1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} functions defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of two forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows one to name a link and associate it to a filter output
176 or input pad. The preceding labels @var{in_link_1}
177 ... @var{in_link_N}, are associated to the filter input pads,
178 the following labels @var{out_link_1} ... @var{out_link_M}, are
179 associated to the output pads.
181 When two link labels with the same name are found in the
182 filtergraph, a link between the corresponding input and output pad is
185 If an output pad is not labelled, it is linked by default to the first
186 unlabelled input pad of the next filter in the filterchain.
187 For example in the filterchain
189 nullsrc, split[L1], [L2]overlay, nullsink
191 the split filter instance has two output pads, and the overlay filter
192 instance two input pads. The first output pad of split is labelled
193 "L1", the first input pad of overlay is labelled "L2", and the second
194 output pad of split is linked to the second input pad of overlay,
195 which are both unlabelled.
197 In a complete filterchain all the unlabelled filter input and output
198 pads must be connected. A filtergraph is considered valid if all the
199 filter input and output pads of all the filterchains are connected.
201 Libavfilter will automatically insert @ref{scale} filters where format
202 conversion is required. It is possible to specify swscale flags
203 for those automatically inserted scalers by prepending
204 @code{sws_flags=@var{flags};}
205 to the filtergraph description.
207 Here is a BNF description of the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
287 Additionally, these filters support an @option{enable} command that can be used
288 to re-define the expression.
290 Like any other filtering option, the @option{enable} option follows the same
293 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
294 minutes, and a @ref{curves} filter starting at 3 seconds:
296 smartblur = enable='between(t,10,3*60)',
297 curves = enable='gte(t,3)' : preset=cross_process
300 @c man end FILTERGRAPH DESCRIPTION
302 @chapter Audio Filters
303 @c man begin AUDIO FILTERS
305 When you configure your FFmpeg build, you can disable any of the
306 existing filters using @code{--disable-filters}.
307 The configure output will show the audio filters included in your
310 Below is a description of the currently available audio filters.
314 Convert the input audio format to the specified formats.
316 @emph{This filter is deprecated. Use @ref{aformat} instead.}
318 The filter accepts a string of the form:
319 "@var{sample_format}:@var{channel_layout}".
321 @var{sample_format} specifies the sample format, and can be a string or the
322 corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
323 suffix for a planar sample format.
325 @var{channel_layout} specifies the channel layout, and can be a string
326 or the corresponding number value defined in @file{libavutil/channel_layout.h}.
328 The special parameter "auto", signifies that the filter will
329 automatically select the output format depending on the output filter.
335 Convert input to float, planar, stereo:
341 Convert input to unsigned 8-bit, automatically select out channel layout:
349 Delay one or more audio channels.
351 Samples in delayed channel are filled with silence.
353 The filter accepts the following option:
357 Set list of delays in milliseconds for each channel separated by '|'.
358 At least one delay greater than 0 should be provided.
359 Unused delays will be silently ignored. If number of given delays is
360 smaller than number of channels all remaining channels will not be delayed.
367 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
368 the second channel (and any other channels that may be present) unchanged.
376 Apply echoing to the input audio.
378 Echoes are reflected sound and can occur naturally amongst mountains
379 (and sometimes large buildings) when talking or shouting; digital echo
380 effects emulate this behaviour and are often used to help fill out the
381 sound of a single instrument or vocal. The time difference between the
382 original signal and the reflection is the @code{delay}, and the
383 loudness of the reflected signal is the @code{decay}.
384 Multiple echoes can have different delays and decays.
386 A description of the accepted parameters follows.
390 Set input gain of reflected signal. Default is @code{0.6}.
393 Set output gain of reflected signal. Default is @code{0.3}.
396 Set list of time intervals in milliseconds between original signal and reflections
397 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
398 Default is @code{1000}.
401 Set list of loudnesses of reflected signals separated by '|'.
402 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
403 Default is @code{0.5}.
410 Make it sound as if there are twice as many instruments as are actually playing:
412 aecho=0.8:0.88:60:0.4
416 If delay is very short, then it sound like a (metallic) robot playing music:
422 A longer delay will sound like an open air concert in the mountains:
424 aecho=0.8:0.9:1000:0.3
428 Same as above but with one more mountain:
430 aecho=0.8:0.9:1000|1800:0.3|0.25
436 Modify an audio signal according to the specified expressions.
438 This filter accepts one or more expressions (one for each channel),
439 which are evaluated and used to modify a corresponding audio signal.
441 It accepts the following parameters:
445 Set the '|'-separated expressions list for each separate channel. If
446 the number of input channels is greater than the number of
447 expressions, the last specified expression is used for the remaining
450 @item channel_layout, c
451 Set output channel layout. If not specified, the channel layout is
452 specified by the number of expressions. If set to @samp{same}, it will
453 use by default the same input channel layout.
456 Each expression in @var{exprs} can contain the following constants and functions:
460 channel number of the current expression
463 number of the evaluated sample, starting from 0
469 time of the evaluated sample expressed in seconds
472 @item nb_out_channels
473 input and output number of channels
476 the value of input channel with number @var{CH}
479 Note: this filter is slow. For faster processing you should use a
488 aeval=val(ch)/2:c=same
492 Invert phase of the second channel:
500 Apply fade-in/out effect to input audio.
502 A description of the accepted parameters follows.
506 Specify the effect type, can be either @code{in} for fade-in, or
507 @code{out} for a fade-out effect. Default is @code{in}.
509 @item start_sample, ss
510 Specify the number of the start sample for starting to apply the fade
511 effect. Default is 0.
514 Specify the number of samples for which the fade effect has to last. At
515 the end of the fade-in effect the output audio will have the same
516 volume as the input audio, at the end of the fade-out transition
517 the output audio will be silence. Default is 44100.
520 Specify time for starting to apply the fade effect. Default is 0.
521 The accepted syntax is:
523 [-]HH[:MM[:SS[.m...]]]
526 See also the function @code{av_parse_time()}.
527 If set this option is used instead of @var{start_sample} one.
530 Specify the duration for which the fade effect has to last. Default is 0.
531 The accepted syntax is:
533 [-]HH[:MM[:SS[.m...]]]
536 See also the function @code{av_parse_time()}.
537 At the end of the fade-in effect the output audio will have the same
538 volume as the input audio, at the end of the fade-out transition
539 the output audio will be silence.
540 If set this option is used instead of @var{nb_samples} one.
543 Set curve for fade transition.
545 It accepts the following values:
548 select triangular, linear slope (default)
550 select quarter of sine wave
552 select half of sine wave
554 select exponential sine wave
558 select inverted parabola
574 Fade in first 15 seconds of audio:
580 Fade out last 25 seconds of a 900 seconds audio:
582 afade=t=out:st=875:d=25
589 Set output format constraints for the input audio. The framework will
590 negotiate the most appropriate format to minimize conversions.
592 It accepts the following parameters:
596 A '|'-separated list of requested sample formats.
599 A '|'-separated list of requested sample rates.
601 @item channel_layouts
602 A '|'-separated list of requested channel layouts.
604 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
605 for the required syntax.
608 If a parameter is omitted, all values are allowed.
610 Force the output to either unsigned 8-bit or signed 16-bit stereo
612 aformat=sample_fmts=u8|s16:channel_layouts=stereo
617 Apply a two-pole all-pass filter with central frequency (in Hz)
618 @var{frequency}, and filter-width @var{width}.
619 An all-pass filter changes the audio's frequency to phase relationship
620 without changing its frequency to amplitude relationship.
622 The filter accepts the following options:
629 Set method to specify band-width of filter.
642 Specify the band-width of a filter in width_type units.
647 Merge two or more audio streams into a single multi-channel stream.
649 The filter accepts the following options:
654 Set the number of inputs. Default is 2.
658 If the channel layouts of the inputs are disjoint, and therefore compatible,
659 the channel layout of the output will be set accordingly and the channels
660 will be reordered as necessary. If the channel layouts of the inputs are not
661 disjoint, the output will have all the channels of the first input then all
662 the channels of the second input, in that order, and the channel layout of
663 the output will be the default value corresponding to the total number of
666 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
667 is FC+BL+BR, then the output will be in 5.1, with the channels in the
668 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
669 first input, b1 is the first channel of the second input).
671 On the other hand, if both input are in stereo, the output channels will be
672 in the default order: a1, a2, b1, b2, and the channel layout will be
673 arbitrarily set to 4.0, which may or may not be the expected value.
675 All inputs must have the same sample rate, and format.
677 If inputs do not have the same duration, the output will stop with the
684 Merge two mono files into a stereo stream:
686 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
690 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
692 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
698 Mixes multiple audio inputs into a single output.
700 Note that this filter only supports float samples (the @var{amerge}
701 and @var{pan} audio filters support many formats). If the @var{amix}
702 input has integer samples then @ref{aresample} will be automatically
703 inserted to perform the conversion to float samples.
707 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
709 will mix 3 input audio streams to a single output with the same duration as the
710 first input and a dropout transition time of 3 seconds.
712 It accepts the following parameters:
716 The number of inputs. If unspecified, it defaults to 2.
719 How to determine the end-of-stream.
723 The duration of the longest input. (default)
726 The duration of the shortest input.
729 The duration of the first input.
733 @item dropout_transition
734 The transition time, in seconds, for volume renormalization when an input
735 stream ends. The default value is 2 seconds.
741 Pass the audio source unchanged to the output.
745 Pad the end of an audio stream with silence.
747 This can be used together with @command{ffmpeg} @option{-shortest} to
748 extend audio streams to the same length as the video stream.
750 A description of the accepted options follows.
754 Set silence packet size. Default value is 4096.
757 Set the number of samples of silence to add to the end. After the
758 value is reached, the stream is terminated. This option is mutually
759 exclusive with @option{whole_len}.
762 Set the minimum total number of samples in the output audio stream. If
763 the value is longer than the input audio length, silence is added to
764 the end, until the value is reached. This option is mutually exclusive
765 with @option{pad_len}.
768 If neither the @option{pad_len} nor the @option{whole_len} option is
769 set, the filter will add silence to the end of the input stream
776 Add 1024 samples of silence to the end of the input:
782 Make sure the audio output will contain at least 10000 samples, pad
783 the input with silence if required:
789 Use @command{ffmpeg} to pad the audio input with silence, so that the
790 video stream will always result the shortest and will be converted
791 until the end in the output file when using the @option{shortest}
794 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
799 Add a phasing effect to the input audio.
801 A phaser filter creates series of peaks and troughs in the frequency spectrum.
802 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
804 A description of the accepted parameters follows.
808 Set input gain. Default is 0.4.
811 Set output gain. Default is 0.74
814 Set delay in milliseconds. Default is 3.0.
817 Set decay. Default is 0.4.
820 Set modulation speed in Hz. Default is 0.5.
823 Set modulation type. Default is triangular.
825 It accepts the following values:
835 Resample the input audio to the specified parameters, using the
836 libswresample library. If none are specified then the filter will
837 automatically convert between its input and output.
839 This filter is also able to stretch/squeeze the audio data to make it match
840 the timestamps or to inject silence / cut out audio to make it match the
841 timestamps, do a combination of both or do neither.
843 The filter accepts the syntax
844 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
845 expresses a sample rate and @var{resampler_options} is a list of
846 @var{key}=@var{value} pairs, separated by ":". See the
847 ffmpeg-resampler manual for the complete list of supported options.
853 Resample the input audio to 44100Hz:
859 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
860 samples per second compensation:
866 @section asetnsamples
868 Set the number of samples per each output audio frame.
870 The last output packet may contain a different number of samples, as
871 the filter will flush all the remaining samples when the input audio
874 The filter accepts the following options:
878 @item nb_out_samples, n
879 Set the number of frames per each output audio frame. The number is
880 intended as the number of samples @emph{per each channel}.
881 Default value is 1024.
884 If set to 1, the filter will pad the last audio frame with zeroes, so
885 that the last frame will contain the same number of samples as the
886 previous ones. Default value is 1.
889 For example, to set the number of per-frame samples to 1234 and
890 disable padding for the last frame, use:
892 asetnsamples=n=1234:p=0
897 Set the sample rate without altering the PCM data.
898 This will result in a change of speed and pitch.
900 The filter accepts the following options:
904 Set the output sample rate. Default is 44100 Hz.
909 Show a line containing various information for each input audio frame.
910 The input audio is not modified.
912 The shown line contains a sequence of key/value pairs of the form
913 @var{key}:@var{value}.
915 The following values are shown in the output:
919 The (sequential) number of the input frame, starting from 0.
922 The presentation timestamp of the input frame, in time base units; the time base
923 depends on the filter input pad, and is usually 1/@var{sample_rate}.
926 The presentation timestamp of the input frame in seconds.
929 position of the frame in the input stream, -1 if this information in
930 unavailable and/or meaningless (for example in case of synthetic audio)
939 The sample rate for the audio frame.
942 The number of samples (per channel) in the frame.
945 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
946 audio, the data is treated as if all the planes were concatenated.
948 @item plane_checksums
949 A list of Adler-32 checksums for each data plane.
954 Display time domain statistical information about the audio channels.
955 Statistics are calculated and displayed for each audio channel and,
956 where applicable, an overall figure is also given.
958 It accepts the following option:
961 Short window length in seconds, used for peak and trough RMS measurement.
962 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
965 A description of each shown parameter follows:
969 Mean amplitude displacement from zero.
972 Minimal sample level.
975 Maximal sample level.
979 Standard peak and RMS level measured in dBFS.
983 Peak and trough values for RMS level measured over a short window.
986 Standard ratio of peak to RMS level (note: not in dB).
989 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
990 (i.e. either @var{Min level} or @var{Max level}).
993 Number of occasions (not the number of samples) that the signal attained either
994 @var{Min level} or @var{Max level}.
999 Forward two audio streams and control the order the buffers are forwarded.
1001 The filter accepts the following options:
1005 Set the expression deciding which stream should be
1006 forwarded next: if the result is negative, the first stream is forwarded; if
1007 the result is positive or zero, the second stream is forwarded. It can use
1008 the following variables:
1012 number of buffers forwarded so far on each stream
1014 number of samples forwarded so far on each stream
1016 current timestamp of each stream
1019 The default value is @code{t1-t2}, which means to always forward the stream
1020 that has a smaller timestamp.
1023 @subsection Examples
1025 Stress-test @code{amerge} by randomly sending buffers on the wrong
1026 input, while avoiding too much of a desynchronization:
1028 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
1029 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
1035 Synchronize audio data with timestamps by squeezing/stretching it and/or
1036 dropping samples/adding silence when needed.
1038 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1040 It accepts the following parameters:
1044 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1045 by default. When disabled, time gaps are covered with silence.
1048 The minimum difference between timestamps and audio data (in seconds) to trigger
1049 adding/dropping samples. The default value is 0.1. If you get an imperfect
1050 sync with this filter, try setting this parameter to 0.
1053 The maximum compensation in samples per second. Only relevant with compensate=1.
1054 The default value is 500.
1057 Assume that the first PTS should be this value. The time base is 1 / sample
1058 rate. This allows for padding/trimming at the start of the stream. By default,
1059 no assumption is made about the first frame's expected PTS, so no padding or
1060 trimming is done. For example, this could be set to 0 to pad the beginning with
1061 silence if an audio stream starts after the video stream or to trim any samples
1062 with a negative PTS due to encoder delay.
1070 The filter accepts exactly one parameter, the audio tempo. If not
1071 specified then the filter will assume nominal 1.0 tempo. Tempo must
1072 be in the [0.5, 2.0] range.
1074 @subsection Examples
1078 Slow down audio to 80% tempo:
1084 To speed up audio to 125% tempo:
1092 Trim the input so that the output contains one continuous subpart of the input.
1094 It accepts the following parameters:
1097 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1098 sample with the timestamp @var{start} will be the first sample in the output.
1101 Specify time of the first audio sample that will be dropped, i.e. the
1102 audio sample immediately preceding the one with the timestamp @var{end} will be
1103 the last sample in the output.
1106 Same as @var{start}, except this option sets the start timestamp in samples
1110 Same as @var{end}, except this option sets the end timestamp in samples instead
1114 The maximum duration of the output in seconds.
1117 The number of the first sample that should be output.
1120 The number of the first sample that should be dropped.
1123 @option{start}, @option{end}, @option{duration} are expressed as time
1124 duration specifications, check the "Time duration" section in the
1125 ffmpeg-utils manual.
1127 Note that the first two sets of the start/end options and the @option{duration}
1128 option look at the frame timestamp, while the _sample options simply count the
1129 samples that pass through the filter. So start/end_pts and start/end_sample will
1130 give different results when the timestamps are wrong, inexact or do not start at
1131 zero. Also note that this filter does not modify the timestamps. If you wish
1132 to have the output timestamps start at zero, insert the asetpts filter after the
1135 If multiple start or end options are set, this filter tries to be greedy and
1136 keep all samples that match at least one of the specified constraints. To keep
1137 only the part that matches all the constraints at once, chain multiple atrim
1140 The defaults are such that all the input is kept. So it is possible to set e.g.
1141 just the end values to keep everything before the specified time.
1146 Drop everything except the second minute of input:
1148 ffmpeg -i INPUT -af atrim=60:120
1152 Keep only the first 1000 samples:
1154 ffmpeg -i INPUT -af atrim=end_sample=1000
1161 Apply a two-pole Butterworth band-pass filter with central
1162 frequency @var{frequency}, and (3dB-point) band-width width.
1163 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1164 instead of the default: constant 0dB peak gain.
1165 The filter roll off at 6dB per octave (20dB per decade).
1167 The filter accepts the following options:
1171 Set the filter's central frequency. Default is @code{3000}.
1174 Constant skirt gain if set to 1. Defaults to 0.
1177 Set method to specify band-width of filter.
1190 Specify the band-width of a filter in width_type units.
1195 Apply a two-pole Butterworth band-reject filter with central
1196 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1197 The filter roll off at 6dB per octave (20dB per decade).
1199 The filter accepts the following options:
1203 Set the filter's central frequency. Default is @code{3000}.
1206 Set method to specify band-width of filter.
1219 Specify the band-width of a filter in width_type units.
1224 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1225 shelving filter with a response similar to that of a standard
1226 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1228 The filter accepts the following options:
1232 Give the gain at 0 Hz. Its useful range is about -20
1233 (for a large cut) to +20 (for a large boost).
1234 Beware of clipping when using a positive gain.
1237 Set the filter's central frequency and so can be used
1238 to extend or reduce the frequency range to be boosted or cut.
1239 The default value is @code{100} Hz.
1242 Set method to specify band-width of filter.
1255 Determine how steep is the filter's shelf transition.
1260 Apply a biquad IIR filter with the given coefficients.
1261 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1262 are the numerator and denominator coefficients respectively.
1265 Bauer stereo to binaural transformation, which improves headphone listening of
1266 stereo audio records.
1268 It accepts the following parameters:
1272 Pre-defined crossfeed level.
1276 Default level (fcut=700, feed=50).
1279 Chu Moy circuit (fcut=700, feed=60).
1282 Jan Meier circuit (fcut=650, feed=95).
1287 Cut frequency (in Hz).
1296 Remap input channels to new locations.
1298 It accepts the following parameters:
1300 @item channel_layout
1301 The channel layout of the output stream.
1304 Map channels from input to output. The argument is a '|'-separated list of
1305 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1306 @var{in_channel} form. @var{in_channel} can be either the name of the input
1307 channel (e.g. FL for front left) or its index in the input channel layout.
1308 @var{out_channel} is the name of the output channel or its index in the output
1309 channel layout. If @var{out_channel} is not given then it is implicitly an
1310 index, starting with zero and increasing by one for each mapping.
1313 If no mapping is present, the filter will implicitly map input channels to
1314 output channels, preserving indices.
1316 For example, assuming a 5.1+downmix input MOV file,
1318 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1320 will create an output WAV file tagged as stereo from the downmix channels of
1323 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1325 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1328 @section channelsplit
1330 Split each channel from an input audio stream into a separate output stream.
1332 It accepts the following parameters:
1334 @item channel_layout
1335 The channel layout of the input stream. The default is "stereo".
1338 For example, assuming a stereo input MP3 file,
1340 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1342 will create an output Matroska file with two audio streams, one containing only
1343 the left channel and the other the right channel.
1345 Split a 5.1 WAV file into per-channel files:
1347 ffmpeg -i in.wav -filter_complex
1348 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1349 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1350 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1355 Compress or expand the audio's dynamic range.
1357 It accepts the following parameters:
1363 A list of times in seconds for each channel over which the instantaneous level
1364 of the input signal is averaged to determine its volume. @var{attacks} refers to
1365 increase of volume and @var{decays} refers to decrease of volume. For most
1366 situations, the attack time (response to the audio getting louder) should be
1367 shorter than the decay time, because the human ear is more sensitive to sudden
1368 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1369 a typical value for decay is 0.8 seconds.
1372 A list of points for the transfer function, specified in dB relative to the
1373 maximum possible signal amplitude. Each key points list must be defined using
1374 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1375 @code{x0/y0 x1/y1 x2/y2 ....}
1377 The input values must be in strictly increasing order but the transfer function
1378 does not have to be monotonically rising. The point @code{0/0} is assumed but
1379 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1380 function are @code{-70/-70|-60/-20}.
1383 Set the curve radius in dB for all joints. It defaults to 0.01.
1386 Set the additional gain in dB to be applied at all points on the transfer
1387 function. This allows for easy adjustment of the overall gain.
1391 Set an initial volume, in dB, to be assumed for each channel when filtering
1392 starts. This permits the user to supply a nominal level initially, so that, for
1393 example, a very large gain is not applied to initial signal levels before the
1394 companding has begun to operate. A typical value for audio which is initially
1395 quiet is -90 dB. It defaults to 0.
1398 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1399 delayed before being fed to the volume adjuster. Specifying a delay
1400 approximately equal to the attack/decay times allows the filter to effectively
1401 operate in predictive rather than reactive mode. It defaults to 0.
1405 @subsection Examples
1409 Make music with both quiet and loud passages suitable for listening to in a
1412 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1416 A noise gate for when the noise is at a lower level than the signal:
1418 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1422 Here is another noise gate, this time for when the noise is at a higher level
1423 than the signal (making it, in some ways, similar to squelch):
1425 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1431 Make audio easier to listen to on headphones.
1433 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1434 so that when listened to on headphones the stereo image is moved from
1435 inside your head (standard for headphones) to outside and in front of
1436 the listener (standard for speakers).
1442 Apply a two-pole peaking equalisation (EQ) filter. With this
1443 filter, the signal-level at and around a selected frequency can
1444 be increased or decreased, whilst (unlike bandpass and bandreject
1445 filters) that at all other frequencies is unchanged.
1447 In order to produce complex equalisation curves, this filter can
1448 be given several times, each with a different central frequency.
1450 The filter accepts the following options:
1454 Set the filter's central frequency in Hz.
1457 Set method to specify band-width of filter.
1470 Specify the band-width of a filter in width_type units.
1473 Set the required gain or attenuation in dB.
1474 Beware of clipping when using a positive gain.
1477 @subsection Examples
1480 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1482 equalizer=f=1000:width_type=h:width=200:g=-10
1486 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1488 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1493 Apply a flanging effect to the audio.
1495 The filter accepts the following options:
1499 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1502 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1505 Set percentage regeneneration (delayed signal feedback). Range from -95 to 95.
1509 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1513 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1516 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1517 Default value is @var{sinusoidal}.
1520 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1521 Default value is 25.
1524 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1525 Default is @var{linear}.
1530 Apply a high-pass filter with 3dB point frequency.
1531 The filter can be either single-pole, or double-pole (the default).
1532 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1534 The filter accepts the following options:
1538 Set frequency in Hz. Default is 3000.
1541 Set number of poles. Default is 2.
1544 Set method to specify band-width of filter.
1557 Specify the band-width of a filter in width_type units.
1558 Applies only to double-pole filter.
1559 The default is 0.707q and gives a Butterworth response.
1564 Join multiple input streams into one multi-channel stream.
1566 It accepts the following parameters:
1570 The number of input streams. It defaults to 2.
1572 @item channel_layout
1573 The desired output channel layout. It defaults to stereo.
1576 Map channels from inputs to output. The argument is a '|'-separated list of
1577 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1578 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1579 can be either the name of the input channel (e.g. FL for front left) or its
1580 index in the specified input stream. @var{out_channel} is the name of the output
1584 The filter will attempt to guess the mappings when they are not specified
1585 explicitly. It does so by first trying to find an unused matching input channel
1586 and if that fails it picks the first unused input channel.
1588 Join 3 inputs (with properly set channel layouts):
1590 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1593 Build a 5.1 output from 6 single-channel streams:
1595 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1596 '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'
1602 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1604 To enable compilation of this filter you need to configure FFmpeg with
1605 @code{--enable-ladspa}.
1609 Specifies the name of LADSPA plugin library to load. If the environment
1610 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1611 each one of the directories specified by the colon separated list in
1612 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1613 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1614 @file{/usr/lib/ladspa/}.
1617 Specifies the plugin within the library. Some libraries contain only
1618 one plugin, but others contain many of them. If this is not set filter
1619 will list all available plugins within the specified library.
1622 Set the '|' separated list of controls which are zero or more floating point
1623 values that determine the behavior of the loaded plugin (for example delay,
1625 Controls need to be defined using the following syntax:
1626 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1627 @var{valuei} is the value set on the @var{i}-th control.
1628 If @option{controls} is set to @code{help}, all available controls and
1629 their valid ranges are printed.
1631 @item sample_rate, s
1632 Specify the sample rate, default to 44100. Only used if plugin have
1636 Set the number of samples per channel per each output frame, default
1637 is 1024. Only used if plugin have zero inputs.
1640 Set the minimum duration of the sourced audio. See the function
1641 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1642 section in the ffmpeg-utils manual.
1643 Note that the resulting duration may be greater than the specified duration,
1644 as the generated audio is always cut at the end of a complete frame.
1645 If not specified, or the expressed duration is negative, the audio is
1646 supposed to be generated forever.
1647 Only used if plugin have zero inputs.
1651 @subsection Examples
1655 List all available plugins within amp (LADSPA example plugin) library:
1661 List all available controls and their valid ranges for @code{vcf_notch}
1662 plugin from @code{VCF} library:
1664 ladspa=f=vcf:p=vcf_notch:c=help
1668 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1671 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1675 Add reverberation to the audio using TAP-plugins
1676 (Tom's Audio Processing plugins):
1678 ladspa=file=tap_reverb:tap_reverb
1682 Generate white noise, with 0.2 amplitude:
1684 ladspa=file=cmt:noise_source_white:c=c0=.2
1688 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1689 @code{C* Audio Plugin Suite} (CAPS) library:
1691 ladspa=file=caps:Click:c=c1=20'
1695 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1697 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1701 @subsection Commands
1703 This filter supports the following commands:
1706 Modify the @var{N}-th control value.
1708 If the specified value is not valid, it is ignored and prior one is kept.
1713 Apply a low-pass filter with 3dB point frequency.
1714 The filter can be either single-pole or double-pole (the default).
1715 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1717 The filter accepts the following options:
1721 Set frequency in Hz. Default is 500.
1724 Set number of poles. Default is 2.
1727 Set method to specify band-width of filter.
1740 Specify the band-width of a filter in width_type units.
1741 Applies only to double-pole filter.
1742 The default is 0.707q and gives a Butterworth response.
1747 Mix channels with specific gain levels. The filter accepts the output
1748 channel layout followed by a set of channels definitions.
1750 This filter is also designed to remap efficiently the channels of an audio
1753 The filter accepts parameters of the form:
1754 "@var{l}:@var{outdef}:@var{outdef}:..."
1758 output channel layout or number of channels
1761 output channel specification, of the form:
1762 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1765 output channel to define, either a channel name (FL, FR, etc.) or a channel
1766 number (c0, c1, etc.)
1769 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1772 input channel to use, see out_name for details; it is not possible to mix
1773 named and numbered input channels
1776 If the `=' in a channel specification is replaced by `<', then the gains for
1777 that specification will be renormalized so that the total is 1, thus
1778 avoiding clipping noise.
1780 @subsection Mixing examples
1782 For example, if you want to down-mix from stereo to mono, but with a bigger
1783 factor for the left channel:
1785 pan=1:c0=0.9*c0+0.1*c1
1788 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1789 7-channels surround:
1791 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1794 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1795 that should be preferred (see "-ac" option) unless you have very specific
1798 @subsection Remapping examples
1800 The channel remapping will be effective if, and only if:
1803 @item gain coefficients are zeroes or ones,
1804 @item only one input per channel output,
1807 If all these conditions are satisfied, the filter will notify the user ("Pure
1808 channel mapping detected"), and use an optimized and lossless method to do the
1811 For example, if you have a 5.1 source and want a stereo audio stream by
1812 dropping the extra channels:
1814 pan="stereo: c0=FL : c1=FR"
1817 Given the same source, you can also switch front left and front right channels
1818 and keep the input channel layout:
1820 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1823 If the input is a stereo audio stream, you can mute the front left channel (and
1824 still keep the stereo channel layout) with:
1829 Still with a stereo audio stream input, you can copy the right channel in both
1830 front left and right:
1832 pan="stereo: c0=FR : c1=FR"
1837 ReplayGain scanner filter. This filter takes an audio stream as an input and
1838 outputs it unchanged.
1839 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1843 Convert the audio sample format, sample rate and channel layout. It is
1844 not meant to be used directly.
1846 @section silencedetect
1848 Detect silence in an audio stream.
1850 This filter logs a message when it detects that the input audio volume is less
1851 or equal to a noise tolerance value for a duration greater or equal to the
1852 minimum detected noise duration.
1854 The printed times and duration are expressed in seconds.
1856 The filter accepts the following options:
1860 Set silence duration until notification (default is 2 seconds).
1863 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1864 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1867 @subsection Examples
1871 Detect 5 seconds of silence with -50dB noise tolerance:
1873 silencedetect=n=-50dB:d=5
1877 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1878 tolerance in @file{silence.mp3}:
1880 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1886 Boost or cut treble (upper) frequencies of the audio using a two-pole
1887 shelving filter with a response similar to that of a standard
1888 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1890 The filter accepts the following options:
1894 Give the gain at whichever is the lower of ~22 kHz and the
1895 Nyquist frequency. Its useful range is about -20 (for a large cut)
1896 to +20 (for a large boost). Beware of clipping when using a positive gain.
1899 Set the filter's central frequency and so can be used
1900 to extend or reduce the frequency range to be boosted or cut.
1901 The default value is @code{3000} Hz.
1904 Set method to specify band-width of filter.
1917 Determine how steep is the filter's shelf transition.
1922 Adjust the input audio volume.
1924 It accepts the following parameters:
1928 Set audio volume expression.
1930 Output values are clipped to the maximum value.
1932 The output audio volume is given by the relation:
1934 @var{output_volume} = @var{volume} * @var{input_volume}
1937 The default value for @var{volume} is "1.0".
1940 This parameter represents the mathematical precision.
1942 It determines which input sample formats will be allowed, which affects the
1943 precision of the volume scaling.
1947 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1949 32-bit floating-point; this limits input sample format to FLT. (default)
1951 64-bit floating-point; this limits input sample format to DBL.
1955 Choose the behaviour on encountering ReplayGain side data in input frames.
1959 Remove ReplayGain side data, ignoring its contents (the default).
1962 Ignore ReplayGain side data, but leave it in the frame.
1965 Prefer the track gain, if present.
1968 Prefer the album gain, if present.
1971 @item replaygain_preamp
1972 Pre-amplification gain in dB to apply to the selected replaygain gain.
1974 Default value for @var{replaygain_preamp} is 0.0.
1977 Set when the volume expression is evaluated.
1979 It accepts the following values:
1982 only evaluate expression once during the filter initialization, or
1983 when the @samp{volume} command is sent
1986 evaluate expression for each incoming frame
1989 Default value is @samp{once}.
1992 The volume expression can contain the following parameters.
1996 frame number (starting at zero)
1999 @item nb_consumed_samples
2000 number of samples consumed by the filter
2002 number of samples in the current frame
2004 original frame position in the file
2010 PTS at start of stream
2012 time at start of stream
2018 last set volume value
2021 Note that when @option{eval} is set to @samp{once} only the
2022 @var{sample_rate} and @var{tb} variables are available, all other
2023 variables will evaluate to NAN.
2025 @subsection Commands
2027 This filter supports the following commands:
2030 Modify the volume expression.
2031 The command accepts the same syntax of the corresponding option.
2033 If the specified expression is not valid, it is kept at its current
2035 @item replaygain_noclip
2036 Prevent clipping by limiting the gain applied.
2038 Default value for @var{replaygain_noclip} is 1.
2042 @subsection Examples
2046 Halve the input audio volume:
2050 volume=volume=-6.0206dB
2053 In all the above example the named key for @option{volume} can be
2054 omitted, for example like in:
2060 Increase input audio power by 6 decibels using fixed-point precision:
2062 volume=volume=6dB:precision=fixed
2066 Fade volume after time 10 with an annihilation period of 5 seconds:
2068 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2072 @section volumedetect
2074 Detect the volume of the input video.
2076 The filter has no parameters. The input is not modified. Statistics about
2077 the volume will be printed in the log when the input stream end is reached.
2079 In particular it will show the mean volume (root mean square), maximum
2080 volume (on a per-sample basis), and the beginning of a histogram of the
2081 registered volume values (from the maximum value to a cumulated 1/1000 of
2084 All volumes are in decibels relative to the maximum PCM value.
2086 @subsection Examples
2088 Here is an excerpt of the output:
2090 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2091 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2092 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2093 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2094 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2095 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2096 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2097 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2098 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2104 The mean square energy is approximately -27 dB, or 10^-2.7.
2106 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2108 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2111 In other words, raising the volume by +4 dB does not cause any clipping,
2112 raising it by +5 dB causes clipping for 6 samples, etc.
2114 @c man end AUDIO FILTERS
2116 @chapter Audio Sources
2117 @c man begin AUDIO SOURCES
2119 Below is a description of the currently available audio sources.
2123 Buffer audio frames, and make them available to the filter chain.
2125 This source is mainly intended for a programmatic use, in particular
2126 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2128 It accepts the following parameters:
2132 The timebase which will be used for timestamps of submitted frames. It must be
2133 either a floating-point number or in @var{numerator}/@var{denominator} form.
2136 The sample rate of the incoming audio buffers.
2139 The sample format of the incoming audio buffers.
2140 Either a sample format name or its corresponging integer representation from
2141 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2143 @item channel_layout
2144 The channel layout of the incoming audio buffers.
2145 Either a channel layout name from channel_layout_map in
2146 @file{libavutil/channel_layout.c} or its corresponding integer representation
2147 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2150 The number of channels of the incoming audio buffers.
2151 If both @var{channels} and @var{channel_layout} are specified, then they
2156 @subsection Examples
2159 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2162 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2163 Since the sample format with name "s16p" corresponds to the number
2164 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2167 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2172 Generate an audio signal specified by an expression.
2174 This source accepts in input one or more expressions (one for each
2175 channel), which are evaluated and used to generate a corresponding
2178 This source accepts the following options:
2182 Set the '|'-separated expressions list for each separate channel. In case the
2183 @option{channel_layout} option is not specified, the selected channel layout
2184 depends on the number of provided expressions. Otherwise the last
2185 specified expression is applied to the remaining output channels.
2187 @item channel_layout, c
2188 Set the channel layout. The number of channels in the specified layout
2189 must be equal to the number of specified expressions.
2192 Set the minimum duration of the sourced audio. See the function
2193 @code{av_parse_time()} for the accepted format.
2194 Note that the resulting duration may be greater than the specified
2195 duration, as the generated audio is always cut at the end of a
2198 If not specified, or the expressed duration is negative, the audio is
2199 supposed to be generated forever.
2202 Set the number of samples per channel per each output frame,
2205 @item sample_rate, s
2206 Specify the sample rate, default to 44100.
2209 Each expression in @var{exprs} can contain the following constants:
2213 number of the evaluated sample, starting from 0
2216 time of the evaluated sample expressed in seconds, starting from 0
2223 @subsection Examples
2233 Generate a sin signal with frequency of 440 Hz, set sample rate to
2236 aevalsrc="sin(440*2*PI*t):s=8000"
2240 Generate a two channels signal, specify the channel layout (Front
2241 Center + Back Center) explicitly:
2243 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2247 Generate white noise:
2249 aevalsrc="-2+random(0)"
2253 Generate an amplitude modulated signal:
2255 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2259 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2261 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2268 The null audio source, return unprocessed audio frames. It is mainly useful
2269 as a template and to be employed in analysis / debugging tools, or as
2270 the source for filters which ignore the input data (for example the sox
2273 This source accepts the following options:
2277 @item channel_layout, cl
2279 Specifies the channel layout, and can be either an integer or a string
2280 representing a channel layout. The default value of @var{channel_layout}
2283 Check the channel_layout_map definition in
2284 @file{libavutil/channel_layout.c} for the mapping between strings and
2285 channel layout values.
2287 @item sample_rate, r
2288 Specifies the sample rate, and defaults to 44100.
2291 Set the number of samples per requested frames.
2295 @subsection Examples
2299 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2301 anullsrc=r=48000:cl=4
2305 Do the same operation with a more obvious syntax:
2307 anullsrc=r=48000:cl=mono
2311 All the parameters need to be explicitly defined.
2315 Synthesize a voice utterance using the libflite library.
2317 To enable compilation of this filter you need to configure FFmpeg with
2318 @code{--enable-libflite}.
2320 Note that the flite library is not thread-safe.
2322 The filter accepts the following options:
2327 If set to 1, list the names of the available voices and exit
2328 immediately. Default value is 0.
2331 Set the maximum number of samples per frame. Default value is 512.
2334 Set the filename containing the text to speak.
2337 Set the text to speak.
2340 Set the voice to use for the speech synthesis. Default value is
2341 @code{kal}. See also the @var{list_voices} option.
2344 @subsection Examples
2348 Read from file @file{speech.txt}, and synthetize the text using the
2349 standard flite voice:
2351 flite=textfile=speech.txt
2355 Read the specified text selecting the @code{slt} voice:
2357 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2361 Input text to ffmpeg:
2363 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2367 Make @file{ffplay} speak the specified text, using @code{flite} and
2368 the @code{lavfi} device:
2370 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2374 For more information about libflite, check:
2375 @url{http://www.speech.cs.cmu.edu/flite/}
2379 Generate an audio signal made of a sine wave with amplitude 1/8.
2381 The audio signal is bit-exact.
2383 The filter accepts the following options:
2388 Set the carrier frequency. Default is 440 Hz.
2390 @item beep_factor, b
2391 Enable a periodic beep every second with frequency @var{beep_factor} times
2392 the carrier frequency. Default is 0, meaning the beep is disabled.
2394 @item sample_rate, r
2395 Specify the sample rate, default is 44100.
2398 Specify the duration of the generated audio stream.
2400 @item samples_per_frame
2401 Set the number of samples per output frame, default is 1024.
2404 @subsection Examples
2409 Generate a simple 440 Hz sine wave:
2415 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2419 sine=frequency=220:beep_factor=4:duration=5
2424 @c man end AUDIO SOURCES
2426 @chapter Audio Sinks
2427 @c man begin AUDIO SINKS
2429 Below is a description of the currently available audio sinks.
2431 @section abuffersink
2433 Buffer audio frames, and make them available to the end of filter chain.
2435 This sink is mainly intended for programmatic use, in particular
2436 through the interface defined in @file{libavfilter/buffersink.h}
2437 or the options system.
2439 It accepts a pointer to an AVABufferSinkContext structure, which
2440 defines the incoming buffers' formats, to be passed as the opaque
2441 parameter to @code{avfilter_init_filter} for initialization.
2444 Null audio sink; do absolutely nothing with the input audio. It is
2445 mainly useful as a template and for use in analysis / debugging
2448 @c man end AUDIO SINKS
2450 @chapter Video Filters
2451 @c man begin VIDEO FILTERS
2453 When you configure your FFmpeg build, you can disable any of the
2454 existing filters using @code{--disable-filters}.
2455 The configure output will show the video filters included in your
2458 Below is a description of the currently available video filters.
2460 @section alphaextract
2462 Extract the alpha component from the input as a grayscale video. This
2463 is especially useful with the @var{alphamerge} filter.
2467 Add or replace the alpha component of the primary input with the
2468 grayscale value of a second input. This is intended for use with
2469 @var{alphaextract} to allow the transmission or storage of frame
2470 sequences that have alpha in a format that doesn't support an alpha
2473 For example, to reconstruct full frames from a normal YUV-encoded video
2474 and a separate video created with @var{alphaextract}, you might use:
2476 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2479 Since this filter is designed for reconstruction, it operates on frame
2480 sequences without considering timestamps, and terminates when either
2481 input reaches end of stream. This will cause problems if your encoding
2482 pipeline drops frames. If you're trying to apply an image as an
2483 overlay to a video stream, consider the @var{overlay} filter instead.
2487 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2488 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2489 Substation Alpha) subtitles files.
2493 Compute the bounding box for the non-black pixels in the input frame
2496 This filter computes the bounding box containing all the pixels with a
2497 luminance value greater than the minimum allowed value.
2498 The parameters describing the bounding box are printed on the filter
2501 The filter accepts the following option:
2505 Set the minimal luminance value. Default is @code{16}.
2508 @section blackdetect
2510 Detect video intervals that are (almost) completely black. Can be
2511 useful to detect chapter transitions, commercials, or invalid
2512 recordings. Output lines contains the time for the start, end and
2513 duration of the detected black interval expressed in seconds.
2515 In order to display the output lines, you need to set the loglevel at
2516 least to the AV_LOG_INFO value.
2518 The filter accepts the following options:
2521 @item black_min_duration, d
2522 Set the minimum detected black duration expressed in seconds. It must
2523 be a non-negative floating point number.
2525 Default value is 2.0.
2527 @item picture_black_ratio_th, pic_th
2528 Set the threshold for considering a picture "black".
2529 Express the minimum value for the ratio:
2531 @var{nb_black_pixels} / @var{nb_pixels}
2534 for which a picture is considered black.
2535 Default value is 0.98.
2537 @item pixel_black_th, pix_th
2538 Set the threshold for considering a pixel "black".
2540 The threshold expresses the maximum pixel luminance value for which a
2541 pixel is considered "black". The provided value is scaled according to
2542 the following equation:
2544 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2547 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2548 the input video format, the range is [0-255] for YUV full-range
2549 formats and [16-235] for YUV non full-range formats.
2551 Default value is 0.10.
2554 The following example sets the maximum pixel threshold to the minimum
2555 value, and detects only black intervals of 2 or more seconds:
2557 blackdetect=d=2:pix_th=0.00
2562 Detect frames that are (almost) completely black. Can be useful to
2563 detect chapter transitions or commercials. Output lines consist of
2564 the frame number of the detected frame, the percentage of blackness,
2565 the position in the file if known or -1 and the timestamp in seconds.
2567 In order to display the output lines, you need to set the loglevel at
2568 least to the AV_LOG_INFO value.
2570 It accepts the following parameters:
2575 The percentage of the pixels that have to be below the threshold; it defaults to
2578 @item threshold, thresh
2579 The threshold below which a pixel value is considered black; it defaults to
2586 Blend two video frames into each other.
2588 It takes two input streams and outputs one stream, the first input is the
2589 "top" layer and second input is "bottom" layer.
2590 Output terminates when shortest input terminates.
2592 A description of the accepted options follows.
2600 Set blend mode for specific pixel component or all pixel components in case
2601 of @var{all_mode}. Default value is @code{normal}.
2603 Available values for component modes are:
2636 Set blend opacity for specific pixel component or all pixel components in case
2637 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2644 Set blend expression for specific pixel component or all pixel components in case
2645 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2647 The expressions can use the following variables:
2651 The sequential number of the filtered frame, starting from @code{0}.
2655 the coordinates of the current sample
2659 the width and height of currently filtered plane
2663 Width and height scale depending on the currently filtered plane. It is the
2664 ratio between the corresponding luma plane number of pixels and the current
2665 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2666 @code{0.5,0.5} for chroma planes.
2669 Time of the current frame, expressed in seconds.
2672 Value of pixel component at current location for first video frame (top layer).
2675 Value of pixel component at current location for second video frame (bottom layer).
2679 Force termination when the shortest input terminates. Default is @code{0}.
2681 Continue applying the last bottom frame after the end of the stream. A value of
2682 @code{0} disable the filter after the last frame of the bottom layer is reached.
2683 Default is @code{1}.
2686 @subsection Examples
2690 Apply transition from bottom layer to top layer in first 10 seconds:
2692 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2696 Apply 1x1 checkerboard effect:
2698 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2702 Apply uncover left effect:
2704 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2708 Apply uncover down effect:
2710 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2714 Apply uncover up-left effect:
2716 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2722 Apply a boxblur algorithm to the input video.
2724 It accepts the following parameters:
2728 @item luma_radius, lr
2729 @item luma_power, lp
2730 @item chroma_radius, cr
2731 @item chroma_power, cp
2732 @item alpha_radius, ar
2733 @item alpha_power, ap
2737 A description of the accepted options follows.
2740 @item luma_radius, lr
2741 @item chroma_radius, cr
2742 @item alpha_radius, ar
2743 Set an expression for the box radius in pixels used for blurring the
2744 corresponding input plane.
2746 The radius value must be a non-negative number, and must not be
2747 greater than the value of the expression @code{min(w,h)/2} for the
2748 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2751 Default value for @option{luma_radius} is "2". If not specified,
2752 @option{chroma_radius} and @option{alpha_radius} default to the
2753 corresponding value set for @option{luma_radius}.
2755 The expressions can contain the following constants:
2759 The input width and height in pixels.
2763 The input chroma image width and height in pixels.
2767 The horizontal and vertical chroma subsample values. For example, for the
2768 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2771 @item luma_power, lp
2772 @item chroma_power, cp
2773 @item alpha_power, ap
2774 Specify how many times the boxblur filter is applied to the
2775 corresponding plane.
2777 Default value for @option{luma_power} is 2. If not specified,
2778 @option{chroma_power} and @option{alpha_power} default to the
2779 corresponding value set for @option{luma_power}.
2781 A value of 0 will disable the effect.
2784 @subsection Examples
2788 Apply a boxblur filter with the luma, chroma, and alpha radii
2791 boxblur=luma_radius=2:luma_power=1
2796 Set the luma radius to 2, and alpha and chroma radius to 0:
2798 boxblur=2:1:cr=0:ar=0
2802 Set the luma and chroma radii to a fraction of the video dimension:
2804 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2810 Visualize information exported by some codecs.
2812 Some codecs can export information through frames using side-data or other
2813 means. For example, some MPEG based codecs export motion vectors through the
2814 @var{export_mvs} flag in the codec @option{flags2} option.
2816 The filter accepts the following option:
2820 Set motion vectors to visualize.
2822 Available flags for @var{mv} are:
2826 forward predicted MVs of P-frames
2828 forward predicted MVs of B-frames
2830 backward predicted MVs of B-frames
2834 @subsection Examples
2838 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
2840 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
2844 @section colorbalance
2845 Modify intensity of primary colors (red, green and blue) of input frames.
2847 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2848 regions for the red-cyan, green-magenta or blue-yellow balance.
2850 A positive adjustment value shifts the balance towards the primary color, a negative
2851 value towards the complementary color.
2853 The filter accepts the following options:
2859 Adjust red, green and blue shadows (darkest pixels).
2864 Adjust red, green and blue midtones (medium pixels).
2869 Adjust red, green and blue highlights (brightest pixels).
2871 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2874 @subsection Examples
2878 Add red color cast to shadows:
2884 @section colorchannelmixer
2886 Adjust video input frames by re-mixing color channels.
2888 This filter modifies a color channel by adding the values associated to
2889 the other channels of the same pixels. For example if the value to
2890 modify is red, the output value will be:
2892 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2895 The filter accepts the following options:
2902 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2903 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2909 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2910 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2916 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2917 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2923 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2924 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2926 Allowed ranges for options are @code{[-2.0, 2.0]}.
2929 @subsection Examples
2933 Convert source to grayscale:
2935 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2938 Simulate sepia tones:
2940 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2944 @section colormatrix
2946 Convert color matrix.
2948 The filter accepts the following options:
2953 Specify the source and destination color matrix. Both values must be
2956 The accepted values are:
2972 For example to convert from BT.601 to SMPTE-240M, use the command:
2974 colormatrix=bt601:smpte240m
2979 Copy the input source unchanged to the output. This is mainly useful for
2984 Crop the input video to given dimensions.
2986 It accepts the following parameters:
2990 The width of the output video. It defaults to @code{iw}.
2991 This expression is evaluated only once during the filter
2995 The height of the output video. It defaults to @code{ih}.
2996 This expression is evaluated only once during the filter
3000 The horizontal position, in the input video, of the left edge of the output
3001 video. It defaults to @code{(in_w-out_w)/2}.
3002 This expression is evaluated per-frame.
3005 The vertical position, in the input video, of the top edge of the output video.
3006 It defaults to @code{(in_h-out_h)/2}.
3007 This expression is evaluated per-frame.
3010 If set to 1 will force the output display aspect ratio
3011 to be the same of the input, by changing the output sample aspect
3012 ratio. It defaults to 0.
3015 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3016 expressions containing the following constants:
3021 The computed values for @var{x} and @var{y}. They are evaluated for
3026 The input width and height.
3030 These are the same as @var{in_w} and @var{in_h}.
3034 The output (cropped) width and height.
3038 These are the same as @var{out_w} and @var{out_h}.
3041 same as @var{iw} / @var{ih}
3044 input sample aspect ratio
3047 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3051 horizontal and vertical chroma subsample values. For example for the
3052 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3055 The number of the input frame, starting from 0.
3058 the position in the file of the input frame, NAN if unknown
3061 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3065 The expression for @var{out_w} may depend on the value of @var{out_h},
3066 and the expression for @var{out_h} may depend on @var{out_w}, but they
3067 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3068 evaluated after @var{out_w} and @var{out_h}.
3070 The @var{x} and @var{y} parameters specify the expressions for the
3071 position of the top-left corner of the output (non-cropped) area. They
3072 are evaluated for each frame. If the evaluated value is not valid, it
3073 is approximated to the nearest valid value.
3075 The expression for @var{x} may depend on @var{y}, and the expression
3076 for @var{y} may depend on @var{x}.
3078 @subsection Examples
3082 Crop area with size 100x100 at position (12,34).
3087 Using named options, the example above becomes:
3089 crop=w=100:h=100:x=12:y=34
3093 Crop the central input area with size 100x100:
3099 Crop the central input area with size 2/3 of the input video:
3101 crop=2/3*in_w:2/3*in_h
3105 Crop the input video central square:
3112 Delimit the rectangle with the top-left corner placed at position
3113 100:100 and the right-bottom corner corresponding to the right-bottom
3114 corner of the input image.
3116 crop=in_w-100:in_h-100:100:100
3120 Crop 10 pixels from the left and right borders, and 20 pixels from
3121 the top and bottom borders
3123 crop=in_w-2*10:in_h-2*20
3127 Keep only the bottom right quarter of the input image:
3129 crop=in_w/2:in_h/2:in_w/2:in_h/2
3133 Crop height for getting Greek harmony:
3135 crop=in_w:1/PHI*in_w
3139 Appply trembling effect:
3141 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)
3145 Apply erratic camera effect depending on timestamp:
3147 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)"
3151 Set x depending on the value of y:
3153 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3159 Auto-detect the crop size.
3161 It calculates the necessary cropping parameters and prints the
3162 recommended parameters via the logging system. The detected dimensions
3163 correspond to the non-black area of the input video.
3165 It accepts the following parameters:
3170 Set higher black value threshold, which can be optionally specified
3171 from nothing (0) to everything (255). An intensity value greater
3172 to the set value is considered non-black. It defaults to 24.
3175 The value which the width/height should be divisible by. It defaults to
3176 16. The offset is automatically adjusted to center the video. Use 2 to
3177 get only even dimensions (needed for 4:2:2 video). 16 is best when
3178 encoding to most video codecs.
3180 @item reset_count, reset
3181 Set the counter that determines after how many frames cropdetect will
3182 reset the previously detected largest video area and start over to
3183 detect the current optimal crop area. Default value is 0.
3185 This can be useful when channel logos distort the video area. 0
3186 indicates 'never reset', and returns the largest area encountered during
3193 Apply color adjustments using curves.
3195 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3196 component (red, green and blue) has its values defined by @var{N} key points
3197 tied from each other using a smooth curve. The x-axis represents the pixel
3198 values from the input frame, and the y-axis the new pixel values to be set for
3201 By default, a component curve is defined by the two points @var{(0;0)} and
3202 @var{(1;1)}. This creates a straight line where each original pixel value is
3203 "adjusted" to its own value, which means no change to the image.
3205 The filter allows you to redefine these two points and add some more. A new
3206 curve (using a natural cubic spline interpolation) will be define to pass
3207 smoothly through all these new coordinates. The new defined points needs to be
3208 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3209 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3210 the vector spaces, the values will be clipped accordingly.
3212 If there is no key point defined in @code{x=0}, the filter will automatically
3213 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3214 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3216 The filter accepts the following options:
3220 Select one of the available color presets. This option can be used in addition
3221 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3222 options takes priority on the preset values.
3223 Available presets are:
3226 @item color_negative
3229 @item increase_contrast
3231 @item linear_contrast
3232 @item medium_contrast
3234 @item strong_contrast
3237 Default is @code{none}.
3239 Set the master key points. These points will define a second pass mapping. It
3240 is sometimes called a "luminance" or "value" mapping. It can be used with
3241 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3242 post-processing LUT.
3244 Set the key points for the red component.
3246 Set the key points for the green component.
3248 Set the key points for the blue component.
3250 Set the key points for all components (not including master).
3251 Can be used in addition to the other key points component
3252 options. In this case, the unset component(s) will fallback on this
3253 @option{all} setting.
3255 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3258 To avoid some filtergraph syntax conflicts, each key points list need to be
3259 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3261 @subsection Examples
3265 Increase slightly the middle level of blue:
3267 curves=blue='0.5/0.58'
3273 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3275 Here we obtain the following coordinates for each components:
3278 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3280 @code{(0;0) (0.50;0.48) (1;1)}
3282 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3286 The previous example can also be achieved with the associated built-in preset:
3288 curves=preset=vintage
3298 Use a Photoshop preset and redefine the points of the green component:
3300 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3306 Denoise frames using 2D DCT (frequency domain filtering).
3308 This filter is not designed for real time.
3310 The filter accepts the following options:
3314 Set the noise sigma constant.
3316 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3317 coefficient (absolute value) below this threshold with be dropped.
3319 If you need a more advanced filtering, see @option{expr}.
3321 Default is @code{0}.
3324 Set number overlapping pixels for each block. Since the filter can be slow, you
3325 may want to reduce this value, at the cost of a less effective filter and the
3326 risk of various artefacts.
3328 If the overlapping value doesn't allow to process the whole input width or
3329 height, a warning will be displayed and according borders won't be denoised.
3331 Default value is @var{blocksize}-1, which is the best possible setting.
3334 Set the coefficient factor expression.
3336 For each coefficient of a DCT block, this expression will be evaluated as a
3337 multiplier value for the coefficient.
3339 If this is option is set, the @option{sigma} option will be ignored.
3341 The absolute value of the coefficient can be accessed through the @var{c}
3345 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3346 @var{blocksize}, which is the width and height of the processed blocks.
3348 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3349 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3350 on the speed processing. Also, a larger block size does not necessarily means a
3354 @subsection Examples
3356 Apply a denoise with a @option{sigma} of @code{4.5}:
3361 The same operation can be achieved using the expression system:
3363 dctdnoiz=e='gte(c, 4.5*3)'
3366 Violent denoise using a block size of @code{16x16}:
3374 Drop duplicated frames at regular intervals.
3376 The filter accepts the following options:
3380 Set the number of frames from which one will be dropped. Setting this to
3381 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3382 Default is @code{5}.
3385 Set the threshold for duplicate detection. If the difference metric for a frame
3386 is less than or equal to this value, then it is declared as duplicate. Default
3390 Set scene change threshold. Default is @code{15}.
3394 Set the size of the x and y-axis blocks used during metric calculations.
3395 Larger blocks give better noise suppression, but also give worse detection of
3396 small movements. Must be a power of two. Default is @code{32}.
3399 Mark main input as a pre-processed input and activate clean source input
3400 stream. This allows the input to be pre-processed with various filters to help
3401 the metrics calculation while keeping the frame selection lossless. When set to
3402 @code{1}, the first stream is for the pre-processed input, and the second
3403 stream is the clean source from where the kept frames are chosen. Default is
3407 Set whether or not chroma is considered in the metric calculations. Default is
3413 Remove judder produced by partially interlaced telecined content.
3415 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3416 source was partially telecined content then the output of @code{pullup,dejudder}
3417 will have a variable frame rate. May change the recorded frame rate of the
3418 container. Aside from that change, this filter will not affect constant frame
3421 The option available in this filter is:
3425 Specify the length of the window over which the judder repeats.
3427 Accepts any integer greater than 1. Useful values are:
3431 If the original was telecined from 24 to 30 fps (Film to NTSC).
3434 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3437 If a mixture of the two.
3440 The default is @samp{4}.
3445 Suppress a TV station logo by a simple interpolation of the surrounding
3446 pixels. Just set a rectangle covering the logo and watch it disappear
3447 (and sometimes something even uglier appear - your mileage may vary).
3449 It accepts the following parameters:
3454 Specify the top left corner coordinates of the logo. They must be
3459 Specify the width and height of the logo to clear. They must be
3463 Specify the thickness of the fuzzy edge of the rectangle (added to
3464 @var{w} and @var{h}). The default value is 4.
3467 When set to 1, a green rectangle is drawn on the screen to simplify
3468 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3469 The default value is 0.
3471 The rectangle is drawn on the outermost pixels which will be (partly)
3472 replaced with interpolated values. The values of the next pixels
3473 immediately outside this rectangle in each direction will be used to
3474 compute the interpolated pixel values inside the rectangle.
3478 @subsection Examples
3482 Set a rectangle covering the area with top left corner coordinates 0,0
3483 and size 100x77, and a band of size 10:
3485 delogo=x=0:y=0:w=100:h=77:band=10
3492 Attempt to fix small changes in horizontal and/or vertical shift. This
3493 filter helps remove camera shake from hand-holding a camera, bumping a
3494 tripod, moving on a vehicle, etc.
3496 The filter accepts the following options:
3504 Specify a rectangular area where to limit the search for motion
3506 If desired the search for motion vectors can be limited to a
3507 rectangular area of the frame defined by its top left corner, width
3508 and height. These parameters have the same meaning as the drawbox
3509 filter which can be used to visualise the position of the bounding
3512 This is useful when simultaneous movement of subjects within the frame
3513 might be confused for camera motion by the motion vector search.
3515 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3516 then the full frame is used. This allows later options to be set
3517 without specifying the bounding box for the motion vector search.
3519 Default - search the whole frame.
3523 Specify the maximum extent of movement in x and y directions in the
3524 range 0-64 pixels. Default 16.
3527 Specify how to generate pixels to fill blanks at the edge of the
3528 frame. Available values are:
3531 Fill zeroes at blank locations
3533 Original image at blank locations
3535 Extruded edge value at blank locations
3537 Mirrored edge at blank locations
3539 Default value is @samp{mirror}.
3542 Specify the blocksize to use for motion search. Range 4-128 pixels,
3546 Specify the contrast threshold for blocks. Only blocks with more than
3547 the specified contrast (difference between darkest and lightest
3548 pixels) will be considered. Range 1-255, default 125.
3551 Specify the search strategy. Available values are:
3554 Set exhaustive search
3556 Set less exhaustive search.
3558 Default value is @samp{exhaustive}.
3561 If set then a detailed log of the motion search is written to the
3565 If set to 1, specify using OpenCL capabilities, only available if
3566 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3572 Draw a colored box on the input image.
3574 It accepts the following parameters:
3579 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3583 The expressions which specify the width and height of the box; if 0 they are interpreted as
3584 the input width and height. It defaults to 0.
3587 Specify the color of the box to write. For the general syntax of this option,
3588 check the "Color" section in the ffmpeg-utils manual. If the special
3589 value @code{invert} is used, the box edge color is the same as the
3590 video with inverted luma.
3593 The expression which sets the thickness of the box edge. Default value is @code{3}.
3595 See below for the list of accepted constants.
3598 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3599 following constants:
3603 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3607 horizontal and vertical chroma subsample values. For example for the
3608 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3612 The input width and height.
3615 The input sample aspect ratio.
3619 The x and y offset coordinates where the box is drawn.
3623 The width and height of the drawn box.
3626 The thickness of the drawn box.
3628 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3629 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3633 @subsection Examples
3637 Draw a black box around the edge of the input image:
3643 Draw a box with color red and an opacity of 50%:
3645 drawbox=10:20:200:60:red@@0.5
3648 The previous example can be specified as:
3650 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3654 Fill the box with pink color:
3656 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3660 Draw a 2-pixel red 2.40:1 mask:
3662 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
3668 Draw a grid on the input image.
3670 It accepts the following parameters:
3675 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3679 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3680 input width and height, respectively, minus @code{thickness}, so image gets
3681 framed. Default to 0.
3684 Specify the color of the grid. For the general syntax of this option,
3685 check the "Color" section in the ffmpeg-utils manual. If the special
3686 value @code{invert} is used, the grid color is the same as the
3687 video with inverted luma.
3690 The expression which sets the thickness of the grid line. Default value is @code{1}.
3692 See below for the list of accepted constants.
3695 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3696 following constants:
3700 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3704 horizontal and vertical chroma subsample values. For example for the
3705 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3709 The input grid cell width and height.
3712 The input sample aspect ratio.
3716 The x and y coordinates of some point of grid intersection (meant to configure offset).
3720 The width and height of the drawn cell.
3723 The thickness of the drawn cell.
3725 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3726 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3730 @subsection Examples
3734 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3736 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3740 Draw a white 3x3 grid with an opacity of 50%:
3742 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3749 Draw a text string or text from a specified file on top of a video, using the
3750 libfreetype library.
3752 To enable compilation of this filter, you need to configure FFmpeg with
3753 @code{--enable-libfreetype}.
3754 To enable default font fallback and the @var{font} option you need to
3755 configure FFmpeg with @code{--enable-libfontconfig}.
3756 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3757 @code{--enable-libfribidi}.
3761 It accepts the following parameters:
3766 Used to draw a box around text using the background color.
3767 The value must be either 1 (enable) or 0 (disable).
3768 The default value of @var{box} is 0.
3771 The color to be used for drawing box around text. For the syntax of this
3772 option, check the "Color" section in the ffmpeg-utils manual.
3774 The default value of @var{boxcolor} is "white".
3777 Set the width of the border to be drawn around the text using @var{bordercolor}.
3778 The default value of @var{borderw} is 0.
3781 Set the color to be used for drawing border around text. For the syntax of this
3782 option, check the "Color" section in the ffmpeg-utils manual.
3784 The default value of @var{bordercolor} is "black".
3787 Select how the @var{text} is expanded. Can be either @code{none},
3788 @code{strftime} (deprecated) or
3789 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3793 If true, check and fix text coords to avoid clipping.
3796 The color to be used for drawing fonts. For the syntax of this option, check
3797 the "Color" section in the ffmpeg-utils manual.
3799 The default value of @var{fontcolor} is "black".
3801 @item fontcolor_expr
3802 String which is expanded the same way as @var{text} to obtain dynamic
3803 @var{fontcolor} value. By default this option has empty value and is not
3804 processed. When this option is set, it overrides @var{fontcolor} option.
3807 The font family to be used for drawing text. By default Sans.
3810 The font file to be used for drawing text. The path must be included.
3811 This parameter is mandatory if the fontconfig support is disabled.
3814 The font size to be used for drawing text.
3815 The default value of @var{fontsize} is 16.
3818 If set to 1, attempt to shape the text (for example, reverse the order of
3819 right-to-left text and join Arabic characters) before drawing it.
3820 Otherwise, just draw the text exactly as given.
3821 By default 1 (if supported).
3824 The flags to be used for loading the fonts.
3826 The flags map the corresponding flags supported by libfreetype, and are
3827 a combination of the following values:
3834 @item vertical_layout
3835 @item force_autohint
3838 @item ignore_global_advance_width
3840 @item ignore_transform
3846 Default value is "default".
3848 For more information consult the documentation for the FT_LOAD_*
3852 The color to be used for drawing a shadow behind the drawn text. For the
3853 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3855 The default value of @var{shadowcolor} is "black".
3859 The x and y offsets for the text shadow position with respect to the
3860 position of the text. They can be either positive or negative
3861 values. The default value for both is "0".
3864 The starting frame number for the n/frame_num variable. The default value
3868 The size in number of spaces to use for rendering the tab.
3872 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3873 format. It can be used with or without text parameter. @var{timecode_rate}
3874 option must be specified.
3876 @item timecode_rate, rate, r
3877 Set the timecode frame rate (timecode only).
3880 The text string to be drawn. The text must be a sequence of UTF-8
3882 This parameter is mandatory if no file is specified with the parameter
3886 A text file containing text to be drawn. The text must be a sequence
3887 of UTF-8 encoded characters.
3889 This parameter is mandatory if no text string is specified with the
3890 parameter @var{text}.
3892 If both @var{text} and @var{textfile} are specified, an error is thrown.
3895 If set to 1, the @var{textfile} will be reloaded before each frame.
3896 Be sure to update it atomically, or it may be read partially, or even fail.
3900 The expressions which specify the offsets where text will be drawn
3901 within the video frame. They are relative to the top/left border of the
3904 The default value of @var{x} and @var{y} is "0".
3906 See below for the list of accepted constants and functions.
3909 The parameters for @var{x} and @var{y} are expressions containing the
3910 following constants and functions:
3914 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3918 horizontal and vertical chroma subsample values. For example for the
3919 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3922 the height of each text line
3930 @item max_glyph_a, ascent
3931 the maximum distance from the baseline to the highest/upper grid
3932 coordinate used to place a glyph outline point, for all the rendered
3934 It is a positive value, due to the grid's orientation with the Y axis
3937 @item max_glyph_d, descent
3938 the maximum distance from the baseline to the lowest grid coordinate
3939 used to place a glyph outline point, for all the rendered glyphs.
3940 This is a negative value, due to the grid's orientation, with the Y axis
3944 maximum glyph height, that is the maximum height for all the glyphs
3945 contained in the rendered text, it is equivalent to @var{ascent} -
3949 maximum glyph width, that is the maximum width for all the glyphs
3950 contained in the rendered text
3953 the number of input frame, starting from 0
3955 @item rand(min, max)
3956 return a random number included between @var{min} and @var{max}
3959 The input sample aspect ratio.
3962 timestamp expressed in seconds, NAN if the input timestamp is unknown
3965 the height of the rendered text
3968 the width of the rendered text
3972 the x and y offset coordinates where the text is drawn.
3974 These parameters allow the @var{x} and @var{y} expressions to refer
3975 each other, so you can for example specify @code{y=x/dar}.
3978 @anchor{drawtext_expansion}
3979 @subsection Text expansion
3981 If @option{expansion} is set to @code{strftime},
3982 the filter recognizes strftime() sequences in the provided text and
3983 expands them accordingly. Check the documentation of strftime(). This
3984 feature is deprecated.
3986 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3988 If @option{expansion} is set to @code{normal} (which is the default),
3989 the following expansion mechanism is used.
3991 The backslash character '\', followed by any character, always expands to
3992 the second character.
3994 Sequence of the form @code{%@{...@}} are expanded. The text between the
3995 braces is a function name, possibly followed by arguments separated by ':'.
3996 If the arguments contain special characters or delimiters (':' or '@}'),
3997 they should be escaped.
3999 Note that they probably must also be escaped as the value for the
4000 @option{text} option in the filter argument string and as the filter
4001 argument in the filtergraph description, and possibly also for the shell,
4002 that makes up to four levels of escaping; using a text file avoids these
4005 The following functions are available:
4010 The expression evaluation result.
4012 It must take one argument specifying the expression to be evaluated,
4013 which accepts the same constants and functions as the @var{x} and
4014 @var{y} values. Note that not all constants should be used, for
4015 example the text size is not known when evaluating the expression, so
4016 the constants @var{text_w} and @var{text_h} will have an undefined
4019 @item expr_int_format, eif
4020 Evaluate the expression's value and output as formatted integer.
4022 First argument is expression to be evaluated, same as for @var{expr} function.
4023 Second argument specifies output format. Allowed values are 'x', 'X', 'd' and
4024 'u', they are treated exactly as in printf function.
4025 Third parameter is optional and sets the number of positions taken by output.
4026 Effectively this allows to add padding with zeros from the left.
4029 The time at which the filter is running, expressed in UTC.
4030 It can accept an argument: a strftime() format string.
4033 The time at which the filter is running, expressed in the local time zone.
4034 It can accept an argument: a strftime() format string.
4037 Frame metadata. It must take one argument specifying metadata key.
4040 The frame number, starting from 0.
4043 A 1 character description of the current picture type.
4046 The timestamp of the current frame.
4047 It can take up to two arguments.
4049 The first argument is the format of the timestamp; it defaults to @code{flt}
4050 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4051 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4053 The second argument is an offset added to the timestamp.
4057 @subsection Examples
4061 Draw "Test Text" with font FreeSerif, using the default values for the
4062 optional parameters.
4065 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4069 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4070 and y=50 (counting from the top-left corner of the screen), text is
4071 yellow with a red box around it. Both the text and the box have an
4075 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4076 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4079 Note that the double quotes are not necessary if spaces are not used
4080 within the parameter list.
4083 Show the text at the center of the video frame:
4085 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4089 Show a text line sliding from right to left in the last row of the video
4090 frame. The file @file{LONG_LINE} is assumed to contain a single line
4093 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4097 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4099 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4103 Draw a single green letter "g", at the center of the input video.
4104 The glyph baseline is placed at half screen height.
4106 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4110 Show text for 1 second every 3 seconds:
4112 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4116 Use fontconfig to set the font. Note that the colons need to be escaped.
4118 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4122 Print the date of a real-time encoding (see strftime(3)):
4124 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
4128 Show text fading in and out (appearing/disappearing):
4131 DS=1.0 # display start
4132 DE=10.0 # display end
4133 FID=1.5 # fade in duration
4134 FOD=5 # fade out duration
4135 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 @}"
4140 For more information about libfreetype, check:
4141 @url{http://www.freetype.org/}.
4143 For more information about fontconfig, check:
4144 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4146 For more information about libfribidi, check:
4147 @url{http://fribidi.org/}.
4151 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4153 The filter accepts the following options:
4158 Set low and high threshold values used by the Canny thresholding
4161 The high threshold selects the "strong" edge pixels, which are then
4162 connected through 8-connectivity with the "weak" edge pixels selected
4163 by the low threshold.
4165 @var{low} and @var{high} threshold values must be chosen in the range
4166 [0,1], and @var{low} should be lesser or equal to @var{high}.
4168 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4172 Define the drawing mode.
4176 Draw white/gray wires on black background.
4179 Mix the colors to create a paint/cartoon effect.
4182 Default value is @var{wires}.
4185 @subsection Examples
4189 Standard edge detection with custom values for the hysteresis thresholding:
4191 edgedetect=low=0.1:high=0.4
4195 Painting effect without thresholding:
4197 edgedetect=mode=colormix:high=0
4201 @section extractplanes
4203 Extract color channel components from input video stream into
4204 separate grayscale video streams.
4206 The filter accepts the following option:
4210 Set plane(s) to extract.
4212 Available values for planes are:
4223 Choosing planes not available in the input will result in an error.
4224 That means you cannot select @code{r}, @code{g}, @code{b} planes
4225 with @code{y}, @code{u}, @code{v} planes at same time.
4228 @subsection Examples
4232 Extract luma, u and v color channel component from input video frame
4233 into 3 grayscale outputs:
4235 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
4241 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4243 For each input image, the filter will compute the optimal mapping from
4244 the input to the output given the codebook length, that is the number
4245 of distinct output colors.
4247 This filter accepts the following options.
4250 @item codebook_length, l
4251 Set codebook length. The value must be a positive integer, and
4252 represents the number of distinct output colors. Default value is 256.
4255 Set the maximum number of iterations to apply for computing the optimal
4256 mapping. The higher the value the better the result and the higher the
4257 computation time. Default value is 1.
4260 Set a random seed, must be an integer included between 0 and
4261 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4262 will try to use a good random seed on a best effort basis.
4267 Apply a fade-in/out effect to the input video.
4269 It accepts the following parameters:
4273 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4275 Default is @code{in}.
4277 @item start_frame, s
4278 Specify the number of the frame to start applying the fade
4279 effect at. Default is 0.
4282 The number of frames that the fade effect lasts. At the end of the
4283 fade-in effect, the output video will have the same intensity as the input video.
4284 At the end of the fade-out transition, the output video will be filled with the
4285 selected @option{color}.
4289 If set to 1, fade only alpha channel, if one exists on the input.
4292 @item start_time, st
4293 Specify the timestamp (in seconds) of the frame to start to apply the fade
4294 effect. If both start_frame and start_time are specified, the fade will start at
4295 whichever comes last. Default is 0.
4298 The number of seconds for which the fade effect has to last. At the end of the
4299 fade-in effect the output video will have the same intensity as the input video,
4300 at the end of the fade-out transition the output video will be filled with the
4301 selected @option{color}.
4302 If both duration and nb_frames are specified, duration is used. Default is 0.
4305 Specify the color of the fade. Default is "black".
4308 @subsection Examples
4312 Fade in the first 30 frames of video:
4317 The command above is equivalent to:
4323 Fade out the last 45 frames of a 200-frame video:
4326 fade=type=out:start_frame=155:nb_frames=45
4330 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4332 fade=in:0:25, fade=out:975:25
4336 Make the first 5 frames yellow, then fade in from frame 5-24:
4338 fade=in:5:20:color=yellow
4342 Fade in alpha over first 25 frames of video:
4344 fade=in:0:25:alpha=1
4348 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4350 fade=t=in:st=5.5:d=0.5
4357 Extract a single field from an interlaced image using stride
4358 arithmetic to avoid wasting CPU time. The output frames are marked as
4361 The filter accepts the following options:
4365 Specify whether to extract the top (if the value is @code{0} or
4366 @code{top}) or the bottom field (if the value is @code{1} or
4372 Field matching filter for inverse telecine. It is meant to reconstruct the
4373 progressive frames from a telecined stream. The filter does not drop duplicated
4374 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4375 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4377 The separation of the field matching and the decimation is notably motivated by
4378 the possibility of inserting a de-interlacing filter fallback between the two.
4379 If the source has mixed telecined and real interlaced content,
4380 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4381 But these remaining combed frames will be marked as interlaced, and thus can be
4382 de-interlaced by a later filter such as @ref{yadif} before decimation.
4384 In addition to the various configuration options, @code{fieldmatch} can take an
4385 optional second stream, activated through the @option{ppsrc} option. If
4386 enabled, the frames reconstruction will be based on the fields and frames from
4387 this second stream. This allows the first input to be pre-processed in order to
4388 help the various algorithms of the filter, while keeping the output lossless
4389 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4390 or brightness/contrast adjustments can help.
4392 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4393 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4394 which @code{fieldmatch} is based on. While the semantic and usage are very
4395 close, some behaviour and options names can differ.
4397 The filter accepts the following options:
4401 Specify the assumed field order of the input stream. Available values are:
4405 Auto detect parity (use FFmpeg's internal parity value).
4407 Assume bottom field first.
4409 Assume top field first.
4412 Note that it is sometimes recommended not to trust the parity announced by the
4415 Default value is @var{auto}.
4418 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4419 sense that it won't risk creating jerkiness due to duplicate frames when
4420 possible, but if there are bad edits or blended fields it will end up
4421 outputting combed frames when a good match might actually exist. On the other
4422 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4423 but will almost always find a good frame if there is one. The other values are
4424 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4425 jerkiness and creating duplicate frames versus finding good matches in sections
4426 with bad edits, orphaned fields, blended fields, etc.
4428 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4430 Available values are:
4434 2-way matching (p/c)
4436 2-way matching, and trying 3rd match if still combed (p/c + n)
4438 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4440 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4441 still combed (p/c + n + u/b)
4443 3-way matching (p/c/n)
4445 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4446 detected as combed (p/c/n + u/b)
4449 The parenthesis at the end indicate the matches that would be used for that
4450 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4453 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4456 Default value is @var{pc_n}.
4459 Mark the main input stream as a pre-processed input, and enable the secondary
4460 input stream as the clean source to pick the fields from. See the filter
4461 introduction for more details. It is similar to the @option{clip2} feature from
4464 Default value is @code{0} (disabled).
4467 Set the field to match from. It is recommended to set this to the same value as
4468 @option{order} unless you experience matching failures with that setting. In
4469 certain circumstances changing the field that is used to match from can have a
4470 large impact on matching performance. Available values are:
4474 Automatic (same value as @option{order}).
4476 Match from the bottom field.
4478 Match from the top field.
4481 Default value is @var{auto}.
4484 Set whether or not chroma is included during the match comparisons. In most
4485 cases it is recommended to leave this enabled. You should set this to @code{0}
4486 only if your clip has bad chroma problems such as heavy rainbowing or other
4487 artifacts. Setting this to @code{0} could also be used to speed things up at
4488 the cost of some accuracy.
4490 Default value is @code{1}.
4494 These define an exclusion band which excludes the lines between @option{y0} and
4495 @option{y1} from being included in the field matching decision. An exclusion
4496 band can be used to ignore subtitles, a logo, or other things that may
4497 interfere with the matching. @option{y0} sets the starting scan line and
4498 @option{y1} sets the ending line; all lines in between @option{y0} and
4499 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4500 @option{y0} and @option{y1} to the same value will disable the feature.
4501 @option{y0} and @option{y1} defaults to @code{0}.
4504 Set the scene change detection threshold as a percentage of maximum change on
4505 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4506 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4507 @option{scthresh} is @code{[0.0, 100.0]}.
4509 Default value is @code{12.0}.
4512 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4513 account the combed scores of matches when deciding what match to use as the
4514 final match. Available values are:
4518 No final matching based on combed scores.
4520 Combed scores are only used when a scene change is detected.
4522 Use combed scores all the time.
4525 Default is @var{sc}.
4528 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4529 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4530 Available values are:
4534 No forced calculation.
4536 Force p/c/n calculations.
4538 Force p/c/n/u/b calculations.
4541 Default value is @var{none}.
4544 This is the area combing threshold used for combed frame detection. This
4545 essentially controls how "strong" or "visible" combing must be to be detected.
4546 Larger values mean combing must be more visible and smaller values mean combing
4547 can be less visible or strong and still be detected. Valid settings are from
4548 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4549 be detected as combed). This is basically a pixel difference value. A good
4550 range is @code{[8, 12]}.
4552 Default value is @code{9}.
4555 Sets whether or not chroma is considered in the combed frame decision. Only
4556 disable this if your source has chroma problems (rainbowing, etc.) that are
4557 causing problems for the combed frame detection with chroma enabled. Actually,
4558 using @option{chroma}=@var{0} is usually more reliable, except for the case
4559 where there is chroma only combing in the source.
4561 Default value is @code{0}.
4565 Respectively set the x-axis and y-axis size of the window used during combed
4566 frame detection. This has to do with the size of the area in which
4567 @option{combpel} pixels are required to be detected as combed for a frame to be
4568 declared combed. See the @option{combpel} parameter description for more info.
4569 Possible values are any number that is a power of 2 starting at 4 and going up
4572 Default value is @code{16}.
4575 The number of combed pixels inside any of the @option{blocky} by
4576 @option{blockx} size blocks on the frame for the frame to be detected as
4577 combed. While @option{cthresh} controls how "visible" the combing must be, this
4578 setting controls "how much" combing there must be in any localized area (a
4579 window defined by the @option{blockx} and @option{blocky} settings) on the
4580 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4581 which point no frames will ever be detected as combed). This setting is known
4582 as @option{MI} in TFM/VFM vocabulary.
4584 Default value is @code{80}.
4587 @anchor{p/c/n/u/b meaning}
4588 @subsection p/c/n/u/b meaning
4590 @subsubsection p/c/n
4592 We assume the following telecined stream:
4595 Top fields: 1 2 2 3 4
4596 Bottom fields: 1 2 3 4 4
4599 The numbers correspond to the progressive frame the fields relate to. Here, the
4600 first two frames are progressive, the 3rd and 4th are combed, and so on.
4602 When @code{fieldmatch} is configured to run a matching from bottom
4603 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4608 B 1 2 3 4 4 <-- matching reference
4617 As a result of the field matching, we can see that some frames get duplicated.
4618 To perform a complete inverse telecine, you need to rely on a decimation filter
4619 after this operation. See for instance the @ref{decimate} filter.
4621 The same operation now matching from top fields (@option{field}=@var{top})
4626 T 1 2 2 3 4 <-- matching reference
4636 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4637 basically, they refer to the frame and field of the opposite parity:
4640 @item @var{p} matches the field of the opposite parity in the previous frame
4641 @item @var{c} matches the field of the opposite parity in the current frame
4642 @item @var{n} matches the field of the opposite parity in the next frame
4647 The @var{u} and @var{b} matching are a bit special in the sense that they match
4648 from the opposite parity flag. In the following examples, we assume that we are
4649 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4650 'x' is placed above and below each matched fields.
4652 With bottom matching (@option{field}=@var{bottom}):
4657 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4658 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4666 With top matching (@option{field}=@var{top}):
4671 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4672 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4680 @subsection Examples
4682 Simple IVTC of a top field first telecined stream:
4684 fieldmatch=order=tff:combmatch=none, decimate
4687 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4689 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4694 Transform the field order of the input video.
4696 It accepts the following parameters:
4701 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4702 for bottom field first.
4705 The default value is @samp{tff}.
4707 The transformation is done by shifting the picture content up or down
4708 by one line, and filling the remaining line with appropriate picture content.
4709 This method is consistent with most broadcast field order converters.
4711 If the input video is not flagged as being interlaced, or it is already
4712 flagged as being of the required output field order, then this filter does
4713 not alter the incoming video.
4715 It is very useful when converting to or from PAL DV material,
4716 which is bottom field first.
4720 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4725 Buffer input images and send them when they are requested.
4727 It is mainly useful when auto-inserted by the libavfilter
4730 It does not take parameters.
4735 Convert the input video to one of the specified pixel formats.
4736 Libavfilter will try to pick one that is suitable as input to
4739 It accepts the following parameters:
4743 A '|'-separated list of pixel format names, such as
4744 "pix_fmts=yuv420p|monow|rgb24".
4748 @subsection Examples
4752 Convert the input video to the @var{yuv420p} format
4754 format=pix_fmts=yuv420p
4757 Convert the input video to any of the formats in the list
4759 format=pix_fmts=yuv420p|yuv444p|yuv410p
4766 Convert the video to specified constant frame rate by duplicating or dropping
4767 frames as necessary.
4769 It accepts the following parameters:
4773 The desired output frame rate. The default is @code{25}.
4778 Possible values are:
4781 zero round towards 0
4785 round towards -infinity
4787 round towards +infinity
4791 The default is @code{near}.
4794 Assume the first PTS should be the given value, in seconds. This allows for
4795 padding/trimming at the start of stream. By default, no assumption is made
4796 about the first frame's expected PTS, so no padding or trimming is done.
4797 For example, this could be set to 0 to pad the beginning with duplicates of
4798 the first frame if a video stream starts after the audio stream or to trim any
4799 frames with a negative PTS.
4803 Alternatively, the options can be specified as a flat string:
4804 @var{fps}[:@var{round}].
4806 See also the @ref{setpts} filter.
4808 @subsection Examples
4812 A typical usage in order to set the fps to 25:
4818 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4820 fps=fps=film:round=near
4826 Pack two different video streams into a stereoscopic video, setting proper
4827 metadata on supported codecs. The two views should have the same size and
4828 framerate and processing will stop when the shorter video ends. Please note
4829 that you may conveniently adjust view properties with the @ref{scale} and
4832 It accepts the following parameters:
4836 The desired packing format. Supported values are:
4841 The views are next to each other (default).
4844 The views are on top of each other.
4847 The views are packed by line.
4850 The views are packed by column.
4853 The views are temporally interleaved.
4862 # Convert left and right views into a frame-sequential video
4863 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4865 # Convert views into a side-by-side video with the same output resolution as the input
4866 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
4871 Select one frame every N-th frame.
4873 This filter accepts the following option:
4876 Select frame after every @code{step} frames.
4877 Allowed values are positive integers higher than 0. Default value is @code{1}.
4883 Apply a frei0r effect to the input video.
4885 To enable the compilation of this filter, you need to install the frei0r
4886 header and configure FFmpeg with @code{--enable-frei0r}.
4888 It accepts the following parameters:
4893 The name of the frei0r effect to load. If the environment variable
4894 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
4895 directories specified by the colon-separated list in @env{FREIOR_PATH}.
4896 Otherwise, the standard frei0r paths are searched, in this order:
4897 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4898 @file{/usr/lib/frei0r-1/}.
4901 A '|'-separated list of parameters to pass to the frei0r effect.
4905 A frei0r effect parameter can be a boolean (its value is either
4906 "y" or "n"), a double, a color (specified as
4907 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
4908 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
4909 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
4910 @var{X} and @var{Y} are floating point numbers) and/or a string.
4912 The number and types of parameters depend on the loaded effect. If an
4913 effect parameter is not specified, the default value is set.
4915 @subsection Examples
4919 Apply the distort0r effect, setting the first two double parameters:
4921 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4925 Apply the colordistance effect, taking a color as the first parameter:
4927 frei0r=colordistance:0.2/0.3/0.4
4928 frei0r=colordistance:violet
4929 frei0r=colordistance:0x112233
4933 Apply the perspective effect, specifying the top left and top right image
4936 frei0r=perspective:0.2/0.2|0.8/0.2
4940 For more information, see
4941 @url{http://frei0r.dyne.org}
4945 The filter accepts the following options:
4949 Set the luminance expression.
4951 Set the chrominance blue expression.
4953 Set the chrominance red expression.
4955 Set the alpha expression.
4957 Set the red expression.
4959 Set the green expression.
4961 Set the blue expression.
4964 The colorspace is selected according to the specified options. If one
4965 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4966 options is specified, the filter will automatically select a YCbCr
4967 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4968 @option{blue_expr} options is specified, it will select an RGB
4971 If one of the chrominance expression is not defined, it falls back on the other
4972 one. If no alpha expression is specified it will evaluate to opaque value.
4973 If none of chrominance expressions are specified, they will evaluate
4974 to the luminance expression.
4976 The expressions can use the following variables and functions:
4980 The sequential number of the filtered frame, starting from @code{0}.
4984 The coordinates of the current sample.
4988 The width and height of the image.
4992 Width and height scale depending on the currently filtered plane. It is the
4993 ratio between the corresponding luma plane number of pixels and the current
4994 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4995 @code{0.5,0.5} for chroma planes.
4998 Time of the current frame, expressed in seconds.
5001 Return the value of the pixel at location (@var{x},@var{y}) of the current
5005 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
5009 Return the value of the pixel at location (@var{x},@var{y}) of the
5010 blue-difference chroma plane. Return 0 if there is no such plane.
5013 Return the value of the pixel at location (@var{x},@var{y}) of the
5014 red-difference chroma plane. Return 0 if there is no such plane.
5019 Return the value of the pixel at location (@var{x},@var{y}) of the
5020 red/green/blue component. Return 0 if there is no such component.
5023 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
5024 plane. Return 0 if there is no such plane.
5027 For functions, if @var{x} and @var{y} are outside the area, the value will be
5028 automatically clipped to the closer edge.
5030 @subsection Examples
5034 Flip the image horizontally:
5040 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5041 wavelength of 100 pixels:
5043 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5047 Generate a fancy enigmatic moving light:
5049 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
5053 Generate a quick emboss effect:
5055 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5059 Modify RGB components depending on pixel position:
5061 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5067 Fix the banding artifacts that are sometimes introduced into nearly flat
5068 regions by truncation to 8bit color depth.
5069 Interpolate the gradients that should go where the bands are, and
5072 It is designed for playback only. Do not use it prior to
5073 lossy compression, because compression tends to lose the dither and
5074 bring back the bands.
5076 It accepts the following parameters:
5081 The maximum amount by which the filter will change any one pixel. This is also
5082 the threshold for detecting nearly flat regions. Acceptable values range from
5083 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5087 The neighborhood to fit the gradient to. A larger radius makes for smoother
5088 gradients, but also prevents the filter from modifying the pixels near detailed
5089 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5090 values will be clipped to the valid range.
5094 Alternatively, the options can be specified as a flat string:
5095 @var{strength}[:@var{radius}]
5097 @subsection Examples
5101 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5107 Specify radius, omitting the strength (which will fall-back to the default
5118 Apply a Hald CLUT to a video stream.
5120 First input is the video stream to process, and second one is the Hald CLUT.
5121 The Hald CLUT input can be a simple picture or a complete video stream.
5123 The filter accepts the following options:
5127 Force termination when the shortest input terminates. Default is @code{0}.
5129 Continue applying the last CLUT after the end of the stream. A value of
5130 @code{0} disable the filter after the last frame of the CLUT is reached.
5131 Default is @code{1}.
5134 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5135 filters share the same internals).
5137 More information about the Hald CLUT can be found on Eskil Steenberg's website
5138 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5140 @subsection Workflow examples
5142 @subsubsection Hald CLUT video stream
5144 Generate an identity Hald CLUT stream altered with various effects:
5146 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
5149 Note: make sure you use a lossless codec.
5151 Then use it with @code{haldclut} to apply it on some random stream:
5153 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5156 The Hald CLUT will be applied to the 10 first seconds (duration of
5157 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5158 to the remaining frames of the @code{mandelbrot} stream.
5160 @subsubsection Hald CLUT with preview
5162 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5163 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5164 biggest possible square starting at the top left of the picture. The remaining
5165 padding pixels (bottom or right) will be ignored. This area can be used to add
5166 a preview of the Hald CLUT.
5168 Typically, the following generated Hald CLUT will be supported by the
5169 @code{haldclut} filter:
5172 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5173 pad=iw+320 [padded_clut];
5174 smptebars=s=320x256, split [a][b];
5175 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5176 [main][b] overlay=W-320" -frames:v 1 clut.png
5179 It contains the original and a preview of the effect of the CLUT: SMPTE color
5180 bars are displayed on the right-top, and below the same color bars processed by
5183 Then, the effect of this Hald CLUT can be visualized with:
5185 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5190 Flip the input video horizontally.
5192 For example, to horizontally flip the input video with @command{ffmpeg}:
5194 ffmpeg -i in.avi -vf "hflip" out.avi
5198 This filter applies a global color histogram equalization on a
5201 It can be used to correct video that has a compressed range of pixel
5202 intensities. The filter redistributes the pixel intensities to
5203 equalize their distribution across the intensity range. It may be
5204 viewed as an "automatically adjusting contrast filter". This filter is
5205 useful only for correcting degraded or poorly captured source
5208 The filter accepts the following options:
5212 Determine the amount of equalization to be applied. As the strength
5213 is reduced, the distribution of pixel intensities more-and-more
5214 approaches that of the input frame. The value must be a float number
5215 in the range [0,1] and defaults to 0.200.
5218 Set the maximum intensity that can generated and scale the output
5219 values appropriately. The strength should be set as desired and then
5220 the intensity can be limited if needed to avoid washing-out. The value
5221 must be a float number in the range [0,1] and defaults to 0.210.
5224 Set the antibanding level. If enabled the filter will randomly vary
5225 the luminance of output pixels by a small amount to avoid banding of
5226 the histogram. Possible values are @code{none}, @code{weak} or
5227 @code{strong}. It defaults to @code{none}.
5232 Compute and draw a color distribution histogram for the input video.
5234 The computed histogram is a representation of the color component
5235 distribution in an image.
5237 The filter accepts the following options:
5243 It accepts the following values:
5246 Standard histogram that displays the color components distribution in an
5247 image. Displays color graph for each color component. Shows distribution of
5248 the Y, U, V, A or R, G, B components, depending on input format, in the
5249 current frame. Below each graph a color component scale meter is shown.
5252 Displays chroma values (U/V color placement) in a two dimensional
5253 graph (which is called a vectorscope). The brighter a pixel in the
5254 vectorscope, the more pixels of the input frame correspond to that pixel
5255 (i.e., more pixels have this chroma value). The V component is displayed on
5256 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5257 side being V = 255. The U component is displayed on the vertical (Y) axis,
5258 with the top representing U = 0 and the bottom representing U = 255.
5260 The position of a white pixel in the graph corresponds to the chroma value of
5261 a pixel of the input clip. The graph can therefore be used to read the hue
5262 (color flavor) and the saturation (the dominance of the hue in the color). As
5263 the hue of a color changes, it moves around the square. At the center of the
5264 square the saturation is zero, which means that the corresponding pixel has no
5265 color. If the amount of a specific color is increased (while leaving the other
5266 colors unchanged) the saturation increases, and the indicator moves towards
5267 the edge of the square.
5270 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5274 Per row/column color component graph. In row mode, the graph on the left side
5275 represents color component value 0 and the right side represents value = 255.
5276 In column mode, the top side represents color component value = 0 and bottom
5277 side represents value = 255.
5279 Default value is @code{levels}.
5282 Set height of level in @code{levels}. Default value is @code{200}.
5283 Allowed range is [50, 2048].
5286 Set height of color scale in @code{levels}. Default value is @code{12}.
5287 Allowed range is [0, 40].
5290 Set step for @code{waveform} mode. Smaller values are useful to find out how
5291 many values of the same luminance are distributed across input rows/columns.
5292 Default value is @code{10}. Allowed range is [1, 255].
5295 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5296 Default is @code{row}.
5298 @item waveform_mirror
5299 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5300 means mirrored. In mirrored mode, higher values will be represented on the left
5301 side for @code{row} mode and at the top for @code{column} mode. Default is
5302 @code{0} (unmirrored).
5305 Set display mode for @code{waveform} and @code{levels}.
5306 It accepts the following values:
5309 Display separate graph for the color components side by side in
5310 @code{row} waveform mode or one below the other in @code{column} waveform mode
5311 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5312 per color component graphs are placed below each other.
5314 Using this display mode in @code{waveform} histogram mode makes it easy to
5315 spot color casts in the highlights and shadows of an image, by comparing the
5316 contours of the top and the bottom graphs of each waveform. Since whites,
5317 grays, and blacks are characterized by exactly equal amounts of red, green,
5318 and blue, neutral areas of the picture should display three waveforms of
5319 roughly equal width/height. If not, the correction is easy to perform by
5320 making level adjustments the three waveforms.
5323 Presents information identical to that in the @code{parade}, except
5324 that the graphs representing color components are superimposed directly
5327 This display mode in @code{waveform} histogram mode makes it easier to spot
5328 relative differences or similarities in overlapping areas of the color
5329 components that are supposed to be identical, such as neutral whites, grays,
5332 Default is @code{parade}.
5335 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5336 Default is @code{linear}.
5339 @subsection Examples
5344 Calculate and draw histogram:
5346 ffplay -i input -vf histogram
5354 This is a high precision/quality 3d denoise filter. It aims to reduce
5355 image noise, producing smooth images and making still images really
5356 still. It should enhance compressibility.
5358 It accepts the following optional parameters:
5362 A non-negative floating point number which specifies spatial luma strength.
5365 @item chroma_spatial
5366 A non-negative floating point number which specifies spatial chroma strength.
5367 It defaults to 3.0*@var{luma_spatial}/4.0.
5370 A floating point number which specifies luma temporal strength. It defaults to
5371 6.0*@var{luma_spatial}/4.0.
5374 A floating point number which specifies chroma temporal strength. It defaults to
5375 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5380 Apply a high-quality magnification filter designed for pixel art. This filter
5381 was originally created by Maxim Stepin.
5383 It accepts the following option:
5387 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5388 @code{hq3x} and @code{4} for @code{hq4x}.
5389 Default is @code{3}.
5394 Modify the hue and/or the saturation of the input.
5396 It accepts the following parameters:
5400 Specify the hue angle as a number of degrees. It accepts an expression,
5401 and defaults to "0".
5404 Specify the saturation in the [-10,10] range. It accepts an expression and
5408 Specify the hue angle as a number of radians. It accepts an
5409 expression, and defaults to "0".
5412 Specify the brightness in the [-10,10] range. It accepts an expression and
5416 @option{h} and @option{H} are mutually exclusive, and can't be
5417 specified at the same time.
5419 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5420 expressions containing the following constants:
5424 frame count of the input frame starting from 0
5427 presentation timestamp of the input frame expressed in time base units
5430 frame rate of the input video, NAN if the input frame rate is unknown
5433 timestamp expressed in seconds, NAN if the input timestamp is unknown
5436 time base of the input video
5439 @subsection Examples
5443 Set the hue to 90 degrees and the saturation to 1.0:
5449 Same command but expressing the hue in radians:
5455 Rotate hue and make the saturation swing between 0
5456 and 2 over a period of 1 second:
5458 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5462 Apply a 3 seconds saturation fade-in effect starting at 0:
5467 The general fade-in expression can be written as:
5469 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5473 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5475 hue="s=max(0\, min(1\, (8-t)/3))"
5478 The general fade-out expression can be written as:
5480 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5485 @subsection Commands
5487 This filter supports the following commands:
5493 Modify the hue and/or the saturation and/or brightness of the input video.
5494 The command accepts the same syntax of the corresponding option.
5496 If the specified expression is not valid, it is kept at its current
5502 Detect video interlacing type.
5504 This filter tries to detect if the input is interlaced or progressive,
5505 top or bottom field first.
5507 The filter accepts the following options:
5511 Set interlacing threshold.
5513 Set progressive threshold.
5518 Deinterleave or interleave fields.
5520 This filter allows one to process interlaced images fields without
5521 deinterlacing them. Deinterleaving splits the input frame into 2
5522 fields (so called half pictures). Odd lines are moved to the top
5523 half of the output image, even lines to the bottom half.
5524 You can process (filter) them independently and then re-interleave them.
5526 The filter accepts the following options:
5530 @item chroma_mode, c
5532 Available values for @var{luma_mode}, @var{chroma_mode} and
5533 @var{alpha_mode} are:
5539 @item deinterleave, d
5540 Deinterleave fields, placing one above the other.
5543 Interleave fields. Reverse the effect of deinterleaving.
5545 Default value is @code{none}.
5548 @item chroma_swap, cs
5549 @item alpha_swap, as
5550 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5555 Simple interlacing filter from progressive contents. This interleaves upper (or
5556 lower) lines from odd frames with lower (or upper) lines from even frames,
5557 halving the frame rate and preserving image height.
5560 Original Original New Frame
5561 Frame 'j' Frame 'j+1' (tff)
5562 ========== =========== ==================
5563 Line 0 --------------------> Frame 'j' Line 0
5564 Line 1 Line 1 ----> Frame 'j+1' Line 1
5565 Line 2 ---------------------> Frame 'j' Line 2
5566 Line 3 Line 3 ----> Frame 'j+1' Line 3
5568 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5571 It accepts the following optional parameters:
5575 This determines whether the interlaced frame is taken from the even
5576 (tff - default) or odd (bff) lines of the progressive frame.
5579 Enable (default) or disable the vertical lowpass filter to avoid twitter
5580 interlacing and reduce moire patterns.
5585 Deinterlace input video by applying Donald Graft's adaptive kernel
5586 deinterling. Work on interlaced parts of a video to produce
5589 The description of the accepted parameters follows.
5593 Set the threshold which affects the filter's tolerance when
5594 determining if a pixel line must be processed. It must be an integer
5595 in the range [0,255] and defaults to 10. A value of 0 will result in
5596 applying the process on every pixels.
5599 Paint pixels exceeding the threshold value to white if set to 1.
5603 Set the fields order. Swap fields if set to 1, leave fields alone if
5607 Enable additional sharpening if set to 1. Default is 0.
5610 Enable twoway sharpening if set to 1. Default is 0.
5613 @subsection Examples
5617 Apply default values:
5619 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5623 Enable additional sharpening:
5629 Paint processed pixels in white:
5635 @section lenscorrection
5637 Correct radial lens distortion
5639 This filter can be used to correct for radial distortion as can result from the use
5640 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
5641 one can use tools available for example as part of opencv or simply trial-and-error.
5642 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
5643 and extract the k1 and k2 coefficients from the resulting matrix.
5645 Note that effectively the same filter is available in the open-source tools Krita and
5646 Digikam from the KDE project.
5648 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
5649 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
5650 brightness distribution, so you may want to use both filters together in certain
5651 cases, though you will have to take care of ordering, i.e. whether vignetting should
5652 be applied before or after lens correction.
5656 The filter accepts the following options:
5660 Relative x-coordinate of the focal point of the image, and thereby the center of the
5661 distrortion. This value has a range [0,1] and is expressed as fractions of the image
5664 Relative y-coordinate of the focal point of the image, and thereby the center of the
5665 distrortion. This value has a range [0,1] and is expressed as fractions of the image
5668 Coefficient of the quadratic correction term. 0.5 means no correction.
5670 Coefficient of the double quadratic correction term. 0.5 means no correction.
5673 The formula that generates the correction is:
5675 @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)
5677 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
5678 distances from the focal point in the source and target images, respectively.
5683 Apply a 3D LUT to an input video.
5685 The filter accepts the following options:
5689 Set the 3D LUT file name.
5691 Currently supported formats:
5703 Select interpolation mode.
5705 Available values are:
5709 Use values from the nearest defined point.
5711 Interpolate values using the 8 points defining a cube.
5713 Interpolate values using a tetrahedron.
5717 @section lut, lutrgb, lutyuv
5719 Compute a look-up table for binding each pixel component input value
5720 to an output value, and apply it to the input video.
5722 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5723 to an RGB input video.
5725 These filters accept the following parameters:
5728 set first pixel component expression
5730 set second pixel component expression
5732 set third pixel component expression
5734 set fourth pixel component expression, corresponds to the alpha component
5737 set red component expression
5739 set green component expression
5741 set blue component expression
5743 alpha component expression
5746 set Y/luminance component expression
5748 set U/Cb component expression
5750 set V/Cr component expression
5753 Each of them specifies the expression to use for computing the lookup table for
5754 the corresponding pixel component values.
5756 The exact component associated to each of the @var{c*} options depends on the
5759 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5760 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5762 The expressions can contain the following constants and functions:
5767 The input width and height.
5770 The input value for the pixel component.
5773 The input value, clipped to the @var{minval}-@var{maxval} range.
5776 The maximum value for the pixel component.
5779 The minimum value for the pixel component.
5782 The negated value for the pixel component value, clipped to the
5783 @var{minval}-@var{maxval} range; it corresponds to the expression
5784 "maxval-clipval+minval".
5787 The computed value in @var{val}, clipped to the
5788 @var{minval}-@var{maxval} range.
5790 @item gammaval(gamma)
5791 The computed gamma correction value of the pixel component value,
5792 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5794 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5798 All expressions default to "val".
5800 @subsection Examples
5806 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5807 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5810 The above is the same as:
5812 lutrgb="r=negval:g=negval:b=negval"
5813 lutyuv="y=negval:u=negval:v=negval"
5823 Remove chroma components, turning the video into a graytone image:
5825 lutyuv="u=128:v=128"
5829 Apply a luma burning effect:
5835 Remove green and blue components:
5841 Set a constant alpha channel value on input:
5843 format=rgba,lutrgb=a="maxval-minval/2"
5847 Correct luminance gamma by a factor of 0.5:
5849 lutyuv=y=gammaval(0.5)
5853 Discard least significant bits of luma:
5855 lutyuv=y='bitand(val, 128+64+32)'
5859 @section mergeplanes
5861 Merge color channel components from several video streams.
5863 The filter accepts up to 4 input streams, and merge selected input
5864 planes to the output video.
5866 This filter accepts the following options:
5869 Set input to output plane mapping. Default is @code{0}.
5871 The mappings is specified as a bitmap. It should be specified as a
5872 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5873 mapping for the first plane of the output stream. 'A' sets the number of
5874 the input stream to use (from 0 to 3), and 'a' the plane number of the
5875 corresponding input to use (from 0 to 3). The rest of the mappings is
5876 similar, 'Bb' describes the mapping for the output stream second
5877 plane, 'Cc' describes the mapping for the output stream third plane and
5878 'Dd' describes the mapping for the output stream fourth plane.
5881 Set output pixel format. Default is @code{yuva444p}.
5884 @subsection Examples
5888 Merge three gray video streams of same width and height into single video stream:
5890 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5894 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5896 [a0][a1]mergeplanes=0x00010210:yuva444p
5900 Swap Y and A plane in yuva444p stream:
5902 format=yuva444p,mergeplanes=0x03010200:yuva444p
5906 Swap U and V plane in yuv420p stream:
5908 format=yuv420p,mergeplanes=0x000201:yuv420p
5912 Cast a rgb24 clip to yuv444p:
5914 format=rgb24,mergeplanes=0x000102:yuv444p
5920 Apply motion-compensation deinterlacing.
5922 It needs one field per frame as input and must thus be used together
5923 with yadif=1/3 or equivalent.
5925 This filter accepts the following options:
5928 Set the deinterlacing mode.
5930 It accepts one of the following values:
5935 use iterative motion estimation
5937 like @samp{slow}, but use multiple reference frames.
5939 Default value is @samp{fast}.
5942 Set the picture field parity assumed for the input video. It must be
5943 one of the following values:
5947 assume top field first
5949 assume bottom field first
5952 Default value is @samp{bff}.
5955 Set per-block quantization parameter (QP) used by the internal
5958 Higher values should result in a smoother motion vector field but less
5959 optimal individual vectors. Default value is 1.
5964 Apply an MPlayer filter to the input video.
5966 This filter provides a wrapper around some of the filters of
5969 This wrapper is considered experimental. Some of the wrapped filters
5970 may not work properly and we may drop support for them, as they will
5971 be implemented natively into FFmpeg. Thus you should avoid
5972 depending on them when writing portable scripts.
5974 The filter accepts the parameters:
5975 @var{filter_name}[:=]@var{filter_params}
5977 @var{filter_name} is the name of a supported MPlayer filter,
5978 @var{filter_params} is a string containing the parameters accepted by
5981 The list of the currently supported filters follows:
5992 The parameter syntax and behavior for the listed filters are the same
5993 of the corresponding MPlayer filters. For detailed instructions check
5994 the "VIDEO FILTERS" section in the MPlayer manual.
5996 @subsection Examples
6000 Adjust gamma, brightness, contrast:
6006 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
6010 Drop frames that do not differ greatly from the previous frame in
6011 order to reduce frame rate.
6013 The main use of this filter is for very-low-bitrate encoding
6014 (e.g. streaming over dialup modem), but it could in theory be used for
6015 fixing movies that were inverse-telecined incorrectly.
6017 A description of the accepted options follows.
6021 Set the maximum number of consecutive frames which can be dropped (if
6022 positive), or the minimum interval between dropped frames (if
6023 negative). If the value is 0, the frame is dropped unregarding the
6024 number of previous sequentially dropped frames.
6031 Set the dropping threshold values.
6033 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
6034 represent actual pixel value differences, so a threshold of 64
6035 corresponds to 1 unit of difference for each pixel, or the same spread
6036 out differently over the block.
6038 A frame is a candidate for dropping if no 8x8 blocks differ by more
6039 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6040 meaning the whole image) differ by more than a threshold of @option{lo}.
6042 Default value for @option{hi} is 64*12, default value for @option{lo} is
6043 64*5, and default value for @option{frac} is 0.33.
6051 It accepts an integer in input; if non-zero it negates the
6052 alpha component (if available). The default value in input is 0.
6056 Force libavfilter not to use any of the specified pixel formats for the
6057 input to the next filter.
6059 It accepts the following parameters:
6063 A '|'-separated list of pixel format names, such as
6064 apix_fmts=yuv420p|monow|rgb24".
6068 @subsection Examples
6072 Force libavfilter to use a format different from @var{yuv420p} for the
6073 input to the vflip filter:
6075 noformat=pix_fmts=yuv420p,vflip
6079 Convert the input video to any of the formats not contained in the list:
6081 noformat=yuv420p|yuv444p|yuv410p
6087 Add noise on video input frame.
6089 The filter accepts the following options:
6097 Set noise seed for specific pixel component or all pixel components in case
6098 of @var{all_seed}. Default value is @code{123457}.
6100 @item all_strength, alls
6101 @item c0_strength, c0s
6102 @item c1_strength, c1s
6103 @item c2_strength, c2s
6104 @item c3_strength, c3s
6105 Set noise strength for specific pixel component or all pixel components in case
6106 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6108 @item all_flags, allf
6113 Set pixel component flags or set flags for all components if @var{all_flags}.
6114 Available values for component flags are:
6117 averaged temporal noise (smoother)
6119 mix random noise with a (semi)regular pattern
6121 temporal noise (noise pattern changes between frames)
6123 uniform noise (gaussian otherwise)
6127 @subsection Examples
6129 Add temporal and uniform noise to input video:
6131 noise=alls=20:allf=t+u
6136 Pass the video source unchanged to the output.
6140 Apply a video transform using libopencv.
6142 To enable this filter, install the libopencv library and headers and
6143 configure FFmpeg with @code{--enable-libopencv}.
6145 It accepts the following parameters:
6150 The name of the libopencv filter to apply.
6153 The parameters to pass to the libopencv filter. If not specified, the default
6158 Refer to the official libopencv documentation for more precise
6160 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
6162 Several libopencv filters are supported; see the following subsections.
6167 Dilate an image by using a specific structuring element.
6168 It corresponds to the libopencv function @code{cvDilate}.
6170 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6172 @var{struct_el} represents a structuring element, and has the syntax:
6173 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6175 @var{cols} and @var{rows} represent the number of columns and rows of
6176 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6177 point, and @var{shape} the shape for the structuring element. @var{shape}
6178 must be "rect", "cross", "ellipse", or "custom".
6180 If the value for @var{shape} is "custom", it must be followed by a
6181 string of the form "=@var{filename}". The file with name
6182 @var{filename} is assumed to represent a binary image, with each
6183 printable character corresponding to a bright pixel. When a custom
6184 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6185 or columns and rows of the read file are assumed instead.
6187 The default value for @var{struct_el} is "3x3+0x0/rect".
6189 @var{nb_iterations} specifies the number of times the transform is
6190 applied to the image, and defaults to 1.
6194 # Use the default values
6197 # Dilate using a structuring element with a 5x5 cross, iterating two times
6198 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6200 # Read the shape from the file diamond.shape, iterating two times.
6201 # The file diamond.shape may contain a pattern of characters like this
6207 # The specified columns and rows are ignored
6208 # but the anchor point coordinates are not
6209 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6214 Erode an image by using a specific structuring element.
6215 It corresponds to the libopencv function @code{cvErode}.
6217 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6218 with the same syntax and semantics as the @ref{dilate} filter.
6222 Smooth the input video.
6224 The filter takes the following parameters:
6225 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6227 @var{type} is the type of smooth filter to apply, and must be one of
6228 the following values: "blur", "blur_no_scale", "median", "gaussian",
6229 or "bilateral". The default value is "gaussian".
6231 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6232 depend on the smooth type. @var{param1} and
6233 @var{param2} accept integer positive values or 0. @var{param3} and
6234 @var{param4} accept floating point values.
6236 The default value for @var{param1} is 3. The default value for the
6237 other parameters is 0.
6239 These parameters correspond to the parameters assigned to the
6240 libopencv function @code{cvSmooth}.
6245 Overlay one video on top of another.
6247 It takes two inputs and has one output. The first input is the "main"
6248 video on which the second input is overlayed.
6250 It accepts the following parameters:
6252 A description of the accepted options follows.
6257 Set the expression for the x and y coordinates of the overlayed video
6258 on the main video. Default value is "0" for both expressions. In case
6259 the expression is invalid, it is set to a huge value (meaning that the
6260 overlay will not be displayed within the output visible area).
6263 The action to take when EOF is encountered on the secondary input; it accepts
6264 one of the following values:
6268 Repeat the last frame (the default).
6272 Pass the main input through.
6276 Set when the expressions for @option{x}, and @option{y} are evaluated.
6278 It accepts the following values:
6281 only evaluate expressions once during the filter initialization or
6282 when a command is processed
6285 evaluate expressions for each incoming frame
6288 Default value is @samp{frame}.
6291 If set to 1, force the output to terminate when the shortest input
6292 terminates. Default value is 0.
6295 Set the format for the output video.
6297 It accepts the following values:
6312 Default value is @samp{yuv420}.
6314 @item rgb @emph{(deprecated)}
6315 If set to 1, force the filter to accept inputs in the RGB
6316 color space. Default value is 0. This option is deprecated, use
6317 @option{format} instead.
6320 If set to 1, force the filter to draw the last overlay frame over the
6321 main input until the end of the stream. A value of 0 disables this
6322 behavior. Default value is 1.
6325 The @option{x}, and @option{y} expressions can contain the following
6331 The main input width and height.
6335 The overlay input width and height.
6339 The computed values for @var{x} and @var{y}. They are evaluated for
6344 horizontal and vertical chroma subsample values of the output
6345 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6349 the number of input frame, starting from 0
6352 the position in the file of the input frame, NAN if unknown
6355 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6359 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6360 when evaluation is done @emph{per frame}, and will evaluate to NAN
6361 when @option{eval} is set to @samp{init}.
6363 Be aware that frames are taken from each input video in timestamp
6364 order, hence, if their initial timestamps differ, it is a good idea
6365 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6366 have them begin in the same zero timestamp, as the example for
6367 the @var{movie} filter does.
6369 You can chain together more overlays but you should test the
6370 efficiency of such approach.
6372 @subsection Commands
6374 This filter supports the following commands:
6378 Modify the x and y of the overlay input.
6379 The command accepts the same syntax of the corresponding option.
6381 If the specified expression is not valid, it is kept at its current
6385 @subsection Examples
6389 Draw the overlay at 10 pixels from the bottom right corner of the main
6392 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6395 Using named options the example above becomes:
6397 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6401 Insert a transparent PNG logo in the bottom left corner of the input,
6402 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6404 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6408 Insert 2 different transparent PNG logos (second logo on bottom
6409 right corner) using the @command{ffmpeg} tool:
6411 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
6415 Add a transparent color layer on top of the main video; @code{WxH}
6416 must specify the size of the main input to the overlay filter:
6418 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6422 Play an original video and a filtered version (here with the deshake
6423 filter) side by side using the @command{ffplay} tool:
6425 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6428 The above command is the same as:
6430 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6434 Make a sliding overlay appearing from the left to the right top part of the
6435 screen starting since time 2:
6437 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6441 Compose output by putting two input videos side to side:
6443 ffmpeg -i left.avi -i right.avi -filter_complex "
6444 nullsrc=size=200x100 [background];
6445 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6446 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6447 [background][left] overlay=shortest=1 [background+left];
6448 [background+left][right] overlay=shortest=1:x=100 [left+right]
6453 Mask 10-20 seconds of a video by applying the delogo filter to a section
6455 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6456 -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]'
6461 Chain several overlays in cascade:
6463 nullsrc=s=200x200 [bg];
6464 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6465 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6466 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6467 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6468 [in3] null, [mid2] overlay=100:100 [out0]
6475 Apply Overcomplete Wavelet denoiser.
6477 The filter accepts the following options:
6483 Larger depth values will denoise lower frequency components more, but
6484 slow down filtering.
6486 Must be an int in the range 8-16, default is @code{8}.
6488 @item luma_strength, ls
6491 Must be a double value in the range 0-1000, default is @code{1.0}.
6493 @item chroma_strength, cs
6494 Set chroma strength.
6496 Must be a double value in the range 0-1000, default is @code{1.0}.
6501 Add paddings to the input image, and place the original input at the
6502 provided @var{x}, @var{y} coordinates.
6504 It accepts the following parameters:
6509 Specify an expression for the size of the output image with the
6510 paddings added. If the value for @var{width} or @var{height} is 0, the
6511 corresponding input size is used for the output.
6513 The @var{width} expression can reference the value set by the
6514 @var{height} expression, and vice versa.
6516 The default value of @var{width} and @var{height} is 0.
6520 Specify the offsets to place the input image at within the padded area,
6521 with respect to the top/left border of the output image.
6523 The @var{x} expression can reference the value set by the @var{y}
6524 expression, and vice versa.
6526 The default value of @var{x} and @var{y} is 0.
6529 Specify the color of the padded area. For the syntax of this option,
6530 check the "Color" section in the ffmpeg-utils manual.
6532 The default value of @var{color} is "black".
6535 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6536 options are expressions containing the following constants:
6541 The input video width and height.
6545 These are the same as @var{in_w} and @var{in_h}.
6549 The output width and height (the size of the padded area), as
6550 specified by the @var{width} and @var{height} expressions.
6554 These are the same as @var{out_w} and @var{out_h}.
6558 The x and y offsets as specified by the @var{x} and @var{y}
6559 expressions, or NAN if not yet specified.
6562 same as @var{iw} / @var{ih}
6565 input sample aspect ratio
6568 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6572 The horizontal and vertical chroma subsample values. For example for the
6573 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6576 @subsection Examples
6580 Add paddings with the color "violet" to the input video. The output video
6581 size is 640x480, and the top-left corner of the input video is placed at
6584 pad=640:480:0:40:violet
6587 The example above is equivalent to the following command:
6589 pad=width=640:height=480:x=0:y=40:color=violet
6593 Pad the input to get an output with dimensions increased by 3/2,
6594 and put the input video at the center of the padded area:
6596 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6600 Pad the input to get a squared output with size equal to the maximum
6601 value between the input width and height, and put the input video at
6602 the center of the padded area:
6604 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6608 Pad the input to get a final w/h ratio of 16:9:
6610 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6614 In case of anamorphic video, in order to set the output display aspect
6615 correctly, it is necessary to use @var{sar} in the expression,
6616 according to the relation:
6618 (ih * X / ih) * sar = output_dar
6619 X = output_dar / sar
6622 Thus the previous example needs to be modified to:
6624 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6628 Double the output size and put the input video in the bottom-right
6629 corner of the output padded area:
6631 pad="2*iw:2*ih:ow-iw:oh-ih"
6635 @section perspective
6637 Correct perspective of video not recorded perpendicular to the screen.
6639 A description of the accepted parameters follows.
6650 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6651 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6653 The expressions can use the following variables:
6658 the width and height of video frame.
6662 Set interpolation for perspective correction.
6664 It accepts the following values:
6670 Default value is @samp{linear}.
6675 Delay interlaced video by one field time so that the field order changes.
6677 The intended use is to fix PAL movies that have been captured with the
6678 opposite field order to the film-to-video transfer.
6680 A description of the accepted parameters follows.
6686 It accepts the following values:
6689 Capture field order top-first, transfer bottom-first.
6690 Filter will delay the bottom field.
6693 Capture field order bottom-first, transfer top-first.
6694 Filter will delay the top field.
6697 Capture and transfer with the same field order. This mode only exists
6698 for the documentation of the other options to refer to, but if you
6699 actually select it, the filter will faithfully do nothing.
6702 Capture field order determined automatically by field flags, transfer
6704 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6705 basis using field flags. If no field information is available,
6706 then this works just like @samp{u}.
6709 Capture unknown or varying, transfer opposite.
6710 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6711 analyzing the images and selecting the alternative that produces best
6712 match between the fields.
6715 Capture top-first, transfer unknown or varying.
6716 Filter selects among @samp{t} and @samp{p} using image analysis.
6719 Capture bottom-first, transfer unknown or varying.
6720 Filter selects among @samp{b} and @samp{p} using image analysis.
6723 Capture determined by field flags, transfer unknown or varying.
6724 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6725 image analysis. If no field information is available, then this works just
6726 like @samp{U}. This is the default mode.
6729 Both capture and transfer unknown or varying.
6730 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6734 @section pixdesctest
6736 Pixel format descriptor test filter, mainly useful for internal
6737 testing. The output video should be equal to the input video.
6741 format=monow, pixdesctest
6744 can be used to test the monowhite pixel format descriptor definition.
6748 Enable the specified chain of postprocessing subfilters using libpostproc. This
6749 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6750 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6751 Each subfilter and some options have a short and a long name that can be used
6752 interchangeably, i.e. dr/dering are the same.
6754 The filters accept the following options:
6758 Set postprocessing subfilters string.
6761 All subfilters share common options to determine their scope:
6765 Honor the quality commands for this subfilter.
6768 Do chrominance filtering, too (default).
6771 Do luminance filtering only (no chrominance).
6774 Do chrominance filtering only (no luminance).
6777 These options can be appended after the subfilter name, separated by a '|'.
6779 Available subfilters are:
6782 @item hb/hdeblock[|difference[|flatness]]
6783 Horizontal deblocking filter
6786 Difference factor where higher values mean more deblocking (default: @code{32}).
6788 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6791 @item vb/vdeblock[|difference[|flatness]]
6792 Vertical deblocking filter
6795 Difference factor where higher values mean more deblocking (default: @code{32}).
6797 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6800 @item ha/hadeblock[|difference[|flatness]]
6801 Accurate horizontal deblocking filter
6804 Difference factor where higher values mean more deblocking (default: @code{32}).
6806 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6809 @item va/vadeblock[|difference[|flatness]]
6810 Accurate vertical deblocking filter
6813 Difference factor where higher values mean more deblocking (default: @code{32}).
6815 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6819 The horizontal and vertical deblocking filters share the difference and
6820 flatness values so you cannot set different horizontal and vertical
6825 Experimental horizontal deblocking filter
6828 Experimental vertical deblocking filter
6833 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6836 larger -> stronger filtering
6838 larger -> stronger filtering
6840 larger -> stronger filtering
6843 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6846 Stretch luminance to @code{0-255}.
6849 @item lb/linblenddeint
6850 Linear blend deinterlacing filter that deinterlaces the given block by
6851 filtering all lines with a @code{(1 2 1)} filter.
6853 @item li/linipoldeint
6854 Linear interpolating deinterlacing filter that deinterlaces the given block by
6855 linearly interpolating every second line.
6857 @item ci/cubicipoldeint
6858 Cubic interpolating deinterlacing filter deinterlaces the given block by
6859 cubically interpolating every second line.
6861 @item md/mediandeint
6862 Median deinterlacing filter that deinterlaces the given block by applying a
6863 median filter to every second line.
6865 @item fd/ffmpegdeint
6866 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6867 second line with a @code{(-1 4 2 4 -1)} filter.
6870 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6871 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6873 @item fq/forceQuant[|quantizer]
6874 Overrides the quantizer table from the input with the constant quantizer you
6882 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6885 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6888 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6891 @subsection Examples
6895 Apply horizontal and vertical deblocking, deringing and automatic
6896 brightness/contrast:
6902 Apply default filters without brightness/contrast correction:
6908 Apply default filters and temporal denoiser:
6910 pp=default/tmpnoise|1|2|3
6914 Apply deblocking on luminance only, and switch vertical deblocking on or off
6915 automatically depending on available CPU time:
6923 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6924 Ratio) between two input videos.
6926 This filter takes in input two input videos, the first input is
6927 considered the "main" source and is passed unchanged to the
6928 output. The second input is used as a "reference" video for computing
6931 Both video inputs must have the same resolution and pixel format for
6932 this filter to work correctly. Also it assumes that both inputs
6933 have the same number of frames, which are compared one by one.
6935 The obtained average PSNR is printed through the logging system.
6937 The filter stores the accumulated MSE (mean squared error) of each
6938 frame, and at the end of the processing it is averaged across all frames
6939 equally, and the following formula is applied to obtain the PSNR:
6942 PSNR = 10*log10(MAX^2/MSE)
6945 Where MAX is the average of the maximum values of each component of the
6948 The description of the accepted parameters follows.
6952 If specified the filter will use the named file to save the PSNR of
6953 each individual frame.
6956 The file printed if @var{stats_file} is selected, contains a sequence of
6957 key/value pairs of the form @var{key}:@var{value} for each compared
6960 A description of each shown parameter follows:
6964 sequential number of the input frame, starting from 1
6967 Mean Square Error pixel-by-pixel average difference of the compared
6968 frames, averaged over all the image components.
6970 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6971 Mean Square Error pixel-by-pixel average difference of the compared
6972 frames for the component specified by the suffix.
6974 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6975 Peak Signal to Noise ratio of the compared frames for the component
6976 specified by the suffix.
6981 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6982 [main][ref] psnr="stats_file=stats.log" [out]
6985 On this example the input file being processed is compared with the
6986 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6987 is stored in @file{stats.log}.
6992 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6993 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6996 The pullup filter is designed to take advantage of future context in making
6997 its decisions. This filter is stateless in the sense that it does not lock
6998 onto a pattern to follow, but it instead looks forward to the following
6999 fields in order to identify matches and rebuild progressive frames.
7001 To produce content with an even framerate, insert the fps filter after
7002 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
7003 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
7005 The filter accepts the following options:
7012 These options set the amount of "junk" to ignore at the left, right, top, and
7013 bottom of the image, respectively. Left and right are in units of 8 pixels,
7014 while top and bottom are in units of 2 lines.
7015 The default is 8 pixels on each side.
7018 Set the strict breaks. Setting this option to 1 will reduce the chances of
7019 filter generating an occasional mismatched frame, but it may also cause an
7020 excessive number of frames to be dropped during high motion sequences.
7021 Conversely, setting it to -1 will make filter match fields more easily.
7022 This may help processing of video where there is slight blurring between
7023 the fields, but may also cause there to be interlaced frames in the output.
7024 Default value is @code{0}.
7027 Set the metric plane to use. It accepts the following values:
7033 Use chroma blue plane.
7036 Use chroma red plane.
7039 This option may be set to use chroma plane instead of the default luma plane
7040 for doing filter's computations. This may improve accuracy on very clean
7041 source material, but more likely will decrease accuracy, especially if there
7042 is chroma noise (rainbow effect) or any grayscale video.
7043 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7044 load and make pullup usable in realtime on slow machines.
7047 For best results (without duplicated frames in the output file) it is
7048 necessary to change the output frame rate. For example, to inverse
7049 telecine NTSC input:
7051 ffmpeg -i input -vf pullup -r 24000/1001 ...
7056 Suppress a TV station logo, using an image file to determine which
7057 pixels comprise the logo. It works by filling in the pixels that
7058 comprise the logo with neighboring pixels.
7060 The filter accepts the following options:
7064 Set the filter bitmap file, which can be any image format supported by
7065 libavformat. The width and height of the image file must match those of the
7066 video stream being processed.
7069 Pixels in the provided bitmap image with a value of zero are not
7070 considered part of the logo, non-zero pixels are considered part of
7071 the logo. If you use white (255) for the logo and black (0) for the
7072 rest, you will be safe. For making the filter bitmap, it is
7073 recommended to take a screen capture of a black frame with the logo
7074 visible, and then using a threshold filter followed by the erode
7075 filter once or twice.
7077 If needed, little splotches can be fixed manually. Remember that if
7078 logo pixels are not covered, the filter quality will be much
7079 reduced. Marking too many pixels as part of the logo does not hurt as
7080 much, but it will increase the amount of blurring needed to cover over
7081 the image and will destroy more information than necessary, and extra
7082 pixels will slow things down on a large logo.
7086 Rotate video by an arbitrary angle expressed in radians.
7088 The filter accepts the following options:
7090 A description of the optional parameters follows.
7093 Set an expression for the angle by which to rotate the input video
7094 clockwise, expressed as a number of radians. A negative value will
7095 result in a counter-clockwise rotation. By default it is set to "0".
7097 This expression is evaluated for each frame.
7100 Set the output width expression, default value is "iw".
7101 This expression is evaluated just once during configuration.
7104 Set the output height expression, default value is "ih".
7105 This expression is evaluated just once during configuration.
7108 Enable bilinear interpolation if set to 1, a value of 0 disables
7109 it. Default value is 1.
7112 Set the color used to fill the output area not covered by the rotated
7113 image. For the generalsyntax of this option, check the "Color" section in the
7114 ffmpeg-utils manual. If the special value "none" is selected then no
7115 background is printed (useful for example if the background is never shown).
7117 Default value is "black".
7120 The expressions for the angle and the output size can contain the
7121 following constants and functions:
7125 sequential number of the input frame, starting from 0. It is always NAN
7126 before the first frame is filtered.
7129 time in seconds of the input frame, it is set to 0 when the filter is
7130 configured. It is always NAN before the first frame is filtered.
7134 horizontal and vertical chroma subsample values. For example for the
7135 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7139 the input video width and height
7143 the output width and height, that is the size of the padded area as
7144 specified by the @var{width} and @var{height} expressions
7148 the minimal width/height required for completely containing the input
7149 video rotated by @var{a} radians.
7151 These are only available when computing the @option{out_w} and
7152 @option{out_h} expressions.
7155 @subsection Examples
7159 Rotate the input by PI/6 radians clockwise:
7165 Rotate the input by PI/6 radians counter-clockwise:
7171 Rotate the input by 45 degrees clockwise:
7177 Apply a constant rotation with period T, starting from an angle of PI/3:
7179 rotate=PI/3+2*PI*t/T
7183 Make the input video rotation oscillating with a period of T
7184 seconds and an amplitude of A radians:
7186 rotate=A*sin(2*PI/T*t)
7190 Rotate the video, output size is chosen so that the whole rotating
7191 input video is always completely contained in the output:
7193 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7197 Rotate the video, reduce the output size so that no background is ever
7200 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7204 @subsection Commands
7206 The filter supports the following commands:
7210 Set the angle expression.
7211 The command accepts the same syntax of the corresponding option.
7213 If the specified expression is not valid, it is kept at its current
7219 Apply Shape Adaptive Blur.
7221 The filter accepts the following options:
7224 @item luma_radius, lr
7225 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7226 value is 1.0. A greater value will result in a more blurred image, and
7227 in slower processing.
7229 @item luma_pre_filter_radius, lpfr
7230 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7233 @item luma_strength, ls
7234 Set luma maximum difference between pixels to still be considered, must
7235 be a value in the 0.1-100.0 range, default value is 1.0.
7237 @item chroma_radius, cr
7238 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7239 greater value will result in a more blurred image, and in slower
7242 @item chroma_pre_filter_radius, cpfr
7243 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7245 @item chroma_strength, cs
7246 Set chroma maximum difference between pixels to still be considered,
7247 must be a value in the 0.1-100.0 range.
7250 Each chroma option value, if not explicitly specified, is set to the
7251 corresponding luma option value.
7256 Scale (resize) the input video, using the libswscale library.
7258 The scale filter forces the output display aspect ratio to be the same
7259 of the input, by changing the output sample aspect ratio.
7261 If the input image format is different from the format requested by
7262 the next filter, the scale filter will convert the input to the
7266 The filter accepts the following options, or any of the options
7267 supported by the libswscale scaler.
7269 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7270 the complete list of scaler options.
7275 Set the output video dimension expression. Default value is the input
7278 If the value is 0, the input width is used for the output.
7280 If one of the values is -1, the scale filter will use a value that
7281 maintains the aspect ratio of the input image, calculated from the
7282 other specified dimension. If both of them are -1, the input size is
7285 If one of the values is -n with n > 1, the scale filter will also use a value
7286 that maintains the aspect ratio of the input image, calculated from the other
7287 specified dimension. After that it will, however, make sure that the calculated
7288 dimension is divisible by n and adjust the value if necessary.
7290 See below for the list of accepted constants for use in the dimension
7294 Set the interlacing mode. It accepts the following values:
7298 Force interlaced aware scaling.
7301 Do not apply interlaced scaling.
7304 Select interlaced aware scaling depending on whether the source frames
7305 are flagged as interlaced or not.
7308 Default value is @samp{0}.
7311 Set libswscale scaling flags. See
7312 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7313 complete list of values. If not explicitly specified the filter applies
7317 Set the video size. For the syntax of this option, check the "Video size"
7318 section in the ffmpeg-utils manual.
7320 @item in_color_matrix
7321 @item out_color_matrix
7322 Set in/output YCbCr color space type.
7324 This allows the autodetected value to be overridden as well as allows forcing
7325 a specific value used for the output and encoder.
7327 If not specified, the color space type depends on the pixel format.
7333 Choose automatically.
7336 Format conforming to International Telecommunication Union (ITU)
7337 Recommendation BT.709.
7340 Set color space conforming to the United States Federal Communications
7341 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7344 Set color space conforming to:
7348 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7351 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7354 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7359 Set color space conforming to SMPTE ST 240:1999.
7364 Set in/output YCbCr sample range.
7366 This allows the autodetected value to be overridden as well as allows forcing
7367 a specific value used for the output and encoder. If not specified, the
7368 range depends on the pixel format. Possible values:
7372 Choose automatically.
7375 Set full range (0-255 in case of 8-bit luma).
7378 Set "MPEG" range (16-235 in case of 8-bit luma).
7381 @item force_original_aspect_ratio
7382 Enable decreasing or increasing output video width or height if necessary to
7383 keep the original aspect ratio. Possible values:
7387 Scale the video as specified and disable this feature.
7390 The output video dimensions will automatically be decreased if needed.
7393 The output video dimensions will automatically be increased if needed.
7397 One useful instance of this option is that when you know a specific device's
7398 maximum allowed resolution, you can use this to limit the output video to
7399 that, while retaining the aspect ratio. For example, device A allows
7400 1280x720 playback, and your video is 1920x800. Using this option (set it to
7401 decrease) and specifying 1280x720 to the command line makes the output
7404 Please note that this is a different thing than specifying -1 for @option{w}
7405 or @option{h}, you still need to specify the output resolution for this option
7410 The values of the @option{w} and @option{h} options are expressions
7411 containing the following constants:
7416 The input width and height
7420 These are the same as @var{in_w} and @var{in_h}.
7424 The output (scaled) width and height
7428 These are the same as @var{out_w} and @var{out_h}
7431 The same as @var{iw} / @var{ih}
7434 input sample aspect ratio
7437 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7441 horizontal and vertical input chroma subsample values. For example for the
7442 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7446 horizontal and vertical output chroma subsample values. For example for the
7447 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7450 @subsection Examples
7454 Scale the input video to a size of 200x100
7459 This is equivalent to:
7470 Specify a size abbreviation for the output size:
7475 which can also be written as:
7481 Scale the input to 2x:
7487 The above is the same as:
7493 Scale the input to 2x with forced interlaced scaling:
7495 scale=2*iw:2*ih:interl=1
7499 Scale the input to half size:
7505 Increase the width, and set the height to the same size:
7518 Increase the height, and set the width to 3/2 of the height:
7520 scale=w=3/2*oh:h=3/5*ih
7524 Increase the size, making the size a multiple of the chroma
7527 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7531 Increase the width to a maximum of 500 pixels,
7532 keeping the same aspect ratio as the input:
7534 scale=w='min(500\, iw*3/2):h=-1'
7538 @section separatefields
7540 The @code{separatefields} takes a frame-based video input and splits
7541 each frame into its components fields, producing a new half height clip
7542 with twice the frame rate and twice the frame count.
7544 This filter use field-dominance information in frame to decide which
7545 of each pair of fields to place first in the output.
7546 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7548 @section setdar, setsar
7550 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7553 This is done by changing the specified Sample (aka Pixel) Aspect
7554 Ratio, according to the following equation:
7556 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7559 Keep in mind that the @code{setdar} filter does not modify the pixel
7560 dimensions of the video frame. Also, the display aspect ratio set by
7561 this filter may be changed by later filters in the filterchain,
7562 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7565 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7566 the filter output video.
7568 Note that as a consequence of the application of this filter, the
7569 output display aspect ratio will change according to the equation
7572 Keep in mind that the sample aspect ratio set by the @code{setsar}
7573 filter may be changed by later filters in the filterchain, e.g. if
7574 another "setsar" or a "setdar" filter is applied.
7576 It accepts the following parameters:
7579 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7580 Set the aspect ratio used by the filter.
7582 The parameter can be a floating point number string, an expression, or
7583 a string of the form @var{num}:@var{den}, where @var{num} and
7584 @var{den} are the numerator and denominator of the aspect ratio. If
7585 the parameter is not specified, it is assumed the value "0".
7586 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7590 Set the maximum integer value to use for expressing numerator and
7591 denominator when reducing the expressed aspect ratio to a rational.
7592 Default value is @code{100}.
7596 The parameter @var{sar} is an expression containing
7597 the following constants:
7601 These are approximated values for the mathematical constants e
7602 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7605 The input width and height.
7608 These are the same as @var{w} / @var{h}.
7611 The input sample aspect ratio.
7614 The input display aspect ratio. It is the same as
7615 (@var{w} / @var{h}) * @var{sar}.
7618 Horizontal and vertical chroma subsample values. For example, for the
7619 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7622 @subsection Examples
7627 To change the display aspect ratio to 16:9, specify one of the following:
7635 To change the sample aspect ratio to 10:11, specify:
7641 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7642 1000 in the aspect ratio reduction, use the command:
7644 setdar=ratio=16/9:max=1000
7652 Force field for the output video frame.
7654 The @code{setfield} filter marks the interlace type field for the
7655 output frames. It does not change the input frame, but only sets the
7656 corresponding property, which affects how the frame is treated by
7657 following filters (e.g. @code{fieldorder} or @code{yadif}).
7659 The filter accepts the following options:
7664 Available values are:
7668 Keep the same field property.
7671 Mark the frame as bottom-field-first.
7674 Mark the frame as top-field-first.
7677 Mark the frame as progressive.
7683 Show a line containing various information for each input video frame.
7684 The input video is not modified.
7686 The shown line contains a sequence of key/value pairs of the form
7687 @var{key}:@var{value}.
7689 The following values are shown in the output:
7693 The (sequential) number of the input frame, starting from 0.
7696 The Presentation TimeStamp of the input frame, expressed as a number of
7697 time base units. The time base unit depends on the filter input pad.
7700 The Presentation TimeStamp of the input frame, expressed as a number of
7704 The position of the frame in the input stream, or -1 if this information is
7705 unavailable and/or meaningless (for example in case of synthetic video).
7708 The pixel format name.
7711 The sample aspect ratio of the input frame, expressed in the form
7712 @var{num}/@var{den}.
7715 The size of the input frame. For the syntax of this option, check the "Video size"
7716 section in the ffmpeg-utils manual.
7719 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7720 for bottom field first).
7723 This is 1 if the frame is a key frame, 0 otherwise.
7726 The picture type of the input frame ("I" for an I-frame, "P" for a
7727 P-frame, "B" for a B-frame, or "?" for an unknown type).
7728 Also refer to the documentation of the @code{AVPictureType} enum and of
7729 the @code{av_get_picture_type_char} function defined in
7730 @file{libavutil/avutil.h}.
7733 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7735 @item plane_checksum
7736 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7737 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7740 @section shuffleplanes
7742 Reorder and/or duplicate video planes.
7744 It accepts the following parameters:
7749 The index of the input plane to be used as the first output plane.
7752 The index of the input plane to be used as the second output plane.
7755 The index of the input plane to be used as the third output plane.
7758 The index of the input plane to be used as the fourth output plane.
7762 The first plane has the index 0. The default is to keep the input unchanged.
7764 Swap the second and third planes of the input:
7766 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7769 @section signalstats
7770 Evaluate various visual metrics that assist in determining issues associated
7771 with the digitization of analog video media.
7773 By default the filter will log these metadata values:
7777 Display the minimal Y value contained within the input frame. Expressed in
7781 Display the Y value at the 10% percentile within the input frame. Expressed in
7785 Display the average Y value within the input frame. Expressed in range of
7789 Display the Y value at the 90% percentile within the input frame. Expressed in
7793 Display the maximum Y value contained within the input frame. Expressed in
7797 Display the minimal U value contained within the input frame. Expressed in
7801 Display the U value at the 10% percentile within the input frame. Expressed in
7805 Display the average U value within the input frame. Expressed in range of
7809 Display the U value at the 90% percentile within the input frame. Expressed in
7813 Display the maximum U value contained within the input frame. Expressed in
7817 Display the minimal V value contained within the input frame. Expressed in
7821 Display the V value at the 10% percentile within the input frame. Expressed in
7825 Display the average V value within the input frame. Expressed in range of
7829 Display the V value at the 90% percentile within the input frame. Expressed in
7833 Display the maximum V value contained within the input frame. Expressed in
7837 Display the minimal saturation value contained within the input frame.
7838 Expressed in range of [0-~181.02].
7841 Display the saturation value at the 10% percentile within the input frame.
7842 Expressed in range of [0-~181.02].
7845 Display the average saturation value within the input frame. Expressed in range
7849 Display the saturation value at the 90% percentile within the input frame.
7850 Expressed in range of [0-~181.02].
7853 Display the maximum saturation value contained within the input frame.
7854 Expressed in range of [0-~181.02].
7857 Display the median value for hue within the input frame. Expressed in range of
7861 Display the average value for hue within the input frame. Expressed in range of
7865 Display the average of sample value difference between all values of the Y
7866 plane in the current frame and corresponding values of the previous input frame.
7867 Expressed in range of [0-255].
7870 Display the average of sample value difference between all values of the U
7871 plane in the current frame and corresponding values of the previous input frame.
7872 Expressed in range of [0-255].
7875 Display the average of sample value difference between all values of the V
7876 plane in the current frame and corresponding values of the previous input frame.
7877 Expressed in range of [0-255].
7880 The filter accepts the following options:
7886 @option{stat} specify an additional form of image analysis.
7887 @option{out} output video with the specified type of pixel highlighted.
7889 Both options accept the following values:
7893 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
7894 unlike the neighboring pixels of the same field. Examples of temporal outliers
7895 include the results of video dropouts, head clogs, or tape tracking issues.
7898 Identify @var{vertical line repetition}. Vertical line repetition includes
7899 similar rows of pixels within a frame. In born-digital video vertical line
7900 repetition is common, but this pattern is uncommon in video digitized from an
7901 analog source. When it occurs in video that results from the digitization of an
7902 analog source it can indicate concealment from a dropout compensator.
7905 Identify pixels that fall outside of legal broadcast range.
7909 Set the highlight color for the @option{out} option. The default color is
7913 @subsection Examples
7917 Output data of various video metrics:
7919 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
7923 Output specific data about the minimum and maximum values of the Y plane per frame:
7925 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
7929 Playback video while highlighting pixels that are outside of broadcast range in red.
7931 ffplay example.mov -vf signalstats="out=brng:color=red"
7935 Playback video with signalstats metadata drawn over the frame.
7937 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
7940 The contents of signalstat_drawtext.txt used in the command are:
7943 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
7944 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
7945 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
7946 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
7954 Blur the input video without impacting the outlines.
7956 It accepts the following options:
7959 @item luma_radius, lr
7960 Set the luma radius. The option value must be a float number in
7961 the range [0.1,5.0] that specifies the variance of the gaussian filter
7962 used to blur the image (slower if larger). Default value is 1.0.
7964 @item luma_strength, ls
7965 Set the luma strength. The option value must be a float number
7966 in the range [-1.0,1.0] that configures the blurring. A value included
7967 in [0.0,1.0] will blur the image whereas a value included in
7968 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7970 @item luma_threshold, lt
7971 Set the luma threshold used as a coefficient to determine
7972 whether a pixel should be blurred or not. The option value must be an
7973 integer in the range [-30,30]. A value of 0 will filter all the image,
7974 a value included in [0,30] will filter flat areas and a value included
7975 in [-30,0] will filter edges. Default value is 0.
7977 @item chroma_radius, cr
7978 Set the chroma radius. The option value must be a float number in
7979 the range [0.1,5.0] that specifies the variance of the gaussian filter
7980 used to blur the image (slower if larger). Default value is 1.0.
7982 @item chroma_strength, cs
7983 Set the chroma strength. The option value must be a float number
7984 in the range [-1.0,1.0] that configures the blurring. A value included
7985 in [0.0,1.0] will blur the image whereas a value included in
7986 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7988 @item chroma_threshold, ct
7989 Set the chroma threshold used as a coefficient to determine
7990 whether a pixel should be blurred or not. The option value must be an
7991 integer in the range [-30,30]. A value of 0 will filter all the image,
7992 a value included in [0,30] will filter flat areas and a value included
7993 in [-30,0] will filter edges. Default value is 0.
7996 If a chroma option is not explicitly set, the corresponding luma value
8001 Convert between different stereoscopic image formats.
8003 The filters accept the following options:
8007 Set stereoscopic image format of input.
8009 Available values for input image formats are:
8012 side by side parallel (left eye left, right eye right)
8015 side by side crosseye (right eye left, left eye right)
8018 side by side parallel with half width resolution
8019 (left eye left, right eye right)
8022 side by side crosseye with half width resolution
8023 (right eye left, left eye right)
8026 above-below (left eye above, right eye below)
8029 above-below (right eye above, left eye below)
8032 above-below with half height resolution
8033 (left eye above, right eye below)
8036 above-below with half height resolution
8037 (right eye above, left eye below)
8040 alternating frames (left eye first, right eye second)
8043 alternating frames (right eye first, left eye second)
8045 Default value is @samp{sbsl}.
8049 Set stereoscopic image format of output.
8051 Available values for output image formats are all the input formats as well as:
8054 anaglyph red/blue gray
8055 (red filter on left eye, blue filter on right eye)
8058 anaglyph red/green gray
8059 (red filter on left eye, green filter on right eye)
8062 anaglyph red/cyan gray
8063 (red filter on left eye, cyan filter on right eye)
8066 anaglyph red/cyan half colored
8067 (red filter on left eye, cyan filter on right eye)
8070 anaglyph red/cyan color
8071 (red filter on left eye, cyan filter on right eye)
8074 anaglyph red/cyan color optimized with the least squares projection of dubois
8075 (red filter on left eye, cyan filter on right eye)
8078 anaglyph green/magenta gray
8079 (green filter on left eye, magenta filter on right eye)
8082 anaglyph green/magenta half colored
8083 (green filter on left eye, magenta filter on right eye)
8086 anaglyph green/magenta colored
8087 (green filter on left eye, magenta filter on right eye)
8090 anaglyph green/magenta color optimized with the least squares projection of dubois
8091 (green filter on left eye, magenta filter on right eye)
8094 anaglyph yellow/blue gray
8095 (yellow filter on left eye, blue filter on right eye)
8098 anaglyph yellow/blue half colored
8099 (yellow filter on left eye, blue filter on right eye)
8102 anaglyph yellow/blue colored
8103 (yellow filter on left eye, blue filter on right eye)
8106 anaglyph yellow/blue color optimized with the least squares projection of dubois
8107 (yellow filter on left eye, blue filter on right eye)
8110 interleaved rows (left eye has top row, right eye starts on next row)
8113 interleaved rows (right eye has top row, left eye starts on next row)
8116 mono output (left eye only)
8119 mono output (right eye only)
8122 Default value is @samp{arcd}.
8125 @subsection Examples
8129 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8135 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8143 Apply a simple postprocessing filter that compresses and decompresses the image
8144 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8145 and average the results.
8147 The filter accepts the following options:
8151 Set quality. This option defines the number of levels for averaging. It accepts
8152 an integer in the range 0-6. If set to @code{0}, the filter will have no
8153 effect. A value of @code{6} means the higher quality. For each increment of
8154 that value the speed drops by a factor of approximately 2. Default value is
8158 Force a constant quantization parameter. If not set, the filter will use the QP
8159 from the video stream (if available).
8162 Set thresholding mode. Available modes are:
8166 Set hard thresholding (default).
8168 Set soft thresholding (better de-ringing effect, but likely blurrier).
8172 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8173 option may cause flicker since the B-Frames have often larger QP. Default is
8174 @code{0} (not enabled).
8180 Draw subtitles on top of input video using the libass library.
8182 To enable compilation of this filter you need to configure FFmpeg with
8183 @code{--enable-libass}. This filter also requires a build with libavcodec and
8184 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8185 Alpha) subtitles format.
8187 The filter accepts the following options:
8191 Set the filename of the subtitle file to read. It must be specified.
8194 Specify the size of the original video, the video for which the ASS file
8195 was composed. For the syntax of this option, check the "Video size" section in
8196 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8197 this is necessary to correctly scale the fonts if the aspect ratio has been
8201 Set subtitles input character encoding. @code{subtitles} filter only. Only
8202 useful if not UTF-8.
8204 @item stream_index, si
8205 Set subtitles stream index. @code{subtitles} filter only.
8208 If the first key is not specified, it is assumed that the first value
8209 specifies the @option{filename}.
8211 For example, to render the file @file{sub.srt} on top of the input
8212 video, use the command:
8217 which is equivalent to:
8219 subtitles=filename=sub.srt
8222 To render the default subtitles stream from file @file{video.mkv}, use:
8227 To render the second subtitles stream from that file, use:
8229 subtitles=video.mkv:si=1
8234 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8235 Interpolate) pixel art scaling algorithm.
8237 Useful for enlarging pixel art images without reducing sharpness.
8244 Apply telecine process to the video.
8246 This filter accepts the following options:
8255 The default value is @code{top}.
8259 A string of numbers representing the pulldown pattern you wish to apply.
8260 The default value is @code{23}.
8264 Some typical patterns:
8269 24p: 2332 (preferred)
8276 24p: 222222222223 ("Euro pulldown")
8282 Select the most representative frame in a given sequence of consecutive frames.
8284 The filter accepts the following options:
8288 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8289 will pick one of them, and then handle the next batch of @var{n} frames until
8290 the end. Default is @code{100}.
8293 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8294 value will result in a higher memory usage, so a high value is not recommended.
8296 @subsection Examples
8300 Extract one picture each 50 frames:
8306 Complete example of a thumbnail creation with @command{ffmpeg}:
8308 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8314 Tile several successive frames together.
8316 The filter accepts the following options:
8321 Set the grid size (i.e. the number of lines and columns). For the syntax of
8322 this option, check the "Video size" section in the ffmpeg-utils manual.
8325 Set the maximum number of frames to render in the given area. It must be less
8326 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8327 the area will be used.
8330 Set the outer border margin in pixels.
8333 Set the inner border thickness (i.e. the number of pixels between frames). For
8334 more advanced padding options (such as having different values for the edges),
8335 refer to the pad video filter.
8338 Specify the color of the unused areaFor the syntax of this option, check the
8339 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8343 @subsection Examples
8347 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8349 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8351 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8352 duplicating each output frame to accommodate the originally detected frame
8356 Display @code{5} pictures in an area of @code{3x2} frames,
8357 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8358 mixed flat and named options:
8360 tile=3x2:nb_frames=5:padding=7:margin=2
8366 Perform various types of temporal field interlacing.
8368 Frames are counted starting from 1, so the first input frame is
8371 The filter accepts the following options:
8376 Specify the mode of the interlacing. This option can also be specified
8377 as a value alone. See below for a list of values for this option.
8379 Available values are:
8383 Move odd frames into the upper field, even into the lower field,
8384 generating a double height frame at half frame rate.
8387 Only output even frames, odd frames are dropped, generating a frame with
8388 unchanged height at half frame rate.
8391 Only output odd frames, even frames are dropped, generating a frame with
8392 unchanged height at half frame rate.
8395 Expand each frame to full height, but pad alternate lines with black,
8396 generating a frame with double height at the same input frame rate.
8398 @item interleave_top, 4
8399 Interleave the upper field from odd frames with the lower field from
8400 even frames, generating a frame with unchanged height at half frame rate.
8402 @item interleave_bottom, 5
8403 Interleave the lower field from odd frames with the upper field from
8404 even frames, generating a frame with unchanged height at half frame rate.
8406 @item interlacex2, 6
8407 Double frame rate with unchanged height. Frames are inserted each
8408 containing the second temporal field from the previous input frame and
8409 the first temporal field from the next input frame. This mode relies on
8410 the top_field_first flag. Useful for interlaced video displays with no
8411 field synchronisation.
8414 Numeric values are deprecated but are accepted for backward
8415 compatibility reasons.
8417 Default mode is @code{merge}.
8420 Specify flags influencing the filter process.
8422 Available value for @var{flags} is:
8425 @item low_pass_filter, vlfp
8426 Enable vertical low-pass filtering in the filter.
8427 Vertical low-pass filtering is required when creating an interlaced
8428 destination from a progressive source which contains high-frequency
8429 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8432 Vertical low-pass filtering can only be enabled for @option{mode}
8433 @var{interleave_top} and @var{interleave_bottom}.
8440 Transpose rows with columns in the input video and optionally flip it.
8442 It accepts the following parameters:
8447 Specify the transposition direction.
8449 Can assume the following values:
8451 @item 0, 4, cclock_flip
8452 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8460 Rotate by 90 degrees clockwise, that is:
8468 Rotate by 90 degrees counterclockwise, that is:
8475 @item 3, 7, clock_flip
8476 Rotate by 90 degrees clockwise and vertically flip, that is:
8484 For values between 4-7, the transposition is only done if the input
8485 video geometry is portrait and not landscape. These values are
8486 deprecated, the @code{passthrough} option should be used instead.
8488 Numerical values are deprecated, and should be dropped in favor of
8492 Do not apply the transposition if the input geometry matches the one
8493 specified by the specified value. It accepts the following values:
8496 Always apply transposition.
8498 Preserve portrait geometry (when @var{height} >= @var{width}).
8500 Preserve landscape geometry (when @var{width} >= @var{height}).
8503 Default value is @code{none}.
8506 For example to rotate by 90 degrees clockwise and preserve portrait
8509 transpose=dir=1:passthrough=portrait
8512 The command above can also be specified as:
8514 transpose=1:portrait
8518 Trim the input so that the output contains one continuous subpart of the input.
8520 It accepts the following parameters:
8523 Specify the time of the start of the kept section, i.e. the frame with the
8524 timestamp @var{start} will be the first frame in the output.
8527 Specify the time of the first frame that will be dropped, i.e. the frame
8528 immediately preceding the one with the timestamp @var{end} will be the last
8529 frame in the output.
8532 This is the same as @var{start}, except this option sets the start timestamp
8533 in timebase units instead of seconds.
8536 This is the same as @var{end}, except this option sets the end timestamp
8537 in timebase units instead of seconds.
8540 The maximum duration of the output in seconds.
8543 The number of the first frame that should be passed to the output.
8546 The number of the first frame that should be dropped.
8549 @option{start}, @option{end}, @option{duration} are expressed as time
8550 duration specifications, check the "Time duration" section in the
8551 ffmpeg-utils manual.
8553 Note that the first two sets of the start/end options and the @option{duration}
8554 option look at the frame timestamp, while the _frame variants simply count the
8555 frames that pass through the filter. Also note that this filter does not modify
8556 the timestamps. If you wish for the output timestamps to start at zero, insert a
8557 setpts filter after the trim filter.
8559 If multiple start or end options are set, this filter tries to be greedy and
8560 keep all the frames that match at least one of the specified constraints. To keep
8561 only the part that matches all the constraints at once, chain multiple trim
8564 The defaults are such that all the input is kept. So it is possible to set e.g.
8565 just the end values to keep everything before the specified time.
8570 Drop everything except the second minute of input:
8572 ffmpeg -i INPUT -vf trim=60:120
8576 Keep only the first second:
8578 ffmpeg -i INPUT -vf trim=duration=1
8586 Sharpen or blur the input video.
8588 It accepts the following parameters:
8591 @item luma_msize_x, lx
8592 Set the luma matrix horizontal size. It must be an odd integer between
8593 3 and 63. The default value is 5.
8595 @item luma_msize_y, ly
8596 Set the luma matrix vertical size. It must be an odd integer between 3
8597 and 63. The default value is 5.
8599 @item luma_amount, la
8600 Set the luma effect strength. It must be a floating point number, reasonable
8601 values lay between -1.5 and 1.5.
8603 Negative values will blur the input video, while positive values will
8604 sharpen it, a value of zero will disable the effect.
8606 Default value is 1.0.
8608 @item chroma_msize_x, cx
8609 Set the chroma matrix horizontal size. It must be an odd integer
8610 between 3 and 63. The default value is 5.
8612 @item chroma_msize_y, cy
8613 Set the chroma matrix vertical size. It must be an odd integer
8614 between 3 and 63. The default value is 5.
8616 @item chroma_amount, ca
8617 Set the chroma effect strength. It must be a floating point number, reasonable
8618 values lay between -1.5 and 1.5.
8620 Negative values will blur the input video, while positive values will
8621 sharpen it, a value of zero will disable the effect.
8623 Default value is 0.0.
8626 If set to 1, specify using OpenCL capabilities, only available if
8627 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8631 All parameters are optional and default to the equivalent of the
8632 string '5:5:1.0:5:5:0.0'.
8634 @subsection Examples
8638 Apply strong luma sharpen effect:
8640 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8644 Apply a strong blur of both luma and chroma parameters:
8646 unsharp=7:7:-2:7:7:-2
8650 @anchor{vidstabdetect}
8651 @section vidstabdetect
8653 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8654 @ref{vidstabtransform} for pass 2.
8656 This filter generates a file with relative translation and rotation
8657 transform information about subsequent frames, which is then used by
8658 the @ref{vidstabtransform} filter.
8660 To enable compilation of this filter you need to configure FFmpeg with
8661 @code{--enable-libvidstab}.
8663 This filter accepts the following options:
8667 Set the path to the file used to write the transforms information.
8668 Default value is @file{transforms.trf}.
8671 Set how shaky the video is and how quick the camera is. It accepts an
8672 integer in the range 1-10, a value of 1 means little shakiness, a
8673 value of 10 means strong shakiness. Default value is 5.
8676 Set the accuracy of the detection process. It must be a value in the
8677 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8678 accuracy. Default value is 15.
8681 Set stepsize of the search process. The region around minimum is
8682 scanned with 1 pixel resolution. Default value is 6.
8685 Set minimum contrast. Below this value a local measurement field is
8686 discarded. Must be a floating point value in the range 0-1. Default
8690 Set reference frame number for tripod mode.
8692 If enabled, the motion of the frames is compared to a reference frame
8693 in the filtered stream, identified by the specified number. The idea
8694 is to compensate all movements in a more-or-less static scene and keep
8695 the camera view absolutely still.
8697 If set to 0, it is disabled. The frames are counted starting from 1.
8700 Show fields and transforms in the resulting frames. It accepts an
8701 integer in the range 0-2. Default value is 0, which disables any
8705 @subsection Examples
8715 Analyze strongly shaky movie and put the results in file
8716 @file{mytransforms.trf}:
8718 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8722 Visualize the result of internal transformations in the resulting
8725 vidstabdetect=show=1
8729 Analyze a video with medium shakiness using @command{ffmpeg}:
8731 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8735 @anchor{vidstabtransform}
8736 @section vidstabtransform
8738 Video stabilization/deshaking: pass 2 of 2,
8739 see @ref{vidstabdetect} for pass 1.
8741 Read a file with transform information for each frame and
8742 apply/compensate them. Together with the @ref{vidstabdetect}
8743 filter this can be used to deshake videos. See also
8744 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8745 the unsharp filter, see below.
8747 To enable compilation of this filter you need to configure FFmpeg with
8748 @code{--enable-libvidstab}.
8754 Set path to the file used to read the transforms. Default value is
8755 @file{transforms.trf}).
8758 Set the number of frames (value*2 + 1) used for lowpass filtering the
8759 camera movements. Default value is 10.
8761 For example a number of 10 means that 21 frames are used (10 in the
8762 past and 10 in the future) to smoothen the motion in the video. A
8763 larger values leads to a smoother video, but limits the acceleration
8764 of the camera (pan/tilt movements). 0 is a special case where a
8765 static camera is simulated.
8768 Set the camera path optimization algorithm.
8770 Accepted values are:
8773 gaussian kernel low-pass filter on camera motion (default)
8775 averaging on transformations
8779 Set maximal number of pixels to translate frames. Default value is -1,
8783 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8784 value is -1, meaning no limit.
8787 Specify how to deal with borders that may be visible due to movement
8790 Available values are:
8793 keep image information from previous frame (default)
8795 fill the border black
8799 Invert transforms if set to 1. Default value is 0.
8802 Consider transforms as relative to previsou frame if set to 1,
8803 absolute if set to 0. Default value is 0.
8806 Set percentage to zoom. A positive value will result in a zoom-in
8807 effect, a negative value in a zoom-out effect. Default value is 0 (no
8811 Set optimal zooming to avoid borders.
8813 Accepted values are:
8818 optimal static zoom value is determined (only very strong movements
8819 will lead to visible borders) (default)
8821 optimal adaptive zoom value is determined (no borders will be
8822 visible), see @option{zoomspeed}
8825 Note that the value given at zoom is added to the one calculated here.
8828 Set percent to zoom maximally each frame (enabled when
8829 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8833 Specify type of interpolation.
8835 Available values are:
8840 linear only horizontal
8842 linear in both directions (default)
8844 cubic in both directions (slow)
8848 Enable virtual tripod mode if set to 1, which is equivalent to
8849 @code{relative=0:smoothing=0}. Default value is 0.
8851 Use also @code{tripod} option of @ref{vidstabdetect}.
8854 Increase log verbosity if set to 1. Also the detected global motions
8855 are written to the temporary file @file{global_motions.trf}. Default
8859 @subsection Examples
8863 Use @command{ffmpeg} for a typical stabilization with default values:
8865 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8868 Note the use of the unsharp filter which is always recommended.
8871 Zoom in a bit more and load transform data from a given file:
8873 vidstabtransform=zoom=5:input="mytransforms.trf"
8877 Smoothen the video even more:
8879 vidstabtransform=smoothing=30
8885 Flip the input video vertically.
8887 For example, to vertically flip a video with @command{ffmpeg}:
8889 ffmpeg -i in.avi -vf "vflip" out.avi
8895 Make or reverse a natural vignetting effect.
8897 The filter accepts the following options:
8901 Set lens angle expression as a number of radians.
8903 The value is clipped in the @code{[0,PI/2]} range.
8905 Default value: @code{"PI/5"}
8909 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8913 Set forward/backward mode.
8915 Available modes are:
8918 The larger the distance from the central point, the darker the image becomes.
8921 The larger the distance from the central point, the brighter the image becomes.
8922 This can be used to reverse a vignette effect, though there is no automatic
8923 detection to extract the lens @option{angle} and other settings (yet). It can
8924 also be used to create a burning effect.
8927 Default value is @samp{forward}.
8930 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8932 It accepts the following values:
8935 Evaluate expressions only once during the filter initialization.
8938 Evaluate expressions for each incoming frame. This is way slower than the
8939 @samp{init} mode since it requires all the scalers to be re-computed, but it
8940 allows advanced dynamic expressions.
8943 Default value is @samp{init}.
8946 Set dithering to reduce the circular banding effects. Default is @code{1}
8950 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8951 Setting this value to the SAR of the input will make a rectangular vignetting
8952 following the dimensions of the video.
8954 Default is @code{1/1}.
8957 @subsection Expressions
8959 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8960 following parameters.
8965 input width and height
8968 the number of input frame, starting from 0
8971 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8972 @var{TB} units, NAN if undefined
8975 frame rate of the input video, NAN if the input frame rate is unknown
8978 the PTS (Presentation TimeStamp) of the filtered video frame,
8979 expressed in seconds, NAN if undefined
8982 time base of the input video
8986 @subsection Examples
8990 Apply simple strong vignetting effect:
8996 Make a flickering vignetting:
8998 vignette='PI/4+random(1)*PI/50':eval=frame
9005 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
9006 Deinterlacing Filter").
9008 Based on the process described by Martin Weston for BBC R&D, and
9009 implemented based on the de-interlace algorithm written by Jim
9010 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
9011 uses filter coefficients calculated by BBC R&D.
9013 There are two sets of filter coefficients, so called "simple":
9014 and "complex". Which set of filter coefficients is used can
9015 be set by passing an optional parameter:
9019 Set the interlacing filter coefficients. Accepts one of the following values:
9023 Simple filter coefficient set.
9025 More-complex filter coefficient set.
9027 Default value is @samp{complex}.
9030 Specify which frames to deinterlace. Accept one of the following values:
9034 Deinterlace all frames,
9036 Only deinterlace frames marked as interlaced.
9039 Default value is @samp{all}.
9045 Deinterlace the input video ("yadif" means "yet another deinterlacing
9048 It accepts the following parameters:
9054 The interlacing mode to adopt. It accepts one of the following values:
9058 Output one frame for each frame.
9060 Output one frame for each field.
9061 @item 2, send_frame_nospatial
9062 Like @code{send_frame}, but it skips the spatial interlacing check.
9063 @item 3, send_field_nospatial
9064 Like @code{send_field}, but it skips the spatial interlacing check.
9067 The default value is @code{send_frame}.
9070 The picture field parity assumed for the input interlaced video. It accepts one
9071 of the following values:
9075 Assume the top field is first.
9077 Assume the bottom field is first.
9079 Enable automatic detection of field parity.
9082 The default value is @code{auto}.
9083 If the interlacing is unknown or the decoder does not export this information,
9084 top field first will be assumed.
9087 Specify which frames to deinterlace. Accept one of the following
9092 Deinterlace all frames.
9094 Only deinterlace frames marked as interlaced.
9097 The default value is @code{all}.
9102 Apply Zoom & Pan effect.
9104 This filter accepts the following options:
9108 Set the zoom expression. Default is 1.
9112 Set the x and y expression. Default is 0.
9115 Set the duration expression in number of frames.
9116 This sets for how many number of frames effect will last for
9120 Set the output image size, default is 'hd720'.
9123 Each expression can contain the following constants:
9146 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9147 for current input frame.
9151 'x' and 'y' of last output frame of previous input frame or 0 when there was
9152 not yet such frame (first input frame).
9155 Last calculated zoom from 'z' expression for current input frame.
9158 Last calculated zoom of last output frame of previous input frame.
9161 Number of output frames for current input frame. Calculated from 'd' expression
9162 for each input frame.
9165 number of output frames created for previous input frame
9168 Rational number: input width / input height
9174 display aspect ratio
9178 @subsection Examples
9182 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9184 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
9188 @c man end VIDEO FILTERS
9190 @chapter Video Sources
9191 @c man begin VIDEO SOURCES
9193 Below is a description of the currently available video sources.
9197 Buffer video frames, and make them available to the filter chain.
9199 This source is mainly intended for a programmatic use, in particular
9200 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9202 It accepts the following parameters:
9207 Specify the size (width and height) of the buffered video frames. For the
9208 syntax of this option, check the "Video size" section in the ffmpeg-utils
9212 The input video width.
9215 The input video height.
9218 A string representing the pixel format of the buffered video frames.
9219 It may be a number corresponding to a pixel format, or a pixel format
9223 Specify the timebase assumed by the timestamps of the buffered frames.
9226 Specify the frame rate expected for the video stream.
9228 @item pixel_aspect, sar
9229 The sample (pixel) aspect ratio of the input video.
9232 Specify the optional parameters to be used for the scale filter which
9233 is automatically inserted when an input change is detected in the
9234 input size or format.
9239 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9242 will instruct the source to accept video frames with size 320x240 and
9243 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9244 square pixels (1:1 sample aspect ratio).
9245 Since the pixel format with name "yuv410p" corresponds to the number 6
9246 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9247 this example corresponds to:
9249 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9252 Alternatively, the options can be specified as a flat string, but this
9253 syntax is deprecated:
9255 @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}]
9259 Create a pattern generated by an elementary cellular automaton.
9261 The initial state of the cellular automaton can be defined through the
9262 @option{filename}, and @option{pattern} options. If such options are
9263 not specified an initial state is created randomly.
9265 At each new frame a new row in the video is filled with the result of
9266 the cellular automaton next generation. The behavior when the whole
9267 frame is filled is defined by the @option{scroll} option.
9269 This source accepts the following options:
9273 Read the initial cellular automaton state, i.e. the starting row, from
9275 In the file, each non-whitespace character is considered an alive
9276 cell, a newline will terminate the row, and further characters in the
9277 file will be ignored.
9280 Read the initial cellular automaton state, i.e. the starting row, from
9281 the specified string.
9283 Each non-whitespace character in the string is considered an alive
9284 cell, a newline will terminate the row, and further characters in the
9285 string will be ignored.
9288 Set the video rate, that is the number of frames generated per second.
9291 @item random_fill_ratio, ratio
9292 Set the random fill ratio for the initial cellular automaton row. It
9293 is a floating point number value ranging from 0 to 1, defaults to
9296 This option is ignored when a file or a pattern is specified.
9298 @item random_seed, seed
9299 Set the seed for filling randomly the initial row, must be an integer
9300 included between 0 and UINT32_MAX. If not specified, or if explicitly
9301 set to -1, the filter will try to use a good random seed on a best
9305 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9306 Default value is 110.
9309 Set the size of the output video. For the syntax of this option, check
9310 the "Video size" section in the ffmpeg-utils manual.
9312 If @option{filename} or @option{pattern} is specified, the size is set
9313 by default to the width of the specified initial state row, and the
9314 height is set to @var{width} * PHI.
9316 If @option{size} is set, it must contain the width of the specified
9317 pattern string, and the specified pattern will be centered in the
9320 If a filename or a pattern string is not specified, the size value
9321 defaults to "320x518" (used for a randomly generated initial state).
9324 If set to 1, scroll the output upward when all the rows in the output
9325 have been already filled. If set to 0, the new generated row will be
9326 written over the top row just after the bottom row is filled.
9329 @item start_full, full
9330 If set to 1, completely fill the output with generated rows before
9331 outputting the first frame.
9332 This is the default behavior, for disabling set the value to 0.
9335 If set to 1, stitch the left and right row edges together.
9336 This is the default behavior, for disabling set the value to 0.
9339 @subsection Examples
9343 Read the initial state from @file{pattern}, and specify an output of
9346 cellauto=f=pattern:s=200x400
9350 Generate a random initial row with a width of 200 cells, with a fill
9353 cellauto=ratio=2/3:s=200x200
9357 Create a pattern generated by rule 18 starting by a single alive cell
9358 centered on an initial row with width 100:
9360 cellauto=p=@@:s=100x400:full=0:rule=18
9364 Specify a more elaborated initial pattern:
9366 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9373 Generate a Mandelbrot set fractal, and progressively zoom towards the
9374 point specified with @var{start_x} and @var{start_y}.
9376 This source accepts the following options:
9381 Set the terminal pts value. Default value is 400.
9384 Set the terminal scale value.
9385 Must be a floating point value. Default value is 0.3.
9388 Set the inner coloring mode, that is the algorithm used to draw the
9389 Mandelbrot fractal internal region.
9391 It shall assume one of the following values:
9396 Show time until convergence.
9398 Set color based on point closest to the origin of the iterations.
9403 Default value is @var{mincol}.
9406 Set the bailout value. Default value is 10.0.
9409 Set the maximum of iterations performed by the rendering
9410 algorithm. Default value is 7189.
9413 Set outer coloring mode.
9414 It shall assume one of following values:
9416 @item iteration_count
9417 Set iteration cound mode.
9418 @item normalized_iteration_count
9419 set normalized iteration count mode.
9421 Default value is @var{normalized_iteration_count}.
9424 Set frame rate, expressed as number of frames per second. Default
9428 Set frame size. For the syntax of this option, check the "Video
9429 size" section in the ffmpeg-utils manual. Default value is "640x480".
9432 Set the initial scale value. Default value is 3.0.
9435 Set the initial x position. Must be a floating point value between
9436 -100 and 100. Default value is -0.743643887037158704752191506114774.
9439 Set the initial y position. Must be a floating point value between
9440 -100 and 100. Default value is -0.131825904205311970493132056385139.
9445 Generate various test patterns, as generated by the MPlayer test filter.
9447 The size of the generated video is fixed, and is 256x256.
9448 This source is useful in particular for testing encoding features.
9450 This source accepts the following options:
9455 Specify the frame rate of the sourced video, as the number of frames
9456 generated per second. It has to be a string in the format
9457 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9458 number or a valid video frame rate abbreviation. The default value is
9462 Set the video duration of the sourced video. The accepted syntax is:
9467 See also the function @code{av_parse_time()}.
9469 If not specified, or the expressed duration is negative, the video is
9470 supposed to be generated forever.
9474 Set the number or the name of the test to perform. Supported tests are:
9490 Default value is "all", which will cycle through the list of all tests.
9498 will generate a "dc_luma" test pattern.
9502 Provide a frei0r source.
9504 To enable compilation of this filter you need to install the frei0r
9505 header and configure FFmpeg with @code{--enable-frei0r}.
9507 This source accepts the following parameters:
9512 The size of the video to generate. For the syntax of this option, check the
9513 "Video size" section in the ffmpeg-utils manual.
9516 The framerate of the generated video. It may be a string of the form
9517 @var{num}/@var{den} or a frame rate abbreviation.
9520 The name to the frei0r source to load. For more information regarding frei0r and
9521 how to set the parameters, read the @ref{frei0r} section in the video filters
9525 A '|'-separated list of parameters to pass to the frei0r source.
9529 For example, to generate a frei0r partik0l source with size 200x200
9530 and frame rate 10 which is overlayed on the overlay filter main input:
9532 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9537 Generate a life pattern.
9539 This source is based on a generalization of John Conway's life game.
9541 The sourced input represents a life grid, each pixel represents a cell
9542 which can be in one of two possible states, alive or dead. Every cell
9543 interacts with its eight neighbours, which are the cells that are
9544 horizontally, vertically, or diagonally adjacent.
9546 At each interaction the grid evolves according to the adopted rule,
9547 which specifies the number of neighbor alive cells which will make a
9548 cell stay alive or born. The @option{rule} option allows one to specify
9551 This source accepts the following options:
9555 Set the file from which to read the initial grid state. In the file,
9556 each non-whitespace character is considered an alive cell, and newline
9557 is used to delimit the end of each row.
9559 If this option is not specified, the initial grid is generated
9563 Set the video rate, that is the number of frames generated per second.
9566 @item random_fill_ratio, ratio
9567 Set the random fill ratio for the initial random grid. It is a
9568 floating point number value ranging from 0 to 1, defaults to 1/PHI.
9569 It is ignored when a file is specified.
9571 @item random_seed, seed
9572 Set the seed for filling the initial random grid, must be an integer
9573 included between 0 and UINT32_MAX. If not specified, or if explicitly
9574 set to -1, the filter will try to use a good random seed on a best
9580 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
9581 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
9582 @var{NS} specifies the number of alive neighbor cells which make a
9583 live cell stay alive, and @var{NB} the number of alive neighbor cells
9584 which make a dead cell to become alive (i.e. to "born").
9585 "s" and "b" can be used in place of "S" and "B", respectively.
9587 Alternatively a rule can be specified by an 18-bits integer. The 9
9588 high order bits are used to encode the next cell state if it is alive
9589 for each number of neighbor alive cells, the low order bits specify
9590 the rule for "borning" new cells. Higher order bits encode for an
9591 higher number of neighbor cells.
9592 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9593 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9595 Default value is "S23/B3", which is the original Conway's game of life
9596 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9597 cells, and will born a new cell if there are three alive cells around
9601 Set the size of the output video. For the syntax of this option, check the
9602 "Video size" section in the ffmpeg-utils manual.
9604 If @option{filename} is specified, the size is set by default to the
9605 same size of the input file. If @option{size} is set, it must contain
9606 the size specified in the input file, and the initial grid defined in
9607 that file is centered in the larger resulting area.
9609 If a filename is not specified, the size value defaults to "320x240"
9610 (used for a randomly generated initial grid).
9613 If set to 1, stitch the left and right grid edges together, and the
9614 top and bottom edges also. Defaults to 1.
9617 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9618 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9619 value from 0 to 255.
9622 Set the color of living (or new born) cells.
9625 Set the color of dead cells. If @option{mold} is set, this is the first color
9626 used to represent a dead cell.
9629 Set mold color, for definitely dead and moldy cells.
9631 For the syntax of these 3 color options, check the "Color" section in the
9632 ffmpeg-utils manual.
9635 @subsection Examples
9639 Read a grid from @file{pattern}, and center it on a grid of size
9642 life=f=pattern:s=300x300
9646 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9648 life=ratio=2/3:s=200x200
9652 Specify a custom rule for evolving a randomly generated grid:
9658 Full example with slow death effect (mold) using @command{ffplay}:
9660 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9665 @anchor{haldclutsrc}
9669 @anchor{smptehdbars}
9671 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9673 The @code{color} source provides an uniformly colored input.
9675 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9676 @ref{haldclut} filter.
9678 The @code{nullsrc} source returns unprocessed video frames. It is
9679 mainly useful to be employed in analysis / debugging tools, or as the
9680 source for filters which ignore the input data.
9682 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9683 detecting RGB vs BGR issues. You should see a red, green and blue
9684 stripe from top to bottom.
9686 The @code{smptebars} source generates a color bars pattern, based on
9687 the SMPTE Engineering Guideline EG 1-1990.
9689 The @code{smptehdbars} source generates a color bars pattern, based on
9690 the SMPTE RP 219-2002.
9692 The @code{testsrc} source generates a test video pattern, showing a
9693 color pattern, a scrolling gradient and a timestamp. This is mainly
9694 intended for testing purposes.
9696 The sources accept the following parameters:
9701 Specify the color of the source, only available in the @code{color}
9702 source. For the syntax of this option, check the "Color" section in the
9703 ffmpeg-utils manual.
9706 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9707 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9708 pixels to be used as identity matrix for 3D lookup tables. Each component is
9709 coded on a @code{1/(N*N)} scale.
9712 Specify the size of the sourced video. For the syntax of this option, check the
9713 "Video size" section in the ffmpeg-utils manual. The default value is
9716 This option is not available with the @code{haldclutsrc} filter.
9719 Specify the frame rate of the sourced video, as the number of frames
9720 generated per second. It has to be a string in the format
9721 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9722 number or a valid video frame rate abbreviation. The default value is
9726 Set the sample aspect ratio of the sourced video.
9729 Set the video duration of the sourced video. The accepted syntax is:
9731 [-]HH[:MM[:SS[.m...]]]
9734 Also see the the @code{av_parse_time()} function.
9736 If not specified, or the expressed duration is negative, the video is
9737 supposed to be generated forever.
9740 Set the number of decimals to show in the timestamp, only available in the
9741 @code{testsrc} source.
9743 The displayed timestamp value will correspond to the original
9744 timestamp value multiplied by the power of 10 of the specified
9745 value. Default value is 0.
9748 For example the following:
9750 testsrc=duration=5.3:size=qcif:rate=10
9753 will generate a video with a duration of 5.3 seconds, with size
9754 176x144 and a frame rate of 10 frames per second.
9756 The following graph description will generate a red source
9757 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9760 color=c=red@@0.2:s=qcif:r=10
9763 If the input content is to be ignored, @code{nullsrc} can be used. The
9764 following command generates noise in the luminance plane by employing
9765 the @code{geq} filter:
9767 nullsrc=s=256x256, geq=random(1)*255:128:128
9770 @subsection Commands
9772 The @code{color} source supports the following commands:
9776 Set the color of the created image. Accepts the same syntax of the
9777 corresponding @option{color} option.
9780 @c man end VIDEO SOURCES
9782 @chapter Video Sinks
9783 @c man begin VIDEO SINKS
9785 Below is a description of the currently available video sinks.
9789 Buffer video frames, and make them available to the end of the filter
9792 This sink is mainly intended for programmatic use, in particular
9793 through the interface defined in @file{libavfilter/buffersink.h}
9794 or the options system.
9796 It accepts a pointer to an AVBufferSinkContext structure, which
9797 defines the incoming buffers' formats, to be passed as the opaque
9798 parameter to @code{avfilter_init_filter} for initialization.
9802 Null video sink: do absolutely nothing with the input video. It is
9803 mainly useful as a template and for use in analysis / debugging
9806 @c man end VIDEO SINKS
9808 @chapter Multimedia Filters
9809 @c man begin MULTIMEDIA FILTERS
9811 Below is a description of the currently available multimedia filters.
9813 @section avectorscope
9815 Convert input audio to a video output, representing the audio vector
9818 The filter is used to measure the difference between channels of stereo
9819 audio stream. A monoaural signal, consisting of identical left and right
9820 signal, results in straight vertical line. Any stereo separation is visible
9821 as a deviation from this line, creating a Lissajous figure.
9822 If the straight (or deviation from it) but horizontal line appears this
9823 indicates that the left and right channels are out of phase.
9825 The filter accepts the following options:
9829 Set the vectorscope mode.
9831 Available values are:
9834 Lissajous rotated by 45 degrees.
9837 Same as above but not rotated.
9840 Default value is @samp{lissajous}.
9843 Set the video size for the output. For the syntax of this option, check the "Video size"
9844 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9847 Set the output frame rate. Default value is @code{25}.
9852 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9853 Allowed range is @code{[0, 255]}.
9858 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9859 Allowed range is @code{[0, 255]}.
9862 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9865 @subsection Examples
9869 Complete example using @command{ffplay}:
9871 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9872 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9878 Concatenate audio and video streams, joining them together one after the
9881 The filter works on segments of synchronized video and audio streams. All
9882 segments must have the same number of streams of each type, and that will
9883 also be the number of streams at output.
9885 The filter accepts the following options:
9890 Set the number of segments. Default is 2.
9893 Set the number of output video streams, that is also the number of video
9894 streams in each segment. Default is 1.
9897 Set the number of output audio streams, that is also the number of audio
9898 streams in each segment. Default is 0.
9901 Activate unsafe mode: do not fail if segments have a different format.
9905 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9906 @var{a} audio outputs.
9908 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9909 segment, in the same order as the outputs, then the inputs for the second
9912 Related streams do not always have exactly the same duration, for various
9913 reasons including codec frame size or sloppy authoring. For that reason,
9914 related synchronized streams (e.g. a video and its audio track) should be
9915 concatenated at once. The concat filter will use the duration of the longest
9916 stream in each segment (except the last one), and if necessary pad shorter
9917 audio streams with silence.
9919 For this filter to work correctly, all segments must start at timestamp 0.
9921 All corresponding streams must have the same parameters in all segments; the
9922 filtering system will automatically select a common pixel format for video
9923 streams, and a common sample format, sample rate and channel layout for
9924 audio streams, but other settings, such as resolution, must be converted
9925 explicitly by the user.
9927 Different frame rates are acceptable but will result in variable frame rate
9928 at output; be sure to configure the output file to handle it.
9930 @subsection Examples
9934 Concatenate an opening, an episode and an ending, all in bilingual version
9935 (video in stream 0, audio in streams 1 and 2):
9937 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9938 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9939 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9940 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9944 Concatenate two parts, handling audio and video separately, using the
9945 (a)movie sources, and adjusting the resolution:
9947 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9948 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9949 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9951 Note that a desync will happen at the stitch if the audio and video streams
9952 do not have exactly the same duration in the first file.
9958 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9959 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9960 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9961 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9963 The filter also has a video output (see the @var{video} option) with a real
9964 time graph to observe the loudness evolution. The graphic contains the logged
9965 message mentioned above, so it is not printed anymore when this option is set,
9966 unless the verbose logging is set. The main graphing area contains the
9967 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9968 the momentary loudness (400 milliseconds).
9970 More information about the Loudness Recommendation EBU R128 on
9971 @url{http://tech.ebu.ch/loudness}.
9973 The filter accepts the following options:
9978 Activate the video output. The audio stream is passed unchanged whether this
9979 option is set or no. The video stream will be the first output stream if
9980 activated. Default is @code{0}.
9983 Set the video size. This option is for video only. For the syntax of this
9984 option, check the "Video size" section in the ffmpeg-utils manual. Default
9985 and minimum resolution is @code{640x480}.
9988 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9989 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9990 other integer value between this range is allowed.
9993 Set metadata injection. If set to @code{1}, the audio input will be segmented
9994 into 100ms output frames, each of them containing various loudness information
9995 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9997 Default is @code{0}.
10000 Force the frame logging level.
10002 Available values are:
10005 information logging level
10007 verbose logging level
10010 By default, the logging level is set to @var{info}. If the @option{video} or
10011 the @option{metadata} options are set, it switches to @var{verbose}.
10016 Available modes can be cumulated (the option is a @code{flag} type). Possible
10020 Disable any peak mode (default).
10022 Enable sample-peak mode.
10024 Simple peak mode looking for the higher sample value. It logs a message
10025 for sample-peak (identified by @code{SPK}).
10027 Enable true-peak mode.
10029 If enabled, the peak lookup is done on an over-sampled version of the input
10030 stream for better peak accuracy. It logs a message for true-peak.
10031 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
10032 This mode requires a build with @code{libswresample}.
10037 @subsection Examples
10041 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
10043 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
10047 Run an analysis with @command{ffmpeg}:
10049 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
10053 @section interleave, ainterleave
10055 Temporally interleave frames from several inputs.
10057 @code{interleave} works with video inputs, @code{ainterleave} with audio.
10059 These filters read frames from several inputs and send the oldest
10060 queued frame to the output.
10062 Input streams must have a well defined, monotonically increasing frame
10065 In order to submit one frame to output, these filters need to enqueue
10066 at least one frame for each input, so they cannot work in case one
10067 input is not yet terminated and will not receive incoming frames.
10069 For example consider the case when one input is a @code{select} filter
10070 which always drop input frames. The @code{interleave} filter will keep
10071 reading from that input, but it will never be able to send new frames
10072 to output until the input will send an end-of-stream signal.
10074 Also, depending on inputs synchronization, the filters will drop
10075 frames in case one input receives more frames than the other ones, and
10076 the queue is already filled.
10078 These filters accept the following options:
10082 Set the number of different inputs, it is 2 by default.
10085 @subsection Examples
10089 Interleave frames belonging to different streams using @command{ffmpeg}:
10091 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
10095 Add flickering blur effect:
10097 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
10101 @section perms, aperms
10103 Set read/write permissions for the output frames.
10105 These filters are mainly aimed at developers to test direct path in the
10106 following filter in the filtergraph.
10108 The filters accept the following options:
10112 Select the permissions mode.
10114 It accepts the following values:
10117 Do nothing. This is the default.
10119 Set all the output frames read-only.
10121 Set all the output frames directly writable.
10123 Make the frame read-only if writable, and writable if read-only.
10125 Set each output frame read-only or writable randomly.
10129 Set the seed for the @var{random} mode, must be an integer included between
10130 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10131 @code{-1}, the filter will try to use a good random seed on a best effort
10135 Note: in case of auto-inserted filter between the permission filter and the
10136 following one, the permission might not be received as expected in that
10137 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10138 perms/aperms filter can avoid this problem.
10140 @section select, aselect
10142 Select frames to pass in output.
10144 This filter accepts the following options:
10149 Set expression, which is evaluated for each input frame.
10151 If the expression is evaluated to zero, the frame is discarded.
10153 If the evaluation result is negative or NaN, the frame is sent to the
10154 first output; otherwise it is sent to the output with index
10155 @code{ceil(val)-1}, assuming that the input index starts from 0.
10157 For example a value of @code{1.2} corresponds to the output with index
10158 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10161 Set the number of outputs. The output to which to send the selected
10162 frame is based on the result of the evaluation. Default value is 1.
10165 The expression can contain the following constants:
10169 The (sequential) number of the filtered frame, starting from 0.
10172 The (sequential) number of the selected frame, starting from 0.
10174 @item prev_selected_n
10175 The sequential number of the last selected frame. It's NAN if undefined.
10178 The timebase of the input timestamps.
10181 The PTS (Presentation TimeStamp) of the filtered video frame,
10182 expressed in @var{TB} units. It's NAN if undefined.
10185 The PTS of the filtered video frame,
10186 expressed in seconds. It's NAN if undefined.
10189 The PTS of the previously filtered video frame. It's NAN if undefined.
10191 @item prev_selected_pts
10192 The PTS of the last previously filtered video frame. It's NAN if undefined.
10194 @item prev_selected_t
10195 The PTS of the last previously selected video frame. It's NAN if undefined.
10198 The PTS of the first video frame in the video. It's NAN if undefined.
10201 The time of the first video frame in the video. It's NAN if undefined.
10203 @item pict_type @emph{(video only)}
10204 The type of the filtered frame. It can assume one of the following
10216 @item interlace_type @emph{(video only)}
10217 The frame interlace type. It can assume one of the following values:
10220 The frame is progressive (not interlaced).
10222 The frame is top-field-first.
10224 The frame is bottom-field-first.
10227 @item consumed_sample_n @emph{(audio only)}
10228 the number of selected samples before the current frame
10230 @item samples_n @emph{(audio only)}
10231 the number of samples in the current frame
10233 @item sample_rate @emph{(audio only)}
10234 the input sample rate
10237 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10240 the position in the file of the filtered frame, -1 if the information
10241 is not available (e.g. for synthetic video)
10243 @item scene @emph{(video only)}
10244 value between 0 and 1 to indicate a new scene; a low value reflects a low
10245 probability for the current frame to introduce a new scene, while a higher
10246 value means the current frame is more likely to be one (see the example below)
10250 The default value of the select expression is "1".
10252 @subsection Examples
10256 Select all frames in input:
10261 The example above is the same as:
10273 Select only I-frames:
10275 select='eq(pict_type\,I)'
10279 Select one frame every 100:
10281 select='not(mod(n\,100))'
10285 Select only frames contained in the 10-20 time interval:
10287 select=between(t\,10\,20)
10291 Select only I frames contained in the 10-20 time interval:
10293 select=between(t\,10\,20)*eq(pict_type\,I)
10297 Select frames with a minimum distance of 10 seconds:
10299 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10303 Use aselect to select only audio frames with samples number > 100:
10305 aselect='gt(samples_n\,100)'
10309 Create a mosaic of the first scenes:
10311 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10314 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10318 Send even and odd frames to separate outputs, and compose them:
10320 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10324 @section sendcmd, asendcmd
10326 Send commands to filters in the filtergraph.
10328 These filters read commands to be sent to other filters in the
10331 @code{sendcmd} must be inserted between two video filters,
10332 @code{asendcmd} must be inserted between two audio filters, but apart
10333 from that they act the same way.
10335 The specification of commands can be provided in the filter arguments
10336 with the @var{commands} option, or in a file specified by the
10337 @var{filename} option.
10339 These filters accept the following options:
10342 Set the commands to be read and sent to the other filters.
10344 Set the filename of the commands to be read and sent to the other
10348 @subsection Commands syntax
10350 A commands description consists of a sequence of interval
10351 specifications, comprising a list of commands to be executed when a
10352 particular event related to that interval occurs. The occurring event
10353 is typically the current frame time entering or leaving a given time
10356 An interval is specified by the following syntax:
10358 @var{START}[-@var{END}] @var{COMMANDS};
10361 The time interval is specified by the @var{START} and @var{END} times.
10362 @var{END} is optional and defaults to the maximum time.
10364 The current frame time is considered within the specified interval if
10365 it is included in the interval [@var{START}, @var{END}), that is when
10366 the time is greater or equal to @var{START} and is lesser than
10369 @var{COMMANDS} consists of a sequence of one or more command
10370 specifications, separated by ",", relating to that interval. The
10371 syntax of a command specification is given by:
10373 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10376 @var{FLAGS} is optional and specifies the type of events relating to
10377 the time interval which enable sending the specified command, and must
10378 be a non-null sequence of identifier flags separated by "+" or "|" and
10379 enclosed between "[" and "]".
10381 The following flags are recognized:
10384 The command is sent when the current frame timestamp enters the
10385 specified interval. In other words, the command is sent when the
10386 previous frame timestamp was not in the given interval, and the
10390 The command is sent when the current frame timestamp leaves the
10391 specified interval. In other words, the command is sent when the
10392 previous frame timestamp was in the given interval, and the
10396 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10399 @var{TARGET} specifies the target of the command, usually the name of
10400 the filter class or a specific filter instance name.
10402 @var{COMMAND} specifies the name of the command for the target filter.
10404 @var{ARG} is optional and specifies the optional list of argument for
10405 the given @var{COMMAND}.
10407 Between one interval specification and another, whitespaces, or
10408 sequences of characters starting with @code{#} until the end of line,
10409 are ignored and can be used to annotate comments.
10411 A simplified BNF description of the commands specification syntax
10414 @var{COMMAND_FLAG} ::= "enter" | "leave"
10415 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10416 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10417 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10418 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10419 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10422 @subsection Examples
10426 Specify audio tempo change at second 4:
10428 asendcmd=c='4.0 atempo tempo 1.5',atempo
10432 Specify a list of drawtext and hue commands in a file.
10434 # show text in the interval 5-10
10435 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10436 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10438 # desaturate the image in the interval 15-20
10439 15.0-20.0 [enter] hue s 0,
10440 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10442 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10444 # apply an exponential saturation fade-out effect, starting from time 25
10445 25 [enter] hue s exp(25-t)
10448 A filtergraph allowing to read and process the above command list
10449 stored in a file @file{test.cmd}, can be specified with:
10451 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10456 @section setpts, asetpts
10458 Change the PTS (presentation timestamp) of the input frames.
10460 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10462 This filter accepts the following options:
10467 The expression which is evaluated for each frame to construct its timestamp.
10471 The expression is evaluated through the eval API and can contain the following
10476 frame rate, only defined for constant frame-rate video
10479 The presentation timestamp in input
10482 The count of the input frame for video or the number of consumed samples,
10483 not including the current frame for audio, starting from 0.
10485 @item NB_CONSUMED_SAMPLES
10486 The number of consumed samples, not including the current frame (only
10489 @item NB_SAMPLES, S
10490 The number of samples in the current frame (only audio)
10492 @item SAMPLE_RATE, SR
10493 The audio sample rate.
10496 The PTS of the first frame.
10499 the time in seconds of the first frame
10502 State whether the current frame is interlaced.
10505 the time in seconds of the current frame
10508 original position in the file of the frame, or undefined if undefined
10509 for the current frame
10512 The previous input PTS.
10515 previous input time in seconds
10518 The previous output PTS.
10521 previous output time in seconds
10524 The wallclock (RTC) time in microseconds.. This is deprecated, use time(0)
10528 The wallclock (RTC) time at the start of the movie in microseconds.
10531 The timebase of the input timestamps.
10535 @subsection Examples
10539 Start counting PTS from zero
10541 setpts=PTS-STARTPTS
10545 Apply fast motion effect:
10551 Apply slow motion effect:
10557 Set fixed rate of 25 frames per second:
10563 Set fixed rate 25 fps with some jitter:
10565 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
10569 Apply an offset of 10 seconds to the input PTS:
10575 Generate timestamps from a "live source" and rebase onto the current timebase:
10577 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
10581 Generate timestamps by counting samples:
10588 @section settb, asettb
10590 Set the timebase to use for the output frames timestamps.
10591 It is mainly useful for testing timebase configuration.
10593 It accepts the following parameters:
10598 The expression which is evaluated into the output timebase.
10602 The value for @option{tb} is an arithmetic expression representing a
10603 rational. The expression can contain the constants "AVTB" (the default
10604 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10605 audio only). Default value is "intb".
10607 @subsection Examples
10611 Set the timebase to 1/25:
10617 Set the timebase to 1/10:
10623 Set the timebase to 1001/1000:
10629 Set the timebase to 2*intb:
10635 Set the default timebase value:
10642 Convert input audio to a video output representing
10643 frequency spectrum logarithmically (using constant Q transform with
10644 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
10646 The filter accepts the following options:
10650 Specify transform volume (multiplier) expression. The expression can contain
10653 @item frequency, freq, f
10654 the frequency where transform is evaluated
10655 @item timeclamp, tc
10656 value of timeclamp option
10660 @item a_weighting(f)
10661 A-weighting of equal loudness
10662 @item b_weighting(f)
10663 B-weighting of equal loudness
10664 @item c_weighting(f)
10665 C-weighting of equal loudness
10667 Default value is @code{16}.
10670 Specify transform length expression. The expression can contain variables:
10672 @item frequency, freq, f
10673 the frequency where transform is evaluated
10674 @item timeclamp, tc
10675 value of timeclamp option
10677 Default value is @code{384/f*tc/(384/f+tc)}.
10680 Specify the transform timeclamp. At low frequency, there is trade-off between
10681 accuracy in time domain and frequency domain. If timeclamp is lower,
10682 event in time domain is represented more accurately (such as fast bass drum),
10683 otherwise event in frequency domain is represented more accurately
10684 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
10687 Specify the transform coeffclamp. If coeffclamp is lower, transform is
10688 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
10689 Default value is @code{1.0}.
10692 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
10693 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
10694 Default value is @code{3.0}.
10697 Specify font file for use with freetype. If not specified, use embedded font.
10700 Specify font color expression. This is arithmetic expression that should return
10701 integer value 0xRRGGBB. The expression can contain variables:
10703 @item frequency, freq, f
10704 the frequency where transform is evaluated
10705 @item timeclamp, tc
10706 value of timeclamp option
10711 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
10712 @item r(x), g(x), b(x)
10713 red, green, and blue value of intensity x
10715 Default value is @code{st(0, (midi(f)-59.5)/12);
10716 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
10717 r(1-ld(1)) + b(ld(1))}
10720 If set to 1 (the default), the video size is 1920x1080 (full HD),
10721 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
10724 Specify video fps. Default value is @code{25}.
10727 Specify number of transform per frame, so there are fps*count transforms
10728 per second. Note that audio data rate must be divisible by fps*count.
10729 Default value is @code{6}.
10733 @subsection Examples
10737 Playing audio while showing the spectrum:
10739 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
10743 Same as above, but with frame rate 30 fps:
10745 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
10749 Playing at 960x540 and lower CPU usage:
10751 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
10755 A1 and its harmonics: A1, A2, (near)E3, A3:
10757 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),
10758 asplit[a][out1]; [a] showcqt [out0]'
10762 Same as above, but with more accuracy in frequency domain (and slower):
10764 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),
10765 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
10769 B-weighting of equal loudness
10771 volume=16*b_weighting(f)
10777 tlength=100/f*tc/(100/f+tc)
10781 Custom fontcolor, C-note is colored green, others are colored blue
10783 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
10788 @section showspectrum
10790 Convert input audio to a video output, representing the audio frequency
10793 The filter accepts the following options:
10797 Specify the video size for the output. For the syntax of this option, check
10798 the "Video size" section in the ffmpeg-utils manual. Default value is
10802 Specify how the spectrum should slide along the window.
10804 It accepts the following values:
10807 the samples start again on the left when they reach the right
10809 the samples scroll from right to left
10811 frames are only produced when the samples reach the right
10814 Default value is @code{replace}.
10817 Specify display mode.
10819 It accepts the following values:
10822 all channels are displayed in the same row
10824 all channels are displayed in separate rows
10827 Default value is @samp{combined}.
10830 Specify display color mode.
10832 It accepts the following values:
10835 each channel is displayed in a separate color
10837 each channel is is displayed using the same color scheme
10840 Default value is @samp{channel}.
10843 Specify scale used for calculating intensity color values.
10845 It accepts the following values:
10850 square root, default
10857 Default value is @samp{sqrt}.
10860 Set saturation modifier for displayed colors. Negative values provide
10861 alternative color scheme. @code{0} is no saturation at all.
10862 Saturation must be in [-10.0, 10.0] range.
10863 Default value is @code{1}.
10866 Set window function.
10868 It accepts the following values:
10871 No samples pre-processing (do not expect this to be faster)
10880 Default value is @code{hann}.
10883 The usage is very similar to the showwaves filter; see the examples in that
10886 @subsection Examples
10890 Large window with logarithmic color scaling:
10892 showspectrum=s=1280x480:scale=log
10896 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10898 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10899 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10905 Convert input audio to a video output, representing the samples waves.
10907 The filter accepts the following options:
10911 Specify the video size for the output. For the syntax of this option, check
10912 the "Video size" section in the ffmpeg-utils manual. Default value
10918 Available values are:
10921 Draw a point for each sample.
10924 Draw a vertical line for each sample.
10927 Draw a point for each sample and a line between them.
10930 Draw a centered vertical line for each sample.
10933 Default value is @code{point}.
10936 Set the number of samples which are printed on the same column. A
10937 larger value will decrease the frame rate. Must be a positive
10938 integer. This option can be set only if the value for @var{rate}
10939 is not explicitly specified.
10942 Set the (approximate) output frame rate. This is done by setting the
10943 option @var{n}. Default value is "25".
10945 @item split_channels
10946 Set if channels should be drawn separately or overlap. Default value is 0.
10950 @subsection Examples
10954 Output the input file audio and the corresponding video representation
10957 amovie=a.mp3,asplit[out0],showwaves[out1]
10961 Create a synthetic signal and show it with showwaves, forcing a
10962 frame rate of 30 frames per second:
10964 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10968 @section split, asplit
10970 Split input into several identical outputs.
10972 @code{asplit} works with audio input, @code{split} with video.
10974 The filter accepts a single parameter which specifies the number of outputs. If
10975 unspecified, it defaults to 2.
10977 @subsection Examples
10981 Create two separate outputs from the same input:
10983 [in] split [out0][out1]
10987 To create 3 or more outputs, you need to specify the number of
10990 [in] asplit=3 [out0][out1][out2]
10994 Create two separate outputs from the same input, one cropped and
10997 [in] split [splitout1][splitout2];
10998 [splitout1] crop=100:100:0:0 [cropout];
10999 [splitout2] pad=200:200:100:100 [padout];
11003 Create 5 copies of the input audio with @command{ffmpeg}:
11005 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
11011 Receive commands sent through a libzmq client, and forward them to
11012 filters in the filtergraph.
11014 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
11015 must be inserted between two video filters, @code{azmq} between two
11018 To enable these filters you need to install the libzmq library and
11019 headers and configure FFmpeg with @code{--enable-libzmq}.
11021 For more information about libzmq see:
11022 @url{http://www.zeromq.org/}
11024 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
11025 receives messages sent through a network interface defined by the
11026 @option{bind_address} option.
11028 The received message must be in the form:
11030 @var{TARGET} @var{COMMAND} [@var{ARG}]
11033 @var{TARGET} specifies the target of the command, usually the name of
11034 the filter class or a specific filter instance name.
11036 @var{COMMAND} specifies the name of the command for the target filter.
11038 @var{ARG} is optional and specifies the optional argument list for the
11039 given @var{COMMAND}.
11041 Upon reception, the message is processed and the corresponding command
11042 is injected into the filtergraph. Depending on the result, the filter
11043 will send a reply to the client, adopting the format:
11045 @var{ERROR_CODE} @var{ERROR_REASON}
11049 @var{MESSAGE} is optional.
11051 @subsection Examples
11053 Look at @file{tools/zmqsend} for an example of a zmq client which can
11054 be used to send commands processed by these filters.
11056 Consider the following filtergraph generated by @command{ffplay}
11058 ffplay -dumpgraph 1 -f lavfi "
11059 color=s=100x100:c=red [l];
11060 color=s=100x100:c=blue [r];
11061 nullsrc=s=200x100, zmq [bg];
11062 [bg][l] overlay [bg+l];
11063 [bg+l][r] overlay=x=100 "
11066 To change the color of the left side of the video, the following
11067 command can be used:
11069 echo Parsed_color_0 c yellow | tools/zmqsend
11072 To change the right side:
11074 echo Parsed_color_1 c pink | tools/zmqsend
11077 @c man end MULTIMEDIA FILTERS
11079 @chapter Multimedia Sources
11080 @c man begin MULTIMEDIA SOURCES
11082 Below is a description of the currently available multimedia sources.
11086 This is the same as @ref{movie} source, except it selects an audio
11092 Read audio and/or video stream(s) from a movie container.
11094 It accepts the following parameters:
11098 The name of the resource to read (not necessarily a file; it can also be a
11099 device or a stream accessed through some protocol).
11101 @item format_name, f
11102 Specifies the format assumed for the movie to read, and can be either
11103 the name of a container or an input device. If not specified, the
11104 format is guessed from @var{movie_name} or by probing.
11106 @item seek_point, sp
11107 Specifies the seek point in seconds. The frames will be output
11108 starting from this seek point. The parameter is evaluated with
11109 @code{av_strtod}, so the numerical value may be suffixed by an IS
11110 postfix. The default value is "0".
11113 Specifies the streams to read. Several streams can be specified,
11114 separated by "+". The source will then have as many outputs, in the
11115 same order. The syntax is explained in the ``Stream specifiers''
11116 section in the ffmpeg manual. Two special names, "dv" and "da" specify
11117 respectively the default (best suited) video and audio stream. Default
11118 is "dv", or "da" if the filter is called as "amovie".
11120 @item stream_index, si
11121 Specifies the index of the video stream to read. If the value is -1,
11122 the most suitable video stream will be automatically selected. The default
11123 value is "-1". Deprecated. If the filter is called "amovie", it will select
11124 audio instead of video.
11127 Specifies how many times to read the stream in sequence.
11128 If the value is less than 1, the stream will be read again and again.
11129 Default value is "1".
11131 Note that when the movie is looped the source timestamps are not
11132 changed, so it will generate non monotonically increasing timestamps.
11135 It allows overlaying a second video on top of the main input of
11136 a filtergraph, as shown in this graph:
11138 input -----------> deltapts0 --> overlay --> output
11141 movie --> scale--> deltapts1 -------+
11143 @subsection Examples
11147 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
11148 on top of the input labelled "in":
11150 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
11151 [in] setpts=PTS-STARTPTS [main];
11152 [main][over] overlay=16:16 [out]
11156 Read from a video4linux2 device, and overlay it on top of the input
11159 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
11160 [in] setpts=PTS-STARTPTS [main];
11161 [main][over] overlay=16:16 [out]
11165 Read the first video stream and the audio stream with id 0x81 from
11166 dvd.vob; the video is connected to the pad named "video" and the audio is
11167 connected to the pad named "audio":
11169 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
11173 @c man end MULTIMEDIA SOURCES