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.
1173 @section astreamsync
1175 Forward two audio streams and control the order the buffers are forwarded.
1177 The filter accepts the following options:
1181 Set the expression deciding which stream should be
1182 forwarded next: if the result is negative, the first stream is forwarded; if
1183 the result is positive or zero, the second stream is forwarded. It can use
1184 the following variables:
1188 number of buffers forwarded so far on each stream
1190 number of samples forwarded so far on each stream
1192 current timestamp of each stream
1195 The default value is @code{t1-t2}, which means to always forward the stream
1196 that has a smaller timestamp.
1199 @subsection Examples
1201 Stress-test @code{amerge} by randomly sending buffers on the wrong
1202 input, while avoiding too much of a desynchronization:
1204 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
1205 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
1211 Synchronize audio data with timestamps by squeezing/stretching it and/or
1212 dropping samples/adding silence when needed.
1214 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1216 It accepts the following parameters:
1220 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1221 by default. When disabled, time gaps are covered with silence.
1224 The minimum difference between timestamps and audio data (in seconds) to trigger
1225 adding/dropping samples. The default value is 0.1. If you get an imperfect
1226 sync with this filter, try setting this parameter to 0.
1229 The maximum compensation in samples per second. Only relevant with compensate=1.
1230 The default value is 500.
1233 Assume that the first PTS should be this value. The time base is 1 / sample
1234 rate. This allows for padding/trimming at the start of the stream. By default,
1235 no assumption is made about the first frame's expected PTS, so no padding or
1236 trimming is done. For example, this could be set to 0 to pad the beginning with
1237 silence if an audio stream starts after the video stream or to trim any samples
1238 with a negative PTS due to encoder delay.
1246 The filter accepts exactly one parameter, the audio tempo. If not
1247 specified then the filter will assume nominal 1.0 tempo. Tempo must
1248 be in the [0.5, 2.0] range.
1250 @subsection Examples
1254 Slow down audio to 80% tempo:
1260 To speed up audio to 125% tempo:
1268 Trim the input so that the output contains one continuous subpart of the input.
1270 It accepts the following parameters:
1273 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1274 sample with the timestamp @var{start} will be the first sample in the output.
1277 Specify time of the first audio sample that will be dropped, i.e. the
1278 audio sample immediately preceding the one with the timestamp @var{end} will be
1279 the last sample in the output.
1282 Same as @var{start}, except this option sets the start timestamp in samples
1286 Same as @var{end}, except this option sets the end timestamp in samples instead
1290 The maximum duration of the output in seconds.
1293 The number of the first sample that should be output.
1296 The number of the first sample that should be dropped.
1299 @option{start}, @option{end}, and @option{duration} are expressed as time
1300 duration specifications; see
1301 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1303 Note that the first two sets of the start/end options and the @option{duration}
1304 option look at the frame timestamp, while the _sample options simply count the
1305 samples that pass through the filter. So start/end_pts and start/end_sample will
1306 give different results when the timestamps are wrong, inexact or do not start at
1307 zero. Also note that this filter does not modify the timestamps. If you wish
1308 to have the output timestamps start at zero, insert the asetpts filter after the
1311 If multiple start or end options are set, this filter tries to be greedy and
1312 keep all samples that match at least one of the specified constraints. To keep
1313 only the part that matches all the constraints at once, chain multiple atrim
1316 The defaults are such that all the input is kept. So it is possible to set e.g.
1317 just the end values to keep everything before the specified time.
1322 Drop everything except the second minute of input:
1324 ffmpeg -i INPUT -af atrim=60:120
1328 Keep only the first 1000 samples:
1330 ffmpeg -i INPUT -af atrim=end_sample=1000
1337 Apply a two-pole Butterworth band-pass filter with central
1338 frequency @var{frequency}, and (3dB-point) band-width width.
1339 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1340 instead of the default: constant 0dB peak gain.
1341 The filter roll off at 6dB per octave (20dB per decade).
1343 The filter accepts the following options:
1347 Set the filter's central frequency. Default is @code{3000}.
1350 Constant skirt gain if set to 1. Defaults to 0.
1353 Set method to specify band-width of filter.
1366 Specify the band-width of a filter in width_type units.
1371 Apply a two-pole Butterworth band-reject filter with central
1372 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1373 The filter roll off at 6dB per octave (20dB per decade).
1375 The filter accepts the following options:
1379 Set the filter's central frequency. Default is @code{3000}.
1382 Set method to specify band-width of filter.
1395 Specify the band-width of a filter in width_type units.
1400 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1401 shelving filter with a response similar to that of a standard
1402 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1404 The filter accepts the following options:
1408 Give the gain at 0 Hz. Its useful range is about -20
1409 (for a large cut) to +20 (for a large boost).
1410 Beware of clipping when using a positive gain.
1413 Set the filter's central frequency and so can be used
1414 to extend or reduce the frequency range to be boosted or cut.
1415 The default value is @code{100} Hz.
1418 Set method to specify band-width of filter.
1431 Determine how steep is the filter's shelf transition.
1436 Apply a biquad IIR filter with the given coefficients.
1437 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1438 are the numerator and denominator coefficients respectively.
1441 Bauer stereo to binaural transformation, which improves headphone listening of
1442 stereo audio records.
1444 It accepts the following parameters:
1448 Pre-defined crossfeed level.
1452 Default level (fcut=700, feed=50).
1455 Chu Moy circuit (fcut=700, feed=60).
1458 Jan Meier circuit (fcut=650, feed=95).
1463 Cut frequency (in Hz).
1472 Remap input channels to new locations.
1474 It accepts the following parameters:
1476 @item channel_layout
1477 The channel layout of the output stream.
1480 Map channels from input to output. The argument is a '|'-separated list of
1481 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1482 @var{in_channel} form. @var{in_channel} can be either the name of the input
1483 channel (e.g. FL for front left) or its index in the input channel layout.
1484 @var{out_channel} is the name of the output channel or its index in the output
1485 channel layout. If @var{out_channel} is not given then it is implicitly an
1486 index, starting with zero and increasing by one for each mapping.
1489 If no mapping is present, the filter will implicitly map input channels to
1490 output channels, preserving indices.
1492 For example, assuming a 5.1+downmix input MOV file,
1494 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1496 will create an output WAV file tagged as stereo from the downmix channels of
1499 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1501 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav
1504 @section channelsplit
1506 Split each channel from an input audio stream into a separate output stream.
1508 It accepts the following parameters:
1510 @item channel_layout
1511 The channel layout of the input stream. The default is "stereo".
1514 For example, assuming a stereo input MP3 file,
1516 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1518 will create an output Matroska file with two audio streams, one containing only
1519 the left channel and the other the right channel.
1521 Split a 5.1 WAV file into per-channel files:
1523 ffmpeg -i in.wav -filter_complex
1524 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1525 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1526 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1531 Add a chorus effect to the audio.
1533 Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
1535 Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
1536 constant, with chorus, it is varied using using sinusoidal or triangular modulation.
1537 The modulation depth defines the range the modulated delay is played before or after
1538 the delay. Hence the delayed sound will sound slower or faster, that is the delayed
1539 sound tuned around the original one, like in a chorus where some vocals are slightly
1542 It accepts the following parameters:
1545 Set input gain. Default is 0.4.
1548 Set output gain. Default is 0.4.
1551 Set delays. A typical delay is around 40ms to 60ms.
1563 @subsection Examples
1569 chorus=0.7:0.9:55:0.4:0.25:2
1575 chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
1579 Fuller sounding chorus with three delays:
1581 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
1586 Compress or expand the audio's dynamic range.
1588 It accepts the following parameters:
1594 A list of times in seconds for each channel over which the instantaneous level
1595 of the input signal is averaged to determine its volume. @var{attacks} refers to
1596 increase of volume and @var{decays} refers to decrease of volume. For most
1597 situations, the attack time (response to the audio getting louder) should be
1598 shorter than the decay time, because the human ear is more sensitive to sudden
1599 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1600 a typical value for decay is 0.8 seconds.
1601 If specified number of attacks & decays is lower than number of channels, the last
1602 set attack/decay will be used for all remaining channels.
1605 A list of points for the transfer function, specified in dB relative to the
1606 maximum possible signal amplitude. Each key points list must be defined using
1607 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1608 @code{x0/y0 x1/y1 x2/y2 ....}
1610 The input values must be in strictly increasing order but the transfer function
1611 does not have to be monotonically rising. The point @code{0/0} is assumed but
1612 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1613 function are @code{-70/-70|-60/-20}.
1616 Set the curve radius in dB for all joints. It defaults to 0.01.
1619 Set the additional gain in dB to be applied at all points on the transfer
1620 function. This allows for easy adjustment of the overall gain.
1624 Set an initial volume, in dB, to be assumed for each channel when filtering
1625 starts. This permits the user to supply a nominal level initially, so that, for
1626 example, a very large gain is not applied to initial signal levels before the
1627 companding has begun to operate. A typical value for audio which is initially
1628 quiet is -90 dB. It defaults to 0.
1631 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1632 delayed before being fed to the volume adjuster. Specifying a delay
1633 approximately equal to the attack/decay times allows the filter to effectively
1634 operate in predictive rather than reactive mode. It defaults to 0.
1638 @subsection Examples
1642 Make music with both quiet and loud passages suitable for listening to in a
1645 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1648 Another example for audio with whisper and explosion parts:
1650 compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
1654 A noise gate for when the noise is at a lower level than the signal:
1656 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1660 Here is another noise gate, this time for when the noise is at a higher level
1661 than the signal (making it, in some ways, similar to squelch):
1663 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1668 Apply a DC shift to the audio.
1670 This can be useful to remove a DC offset (caused perhaps by a hardware problem
1671 in the recording chain) from the audio. The effect of a DC offset is reduced
1672 headroom and hence volume. The @ref{astats} filter can be used to determine if
1673 a signal has a DC offset.
1677 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
1681 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
1682 used to prevent clipping.
1686 Dynamic Audio Normalizer.
1688 This filter applies a certain amount of gain to the input audio in order
1689 to bring its peak magnitude to a target level (e.g. 0 dBFS). However, in
1690 contrast to more "simple" normalization algorithms, the Dynamic Audio
1691 Normalizer *dynamically* re-adjusts the gain factor to the input audio.
1692 This allows for applying extra gain to the "quiet" sections of the audio
1693 while avoiding distortions or clipping the "loud" sections. In other words:
1694 The Dynamic Audio Normalizer will "even out" the volume of quiet and loud
1695 sections, in the sense that the volume of each section is brought to the
1696 same target level. Note, however, that the Dynamic Audio Normalizer achieves
1697 this goal *without* applying "dynamic range compressing". It will retain 100%
1698 of the dynamic range *within* each section of the audio file.
1702 Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.
1703 Default is 500 milliseconds.
1704 The Dynamic Audio Normalizer processes the input audio in small chunks,
1705 referred to as frames. This is required, because a peak magnitude has no
1706 meaning for just a single sample value. Instead, we need to determine the
1707 peak magnitude for a contiguous sequence of sample values. While a "standard"
1708 normalizer would simply use the peak magnitude of the complete file, the
1709 Dynamic Audio Normalizer determines the peak magnitude individually for each
1710 frame. The length of a frame is specified in milliseconds. By default, the
1711 Dynamic Audio Normalizer uses a frame length of 500 milliseconds, which has
1712 been found to give good results with most files.
1713 Note that the exact frame length, in number of samples, will be determined
1714 automatically, based on the sampling rate of the individual input audio file.
1717 Set the Gaussian filter window size. In range from 3 to 301, must be odd
1718 number. Default is 31.
1719 Probably the most important parameter of the Dynamic Audio Normalizer is the
1720 @code{window size} of the Gaussian smoothing filter. The filter's window size
1721 is specified in frames, centered around the current frame. For the sake of
1722 simplicity, this must be an odd number. Consequently, the default value of 31
1723 takes into account the current frame, as well as the 15 preceding frames and
1724 the 15 subsequent frames. Using a larger window results in a stronger
1725 smoothing effect and thus in less gain variation, i.e. slower gain
1726 adaptation. Conversely, using a smaller window results in a weaker smoothing
1727 effect and thus in more gain variation, i.e. faster gain adaptation.
1728 In other words, the more you increase this value, the more the Dynamic Audio
1729 Normalizer will behave like a "traditional" normalization filter. On the
1730 contrary, the more you decrease this value, the more the Dynamic Audio
1731 Normalizer will behave like a dynamic range compressor.
1734 Set the target peak value. This specifies the highest permissible magnitude
1735 level for the normalized audio input. This filter will try to approach the
1736 target peak magnitude as closely as possible, but at the same time it also
1737 makes sure that the normalized signal will never exceed the peak magnitude.
1738 A frame's maximum local gain factor is imposed directly by the target peak
1739 magnitude. The default value is 0.95 and thus leaves a headroom of 5%*.
1740 It is not recommended to go above this value.
1743 Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.
1744 The Dynamic Audio Normalizer determines the maximum possible (local) gain
1745 factor for each input frame, i.e. the maximum gain factor that does not
1746 result in clipping or distortion. The maximum gain factor is determined by
1747 the frame's highest magnitude sample. However, the Dynamic Audio Normalizer
1748 additionally bounds the frame's maximum gain factor by a predetermined
1749 (global) maximum gain factor. This is done in order to avoid excessive gain
1750 factors in "silent" or almost silent frames. By default, the maximum gain
1751 factor is 10.0, For most inputs the default value should be sufficient and
1752 it usually is not recommended to increase this value. Though, for input
1753 with an extremely low overall volume level, it may be necessary to allow even
1754 higher gain factors. Note, however, that the Dynamic Audio Normalizer does
1755 not simply apply a "hard" threshold (i.e. cut off values above the threshold).
1756 Instead, a "sigmoid" threshold function will be applied. This way, the
1757 gain factors will smoothly approach the threshold value, but never exceed that
1761 Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.
1762 By default, the Dynamic Audio Normalizer performs "peak" normalization.
1763 This means that the maximum local gain factor for each frame is defined
1764 (only) by the frame's highest magnitude sample. This way, the samples can
1765 be amplified as much as possible without exceeding the maximum signal
1766 level, i.e. without clipping. Optionally, however, the Dynamic Audio
1767 Normalizer can also take into account the frame's root mean square,
1768 abbreviated RMS. In electrical engineering, the RMS is commonly used to
1769 determine the power of a time-varying signal. It is therefore considered
1770 that the RMS is a better approximation of the "perceived loudness" than
1771 just looking at the signal's peak magnitude. Consequently, by adjusting all
1772 frames to a constant RMS value, a uniform "perceived loudness" can be
1773 established. If a target RMS value has been specified, a frame's local gain
1774 factor is defined as the factor that would result in exactly that RMS value.
1775 Note, however, that the maximum local gain factor is still restricted by the
1776 frame's highest magnitude sample, in order to prevent clipping.
1779 Enable channels coupling. By default is enabled.
1780 By default, the Dynamic Audio Normalizer will amplify all channels by the same
1781 amount. This means the same gain factor will be applied to all channels, i.e.
1782 the maximum possible gain factor is determined by the "loudest" channel.
1783 However, in some recordings, it may happen that the volume of the different
1784 channels is uneven, e.g. one channel may be "quieter" than the other one(s).
1785 In this case, this option can be used to disable the channel coupling. This way,
1786 the gain factor will be determined independently for each channel, depending
1787 only on the individual channel's highest magnitude sample. This allows for
1788 harmonizing the volume of the different channels.
1791 Enable DC bias correction. By default is disabled.
1792 An audio signal (in the time domain) is a sequence of sample values.
1793 In the Dynamic Audio Normalizer these sample values are represented in the
1794 -1.0 to 1.0 range, regardless of the original input format. Normally, the
1795 audio signal, or "waveform", should be centered around the zero point.
1796 That means if we calculate the mean value of all samples in a file, or in a
1797 single frame, then the result should be 0.0 or at least very close to that
1798 value. If, however, there is a significant deviation of the mean value from
1799 0.0, in either positive or negative direction, this is referred to as a
1800 DC bias or DC offset. Since a DC bias is clearly undesirable, the Dynamic
1801 Audio Normalizer provides optional DC bias correction.
1802 With DC bias correction enabled, the Dynamic Audio Normalizer will determine
1803 the mean value, or "DC correction" offset, of each input frame and subtract
1804 that value from all of the frame's sample values which ensures those samples
1805 are centered around 0.0 again. Also, in order to avoid "gaps" at the frame
1806 boundaries, the DC correction offset values will be interpolated smoothly
1807 between neighbouring frames.
1810 Enable alternative boundary mode. By default is disabled.
1811 The Dynamic Audio Normalizer takes into account a certain neighbourhood
1812 around each frame. This includes the preceding frames as well as the
1813 subsequent frames. However, for the "boundary" frames, located at the very
1814 beginning and at the very end of the audio file, not all neighbouring
1815 frames are available. In particular, for the first few frames in the audio
1816 file, the preceding frames are not known. And, similarly, for the last few
1817 frames in the audio file, the subsequent frames are not known. Thus, the
1818 question arises which gain factors should be assumed for the missing frames
1819 in the "boundary" region. The Dynamic Audio Normalizer implements two modes
1820 to deal with this situation. The default boundary mode assumes a gain factor
1821 of exactly 1.0 for the missing frames, resulting in a smooth "fade in" and
1822 "fade out" at the beginning and at the end of the input, respectively.
1825 Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
1826 By default, the Dynamic Audio Normalizer does not apply "traditional"
1827 compression. This means that signal peaks will not be pruned and thus the
1828 full dynamic range will be retained within each local neighbourhood. However,
1829 in some cases it may be desirable to combine the Dynamic Audio Normalizer's
1830 normalization algorithm with a more "traditional" compression.
1831 For this purpose, the Dynamic Audio Normalizer provides an optional compression
1832 (thresholding) function. If (and only if) the compression feature is enabled,
1833 all input frames will be processed by a soft knee thresholding function prior
1834 to the actual normalization process. Put simply, the thresholding function is
1835 going to prune all samples whose magnitude exceeds a certain threshold value.
1836 However, the Dynamic Audio Normalizer does not simply apply a fixed threshold
1837 value. Instead, the threshold value will be adjusted for each individual
1839 In general, smaller parameters result in stronger compression, and vice versa.
1840 Values below 3.0 are not recommended, because audible distortion may appear.
1845 Make audio easier to listen to on headphones.
1847 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1848 so that when listened to on headphones the stereo image is moved from
1849 inside your head (standard for headphones) to outside and in front of
1850 the listener (standard for speakers).
1856 Apply a two-pole peaking equalisation (EQ) filter. With this
1857 filter, the signal-level at and around a selected frequency can
1858 be increased or decreased, whilst (unlike bandpass and bandreject
1859 filters) that at all other frequencies is unchanged.
1861 In order to produce complex equalisation curves, this filter can
1862 be given several times, each with a different central frequency.
1864 The filter accepts the following options:
1868 Set the filter's central frequency in Hz.
1871 Set method to specify band-width of filter.
1884 Specify the band-width of a filter in width_type units.
1887 Set the required gain or attenuation in dB.
1888 Beware of clipping when using a positive gain.
1891 @subsection Examples
1894 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1896 equalizer=f=1000:width_type=h:width=200:g=-10
1900 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1902 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1906 @section extrastereo
1908 Linearly increases the difference between left and right channels which
1909 adds some sort of "live" effect to playback.
1911 The filter accepts the following option:
1915 Sets the difference coefficient (default: 2.5). 0.0 means mono sound
1916 (average of both channels), with 1.0 sound will be unchanged, with
1917 -1.0 left and right channels will be swapped.
1920 Enable clipping. By default is enabled.
1924 Apply a flanging effect to the audio.
1926 The filter accepts the following options:
1930 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1933 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1936 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1940 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1941 Default value is 71.
1944 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1947 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1948 Default value is @var{sinusoidal}.
1951 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1952 Default value is 25.
1955 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1956 Default is @var{linear}.
1961 Apply a high-pass filter with 3dB point frequency.
1962 The filter can be either single-pole, or double-pole (the default).
1963 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1965 The filter accepts the following options:
1969 Set frequency in Hz. Default is 3000.
1972 Set number of poles. Default is 2.
1975 Set method to specify band-width of filter.
1988 Specify the band-width of a filter in width_type units.
1989 Applies only to double-pole filter.
1990 The default is 0.707q and gives a Butterworth response.
1995 Join multiple input streams into one multi-channel stream.
1997 It accepts the following parameters:
2001 The number of input streams. It defaults to 2.
2003 @item channel_layout
2004 The desired output channel layout. It defaults to stereo.
2007 Map channels from inputs to output. The argument is a '|'-separated list of
2008 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
2009 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
2010 can be either the name of the input channel (e.g. FL for front left) or its
2011 index in the specified input stream. @var{out_channel} is the name of the output
2015 The filter will attempt to guess the mappings when they are not specified
2016 explicitly. It does so by first trying to find an unused matching input channel
2017 and if that fails it picks the first unused input channel.
2019 Join 3 inputs (with properly set channel layouts):
2021 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
2024 Build a 5.1 output from 6 single-channel streams:
2026 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
2027 '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'
2033 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
2035 To enable compilation of this filter you need to configure FFmpeg with
2036 @code{--enable-ladspa}.
2040 Specifies the name of LADSPA plugin library to load. If the environment
2041 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
2042 each one of the directories specified by the colon separated list in
2043 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
2044 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
2045 @file{/usr/lib/ladspa/}.
2048 Specifies the plugin within the library. Some libraries contain only
2049 one plugin, but others contain many of them. If this is not set filter
2050 will list all available plugins within the specified library.
2053 Set the '|' separated list of controls which are zero or more floating point
2054 values that determine the behavior of the loaded plugin (for example delay,
2056 Controls need to be defined using the following syntax:
2057 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
2058 @var{valuei} is the value set on the @var{i}-th control.
2059 Alternatively they can be also defined using the following syntax:
2060 @var{value0}|@var{value1}|@var{value2}|..., where
2061 @var{valuei} is the value set on the @var{i}-th control.
2062 If @option{controls} is set to @code{help}, all available controls and
2063 their valid ranges are printed.
2065 @item sample_rate, s
2066 Specify the sample rate, default to 44100. Only used if plugin have
2070 Set the number of samples per channel per each output frame, default
2071 is 1024. Only used if plugin have zero inputs.
2074 Set the minimum duration of the sourced audio. See
2075 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2076 for the accepted syntax.
2077 Note that the resulting duration may be greater than the specified duration,
2078 as the generated audio is always cut at the end of a complete frame.
2079 If not specified, or the expressed duration is negative, the audio is
2080 supposed to be generated forever.
2081 Only used if plugin have zero inputs.
2085 @subsection Examples
2089 List all available plugins within amp (LADSPA example plugin) library:
2095 List all available controls and their valid ranges for @code{vcf_notch}
2096 plugin from @code{VCF} library:
2098 ladspa=f=vcf:p=vcf_notch:c=help
2102 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
2105 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2109 Add reverberation to the audio using TAP-plugins
2110 (Tom's Audio Processing plugins):
2112 ladspa=file=tap_reverb:tap_reverb
2116 Generate white noise, with 0.2 amplitude:
2118 ladspa=file=cmt:noise_source_white:c=c0=.2
2122 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2123 @code{C* Audio Plugin Suite} (CAPS) library:
2125 ladspa=file=caps:Click:c=c1=20'
2129 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2131 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2135 Increase volume by 20dB using fast lookahead limiter from Steve Harris
2136 @code{SWH Plugins} collection:
2138 ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2
2142 Attenuate low frequencies using Multiband EQ from Steve Harris
2143 @code{SWH Plugins} collection:
2145 ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0
2149 @subsection Commands
2151 This filter supports the following commands:
2154 Modify the @var{N}-th control value.
2156 If the specified value is not valid, it is ignored and prior one is kept.
2161 Apply a low-pass filter with 3dB point frequency.
2162 The filter can be either single-pole or double-pole (the default).
2163 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2165 The filter accepts the following options:
2169 Set frequency in Hz. Default is 500.
2172 Set number of poles. Default is 2.
2175 Set method to specify band-width of filter.
2188 Specify the band-width of a filter in width_type units.
2189 Applies only to double-pole filter.
2190 The default is 0.707q and gives a Butterworth response.
2196 Mix channels with specific gain levels. The filter accepts the output
2197 channel layout followed by a set of channels definitions.
2199 This filter is also designed to efficiently remap the channels of an audio
2202 The filter accepts parameters of the form:
2203 "@var{l}|@var{outdef}|@var{outdef}|..."
2207 output channel layout or number of channels
2210 output channel specification, of the form:
2211 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2214 output channel to define, either a channel name (FL, FR, etc.) or a channel
2215 number (c0, c1, etc.)
2218 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2221 input channel to use, see out_name for details; it is not possible to mix
2222 named and numbered input channels
2225 If the `=' in a channel specification is replaced by `<', then the gains for
2226 that specification will be renormalized so that the total is 1, thus
2227 avoiding clipping noise.
2229 @subsection Mixing examples
2231 For example, if you want to down-mix from stereo to mono, but with a bigger
2232 factor for the left channel:
2234 pan=1c|c0=0.9*c0+0.1*c1
2237 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2238 7-channels surround:
2240 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2243 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2244 that should be preferred (see "-ac" option) unless you have very specific
2247 @subsection Remapping examples
2249 The channel remapping will be effective if, and only if:
2252 @item gain coefficients are zeroes or ones,
2253 @item only one input per channel output,
2256 If all these conditions are satisfied, the filter will notify the user ("Pure
2257 channel mapping detected"), and use an optimized and lossless method to do the
2260 For example, if you have a 5.1 source and want a stereo audio stream by
2261 dropping the extra channels:
2263 pan="stereo| c0=FL | c1=FR"
2266 Given the same source, you can also switch front left and front right channels
2267 and keep the input channel layout:
2269 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2272 If the input is a stereo audio stream, you can mute the front left channel (and
2273 still keep the stereo channel layout) with:
2278 Still with a stereo audio stream input, you can copy the right channel in both
2279 front left and right:
2281 pan="stereo| c0=FR | c1=FR"
2286 ReplayGain scanner filter. This filter takes an audio stream as an input and
2287 outputs it unchanged.
2288 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2292 Convert the audio sample format, sample rate and channel layout. It is
2293 not meant to be used directly.
2296 Apply time-stretching and pitch-shifting with librubberband.
2298 The filter accepts the following options:
2302 Set tempo scale factor.
2305 Set pitch scale factor.
2308 Set transients detector.
2309 Possible values are:
2318 Possible values are:
2327 Possible values are:
2334 Set processing window size.
2335 Possible values are:
2344 Possible values are:
2351 Enable formant preservation when shift pitching.
2352 Possible values are:
2360 Possible values are:
2369 Possible values are:
2376 @section sidechaincompress
2378 This filter acts like normal compressor but has the ability to compress
2379 detected signal using second input signal.
2380 It needs two input streams and returns one output stream.
2381 First input stream will be processed depending on second stream signal.
2382 The filtered signal then can be filtered with other filters in later stages of
2383 processing. See @ref{pan} and @ref{amerge} filter.
2385 The filter accepts the following options:
2389 If a signal of second stream raises above this level it will affect the gain
2390 reduction of first stream.
2391 By default is 0.125. Range is between 0.00097563 and 1.
2394 Set a ratio about which the signal is reduced. 1:2 means that if the level
2395 raised 4dB above the threshold, it will be only 2dB above after the reduction.
2396 Default is 2. Range is between 1 and 20.
2399 Amount of milliseconds the signal has to rise above the threshold before gain
2400 reduction starts. Default is 20. Range is between 0.01 and 2000.
2403 Amount of milliseconds the signal has to fall below the threshold before
2404 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
2407 Set the amount by how much signal will be amplified after processing.
2408 Default is 2. Range is from 1 and 64.
2411 Curve the sharp knee around the threshold to enter gain reduction more softly.
2412 Default is 2.82843. Range is between 1 and 8.
2415 Choose if the @code{average} level between all channels of side-chain stream
2416 or the louder(@code{maximum}) channel of side-chain stream affects the
2417 reduction. Default is @code{average}.
2420 Should the exact signal be taken in case of @code{peak} or an RMS one in case
2421 of @code{rms}. Default is @code{rms} which is mainly smoother.
2424 @subsection Examples
2428 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
2429 depending on the signal of 2nd input and later compressed signal to be
2430 merged with 2nd input:
2432 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
2436 @section silencedetect
2438 Detect silence in an audio stream.
2440 This filter logs a message when it detects that the input audio volume is less
2441 or equal to a noise tolerance value for a duration greater or equal to the
2442 minimum detected noise duration.
2444 The printed times and duration are expressed in seconds.
2446 The filter accepts the following options:
2450 Set silence duration until notification (default is 2 seconds).
2453 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
2454 specified value) or amplitude ratio. Default is -60dB, or 0.001.
2457 @subsection Examples
2461 Detect 5 seconds of silence with -50dB noise tolerance:
2463 silencedetect=n=-50dB:d=5
2467 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
2468 tolerance in @file{silence.mp3}:
2470 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
2474 @section silenceremove
2476 Remove silence from the beginning, middle or end of the audio.
2478 The filter accepts the following options:
2482 This value is used to indicate if audio should be trimmed at beginning of
2483 the audio. A value of zero indicates no silence should be trimmed from the
2484 beginning. When specifying a non-zero value, it trims audio up until it
2485 finds non-silence. Normally, when trimming silence from beginning of audio
2486 the @var{start_periods} will be @code{1} but it can be increased to higher
2487 values to trim all audio up to specific count of non-silence periods.
2488 Default value is @code{0}.
2490 @item start_duration
2491 Specify the amount of time that non-silence must be detected before it stops
2492 trimming audio. By increasing the duration, bursts of noises can be treated
2493 as silence and trimmed off. Default value is @code{0}.
2495 @item start_threshold
2496 This indicates what sample value should be treated as silence. For digital
2497 audio, a value of @code{0} may be fine but for audio recorded from analog,
2498 you may wish to increase the value to account for background noise.
2499 Can be specified in dB (in case "dB" is appended to the specified value)
2500 or amplitude ratio. Default value is @code{0}.
2503 Set the count for trimming silence from the end of audio.
2504 To remove silence from the middle of a file, specify a @var{stop_periods}
2505 that is negative. This value is then treated as a positive value and is
2506 used to indicate the effect should restart processing as specified by
2507 @var{start_periods}, making it suitable for removing periods of silence
2508 in the middle of the audio.
2509 Default value is @code{0}.
2512 Specify a duration of silence that must exist before audio is not copied any
2513 more. By specifying a higher duration, silence that is wanted can be left in
2515 Default value is @code{0}.
2517 @item stop_threshold
2518 This is the same as @option{start_threshold} but for trimming silence from
2520 Can be specified in dB (in case "dB" is appended to the specified value)
2521 or amplitude ratio. Default value is @code{0}.
2524 This indicate that @var{stop_duration} length of audio should be left intact
2525 at the beginning of each period of silence.
2526 For example, if you want to remove long pauses between words but do not want
2527 to remove the pauses completely. Default value is @code{0}.
2531 @subsection Examples
2535 The following example shows how this filter can be used to start a recording
2536 that does not contain the delay at the start which usually occurs between
2537 pressing the record button and the start of the performance:
2539 silenceremove=1:5:0.02
2543 @section stereotools
2545 This filter has some handy utilities to manage stereo signals, for converting
2546 M/S stereo recordings to L/R signal while having control over the parameters
2547 or spreading the stereo image of master track.
2549 The filter accepts the following options:
2553 Set input level before filtering for both channels. Defaults is 1.
2554 Allowed range is from 0.015625 to 64.
2557 Set output level after filtering for both channels. Defaults is 1.
2558 Allowed range is from 0.015625 to 64.
2561 Set input balance between both channels. Default is 0.
2562 Allowed range is from -1 to 1.
2565 Set output balance between both channels. Default is 0.
2566 Allowed range is from -1 to 1.
2569 Enable softclipping. Results in analog distortion instead of harsh digital 0dB
2570 clipping. Disabled by default.
2573 Mute the left channel. Disabled by default.
2576 Mute the right channel. Disabled by default.
2579 Change the phase of the left channel. Disabled by default.
2582 Change the phase of the right channel. Disabled by default.
2585 Set stereo mode. Available values are:
2589 Left/Right to Left/Right, this is default.
2592 Left/Right to Mid/Side.
2595 Mid/Side to Left/Right.
2598 Left/Right to Left/Left.
2601 Left/Right to Right/Right.
2604 Left/Right to Left + Right.
2607 Left/Right to Right/Left.
2611 Set level of side signal. Default is 1.
2612 Allowed range is from 0.015625 to 64.
2615 Set balance of side signal. Default is 0.
2616 Allowed range is from -1 to 1.
2619 Set level of the middle signal. Default is 1.
2620 Allowed range is from 0.015625 to 64.
2623 Set middle signal pan. Default is 0. Allowed range is from -1 to 1.
2626 Set stereo base between mono and inversed channels. Default is 0.
2627 Allowed range is from -1 to 1.
2630 Set delay in milliseconds how much to delay left from right channel and
2631 vice versa. Default is 0. Allowed range is from -20 to 20.
2634 Set S/C level. Default is 1. Allowed range is from 1 to 100.
2637 Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
2640 @section stereowiden
2642 This filter enhance the stereo effect by suppressing signal common to both
2643 channels and by delaying the signal of left into right and vice versa,
2644 thereby widening the stereo effect.
2646 The filter accepts the following options:
2650 Time in milliseconds of the delay of left signal into right and vice versa.
2651 Default is 20 milliseconds.
2654 Amount of gain in delayed signal into right and vice versa. Gives a delay
2655 effect of left signal in right output and vice versa which gives widening
2656 effect. Default is 0.3.
2659 Cross feed of left into right with inverted phase. This helps in suppressing
2660 the mono. If the value is 1 it will cancel all the signal common to both
2661 channels. Default is 0.3.
2664 Set level of input signal of original channel. Default is 0.8.
2669 Boost or cut treble (upper) frequencies of the audio using a two-pole
2670 shelving filter with a response similar to that of a standard
2671 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
2673 The filter accepts the following options:
2677 Give the gain at whichever is the lower of ~22 kHz and the
2678 Nyquist frequency. Its useful range is about -20 (for a large cut)
2679 to +20 (for a large boost). Beware of clipping when using a positive gain.
2682 Set the filter's central frequency and so can be used
2683 to extend or reduce the frequency range to be boosted or cut.
2684 The default value is @code{3000} Hz.
2687 Set method to specify band-width of filter.
2700 Determine how steep is the filter's shelf transition.
2705 Sinusoidal amplitude modulation.
2707 The filter accepts the following options:
2711 Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
2712 (20 Hz or lower) will result in a tremolo effect.
2713 This filter may also be used as a ring modulator by specifying
2714 a modulation frequency higher than 20 Hz.
2715 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
2718 Depth of modulation as a percentage. Range is 0.0 - 1.0.
2719 Default value is 0.5.
2724 Sinusoidal phase modulation.
2726 The filter accepts the following options:
2730 Modulation frequency in Hertz.
2731 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
2734 Depth of modulation as a percentage. Range is 0.0 - 1.0.
2735 Default value is 0.5.
2740 Adjust the input audio volume.
2742 It accepts the following parameters:
2746 Set audio volume expression.
2748 Output values are clipped to the maximum value.
2750 The output audio volume is given by the relation:
2752 @var{output_volume} = @var{volume} * @var{input_volume}
2755 The default value for @var{volume} is "1.0".
2758 This parameter represents the mathematical precision.
2760 It determines which input sample formats will be allowed, which affects the
2761 precision of the volume scaling.
2765 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
2767 32-bit floating-point; this limits input sample format to FLT. (default)
2769 64-bit floating-point; this limits input sample format to DBL.
2773 Choose the behaviour on encountering ReplayGain side data in input frames.
2777 Remove ReplayGain side data, ignoring its contents (the default).
2780 Ignore ReplayGain side data, but leave it in the frame.
2783 Prefer the track gain, if present.
2786 Prefer the album gain, if present.
2789 @item replaygain_preamp
2790 Pre-amplification gain in dB to apply to the selected replaygain gain.
2792 Default value for @var{replaygain_preamp} is 0.0.
2795 Set when the volume expression is evaluated.
2797 It accepts the following values:
2800 only evaluate expression once during the filter initialization, or
2801 when the @samp{volume} command is sent
2804 evaluate expression for each incoming frame
2807 Default value is @samp{once}.
2810 The volume expression can contain the following parameters.
2814 frame number (starting at zero)
2817 @item nb_consumed_samples
2818 number of samples consumed by the filter
2820 number of samples in the current frame
2822 original frame position in the file
2828 PTS at start of stream
2830 time at start of stream
2836 last set volume value
2839 Note that when @option{eval} is set to @samp{once} only the
2840 @var{sample_rate} and @var{tb} variables are available, all other
2841 variables will evaluate to NAN.
2843 @subsection Commands
2845 This filter supports the following commands:
2848 Modify the volume expression.
2849 The command accepts the same syntax of the corresponding option.
2851 If the specified expression is not valid, it is kept at its current
2853 @item replaygain_noclip
2854 Prevent clipping by limiting the gain applied.
2856 Default value for @var{replaygain_noclip} is 1.
2860 @subsection Examples
2864 Halve the input audio volume:
2868 volume=volume=-6.0206dB
2871 In all the above example the named key for @option{volume} can be
2872 omitted, for example like in:
2878 Increase input audio power by 6 decibels using fixed-point precision:
2880 volume=volume=6dB:precision=fixed
2884 Fade volume after time 10 with an annihilation period of 5 seconds:
2886 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2890 @section volumedetect
2892 Detect the volume of the input video.
2894 The filter has no parameters. The input is not modified. Statistics about
2895 the volume will be printed in the log when the input stream end is reached.
2897 In particular it will show the mean volume (root mean square), maximum
2898 volume (on a per-sample basis), and the beginning of a histogram of the
2899 registered volume values (from the maximum value to a cumulated 1/1000 of
2902 All volumes are in decibels relative to the maximum PCM value.
2904 @subsection Examples
2906 Here is an excerpt of the output:
2908 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2909 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2910 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2911 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2912 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2913 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2914 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2915 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2916 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2922 The mean square energy is approximately -27 dB, or 10^-2.7.
2924 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2926 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2929 In other words, raising the volume by +4 dB does not cause any clipping,
2930 raising it by +5 dB causes clipping for 6 samples, etc.
2932 @c man end AUDIO FILTERS
2934 @chapter Audio Sources
2935 @c man begin AUDIO SOURCES
2937 Below is a description of the currently available audio sources.
2941 Buffer audio frames, and make them available to the filter chain.
2943 This source is mainly intended for a programmatic use, in particular
2944 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2946 It accepts the following parameters:
2950 The timebase which will be used for timestamps of submitted frames. It must be
2951 either a floating-point number or in @var{numerator}/@var{denominator} form.
2954 The sample rate of the incoming audio buffers.
2957 The sample format of the incoming audio buffers.
2958 Either a sample format name or its corresponding integer representation from
2959 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2961 @item channel_layout
2962 The channel layout of the incoming audio buffers.
2963 Either a channel layout name from channel_layout_map in
2964 @file{libavutil/channel_layout.c} or its corresponding integer representation
2965 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2968 The number of channels of the incoming audio buffers.
2969 If both @var{channels} and @var{channel_layout} are specified, then they
2974 @subsection Examples
2977 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2980 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2981 Since the sample format with name "s16p" corresponds to the number
2982 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2985 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2990 Generate an audio signal specified by an expression.
2992 This source accepts in input one or more expressions (one for each
2993 channel), which are evaluated and used to generate a corresponding
2996 This source accepts the following options:
3000 Set the '|'-separated expressions list for each separate channel. In case the
3001 @option{channel_layout} option is not specified, the selected channel layout
3002 depends on the number of provided expressions. Otherwise the last
3003 specified expression is applied to the remaining output channels.
3005 @item channel_layout, c
3006 Set the channel layout. The number of channels in the specified layout
3007 must be equal to the number of specified expressions.
3010 Set the minimum duration of the sourced audio. See
3011 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
3012 for the accepted syntax.
3013 Note that the resulting duration may be greater than the specified
3014 duration, as the generated audio is always cut at the end of a
3017 If not specified, or the expressed duration is negative, the audio is
3018 supposed to be generated forever.
3021 Set the number of samples per channel per each output frame,
3024 @item sample_rate, s
3025 Specify the sample rate, default to 44100.
3028 Each expression in @var{exprs} can contain the following constants:
3032 number of the evaluated sample, starting from 0
3035 time of the evaluated sample expressed in seconds, starting from 0
3042 @subsection Examples
3052 Generate a sin signal with frequency of 440 Hz, set sample rate to
3055 aevalsrc="sin(440*2*PI*t):s=8000"
3059 Generate a two channels signal, specify the channel layout (Front
3060 Center + Back Center) explicitly:
3062 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
3066 Generate white noise:
3068 aevalsrc="-2+random(0)"
3072 Generate an amplitude modulated signal:
3074 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
3078 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
3080 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
3087 The null audio source, return unprocessed audio frames. It is mainly useful
3088 as a template and to be employed in analysis / debugging tools, or as
3089 the source for filters which ignore the input data (for example the sox
3092 This source accepts the following options:
3096 @item channel_layout, cl
3098 Specifies the channel layout, and can be either an integer or a string
3099 representing a channel layout. The default value of @var{channel_layout}
3102 Check the channel_layout_map definition in
3103 @file{libavutil/channel_layout.c} for the mapping between strings and
3104 channel layout values.
3106 @item sample_rate, r
3107 Specifies the sample rate, and defaults to 44100.
3110 Set the number of samples per requested frames.
3114 @subsection Examples
3118 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
3120 anullsrc=r=48000:cl=4
3124 Do the same operation with a more obvious syntax:
3126 anullsrc=r=48000:cl=mono
3130 All the parameters need to be explicitly defined.
3134 Synthesize a voice utterance using the libflite library.
3136 To enable compilation of this filter you need to configure FFmpeg with
3137 @code{--enable-libflite}.
3139 Note that the flite library is not thread-safe.
3141 The filter accepts the following options:
3146 If set to 1, list the names of the available voices and exit
3147 immediately. Default value is 0.
3150 Set the maximum number of samples per frame. Default value is 512.
3153 Set the filename containing the text to speak.
3156 Set the text to speak.
3159 Set the voice to use for the speech synthesis. Default value is
3160 @code{kal}. See also the @var{list_voices} option.
3163 @subsection Examples
3167 Read from file @file{speech.txt}, and synthesize the text using the
3168 standard flite voice:
3170 flite=textfile=speech.txt
3174 Read the specified text selecting the @code{slt} voice:
3176 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3180 Input text to ffmpeg:
3182 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3186 Make @file{ffplay} speak the specified text, using @code{flite} and
3187 the @code{lavfi} device:
3189 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
3193 For more information about libflite, check:
3194 @url{http://www.speech.cs.cmu.edu/flite/}
3198 Generate an audio signal made of a sine wave with amplitude 1/8.
3200 The audio signal is bit-exact.
3202 The filter accepts the following options:
3207 Set the carrier frequency. Default is 440 Hz.
3209 @item beep_factor, b
3210 Enable a periodic beep every second with frequency @var{beep_factor} times
3211 the carrier frequency. Default is 0, meaning the beep is disabled.
3213 @item sample_rate, r
3214 Specify the sample rate, default is 44100.
3217 Specify the duration of the generated audio stream.
3219 @item samples_per_frame
3220 Set the number of samples per output frame.
3222 The expression can contain the following constants:
3226 The (sequential) number of the output audio frame, starting from 0.
3229 The PTS (Presentation TimeStamp) of the output audio frame,
3230 expressed in @var{TB} units.
3233 The PTS of the output audio frame, expressed in seconds.
3236 The timebase of the output audio frames.
3239 Default is @code{1024}.
3242 @subsection Examples
3247 Generate a simple 440 Hz sine wave:
3253 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
3257 sine=frequency=220:beep_factor=4:duration=5
3261 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
3264 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
3268 @c man end AUDIO SOURCES
3270 @chapter Audio Sinks
3271 @c man begin AUDIO SINKS
3273 Below is a description of the currently available audio sinks.
3275 @section abuffersink
3277 Buffer audio frames, and make them available to the end of filter chain.
3279 This sink is mainly intended for programmatic use, in particular
3280 through the interface defined in @file{libavfilter/buffersink.h}
3281 or the options system.
3283 It accepts a pointer to an AVABufferSinkContext structure, which
3284 defines the incoming buffers' formats, to be passed as the opaque
3285 parameter to @code{avfilter_init_filter} for initialization.
3288 Null audio sink; do absolutely nothing with the input audio. It is
3289 mainly useful as a template and for use in analysis / debugging
3292 @c man end AUDIO SINKS
3294 @chapter Video Filters
3295 @c man begin VIDEO FILTERS
3297 When you configure your FFmpeg build, you can disable any of the
3298 existing filters using @code{--disable-filters}.
3299 The configure output will show the video filters included in your
3302 Below is a description of the currently available video filters.
3304 @section alphaextract
3306 Extract the alpha component from the input as a grayscale video. This
3307 is especially useful with the @var{alphamerge} filter.
3311 Add or replace the alpha component of the primary input with the
3312 grayscale value of a second input. This is intended for use with
3313 @var{alphaextract} to allow the transmission or storage of frame
3314 sequences that have alpha in a format that doesn't support an alpha
3317 For example, to reconstruct full frames from a normal YUV-encoded video
3318 and a separate video created with @var{alphaextract}, you might use:
3320 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
3323 Since this filter is designed for reconstruction, it operates on frame
3324 sequences without considering timestamps, and terminates when either
3325 input reaches end of stream. This will cause problems if your encoding
3326 pipeline drops frames. If you're trying to apply an image as an
3327 overlay to a video stream, consider the @var{overlay} filter instead.
3331 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
3332 and libavformat to work. On the other hand, it is limited to ASS (Advanced
3333 Substation Alpha) subtitles files.
3335 This filter accepts the following option in addition to the common options from
3336 the @ref{subtitles} filter:
3340 Set the shaping engine
3342 Available values are:
3345 The default libass shaping engine, which is the best available.
3347 Fast, font-agnostic shaper that can do only substitutions
3349 Slower shaper using OpenType for substitutions and positioning
3352 The default is @code{auto}.
3356 Apply an Adaptive Temporal Averaging Denoiser to the video input.
3358 The filter accepts the following options:
3362 Set threshold A for 1st plane. Default is 0.02.
3363 Valid range is 0 to 0.3.
3366 Set threshold B for 1st plane. Default is 0.04.
3367 Valid range is 0 to 5.
3370 Set threshold A for 2nd plane. Default is 0.02.
3371 Valid range is 0 to 0.3.
3374 Set threshold B for 2nd plane. Default is 0.04.
3375 Valid range is 0 to 5.
3378 Set threshold A for 3rd plane. Default is 0.02.
3379 Valid range is 0 to 0.3.
3382 Set threshold B for 3rd plane. Default is 0.04.
3383 Valid range is 0 to 5.
3385 Threshold A is designed to react on abrupt changes in the input signal and
3386 threshold B is designed to react on continuous changes in the input signal.
3389 Set number of frames filter will use for averaging. Default is 33. Must be odd
3390 number in range [5, 129].
3395 Compute the bounding box for the non-black pixels in the input frame
3398 This filter computes the bounding box containing all the pixels with a
3399 luminance value greater than the minimum allowed value.
3400 The parameters describing the bounding box are printed on the filter
3403 The filter accepts the following option:
3407 Set the minimal luminance value. Default is @code{16}.
3410 @section blackdetect
3412 Detect video intervals that are (almost) completely black. Can be
3413 useful to detect chapter transitions, commercials, or invalid
3414 recordings. Output lines contains the time for the start, end and
3415 duration of the detected black interval expressed in seconds.
3417 In order to display the output lines, you need to set the loglevel at
3418 least to the AV_LOG_INFO value.
3420 The filter accepts the following options:
3423 @item black_min_duration, d
3424 Set the minimum detected black duration expressed in seconds. It must
3425 be a non-negative floating point number.
3427 Default value is 2.0.
3429 @item picture_black_ratio_th, pic_th
3430 Set the threshold for considering a picture "black".
3431 Express the minimum value for the ratio:
3433 @var{nb_black_pixels} / @var{nb_pixels}
3436 for which a picture is considered black.
3437 Default value is 0.98.
3439 @item pixel_black_th, pix_th
3440 Set the threshold for considering a pixel "black".
3442 The threshold expresses the maximum pixel luminance value for which a
3443 pixel is considered "black". The provided value is scaled according to
3444 the following equation:
3446 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
3449 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
3450 the input video format, the range is [0-255] for YUV full-range
3451 formats and [16-235] for YUV non full-range formats.
3453 Default value is 0.10.
3456 The following example sets the maximum pixel threshold to the minimum
3457 value, and detects only black intervals of 2 or more seconds:
3459 blackdetect=d=2:pix_th=0.00
3464 Detect frames that are (almost) completely black. Can be useful to
3465 detect chapter transitions or commercials. Output lines consist of
3466 the frame number of the detected frame, the percentage of blackness,
3467 the position in the file if known or -1 and the timestamp in seconds.
3469 In order to display the output lines, you need to set the loglevel at
3470 least to the AV_LOG_INFO value.
3472 It accepts the following parameters:
3477 The percentage of the pixels that have to be below the threshold; it defaults to
3480 @item threshold, thresh
3481 The threshold below which a pixel value is considered black; it defaults to
3486 @section blend, tblend
3488 Blend two video frames into each other.
3490 The @code{blend} filter takes two input streams and outputs one
3491 stream, the first input is the "top" layer and second input is
3492 "bottom" layer. Output terminates when shortest input terminates.
3494 The @code{tblend} (time blend) filter takes two consecutive frames
3495 from one single stream, and outputs the result obtained by blending
3496 the new frame on top of the old frame.
3498 A description of the accepted options follows.
3506 Set blend mode for specific pixel component or all pixel components in case
3507 of @var{all_mode}. Default value is @code{normal}.
3509 Available values for component modes are:
3547 Set blend opacity for specific pixel component or all pixel components in case
3548 of @var{all_opacity}. Only used in combination with pixel component blend modes.
3555 Set blend expression for specific pixel component or all pixel components in case
3556 of @var{all_expr}. Note that related mode options will be ignored if those are set.
3558 The expressions can use the following variables:
3562 The sequential number of the filtered frame, starting from @code{0}.
3566 the coordinates of the current sample
3570 the width and height of currently filtered plane
3574 Width and height scale depending on the currently filtered plane. It is the
3575 ratio between the corresponding luma plane number of pixels and the current
3576 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
3577 @code{0.5,0.5} for chroma planes.
3580 Time of the current frame, expressed in seconds.
3583 Value of pixel component at current location for first video frame (top layer).
3586 Value of pixel component at current location for second video frame (bottom layer).
3590 Force termination when the shortest input terminates. Default is
3591 @code{0}. This option is only defined for the @code{blend} filter.
3594 Continue applying the last bottom frame after the end of the stream. A value of
3595 @code{0} disable the filter after the last frame of the bottom layer is reached.
3596 Default is @code{1}. This option is only defined for the @code{blend} filter.
3599 @subsection Examples
3603 Apply transition from bottom layer to top layer in first 10 seconds:
3605 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
3609 Apply 1x1 checkerboard effect:
3611 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
3615 Apply uncover left effect:
3617 blend=all_expr='if(gte(N*SW+X,W),A,B)'
3621 Apply uncover down effect:
3623 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
3627 Apply uncover up-left effect:
3629 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
3633 Display differences between the current and the previous frame:
3635 tblend=all_mode=difference128
3641 Apply a boxblur algorithm to the input video.
3643 It accepts the following parameters:
3647 @item luma_radius, lr
3648 @item luma_power, lp
3649 @item chroma_radius, cr
3650 @item chroma_power, cp
3651 @item alpha_radius, ar
3652 @item alpha_power, ap
3656 A description of the accepted options follows.
3659 @item luma_radius, lr
3660 @item chroma_radius, cr
3661 @item alpha_radius, ar
3662 Set an expression for the box radius in pixels used for blurring the
3663 corresponding input plane.
3665 The radius value must be a non-negative number, and must not be
3666 greater than the value of the expression @code{min(w,h)/2} for the
3667 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
3670 Default value for @option{luma_radius} is "2". If not specified,
3671 @option{chroma_radius} and @option{alpha_radius} default to the
3672 corresponding value set for @option{luma_radius}.
3674 The expressions can contain the following constants:
3678 The input width and height in pixels.
3682 The input chroma image width and height in pixels.
3686 The horizontal and vertical chroma subsample values. For example, for the
3687 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
3690 @item luma_power, lp
3691 @item chroma_power, cp
3692 @item alpha_power, ap
3693 Specify how many times the boxblur filter is applied to the
3694 corresponding plane.
3696 Default value for @option{luma_power} is 2. If not specified,
3697 @option{chroma_power} and @option{alpha_power} default to the
3698 corresponding value set for @option{luma_power}.
3700 A value of 0 will disable the effect.
3703 @subsection Examples
3707 Apply a boxblur filter with the luma, chroma, and alpha radii
3710 boxblur=luma_radius=2:luma_power=1
3715 Set the luma radius to 2, and alpha and chroma radius to 0:
3717 boxblur=2:1:cr=0:ar=0
3721 Set the luma and chroma radii to a fraction of the video dimension:
3723 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
3728 YUV colorspace color/chroma keying.
3730 The filter accepts the following options:
3734 The color which will be replaced with transparency.
3737 Similarity percentage with the key color.
3739 0.01 matches only the exact key color, while 1.0 matches everything.
3744 0.0 makes pixels either fully transparent, or not transparent at all.
3746 Higher values result in semi-transparent pixels, with a higher transparency
3747 the more similar the pixels color is to the key color.
3750 Signals that the color passed is already in YUV instead of RGB.
3752 Litteral colors like "green" or "red" don't make sense with this enabled anymore.
3753 This can be used to pass exact YUV values as hexadecimal numbers.
3756 @subsection Examples
3760 Make every green pixel in the input image transparent:
3762 ffmpeg -i input.png -vf chromakey=green out.png
3766 Overlay a greenscreen-video on top of a static black background.
3768 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
3774 Visualize information exported by some codecs.
3776 Some codecs can export information through frames using side-data or other
3777 means. For example, some MPEG based codecs export motion vectors through the
3778 @var{export_mvs} flag in the codec @option{flags2} option.
3780 The filter accepts the following option:
3784 Set motion vectors to visualize.
3786 Available flags for @var{mv} are:
3790 forward predicted MVs of P-frames
3792 forward predicted MVs of B-frames
3794 backward predicted MVs of B-frames
3798 @subsection Examples
3802 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
3804 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
3808 @section colorbalance
3809 Modify intensity of primary colors (red, green and blue) of input frames.
3811 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
3812 regions for the red-cyan, green-magenta or blue-yellow balance.
3814 A positive adjustment value shifts the balance towards the primary color, a negative
3815 value towards the complementary color.
3817 The filter accepts the following options:
3823 Adjust red, green and blue shadows (darkest pixels).
3828 Adjust red, green and blue midtones (medium pixels).
3833 Adjust red, green and blue highlights (brightest pixels).
3835 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3838 @subsection Examples
3842 Add red color cast to shadows:
3849 RGB colorspace color keying.
3851 The filter accepts the following options:
3855 The color which will be replaced with transparency.
3858 Similarity percentage with the key color.
3860 0.01 matches only the exact key color, while 1.0 matches everything.
3865 0.0 makes pixels either fully transparent, or not transparent at all.
3867 Higher values result in semi-transparent pixels, with a higher transparency
3868 the more similar the pixels color is to the key color.
3871 @subsection Examples
3875 Make every green pixel in the input image transparent:
3877 ffmpeg -i input.png -vf colorkey=green out.png
3881 Overlay a greenscreen-video on top of a static background image.
3883 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
3887 @section colorlevels
3889 Adjust video input frames using levels.
3891 The filter accepts the following options:
3898 Adjust red, green, blue and alpha input black point.
3899 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3905 Adjust red, green, blue and alpha input white point.
3906 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
3908 Input levels are used to lighten highlights (bright tones), darken shadows
3909 (dark tones), change the balance of bright and dark tones.
3915 Adjust red, green, blue and alpha output black point.
3916 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
3922 Adjust red, green, blue and alpha output white point.
3923 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
3925 Output levels allows manual selection of a constrained output level range.
3928 @subsection Examples
3932 Make video output darker:
3934 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3940 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3944 Make video output lighter:
3946 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3950 Increase brightness:
3952 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3956 @section colorchannelmixer
3958 Adjust video input frames by re-mixing color channels.
3960 This filter modifies a color channel by adding the values associated to
3961 the other channels of the same pixels. For example if the value to
3962 modify is red, the output value will be:
3964 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3967 The filter accepts the following options:
3974 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3975 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3981 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3982 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3988 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3989 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3995 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3996 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3998 Allowed ranges for options are @code{[-2.0, 2.0]}.
4001 @subsection Examples
4005 Convert source to grayscale:
4007 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
4010 Simulate sepia tones:
4012 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
4016 @section colormatrix
4018 Convert color matrix.
4020 The filter accepts the following options:
4025 Specify the source and destination color matrix. Both values must be
4028 The accepted values are:
4044 For example to convert from BT.601 to SMPTE-240M, use the command:
4046 colormatrix=bt601:smpte240m
4051 Copy the input source unchanged to the output. This is mainly useful for
4056 Crop the input video to given dimensions.
4058 It accepts the following parameters:
4062 The width of the output video. It defaults to @code{iw}.
4063 This expression is evaluated only once during the filter
4064 configuration, or when the @samp{w} or @samp{out_w} command is sent.
4067 The height of the output video. It defaults to @code{ih}.
4068 This expression is evaluated only once during the filter
4069 configuration, or when the @samp{h} or @samp{out_h} command is sent.
4072 The horizontal position, in the input video, of the left edge of the output
4073 video. It defaults to @code{(in_w-out_w)/2}.
4074 This expression is evaluated per-frame.
4077 The vertical position, in the input video, of the top edge of the output video.
4078 It defaults to @code{(in_h-out_h)/2}.
4079 This expression is evaluated per-frame.
4082 If set to 1 will force the output display aspect ratio
4083 to be the same of the input, by changing the output sample aspect
4084 ratio. It defaults to 0.
4087 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
4088 expressions containing the following constants:
4093 The computed values for @var{x} and @var{y}. They are evaluated for
4098 The input width and height.
4102 These are the same as @var{in_w} and @var{in_h}.
4106 The output (cropped) width and height.
4110 These are the same as @var{out_w} and @var{out_h}.
4113 same as @var{iw} / @var{ih}
4116 input sample aspect ratio
4119 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
4123 horizontal and vertical chroma subsample values. For example for the
4124 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4127 The number of the input frame, starting from 0.
4130 the position in the file of the input frame, NAN if unknown
4133 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
4137 The expression for @var{out_w} may depend on the value of @var{out_h},
4138 and the expression for @var{out_h} may depend on @var{out_w}, but they
4139 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
4140 evaluated after @var{out_w} and @var{out_h}.
4142 The @var{x} and @var{y} parameters specify the expressions for the
4143 position of the top-left corner of the output (non-cropped) area. They
4144 are evaluated for each frame. If the evaluated value is not valid, it
4145 is approximated to the nearest valid value.
4147 The expression for @var{x} may depend on @var{y}, and the expression
4148 for @var{y} may depend on @var{x}.
4150 @subsection Examples
4154 Crop area with size 100x100 at position (12,34).
4159 Using named options, the example above becomes:
4161 crop=w=100:h=100:x=12:y=34
4165 Crop the central input area with size 100x100:
4171 Crop the central input area with size 2/3 of the input video:
4173 crop=2/3*in_w:2/3*in_h
4177 Crop the input video central square:
4184 Delimit the rectangle with the top-left corner placed at position
4185 100:100 and the right-bottom corner corresponding to the right-bottom
4186 corner of the input image.
4188 crop=in_w-100:in_h-100:100:100
4192 Crop 10 pixels from the left and right borders, and 20 pixels from
4193 the top and bottom borders
4195 crop=in_w-2*10:in_h-2*20
4199 Keep only the bottom right quarter of the input image:
4201 crop=in_w/2:in_h/2:in_w/2:in_h/2
4205 Crop height for getting Greek harmony:
4207 crop=in_w:1/PHI*in_w
4211 Apply trembling effect:
4213 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)
4217 Apply erratic camera effect depending on timestamp:
4219 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)"
4223 Set x depending on the value of y:
4225 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
4229 @subsection Commands
4231 This filter supports the following commands:
4237 Set width/height of the output video and the horizontal/vertical position
4239 The command accepts the same syntax of the corresponding option.
4241 If the specified expression is not valid, it is kept at its current
4247 Auto-detect the crop size.
4249 It calculates the necessary cropping parameters and prints the
4250 recommended parameters via the logging system. The detected dimensions
4251 correspond to the non-black area of the input video.
4253 It accepts the following parameters:
4258 Set higher black value threshold, which can be optionally specified
4259 from nothing (0) to everything (255 for 8bit based formats). An intensity
4260 value greater to the set value is considered non-black. It defaults to 24.
4261 You can also specify a value between 0.0 and 1.0 which will be scaled depending
4262 on the bitdepth of the pixel format.
4265 The value which the width/height should be divisible by. It defaults to
4266 16. The offset is automatically adjusted to center the video. Use 2 to
4267 get only even dimensions (needed for 4:2:2 video). 16 is best when
4268 encoding to most video codecs.
4270 @item reset_count, reset
4271 Set the counter that determines after how many frames cropdetect will
4272 reset the previously detected largest video area and start over to
4273 detect the current optimal crop area. Default value is 0.
4275 This can be useful when channel logos distort the video area. 0
4276 indicates 'never reset', and returns the largest area encountered during
4283 Apply color adjustments using curves.
4285 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
4286 component (red, green and blue) has its values defined by @var{N} key points
4287 tied from each other using a smooth curve. The x-axis represents the pixel
4288 values from the input frame, and the y-axis the new pixel values to be set for
4291 By default, a component curve is defined by the two points @var{(0;0)} and
4292 @var{(1;1)}. This creates a straight line where each original pixel value is
4293 "adjusted" to its own value, which means no change to the image.
4295 The filter allows you to redefine these two points and add some more. A new
4296 curve (using a natural cubic spline interpolation) will be define to pass
4297 smoothly through all these new coordinates. The new defined points needs to be
4298 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
4299 be in the @var{[0;1]} interval. If the computed curves happened to go outside
4300 the vector spaces, the values will be clipped accordingly.
4302 If there is no key point defined in @code{x=0}, the filter will automatically
4303 insert a @var{(0;0)} point. In the same way, if there is no key point defined
4304 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
4306 The filter accepts the following options:
4310 Select one of the available color presets. This option can be used in addition
4311 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
4312 options takes priority on the preset values.
4313 Available presets are:
4316 @item color_negative
4319 @item increase_contrast
4321 @item linear_contrast
4322 @item medium_contrast
4324 @item strong_contrast
4327 Default is @code{none}.
4329 Set the master key points. These points will define a second pass mapping. It
4330 is sometimes called a "luminance" or "value" mapping. It can be used with
4331 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
4332 post-processing LUT.
4334 Set the key points for the red component.
4336 Set the key points for the green component.
4338 Set the key points for the blue component.
4340 Set the key points for all components (not including master).
4341 Can be used in addition to the other key points component
4342 options. In this case, the unset component(s) will fallback on this
4343 @option{all} setting.
4345 Specify a Photoshop curves file (@code{.acv}) to import the settings from.
4348 To avoid some filtergraph syntax conflicts, each key points list need to be
4349 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
4351 @subsection Examples
4355 Increase slightly the middle level of blue:
4357 curves=blue='0.5/0.58'
4363 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
4365 Here we obtain the following coordinates for each components:
4368 @code{(0;0.11) (0.42;0.51) (1;0.95)}
4370 @code{(0;0) (0.50;0.48) (1;1)}
4372 @code{(0;0.22) (0.49;0.44) (1;0.80)}
4376 The previous example can also be achieved with the associated built-in preset:
4378 curves=preset=vintage
4388 Use a Photoshop preset and redefine the points of the green component:
4390 curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
4396 Denoise frames using 2D DCT (frequency domain filtering).
4398 This filter is not designed for real time.
4400 The filter accepts the following options:
4404 Set the noise sigma constant.
4406 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
4407 coefficient (absolute value) below this threshold with be dropped.
4409 If you need a more advanced filtering, see @option{expr}.
4411 Default is @code{0}.
4414 Set number overlapping pixels for each block. Since the filter can be slow, you
4415 may want to reduce this value, at the cost of a less effective filter and the
4416 risk of various artefacts.
4418 If the overlapping value doesn't permit processing the whole input width or
4419 height, a warning will be displayed and according borders won't be denoised.
4421 Default value is @var{blocksize}-1, which is the best possible setting.
4424 Set the coefficient factor expression.
4426 For each coefficient of a DCT block, this expression will be evaluated as a
4427 multiplier value for the coefficient.
4429 If this is option is set, the @option{sigma} option will be ignored.
4431 The absolute value of the coefficient can be accessed through the @var{c}
4435 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
4436 @var{blocksize}, which is the width and height of the processed blocks.
4438 The default value is @var{3} (8x8) and can be raised to @var{4} for a
4439 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
4440 on the speed processing. Also, a larger block size does not necessarily means a
4444 @subsection Examples
4446 Apply a denoise with a @option{sigma} of @code{4.5}:
4451 The same operation can be achieved using the expression system:
4453 dctdnoiz=e='gte(c, 4.5*3)'
4456 Violent denoise using a block size of @code{16x16}:
4463 Remove banding artifacts from input video.
4464 It works by replacing banded pixels with average value of referenced pixels.
4466 The filter accepts the following options:
4473 Set banding detection threshold for each plane. Default is 0.02.
4474 Valid range is 0.00003 to 0.5.
4475 If difference between current pixel and reference pixel is less than threshold,
4476 it will be considered as banded.
4479 Banding detection range in pixels. Default is 16. If positive, random number
4480 in range 0 to set value will be used. If negative, exact absolute value
4482 The range defines square of four pixels around current pixel.
4485 Set direction in radians from which four pixel will be compared. If positive,
4486 random direction from 0 to set direction will be picked. If negative, exact of
4487 absolute value will be picked. For example direction 0, -PI or -2*PI radians
4488 will pick only pixels on same row and -PI/2 will pick only pixels on same
4492 If enabled, current pixel is compared with average value of all four
4493 surrounding pixels. The default is enabled. If disabled current pixel is
4494 compared with all four surrounding pixels. The pixel is considered banded
4495 if only all four differences with surrounding pixels are less than threshold.
4501 Drop duplicated frames at regular intervals.
4503 The filter accepts the following options:
4507 Set the number of frames from which one will be dropped. Setting this to
4508 @var{N} means one frame in every batch of @var{N} frames will be dropped.
4509 Default is @code{5}.
4512 Set the threshold for duplicate detection. If the difference metric for a frame
4513 is less than or equal to this value, then it is declared as duplicate. Default
4517 Set scene change threshold. Default is @code{15}.
4521 Set the size of the x and y-axis blocks used during metric calculations.
4522 Larger blocks give better noise suppression, but also give worse detection of
4523 small movements. Must be a power of two. Default is @code{32}.
4526 Mark main input as a pre-processed input and activate clean source input
4527 stream. This allows the input to be pre-processed with various filters to help
4528 the metrics calculation while keeping the frame selection lossless. When set to
4529 @code{1}, the first stream is for the pre-processed input, and the second
4530 stream is the clean source from where the kept frames are chosen. Default is
4534 Set whether or not chroma is considered in the metric calculations. Default is
4540 Apply deflate effect to the video.
4542 This filter replaces the pixel by the local(3x3) average by taking into account
4543 only values lower than the pixel.
4545 It accepts the following options:
4552 Limit the maximum change for each plane, default is 65535.
4553 If 0, plane will remain unchanged.
4558 Remove judder produced by partially interlaced telecined content.
4560 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
4561 source was partially telecined content then the output of @code{pullup,dejudder}
4562 will have a variable frame rate. May change the recorded frame rate of the
4563 container. Aside from that change, this filter will not affect constant frame
4566 The option available in this filter is:
4570 Specify the length of the window over which the judder repeats.
4572 Accepts any integer greater than 1. Useful values are:
4576 If the original was telecined from 24 to 30 fps (Film to NTSC).
4579 If the original was telecined from 25 to 30 fps (PAL to NTSC).
4582 If a mixture of the two.
4585 The default is @samp{4}.
4590 Suppress a TV station logo by a simple interpolation of the surrounding
4591 pixels. Just set a rectangle covering the logo and watch it disappear
4592 (and sometimes something even uglier appear - your mileage may vary).
4594 It accepts the following parameters:
4599 Specify the top left corner coordinates of the logo. They must be
4604 Specify the width and height of the logo to clear. They must be
4608 Specify the thickness of the fuzzy edge of the rectangle (added to
4609 @var{w} and @var{h}). The default value is 1. This option is
4610 deprecated, setting higher values should no longer be necessary and
4614 When set to 1, a green rectangle is drawn on the screen to simplify
4615 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
4616 The default value is 0.
4618 The rectangle is drawn on the outermost pixels which will be (partly)
4619 replaced with interpolated values. The values of the next pixels
4620 immediately outside this rectangle in each direction will be used to
4621 compute the interpolated pixel values inside the rectangle.
4625 @subsection Examples
4629 Set a rectangle covering the area with top left corner coordinates 0,0
4630 and size 100x77, and a band of size 10:
4632 delogo=x=0:y=0:w=100:h=77:band=10
4639 Attempt to fix small changes in horizontal and/or vertical shift. This
4640 filter helps remove camera shake from hand-holding a camera, bumping a
4641 tripod, moving on a vehicle, etc.
4643 The filter accepts the following options:
4651 Specify a rectangular area where to limit the search for motion
4653 If desired the search for motion vectors can be limited to a
4654 rectangular area of the frame defined by its top left corner, width
4655 and height. These parameters have the same meaning as the drawbox
4656 filter which can be used to visualise the position of the bounding
4659 This is useful when simultaneous movement of subjects within the frame
4660 might be confused for camera motion by the motion vector search.
4662 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
4663 then the full frame is used. This allows later options to be set
4664 without specifying the bounding box for the motion vector search.
4666 Default - search the whole frame.
4670 Specify the maximum extent of movement in x and y directions in the
4671 range 0-64 pixels. Default 16.
4674 Specify how to generate pixels to fill blanks at the edge of the
4675 frame. Available values are:
4678 Fill zeroes at blank locations
4680 Original image at blank locations
4682 Extruded edge value at blank locations
4684 Mirrored edge at blank locations
4686 Default value is @samp{mirror}.
4689 Specify the blocksize to use for motion search. Range 4-128 pixels,
4693 Specify the contrast threshold for blocks. Only blocks with more than
4694 the specified contrast (difference between darkest and lightest
4695 pixels) will be considered. Range 1-255, default 125.
4698 Specify the search strategy. Available values are:
4701 Set exhaustive search
4703 Set less exhaustive search.
4705 Default value is @samp{exhaustive}.
4708 If set then a detailed log of the motion search is written to the
4712 If set to 1, specify using OpenCL capabilities, only available if
4713 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
4719 Apply an exact inverse of the telecine operation. It requires a predefined
4720 pattern specified using the pattern option which must be the same as that passed
4721 to the telecine filter.
4723 This filter accepts the following options:
4732 The default value is @code{top}.
4736 A string of numbers representing the pulldown pattern you wish to apply.
4737 The default value is @code{23}.
4740 A number representing position of the first frame with respect to the telecine
4741 pattern. This is to be used if the stream is cut. The default value is @code{0}.
4746 Apply dilation effect to the video.
4748 This filter replaces the pixel by the local(3x3) maximum.
4750 It accepts the following options:
4757 Limit the maximum change for each plane, default is 65535.
4758 If 0, plane will remain unchanged.
4761 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
4764 Flags to local 3x3 coordinates maps like this:
4773 Displace pixels as indicated by second and third input stream.
4775 It takes three input streams and outputs one stream, the first input is the
4776 source, and second and third input are displacement maps.
4778 The second input specifies how much to displace pixels along the
4779 x-axis, while the third input specifies how much to displace pixels
4781 If one of displacement map streams terminates, last frame from that
4782 displacement map will be used.
4784 Note that once generated, displacements maps can be reused over and over again.
4786 A description of the accepted options follows.
4790 Set displace behavior for pixels that are out of range.
4792 Available values are:
4795 Missing pixels are replaced by black pixels.
4798 Adjacent pixels will spread out to replace missing pixels.
4801 Out of range pixels are wrapped so they point to pixels of other side.
4803 Default is @samp{smear}.
4807 @subsection Examples
4811 Add ripple effect to rgb input of video size hd720:
4813 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
4817 Add wave effect to rgb input of video size hd720:
4819 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
4825 Draw a colored box on the input image.
4827 It accepts the following parameters:
4832 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
4836 The expressions which specify the width and height of the box; if 0 they are interpreted as
4837 the input width and height. It defaults to 0.
4840 Specify the color of the box to write. For the general syntax of this option,
4841 check the "Color" section in the ffmpeg-utils manual. If the special
4842 value @code{invert} is used, the box edge color is the same as the
4843 video with inverted luma.
4846 The expression which sets the thickness of the box edge. Default value is @code{3}.
4848 See below for the list of accepted constants.
4851 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
4852 following constants:
4856 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
4860 horizontal and vertical chroma subsample values. For example for the
4861 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4865 The input width and height.
4868 The input sample aspect ratio.
4872 The x and y offset coordinates where the box is drawn.
4876 The width and height of the drawn box.
4879 The thickness of the drawn box.
4881 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
4882 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
4886 @subsection Examples
4890 Draw a black box around the edge of the input image:
4896 Draw a box with color red and an opacity of 50%:
4898 drawbox=10:20:200:60:red@@0.5
4901 The previous example can be specified as:
4903 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
4907 Fill the box with pink color:
4909 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
4913 Draw a 2-pixel red 2.40:1 mask:
4915 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
4919 @section drawgraph, adrawgraph
4921 Draw a graph using input video or audio metadata.
4923 It accepts the following parameters:
4927 Set 1st frame metadata key from which metadata values will be used to draw a graph.
4930 Set 1st foreground color expression.
4933 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
4936 Set 2nd foreground color expression.
4939 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
4942 Set 3rd foreground color expression.
4945 Set 4th frame metadata key from which metadata values will be used to draw a graph.
4948 Set 4th foreground color expression.
4951 Set minimal value of metadata value.
4954 Set maximal value of metadata value.
4957 Set graph background color. Default is white.
4962 Available values for mode is:
4969 Default is @code{line}.
4974 Available values for slide is:
4977 Draw new frame when right border is reached.
4980 Replace old columns with new ones.
4983 Scroll from right to left.
4986 Scroll from left to right.
4989 Default is @code{frame}.
4992 Set size of graph video. For the syntax of this option, check the
4993 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
4994 The default value is @code{900x256}.
4996 The foreground color expressions can use the following variables:
4999 Minimal value of metadata value.
5002 Maximal value of metadata value.
5005 Current metadata key value.
5008 The color is defined as 0xAABBGGRR.
5011 Example using metadata from @ref{signalstats} filter:
5013 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
5016 Example using metadata from @ref{ebur128} filter:
5018 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
5023 Draw a grid on the input image.
5025 It accepts the following parameters:
5030 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
5034 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
5035 input width and height, respectively, minus @code{thickness}, so image gets
5036 framed. Default to 0.
5039 Specify the color of the grid. For the general syntax of this option,
5040 check the "Color" section in the ffmpeg-utils manual. If the special
5041 value @code{invert} is used, the grid color is the same as the
5042 video with inverted luma.
5045 The expression which sets the thickness of the grid line. Default value is @code{1}.
5047 See below for the list of accepted constants.
5050 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
5051 following constants:
5055 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
5059 horizontal and vertical chroma subsample values. For example for the
5060 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5064 The input grid cell width and height.
5067 The input sample aspect ratio.
5071 The x and y coordinates of some point of grid intersection (meant to configure offset).
5075 The width and height of the drawn cell.
5078 The thickness of the drawn cell.
5080 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
5081 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
5085 @subsection Examples
5089 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
5091 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
5095 Draw a white 3x3 grid with an opacity of 50%:
5097 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
5104 Draw a text string or text from a specified file on top of a video, using the
5105 libfreetype library.
5107 To enable compilation of this filter, you need to configure FFmpeg with
5108 @code{--enable-libfreetype}.
5109 To enable default font fallback and the @var{font} option you need to
5110 configure FFmpeg with @code{--enable-libfontconfig}.
5111 To enable the @var{text_shaping} option, you need to configure FFmpeg with
5112 @code{--enable-libfribidi}.
5116 It accepts the following parameters:
5121 Used to draw a box around text using the background color.
5122 The value must be either 1 (enable) or 0 (disable).
5123 The default value of @var{box} is 0.
5126 Set the width of the border to be drawn around the box using @var{boxcolor}.
5127 The default value of @var{boxborderw} is 0.
5130 The color to be used for drawing box around text. For the syntax of this
5131 option, check the "Color" section in the ffmpeg-utils manual.
5133 The default value of @var{boxcolor} is "white".
5136 Set the width of the border to be drawn around the text using @var{bordercolor}.
5137 The default value of @var{borderw} is 0.
5140 Set the color to be used for drawing border around text. For the syntax of this
5141 option, check the "Color" section in the ffmpeg-utils manual.
5143 The default value of @var{bordercolor} is "black".
5146 Select how the @var{text} is expanded. Can be either @code{none},
5147 @code{strftime} (deprecated) or
5148 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
5152 If true, check and fix text coords to avoid clipping.
5155 The color to be used for drawing fonts. For the syntax of this option, check
5156 the "Color" section in the ffmpeg-utils manual.
5158 The default value of @var{fontcolor} is "black".
5160 @item fontcolor_expr
5161 String which is expanded the same way as @var{text} to obtain dynamic
5162 @var{fontcolor} value. By default this option has empty value and is not
5163 processed. When this option is set, it overrides @var{fontcolor} option.
5166 The font family to be used for drawing text. By default Sans.
5169 The font file to be used for drawing text. The path must be included.
5170 This parameter is mandatory if the fontconfig support is disabled.
5173 This option does not exist, please see the timeline system
5176 Draw the text applying alpha blending. The value can
5177 be either a number between 0.0 and 1.0
5178 The expression accepts the same variables @var{x, y} do.
5179 The default value is 1.
5180 Please see fontcolor_expr
5183 The font size to be used for drawing text.
5184 The default value of @var{fontsize} is 16.
5187 If set to 1, attempt to shape the text (for example, reverse the order of
5188 right-to-left text and join Arabic characters) before drawing it.
5189 Otherwise, just draw the text exactly as given.
5190 By default 1 (if supported).
5193 The flags to be used for loading the fonts.
5195 The flags map the corresponding flags supported by libfreetype, and are
5196 a combination of the following values:
5203 @item vertical_layout
5204 @item force_autohint
5207 @item ignore_global_advance_width
5209 @item ignore_transform
5215 Default value is "default".
5217 For more information consult the documentation for the FT_LOAD_*
5221 The color to be used for drawing a shadow behind the drawn text. For the
5222 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
5224 The default value of @var{shadowcolor} is "black".
5228 The x and y offsets for the text shadow position with respect to the
5229 position of the text. They can be either positive or negative
5230 values. The default value for both is "0".
5233 The starting frame number for the n/frame_num variable. The default value
5237 The size in number of spaces to use for rendering the tab.
5241 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
5242 format. It can be used with or without text parameter. @var{timecode_rate}
5243 option must be specified.
5245 @item timecode_rate, rate, r
5246 Set the timecode frame rate (timecode only).
5249 The text string to be drawn. The text must be a sequence of UTF-8
5251 This parameter is mandatory if no file is specified with the parameter
5255 A text file containing text to be drawn. The text must be a sequence
5256 of UTF-8 encoded characters.
5258 This parameter is mandatory if no text string is specified with the
5259 parameter @var{text}.
5261 If both @var{text} and @var{textfile} are specified, an error is thrown.
5264 If set to 1, the @var{textfile} will be reloaded before each frame.
5265 Be sure to update it atomically, or it may be read partially, or even fail.
5269 The expressions which specify the offsets where text will be drawn
5270 within the video frame. They are relative to the top/left border of the
5273 The default value of @var{x} and @var{y} is "0".
5275 See below for the list of accepted constants and functions.
5278 The parameters for @var{x} and @var{y} are expressions containing the
5279 following constants and functions:
5283 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
5287 horizontal and vertical chroma subsample values. For example for the
5288 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5291 the height of each text line
5299 @item max_glyph_a, ascent
5300 the maximum distance from the baseline to the highest/upper grid
5301 coordinate used to place a glyph outline point, for all the rendered
5303 It is a positive value, due to the grid's orientation with the Y axis
5306 @item max_glyph_d, descent
5307 the maximum distance from the baseline to the lowest grid coordinate
5308 used to place a glyph outline point, for all the rendered glyphs.
5309 This is a negative value, due to the grid's orientation, with the Y axis
5313 maximum glyph height, that is the maximum height for all the glyphs
5314 contained in the rendered text, it is equivalent to @var{ascent} -
5318 maximum glyph width, that is the maximum width for all the glyphs
5319 contained in the rendered text
5322 the number of input frame, starting from 0
5324 @item rand(min, max)
5325 return a random number included between @var{min} and @var{max}
5328 The input sample aspect ratio.
5331 timestamp expressed in seconds, NAN if the input timestamp is unknown
5334 the height of the rendered text
5337 the width of the rendered text
5341 the x and y offset coordinates where the text is drawn.
5343 These parameters allow the @var{x} and @var{y} expressions to refer
5344 each other, so you can for example specify @code{y=x/dar}.
5347 @anchor{drawtext_expansion}
5348 @subsection Text expansion
5350 If @option{expansion} is set to @code{strftime},
5351 the filter recognizes strftime() sequences in the provided text and
5352 expands them accordingly. Check the documentation of strftime(). This
5353 feature is deprecated.
5355 If @option{expansion} is set to @code{none}, the text is printed verbatim.
5357 If @option{expansion} is set to @code{normal} (which is the default),
5358 the following expansion mechanism is used.
5360 The backslash character @samp{\}, followed by any character, always expands to
5361 the second character.
5363 Sequence of the form @code{%@{...@}} are expanded. The text between the
5364 braces is a function name, possibly followed by arguments separated by ':'.
5365 If the arguments contain special characters or delimiters (':' or '@}'),
5366 they should be escaped.
5368 Note that they probably must also be escaped as the value for the
5369 @option{text} option in the filter argument string and as the filter
5370 argument in the filtergraph description, and possibly also for the shell,
5371 that makes up to four levels of escaping; using a text file avoids these
5374 The following functions are available:
5379 The expression evaluation result.
5381 It must take one argument specifying the expression to be evaluated,
5382 which accepts the same constants and functions as the @var{x} and
5383 @var{y} values. Note that not all constants should be used, for
5384 example the text size is not known when evaluating the expression, so
5385 the constants @var{text_w} and @var{text_h} will have an undefined
5388 @item expr_int_format, eif
5389 Evaluate the expression's value and output as formatted integer.
5391 The first argument is the expression to be evaluated, just as for the @var{expr} function.
5392 The second argument specifies the output format. Allowed values are @samp{x},
5393 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
5394 @code{printf} function.
5395 The third parameter is optional and sets the number of positions taken by the output.
5396 It can be used to add padding with zeros from the left.
5399 The time at which the filter is running, expressed in UTC.
5400 It can accept an argument: a strftime() format string.
5403 The time at which the filter is running, expressed in the local time zone.
5404 It can accept an argument: a strftime() format string.
5407 Frame metadata. It must take one argument specifying metadata key.
5410 The frame number, starting from 0.
5413 A 1 character description of the current picture type.
5416 The timestamp of the current frame.
5417 It can take up to three arguments.
5419 The first argument is the format of the timestamp; it defaults to @code{flt}
5420 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
5421 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
5422 @code{gmtime} stands for the timestamp of the frame formatted as UTC time;
5423 @code{localtime} stands for the timestamp of the frame formatted as
5424 local time zone time.
5426 The second argument is an offset added to the timestamp.
5428 If the format is set to @code{localtime} or @code{gmtime},
5429 a third argument may be supplied: a strftime() format string.
5430 By default, @var{YYYY-MM-DD HH:MM:SS} format will be used.
5433 @subsection Examples
5437 Draw "Test Text" with font FreeSerif, using the default values for the
5438 optional parameters.
5441 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
5445 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
5446 and y=50 (counting from the top-left corner of the screen), text is
5447 yellow with a red box around it. Both the text and the box have an
5451 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
5452 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
5455 Note that the double quotes are not necessary if spaces are not used
5456 within the parameter list.
5459 Show the text at the center of the video frame:
5461 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
5465 Show a text line sliding from right to left in the last row of the video
5466 frame. The file @file{LONG_LINE} is assumed to contain a single line
5469 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
5473 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
5475 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
5479 Draw a single green letter "g", at the center of the input video.
5480 The glyph baseline is placed at half screen height.
5482 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
5486 Show text for 1 second every 3 seconds:
5488 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
5492 Use fontconfig to set the font. Note that the colons need to be escaped.
5494 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
5498 Print the date of a real-time encoding (see strftime(3)):
5500 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
5504 Show text fading in and out (appearing/disappearing):
5507 DS=1.0 # display start
5508 DE=10.0 # display end
5509 FID=1.5 # fade in duration
5510 FOD=5 # fade out duration
5511 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 @}"
5516 For more information about libfreetype, check:
5517 @url{http://www.freetype.org/}.
5519 For more information about fontconfig, check:
5520 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
5522 For more information about libfribidi, check:
5523 @url{http://fribidi.org/}.
5527 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
5529 The filter accepts the following options:
5534 Set low and high threshold values used by the Canny thresholding
5537 The high threshold selects the "strong" edge pixels, which are then
5538 connected through 8-connectivity with the "weak" edge pixels selected
5539 by the low threshold.
5541 @var{low} and @var{high} threshold values must be chosen in the range
5542 [0,1], and @var{low} should be lesser or equal to @var{high}.
5544 Default value for @var{low} is @code{20/255}, and default value for @var{high}
5548 Define the drawing mode.
5552 Draw white/gray wires on black background.
5555 Mix the colors to create a paint/cartoon effect.
5558 Default value is @var{wires}.
5561 @subsection Examples
5565 Standard edge detection with custom values for the hysteresis thresholding:
5567 edgedetect=low=0.1:high=0.4
5571 Painting effect without thresholding:
5573 edgedetect=mode=colormix:high=0
5578 Set brightness, contrast, saturation and approximate gamma adjustment.
5580 The filter accepts the following options:
5584 Set the contrast expression. The value must be a float value in range
5585 @code{-2.0} to @code{2.0}. The default value is "1".
5588 Set the brightness expression. The value must be a float value in
5589 range @code{-1.0} to @code{1.0}. The default value is "0".
5592 Set the saturation expression. The value must be a float in
5593 range @code{0.0} to @code{3.0}. The default value is "1".
5596 Set the gamma expression. The value must be a float in range
5597 @code{0.1} to @code{10.0}. The default value is "1".
5600 Set the gamma expression for red. The value must be a float in
5601 range @code{0.1} to @code{10.0}. The default value is "1".
5604 Set the gamma expression for green. The value must be a float in range
5605 @code{0.1} to @code{10.0}. The default value is "1".
5608 Set the gamma expression for blue. 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 weight expression. It can be used to reduce the effect
5613 of a high gamma value on bright image areas, e.g. keep them from
5614 getting overamplified and just plain white. The value must be a float
5615 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
5616 gamma correction all the way down while @code{1.0} leaves it at its
5617 full strength. Default is "1".
5620 Set when the expressions for brightness, contrast, saturation and
5621 gamma expressions are evaluated.
5623 It accepts the following values:
5626 only evaluate expressions once during the filter initialization or
5627 when a command is processed
5630 evaluate expressions for each incoming frame
5633 Default value is @samp{init}.
5636 The expressions accept the following parameters:
5639 frame count of the input frame starting from 0
5642 byte position of the corresponding packet in the input file, NAN if
5646 frame rate of the input video, NAN if the input frame rate is unknown
5649 timestamp expressed in seconds, NAN if the input timestamp is unknown
5652 @subsection Commands
5653 The filter supports the following commands:
5657 Set the contrast expression.
5660 Set the brightness expression.
5663 Set the saturation expression.
5666 Set the gamma expression.
5669 Set the gamma_r expression.
5672 Set gamma_g expression.
5675 Set gamma_b expression.
5678 Set gamma_weight expression.
5680 The command accepts the same syntax of the corresponding option.
5682 If the specified expression is not valid, it is kept at its current
5689 Apply erosion effect to the video.
5691 This filter replaces the pixel by the local(3x3) minimum.
5693 It accepts the following options:
5700 Limit the maximum change for each plane, default is 65535.
5701 If 0, plane will remain unchanged.
5704 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
5707 Flags to local 3x3 coordinates maps like this:
5714 @section extractplanes
5716 Extract color channel components from input video stream into
5717 separate grayscale video streams.
5719 The filter accepts the following option:
5723 Set plane(s) to extract.
5725 Available values for planes are:
5736 Choosing planes not available in the input will result in an error.
5737 That means you cannot select @code{r}, @code{g}, @code{b} planes
5738 with @code{y}, @code{u}, @code{v} planes at same time.
5741 @subsection Examples
5745 Extract luma, u and v color channel component from input video frame
5746 into 3 grayscale outputs:
5748 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
5754 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
5756 For each input image, the filter will compute the optimal mapping from
5757 the input to the output given the codebook length, that is the number
5758 of distinct output colors.
5760 This filter accepts the following options.
5763 @item codebook_length, l
5764 Set codebook length. The value must be a positive integer, and
5765 represents the number of distinct output colors. Default value is 256.
5768 Set the maximum number of iterations to apply for computing the optimal
5769 mapping. The higher the value the better the result and the higher the
5770 computation time. Default value is 1.
5773 Set a random seed, must be an integer included between 0 and
5774 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
5775 will try to use a good random seed on a best effort basis.
5778 Set pal8 output pixel format. This option does not work with codebook
5779 length greater than 256.
5784 Apply a fade-in/out effect to the input video.
5786 It accepts the following parameters:
5790 The effect type can be either "in" for a fade-in, or "out" for a fade-out
5792 Default is @code{in}.
5794 @item start_frame, s
5795 Specify the number of the frame to start applying the fade
5796 effect at. Default is 0.
5799 The number of frames that the fade effect lasts. At the end of the
5800 fade-in effect, the output video will have the same intensity as the input video.
5801 At the end of the fade-out transition, the output video will be filled with the
5802 selected @option{color}.
5806 If set to 1, fade only alpha channel, if one exists on the input.
5809 @item start_time, st
5810 Specify the timestamp (in seconds) of the frame to start to apply the fade
5811 effect. If both start_frame and start_time are specified, the fade will start at
5812 whichever comes last. Default is 0.
5815 The number of seconds for which the fade effect has to last. At the end of the
5816 fade-in effect the output video will have the same intensity as the input video,
5817 at the end of the fade-out transition the output video will be filled with the
5818 selected @option{color}.
5819 If both duration and nb_frames are specified, duration is used. Default is 0
5820 (nb_frames is used by default).
5823 Specify the color of the fade. Default is "black".
5826 @subsection Examples
5830 Fade in the first 30 frames of video:
5835 The command above is equivalent to:
5841 Fade out the last 45 frames of a 200-frame video:
5844 fade=type=out:start_frame=155:nb_frames=45
5848 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
5850 fade=in:0:25, fade=out:975:25
5854 Make the first 5 frames yellow, then fade in from frame 5-24:
5856 fade=in:5:20:color=yellow
5860 Fade in alpha over first 25 frames of video:
5862 fade=in:0:25:alpha=1
5866 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
5868 fade=t=in:st=5.5:d=0.5
5874 Apply arbitrary expressions to samples in frequency domain
5878 Adjust the dc value (gain) of the luma plane of the image. The filter
5879 accepts an integer value in range @code{0} to @code{1000}. The default
5880 value is set to @code{0}.
5883 Adjust the dc value (gain) of the 1st chroma plane of the image. The
5884 filter accepts an integer value in range @code{0} to @code{1000}. The
5885 default value is set to @code{0}.
5888 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
5889 filter accepts an integer value in range @code{0} to @code{1000}. The
5890 default value is set to @code{0}.
5893 Set the frequency domain weight expression for the luma plane.
5896 Set the frequency domain weight expression for the 1st chroma plane.
5899 Set the frequency domain weight expression for the 2nd chroma plane.
5901 The filter accepts the following variables:
5904 The coordinates of the current sample.
5908 The width and height of the image.
5911 @subsection Examples
5917 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
5923 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
5929 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
5936 Extract a single field from an interlaced image using stride
5937 arithmetic to avoid wasting CPU time. The output frames are marked as
5940 The filter accepts the following options:
5944 Specify whether to extract the top (if the value is @code{0} or
5945 @code{top}) or the bottom field (if the value is @code{1} or
5951 Field matching filter for inverse telecine. It is meant to reconstruct the
5952 progressive frames from a telecined stream. The filter does not drop duplicated
5953 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
5954 followed by a decimation filter such as @ref{decimate} in the filtergraph.
5956 The separation of the field matching and the decimation is notably motivated by
5957 the possibility of inserting a de-interlacing filter fallback between the two.
5958 If the source has mixed telecined and real interlaced content,
5959 @code{fieldmatch} will not be able to match fields for the interlaced parts.
5960 But these remaining combed frames will be marked as interlaced, and thus can be
5961 de-interlaced by a later filter such as @ref{yadif} before decimation.
5963 In addition to the various configuration options, @code{fieldmatch} can take an
5964 optional second stream, activated through the @option{ppsrc} option. If
5965 enabled, the frames reconstruction will be based on the fields and frames from
5966 this second stream. This allows the first input to be pre-processed in order to
5967 help the various algorithms of the filter, while keeping the output lossless
5968 (assuming the fields are matched properly). Typically, a field-aware denoiser,
5969 or brightness/contrast adjustments can help.
5971 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
5972 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
5973 which @code{fieldmatch} is based on. While the semantic and usage are very
5974 close, some behaviour and options names can differ.
5976 The @ref{decimate} filter currently only works for constant frame rate input.
5977 If your input has mixed telecined (30fps) and progressive content with a lower
5978 framerate like 24fps use the following filterchain to produce the necessary cfr
5979 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
5981 The filter accepts the following options:
5985 Specify the assumed field order of the input stream. Available values are:
5989 Auto detect parity (use FFmpeg's internal parity value).
5991 Assume bottom field first.
5993 Assume top field first.
5996 Note that it is sometimes recommended not to trust the parity announced by the
5999 Default value is @var{auto}.
6002 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
6003 sense that it won't risk creating jerkiness due to duplicate frames when
6004 possible, but if there are bad edits or blended fields it will end up
6005 outputting combed frames when a good match might actually exist. On the other
6006 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
6007 but will almost always find a good frame if there is one. The other values are
6008 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
6009 jerkiness and creating duplicate frames versus finding good matches in sections
6010 with bad edits, orphaned fields, blended fields, etc.
6012 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
6014 Available values are:
6018 2-way matching (p/c)
6020 2-way matching, and trying 3rd match if still combed (p/c + n)
6022 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
6024 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
6025 still combed (p/c + n + u/b)
6027 3-way matching (p/c/n)
6029 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
6030 detected as combed (p/c/n + u/b)
6033 The parenthesis at the end indicate the matches that would be used for that
6034 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
6037 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
6040 Default value is @var{pc_n}.
6043 Mark the main input stream as a pre-processed input, and enable the secondary
6044 input stream as the clean source to pick the fields from. See the filter
6045 introduction for more details. It is similar to the @option{clip2} feature from
6048 Default value is @code{0} (disabled).
6051 Set the field to match from. It is recommended to set this to the same value as
6052 @option{order} unless you experience matching failures with that setting. In
6053 certain circumstances changing the field that is used to match from can have a
6054 large impact on matching performance. Available values are:
6058 Automatic (same value as @option{order}).
6060 Match from the bottom field.
6062 Match from the top field.
6065 Default value is @var{auto}.
6068 Set whether or not chroma is included during the match comparisons. In most
6069 cases it is recommended to leave this enabled. You should set this to @code{0}
6070 only if your clip has bad chroma problems such as heavy rainbowing or other
6071 artifacts. Setting this to @code{0} could also be used to speed things up at
6072 the cost of some accuracy.
6074 Default value is @code{1}.
6078 These define an exclusion band which excludes the lines between @option{y0} and
6079 @option{y1} from being included in the field matching decision. An exclusion
6080 band can be used to ignore subtitles, a logo, or other things that may
6081 interfere with the matching. @option{y0} sets the starting scan line and
6082 @option{y1} sets the ending line; all lines in between @option{y0} and
6083 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
6084 @option{y0} and @option{y1} to the same value will disable the feature.
6085 @option{y0} and @option{y1} defaults to @code{0}.
6088 Set the scene change detection threshold as a percentage of maximum change on
6089 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
6090 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
6091 @option{scthresh} is @code{[0.0, 100.0]}.
6093 Default value is @code{12.0}.
6096 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
6097 account the combed scores of matches when deciding what match to use as the
6098 final match. Available values are:
6102 No final matching based on combed scores.
6104 Combed scores are only used when a scene change is detected.
6106 Use combed scores all the time.
6109 Default is @var{sc}.
6112 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
6113 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
6114 Available values are:
6118 No forced calculation.
6120 Force p/c/n calculations.
6122 Force p/c/n/u/b calculations.
6125 Default value is @var{none}.
6128 This is the area combing threshold used for combed frame detection. This
6129 essentially controls how "strong" or "visible" combing must be to be detected.
6130 Larger values mean combing must be more visible and smaller values mean combing
6131 can be less visible or strong and still be detected. Valid settings are from
6132 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
6133 be detected as combed). This is basically a pixel difference value. A good
6134 range is @code{[8, 12]}.
6136 Default value is @code{9}.
6139 Sets whether or not chroma is considered in the combed frame decision. Only
6140 disable this if your source has chroma problems (rainbowing, etc.) that are
6141 causing problems for the combed frame detection with chroma enabled. Actually,
6142 using @option{chroma}=@var{0} is usually more reliable, except for the case
6143 where there is chroma only combing in the source.
6145 Default value is @code{0}.
6149 Respectively set the x-axis and y-axis size of the window used during combed
6150 frame detection. This has to do with the size of the area in which
6151 @option{combpel} pixels are required to be detected as combed for a frame to be
6152 declared combed. See the @option{combpel} parameter description for more info.
6153 Possible values are any number that is a power of 2 starting at 4 and going up
6156 Default value is @code{16}.
6159 The number of combed pixels inside any of the @option{blocky} by
6160 @option{blockx} size blocks on the frame for the frame to be detected as
6161 combed. While @option{cthresh} controls how "visible" the combing must be, this
6162 setting controls "how much" combing there must be in any localized area (a
6163 window defined by the @option{blockx} and @option{blocky} settings) on the
6164 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
6165 which point no frames will ever be detected as combed). This setting is known
6166 as @option{MI} in TFM/VFM vocabulary.
6168 Default value is @code{80}.
6171 @anchor{p/c/n/u/b meaning}
6172 @subsection p/c/n/u/b meaning
6174 @subsubsection p/c/n
6176 We assume the following telecined stream:
6179 Top fields: 1 2 2 3 4
6180 Bottom fields: 1 2 3 4 4
6183 The numbers correspond to the progressive frame the fields relate to. Here, the
6184 first two frames are progressive, the 3rd and 4th are combed, and so on.
6186 When @code{fieldmatch} is configured to run a matching from bottom
6187 (@option{field}=@var{bottom}) this is how this input stream get transformed:
6192 B 1 2 3 4 4 <-- matching reference
6201 As a result of the field matching, we can see that some frames get duplicated.
6202 To perform a complete inverse telecine, you need to rely on a decimation filter
6203 after this operation. See for instance the @ref{decimate} filter.
6205 The same operation now matching from top fields (@option{field}=@var{top})
6210 T 1 2 2 3 4 <-- matching reference
6220 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
6221 basically, they refer to the frame and field of the opposite parity:
6224 @item @var{p} matches the field of the opposite parity in the previous frame
6225 @item @var{c} matches the field of the opposite parity in the current frame
6226 @item @var{n} matches the field of the opposite parity in the next frame
6231 The @var{u} and @var{b} matching are a bit special in the sense that they match
6232 from the opposite parity flag. In the following examples, we assume that we are
6233 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
6234 'x' is placed above and below each matched fields.
6236 With bottom matching (@option{field}=@var{bottom}):
6241 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
6242 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
6250 With top matching (@option{field}=@var{top}):
6255 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
6256 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
6264 @subsection Examples
6266 Simple IVTC of a top field first telecined stream:
6268 fieldmatch=order=tff:combmatch=none, decimate
6271 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
6273 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
6278 Transform the field order of the input video.
6280 It accepts the following parameters:
6285 The output field order. Valid values are @var{tff} for top field first or @var{bff}
6286 for bottom field first.
6289 The default value is @samp{tff}.
6291 The transformation is done by shifting the picture content up or down
6292 by one line, and filling the remaining line with appropriate picture content.
6293 This method is consistent with most broadcast field order converters.
6295 If the input video is not flagged as being interlaced, or it is already
6296 flagged as being of the required output field order, then this filter does
6297 not alter the incoming video.
6299 It is very useful when converting to or from PAL DV material,
6300 which is bottom field first.
6304 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
6309 Buffer input images and send them when they are requested.
6311 It is mainly useful when auto-inserted by the libavfilter
6314 It does not take parameters.
6318 Find a rectangular object
6320 It accepts the following options:
6324 Filepath of the object image, needs to be in gray8.
6327 Detection threshold, default is 0.5.
6330 Number of mipmaps, default is 3.
6332 @item xmin, ymin, xmax, ymax
6333 Specifies the rectangle in which to search.
6336 @subsection Examples
6340 Generate a representative palette of a given video using @command{ffmpeg}:
6342 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
6348 Cover a rectangular object
6350 It accepts the following options:
6354 Filepath of the optional cover image, needs to be in yuv420.
6359 It accepts the following values:
6362 cover it by the supplied image
6364 cover it by interpolating the surrounding pixels
6367 Default value is @var{blur}.
6370 @subsection Examples
6374 Generate a representative palette of a given video using @command{ffmpeg}:
6376 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
6383 Convert the input video to one of the specified pixel formats.
6384 Libavfilter will try to pick one that is suitable as input to
6387 It accepts the following parameters:
6391 A '|'-separated list of pixel format names, such as
6392 "pix_fmts=yuv420p|monow|rgb24".
6396 @subsection Examples
6400 Convert the input video to the @var{yuv420p} format
6402 format=pix_fmts=yuv420p
6405 Convert the input video to any of the formats in the list
6407 format=pix_fmts=yuv420p|yuv444p|yuv410p
6414 Convert the video to specified constant frame rate by duplicating or dropping
6415 frames as necessary.
6417 It accepts the following parameters:
6421 The desired output frame rate. The default is @code{25}.
6426 Possible values are:
6429 zero round towards 0
6433 round towards -infinity
6435 round towards +infinity
6439 The default is @code{near}.
6442 Assume the first PTS should be the given value, in seconds. This allows for
6443 padding/trimming at the start of stream. By default, no assumption is made
6444 about the first frame's expected PTS, so no padding or trimming is done.
6445 For example, this could be set to 0 to pad the beginning with duplicates of
6446 the first frame if a video stream starts after the audio stream or to trim any
6447 frames with a negative PTS.
6451 Alternatively, the options can be specified as a flat string:
6452 @var{fps}[:@var{round}].
6454 See also the @ref{setpts} filter.
6456 @subsection Examples
6460 A typical usage in order to set the fps to 25:
6466 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
6468 fps=fps=film:round=near
6474 Pack two different video streams into a stereoscopic video, setting proper
6475 metadata on supported codecs. The two views should have the same size and
6476 framerate and processing will stop when the shorter video ends. Please note
6477 that you may conveniently adjust view properties with the @ref{scale} and
6480 It accepts the following parameters:
6484 The desired packing format. Supported values are:
6489 The views are next to each other (default).
6492 The views are on top of each other.
6495 The views are packed by line.
6498 The views are packed by column.
6501 The views are temporally interleaved.
6510 # Convert left and right views into a frame-sequential video
6511 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
6513 # Convert views into a side-by-side video with the same output resolution as the input
6514 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
6519 Change the frame rate by interpolating new video output frames from the source
6522 This filter is not designed to function correctly with interlaced media. If
6523 you wish to change the frame rate of interlaced media then you are required
6524 to deinterlace before this filter and re-interlace after this filter.
6526 A description of the accepted options follows.
6530 Specify the output frames per second. This option can also be specified
6531 as a value alone. The default is @code{50}.
6534 Specify the start of a range where the output frame will be created as a
6535 linear interpolation of two frames. The range is [@code{0}-@code{255}],
6536 the default is @code{15}.
6539 Specify the end of a range where the output frame will be created as a
6540 linear interpolation of two frames. The range is [@code{0}-@code{255}],
6541 the default is @code{240}.
6544 Specify the level at which a scene change is detected as a value between
6545 0 and 100 to indicate a new scene; a low value reflects a low
6546 probability for the current frame to introduce a new scene, while a higher
6547 value means the current frame is more likely to be one.
6548 The default is @code{7}.
6551 Specify flags influencing the filter process.
6553 Available value for @var{flags} is:
6556 @item scene_change_detect, scd
6557 Enable scene change detection using the value of the option @var{scene}.
6558 This flag is enabled by default.
6564 Select one frame every N-th frame.
6566 This filter accepts the following option:
6569 Select frame after every @code{step} frames.
6570 Allowed values are positive integers higher than 0. Default value is @code{1}.
6576 Apply a frei0r effect to the input video.
6578 To enable the compilation of this filter, you need to install the frei0r
6579 header and configure FFmpeg with @code{--enable-frei0r}.
6581 It accepts the following parameters:
6586 The name of the frei0r effect to load. If the environment variable
6587 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
6588 directories specified by the colon-separated list in @env{FREIOR_PATH}.
6589 Otherwise, the standard frei0r paths are searched, in this order:
6590 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
6591 @file{/usr/lib/frei0r-1/}.
6594 A '|'-separated list of parameters to pass to the frei0r effect.
6598 A frei0r effect parameter can be a boolean (its value is either
6599 "y" or "n"), a double, a color (specified as
6600 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
6601 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
6602 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
6603 @var{X} and @var{Y} are floating point numbers) and/or a string.
6605 The number and types of parameters depend on the loaded effect. If an
6606 effect parameter is not specified, the default value is set.
6608 @subsection Examples
6612 Apply the distort0r effect, setting the first two double parameters:
6614 frei0r=filter_name=distort0r:filter_params=0.5|0.01
6618 Apply the colordistance effect, taking a color as the first parameter:
6620 frei0r=colordistance:0.2/0.3/0.4
6621 frei0r=colordistance:violet
6622 frei0r=colordistance:0x112233
6626 Apply the perspective effect, specifying the top left and top right image
6629 frei0r=perspective:0.2/0.2|0.8/0.2
6633 For more information, see
6634 @url{http://frei0r.dyne.org}
6638 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
6640 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
6641 processing filter, one of them is performed once per block, not per pixel.
6642 This allows for much higher speed.
6644 The filter accepts the following options:
6648 Set quality. This option defines the number of levels for averaging. It accepts
6649 an integer in the range 4-5. Default value is @code{4}.
6652 Force a constant quantization parameter. It accepts an integer in range 0-63.
6653 If not set, the filter will use the QP from the video stream (if available).
6656 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
6657 more details but also more artifacts, while higher values make the image smoother
6658 but also blurrier. Default value is @code{0} − PSNR optimal.
6661 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
6662 option may cause flicker since the B-Frames have often larger QP. Default is
6663 @code{0} (not enabled).
6669 The filter accepts the following options:
6673 Set the luminance expression.
6675 Set the chrominance blue expression.
6677 Set the chrominance red expression.
6679 Set the alpha expression.
6681 Set the red expression.
6683 Set the green expression.
6685 Set the blue expression.
6688 The colorspace is selected according to the specified options. If one
6689 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
6690 options is specified, the filter will automatically select a YCbCr
6691 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
6692 @option{blue_expr} options is specified, it will select an RGB
6695 If one of the chrominance expression is not defined, it falls back on the other
6696 one. If no alpha expression is specified it will evaluate to opaque value.
6697 If none of chrominance expressions are specified, they will evaluate
6698 to the luminance expression.
6700 The expressions can use the following variables and functions:
6704 The sequential number of the filtered frame, starting from @code{0}.
6708 The coordinates of the current sample.
6712 The width and height of the image.
6716 Width and height scale depending on the currently filtered plane. It is the
6717 ratio between the corresponding luma plane number of pixels and the current
6718 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
6719 @code{0.5,0.5} for chroma planes.
6722 Time of the current frame, expressed in seconds.
6725 Return the value of the pixel at location (@var{x},@var{y}) of the current
6729 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
6733 Return the value of the pixel at location (@var{x},@var{y}) of the
6734 blue-difference chroma plane. Return 0 if there is no such plane.
6737 Return the value of the pixel at location (@var{x},@var{y}) of the
6738 red-difference chroma plane. Return 0 if there is no such plane.
6743 Return the value of the pixel at location (@var{x},@var{y}) of the
6744 red/green/blue component. Return 0 if there is no such component.
6747 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
6748 plane. Return 0 if there is no such plane.
6751 For functions, if @var{x} and @var{y} are outside the area, the value will be
6752 automatically clipped to the closer edge.
6754 @subsection Examples
6758 Flip the image horizontally:
6764 Generate a bidimensional sine wave, with angle @code{PI/3} and a
6765 wavelength of 100 pixels:
6767 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
6771 Generate a fancy enigmatic moving light:
6773 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
6777 Generate a quick emboss effect:
6779 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
6783 Modify RGB components depending on pixel position:
6785 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
6789 Create a radial gradient that is the same size as the input (also see
6790 the @ref{vignette} filter):
6792 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
6796 Create a linear gradient to use as a mask for another filter, then
6797 compose with @ref{overlay}. In this example the video will gradually
6798 become more blurry from the top to the bottom of the y-axis as defined
6799 by the linear gradient:
6801 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
6807 Fix the banding artifacts that are sometimes introduced into nearly flat
6808 regions by truncation to 8bit color depth.
6809 Interpolate the gradients that should go where the bands are, and
6812 It is designed for playback only. Do not use it prior to
6813 lossy compression, because compression tends to lose the dither and
6814 bring back the bands.
6816 It accepts the following parameters:
6821 The maximum amount by which the filter will change any one pixel. This is also
6822 the threshold for detecting nearly flat regions. Acceptable values range from
6823 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
6827 The neighborhood to fit the gradient to. A larger radius makes for smoother
6828 gradients, but also prevents the filter from modifying the pixels near detailed
6829 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
6830 values will be clipped to the valid range.
6834 Alternatively, the options can be specified as a flat string:
6835 @var{strength}[:@var{radius}]
6837 @subsection Examples
6841 Apply the filter with a @code{3.5} strength and radius of @code{8}:
6847 Specify radius, omitting the strength (which will fall-back to the default
6858 Apply a Hald CLUT to a video stream.
6860 First input is the video stream to process, and second one is the Hald CLUT.
6861 The Hald CLUT input can be a simple picture or a complete video stream.
6863 The filter accepts the following options:
6867 Force termination when the shortest input terminates. Default is @code{0}.
6869 Continue applying the last CLUT after the end of the stream. A value of
6870 @code{0} disable the filter after the last frame of the CLUT is reached.
6871 Default is @code{1}.
6874 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
6875 filters share the same internals).
6877 More information about the Hald CLUT can be found on Eskil Steenberg's website
6878 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
6880 @subsection Workflow examples
6882 @subsubsection Hald CLUT video stream
6884 Generate an identity Hald CLUT stream altered with various effects:
6886 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
6889 Note: make sure you use a lossless codec.
6891 Then use it with @code{haldclut} to apply it on some random stream:
6893 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
6896 The Hald CLUT will be applied to the 10 first seconds (duration of
6897 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
6898 to the remaining frames of the @code{mandelbrot} stream.
6900 @subsubsection Hald CLUT with preview
6902 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
6903 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
6904 biggest possible square starting at the top left of the picture. The remaining
6905 padding pixels (bottom or right) will be ignored. This area can be used to add
6906 a preview of the Hald CLUT.
6908 Typically, the following generated Hald CLUT will be supported by the
6909 @code{haldclut} filter:
6912 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
6913 pad=iw+320 [padded_clut];
6914 smptebars=s=320x256, split [a][b];
6915 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
6916 [main][b] overlay=W-320" -frames:v 1 clut.png
6919 It contains the original and a preview of the effect of the CLUT: SMPTE color
6920 bars are displayed on the right-top, and below the same color bars processed by
6923 Then, the effect of this Hald CLUT can be visualized with:
6925 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
6930 Flip the input video horizontally.
6932 For example, to horizontally flip the input video with @command{ffmpeg}:
6934 ffmpeg -i in.avi -vf "hflip" out.avi
6938 This filter applies a global color histogram equalization on a
6941 It can be used to correct video that has a compressed range of pixel
6942 intensities. The filter redistributes the pixel intensities to
6943 equalize their distribution across the intensity range. It may be
6944 viewed as an "automatically adjusting contrast filter". This filter is
6945 useful only for correcting degraded or poorly captured source
6948 The filter accepts the following options:
6952 Determine the amount of equalization to be applied. As the strength
6953 is reduced, the distribution of pixel intensities more-and-more
6954 approaches that of the input frame. The value must be a float number
6955 in the range [0,1] and defaults to 0.200.
6958 Set the maximum intensity that can generated and scale the output
6959 values appropriately. The strength should be set as desired and then
6960 the intensity can be limited if needed to avoid washing-out. The value
6961 must be a float number in the range [0,1] and defaults to 0.210.
6964 Set the antibanding level. If enabled the filter will randomly vary
6965 the luminance of output pixels by a small amount to avoid banding of
6966 the histogram. Possible values are @code{none}, @code{weak} or
6967 @code{strong}. It defaults to @code{none}.
6972 Compute and draw a color distribution histogram for the input video.
6974 The computed histogram is a representation of the color component
6975 distribution in an image.
6977 The filter accepts the following options:
6983 It accepts the following values:
6986 Standard histogram that displays the color components distribution in an
6987 image. Displays color graph for each color component. Shows distribution of
6988 the Y, U, V, A or R, G, B components, depending on input format, in the
6989 current frame. Below each graph a color component scale meter is shown.
6992 Displays chroma values (U/V color placement) in a two dimensional
6993 graph (which is called a vectorscope). The brighter a pixel in the
6994 vectorscope, the more pixels of the input frame correspond to that pixel
6995 (i.e., more pixels have this chroma value). The V component is displayed on
6996 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
6997 side being V = 255. The U component is displayed on the vertical (Y) axis,
6998 with the top representing U = 0 and the bottom representing U = 255.
7000 The position of a white pixel in the graph corresponds to the chroma value of
7001 a pixel of the input clip. The graph can therefore be used to read the hue
7002 (color flavor) and the saturation (the dominance of the hue in the color). As
7003 the hue of a color changes, it moves around the square. At the center of the
7004 square the saturation is zero, which means that the corresponding pixel has no
7005 color. If the amount of a specific color is increased (while leaving the other
7006 colors unchanged) the saturation increases, and the indicator moves towards
7007 the edge of the square.
7010 Chroma values in vectorscope, similar as @code{color} but actual chroma values
7014 Per row/column color component graph. In row mode, the graph on the left side
7015 represents color component value 0 and the right side represents value = 255.
7016 In column mode, the top side represents color component value = 0 and bottom
7017 side represents value = 255.
7019 Default value is @code{levels}.
7022 Set height of level in @code{levels}. Default value is @code{200}.
7023 Allowed range is [50, 2048].
7026 Set height of color scale in @code{levels}. Default value is @code{12}.
7027 Allowed range is [0, 40].
7030 Set step for @code{waveform} mode. Smaller values are useful to find out how
7031 many values of the same luminance are distributed across input rows/columns.
7032 Default value is @code{10}. Allowed range is [1, 255].
7035 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
7036 Default is @code{row}.
7038 @item waveform_mirror
7039 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
7040 means mirrored. In mirrored mode, higher values will be represented on the left
7041 side for @code{row} mode and at the top for @code{column} mode. Default is
7042 @code{0} (unmirrored).
7045 Set display mode for @code{waveform} and @code{levels}.
7046 It accepts the following values:
7049 Display separate graph for the color components side by side in
7050 @code{row} waveform mode or one below the other in @code{column} waveform mode
7051 for @code{waveform} histogram mode. For @code{levels} histogram mode,
7052 per color component graphs are placed below each other.
7054 Using this display mode in @code{waveform} histogram mode makes it easy to
7055 spot color casts in the highlights and shadows of an image, by comparing the
7056 contours of the top and the bottom graphs of each waveform. Since whites,
7057 grays, and blacks are characterized by exactly equal amounts of red, green,
7058 and blue, neutral areas of the picture should display three waveforms of
7059 roughly equal width/height. If not, the correction is easy to perform by
7060 making level adjustments the three waveforms.
7063 Presents information identical to that in the @code{parade}, except
7064 that the graphs representing color components are superimposed directly
7067 This display mode in @code{waveform} histogram mode makes it easier to spot
7068 relative differences or similarities in overlapping areas of the color
7069 components that are supposed to be identical, such as neutral whites, grays,
7072 Default is @code{parade}.
7075 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
7076 Default is @code{linear}.
7079 Set what color components to display for mode @code{levels}.
7080 Default is @code{7}.
7083 @subsection Examples
7088 Calculate and draw histogram:
7090 ffplay -i input -vf histogram
7098 This is a high precision/quality 3d denoise filter. It aims to reduce
7099 image noise, producing smooth images and making still images really
7100 still. It should enhance compressibility.
7102 It accepts the following optional parameters:
7106 A non-negative floating point number which specifies spatial luma strength.
7109 @item chroma_spatial
7110 A non-negative floating point number which specifies spatial chroma strength.
7111 It defaults to 3.0*@var{luma_spatial}/4.0.
7114 A floating point number which specifies luma temporal strength. It defaults to
7115 6.0*@var{luma_spatial}/4.0.
7118 A floating point number which specifies chroma temporal strength. It defaults to
7119 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
7124 Apply a high-quality magnification filter designed for pixel art. This filter
7125 was originally created by Maxim Stepin.
7127 It accepts the following option:
7131 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
7132 @code{hq3x} and @code{4} for @code{hq4x}.
7133 Default is @code{3}.
7137 Stack input videos horizontally.
7139 All streams must be of same pixel format and of same height.
7141 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
7142 to create same output.
7144 The filter accept the following option:
7148 Set number of input streams. Default is 2.
7153 Modify the hue and/or the saturation of the input.
7155 It accepts the following parameters:
7159 Specify the hue angle as a number of degrees. It accepts an expression,
7160 and defaults to "0".
7163 Specify the saturation in the [-10,10] range. It accepts an expression and
7167 Specify the hue angle as a number of radians. It accepts an
7168 expression, and defaults to "0".
7171 Specify the brightness in the [-10,10] range. It accepts an expression and
7175 @option{h} and @option{H} are mutually exclusive, and can't be
7176 specified at the same time.
7178 The @option{b}, @option{h}, @option{H} and @option{s} option values are
7179 expressions containing the following constants:
7183 frame count of the input frame starting from 0
7186 presentation timestamp of the input frame expressed in time base units
7189 frame rate of the input video, NAN if the input frame rate is unknown
7192 timestamp expressed in seconds, NAN if the input timestamp is unknown
7195 time base of the input video
7198 @subsection Examples
7202 Set the hue to 90 degrees and the saturation to 1.0:
7208 Same command but expressing the hue in radians:
7214 Rotate hue and make the saturation swing between 0
7215 and 2 over a period of 1 second:
7217 hue="H=2*PI*t: s=sin(2*PI*t)+1"
7221 Apply a 3 seconds saturation fade-in effect starting at 0:
7226 The general fade-in expression can be written as:
7228 hue="s=min(0\, max((t-START)/DURATION\, 1))"
7232 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
7234 hue="s=max(0\, min(1\, (8-t)/3))"
7237 The general fade-out expression can be written as:
7239 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
7244 @subsection Commands
7246 This filter supports the following commands:
7252 Modify the hue and/or the saturation and/or brightness of the input video.
7253 The command accepts the same syntax of the corresponding option.
7255 If the specified expression is not valid, it is kept at its current
7261 Detect video interlacing type.
7263 This filter tries to detect if the input frames as interlaced, progressive,
7264 top or bottom field first. It will also try and detect fields that are
7265 repeated between adjacent frames (a sign of telecine).
7267 Single frame detection considers only immediately adjacent frames when classifying each frame.
7268 Multiple frame detection incorporates the classification history of previous frames.
7270 The filter will log these metadata values:
7273 @item single.current_frame
7274 Detected type of current frame using single-frame detection. One of:
7275 ``tff'' (top field first), ``bff'' (bottom field first),
7276 ``progressive'', or ``undetermined''
7279 Cumulative number of frames detected as top field first using single-frame detection.
7282 Cumulative number of frames detected as top field first using multiple-frame detection.
7285 Cumulative number of frames detected as bottom field first using single-frame detection.
7287 @item multiple.current_frame
7288 Detected type of current frame using multiple-frame detection. One of:
7289 ``tff'' (top field first), ``bff'' (bottom field first),
7290 ``progressive'', or ``undetermined''
7293 Cumulative number of frames detected as bottom field first using multiple-frame detection.
7295 @item single.progressive
7296 Cumulative number of frames detected as progressive using single-frame detection.
7298 @item multiple.progressive
7299 Cumulative number of frames detected as progressive using multiple-frame detection.
7301 @item single.undetermined
7302 Cumulative number of frames that could not be classified using single-frame detection.
7304 @item multiple.undetermined
7305 Cumulative number of frames that could not be classified using multiple-frame detection.
7307 @item repeated.current_frame
7308 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
7310 @item repeated.neither
7311 Cumulative number of frames with no repeated field.
7314 Cumulative number of frames with the top field repeated from the previous frame's top field.
7316 @item repeated.bottom
7317 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
7320 The filter accepts the following options:
7324 Set interlacing threshold.
7326 Set progressive threshold.
7328 Threshold for repeated field detection.
7330 Number of frames after which a given frame's contribution to the
7331 statistics is halved (i.e., it contributes only 0.5 to it's
7332 classification). The default of 0 means that all frames seen are given
7333 full weight of 1.0 forever.
7334 @item analyze_interlaced_flag
7335 When this is not 0 then idet will use the specified number of frames to determine
7336 if the interlaced flag is accurate, it will not count undetermined frames.
7337 If the flag is found to be accurate it will be used without any further
7338 computations, if it is found to be inaccurate it will be cleared without any
7339 further computations. This allows inserting the idet filter as a low computational
7340 method to clean up the interlaced flag
7345 Deinterleave or interleave fields.
7347 This filter allows one to process interlaced images fields without
7348 deinterlacing them. Deinterleaving splits the input frame into 2
7349 fields (so called half pictures). Odd lines are moved to the top
7350 half of the output image, even lines to the bottom half.
7351 You can process (filter) them independently and then re-interleave them.
7353 The filter accepts the following options:
7357 @item chroma_mode, c
7359 Available values for @var{luma_mode}, @var{chroma_mode} and
7360 @var{alpha_mode} are:
7366 @item deinterleave, d
7367 Deinterleave fields, placing one above the other.
7370 Interleave fields. Reverse the effect of deinterleaving.
7372 Default value is @code{none}.
7375 @item chroma_swap, cs
7376 @item alpha_swap, as
7377 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
7382 Apply inflate effect to the video.
7384 This filter replaces the pixel by the local(3x3) average by taking into account
7385 only values higher than the pixel.
7387 It accepts the following options:
7394 Limit the maximum change for each plane, default is 65535.
7395 If 0, plane will remain unchanged.
7400 Simple interlacing filter from progressive contents. This interleaves upper (or
7401 lower) lines from odd frames with lower (or upper) lines from even frames,
7402 halving the frame rate and preserving image height.
7405 Original Original New Frame
7406 Frame 'j' Frame 'j+1' (tff)
7407 ========== =========== ==================
7408 Line 0 --------------------> Frame 'j' Line 0
7409 Line 1 Line 1 ----> Frame 'j+1' Line 1
7410 Line 2 ---------------------> Frame 'j' Line 2
7411 Line 3 Line 3 ----> Frame 'j+1' Line 3
7413 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
7416 It accepts the following optional parameters:
7420 This determines whether the interlaced frame is taken from the even
7421 (tff - default) or odd (bff) lines of the progressive frame.
7424 Enable (default) or disable the vertical lowpass filter to avoid twitter
7425 interlacing and reduce moire patterns.
7430 Deinterlace input video by applying Donald Graft's adaptive kernel
7431 deinterling. Work on interlaced parts of a video to produce
7434 The description of the accepted parameters follows.
7438 Set the threshold which affects the filter's tolerance when
7439 determining if a pixel line must be processed. It must be an integer
7440 in the range [0,255] and defaults to 10. A value of 0 will result in
7441 applying the process on every pixels.
7444 Paint pixels exceeding the threshold value to white if set to 1.
7448 Set the fields order. Swap fields if set to 1, leave fields alone if
7452 Enable additional sharpening if set to 1. Default is 0.
7455 Enable twoway sharpening if set to 1. Default is 0.
7458 @subsection Examples
7462 Apply default values:
7464 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
7468 Enable additional sharpening:
7474 Paint processed pixels in white:
7480 @section lenscorrection
7482 Correct radial lens distortion
7484 This filter can be used to correct for radial distortion as can result from the use
7485 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
7486 one can use tools available for example as part of opencv or simply trial-and-error.
7487 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
7488 and extract the k1 and k2 coefficients from the resulting matrix.
7490 Note that effectively the same filter is available in the open-source tools Krita and
7491 Digikam from the KDE project.
7493 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
7494 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
7495 brightness distribution, so you may want to use both filters together in certain
7496 cases, though you will have to take care of ordering, i.e. whether vignetting should
7497 be applied before or after lens correction.
7501 The filter accepts the following options:
7505 Relative x-coordinate of the focal point of the image, and thereby the center of the
7506 distortion. This value has a range [0,1] and is expressed as fractions of the image
7509 Relative y-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 Coefficient of the quadratic correction term. 0.5 means no correction.
7515 Coefficient of the double quadratic correction term. 0.5 means no correction.
7518 The formula that generates the correction is:
7520 @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)
7522 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
7523 distances from the focal point in the source and target images, respectively.
7528 Apply a 3D LUT to an input video.
7530 The filter accepts the following options:
7534 Set the 3D LUT file name.
7536 Currently supported formats:
7548 Select interpolation mode.
7550 Available values are:
7554 Use values from the nearest defined point.
7556 Interpolate values using the 8 points defining a cube.
7558 Interpolate values using a tetrahedron.
7562 @section lut, lutrgb, lutyuv
7564 Compute a look-up table for binding each pixel component input value
7565 to an output value, and apply it to the input video.
7567 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
7568 to an RGB input video.
7570 These filters accept the following parameters:
7573 set first pixel component expression
7575 set second pixel component expression
7577 set third pixel component expression
7579 set fourth pixel component expression, corresponds to the alpha component
7582 set red component expression
7584 set green component expression
7586 set blue component expression
7588 alpha component expression
7591 set Y/luminance component expression
7593 set U/Cb component expression
7595 set V/Cr component expression
7598 Each of them specifies the expression to use for computing the lookup table for
7599 the corresponding pixel component values.
7601 The exact component associated to each of the @var{c*} options depends on the
7604 The @var{lut} filter requires either YUV or RGB pixel formats in input,
7605 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
7607 The expressions can contain the following constants and functions:
7612 The input width and height.
7615 The input value for the pixel component.
7618 The input value, clipped to the @var{minval}-@var{maxval} range.
7621 The maximum value for the pixel component.
7624 The minimum value for the pixel component.
7627 The negated value for the pixel component value, clipped to the
7628 @var{minval}-@var{maxval} range; it corresponds to the expression
7629 "maxval-clipval+minval".
7632 The computed value in @var{val}, clipped to the
7633 @var{minval}-@var{maxval} range.
7635 @item gammaval(gamma)
7636 The computed gamma correction value of the pixel component value,
7637 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
7639 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
7643 All expressions default to "val".
7645 @subsection Examples
7651 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
7652 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
7655 The above is the same as:
7657 lutrgb="r=negval:g=negval:b=negval"
7658 lutyuv="y=negval:u=negval:v=negval"
7668 Remove chroma components, turning the video into a graytone image:
7670 lutyuv="u=128:v=128"
7674 Apply a luma burning effect:
7680 Remove green and blue components:
7686 Set a constant alpha channel value on input:
7688 format=rgba,lutrgb=a="maxval-minval/2"
7692 Correct luminance gamma by a factor of 0.5:
7694 lutyuv=y=gammaval(0.5)
7698 Discard least significant bits of luma:
7700 lutyuv=y='bitand(val, 128+64+32)'
7704 @section maskedmerge
7706 Merge the first input stream with the second input stream using per pixel
7707 weights in the third input stream.
7709 A value of 0 in the third stream pixel component means that pixel component
7710 from first stream is returned unchanged, while maximum value (eg. 255 for
7711 8-bit videos) means that pixel component from second stream is returned
7712 unchanged. Intermediate values define the amount of merging between both
7713 input stream's pixel components.
7715 This filter accepts the following options:
7718 Set which planes will be processed as bitmap, unprocessed planes will be
7719 copied from first stream.
7720 By default value 0xf, all planes will be processed.
7725 Apply motion-compensation deinterlacing.
7727 It needs one field per frame as input and must thus be used together
7728 with yadif=1/3 or equivalent.
7730 This filter accepts the following options:
7733 Set the deinterlacing mode.
7735 It accepts one of the following values:
7740 use iterative motion estimation
7742 like @samp{slow}, but use multiple reference frames.
7744 Default value is @samp{fast}.
7747 Set the picture field parity assumed for the input video. It must be
7748 one of the following values:
7752 assume top field first
7754 assume bottom field first
7757 Default value is @samp{bff}.
7760 Set per-block quantization parameter (QP) used by the internal
7763 Higher values should result in a smoother motion vector field but less
7764 optimal individual vectors. Default value is 1.
7767 @section mergeplanes
7769 Merge color channel components from several video streams.
7771 The filter accepts up to 4 input streams, and merge selected input
7772 planes to the output video.
7774 This filter accepts the following options:
7777 Set input to output plane mapping. Default is @code{0}.
7779 The mappings is specified as a bitmap. It should be specified as a
7780 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
7781 mapping for the first plane of the output stream. 'A' sets the number of
7782 the input stream to use (from 0 to 3), and 'a' the plane number of the
7783 corresponding input to use (from 0 to 3). The rest of the mappings is
7784 similar, 'Bb' describes the mapping for the output stream second
7785 plane, 'Cc' describes the mapping for the output stream third plane and
7786 'Dd' describes the mapping for the output stream fourth plane.
7789 Set output pixel format. Default is @code{yuva444p}.
7792 @subsection Examples
7796 Merge three gray video streams of same width and height into single video stream:
7798 [a0][a1][a2]mergeplanes=0x001020:yuv444p
7802 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
7804 [a0][a1]mergeplanes=0x00010210:yuva444p
7808 Swap Y and A plane in yuva444p stream:
7810 format=yuva444p,mergeplanes=0x03010200:yuva444p
7814 Swap U and V plane in yuv420p stream:
7816 format=yuv420p,mergeplanes=0x000201:yuv420p
7820 Cast a rgb24 clip to yuv444p:
7822 format=rgb24,mergeplanes=0x000102:yuv444p
7828 Drop frames that do not differ greatly from the previous frame in
7829 order to reduce frame rate.
7831 The main use of this filter is for very-low-bitrate encoding
7832 (e.g. streaming over dialup modem), but it could in theory be used for
7833 fixing movies that were inverse-telecined incorrectly.
7835 A description of the accepted options follows.
7839 Set the maximum number of consecutive frames which can be dropped (if
7840 positive), or the minimum interval between dropped frames (if
7841 negative). If the value is 0, the frame is dropped unregarding the
7842 number of previous sequentially dropped frames.
7849 Set the dropping threshold values.
7851 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
7852 represent actual pixel value differences, so a threshold of 64
7853 corresponds to 1 unit of difference for each pixel, or the same spread
7854 out differently over the block.
7856 A frame is a candidate for dropping if no 8x8 blocks differ by more
7857 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
7858 meaning the whole image) differ by more than a threshold of @option{lo}.
7860 Default value for @option{hi} is 64*12, default value for @option{lo} is
7861 64*5, and default value for @option{frac} is 0.33.
7869 It accepts an integer in input; if non-zero it negates the
7870 alpha component (if available). The default value in input is 0.
7874 Force libavfilter not to use any of the specified pixel formats for the
7875 input to the next filter.
7877 It accepts the following parameters:
7881 A '|'-separated list of pixel format names, such as
7882 apix_fmts=yuv420p|monow|rgb24".
7886 @subsection Examples
7890 Force libavfilter to use a format different from @var{yuv420p} for the
7891 input to the vflip filter:
7893 noformat=pix_fmts=yuv420p,vflip
7897 Convert the input video to any of the formats not contained in the list:
7899 noformat=yuv420p|yuv444p|yuv410p
7905 Add noise on video input frame.
7907 The filter accepts the following options:
7915 Set noise seed for specific pixel component or all pixel components in case
7916 of @var{all_seed}. Default value is @code{123457}.
7918 @item all_strength, alls
7919 @item c0_strength, c0s
7920 @item c1_strength, c1s
7921 @item c2_strength, c2s
7922 @item c3_strength, c3s
7923 Set noise strength for specific pixel component or all pixel components in case
7924 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
7926 @item all_flags, allf
7931 Set pixel component flags or set flags for all components if @var{all_flags}.
7932 Available values for component flags are:
7935 averaged temporal noise (smoother)
7937 mix random noise with a (semi)regular pattern
7939 temporal noise (noise pattern changes between frames)
7941 uniform noise (gaussian otherwise)
7945 @subsection Examples
7947 Add temporal and uniform noise to input video:
7949 noise=alls=20:allf=t+u
7954 Pass the video source unchanged to the output.
7957 Optical Character Recognition
7959 This filter uses Tesseract for optical character recognition.
7961 It accepts the following options:
7965 Set datapath to tesseract data. Default is to use whatever was
7966 set at installation.
7969 Set language, default is "eng".
7972 Set character whitelist.
7975 Set character blacklist.
7978 The filter exports recognized text as the frame metadata @code{lavfi.ocr.text}.
7982 Apply a video transform using libopencv.
7984 To enable this filter, install the libopencv library and headers and
7985 configure FFmpeg with @code{--enable-libopencv}.
7987 It accepts the following parameters:
7992 The name of the libopencv filter to apply.
7995 The parameters to pass to the libopencv filter. If not specified, the default
8000 Refer to the official libopencv documentation for more precise
8002 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
8004 Several libopencv filters are supported; see the following subsections.
8009 Dilate an image by using a specific structuring element.
8010 It corresponds to the libopencv function @code{cvDilate}.
8012 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
8014 @var{struct_el} represents a structuring element, and has the syntax:
8015 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
8017 @var{cols} and @var{rows} represent the number of columns and rows of
8018 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
8019 point, and @var{shape} the shape for the structuring element. @var{shape}
8020 must be "rect", "cross", "ellipse", or "custom".
8022 If the value for @var{shape} is "custom", it must be followed by a
8023 string of the form "=@var{filename}". The file with name
8024 @var{filename} is assumed to represent a binary image, with each
8025 printable character corresponding to a bright pixel. When a custom
8026 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
8027 or columns and rows of the read file are assumed instead.
8029 The default value for @var{struct_el} is "3x3+0x0/rect".
8031 @var{nb_iterations} specifies the number of times the transform is
8032 applied to the image, and defaults to 1.
8036 # Use the default values
8039 # Dilate using a structuring element with a 5x5 cross, iterating two times
8040 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
8042 # Read the shape from the file diamond.shape, iterating two times.
8043 # The file diamond.shape may contain a pattern of characters like this
8049 # The specified columns and rows are ignored
8050 # but the anchor point coordinates are not
8051 ocv=dilate:0x0+2x2/custom=diamond.shape|2
8056 Erode an image by using a specific structuring element.
8057 It corresponds to the libopencv function @code{cvErode}.
8059 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
8060 with the same syntax and semantics as the @ref{dilate} filter.
8064 Smooth the input video.
8066 The filter takes the following parameters:
8067 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
8069 @var{type} is the type of smooth filter to apply, and must be one of
8070 the following values: "blur", "blur_no_scale", "median", "gaussian",
8071 or "bilateral". The default value is "gaussian".
8073 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
8074 depend on the smooth type. @var{param1} and
8075 @var{param2} accept integer positive values or 0. @var{param3} and
8076 @var{param4} accept floating point values.
8078 The default value for @var{param1} is 3. The default value for the
8079 other parameters is 0.
8081 These parameters correspond to the parameters assigned to the
8082 libopencv function @code{cvSmooth}.
8087 Overlay one video on top of another.
8089 It takes two inputs and has one output. The first input is the "main"
8090 video on which the second input is overlaid.
8092 It accepts the following parameters:
8094 A description of the accepted options follows.
8099 Set the expression for the x and y coordinates of the overlaid video
8100 on the main video. Default value is "0" for both expressions. In case
8101 the expression is invalid, it is set to a huge value (meaning that the
8102 overlay will not be displayed within the output visible area).
8105 The action to take when EOF is encountered on the secondary input; it accepts
8106 one of the following values:
8110 Repeat the last frame (the default).
8114 Pass the main input through.
8118 Set when the expressions for @option{x}, and @option{y} are evaluated.
8120 It accepts the following values:
8123 only evaluate expressions once during the filter initialization or
8124 when a command is processed
8127 evaluate expressions for each incoming frame
8130 Default value is @samp{frame}.
8133 If set to 1, force the output to terminate when the shortest input
8134 terminates. Default value is 0.
8137 Set the format for the output video.
8139 It accepts the following values:
8154 Default value is @samp{yuv420}.
8156 @item rgb @emph{(deprecated)}
8157 If set to 1, force the filter to accept inputs in the RGB
8158 color space. Default value is 0. This option is deprecated, use
8159 @option{format} instead.
8162 If set to 1, force the filter to draw the last overlay frame over the
8163 main input until the end of the stream. A value of 0 disables this
8164 behavior. Default value is 1.
8167 The @option{x}, and @option{y} expressions can contain the following
8173 The main input width and height.
8177 The overlay input width and height.
8181 The computed values for @var{x} and @var{y}. They are evaluated for
8186 horizontal and vertical chroma subsample values of the output
8187 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
8191 the number of input frame, starting from 0
8194 the position in the file of the input frame, NAN if unknown
8197 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
8201 Note that the @var{n}, @var{pos}, @var{t} variables are available only
8202 when evaluation is done @emph{per frame}, and will evaluate to NAN
8203 when @option{eval} is set to @samp{init}.
8205 Be aware that frames are taken from each input video in timestamp
8206 order, hence, if their initial timestamps differ, it is a good idea
8207 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
8208 have them begin in the same zero timestamp, as the example for
8209 the @var{movie} filter does.
8211 You can chain together more overlays but you should test the
8212 efficiency of such approach.
8214 @subsection Commands
8216 This filter supports the following commands:
8220 Modify the x and y of the overlay input.
8221 The command accepts the same syntax of the corresponding option.
8223 If the specified expression is not valid, it is kept at its current
8227 @subsection Examples
8231 Draw the overlay at 10 pixels from the bottom right corner of the main
8234 overlay=main_w-overlay_w-10:main_h-overlay_h-10
8237 Using named options the example above becomes:
8239 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
8243 Insert a transparent PNG logo in the bottom left corner of the input,
8244 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
8246 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
8250 Insert 2 different transparent PNG logos (second logo on bottom
8251 right corner) using the @command{ffmpeg} tool:
8253 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
8257 Add a transparent color layer on top of the main video; @code{WxH}
8258 must specify the size of the main input to the overlay filter:
8260 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
8264 Play an original video and a filtered version (here with the deshake
8265 filter) side by side using the @command{ffplay} tool:
8267 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
8270 The above command is the same as:
8272 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
8276 Make a sliding overlay appearing from the left to the right top part of the
8277 screen starting since time 2:
8279 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
8283 Compose output by putting two input videos side to side:
8285 ffmpeg -i left.avi -i right.avi -filter_complex "
8286 nullsrc=size=200x100 [background];
8287 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
8288 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
8289 [background][left] overlay=shortest=1 [background+left];
8290 [background+left][right] overlay=shortest=1:x=100 [left+right]
8295 Mask 10-20 seconds of a video by applying the delogo filter to a section
8297 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
8298 -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]'
8303 Chain several overlays in cascade:
8305 nullsrc=s=200x200 [bg];
8306 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
8307 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
8308 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
8309 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
8310 [in3] null, [mid2] overlay=100:100 [out0]
8317 Apply Overcomplete Wavelet denoiser.
8319 The filter accepts the following options:
8325 Larger depth values will denoise lower frequency components more, but
8326 slow down filtering.
8328 Must be an int in the range 8-16, default is @code{8}.
8330 @item luma_strength, ls
8333 Must be a double value in the range 0-1000, default is @code{1.0}.
8335 @item chroma_strength, cs
8336 Set chroma strength.
8338 Must be a double value in the range 0-1000, default is @code{1.0}.
8344 Add paddings to the input image, and place the original input at the
8345 provided @var{x}, @var{y} coordinates.
8347 It accepts the following parameters:
8352 Specify an expression for the size of the output image with the
8353 paddings added. If the value for @var{width} or @var{height} is 0, the
8354 corresponding input size is used for the output.
8356 The @var{width} expression can reference the value set by the
8357 @var{height} expression, and vice versa.
8359 The default value of @var{width} and @var{height} is 0.
8363 Specify the offsets to place the input image at within the padded area,
8364 with respect to the top/left border of the output image.
8366 The @var{x} expression can reference the value set by the @var{y}
8367 expression, and vice versa.
8369 The default value of @var{x} and @var{y} is 0.
8372 Specify the color of the padded area. For the syntax of this option,
8373 check the "Color" section in the ffmpeg-utils manual.
8375 The default value of @var{color} is "black".
8378 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
8379 options are expressions containing the following constants:
8384 The input video width and height.
8388 These are the same as @var{in_w} and @var{in_h}.
8392 The output width and height (the size of the padded area), as
8393 specified by the @var{width} and @var{height} expressions.
8397 These are the same as @var{out_w} and @var{out_h}.
8401 The x and y offsets as specified by the @var{x} and @var{y}
8402 expressions, or NAN if not yet specified.
8405 same as @var{iw} / @var{ih}
8408 input sample aspect ratio
8411 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
8415 The horizontal and vertical chroma subsample values. For example for the
8416 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8419 @subsection Examples
8423 Add paddings with the color "violet" to the input video. The output video
8424 size is 640x480, and the top-left corner of the input video is placed at
8427 pad=640:480:0:40:violet
8430 The example above is equivalent to the following command:
8432 pad=width=640:height=480:x=0:y=40:color=violet
8436 Pad the input to get an output with dimensions increased by 3/2,
8437 and put the input video at the center of the padded area:
8439 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
8443 Pad the input to get a squared output with size equal to the maximum
8444 value between the input width and height, and put the input video at
8445 the center of the padded area:
8447 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
8451 Pad the input to get a final w/h ratio of 16:9:
8453 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
8457 In case of anamorphic video, in order to set the output display aspect
8458 correctly, it is necessary to use @var{sar} in the expression,
8459 according to the relation:
8461 (ih * X / ih) * sar = output_dar
8462 X = output_dar / sar
8465 Thus the previous example needs to be modified to:
8467 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
8471 Double the output size and put the input video in the bottom-right
8472 corner of the output padded area:
8474 pad="2*iw:2*ih:ow-iw:oh-ih"
8481 Generate one palette for a whole video stream.
8483 It accepts the following options:
8487 Set the maximum number of colors to quantize in the palette.
8488 Note: the palette will still contain 256 colors; the unused palette entries
8491 @item reserve_transparent
8492 Create a palette of 255 colors maximum and reserve the last one for
8493 transparency. Reserving the transparency color is useful for GIF optimization.
8494 If not set, the maximum of colors in the palette will be 256. You probably want
8495 to disable this option for a standalone image.
8499 Set statistics mode.
8501 It accepts the following values:
8504 Compute full frame histograms.
8506 Compute histograms only for the part that differs from previous frame. This
8507 might be relevant to give more importance to the moving part of your input if
8508 the background is static.
8511 Default value is @var{full}.
8514 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
8515 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
8516 color quantization of the palette. This information is also visible at
8517 @var{info} logging level.
8519 @subsection Examples
8523 Generate a representative palette of a given video using @command{ffmpeg}:
8525 ffmpeg -i input.mkv -vf palettegen palette.png
8531 Use a palette to downsample an input video stream.
8533 The filter takes two inputs: one video stream and a palette. The palette must
8534 be a 256 pixels image.
8536 It accepts the following options:
8540 Select dithering mode. Available algorithms are:
8543 Ordered 8x8 bayer dithering (deterministic)
8545 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
8546 Note: this dithering is sometimes considered "wrong" and is included as a
8548 @item floyd_steinberg
8549 Floyd and Steingberg dithering (error diffusion)
8551 Frankie Sierra dithering v2 (error diffusion)
8553 Frankie Sierra dithering v2 "Lite" (error diffusion)
8556 Default is @var{sierra2_4a}.
8559 When @var{bayer} dithering is selected, this option defines the scale of the
8560 pattern (how much the crosshatch pattern is visible). A low value means more
8561 visible pattern for less banding, and higher value means less visible pattern
8562 at the cost of more banding.
8564 The option must be an integer value in the range [0,5]. Default is @var{2}.
8567 If set, define the zone to process
8571 Only the changing rectangle will be reprocessed. This is similar to GIF
8572 cropping/offsetting compression mechanism. This option can be useful for speed
8573 if only a part of the image is changing, and has use cases such as limiting the
8574 scope of the error diffusal @option{dither} to the rectangle that bounds the
8575 moving scene (it leads to more deterministic output if the scene doesn't change
8576 much, and as a result less moving noise and better GIF compression).
8579 Default is @var{none}.
8582 @subsection Examples
8586 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
8587 using @command{ffmpeg}:
8589 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
8593 @section perspective
8595 Correct perspective of video not recorded perpendicular to the screen.
8597 A description of the accepted parameters follows.
8608 Set coordinates expression for top left, top right, bottom left and bottom right corners.
8609 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
8610 If the @code{sense} option is set to @code{source}, then the specified points will be sent
8611 to the corners of the destination. If the @code{sense} option is set to @code{destination},
8612 then the corners of the source will be sent to the specified coordinates.
8614 The expressions can use the following variables:
8619 the width and height of video frame.
8623 Set interpolation for perspective correction.
8625 It accepts the following values:
8631 Default value is @samp{linear}.
8634 Set interpretation of coordinate options.
8636 It accepts the following values:
8640 Send point in the source specified by the given coordinates to
8641 the corners of the destination.
8643 @item 1, destination
8645 Send the corners of the source to the point in the destination specified
8646 by the given coordinates.
8648 Default value is @samp{source}.
8654 Delay interlaced video by one field time so that the field order changes.
8656 The intended use is to fix PAL movies that have been captured with the
8657 opposite field order to the film-to-video transfer.
8659 A description of the accepted parameters follows.
8665 It accepts the following values:
8668 Capture field order top-first, transfer bottom-first.
8669 Filter will delay the bottom field.
8672 Capture field order bottom-first, transfer top-first.
8673 Filter will delay the top field.
8676 Capture and transfer with the same field order. This mode only exists
8677 for the documentation of the other options to refer to, but if you
8678 actually select it, the filter will faithfully do nothing.
8681 Capture field order determined automatically by field flags, transfer
8683 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
8684 basis using field flags. If no field information is available,
8685 then this works just like @samp{u}.
8688 Capture unknown or varying, transfer opposite.
8689 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
8690 analyzing the images and selecting the alternative that produces best
8691 match between the fields.
8694 Capture top-first, transfer unknown or varying.
8695 Filter selects among @samp{t} and @samp{p} using image analysis.
8698 Capture bottom-first, transfer unknown or varying.
8699 Filter selects among @samp{b} and @samp{p} using image analysis.
8702 Capture determined by field flags, transfer unknown or varying.
8703 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
8704 image analysis. If no field information is available, then this works just
8705 like @samp{U}. This is the default mode.
8708 Both capture and transfer unknown or varying.
8709 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
8713 @section pixdesctest
8715 Pixel format descriptor test filter, mainly useful for internal
8716 testing. The output video should be equal to the input video.
8720 format=monow, pixdesctest
8723 can be used to test the monowhite pixel format descriptor definition.
8727 Enable the specified chain of postprocessing subfilters using libpostproc. This
8728 library should be automatically selected with a GPL build (@code{--enable-gpl}).
8729 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
8730 Each subfilter and some options have a short and a long name that can be used
8731 interchangeably, i.e. dr/dering are the same.
8733 The filters accept the following options:
8737 Set postprocessing subfilters string.
8740 All subfilters share common options to determine their scope:
8744 Honor the quality commands for this subfilter.
8747 Do chrominance filtering, too (default).
8750 Do luminance filtering only (no chrominance).
8753 Do chrominance filtering only (no luminance).
8756 These options can be appended after the subfilter name, separated by a '|'.
8758 Available subfilters are:
8761 @item hb/hdeblock[|difference[|flatness]]
8762 Horizontal deblocking filter
8765 Difference factor where higher values mean more deblocking (default: @code{32}).
8767 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8770 @item vb/vdeblock[|difference[|flatness]]
8771 Vertical deblocking filter
8774 Difference factor where higher values mean more deblocking (default: @code{32}).
8776 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8779 @item ha/hadeblock[|difference[|flatness]]
8780 Accurate horizontal deblocking filter
8783 Difference factor where higher values mean more deblocking (default: @code{32}).
8785 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8788 @item va/vadeblock[|difference[|flatness]]
8789 Accurate vertical deblocking filter
8792 Difference factor where higher values mean more deblocking (default: @code{32}).
8794 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8798 The horizontal and vertical deblocking filters share the difference and
8799 flatness values so you cannot set different horizontal and vertical
8804 Experimental horizontal deblocking filter
8807 Experimental vertical deblocking filter
8812 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
8815 larger -> stronger filtering
8817 larger -> stronger filtering
8819 larger -> stronger filtering
8822 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
8825 Stretch luminance to @code{0-255}.
8828 @item lb/linblenddeint
8829 Linear blend deinterlacing filter that deinterlaces the given block by
8830 filtering all lines with a @code{(1 2 1)} filter.
8832 @item li/linipoldeint
8833 Linear interpolating deinterlacing filter that deinterlaces the given block by
8834 linearly interpolating every second line.
8836 @item ci/cubicipoldeint
8837 Cubic interpolating deinterlacing filter deinterlaces the given block by
8838 cubically interpolating every second line.
8840 @item md/mediandeint
8841 Median deinterlacing filter that deinterlaces the given block by applying a
8842 median filter to every second line.
8844 @item fd/ffmpegdeint
8845 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
8846 second line with a @code{(-1 4 2 4 -1)} filter.
8849 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
8850 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
8852 @item fq/forceQuant[|quantizer]
8853 Overrides the quantizer table from the input with the constant quantizer you
8861 Default pp filter combination (@code{hb|a,vb|a,dr|a})
8864 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
8867 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
8870 @subsection Examples
8874 Apply horizontal and vertical deblocking, deringing and automatic
8875 brightness/contrast:
8881 Apply default filters without brightness/contrast correction:
8887 Apply default filters and temporal denoiser:
8889 pp=default/tmpnoise|1|2|3
8893 Apply deblocking on luminance only, and switch vertical deblocking on or off
8894 automatically depending on available CPU time:
8901 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
8902 similar to spp = 6 with 7 point DCT, where only the center sample is
8905 The filter accepts the following options:
8909 Force a constant quantization parameter. It accepts an integer in range
8910 0 to 63. If not set, the filter will use the QP from the video stream
8914 Set thresholding mode. Available modes are:
8918 Set hard thresholding.
8920 Set soft thresholding (better de-ringing effect, but likely blurrier).
8922 Set medium thresholding (good results, default).
8928 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
8929 Ratio) between two input videos.
8931 This filter takes in input two input videos, the first input is
8932 considered the "main" source and is passed unchanged to the
8933 output. The second input is used as a "reference" video for computing
8936 Both video inputs must have the same resolution and pixel format for
8937 this filter to work correctly. Also it assumes that both inputs
8938 have the same number of frames, which are compared one by one.
8940 The obtained average PSNR is printed through the logging system.
8942 The filter stores the accumulated MSE (mean squared error) of each
8943 frame, and at the end of the processing it is averaged across all frames
8944 equally, and the following formula is applied to obtain the PSNR:
8947 PSNR = 10*log10(MAX^2/MSE)
8950 Where MAX is the average of the maximum values of each component of the
8953 The description of the accepted parameters follows.
8957 If specified the filter will use the named file to save the PSNR of
8958 each individual frame. When filename equals "-" the data is sent to
8962 The file printed if @var{stats_file} is selected, contains a sequence of
8963 key/value pairs of the form @var{key}:@var{value} for each compared
8966 A description of each shown parameter follows:
8970 sequential number of the input frame, starting from 1
8973 Mean Square Error pixel-by-pixel average difference of the compared
8974 frames, averaged over all the image components.
8976 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
8977 Mean Square Error pixel-by-pixel average difference of the compared
8978 frames for the component specified by the suffix.
8980 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
8981 Peak Signal to Noise ratio of the compared frames for the component
8982 specified by the suffix.
8987 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
8988 [main][ref] psnr="stats_file=stats.log" [out]
8991 On this example the input file being processed is compared with the
8992 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
8993 is stored in @file{stats.log}.
8998 Pulldown reversal (inverse telecine) filter, capable of handling mixed
8999 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
9002 The pullup filter is designed to take advantage of future context in making
9003 its decisions. This filter is stateless in the sense that it does not lock
9004 onto a pattern to follow, but it instead looks forward to the following
9005 fields in order to identify matches and rebuild progressive frames.
9007 To produce content with an even framerate, insert the fps filter after
9008 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
9009 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
9011 The filter accepts the following options:
9018 These options set the amount of "junk" to ignore at the left, right, top, and
9019 bottom of the image, respectively. Left and right are in units of 8 pixels,
9020 while top and bottom are in units of 2 lines.
9021 The default is 8 pixels on each side.
9024 Set the strict breaks. Setting this option to 1 will reduce the chances of
9025 filter generating an occasional mismatched frame, but it may also cause an
9026 excessive number of frames to be dropped during high motion sequences.
9027 Conversely, setting it to -1 will make filter match fields more easily.
9028 This may help processing of video where there is slight blurring between
9029 the fields, but may also cause there to be interlaced frames in the output.
9030 Default value is @code{0}.
9033 Set the metric plane to use. It accepts the following values:
9039 Use chroma blue plane.
9042 Use chroma red plane.
9045 This option may be set to use chroma plane instead of the default luma plane
9046 for doing filter's computations. This may improve accuracy on very clean
9047 source material, but more likely will decrease accuracy, especially if there
9048 is chroma noise (rainbow effect) or any grayscale video.
9049 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
9050 load and make pullup usable in realtime on slow machines.
9053 For best results (without duplicated frames in the output file) it is
9054 necessary to change the output frame rate. For example, to inverse
9055 telecine NTSC input:
9057 ffmpeg -i input -vf pullup -r 24000/1001 ...
9062 Change video quantization parameters (QP).
9064 The filter accepts the following option:
9068 Set expression for quantization parameter.
9071 The expression is evaluated through the eval API and can contain, among others,
9072 the following constants:
9076 1 if index is not 129, 0 otherwise.
9079 Sequentional index starting from -129 to 128.
9082 @subsection Examples
9094 Flush video frames from internal cache of frames into a random order.
9095 No frame is discarded.
9096 Inspired by @ref{frei0r} nervous filter.
9100 Set size in number of frames of internal cache, in range from @code{2} to
9101 @code{512}. Default is @code{30}.
9104 Set seed for random number generator, must be an integer included between
9105 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9106 less than @code{0}, the filter will try to use a good random seed on a
9110 @section removegrain
9112 The removegrain filter is a spatial denoiser for progressive video.
9116 Set mode for the first plane.
9119 Set mode for the second plane.
9122 Set mode for the third plane.
9125 Set mode for the fourth plane.
9128 Range of mode is from 0 to 24. Description of each mode follows:
9132 Leave input plane unchanged. Default.
9135 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
9138 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
9141 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
9144 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
9145 This is equivalent to a median filter.
9148 Line-sensitive clipping giving the minimal change.
9151 Line-sensitive clipping, intermediate.
9154 Line-sensitive clipping, intermediate.
9157 Line-sensitive clipping, intermediate.
9160 Line-sensitive clipping on a line where the neighbours pixels are the closest.
9163 Replaces the target pixel with the closest neighbour.
9166 [1 2 1] horizontal and vertical kernel blur.
9172 Bob mode, interpolates top field from the line where the neighbours
9173 pixels are the closest.
9176 Bob mode, interpolates bottom field from the line where the neighbours
9177 pixels are the closest.
9180 Bob mode, interpolates top field. Same as 13 but with a more complicated
9181 interpolation formula.
9184 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
9185 interpolation formula.
9188 Clips the pixel with the minimum and maximum of respectively the maximum and
9189 minimum of each pair of opposite neighbour pixels.
9192 Line-sensitive clipping using opposite neighbours whose greatest distance from
9193 the current pixel is minimal.
9196 Replaces the pixel with the average of its 8 neighbours.
9199 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
9202 Clips pixels using the averages of opposite neighbour.
9205 Same as mode 21 but simpler and faster.
9208 Small edge and halo removal, but reputed useless.
9216 Suppress a TV station logo, using an image file to determine which
9217 pixels comprise the logo. It works by filling in the pixels that
9218 comprise the logo with neighboring pixels.
9220 The filter accepts the following options:
9224 Set the filter bitmap file, which can be any image format supported by
9225 libavformat. The width and height of the image file must match those of the
9226 video stream being processed.
9229 Pixels in the provided bitmap image with a value of zero are not
9230 considered part of the logo, non-zero pixels are considered part of
9231 the logo. If you use white (255) for the logo and black (0) for the
9232 rest, you will be safe. For making the filter bitmap, it is
9233 recommended to take a screen capture of a black frame with the logo
9234 visible, and then using a threshold filter followed by the erode
9235 filter once or twice.
9237 If needed, little splotches can be fixed manually. Remember that if
9238 logo pixels are not covered, the filter quality will be much
9239 reduced. Marking too many pixels as part of the logo does not hurt as
9240 much, but it will increase the amount of blurring needed to cover over
9241 the image and will destroy more information than necessary, and extra
9242 pixels will slow things down on a large logo.
9244 @section repeatfields
9246 This filter uses the repeat_field flag from the Video ES headers and hard repeats
9247 fields based on its value.
9249 @section reverse, areverse
9253 Warning: This filter requires memory to buffer the entire clip, so trimming
9256 @subsection Examples
9260 Take the first 5 seconds of a clip, and reverse it.
9268 Rotate video by an arbitrary angle expressed in radians.
9270 The filter accepts the following options:
9272 A description of the optional parameters follows.
9275 Set an expression for the angle by which to rotate the input video
9276 clockwise, expressed as a number of radians. A negative value will
9277 result in a counter-clockwise rotation. By default it is set to "0".
9279 This expression is evaluated for each frame.
9282 Set the output width expression, default value is "iw".
9283 This expression is evaluated just once during configuration.
9286 Set the output height expression, default value is "ih".
9287 This expression is evaluated just once during configuration.
9290 Enable bilinear interpolation if set to 1, a value of 0 disables
9291 it. Default value is 1.
9294 Set the color used to fill the output area not covered by the rotated
9295 image. For the general syntax of this option, check the "Color" section in the
9296 ffmpeg-utils manual. If the special value "none" is selected then no
9297 background is printed (useful for example if the background is never shown).
9299 Default value is "black".
9302 The expressions for the angle and the output size can contain the
9303 following constants and functions:
9307 sequential number of the input frame, starting from 0. It is always NAN
9308 before the first frame is filtered.
9311 time in seconds of the input frame, it is set to 0 when the filter is
9312 configured. It is always NAN before the first frame is filtered.
9316 horizontal and vertical chroma subsample values. For example for the
9317 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9321 the input video width and height
9325 the output width and height, that is the size of the padded area as
9326 specified by the @var{width} and @var{height} expressions
9330 the minimal width/height required for completely containing the input
9331 video rotated by @var{a} radians.
9333 These are only available when computing the @option{out_w} and
9334 @option{out_h} expressions.
9337 @subsection Examples
9341 Rotate the input by PI/6 radians clockwise:
9347 Rotate the input by PI/6 radians counter-clockwise:
9353 Rotate the input by 45 degrees clockwise:
9359 Apply a constant rotation with period T, starting from an angle of PI/3:
9361 rotate=PI/3+2*PI*t/T
9365 Make the input video rotation oscillating with a period of T
9366 seconds and an amplitude of A radians:
9368 rotate=A*sin(2*PI/T*t)
9372 Rotate the video, output size is chosen so that the whole rotating
9373 input video is always completely contained in the output:
9375 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
9379 Rotate the video, reduce the output size so that no background is ever
9382 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
9386 @subsection Commands
9388 The filter supports the following commands:
9392 Set the angle expression.
9393 The command accepts the same syntax of the corresponding option.
9395 If the specified expression is not valid, it is kept at its current
9401 Apply Shape Adaptive Blur.
9403 The filter accepts the following options:
9406 @item luma_radius, lr
9407 Set luma blur filter strength, must be a value in range 0.1-4.0, default
9408 value is 1.0. A greater value will result in a more blurred image, and
9409 in slower processing.
9411 @item luma_pre_filter_radius, lpfr
9412 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
9415 @item luma_strength, ls
9416 Set luma maximum difference between pixels to still be considered, must
9417 be a value in the 0.1-100.0 range, default value is 1.0.
9419 @item chroma_radius, cr
9420 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
9421 greater value will result in a more blurred image, and in slower
9424 @item chroma_pre_filter_radius, cpfr
9425 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
9427 @item chroma_strength, cs
9428 Set chroma maximum difference between pixels to still be considered,
9429 must be a value in the 0.1-100.0 range.
9432 Each chroma option value, if not explicitly specified, is set to the
9433 corresponding luma option value.
9438 Scale (resize) the input video, using the libswscale library.
9440 The scale filter forces the output display aspect ratio to be the same
9441 of the input, by changing the output sample aspect ratio.
9443 If the input image format is different from the format requested by
9444 the next filter, the scale filter will convert the input to the
9448 The filter accepts the following options, or any of the options
9449 supported by the libswscale scaler.
9451 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
9452 the complete list of scaler options.
9457 Set the output video dimension expression. Default value is the input
9460 If the value is 0, the input width is used for the output.
9462 If one of the values is -1, the scale filter will use a value that
9463 maintains the aspect ratio of the input image, calculated from the
9464 other specified dimension. If both of them are -1, the input size is
9467 If one of the values is -n with n > 1, the scale filter will also use a value
9468 that maintains the aspect ratio of the input image, calculated from the other
9469 specified dimension. After that it will, however, make sure that the calculated
9470 dimension is divisible by n and adjust the value if necessary.
9472 See below for the list of accepted constants for use in the dimension
9476 Set the interlacing mode. It accepts the following values:
9480 Force interlaced aware scaling.
9483 Do not apply interlaced scaling.
9486 Select interlaced aware scaling depending on whether the source frames
9487 are flagged as interlaced or not.
9490 Default value is @samp{0}.
9493 Set libswscale scaling flags. See
9494 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
9495 complete list of values. If not explicitly specified the filter applies
9499 Set the video size. For the syntax of this option, check the
9500 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9502 @item in_color_matrix
9503 @item out_color_matrix
9504 Set in/output YCbCr color space type.
9506 This allows the autodetected value to be overridden as well as allows forcing
9507 a specific value used for the output and encoder.
9509 If not specified, the color space type depends on the pixel format.
9515 Choose automatically.
9518 Format conforming to International Telecommunication Union (ITU)
9519 Recommendation BT.709.
9522 Set color space conforming to the United States Federal Communications
9523 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
9526 Set color space conforming to:
9530 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
9533 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
9536 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
9541 Set color space conforming to SMPTE ST 240:1999.
9546 Set in/output YCbCr sample range.
9548 This allows the autodetected value to be overridden as well as allows forcing
9549 a specific value used for the output and encoder. If not specified, the
9550 range depends on the pixel format. Possible values:
9554 Choose automatically.
9557 Set full range (0-255 in case of 8-bit luma).
9560 Set "MPEG" range (16-235 in case of 8-bit luma).
9563 @item force_original_aspect_ratio
9564 Enable decreasing or increasing output video width or height if necessary to
9565 keep the original aspect ratio. Possible values:
9569 Scale the video as specified and disable this feature.
9572 The output video dimensions will automatically be decreased if needed.
9575 The output video dimensions will automatically be increased if needed.
9579 One useful instance of this option is that when you know a specific device's
9580 maximum allowed resolution, you can use this to limit the output video to
9581 that, while retaining the aspect ratio. For example, device A allows
9582 1280x720 playback, and your video is 1920x800. Using this option (set it to
9583 decrease) and specifying 1280x720 to the command line makes the output
9586 Please note that this is a different thing than specifying -1 for @option{w}
9587 or @option{h}, you still need to specify the output resolution for this option
9592 The values of the @option{w} and @option{h} options are expressions
9593 containing the following constants:
9598 The input width and height
9602 These are the same as @var{in_w} and @var{in_h}.
9606 The output (scaled) width and height
9610 These are the same as @var{out_w} and @var{out_h}
9613 The same as @var{iw} / @var{ih}
9616 input sample aspect ratio
9619 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
9623 horizontal and vertical input chroma subsample values. For example for the
9624 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9628 horizontal and vertical output chroma subsample values. For example for the
9629 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9632 @subsection Examples
9636 Scale the input video to a size of 200x100
9641 This is equivalent to:
9652 Specify a size abbreviation for the output size:
9657 which can also be written as:
9663 Scale the input to 2x:
9669 The above is the same as:
9675 Scale the input to 2x with forced interlaced scaling:
9677 scale=2*iw:2*ih:interl=1
9681 Scale the input to half size:
9687 Increase the width, and set the height to the same size:
9700 Increase the height, and set the width to 3/2 of the height:
9702 scale=w=3/2*oh:h=3/5*ih
9706 Increase the size, making the size a multiple of the chroma
9709 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
9713 Increase the width to a maximum of 500 pixels,
9714 keeping the same aspect ratio as the input:
9716 scale=w='min(500\, iw*3/2):h=-1'
9720 @subsection Commands
9722 This filter supports the following commands:
9726 Set the output video dimension expression.
9727 The command accepts the same syntax of the corresponding option.
9729 If the specified expression is not valid, it is kept at its current
9735 Scale (resize) the input video, based on a reference video.
9737 See the scale filter for available options, scale2ref supports the same but
9738 uses the reference video instead of the main input as basis.
9740 @subsection Examples
9744 Scale a subtitle stream to match the main video in size before overlaying
9746 'scale2ref[b][a];[a][b]overlay'
9750 @section separatefields
9752 The @code{separatefields} takes a frame-based video input and splits
9753 each frame into its components fields, producing a new half height clip
9754 with twice the frame rate and twice the frame count.
9756 This filter use field-dominance information in frame to decide which
9757 of each pair of fields to place first in the output.
9758 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
9760 @section setdar, setsar
9762 The @code{setdar} filter sets the Display Aspect Ratio for the filter
9765 This is done by changing the specified Sample (aka Pixel) Aspect
9766 Ratio, according to the following equation:
9768 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
9771 Keep in mind that the @code{setdar} filter does not modify the pixel
9772 dimensions of the video frame. Also, the display aspect ratio set by
9773 this filter may be changed by later filters in the filterchain,
9774 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
9777 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
9778 the filter output video.
9780 Note that as a consequence of the application of this filter, the
9781 output display aspect ratio will change according to the equation
9784 Keep in mind that the sample aspect ratio set by the @code{setsar}
9785 filter may be changed by later filters in the filterchain, e.g. if
9786 another "setsar" or a "setdar" filter is applied.
9788 It accepts the following parameters:
9791 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
9792 Set the aspect ratio used by the filter.
9794 The parameter can be a floating point number string, an expression, or
9795 a string of the form @var{num}:@var{den}, where @var{num} and
9796 @var{den} are the numerator and denominator of the aspect ratio. If
9797 the parameter is not specified, it is assumed the value "0".
9798 In case the form "@var{num}:@var{den}" is used, the @code{:} character
9802 Set the maximum integer value to use for expressing numerator and
9803 denominator when reducing the expressed aspect ratio to a rational.
9804 Default value is @code{100}.
9808 The parameter @var{sar} is an expression containing
9809 the following constants:
9813 These are approximated values for the mathematical constants e
9814 (Euler's number), pi (Greek pi), and phi (the golden ratio).
9817 The input width and height.
9820 These are the same as @var{w} / @var{h}.
9823 The input sample aspect ratio.
9826 The input display aspect ratio. It is the same as
9827 (@var{w} / @var{h}) * @var{sar}.
9830 Horizontal and vertical chroma subsample values. For example, for the
9831 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9834 @subsection Examples
9839 To change the display aspect ratio to 16:9, specify one of the following:
9847 To change the sample aspect ratio to 10:11, specify:
9853 To set a display aspect ratio of 16:9, and specify a maximum integer value of
9854 1000 in the aspect ratio reduction, use the command:
9856 setdar=ratio=16/9:max=1000
9864 Force field for the output video frame.
9866 The @code{setfield} filter marks the interlace type field for the
9867 output frames. It does not change the input frame, but only sets the
9868 corresponding property, which affects how the frame is treated by
9869 following filters (e.g. @code{fieldorder} or @code{yadif}).
9871 The filter accepts the following options:
9876 Available values are:
9880 Keep the same field property.
9883 Mark the frame as bottom-field-first.
9886 Mark the frame as top-field-first.
9889 Mark the frame as progressive.
9895 Show a line containing various information for each input video frame.
9896 The input video is not modified.
9898 The shown line contains a sequence of key/value pairs of the form
9899 @var{key}:@var{value}.
9901 The following values are shown in the output:
9905 The (sequential) number of the input frame, starting from 0.
9908 The Presentation TimeStamp of the input frame, expressed as a number of
9909 time base units. The time base unit depends on the filter input pad.
9912 The Presentation TimeStamp of the input frame, expressed as a number of
9916 The position of the frame in the input stream, or -1 if this information is
9917 unavailable and/or meaningless (for example in case of synthetic video).
9920 The pixel format name.
9923 The sample aspect ratio of the input frame, expressed in the form
9924 @var{num}/@var{den}.
9927 The size of the input frame. For the syntax of this option, check the
9928 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9931 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
9932 for bottom field first).
9935 This is 1 if the frame is a key frame, 0 otherwise.
9938 The picture type of the input frame ("I" for an I-frame, "P" for a
9939 P-frame, "B" for a B-frame, or "?" for an unknown type).
9940 Also refer to the documentation of the @code{AVPictureType} enum and of
9941 the @code{av_get_picture_type_char} function defined in
9942 @file{libavutil/avutil.h}.
9945 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
9947 @item plane_checksum
9948 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
9949 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
9952 @section showpalette
9954 Displays the 256 colors palette of each frame. This filter is only relevant for
9955 @var{pal8} pixel format frames.
9957 It accepts the following option:
9961 Set the size of the box used to represent one palette color entry. Default is
9962 @code{30} (for a @code{30x30} pixel box).
9965 @section shuffleframes
9967 Reorder and/or duplicate video frames.
9969 It accepts the following parameters:
9973 Set the destination indexes of input frames.
9974 This is space or '|' separated list of indexes that maps input frames to output
9975 frames. Number of indexes also sets maximal value that each index may have.
9978 The first frame has the index 0. The default is to keep the input unchanged.
9980 Swap second and third frame of every three frames of the input:
9982 ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
9985 @section shuffleplanes
9987 Reorder and/or duplicate video planes.
9989 It accepts the following parameters:
9994 The index of the input plane to be used as the first output plane.
9997 The index of the input plane to be used as the second output plane.
10000 The index of the input plane to be used as the third output plane.
10003 The index of the input plane to be used as the fourth output plane.
10007 The first plane has the index 0. The default is to keep the input unchanged.
10009 Swap the second and third planes of the input:
10011 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
10014 @anchor{signalstats}
10015 @section signalstats
10016 Evaluate various visual metrics that assist in determining issues associated
10017 with the digitization of analog video media.
10019 By default the filter will log these metadata values:
10023 Display the minimal Y value contained within the input frame. Expressed in
10027 Display the Y value at the 10% percentile within the input frame. Expressed in
10031 Display the average Y value within the input frame. Expressed in range of
10035 Display the Y value at the 90% percentile within the input frame. Expressed in
10039 Display the maximum Y value contained within the input frame. Expressed in
10043 Display the minimal U value contained within the input frame. Expressed in
10047 Display the U value at the 10% percentile within the input frame. Expressed in
10051 Display the average U value within the input frame. Expressed in range of
10055 Display the U value at the 90% percentile within the input frame. Expressed in
10059 Display the maximum U value contained within the input frame. Expressed in
10063 Display the minimal V value contained within the input frame. Expressed in
10067 Display the V value at the 10% percentile within the input frame. Expressed in
10071 Display the average V value within the input frame. Expressed in range of
10075 Display the V value at the 90% percentile within the input frame. Expressed in
10079 Display the maximum V value contained within the input frame. Expressed in
10083 Display the minimal saturation value contained within the input frame.
10084 Expressed in range of [0-~181.02].
10087 Display the saturation value at the 10% percentile within the input frame.
10088 Expressed in range of [0-~181.02].
10091 Display the average saturation value within the input frame. Expressed in range
10095 Display the saturation value at the 90% percentile within the input frame.
10096 Expressed in range of [0-~181.02].
10099 Display the maximum saturation value contained within the input frame.
10100 Expressed in range of [0-~181.02].
10103 Display the median value for hue within the input frame. Expressed in range of
10107 Display the average value for hue within the input frame. Expressed in range of
10111 Display the average of sample value difference between all values of the Y
10112 plane in the current frame and corresponding values of the previous input frame.
10113 Expressed in range of [0-255].
10116 Display the average of sample value difference between all values of the U
10117 plane in the current frame and corresponding values of the previous input frame.
10118 Expressed in range of [0-255].
10121 Display the average of sample value difference between all values of the V
10122 plane in the current frame and corresponding values of the previous input frame.
10123 Expressed in range of [0-255].
10126 The filter accepts the following options:
10132 @option{stat} specify an additional form of image analysis.
10133 @option{out} output video with the specified type of pixel highlighted.
10135 Both options accept the following values:
10139 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
10140 unlike the neighboring pixels of the same field. Examples of temporal outliers
10141 include the results of video dropouts, head clogs, or tape tracking issues.
10144 Identify @var{vertical line repetition}. Vertical line repetition includes
10145 similar rows of pixels within a frame. In born-digital video vertical line
10146 repetition is common, but this pattern is uncommon in video digitized from an
10147 analog source. When it occurs in video that results from the digitization of an
10148 analog source it can indicate concealment from a dropout compensator.
10151 Identify pixels that fall outside of legal broadcast range.
10155 Set the highlight color for the @option{out} option. The default color is
10159 @subsection Examples
10163 Output data of various video metrics:
10165 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
10169 Output specific data about the minimum and maximum values of the Y plane per frame:
10171 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
10175 Playback video while highlighting pixels that are outside of broadcast range in red.
10177 ffplay example.mov -vf signalstats="out=brng:color=red"
10181 Playback video with signalstats metadata drawn over the frame.
10183 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
10186 The contents of signalstat_drawtext.txt used in the command are:
10189 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
10190 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
10191 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
10192 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
10200 Blur the input video without impacting the outlines.
10202 It accepts the following options:
10205 @item luma_radius, lr
10206 Set the luma radius. The option value must be a float number in
10207 the range [0.1,5.0] that specifies the variance of the gaussian filter
10208 used to blur the image (slower if larger). Default value is 1.0.
10210 @item luma_strength, ls
10211 Set the luma strength. The option value must be a float number
10212 in the range [-1.0,1.0] that configures the blurring. A value included
10213 in [0.0,1.0] will blur the image whereas a value included in
10214 [-1.0,0.0] will sharpen the image. Default value is 1.0.
10216 @item luma_threshold, lt
10217 Set the luma threshold used as a coefficient to determine
10218 whether a pixel should be blurred or not. The option value must be an
10219 integer in the range [-30,30]. A value of 0 will filter all the image,
10220 a value included in [0,30] will filter flat areas and a value included
10221 in [-30,0] will filter edges. Default value is 0.
10223 @item chroma_radius, cr
10224 Set the chroma radius. The option value must be a float number in
10225 the range [0.1,5.0] that specifies the variance of the gaussian filter
10226 used to blur the image (slower if larger). Default value is 1.0.
10228 @item chroma_strength, cs
10229 Set the chroma strength. The option value must be a float number
10230 in the range [-1.0,1.0] that configures the blurring. A value included
10231 in [0.0,1.0] will blur the image whereas a value included in
10232 [-1.0,0.0] will sharpen the image. Default value is 1.0.
10234 @item chroma_threshold, ct
10235 Set the chroma threshold used as a coefficient to determine
10236 whether a pixel should be blurred or not. The option value must be an
10237 integer in the range [-30,30]. A value of 0 will filter all the image,
10238 a value included in [0,30] will filter flat areas and a value included
10239 in [-30,0] will filter edges. Default value is 0.
10242 If a chroma option is not explicitly set, the corresponding luma value
10247 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
10249 This filter takes in input two input videos, the first input is
10250 considered the "main" source and is passed unchanged to the
10251 output. The second input is used as a "reference" video for computing
10254 Both video inputs must have the same resolution and pixel format for
10255 this filter to work correctly. Also it assumes that both inputs
10256 have the same number of frames, which are compared one by one.
10258 The filter stores the calculated SSIM of each frame.
10260 The description of the accepted parameters follows.
10263 @item stats_file, f
10264 If specified the filter will use the named file to save the SSIM of
10265 each individual frame. When filename equals "-" the data is sent to
10269 The file printed if @var{stats_file} is selected, contains a sequence of
10270 key/value pairs of the form @var{key}:@var{value} for each compared
10273 A description of each shown parameter follows:
10277 sequential number of the input frame, starting from 1
10279 @item Y, U, V, R, G, B
10280 SSIM of the compared frames for the component specified by the suffix.
10283 SSIM of the compared frames for the whole frame.
10286 Same as above but in dB representation.
10291 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
10292 [main][ref] ssim="stats_file=stats.log" [out]
10295 On this example the input file being processed is compared with the
10296 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
10297 is stored in @file{stats.log}.
10299 Another example with both psnr and ssim at same time:
10301 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
10306 Convert between different stereoscopic image formats.
10308 The filters accept the following options:
10312 Set stereoscopic image format of input.
10314 Available values for input image formats are:
10317 side by side parallel (left eye left, right eye right)
10320 side by side crosseye (right eye left, left eye right)
10323 side by side parallel with half width resolution
10324 (left eye left, right eye right)
10327 side by side crosseye with half width resolution
10328 (right eye left, left eye right)
10331 above-below (left eye above, right eye below)
10334 above-below (right eye above, left eye below)
10337 above-below with half height resolution
10338 (left eye above, right eye below)
10341 above-below with half height resolution
10342 (right eye above, left eye below)
10345 alternating frames (left eye first, right eye second)
10348 alternating frames (right eye first, left eye second)
10351 interleaved rows (left eye has top row, right eye starts on next row)
10354 interleaved rows (right eye has top row, left eye starts on next row)
10356 Default value is @samp{sbsl}.
10360 Set stereoscopic image format of output.
10362 Available values for output image formats are all the input formats as well as:
10365 anaglyph red/blue gray
10366 (red filter on left eye, blue filter on right eye)
10369 anaglyph red/green gray
10370 (red filter on left eye, green filter on right eye)
10373 anaglyph red/cyan gray
10374 (red filter on left eye, cyan filter on right eye)
10377 anaglyph red/cyan half colored
10378 (red filter on left eye, cyan filter on right eye)
10381 anaglyph red/cyan color
10382 (red filter on left eye, cyan filter on right eye)
10385 anaglyph red/cyan color optimized with the least squares projection of dubois
10386 (red filter on left eye, cyan filter on right eye)
10389 anaglyph green/magenta gray
10390 (green filter on left eye, magenta filter on right eye)
10393 anaglyph green/magenta half colored
10394 (green filter on left eye, magenta filter on right eye)
10397 anaglyph green/magenta colored
10398 (green filter on left eye, magenta filter on right eye)
10401 anaglyph green/magenta color optimized with the least squares projection of dubois
10402 (green filter on left eye, magenta filter on right eye)
10405 anaglyph yellow/blue gray
10406 (yellow filter on left eye, blue filter on right eye)
10409 anaglyph yellow/blue half colored
10410 (yellow filter on left eye, blue filter on right eye)
10413 anaglyph yellow/blue colored
10414 (yellow filter on left eye, blue filter on right eye)
10417 anaglyph yellow/blue color optimized with the least squares projection of dubois
10418 (yellow filter on left eye, blue filter on right eye)
10421 mono output (left eye only)
10424 mono output (right eye only)
10427 checkerboard, left eye first
10430 checkerboard, right eye first
10433 interleaved columns, left eye first
10436 interleaved columns, right eye first
10439 Default value is @samp{arcd}.
10442 @subsection Examples
10446 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
10452 Convert input video from above below (left eye above, right eye below) to side by side crosseye.
10461 Apply a simple postprocessing filter that compresses and decompresses the image
10462 at several (or - in the case of @option{quality} level @code{6} - all) shifts
10463 and average the results.
10465 The filter accepts the following options:
10469 Set quality. This option defines the number of levels for averaging. It accepts
10470 an integer in the range 0-6. If set to @code{0}, the filter will have no
10471 effect. A value of @code{6} means the higher quality. For each increment of
10472 that value the speed drops by a factor of approximately 2. Default value is
10476 Force a constant quantization parameter. If not set, the filter will use the QP
10477 from the video stream (if available).
10480 Set thresholding mode. Available modes are:
10484 Set hard thresholding (default).
10486 Set soft thresholding (better de-ringing effect, but likely blurrier).
10489 @item use_bframe_qp
10490 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
10491 option may cause flicker since the B-Frames have often larger QP. Default is
10492 @code{0} (not enabled).
10498 Draw subtitles on top of input video using the libass library.
10500 To enable compilation of this filter you need to configure FFmpeg with
10501 @code{--enable-libass}. This filter also requires a build with libavcodec and
10502 libavformat to convert the passed subtitles file to ASS (Advanced Substation
10503 Alpha) subtitles format.
10505 The filter accepts the following options:
10509 Set the filename of the subtitle file to read. It must be specified.
10511 @item original_size
10512 Specify the size of the original video, the video for which the ASS file
10513 was composed. For the syntax of this option, check the
10514 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10515 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
10516 correctly scale the fonts if the aspect ratio has been changed.
10519 Set a directory path containing fonts that can be used by the filter.
10520 These fonts will be used in addition to whatever the font provider uses.
10523 Set subtitles input character encoding. @code{subtitles} filter only. Only
10524 useful if not UTF-8.
10526 @item stream_index, si
10527 Set subtitles stream index. @code{subtitles} filter only.
10530 Override default style or script info parameters of the subtitles. It accepts a
10531 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
10534 If the first key is not specified, it is assumed that the first value
10535 specifies the @option{filename}.
10537 For example, to render the file @file{sub.srt} on top of the input
10538 video, use the command:
10543 which is equivalent to:
10545 subtitles=filename=sub.srt
10548 To render the default subtitles stream from file @file{video.mkv}, use:
10550 subtitles=video.mkv
10553 To render the second subtitles stream from that file, use:
10555 subtitles=video.mkv:si=1
10558 To make the subtitles stream from @file{sub.srt} appear in transparent green
10559 @code{DejaVu Serif}, use:
10561 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
10564 @section super2xsai
10566 Scale the input by 2x and smooth using the Super2xSaI (Scale and
10567 Interpolate) pixel art scaling algorithm.
10569 Useful for enlarging pixel art images without reducing sharpness.
10576 Apply telecine process to the video.
10578 This filter accepts the following options:
10587 The default value is @code{top}.
10591 A string of numbers representing the pulldown pattern you wish to apply.
10592 The default value is @code{23}.
10596 Some typical patterns:
10601 24p: 2332 (preferred)
10608 24p: 222222222223 ("Euro pulldown")
10614 Select the most representative frame in a given sequence of consecutive frames.
10616 The filter accepts the following options:
10620 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
10621 will pick one of them, and then handle the next batch of @var{n} frames until
10622 the end. Default is @code{100}.
10625 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
10626 value will result in a higher memory usage, so a high value is not recommended.
10628 @subsection Examples
10632 Extract one picture each 50 frames:
10638 Complete example of a thumbnail creation with @command{ffmpeg}:
10640 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
10646 Tile several successive frames together.
10648 The filter accepts the following options:
10653 Set the grid size (i.e. the number of lines and columns). For the syntax of
10654 this option, check the
10655 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10658 Set the maximum number of frames to render in the given area. It must be less
10659 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
10660 the area will be used.
10663 Set the outer border margin in pixels.
10666 Set the inner border thickness (i.e. the number of pixels between frames). For
10667 more advanced padding options (such as having different values for the edges),
10668 refer to the pad video filter.
10671 Specify the color of the unused area. For the syntax of this option, check the
10672 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
10676 @subsection Examples
10680 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
10682 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
10684 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
10685 duplicating each output frame to accommodate the originally detected frame
10689 Display @code{5} pictures in an area of @code{3x2} frames,
10690 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
10691 mixed flat and named options:
10693 tile=3x2:nb_frames=5:padding=7:margin=2
10697 @section tinterlace
10699 Perform various types of temporal field interlacing.
10701 Frames are counted starting from 1, so the first input frame is
10704 The filter accepts the following options:
10709 Specify the mode of the interlacing. This option can also be specified
10710 as a value alone. See below for a list of values for this option.
10712 Available values are:
10716 Move odd frames into the upper field, even into the lower field,
10717 generating a double height frame at half frame rate.
10721 Frame 1 Frame 2 Frame 3 Frame 4
10723 11111 22222 33333 44444
10724 11111 22222 33333 44444
10725 11111 22222 33333 44444
10726 11111 22222 33333 44444
10740 Only output even frames, odd frames are dropped, generating a frame with
10741 unchanged height at half frame rate.
10746 Frame 1 Frame 2 Frame 3 Frame 4
10748 11111 22222 33333 44444
10749 11111 22222 33333 44444
10750 11111 22222 33333 44444
10751 11111 22222 33333 44444
10761 Only output odd frames, even frames are dropped, generating a frame with
10762 unchanged height at half frame rate.
10767 Frame 1 Frame 2 Frame 3 Frame 4
10769 11111 22222 33333 44444
10770 11111 22222 33333 44444
10771 11111 22222 33333 44444
10772 11111 22222 33333 44444
10782 Expand each frame to full height, but pad alternate lines with black,
10783 generating a frame with double height at the same input frame rate.
10788 Frame 1 Frame 2 Frame 3 Frame 4
10790 11111 22222 33333 44444
10791 11111 22222 33333 44444
10792 11111 22222 33333 44444
10793 11111 22222 33333 44444
10796 11111 ..... 33333 .....
10797 ..... 22222 ..... 44444
10798 11111 ..... 33333 .....
10799 ..... 22222 ..... 44444
10800 11111 ..... 33333 .....
10801 ..... 22222 ..... 44444
10802 11111 ..... 33333 .....
10803 ..... 22222 ..... 44444
10807 @item interleave_top, 4
10808 Interleave the upper field from odd frames with the lower field from
10809 even frames, generating a frame with unchanged height at half frame rate.
10814 Frame 1 Frame 2 Frame 3 Frame 4
10816 11111<- 22222 33333<- 44444
10817 11111 22222<- 33333 44444<-
10818 11111<- 22222 33333<- 44444
10819 11111 22222<- 33333 44444<-
10829 @item interleave_bottom, 5
10830 Interleave the lower field from odd frames with the upper field from
10831 even frames, generating a frame with unchanged height at half frame rate.
10836 Frame 1 Frame 2 Frame 3 Frame 4
10838 11111 22222<- 33333 44444<-
10839 11111<- 22222 33333<- 44444
10840 11111 22222<- 33333 44444<-
10841 11111<- 22222 33333<- 44444
10851 @item interlacex2, 6
10852 Double frame rate with unchanged height. Frames are inserted each
10853 containing the second temporal field from the previous input frame and
10854 the first temporal field from the next input frame. This mode relies on
10855 the top_field_first flag. Useful for interlaced video displays with no
10856 field synchronisation.
10861 Frame 1 Frame 2 Frame 3 Frame 4
10863 11111 22222 33333 44444
10864 11111 22222 33333 44444
10865 11111 22222 33333 44444
10866 11111 22222 33333 44444
10869 11111 22222 22222 33333 33333 44444 44444
10870 11111 11111 22222 22222 33333 33333 44444
10871 11111 22222 22222 33333 33333 44444 44444
10872 11111 11111 22222 22222 33333 33333 44444
10876 Move odd frames into the upper field, even into the lower field,
10877 generating a double height frame at same frame rate.
10881 Frame 1 Frame 2 Frame 3 Frame 4
10883 11111 22222 33333 44444
10884 11111 22222 33333 44444
10885 11111 22222 33333 44444
10886 11111 22222 33333 44444
10889 11111 33333 33333 55555
10890 22222 22222 44444 44444
10891 11111 33333 33333 55555
10892 22222 22222 44444 44444
10893 11111 33333 33333 55555
10894 22222 22222 44444 44444
10895 11111 33333 33333 55555
10896 22222 22222 44444 44444
10901 Numeric values are deprecated but are accepted for backward
10902 compatibility reasons.
10904 Default mode is @code{merge}.
10907 Specify flags influencing the filter process.
10909 Available value for @var{flags} is:
10912 @item low_pass_filter, vlfp
10913 Enable vertical low-pass filtering in the filter.
10914 Vertical low-pass filtering is required when creating an interlaced
10915 destination from a progressive source which contains high-frequency
10916 vertical detail. Filtering will reduce interlace 'twitter' and Moire
10919 Vertical low-pass filtering can only be enabled for @option{mode}
10920 @var{interleave_top} and @var{interleave_bottom}.
10927 Transpose rows with columns in the input video and optionally flip it.
10929 It accepts the following parameters:
10934 Specify the transposition direction.
10936 Can assume the following values:
10938 @item 0, 4, cclock_flip
10939 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
10947 Rotate by 90 degrees clockwise, that is:
10955 Rotate by 90 degrees counterclockwise, that is:
10962 @item 3, 7, clock_flip
10963 Rotate by 90 degrees clockwise and vertically flip, that is:
10971 For values between 4-7, the transposition is only done if the input
10972 video geometry is portrait and not landscape. These values are
10973 deprecated, the @code{passthrough} option should be used instead.
10975 Numerical values are deprecated, and should be dropped in favor of
10976 symbolic constants.
10979 Do not apply the transposition if the input geometry matches the one
10980 specified by the specified value. It accepts the following values:
10983 Always apply transposition.
10985 Preserve portrait geometry (when @var{height} >= @var{width}).
10987 Preserve landscape geometry (when @var{width} >= @var{height}).
10990 Default value is @code{none}.
10993 For example to rotate by 90 degrees clockwise and preserve portrait
10996 transpose=dir=1:passthrough=portrait
10999 The command above can also be specified as:
11001 transpose=1:portrait
11005 Trim the input so that the output contains one continuous subpart of the input.
11007 It accepts the following parameters:
11010 Specify the time of the start of the kept section, i.e. the frame with the
11011 timestamp @var{start} will be the first frame in the output.
11014 Specify the time of the first frame that will be dropped, i.e. the frame
11015 immediately preceding the one with the timestamp @var{end} will be the last
11016 frame in the output.
11019 This is the same as @var{start}, except this option sets the start timestamp
11020 in timebase units instead of seconds.
11023 This is the same as @var{end}, except this option sets the end timestamp
11024 in timebase units instead of seconds.
11027 The maximum duration of the output in seconds.
11030 The number of the first frame that should be passed to the output.
11033 The number of the first frame that should be dropped.
11036 @option{start}, @option{end}, and @option{duration} are expressed as time
11037 duration specifications; see
11038 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
11039 for the accepted syntax.
11041 Note that the first two sets of the start/end options and the @option{duration}
11042 option look at the frame timestamp, while the _frame variants simply count the
11043 frames that pass through the filter. Also note that this filter does not modify
11044 the timestamps. If you wish for the output timestamps to start at zero, insert a
11045 setpts filter after the trim filter.
11047 If multiple start or end options are set, this filter tries to be greedy and
11048 keep all the frames that match at least one of the specified constraints. To keep
11049 only the part that matches all the constraints at once, chain multiple trim
11052 The defaults are such that all the input is kept. So it is possible to set e.g.
11053 just the end values to keep everything before the specified time.
11058 Drop everything except the second minute of input:
11060 ffmpeg -i INPUT -vf trim=60:120
11064 Keep only the first second:
11066 ffmpeg -i INPUT -vf trim=duration=1
11075 Sharpen or blur the input video.
11077 It accepts the following parameters:
11080 @item luma_msize_x, lx
11081 Set the luma matrix horizontal size. It must be an odd integer between
11082 3 and 63. The default value is 5.
11084 @item luma_msize_y, ly
11085 Set the luma matrix vertical size. It must be an odd integer between 3
11086 and 63. The default value is 5.
11088 @item luma_amount, la
11089 Set the luma effect strength. It must be a floating point number, reasonable
11090 values lay between -1.5 and 1.5.
11092 Negative values will blur the input video, while positive values will
11093 sharpen it, a value of zero will disable the effect.
11095 Default value is 1.0.
11097 @item chroma_msize_x, cx
11098 Set the chroma matrix horizontal size. It must be an odd integer
11099 between 3 and 63. The default value is 5.
11101 @item chroma_msize_y, cy
11102 Set the chroma matrix vertical size. It must be an odd integer
11103 between 3 and 63. The default value is 5.
11105 @item chroma_amount, ca
11106 Set the chroma effect strength. It must be a floating point number, reasonable
11107 values lay between -1.5 and 1.5.
11109 Negative values will blur the input video, while positive values will
11110 sharpen it, a value of zero will disable the effect.
11112 Default value is 0.0.
11115 If set to 1, specify using OpenCL capabilities, only available if
11116 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
11120 All parameters are optional and default to the equivalent of the
11121 string '5:5:1.0:5:5:0.0'.
11123 @subsection Examples
11127 Apply strong luma sharpen effect:
11129 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
11133 Apply a strong blur of both luma and chroma parameters:
11135 unsharp=7:7:-2:7:7:-2
11141 Apply ultra slow/simple postprocessing filter that compresses and decompresses
11142 the image at several (or - in the case of @option{quality} level @code{8} - all)
11143 shifts and average the results.
11145 The way this differs from the behavior of spp is that uspp actually encodes &
11146 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
11147 DCT similar to MJPEG.
11149 The filter accepts the following options:
11153 Set quality. This option defines the number of levels for averaging. It accepts
11154 an integer in the range 0-8. If set to @code{0}, the filter will have no
11155 effect. A value of @code{8} means the higher quality. For each increment of
11156 that value the speed drops by a factor of approximately 2. Default value is
11160 Force a constant quantization parameter. If not set, the filter will use the QP
11161 from the video stream (if available).
11164 @section vectorscope
11166 Display 2 color component values in the two dimensional graph (which is called
11169 This filter accepts the following options:
11173 Set vectorscope mode.
11175 It accepts the following values:
11178 Gray values are displayed on graph, higher brightness means more pixels have
11179 same component color value on location in graph. This is the default mode.
11182 Gray values are displayed on graph. Surrounding pixels values which are not
11183 present in video frame are drawn in gradient of 2 color components which are
11184 set by option @code{x} and @code{y}.
11187 Actual color components values present in video frame are displayed on graph.
11190 Similar as color2 but higher frequency of same values @code{x} and @code{y}
11191 on graph increases value of another color component, which is luminance by
11192 default values of @code{x} and @code{y}.
11195 Actual colors present in video frame are displayed on graph. If two different
11196 colors map to same position on graph then color with higher value of component
11197 not present in graph is picked.
11201 Set which color component will be represented on X-axis. Default is @code{1}.
11204 Set which color component will be represented on Y-axis. Default is @code{2}.
11207 Set intensity, used by modes: gray, color and color3 for increasing brightness
11208 of color component which represents frequency of (X, Y) location in graph.
11213 No envelope, this is default.
11216 Instant envelope, even darkest single pixel will be clearly highlighted.
11219 Hold maximum and minimum values presented in graph over time. This way you
11220 can still spot out of range values without constantly looking at vectorscope.
11223 Peak and instant envelope combined together.
11227 @anchor{vidstabdetect}
11228 @section vidstabdetect
11230 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
11231 @ref{vidstabtransform} for pass 2.
11233 This filter generates a file with relative translation and rotation
11234 transform information about subsequent frames, which is then used by
11235 the @ref{vidstabtransform} filter.
11237 To enable compilation of this filter you need to configure FFmpeg with
11238 @code{--enable-libvidstab}.
11240 This filter accepts the following options:
11244 Set the path to the file used to write the transforms information.
11245 Default value is @file{transforms.trf}.
11248 Set how shaky the video is and how quick the camera is. It accepts an
11249 integer in the range 1-10, a value of 1 means little shakiness, a
11250 value of 10 means strong shakiness. Default value is 5.
11253 Set the accuracy of the detection process. It must be a value in the
11254 range 1-15. A value of 1 means low accuracy, a value of 15 means high
11255 accuracy. Default value is 15.
11258 Set stepsize of the search process. The region around minimum is
11259 scanned with 1 pixel resolution. Default value is 6.
11262 Set minimum contrast. Below this value a local measurement field is
11263 discarded. Must be a floating point value in the range 0-1. Default
11267 Set reference frame number for tripod mode.
11269 If enabled, the motion of the frames is compared to a reference frame
11270 in the filtered stream, identified by the specified number. The idea
11271 is to compensate all movements in a more-or-less static scene and keep
11272 the camera view absolutely still.
11274 If set to 0, it is disabled. The frames are counted starting from 1.
11277 Show fields and transforms in the resulting frames. It accepts an
11278 integer in the range 0-2. Default value is 0, which disables any
11282 @subsection Examples
11286 Use default values:
11292 Analyze strongly shaky movie and put the results in file
11293 @file{mytransforms.trf}:
11295 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
11299 Visualize the result of internal transformations in the resulting
11302 vidstabdetect=show=1
11306 Analyze a video with medium shakiness using @command{ffmpeg}:
11308 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
11312 @anchor{vidstabtransform}
11313 @section vidstabtransform
11315 Video stabilization/deshaking: pass 2 of 2,
11316 see @ref{vidstabdetect} for pass 1.
11318 Read a file with transform information for each frame and
11319 apply/compensate them. Together with the @ref{vidstabdetect}
11320 filter this can be used to deshake videos. See also
11321 @url{http://public.hronopik.de/vid.stab}. It is important to also use
11322 the @ref{unsharp} filter, see below.
11324 To enable compilation of this filter you need to configure FFmpeg with
11325 @code{--enable-libvidstab}.
11327 @subsection Options
11331 Set path to the file used to read the transforms. Default value is
11332 @file{transforms.trf}.
11335 Set the number of frames (value*2 + 1) used for lowpass filtering the
11336 camera movements. Default value is 10.
11338 For example a number of 10 means that 21 frames are used (10 in the
11339 past and 10 in the future) to smoothen the motion in the video. A
11340 larger value leads to a smoother video, but limits the acceleration of
11341 the camera (pan/tilt movements). 0 is a special case where a static
11342 camera is simulated.
11345 Set the camera path optimization algorithm.
11347 Accepted values are:
11350 gaussian kernel low-pass filter on camera motion (default)
11352 averaging on transformations
11356 Set maximal number of pixels to translate frames. Default value is -1,
11360 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
11361 value is -1, meaning no limit.
11364 Specify how to deal with borders that may be visible due to movement
11367 Available values are:
11370 keep image information from previous frame (default)
11372 fill the border black
11376 Invert transforms if set to 1. Default value is 0.
11379 Consider transforms as relative to previous frame if set to 1,
11380 absolute if set to 0. Default value is 0.
11383 Set percentage to zoom. A positive value will result in a zoom-in
11384 effect, a negative value in a zoom-out effect. Default value is 0 (no
11388 Set optimal zooming to avoid borders.
11390 Accepted values are:
11395 optimal static zoom value is determined (only very strong movements
11396 will lead to visible borders) (default)
11398 optimal adaptive zoom value is determined (no borders will be
11399 visible), see @option{zoomspeed}
11402 Note that the value given at zoom is added to the one calculated here.
11405 Set percent to zoom maximally each frame (enabled when
11406 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
11410 Specify type of interpolation.
11412 Available values are:
11417 linear only horizontal
11419 linear in both directions (default)
11421 cubic in both directions (slow)
11425 Enable virtual tripod mode if set to 1, which is equivalent to
11426 @code{relative=0:smoothing=0}. Default value is 0.
11428 Use also @code{tripod} option of @ref{vidstabdetect}.
11431 Increase log verbosity if set to 1. Also the detected global motions
11432 are written to the temporary file @file{global_motions.trf}. Default
11436 @subsection Examples
11440 Use @command{ffmpeg} for a typical stabilization with default values:
11442 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
11445 Note the use of the @ref{unsharp} filter which is always recommended.
11448 Zoom in a bit more and load transform data from a given file:
11450 vidstabtransform=zoom=5:input="mytransforms.trf"
11454 Smoothen the video even more:
11456 vidstabtransform=smoothing=30
11462 Flip the input video vertically.
11464 For example, to vertically flip a video with @command{ffmpeg}:
11466 ffmpeg -i in.avi -vf "vflip" out.avi
11472 Make or reverse a natural vignetting effect.
11474 The filter accepts the following options:
11478 Set lens angle expression as a number of radians.
11480 The value is clipped in the @code{[0,PI/2]} range.
11482 Default value: @code{"PI/5"}
11486 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
11490 Set forward/backward mode.
11492 Available modes are:
11495 The larger the distance from the central point, the darker the image becomes.
11498 The larger the distance from the central point, the brighter the image becomes.
11499 This can be used to reverse a vignette effect, though there is no automatic
11500 detection to extract the lens @option{angle} and other settings (yet). It can
11501 also be used to create a burning effect.
11504 Default value is @samp{forward}.
11507 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
11509 It accepts the following values:
11512 Evaluate expressions only once during the filter initialization.
11515 Evaluate expressions for each incoming frame. This is way slower than the
11516 @samp{init} mode since it requires all the scalers to be re-computed, but it
11517 allows advanced dynamic expressions.
11520 Default value is @samp{init}.
11523 Set dithering to reduce the circular banding effects. Default is @code{1}
11527 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
11528 Setting this value to the SAR of the input will make a rectangular vignetting
11529 following the dimensions of the video.
11531 Default is @code{1/1}.
11534 @subsection Expressions
11536 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
11537 following parameters.
11542 input width and height
11545 the number of input frame, starting from 0
11548 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
11549 @var{TB} units, NAN if undefined
11552 frame rate of the input video, NAN if the input frame rate is unknown
11555 the PTS (Presentation TimeStamp) of the filtered video frame,
11556 expressed in seconds, NAN if undefined
11559 time base of the input video
11563 @subsection Examples
11567 Apply simple strong vignetting effect:
11573 Make a flickering vignetting:
11575 vignette='PI/4+random(1)*PI/50':eval=frame
11581 Stack input videos vertically.
11583 All streams must be of same pixel format and of same width.
11585 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
11586 to create same output.
11588 The filter accept the following option:
11592 Set number of input streams. Default is 2.
11597 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
11598 Deinterlacing Filter").
11600 Based on the process described by Martin Weston for BBC R&D, and
11601 implemented based on the de-interlace algorithm written by Jim
11602 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
11603 uses filter coefficients calculated by BBC R&D.
11605 There are two sets of filter coefficients, so called "simple":
11606 and "complex". Which set of filter coefficients is used can
11607 be set by passing an optional parameter:
11611 Set the interlacing filter coefficients. Accepts one of the following values:
11615 Simple filter coefficient set.
11617 More-complex filter coefficient set.
11619 Default value is @samp{complex}.
11622 Specify which frames to deinterlace. Accept one of the following values:
11626 Deinterlace all frames,
11628 Only deinterlace frames marked as interlaced.
11631 Default value is @samp{all}.
11635 Video waveform monitor.
11637 The waveform monitor plots color component intensity. By default luminance
11638 only. Each column of the waveform corresponds to a column of pixels in the
11641 It accepts the following options:
11645 Can be either @code{row}, or @code{column}. Default is @code{column}.
11646 In row mode, the graph on the left side represents color component value 0 and
11647 the right side represents value = 255. In column mode, the top side represents
11648 color component value = 0 and bottom side represents value = 255.
11651 Set intensity. Smaller values are useful to find out how many values of the same
11652 luminance are distributed across input rows/columns.
11653 Default value is @code{0.04}. Allowed range is [0, 1].
11656 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
11657 In mirrored mode, higher values will be represented on the left
11658 side for @code{row} mode and at the top for @code{column} mode. Default is
11659 @code{1} (mirrored).
11663 It accepts the following values:
11666 Presents information identical to that in the @code{parade}, except
11667 that the graphs representing color components are superimposed directly
11670 This display mode makes it easier to spot relative differences or similarities
11671 in overlapping areas of the color components that are supposed to be identical,
11672 such as neutral whites, grays, or blacks.
11675 Display separate graph for the color components side by side in
11676 @code{row} mode or one below the other in @code{column} mode.
11678 Using this display mode makes it easy to spot color casts in the highlights
11679 and shadows of an image, by comparing the contours of the top and the bottom
11680 graphs of each waveform. Since whites, grays, and blacks are characterized
11681 by exactly equal amounts of red, green, and blue, neutral areas of the picture
11682 should display three waveforms of roughly equal width/height. If not, the
11683 correction is easy to perform by making level adjustments the three waveforms.
11685 Default is @code{parade}.
11687 @item components, c
11688 Set which color components to display. Default is 1, which means only luminance
11689 or red color component if input is in RGB colorspace. If is set for example to
11690 7 it will display all 3 (if) available color components.
11695 No envelope, this is default.
11698 Instant envelope, minimum and maximum values presented in graph will be easily
11699 visible even with small @code{step} value.
11702 Hold minimum and maximum values presented in graph across time. This way you
11703 can still spot out of range values without constantly looking at waveforms.
11706 Peak and instant envelope combined together.
11712 No filtering, this is default.
11715 Luma and chroma combined together.
11718 Similar as above, but shows difference between blue and red chroma.
11721 Displays only chroma.
11724 Similar as above, but shows difference between blue and red chroma.
11727 Displays actual color value on waveform.
11732 Apply the xBR high-quality magnification filter which is designed for pixel
11733 art. It follows a set of edge-detection rules, see
11734 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
11736 It accepts the following option:
11740 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
11741 @code{3xBR} and @code{4} for @code{4xBR}.
11742 Default is @code{3}.
11748 Deinterlace the input video ("yadif" means "yet another deinterlacing
11751 It accepts the following parameters:
11757 The interlacing mode to adopt. It accepts one of the following values:
11760 @item 0, send_frame
11761 Output one frame for each frame.
11762 @item 1, send_field
11763 Output one frame for each field.
11764 @item 2, send_frame_nospatial
11765 Like @code{send_frame}, but it skips the spatial interlacing check.
11766 @item 3, send_field_nospatial
11767 Like @code{send_field}, but it skips the spatial interlacing check.
11770 The default value is @code{send_frame}.
11773 The picture field parity assumed for the input interlaced video. It accepts one
11774 of the following values:
11778 Assume the top field is first.
11780 Assume the bottom field is first.
11782 Enable automatic detection of field parity.
11785 The default value is @code{auto}.
11786 If the interlacing is unknown or the decoder does not export this information,
11787 top field first will be assumed.
11790 Specify which frames to deinterlace. Accept one of the following
11795 Deinterlace all frames.
11796 @item 1, interlaced
11797 Only deinterlace frames marked as interlaced.
11800 The default value is @code{all}.
11805 Apply Zoom & Pan effect.
11807 This filter accepts the following options:
11811 Set the zoom expression. Default is 1.
11815 Set the x and y expression. Default is 0.
11818 Set the duration expression in number of frames.
11819 This sets for how many number of frames effect will last for
11820 single input image.
11823 Set the output image size, default is 'hd720'.
11826 Each expression can contain the following constants:
11845 Output frame count.
11849 Last calculated 'x' and 'y' position from 'x' and 'y' expression
11850 for current input frame.
11854 'x' and 'y' of last output frame of previous input frame or 0 when there was
11855 not yet such frame (first input frame).
11858 Last calculated zoom from 'z' expression for current input frame.
11861 Last calculated zoom of last output frame of previous input frame.
11864 Number of output frames for current input frame. Calculated from 'd' expression
11865 for each input frame.
11868 number of output frames created for previous input frame
11871 Rational number: input width / input height
11874 sample aspect ratio
11877 display aspect ratio
11881 @subsection Examples
11885 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
11887 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
11891 Zoom-in up to 1.5 and pan always at center of picture:
11893 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
11898 Scale (resize) the input video, using the z.lib library:
11899 https://github.com/sekrit-twc/zimg.
11901 The zscale filter forces the output display aspect ratio to be the same
11902 as the input, by changing the output sample aspect ratio.
11904 If the input image format is different from the format requested by
11905 the next filter, the zscale filter will convert the input to the
11908 @subsection Options
11909 The filter accepts the following options.
11914 Set the output video dimension expression. Default value is the input
11917 If the @var{width} or @var{w} is 0, the input width is used for the output.
11918 If the @var{height} or @var{h} is 0, the input height is used for the output.
11920 If one of the values is -1, the zscale filter will use a value that
11921 maintains the aspect ratio of the input image, calculated from the
11922 other specified dimension. If both of them are -1, the input size is
11925 If one of the values is -n with n > 1, the zscale filter will also use a value
11926 that maintains the aspect ratio of the input image, calculated from the other
11927 specified dimension. After that it will, however, make sure that the calculated
11928 dimension is divisible by n and adjust the value if necessary.
11930 See below for the list of accepted constants for use in the dimension
11934 Set the video size. For the syntax of this option, check the
11935 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11938 Set the dither type.
11940 Possible values are:
11945 @item error_diffusion
11951 Set the resize filter type.
11953 Possible values are:
11963 Default is bilinear.
11966 Set the color range.
11968 Possible values are:
11975 Default is same as input.
11978 Set the color primaries.
11980 Possible values are:
11990 Default is same as input.
11993 Set the transfer characteristics.
11995 Possible values are:
12006 Default is same as input.
12009 Set the colorspace matrix.
12011 Possible value are:
12022 Default is same as input.
12025 The values of the @option{w} and @option{h} options are expressions
12026 containing the following constants:
12031 The input width and height
12035 These are the same as @var{in_w} and @var{in_h}.
12039 The output (scaled) width and height
12043 These are the same as @var{out_w} and @var{out_h}
12046 The same as @var{iw} / @var{ih}
12049 input sample aspect ratio
12052 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
12056 horizontal and vertical input chroma subsample values. For example for the
12057 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
12061 horizontal and vertical output chroma subsample values. For example for the
12062 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
12068 @c man end VIDEO FILTERS
12070 @chapter Video Sources
12071 @c man begin VIDEO SOURCES
12073 Below is a description of the currently available video sources.
12077 Buffer video frames, and make them available to the filter chain.
12079 This source is mainly intended for a programmatic use, in particular
12080 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
12082 It accepts the following parameters:
12087 Specify the size (width and height) of the buffered video frames. For the
12088 syntax of this option, check the
12089 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12092 The input video width.
12095 The input video height.
12098 A string representing the pixel format of the buffered video frames.
12099 It may be a number corresponding to a pixel format, or a pixel format
12103 Specify the timebase assumed by the timestamps of the buffered frames.
12106 Specify the frame rate expected for the video stream.
12108 @item pixel_aspect, sar
12109 The sample (pixel) aspect ratio of the input video.
12112 Specify the optional parameters to be used for the scale filter which
12113 is automatically inserted when an input change is detected in the
12114 input size or format.
12119 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
12122 will instruct the source to accept video frames with size 320x240 and
12123 with format "yuv410p", assuming 1/24 as the timestamps timebase and
12124 square pixels (1:1 sample aspect ratio).
12125 Since the pixel format with name "yuv410p" corresponds to the number 6
12126 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
12127 this example corresponds to:
12129 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
12132 Alternatively, the options can be specified as a flat string, but this
12133 syntax is deprecated:
12135 @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}]
12139 Create a pattern generated by an elementary cellular automaton.
12141 The initial state of the cellular automaton can be defined through the
12142 @option{filename}, and @option{pattern} options. If such options are
12143 not specified an initial state is created randomly.
12145 At each new frame a new row in the video is filled with the result of
12146 the cellular automaton next generation. The behavior when the whole
12147 frame is filled is defined by the @option{scroll} option.
12149 This source accepts the following options:
12153 Read the initial cellular automaton state, i.e. the starting row, from
12154 the specified file.
12155 In the file, each non-whitespace character is considered an alive
12156 cell, a newline will terminate the row, and further characters in the
12157 file will be ignored.
12160 Read the initial cellular automaton state, i.e. the starting row, from
12161 the specified string.
12163 Each non-whitespace character in the string is considered an alive
12164 cell, a newline will terminate the row, and further characters in the
12165 string will be ignored.
12168 Set the video rate, that is the number of frames generated per second.
12171 @item random_fill_ratio, ratio
12172 Set the random fill ratio for the initial cellular automaton row. It
12173 is a floating point number value ranging from 0 to 1, defaults to
12176 This option is ignored when a file or a pattern is specified.
12178 @item random_seed, seed
12179 Set the seed for filling randomly the initial row, must be an integer
12180 included between 0 and UINT32_MAX. If not specified, or if explicitly
12181 set to -1, the filter will try to use a good random seed on a best
12185 Set the cellular automaton rule, it is a number ranging from 0 to 255.
12186 Default value is 110.
12189 Set the size of the output video. For the syntax of this option, check the
12190 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12192 If @option{filename} or @option{pattern} is specified, the size is set
12193 by default to the width of the specified initial state row, and the
12194 height is set to @var{width} * PHI.
12196 If @option{size} is set, it must contain the width of the specified
12197 pattern string, and the specified pattern will be centered in the
12200 If a filename or a pattern string is not specified, the size value
12201 defaults to "320x518" (used for a randomly generated initial state).
12204 If set to 1, scroll the output upward when all the rows in the output
12205 have been already filled. If set to 0, the new generated row will be
12206 written over the top row just after the bottom row is filled.
12209 @item start_full, full
12210 If set to 1, completely fill the output with generated rows before
12211 outputting the first frame.
12212 This is the default behavior, for disabling set the value to 0.
12215 If set to 1, stitch the left and right row edges together.
12216 This is the default behavior, for disabling set the value to 0.
12219 @subsection Examples
12223 Read the initial state from @file{pattern}, and specify an output of
12226 cellauto=f=pattern:s=200x400
12230 Generate a random initial row with a width of 200 cells, with a fill
12233 cellauto=ratio=2/3:s=200x200
12237 Create a pattern generated by rule 18 starting by a single alive cell
12238 centered on an initial row with width 100:
12240 cellauto=p=@@:s=100x400:full=0:rule=18
12244 Specify a more elaborated initial pattern:
12246 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
12251 @section mandelbrot
12253 Generate a Mandelbrot set fractal, and progressively zoom towards the
12254 point specified with @var{start_x} and @var{start_y}.
12256 This source accepts the following options:
12261 Set the terminal pts value. Default value is 400.
12264 Set the terminal scale value.
12265 Must be a floating point value. Default value is 0.3.
12268 Set the inner coloring mode, that is the algorithm used to draw the
12269 Mandelbrot fractal internal region.
12271 It shall assume one of the following values:
12276 Show time until convergence.
12278 Set color based on point closest to the origin of the iterations.
12283 Default value is @var{mincol}.
12286 Set the bailout value. Default value is 10.0.
12289 Set the maximum of iterations performed by the rendering
12290 algorithm. Default value is 7189.
12293 Set outer coloring mode.
12294 It shall assume one of following values:
12296 @item iteration_count
12297 Set iteration cound mode.
12298 @item normalized_iteration_count
12299 set normalized iteration count mode.
12301 Default value is @var{normalized_iteration_count}.
12304 Set frame rate, expressed as number of frames per second. Default
12308 Set frame size. For the syntax of this option, check the "Video
12309 size" section in the ffmpeg-utils manual. Default value is "640x480".
12312 Set the initial scale value. Default value is 3.0.
12315 Set the initial x position. Must be a floating point value between
12316 -100 and 100. Default value is -0.743643887037158704752191506114774.
12319 Set the initial y position. Must be a floating point value between
12320 -100 and 100. Default value is -0.131825904205311970493132056385139.
12325 Generate various test patterns, as generated by the MPlayer test filter.
12327 The size of the generated video is fixed, and is 256x256.
12328 This source is useful in particular for testing encoding features.
12330 This source accepts the following options:
12335 Specify the frame rate of the sourced video, as the number of frames
12336 generated per second. It has to be a string in the format
12337 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
12338 number or a valid video frame rate abbreviation. The default value is
12342 Set the duration of the sourced video. See
12343 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
12344 for the accepted syntax.
12346 If not specified, or the expressed duration is negative, the video is
12347 supposed to be generated forever.
12351 Set the number or the name of the test to perform. Supported tests are:
12367 Default value is "all", which will cycle through the list of all tests.
12372 mptestsrc=t=dc_luma
12375 will generate a "dc_luma" test pattern.
12377 @section frei0r_src
12379 Provide a frei0r source.
12381 To enable compilation of this filter you need to install the frei0r
12382 header and configure FFmpeg with @code{--enable-frei0r}.
12384 This source accepts the following parameters:
12389 The size of the video to generate. For the syntax of this option, check the
12390 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12393 The framerate of the generated video. It may be a string of the form
12394 @var{num}/@var{den} or a frame rate abbreviation.
12397 The name to the frei0r source to load. For more information regarding frei0r and
12398 how to set the parameters, read the @ref{frei0r} section in the video filters
12401 @item filter_params
12402 A '|'-separated list of parameters to pass to the frei0r source.
12406 For example, to generate a frei0r partik0l source with size 200x200
12407 and frame rate 10 which is overlaid on the overlay filter main input:
12409 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
12414 Generate a life pattern.
12416 This source is based on a generalization of John Conway's life game.
12418 The sourced input represents a life grid, each pixel represents a cell
12419 which can be in one of two possible states, alive or dead. Every cell
12420 interacts with its eight neighbours, which are the cells that are
12421 horizontally, vertically, or diagonally adjacent.
12423 At each interaction the grid evolves according to the adopted rule,
12424 which specifies the number of neighbor alive cells which will make a
12425 cell stay alive or born. The @option{rule} option allows one to specify
12428 This source accepts the following options:
12432 Set the file from which to read the initial grid state. In the file,
12433 each non-whitespace character is considered an alive cell, and newline
12434 is used to delimit the end of each row.
12436 If this option is not specified, the initial grid is generated
12440 Set the video rate, that is the number of frames generated per second.
12443 @item random_fill_ratio, ratio
12444 Set the random fill ratio for the initial random grid. It is a
12445 floating point number value ranging from 0 to 1, defaults to 1/PHI.
12446 It is ignored when a file is specified.
12448 @item random_seed, seed
12449 Set the seed for filling the initial random grid, must be an integer
12450 included between 0 and UINT32_MAX. If not specified, or if explicitly
12451 set to -1, the filter will try to use a good random seed on a best
12457 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
12458 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
12459 @var{NS} specifies the number of alive neighbor cells which make a
12460 live cell stay alive, and @var{NB} the number of alive neighbor cells
12461 which make a dead cell to become alive (i.e. to "born").
12462 "s" and "b" can be used in place of "S" and "B", respectively.
12464 Alternatively a rule can be specified by an 18-bits integer. The 9
12465 high order bits are used to encode the next cell state if it is alive
12466 for each number of neighbor alive cells, the low order bits specify
12467 the rule for "borning" new cells. Higher order bits encode for an
12468 higher number of neighbor cells.
12469 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
12470 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
12472 Default value is "S23/B3", which is the original Conway's game of life
12473 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
12474 cells, and will born a new cell if there are three alive cells around
12478 Set the size of the output video. For the syntax of this option, check the
12479 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12481 If @option{filename} is specified, the size is set by default to the
12482 same size of the input file. If @option{size} is set, it must contain
12483 the size specified in the input file, and the initial grid defined in
12484 that file is centered in the larger resulting area.
12486 If a filename is not specified, the size value defaults to "320x240"
12487 (used for a randomly generated initial grid).
12490 If set to 1, stitch the left and right grid edges together, and the
12491 top and bottom edges also. Defaults to 1.
12494 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
12495 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
12496 value from 0 to 255.
12499 Set the color of living (or new born) cells.
12502 Set the color of dead cells. If @option{mold} is set, this is the first color
12503 used to represent a dead cell.
12506 Set mold color, for definitely dead and moldy cells.
12508 For the syntax of these 3 color options, check the "Color" section in the
12509 ffmpeg-utils manual.
12512 @subsection Examples
12516 Read a grid from @file{pattern}, and center it on a grid of size
12519 life=f=pattern:s=300x300
12523 Generate a random grid of size 200x200, with a fill ratio of 2/3:
12525 life=ratio=2/3:s=200x200
12529 Specify a custom rule for evolving a randomly generated grid:
12535 Full example with slow death effect (mold) using @command{ffplay}:
12537 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
12544 @anchor{haldclutsrc}
12546 @anchor{rgbtestsrc}
12548 @anchor{smptehdbars}
12550 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
12552 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
12554 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
12556 The @code{color} source provides an uniformly colored input.
12558 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
12559 @ref{haldclut} filter.
12561 The @code{nullsrc} source returns unprocessed video frames. It is
12562 mainly useful to be employed in analysis / debugging tools, or as the
12563 source for filters which ignore the input data.
12565 The @code{rgbtestsrc} source generates an RGB test pattern useful for
12566 detecting RGB vs BGR issues. You should see a red, green and blue
12567 stripe from top to bottom.
12569 The @code{smptebars} source generates a color bars pattern, based on
12570 the SMPTE Engineering Guideline EG 1-1990.
12572 The @code{smptehdbars} source generates a color bars pattern, based on
12573 the SMPTE RP 219-2002.
12575 The @code{testsrc} source generates a test video pattern, showing a
12576 color pattern, a scrolling gradient and a timestamp. This is mainly
12577 intended for testing purposes.
12579 The sources accept the following parameters:
12584 Specify the color of the source, only available in the @code{color}
12585 source. For the syntax of this option, check the "Color" section in the
12586 ffmpeg-utils manual.
12589 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
12590 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
12591 pixels to be used as identity matrix for 3D lookup tables. Each component is
12592 coded on a @code{1/(N*N)} scale.
12595 Specify the size of the sourced video. For the syntax of this option, check the
12596 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12597 The default value is @code{320x240}.
12599 This option is not available with the @code{haldclutsrc} filter.
12602 Specify the frame rate of the sourced video, as the number of frames
12603 generated per second. It has to be a string in the format
12604 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
12605 number or a valid video frame rate abbreviation. The default value is
12609 Set the sample aspect ratio of the sourced video.
12612 Set the duration of the sourced video. See
12613 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
12614 for the accepted syntax.
12616 If not specified, or the expressed duration is negative, the video is
12617 supposed to be generated forever.
12620 Set the number of decimals to show in the timestamp, only available in the
12621 @code{testsrc} source.
12623 The displayed timestamp value will correspond to the original
12624 timestamp value multiplied by the power of 10 of the specified
12625 value. Default value is 0.
12628 For example the following:
12630 testsrc=duration=5.3:size=qcif:rate=10
12633 will generate a video with a duration of 5.3 seconds, with size
12634 176x144 and a frame rate of 10 frames per second.
12636 The following graph description will generate a red source
12637 with an opacity of 0.2, with size "qcif" and a frame rate of 10
12640 color=c=red@@0.2:s=qcif:r=10
12643 If the input content is to be ignored, @code{nullsrc} can be used. The
12644 following command generates noise in the luminance plane by employing
12645 the @code{geq} filter:
12647 nullsrc=s=256x256, geq=random(1)*255:128:128
12650 @subsection Commands
12652 The @code{color} source supports the following commands:
12656 Set the color of the created image. Accepts the same syntax of the
12657 corresponding @option{color} option.
12660 @c man end VIDEO SOURCES
12662 @chapter Video Sinks
12663 @c man begin VIDEO SINKS
12665 Below is a description of the currently available video sinks.
12667 @section buffersink
12669 Buffer video frames, and make them available to the end of the filter
12672 This sink is mainly intended for programmatic use, in particular
12673 through the interface defined in @file{libavfilter/buffersink.h}
12674 or the options system.
12676 It accepts a pointer to an AVBufferSinkContext structure, which
12677 defines the incoming buffers' formats, to be passed as the opaque
12678 parameter to @code{avfilter_init_filter} for initialization.
12682 Null video sink: do absolutely nothing with the input video. It is
12683 mainly useful as a template and for use in analysis / debugging
12686 @c man end VIDEO SINKS
12688 @chapter Multimedia Filters
12689 @c man begin MULTIMEDIA FILTERS
12691 Below is a description of the currently available multimedia filters.
12693 @section aphasemeter
12695 Convert input audio to a video output, displaying the audio phase.
12697 The filter accepts the following options:
12701 Set the output frame rate. Default value is @code{25}.
12704 Set the video size for the output. For the syntax of this option, check the
12705 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12706 Default value is @code{800x400}.
12711 Specify the red, green, blue contrast. Default values are @code{2},
12712 @code{7} and @code{1}.
12713 Allowed range is @code{[0, 255]}.
12716 Set color which will be used for drawing median phase. If color is
12717 @code{none} which is default, no median phase value will be drawn.
12720 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
12721 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
12722 The @code{-1} means left and right channels are completely out of phase and
12723 @code{1} means channels are in phase.
12725 @section avectorscope
12727 Convert input audio to a video output, representing the audio vector
12730 The filter is used to measure the difference between channels of stereo
12731 audio stream. A monoaural signal, consisting of identical left and right
12732 signal, results in straight vertical line. Any stereo separation is visible
12733 as a deviation from this line, creating a Lissajous figure.
12734 If the straight (or deviation from it) but horizontal line appears this
12735 indicates that the left and right channels are out of phase.
12737 The filter accepts the following options:
12741 Set the vectorscope mode.
12743 Available values are:
12746 Lissajous rotated by 45 degrees.
12749 Same as above but not rotated.
12752 Shape resembling half of circle.
12755 Default value is @samp{lissajous}.
12758 Set the video size for the output. For the syntax of this option, check the
12759 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12760 Default value is @code{400x400}.
12763 Set the output frame rate. Default value is @code{25}.
12769 Specify the red, green, blue and alpha contrast. Default values are @code{40},
12770 @code{160}, @code{80} and @code{255}.
12771 Allowed range is @code{[0, 255]}.
12777 Specify the red, green, blue and alpha fade. Default values are @code{15},
12778 @code{10}, @code{5} and @code{5}.
12779 Allowed range is @code{[0, 255]}.
12782 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
12785 @subsection Examples
12789 Complete example using @command{ffplay}:
12791 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
12792 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
12798 Concatenate audio and video streams, joining them together one after the
12801 The filter works on segments of synchronized video and audio streams. All
12802 segments must have the same number of streams of each type, and that will
12803 also be the number of streams at output.
12805 The filter accepts the following options:
12810 Set the number of segments. Default is 2.
12813 Set the number of output video streams, that is also the number of video
12814 streams in each segment. Default is 1.
12817 Set the number of output audio streams, that is also the number of audio
12818 streams in each segment. Default is 0.
12821 Activate unsafe mode: do not fail if segments have a different format.
12825 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
12826 @var{a} audio outputs.
12828 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
12829 segment, in the same order as the outputs, then the inputs for the second
12832 Related streams do not always have exactly the same duration, for various
12833 reasons including codec frame size or sloppy authoring. For that reason,
12834 related synchronized streams (e.g. a video and its audio track) should be
12835 concatenated at once. The concat filter will use the duration of the longest
12836 stream in each segment (except the last one), and if necessary pad shorter
12837 audio streams with silence.
12839 For this filter to work correctly, all segments must start at timestamp 0.
12841 All corresponding streams must have the same parameters in all segments; the
12842 filtering system will automatically select a common pixel format for video
12843 streams, and a common sample format, sample rate and channel layout for
12844 audio streams, but other settings, such as resolution, must be converted
12845 explicitly by the user.
12847 Different frame rates are acceptable but will result in variable frame rate
12848 at output; be sure to configure the output file to handle it.
12850 @subsection Examples
12854 Concatenate an opening, an episode and an ending, all in bilingual version
12855 (video in stream 0, audio in streams 1 and 2):
12857 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
12858 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
12859 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
12860 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
12864 Concatenate two parts, handling audio and video separately, using the
12865 (a)movie sources, and adjusting the resolution:
12867 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
12868 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
12869 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
12871 Note that a desync will happen at the stitch if the audio and video streams
12872 do not have exactly the same duration in the first file.
12879 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
12880 it unchanged. By default, it logs a message at a frequency of 10Hz with the
12881 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
12882 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
12884 The filter also has a video output (see the @var{video} option) with a real
12885 time graph to observe the loudness evolution. The graphic contains the logged
12886 message mentioned above, so it is not printed anymore when this option is set,
12887 unless the verbose logging is set. The main graphing area contains the
12888 short-term loudness (3 seconds of analysis), and the gauge on the right is for
12889 the momentary loudness (400 milliseconds).
12891 More information about the Loudness Recommendation EBU R128 on
12892 @url{http://tech.ebu.ch/loudness}.
12894 The filter accepts the following options:
12899 Activate the video output. The audio stream is passed unchanged whether this
12900 option is set or no. The video stream will be the first output stream if
12901 activated. Default is @code{0}.
12904 Set the video size. This option is for video only. For the syntax of this
12906 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12907 Default and minimum resolution is @code{640x480}.
12910 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
12911 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
12912 other integer value between this range is allowed.
12915 Set metadata injection. If set to @code{1}, the audio input will be segmented
12916 into 100ms output frames, each of them containing various loudness information
12917 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
12919 Default is @code{0}.
12922 Force the frame logging level.
12924 Available values are:
12927 information logging level
12929 verbose logging level
12932 By default, the logging level is set to @var{info}. If the @option{video} or
12933 the @option{metadata} options are set, it switches to @var{verbose}.
12938 Available modes can be cumulated (the option is a @code{flag} type). Possible
12942 Disable any peak mode (default).
12944 Enable sample-peak mode.
12946 Simple peak mode looking for the higher sample value. It logs a message
12947 for sample-peak (identified by @code{SPK}).
12949 Enable true-peak mode.
12951 If enabled, the peak lookup is done on an over-sampled version of the input
12952 stream for better peak accuracy. It logs a message for true-peak.
12953 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
12954 This mode requires a build with @code{libswresample}.
12958 Treat mono input files as "dual mono". If a mono file is intended for playback
12959 on a stereo system, its EBU R128 measurement will be perceptually incorrect.
12960 If set to @code{true}, this option will compensate for this effect.
12961 Multi-channel input files are not affected by this option.
12964 Set a specific pan law to be used for the measurement of dual mono files.
12965 This parameter is optional, and has a default value of -3.01dB.
12968 @subsection Examples
12972 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
12974 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
12978 Run an analysis with @command{ffmpeg}:
12980 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
12984 @section interleave, ainterleave
12986 Temporally interleave frames from several inputs.
12988 @code{interleave} works with video inputs, @code{ainterleave} with audio.
12990 These filters read frames from several inputs and send the oldest
12991 queued frame to the output.
12993 Input streams must have a well defined, monotonically increasing frame
12996 In order to submit one frame to output, these filters need to enqueue
12997 at least one frame for each input, so they cannot work in case one
12998 input is not yet terminated and will not receive incoming frames.
13000 For example consider the case when one input is a @code{select} filter
13001 which always drop input frames. The @code{interleave} filter will keep
13002 reading from that input, but it will never be able to send new frames
13003 to output until the input will send an end-of-stream signal.
13005 Also, depending on inputs synchronization, the filters will drop
13006 frames in case one input receives more frames than the other ones, and
13007 the queue is already filled.
13009 These filters accept the following options:
13013 Set the number of different inputs, it is 2 by default.
13016 @subsection Examples
13020 Interleave frames belonging to different streams using @command{ffmpeg}:
13022 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
13026 Add flickering blur effect:
13028 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
13032 @section perms, aperms
13034 Set read/write permissions for the output frames.
13036 These filters are mainly aimed at developers to test direct path in the
13037 following filter in the filtergraph.
13039 The filters accept the following options:
13043 Select the permissions mode.
13045 It accepts the following values:
13048 Do nothing. This is the default.
13050 Set all the output frames read-only.
13052 Set all the output frames directly writable.
13054 Make the frame read-only if writable, and writable if read-only.
13056 Set each output frame read-only or writable randomly.
13060 Set the seed for the @var{random} mode, must be an integer included between
13061 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
13062 @code{-1}, the filter will try to use a good random seed on a best effort
13066 Note: in case of auto-inserted filter between the permission filter and the
13067 following one, the permission might not be received as expected in that
13068 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
13069 perms/aperms filter can avoid this problem.
13071 @section select, aselect
13073 Select frames to pass in output.
13075 This filter accepts the following options:
13080 Set expression, which is evaluated for each input frame.
13082 If the expression is evaluated to zero, the frame is discarded.
13084 If the evaluation result is negative or NaN, the frame is sent to the
13085 first output; otherwise it is sent to the output with index
13086 @code{ceil(val)-1}, assuming that the input index starts from 0.
13088 For example a value of @code{1.2} corresponds to the output with index
13089 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
13092 Set the number of outputs. The output to which to send the selected
13093 frame is based on the result of the evaluation. Default value is 1.
13096 The expression can contain the following constants:
13100 The (sequential) number of the filtered frame, starting from 0.
13103 The (sequential) number of the selected frame, starting from 0.
13105 @item prev_selected_n
13106 The sequential number of the last selected frame. It's NAN if undefined.
13109 The timebase of the input timestamps.
13112 The PTS (Presentation TimeStamp) of the filtered video frame,
13113 expressed in @var{TB} units. It's NAN if undefined.
13116 The PTS of the filtered video frame,
13117 expressed in seconds. It's NAN if undefined.
13120 The PTS of the previously filtered video frame. It's NAN if undefined.
13122 @item prev_selected_pts
13123 The PTS of the last previously filtered video frame. It's NAN if undefined.
13125 @item prev_selected_t
13126 The PTS of the last previously selected video frame. It's NAN if undefined.
13129 The PTS of the first video frame in the video. It's NAN if undefined.
13132 The time of the first video frame in the video. It's NAN if undefined.
13134 @item pict_type @emph{(video only)}
13135 The type of the filtered frame. It can assume one of the following
13147 @item interlace_type @emph{(video only)}
13148 The frame interlace type. It can assume one of the following values:
13151 The frame is progressive (not interlaced).
13153 The frame is top-field-first.
13155 The frame is bottom-field-first.
13158 @item consumed_sample_n @emph{(audio only)}
13159 the number of selected samples before the current frame
13161 @item samples_n @emph{(audio only)}
13162 the number of samples in the current frame
13164 @item sample_rate @emph{(audio only)}
13165 the input sample rate
13168 This is 1 if the filtered frame is a key-frame, 0 otherwise.
13171 the position in the file of the filtered frame, -1 if the information
13172 is not available (e.g. for synthetic video)
13174 @item scene @emph{(video only)}
13175 value between 0 and 1 to indicate a new scene; a low value reflects a low
13176 probability for the current frame to introduce a new scene, while a higher
13177 value means the current frame is more likely to be one (see the example below)
13181 The default value of the select expression is "1".
13183 @subsection Examples
13187 Select all frames in input:
13192 The example above is the same as:
13204 Select only I-frames:
13206 select='eq(pict_type\,I)'
13210 Select one frame every 100:
13212 select='not(mod(n\,100))'
13216 Select only frames contained in the 10-20 time interval:
13218 select=between(t\,10\,20)
13222 Select only I frames contained in the 10-20 time interval:
13224 select=between(t\,10\,20)*eq(pict_type\,I)
13228 Select frames with a minimum distance of 10 seconds:
13230 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
13234 Use aselect to select only audio frames with samples number > 100:
13236 aselect='gt(samples_n\,100)'
13240 Create a mosaic of the first scenes:
13242 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
13245 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
13249 Send even and odd frames to separate outputs, and compose them:
13251 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
13255 @section selectivecolor
13257 Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such
13258 as "reds", "yellows", "greens", "cyans", ...). The adjustment range is defined
13259 by the "purity" of the color (that is, how saturated it already is).
13261 This filter is similar to the Adobe Photoshop Selective Color tool.
13263 The filter accepts the following options:
13266 @item correction_method
13267 Select color correction method.
13269 Available values are:
13272 Specified adjustments are applied "as-is" (added/subtracted to original pixel
13275 Specified adjustments are relative to the original component value.
13277 Default is @code{absolute}.
13279 Adjustments for red pixels (pixels where the red component is the maximum)
13281 Adjustments for yellow pixels (pixels where the blue component is the minimum)
13283 Adjustments for green pixels (pixels where the green component is the maximum)
13285 Adjustments for cyan pixels (pixels where the red component is the minimum)
13287 Adjustments for blue pixels (pixels where the blue component is the maximum)
13289 Adjustments for magenta pixels (pixels where the green component is the minimum)
13291 Adjustments for white pixels (pixels where all components are greater than 128)
13293 Adjustments for all pixels except pure black and pure white
13295 Adjustments for black pixels (pixels where all components are lesser than 128)
13297 Specify a Photoshop selective color file (@code{.asv}) to import the settings from.
13300 All the adjustment settings (@option{reds}, @option{yellows}, ...) accept up to
13301 4 space separated floating point adjustment values in the [-1,1] range,
13302 respectively to adjust the amount of cyan, magenta, yellow and black for the
13303 pixels of its range.
13305 @subsection Examples
13309 Increase cyan by 50% and reduce yellow by 33% in every green areas, and
13310 increase magenta by 27% in blue areas:
13312 selectivecolor=greens=.5 0 -.33 0:blues=0 .27
13316 Use a Photoshop selective color preset:
13318 selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
13322 @section sendcmd, asendcmd
13324 Send commands to filters in the filtergraph.
13326 These filters read commands to be sent to other filters in the
13329 @code{sendcmd} must be inserted between two video filters,
13330 @code{asendcmd} must be inserted between two audio filters, but apart
13331 from that they act the same way.
13333 The specification of commands can be provided in the filter arguments
13334 with the @var{commands} option, or in a file specified by the
13335 @var{filename} option.
13337 These filters accept the following options:
13340 Set the commands to be read and sent to the other filters.
13342 Set the filename of the commands to be read and sent to the other
13346 @subsection Commands syntax
13348 A commands description consists of a sequence of interval
13349 specifications, comprising a list of commands to be executed when a
13350 particular event related to that interval occurs. The occurring event
13351 is typically the current frame time entering or leaving a given time
13354 An interval is specified by the following syntax:
13356 @var{START}[-@var{END}] @var{COMMANDS};
13359 The time interval is specified by the @var{START} and @var{END} times.
13360 @var{END} is optional and defaults to the maximum time.
13362 The current frame time is considered within the specified interval if
13363 it is included in the interval [@var{START}, @var{END}), that is when
13364 the time is greater or equal to @var{START} and is lesser than
13367 @var{COMMANDS} consists of a sequence of one or more command
13368 specifications, separated by ",", relating to that interval. The
13369 syntax of a command specification is given by:
13371 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
13374 @var{FLAGS} is optional and specifies the type of events relating to
13375 the time interval which enable sending the specified command, and must
13376 be a non-null sequence of identifier flags separated by "+" or "|" and
13377 enclosed between "[" and "]".
13379 The following flags are recognized:
13382 The command is sent when the current frame timestamp enters the
13383 specified interval. In other words, the command is sent when the
13384 previous frame timestamp was not in the given interval, and the
13388 The command is sent when the current frame timestamp leaves the
13389 specified interval. In other words, the command is sent when the
13390 previous frame timestamp was in the given interval, and the
13394 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
13397 @var{TARGET} specifies the target of the command, usually the name of
13398 the filter class or a specific filter instance name.
13400 @var{COMMAND} specifies the name of the command for the target filter.
13402 @var{ARG} is optional and specifies the optional list of argument for
13403 the given @var{COMMAND}.
13405 Between one interval specification and another, whitespaces, or
13406 sequences of characters starting with @code{#} until the end of line,
13407 are ignored and can be used to annotate comments.
13409 A simplified BNF description of the commands specification syntax
13412 @var{COMMAND_FLAG} ::= "enter" | "leave"
13413 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
13414 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
13415 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
13416 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
13417 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
13420 @subsection Examples
13424 Specify audio tempo change at second 4:
13426 asendcmd=c='4.0 atempo tempo 1.5',atempo
13430 Specify a list of drawtext and hue commands in a file.
13432 # show text in the interval 5-10
13433 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
13434 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
13436 # desaturate the image in the interval 15-20
13437 15.0-20.0 [enter] hue s 0,
13438 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
13440 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
13442 # apply an exponential saturation fade-out effect, starting from time 25
13443 25 [enter] hue s exp(25-t)
13446 A filtergraph allowing to read and process the above command list
13447 stored in a file @file{test.cmd}, can be specified with:
13449 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
13454 @section setpts, asetpts
13456 Change the PTS (presentation timestamp) of the input frames.
13458 @code{setpts} works on video frames, @code{asetpts} on audio frames.
13460 This filter accepts the following options:
13465 The expression which is evaluated for each frame to construct its timestamp.
13469 The expression is evaluated through the eval API and can contain the following
13474 frame rate, only defined for constant frame-rate video
13477 The presentation timestamp in input
13480 The count of the input frame for video or the number of consumed samples,
13481 not including the current frame for audio, starting from 0.
13483 @item NB_CONSUMED_SAMPLES
13484 The number of consumed samples, not including the current frame (only
13487 @item NB_SAMPLES, S
13488 The number of samples in the current frame (only audio)
13490 @item SAMPLE_RATE, SR
13491 The audio sample rate.
13494 The PTS of the first frame.
13497 the time in seconds of the first frame
13500 State whether the current frame is interlaced.
13503 the time in seconds of the current frame
13506 original position in the file of the frame, or undefined if undefined
13507 for the current frame
13510 The previous input PTS.
13513 previous input time in seconds
13516 The previous output PTS.
13519 previous output time in seconds
13522 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
13526 The wallclock (RTC) time at the start of the movie in microseconds.
13529 The timebase of the input timestamps.
13533 @subsection Examples
13537 Start counting PTS from zero
13539 setpts=PTS-STARTPTS
13543 Apply fast motion effect:
13549 Apply slow motion effect:
13555 Set fixed rate of 25 frames per second:
13561 Set fixed rate 25 fps with some jitter:
13563 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
13567 Apply an offset of 10 seconds to the input PTS:
13573 Generate timestamps from a "live source" and rebase onto the current timebase:
13575 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
13579 Generate timestamps by counting samples:
13586 @section settb, asettb
13588 Set the timebase to use for the output frames timestamps.
13589 It is mainly useful for testing timebase configuration.
13591 It accepts the following parameters:
13596 The expression which is evaluated into the output timebase.
13600 The value for @option{tb} is an arithmetic expression representing a
13601 rational. The expression can contain the constants "AVTB" (the default
13602 timebase), "intb" (the input timebase) and "sr" (the sample rate,
13603 audio only). Default value is "intb".
13605 @subsection Examples
13609 Set the timebase to 1/25:
13615 Set the timebase to 1/10:
13621 Set the timebase to 1001/1000:
13627 Set the timebase to 2*intb:
13633 Set the default timebase value:
13640 Convert input audio to a video output representing
13641 frequency spectrum logarithmically (using constant Q transform with
13642 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
13644 The filter accepts the following options:
13648 Specify transform volume (multiplier) expression. The expression can contain
13651 @item frequency, freq, f
13652 the frequency where transform is evaluated
13653 @item timeclamp, tc
13654 value of timeclamp option
13658 @item a_weighting(f)
13659 A-weighting of equal loudness
13660 @item b_weighting(f)
13661 B-weighting of equal loudness
13662 @item c_weighting(f)
13663 C-weighting of equal loudness
13665 Default value is @code{16}.
13668 Specify transform length expression. The expression can contain variables:
13670 @item frequency, freq, f
13671 the frequency where transform is evaluated
13672 @item timeclamp, tc
13673 value of timeclamp option
13675 Default value is @code{384/f*tc/(384/f+tc)}.
13678 Specify the transform timeclamp. At low frequency, there is trade-off between
13679 accuracy in time domain and frequency domain. If timeclamp is lower,
13680 event in time domain is represented more accurately (such as fast bass drum),
13681 otherwise event in frequency domain is represented more accurately
13682 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
13685 Specify the transform coeffclamp. If coeffclamp is lower, transform is
13686 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
13687 Default value is @code{1.0}.
13690 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
13691 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
13692 Default value is @code{3.0}.
13695 Specify gamma of bargraph. Acceptable value is [1.0, 7.0].
13696 Default value is @code{1.0}.
13699 Specify font file for use with freetype. If not specified, use embedded font.
13702 Specify font color expression. This is arithmetic expression that should return
13703 integer value 0xRRGGBB. The expression can contain variables:
13705 @item frequency, freq, f
13706 the frequency where transform is evaluated
13707 @item timeclamp, tc
13708 value of timeclamp option
13713 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
13714 @item r(x), g(x), b(x)
13715 red, green, and blue value of intensity x
13717 Default value is @code{st(0, (midi(f)-59.5)/12);
13718 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
13719 r(1-ld(1)) + b(ld(1))}
13722 If set to 1 (the default), the video size is 1920x1080 (full HD),
13723 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
13726 Specify video fps. Default value is @code{25}.
13729 Specify number of transform per frame, so there are fps*count transforms
13730 per second. Note that audio data rate must be divisible by fps*count.
13731 Default value is @code{6}.
13735 @subsection Examples
13739 Playing audio while showing the spectrum:
13741 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
13745 Same as above, but with frame rate 30 fps:
13747 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
13751 Playing at 960x540 and lower CPU usage:
13753 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
13757 A1 and its harmonics: A1, A2, (near)E3, A3:
13759 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),
13760 asplit[a][out1]; [a] showcqt [out0]'
13764 Same as above, but with more accuracy in frequency domain (and slower):
13766 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),
13767 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
13771 B-weighting of equal loudness
13773 volume=16*b_weighting(f)
13779 tlength=100/f*tc/(100/f+tc)
13783 Custom fontcolor, C-note is colored green, others are colored blue
13785 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
13789 Custom gamma, now spectrum is linear to the amplitude.
13798 Convert input audio to video output representing the audio power spectrum.
13799 Audio amplitude is on Y-axis while frequency is on X-axis.
13801 The filter accepts the following options:
13805 Specify size of video. For the syntax of this option, check the
13806 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13807 Default is @code{1024x512}.
13811 This set how each frequency bin will be represented.
13813 It accepts the following values:
13819 Default is @code{bar}.
13822 Set amplitude scale.
13824 It accepts the following values:
13838 Default is @code{log}.
13841 Set frequency scale.
13843 It accepts the following values:
13852 Reverse logarithmic scale.
13854 Default is @code{lin}.
13859 It accepts the following values:
13875 Default is @code{w2048}
13878 Set windowing function.
13880 It accepts the following values:
13897 Default is @code{hanning}.
13900 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
13901 which means optimal overlap for selected window function will be picked.
13904 Set time averaging. Setting this to 0 will display current maximal peaks.
13905 Default is @code{1}, which means time averaging is disabled.
13908 Specify list of colors separated by space or by '|' which will be used to
13909 draw channel frequencies. Unrecognized or missing colors will be replaced
13913 @section showspectrum
13915 Convert input audio to a video output, representing the audio frequency
13918 The filter accepts the following options:
13922 Specify the video size for the output. For the syntax of this option, check the
13923 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13924 Default value is @code{640x512}.
13927 Specify how the spectrum should slide along the window.
13929 It accepts the following values:
13932 the samples start again on the left when they reach the right
13934 the samples scroll from right to left
13936 frames are only produced when the samples reach the right
13939 Default value is @code{replace}.
13942 Specify display mode.
13944 It accepts the following values:
13947 all channels are displayed in the same row
13949 all channels are displayed in separate rows
13952 Default value is @samp{combined}.
13955 Specify display color mode.
13957 It accepts the following values:
13960 each channel is displayed in a separate color
13962 each channel is is displayed using the same color scheme
13965 Default value is @samp{channel}.
13968 Specify scale used for calculating intensity color values.
13970 It accepts the following values:
13975 square root, default
13982 Default value is @samp{sqrt}.
13985 Set saturation modifier for displayed colors. Negative values provide
13986 alternative color scheme. @code{0} is no saturation at all.
13987 Saturation must be in [-10.0, 10.0] range.
13988 Default value is @code{1}.
13991 Set window function.
13993 It accepts the following values:
13996 No samples pre-processing (do not expect this to be faster)
14005 Default value is @code{hann}.
14008 The usage is very similar to the showwaves filter; see the examples in that
14011 @subsection Examples
14015 Large window with logarithmic color scaling:
14017 showspectrum=s=1280x480:scale=log
14021 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
14023 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
14024 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
14028 @section showvolume
14030 Convert input audio volume to a video output.
14032 The filter accepts the following options:
14039 Set border width, allowed range is [0, 5]. Default is 1.
14042 Set channel width, allowed range is [40, 1080]. Default is 400.
14045 Set channel height, allowed range is [1, 100]. Default is 20.
14048 Set fade, allowed range is [1, 255]. Default is 20.
14051 Set volume color expression.
14053 The expression can use the following variables:
14057 Current max volume of channel in dB.
14060 Current channel number, starting from 0.
14064 If set, displays channel names. Default is enabled.
14069 Convert input audio to a video output, representing the samples waves.
14071 The filter accepts the following options:
14075 Specify the video size for the output. For the syntax of this option, check the
14076 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14077 Default value is @code{600x240}.
14082 Available values are:
14085 Draw a point for each sample.
14088 Draw a vertical line for each sample.
14091 Draw a point for each sample and a line between them.
14094 Draw a centered vertical line for each sample.
14097 Default value is @code{point}.
14100 Set the number of samples which are printed on the same column. A
14101 larger value will decrease the frame rate. Must be a positive
14102 integer. This option can be set only if the value for @var{rate}
14103 is not explicitly specified.
14106 Set the (approximate) output frame rate. This is done by setting the
14107 option @var{n}. Default value is "25".
14109 @item split_channels
14110 Set if channels should be drawn separately or overlap. Default value is 0.
14114 @subsection Examples
14118 Output the input file audio and the corresponding video representation
14121 amovie=a.mp3,asplit[out0],showwaves[out1]
14125 Create a synthetic signal and show it with showwaves, forcing a
14126 frame rate of 30 frames per second:
14128 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
14132 @section showwavespic
14134 Convert input audio to a single video frame, representing the samples waves.
14136 The filter accepts the following options:
14140 Specify the video size for the output. For the syntax of this option, check the
14141 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14142 Default value is @code{600x240}.
14144 @item split_channels
14145 Set if channels should be drawn separately or overlap. Default value is 0.
14148 @subsection Examples
14152 Extract a channel split representation of the wave form of a whole audio track
14153 in a 1024x800 picture using @command{ffmpeg}:
14155 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
14159 @section split, asplit
14161 Split input into several identical outputs.
14163 @code{asplit} works with audio input, @code{split} with video.
14165 The filter accepts a single parameter which specifies the number of outputs. If
14166 unspecified, it defaults to 2.
14168 @subsection Examples
14172 Create two separate outputs from the same input:
14174 [in] split [out0][out1]
14178 To create 3 or more outputs, you need to specify the number of
14181 [in] asplit=3 [out0][out1][out2]
14185 Create two separate outputs from the same input, one cropped and
14188 [in] split [splitout1][splitout2];
14189 [splitout1] crop=100:100:0:0 [cropout];
14190 [splitout2] pad=200:200:100:100 [padout];
14194 Create 5 copies of the input audio with @command{ffmpeg}:
14196 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
14202 Receive commands sent through a libzmq client, and forward them to
14203 filters in the filtergraph.
14205 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
14206 must be inserted between two video filters, @code{azmq} between two
14209 To enable these filters you need to install the libzmq library and
14210 headers and configure FFmpeg with @code{--enable-libzmq}.
14212 For more information about libzmq see:
14213 @url{http://www.zeromq.org/}
14215 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
14216 receives messages sent through a network interface defined by the
14217 @option{bind_address} option.
14219 The received message must be in the form:
14221 @var{TARGET} @var{COMMAND} [@var{ARG}]
14224 @var{TARGET} specifies the target of the command, usually the name of
14225 the filter class or a specific filter instance name.
14227 @var{COMMAND} specifies the name of the command for the target filter.
14229 @var{ARG} is optional and specifies the optional argument list for the
14230 given @var{COMMAND}.
14232 Upon reception, the message is processed and the corresponding command
14233 is injected into the filtergraph. Depending on the result, the filter
14234 will send a reply to the client, adopting the format:
14236 @var{ERROR_CODE} @var{ERROR_REASON}
14240 @var{MESSAGE} is optional.
14242 @subsection Examples
14244 Look at @file{tools/zmqsend} for an example of a zmq client which can
14245 be used to send commands processed by these filters.
14247 Consider the following filtergraph generated by @command{ffplay}
14249 ffplay -dumpgraph 1 -f lavfi "
14250 color=s=100x100:c=red [l];
14251 color=s=100x100:c=blue [r];
14252 nullsrc=s=200x100, zmq [bg];
14253 [bg][l] overlay [bg+l];
14254 [bg+l][r] overlay=x=100 "
14257 To change the color of the left side of the video, the following
14258 command can be used:
14260 echo Parsed_color_0 c yellow | tools/zmqsend
14263 To change the right side:
14265 echo Parsed_color_1 c pink | tools/zmqsend
14268 @c man end MULTIMEDIA FILTERS
14270 @chapter Multimedia Sources
14271 @c man begin MULTIMEDIA SOURCES
14273 Below is a description of the currently available multimedia sources.
14277 This is the same as @ref{movie} source, except it selects an audio
14283 Read audio and/or video stream(s) from a movie container.
14285 It accepts the following parameters:
14289 The name of the resource to read (not necessarily a file; it can also be a
14290 device or a stream accessed through some protocol).
14292 @item format_name, f
14293 Specifies the format assumed for the movie to read, and can be either
14294 the name of a container or an input device. If not specified, the
14295 format is guessed from @var{movie_name} or by probing.
14297 @item seek_point, sp
14298 Specifies the seek point in seconds. The frames will be output
14299 starting from this seek point. The parameter is evaluated with
14300 @code{av_strtod}, so the numerical value may be suffixed by an IS
14301 postfix. The default value is "0".
14304 Specifies the streams to read. Several streams can be specified,
14305 separated by "+". The source will then have as many outputs, in the
14306 same order. The syntax is explained in the ``Stream specifiers''
14307 section in the ffmpeg manual. Two special names, "dv" and "da" specify
14308 respectively the default (best suited) video and audio stream. Default
14309 is "dv", or "da" if the filter is called as "amovie".
14311 @item stream_index, si
14312 Specifies the index of the video stream to read. If the value is -1,
14313 the most suitable video stream will be automatically selected. The default
14314 value is "-1". Deprecated. If the filter is called "amovie", it will select
14315 audio instead of video.
14318 Specifies how many times to read the stream in sequence.
14319 If the value is less than 1, the stream will be read again and again.
14320 Default value is "1".
14322 Note that when the movie is looped the source timestamps are not
14323 changed, so it will generate non monotonically increasing timestamps.
14326 It allows overlaying a second video on top of the main input of
14327 a filtergraph, as shown in this graph:
14329 input -----------> deltapts0 --> overlay --> output
14332 movie --> scale--> deltapts1 -------+
14334 @subsection Examples
14338 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
14339 on top of the input labelled "in":
14341 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
14342 [in] setpts=PTS-STARTPTS [main];
14343 [main][over] overlay=16:16 [out]
14347 Read from a video4linux2 device, and overlay it on top of the input
14350 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
14351 [in] setpts=PTS-STARTPTS [main];
14352 [main][over] overlay=16:16 [out]
14356 Read the first video stream and the audio stream with id 0x81 from
14357 dvd.vob; the video is connected to the pad named "video" and the audio is
14358 connected to the pad named "audio":
14360 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
14364 @c man end MULTIMEDIA SOURCES