which will be used to
14004 draw channel frequencies. Unrecognized or missing colors will be replaced
14008 @section showspectrum
14010 Convert input audio to a video output, representing the audio frequency
14013 The filter accepts the following options:
14017 Specify the video size for the output. For the syntax of this option, check the
14018 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14019 Default value is @code{640x512}.
14022 Specify how the spectrum should slide along the window.
14024 It accepts the following values:
14027 the samples start again on the left when they reach the right
14029 the samples scroll from right to left
14031 frames are only produced when the samples reach the right
14034 Default value is @code{replace}.
14037 Specify display mode.
14039 It accepts the following values:
14042 all channels are displayed in the same row
14044 all channels are displayed in separate rows
14047 Default value is @samp{combined}.
14050 Specify display color mode.
14052 It accepts the following values:
14055 each channel is displayed in a separate color
14057 each channel is is displayed using the same color scheme
14060 Default value is @samp{channel}.
14063 Specify scale used for calculating intensity color values.
14065 It accepts the following values:
14070 square root, default
14077 Default value is @samp{sqrt}.
14080 Set saturation modifier for displayed colors. Negative values provide
14081 alternative color scheme. @code{0} is no saturation at all.
14082 Saturation must be in [-10.0, 10.0] range.
14083 Default value is @code{1}.
14086 Set window function.
14088 It accepts the following values:
14091 No samples pre-processing (do not expect this to be faster)
14100 Default value is @code{hann}.
14103 The usage is very similar to the showwaves filter; see the examples in that
14106 @subsection Examples
14110 Large window with logarithmic color scaling:
14112 showspectrum=s=1280x480:scale=log
14116 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
14118 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
14119 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
14123 @section showvolume
14125 Convert input audio volume to a video output.
14127 The filter accepts the following options:
14134 Set border width, allowed range is [0, 5]. Default is 1.
14137 Set channel width, allowed range is [40, 1080]. Default is 400.
14140 Set channel height, allowed range is [1, 100]. Default is 20.
14143 Set fade, allowed range is [1, 255]. Default is 20.
14146 Set volume color expression.
14148 The expression can use the following variables:
14152 Current max volume of channel in dB.
14155 Current channel number, starting from 0.
14159 If set, displays channel names. Default is enabled.
14164 Convert input audio to a video output, representing the samples waves.
14166 The filter accepts the following options:
14170 Specify the video size for the output. For the syntax of this option, check the
14171 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14172 Default value is @code{600x240}.
14177 Available values are:
14180 Draw a point for each sample.
14183 Draw a vertical line for each sample.
14186 Draw a point for each sample and a line between them.
14189 Draw a centered vertical line for each sample.
14192 Default value is @code{point}.
14195 Set the number of samples which are printed on the same column. A
14196 larger value will decrease the frame rate. Must be a positive
14197 integer. This option can be set only if the value for @var{rate}
14198 is not explicitly specified.
14201 Set the (approximate) output frame rate. This is done by setting the
14202 option @var{n}. Default value is "25".
14204 @item split_channels
14205 Set if channels should be drawn separately or overlap. Default value is 0.
14209 @subsection Examples
14213 Output the input file audio and the corresponding video representation
14216 amovie=a.mp3,asplit[out0],showwaves[out1]
14220 Create a synthetic signal and show it with showwaves, forcing a
14221 frame rate of 30 frames per second:
14223 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
14227 @section showwavespic
14229 Convert input audio to a single video frame, representing the samples waves.
14231 The filter accepts the following options:
14235 Specify the video size for the output. For the syntax of this option, check the
14236 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14237 Default value is @code{600x240}.
14239 @item split_channels
14240 Set if channels should be drawn separately or overlap. Default value is 0.
14243 @subsection Examples
14247 Extract a channel split representation of the wave form of a whole audio track
14248 in a 1024x800 picture using @command{ffmpeg}:
14250 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
14254 @section split, asplit
14256 Split input into several identical outputs.
14258 @code{asplit} works with audio input, @code{split} with video.
14260 The filter accepts a single parameter which specifies the number of outputs. If
14261 unspecified, it defaults to 2.
14263 @subsection Examples
14267 Create two separate outputs from the same input:
14269 [in] split [out0][out1]
14273 To create 3 or more outputs, you need to specify the number of
14276 [in] asplit=3 [out0][out1][out2]
14280 Create two separate outputs from the same input, one cropped and
14283 [in] split [splitout1][splitout2];
14284 [splitout1] crop=100:100:0:0 [cropout];
14285 [splitout2] pad=200:200:100:100 [padout];
14289 Create 5 copies of the input audio with @command{ffmpeg}:
14291 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
14297 Receive commands sent through a libzmq client, and forward them to
14298 filters in the filtergraph.
14300 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
14301 must be inserted between two video filters, @code{azmq} between two
14304 To enable these filters you need to install the libzmq library and
14305 headers and configure FFmpeg with @code{--enable-libzmq}.
14307 For more information about libzmq see:
14308 @url{http://www.zeromq.org/}
14310 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
14311 receives messages sent through a network interface defined by the
14312 @option{bind_address} option.
14314 The received message must be in the form:
14316 @var{TARGET} @var{COMMAND} [@var{ARG}]
14319 @var{TARGET} specifies the target of the command, usually the name of
14320 the filter class or a specific filter instance name.
14322 @var{COMMAND} specifies the name of the command for the target filter.
14324 @var{ARG} is optional and specifies the optional argument list for the
14325 given @var{COMMAND}.
14327 Upon reception, the message is processed and the corresponding command
14328 is injected into the filtergraph. Depending on the result, the filter
14329 will send a reply to the client, adopting the format:
14331 @var{ERROR_CODE} @var{ERROR_REASON}
14335 @var{MESSAGE} is optional.
14337 @subsection Examples
14339 Look at @file{tools/zmqsend} for an example of a zmq client which can
14340 be used to send commands processed by these filters.
14342 Consider the following filtergraph generated by @command{ffplay}
14344 ffplay -dumpgraph 1 -f lavfi "
14345 color=s=100x100:c=red [l];
14346 color=s=100x100:c=blue [r];
14347 nullsrc=s=200x100, zmq [bg];
14348 [bg][l] overlay [bg+l];
14349 [bg+l][r] overlay=x=100 "
14352 To change the color of the left side of the video, the following
14353 command can be used:
14355 echo Parsed_color_0 c yellow | tools/zmqsend
14358 To change the right side:
14360 echo Parsed_color_1 c pink | tools/zmqsend
14363 @c man end MULTIMEDIA FILTERS
14365 @chapter Multimedia Sources
14366 @c man begin MULTIMEDIA SOURCES
14368 Below is a description of the currently available multimedia sources.
14372 This is the same as @ref{movie} source, except it selects an audio
14378 Read audio and/or video stream(s) from a movie container.
14380 It accepts the following parameters:
14384 The name of the resource to read (not necessarily a file; it can also be a
14385 device or a stream accessed through some protocol).
14387 @item format_name, f
14388 Specifies the format assumed for the movie to read, and can be either
14389 the name of a container or an input device. If not specified, the
14390 format is guessed from @var{movie_name} or by probing.
14392 @item seek_point, sp
14393 Specifies the seek point in seconds. The frames will be output
14394 starting from this seek point. The parameter is evaluated with
14395 @code{av_strtod}, so the numerical value may be suffixed by an IS
14396 postfix. The default value is "0".
14399 Specifies the streams to read. Several streams can be specified,
14400 separated by "+". The source will then have as many outputs, in the
14401 same order. The syntax is explained in the ``Stream specifiers''
14402 section in the ffmpeg manual. Two special names, "dv" and "da" specify
14403 respectively the default (best suited) video and audio stream. Default
14404 is "dv", or "da" if the filter is called as "amovie".
14406 @item stream_index, si
14407 Specifies the index of the video stream to read. If the value is -1,
14408 the most suitable video stream will be automatically selected. The default
14409 value is "-1". Deprecated. If the filter is called "amovie", it will select
14410 audio instead of video.
14413 Specifies how many times to read the stream in sequence.
14414 If the value is less than 1, the stream will be read again and again.
14415 Default value is "1".
14417 Note that when the movie is looped the source timestamps are not
14418 changed, so it will generate non monotonically increasing timestamps.
14421 It allows overlaying a second video on top of the main input of
14422 a filtergraph, as shown in this graph:
14424 input -----------> deltapts0 --> overlay --> output
14427 movie --> scale--> deltapts1 -------+
14429 @subsection Examples
14433 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
14434 on top of the input labelled "in":
14436 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
14437 [in] setpts=PTS-STARTPTS [main];
14438 [main][over] overlay=16:16 [out]
14442 Read from a video4linux2 device, and overlay it on top of the input
14445 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
14446 [in] setpts=PTS-STARTPTS [main];
14447 [main][over] overlay=16:16 [out]
14451 Read the first video stream and the audio stream with id 0x81 from
14452 dvd.vob; the video is connected to the pad named "video" and the audio is
14453 connected to the pad named "audio":
14455 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
14459 @c man end MULTIMEDIA SOURCES