Provided by: ffmpeg_3.3.4-2_amd64 bug

NAME

       ffmpeg-filters - FFmpeg filters

DESCRIPTION

       This document describes filters, sources, and sinks provided by the libavfilter library.

FILTERING INTRODUCTION

       Filtering in FFmpeg is enabled through the libavfilter library.

       In libavfilter, a filter can have multiple inputs and multiple outputs.  To illustrate the
       sorts of things that are possible, we consider the following filtergraph.

                               [main]
               input --> split ---------------------> overlay --> output
                           |                             ^
                           |[tmp]                  [flip]|
                           +-----> crop --> vflip -------+

       This filtergraph splits the input stream in two streams, then sends one stream through the
       crop filter and the vflip filter, before merging it back with the other stream by
       overlaying it on top. You can use the following command to achieve this:

               ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT

       The result will be that the top half of the video is mirrored onto the bottom half of the
       output video.

       Filters in the same linear chain are separated by commas, and distinct linear chains of
       filters are separated by semicolons. In our example, crop,vflip are in one linear chain,
       split and overlay are separately in another. The points where the linear chains join are
       labelled by names enclosed in square brackets. In the example, the split filter generates
       two outputs that are associated to the labels [main] and [tmp].

       The stream sent to the second output of split, labelled as [tmp], is processed through the
       crop filter, which crops away the lower half part of the video, and then vertically
       flipped. The overlay filter takes in input the first unchanged output of the split filter
       (which was labelled as [main]), and overlay on its lower half the output generated by the
       crop,vflip filterchain.

       Some filters take in input a list of parameters: they are specified after the filter name
       and an equal sign, and are separated from each other by a colon.

       There exist so-called source filters that do not have an audio/video input, and sink
       filters that will not have audio/video output.

GRAPH

       The graph2dot program included in the FFmpeg tools directory can be used to parse a
       filtergraph description and issue a corresponding textual representation in the dot
       language.

       Invoke the command:

               graph2dot -h

       to see how to use graph2dot.

       You can then pass the dot description to the dot program (from the graphviz suite of
       programs) and obtain a graphical representation of the filtergraph.

       For example the sequence of commands:

               echo <GRAPH_DESCRIPTION> | \
               tools/graph2dot -o graph.tmp && \
               dot -Tpng graph.tmp -o graph.png && \
               display graph.png

       can be used to create and display an image representing the graph described by the
       GRAPH_DESCRIPTION string. Note that this string must be a complete self-contained graph,
       with its inputs and outputs explicitly defined.  For example if your command line is of
       the form:

               ffmpeg -i infile -vf scale=640:360 outfile

       your GRAPH_DESCRIPTION string will need to be of the form:

               nullsrc,scale=640:360,nullsink

       you may also need to set the nullsrc parameters and add a format filter in order to
       simulate a specific input file.

FILTERGRAPH DESCRIPTION

       A filtergraph is a directed graph of connected filters. It can contain cycles, and there
       can be multiple links between a pair of filters. Each link has one input pad on one side
       connecting it to one filter from which it takes its input, and one output pad on the other
       side connecting it to one filter accepting its output.

       Each filter in a filtergraph is an instance of a filter class registered in the
       application, which defines the features and the number of input and output pads of the
       filter.

       A filter with no input pads is called a "source", and a filter with no output pads is
       called a "sink".

   Filtergraph syntax
       A filtergraph has a textual representation, which is recognized by the -filter/-vf/-af and
       -filter_complex options in ffmpeg and -vf/-af in ffplay, and by the
       "avfilter_graph_parse_ptr()" function defined in libavfilter/avfilter.h.

       A filterchain consists of a sequence of connected filters, each one connected to the
       previous one in the sequence. A filterchain is represented by a list of ","-separated
       filter descriptions.

       A filtergraph consists of a sequence of filterchains. A sequence of filterchains is
       represented by a list of ";"-separated filterchain descriptions.

       A filter is represented by a string of the form:
       [in_link_1]...[in_link_N]filter_name=arguments[out_link_1]...[out_link_M]

       filter_name is the name of the filter class of which the described filter is an instance
       of, and has to be the name of one of the filter classes registered in the program.  The
       name of the filter class is optionally followed by a string "=arguments".

       arguments is a string which contains the parameters used to initialize the filter
       instance. It may have one of two forms:

       ·   A ':'-separated list of key=value pairs.

       ·   A ':'-separated list of value. In this case, the keys are assumed to be the option
           names in the order they are declared. E.g. the "fade" filter declares three options in
           this order -- type, start_frame and nb_frames. Then the parameter list in:0:30 means
           that the value in is assigned to the option type, 0 to start_frame and 30 to
           nb_frames.

       ·   A ':'-separated list of mixed direct value and long key=value pairs. The direct value
           must precede the key=value pairs, and follow the same constraints order of the
           previous point. The following key=value pairs can be set in any preferred order.

       If the option value itself is a list of items (e.g. the "format" filter takes a list of
       pixel formats), the items in the list are usually separated by |.

       The list of arguments can be quoted using the character ' as initial and ending mark, and
       the character \ for escaping the characters within the quoted text; otherwise the argument
       string is considered terminated when the next special character (belonging to the set
       []=;,) is encountered.

       The name and arguments of the filter are optionally preceded and followed by a list of
       link labels.  A link label allows one to name a link and associate it to a filter output
       or input pad. The preceding labels in_link_1 ... in_link_N, are associated to the filter
       input pads, the following labels out_link_1 ... out_link_M, are associated to the output
       pads.

       When two link labels with the same name are found in the filtergraph, a link between the
       corresponding input and output pad is created.

       If an output pad is not labelled, it is linked by default to the first unlabelled input
       pad of the next filter in the filterchain.  For example in the filterchain

               nullsrc, split[L1], [L2]overlay, nullsink

       the split filter instance has two output pads, and the overlay filter instance two input
       pads. The first output pad of split is labelled "L1", the first input pad of overlay is
       labelled "L2", and the second output pad of split is linked to the second input pad of
       overlay, which are both unlabelled.

       In a filter description, if the input label of the first filter is not specified, "in" is
       assumed; if the output label of the last filter is not specified, "out" is assumed.

       In a complete filterchain all the unlabelled filter input and output pads must be
       connected. A filtergraph is considered valid if all the filter input and output pads of
       all the filterchains are connected.

       Libavfilter will automatically insert scale filters where format conversion is required.
       It is possible to specify swscale flags for those automatically inserted scalers by
       prepending "sws_flags=flags;" to the filtergraph description.

       Here is a BNF description of the filtergraph syntax:

               <NAME>             ::= sequence of alphanumeric characters and '_'
               <LINKLABEL>        ::= "[" <NAME> "]"
               <LINKLABELS>       ::= <LINKLABEL> [<LINKLABELS>]
               <FILTER_ARGUMENTS> ::= sequence of chars (possibly quoted)
               <FILTER>           ::= [<LINKLABELS>] <NAME> ["=" <FILTER_ARGUMENTS>] [<LINKLABELS>]
               <FILTERCHAIN>      ::= <FILTER> [,<FILTERCHAIN>]
               <FILTERGRAPH>      ::= [sws_flags=<flags>;] <FILTERCHAIN> [;<FILTERGRAPH>]

   Notes on filtergraph escaping
       Filtergraph description composition entails several levels of escaping. See the "Quoting
       and escaping" section in the ffmpeg-utils(1) manual for more information about the
       employed escaping procedure.

       A first level escaping affects the content of each filter option value, which may contain
       the special character ":" used to separate values, or one of the escaping characters "\'".

       A second level escaping affects the whole filter description, which may contain the
       escaping characters "\'" or the special characters "[],;" used by the filtergraph
       description.

       Finally, when you specify a filtergraph on a shell commandline, you need to perform a
       third level escaping for the shell special characters contained within it.

       For example, consider the following string to be embedded in the drawtext filter
       description text value:

               this is a 'string': may contain one, or more, special characters

       This string contains the "'" special escaping character, and the ":" special character, so
       it needs to be escaped in this way:

               text=this is a \'string\'\: may contain one, or more, special characters

       A second level of escaping is required when embedding the filter description in a
       filtergraph description, in order to escape all the filtergraph special characters. Thus
       the example above becomes:

               drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters

       (note that in addition to the "\'" escaping special characters, also "," needs to be
       escaped).

       Finally an additional level of escaping is needed when writing the filtergraph description
       in a shell command, which depends on the escaping rules of the adopted shell. For example,
       assuming that "\" is special and needs to be escaped with another "\", the previous string
       will finally result in:

               -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"

TIMELINE EDITING

       Some filters support a generic enable option. For the filters supporting timeline editing,
       this option can be set to an expression which is evaluated before sending a frame to the
       filter. If the evaluation is non-zero, the filter will be enabled, otherwise the frame
       will be sent unchanged to the next filter in the filtergraph.

       The expression accepts the following values:

       t   timestamp expressed in seconds, NAN if the input timestamp is unknown

       n   sequential number of the input frame, starting from 0

       pos the position in the file of the input frame, NAN if unknown

       w
       h   width and height of the input frame if video

       Additionally, these filters support an enable command that can be used to re-define the
       expression.

       Like any other filtering option, the enable option follows the same rules.

       For example, to enable a blur filter (smartblur) from 10 seconds to 3 minutes, and a
       curves filter starting at 3 seconds:

               smartblur = enable='between(t,10,3*60)',
               curves    = enable='gte(t,3)' : preset=cross_process

       See "ffmpeg -filters" to view which filters have timeline support.

AUDIO FILTERS

       When you configure your FFmpeg build, you can disable any of the existing filters using
       "--disable-filters".  The configure output will show the audio filters included in your
       build.

       Below is a description of the currently available audio filters.

   acompressor
       A compressor is mainly used to reduce the dynamic range of a signal.  Especially modern
       music is mostly compressed at a high ratio to improve the overall loudness. It's done to
       get the highest attention of a listener, "fatten" the sound and bring more "power" to the
       track.  If a signal is compressed too much it may sound dull or "dead" afterwards or it
       may start to "pump" (which could be a powerful effect but can also destroy a track
       completely).  The right compression is the key to reach a professional sound and is the
       high art of mixing and mastering. Because of its complex settings it may take a long time
       to get the right feeling for this kind of effect.

       Compression is done by detecting the volume above a chosen level "threshold" and dividing
       it by the factor set with "ratio".  So if you set the threshold to -12dB and your signal
       reaches -6dB a ratio of 2:1 will result in a signal at -9dB. Because an exact manipulation
       of the signal would cause distortion of the waveform the reduction can be levelled over
       the time. This is done by setting "Attack" and "Release".  "attack" determines how long
       the signal has to rise above the threshold before any reduction will occur and "release"
       sets the time the signal has to fall below the threshold to reduce the reduction again.
       Shorter signals than the chosen attack time will be left untouched.  The overall reduction
       of the signal can be made up afterwards with the "makeup" setting. So compressing the
       peaks of a signal about 6dB and raising the makeup to this level results in a signal twice
       as loud than the source. To gain a softer entry in the compression the "knee" flattens the
       hard edge at the threshold in the range of the chosen decibels.

       The filter accepts the following options:

       level_in
           Set input gain. Default is 1. Range is between 0.015625 and 64.

       threshold
           If a signal of second stream rises above this level it will affect the gain reduction
           of the first stream.  By default it is 0.125. Range is between 0.00097563 and 1.

       ratio
           Set a ratio by which the signal is reduced. 1:2 means that if the level rose 4dB above
           the threshold, it will be only 2dB above after the reduction.  Default is 2. Range is
           between 1 and 20.

       attack
           Amount of milliseconds the signal has to rise above the threshold before gain
           reduction starts. Default is 20. Range is between 0.01 and 2000.

       release
           Amount of milliseconds the signal has to fall below the threshold before reduction is
           decreased again. Default is 250. Range is between 0.01 and 9000.

       makeup
           Set the amount by how much signal will be amplified after processing.  Default is 2.
           Range is from 1 and 64.

       knee
           Curve the sharp knee around the threshold to enter gain reduction more softly.
           Default is 2.82843. Range is between 1 and 8.

       link
           Choose if the "average" level between all channels of input stream or the
           louder("maximum") channel of input stream affects the reduction. Default is "average".

       detection
           Should the exact signal be taken in case of "peak" or an RMS one in case of "rms".
           Default is "rms" which is mostly smoother.

       mix How much to use compressed signal in output. Default is 1.  Range is between 0 and 1.

   acrossfade
       Apply cross fade from one input audio stream to another input audio stream.  The cross
       fade is applied for specified duration near the end of first stream.

       The filter accepts the following options:

       nb_samples, ns
           Specify the number of samples for which the cross fade effect has to last.  At the end
           of the cross fade effect the first input audio will be completely silent. Default is
           44100.

       duration, d
           Specify the duration of the cross fade effect. See the Time duration section in the
           ffmpeg-utils(1) manual for the accepted syntax.  By default the duration is determined
           by nb_samples.  If set this option is used instead of nb_samples.

       overlap, o
           Should first stream end overlap with second stream start. Default is enabled.

       curve1
           Set curve for cross fade transition for first stream.

       curve2
           Set curve for cross fade transition for second stream.

           For description of available curve types see afade filter description.

       Examples

       ·   Cross fade from one input to another:

                   ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac

       ·   Cross fade from one input to another but without overlapping:

                   ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac

   acrusher
       Reduce audio bit resolution.

       This filter is bit crusher with enhanced functionality. A bit crusher is used to audibly
       reduce number of bits an audio signal is sampled with. This doesn't change the bit depth
       at all, it just produces the effect. Material reduced in bit depth sounds more harsh and
       "digital".  This filter is able to even round to continuous values instead of discrete bit
       depths.  Additionally it has a D/C offset which results in different crushing of the lower
       and the upper half of the signal.  An Anti-Aliasing setting is able to produce "softer"
       crushing sounds.

       Another feature of this filter is the logarithmic mode.  This setting switches from linear
       distances between bits to logarithmic ones.  The result is a much more "natural" sounding
       crusher which doesn't gate low signals for example. The human ear has a logarithmic
       perception, too so this kind of crushing is much more pleasant.  Logarithmic crushing is
       also able to get anti-aliased.

       The filter accepts the following options:

       level_in
           Set level in.

       level_out
           Set level out.

       bits
           Set bit reduction.

       mix Set mixing amount.

       mode
           Can be linear: "lin" or logarithmic: "log".

       dc  Set DC.

       aa  Set anti-aliasing.

       samples
           Set sample reduction.

       lfo Enable LFO. By default disabled.

       lforange
           Set LFO range.

       lforate
           Set LFO rate.

   adelay
       Delay one or more audio channels.

       Samples in delayed channel are filled with silence.

       The filter accepts the following option:

       delays
           Set list of delays in milliseconds for each channel separated by '|'.  At least one
           delay greater than 0 should be provided.  Unused delays will be silently ignored. If
           number of given delays is smaller than number of channels all remaining channels will
           not be delayed.  If you want to delay exact number of samples, append 'S' to number.

       Examples

       ·   Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave the
           second channel (and any other channels that may be present) unchanged.

                   adelay=1500|0|500

       ·   Delay second channel by 500 samples, the third channel by 700 samples and leave the
           first channel (and any other channels that may be present) unchanged.

                   adelay=0|500S|700S

   aecho
       Apply echoing to the input audio.

       Echoes are reflected sound and can occur naturally amongst mountains (and sometimes large
       buildings) when talking or shouting; digital echo effects emulate this behaviour and are
       often used to help fill out the sound of a single instrument or vocal. The time difference
       between the original signal and the reflection is the "delay", and the loudness of the
       reflected signal is the "decay".  Multiple echoes can have different delays and decays.

       A description of the accepted parameters follows.

       in_gain
           Set input gain of reflected signal. Default is 0.6.

       out_gain
           Set output gain of reflected signal. Default is 0.3.

       delays
           Set list of time intervals in milliseconds between original signal and reflections
           separated by '|'. Allowed range for each "delay" is "(0 - 90000.0]".  Default is 1000.

       decays
           Set list of loudnesses of reflected signals separated by '|'.  Allowed range for each
           "decay" is "(0 - 1.0]".  Default is 0.5.

       Examples

       ·   Make it sound as if there are twice as many instruments as are actually playing:

                   aecho=0.8:0.88:60:0.4

       ·   If delay is very short, then it sound like a (metallic) robot playing music:

                   aecho=0.8:0.88:6:0.4

       ·   A longer delay will sound like an open air concert in the mountains:

                   aecho=0.8:0.9:1000:0.3

       ·   Same as above but with one more mountain:

                   aecho=0.8:0.9:1000|1800:0.3|0.25

   aemphasis
       Audio emphasis filter creates or restores material directly taken from LPs or emphased CDs
       with different filter curves. E.g. to store music on vinyl the signal has to be altered by
       a filter first to even out the disadvantages of this recording medium.  Once the material
       is played back the inverse filter has to be applied to restore the distortion of the
       frequency response.

       The filter accepts the following options:

       level_in
           Set input gain.

       level_out
           Set output gain.

       mode
           Set filter mode. For restoring material use "reproduction" mode, otherwise use
           "production" mode. Default is "reproduction" mode.

       type
           Set filter type. Selects medium. Can be one of the following:

           col select Columbia.

           emi select EMI.

           bsi select BSI (78RPM).

           riaa
               select RIAA.

           cd  select Compact Disc (CD).

           50fm
               select 50Xs (FM).

           75fm
               select 75Xs (FM).

           50kf
               select 50Xs (FM-KF).

           75kf
               select 75Xs (FM-KF).

   aeval
       Modify an audio signal according to the specified expressions.

       This filter accepts one or more expressions (one for each channel), which are evaluated
       and used to modify a corresponding audio signal.

       It accepts the following parameters:

       exprs
           Set the '|'-separated expressions list for each separate channel. If the number of
           input channels is greater than the number of expressions, the last specified
           expression is used for the remaining output channels.

       channel_layout, c
           Set output channel layout. If not specified, the channel layout is specified by the
           number of expressions. If set to same, it will use by default the same input channel
           layout.

       Each expression in exprs can contain the following constants and functions:

       ch  channel number of the current expression

       n   number of the evaluated sample, starting from 0

       s   sample rate

       t   time of the evaluated sample expressed in seconds

       nb_in_channels
       nb_out_channels
           input and output number of channels

       val(CH)
           the value of input channel with number CH

       Note: this filter is slow. For faster processing you should use a dedicated filter.

       Examples

       ·   Half volume:

                   aeval=val(ch)/2:c=same

       ·   Invert phase of the second channel:

                   aeval=val(0)|-val(1)

   afade
       Apply fade-in/out effect to input audio.

       A description of the accepted parameters follows.

       type, t
           Specify the effect type, can be either "in" for fade-in, or "out" for a fade-out
           effect. Default is "in".

       start_sample, ss
           Specify the number of the start sample for starting to apply the fade effect. Default
           is 0.

       nb_samples, ns
           Specify the number of samples for which the fade effect has to last. At the end of the
           fade-in effect the output audio will have the same volume as the input audio, at the
           end of the fade-out transition the output audio will be silence. Default is 44100.

       start_time, st
           Specify the start time of the fade effect. Default is 0.  The value must be specified
           as a time duration; see the Time duration section in the ffmpeg-utils(1) manual for
           the accepted syntax.  If set this option is used instead of start_sample.

       duration, d
           Specify the duration of the fade effect. See the Time duration section in the
           ffmpeg-utils(1) manual for the accepted syntax.  At the end of the fade-in effect the
           output audio will have the same volume as the input audio, at the end of the fade-out
           transition the output audio will be silence.  By default the duration is determined by
           nb_samples.  If set this option is used instead of nb_samples.

       curve
           Set curve for fade transition.

           It accepts the following values:

           tri select triangular, linear slope (default)

           qsin
               select quarter of sine wave

           hsin
               select half of sine wave

           esin
               select exponential sine wave

           log select logarithmic

           ipar
               select inverted parabola

           qua select quadratic

           cub select cubic

           squ select square root

           cbr select cubic root

           par select parabola

           exp select exponential

           iqsin
               select inverted quarter of sine wave

           ihsin
               select inverted half of sine wave

           dese
               select double-exponential seat

           desi
               select double-exponential sigmoid

       Examples

       ·   Fade in first 15 seconds of audio:

                   afade=t=in:ss=0:d=15

       ·   Fade out last 25 seconds of a 900 seconds audio:

                   afade=t=out:st=875:d=25

   afftfilt
       Apply arbitrary expressions to samples in frequency domain.

       real
           Set frequency domain real expression for each separate channel separated by '|'.
           Default is "1".  If the number of input channels is greater than the number of
           expressions, the last specified expression is used for the remaining output channels.

       imag
           Set frequency domain imaginary expression for each separate channel separated by '|'.
           If not set, real option is used.

           Each expression in real and imag can contain the following constants:

           sr  sample rate

           b   current frequency bin number

           nb  number of available bins

           ch  channel number of the current expression

           chs number of channels

           pts current frame pts

       win_size
           Set window size.

           It accepts the following values:

           w16
           w32
           w64
           w128
           w256
           w512
           w1024
           w2048
           w4096
           w8192
           w16384
           w32768
           w65536

           Default is "w4096"

       win_func
           Set window function. Default is "hann".

       overlap
           Set window overlap. If set to 1, the recommended overlap for selected window function
           will be picked. Default is 0.75.

       Examples

       ·   Leave almost only low frequencies in audio:

                   afftfilt="1-clip((b/nb)*b,0,1)"

   aformat
       Set output format constraints for the input audio. The framework will negotiate the most
       appropriate format to minimize conversions.

       It accepts the following parameters:

       sample_fmts
           A '|'-separated list of requested sample formats.

       sample_rates
           A '|'-separated list of requested sample rates.

       channel_layouts
           A '|'-separated list of requested channel layouts.

           See the Channel Layout section in the ffmpeg-utils(1) manual for the required syntax.

       If a parameter is omitted, all values are allowed.

       Force the output to either unsigned 8-bit or signed 16-bit stereo

               aformat=sample_fmts=u8|s16:channel_layouts=stereo

   agate
       A gate is mainly used to reduce lower parts of a signal. This kind of signal processing
       reduces disturbing noise between useful signals.

       Gating is done by detecting the volume below a chosen level threshold and dividing it by
       the factor set with ratio. The bottom of the noise floor is set via range. Because an
       exact manipulation of the signal would cause distortion of the waveform the reduction can
       be levelled over time. This is done by setting attack and release.

       attack determines how long the signal has to fall below the threshold before any reduction
       will occur and release sets the time the signal has to rise above the threshold to reduce
       the reduction again.  Shorter signals than the chosen attack time will be left untouched.

       level_in
           Set input level before filtering.  Default is 1. Allowed range is from 0.015625 to 64.

       range
           Set the level of gain reduction when the signal is below the threshold.  Default is
           0.06125. Allowed range is from 0 to 1.

       threshold
           If a signal rises above this level the gain reduction is released.  Default is 0.125.
           Allowed range is from 0 to 1.

       ratio
           Set a ratio by which the signal is reduced.  Default is 2. Allowed range is from 1 to
           9000.

       attack
           Amount of milliseconds the signal has to rise above the threshold before gain
           reduction stops.  Default is 20 milliseconds. Allowed range is from 0.01 to 9000.

       release
           Amount of milliseconds the signal has to fall below the threshold before the reduction
           is increased again. Default is 250 milliseconds.  Allowed range is from 0.01 to 9000.

       makeup
           Set amount of amplification of signal after processing.  Default is 1. Allowed range
           is from 1 to 64.

       knee
           Curve the sharp knee around the threshold to enter gain reduction more softly.
           Default is 2.828427125. Allowed range is from 1 to 8.

       detection
           Choose if exact signal should be taken for detection or an RMS like one.  Default is
           "rms". Can be "peak" or "rms".

       link
           Choose if the average level between all channels or the louder channel affects the
           reduction.  Default is "average". Can be "average" or "maximum".

   alimiter
       The limiter prevents an input signal from rising over a desired threshold.  This limiter
       uses lookahead technology to prevent your signal from distorting.  It means that there is
       a small delay after the signal is processed. Keep in mind that the delay it produces is
       the attack time you set.

       The filter accepts the following options:

       level_in
           Set input gain. Default is 1.

       level_out
           Set output gain. Default is 1.

       limit
           Don't let signals above this level pass the limiter. Default is 1.

       attack
           The limiter will reach its attenuation level in this amount of time in milliseconds.
           Default is 5 milliseconds.

       release
           Come back from limiting to attenuation 1.0 in this amount of milliseconds.  Default is
           50 milliseconds.

       asc When gain reduction is always needed ASC takes care of releasing to an average
           reduction level rather than reaching a reduction of 0 in the release time.

       asc_level
           Select how much the release time is affected by ASC, 0 means nearly no changes in
           release time while 1 produces higher release times.

       level
           Auto level output signal. Default is enabled.  This normalizes audio back to 0dB if
           enabled.

       Depending on picked setting it is recommended to upsample input 2x or 4x times with
       aresample before applying this filter.

   allpass
       Apply a two-pole all-pass filter with central frequency (in Hz) frequency, and filter-
       width width.  An all-pass filter changes the audio's frequency to phase relationship
       without changing its frequency to amplitude relationship.

       The filter accepts the following options:

       frequency, f
           Set frequency in Hz.

       width_type
           Set method to specify band-width of filter.

           h   Hz

           q   Q-Factor

           o   octave

           s   slope

       width, w
           Specify the band-width of a filter in width_type units.

   aloop
       Loop audio samples.

       The filter accepts the following options:

       loop
           Set the number of loops.

       size
           Set maximal number of samples.

       start
           Set first sample of loop.

   amerge
       Merge two or more audio streams into a single multi-channel stream.

       The filter accepts the following options:

       inputs
           Set the number of inputs. Default is 2.

       If the channel layouts of the inputs are disjoint, and therefore compatible, the channel
       layout of the output will be set accordingly and the channels will be reordered as
       necessary. If the channel layouts of the inputs are not disjoint, the output will have all
       the channels of the first input then all the channels of the second input, in that order,
       and the channel layout of the output will be the default value corresponding to the total
       number of channels.

       For example, if the first input is in 2.1 (FL+FR+LF) and the second input is FC+BL+BR,
       then the output will be in 5.1, with the channels in the following order: a1, a2, b1, a3,
       b2, b3 (a1 is the first channel of the first input, b1 is the first channel of the second
       input).

       On the other hand, if both input are in stereo, the output channels will be in the default
       order: a1, a2, b1, b2, and the channel layout will be arbitrarily set to 4.0, which may or
       may not be the expected value.

       All inputs must have the same sample rate, and format.

       If inputs do not have the same duration, the output will stop with the shortest.

       Examples

       ·   Merge two mono files into a stereo stream:

                   amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge

       ·   Multiple merges assuming 1 video stream and 6 audio streams in input.mkv:

                   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

   amix
       Mixes multiple audio inputs into a single output.

       Note that this filter only supports float samples (the amerge and pan audio filters
       support many formats). If the amix input has integer samples then aresample will be
       automatically inserted to perform the conversion to float samples.

       For example

               ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT

       will mix 3 input audio streams to a single output with the same duration as the first
       input and a dropout transition time of 3 seconds.

       It accepts the following parameters:

       inputs
           The number of inputs. If unspecified, it defaults to 2.

       duration
           How to determine the end-of-stream.

           longest
               The duration of the longest input. (default)

           shortest
               The duration of the shortest input.

           first
               The duration of the first input.

       dropout_transition
           The transition time, in seconds, for volume renormalization when an input stream ends.
           The default value is 2 seconds.

   anequalizer
       High-order parametric multiband equalizer for each channel.

       It accepts the following parameters:

       params
           This option string is in format: "cchn f=cf w=w g=g t=f | ..."  Each equalizer band is
           separated by '|'.

           chn Set channel number to which equalization will be applied.  If input doesn't have
               that channel the entry is ignored.

           f   Set central frequency for band.  If input doesn't have that frequency the entry is
               ignored.

           w   Set band width in hertz.

           g   Set band gain in dB.

           t   Set filter type for band, optional, can be:

               0   Butterworth, this is default.

               1   Chebyshev type 1.

               2   Chebyshev type 2.

       curves
           With this option activated frequency response of anequalizer is displayed in video
           stream.

       size
           Set video stream size. Only useful if curves option is activated.

       mgain
           Set max gain that will be displayed. Only useful if curves option is activated.
           Setting this to a reasonable value makes it possible to display gain which is derived
           from neighbour bands which are too close to each other and thus produce higher gain
           when both are activated.

       fscale
           Set frequency scale used to draw frequency response in video output.  Can be linear or
           logarithmic. Default is logarithmic.

       colors
           Set color for each channel curve which is going to be displayed in video stream.  This
           is list of color names separated by space or by '|'.  Unrecognised or missing colors
           will be replaced by white color.

       Examples

       ·   Lower gain by 10 of central frequency 200Hz and width 100 Hz for first 2 channels
           using Chebyshev type 1 filter:

                   anequalizer=c0 f=200 w=100 g=-10 t=1|c1 f=200 w=100 g=-10 t=1

       Commands

       This filter supports the following commands:

       change
           Alter existing filter parameters.  Syntax for the commands is :
           "fN|f=freq|w=width|g=gain"

           fN is existing filter number, starting from 0, if no such filter is available error is
           returned.  freq set new frequency parameter.  width set new width parameter in herz.
           gain set new gain parameter in dB.

           Full filter invocation with asendcmd may look like this: asendcmd=c='4.0 anequalizer
           change 0|f=200|w=50|g=1',anequalizer=...

   anull
       Pass the audio source unchanged to the output.

   apad
       Pad the end of an audio stream with silence.

       This can be used together with ffmpeg -shortest to extend audio streams to the same length
       as the video stream.

       A description of the accepted options follows.

       packet_size
           Set silence packet size. Default value is 4096.

       pad_len
           Set the number of samples of silence to add to the end. After the value is reached,
           the stream is terminated. This option is mutually exclusive with whole_len.

       whole_len
           Set the minimum total number of samples in the output audio stream. If the value is
           longer than the input audio length, silence is added to the end, until the value is
           reached. This option is mutually exclusive with pad_len.

       If neither the pad_len nor the whole_len option is set, the filter will add silence to the
       end of the input stream indefinitely.

       Examples

       ·   Add 1024 samples of silence to the end of the input:

                   apad=pad_len=1024

       ·   Make sure the audio output will contain at least 10000 samples, pad the input with
           silence if required:

                   apad=whole_len=10000

       ·   Use ffmpeg to pad the audio input with silence, so that the video stream will always
           result the shortest and will be converted until the end in the output file when using
           the shortest option:

                   ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT

   aphaser
       Add a phasing effect to the input audio.

       A phaser filter creates series of peaks and troughs in the frequency spectrum.  The
       position of the peaks and troughs are modulated so that they vary over time, creating a
       sweeping effect.

       A description of the accepted parameters follows.

       in_gain
           Set input gain. Default is 0.4.

       out_gain
           Set output gain. Default is 0.74

       delay
           Set delay in milliseconds. Default is 3.0.

       decay
           Set decay. Default is 0.4.

       speed
           Set modulation speed in Hz. Default is 0.5.

       type
           Set modulation type. Default is triangular.

           It accepts the following values:

           triangular, t
           sinusoidal, s

   apulsator
       Audio pulsator is something between an autopanner and a tremolo.  But it can produce funny
       stereo effects as well. Pulsator changes the volume of the left and right channel based on
       a LFO (low frequency oscillator) with different waveforms and shifted phases.  This filter
       have the ability to define an offset between left and right channel. An offset of 0 means
       that both LFO shapes match each other.  The left and right channel are altered equally - a
       conventional tremolo.  An offset of 50% means that the shape of the right channel is
       exactly shifted in phase (or moved backwards about half of the frequency) - pulsator acts
       as an autopanner. At 1 both curves match again. Every setting in between moves the phase
       shift gapless between all stages and produces some "bypassing" sounds with sine and
       triangle waveforms. The more you set the offset near 1 (starting from the 0.5) the faster
       the signal passes from the left to the right speaker.

       The filter accepts the following options:

       level_in
           Set input gain. By default it is 1. Range is [0.015625 - 64].

       level_out
           Set output gain. By default it is 1. Range is [0.015625 - 64].

       mode
           Set waveform shape the LFO will use. Can be one of: sine, triangle, square, sawup or
           sawdown. Default is sine.

       amount
           Set modulation. Define how much of original signal is affected by the LFO.

       offset_l
           Set left channel offset. Default is 0. Allowed range is [0 - 1].

       offset_r
           Set right channel offset. Default is 0.5. Allowed range is [0 - 1].

       width
           Set pulse width. Default is 1. Allowed range is [0 - 2].

       timing
           Set possible timing mode. Can be one of: bpm, ms or hz. Default is hz.

       bpm Set bpm. Default is 120. Allowed range is [30 - 300]. Only used if timing is set to
           bpm.

       ms  Set ms. Default is 500. Allowed range is [10 - 2000]. Only used if timing is set to
           ms.

       hz  Set frequency in Hz. Default is 2. Allowed range is [0.01 - 100]. Only used if timing
           is set to hz.

   aresample
       Resample the input audio to the specified parameters, using the libswresample library. If
       none are specified then the filter will automatically convert between its input and
       output.

       This filter is also able to stretch/squeeze the audio data to make it match the timestamps
       or to inject silence / cut out audio to make it match the timestamps, do a combination of
       both or do neither.

       The filter accepts the syntax [sample_rate:]resampler_options, where sample_rate expresses
       a sample rate and resampler_options is a list of key=value pairs, separated by ":". See
       the the "Resampler Options" section in the ffmpeg-resampler(1) manual for the complete
       list of supported options.

       Examples

       ·   Resample the input audio to 44100Hz:

                   aresample=44100

       ·   Stretch/squeeze samples to the given timestamps, with a maximum of 1000 samples per
           second compensation:

                   aresample=async=1000

   areverse
       Reverse an audio clip.

       Warning: This filter requires memory to buffer the entire clip, so trimming is suggested.

       Examples

       ·   Take the first 5 seconds of a clip, and reverse it.

                   atrim=end=5,areverse

   asetnsamples
       Set the number of samples per each output audio frame.

       The last output packet may contain a different number of samples, as the filter will flush
       all the remaining samples when the input audio signals its end.

       The filter accepts the following options:

       nb_out_samples, n
           Set the number of frames per each output audio frame. The number is intended as the
           number of samples per each channel.  Default value is 1024.

       pad, p
           If set to 1, the filter will pad the last audio frame with zeroes, so that the last
           frame will contain the same number of samples as the previous ones. Default value is
           1.

       For example, to set the number of per-frame samples to 1234 and disable padding for the
       last frame, use:

               asetnsamples=n=1234:p=0

   asetrate
       Set the sample rate without altering the PCM data.  This will result in a change of speed
       and pitch.

       The filter accepts the following options:

       sample_rate, r
           Set the output sample rate. Default is 44100 Hz.

   ashowinfo
       Show a line containing various information for each input audio frame.  The input audio is
       not modified.

       The shown line contains a sequence of key/value pairs of the form key:value.

       The following values are shown in the output:

       n   The (sequential) number of the input frame, starting from 0.

       pts The presentation timestamp of the input frame, in time base units; the time base
           depends on the filter input pad, and is usually 1/sample_rate.

       pts_time
           The presentation timestamp of the input frame in seconds.

       pos position of the frame in the input stream, -1 if this information in unavailable
           and/or meaningless (for example in case of synthetic audio)

       fmt The sample format.

       chlayout
           The channel layout.

       rate
           The sample rate for the audio frame.

       nb_samples
           The number of samples (per channel) in the frame.

       checksum
           The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio,
           the data is treated as if all the planes were concatenated.

       plane_checksums
           A list of Adler-32 checksums for each data plane.

   astats
       Display time domain statistical information about the audio channels.  Statistics are
       calculated and displayed for each audio channel and, where applicable, an overall figure
       is also given.

       It accepts the following option:

       length
           Short window length in seconds, used for peak and trough RMS measurement.  Default is
           0.05 (50 milliseconds). Allowed range is "[0.1 - 10]".

       metadata
           Set metadata injection. All the metadata keys are prefixed with "lavfi.astats.X",
           where "X" is channel number starting from 1 or string "Overall". Default is disabled.

           Available keys for each channel are: DC_offset Min_level Max_level Min_difference
           Max_difference Mean_difference Peak_level RMS_peak RMS_trough Crest_factor Flat_factor
           Peak_count Bit_depth

           and for Overall: DC_offset Min_level Max_level Min_difference Max_difference
           Mean_difference Peak_level RMS_level RMS_peak RMS_trough Flat_factor Peak_count
           Bit_depth Number_of_samples

           For example full key look like this "lavfi.astats.1.DC_offset" or this
           "lavfi.astats.Overall.Peak_count".

           For description what each key means read below.

       reset
           Set number of frame after which stats are going to be recalculated.  Default is
           disabled.

       A description of each shown parameter follows:

       DC offset
           Mean amplitude displacement from zero.

       Min level
           Minimal sample level.

       Max level
           Maximal sample level.

       Min difference
           Minimal difference between two consecutive samples.

       Max difference
           Maximal difference between two consecutive samples.

       Mean difference
           Mean difference between two consecutive samples.  The average of each difference
           between two consecutive samples.

       Peak level dB
       RMS level dB
           Standard peak and RMS level measured in dBFS.

       RMS peak dB
       RMS trough dB
           Peak and trough values for RMS level measured over a short window.

       Crest factor
           Standard ratio of peak to RMS level (note: not in dB).

       Flat factor
           Flatness (i.e. consecutive samples with the same value) of the signal at its peak
           levels (i.e. either Min level or Max level).

       Peak count
           Number of occasions (not the number of samples) that the signal attained either Min
           level or Max level.

       Bit depth
           Overall bit depth of audio. Number of bits used for each sample.

   atempo
       Adjust audio tempo.

       The filter accepts exactly one parameter, the audio tempo. If not specified then the
       filter will assume nominal 1.0 tempo. Tempo must be in the [0.5, 2.0] range.

       Examples

       ·   Slow down audio to 80% tempo:

                   atempo=0.8

       ·   To speed up audio to 125% tempo:

                   atempo=1.25

   atrim
       Trim the input so that the output contains one continuous subpart of the input.

       It accepts the following parameters:

       start
           Timestamp (in seconds) of the start of the section to keep. I.e. the audio sample with
           the timestamp start will be the first sample in the output.

       end Specify time of the first audio sample that will be dropped, i.e. the audio sample
           immediately preceding the one with the timestamp end will be the last sample in the
           output.

       start_pts
           Same as start, except this option sets the start timestamp in samples instead of
           seconds.

       end_pts
           Same as end, except this option sets the end timestamp in samples instead of seconds.

       duration
           The maximum duration of the output in seconds.

       start_sample
           The number of the first sample that should be output.

       end_sample
           The number of the first sample that should be dropped.

       start, end, and duration are expressed as time duration specifications; see the Time
       duration section in the ffmpeg-utils(1) manual.

       Note that the first two sets of the start/end options and the duration option look at the
       frame timestamp, while the _sample options simply count the samples that pass through the
       filter. So start/end_pts and start/end_sample will give different results when the
       timestamps are wrong, inexact or do not start at zero. Also note that this filter does not
       modify the timestamps. If you wish to have the output timestamps start at zero, insert the
       asetpts filter after the atrim filter.

       If multiple start or end options are set, this filter tries to be greedy and keep all
       samples that match at least one of the specified constraints. To keep only the part that
       matches all the constraints at once, chain multiple atrim filters.

       The defaults are such that all the input is kept. So it is possible to set e.g.  just the
       end values to keep everything before the specified time.

       Examples:

       ·   Drop everything except the second minute of input:

                   ffmpeg -i INPUT -af atrim=60:120

       ·   Keep only the first 1000 samples:

                   ffmpeg -i INPUT -af atrim=end_sample=1000

   bandpass
       Apply a two-pole Butterworth band-pass filter with central frequency frequency, and
       (3dB-point) band-width width.  The csg option selects a constant skirt gain (peak gain =
       Q) instead of the default: constant 0dB peak gain.  The filter roll off at 6dB per octave
       (20dB per decade).

       The filter accepts the following options:

       frequency, f
           Set the filter's central frequency. Default is 3000.

       csg Constant skirt gain if set to 1. Defaults to 0.

       width_type
           Set method to specify band-width of filter.

           h   Hz

           q   Q-Factor

           o   octave

           s   slope

       width, w
           Specify the band-width of a filter in width_type units.

   bandreject
       Apply a two-pole Butterworth band-reject filter with central frequency frequency, and
       (3dB-point) band-width width.  The filter roll off at 6dB per octave (20dB per decade).

       The filter accepts the following options:

       frequency, f
           Set the filter's central frequency. Default is 3000.

       width_type
           Set method to specify band-width of filter.

           h   Hz

           q   Q-Factor

           o   octave

           s   slope

       width, w
           Specify the band-width of a filter in width_type units.

   bass
       Boost or cut the bass (lower) frequencies of the audio using a two-pole shelving filter
       with a response similar to that of a standard hi-fi's tone-controls. This is also known as
       shelving equalisation (EQ).

       The filter accepts the following options:

       gain, g
           Give the gain at 0 Hz. Its useful range is about -20 (for a large cut) to +20 (for a
           large boost).  Beware of clipping when using a positive gain.

       frequency, f
           Set the filter's central frequency and so can be used to extend or reduce the
           frequency range to be boosted or cut.  The default value is 100 Hz.

       width_type
           Set method to specify band-width of filter.

           h   Hz

           q   Q-Factor

           o   octave

           s   slope

       width, w
           Determine how steep is the filter's shelf transition.

   biquad
       Apply a biquad IIR filter with the given coefficients.  Where b0, b1, b2 and a0, a1, a2
       are the numerator and denominator coefficients respectively.

   bs2b
       Bauer stereo to binaural transformation, which improves headphone listening of stereo
       audio records.

       It accepts the following parameters:

       profile
           Pre-defined crossfeed level.

           default
               Default level (fcut=700, feed=50).

           cmoy
               Chu Moy circuit (fcut=700, feed=60).

           jmeier
               Jan Meier circuit (fcut=650, feed=95).

       fcut
           Cut frequency (in Hz).

       feed
           Feed level (in Hz).

   channelmap
       Remap input channels to new locations.

       It accepts the following parameters:

       map Map channels from input to output. The argument is a '|'-separated list of mappings,
           each in the "in_channel-out_channel" or in_channel form. in_channel can be either the
           name of the input channel (e.g. FL for front left) or its index in the input channel
           layout.  out_channel is the name of the output channel or its index in the output
           channel layout. If out_channel is not given then it is implicitly an index, starting
           with zero and increasing by one for each mapping.

       channel_layout
           The channel layout of the output stream.

       If no mapping is present, the filter will implicitly map input channels to output
       channels, preserving indices.

       For example, assuming a 5.1+downmix input MOV file,

               ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav

       will create an output WAV file tagged as stereo from the downmix channels of the input.

       To fix a 5.1 WAV improperly encoded in AAC's native channel order

               ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav

   channelsplit
       Split each channel from an input audio stream into a separate output stream.

       It accepts the following parameters:

       channel_layout
           The channel layout of the input stream. The default is "stereo".

       For example, assuming a stereo input MP3 file,

               ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv

       will create an output Matroska file with two audio streams, one containing only the left
       channel and the other the right channel.

       Split a 5.1 WAV file into per-channel files:

               ffmpeg -i in.wav -filter_complex
               'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
               -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
               front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
               side_right.wav

   chorus
       Add a chorus effect to the audio.

       Can make a single vocal sound like a chorus, but can also be applied to instrumentation.

       Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
       constant, with chorus, it is varied using using sinusoidal or triangular modulation.  The
       modulation depth defines the range the modulated delay is played before or after the
       delay. Hence the delayed sound will sound slower or faster, that is the delayed sound
       tuned around the original one, like in a chorus where some vocals are slightly off key.

       It accepts the following parameters:

       in_gain
           Set input gain. Default is 0.4.

       out_gain
           Set output gain. Default is 0.4.

       delays
           Set delays. A typical delay is around 40ms to 60ms.

       decays
           Set decays.

       speeds
           Set speeds.

       depths
           Set depths.

       Examples

       ·   A single delay:

                   chorus=0.7:0.9:55:0.4:0.25:2

       ·   Two delays:

                   chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3

       ·   Fuller sounding chorus with three delays:

                   chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3

   compand
       Compress or expand the audio's dynamic range.

       It accepts the following parameters:

       attacks
       decays
           A list of times in seconds for each channel over which the instantaneous level of the
           input signal is averaged to determine its volume. attacks refers to increase of volume
           and decays refers to decrease of volume. For most situations, the attack time
           (response to the audio getting louder) should be shorter than the decay time, because
           the human ear is more sensitive to sudden loud audio than sudden soft audio. A typical
           value for attack is 0.3 seconds and a typical value for decay is 0.8 seconds.  If
           specified number of attacks & decays is lower than number of channels, the last set
           attack/decay will be used for all remaining channels.

       points
           A list of points for the transfer function, specified in dB relative to the maximum
           possible signal amplitude. Each key points list must be defined using the following
           syntax: "x0/y0|x1/y1|x2/y2|...." or "x0/y0 x1/y1 x2/y2 ...."

           The input values must be in strictly increasing order but the transfer function does
           not have to be monotonically rising. The point "0/0" is assumed but may be overridden
           (by "0/out-dBn"). Typical values for the transfer function are "-70/-70|-60/-20".

       soft-knee
           Set the curve radius in dB for all joints. It defaults to 0.01.

       gain
           Set the additional gain in dB to be applied at all points on the transfer function.
           This allows for easy adjustment of the overall gain.  It defaults to 0.

       volume
           Set an initial volume, in dB, to be assumed for each channel when filtering starts.
           This permits the user to supply a nominal level initially, so that, for example, a
           very large gain is not applied to initial signal levels before the companding has
           begun to operate. A typical value for audio which is initially quiet is -90 dB. It
           defaults to 0.

       delay
           Set a delay, in seconds. The input audio is analyzed immediately, but audio is delayed
           before being fed to the volume adjuster. Specifying a delay approximately equal to the
           attack/decay times allows the filter to effectively operate in predictive rather than
           reactive mode. It defaults to 0.

       Examples

       ·   Make music with both quiet and loud passages suitable for listening to in a noisy
           environment:

                   compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2

           Another example for audio with whisper and explosion parts:

                   compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0

       ·   A noise gate for when the noise is at a lower level than the signal:

                   compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1

       ·   Here is another noise gate, this time for when the noise is at a higher level than the
           signal (making it, in some ways, similar to squelch):

                   compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1

       ·   2:1 compression starting at -6dB:

                   compand=points=-80/-80|-6/-6|0/-3.8|20/3.5

       ·   2:1 compression starting at -9dB:

                   compand=points=-80/-80|-9/-9|0/-5.3|20/2.9

       ·   2:1 compression starting at -12dB:

                   compand=points=-80/-80|-12/-12|0/-6.8|20/1.9

       ·   2:1 compression starting at -18dB:

                   compand=points=-80/-80|-18/-18|0/-9.8|20/0.7

       ·   3:1 compression starting at -15dB:

                   compand=points=-80/-80|-15/-15|0/-10.8|20/-5.2

       ·   Compressor/Gate:

                   compand=points=-80/-105|-62/-80|-15.4/-15.4|0/-12|20/-7.6

       ·   Expander:

                   compand=attacks=0:points=-80/-169|-54/-80|-49.5/-64.6|-41.1/-41.1|-25.8/-15|-10.8/-4.5|0/0|20/8.3

       ·   Hard limiter at -6dB:

                   compand=attacks=0:points=-80/-80|-6/-6|20/-6

       ·   Hard limiter at -12dB:

                   compand=attacks=0:points=-80/-80|-12/-12|20/-12

       ·   Hard noise gate at -35 dB:

                   compand=attacks=0:points=-80/-115|-35.1/-80|-35/-35|20/20

       ·   Soft limiter:

                   compand=attacks=0:points=-80/-80|-12.4/-12.4|-6/-8|0/-6.8|20/-2.8

   compensationdelay
       Compensation Delay Line is a metric based delay to compensate differing positions of
       microphones or speakers.

       For example, you have recorded guitar with two microphones placed in different location.
       Because the front of sound wave has fixed speed in normal conditions, the phasing of
       microphones can vary and depends on their location and interposition. The best sound mix
       can be achieved when these microphones are in phase (synchronized). Note that distance of
       ~30 cm between microphones makes one microphone to capture signal in antiphase to another
       microphone. That makes the final mix sounding moody.  This filter helps to solve phasing
       problems by adding different delays to each microphone track and make them synchronized.

       The best result can be reached when you take one track as base and synchronize other
       tracks one by one with it.  Remember that synchronization/delay tolerance depends on
       sample rate, too.  Higher sample rates will give more tolerance.

       It accepts the following parameters:

       mm  Set millimeters distance. This is compensation distance for fine tuning.  Default is
           0.

       cm  Set cm distance. This is compensation distance for tightening distance setup.  Default
           is 0.

       m   Set meters distance. This is compensation distance for hard distance setup.  Default
           is 0.

       dry Set dry amount. Amount of unprocessed (dry) signal.  Default is 0.

       wet Set wet amount. Amount of processed (wet) signal.  Default is 1.

       temp
           Set temperature degree in Celsius. This is the temperature of the environment.
           Default is 20.

   crystalizer
       Simple algorithm to expand audio dynamic range.

       The filter accepts the following options:

       i   Sets the intensity of effect (default: 2.0). Must be in range between 0.0 (unchanged
           sound) to 10.0 (maximum effect).

       c   Enable clipping. By default is enabled.

   dcshift
       Apply a DC shift to the audio.

       This can be useful to remove a DC offset (caused perhaps by a hardware problem in the
       recording chain) from the audio. The effect of a DC offset is reduced headroom and hence
       volume. The astats filter can be used to determine if a signal has a DC offset.

       shift
           Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift the
           audio.

       limitergain
           Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is used to
           prevent clipping.

   dynaudnorm
       Dynamic Audio Normalizer.

       This filter applies a certain amount of gain to the input audio in order to bring its peak
       magnitude to a target level (e.g. 0 dBFS). However, in contrast to more "simple"
       normalization algorithms, the Dynamic Audio Normalizer *dynamically* re-adjusts the gain
       factor to the input audio.  This allows for applying extra gain to the "quiet" sections of
       the audio while avoiding distortions or clipping the "loud" sections. In other words: The
       Dynamic Audio Normalizer will "even out" the volume of quiet and loud sections, in the
       sense that the volume of each section is brought to the same target level. Note, however,
       that the Dynamic Audio Normalizer achieves this goal *without* applying "dynamic range
       compressing". It will retain 100% of the dynamic range *within* each section of the audio
       file.

       f   Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.  Default
           is 500 milliseconds.  The Dynamic Audio Normalizer processes the input audio in small
           chunks, referred to as frames. This is required, because a peak magnitude has no
           meaning for just a single sample value. Instead, we need to determine the peak
           magnitude for a contiguous sequence of sample values. While a "standard" normalizer
           would simply use the peak magnitude of the complete file, the Dynamic Audio Normalizer
           determines the peak magnitude individually for each frame. The length of a frame is
           specified in milliseconds. By default, the Dynamic Audio Normalizer uses a frame
           length of 500 milliseconds, which has been found to give good results with most files.
           Note that the exact frame length, in number of samples, will be determined
           automatically, based on the sampling rate of the individual input audio file.

       g   Set the Gaussian filter window size. In range from 3 to 301, must be odd number.
           Default is 31.  Probably the most important parameter of the Dynamic Audio Normalizer
           is the "window size" of the Gaussian smoothing filter. The filter's window size is
           specified in frames, centered around the current frame. For the sake of simplicity,
           this must be an odd number. Consequently, the default value of 31 takes into account
           the current frame, as well as the 15 preceding frames and the 15 subsequent frames.
           Using a larger window results in a stronger smoothing effect and thus in less gain
           variation, i.e. slower gain adaptation. Conversely, using a smaller window results in
           a weaker smoothing effect and thus in more gain variation, i.e. faster gain
           adaptation.  In other words, the more you increase this value, the more the Dynamic
           Audio Normalizer will behave like a "traditional" normalization filter. On the
           contrary, the more you decrease this value, the more the Dynamic Audio Normalizer will
           behave like a dynamic range compressor.

       p   Set the target peak value. This specifies the highest permissible magnitude level for
           the normalized audio input. This filter will try to approach the target peak magnitude
           as closely as possible, but at the same time it also makes sure that the normalized
           signal will never exceed the peak magnitude.  A frame's maximum local gain factor is
           imposed directly by the target peak magnitude. The default value is 0.95 and thus
           leaves a headroom of 5%*.  It is not recommended to go above this value.

       m   Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.  The Dynamic
           Audio Normalizer determines the maximum possible (local) gain factor for each input
           frame, i.e. the maximum gain factor that does not result in clipping or distortion.
           The maximum gain factor is determined by the frame's highest magnitude sample.
           However, the Dynamic Audio Normalizer additionally bounds the frame's maximum gain
           factor by a predetermined (global) maximum gain factor. This is done in order to avoid
           excessive gain factors in "silent" or almost silent frames. By default, the maximum
           gain factor is 10.0, For most inputs the default value should be sufficient and it
           usually is not recommended to increase this value. Though, for input with an extremely
           low overall volume level, it may be necessary to allow even higher gain factors. Note,
           however, that the Dynamic Audio Normalizer does not simply apply a "hard" threshold
           (i.e. cut off values above the threshold).  Instead, a "sigmoid" threshold function
           will be applied. This way, the gain factors will smoothly approach the threshold
           value, but never exceed that value.

       r   Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.  By default,
           the Dynamic Audio Normalizer performs "peak" normalization.  This means that the
           maximum local gain factor for each frame is defined (only) by the frame's highest
           magnitude sample. This way, the samples can be amplified as much as possible without
           exceeding the maximum signal level, i.e. without clipping. Optionally, however, the
           Dynamic Audio Normalizer can also take into account the frame's root mean square,
           abbreviated RMS. In electrical engineering, the RMS is commonly used to determine the
           power of a time-varying signal. It is therefore considered that the RMS is a better
           approximation of the "perceived loudness" than just looking at the signal's peak
           magnitude. Consequently, by adjusting all frames to a constant RMS value, a uniform
           "perceived loudness" can be established. If a target RMS value has been specified, a
           frame's local gain factor is defined as the factor that would result in exactly that
           RMS value.  Note, however, that the maximum local gain factor is still restricted by
           the frame's highest magnitude sample, in order to prevent clipping.

       n   Enable channels coupling. By default is enabled.  By default, the Dynamic Audio
           Normalizer will amplify all channels by the same amount. This means the same gain
           factor will be applied to all channels, i.e.  the maximum possible gain factor is
           determined by the "loudest" channel.  However, in some recordings, it may happen that
           the volume of the different channels is uneven, e.g. one channel may be "quieter" than
           the other one(s).  In this case, this option can be used to disable the channel
           coupling. This way, the gain factor will be determined independently for each channel,
           depending only on the individual channel's highest magnitude sample. This allows for
           harmonizing the volume of the different channels.

       c   Enable DC bias correction. By default is disabled.  An audio signal (in the time
           domain) is a sequence of sample values.  In the Dynamic Audio Normalizer these sample
           values are represented in the -1.0 to 1.0 range, regardless of the original input
           format. Normally, the audio signal, or "waveform", should be centered around the zero
           point.  That means if we calculate the mean value of all samples in a file, or in a
           single frame, then the result should be 0.0 or at least very close to that value. If,
           however, there is a significant deviation of the mean value from 0.0, in either
           positive or negative direction, this is referred to as a DC bias or DC offset. Since a
           DC bias is clearly undesirable, the Dynamic Audio Normalizer provides optional DC bias
           correction.  With DC bias correction enabled, the Dynamic Audio Normalizer will
           determine the mean value, or "DC correction" offset, of each input frame and subtract
           that value from all of the frame's sample values which ensures those samples are
           centered around 0.0 again. Also, in order to avoid "gaps" at the frame boundaries, the
           DC correction offset values will be interpolated smoothly between neighbouring frames.

       b   Enable alternative boundary mode. By default is disabled.  The Dynamic Audio
           Normalizer takes into account a certain neighbourhood around each frame. This includes
           the preceding frames as well as the subsequent frames. However, for the "boundary"
           frames, located at the very beginning and at the very end of the audio file, not all
           neighbouring frames are available. In particular, for the first few frames in the
           audio file, the preceding frames are not known. And, similarly, for the last few
           frames in the audio file, the subsequent frames are not known. Thus, the question
           arises which gain factors should be assumed for the missing frames in the "boundary"
           region. The Dynamic Audio Normalizer implements two modes to deal with this situation.
           The default boundary mode assumes a gain factor of exactly 1.0 for the missing frames,
           resulting in a smooth "fade in" and "fade out" at the beginning and at the end of the
           input, respectively.

       s   Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.  By default, the
           Dynamic Audio Normalizer does not apply "traditional" compression. This means that
           signal peaks will not be pruned and thus the full dynamic range will be retained
           within each local neighbourhood. However, in some cases it may be desirable to combine
           the Dynamic Audio Normalizer's normalization algorithm with a more "traditional"
           compression.  For this purpose, the Dynamic Audio Normalizer provides an optional
           compression (thresholding) function. If (and only if) the compression feature is
           enabled, all input frames will be processed by a soft knee thresholding function prior
           to the actual normalization process. Put simply, the thresholding function is going to
           prune all samples whose magnitude exceeds a certain threshold value.  However, the
           Dynamic Audio Normalizer does not simply apply a fixed threshold value. Instead, the
           threshold value will be adjusted for each individual frame.  In general, smaller
           parameters result in stronger compression, and vice versa.  Values below 3.0 are not
           recommended, because audible distortion may appear.

   earwax
       Make audio easier to listen to on headphones.

       This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio so that when
       listened to on headphones the stereo image is moved from inside your head (standard for
       headphones) to outside and in front of the listener (standard for speakers).

       Ported from SoX.

   equalizer
       Apply a two-pole peaking equalisation (EQ) filter. With this filter, the signal-level at
       and around a selected frequency can be increased or decreased, whilst (unlike bandpass and
       bandreject filters) that at all other frequencies is unchanged.

       In order to produce complex equalisation curves, this filter can be given several times,
       each with a different central frequency.

       The filter accepts the following options:

       frequency, f
           Set the filter's central frequency in Hz.

       width_type
           Set method to specify band-width of filter.

           h   Hz

           q   Q-Factor

           o   octave

           s   slope

       width, w
           Specify the band-width of a filter in width_type units.

       gain, g
           Set the required gain or attenuation in dB.  Beware of clipping when using a positive
           gain.

       Examples

       ·   Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:

                   equalizer=f=1000:width_type=h:width=200:g=-10

       ·   Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:

                   equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5

   extrastereo
       Linearly increases the difference between left and right channels which adds some sort of
       "live" effect to playback.

       The filter accepts the following options:

       m   Sets the difference coefficient (default: 2.5). 0.0 means mono sound (average of both
           channels), with 1.0 sound will be unchanged, with -1.0 left and right channels will be
           swapped.

       c   Enable clipping. By default is enabled.

   firequalizer
       Apply FIR Equalization using arbitrary frequency response.

       The filter accepts the following option:

       gain
           Set gain curve equation (in dB). The expression can contain variables:

           f   the evaluated frequency

           sr  sample rate

           ch  channel number, set to 0 when multichannels evaluation is disabled

           chid
               channel id, see libavutil/channel_layout.h, set to the first channel id when
               multichannels evaluation is disabled

           chs number of channels

           chlayout
               channel_layout, see libavutil/channel_layout.h

           and functions:

           gain_interpolate(f)
               interpolate gain on frequency f based on gain_entry

           cubic_interpolate(f)
               same as gain_interpolate, but smoother

           This option is also available as command. Default is gain_interpolate(f).

       gain_entry
           Set gain entry for gain_interpolate function. The expression can contain functions:

           entry(f, g)
               store gain entry at frequency f with value g

           This option is also available as command.

       delay
           Set filter delay in seconds. Higher value means more accurate.  Default is 0.01.

       accuracy
           Set filter accuracy in Hz. Lower value means more accurate.  Default is 5.

       wfunc
           Set window function. Acceptable values are:

           rectangular
               rectangular window, useful when gain curve is already smooth

           hann
               hann window (default)

           hamming
               hamming window

           blackman
               blackman window

           nuttall3
               3-terms continuous 1st derivative nuttall window

           mnuttall3
               minimum 3-terms discontinuous nuttall window

           nuttall
               4-terms continuous 1st derivative nuttall window

           bnuttall
               minimum 4-terms discontinuous nuttall (blackman-nuttall) window

           bharris
               blackman-harris window

           tukey
               tukey window

       fixed
           If enabled, use fixed number of audio samples. This improves speed when filtering with
           large delay. Default is disabled.

       multi
           Enable multichannels evaluation on gain. Default is disabled.

       zero_phase
           Enable zero phase mode by subtracting timestamp to compensate delay.  Default is
           disabled.

       scale
           Set scale used by gain. Acceptable values are:

           linlin
               linear frequency, linear gain

           linlog
               linear frequency, logarithmic (in dB) gain (default)

           loglin
               logarithmic (in octave scale where 20 Hz is 0) frequency, linear gain

           loglog
               logarithmic frequency, logarithmic gain

       dumpfile
           Set file for dumping, suitable for gnuplot.

       dumpscale
           Set scale for dumpfile. Acceptable values are same with scale option.  Default is
           linlog.

       fft2
           Enable 2-channel convolution using complex FFT. This improves speed significantly.
           Default is disabled.

       Examples

       ·   lowpass at 1000 Hz:

                   firequalizer=gain='if(lt(f,1000), 0, -INF)'

       ·   lowpass at 1000 Hz with gain_entry:

                   firequalizer=gain_entry='entry(1000,0); entry(1001, -INF)'

       ·   custom equalization:

                   firequalizer=gain_entry='entry(100,0); entry(400, -4); entry(1000, -6); entry(2000, 0)'

       ·   higher delay with zero phase to compensate delay:

                   firequalizer=delay=0.1:fixed=on:zero_phase=on

       ·   lowpass on left channel, highpass on right channel:

                   firequalizer=gain='if(eq(chid,1), gain_interpolate(f), if(eq(chid,2), gain_interpolate(1e6+f), 0))'
                   :gain_entry='entry(1000, 0); entry(1001,-INF); entry(1e6+1000,0)':multi=on

   flanger
       Apply a flanging effect to the audio.

       The filter accepts the following options:

       delay
           Set base delay in milliseconds. Range from 0 to 30. Default value is 0.

       depth
           Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.

       regen
           Set percentage regeneration (delayed signal feedback). Range from -95 to 95.  Default
           value is 0.

       width
           Set percentage of delayed signal mixed with original. Range from 0 to 100.  Default
           value is 71.

       speed
           Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.

       shape
           Set swept wave shape, can be triangular or sinusoidal.  Default value is sinusoidal.

       phase
           Set swept wave percentage-shift for multi channel. Range from 0 to 100.  Default value
           is 25.

       interp
           Set delay-line interpolation, linear or quadratic.  Default is linear.

   hdcd
       Decodes High Definition Compatible Digital (HDCD) data. A 16-bit PCM stream with embedded
       HDCD codes is expanded into a 20-bit PCM stream.

       The filter supports the Peak Extend and Low-level Gain Adjustment features of HDCD, and
       detects the Transient Filter flag.

               ffmpeg -i HDCD16.flac -af hdcd OUT24.flac

       When using the filter with wav, note the default encoding for wav is 16-bit, so the
       resulting 20-bit stream will be truncated back to 16-bit. Use something like -acodec
       pcm_s24le after the filter to get 24-bit PCM output.

               ffmpeg -i HDCD16.wav -af hdcd OUT16.wav
               ffmpeg -i HDCD16.wav -af hdcd -acodec pcm_s24le OUT24.wav

       The filter accepts the following options:

       disable_autoconvert
           Disable any automatic format conversion or resampling in the filter graph.

       process_stereo
           Process the stereo channels together. If target_gain does not match between channels,
           consider it invalid and use the last valid target_gain.

       cdt_ms
           Set the code detect timer period in ms.

       force_pe
           Always extend peaks above -3dBFS even if PE isn't signaled.

       analyze_mode
           Replace audio with a solid tone and adjust the amplitude to signal some specific
           aspect of the decoding process. The output file can be loaded in an audio editor
           alongside the original to aid analysis.

           "analyze_mode=pe:force_pe=true" can be used to see all samples above the PE level.

           Modes are:

           0, off
               Disabled

           1, lle
               Gain adjustment level at each sample

           2, pe
               Samples where peak extend occurs

           3, cdt
               Samples where the code detect timer is active

           4, tgm
               Samples where the target gain does not match between channels

   highpass
       Apply a high-pass filter with 3dB point frequency.  The filter can be either single-pole,
       or double-pole (the default).  The filter roll off at 6dB per pole per octave (20dB per
       pole per decade).

       The filter accepts the following options:

       frequency, f
           Set frequency in Hz. Default is 3000.

       poles, p
           Set number of poles. Default is 2.

       width_type
           Set method to specify band-width of filter.

           h   Hz

           q   Q-Factor

           o   octave

           s   slope

       width, w
           Specify the band-width of a filter in width_type units.  Applies only to double-pole
           filter.  The default is 0.707q and gives a Butterworth response.

   join
       Join multiple input streams into one multi-channel stream.

       It accepts the following parameters:

       inputs
           The number of input streams. It defaults to 2.

       channel_layout
           The desired output channel layout. It defaults to stereo.

       map Map channels from inputs to output. The argument is a '|'-separated list of mappings,
           each in the "input_idx.in_channel-out_channel" form. input_idx is the 0-based index of
           the input stream. in_channel can be either the name of the input channel (e.g. FL for
           front left) or its index in the specified input stream. out_channel is the name of the
           output channel.

       The filter will attempt to guess the mappings when they are not specified explicitly. It
       does so by first trying to find an unused matching input channel and if that fails it
       picks the first unused input channel.

       Join 3 inputs (with properly set channel layouts):

               ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT

       Build a 5.1 output from 6 single-channel streams:

               ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
               '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'
               out

   ladspa
       Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.

       To enable compilation of this filter you need to configure FFmpeg with "--enable-ladspa".

       file, f
           Specifies the name of LADSPA plugin library to load. If the environment variable
           LADSPA_PATH is defined, the LADSPA plugin is searched in each one of the directories
           specified by the colon separated list in LADSPA_PATH, otherwise in the standard LADSPA
           paths, which are in this order: HOME/.ladspa/lib/, /usr/local/lib/ladspa/,
           /usr/lib/ladspa/.

       plugin, p
           Specifies the plugin within the library. Some libraries contain only one plugin, but
           others contain many of them. If this is not set filter will list all available plugins
           within the specified library.

       controls, c
           Set the '|' separated list of controls which are zero or more floating point values
           that determine the behavior of the loaded plugin (for example delay, threshold or
           gain).  Controls need to be defined using the following syntax:
           c0=value0|c1=value1|c2=value2|..., where valuei is the value set on the i-th control.
           Alternatively they can be also defined using the following syntax:
           value0|value1|value2|..., where valuei is the value set on the i-th control.  If
           controls is set to "help", all available controls and their valid ranges are printed.

       sample_rate, s
           Specify the sample rate, default to 44100. Only used if plugin have zero inputs.

       nb_samples, n
           Set the number of samples per channel per each output frame, default is 1024. Only
           used if plugin have zero inputs.

       duration, d
           Set the minimum duration of the sourced audio. See the Time duration section in the
           ffmpeg-utils(1) manual for the accepted syntax.  Note that the resulting duration may
           be greater than the specified duration, as the generated audio is always cut at the
           end of a complete frame.  If not specified, or the expressed duration is negative, the
           audio is supposed to be generated forever.  Only used if plugin have zero inputs.

       Examples

       ·   List all available plugins within amp (LADSPA example plugin) library:

                   ladspa=file=amp

       ·   List all available controls and their valid ranges for "vcf_notch" plugin from "VCF"
           library:

                   ladspa=f=vcf:p=vcf_notch:c=help

       ·   Simulate low quality audio equipment using "Computer Music Toolkit" (CMT) plugin
           library:

                   ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12

       ·   Add reverberation to the audio using TAP-plugins (Tom's Audio Processing plugins):

                   ladspa=file=tap_reverb:tap_reverb

       ·   Generate white noise, with 0.2 amplitude:

                   ladspa=file=cmt:noise_source_white:c=c0=.2

       ·   Generate 20 bpm clicks using plugin "C* Click - Metronome" from the "C* Audio Plugin
           Suite" (CAPS) library:

                   ladspa=file=caps:Click:c=c1=20'

       ·   Apply "C* Eq10X2 - Stereo 10-band equaliser" effect:

                   ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2

       ·   Increase volume by 20dB using fast lookahead limiter from Steve Harris "SWH Plugins"
           collection:

                   ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2

       ·   Attenuate low frequencies using Multiband EQ from Steve Harris "SWH Plugins"
           collection:

                   ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0

       Commands

       This filter supports the following commands:

       cN  Modify the N-th control value.

           If the specified value is not valid, it is ignored and prior one is kept.

   loudnorm
       EBU R128 loudness normalization. Includes both dynamic and linear normalization modes.
       Support for both single pass (livestreams, files) and double pass (files) modes.  This
       algorithm can target IL, LRA, and maximum true peak.

       The filter accepts the following options:

       I, i
           Set integrated loudness target.  Range is -70.0 - -5.0. Default value is -24.0.

       LRA, lra
           Set loudness range target.  Range is 1.0 - 20.0. Default value is 7.0.

       TP, tp
           Set maximum true peak.  Range is -9.0 - +0.0. Default value is -2.0.

       measured_I, measured_i
           Measured IL of input file.  Range is -99.0 - +0.0.

       measured_LRA, measured_lra
           Measured LRA of input file.  Range is  0.0 - 99.0.

       measured_TP, measured_tp
           Measured true peak of input file.  Range is  -99.0 - +99.0.

       measured_thresh
           Measured threshold of input file.  Range is -99.0 - +0.0.

       offset
           Set offset gain. Gain is applied before the true-peak limiter.  Range is  -99.0 -
           +99.0. Default is +0.0.

       linear
           Normalize linearly if possible.  measured_I, measured_LRA, measured_TP, and
           measured_thresh must also to be specified in order to use this mode.  Options are true
           or false. Default is true.

       dual_mono
           Treat mono input files as "dual-mono". If a mono file is intended for playback on a
           stereo system, its EBU R128 measurement will be perceptually incorrect.  If set to
           "true", this option will compensate for this effect.  Multi-channel input files are
           not affected by this option.  Options are true or false. Default is false.

       print_format
           Set print format for stats. Options are summary, json, or none.  Default value is
           none.

   lowpass
       Apply a low-pass filter with 3dB point frequency.  The filter can be either single-pole or
       double-pole (the default).  The filter roll off at 6dB per pole per octave (20dB per pole
       per decade).

       The filter accepts the following options:

       frequency, f
           Set frequency in Hz. Default is 500.

       poles, p
           Set number of poles. Default is 2.

       width_type
           Set method to specify band-width of filter.

           h   Hz

           q   Q-Factor

           o   octave

           s   slope

       width, w
           Specify the band-width of a filter in width_type units.  Applies only to double-pole
           filter.  The default is 0.707q and gives a Butterworth response.

   pan
       Mix channels with specific gain levels. The filter accepts the output channel layout
       followed by a set of channels definitions.

       This filter is also designed to efficiently remap the channels of an audio stream.

       The filter accepts parameters of the form: "l|outdef|outdef|..."

       l   output channel layout or number of channels

       outdef
           output channel specification, of the form:
           "out_name=[gain*]in_name[(+-)[gain*]in_name...]"

       out_name
           output channel to define, either a channel name (FL, FR, etc.) or a channel number
           (c0, c1, etc.)

       gain
           multiplicative coefficient for the channel, 1 leaving the volume unchanged

       in_name
           input channel to use, see out_name for details; it is not possible to mix named and
           numbered input channels

       If the `=' in a channel specification is replaced by `<', then the gains for that
       specification will be renormalized so that the total is 1, thus avoiding clipping noise.

       Mixing examples

       For example, if you want to down-mix from stereo to mono, but with a bigger factor for the
       left channel:

               pan=1c|c0=0.9*c0+0.1*c1

       A customized down-mix to stereo that works automatically for 3-, 4-, 5- and 7-channels
       surround:

               pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR

       Note that ffmpeg integrates a default down-mix (and up-mix) system that should be
       preferred (see "-ac" option) unless you have very specific needs.

       Remapping examples

       The channel remapping will be effective if, and only if:

       *<gain coefficients are zeroes or ones,>
       *<only one input per channel output,>

       If all these conditions are satisfied, the filter will notify the user ("Pure channel
       mapping detected"), and use an optimized and lossless method to do the remapping.

       For example, if you have a 5.1 source and want a stereo audio stream by dropping the extra
       channels:

               pan="stereo| c0=FL | c1=FR"

       Given the same source, you can also switch front left and front right channels and keep
       the input channel layout:

               pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"

       If the input is a stereo audio stream, you can mute the front left channel (and still keep
       the stereo channel layout) with:

               pan="stereo|c1=c1"

       Still with a stereo audio stream input, you can copy the right channel in both front left
       and right:

               pan="stereo| c0=FR | c1=FR"

   replaygain
       ReplayGain scanner filter. This filter takes an audio stream as an input and outputs it
       unchanged.  At end of filtering it displays "track_gain" and "track_peak".

   resample
       Convert the audio sample format, sample rate and channel layout. It is not meant to be
       used directly.

   rubberband
       Apply time-stretching and pitch-shifting with librubberband.

       The filter accepts the following options:

       tempo
           Set tempo scale factor.

       pitch
           Set pitch scale factor.

       transients
           Set transients detector.  Possible values are:

           crisp
           mixed
           smooth
       detector
           Set detector.  Possible values are:

           compound
           percussive
           soft
       phase
           Set phase.  Possible values are:

           laminar
           independent
       window
           Set processing window size.  Possible values are:

           standard
           short
           long
       smoothing
           Set smoothing.  Possible values are:

           off
           on
       formant
           Enable formant preservation when shift pitching.  Possible values are:

           shifted
           preserved
       pitchq
           Set pitch quality.  Possible values are:

           quality
           speed
           consistency
       channels
           Set channels.  Possible values are:

           apart
           together

   sidechaincompress
       This filter acts like normal compressor but has the ability to compress detected signal
       using second input signal.  It needs two input streams and returns one output stream.
       First input stream will be processed depending on second stream signal.  The filtered
       signal then can be filtered with other filters in later stages of processing. See pan and
       amerge filter.

       The filter accepts the following options:

       level_in
           Set input gain. Default is 1. Range is between 0.015625 and 64.

       threshold
           If a signal of second stream raises above this level it will affect the gain reduction
           of first stream.  By default is 0.125. Range is between 0.00097563 and 1.

       ratio
           Set a ratio about which the signal is reduced. 1:2 means that if the level raised 4dB
           above the threshold, it will be only 2dB above after the reduction.  Default is 2.
           Range is between 1 and 20.

       attack
           Amount of milliseconds the signal has to rise above the threshold before gain
           reduction starts. Default is 20. Range is between 0.01 and 2000.

       release
           Amount of milliseconds the signal has to fall below the threshold before reduction is
           decreased again. Default is 250. Range is between 0.01 and 9000.

       makeup
           Set the amount by how much signal will be amplified after processing.  Default is 2.
           Range is from 1 and 64.

       knee
           Curve the sharp knee around the threshold to enter gain reduction more softly.
           Default is 2.82843. Range is between 1 and 8.

       link
           Choose if the "average" level between all channels of side-chain stream or the
           louder("maximum") channel of side-chain stream affects the reduction. Default is
           "average".

       detection
           Should the exact signal be taken in case of "peak" or an RMS one in case of "rms".
           Default is "rms" which is mainly smoother.

       level_sc
           Set sidechain gain. Default is 1. Range is between 0.015625 and 64.

       mix How much to use compressed signal in output. Default is 1.  Range is between 0 and 1.

       Examples

       ·   Full ffmpeg example taking 2 audio inputs, 1st input to be compressed depending on the
           signal of 2nd input and later compressed signal to be merged with 2nd input:

                   ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"

   sidechaingate
       A sidechain gate acts like a normal (wideband) gate but has the ability to filter the
       detected signal before sending it to the gain reduction stage.  Normally a gate uses the
       full range signal to detect a level above the threshold.  For example: If you cut all
       lower frequencies from your sidechain signal the gate will decrease the volume of your
       track only if not enough highs appear. With this technique you are able to reduce the
       resonation of a natural drum or remove "rumbling" of muted strokes from a heavily
       distorted guitar.  It needs two input streams and returns one output stream.  First input
       stream will be processed depending on second stream signal.

       The filter accepts the following options:

       level_in
           Set input level before filtering.  Default is 1. Allowed range is from 0.015625 to 64.

       range
           Set the level of gain reduction when the signal is below the threshold.  Default is
           0.06125. Allowed range is from 0 to 1.

       threshold
           If a signal rises above this level the gain reduction is released.  Default is 0.125.
           Allowed range is from 0 to 1.

       ratio
           Set a ratio about which the signal is reduced.  Default is 2. Allowed range is from 1
           to 9000.

       attack
           Amount of milliseconds the signal has to rise above the threshold before gain
           reduction stops.  Default is 20 milliseconds. Allowed range is from 0.01 to 9000.

       release
           Amount of milliseconds the signal has to fall below the threshold before the reduction
           is increased again. Default is 250 milliseconds.  Allowed range is from 0.01 to 9000.

       makeup
           Set amount of amplification of signal after processing.  Default is 1. Allowed range
           is from 1 to 64.

       knee
           Curve the sharp knee around the threshold to enter gain reduction more softly.
           Default is 2.828427125. Allowed range is from 1 to 8.

       detection
           Choose if exact signal should be taken for detection or an RMS like one.  Default is
           rms. Can be peak or rms.

       link
           Choose if the average level between all channels or the louder channel affects the
           reduction.  Default is average. Can be average or maximum.

       level_sc
           Set sidechain gain. Default is 1. Range is from 0.015625 to 64.

   silencedetect
       Detect silence in an audio stream.

       This filter logs a message when it detects that the input audio volume is less or equal to
       a noise tolerance value for a duration greater or equal to the minimum detected noise
       duration.

       The printed times and duration are expressed in seconds.

       The filter accepts the following options:

       duration, d
           Set silence duration until notification (default is 2 seconds).

       noise, n
           Set noise tolerance. Can be specified in dB (in case "dB" is appended to the specified
           value) or amplitude ratio. Default is -60dB, or 0.001.

       Examples

       ·   Detect 5 seconds of silence with -50dB noise tolerance:

                   silencedetect=n=-50dB:d=5

       ·   Complete example with ffmpeg to detect silence with 0.0001 noise tolerance in
           silence.mp3:

                   ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -

   silenceremove
       Remove silence from the beginning, middle or end of the audio.

       The filter accepts the following options:

       start_periods
           This value is used to indicate if audio should be trimmed at beginning of the audio. A
           value of zero indicates no silence should be trimmed from the beginning. When
           specifying a non-zero value, it trims audio up until it finds non-silence. Normally,
           when trimming silence from beginning of audio the start_periods will be 1 but it can
           be increased to higher values to trim all audio up to specific count of non-silence
           periods.  Default value is 0.

       start_duration
           Specify the amount of time that non-silence must be detected before it stops trimming
           audio. By increasing the duration, bursts of noises can be treated as silence and
           trimmed off. Default value is 0.

       start_threshold
           This indicates what sample value should be treated as silence. For digital audio, a
           value of 0 may be fine but for audio recorded from analog, you may wish to increase
           the value to account for background noise.  Can be specified in dB (in case "dB" is
           appended to the specified value) or amplitude ratio. Default value is 0.

       stop_periods
           Set the count for trimming silence from the end of audio.  To remove silence from the
           middle of a file, specify a stop_periods that is negative. This value is then treated
           as a positive value and is used to indicate the effect should restart processing as
           specified by start_periods, making it suitable for removing periods of silence in the
           middle of the audio.  Default value is 0.

       stop_duration
           Specify a duration of silence that must exist before audio is not copied any more. By
           specifying a higher duration, silence that is wanted can be left in the audio.
           Default value is 0.

       stop_threshold
           This is the same as start_threshold but for trimming silence from the end of audio.
           Can be specified in dB (in case "dB" is appended to the specified value) or amplitude
           ratio. Default value is 0.

       leave_silence
           This indicates that stop_duration length of audio should be left intact at the
           beginning of each period of silence.  For example, if you want to remove long pauses
           between words but do not want to remove the pauses completely. Default value is 0.

       detection
           Set how is silence detected. Can be "rms" or "peak". Second is faster and works better
           with digital silence which is exactly 0.  Default value is "rms".

       window
           Set ratio used to calculate size of window for detecting silence.  Default value is
           0.02. Allowed range is from 0 to 10.

       Examples

       ·   The following example shows how this filter can be used to start a recording that does
           not contain the delay at the start which usually occurs between pressing the record
           button and the start of the performance:

                   silenceremove=1:5:0.02

       ·   Trim all silence encountered from beginning to end where there is more than 1 second
           of silence in audio:

                   silenceremove=0:0:0:-1:1:-90dB

   sofalizer
       SOFAlizer uses head-related transfer functions (HRTFs) to create virtual loudspeakers
       around the user for binaural listening via headphones (audio formats up to 9 channels
       supported).  The HRTFs are stored in SOFA files (see <http://www.sofacoustics.org/> for a
       database).  SOFAlizer is developed at the Acoustics Research Institute (ARI) of the
       Austrian Academy of Sciences.

       To enable compilation of this filter you need to configure FFmpeg with "--enable-netcdf".

       The filter accepts the following options:

       sofa
           Set the SOFA file used for rendering.

       gain
           Set gain applied to audio. Value is in dB. Default is 0.

       rotation
           Set rotation of virtual loudspeakers in deg. Default is 0.

       elevation
           Set elevation of virtual speakers in deg. Default is 0.

       radius
           Set distance in meters between loudspeakers and the listener with near-field HRTFs.
           Default is 1.

       type
           Set processing type. Can be time or freq. time is processing audio in time domain
           which is slow.  freq is processing audio in frequency domain which is fast.  Default
           is freq.

       speakers
           Set custom positions of virtual loudspeakers. Syntax for this option is: <CH> <AZIM>
           <ELEV>[|<CH> <AZIM> <ELEV>|...].  Each virtual loudspeaker is described with short
           channel name following with azimuth and elevation in degreees.  Each virtual
           loudspeaker description is separated by '|'.  For example to override front left and
           front right channel positions use: 'speakers=FL 45 15|FR 345 15'.  Descriptions with
           unrecognised channel names are ignored.

       Examples

       ·   Using ClubFritz6 sofa file:

                   sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=1

       ·   Using ClubFritz12 sofa file and bigger radius with small rotation:

                   sofalizer=sofa=/path/to/ClubFritz12.sofa:type=freq:radius=2:rotation=5

       ·   Similar as above but with custom speaker positions for front left, front right, back
           left and back right and also with custom gain:

                   "sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=2:speakers=FL 45|FR 315|BL 135|BR 225:gain=28"

   stereotools
       This filter has some handy utilities to manage stereo signals, for converting M/S stereo
       recordings to L/R signal while having control over the parameters or spreading the stereo
       image of master track.

       The filter accepts the following options:

       level_in
           Set input level before filtering for both channels. Defaults is 1.  Allowed range is
           from 0.015625 to 64.

       level_out
           Set output level after filtering for both channels. Defaults is 1.  Allowed range is
           from 0.015625 to 64.

       balance_in
           Set input balance between both channels. Default is 0.  Allowed range is from -1 to 1.

       balance_out
           Set output balance between both channels. Default is 0.  Allowed range is from -1 to
           1.

       softclip
           Enable softclipping. Results in analog distortion instead of harsh digital 0dB
           clipping. Disabled by default.

       mutel
           Mute the left channel. Disabled by default.

       muter
           Mute the right channel. Disabled by default.

       phasel
           Change the phase of the left channel. Disabled by default.

       phaser
           Change the phase of the right channel. Disabled by default.

       mode
           Set stereo mode. Available values are:

           lr>lr
               Left/Right to Left/Right, this is default.

           lr>ms
               Left/Right to Mid/Side.

           ms>lr
               Mid/Side to Left/Right.

           lr>ll
               Left/Right to Left/Left.

           lr>rr
               Left/Right to Right/Right.

           lr>l+r
               Left/Right to Left + Right.

           lr>rl
               Left/Right to Right/Left.

       slev
           Set level of side signal. Default is 1.  Allowed range is from 0.015625 to 64.

       sbal
           Set balance of side signal. Default is 0.  Allowed range is from -1 to 1.

       mlev
           Set level of the middle signal. Default is 1.  Allowed range is from 0.015625 to 64.

       mpan
           Set middle signal pan. Default is 0. Allowed range is from -1 to 1.

       base
           Set stereo base between mono and inversed channels. Default is 0.  Allowed range is
           from -1 to 1.

       delay
           Set delay in milliseconds how much to delay left from right channel and vice versa.
           Default is 0. Allowed range is from -20 to 20.

       sclevel
           Set S/C level. Default is 1. Allowed range is from 1 to 100.

       phase
           Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.

       Examples

       ·   Apply karaoke like effect:

                   stereotools=mlev=0.015625

       ·   Convert M/S signal to L/R:

                   "stereotools=mode=ms>lr"

   stereowiden
       This filter enhance the stereo effect by suppressing signal common to both channels and by
       delaying the signal of left into right and vice versa, thereby widening the stereo effect.

       The filter accepts the following options:

       delay
           Time in milliseconds of the delay of left signal into right and vice versa.  Default
           is 20 milliseconds.

       feedback
           Amount of gain in delayed signal into right and vice versa. Gives a delay effect of
           left signal in right output and vice versa which gives widening effect. Default is
           0.3.

       crossfeed
           Cross feed of left into right with inverted phase. This helps in suppressing the mono.
           If the value is 1 it will cancel all the signal common to both channels. Default is
           0.3.

       drymix
           Set level of input signal of original channel. Default is 0.8.

   treble
       Boost or cut treble (upper) frequencies of the audio using a two-pole shelving filter with
       a response similar to that of a standard hi-fi's tone-controls. This is also known as
       shelving equalisation (EQ).

       The filter accepts the following options:

       gain, g
           Give the gain at whichever is the lower of ~22 kHz and the Nyquist frequency. Its
           useful range is about -20 (for a large cut) to +20 (for a large boost). Beware of
           clipping when using a positive gain.

       frequency, f
           Set the filter's central frequency and so can be used to extend or reduce the
           frequency range to be boosted or cut.  The default value is 3000 Hz.

       width_type
           Set method to specify band-width of filter.

           h   Hz

           q   Q-Factor

           o   octave

           s   slope

       width, w
           Determine how steep is the filter's shelf transition.

   tremolo
       Sinusoidal amplitude modulation.

       The filter accepts the following options:

       f   Modulation frequency in Hertz. Modulation frequencies in the subharmonic range (20 Hz
           or lower) will result in a tremolo effect.  This filter may also be used as a ring
           modulator by specifying a modulation frequency higher than 20 Hz.  Range is 0.1 -
           20000.0. Default value is 5.0 Hz.

       d   Depth of modulation as a percentage. Range is 0.0 - 1.0.  Default value is 0.5.

   vibrato
       Sinusoidal phase modulation.

       The filter accepts the following options:

       f   Modulation frequency in Hertz.  Range is 0.1 - 20000.0. Default value is 5.0 Hz.

       d   Depth of modulation as a percentage. Range is 0.0 - 1.0.  Default value is 0.5.

   volume
       Adjust the input audio volume.

       It accepts the following parameters:

       volume
           Set audio volume expression.

           Output values are clipped to the maximum value.

           The output audio volume is given by the relation:

                   <output_volume> = <volume> * <input_volume>

           The default value for volume is "1.0".

       precision
           This parameter represents the mathematical precision.

           It determines which input sample formats will be allowed, which affects the precision
           of the volume scaling.

           fixed
               8-bit fixed-point; this limits input sample format to U8, S16, and S32.

           float
               32-bit floating-point; this limits input sample format to FLT. (default)

           double
               64-bit floating-point; this limits input sample format to DBL.

       replaygain
           Choose the behaviour on encountering ReplayGain side data in input frames.

           drop
               Remove ReplayGain side data, ignoring its contents (the default).

           ignore
               Ignore ReplayGain side data, but leave it in the frame.

           track
               Prefer the track gain, if present.

           album
               Prefer the album gain, if present.

       replaygain_preamp
           Pre-amplification gain in dB to apply to the selected replaygain gain.

           Default value for replaygain_preamp is 0.0.

       eval
           Set when the volume expression is evaluated.

           It accepts the following values:

           once
               only evaluate expression once during the filter initialization, or when the volume
               command is sent

           frame
               evaluate expression for each incoming frame

           Default value is once.

       The volume expression can contain the following parameters.

       n   frame number (starting at zero)

       nb_channels
           number of channels

       nb_consumed_samples
           number of samples consumed by the filter

       nb_samples
           number of samples in the current frame

       pos original frame position in the file

       pts frame PTS

       sample_rate
           sample rate

       startpts
           PTS at start of stream

       startt
           time at start of stream

       t   frame time

       tb  timestamp timebase

       volume
           last set volume value

       Note that when eval is set to once only the sample_rate and tb variables are available,
       all other variables will evaluate to NAN.

       Commands

       This filter supports the following commands:

       volume
           Modify the volume expression.  The command accepts the same syntax of the
           corresponding option.

           If the specified expression is not valid, it is kept at its current value.

       replaygain_noclip
           Prevent clipping by limiting the gain applied.

           Default value for replaygain_noclip is 1.

       Examples

       ·   Halve the input audio volume:

                   volume=volume=0.5
                   volume=volume=1/2
                   volume=volume=-6.0206dB

           In all the above example the named key for volume can be omitted, for example like in:

                   volume=0.5

       ·   Increase input audio power by 6 decibels using fixed-point precision:

                   volume=volume=6dB:precision=fixed

       ·   Fade volume after time 10 with an annihilation period of 5 seconds:

                   volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame

   volumedetect
       Detect the volume of the input video.

       The filter has no parameters. The input is not modified. Statistics about the volume will
       be printed in the log when the input stream end is reached.

       In particular it will show the mean volume (root mean square), maximum volume (on a per-
       sample basis), and the beginning of a histogram of the registered volume values (from the
       maximum value to a cumulated 1/1000 of the samples).

       All volumes are in decibels relative to the maximum PCM value.

       Examples

       Here is an excerpt of the output:

               [Parsed_volumedetect_0  0xa23120] mean_volume: -27 dB
               [Parsed_volumedetect_0  0xa23120] max_volume: -4 dB
               [Parsed_volumedetect_0  0xa23120] histogram_4db: 6
               [Parsed_volumedetect_0  0xa23120] histogram_5db: 62
               [Parsed_volumedetect_0  0xa23120] histogram_6db: 286
               [Parsed_volumedetect_0  0xa23120] histogram_7db: 1042
               [Parsed_volumedetect_0  0xa23120] histogram_8db: 2551
               [Parsed_volumedetect_0  0xa23120] histogram_9db: 4609
               [Parsed_volumedetect_0  0xa23120] histogram_10db: 8409

       It means that:

       ·   The mean square energy is approximately -27 dB, or 10^-2.7.

       ·   The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.

       ·   There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.

       In other words, raising the volume by +4 dB does not cause any clipping, raising it by +5
       dB causes clipping for 6 samples, etc.

AUDIO SOURCES

       Below is a description of the currently available audio sources.

   abuffer
       Buffer audio frames, and make them available to the filter chain.

       This source is mainly intended for a programmatic use, in particular through the interface
       defined in libavfilter/asrc_abuffer.h.

       It accepts the following parameters:

       time_base
           The timebase which will be used for timestamps of submitted frames. It must be either
           a floating-point number or in numerator/denominator form.

       sample_rate
           The sample rate of the incoming audio buffers.

       sample_fmt
           The sample format of the incoming audio buffers.  Either a sample format name or its
           corresponding integer representation from the enum AVSampleFormat in
           libavutil/samplefmt.h

       channel_layout
           The channel layout of the incoming audio buffers.  Either a channel layout name from
           channel_layout_map in libavutil/channel_layout.c or its corresponding integer
           representation from the AV_CH_LAYOUT_* macros in libavutil/channel_layout.h

       channels
           The number of channels of the incoming audio buffers.  If both channels and
           channel_layout are specified, then they must be consistent.

       Examples

               abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo

       will instruct the source to accept planar 16bit signed stereo at 44100Hz.  Since the
       sample format with name "s16p" corresponds to the number 6 and the "stereo" channel layout
       corresponds to the value 0x3, this is equivalent to:

               abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3

   aevalsrc
       Generate an audio signal specified by an expression.

       This source accepts in input one or more expressions (one for each channel), which are
       evaluated and used to generate a corresponding audio signal.

       This source accepts the following options:

       exprs
           Set the '|'-separated expressions list for each separate channel. In case the
           channel_layout option is not specified, the selected channel layout depends on the
           number of provided expressions. Otherwise the last specified expression is applied to
           the remaining output channels.

       channel_layout, c
           Set the channel layout. The number of channels in the specified layout must be equal
           to the number of specified expressions.

       duration, d
           Set the minimum duration of the sourced audio. See the Time duration section in the
           ffmpeg-utils(1) manual for the accepted syntax.  Note that the resulting duration may
           be greater than the specified duration, as the generated audio is always cut at the
           end of a complete frame.

           If not specified, or the expressed duration is negative, the audio is supposed to be
           generated forever.

       nb_samples, n
           Set the number of samples per channel per each output frame, default to 1024.

       sample_rate, s
           Specify the sample rate, default to 44100.

       Each expression in exprs can contain the following constants:

       n   number of the evaluated sample, starting from 0

       t   time of the evaluated sample expressed in seconds, starting from 0

       s   sample rate

       Examples

       ·   Generate silence:

                   aevalsrc=0

       ·   Generate a sin signal with frequency of 440 Hz, set sample rate to 8000 Hz:

                   aevalsrc="sin(440*2*PI*t):s=8000"

       ·   Generate a two channels signal, specify the channel layout (Front Center + Back
           Center) explicitly:

                   aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"

       ·   Generate white noise:

                   aevalsrc="-2+random(0)"

       ·   Generate an amplitude modulated signal:

                   aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"

       ·   Generate 2.5 Hz binaural beats on a 360 Hz carrier:

                   aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"

   anullsrc
       The null audio source, return unprocessed audio frames. It is mainly useful as a template
       and to be employed in analysis / debugging tools, or as the source for filters which
       ignore the input data (for example the sox synth filter).

       This source accepts the following options:

       channel_layout, cl
           Specifies the channel layout, and can be either an integer or a string representing a
           channel layout. The default value of channel_layout is "stereo".

           Check the channel_layout_map definition in libavutil/channel_layout.c for the mapping
           between strings and channel layout values.

       sample_rate, r
           Specifies the sample rate, and defaults to 44100.

       nb_samples, n
           Set the number of samples per requested frames.

       Examples

       ·   Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.

                   anullsrc=r=48000:cl=4

       ·   Do the same operation with a more obvious syntax:

                   anullsrc=r=48000:cl=mono

       All the parameters need to be explicitly defined.

   flite
       Synthesize a voice utterance using the libflite library.

       To enable compilation of this filter you need to configure FFmpeg with
       "--enable-libflite".

       Note that the flite library is not thread-safe.

       The filter accepts the following options:

       list_voices
           If set to 1, list the names of the available voices and exit immediately. Default
           value is 0.

       nb_samples, n
           Set the maximum number of samples per frame. Default value is 512.

       textfile
           Set the filename containing the text to speak.

       text
           Set the text to speak.

       voice, v
           Set the voice to use for the speech synthesis. Default value is "kal". See also the
           list_voices option.

       Examples

       ·   Read from file speech.txt, and synthesize the text using the standard flite voice:

                   flite=textfile=speech.txt

       ·   Read the specified text selecting the "slt" voice:

                   flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt

       ·   Input text to ffmpeg:

                   ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt

       ·   Make ffplay speak the specified text, using "flite" and the "lavfi" device:

                   ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'

       For more information about libflite, check: <http://www.speech.cs.cmu.edu/flite/>

   anoisesrc
       Generate a noise audio signal.

       The filter accepts the following options:

       sample_rate, r
           Specify the sample rate. Default value is 48000 Hz.

       amplitude, a
           Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value is 1.0.

       duration, d
           Specify the duration of the generated audio stream. Not specifying this option results
           in noise with an infinite length.

       color, colour, c
           Specify the color of noise. Available noise colors are white, pink, and brown.
           Default color is white.

       seed, s
           Specify a value used to seed the PRNG.

       nb_samples, n
           Set the number of samples per each output frame, default is 1024.

       Examples

       ·   Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of
           0.5:

                   anoisesrc=d=60:c=pink:r=44100:a=0.5

   sine
       Generate an audio signal made of a sine wave with amplitude 1/8.

       The audio signal is bit-exact.

       The filter accepts the following options:

       frequency, f
           Set the carrier frequency. Default is 440 Hz.

       beep_factor, b
           Enable a periodic beep every second with frequency beep_factor times the carrier
           frequency. Default is 0, meaning the beep is disabled.

       sample_rate, r
           Specify the sample rate, default is 44100.

       duration, d
           Specify the duration of the generated audio stream.

       samples_per_frame
           Set the number of samples per output frame.

           The expression can contain the following constants:

           n   The (sequential) number of the output audio frame, starting from 0.

           pts The PTS (Presentation TimeStamp) of the output audio frame, expressed in TB units.

           t   The PTS of the output audio frame, expressed in seconds.

           TB  The timebase of the output audio frames.

           Default is 1024.

       Examples

       ·   Generate a simple 440 Hz sine wave:

                   sine

       ·   Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:

                   sine=220:4:d=5
                   sine=f=220:b=4:d=5
                   sine=frequency=220:beep_factor=4:duration=5

       ·   Generate a 1 kHz sine wave following "1602,1601,1602,1601,1602" NTSC pattern:

                   sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'

AUDIO SINKS

       Below is a description of the currently available audio sinks.

   abuffersink
       Buffer audio frames, and make them available to the end of filter chain.

       This sink is mainly intended for programmatic use, in particular through the interface
       defined in libavfilter/buffersink.h or the options system.

       It accepts a pointer to an AVABufferSinkContext structure, which defines the incoming
       buffers' formats, to be passed as the opaque parameter to "avfilter_init_filter" for
       initialization.

   anullsink
       Null audio sink; do absolutely nothing with the input audio. It is mainly useful as a
       template and for use in analysis / debugging tools.

VIDEO FILTERS

       When you configure your FFmpeg build, you can disable any of the existing filters using
       "--disable-filters".  The configure output will show the video filters included in your
       build.

       Below is a description of the currently available video filters.

   alphaextract
       Extract the alpha component from the input as a grayscale video. This is especially useful
       with the alphamerge filter.

   alphamerge
       Add or replace the alpha component of the primary input with the grayscale value of a
       second input. This is intended for use with alphaextract to allow the transmission or
       storage of frame sequences that have alpha in a format that doesn't support an alpha
       channel.

       For example, to reconstruct full frames from a normal YUV-encoded video and a separate
       video created with alphaextract, you might use:

               movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]

       Since this filter is designed for reconstruction, it operates on frame sequences without
       considering timestamps, and terminates when either input reaches end of stream. This will
       cause problems if your encoding pipeline drops frames. If you're trying to apply an image
       as an overlay to a video stream, consider the overlay filter instead.

   ass
       Same as the subtitles filter, except that it doesn't require libavcodec and libavformat to
       work. On the other hand, it is limited to ASS (Advanced Substation Alpha) subtitles files.

       This filter accepts the following option in addition to the common options from the
       subtitles filter:

       shaping
           Set the shaping engine

           Available values are:

           auto
               The default libass shaping engine, which is the best available.

           simple
               Fast, font-agnostic shaper that can do only substitutions

           complex
               Slower shaper using OpenType for substitutions and positioning

           The default is "auto".

   atadenoise
       Apply an Adaptive Temporal Averaging Denoiser to the video input.

       The filter accepts the following options:

       0a  Set threshold A for 1st plane. Default is 0.02.  Valid range is 0 to 0.3.

       0b  Set threshold B for 1st plane. Default is 0.04.  Valid range is 0 to 5.

       1a  Set threshold A for 2nd plane. Default is 0.02.  Valid range is 0 to 0.3.

       1b  Set threshold B for 2nd plane. Default is 0.04.  Valid range is 0 to 5.

       2a  Set threshold A for 3rd plane. Default is 0.02.  Valid range is 0 to 0.3.

       2b  Set threshold B for 3rd plane. Default is 0.04.  Valid range is 0 to 5.

           Threshold A is designed to react on abrupt changes in the input signal and threshold B
           is designed to react on continuous changes in the input signal.

       s   Set number of frames filter will use for averaging. Default is 33. Must be odd number
           in range [5, 129].

       p   Set what planes of frame filter will use for averaging. Default is all.

   avgblur
       Apply average blur filter.

       The filter accepts the following options:

       sizeX
           Set horizontal kernel size.

       planes
           Set which planes to filter. By default all planes are filtered.

       sizeY
           Set vertical kernel size, if zero it will be same as "sizeX".  Default is 0.

   bbox
       Compute the bounding box for the non-black pixels in the input frame luminance plane.

       This filter computes the bounding box containing all the pixels with a luminance value
       greater than the minimum allowed value.  The parameters describing the bounding box are
       printed on the filter log.

       The filter accepts the following option:

       min_val
           Set the minimal luminance value. Default is 16.

   bitplanenoise
       Show and measure bit plane noise.

       The filter accepts the following options:

       bitplane
           Set which plane to analyze. Default is 1.

       filter
           Filter out noisy pixels from "bitplane" set above.  Default is disabled.

   blackdetect
       Detect video intervals that are (almost) completely black. Can be useful to detect chapter
       transitions, commercials, or invalid recordings. Output lines contains the time for the
       start, end and duration of the detected black interval expressed in seconds.

       In order to display the output lines, you need to set the loglevel at least to the
       AV_LOG_INFO value.

       The filter accepts the following options:

       black_min_duration, d
           Set the minimum detected black duration expressed in seconds. It must be a non-
           negative floating point number.

           Default value is 2.0.

       picture_black_ratio_th, pic_th
           Set the threshold for considering a picture "black".  Express the minimum value for
           the ratio:

                   <nb_black_pixels> / <nb_pixels>

           for which a picture is considered black.  Default value is 0.98.

       pixel_black_th, pix_th
           Set the threshold for considering a pixel "black".

           The threshold expresses the maximum pixel luminance value for which a pixel is
           considered "black". The provided value is scaled according to the following equation:

                   <absolute_threshold> = <luminance_minimum_value> + <pixel_black_th> * <luminance_range_size>

           luminance_range_size and luminance_minimum_value depend on the input video format, the
           range is [0-255] for YUV full-range formats and [16-235] for YUV non full-range
           formats.

           Default value is 0.10.

       The following example sets the maximum pixel threshold to the minimum value, and detects
       only black intervals of 2 or more seconds:

               blackdetect=d=2:pix_th=0.00

   blackframe
       Detect frames that are (almost) completely black. Can be useful to detect chapter
       transitions or commercials. Output lines consist of the frame number of the detected
       frame, the percentage of blackness, the position in the file if known or -1 and the
       timestamp in seconds.

       In order to display the output lines, you need to set the loglevel at least to the
       AV_LOG_INFO value.

       This filter exports frame metadata "lavfi.blackframe.pblack".  The value represents the
       percentage of pixels in the picture that are below the threshold value.

       It accepts the following parameters:

       amount
           The percentage of the pixels that have to be below the threshold; it defaults to 98.

       threshold, thresh
           The threshold below which a pixel value is considered black; it defaults to 32.

   blend, tblend
       Blend two video frames into each other.

       The "blend" filter takes two input streams and outputs one stream, the first input is the
       "top" layer and second input is "bottom" layer.  By default, the output terminates when
       the longest input terminates.

       The "tblend" (time blend) filter takes two consecutive frames from one single stream, and
       outputs the result obtained by blending the new frame on top of the old frame.

       A description of the accepted options follows.

       c0_mode
       c1_mode
       c2_mode
       c3_mode
       all_mode
           Set blend mode for specific pixel component or all pixel components in case of
           all_mode. Default value is "normal".

           Available values for component modes are:

           addition
           addition128
           and
           average
           burn
           darken
           difference
           difference128
           divide
           dodge
           freeze
           exclusion
           glow
           hardlight
           hardmix
           heat
           lighten
           linearlight
           multiply
           multiply128
           negation
           normal
           or
           overlay
           phoenix
           pinlight
           reflect
           screen
           softlight
           subtract
           vividlight
           xor
       c0_opacity
       c1_opacity
       c2_opacity
       c3_opacity
       all_opacity
           Set blend opacity for specific pixel component or all pixel components in case of
           all_opacity. Only used in combination with pixel component blend modes.

       c0_expr
       c1_expr
       c2_expr
       c3_expr
       all_expr
           Set blend expression for specific pixel component or all pixel components in case of
           all_expr. Note that related mode options will be ignored if those are set.

           The expressions can use the following variables:

           N   The sequential number of the filtered frame, starting from 0.

           X
           Y   the coordinates of the current sample

           W
           H   the width and height of currently filtered plane

           SW
           SH  Width and height scale depending on the currently filtered plane. It is the ratio
               between the corresponding luma plane number of pixels and the current plane ones.
               E.g. for YUV4:2:0 the values are "1,1" for the luma plane, and "0.5,0.5" for
               chroma planes.

           T   Time of the current frame, expressed in seconds.

           TOP, A
               Value of pixel component at current location for first video frame (top layer).

           BOTTOM, B
               Value of pixel component at current location for second video frame (bottom
               layer).

       shortest
           Force termination when the shortest input terminates. Default is 0. This option is
           only defined for the "blend" filter.

       repeatlast
           Continue applying the last bottom frame after the end of the stream. A value of 0
           disable the filter after the last frame of the bottom layer is reached.  Default is 1.
           This option is only defined for the "blend" filter.

       Examples

       ·   Apply transition from bottom layer to top layer in first 10 seconds:

                   blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'

       ·   Apply 1x1 checkerboard effect:

                   blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'

       ·   Apply uncover left effect:

                   blend=all_expr='if(gte(N*SW+X,W),A,B)'

       ·   Apply uncover down effect:

                   blend=all_expr='if(gte(Y-N*SH,0),A,B)'

       ·   Apply uncover up-left effect:

                   blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'

       ·   Split diagonally video and shows top and bottom layer on each side:

                   blend=all_expr=if(gt(X,Y*(W/H)),A,B)

       ·   Display differences between the current and the previous frame:

                   tblend=all_mode=difference128

   boxblur
       Apply a boxblur algorithm to the input video.

       It accepts the following parameters:

       luma_radius, lr
       luma_power, lp
       chroma_radius, cr
       chroma_power, cp
       alpha_radius, ar
       alpha_power, ap

       A description of the accepted options follows.

       luma_radius, lr
       chroma_radius, cr
       alpha_radius, ar
           Set an expression for the box radius in pixels used for blurring the corresponding
           input plane.

           The radius value must be a non-negative number, and must not be greater than the value
           of the expression "min(w,h)/2" for the luma and alpha planes, and of "min(cw,ch)/2"
           for the chroma planes.

           Default value for luma_radius is "2". If not specified, chroma_radius and alpha_radius
           default to the corresponding value set for luma_radius.

           The expressions can contain the following constants:

           w
           h   The input width and height in pixels.

           cw
           ch  The input chroma image width and height in pixels.

           hsub
           vsub
               The horizontal and vertical chroma subsample values. For example, for the pixel
               format "yuv422p", hsub is 2 and vsub is 1.

       luma_power, lp
       chroma_power, cp
       alpha_power, ap
           Specify how many times the boxblur filter is applied to the corresponding plane.

           Default value for luma_power is 2. If not specified, chroma_power and alpha_power
           default to the corresponding value set for luma_power.

           A value of 0 will disable the effect.

       Examples

       ·   Apply a boxblur filter with the luma, chroma, and alpha radii set to 2:

                   boxblur=luma_radius=2:luma_power=1
                   boxblur=2:1

       ·   Set the luma radius to 2, and alpha and chroma radius to 0:

                   boxblur=2:1:cr=0:ar=0

       ·   Set the luma and chroma radii to a fraction of the video dimension:

                   boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1

   bwdif
       Deinterlace the input video ("bwdif" stands for "Bob Weaver Deinterlacing Filter").

       Motion adaptive deinterlacing based on yadif with the use of w3fdif and cubic
       interpolation algorithms.  It accepts the following parameters:

       mode
           The interlacing mode to adopt. It accepts one of the following values:

           0, send_frame
               Output one frame for each frame.

           1, send_field
               Output one frame for each field.

           The default value is "send_field".

       parity
           The picture field parity assumed for the input interlaced video. It accepts one of the
           following values:

           0, tff
               Assume the top field is first.

           1, bff
               Assume the bottom field is first.

           -1, auto
               Enable automatic detection of field parity.

           The default value is "auto".  If the interlacing is unknown or the decoder does not
           export this information, top field first will be assumed.

       deint
           Specify which frames to deinterlace. Accept one of the following values:

           0, all
               Deinterlace all frames.

           1, interlaced
               Only deinterlace frames marked as interlaced.

           The default value is "all".

   chromakey
       YUV colorspace color/chroma keying.

       The filter accepts the following options:

       color
           The color which will be replaced with transparency.

       similarity
           Similarity percentage with the key color.

           0.01 matches only the exact key color, while 1.0 matches everything.

       blend
           Blend percentage.

           0.0 makes pixels either fully transparent, or not transparent at all.

           Higher values result in semi-transparent pixels, with a higher transparency the more
           similar the pixels color is to the key color.

       yuv Signals that the color passed is already in YUV instead of RGB.

           Litteral colors like "green" or "red" don't make sense with this enabled anymore.
           This can be used to pass exact YUV values as hexadecimal numbers.

       Examples

       ·   Make every green pixel in the input image transparent:

                   ffmpeg -i input.png -vf chromakey=green out.png

       ·   Overlay a greenscreen-video on top of a static black background.

                   ffmpeg -f lavfi -i color=c=black:s=1280x720 -i video.mp4 -shortest -filter_complex "[1:v]chromakey=0x70de77:0.1:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.mkv

   ciescope
       Display CIE color diagram with pixels overlaid onto it.

       The filter accepts the following options:

       system
           Set color system.

           ntsc, 470m
           ebu, 470bg
           smpte
           240m
           apple
           widergb
           cie1931
           rec709, hdtv
           uhdtv, rec2020
       cie Set CIE system.

           xyy
           ucs
           luv
       gamuts
           Set what gamuts to draw.

           See "system" option for available values.

       size, s
           Set ciescope size, by default set to 512.

       intensity, i
           Set intensity used to map input pixel values to CIE diagram.

       contrast
           Set contrast used to draw tongue colors that are out of active color system gamut.

       corrgamma
           Correct gamma displayed on scope, by default enabled.

       showwhite
           Show white point on CIE diagram, by default disabled.

       gamma
           Set input gamma. Used only with XYZ input color space.

   codecview
       Visualize information exported by some codecs.

       Some codecs can export information through frames using side-data or other means. For
       example, some MPEG based codecs export motion vectors through the export_mvs flag in the
       codec flags2 option.

       The filter accepts the following option:

       mv  Set motion vectors to visualize.

           Available flags for mv are:

           pf  forward predicted MVs of P-frames

           bf  forward predicted MVs of B-frames

           bb  backward predicted MVs of B-frames

       qp  Display quantization parameters using the chroma planes.

       mv_type, mvt
           Set motion vectors type to visualize. Includes MVs from all frames unless specified by
           frame_type option.

           Available flags for mv_type are:

           fp  forward predicted MVs

           bp  backward predicted MVs

       frame_type, ft
           Set frame type to visualize motion vectors of.

           Available flags for frame_type are:

           if  intra-coded frames (I-frames)

           pf  predicted frames (P-frames)

           bf  bi-directionally predicted frames (B-frames)

       Examples

       ·   Visualize forward predicted MVs of all frames using ffplay:

                   ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv_type=fp

       ·   Visualize multi-directionals MVs of P and B-Frames using ffplay:

                   ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv=pf+bf+bb

   colorbalance
       Modify intensity of primary colors (red, green and blue) of input frames.

       The filter allows an input frame to be adjusted in the shadows, midtones or highlights
       regions for the red-cyan, green-magenta or blue-yellow balance.

       A positive adjustment value shifts the balance towards the primary color, a negative value
       towards the complementary color.

       The filter accepts the following options:

       rs
       gs
       bs  Adjust red, green and blue shadows (darkest pixels).

       rm
       gm
       bm  Adjust red, green and blue midtones (medium pixels).

       rh
       gh
       bh  Adjust red, green and blue highlights (brightest pixels).

           Allowed ranges for options are "[-1.0, 1.0]". Defaults are 0.

       Examples

       ·   Add red color cast to shadows:

                   colorbalance=rs=.3

   colorkey
       RGB colorspace color keying.

       The filter accepts the following options:

       color
           The color which will be replaced with transparency.

       similarity
           Similarity percentage with the key color.

           0.01 matches only the exact key color, while 1.0 matches everything.

       blend
           Blend percentage.

           0.0 makes pixels either fully transparent, or not transparent at all.

           Higher values result in semi-transparent pixels, with a higher transparency the more
           similar the pixels color is to the key color.

       Examples

       ·   Make every green pixel in the input image transparent:

                   ffmpeg -i input.png -vf colorkey=green out.png

       ·   Overlay a greenscreen-video on top of a static background image.

                   ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv

   colorlevels
       Adjust video input frames using levels.

       The filter accepts the following options:

       rimin
       gimin
       bimin
       aimin
           Adjust red, green, blue and alpha input black point.  Allowed ranges for options are
           "[-1.0, 1.0]". Defaults are 0.

       rimax
       gimax
       bimax
       aimax
           Adjust red, green, blue and alpha input white point.  Allowed ranges for options are
           "[-1.0, 1.0]". Defaults are 1.

           Input levels are used to lighten highlights (bright tones), darken shadows (dark
           tones), change the balance of bright and dark tones.

       romin
       gomin
       bomin
       aomin
           Adjust red, green, blue and alpha output black point.  Allowed ranges for options are
           "[0, 1.0]". Defaults are 0.

       romax
       gomax
       bomax
       aomax
           Adjust red, green, blue and alpha output white point.  Allowed ranges for options are
           "[0, 1.0]". Defaults are 1.

           Output levels allows manual selection of a constrained output level range.

       Examples

       ·   Make video output darker:

                   colorlevels=rimin=0.058:gimin=0.058:bimin=0.058

       ·   Increase contrast:

                   colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96

       ·   Make video output lighter:

                   colorlevels=rimax=0.902:gimax=0.902:bimax=0.902

       ·   Increase brightness:

                   colorlevels=romin=0.5:gomin=0.5:bomin=0.5

   colorchannelmixer
       Adjust video input frames by re-mixing color channels.

       This filter modifies a color channel by adding the values associated to the other channels
       of the same pixels. For example if the value to modify is red, the output value will be:

               <red>=<red>*<rr> + <blue>*<rb> + <green>*<rg> + <alpha>*<ra>

       The filter accepts the following options:

       rr
       rg
       rb
       ra  Adjust contribution of input red, green, blue and alpha channels for output red
           channel.  Default is 1 for rr, and 0 for rg, rb and ra.

       gr
       gg
       gb
       ga  Adjust contribution of input red, green, blue and alpha channels for output green
           channel.  Default is 1 for gg, and 0 for gr, gb and ga.

       br
       bg
       bb
       ba  Adjust contribution of input red, green, blue and alpha channels for output blue
           channel.  Default is 1 for bb, and 0 for br, bg and ba.

       ar
       ag
       ab
       aa  Adjust contribution of input red, green, blue and alpha channels for output alpha
           channel.  Default is 1 for aa, and 0 for ar, ag and ab.

           Allowed ranges for options are "[-2.0, 2.0]".

       Examples

       ·   Convert source to grayscale:

                   colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3

       ·   Simulate sepia tones:

                   colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131

   colormatrix
       Convert color matrix.

       The filter accepts the following options:

       src
       dst Specify the source and destination color matrix. Both values must be specified.

           The accepted values are:

           bt709
               BT.709

           fcc FCC

           bt601
               BT.601

           bt470
               BT.470

           bt470bg
               BT.470BG

           smpte170m
               SMPTE-170M

           smpte240m
               SMPTE-240M

           bt2020
               BT.2020

       For example to convert from BT.601 to SMPTE-240M, use the command:

               colormatrix=bt601:smpte240m

   colorspace
       Convert colorspace, transfer characteristics or color primaries.  Input video needs to
       have an even size.

       The filter accepts the following options:

       all Specify all color properties at once.

           The accepted values are:

           bt470m
               BT.470M

           bt470bg
               BT.470BG

           bt601-6-525
               BT.601-6 525

           bt601-6-625
               BT.601-6 625

           bt709
               BT.709

           smpte170m
               SMPTE-170M

           smpte240m
               SMPTE-240M

           bt2020
               BT.2020

       space
           Specify output colorspace.

           The accepted values are:

           bt709
               BT.709

           fcc FCC

           bt470bg
               BT.470BG or BT.601-6 625

           smpte170m
               SMPTE-170M or BT.601-6 525

           smpte240m
               SMPTE-240M

           ycgco
               YCgCo

           bt2020ncl
               BT.2020 with non-constant luminance

       trc Specify output transfer characteristics.

           The accepted values are:

           bt709
               BT.709

           bt470m
               BT.470M

           bt470bg
               BT.470BG

           gamma22
               Constant gamma of 2.2

           gamma28
               Constant gamma of 2.8

           smpte170m
               SMPTE-170M, BT.601-6 625 or BT.601-6 525

           smpte240m
               SMPTE-240M

           srgb
               SRGB

           iec61966-2-1
               iec61966-2-1

           iec61966-2-4
               iec61966-2-4

           xvycc
               xvycc

           bt2020-10
               BT.2020 for 10-bits content

           bt2020-12
               BT.2020 for 12-bits content

       primaries
           Specify output color primaries.

           The accepted values are:

           bt709
               BT.709

           bt470m
               BT.470M

           bt470bg
               BT.470BG or BT.601-6 625

           smpte170m
               SMPTE-170M or BT.601-6 525

           smpte240m
               SMPTE-240M

           film
               film

           smpte431
               SMPTE-431

           smpte432
               SMPTE-432

           bt2020
               BT.2020

       range
           Specify output color range.

           The accepted values are:

           tv  TV (restricted) range

           mpeg
               MPEG (restricted) range

           pc  PC (full) range

           jpeg
               JPEG (full) range

       format
           Specify output color format.

           The accepted values are:

           yuv420p
               YUV 4:2:0 planar 8-bits

           yuv420p10
               YUV 4:2:0 planar 10-bits

           yuv420p12
               YUV 4:2:0 planar 12-bits

           yuv422p
               YUV 4:2:2 planar 8-bits

           yuv422p10
               YUV 4:2:2 planar 10-bits

           yuv422p12
               YUV 4:2:2 planar 12-bits

           yuv444p
               YUV 4:4:4 planar 8-bits

           yuv444p10
               YUV 4:4:4 planar 10-bits

           yuv444p12
               YUV 4:4:4 planar 12-bits

       fast
           Do a fast conversion, which skips gamma/primary correction. This will take
           significantly less CPU, but will be mathematically incorrect. To get output compatible
           with that produced by the colormatrix filter, use fast=1.

       dither
           Specify dithering mode.

           The accepted values are:

           none
               No dithering

           fsb Floyd-Steinberg dithering

       wpadapt
           Whitepoint adaptation mode.

           The accepted values are:

           bradford
               Bradford whitepoint adaptation

           vonkries
               von Kries whitepoint adaptation

           identity
               identity whitepoint adaptation (i.e. no whitepoint adaptation)

       iall
           Override all input properties at once. Same accepted values as all.

       ispace
           Override input colorspace. Same accepted values as space.

       iprimaries
           Override input color primaries. Same accepted values as primaries.

       itrc
           Override input transfer characteristics. Same accepted values as trc.

       irange
           Override input color range. Same accepted values as range.

       The filter converts the transfer characteristics, color space and color primaries to the
       specified user values. The output value, if not specified, is set to a default value based
       on the "all" property. If that property is also not specified, the filter will log an
       error. The output color range and format default to the same value as the input color
       range and format. The input transfer characteristics, color space, color primaries and
       color range should be set on the input data. If any of these are missing, the filter will
       log an error and no conversion will take place.

       For example to convert the input to SMPTE-240M, use the command:

               colorspace=smpte240m

   convolution
       Apply convolution 3x3 or 5x5 filter.

       The filter accepts the following options:

       0m
       1m
       2m
       3m  Set matrix for each plane.  Matrix is sequence of 9 or 25 signed integers.

       0rdiv
       1rdiv
       2rdiv
       3rdiv
           Set multiplier for calculated value for each plane.

       0bias
       1bias
       2bias
       3bias
           Set bias for each plane. This value is added to the result of the multiplication.
           Useful for making the overall image brighter or darker. Default is 0.0.

       Examples

       ·   Apply sharpen:

                   convolution="0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0"

       ·   Apply blur:

                   convolution="1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1/9:1/9:1/9:1/9"

       ·   Apply edge enhance:

                   convolution="0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:5:1:1:1:0:128:128:128"

       ·   Apply edge detect:

                   convolution="0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:5:5:5:1:0:128:128:128"

       ·   Apply emboss:

                   convolution="-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2"

   copy
       Copy the input source unchanged to the output. This is mainly useful for testing purposes.

   coreimage
       Video filtering on GPU using Apple's CoreImage API on OSX.

       Hardware acceleration is based on an OpenGL context. Usually, this means it is processed
       by video hardware. However, software-based OpenGL implementations exist which means there
       is no guarantee for hardware processing. It depends on the respective OSX.

       There are many filters and image generators provided by Apple that come with a large
       variety of options. The filter has to be referenced by its name along with its options.

       The coreimage filter accepts the following options:

       list_filters
           List all available filters and generators along with all their respective options as
           well as possible minimum and maximum values along with the default values.

                   list_filters=true

       filter
           Specify all filters by their respective name and options.  Use list_filters to
           determine all valid filter names and options.  Numerical options are specified by a
           float value and are automatically clamped to their respective value range.  Vector and
           color options have to be specified by a list of space separated float values.
           Character escaping has to be done.  A special option name "default" is available to
           use default options for a filter.

           It is required to specify either "default" or at least one of the filter options.  All
           omitted options are used with their default values.  The syntax of the filter string
           is as follows:

                   filter=<NAME>@<OPTION>=<VALUE>[@<OPTION>=<VALUE>][@...][#<NAME>@<OPTION>=<VALUE>[@<OPTION>=<VALUE>][@...]][#...]

       output_rect
           Specify a rectangle where the output of the filter chain is copied into the input
           image. It is given by a list of space separated float values:

                   output_rect=x\ y\ width\ height

           If not given, the output rectangle equals the dimensions of the input image.  The
           output rectangle is automatically cropped at the borders of the input image. Negative
           values are valid for each component.

                   output_rect=25\ 25\ 100\ 100

       Several filters can be chained for successive processing without GPU-HOST transfers
       allowing for fast processing of complex filter chains.  Currently, only filters with zero
       (generators) or exactly one (filters) input image and one output image are supported.
       Also, transition filters are not yet usable as intended.

       Some filters generate output images with additional padding depending on the respective
       filter kernel. The padding is automatically removed to ensure the filter output has the
       same size as the input image.

       For image generators, the size of the output image is determined by the previous output
       image of the filter chain or the input image of the whole filterchain, respectively. The
       generators do not use the pixel information of this image to generate their output.
       However, the generated output is blended onto this image, resulting in partial or complete
       coverage of the output image.

       The coreimagesrc video source can be used for generating input images which are directly
       fed into the filter chain. By using it, providing input images by another video source or
       an input video is not required.

       Examples

       ·   List all filters available:

                   coreimage=list_filters=true

       ·   Use the CIBoxBlur filter with default options to blur an image:

                   coreimage=filter=CIBoxBlur@default

       ·   Use a filter chain with CISepiaTone at default values and CIVignetteEffect with its
           center at 100x100 and a radius of 50 pixels:

                   coreimage=filter=CIBoxBlur@default#CIVignetteEffect@inputCenter=100\ 100@inputRadius=50

       ·   Use nullsrc and CIQRCodeGenerator to create a QR code for the FFmpeg homepage, given
           as complete and escaped command-line for Apple's standard bash shell:

                   ffmpeg -f lavfi -i nullsrc=s=100x100,coreimage=filter=CIQRCodeGenerator@inputMessage=https\\\\\://FFmpeg.org/@inputCorrectionLevel=H -frames:v 1 QRCode.png

   crop
       Crop the input video to given dimensions.

       It accepts the following parameters:

       w, out_w
           The width of the output video. It defaults to "iw".  This expression is evaluated only
           once during the filter configuration, or when the w or out_w command is sent.

       h, out_h
           The height of the output video. It defaults to "ih".  This expression is evaluated
           only once during the filter configuration, or when the h or out_h command is sent.

       x   The horizontal position, in the input video, of the left edge of the output video. It
           defaults to "(in_w-out_w)/2".  This expression is evaluated per-frame.

       y   The vertical position, in the input video, of the top edge of the output video.  It
           defaults to "(in_h-out_h)/2".  This expression is evaluated per-frame.

       keep_aspect
           If set to 1 will force the output display aspect ratio to be the same of the input, by
           changing the output sample aspect ratio. It defaults to 0.

       exact
           Enable exact cropping. If enabled, subsampled videos will be cropped at exact
           width/height/x/y as specified and will not be rounded to nearest smaller value.  It
           defaults to 0.

       The out_w, out_h, x, y parameters are expressions containing the following constants:

       x
       y   The computed values for x and y. They are evaluated for each new frame.

       in_w
       in_h
           The input width and height.

       iw
       ih  These are the same as in_w and in_h.

       out_w
       out_h
           The output (cropped) width and height.

       ow
       oh  These are the same as out_w and out_h.

       a   same as iw / ih

       sar input sample aspect ratio

       dar input display aspect ratio, it is the same as (iw / ih) * sar

       hsub
       vsub
           horizontal and vertical chroma subsample values. For example for the pixel format
           "yuv422p" hsub is 2 and vsub is 1.

       n   The number of the input frame, starting from 0.

       pos the position in the file of the input frame, NAN if unknown

       t   The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.

       The expression for out_w may depend on the value of out_h, and the expression for out_h
       may depend on out_w, but they cannot depend on x and y, as x and y are evaluated after
       out_w and out_h.

       The x and y parameters specify the expressions for the position of the top-left corner of
       the output (non-cropped) area. They are evaluated for each frame. If the evaluated value
       is not valid, it is approximated to the nearest valid value.

       The expression for x may depend on y, and the expression for y may depend on x.

       Examples

       ·   Crop area with size 100x100 at position (12,34).

                   crop=100:100:12:34

           Using named options, the example above becomes:

                   crop=w=100:h=100:x=12:y=34

       ·   Crop the central input area with size 100x100:

                   crop=100:100

       ·   Crop the central input area with size 2/3 of the input video:

                   crop=2/3*in_w:2/3*in_h

       ·   Crop the input video central square:

                   crop=out_w=in_h
                   crop=in_h

       ·   Delimit the rectangle with the top-left corner placed at position 100:100 and the
           right-bottom corner corresponding to the right-bottom corner of the input image.

                   crop=in_w-100:in_h-100:100:100

       ·   Crop 10 pixels from the left and right borders, and 20 pixels from the top and bottom
           borders

                   crop=in_w-2*10:in_h-2*20

       ·   Keep only the bottom right quarter of the input image:

                   crop=in_w/2:in_h/2:in_w/2:in_h/2

       ·   Crop height for getting Greek harmony:

                   crop=in_w:1/PHI*in_w

       ·   Apply trembling effect:

                   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)

       ·   Apply erratic camera effect depending on timestamp:

                   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)"

       ·   Set x depending on the value of y:

                   crop=in_w/2:in_h/2:y:10+10*sin(n/10)

       Commands

       This filter supports the following commands:

       w, out_w
       h, out_h
       x
       y   Set width/height of the output video and the horizontal/vertical position in the input
           video.  The command accepts the same syntax of the corresponding option.

           If the specified expression is not valid, it is kept at its current value.

   cropdetect
       Auto-detect the crop size.

       It calculates the necessary cropping parameters and prints the recommended parameters via
       the logging system. The detected dimensions correspond to the non-black area of the input
       video.

       It accepts the following parameters:

       limit
           Set higher black value threshold, which can be optionally specified from nothing (0)
           to everything (255 for 8-bit based formats). An intensity value greater to the set
           value is considered non-black. It defaults to 24.  You can also specify a value
           between 0.0 and 1.0 which will be scaled depending on the bitdepth of the pixel
           format.

       round
           The value which the width/height should be divisible by. It defaults to 16. The offset
           is automatically adjusted to center the video. Use 2 to get only even dimensions
           (needed for 4:2:2 video). 16 is best when encoding to most video codecs.

       reset_count, reset
           Set the counter that determines after how many frames cropdetect will reset the
           previously detected largest video area and start over to detect the current optimal
           crop area. Default value is 0.

           This can be useful when channel logos distort the video area. 0 indicates 'never
           reset', and returns the largest area encountered during playback.

   curves
       Apply color adjustments using curves.

       This filter is similar to the Adobe Photoshop and GIMP curves tools. Each component (red,
       green and blue) has its values defined by N key points tied from each other using a smooth
       curve. The x-axis represents the pixel values from the input frame, and the y-axis the new
       pixel values to be set for the output frame.

       By default, a component curve is defined by the two points (0;0) and (1;1). This creates a
       straight line where each original pixel value is "adjusted" to its own value, which means
       no change to the image.

       The filter allows you to redefine these two points and add some more. A new curve (using a
       natural cubic spline interpolation) will be define to pass smoothly through all these new
       coordinates. The new defined points needs to be strictly increasing over the x-axis, and
       their x and y values must be in the [0;1] interval.  If the computed curves happened to go
       outside the vector spaces, the values will be clipped accordingly.

       The filter accepts the following options:

       preset
           Select one of the available color presets. This option can be used in addition to the
           r, g, b parameters; in this case, the later options takes priority on the preset
           values.  Available presets are:

           none
           color_negative
           cross_process
           darker
           increase_contrast
           lighter
           linear_contrast
           medium_contrast
           negative
           strong_contrast
           vintage

           Default is "none".

       master, m
           Set the master key points. These points will define a second pass mapping. It is
           sometimes called a "luminance" or "value" mapping. It can be used with r, g, b or all
           since it acts like a post-processing LUT.

       red, r
           Set the key points for the red component.

       green, g
           Set the key points for the green component.

       blue, b
           Set the key points for the blue component.

       all Set the key points for all components (not including master).  Can be used in addition
           to the other key points component options. In this case, the unset component(s) will
           fallback on this all setting.

       psfile
           Specify a Photoshop curves file (".acv") to import the settings from.

       plot
           Save Gnuplot script of the curves in specified file.

       To avoid some filtergraph syntax conflicts, each key points list need to be defined using
       the following syntax: "x0/y0 x1/y1 x2/y2 ...".

       Examples

       ·   Increase slightly the middle level of blue:

                   curves=blue='0/0 0.5/0.58 1/1'

       ·   Vintage effect:

                   curves=r='0/0.11 .42/.51 1/0.95':g='0/0 0.50/0.48 1/1':b='0/0.22 .49/.44 1/0.8'

           Here we obtain the following coordinates for each components:

           red "(0;0.11) (0.42;0.51) (1;0.95)"

           green
               "(0;0) (0.50;0.48) (1;1)"

           blue
               "(0;0.22) (0.49;0.44) (1;0.80)"

       ·   The previous example can also be achieved with the associated built-in preset:

                   curves=preset=vintage

       ·   Or simply:

                   curves=vintage

       ·   Use a Photoshop preset and redefine the points of the green component:

                   curves=psfile='MyCurvesPresets/purple.acv':green='0/0 0.45/0.53 1/1'

       ·   Check out the curves of the "cross_process" profile using ffmpeg and gnuplot:

                   ffmpeg -f lavfi -i color -vf curves=cross_process:plot=/tmp/curves.plt -frames:v 1 -f null -
                   gnuplot -p /tmp/curves.plt

   datascope
       Video data analysis filter.

       This filter shows hexadecimal pixel values of part of video.

       The filter accepts the following options:

       size, s
           Set output video size.

       x   Set x offset from where to pick pixels.

       y   Set y offset from where to pick pixels.

       mode
           Set scope mode, can be one of the following:

           mono
               Draw hexadecimal pixel values with white color on black background.

           color
               Draw hexadecimal pixel values with input video pixel color on black background.

           color2
               Draw hexadecimal pixel values on color background picked from input video, the
               text color is picked in such way so its always visible.

       axis
           Draw rows and columns numbers on left and top of video.

       opacity
           Set background opacity.

   dctdnoiz
       Denoise frames using 2D DCT (frequency domain filtering).

       This filter is not designed for real time.

       The filter accepts the following options:

       sigma, s
           Set the noise sigma constant.

           This sigma defines a hard threshold of "3 * sigma"; every DCT coefficient (absolute
           value) below this threshold with be dropped.

           If you need a more advanced filtering, see expr.

           Default is 0.

       overlap
           Set number overlapping pixels for each block. Since the filter can be slow, you may
           want to reduce this value, at the cost of a less effective filter and the risk of
           various artefacts.

           If the overlapping value doesn't permit processing the whole input width or height, a
           warning will be displayed and according borders won't be denoised.

           Default value is blocksize-1, which is the best possible setting.

       expr, e
           Set the coefficient factor expression.

           For each coefficient of a DCT block, this expression will be evaluated as a multiplier
           value for the coefficient.

           If this is option is set, the sigma option will be ignored.

           The absolute value of the coefficient can be accessed through the c variable.

       n   Set the blocksize using the number of bits. "1<<n" defines the blocksize, which is the
           width and height of the processed blocks.

           The default value is 3 (8x8) and can be raised to 4 for a blocksize of 16x16. Note
           that changing this setting has huge consequences on the speed processing. Also, a
           larger block size does not necessarily means a better de-noising.

       Examples

       Apply a denoise with a sigma of 4.5:

               dctdnoiz=4.5

       The same operation can be achieved using the expression system:

               dctdnoiz=e='gte(c, 4.5*3)'

       Violent denoise using a block size of "16x16":

               dctdnoiz=15:n=4

   deband
       Remove banding artifacts from input video.  It works by replacing banded pixels with
       average value of referenced pixels.

       The filter accepts the following options:

       1thr
       2thr
       3thr
       4thr
           Set banding detection threshold for each plane. Default is 0.02.  Valid range is
           0.00003 to 0.5.  If difference between current pixel and reference pixel is less than
           threshold, it will be considered as banded.

       range, r
           Banding detection range in pixels. Default is 16. If positive, random number in range
           0 to set value will be used. If negative, exact absolute value will be used.  The
           range defines square of four pixels around current pixel.

       direction, d
           Set direction in radians from which four pixel will be compared. If positive, random
           direction from 0 to set direction will be picked. If negative, exact of absolute value
           will be picked. For example direction 0, -PI or -2*PI radians will pick only pixels on
           same row and -PI/2 will pick only pixels on same column.

       blur, b
           If enabled, current pixel is compared with average value of all four surrounding
           pixels. The default is enabled. If disabled current pixel is compared with all four
           surrounding pixels. The pixel is considered banded if only all four differences with
           surrounding pixels are less than threshold.

       coupling, c
           If enabled, current pixel is changed if and only if all pixel components are banded,
           e.g. banding detection threshold is triggered for all color components.  The default
           is disabled.

   decimate
       Drop duplicated frames at regular intervals.

       The filter accepts the following options:

       cycle
           Set the number of frames from which one will be dropped. Setting this to N means one
           frame in every batch of N frames will be dropped.  Default is 5.

       dupthresh
           Set the threshold for duplicate detection. If the difference metric for a frame is
           less than or equal to this value, then it is declared as duplicate. Default is 1.1

       scthresh
           Set scene change threshold. Default is 15.

       blockx
       blocky
           Set the size of the x and y-axis blocks used during metric calculations.  Larger
           blocks give better noise suppression, but also give worse detection of small
           movements. Must be a power of two. Default is 32.

       ppsrc
           Mark main input as a pre-processed input and activate clean source input stream. This
           allows the input to be pre-processed with various filters to help the metrics
           calculation while keeping the frame selection lossless. When set to 1, the first
           stream is for the pre-processed input, and the second stream is the clean source from
           where the kept frames are chosen. Default is 0.

       chroma
           Set whether or not chroma is considered in the metric calculations. Default is 1.

   deflate
       Apply deflate effect to the video.

       This filter replaces the pixel by the local(3x3) average by taking into account only
       values lower than the pixel.

       It accepts the following options:

       threshold0
       threshold1
       threshold2
       threshold3
           Limit the maximum change for each plane, default is 65535.  If 0, plane will remain
           unchanged.

   dejudder
       Remove judder produced by partially interlaced telecined content.

       Judder can be introduced, for instance, by pullup filter. If the original source was
       partially telecined content then the output of "pullup,dejudder" will have a variable
       frame rate. May change the recorded frame rate of the container. Aside from that change,
       this filter will not affect constant frame rate video.

       The option available in this filter is:

       cycle
           Specify the length of the window over which the judder repeats.

           Accepts any integer greater than 1. Useful values are:

           4   If the original was telecined from 24 to 30 fps (Film to NTSC).

           5   If the original was telecined from 25 to 30 fps (PAL to NTSC).

           20  If a mixture of the two.

           The default is 4.

   delogo
       Suppress a TV station logo by a simple interpolation of the surrounding pixels. Just set a
       rectangle covering the logo and watch it disappear (and sometimes something even uglier
       appear - your mileage may vary).

       It accepts the following parameters:

       x
       y   Specify the top left corner coordinates of the logo. They must be specified.

       w
       h   Specify the width and height of the logo to clear. They must be specified.

       band, t
           Specify the thickness of the fuzzy edge of the rectangle (added to w and h). The
           default value is 1. This option is deprecated, setting higher values should no longer
           be necessary and is not recommended.

       show
           When set to 1, a green rectangle is drawn on the screen to simplify finding the right
           x, y, w, and h parameters.  The default value is 0.

           The rectangle is drawn on the outermost pixels which will be (partly) replaced with
           interpolated values. The values of the next pixels immediately outside this rectangle
           in each direction will be used to compute the interpolated pixel values inside the
           rectangle.

       Examples

       ·   Set a rectangle covering the area with top left corner coordinates 0,0 and size
           100x77, and a band of size 10:

                   delogo=x=0:y=0:w=100:h=77:band=10

   deshake
       Attempt to fix small changes in horizontal and/or vertical shift. This filter helps remove
       camera shake from hand-holding a camera, bumping a tripod, moving on a vehicle, etc.

       The filter accepts the following options:

       x
       y
       w
       h   Specify a rectangular area where to limit the search for motion vectors.  If desired
           the search for motion vectors can be limited to a rectangular area of the frame
           defined by its top left corner, width and height. These parameters have the same
           meaning as the drawbox filter which can be used to visualise the position of the
           bounding box.

           This is useful when simultaneous movement of subjects within the frame might be
           confused for camera motion by the motion vector search.

           If any or all of x, y, w and h are set to -1 then the full frame is used. This allows
           later options to be set without specifying the bounding box for the motion vector
           search.

           Default - search the whole frame.

       rx
       ry  Specify the maximum extent of movement in x and y directions in the range 0-64 pixels.
           Default 16.

       edge
           Specify how to generate pixels to fill blanks at the edge of the frame. Available
           values are:

           blank, 0
               Fill zeroes at blank locations

           original, 1
               Original image at blank locations

           clamp, 2
               Extruded edge value at blank locations

           mirror, 3
               Mirrored edge at blank locations

           Default value is mirror.

       blocksize
           Specify the blocksize to use for motion search. Range 4-128 pixels, default 8.

       contrast
           Specify the contrast threshold for blocks. Only blocks with more than the specified
           contrast (difference between darkest and lightest pixels) will be considered. Range
           1-255, default 125.

       search
           Specify the search strategy. Available values are:

           exhaustive, 0
               Set exhaustive search

           less, 1
               Set less exhaustive search.

           Default value is exhaustive.

       filename
           If set then a detailed log of the motion search is written to the specified file.

       opencl
           If set to 1, specify using OpenCL capabilities, only available if FFmpeg was
           configured with "--enable-opencl". Default value is 0.

   detelecine
       Apply an exact inverse of the telecine operation. It requires a predefined pattern
       specified using the pattern option which must be the same as that passed to the telecine
       filter.

       This filter accepts the following options:

       first_field
           top, t
               top field first

           bottom, b
               bottom field first The default value is "top".

       pattern
           A string of numbers representing the pulldown pattern you wish to apply.  The default
           value is 23.

       start_frame
           A number representing position of the first frame with respect to the telecine
           pattern. This is to be used if the stream is cut. The default value is 0.

   dilation
       Apply dilation effect to the video.

       This filter replaces the pixel by the local(3x3) maximum.

       It accepts the following options:

       threshold0
       threshold1
       threshold2
       threshold3
           Limit the maximum change for each plane, default is 65535.  If 0, plane will remain
           unchanged.

       coordinates
           Flag which specifies the pixel to refer to. Default is 255 i.e. all eight pixels are
           used.

           Flags to local 3x3 coordinates maps like this:

               1 2 3
               4   5
               6 7 8

   displace
       Displace pixels as indicated by second and third input stream.

       It takes three input streams and outputs one stream, the first input is the source, and
       second and third input are displacement maps.

       The second input specifies how much to displace pixels along the x-axis, while the third
       input specifies how much to displace pixels along the y-axis.  If one of displacement map
       streams terminates, last frame from that displacement map will be used.

       Note that once generated, displacements maps can be reused over and over again.

       A description of the accepted options follows.

       edge
           Set displace behavior for pixels that are out of range.

           Available values are:

           blank
               Missing pixels are replaced by black pixels.

           smear
               Adjacent pixels will spread out to replace missing pixels.

           wrap
               Out of range pixels are wrapped so they point to pixels of other side.

           Default is smear.

       Examples

       ·   Add ripple effect to rgb input of video size hd720:

                   ffmpeg -i INPUT -f lavfi -i nullsrc=s=hd720,lutrgb=128:128:128 -f lavfi -i nullsrc=s=hd720,geq='r=128+30*sin(2*PI*X/400+T):g=128+30*sin(2*PI*X/400+T):b=128+30*sin(2*PI*X/400+T)' -lavfi '[0][1][2]displace' OUTPUT

       ·   Add wave effect to rgb input of video size hd720:

                   ffmpeg -i INPUT -f lavfi -i nullsrc=hd720,geq='r=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):g=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):b=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T))' -lavfi '[1]split[x][y],[0][x][y]displace' OUTPUT

   drawbox
       Draw a colored box on the input image.

       It accepts the following parameters:

       x
       y   The expressions which specify the top left corner coordinates of the box. It defaults
           to 0.

       width, w
       height, h
           The expressions which specify the width and height of the box; if 0 they are
           interpreted as the input width and height. It defaults to 0.

       color, c
           Specify the color of the box to write. For the general syntax of this option, check
           the "Color" section in the ffmpeg-utils manual. If the special value "invert" is used,
           the box edge color is the same as the video with inverted luma.

       thickness, t
           The expression which sets the thickness of the box edge. Default value is 3.

           See below for the list of accepted constants.

       The parameters for x, y, w and h and t are expressions containing the following constants:

       dar The input display aspect ratio, it is the same as (w / h) * sar.

       hsub
       vsub
           horizontal and vertical chroma subsample values. For example for the pixel format
           "yuv422p" hsub is 2 and vsub is 1.

       in_h, ih
       in_w, iw
           The input width and height.

       sar The input sample aspect ratio.

       x
       y   The x and y offset coordinates where the box is drawn.

       w
       h   The width and height of the drawn box.

       t   The thickness of the drawn box.

           These constants allow the x, y, w, h and t expressions to refer to each other, so you
           may for example specify "y=x/dar" or "h=w/dar".

       Examples

       ·   Draw a black box around the edge of the input image:

                   drawbox

       ·   Draw a box with color red and an opacity of 50%:

                   drawbox=10:20:200:60:red@0.5

           The previous example can be specified as:

                   drawbox=x=10:y=20:w=200:h=60:color=red@0.5

       ·   Fill the box with pink color:

                   drawbox=x=10:y=10:w=100:h=100:color=pink@0.5:t=max

       ·   Draw a 2-pixel red 2.40:1 mask:

                   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

   drawgrid
       Draw a grid on the input image.

       It accepts the following parameters:

       x
       y   The expressions which specify the coordinates of some point of grid intersection
           (meant to configure offset). Both default to 0.

       width, w
       height, h
           The expressions which specify the width and height of the grid cell, if 0 they are
           interpreted as the input width and height, respectively, minus "thickness", so image
           gets framed. Default to 0.

       color, c
           Specify the color of the grid. For the general syntax of this option, check the
           "Color" section in the ffmpeg-utils manual. If the special value "invert" is used, the
           grid color is the same as the video with inverted luma.

       thickness, t
           The expression which sets the thickness of the grid line. Default value is 1.

           See below for the list of accepted constants.

       The parameters for x, y, w and h and t are expressions containing the following constants:

       dar The input display aspect ratio, it is the same as (w / h) * sar.

       hsub
       vsub
           horizontal and vertical chroma subsample values. For example for the pixel format
           "yuv422p" hsub is 2 and vsub is 1.

       in_h, ih
       in_w, iw
           The input grid cell width and height.

       sar The input sample aspect ratio.

       x
       y   The x and y coordinates of some point of grid intersection (meant to configure
           offset).

       w
       h   The width and height of the drawn cell.

       t   The thickness of the drawn cell.

           These constants allow the x, y, w, h and t expressions to refer to each other, so you
           may for example specify "y=x/dar" or "h=w/dar".

       Examples

       ·   Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an
           opacity of 50%:

                   drawgrid=width=100:height=100:thickness=2:color=red@0.5

       ·   Draw a white 3x3 grid with an opacity of 50%:

                   drawgrid=w=iw/3:h=ih/3:t=2:c=white@0.5

   drawtext
       Draw a text string or text from a specified file on top of a video, using the libfreetype
       library.

       To enable compilation of this filter, you need to configure FFmpeg with
       "--enable-libfreetype".  To enable default font fallback and the font option you need to
       configure FFmpeg with "--enable-libfontconfig".  To enable the text_shaping option, you
       need to configure FFmpeg with "--enable-libfribidi".

       Syntax

       It accepts the following parameters:

       box Used to draw a box around text using the background color.  The value must be either 1
           (enable) or 0 (disable).  The default value of box is 0.

       boxborderw
           Set the width of the border to be drawn around the box using boxcolor.  The default
           value of boxborderw is 0.

       boxcolor
           The color to be used for drawing box around text. For the syntax of this option, check
           the "Color" section in the ffmpeg-utils manual.

           The default value of boxcolor is "white".

       line_spacing
           Set the line spacing in pixels of the border to be drawn around the box using box.
           The default value of line_spacing is 0.

       borderw
           Set the width of the border to be drawn around the text using bordercolor.  The
           default value of borderw is 0.

       bordercolor
           Set the color to be used for drawing border around text. For the syntax of this
           option, check the "Color" section in the ffmpeg-utils manual.

           The default value of bordercolor is "black".

       expansion
           Select how the text is expanded. Can be either "none", "strftime" (deprecated) or
           "normal" (default). See the drawtext_expansion, Text expansion section below for
           details.

       basetime
           Set a start time for the count. Value is in microseconds. Only applied in the
           deprecated strftime expansion mode. To emulate in normal expansion mode use the "pts"
           function, supplying the start time (in seconds) as the second argument.

       fix_bounds
           If true, check and fix text coords to avoid clipping.

       fontcolor
           The color to be used for drawing fonts. For the syntax of this option, check the
           "Color" section in the ffmpeg-utils manual.

           The default value of fontcolor is "black".

       fontcolor_expr
           String which is expanded the same way as text to obtain dynamic fontcolor value. By
           default this option has empty value and is not processed. When this option is set, it
           overrides fontcolor option.

       font
           The font family to be used for drawing text. By default Sans.

       fontfile
           The font file to be used for drawing text. The path must be included.  This parameter
           is mandatory if the fontconfig support is disabled.

       alpha
           Draw the text applying alpha blending. The value can be a number between 0.0 and 1.0.
           The expression accepts the same variables x, y as well.  The default value is 1.
           Please see fontcolor_expr.

       fontsize
           The font size to be used for drawing text.  The default value of fontsize is 16.

       text_shaping
           If set to 1, attempt to shape the text (for example, reverse the order of right-to-
           left text and join Arabic characters) before drawing it.  Otherwise, just draw the
           text exactly as given.  By default 1 (if supported).

       ft_load_flags
           The flags to be used for loading the fonts.

           The flags map the corresponding flags supported by libfreetype, and are a combination
           of the following values:

           default
           no_scale
           no_hinting
           render
           no_bitmap
           vertical_layout
           force_autohint
           crop_bitmap
           pedantic
           ignore_global_advance_width
           no_recurse
           ignore_transform
           monochrome
           linear_design
           no_autohint

           Default value is "default".

           For more information consult the documentation for the FT_LOAD_* libfreetype flags.

       shadowcolor
           The color to be used for drawing a shadow behind the drawn text. For the syntax of
           this option, check the "Color" section in the ffmpeg-utils manual.

           The default value of shadowcolor is "black".

       shadowx
       shadowy
           The x and y offsets for the text shadow position with respect to the position of the
           text. They can be either positive or negative values. The default value for both is
           "0".

       start_number
           The starting frame number for the n/frame_num variable. The default value is "0".

       tabsize
           The size in number of spaces to use for rendering the tab.  Default value is 4.

       timecode
           Set the initial timecode representation in "hh:mm:ss[:;.]ff" format. It can be used
           with or without text parameter. timecode_rate option must be specified.

       timecode_rate, rate, r
           Set the timecode frame rate (timecode only).

       tc24hmax
           If set to 1, the output of the timecode option will wrap around at 24 hours.  Default
           is 0 (disabled).

       text
           The text string to be drawn. The text must be a sequence of UTF-8 encoded characters.
           This parameter is mandatory if no file is specified with the parameter textfile.

       textfile
           A text file containing text to be drawn. The text must be a sequence of UTF-8 encoded
           characters.

           This parameter is mandatory if no text string is specified with the parameter text.

           If both text and textfile are specified, an error is thrown.

       reload
           If set to 1, the textfile will be reloaded before each frame.  Be sure to update it
           atomically, or it may be read partially, or even fail.

       x
       y   The expressions which specify the offsets where text will be drawn within the video
           frame. They are relative to the top/left border of the output image.

           The default value of x and y is "0".

           See below for the list of accepted constants and functions.

       The parameters for x and y are expressions containing the following constants and
       functions:

       dar input display aspect ratio, it is the same as (w / h) * sar

       hsub
       vsub
           horizontal and vertical chroma subsample values. For example for the pixel format
           "yuv422p" hsub is 2 and vsub is 1.

       line_h, lh
           the height of each text line

       main_h, h, H
           the input height

       main_w, w, W
           the input width

       max_glyph_a, ascent
           the maximum distance from the baseline to the highest/upper grid coordinate used to
           place a glyph outline point, for all the rendered glyphs.  It is a positive value, due
           to the grid's orientation with the Y axis upwards.

       max_glyph_d, descent
           the maximum distance from the baseline to the lowest grid coordinate used to place a
           glyph outline point, for all the rendered glyphs.  This is a negative value, due to
           the grid's orientation, with the Y axis upwards.

       max_glyph_h
           maximum glyph height, that is the maximum height for all the glyphs contained in the
           rendered text, it is equivalent to ascent - descent.

       max_glyph_w
           maximum glyph width, that is the maximum width for all the glyphs contained in the
           rendered text

       n   the number of input frame, starting from 0

       rand(min, max)
           return a random number included between min and max

       sar The input sample aspect ratio.

       t   timestamp expressed in seconds, NAN if the input timestamp is unknown

       text_h, th
           the height of the rendered text

       text_w, tw
           the width of the rendered text

       x
       y   the x and y offset coordinates where the text is drawn.

           These parameters allow the x and y expressions to refer each other, so you can for
           example specify "y=x/dar".

       Text expansion

       If expansion is set to "strftime", the filter recognizes strftime() sequences in the
       provided text and expands them accordingly. Check the documentation of strftime(). This
       feature is deprecated.

       If expansion is set to "none", the text is printed verbatim.

       If expansion is set to "normal" (which is the default), the following expansion mechanism
       is used.

       The backslash character \, followed by any character, always expands to the second
       character.

       Sequences of the form "%{...}" are expanded. The text between the braces is a function
       name, possibly followed by arguments separated by ':'.  If the arguments contain special
       characters or delimiters (':' or '}'), they should be escaped.

       Note that they probably must also be escaped as the value for the text option in the
       filter argument string and as the filter argument in the filtergraph description, and
       possibly also for the shell, that makes up to four levels of escaping; using a text file
       avoids these problems.

       The following functions are available:

       expr, e
           The expression evaluation result.

           It must take one argument specifying the expression to be evaluated, which accepts the
           same constants and functions as the x and y values. Note that not all constants should
           be used, for example the text size is not known when evaluating the expression, so the
           constants text_w and text_h will have an undefined value.

       expr_int_format, eif
           Evaluate the expression's value and output as formatted integer.

           The first argument is the expression to be evaluated, just as for the expr function.
           The second argument specifies the output format. Allowed values are x, X, d and u.
           They are treated exactly as in the "printf" function.  The third parameter is optional
           and sets the number of positions taken by the output.  It can be used to add padding
           with zeros from the left.

       gmtime
           The time at which the filter is running, expressed in UTC.  It can accept an argument:
           a strftime() format string.

       localtime
           The time at which the filter is running, expressed in the local time zone.  It can
           accept an argument: a strftime() format string.

       metadata
           Frame metadata. Takes one or two arguments.

           The first argument is mandatory and specifies the metadata key.

           The second argument is optional and specifies a default value, used when the metadata
           key is not found or empty.

       n, frame_num
           The frame number, starting from 0.

       pict_type
           A 1 character description of the current picture type.

       pts The timestamp of the current frame.  It can take up to three arguments.

           The first argument is the format of the timestamp; it defaults to "flt" for seconds as
           a decimal number with microsecond accuracy; "hms" stands for a formatted
           [-]HH:MM:SS.mmm timestamp with millisecond accuracy.  "gmtime" stands for the
           timestamp of the frame formatted as UTC time; "localtime" stands for the timestamp of
           the frame formatted as local time zone time.

           The second argument is an offset added to the timestamp.

           If the format is set to "localtime" or "gmtime", a third argument may be supplied: a
           strftime() format string.  By default, YYYY-MM-DD HH:MM:SS format will be used.

       Examples

       ·   Draw "Test Text" with font FreeSerif, using the default values for the optional
           parameters.

                   drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"

       ·   Draw 'Test Text' with font FreeSerif of size 24 at position x=100 and y=50 (counting
           from the top-left corner of the screen), text is yellow with a red box around it. Both
           the text and the box have an opacity of 20%.

                   drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
                             x=100: y=50: fontsize=24: fontcolor=yellow@0.2: box=1: boxcolor=red@0.2"

           Note that the double quotes are not necessary if spaces are not used within the
           parameter list.

       ·   Show the text at the center of the video frame:

                   drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h)/2"

       ·   Show the text at a random position, switching to a new position every 30 seconds:

                   drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=if(eq(mod(t\,30)\,0)\,rand(0\,(w-text_w))\,x):y=if(eq(mod(t\,30)\,0)\,rand(0\,(h-text_h))\,y)"

       ·   Show a text line sliding from right to left in the last row of the video frame. The
           file LONG_LINE is assumed to contain a single line with no newlines.

                   drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"

       ·   Show the content of file CREDITS off the bottom of the frame and scroll up.

                   drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"

       ·   Draw a single green letter "g", at the center of the input video.  The glyph baseline
           is placed at half screen height.

                   drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"

       ·   Show text for 1 second every 3 seconds:

                   drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"

       ·   Use fontconfig to set the font. Note that the colons need to be escaped.

                   drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'

       ·   Print the date of a real-time encoding (see strftime(3)):

                   drawtext='fontfile=FreeSans.ttf:text=%{localtime\:%a %b %d %Y}'

       ·   Show text fading in and out (appearing/disappearing):

                   #!/bin/sh
                   DS=1.0 # display start
                   DE=10.0 # display end
                   FID=1.5 # fade in duration
                   FOD=5 # fade out duration
                   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 }"

       ·   Horizontally align multiple separate texts. Note that max_glyph_a and the fontsize
           value are included in the y offset.

                   drawtext=fontfile=FreeSans.ttf:text=DOG:fontsize=24:x=10:y=20+24-max_glyph_a,
                   drawtext=fontfile=FreeSans.ttf:text=cow:fontsize=24:x=80:y=20+24-max_glyph_a

       For more information about libfreetype, check: <http://www.freetype.org/>.

       For more information about fontconfig, check:
       <http://freedesktop.org/software/fontconfig/fontconfig-user.html>.

       For more information about libfribidi, check: <http://fribidi.org/>.

   edgedetect
       Detect and draw edges. The filter uses the Canny Edge Detection algorithm.

       The filter accepts the following options:

       low
       high
           Set low and high threshold values used by the Canny thresholding algorithm.

           The high threshold selects the "strong" edge pixels, which are then connected through
           8-connectivity with the "weak" edge pixels selected by the low threshold.

           low and high threshold values must be chosen in the range [0,1], and low should be
           lesser or equal to high.

           Default value for low is "20/255", and default value for high is "50/255".

       mode
           Define the drawing mode.

           wires
               Draw white/gray wires on black background.

           colormix
               Mix the colors to create a paint/cartoon effect.

           Default value is wires.

       Examples

       ·   Standard edge detection with custom values for the hysteresis thresholding:

                   edgedetect=low=0.1:high=0.4

       ·   Painting effect without thresholding:

                   edgedetect=mode=colormix:high=0

   eq
       Set brightness, contrast, saturation and approximate gamma adjustment.

       The filter accepts the following options:

       contrast
           Set the contrast expression. The value must be a float value in range "-2.0" to 2.0.
           The default value is "1".

       brightness
           Set the brightness expression. The value must be a float value in range "-1.0" to 1.0.
           The default value is "0".

       saturation
           Set the saturation expression. The value must be a float in range 0.0 to 3.0. The
           default value is "1".

       gamma
           Set the gamma expression. The value must be a float in range 0.1 to 10.0.  The default
           value is "1".

       gamma_r
           Set the gamma expression for red. The value must be a float in range 0.1 to 10.0. The
           default value is "1".

       gamma_g
           Set the gamma expression for green. The value must be a float in range 0.1 to 10.0.
           The default value is "1".

       gamma_b
           Set the gamma expression for blue. The value must be a float in range 0.1 to 10.0. The
           default value is "1".

       gamma_weight
           Set the gamma weight expression. It can be used to reduce the effect of a high gamma
           value on bright image areas, e.g. keep them from getting overamplified and just plain
           white. The value must be a float in range 0.0 to 1.0. A value of 0.0 turns the gamma
           correction all the way down while 1.0 leaves it at its full strength. Default is "1".

       eval
           Set when the expressions for brightness, contrast, saturation and gamma expressions
           are evaluated.

           It accepts the following values:

           init
               only evaluate expressions once during the filter initialization or when a command
               is processed

           frame
               evaluate expressions for each incoming frame

           Default value is init.

       The expressions accept the following parameters:

       n   frame count of the input frame starting from 0

       pos byte position of the corresponding packet in the input file, NAN if unspecified

       r   frame rate of the input video, NAN if the input frame rate is unknown

       t   timestamp expressed in seconds, NAN if the input timestamp is unknown

       Commands

       The filter supports the following commands:

       contrast
           Set the contrast expression.

       brightness
           Set the brightness expression.

       saturation
           Set the saturation expression.

       gamma
           Set the gamma expression.

       gamma_r
           Set the gamma_r expression.

       gamma_g
           Set gamma_g expression.

       gamma_b
           Set gamma_b expression.

       gamma_weight
           Set gamma_weight expression.

           The command accepts the same syntax of the corresponding option.

           If the specified expression is not valid, it is kept at its current value.

   erosion
       Apply erosion effect to the video.

       This filter replaces the pixel by the local(3x3) minimum.

       It accepts the following options:

       threshold0
       threshold1
       threshold2
       threshold3
           Limit the maximum change for each plane, default is 65535.  If 0, plane will remain
           unchanged.

       coordinates
           Flag which specifies the pixel to refer to. Default is 255 i.e. all eight pixels are
           used.

           Flags to local 3x3 coordinates maps like this:

               1 2 3
               4   5
               6 7 8

   extractplanes
       Extract color channel components from input video stream into separate grayscale video
       streams.

       The filter accepts the following option:

       planes
           Set plane(s) to extract.

           Available values for planes are:

           y
           u
           v
           a
           r
           g
           b

           Choosing planes not available in the input will result in an error.  That means you
           cannot select "r", "g", "b" planes with "y", "u", "v" planes at same time.

       Examples

       ·   Extract luma, u and v color channel component from input video frame into 3 grayscale
           outputs:

                   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

   elbg
       Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.

       For each input image, the filter will compute the optimal mapping from the input to the
       output given the codebook length, that is the number of distinct output colors.

       This filter accepts the following options.

       codebook_length, l
           Set codebook length. The value must be a positive integer, and represents the number
           of distinct output colors. Default value is 256.

       nb_steps, n
           Set the maximum number of iterations to apply for computing the optimal mapping. The
           higher the value the better the result and the higher the computation time. Default
           value is 1.

       seed, s
           Set a random seed, must be an integer included between 0 and UINT32_MAX. If not
           specified, or if explicitly set to -1, the filter will try to use a good random seed
           on a best effort basis.

       pal8
           Set pal8 output pixel format. This option does not work with codebook length greater
           than 256.

   fade
       Apply a fade-in/out effect to the input video.

       It accepts the following parameters:

       type, t
           The effect type can be either "in" for a fade-in, or "out" for a fade-out effect.
           Default is "in".

       start_frame, s
           Specify the number of the frame to start applying the fade effect at. Default is 0.

       nb_frames, n
           The number of frames that the fade effect lasts. At the end of the fade-in effect, the
           output video will have the same intensity as the input video.  At the end of the fade-
           out transition, the output video will be filled with the selected color.  Default is
           25.

       alpha
           If set to 1, fade only alpha channel, if one exists on the input.  Default value is 0.

       start_time, st
           Specify the timestamp (in seconds) of the frame to start to apply the fade effect. If
           both start_frame and start_time are specified, the fade will start at whichever comes
           last.  Default is 0.

       duration, d
           The number of seconds for which the fade effect has to last. At the end of the fade-in
           effect the output video will have the same intensity as the input video, at the end of
           the fade-out transition the output video will be filled with the selected color.  If
           both duration and nb_frames are specified, duration is used. Default is 0 (nb_frames
           is used by default).

       color, c
           Specify the color of the fade. Default is "black".

       Examples

       ·   Fade in the first 30 frames of video:

                   fade=in:0:30

           The command above is equivalent to:

                   fade=t=in:s=0:n=30

       ·   Fade out the last 45 frames of a 200-frame video:

                   fade=out:155:45
                   fade=type=out:start_frame=155:nb_frames=45

       ·   Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:

                   fade=in:0:25, fade=out:975:25

       ·   Make the first 5 frames yellow, then fade in from frame 5-24:

                   fade=in:5:20:color=yellow

       ·   Fade in alpha over first 25 frames of video:

                   fade=in:0:25:alpha=1

       ·   Make the first 5.5 seconds black, then fade in for 0.5 seconds:

                   fade=t=in:st=5.5:d=0.5

   fftfilt
       Apply arbitrary expressions to samples in frequency domain

       dc_Y
           Adjust the dc value (gain) of the luma plane of the image. The filter accepts an
           integer value in range 0 to 1000. The default value is set to 0.

       dc_U
           Adjust the dc value (gain) of the 1st chroma plane of the image. The filter accepts an
           integer value in range 0 to 1000. The default value is set to 0.

       dc_V
           Adjust the dc value (gain) of the 2nd chroma plane of the image. The filter accepts an
           integer value in range 0 to 1000. The default value is set to 0.

       weight_Y
           Set the frequency domain weight expression for the luma plane.

       weight_U
           Set the frequency domain weight expression for the 1st chroma plane.

       weight_V
           Set the frequency domain weight expression for the 2nd chroma plane.

           The filter accepts the following variables:

       X
       Y   The coordinates of the current sample.

       W
       H   The width and height of the image.

       Examples

       ·   High-pass:

                   fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'

       ·   Low-pass:

                   fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'

       ·   Sharpen:

                   fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'

       ·   Blur:

                   fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'

   field
       Extract a single field from an interlaced image using stride arithmetic to avoid wasting
       CPU time. The output frames are marked as non-interlaced.

       The filter accepts the following options:

       type
           Specify whether to extract the top (if the value is 0 or "top") or the bottom field
           (if the value is 1 or "bottom").

   fieldhint
       Create new frames by copying the top and bottom fields from surrounding frames supplied as
       numbers by the hint file.

       hint
           Set file containing hints: absolute/relative frame numbers.

           There must be one line for each frame in a clip. Each line must contain two numbers
           separated by the comma, optionally followed by "-" or "+".  Numbers supplied on each
           line of file can not be out of [N-1,N+1] where N is current frame number for
           "absolute" mode or out of [-1, 1] range for "relative" mode. First number tells from
           which frame to pick up top field and second number tells from which frame to pick up
           bottom field.

           If optionally followed by "+" output frame will be marked as interlaced, else if
           followed by "-" output frame will be marked as progressive, else it will be marked
           same as input frame.  If line starts with "#" or ";" that line is skipped.

       mode
           Can be item "absolute" or "relative". Default is "absolute".

       Example of first several lines of "hint" file for "relative" mode:

               0,0 - # first frame
               1,0 - # second frame, use third's frame top field and second's frame bottom field
               1,0 - # third frame, use fourth's frame top field and third's frame bottom field
               1,0 -
               0,0 -
               0,0 -
               1,0 -
               1,0 -
               1,0 -
               0,0 -
               0,0 -
               1,0 -
               1,0 -
               1,0 -
               0,0 -

   fieldmatch
       Field matching filter for inverse telecine. It is meant to reconstruct the progressive
       frames from a telecined stream. The filter does not drop duplicated frames, so to achieve
       a complete inverse telecine "fieldmatch" needs to be followed by a decimation filter such
       as decimate in the filtergraph.

       The separation of the field matching and the decimation is notably motivated by the
       possibility of inserting a de-interlacing filter fallback between the two.  If the source
       has mixed telecined and real interlaced content, "fieldmatch" will not be able to match
       fields for the interlaced parts.  But these remaining combed frames will be marked as
       interlaced, and thus can be de-interlaced by a later filter such as yadif before
       decimation.

       In addition to the various configuration options, "fieldmatch" can take an optional second
       stream, activated through the ppsrc option. If enabled, the frames reconstruction will be
       based on the fields and frames from this second stream. This allows the first input to be
       pre-processed in order to help the various algorithms of the filter, while keeping the
       output lossless (assuming the fields are matched properly). Typically, a field-aware
       denoiser, or brightness/contrast adjustments can help.

       Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project) and
       VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from which "fieldmatch"
       is based on. While the semantic and usage are very close, some behaviour and options names
       can differ.

       The decimate filter currently only works for constant frame rate input.  If your input has
       mixed telecined (30fps) and progressive content with a lower framerate like 24fps use the
       following filterchain to produce the necessary cfr stream:
       "dejudder,fps=30000/1001,fieldmatch,decimate".

       The filter accepts the following options:

       order
           Specify the assumed field order of the input stream. Available values are:

           auto
               Auto detect parity (use FFmpeg's internal parity value).

           bff Assume bottom field first.

           tff Assume top field first.

           Note that it is sometimes recommended not to trust the parity announced by the stream.

           Default value is auto.

       mode
           Set the matching mode or strategy to use. pc mode is the safest in the sense that it
           won't risk creating jerkiness due to duplicate frames when possible, but if there are
           bad edits or blended fields it will end up outputting combed frames when a good match
           might actually exist. On the other hand, pcn_ub mode is the most risky in terms of
           creating jerkiness, but will almost always find a good frame if there is one. The
           other values are all somewhere in between pc and pcn_ub in terms of risking jerkiness
           and creating duplicate frames versus finding good matches in sections with bad edits,
           orphaned fields, blended fields, etc.

           More details about p/c/n/u/b are available in p/c/n/u/b meaning section.

           Available values are:

           pc  2-way matching (p/c)

           pc_n
               2-way matching, and trying 3rd match if still combed (p/c + n)

           pc_u
               2-way matching, and trying 3rd match (same order) if still combed (p/c + u)

           pc_n_ub
               2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
               still combed (p/c + n + u/b)

           pcn 3-way matching (p/c/n)

           pcn_ub
               3-way matching, and trying 4th/5th matches if all 3 of the original matches are
               detected as combed (p/c/n + u/b)

           The parenthesis at the end indicate the matches that would be used for that mode
           assuming order=tff (and field on auto or top).

           In terms of speed pc mode is by far the fastest and pcn_ub is the slowest.

           Default value is pc_n.

       ppsrc
           Mark the main input stream as a pre-processed input, and enable the secondary input
           stream as the clean source to pick the fields from. See the filter introduction for
           more details. It is similar to the clip2 feature from VFM/TFM.

           Default value is 0 (disabled).

       field
           Set the field to match from. It is recommended to set this to the same value as order
           unless you experience matching failures with that setting. In certain circumstances
           changing the field that is used to match from can have a large impact on matching
           performance. Available values are:

           auto
               Automatic (same value as order).

           bottom
               Match from the bottom field.

           top Match from the top field.

           Default value is auto.

       mchroma
           Set whether or not chroma is included during the match comparisons. In most cases it
           is recommended to leave this enabled. You should set this to 0 only if your clip has
           bad chroma problems such as heavy rainbowing or other artifacts. Setting this to 0
           could also be used to speed things up at the cost of some accuracy.

           Default value is 1.

       y0
       y1  These define an exclusion band which excludes the lines between y0 and y1 from being
           included in the field matching decision. An exclusion band can be used to ignore
           subtitles, a logo, or other things that may interfere with the matching. y0 sets the
           starting scan line and y1 sets the ending line; all lines in between y0 and y1
           (including y0 and y1) will be ignored. Setting y0 and y1 to the same value will
           disable the feature.  y0 and y1 defaults to 0.

       scthresh
           Set the scene change detection threshold as a percentage of maximum change on the luma
           plane. Good values are in the "[8.0, 14.0]" range. Scene change detection is only
           relevant in case combmatch=sc.  The range for scthresh is "[0.0, 100.0]".

           Default value is 12.0.

       combmatch
           When combatch is not none, "fieldmatch" will take into account the combed scores of
           matches when deciding what match to use as the final match. Available values are:

           none
               No final matching based on combed scores.

           sc  Combed scores are only used when a scene change is detected.

           full
               Use combed scores all the time.

           Default is sc.

       combdbg
           Force "fieldmatch" to calculate the combed metrics for certain matches and print them.
           This setting is known as micout in TFM/VFM vocabulary.  Available values are:

           none
               No forced calculation.

           pcn Force p/c/n calculations.

           pcnub
               Force p/c/n/u/b calculations.

           Default value is none.

       cthresh
           This is the area combing threshold used for combed frame detection. This essentially
           controls how "strong" or "visible" combing must be to be detected.  Larger values mean
           combing must be more visible and smaller values mean combing can be less visible or
           strong and still be detected. Valid settings are from "-1" (every pixel will be
           detected as combed) to 255 (no pixel will be detected as combed). This is basically a
           pixel difference value. A good range is "[8, 12]".

           Default value is 9.

       chroma
           Sets whether or not chroma is considered in the combed frame decision.  Only disable
           this if your source has chroma problems (rainbowing, etc.) that are causing problems
           for the combed frame detection with chroma enabled. Actually, using chroma=0 is
           usually more reliable, except for the case where there is chroma only combing in the
           source.

           Default value is 0.

       blockx
       blocky
           Respectively set the x-axis and y-axis size of the window used during combed frame
           detection. This has to do with the size of the area in which combpel pixels are
           required to be detected as combed for a frame to be declared combed. See the combpel
           parameter description for more info.  Possible values are any number that is a power
           of 2 starting at 4 and going up to 512.

           Default value is 16.

       combpel
           The number of combed pixels inside any of the blocky by blockx size blocks on the
           frame for the frame to be detected as combed. While cthresh controls how "visible" the
           combing must be, this setting controls "how much" combing there must be in any
           localized area (a window defined by the blockx and blocky settings) on the frame.
           Minimum value is 0 and maximum is "blocky x blockx" (at which point no frames will
           ever be detected as combed). This setting is known as MI in TFM/VFM vocabulary.

           Default value is 80.

       p/c/n/u/b meaning

       p/c/n

       We assume the following telecined stream:

               Top fields:     1 2 2 3 4
               Bottom fields:  1 2 3 4 4

       The numbers correspond to the progressive frame the fields relate to. Here, the first two
       frames are progressive, the 3rd and 4th are combed, and so on.

       When "fieldmatch" is configured to run a matching from bottom (field=bottom) this is how
       this input stream get transformed:

               Input stream:
                               T     1 2 2 3 4
                               B     1 2 3 4 4   <-- matching reference

               Matches:              c c n n c

               Output stream:
                               T     1 2 3 4 4
                               B     1 2 3 4 4

       As a result of the field matching, we can see that some frames get duplicated.  To perform
       a complete inverse telecine, you need to rely on a decimation filter after this operation.
       See for instance the decimate filter.

       The same operation now matching from top fields (field=top) looks like this:

               Input stream:
                               T     1 2 2 3 4   <-- matching reference
                               B     1 2 3 4 4

               Matches:              c c p p c

               Output stream:
                               T     1 2 2 3 4
                               B     1 2 2 3 4

       In these examples, we can see what p, c and n mean; basically, they refer to the frame and
       field of the opposite parity:

       *<p matches the field of the opposite parity in the previous frame>
       *<c matches the field of the opposite parity in the current frame>
       *<n matches the field of the opposite parity in the next frame>

       u/b

       The u and b matching are a bit special in the sense that they match from the opposite
       parity flag. In the following examples, we assume that we are currently matching the 2nd
       frame (Top:2, bottom:2). According to the match, a 'x' is placed above and below each
       matched fields.

       With bottom matching (field=bottom):

               Match:           c         p           n          b          u

                                x       x               x        x          x
                 Top          1 2 2     1 2 2       1 2 2      1 2 2      1 2 2
                 Bottom       1 2 3     1 2 3       1 2 3      1 2 3      1 2 3
                                x         x           x        x              x

               Output frames:
                                2          1          2          2          2
                                2          2          2          1          3

       With top matching (field=top):

               Match:           c         p           n          b          u

                                x         x           x        x              x
                 Top          1 2 2     1 2 2       1 2 2      1 2 2      1 2 2
                 Bottom       1 2 3     1 2 3       1 2 3      1 2 3      1 2 3
                                x       x               x        x          x

               Output frames:
                                2          2          2          1          2
                                2          1          3          2          2

       Examples

       Simple IVTC of a top field first telecined stream:

               fieldmatch=order=tff:combmatch=none, decimate

       Advanced IVTC, with fallback on yadif for still combed frames:

               fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate

   fieldorder
       Transform the field order of the input video.

       It accepts the following parameters:

       order
           The output field order. Valid values are tff for top field first or bff for bottom
           field first.

       The default value is tff.

       The transformation is done by shifting the picture content up or down by one line, and
       filling the remaining line with appropriate picture content.  This method is consistent
       with most broadcast field order converters.

       If the input video is not flagged as being interlaced, or it is already flagged as being
       of the required output field order, then this filter does not alter the incoming video.

       It is very useful when converting to or from PAL DV material, which is bottom field first.

       For example:

               ffmpeg -i in.vob -vf "fieldorder=bff" out.dv

   fifo, afifo
       Buffer input images and send them when they are requested.

       It is mainly useful when auto-inserted by the libavfilter framework.

       It does not take parameters.

   find_rect
       Find a rectangular object

       It accepts the following options:

       object
           Filepath of the object image, needs to be in gray8.

       threshold
           Detection threshold, default is 0.5.

       mipmaps
           Number of mipmaps, default is 3.

       xmin, ymin, xmax, ymax
           Specifies the rectangle in which to search.

       Examples

       ·   Generate a representative palette of a given video using ffmpeg:

                   ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv

   cover_rect
       Cover a rectangular object

       It accepts the following options:

       cover
           Filepath of the optional cover image, needs to be in yuv420.

       mode
           Set covering mode.

           It accepts the following values:

           cover
               cover it by the supplied image

           blur
               cover it by interpolating the surrounding pixels

           Default value is blur.

       Examples

       ·   Generate a representative palette of a given video using ffmpeg:

                   ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv

   format
       Convert the input video to one of the specified pixel formats.  Libavfilter will try to
       pick one that is suitable as input to the next filter.

       It accepts the following parameters:

       pix_fmts
           A '|'-separated list of pixel format names, such as "pix_fmts=yuv420p|monow|rgb24".

       Examples

       ·   Convert the input video to the yuv420p format

                   format=pix_fmts=yuv420p

           Convert the input video to any of the formats in the list

                   format=pix_fmts=yuv420p|yuv444p|yuv410p

   fps
       Convert the video to specified constant frame rate by duplicating or dropping frames as
       necessary.

       It accepts the following parameters:

       fps The desired output frame rate. The default is 25.

       round
           Rounding method.

           Possible values are:

           zero
               zero round towards 0

           inf round away from 0

           down
               round towards -infinity

           up  round towards +infinity

           near
               round to nearest

           The default is "near".

       start_time
           Assume the first PTS should be the given value, in seconds. This allows for
           padding/trimming at the start of stream. By default, no assumption is made about the
           first frame's expected PTS, so no padding or trimming is done.  For example, this
           could be set to 0 to pad the beginning with duplicates of the first frame if a video
           stream starts after the audio stream or to trim any frames with a negative PTS.

       Alternatively, the options can be specified as a flat string: fps[:round].

       See also the setpts filter.

       Examples

       ·   A typical usage in order to set the fps to 25:

                   fps=fps=25

       ·   Sets the fps to 24, using abbreviation and rounding method to round to nearest:

                   fps=fps=film:round=near

   framepack
       Pack two different video streams into a stereoscopic video, setting proper metadata on
       supported codecs. The two views should have the same size and framerate and processing
       will stop when the shorter video ends. Please note that you may conveniently adjust view
       properties with the scale and fps filters.

       It accepts the following parameters:

       format
           The desired packing format. Supported values are:

           sbs The views are next to each other (default).

           tab The views are on top of each other.

           lines
               The views are packed by line.

           columns
               The views are packed by column.

           frameseq
               The views are temporally interleaved.

       Some examples:

               # Convert left and right views into a frame-sequential video
               ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT

               # Convert views into a side-by-side video with the same output resolution as the input
               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

   framerate
       Change the frame rate by interpolating new video output frames from the source frames.

       This filter is not designed to function correctly with interlaced media. If you wish to
       change the frame rate of interlaced media then you are required to deinterlace before this
       filter and re-interlace after this filter.

       A description of the accepted options follows.

       fps Specify the output frames per second. This option can also be specified as a value
           alone. The default is 50.

       interp_start
           Specify the start of a range where the output frame will be created as a linear
           interpolation of two frames. The range is [0-255], the default is 15.

       interp_end
           Specify the end of a range where the output frame will be created as a linear
           interpolation of two frames. The range is [0-255], the default is 240.

       scene
           Specify the level at which a scene change is detected as a value between 0 and 100 to
           indicate a new scene; a low value reflects a low probability for the current frame to
           introduce a new scene, while a higher value means the current frame is more likely to
           be one.  The default is 7.

       flags
           Specify flags influencing the filter process.

           Available value for flags is:

           scene_change_detect, scd
               Enable scene change detection using the value of the option scene.  This flag is
               enabled by default.

   framestep
       Select one frame every N-th frame.

       This filter accepts the following option:

       step
           Select frame after every "step" frames.  Allowed values are positive integers higher
           than 0. Default value is 1.

   frei0r
       Apply a frei0r effect to the input video.

       To enable the compilation of this filter, you need to install the frei0r header and
       configure FFmpeg with "--enable-frei0r".

       It accepts the following parameters:

       filter_name
           The name of the frei0r effect to load. If the environment variable FREI0R_PATH is
           defined, the frei0r effect is searched for in each of the directories specified by the
           colon-separated list in FREI0R_PATH.  Otherwise, the standard frei0r paths are
           searched, in this order: HOME/.frei0r-1/lib/, /usr/local/lib/frei0r-1/,
           /usr/lib/frei0r-1/.

       filter_params
           A '|'-separated list of parameters to pass to the frei0r effect.

       A frei0r effect parameter can be a boolean (its value is either "y" or "n"), a double, a
       color (specified as R/G/B, where R, G, and B are floating point numbers between 0.0 and
       1.0, inclusive) or by a color description specified in the "Color" section in the ffmpeg-
       utils manual), a position (specified as X/Y, where X and Y are floating point numbers)
       and/or a string.

       The number and types of parameters depend on the loaded effect. If an effect parameter is
       not specified, the default value is set.

       Examples

       ·   Apply the distort0r effect, setting the first two double parameters:

                   frei0r=filter_name=distort0r:filter_params=0.5|0.01

       ·   Apply the colordistance effect, taking a color as the first parameter:

                   frei0r=colordistance:0.2/0.3/0.4
                   frei0r=colordistance:violet
                   frei0r=colordistance:0x112233

       ·   Apply the perspective effect, specifying the top left and top right image positions:

                   frei0r=perspective:0.2/0.2|0.8/0.2

       For more information, see <http://frei0r.dyne.org>

   fspp
       Apply fast and simple postprocessing. It is a faster version of spp.

       It splits (I)DCT into horizontal/vertical passes. Unlike the simple post- processing
       filter, one of them is performed once per block, not per pixel.  This allows for much
       higher speed.

       The filter accepts the following options:

       quality
           Set quality. This option defines the number of levels for averaging. It accepts an
           integer in the range 4-5. Default value is 4.

       qp  Force a constant quantization parameter. It accepts an integer in range 0-63.  If not
           set, the filter will use the QP from the video stream (if available).

       strength
           Set filter strength. It accepts an integer in range -15 to 32. Lower values mean more
           details but also more artifacts, while higher values make the image smoother but also
           blurrier. Default value is 0 X PSNR optimal.

       use_bframe_qp
           Enable the use of the QP from the B-Frames if set to 1. Using this option may cause
           flicker since the B-Frames have often larger QP. Default is 0 (not enabled).

   gblur
       Apply Gaussian blur filter.

       The filter accepts the following options:

       sigma
           Set horizontal sigma, standard deviation of Gaussian blur. Default is 0.5.

       steps
           Set number of steps for Gaussian approximation. Defauls is 1.

       planes
           Set which planes to filter. By default all planes are filtered.

       sigmaV
           Set vertical sigma, if negative it will be same as "sigma".  Default is "-1".

   geq
       The filter accepts the following options:

       lum_expr, lum
           Set the luminance expression.

       cb_expr, cb
           Set the chrominance blue expression.

       cr_expr, cr
           Set the chrominance red expression.

       alpha_expr, a
           Set the alpha expression.

       red_expr, r
           Set the red expression.

       green_expr, g
           Set the green expression.

       blue_expr, b
           Set the blue expression.

       The colorspace is selected according to the specified options. If one of the lum_expr,
       cb_expr, or cr_expr options is specified, the filter will automatically select a YCbCr
       colorspace. If one of the red_expr, green_expr, or blue_expr options is specified, it will
       select an RGB colorspace.

       If one of the chrominance expression is not defined, it falls back on the other one. If no
       alpha expression is specified it will evaluate to opaque value.  If none of chrominance
       expressions are specified, they will evaluate to the luminance expression.

       The expressions can use the following variables and functions:

       N   The sequential number of the filtered frame, starting from 0.

       X
       Y   The coordinates of the current sample.

       W
       H   The width and height of the image.

       SW
       SH  Width and height scale depending on the currently filtered plane. It is the ratio
           between the corresponding luma plane number of pixels and the current plane ones. E.g.
           for YUV4:2:0 the values are "1,1" for the luma plane, and "0.5,0.5" for chroma planes.

       T   Time of the current frame, expressed in seconds.

       p(x, y)
           Return the value of the pixel at location (x,y) of the current plane.

       lum(x, y)
           Return the value of the pixel at location (x,y) of the luminance plane.

       cb(x, y)
           Return the value of the pixel at location (x,y) of the blue-difference chroma plane.
           Return 0 if there is no such plane.

       cr(x, y)
           Return the value of the pixel at location (x,y) of the red-difference chroma plane.
           Return 0 if there is no such plane.

       r(x, y)
       g(x, y)
       b(x, y)
           Return the value of the pixel at location (x,y) of the red/green/blue component.
           Return 0 if there is no such component.

       alpha(x, y)
           Return the value of the pixel at location (x,y) of the alpha plane. Return 0 if there
           is no such plane.

       For functions, if x and y are outside the area, the value will be automatically clipped to
       the closer edge.

       Examples

       ·   Flip the image horizontally:

                   geq=p(W-X\,Y)

       ·   Generate a bidimensional sine wave, with angle "PI/3" and a wavelength of 100 pixels:

                   geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128

       ·   Generate a fancy enigmatic moving light:

                   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

       ·   Generate a quick emboss effect:

                   format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'

       ·   Modify RGB components depending on pixel position:

                   geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'

       ·   Create a radial gradient that is the same size as the input (also see the vignette
           filter):

                   geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray

   gradfun
       Fix the banding artifacts that are sometimes introduced into nearly flat regions by
       truncation to 8-bit color depth.  Interpolate the gradients that should go where the bands
       are, and dither them.

       It is designed for playback only.  Do not use it prior to lossy compression, because
       compression tends to lose the dither and bring back the bands.

       It accepts the following parameters:

       strength
           The maximum amount by which the filter will change any one pixel. This is also the
           threshold for detecting nearly flat regions. Acceptable values range from .51 to 64;
           the default value is 1.2. Out-of-range values will be clipped to the valid range.

       radius
           The neighborhood to fit the gradient to. A larger radius makes for smoother gradients,
           but also prevents the filter from modifying the pixels near detailed regions.
           Acceptable values are 8-32; the default value is 16. Out-of-range values will be
           clipped to the valid range.

       Alternatively, the options can be specified as a flat string: strength[:radius]

       Examples

       ·   Apply the filter with a 3.5 strength and radius of 8:

                   gradfun=3.5:8

       ·   Specify radius, omitting the strength (which will fall-back to the default value):

                   gradfun=radius=8

   haldclut
       Apply a Hald CLUT to a video stream.

       First input is the video stream to process, and second one is the Hald CLUT.  The Hald
       CLUT input can be a simple picture or a complete video stream.

       The filter accepts the following options:

       shortest
           Force termination when the shortest input terminates. Default is 0.

       repeatlast
           Continue applying the last CLUT after the end of the stream. A value of 0 disable the
           filter after the last frame of the CLUT is reached.  Default is 1.

       "haldclut" also has the same interpolation options as lut3d (both filters share the same
       internals).

       More information about the Hald CLUT can be found on Eskil Steenberg's website (Hald CLUT
       author) at <http://www.quelsolaar.com/technology/clut.html>.

       Workflow examples

       Hald CLUT video stream

       Generate an identity Hald CLUT stream altered with various effects:

               ffmpeg -f lavfi -i B<haldclutsrc>=8 -vf "hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process" -t 10 -c:v ffv1 clut.nut

       Note: make sure you use a lossless codec.

       Then use it with "haldclut" to apply it on some random stream:

               ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv

       The Hald CLUT will be applied to the 10 first seconds (duration of clut.nut), then the
       latest picture of that CLUT stream will be applied to the remaining frames of the
       "mandelbrot" stream.

       Hald CLUT with preview

       A Hald CLUT is supposed to be a squared image of "Level*Level*Level" by
       "Level*Level*Level" pixels. For a given Hald CLUT, FFmpeg will select the biggest possible
       square starting at the top left of the picture. The remaining padding pixels (bottom or
       right) will be ignored. This area can be used to add a preview of the Hald CLUT.

       Typically, the following generated Hald CLUT will be supported by the "haldclut" filter:

               ffmpeg -f lavfi -i B<haldclutsrc>=8 -vf "
                  pad=iw+320 [padded_clut];
                  smptebars=s=320x256, split [a][b];
                  [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
                  [main][b] overlay=W-320" -frames:v 1 clut.png

       It contains the original and a preview of the effect of the CLUT: SMPTE color bars are
       displayed on the right-top, and below the same color bars processed by the color changes.

       Then, the effect of this Hald CLUT can be visualized with:

               ffplay input.mkv -vf "movie=clut.png, [in] haldclut"

   hflip
       Flip the input video horizontally.

       For example, to horizontally flip the input video with ffmpeg:

               ffmpeg -i in.avi -vf "hflip" out.avi

   histeq
       This filter applies a global color histogram equalization on a per-frame basis.

       It can be used to correct video that has a compressed range of pixel intensities.  The
       filter redistributes the pixel intensities to equalize their distribution across the
       intensity range. It may be viewed as an "automatically adjusting contrast filter". This
       filter is useful only for correcting degraded or poorly captured source video.

       The filter accepts the following options:

       strength
           Determine the amount of equalization to be applied.  As the strength is reduced, the
           distribution of pixel intensities more-and-more approaches that of the input frame.
           The value must be a float number in the range [0,1] and defaults to 0.200.

       intensity
           Set the maximum intensity that can generated and scale the output values
           appropriately.  The strength should be set as desired and then the intensity can be
           limited if needed to avoid washing-out. The value must be a float number in the range
           [0,1] and defaults to 0.210.

       antibanding
           Set the antibanding level. If enabled the filter will randomly vary the luminance of
           output pixels by a small amount to avoid banding of the histogram. Possible values are
           "none", "weak" or "strong". It defaults to "none".

   histogram
       Compute and draw a color distribution histogram for the input video.

       The computed histogram is a representation of the color component distribution in an
       image.

       Standard histogram displays the color components distribution in an image.  Displays color
       graph for each color component. Shows distribution of the Y, U, V, A or R, G, B
       components, depending on input format, in the current frame. Below each graph a color
       component scale meter is shown.

       The filter accepts the following options:

       level_height
           Set height of level. Default value is 200.  Allowed range is [50, 2048].

       scale_height
           Set height of color scale. Default value is 12.  Allowed range is [0, 40].

       display_mode
           Set display mode.  It accepts the following values:

           parade
               Per color component graphs are placed below each other.

           overlay
               Presents information identical to that in the "parade", except that the graphs
               representing color components are superimposed directly over one another.

           Default is "parade".

       levels_mode
           Set mode. Can be either "linear", or "logarithmic".  Default is "linear".

       components
           Set what color components to display.  Default is 7.

       fgopacity
           Set foreground opacity. Default is 0.7.

       bgopacity
           Set background opacity. Default is 0.5.

       Examples

       ·   Calculate and draw histogram:

                   ffplay -i input -vf histogram

   hqdn3d
       This is a high precision/quality 3d denoise filter. It aims to reduce image noise,
       producing smooth images and making still images really still. It should enhance
       compressibility.

       It accepts the following optional parameters:

       luma_spatial
           A non-negative floating point number which specifies spatial luma strength.  It
           defaults to 4.0.

       chroma_spatial
           A non-negative floating point number which specifies spatial chroma strength.  It
           defaults to 3.0*luma_spatial/4.0.

       luma_tmp
           A floating point number which specifies luma temporal strength. It defaults to
           6.0*luma_spatial/4.0.

       chroma_tmp
           A floating point number which specifies chroma temporal strength. It defaults to
           luma_tmp*chroma_spatial/luma_spatial.

   hwupload_cuda
       Upload system memory frames to a CUDA device.

       It accepts the following optional parameters:

       device
           The number of the CUDA device to use

   hqx
       Apply a high-quality magnification filter designed for pixel art. This filter was
       originally created by Maxim Stepin.

       It accepts the following option:

       n   Set the scaling dimension: 2 for "hq2x", 3 for "hq3x" and 4 for "hq4x".  Default is 3.

   hstack
       Stack input videos horizontally.

       All streams must be of same pixel format and of same height.

       Note that this filter is faster than using overlay and pad filter to create same output.

       The filter accept the following option:

       inputs
           Set number of input streams. Default is 2.

       shortest
           If set to 1, force the output to terminate when the shortest input terminates. Default
           value is 0.

   hue
       Modify the hue and/or the saturation of the input.

       It accepts the following parameters:

       h   Specify the hue angle as a number of degrees. It accepts an expression, and defaults
           to "0".

       s   Specify the saturation in the [-10,10] range. It accepts an expression and defaults to
           "1".

       H   Specify the hue angle as a number of radians. It accepts an expression, and defaults
           to "0".

       b   Specify the brightness in the [-10,10] range. It accepts an expression and defaults to
           "0".

       h and H are mutually exclusive, and can't be specified at the same time.

       The b, h, H and s option values are expressions containing the following constants:

       n   frame count of the input frame starting from 0

       pts presentation timestamp of the input frame expressed in time base units

       r   frame rate of the input video, NAN if the input frame rate is unknown

       t   timestamp expressed in seconds, NAN if the input timestamp is unknown

       tb  time base of the input video

       Examples

       ·   Set the hue to 90 degrees and the saturation to 1.0:

                   hue=h=90:s=1

       ·   Same command but expressing the hue in radians:

                   hue=H=PI/2:s=1

       ·   Rotate hue and make the saturation swing between 0 and 2 over a period of 1 second:

                   hue="H=2*PI*t: s=sin(2*PI*t)+1"

       ·   Apply a 3 seconds saturation fade-in effect starting at 0:

                   hue="s=min(t/3\,1)"

           The general fade-in expression can be written as:

                   hue="s=min(0\, max((t-START)/DURATION\, 1))"

       ·   Apply a 3 seconds saturation fade-out effect starting at 5 seconds:

                   hue="s=max(0\, min(1\, (8-t)/3))"

           The general fade-out expression can be written as:

                   hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"

       Commands

       This filter supports the following commands:

       b
       s
       h
       H   Modify the hue and/or the saturation and/or brightness of the input video.  The
           command accepts the same syntax of the corresponding option.

           If the specified expression is not valid, it is kept at its current value.

   hysteresis
       Grow first stream into second stream by connecting components.  This makes it possible to
       build more robust edge masks.

       This filter accepts the following options:

       planes
           Set which planes will be processed as bitmap, unprocessed planes will be copied from
           first stream.  By default value 0xf, all planes will be processed.

       threshold
           Set threshold which is used in filtering. If pixel component value is higher than this
           value filter algorithm for connecting components is activated.  By default value is 0.

   idet
       Detect video interlacing type.

       This filter tries to detect if the input frames are interlaced, progressive, top or bottom
       field first. It will also try to detect fields that are repeated between adjacent frames
       (a sign of telecine).

       Single frame detection considers only immediately adjacent frames when classifying each
       frame.  Multiple frame detection incorporates the classification history of previous
       frames.

       The filter will log these metadata values:

       single.current_frame
           Detected type of current frame using single-frame detection. One of: ``tff'' (top
           field first), ``bff'' (bottom field first), ``progressive'', or ``undetermined''

       single.tff
           Cumulative number of frames detected as top field first using single-frame detection.

       multiple.tff
           Cumulative number of frames detected as top field first using multiple-frame
           detection.

       single.bff
           Cumulative number of frames detected as bottom field first using single-frame
           detection.

       multiple.current_frame
           Detected type of current frame using multiple-frame detection. One of: ``tff'' (top
           field first), ``bff'' (bottom field first), ``progressive'', or ``undetermined''

       multiple.bff
           Cumulative number of frames detected as bottom field first using multiple-frame
           detection.

       single.progressive
           Cumulative number of frames detected as progressive using single-frame detection.

       multiple.progressive
           Cumulative number of frames detected as progressive using multiple-frame detection.

       single.undetermined
           Cumulative number of frames that could not be classified using single-frame detection.

       multiple.undetermined
           Cumulative number of frames that could not be classified using multiple-frame
           detection.

       repeated.current_frame
           Which field in the current frame is repeated from the last. One of ``neither'',
           ``top'', or ``bottom''.

       repeated.neither
           Cumulative number of frames with no repeated field.

       repeated.top
           Cumulative number of frames with the top field repeated from the previous frame's top
           field.

       repeated.bottom
           Cumulative number of frames with the bottom field repeated from the previous frame's
           bottom field.

       The filter accepts the following options:

       intl_thres
           Set interlacing threshold.

       prog_thres
           Set progressive threshold.

       rep_thres
           Threshold for repeated field detection.

       half_life
           Number of frames after which a given frame's contribution to the statistics is halved
           (i.e., it contributes only 0.5 to its classification). The default of 0 means that all
           frames seen are given full weight of 1.0 forever.

       analyze_interlaced_flag
           When this is not 0 then idet will use the specified number of frames to determine if
           the interlaced flag is accurate, it will not count undetermined frames.  If the flag
           is found to be accurate it will be used without any further computations, if it is
           found to be inaccurate it will be cleared without any further computations. This
           allows inserting the idet filter as a low computational method to clean up the
           interlaced flag

   il
       Deinterleave or interleave fields.

       This filter allows one to process interlaced images fields without deinterlacing them.
       Deinterleaving splits the input frame into 2 fields (so called half pictures). Odd lines
       are moved to the top half of the output image, even lines to the bottom half.  You can
       process (filter) them independently and then re-interleave them.

       The filter accepts the following options:

       luma_mode, l
       chroma_mode, c
       alpha_mode, a
           Available values for luma_mode, chroma_mode and alpha_mode are:

           none
               Do nothing.

           deinterleave, d
               Deinterleave fields, placing one above the other.

           interleave, i
               Interleave fields. Reverse the effect of deinterleaving.

           Default value is "none".

       luma_swap, ls
       chroma_swap, cs
       alpha_swap, as
           Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is 0.

   inflate
       Apply inflate effect to the video.

       This filter replaces the pixel by the local(3x3) average by taking into account only
       values higher than the pixel.

       It accepts the following options:

       threshold0
       threshold1
       threshold2
       threshold3
           Limit the maximum change for each plane, default is 65535.  If 0, plane will remain
           unchanged.

   interlace
       Simple interlacing filter from progressive contents. This interleaves upper (or lower)
       lines from odd frames with lower (or upper) lines from even frames, halving the frame rate
       and preserving image height.

                  Original        Original             New Frame
                  Frame 'j'      Frame 'j+1'             (tff)
                 ==========      ===========       ==================
                   Line 0  -------------------->    Frame 'j' Line 0
                   Line 1          Line 1  ---->   Frame 'j+1' Line 1
                   Line 2 --------------------->    Frame 'j' Line 2
                   Line 3          Line 3  ---->   Frame 'j+1' Line 3
                    ...             ...                   ...
               New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on

       It accepts the following optional parameters:

       scan
           This determines whether the interlaced frame is taken from the even (tff - default) or
           odd (bff) lines of the progressive frame.

       lowpass
           Enable (default) or disable the vertical lowpass filter to avoid twitter interlacing
           and reduce moire patterns.

   kerndeint
       Deinterlace input video by applying Donald Graft's adaptive kernel deinterling. Work on
       interlaced parts of a video to produce progressive frames.

       The description of the accepted parameters follows.

       thresh
           Set the threshold which affects the filter's tolerance when determining if a pixel
           line must be processed. It must be an integer in the range [0,255] and defaults to 10.
           A value of 0 will result in applying the process on every pixels.

       map Paint pixels exceeding the threshold value to white if set to 1.  Default is 0.

       order
           Set the fields order. Swap fields if set to 1, leave fields alone if 0. Default is 0.

       sharp
           Enable additional sharpening if set to 1. Default is 0.

       twoway
           Enable twoway sharpening if set to 1. Default is 0.

       Examples

       ·   Apply default values:

                   kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0

       ·   Enable additional sharpening:

                   kerndeint=sharp=1

       ·   Paint processed pixels in white:

                   kerndeint=map=1

   lenscorrection
       Correct radial lens distortion

       This filter can be used to correct for radial distortion as can result from the use of
       wide angle lenses, and thereby re-rectify the image. To find the right parameters one can
       use tools available for example as part of opencv or simply trial-and-error.  To use
       opencv use the calibration sample (under samples/cpp) from the opencv sources and extract
       the k1 and k2 coefficients from the resulting matrix.

       Note that effectively the same filter is available in the open-source tools Krita and
       Digikam from the KDE project.

       In contrast to the vignette filter, which can also be used to compensate lens errors, this
       filter corrects the distortion of the image, whereas vignette corrects the brightness
       distribution, so you may want to use both filters together in certain cases, though you
       will have to take care of ordering, i.e. whether vignetting should be applied before or
       after lens correction.

       Options

       The filter accepts the following options:

       cx  Relative x-coordinate of the focal point of the image, and thereby the center of the
           distortion. This value has a range [0,1] and is expressed as fractions of the image
           width.

       cy  Relative y-coordinate of the focal point of the image, and thereby the center of the
           distortion. This value has a range [0,1] and is expressed as fractions of the image
           height.

       k1  Coefficient of the quadratic correction term. 0.5 means no correction.

       k2  Coefficient of the double quadratic correction term. 0.5 means no correction.

       The formula that generates the correction is:

       r_src = r_tgt * (1 + k1 * (r_tgt / r_0)^2 + k2 * (r_tgt / r_0)^4)

       where r_0 is halve of the image diagonal and r_src and r_tgt are the distances from the
       focal point in the source and target images, respectively.

   loop
       Loop video frames.

       The filter accepts the following options:

       loop
           Set the number of loops.

       size
           Set maximal size in number of frames.

       start
           Set first frame of loop.

   lut3d
       Apply a 3D LUT to an input video.

       The filter accepts the following options:

       file
           Set the 3D LUT file name.

           Currently supported formats:

           3dl AfterEffects

           cube
               Iridas

           dat DaVinci

           m3d Pandora

       interp
           Select interpolation mode.

           Available values are:

           nearest
               Use values from the nearest defined point.

           trilinear
               Interpolate values using the 8 points defining a cube.

           tetrahedral
               Interpolate values using a tetrahedron.

   lut, lutrgb, lutyuv
       Compute a look-up table for binding each pixel component input value to an output value,
       and apply it to the input video.

       lutyuv applies a lookup table to a YUV input video, lutrgb to an RGB input video.

       These filters accept the following parameters:

       c0  set first pixel component expression

       c1  set second pixel component expression

       c2  set third pixel component expression

       c3  set fourth pixel component expression, corresponds to the alpha component

       r   set red component expression

       g   set green component expression

       b   set blue component expression

       a   alpha component expression

       y   set Y/luminance component expression

       u   set U/Cb component expression

       v   set V/Cr component expression

       Each of them specifies the expression to use for computing the lookup table for the
       corresponding pixel component values.

       The exact component associated to each of the c* options depends on the format in input.

       The lut filter requires either YUV or RGB pixel formats in input, lutrgb requires RGB
       pixel formats in input, and lutyuv requires YUV.

       The expressions can contain the following constants and functions:

       w
       h   The input width and height.

       val The input value for the pixel component.

       clipval
           The input value, clipped to the minval-maxval range.

       maxval
           The maximum value for the pixel component.

       minval
           The minimum value for the pixel component.

       negval
           The negated value for the pixel component value, clipped to the minval-maxval range;
           it corresponds to the expression "maxval-clipval+minval".

       clip(val)
           The computed value in val, clipped to the minval-maxval range.

       gammaval(gamma)
           The computed gamma correction value of the pixel component value, clipped to the
           minval-maxval range. It corresponds to the expression
           "pow((clipval-minval)/(maxval-minval)\,gamma)*(maxval-minval)+minval"

       All expressions default to "val".

       Examples

       ·   Negate input video:

                   lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
                   lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"

           The above is the same as:

                   lutrgb="r=negval:g=negval:b=negval"
                   lutyuv="y=negval:u=negval:v=negval"

       ·   Negate luminance:

                   lutyuv=y=negval

       ·   Remove chroma components, turning the video into a graytone image:

                   lutyuv="u=128:v=128"

       ·   Apply a luma burning effect:

                   lutyuv="y=2*val"

       ·   Remove green and blue components:

                   lutrgb="g=0:b=0"

       ·   Set a constant alpha channel value on input:

                   format=rgba,lutrgb=a="maxval-minval/2"

       ·   Correct luminance gamma by a factor of 0.5:

                   lutyuv=y=gammaval(0.5)

       ·   Discard least significant bits of luma:

                   lutyuv=y='bitand(val, 128+64+32)'

       ·   Technicolor like effect:

                   lutyuv=u='(val-maxval/2)*2+maxval/2':v='(val-maxval/2)*2+maxval/2'

   lut2
       Compute and apply a lookup table from two video inputs.

       This filter accepts the following parameters:

       c0  set first pixel component expression

       c1  set second pixel component expression

       c2  set third pixel component expression

       c3  set fourth pixel component expression, corresponds to the alpha component

       Each of them specifies the expression to use for computing the lookup table for the
       corresponding pixel component values.

       The exact component associated to each of the c* options depends on the format in inputs.

       The expressions can contain the following constants:

       w
       h   The input width and height.

       x   The first input value for the pixel component.

       y   The second input value for the pixel component.

       bdx The first input video bit depth.

       bdy The second input video bit depth.

       All expressions default to "x".

       Examples

       ·   Highlight differences between two RGB video streams:

                   lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1)'

       ·   Highlight differences between two YUV video streams:

                   lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1)'

   maskedclamp
       Clamp the first input stream with the second input and third input stream.

       Returns the value of first stream to be between second input stream - "undershoot" and
       third input stream + "overshoot".

       This filter accepts the following options:

       undershoot
           Default value is 0.

       overshoot
           Default value is 0.

       planes
           Set which planes will be processed as bitmap, unprocessed planes will be copied from
           first stream.  By default value 0xf, all planes will be processed.

   maskedmerge
       Merge the first input stream with the second input stream using per pixel weights in the
       third input stream.

       A value of 0 in the third stream pixel component means that pixel component from first
       stream is returned unchanged, while maximum value (eg. 255 for 8-bit videos) means that
       pixel component from second stream is returned unchanged. Intermediate values define the
       amount of merging between both input stream's pixel components.

       This filter accepts the following options:

       planes
           Set which planes will be processed as bitmap, unprocessed planes will be copied from
           first stream.  By default value 0xf, all planes will be processed.

   mcdeint
       Apply motion-compensation deinterlacing.

       It needs one field per frame as input and must thus be used together with yadif=1/3 or
       equivalent.

       This filter accepts the following options:

       mode
           Set the deinterlacing mode.

           It accepts one of the following values:

           fast
           medium
           slow
               use iterative motion estimation

           extra_slow
               like slow, but use multiple reference frames.

           Default value is fast.

       parity
           Set the picture field parity assumed for the input video. It must be one of the
           following values:

           0, tff
               assume top field first

           1, bff
               assume bottom field first

           Default value is bff.

       qp  Set per-block quantization parameter (QP) used by the internal encoder.

           Higher values should result in a smoother motion vector field but less optimal
           individual vectors. Default value is 1.

   mergeplanes
       Merge color channel components from several video streams.

       The filter accepts up to 4 input streams, and merge selected input planes to the output
       video.

       This filter accepts the following options:

       mapping
           Set input to output plane mapping. Default is 0.

           The mappings is specified as a bitmap. It should be specified as a hexadecimal number
           in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the mapping for the first plane of the
           output stream. 'A' sets the number of the input stream to use (from 0 to 3), and 'a'
           the plane number of the corresponding input to use (from 0 to 3). The rest of the
           mappings is similar, 'Bb' describes the mapping for the output stream second plane,
           'Cc' describes the mapping for the output stream third plane and 'Dd' describes the
           mapping for the output stream fourth plane.

       format
           Set output pixel format. Default is "yuva444p".

       Examples

       ·   Merge three gray video streams of same width and height into single video stream:

                   [a0][a1][a2]mergeplanes=0x001020:yuv444p

       ·   Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:

                   [a0][a1]mergeplanes=0x00010210:yuva444p

       ·   Swap Y and A plane in yuva444p stream:

                   format=yuva444p,mergeplanes=0x03010200:yuva444p

       ·   Swap U and V plane in yuv420p stream:

                   format=yuv420p,mergeplanes=0x000201:yuv420p

       ·   Cast a rgb24 clip to yuv444p:

                   format=rgb24,mergeplanes=0x000102:yuv444p

   mestimate
       Estimate and export motion vectors using block matching algorithms.  Motion vectors are
       stored in frame side data to be used by other filters.

       This filter accepts the following options:

       method
           Specify the motion estimation method. Accepts one of the following values:

           esa Exhaustive search algorithm.

           tss Three step search algorithm.

           tdls
               Two dimensional logarithmic search algorithm.

           ntss
               New three step search algorithm.

           fss Four step search algorithm.

           ds  Diamond search algorithm.

           hexbs
               Hexagon-based search algorithm.

           epzs
               Enhanced predictive zonal search algorithm.

           umh Uneven multi-hexagon search algorithm.

           Default value is esa.

       mb_size
           Macroblock size. Default 16.

       search_param
           Search parameter. Default 7.

   midequalizer
       Apply Midway Image Equalization effect using two video streams.

       Midway Image Equalization adjusts a pair of images to have the same histogram, while
       maintaining their dynamics as much as possible. It's useful for e.g. matching exposures
       from a pair of stereo cameras.

       This filter has two inputs and one output, which must be of same pixel format, but may be
       of different sizes. The output of filter is first input adjusted with midway histogram of
       both inputs.

       This filter accepts the following option:

       planes
           Set which planes to process. Default is 15, which is all available planes.

   minterpolate
       Convert the video to specified frame rate using motion interpolation.

       This filter accepts the following options:

       fps Specify the output frame rate. This can be rational e.g. "60000/1001". Frames are
           dropped if fps is lower than source fps. Default 60.

       mi_mode
           Motion interpolation mode. Following values are accepted:

           dup Duplicate previous or next frame for interpolating new ones.

           blend
               Blend source frames. Interpolated frame is mean of previous and next frames.

           mci Motion compensated interpolation. Following options are effective when this mode
               is selected:

               mc_mode
                   Motion compensation mode. Following values are accepted:

                   obmc
                       Overlapped block motion compensation.

                   aobmc
                       Adaptive overlapped block motion compensation. Window weighting
                       coefficients are controlled adaptively according to the reliabilities of
                       the neighboring motion vectors to reduce oversmoothing.

                   Default mode is obmc.

               me_mode
                   Motion estimation mode. Following values are accepted:

                   bidir
                       Bidirectional motion estimation. Motion vectors are estimated for each
                       source frame in both forward and backward directions.

                   bilat
                       Bilateral motion estimation. Motion vectors are estimated directly for
                       interpolated frame.

                   Default mode is bilat.

               me  The algorithm to be used for motion estimation. Following values are accepted:

                   esa Exhaustive search algorithm.

                   tss Three step search algorithm.

                   tdls
                       Two dimensional logarithmic search algorithm.

                   ntss
                       New three step search algorithm.

                   fss Four step search algorithm.

                   ds  Diamond search algorithm.

                   hexbs
                       Hexagon-based search algorithm.

                   epzs
                       Enhanced predictive zonal search algorithm.

                   umh Uneven multi-hexagon search algorithm.

                   Default algorithm is epzs.

               mb_size
                   Macroblock size. Default 16.

               search_param
                   Motion estimation search parameter. Default 32.

               vsbmc
                   Enable variable-size block motion compensation. Motion estimation is applied
                   with smaller block sizes at object boundaries in order to make the them less
                   blur. Default is 0 (disabled).

       scd Scene change detection method. Scene change leads motion vectors to be in random
           direction. Scene change detection replace interpolated frames by duplicate ones. May
           not be needed for other modes. Following values are accepted:

           none
               Disable scene change detection.

           fdiff
               Frame difference. Corresponding pixel values are compared and if it satisfies
               scd_threshold scene change is detected.

           Default method is fdiff.

       scd_threshold
           Scene change detection threshold. Default is 5.0.

   mpdecimate
       Drop frames that do not differ greatly from the previous frame in order to reduce frame
       rate.

       The main use of this filter is for very-low-bitrate encoding (e.g. streaming over dialup
       modem), but it could in theory be used for fixing movies that were inverse-telecined
       incorrectly.

       A description of the accepted options follows.

       max Set the maximum number of consecutive frames which can be dropped (if positive), or
           the minimum interval between dropped frames (if negative). If the value is 0, the
           frame is dropped unregarding the number of previous sequentially dropped frames.

           Default value is 0.

       hi
       lo
       frac
           Set the dropping threshold values.

           Values for hi and lo are for 8x8 pixel blocks and represent actual pixel value
           differences, so a threshold of 64 corresponds to 1 unit of difference for each pixel,
           or the same spread out differently over the block.

           A frame is a candidate for dropping if no 8x8 blocks differ by more than a threshold
           of hi, and if no more than frac blocks (1 meaning the whole image) differ by more than
           a threshold of lo.

           Default value for hi is 64*12, default value for lo is 64*5, and default value for
           frac is 0.33.

   negate
       Negate input video.

       It accepts an integer in input; if non-zero it negates the alpha component (if available).
       The default value in input is 0.

   nlmeans
       Denoise frames using Non-Local Means algorithm.

       Each pixel is adjusted by looking for other pixels with similar contexts. This context
       similarity is defined by comparing their surrounding patches of size pxp. Patches are
       searched in an area of rxr around the pixel.

       Note that the research area defines centers for patches, which means some patches will be
       made of pixels outside that research area.

       The filter accepts the following options.

       s   Set denoising strength.

       p   Set patch size.

       pc  Same as p but for chroma planes.

           The default value is 0 and means automatic.

       r   Set research size.

       rc  Same as r but for chroma planes.

           The default value is 0 and means automatic.

   nnedi
       Deinterlace video using neural network edge directed interpolation.

       This filter accepts the following options:

       weights
           Mandatory option, without binary file filter can not work.  Currently file can be
           found here:
           https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin

       deint
           Set which frames to deinterlace, by default it is "all".  Can be "all" or
           "interlaced".

       field
           Set mode of operation.

           Can be one of the following:

           af  Use frame flags, both fields.

           a   Use frame flags, single field.

           t   Use top field only.

           b   Use bottom field only.

           tf  Use both fields, top first.

           bf  Use both fields, bottom first.

       planes
           Set which planes to process, by default filter process all frames.

       nsize
           Set size of local neighborhood around each pixel, used by the predictor neural
           network.

           Can be one of the following:

           s8x6
           s16x6
           s32x6
           s48x6
           s8x4
           s16x4
           s32x4
       nns Set the number of neurons in predicctor neural network.  Can be one of the following:

           n16
           n32
           n64
           n128
           n256
       qual
           Controls the number of different neural network predictions that are blended together
           to compute the final output value. Can be "fast", default or "slow".

       etype
           Set which set of weights to use in the predictor.  Can be one of the following:

           a   weights trained to minimize absolute error

           s   weights trained to minimize squared error

       pscrn
           Controls whether or not the prescreener neural network is used to decide which pixels
           should be processed by the predictor neural network and which can be handled by simple
           cubic interpolation.  The prescreener is trained to know whether cubic interpolation
           will be sufficient for a pixel or whether it should be predicted by the predictor nn.
           The computational complexity of the prescreener nn is much less than that of the
           predictor nn. Since most pixels can be handled by cubic interpolation, using the
           prescreener generally results in much faster processing.  The prescreener is pretty
           accurate, so the difference between using it and not using it is almost always
           unnoticeable.

           Can be one of the following:

           none
           original
           new

           Default is "new".

       fapprox
           Set various debugging flags.

   noformat
       Force libavfilter not to use any of the specified pixel formats for the input to the next
       filter.

       It accepts the following parameters:

       pix_fmts
           A '|'-separated list of pixel format names, such as apix_fmts=yuv420p|monow|rgb24".

       Examples

       ·   Force libavfilter to use a format different from yuv420p for the input to the vflip
           filter:

                   noformat=pix_fmts=yuv420p,vflip

       ·   Convert the input video to any of the formats not contained in the list:

                   noformat=yuv420p|yuv444p|yuv410p

   noise
       Add noise on video input frame.

       The filter accepts the following options:

       all_seed
       c0_seed
       c1_seed
       c2_seed
       c3_seed
           Set noise seed for specific pixel component or all pixel components in case of
           all_seed. Default value is 123457.

       all_strength, alls
       c0_strength, c0s
       c1_strength, c1s
       c2_strength, c2s
       c3_strength, c3s
           Set noise strength for specific pixel component or all pixel components in case
           all_strength. Default value is 0. Allowed range is [0, 100].

       all_flags, allf
       c0_flags, c0f
       c1_flags, c1f
       c2_flags, c2f
       c3_flags, c3f
           Set pixel component flags or set flags for all components if all_flags.  Available
           values for component flags are:

           a   averaged temporal noise (smoother)

           p   mix random noise with a (semi)regular pattern

           t   temporal noise (noise pattern changes between frames)

           u   uniform noise (gaussian otherwise)

       Examples

       Add temporal and uniform noise to input video:

               noise=alls=20:allf=t+u

   null
       Pass the video source unchanged to the output.

   ocr
       Optical Character Recognition

       This filter uses Tesseract for optical character recognition.

       It accepts the following options:

       datapath
           Set datapath to tesseract data. Default is to use whatever was set at installation.

       language
           Set language, default is "eng".

       whitelist
           Set character whitelist.

       blacklist
           Set character blacklist.

       The filter exports recognized text as the frame metadata "lavfi.ocr.text".

   ocv
       Apply a video transform using libopencv.

       To enable this filter, install the libopencv library and headers and configure FFmpeg with
       "--enable-libopencv".

       It accepts the following parameters:

       filter_name
           The name of the libopencv filter to apply.

       filter_params
           The parameters to pass to the libopencv filter. If not specified, the default values
           are assumed.

       Refer to the official libopencv documentation for more precise information:
       <http://docs.opencv.org/master/modules/imgproc/doc/filtering.html>

       Several libopencv filters are supported; see the following subsections.

       dilate

       Dilate an image by using a specific structuring element.  It corresponds to the libopencv
       function "cvDilate".

       It accepts the parameters: struct_el|nb_iterations.

       struct_el represents a structuring element, and has the syntax:
       colsxrows+anchor_xxanchor_y/shape

       cols and rows represent the number of columns and rows of the structuring element,
       anchor_x and anchor_y the anchor point, and shape the shape for the structuring element.
       shape must be "rect", "cross", "ellipse", or "custom".

       If the value for shape is "custom", it must be followed by a string of the form
       "=filename". The file with name filename is assumed to represent a binary image, with each
       printable character corresponding to a bright pixel. When a custom shape is used, cols and
       rows are ignored, the number or columns and rows of the read file are assumed instead.

       The default value for struct_el is "3x3+0x0/rect".

       nb_iterations specifies the number of times the transform is applied to the image, and
       defaults to 1.

       Some examples:

               # Use the default values
               ocv=dilate

               # Dilate using a structuring element with a 5x5 cross, iterating two times
               ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2

               # Read the shape from the file diamond.shape, iterating two times.
               # The file diamond.shape may contain a pattern of characters like this
               #   *
               #  ***
               # *****
               #  ***
               #   *
               # The specified columns and rows are ignored
               # but the anchor point coordinates are not
               ocv=dilate:0x0+2x2/custom=diamond.shape|2

       erode

       Erode an image by using a specific structuring element.  It corresponds to the libopencv
       function "cvErode".

       It accepts the parameters: struct_el:nb_iterations, with the same syntax and semantics as
       the dilate filter.

       smooth

       Smooth the input video.

       The filter takes the following parameters: type|param1|param2|param3|param4.

       type is the type of smooth filter to apply, and must be one of the following values:
       "blur", "blur_no_scale", "median", "gaussian", or "bilateral". The default value is
       "gaussian".

       The meaning of param1, param2, param3, and param4 depend on the smooth type. param1 and
       param2 accept integer positive values or 0. param3 and param4 accept floating point
       values.

       The default value for param1 is 3. The default value for the other parameters is 0.

       These parameters correspond to the parameters assigned to the libopencv function
       "cvSmooth".

   overlay
       Overlay one video on top of another.

       It takes two inputs and has one output. The first input is the "main" video on which the
       second input is overlaid.

       It accepts the following parameters:

       A description of the accepted options follows.

       x
       y   Set the expression for the x and y coordinates of the overlaid video on the main
           video. Default value is "0" for both expressions. In case the expression is invalid,
           it is set to a huge value (meaning that the overlay will not be displayed within the
           output visible area).

       eof_action
           The action to take when EOF is encountered on the secondary input; it accepts one of
           the following values:

           repeat
               Repeat the last frame (the default).

           endall
               End both streams.

           pass
               Pass the main input through.

       eval
           Set when the expressions for x, and y are evaluated.

           It accepts the following values:

           init
               only evaluate expressions once during the filter initialization or when a command
               is processed

           frame
               evaluate expressions for each incoming frame

           Default value is frame.

       shortest
           If set to 1, force the output to terminate when the shortest input terminates. Default
           value is 0.

       format
           Set the format for the output video.

           It accepts the following values:

           yuv420
               force YUV420 output

           yuv422
               force YUV422 output

           yuv444
               force YUV444 output

           rgb force packed RGB output

           gbrp
               force planar RGB output

           Default value is yuv420.

       rgb (deprecated)
           If set to 1, force the filter to accept inputs in the RGB color space. Default value
           is 0. This option is deprecated, use format instead.

       repeatlast
           If set to 1, force the filter to draw the last overlay frame over the main input until
           the end of the stream. A value of 0 disables this behavior. Default value is 1.

       The x, and y expressions can contain the following parameters.

       main_w, W
       main_h, H
           The main input width and height.

       overlay_w, w
       overlay_h, h
           The overlay input width and height.

       x
       y   The computed values for x and y. They are evaluated for each new frame.

       hsub
       vsub
           horizontal and vertical chroma subsample values of the output format. For example for
           the pixel format "yuv422p" hsub is 2 and vsub is 1.

       n   the number of input frame, starting from 0

       pos the position in the file of the input frame, NAN if unknown

       t   The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.

       Note that the n, pos, t variables are available only when evaluation is done per frame,
       and will evaluate to NAN when eval is set to init.

       Be aware that frames are taken from each input video in timestamp order, hence, if their
       initial timestamps differ, it is a good idea to pass the two inputs through a
       setpts=PTS-STARTPTS filter to have them begin in the same zero timestamp, as the example
       for the movie filter does.

       You can chain together more overlays but you should test the efficiency of such approach.

       Commands

       This filter supports the following commands:

       x
       y   Modify the x and y of the overlay input.  The command accepts the same syntax of the
           corresponding option.

           If the specified expression is not valid, it is kept at its current value.

       Examples

       ·   Draw the overlay at 10 pixels from the bottom right corner of the main video:

                   overlay=main_w-overlay_w-10:main_h-overlay_h-10

           Using named options the example above becomes:

                   overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10

       ·   Insert a transparent PNG logo in the bottom left corner of the input, using the ffmpeg
           tool with the "-filter_complex" option:

                   ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output

       ·   Insert 2 different transparent PNG logos (second logo on bottom right corner) using
           the ffmpeg tool:

                   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

       ·   Add a transparent color layer on top of the main video; "WxH" must specify the size of
           the main input to the overlay filter:

                   color=color=red@.3:size=WxH [over]; [in][over] overlay [out]

       ·   Play an original video and a filtered version (here with the deshake filter) side by
           side using the ffplay tool:

                   ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'

           The above command is the same as:

                   ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'

       ·   Make a sliding overlay appearing from the left to the right top part of the screen
           starting since time 2:

                   overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0

       ·   Compose output by putting two input videos side to side:

                   ffmpeg -i left.avi -i right.avi -filter_complex "
                   nullsrc=size=200x100 [background];
                   [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
                   [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
                   [background][left]       overlay=shortest=1       [background+left];
                   [background+left][right] overlay=shortest=1:x=100 [left+right]
                   "

       ·   Mask 10-20 seconds of a video by applying the delogo filter to a section

                   ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
                   -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]'
                   masked.avi

       ·   Chain several overlays in cascade:

                   nullsrc=s=200x200 [bg];
                   testsrc=s=100x100, split=4 [in0][in1][in2][in3];
                   [in0] lutrgb=r=0, [bg]   overlay=0:0     [mid0];
                   [in1] lutrgb=g=0, [mid0] overlay=100:0   [mid1];
                   [in2] lutrgb=b=0, [mid1] overlay=0:100   [mid2];
                   [in3] null,       [mid2] overlay=100:100 [out0]

   owdenoise
       Apply Overcomplete Wavelet denoiser.

       The filter accepts the following options:

       depth
           Set depth.

           Larger depth values will denoise lower frequency components more, but slow down
           filtering.

           Must be an int in the range 8-16, default is 8.

       luma_strength, ls
           Set luma strength.

           Must be a double value in the range 0-1000, default is 1.0.

       chroma_strength, cs
           Set chroma strength.

           Must be a double value in the range 0-1000, default is 1.0.

   pad
       Add paddings to the input image, and place the original input at the provided x, y
       coordinates.

       It accepts the following parameters:

       width, w
       height, h
           Specify an expression for the size of the output image with the paddings added. If the
           value for width or height is 0, the corresponding input size is used for the output.

           The width expression can reference the value set by the height expression, and vice
           versa.

           The default value of width and height is 0.

       x
       y   Specify the offsets to place the input image at within the padded area, with respect
           to the top/left border of the output image.

           The x expression can reference the value set by the y expression, and vice versa.

           The default value of x and y is 0.

       color
           Specify the color of the padded area. For the syntax of this option, check the "Color"
           section in the ffmpeg-utils manual.

           The default value of color is "black".

       eval
           Specify when to evaluate  width, height, x and y expression.

           It accepts the following values:

           init
               Only evaluate expressions once during the filter initialization or when a command
               is processed.

           frame
               Evaluate expressions for each incoming frame.

           Default value is init.

       The value for the width, height, x, and y options are expressions containing the following
       constants:

       in_w
       in_h
           The input video width and height.

       iw
       ih  These are the same as in_w and in_h.

       out_w
       out_h
           The output width and height (the size of the padded area), as specified by the width
           and height expressions.

       ow
       oh  These are the same as out_w and out_h.

       x
       y   The x and y offsets as specified by the x and y expressions, or NAN if not yet
           specified.

       a   same as iw / ih

       sar input sample aspect ratio

       dar input display aspect ratio, it is the same as (iw / ih) * sar

       hsub
       vsub
           The horizontal and vertical chroma subsample values. For example for the pixel format
           "yuv422p" hsub is 2 and vsub is 1.

       Examples

       ·   Add paddings with the color "violet" to the input video. The output video size is
           640x480, and the top-left corner of the input video is placed at column 0, row 40

                   pad=640:480:0:40:violet

           The example above is equivalent to the following command:

                   pad=width=640:height=480:x=0:y=40:color=violet

       ·   Pad the input to get an output with dimensions increased by 3/2, and put the input
           video at the center of the padded area:

                   pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"

       ·   Pad the input to get a squared output with size equal to the maximum value between the
           input width and height, and put the input video at the center of the padded area:

                   pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"

       ·   Pad the input to get a final w/h ratio of 16:9:

                   pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"

       ·   In case of anamorphic video, in order to set the output display aspect correctly, it
           is necessary to use sar in the expression, according to the relation:

                   (ih * X / ih) * sar = output_dar
                   X = output_dar / sar

           Thus the previous example needs to be modified to:

                   pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"

       ·   Double the output size and put the input video in the bottom-right corner of the
           output padded area:

                   pad="2*iw:2*ih:ow-iw:oh-ih"

   palettegen
       Generate one palette for a whole video stream.

       It accepts the following options:

       max_colors
           Set the maximum number of colors to quantize in the palette.  Note: the palette will
           still contain 256 colors; the unused palette entries will be black.

       reserve_transparent
           Create a palette of 255 colors maximum and reserve the last one for transparency.
           Reserving the transparency color is useful for GIF optimization.  If not set, the
           maximum of colors in the palette will be 256. You probably want to disable this option
           for a standalone image.  Set by default.

       stats_mode
           Set statistics mode.

           It accepts the following values:

           full
               Compute full frame histograms.

           diff
               Compute histograms only for the part that differs from previous frame. This might
               be relevant to give more importance to the moving part of your input if the
               background is static.

           single
               Compute new histogram for each frame.

           Default value is full.

       The filter also exports the frame metadata "lavfi.color_quant_ratio" ("nb_color_in /
       nb_color_out") which you can use to evaluate the degree of color quantization of the
       palette. This information is also visible at info logging level.

       Examples

       ·   Generate a representative palette of a given video using ffmpeg:

                   ffmpeg -i input.mkv -vf palettegen palette.png

   paletteuse
       Use a palette to downsample an input video stream.

       The filter takes two inputs: one video stream and a palette. The palette must be a 256
       pixels image.

       It accepts the following options:

       dither
           Select dithering mode. Available algorithms are:

           bayer
               Ordered 8x8 bayer dithering (deterministic)

           heckbert
               Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).  Note:
               this dithering is sometimes considered "wrong" and is included as a reference.

           floyd_steinberg
               Floyd and Steingberg dithering (error diffusion)

           sierra2
               Frankie Sierra dithering v2 (error diffusion)

           sierra2_4a
               Frankie Sierra dithering v2 "Lite" (error diffusion)

           Default is sierra2_4a.

       bayer_scale
           When bayer dithering is selected, this option defines the scale of the pattern (how
           much the crosshatch pattern is visible). A low value means more visible pattern for
           less banding, and higher value means less visible pattern at the cost of more banding.

           The option must be an integer value in the range [0,5]. Default is 2.

       diff_mode
           If set, define the zone to process

           rectangle
               Only the changing rectangle will be reprocessed. This is similar to GIF
               cropping/offsetting compression mechanism. This option can be useful for speed if
               only a part of the image is changing, and has use cases such as limiting the scope
               of the error diffusal dither to the rectangle that bounds the moving scene (it
               leads to more deterministic output if the scene doesn't change much, and as a
               result less moving noise and better GIF compression).

           Default is none.

       new Take new palette for each output frame.

       Examples

       ·   Use a palette (generated for example with palettegen) to encode a GIF using ffmpeg:

                   ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif

   perspective
       Correct perspective of video not recorded perpendicular to the screen.

       A description of the accepted parameters follows.

       x0
       y0
       x1
       y1
       x2
       y2
       x3
       y3  Set coordinates expression for top left, top right, bottom left and bottom right
           corners.  Default values are "0:0:W:0:0:H:W:H" with which perspective will remain
           unchanged.  If the "sense" option is set to "source", then the specified points will
           be sent to the corners of the destination. If the "sense" option is set to
           "destination", then the corners of the source will be sent to the specified
           coordinates.

           The expressions can use the following variables:

           W
           H   the width and height of video frame.

           in  Input frame count.

           on  Output frame count.

       interpolation
           Set interpolation for perspective correction.

           It accepts the following values:

           linear
           cubic

           Default value is linear.

       sense
           Set interpretation of coordinate options.

           It accepts the following values:

           0, source
               Send point in the source specified by the given coordinates to the corners of the
               destination.

           1, destination
               Send the corners of the source to the point in the destination specified by the
               given coordinates.

               Default value is source.

       eval
           Set when the expressions for coordinates x0,y0,...x3,y3 are evaluated.

           It accepts the following values:

           init
               only evaluate expressions once during the filter initialization or when a command
               is processed

           frame
               evaluate expressions for each incoming frame

           Default value is init.

   phase
       Delay interlaced video by one field time so that the field order changes.

       The intended use is to fix PAL movies that have been captured with the opposite field
       order to the film-to-video transfer.

       A description of the accepted parameters follows.

       mode
           Set phase mode.

           It accepts the following values:

           t   Capture field order top-first, transfer bottom-first.  Filter will delay the
               bottom field.

           b   Capture field order bottom-first, transfer top-first.  Filter will delay the top
               field.

           p   Capture and transfer with the same field order. This mode only exists for the
               documentation of the other options to refer to, but if you actually select it, the
               filter will faithfully do nothing.

           a   Capture field order determined automatically by field flags, transfer opposite.
               Filter selects among t and b modes on a frame by frame basis using field flags. If
               no field information is available, then this works just like u.

           u   Capture unknown or varying, transfer opposite.  Filter selects among t and b on a
               frame by frame basis by analyzing the images and selecting the alternative that
               produces best match between the fields.

           T   Capture top-first, transfer unknown or varying.  Filter selects among t and p
               using image analysis.

           B   Capture bottom-first, transfer unknown or varying.  Filter selects among b and p
               using image analysis.

           A   Capture determined by field flags, transfer unknown or varying.  Filter selects
               among t, b and p using field flags and image analysis. If no field information is
               available, then this works just like U. This is the default mode.

           U   Both capture and transfer unknown or varying.  Filter selects among t, b and p
               using image analysis only.

   pixdesctest
       Pixel format descriptor test filter, mainly useful for internal testing. The output video
       should be equal to the input video.

       For example:

               format=monow, pixdesctest

       can be used to test the monowhite pixel format descriptor definition.

   pp
       Enable the specified chain of postprocessing subfilters using libpostproc. This library
       should be automatically selected with a GPL build ("--enable-gpl").  Subfilters must be
       separated by '/' and can be disabled by prepending a '-'.  Each subfilter and some options
       have a short and a long name that can be used interchangeably, i.e. dr/dering are the
       same.

       The filters accept the following options:

       subfilters
           Set postprocessing subfilters string.

       All subfilters share common options to determine their scope:

       a/autoq
           Honor the quality commands for this subfilter.

       c/chrom
           Do chrominance filtering, too (default).

       y/nochrom
           Do luminance filtering only (no chrominance).

       n/noluma
           Do chrominance filtering only (no luminance).

       These options can be appended after the subfilter name, separated by a '|'.

       Available subfilters are:

       hb/hdeblock[|difference[|flatness]]
           Horizontal deblocking filter

           difference
               Difference factor where higher values mean more deblocking (default: 32).

           flatness
               Flatness threshold where lower values mean more deblocking (default: 39).

       vb/vdeblock[|difference[|flatness]]
           Vertical deblocking filter

           difference
               Difference factor where higher values mean more deblocking (default: 32).

           flatness
               Flatness threshold where lower values mean more deblocking (default: 39).

       ha/hadeblock[|difference[|flatness]]
           Accurate horizontal deblocking filter

           difference
               Difference factor where higher values mean more deblocking (default: 32).

           flatness
               Flatness threshold where lower values mean more deblocking (default: 39).

       va/vadeblock[|difference[|flatness]]
           Accurate vertical deblocking filter

           difference
               Difference factor where higher values mean more deblocking (default: 32).

           flatness
               Flatness threshold where lower values mean more deblocking (default: 39).

       The horizontal and vertical deblocking filters share the difference and flatness values so
       you cannot set different horizontal and vertical thresholds.

       h1/x1hdeblock
           Experimental horizontal deblocking filter

       v1/x1vdeblock
           Experimental vertical deblocking filter

       dr/dering
           Deringing filter

       tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
           threshold1
               larger -> stronger filtering

           threshold2
               larger -> stronger filtering

           threshold3
               larger -> stronger filtering

       al/autolevels[:f/fullyrange], automatic brightness / contrast correction
           f/fullyrange
               Stretch luminance to "0-255".

       lb/linblenddeint
           Linear blend deinterlacing filter that deinterlaces the given block by filtering all
           lines with a "(1 2 1)" filter.

       li/linipoldeint
           Linear interpolating deinterlacing filter that deinterlaces the given block by
           linearly interpolating every second line.

       ci/cubicipoldeint
           Cubic interpolating deinterlacing filter deinterlaces the given block by cubically
           interpolating every second line.

       md/mediandeint
           Median deinterlacing filter that deinterlaces the given block by applying a median
           filter to every second line.

       fd/ffmpegdeint
           FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
           second line with a "(-1 4 2 4 -1)" filter.

       l5/lowpass5
           Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given block
           by filtering all lines with a "(-1 2 6 2 -1)" filter.

       fq/forceQuant[|quantizer]
           Overrides the quantizer table from the input with the constant quantizer you specify.

           quantizer
               Quantizer to use

       de/default
           Default pp filter combination ("hb|a,vb|a,dr|a")

       fa/fast
           Fast pp filter combination ("h1|a,v1|a,dr|a")

       ac  High quality pp filter combination ("ha|a|128|7,va|a,dr|a")

       Examples

       ·   Apply horizontal and vertical deblocking, deringing and automatic brightness/contrast:

                   pp=hb/vb/dr/al

       ·   Apply default filters without brightness/contrast correction:

                   pp=de/-al

       ·   Apply default filters and temporal denoiser:

                   pp=default/tmpnoise|1|2|3

       ·   Apply deblocking on luminance only, and switch vertical deblocking on or off
           automatically depending on available CPU time:

                   pp=hb|y/vb|a

   pp7
       Apply Postprocessing filter 7. It is variant of the spp filter, similar to spp = 6 with 7
       point DCT, where only the center sample is used after IDCT.

       The filter accepts the following options:

       qp  Force a constant quantization parameter. It accepts an integer in range 0 to 63. If
           not set, the filter will use the QP from the video stream (if available).

       mode
           Set thresholding mode. Available modes are:

           hard
               Set hard thresholding.

           soft
               Set soft thresholding (better de-ringing effect, but likely blurrier).

           medium
               Set medium thresholding (good results, default).

   premultiply
       Apply alpha premultiply effect to input video stream using first plane of second stream as
       alpha.

       Both streams must have same dimensions and same pixel format.

   prewitt
       Apply prewitt operator to input video stream.

       The filter accepts the following option:

       planes
           Set which planes will be processed, unprocessed planes will be copied.  By default
           value 0xf, all planes will be processed.

       scale
           Set value which will be multiplied with filtered result.

       delta
           Set value which will be added to filtered result.

   psnr
       Obtain the average, maximum and minimum PSNR (Peak Signal to Noise Ratio) between two
       input videos.

       This filter takes in input two input videos, the first input is considered the "main"
       source and is passed unchanged to the output. The second input is used as a "reference"
       video for computing the PSNR.

       Both video inputs must have the same resolution and pixel format for this filter to work
       correctly. Also it assumes that both inputs have the same number of frames, which are
       compared one by one.

       The obtained average PSNR is printed through the logging system.

       The filter stores the accumulated MSE (mean squared error) of each frame, and at the end
       of the processing it is averaged across all frames equally, and the following formula is
       applied to obtain the PSNR:

               PSNR = 10*log10(MAX^2/MSE)

       Where MAX is the average of the maximum values of each component of the image.

       The description of the accepted parameters follows.

       stats_file, f
           If specified the filter will use the named file to save the PSNR of each individual
           frame. When filename equals "-" the data is sent to standard output.

       stats_version
           Specifies which version of the stats file format to use. Details of each format are
           written below.  Default value is 1.

       stats_add_max
           Determines whether the max value is output to the stats log.  Default value is 0.
           Requires stats_version >= 2. If this is set and stats_version < 2, the filter will
           return an error.

       The file printed if stats_file is selected, contains a sequence of key/value pairs of the
       form key:value for each compared couple of frames.

       If a stats_version greater than 1 is specified, a header line precedes the list of per-
       frame-pair stats, with key value pairs following the frame format with the following
       parameters:

       psnr_log_version
           The version of the log file format. Will match stats_version.

       fields
           A comma separated list of the per-frame-pair parameters included in the log.

       A description of each shown per-frame-pair parameter follows:

       n   sequential number of the input frame, starting from 1

       mse_avg
           Mean Square Error pixel-by-pixel average difference of the compared frames, averaged
           over all the image components.

       mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
           Mean Square Error pixel-by-pixel average difference of the compared frames for the
           component specified by the suffix.

       psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
           Peak Signal to Noise ratio of the compared frames for the component specified by the
           suffix.

       max_avg, max_y, max_u, max_v
           Maximum allowed value for each channel, and average over all channels.

       For example:

               movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
               [main][ref] psnr="stats_file=stats.log" [out]

       On this example the input file being processed is compared with the reference file
       ref_movie.mpg. The PSNR of each individual frame is stored in stats.log.

   pullup
       Pulldown reversal (inverse telecine) filter, capable of handling mixed hard-telecine,
       24000/1001 fps progressive, and 30000/1001 fps progressive content.

       The pullup filter is designed to take advantage of future context in making its decisions.
       This filter is stateless in the sense that it does not lock onto a pattern to follow, but
       it instead looks forward to the following fields in order to identify matches and rebuild
       progressive frames.

       To produce content with an even framerate, insert the fps filter after pullup, use
       "fps=24000/1001" if the input frame rate is 29.97fps, "fps=24" for 30fps and the (rare)
       telecined 25fps input.

       The filter accepts the following options:

       jl
       jr
       jt
       jb  These options set the amount of "junk" to ignore at the left, right, top, and bottom
           of the image, respectively. Left and right are in units of 8 pixels, while top and
           bottom are in units of 2 lines.  The default is 8 pixels on each side.

       sb  Set the strict breaks. Setting this option to 1 will reduce the chances of filter
           generating an occasional mismatched frame, but it may also cause an excessive number
           of frames to be dropped during high motion sequences.  Conversely, setting it to -1
           will make filter match fields more easily.  This may help processing of video where
           there is slight blurring between the fields, but may also cause there to be interlaced
           frames in the output.  Default value is 0.

       mp  Set the metric plane to use. It accepts the following values:

           l   Use luma plane.

           u   Use chroma blue plane.

           v   Use chroma red plane.

           This option may be set to use chroma plane instead of the default luma plane for doing
           filter's computations. This may improve accuracy on very clean source material, but
           more likely will decrease accuracy, especially if there is chroma noise (rainbow
           effect) or any grayscale video.  The main purpose of setting mp to a chroma plane is
           to reduce CPU load and make pullup usable in realtime on slow machines.

       For best results (without duplicated frames in the output file) it is necessary to change
       the output frame rate. For example, to inverse telecine NTSC input:

               ffmpeg -i input -vf pullup -r 24000/1001 ...

   qp
       Change video quantization parameters (QP).

       The filter accepts the following option:

       qp  Set expression for quantization parameter.

       The expression is evaluated through the eval API and can contain, among others, the
       following constants:

       known
           1 if index is not 129, 0 otherwise.

       qp  Sequentional index starting from -129 to 128.

       Examples

       ·   Some equation like:

                   qp=2+2*sin(PI*qp)

   random
       Flush video frames from internal cache of frames into a random order.  No frame is
       discarded.  Inspired by frei0r nervous filter.

       frames
           Set size in number of frames of internal cache, in range from 2 to 512. Default is 30.

       seed
           Set seed for random number generator, must be an integer included between 0 and
           "UINT32_MAX". If not specified, or if explicitly set to less than 0, the filter will
           try to use a good random seed on a best effort basis.

   readeia608
       Read closed captioning (EIA-608) information from the top lines of a video frame.

       This filter adds frame metadata for "lavfi.readeia608.X.cc" and "lavfi.readeia608.X.line",
       where "X" is the number of the identified line with EIA-608 data (starting from 0). A
       description of each metadata value follows:

       lavfi.readeia608.X.cc
           The two bytes stored as EIA-608 data (printed in hexadecimal).

       lavfi.readeia608.X.line
           The number of the line on which the EIA-608 data was identified and read.

       This filter accepts the following options:

       scan_min
           Set the line to start scanning for EIA-608 data. Default is 0.

       scan_max
           Set the line to end scanning for EIA-608 data. Default is 29.

       mac Set minimal acceptable amplitude change for sync codes detection.  Default is 0.2.
           Allowed range is "[0.001 - 1]".

       spw Set the ratio of width reserved for sync code detection.  Default is 0.27. Allowed
           range is "[0.01 - 0.7]".

       mhd Set the max peaks height difference for sync code detection.  Default is 0.1. Allowed
           range is "[0.0 - 0.5]".

       mpd Set max peaks period difference for sync code detection.  Default is 0.1. Allowed
           range is "[0.0 - 0.5]".

       msd Set the first two max start code bits differences.  Default is 0.02. Allowed range is
           "[0.0 - 0.5]".

       bhd Set the minimum ratio of bits height compared to 3rd start code bit.  Default is 0.75.
           Allowed range is "[0.01 - 1]".

       th_w
           Set the white color threshold. Default is 0.35. Allowed range is "[0.1 - 1]".

       th_b
           Set the black color threshold. Default is 0.15. Allowed range is "[0.0 - 0.5]".

       chp Enable checking the parity bit. In the event of a parity error, the filter will output
           0x00 for that character. Default is false.

       Examples

       ·   Output a csv with presentation time and the first two lines of identified EIA-608
           captioning data.

                   ffprobe -f lavfi -i movie=captioned_video.mov,readeia608 -show_entries frame=pkt_pts_time:frame_tags=lavfi.readeia608.0.cc,lavfi.readeia608.1.cc -of csv

   readvitc
       Read vertical interval timecode (VITC) information from the top lines of a video frame.

       The filter adds frame metadata key "lavfi.readvitc.tc_str" with the timecode value, if a
       valid timecode has been detected. Further metadata key "lavfi.readvitc.found" is set to
       0/1 depending on whether timecode data has been found or not.

       This filter accepts the following options:

       scan_max
           Set the maximum number of lines to scan for VITC data. If the value is set to "-1" the
           full video frame is scanned. Default is 45.

       thr_b
           Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0],
           default value is 0.2. The value must be equal or less than "thr_w".

       thr_w
           Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0],
           default value is 0.6. The value must be equal or greater than "thr_b".

       Examples

       ·   Detect and draw VITC data onto the video frame; if no valid VITC is detected, draw
           "--:--:--:--" as a placeholder:

                   ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--}:x=(w-tw)/2:y=400-ascent'

   remap
       Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.

       Destination pixel at position (X, Y) will be picked from source (x, y) position where x =
       Xmap(X, Y) and y = Ymap(X, Y). If mapping values are out of range, zero value for pixel
       will be used for destination pixel.

       Xmap and Ymap input video streams must be of same dimensions. Output video stream will
       have Xmap/Ymap video stream dimensions.  Xmap and Ymap input video streams are 16bit
       depth, single channel.

   removegrain
       The removegrain filter is a spatial denoiser for progressive video.

       m0  Set mode for the first plane.

       m1  Set mode for the second plane.

       m2  Set mode for the third plane.

       m3  Set mode for the fourth plane.

       Range of mode is from 0 to 24. Description of each mode follows:

       0   Leave input plane unchanged. Default.

       1   Clips the pixel with the minimum and maximum of the 8 neighbour pixels.

       2   Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.

       3   Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.

       4   Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.  This
           is equivalent to a median filter.

       5   Line-sensitive clipping giving the minimal change.

       6   Line-sensitive clipping, intermediate.

       7   Line-sensitive clipping, intermediate.

       8   Line-sensitive clipping, intermediate.

       9   Line-sensitive clipping on a line where the neighbours pixels are the closest.

       10  Replaces the target pixel with the closest neighbour.

       11  [1 2 1] horizontal and vertical kernel blur.

       12  Same as mode 11.

       13  Bob mode, interpolates top field from the line where the neighbours pixels are the
           closest.

       14  Bob mode, interpolates bottom field from the line where the neighbours pixels are the
           closest.

       15  Bob mode, interpolates top field. Same as 13 but with a more complicated interpolation
           formula.

       16  Bob mode, interpolates bottom field. Same as 14 but with a more complicated
           interpolation formula.

       17  Clips the pixel with the minimum and maximum of respectively the maximum and minimum
           of each pair of opposite neighbour pixels.

       18  Line-sensitive clipping using opposite neighbours whose greatest distance from the
           current pixel is minimal.

       19  Replaces the pixel with the average of its 8 neighbours.

       20  Averages the 9 pixels ([1 1 1] horizontal and vertical blur).

       21  Clips pixels using the averages of opposite neighbour.

       22  Same as mode 21 but simpler and faster.

       23  Small edge and halo removal, but reputed useless.

       24  Similar as 23.

   removelogo
       Suppress a TV station logo, using an image file to determine which pixels comprise the
       logo. It works by filling in the pixels that comprise the logo with neighboring pixels.

       The filter accepts the following options:

       filename, f
           Set the filter bitmap file, which can be any image format supported by libavformat.
           The width and height of the image file must match those of the video stream being
           processed.

       Pixels in the provided bitmap image with a value of zero are not considered part of the
       logo, non-zero pixels are considered part of the logo. If you use white (255) for the logo
       and black (0) for the rest, you will be safe. For making the filter bitmap, it is
       recommended to take a screen capture of a black frame with the logo visible, and then
       using a threshold filter followed by the erode filter once or twice.

       If needed, little splotches can be fixed manually. Remember that if logo pixels are not
       covered, the filter quality will be much reduced. Marking too many pixels as part of the
       logo does not hurt as much, but it will increase the amount of blurring needed to cover
       over the image and will destroy more information than necessary, and extra pixels will
       slow things down on a large logo.

   repeatfields
       This filter uses the repeat_field flag from the Video ES headers and hard repeats fields
       based on its value.

   reverse
       Reverse a video clip.

       Warning: This filter requires memory to buffer the entire clip, so trimming is suggested.

       Examples

       ·   Take the first 5 seconds of a clip, and reverse it.

                   trim=end=5,reverse

   rotate
       Rotate video by an arbitrary angle expressed in radians.

       The filter accepts the following options:

       A description of the optional parameters follows.

       angle, a
           Set an expression for the angle by which to rotate the input video clockwise,
           expressed as a number of radians. A negative value will result in a counter-clockwise
           rotation. By default it is set to "0".

           This expression is evaluated for each frame.

       out_w, ow
           Set the output width expression, default value is "iw".  This expression is evaluated
           just once during configuration.

       out_h, oh
           Set the output height expression, default value is "ih".  This expression is evaluated
           just once during configuration.

       bilinear
           Enable bilinear interpolation if set to 1, a value of 0 disables it. Default value is
           1.

       fillcolor, c
           Set the color used to fill the output area not covered by the rotated image. For the
           general syntax of this option, check the "Color" section in the ffmpeg-utils manual.
           If the special value "none" is selected then no background is printed (useful for
           example if the background is never shown).

           Default value is "black".

       The expressions for the angle and the output size can contain the following constants and
       functions:

       n   sequential number of the input frame, starting from 0. It is always NAN before the
           first frame is filtered.

       t   time in seconds of the input frame, it is set to 0 when the filter is configured. It
           is always NAN before the first frame is filtered.

       hsub
       vsub
           horizontal and vertical chroma subsample values. For example for the pixel format
           "yuv422p" hsub is 2 and vsub is 1.

       in_w, iw
       in_h, ih
           the input video width and height

       out_w, ow
       out_h, oh
           the output width and height, that is the size of the padded area as specified by the
           width and height expressions

       rotw(a)
       roth(a)
           the minimal width/height required for completely containing the input video rotated by
           a radians.

           These are only available when computing the out_w and out_h expressions.

       Examples

       ·   Rotate the input by PI/6 radians clockwise:

                   rotate=PI/6

       ·   Rotate the input by PI/6 radians counter-clockwise:

                   rotate=-PI/6

       ·   Rotate the input by 45 degrees clockwise:

                   rotate=45*PI/180

       ·   Apply a constant rotation with period T, starting from an angle of PI/3:

                   rotate=PI/3+2*PI*t/T

       ·   Make the input video rotation oscillating with a period of T seconds and an amplitude
           of A radians:

                   rotate=A*sin(2*PI/T*t)

       ·   Rotate the video, output size is chosen so that the whole rotating input video is
           always completely contained in the output:

                   rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'

       ·   Rotate the video, reduce the output size so that no background is ever shown:

                   rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none

       Commands

       The filter supports the following commands:

       a, angle
           Set the angle expression.  The command accepts the same syntax of the corresponding
           option.

           If the specified expression is not valid, it is kept at its current value.

   sab
       Apply Shape Adaptive Blur.

       The filter accepts the following options:

       luma_radius, lr
           Set luma blur filter strength, must be a value in range 0.1-4.0, default value is 1.0.
           A greater value will result in a more blurred image, and in slower processing.

       luma_pre_filter_radius, lpfr
           Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default value is
           1.0.

       luma_strength, ls
           Set luma maximum difference between pixels to still be considered, must be a value in
           the 0.1-100.0 range, default value is 1.0.

       chroma_radius, cr
           Set chroma blur filter strength, must be a value in range -0.9-4.0. A greater value
           will result in a more blurred image, and in slower processing.

       chroma_pre_filter_radius, cpfr
           Set chroma pre-filter radius, must be a value in the -0.9-2.0 range.

       chroma_strength, cs
           Set chroma maximum difference between pixels to still be considered, must be a value
           in the -0.9-100.0 range.

       Each chroma option value, if not explicitly specified, is set to the corresponding luma
       option value.

   scale
       Scale (resize) the input video, using the libswscale library.

       The scale filter forces the output display aspect ratio to be the same of the input, by
       changing the output sample aspect ratio.

       If the input image format is different from the format requested by the next filter, the
       scale filter will convert the input to the requested format.

       Options

       The filter accepts the following options, or any of the options supported by the
       libswscale scaler.

       See the ffmpeg-scaler manual for the complete list of scaler options.

       width, w
       height, h
           Set the output video dimension expression. Default value is the input dimension.

           If the value is 0, the input width is used for the output.

           If one of the values is -1, the scale filter will use a value that maintains the
           aspect ratio of the input image, calculated from the other specified dimension. If
           both of them are -1, the input size is used

           If one of the values is -n with n > 1, the scale filter will also use a value that
           maintains the aspect ratio of the input image, calculated from the other specified
           dimension. After that it will, however, make sure that the calculated dimension is
           divisible by n and adjust the value if necessary.

           See below for the list of accepted constants for use in the dimension expression.

       eval
           Specify when to evaluate width and height expression. It accepts the following values:

           init
               Only evaluate expressions once during the filter initialization or when a command
               is processed.

           frame
               Evaluate expressions for each incoming frame.

           Default value is init.

       interl
           Set the interlacing mode. It accepts the following values:

           1   Force interlaced aware scaling.

           0   Do not apply interlaced scaling.

           -1  Select interlaced aware scaling depending on whether the source frames are flagged
               as interlaced or not.

           Default value is 0.

       flags
           Set libswscale scaling flags. See the ffmpeg-scaler manual for the complete list of
           values. If not explicitly specified the filter applies the default flags.

       param0, param1
           Set libswscale input parameters for scaling algorithms that need them. See the ffmpeg-
           scaler manual for the complete documentation. If not explicitly specified the filter
           applies empty parameters.

       size, s
           Set the video size. For the syntax of this option, check the "Video size" section in
           the ffmpeg-utils manual.

       in_color_matrix
       out_color_matrix
           Set in/output YCbCr color space type.

           This allows the autodetected value to be overridden as well as allows forcing a
           specific value used for the output and encoder.

           If not specified, the color space type depends on the pixel format.

           Possible values:

           auto
               Choose automatically.

           bt709
               Format conforming to International Telecommunication Union (ITU) Recommendation
               BT.709.

           fcc Set color space conforming to the United States Federal Communications Commission
               (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).

           bt601
               Set color space conforming to:

               ·   ITU Radiocommunication Sector (ITU-R) Recommendation BT.601

               ·   ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G

               ·   Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004

           smpte240m
               Set color space conforming to SMPTE ST 240:1999.

       in_range
       out_range
           Set in/output YCbCr sample range.

           This allows the autodetected value to be overridden as well as allows forcing a
           specific value used for the output and encoder. If not specified, the range depends on
           the pixel format. Possible values:

           auto
               Choose automatically.

           jpeg/full/pc
               Set full range (0-255 in case of 8-bit luma).

           mpeg/tv
               Set "MPEG" range (16-235 in case of 8-bit luma).

       force_original_aspect_ratio
           Enable decreasing or increasing output video width or height if necessary to keep the
           original aspect ratio. Possible values:

           disable
               Scale the video as specified and disable this feature.

           decrease
               The output video dimensions will automatically be decreased if needed.

           increase
               The output video dimensions will automatically be increased if needed.

           One useful instance of this option is that when you know a specific device's maximum
           allowed resolution, you can use this to limit the output video to that, while
           retaining the aspect ratio. For example, device A allows 1280x720 playback, and your
           video is 1920x800. Using this option (set it to decrease) and specifying 1280x720 to
           the command line makes the output 1280x533.

           Please note that this is a different thing than specifying -1 for w or h, you still
           need to specify the output resolution for this option to work.

       The values of the w and h options are expressions containing the following constants:

       in_w
       in_h
           The input width and height

       iw
       ih  These are the same as in_w and in_h.

       out_w
       out_h
           The output (scaled) width and height

       ow
       oh  These are the same as out_w and out_h

       a   The same as iw / ih

       sar input sample aspect ratio

       dar The input display aspect ratio. Calculated from "(iw / ih) * sar".

       hsub
       vsub
           horizontal and vertical input chroma subsample values. For example for the pixel
           format "yuv422p" hsub is 2 and vsub is 1.

       ohsub
       ovsub
           horizontal and vertical output chroma subsample values. For example for the pixel
           format "yuv422p" hsub is 2 and vsub is 1.

       Examples

       ·   Scale the input video to a size of 200x100

                   scale=w=200:h=100

           This is equivalent to:

                   scale=200:100

           or:

                   scale=200x100

       ·   Specify a size abbreviation for the output size:

                   scale=qcif

           which can also be written as:

                   scale=size=qcif

       ·   Scale the input to 2x:

                   scale=w=2*iw:h=2*ih

       ·   The above is the same as:

                   scale=2*in_w:2*in_h

       ·   Scale the input to 2x with forced interlaced scaling:

                   scale=2*iw:2*ih:interl=1

       ·   Scale the input to half size:

                   scale=w=iw/2:h=ih/2

       ·   Increase the width, and set the height to the same size:

                   scale=3/2*iw:ow

       ·   Seek Greek harmony:

                   scale=iw:1/PHI*iw
                   scale=ih*PHI:ih

       ·   Increase the height, and set the width to 3/2 of the height:

                   scale=w=3/2*oh:h=3/5*ih

       ·   Increase the size, making the size a multiple of the chroma subsample values:

                   scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"

       ·   Increase the width to a maximum of 500 pixels, keeping the same aspect ratio as the
           input:

                   scale=w='min(500\, iw*3/2):h=-1'

       Commands

       This filter supports the following commands:

       width, w
       height, h
           Set the output video dimension expression.  The command accepts the same syntax of the
           corresponding option.

           If the specified expression is not valid, it is kept at its current value.

   scale_npp
       Use the NVIDIA Performance Primitives (libnpp) to perform scaling and/or pixel format
       conversion on CUDA video frames. Setting the output width and height works in the same way
       as for the scale filter.

       The following additional options are accepted:

       format
           The pixel format of the output CUDA frames. If set to the string "same" (the default),
           the input format will be kept. Note that automatic format negotiation and conversion
           is not yet supported for hardware frames

       interp_algo
           The interpolation algorithm used for resizing. One of the following:

           nn  Nearest neighbour.

           linear
           cubic
           cubic2p_bspline
               2-parameter cubic (B=1, C=0)

           cubic2p_catmullrom
               2-parameter cubic (B=0, C=1/2)

           cubic2p_b05c03
               2-parameter cubic (B=1/2, C=3/10)

           super
               Supersampling

           lanczos

   scale2ref
       Scale (resize) the input video, based on a reference video.

       See the scale filter for available options, scale2ref supports the same but uses the
       reference video instead of the main input as basis.

       Examples

       ·   Scale a subtitle stream (b) to match the main video (a) in size before overlaying

                   'scale2ref[b][a];[a][b]overlay'

   selectivecolor
       Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such as "reds",
       "yellows", "greens", "cyans", ...). The adjustment range is defined by the "purity" of the
       color (that is, how saturated it already is).

       This filter is similar to the Adobe Photoshop Selective Color tool.

       The filter accepts the following options:

       correction_method
           Select color correction method.

           Available values are:

           absolute
               Specified adjustments are applied "as-is" (added/subtracted to original pixel
               component value).

           relative
               Specified adjustments are relative to the original component value.

           Default is "absolute".

       reds
           Adjustments for red pixels (pixels where the red component is the maximum)

       yellows
           Adjustments for yellow pixels (pixels where the blue component is the minimum)

       greens
           Adjustments for green pixels (pixels where the green component is the maximum)

       cyans
           Adjustments for cyan pixels (pixels where the red component is the minimum)

       blues
           Adjustments for blue pixels (pixels where the blue component is the maximum)

       magentas
           Adjustments for magenta pixels (pixels where the green component is the minimum)

       whites
           Adjustments for white pixels (pixels where all components are greater than 128)

       neutrals
           Adjustments for all pixels except pure black and pure white

       blacks
           Adjustments for black pixels (pixels where all components are lesser than 128)

       psfile
           Specify a Photoshop selective color file (".asv") to import the settings from.

       All the adjustment settings (reds, yellows, ...) accept up to 4 space separated floating
       point adjustment values in the [-1,1] range, respectively to adjust the amount of cyan,
       magenta, yellow and black for the pixels of its range.

       Examples

       ·   Increase cyan by 50% and reduce yellow by 33% in every green areas, and increase
           magenta by 27% in blue areas:

                   selectivecolor=greens=.5 0 -.33 0:blues=0 .27

       ·   Use a Photoshop selective color preset:

                   selectivecolor=psfile=MySelectiveColorPresets/Misty.asv

   separatefields
       The "separatefields" takes a frame-based video input and splits each frame into its
       components fields, producing a new half height clip with twice the frame rate and twice
       the frame count.

       This filter use field-dominance information in frame to decide which of each pair of
       fields to place first in the output.  If it gets it wrong use setfield filter before
       "separatefields" filter.

   setdar, setsar
       The "setdar" filter sets the Display Aspect Ratio for the filter output video.

       This is done by changing the specified Sample (aka Pixel) Aspect Ratio, according to the
       following equation:

               <DAR> = <HORIZONTAL_RESOLUTION> / <VERTICAL_RESOLUTION> * <SAR>

       Keep in mind that the "setdar" filter does not modify the pixel dimensions of the video
       frame. Also, the display aspect ratio set by this filter may be changed by later filters
       in the filterchain, e.g. in case of scaling or if another "setdar" or a "setsar" filter is
       applied.

       The "setsar" filter sets the Sample (aka Pixel) Aspect Ratio for the filter output video.

       Note that as a consequence of the application of this filter, the output display aspect
       ratio will change according to the equation above.

       Keep in mind that the sample aspect ratio set by the "setsar" filter may be changed by
       later filters in the filterchain, e.g. if another "setsar" or a "setdar" filter is
       applied.

       It accepts the following parameters:

       r, ratio, dar ("setdar" only), sar ("setsar" only)
           Set the aspect ratio used by the filter.

           The parameter can be a floating point number string, an expression, or a string of the
           form num:den, where num and den are the numerator and denominator of the aspect ratio.
           If the parameter is not specified, it is assumed the value "0".  In case the form
           "num:den" is used, the ":" character should be escaped.

       max Set the maximum integer value to use for expressing numerator and denominator when
           reducing the expressed aspect ratio to a rational.  Default value is 100.

       The parameter sar is an expression containing the following constants:

       E, PI, PHI
           These are approximated values for the mathematical constants e (Euler's number), pi
           (Greek pi), and phi (the golden ratio).

       w, h
           The input width and height.

       a   These are the same as w / h.

       sar The input sample aspect ratio.

       dar The input display aspect ratio. It is the same as (w / h) * sar.

       hsub, vsub
           Horizontal and vertical chroma subsample values. For example, for the pixel format
           "yuv422p" hsub is 2 and vsub is 1.

       Examples

       ·   To change the display aspect ratio to 16:9, specify one of the following:

                   setdar=dar=1.77777
                   setdar=dar=16/9

       ·   To change the sample aspect ratio to 10:11, specify:

                   setsar=sar=10/11

       ·   To set a display aspect ratio of 16:9, and specify a maximum integer value of 1000 in
           the aspect ratio reduction, use the command:

                   setdar=ratio=16/9:max=1000

   setfield
       Force field for the output video frame.

       The "setfield" filter marks the interlace type field for the output frames. It does not
       change the input frame, but only sets the corresponding property, which affects how the
       frame is treated by following filters (e.g. "fieldorder" or "yadif").

       The filter accepts the following options:

       mode
           Available values are:

           auto
               Keep the same field property.

           bff Mark the frame as bottom-field-first.

           tff Mark the frame as top-field-first.

           prog
               Mark the frame as progressive.

   showinfo
       Show a line containing various information for each input video frame.  The input video is
       not modified.

       The shown line contains a sequence of key/value pairs of the form key:value.

       The following values are shown in the output:

       n   The (sequential) number of the input frame, starting from 0.

       pts The Presentation TimeStamp of the input frame, expressed as a number of time base
           units. The time base unit depends on the filter input pad.

       pts_time
           The Presentation TimeStamp of the input frame, expressed as a number of seconds.

       pos The position of the frame in the input stream, or -1 if this information is
           unavailable and/or meaningless (for example in case of synthetic video).

       fmt The pixel format name.

       sar The sample aspect ratio of the input frame, expressed in the form num/den.

       s   The size of the input frame. For the syntax of this option, check the "Video size"
           section in the ffmpeg-utils manual.

       i   The type of interlaced mode ("P" for "progressive", "T" for top field first, "B" for
           bottom field first).

       iskey
           This is 1 if the frame is a key frame, 0 otherwise.

       type
           The picture type of the input frame ("I" for an I-frame, "P" for a P-frame, "B" for a
           B-frame, or "?" for an unknown type).  Also refer to the documentation of the
           "AVPictureType" enum and of the "av_get_picture_type_char" function defined in
           libavutil/avutil.h.

       checksum
           The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.

       plane_checksum
           The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
           expressed in the form "[c0 c1 c2 c3]".

   showpalette
       Displays the 256 colors palette of each frame. This filter is only relevant for pal8 pixel
       format frames.

       It accepts the following option:

       s   Set the size of the box used to represent one palette color entry. Default is 30 (for
           a "30x30" pixel box).

   shuffleframes
       Reorder and/or duplicate and/or drop video frames.

       It accepts the following parameters:

       mapping
           Set the destination indexes of input frames.  This is space or '|' separated list of
           indexes that maps input frames to output frames. Number of indexes also sets maximal
           value that each index may have.  '-1' index have special meaning and that is to drop
           frame.

       The first frame has the index 0. The default is to keep the input unchanged.

       Examples

       ·   Swap second and third frame of every three frames of the input:

                   ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT

       ·   Swap 10th and 1st frame of every ten frames of the input:

                   ffmpeg -i INPUT -vf "shuffleframes=9 1 2 3 4 5 6 7 8 0" OUTPUT

   shuffleplanes
       Reorder and/or duplicate video planes.

       It accepts the following parameters:

       map0
           The index of the input plane to be used as the first output plane.

       map1
           The index of the input plane to be used as the second output plane.

       map2
           The index of the input plane to be used as the third output plane.

       map3
           The index of the input plane to be used as the fourth output plane.

       The first plane has the index 0. The default is to keep the input unchanged.

       Examples

       ·   Swap the second and third planes of the input:

                   ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT

   signalstats
       Evaluate various visual metrics that assist in determining issues associated with the
       digitization of analog video media.

       By default the filter will log these metadata values:

       YMIN
           Display the minimal Y value contained within the input frame. Expressed in range of
           [0-255].

       YLOW
           Display the Y value at the 10% percentile within the input frame. Expressed in range
           of [0-255].

       YAVG
           Display the average Y value within the input frame. Expressed in range of [0-255].

       YHIGH
           Display the Y value at the 90% percentile within the input frame. Expressed in range
           of [0-255].

       YMAX
           Display the maximum Y value contained within the input frame. Expressed in range of
           [0-255].

       UMIN
           Display the minimal U value contained within the input frame. Expressed in range of
           [0-255].

       ULOW
           Display the U value at the 10% percentile within the input frame. Expressed in range
           of [0-255].

       UAVG
           Display the average U value within the input frame. Expressed in range of [0-255].

       UHIGH
           Display the U value at the 90% percentile within the input frame. Expressed in range
           of [0-255].

       UMAX
           Display the maximum U value contained within the input frame. Expressed in range of
           [0-255].

       VMIN
           Display the minimal V value contained within the input frame. Expressed in range of
           [0-255].

       VLOW
           Display the V value at the 10% percentile within the input frame. Expressed in range
           of [0-255].

       VAVG
           Display the average V value within the input frame. Expressed in range of [0-255].

       VHIGH
           Display the V value at the 90% percentile within the input frame. Expressed in range
           of [0-255].

       VMAX
           Display the maximum V value contained within the input frame. Expressed in range of
           [0-255].

       SATMIN
           Display the minimal saturation value contained within the input frame.  Expressed in
           range of [0-~181.02].

       SATLOW
           Display the saturation value at the 10% percentile within the input frame.  Expressed
           in range of [0-~181.02].

       SATAVG
           Display the average saturation value within the input frame. Expressed in range of
           [0-~181.02].

       SATHIGH
           Display the saturation value at the 90% percentile within the input frame.  Expressed
           in range of [0-~181.02].

       SATMAX
           Display the maximum saturation value contained within the input frame.  Expressed in
           range of [0-~181.02].

       HUEMED
           Display the median value for hue within the input frame. Expressed in range of
           [0-360].

       HUEAVG
           Display the average value for hue within the input frame. Expressed in range of
           [0-360].

       YDIF
           Display the average of sample value difference between all values of the Y plane in
           the current frame and corresponding values of the previous input frame.  Expressed in
           range of [0-255].

       UDIF
           Display the average of sample value difference between all values of the U plane in
           the current frame and corresponding values of the previous input frame.  Expressed in
           range of [0-255].

       VDIF
           Display the average of sample value difference between all values of the V plane in
           the current frame and corresponding values of the previous input frame.  Expressed in
           range of [0-255].

       YBITDEPTH
           Display bit depth of Y plane in current frame.  Expressed in range of [0-16].

       UBITDEPTH
           Display bit depth of U plane in current frame.  Expressed in range of [0-16].

       VBITDEPTH
           Display bit depth of V plane in current frame.  Expressed in range of [0-16].

       The filter accepts the following options:

       stat
       out stat specify an additional form of image analysis.  out output video with the
           specified type of pixel highlighted.

           Both options accept the following values:

           tout
               Identify temporal outliers pixels. A temporal outlier is a pixel unlike the
               neighboring pixels of the same field. Examples of temporal outliers include the
               results of video dropouts, head clogs, or tape tracking issues.

           vrep
               Identify vertical line repetition. Vertical line repetition includes similar rows
               of pixels within a frame. In born-digital video vertical line repetition is
               common, but this pattern is uncommon in video digitized from an analog source.
               When it occurs in video that results from the digitization of an analog source it
               can indicate concealment from a dropout compensator.

           brng
               Identify pixels that fall outside of legal broadcast range.

       color, c
           Set the highlight color for the out option. The default color is yellow.

       Examples

       ·   Output data of various video metrics:

                   ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames

       ·   Output specific data about the minimum and maximum values of the Y plane per frame:

                   ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN

       ·   Playback video while highlighting pixels that are outside of broadcast range in red.

                   ffplay example.mov -vf signalstats="out=brng:color=red"

       ·   Playback video with signalstats metadata drawn over the frame.

                   ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt

           The contents of signalstat_drawtext.txt used in the command are:

                   time %{pts:hms}
                   Y (%{metadata:lavfi.signalstats.YMIN}-%{metadata:lavfi.signalstats.YMAX})
                   U (%{metadata:lavfi.signalstats.UMIN}-%{metadata:lavfi.signalstats.UMAX})
                   V (%{metadata:lavfi.signalstats.VMIN}-%{metadata:lavfi.signalstats.VMAX})
                   saturation maximum: %{metadata:lavfi.signalstats.SATMAX}

   signature
       Calculates the MPEG-7 Video Signature. The filter can handle more than one input. In this
       case the matching between the inputs can be calculated additionally.  The filter always
       passes through the first input. The signature of each stream can be written into a file.

       It accepts the following options:

       detectmode
           Enable or disable the matching process.

           Available values are:

           off Disable the calculation of a matching (default).

           full
               Calculate the matching for the whole video and output whether the whole video
               matches or only parts.

           fast
               Calculate only until a matching is found or the video ends. Should be faster in
               some cases.

       nb_inputs
           Set the number of inputs. The option value must be a non negative integer.  Default
           value is 1.

       filename
           Set the path to which the output is written. If there is more than one input, the path
           must be a prototype, i.e. must contain %d or %0nd (where n is a positive integer),
           that will be replaced with the input number. If no filename is specified, no output
           will be written. This is the default.

       format
           Choose the output format.

           Available values are:

           binary
               Use the specified binary representation (default).

           xml Use the specified xml representation.

       th_d
           Set threshold to detect one word as similar. The option value must be an integer
           greater than zero. The default value is 9000.

       th_dc
           Set threshold to detect all words as similar. The option value must be an integer
           greater than zero. The default value is 60000.

       th_xh
           Set threshold to detect frames as similar. The option value must be an integer greater
           than zero. The default value is 116.

       th_di
           Set the minimum length of a sequence in frames to recognize it as matching sequence.
           The option value must be a non negative integer value.  The default value is 0.

       th_it
           Set the minimum relation, that matching frames to all frames must have.  The option
           value must be a double value between 0 and 1. The default value is 0.5.

       Examples

       ·   To calculate the signature of an input video and store it in signature.bin:

                   ffmpeg -i input.mkv -vf signature=filename=signature.bin -map 0:v -f null -

       ·   To detect whether two videos match and store the signatures in XML format in
           signature0.xml and signature1.xml:

                   ffmpeg -i input1.mkv -i input2.mkv -filter_complex "[0:v][1:v] signature=nb_inputs=2:detectmode=full:format=xml:filename=signature%d.xml" -map :v -f null -

   smartblur
       Blur the input video without impacting the outlines.

       It accepts the following options:

       luma_radius, lr
           Set the luma radius. The option value must be a float number in the range [0.1,5.0]
           that specifies the variance of the gaussian filter used to blur the image (slower if
           larger). Default value is 1.0.

       luma_strength, ls
           Set the luma strength. The option value must be a float number in the range [-1.0,1.0]
           that configures the blurring. A value included in [0.0,1.0] will blur the image
           whereas a value included in [-1.0,0.0] will sharpen the image. Default value is 1.0.

       luma_threshold, lt
           Set the luma threshold used as a coefficient to determine whether a pixel should be
           blurred or not. The option value must be an integer in the range [-30,30]. A value of
           0 will filter all the image, a value included in [0,30] will filter flat areas and a
           value included in [-30,0] will filter edges. Default value is 0.

       chroma_radius, cr
           Set the chroma radius. The option value must be a float number in the range [0.1,5.0]
           that specifies the variance of the gaussian filter used to blur the image (slower if
           larger). Default value is luma_radius.

       chroma_strength, cs
           Set the chroma strength. The option value must be a float number in the range
           [-1.0,1.0] that configures the blurring. A value included in [0.0,1.0] will blur the
           image whereas a value included in [-1.0,0.0] will sharpen the image. Default value is
           luma_strength.

       chroma_threshold, ct
           Set the chroma threshold used as a coefficient to determine whether a pixel should be
           blurred or not. The option value must be an integer in the range [-30,30]. A value of
           0 will filter all the image, a value included in [0,30] will filter flat areas and a
           value included in [-30,0] will filter edges. Default value is luma_threshold.

       If a chroma option is not explicitly set, the corresponding luma value is set.

   ssim
       Obtain the SSIM (Structural SImilarity Metric) between two input videos.

       This filter takes in input two input videos, the first input is considered the "main"
       source and is passed unchanged to the output. The second input is used as a "reference"
       video for computing the SSIM.

       Both video inputs must have the same resolution and pixel format for this filter to work
       correctly. Also it assumes that both inputs have the same number of frames, which are
       compared one by one.

       The filter stores the calculated SSIM of each frame.

       The description of the accepted parameters follows.

       stats_file, f
           If specified the filter will use the named file to save the SSIM of each individual
           frame. When filename equals "-" the data is sent to standard output.

       The file printed if stats_file is selected, contains a sequence of key/value pairs of the
       form key:value for each compared couple of frames.

       A description of each shown parameter follows:

       n   sequential number of the input frame, starting from 1

       Y, U, V, R, G, B
           SSIM of the compared frames for the component specified by the suffix.

       All SSIM of the compared frames for the whole frame.

       dB  Same as above but in dB representation.

       For example:

               movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
               [main][ref] ssim="stats_file=stats.log" [out]

       On this example the input file being processed is compared with the reference file
       ref_movie.mpg. The SSIM of each individual frame is stored in stats.log.

       Another example with both psnr and ssim at same time:

               ffmpeg -i main.mpg -i ref.mpg -lavfi  "ssim;[0:v][1:v]psnr" -f null -

   stereo3d
       Convert between different stereoscopic image formats.

       The filters accept the following options:

       in  Set stereoscopic image format of input.

           Available values for input image formats are:

           sbsl
               side by side parallel (left eye left, right eye right)

           sbsr
               side by side crosseye (right eye left, left eye right)

           sbs2l
               side by side parallel with half width resolution (left eye left, right eye right)

           sbs2r
               side by side crosseye with half width resolution (right eye left, left eye right)

           abl above-below (left eye above, right eye below)

           abr above-below (right eye above, left eye below)

           ab2l
               above-below with half height resolution (left eye above, right eye below)

           ab2r
               above-below with half height resolution (right eye above, left eye below)

           al  alternating frames (left eye first, right eye second)

           ar  alternating frames (right eye first, left eye second)

           irl interleaved rows (left eye has top row, right eye starts on next row)

           irr interleaved rows (right eye has top row, left eye starts on next row)

           icl interleaved columns, left eye first

           icr interleaved columns, right eye first

               Default value is sbsl.

       out Set stereoscopic image format of output.

           sbsl
               side by side parallel (left eye left, right eye right)

           sbsr
               side by side crosseye (right eye left, left eye right)

           sbs2l
               side by side parallel with half width resolution (left eye left, right eye right)

           sbs2r
               side by side crosseye with half width resolution (right eye left, left eye right)

           abl above-below (left eye above, right eye below)

           abr above-below (right eye above, left eye below)

           ab2l
               above-below with half height resolution (left eye above, right eye below)

           ab2r
               above-below with half height resolution (right eye above, left eye below)

           al  alternating frames (left eye first, right eye second)

           ar  alternating frames (right eye first, left eye second)

           irl interleaved rows (left eye has top row, right eye starts on next row)

           irr interleaved rows (right eye has top row, left eye starts on next row)

           arbg
               anaglyph red/blue gray (red filter on left eye, blue filter on right eye)

           argg
               anaglyph red/green gray (red filter on left eye, green filter on right eye)

           arcg
               anaglyph red/cyan gray (red filter on left eye, cyan filter on right eye)

           arch
               anaglyph red/cyan half colored (red filter on left eye, cyan filter on right eye)

           arcc
               anaglyph red/cyan color (red filter on left eye, cyan filter on right eye)

           arcd
               anaglyph red/cyan color optimized with the least squares projection of dubois (red
               filter on left eye, cyan filter on right eye)

           agmg
               anaglyph green/magenta gray (green filter on left eye, magenta filter on right
               eye)

           agmh
               anaglyph green/magenta half colored (green filter on left eye, magenta filter on
               right eye)

           agmc
               anaglyph green/magenta colored (green filter on left eye, magenta filter on right
               eye)

           agmd
               anaglyph green/magenta color optimized with the least squares projection of dubois
               (green filter on left eye, magenta filter on right eye)

           aybg
               anaglyph yellow/blue gray (yellow filter on left eye, blue filter on right eye)

           aybh
               anaglyph yellow/blue half colored (yellow filter on left eye, blue filter on right
               eye)

           aybc
               anaglyph yellow/blue colored (yellow filter on left eye, blue filter on right eye)

           aybd
               anaglyph yellow/blue color optimized with the least squares projection of dubois
               (yellow filter on left eye, blue filter on right eye)

           ml  mono output (left eye only)

           mr  mono output (right eye only)

           chl checkerboard, left eye first

           chr checkerboard, right eye first

           icl interleaved columns, left eye first

           icr interleaved columns, right eye first

           hdmi
               HDMI frame pack

           Default value is arcd.

       Examples

       ·   Convert input video from side by side parallel to anaglyph yellow/blue dubois:

                   stereo3d=sbsl:aybd

       ·   Convert input video from above below (left eye above, right eye below) to side by side
           crosseye.

                   stereo3d=abl:sbsr

   streamselect, astreamselect
       Select video or audio streams.

       The filter accepts the following options:

       inputs
           Set number of inputs. Default is 2.

       map Set input indexes to remap to outputs.

       Commands

       The "streamselect" and "astreamselect" filter supports the following commands:

       map Set input indexes to remap to outputs.

       Examples

       ·   Select first 5 seconds 1st stream and rest of time 2nd stream:

                   sendcmd='5.0 streamselect map 1',streamselect=inputs=2:map=0

       ·   Same as above, but for audio:

                   asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0

   sobel
       Apply sobel operator to input video stream.

       The filter accepts the following option:

       planes
           Set which planes will be processed, unprocessed planes will be copied.  By default
           value 0xf, all planes will be processed.

       scale
           Set value which will be multiplied with filtered result.

       delta
           Set value which will be added to filtered result.

   spp
       Apply a simple postprocessing filter that compresses and decompresses the image at several
       (or - in the case of quality level 6 - all) shifts and average the results.

       The filter accepts the following options:

       quality
           Set quality. This option defines the number of levels for averaging. It accepts an
           integer in the range 0-6. If set to 0, the filter will have no effect. A value of 6
           means the higher quality. For each increment of that value the speed drops by a factor
           of approximately 2.  Default value is 3.

       qp  Force a constant quantization parameter. If not set, the filter will use the QP from
           the video stream (if available).

       mode
           Set thresholding mode. Available modes are:

           hard
               Set hard thresholding (default).

           soft
               Set soft thresholding (better de-ringing effect, but likely blurrier).

       use_bframe_qp
           Enable the use of the QP from the B-Frames if set to 1. Using this option may cause
           flicker since the B-Frames have often larger QP. Default is 0 (not enabled).

   subtitles
       Draw subtitles on top of input video using the libass library.

       To enable compilation of this filter you need to configure FFmpeg with "--enable-libass".
       This filter also requires a build with libavcodec and libavformat to convert the passed
       subtitles file to ASS (Advanced Substation Alpha) subtitles format.

       The filter accepts the following options:

       filename, f
           Set the filename of the subtitle file to read. It must be specified.

       original_size
           Specify the size of the original video, the video for which the ASS file was composed.
           For the syntax of this option, check the "Video size" section in the ffmpeg-utils
           manual.  Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
           correctly scale the fonts if the aspect ratio has been changed.

       fontsdir
           Set a directory path containing fonts that can be used by the filter.  These fonts
           will be used in addition to whatever the font provider uses.

       charenc
           Set subtitles input character encoding. "subtitles" filter only. Only useful if not
           UTF-8.

       stream_index, si
           Set subtitles stream index. "subtitles" filter only.

       force_style
           Override default style or script info parameters of the subtitles. It accepts a string
           containing ASS style format "KEY=VALUE" couples separated by ",".

       If the first key is not specified, it is assumed that the first value specifies the
       filename.

       For example, to render the file sub.srt on top of the input video, use the command:

               subtitles=sub.srt

       which is equivalent to:

               subtitles=filename=sub.srt

       To render the default subtitles stream from file video.mkv, use:

               subtitles=video.mkv

       To render the second subtitles stream from that file, use:

               subtitles=video.mkv:si=1

       To make the subtitles stream from sub.srt appear in transparent green "DejaVu Serif", use:

               subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'

   super2xsai
       Scale the input by 2x and smooth using the Super2xSaI (Scale and Interpolate) pixel art
       scaling algorithm.

       Useful for enlarging pixel art images without reducing sharpness.

   swaprect
       Swap two rectangular objects in video.

       This filter accepts the following options:

       w   Set object width.

       h   Set object height.

       x1  Set 1st rect x coordinate.

       y1  Set 1st rect y coordinate.

       x2  Set 2nd rect x coordinate.

       y2  Set 2nd rect y coordinate.

           All expressions are evaluated once for each frame.

       The all options are expressions containing the following constants:

       w
       h   The input width and height.

       a   same as w / h

       sar input sample aspect ratio

       dar input display aspect ratio, it is the same as (w / h) * sar

       n   The number of the input frame, starting from 0.

       t   The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.

       pos the position in the file of the input frame, NAN if unknown

   swapuv
       Swap U & V plane.

   telecine
       Apply telecine process to the video.

       This filter accepts the following options:

       first_field
           top, t
               top field first

           bottom, b
               bottom field first The default value is "top".

       pattern
           A string of numbers representing the pulldown pattern you wish to apply.  The default
           value is 23.

               Some typical patterns:

               NTSC output (30i):
               27.5p: 32222
               24p: 23 (classic)
               24p: 2332 (preferred)
               20p: 33
               18p: 334
               16p: 3444

               PAL output (25i):
               27.5p: 12222
               24p: 222222222223 ("Euro pulldown")
               16.67p: 33
               16p: 33333334

   threshold
       Apply threshold effect to video stream.

       This filter needs four video streams to perform thresholding.  First stream is stream we
       are filtering.  Second stream is holding threshold values, third stream is holding min
       values, and last, fourth stream is holding max values.

       The filter accepts the following option:

       planes
           Set which planes will be processed, unprocessed planes will be copied.  By default
           value 0xf, all planes will be processed.

       For example if first stream pixel's component value is less then threshold value of pixel
       component from 2nd threshold stream, third stream value will picked, otherwise fourth
       stream pixel component value will be picked.

       Using color source filter one can perform various types of thresholding:

       Examples

       ·   Binary threshold, using gray color as threshold:

                   ffmpeg -i 320x240.avi -f lavfi -i color=gray -f lavfi -i color=black -f lavfi -i color=white -lavfi threshold output.avi

       ·   Inverted binary threshold, using gray color as threshold:

                   ffmpeg -i 320x240.avi -f lavfi -i color=gray -f lavfi -i color=white -f lavfi -i color=black -lavfi threshold output.avi

       ·   Truncate binary threshold, using gray color as threshold:

                   ffmpeg -i 320x240.avi -f lavfi -i color=gray -i 320x240.avi -f lavfi -i color=gray -lavfi threshold output.avi

       ·   Threshold to zero, using gray color as threshold:

                   ffmpeg -i 320x240.avi -f lavfi -i color=gray -f lavfi -i color=white -i 320x240.avi -lavfi threshold output.avi

       ·   Inverted threshold to zero, using gray color as threshold:

                   ffmpeg -i 320x240.avi -f lavfi -i color=gray -i 320x240.avi -f lavfi -i color=white -lavfi threshold output.avi

   thumbnail
       Select the most representative frame in a given sequence of consecutive frames.

       The filter accepts the following options:

       n   Set the frames batch size to analyze; in a set of n frames, the filter will pick one
           of them, and then handle the next batch of n frames until the end. Default is 100.

       Since the filter keeps track of the whole frames sequence, a bigger n value will result in
       a higher memory usage, so a high value is not recommended.

       Examples

       ·   Extract one picture each 50 frames:

                   thumbnail=50

       ·   Complete example of a thumbnail creation with ffmpeg:

                   ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png

   tile
       Tile several successive frames together.

       The filter accepts the following options:

       layout
           Set the grid size (i.e. the number of lines and columns). For the syntax of this
           option, check the "Video size" section in the ffmpeg-utils manual.

       nb_frames
           Set the maximum number of frames to render in the given area. It must be less than or
           equal to wxh. The default value is 0, meaning all the area will be used.

       margin
           Set the outer border margin in pixels.

       padding
           Set the inner border thickness (i.e. the number of pixels between frames). For more
           advanced padding options (such as having different values for the edges), refer to the
           pad video filter.

       color
           Specify the color of the unused area. For the syntax of this option, check the "Color"
           section in the ffmpeg-utils manual. The default value of color is "black".

       Examples

       ·   Produce 8x8 PNG tiles of all keyframes (-skip_frame nokey) in a movie:

                   ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png

           The -vsync 0 is necessary to prevent ffmpeg from duplicating each output frame to
           accommodate the originally detected frame rate.

       ·   Display 5 pictures in an area of "3x2" frames, with 7 pixels between them, and 2
           pixels of initial margin, using mixed flat and named options:

                   tile=3x2:nb_frames=5:padding=7:margin=2

   tinterlace
       Perform various types of temporal field interlacing.

       Frames are counted starting from 1, so the first input frame is considered odd.

       The filter accepts the following options:

       mode
           Specify the mode of the interlacing. This option can also be specified as a value
           alone. See below for a list of values for this option.

           Available values are:

           merge, 0
               Move odd frames into the upper field, even into the lower field, generating a
               double height frame at half frame rate.

                        ------> time
                       Input:
                       Frame 1         Frame 2         Frame 3         Frame 4

                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444

                       Output:
                       11111                           33333
                       22222                           44444
                       11111                           33333
                       22222                           44444
                       11111                           33333
                       22222                           44444
                       11111                           33333
                       22222                           44444

           drop_even, 1
               Only output odd frames, even frames are dropped, generating a frame with unchanged
               height at half frame rate.

                        ------> time
                       Input:
                       Frame 1         Frame 2         Frame 3         Frame 4

                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444

                       Output:
                       11111                           33333
                       11111                           33333
                       11111                           33333
                       11111                           33333

           drop_odd, 2
               Only output even frames, odd frames are dropped, generating a frame with unchanged
               height at half frame rate.

                        ------> time
                       Input:
                       Frame 1         Frame 2         Frame 3         Frame 4

                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444

                       Output:
                                       22222                           44444
                                       22222                           44444
                                       22222                           44444
                                       22222                           44444

           pad, 3
               Expand each frame to full height, but pad alternate lines with black, generating a
               frame with double height at the same input frame rate.

                        ------> time
                       Input:
                       Frame 1         Frame 2         Frame 3         Frame 4

                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444

                       Output:
                       11111           .....           33333           .....
                       .....           22222           .....           44444
                       11111           .....           33333           .....
                       .....           22222           .....           44444
                       11111           .....           33333           .....
                       .....           22222           .....           44444
                       11111           .....           33333           .....
                       .....           22222           .....           44444

           interleave_top, 4
               Interleave the upper field from odd frames with the lower field from even frames,
               generating a frame with unchanged height at half frame rate.

                        ------> time
                       Input:
                       Frame 1         Frame 2         Frame 3         Frame 4

                       11111<-         22222           33333<-         44444
                       11111           22222<-         33333           44444<-
                       11111<-         22222           33333<-         44444
                       11111           22222<-         33333           44444<-

                       Output:
                       11111                           33333
                       22222                           44444
                       11111                           33333
                       22222                           44444

           interleave_bottom, 5
               Interleave the lower field from odd frames with the upper field from even frames,
               generating a frame with unchanged height at half frame rate.

                        ------> time
                       Input:
                       Frame 1         Frame 2         Frame 3         Frame 4

                       11111           22222<-         33333           44444<-
                       11111<-         22222           33333<-         44444
                       11111           22222<-         33333           44444<-
                       11111<-         22222           33333<-         44444

                       Output:
                       22222                           44444
                       11111                           33333
                       22222                           44444
                       11111                           33333

           interlacex2, 6
               Double frame rate with unchanged height. Frames are inserted each containing the
               second temporal field from the previous input frame and the first temporal field
               from the next input frame. This mode relies on the top_field_first flag. Useful
               for interlaced video displays with no field synchronisation.

                        ------> time
                       Input:
                       Frame 1         Frame 2         Frame 3         Frame 4

                       11111           22222           33333           44444
                        11111           22222           33333           44444
                       11111           22222           33333           44444
                        11111           22222           33333           44444

                       Output:
                       11111   22222   22222   33333   33333   44444   44444
                        11111   11111   22222   22222   33333   33333   44444
                       11111   22222   22222   33333   33333   44444   44444
                        11111   11111   22222   22222   33333   33333   44444

           mergex2, 7
               Move odd frames into the upper field, even into the lower field, generating a
               double height frame at same frame rate.

                        ------> time
                       Input:
                       Frame 1         Frame 2         Frame 3         Frame 4

                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444
                       11111           22222           33333           44444

                       Output:
                       11111           33333           33333           55555
                       22222           22222           44444           44444
                       11111           33333           33333           55555
                       22222           22222           44444           44444
                       11111           33333           33333           55555
                       22222           22222           44444           44444
                       11111           33333           33333           55555
                       22222           22222           44444           44444

           Numeric values are deprecated but are accepted for backward compatibility reasons.

           Default mode is "merge".

       flags
           Specify flags influencing the filter process.

           Available value for flags is:

           low_pass_filter, vlfp
               Enable vertical low-pass filtering in the filter.  Vertical low-pass filtering is
               required when creating an interlaced destination from a progressive source which
               contains high-frequency vertical detail. Filtering will reduce interlace 'twitter'
               and Moire patterning.

               Vertical low-pass filtering can only be enabled for mode interleave_top and
               interleave_bottom.

   transpose
       Transpose rows with columns in the input video and optionally flip it.

       It accepts the following parameters:

       dir Specify the transposition direction.

           Can assume the following values:

           0, 4, cclock_flip
               Rotate by 90 degrees counterclockwise and vertically flip (default), that is:

                       L.R     L.l
                       . . ->  . .
                       l.r     R.r

           1, 5, clock
               Rotate by 90 degrees clockwise, that is:

                       L.R     l.L
                       . . ->  . .
                       l.r     r.R

           2, 6, cclock
               Rotate by 90 degrees counterclockwise, that is:

                       L.R     R.r
                       . . ->  . .
                       l.r     L.l

           3, 7, clock_flip
               Rotate by 90 degrees clockwise and vertically flip, that is:

                       L.R     r.R
                       . . ->  . .
                       l.r     l.L

           For values between 4-7, the transposition is only done if the input video geometry is
           portrait and not landscape. These values are deprecated, the "passthrough" option
           should be used instead.

           Numerical values are deprecated, and should be dropped in favor of symbolic constants.

       passthrough
           Do not apply the transposition if the input geometry matches the one specified by the
           specified value. It accepts the following values:

           none
               Always apply transposition.

           portrait
               Preserve portrait geometry (when height >= width).

           landscape
               Preserve landscape geometry (when width >= height).

           Default value is "none".

       For example to rotate by 90 degrees clockwise and preserve portrait layout:

               transpose=dir=1:passthrough=portrait

       The command above can also be specified as:

               transpose=1:portrait

   trim
       Trim the input so that the output contains one continuous subpart of the input.

       It accepts the following parameters:

       start
           Specify the time of the start of the kept section, i.e. the frame with the timestamp
           start will be the first frame in the output.

       end Specify the time of the first frame that will be dropped, i.e. the frame immediately
           preceding the one with the timestamp end will be the last frame in the output.

       start_pts
           This is the same as start, except this option sets the start timestamp in timebase
           units instead of seconds.

       end_pts
           This is the same as end, except this option sets the end timestamp in timebase units
           instead of seconds.

       duration
           The maximum duration of the output in seconds.

       start_frame
           The number of the first frame that should be passed to the output.

       end_frame
           The number of the first frame that should be dropped.

       start, end, and duration are expressed as time duration specifications; see the Time
       duration section in the ffmpeg-utils(1) manual for the accepted syntax.

       Note that the first two sets of the start/end options and the duration option look at the
       frame timestamp, while the _frame variants simply count the frames that pass through the
       filter. Also note that this filter does not modify the timestamps. If you wish for the
       output timestamps to start at zero, insert a setpts filter after the trim filter.

       If multiple start or end options are set, this filter tries to be greedy and keep all the
       frames that match at least one of the specified constraints. To keep only the part that
       matches all the constraints at once, chain multiple trim filters.

       The defaults are such that all the input is kept. So it is possible to set e.g.  just the
       end values to keep everything before the specified time.

       Examples:

       ·   Drop everything except the second minute of input:

                   ffmpeg -i INPUT -vf trim=60:120

       ·   Keep only the first second:

                   ffmpeg -i INPUT -vf trim=duration=1

   unsharp
       Sharpen or blur the input video.

       It accepts the following parameters:

       luma_msize_x, lx
           Set the luma matrix horizontal size. It must be an odd integer between 3 and 23. The
           default value is 5.

       luma_msize_y, ly
           Set the luma matrix vertical size. It must be an odd integer between 3 and 23. The
           default value is 5.

       luma_amount, la
           Set the luma effect strength. It must be a floating point number, reasonable values
           lay between -1.5 and 1.5.

           Negative values will blur the input video, while positive values will sharpen it, a
           value of zero will disable the effect.

           Default value is 1.0.

       chroma_msize_x, cx
           Set the chroma matrix horizontal size. It must be an odd integer between 3 and 23. The
           default value is 5.

       chroma_msize_y, cy
           Set the chroma matrix vertical size. It must be an odd integer between 3 and 23. The
           default value is 5.

       chroma_amount, ca
           Set the chroma effect strength. It must be a floating point number, reasonable values
           lay between -1.5 and 1.5.

           Negative values will blur the input video, while positive values will sharpen it, a
           value of zero will disable the effect.

           Default value is 0.0.

       opencl
           If set to 1, specify using OpenCL capabilities, only available if FFmpeg was
           configured with "--enable-opencl". Default value is 0.

       All parameters are optional and default to the equivalent of the string '5:5:1.0:5:5:0.0'.

       Examples

       ·   Apply strong luma sharpen effect:

                   unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5

       ·   Apply a strong blur of both luma and chroma parameters:

                   unsharp=7:7:-2:7:7:-2

   uspp
       Apply ultra slow/simple postprocessing filter that compresses and decompresses the image
       at several (or - in the case of quality level 8 - all) shifts and average the results.

       The way this differs from the behavior of spp is that uspp actually encodes & decodes each
       case with libavcodec Snow, whereas spp uses a simplified intra only 8x8 DCT similar to
       MJPEG.

       The filter accepts the following options:

       quality
           Set quality. This option defines the number of levels for averaging. It accepts an
           integer in the range 0-8. If set to 0, the filter will have no effect. A value of 8
           means the higher quality. For each increment of that value the speed drops by a factor
           of approximately 2.  Default value is 3.

       qp  Force a constant quantization parameter. If not set, the filter will use the QP from
           the video stream (if available).

   vaguedenoiser
       Apply a wavelet based denoiser.

       It transforms each frame from the video input into the wavelet domain, using Cohen-
       Daubechies-Feauveau 9/7. Then it applies some filtering to the obtained coefficients. It
       does an inverse wavelet transform after.  Due to wavelet properties, it should give a nice
       smoothed result, and reduced noise, without blurring picture features.

       This filter accepts the following options:

       threshold
           The filtering strength. The higher, the more filtered the video will be.  Hard
           thresholding can use a higher threshold than soft thresholding before the video looks
           overfiltered.

       method
           The filtering method the filter will use.

           It accepts the following values:

           hard
               All values under the threshold will be zeroed.

           soft
               All values under the threshold will be zeroed. All values above will be reduced by
               the threshold.

           garrote
               Scales or nullifies coefficients - intermediary between (more) soft and (less)
               hard thresholding.

       nsteps
           Number of times, the wavelet will decompose the picture. Picture can't be decomposed
           beyond a particular point (typically, 8 for a 640x480 frame - as 2^9 = 512 > 480)

       percent
           Partial of full denoising (limited coefficients shrinking), from 0 to 100.

       planes
           A list of the planes to process. By default all planes are processed.

   vectorscope
       Display 2 color component values in the two dimensional graph (which is called a
       vectorscope).

       This filter accepts the following options:

       mode, m
           Set vectorscope mode.

           It accepts the following values:

           gray
               Gray values are displayed on graph, higher brightness means more pixels have same
               component color value on location in graph. This is the default mode.

           color
               Gray values are displayed on graph. Surrounding pixels values which are not
               present in video frame are drawn in gradient of 2 color components which are set
               by option "x" and "y". The 3rd color component is static.

           color2
               Actual color components values present in video frame are displayed on graph.

           color3
               Similar as color2 but higher frequency of same values "x" and "y" on graph
               increases value of another color component, which is luminance by default values
               of "x" and "y".

           color4
               Actual colors present in video frame are displayed on graph. If two different
               colors map to same position on graph then color with higher value of component not
               present in graph is picked.

           color5
               Gray values are displayed on graph. Similar to "color" but with 3rd color
               component picked from radial gradient.

       x   Set which color component will be represented on X-axis. Default is 1.

       y   Set which color component will be represented on Y-axis. Default is 2.

       intensity, i
           Set intensity, used by modes: gray, color, color3 and color5 for increasing brightness
           of color component which represents frequency of (X, Y) location in graph.

       envelope, e
           none
               No envelope, this is default.

           instant
               Instant envelope, even darkest single pixel will be clearly highlighted.

           peak
               Hold maximum and minimum values presented in graph over time. This way you can
               still spot out of range values without constantly looking at vectorscope.

           peak+instant
               Peak and instant envelope combined together.

       graticule, g
           Set what kind of graticule to draw.

           none
           green
           color
       opacity, o
           Set graticule opacity.

       flags, f
           Set graticule flags.

           white
               Draw graticule for white point.

           black
               Draw graticule for black point.

           name
               Draw color points short names.

       bgopacity, b
           Set background opacity.

       lthreshold, l
           Set low threshold for color component not represented on X or Y axis.  Values lower
           than this value will be ignored. Default is 0.  Note this value is multiplied with
           actual max possible value one pixel component can have. So for 8-bit input and low
           threshold value of 0.1 actual threshold is 0.1 * 255 = 25.

       hthreshold, h
           Set high threshold for color component not represented on X or Y axis.  Values higher
           than this value will be ignored. Default is 1.  Note this value is multiplied with
           actual max possible value one pixel component can have. So for 8-bit input and high
           threshold value of 0.9 actual threshold is 0.9 * 255 = 230.

       colorspace, c
           Set what kind of colorspace to use when drawing graticule.

           auto
           601
           709

           Default is auto.

   vidstabdetect
       Analyze video stabilization/deshaking. Perform pass 1 of 2, see vidstabtransform for pass
       2.

       This filter generates a file with relative translation and rotation transform information
       about subsequent frames, which is then used by the vidstabtransform filter.

       To enable compilation of this filter you need to configure FFmpeg with
       "--enable-libvidstab".

       This filter accepts the following options:

       result
           Set the path to the file used to write the transforms information.  Default value is
           transforms.trf.

       shakiness
           Set how shaky the video is and how quick the camera is. It accepts an integer in the
           range 1-10, a value of 1 means little shakiness, a value of 10 means strong shakiness.
           Default value is 5.

       accuracy
           Set the accuracy of the detection process. It must be a value in the range 1-15. A
           value of 1 means low accuracy, a value of 15 means high accuracy. Default value is 15.

       stepsize
           Set stepsize of the search process. The region around minimum is scanned with 1 pixel
           resolution. Default value is 6.

       mincontrast
           Set minimum contrast. Below this value a local measurement field is discarded. Must be
           a floating point value in the range 0-1. Default value is 0.3.

       tripod
           Set reference frame number for tripod mode.

           If enabled, the motion of the frames is compared to a reference frame in the filtered
           stream, identified by the specified number. The idea is to compensate all movements in
           a more-or-less static scene and keep the camera view absolutely still.

           If set to 0, it is disabled. The frames are counted starting from 1.

       show
           Show fields and transforms in the resulting frames. It accepts an integer in the range
           0-2. Default value is 0, which disables any visualization.

       Examples

       ·   Use default values:

                   vidstabdetect

       ·   Analyze strongly shaky movie and put the results in file mytransforms.trf:

                   vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"

       ·   Visualize the result of internal transformations in the resulting video:

                   vidstabdetect=show=1

       ·   Analyze a video with medium shakiness using ffmpeg:

                   ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi

   vidstabtransform
       Video stabilization/deshaking: pass 2 of 2, see vidstabdetect for pass 1.

       Read a file with transform information for each frame and apply/compensate them. Together
       with the vidstabdetect filter this can be used to deshake videos. See also
       <http://public.hronopik.de/vid.stab>. It is important to also use the unsharp filter, see
       below.

       To enable compilation of this filter you need to configure FFmpeg with
       "--enable-libvidstab".

       Options

       input
           Set path to the file used to read the transforms. Default value is transforms.trf.

       smoothing
           Set the number of frames (value*2 + 1) used for lowpass filtering the camera
           movements. Default value is 10.

           For example a number of 10 means that 21 frames are used (10 in the past and 10 in the
           future) to smoothen the motion in the video. A larger value leads to a smoother video,
           but limits the acceleration of the camera (pan/tilt movements). 0 is a special case
           where a static camera is simulated.

       optalgo
           Set the camera path optimization algorithm.

           Accepted values are:

           gauss
               gaussian kernel low-pass filter on camera motion (default)

           avg averaging on transformations

       maxshift
           Set maximal number of pixels to translate frames. Default value is -1, meaning no
           limit.

       maxangle
           Set maximal angle in radians (degree*PI/180) to rotate frames. Default value is -1,
           meaning no limit.

       crop
           Specify how to deal with borders that may be visible due to movement compensation.

           Available values are:

           keep
               keep image information from previous frame (default)

           black
               fill the border black

       invert
           Invert transforms if set to 1. Default value is 0.

       relative
           Consider transforms as relative to previous frame if set to 1, absolute if set to 0.
           Default value is 0.

       zoom
           Set percentage to zoom. A positive value will result in a zoom-in effect, a negative
           value in a zoom-out effect. Default value is 0 (no zoom).

       optzoom
           Set optimal zooming to avoid borders.

           Accepted values are:

           0   disabled

           1   optimal static zoom value is determined (only very strong movements will lead to
               visible borders) (default)

           2   optimal adaptive zoom value is determined (no borders will be visible), see
               zoomspeed

           Note that the value given at zoom is added to the one calculated here.

       zoomspeed
           Set percent to zoom maximally each frame (enabled when optzoom is set to 2). Range is
           from 0 to 5, default value is 0.25.

       interpol
           Specify type of interpolation.

           Available values are:

           no  no interpolation

           linear
               linear only horizontal

           bilinear
               linear in both directions (default)

           bicubic
               cubic in both directions (slow)

       tripod
           Enable virtual tripod mode if set to 1, which is equivalent to
           "relative=0:smoothing=0". Default value is 0.

           Use also "tripod" option of vidstabdetect.

       debug
           Increase log verbosity if set to 1. Also the detected global motions are written to
           the temporary file global_motions.trf. Default value is 0.

       Examples

       ·   Use ffmpeg for a typical stabilization with default values:

                   ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg

           Note the use of the unsharp filter which is always recommended.

       ·   Zoom in a bit more and load transform data from a given file:

                   vidstabtransform=zoom=5:input="mytransforms.trf"

       ·   Smoothen the video even more:

                   vidstabtransform=smoothing=30

   vflip
       Flip the input video vertically.

       For example, to vertically flip a video with ffmpeg:

               ffmpeg -i in.avi -vf "vflip" out.avi

   vignette
       Make or reverse a natural vignetting effect.

       The filter accepts the following options:

       angle, a
           Set lens angle expression as a number of radians.

           The value is clipped in the "[0,PI/2]" range.

           Default value: "PI/5"

       x0
       y0  Set center coordinates expressions. Respectively "w/2" and "h/2" by default.

       mode
           Set forward/backward mode.

           Available modes are:

           forward
               The larger the distance from the central point, the darker the image becomes.

           backward
               The larger the distance from the central point, the brighter the image becomes.
               This can be used to reverse a vignette effect, though there is no automatic
               detection to extract the lens angle and other settings (yet). It can also be used
               to create a burning effect.

           Default value is forward.

       eval
           Set evaluation mode for the expressions (angle, x0, y0).

           It accepts the following values:

           init
               Evaluate expressions only once during the filter initialization.

           frame
               Evaluate expressions for each incoming frame. This is way slower than the init
               mode since it requires all the scalers to be re-computed, but it allows advanced
               dynamic expressions.

           Default value is init.

       dither
           Set dithering to reduce the circular banding effects. Default is 1 (enabled).

       aspect
           Set vignette aspect. This setting allows one to adjust the shape of the vignette.
           Setting this value to the SAR of the input will make a rectangular vignetting
           following the dimensions of the video.

           Default is "1/1".

       Expressions

       The alpha, x0 and y0 expressions can contain the following parameters.

       w
       h   input width and height

       n   the number of input frame, starting from 0

       pts the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in TB
           units, NAN if undefined

       r   frame rate of the input video, NAN if the input frame rate is unknown

       t   the PTS (Presentation TimeStamp) of the filtered video frame, expressed in seconds,
           NAN if undefined

       tb  time base of the input video

       Examples

       ·   Apply simple strong vignetting effect:

                   vignette=PI/4

       ·   Make a flickering vignetting:

                   vignette='PI/4+random(1)*PI/50':eval=frame

   vstack
       Stack input videos vertically.

       All streams must be of same pixel format and of same width.

       Note that this filter is faster than using overlay and pad filter to create same output.

       The filter accept the following option:

       inputs
           Set number of input streams. Default is 2.

       shortest
           If set to 1, force the output to terminate when the shortest input terminates. Default
           value is 0.

   w3fdif
       Deinterlace the input video ("w3fdif" stands for "Weston 3 Field Deinterlacing Filter").

       Based on the process described by Martin Weston for BBC R&D, and implemented based on the
       de-interlace algorithm written by Jim Easterbrook for BBC R&D, the Weston 3 field
       deinterlacing filter uses filter coefficients calculated by BBC R&D.

       There are two sets of filter coefficients, so called "simple": and "complex". Which set of
       filter coefficients is used can be set by passing an optional parameter:

       filter
           Set the interlacing filter coefficients. Accepts one of the following values:

           simple
               Simple filter coefficient set.

           complex
               More-complex filter coefficient set.

           Default value is complex.

       deint
           Specify which frames to deinterlace. Accept one of the following values:

           all Deinterlace all frames,

           interlaced
               Only deinterlace frames marked as interlaced.

           Default value is all.

   waveform
       Video waveform monitor.

       The waveform monitor plots color component intensity. By default luminance only. Each
       column of the waveform corresponds to a column of pixels in the source video.

       It accepts the following options:

       mode, m
           Can be either "row", or "column". Default is "column".  In row mode, the graph on the
           left side represents color component value 0 and the right side represents value =
           255. In column mode, the top side represents color component value = 0 and bottom side
           represents value = 255.

       intensity, i
           Set intensity. Smaller values are useful to find out how many values of the same
           luminance are distributed across input rows/columns.  Default value is 0.04. Allowed
           range is [0, 1].

       mirror, r
           Set mirroring mode. 0 means unmirrored, 1 means mirrored.  In mirrored mode, higher
           values will be represented on the left side for "row" mode and at the top for "column"
           mode. Default is 1 (mirrored).

       display, d
           Set display mode.  It accepts the following values:

           overlay
               Presents information identical to that in the "parade", except that the graphs
               representing color components are superimposed directly over one another.

               This display mode makes it easier to spot relative differences or similarities in
               overlapping areas of the color components that are supposed to be identical, such
               as neutral whites, grays, or blacks.

           stack
               Display separate graph for the color components side by side in "row" mode or one
               below the other in "column" mode.

           parade
               Display separate graph for the color components side by side in "column" mode or
               one below the other in "row" mode.

               Using this display mode makes it easy to spot color casts in the highlights and
               shadows of an image, by comparing the contours of the top and the bottom graphs of
               each waveform. Since whites, grays, and blacks are characterized by exactly equal
               amounts of red, green, and blue, neutral areas of the picture should display three
               waveforms of roughly equal width/height. If not, the correction is easy to perform
               by making level adjustments the three waveforms.

           Default is "stack".

       components, c
           Set which color components to display. Default is 1, which means only luminance or red
           color component if input is in RGB colorspace. If is set for example to 7 it will
           display all 3 (if) available color components.

       envelope, e
           none
               No envelope, this is default.

           instant
               Instant envelope, minimum and maximum values presented in graph will be easily
               visible even with small "step" value.

           peak
               Hold minimum and maximum values presented in graph across time. This way you can
               still spot out of range values without constantly looking at waveforms.

           peak+instant
               Peak and instant envelope combined together.

       filter, f
           lowpass
               No filtering, this is default.

           flat
               Luma and chroma combined together.

           aflat
               Similar as above, but shows difference between blue and red chroma.

           chroma
               Displays only chroma.

           color
               Displays actual color value on waveform.

           acolor
               Similar as above, but with luma showing frequency of chroma values.

       graticule, g
           Set which graticule to display.

           none
               Do not display graticule.

           green
               Display green graticule showing legal broadcast ranges.

       opacity, o
           Set graticule opacity.

       flags, fl
           Set graticule flags.

           numbers
               Draw numbers above lines. By default enabled.

           dots
               Draw dots instead of lines.

       scale, s
           Set scale used for displaying graticule.

           digital
           millivolts
           ire

           Default is digital.

       bgopacity, b
           Set background opacity.

   weave
       The "weave" takes a field-based video input and join each two sequential fields into
       single frame, producing a new double height clip with half the frame rate and half the
       frame count.

       It accepts the following option:

       first_field
           Set first field. Available values are:

           top, t
               Set the frame as top-field-first.

           bottom, b
               Set the frame as bottom-field-first.

       Examples

       ·   Interlace video using select and separatefields filter:

                   separatefields,select=eq(mod(n,4),0)+eq(mod(n,4),3),weave

   xbr
       Apply the xBR high-quality magnification filter which is designed for pixel art. It
       follows a set of edge-detection rules, see
       <http://www.libretro.com/forums/viewtopic.php?f=6&t=134>.

       It accepts the following option:

       n   Set the scaling dimension: 2 for "2xBR", 3 for "3xBR" and 4 for "4xBR".  Default is 3.

   yadif
       Deinterlace the input video ("yadif" means "yet another deinterlacing filter").

       It accepts the following parameters:

       mode
           The interlacing mode to adopt. It accepts one of the following values:

           0, send_frame
               Output one frame for each frame.

           1, send_field
               Output one frame for each field.

           2, send_frame_nospatial
               Like "send_frame", but it skips the spatial interlacing check.

           3, send_field_nospatial
               Like "send_field", but it skips the spatial interlacing check.

           The default value is "send_frame".

       parity
           The picture field parity assumed for the input interlaced video. It accepts one of the
           following values:

           0, tff
               Assume the top field is first.

           1, bff
               Assume the bottom field is first.

           -1, auto
               Enable automatic detection of field parity.

           The default value is "auto".  If the interlacing is unknown or the decoder does not
           export this information, top field first will be assumed.

       deint
           Specify which frames to deinterlace. Accept one of the following values:

           0, all
               Deinterlace all frames.

           1, interlaced
               Only deinterlace frames marked as interlaced.

           The default value is "all".

   zoompan
       Apply Zoom & Pan effect.

       This filter accepts the following options:

       zoom, z
           Set the zoom expression. Default is 1.

       x
       y   Set the x and y expression. Default is 0.

       d   Set the duration expression in number of frames.  This sets for how many number of
           frames effect will last for single input image.

       s   Set the output image size, default is 'hd720'.

       fps Set the output frame rate, default is '25'.

       Each expression can contain the following constants:

       in_w, iw
           Input width.

       in_h, ih
           Input height.

       out_w, ow
           Output width.

       out_h, oh
           Output height.

       in  Input frame count.

       on  Output frame count.

       x
       y   Last calculated 'x' and 'y' position from 'x' and 'y' expression for current input
           frame.

       px
       py  'x' and 'y' of last output frame of previous input frame or 0 when there was not yet
           such frame (first input frame).

       zoom
           Last calculated zoom from 'z' expression for current input frame.

       pzoom
           Last calculated zoom of last output frame of previous input frame.

       duration
           Number of output frames for current input frame. Calculated from 'd' expression for
           each input frame.

       pduration
           number of output frames created for previous input frame

       a   Rational number: input width / input height

       sar sample aspect ratio

       dar display aspect ratio

       Examples

       ·   Zoom-in up to 1.5 and pan at same time to some spot near center of picture:

                   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

       ·   Zoom-in up to 1.5 and pan always at center of picture:

                   zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'

       ·   Same as above but without pausing:

                   zoompan=z='min(max(zoom,pzoom)+0.0015,1.5)':d=1:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'

   zscale
       Scale (resize) the input video, using the z.lib library:
       https://github.com/sekrit-twc/zimg.

       The zscale filter forces the output display aspect ratio to be the same as the input, by
       changing the output sample aspect ratio.

       If the input image format is different from the format requested by the next filter, the
       zscale filter will convert the input to the requested format.

       Options

       The filter accepts the following options.

       width, w
       height, h
           Set the output video dimension expression. Default value is the input dimension.

           If the width or w is 0, the input width is used for the output.  If the height or h is
           0, the input height is used for the output.

           If one of the values is -1, the zscale filter will use a value that maintains the
           aspect ratio of the input image, calculated from the other specified dimension. If
           both of them are -1, the input size is used

           If one of the values is -n with n > 1, the zscale filter will also use a value that
           maintains the aspect ratio of the input image, calculated from the other specified
           dimension. After that it will, however, make sure that the calculated dimension is
           divisible by n and adjust the value if necessary.

           See below for the list of accepted constants for use in the dimension expression.

       size, s
           Set the video size. For the syntax of this option, check the "Video size" section in
           the ffmpeg-utils manual.

       dither, d
           Set the dither type.

           Possible values are:

           none
           ordered
           random
           error_diffusion

           Default is none.

       filter, f
           Set the resize filter type.

           Possible values are:

           point
           bilinear
           bicubic
           spline16
           spline36
           lanczos

           Default is bilinear.

       range, r
           Set the color range.

           Possible values are:

           input
           limited
           full

           Default is same as input.

       primaries, p
           Set the color primaries.

           Possible values are:

           input
           709
           unspecified
           170m
           240m
           2020

           Default is same as input.

       transfer, t
           Set the transfer characteristics.

           Possible values are:

           input
           709
           unspecified
           601
           linear
           2020_10
           2020_12
           smpte2084
           iec61966-2-1
           arib-std-b67

           Default is same as input.

       matrix, m
           Set the colorspace matrix.

           Possible value are:

           input
           709
           unspecified
           470bg
           170m
           2020_ncl
           2020_cl

           Default is same as input.

       rangein, rin
           Set the input color range.

           Possible values are:

           input
           limited
           full

           Default is same as input.

       primariesin, pin
           Set the input color primaries.

           Possible values are:

           input
           709
           unspecified
           170m
           240m
           2020

           Default is same as input.

       transferin, tin
           Set the input transfer characteristics.

           Possible values are:

           input
           709
           unspecified
           601
           linear
           2020_10
           2020_12

           Default is same as input.

       matrixin, min
           Set the input colorspace matrix.

           Possible value are:

           input
           709
           unspecified
           470bg
           170m
           2020_ncl
           2020_cl
       chromal, c
           Set the output chroma location.

           Possible values are:

           input
           left
           center
           topleft
           top
           bottomleft
           bottom
       chromalin, cin
           Set the input chroma location.

           Possible values are:

           input
           left
           center
           topleft
           top
           bottomleft
           bottom
       npl Set the nominal peak luminance.

       The values of the w and h options are expressions containing the following constants:

       in_w
       in_h
           The input width and height

       iw
       ih  These are the same as in_w and in_h.

       out_w
       out_h
           The output (scaled) width and height

       ow
       oh  These are the same as out_w and out_h

       a   The same as iw / ih

       sar input sample aspect ratio

       dar The input display aspect ratio. Calculated from "(iw / ih) * sar".

       hsub
       vsub
           horizontal and vertical input chroma subsample values. For example for the pixel
           format "yuv422p" hsub is 2 and vsub is 1.

       ohsub
       ovsub
           horizontal and vertical output chroma subsample values. For example for the pixel
           format "yuv422p" hsub is 2 and vsub is 1.

VIDEO SOURCES

       Below is a description of the currently available video sources.

   buffer
       Buffer video frames, and make them available to the filter chain.

       This source is mainly intended for a programmatic use, in particular through the interface
       defined in libavfilter/vsrc_buffer.h.

       It accepts the following parameters:

       video_size
           Specify the size (width and height) of the buffered video frames. For the syntax of
           this option, check the "Video size" section in the ffmpeg-utils manual.

       width
           The input video width.

       height
           The input video height.

       pix_fmt
           A string representing the pixel format of the buffered video frames.  It may be a
           number corresponding to a pixel format, or a pixel format name.

       time_base
           Specify the timebase assumed by the timestamps of the buffered frames.

       frame_rate
           Specify the frame rate expected for the video stream.

       pixel_aspect, sar
           The sample (pixel) aspect ratio of the input video.

       sws_param
           Specify the optional parameters to be used for the scale filter which is automatically
           inserted when an input change is detected in the input size or format.

       hw_frames_ctx
           When using a hardware pixel format, this should be a reference to an AVHWFramesContext
           describing input frames.

       For example:

               buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1

       will instruct the source to accept video frames with size 320x240 and with format
       "yuv410p", assuming 1/24 as the timestamps timebase and square pixels (1:1 sample aspect
       ratio).  Since the pixel format with name "yuv410p" corresponds to the number 6 (check the
       enum AVPixelFormat definition in libavutil/pixfmt.h), this example corresponds to:

               buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1

       Alternatively, the options can be specified as a flat string, but this syntax is
       deprecated:

       width:height:pix_fmt:time_base.num:time_base.den:pixel_aspect.num:pixel_aspect.den[:sws_param]

   cellauto
       Create a pattern generated by an elementary cellular automaton.

       The initial state of the cellular automaton can be defined through the filename and
       pattern options. If such options are not specified an initial state is created randomly.

       At each new frame a new row in the video is filled with the result of the cellular
       automaton next generation. The behavior when the whole frame is filled is defined by the
       scroll option.

       This source accepts the following options:

       filename, f
           Read the initial cellular automaton state, i.e. the starting row, from the specified
           file.  In the file, each non-whitespace character is considered an alive cell, a
           newline will terminate the row, and further characters in the file will be ignored.

       pattern, p
           Read the initial cellular automaton state, i.e. the starting row, from the specified
           string.

           Each non-whitespace character in the string is considered an alive cell, a newline
           will terminate the row, and further characters in the string will be ignored.

       rate, r
           Set the video rate, that is the number of frames generated per second.  Default is 25.

       random_fill_ratio, ratio
           Set the random fill ratio for the initial cellular automaton row. It is a floating
           point number value ranging from 0 to 1, defaults to 1/PHI.

           This option is ignored when a file or a pattern is specified.

       random_seed, seed
           Set the seed for filling randomly the initial row, must be an integer included between
           0 and UINT32_MAX. If not specified, or if explicitly set to -1, the filter will try to
           use a good random seed on a best effort basis.

       rule
           Set the cellular automaton rule, it is a number ranging from 0 to 255.  Default value
           is 110.

       size, s
           Set the size of the output video. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.

           If filename or pattern is specified, the size is set by default to the width of the
           specified initial state row, and the height is set to width * PHI.

           If size is set, it must contain the width of the specified pattern string, and the
           specified pattern will be centered in the larger row.

           If a filename or a pattern string is not specified, the size value defaults to
           "320x518" (used for a randomly generated initial state).

       scroll
           If set to 1, scroll the output upward when all the rows in the output have been
           already filled. If set to 0, the new generated row will be written over the top row
           just after the bottom row is filled.  Defaults to 1.

       start_full, full
           If set to 1, completely fill the output with generated rows before outputting the
           first frame.  This is the default behavior, for disabling set the value to 0.

       stitch
           If set to 1, stitch the left and right row edges together.  This is the default
           behavior, for disabling set the value to 0.

       Examples

       ·   Read the initial state from pattern, and specify an output of size 200x400.

                   cellauto=f=pattern:s=200x400

       ·   Generate a random initial row with a width of 200 cells, with a fill ratio of 2/3:

                   cellauto=ratio=2/3:s=200x200

       ·   Create a pattern generated by rule 18 starting by a single alive cell centered on an
           initial row with width 100:

                   cellauto=p=@s=100x400:full=0:rule=18

       ·   Specify a more elaborated initial pattern:

                   cellauto=p='@@ @ @@':s=100x400:full=0:rule=18

   coreimagesrc
       Video source generated on GPU using Apple's CoreImage API on OSX.

       This video source is a specialized version of the coreimage video filter.  Use a core
       image generator at the beginning of the applied filterchain to generate the content.

       The coreimagesrc video source accepts the following options:

       list_generators
           List all available generators along with all their respective options as well as
           possible minimum and maximum values along with the default values.

                   list_generators=true

       size, s
           Specify the size of the sourced video. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  The default value is "320x240".

       rate, r
           Specify the frame rate of the sourced video, as the number of frames generated per
           second. It has to be a string in the format frame_rate_num/frame_rate_den, an integer
           number, a floating point number or a valid video frame rate abbreviation. The default
           value is "25".

       sar Set the sample aspect ratio of the sourced video.

       duration, d
           Set the duration of the sourced video. See the Time duration section in the
           ffmpeg-utils(1) manual for the accepted syntax.

           If not specified, or the expressed duration is negative, the video is supposed to be
           generated forever.

       Additionally, all options of the coreimage video filter are accepted.  A complete
       filterchain can be used for further processing of the generated input without CPU-HOST
       transfer. See coreimage documentation and examples for details.

       Examples

       ·   Use CIQRCodeGenerator to create a QR code for the FFmpeg homepage, given as complete
           and escaped command-line for Apple's standard bash shell:

                   ffmpeg -f lavfi -i coreimagesrc=s=100x100:filter=CIQRCodeGenerator@inputMessage=https\\\\\://FFmpeg.org/@inputCorrectionLevel=H -frames:v 1 QRCode.png

           This example is equivalent to the QRCode example of coreimage without the need for a
           nullsrc video source.

   mandelbrot
       Generate a Mandelbrot set fractal, and progressively zoom towards the point specified with
       start_x and start_y.

       This source accepts the following options:

       end_pts
           Set the terminal pts value. Default value is 400.

       end_scale
           Set the terminal scale value.  Must be a floating point value. Default value is 0.3.

       inner
           Set the inner coloring mode, that is the algorithm used to draw the Mandelbrot fractal
           internal region.

           It shall assume one of the following values:

           black
               Set black mode.

           convergence
               Show time until convergence.

           mincol
               Set color based on point closest to the origin of the iterations.

           period
               Set period mode.

           Default value is mincol.

       bailout
           Set the bailout value. Default value is 10.0.

       maxiter
           Set the maximum of iterations performed by the rendering algorithm. Default value is
           7189.

       outer
           Set outer coloring mode.  It shall assume one of following values:

           iteration_count
               Set iteration cound mode.

           normalized_iteration_count
               set normalized iteration count mode.

           Default value is normalized_iteration_count.

       rate, r
           Set frame rate, expressed as number of frames per second. Default value is "25".

       size, s
           Set frame size. For the syntax of this option, check the "Video size" section in the
           ffmpeg-utils manual. Default value is "640x480".

       start_scale
           Set the initial scale value. Default value is 3.0.

       start_x
           Set the initial x position. Must be a floating point value between -100 and 100.
           Default value is -0.743643887037158704752191506114774.

       start_y
           Set the initial y position. Must be a floating point value between -100 and 100.
           Default value is -0.131825904205311970493132056385139.

   mptestsrc
       Generate various test patterns, as generated by the MPlayer test filter.

       The size of the generated video is fixed, and is 256x256.  This source is useful in
       particular for testing encoding features.

       This source accepts the following options:

       rate, r
           Specify the frame rate of the sourced video, as the number of frames generated per
           second. It has to be a string in the format frame_rate_num/frame_rate_den, an integer
           number, a floating point number or a valid video frame rate abbreviation. The default
           value is "25".

       duration, d
           Set the duration of the sourced video. See the Time duration section in the
           ffmpeg-utils(1) manual for the accepted syntax.

           If not specified, or the expressed duration is negative, the video is supposed to be
           generated forever.

       test, t
           Set the number or the name of the test to perform. Supported tests are:

           dc_luma
           dc_chroma
           freq_luma
           freq_chroma
           amp_luma
           amp_chroma
           cbp
           mv
           ring1
           ring2
           all

           Default value is "all", which will cycle through the list of all tests.

       Some examples:

               mptestsrc=t=dc_luma

       will generate a "dc_luma" test pattern.

   frei0r_src
       Provide a frei0r source.

       To enable compilation of this filter you need to install the frei0r header and configure
       FFmpeg with "--enable-frei0r".

       This source accepts the following parameters:

       size
           The size of the video to generate. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.

       framerate
           The framerate of the generated video. It may be a string of the form num/den or a
           frame rate abbreviation.

       filter_name
           The name to the frei0r source to load. For more information regarding frei0r and how
           to set the parameters, read the frei0r section in the video filters documentation.

       filter_params
           A '|'-separated list of parameters to pass to the frei0r source.

       For example, to generate a frei0r partik0l source with size 200x200 and frame rate 10
       which is overlaid on the overlay filter main input:

               frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay

   life
       Generate a life pattern.

       This source is based on a generalization of John Conway's life game.

       The sourced input represents a life grid, each pixel represents a cell which can be in one
       of two possible states, alive or dead. Every cell interacts with its eight neighbours,
       which are the cells that are horizontally, vertically, or diagonally adjacent.

       At each interaction the grid evolves according to the adopted rule, which specifies the
       number of neighbor alive cells which will make a cell stay alive or born. The rule option
       allows one to specify the rule to adopt.

       This source accepts the following options:

       filename, f
           Set the file from which to read the initial grid state. In the file, each non-
           whitespace character is considered an alive cell, and newline is used to delimit the
           end of each row.

           If this option is not specified, the initial grid is generated randomly.

       rate, r
           Set the video rate, that is the number of frames generated per second.  Default is 25.

       random_fill_ratio, ratio
           Set the random fill ratio for the initial random grid. It is a floating point number
           value ranging from 0 to 1, defaults to 1/PHI.  It is ignored when a file is specified.

       random_seed, seed
           Set the seed for filling the initial random grid, must be an integer included between
           0 and UINT32_MAX. If not specified, or if explicitly set to -1, the filter will try to
           use a good random seed on a best effort basis.

       rule
           Set the life rule.

           A rule can be specified with a code of the kind "SNS/BNB", where NS and NB are
           sequences of numbers in the range 0-8, NS specifies the number of alive neighbor cells
           which make a live cell stay alive, and NB the number of alive neighbor cells which
           make a dead cell to become alive (i.e. to "born").  "s" and "b" can be used in place
           of "S" and "B", respectively.

           Alternatively a rule can be specified by an 18-bits integer. The 9 high order bits are
           used to encode the next cell state if it is alive for each number of neighbor alive
           cells, the low order bits specify the rule for "borning" new cells. Higher order bits
           encode for an higher number of neighbor cells.  For example the number 6153 =
           "(12<<9)+9" specifies a stay alive rule of 12 and a born rule of 9, which corresponds
           to "S23/B03".

           Default value is "S23/B3", which is the original Conway's game of life rule, and will
           keep a cell alive if it has 2 or 3 neighbor alive cells, and will born a new cell if
           there are three alive cells around a dead cell.

       size, s
           Set the size of the output video. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.

           If filename is specified, the size is set by default to the same size of the input
           file. If size is set, it must contain the size specified in the input file, and the
           initial grid defined in that file is centered in the larger resulting area.

           If a filename is not specified, the size value defaults to "320x240" (used for a
           randomly generated initial grid).

       stitch
           If set to 1, stitch the left and right grid edges together, and the top and bottom
           edges also. Defaults to 1.

       mold
           Set cell mold speed. If set, a dead cell will go from death_color to mold_color with a
           step of mold. mold can have a value from 0 to 255.

       life_color
           Set the color of living (or new born) cells.

       death_color
           Set the color of dead cells. If mold is set, this is the first color used to represent
           a dead cell.

       mold_color
           Set mold color, for definitely dead and moldy cells.

           For the syntax of these 3 color options, check the "Color" section in the ffmpeg-utils
           manual.

       Examples

       ·   Read a grid from pattern, and center it on a grid of size 300x300 pixels:

                   life=f=pattern:s=300x300

       ·   Generate a random grid of size 200x200, with a fill ratio of 2/3:

                   life=ratio=2/3:s=200x200

       ·   Specify a custom rule for evolving a randomly generated grid:

                   life=rule=S14/B34

       ·   Full example with slow death effect (mold) using ffplay:

                   ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16

   allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc,
       testsrc2, yuvtestsrc
       The "allrgb" source returns frames of size 4096x4096 of all rgb colors.

       The "allyuv" source returns frames of size 4096x4096 of all yuv colors.

       The "color" source provides an uniformly colored input.

       The "haldclutsrc" source provides an identity Hald CLUT. See also haldclut filter.

       The "nullsrc" source returns unprocessed video frames. It is mainly useful to be employed
       in analysis / debugging tools, or as the source for filters which ignore the input data.

       The "rgbtestsrc" source generates an RGB test pattern useful for detecting RGB vs BGR
       issues. You should see a red, green and blue stripe from top to bottom.

       The "smptebars" source generates a color bars pattern, based on the SMPTE Engineering
       Guideline EG 1-1990.

       The "smptehdbars" source generates a color bars pattern, based on the SMPTE RP 219-2002.

       The "testsrc" source generates a test video pattern, showing a color pattern, a scrolling
       gradient and a timestamp. This is mainly intended for testing purposes.

       The "testsrc2" source is similar to testsrc, but supports more pixel formats instead of
       just "rgb24". This allows using it as an input for other tests without requiring a format
       conversion.

       The "yuvtestsrc" source generates an YUV test pattern. You should see a y, cb and cr
       stripe from top to bottom.

       The sources accept the following parameters:

       color, c
           Specify the color of the source, only available in the "color" source. For the syntax
           of this option, check the "Color" section in the ffmpeg-utils manual.

       level
           Specify the level of the Hald CLUT, only available in the "haldclutsrc" source. A
           level of "N" generates a picture of "N*N*N" by "N*N*N" pixels to be used as identity
           matrix for 3D lookup tables. Each component is coded on a "1/(N*N)" scale.

       size, s
           Specify the size of the sourced video. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  The default value is "320x240".

           This option is not available with the "haldclutsrc" filter.

       rate, r
           Specify the frame rate of the sourced video, as the number of frames generated per
           second. It has to be a string in the format frame_rate_num/frame_rate_den, an integer
           number, a floating point number or a valid video frame rate abbreviation. The default
           value is "25".

       sar Set the sample aspect ratio of the sourced video.

       duration, d
           Set the duration of the sourced video. See the Time duration section in the
           ffmpeg-utils(1) manual for the accepted syntax.

           If not specified, or the expressed duration is negative, the video is supposed to be
           generated forever.

       decimals, n
           Set the number of decimals to show in the timestamp, only available in the "testsrc"
           source.

           The displayed timestamp value will correspond to the original timestamp value
           multiplied by the power of 10 of the specified value. Default value is 0.

       For example the following:

               testsrc=duration=5.3:size=qcif:rate=10

       will generate a video with a duration of 5.3 seconds, with size 176x144 and a frame rate
       of 10 frames per second.

       The following graph description will generate a red source with an opacity of 0.2, with
       size "qcif" and a frame rate of 10 frames per second.

               color=c=red@0.2:s=qcif:r=10

       If the input content is to be ignored, "nullsrc" can be used. The following command
       generates noise in the luminance plane by employing the "geq" filter:

               nullsrc=s=256x256, geq=random(1)*255:128:128

       Commands

       The "color" source supports the following commands:

       c, color
           Set the color of the created image. Accepts the same syntax of the corresponding color
           option.

VIDEO SINKS

       Below is a description of the currently available video sinks.

   buffersink
       Buffer video frames, and make them available to the end of the filter graph.

       This sink is mainly intended for programmatic use, in particular through the interface
       defined in libavfilter/buffersink.h or the options system.

       It accepts a pointer to an AVBufferSinkContext structure, which defines the incoming
       buffers' formats, to be passed as the opaque parameter to "avfilter_init_filter" for
       initialization.

   nullsink
       Null video sink: do absolutely nothing with the input video. It is mainly useful as a
       template and for use in analysis / debugging tools.

MULTIMEDIA FILTERS

       Below is a description of the currently available multimedia filters.

   abitscope
       Convert input audio to a video output, displaying the audio bit scope.

       The filter accepts the following options:

       rate, r
           Set frame rate, expressed as number of frames per second. Default value is "25".

       size, s
           Specify the video size for the output. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  Default value is "1024x256".

       colors
           Specify list of colors separated by space or by '|' which will be used to draw
           channels. Unrecognized or missing colors will be replaced by white color.

   ahistogram
       Convert input audio to a video output, displaying the volume histogram.

       The filter accepts the following options:

       dmode
           Specify how histogram is calculated.

           It accepts the following values:

           single
               Use single histogram for all channels.

           separate
               Use separate histogram for each channel.

           Default is "single".

       rate, r
           Set frame rate, expressed as number of frames per second. Default value is "25".

       size, s
           Specify the video size for the output. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  Default value is "hd720".

       scale
           Set display scale.

           It accepts the following values:

           log logarithmic

           sqrt
               square root

           cbrt
               cubic root

           lin linear

           rlog
               reverse logarithmic

           Default is "log".

       ascale
           Set amplitude scale.

           It accepts the following values:

           log logarithmic

           lin linear

           Default is "log".

       acount
           Set how much frames to accumulate in histogram.  Defauls is 1. Setting this to -1
           accumulates all frames.

       rheight
           Set histogram ratio of window height.

       slide
           Set sonogram sliding.

           It accepts the following values:

           replace
               replace old rows with new ones.

           scroll
               scroll from top to bottom.

           Default is "replace".

   aphasemeter
       Convert input audio to a video output, displaying the audio phase.

       The filter accepts the following options:

       rate, r
           Set the output frame rate. Default value is 25.

       size, s
           Set the video size for the output. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  Default value is "800x400".

       rc
       gc
       bc  Specify the red, green, blue contrast. Default values are 2, 7 and 1.  Allowed range
           is "[0, 255]".

       mpc Set color which will be used for drawing median phase. If color is "none" which is
           default, no median phase value will be drawn.

       video
           Enable video output. Default is enabled.

       The filter also exports the frame metadata "lavfi.aphasemeter.phase" which represents mean
       phase of current audio frame. Value is in range "[-1, 1]".  The "-1" means left and right
       channels are completely out of phase and 1 means channels are in phase.

   avectorscope
       Convert input audio to a video output, representing the audio vector scope.

       The filter is used to measure the difference between channels of stereo audio stream. A
       monoaural signal, consisting of identical left and right signal, results in straight
       vertical line. Any stereo separation is visible as a deviation from this line, creating a
       Lissajous figure.  If the straight (or deviation from it) but horizontal line appears this
       indicates that the left and right channels are out of phase.

       The filter accepts the following options:

       mode, m
           Set the vectorscope mode.

           Available values are:

           lissajous
               Lissajous rotated by 45 degrees.

           lissajous_xy
               Same as above but not rotated.

           polar
               Shape resembling half of circle.

           Default value is lissajous.

       size, s
           Set the video size for the output. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  Default value is "400x400".

       rate, r
           Set the output frame rate. Default value is 25.

       rc
       gc
       bc
       ac  Specify the red, green, blue and alpha contrast. Default values are 40, 160, 80 and
           255.  Allowed range is "[0, 255]".

       rf
       gf
       bf
       af  Specify the red, green, blue and alpha fade. Default values are 15, 10, 5 and 5.
           Allowed range is "[0, 255]".

       zoom
           Set the zoom factor. Default value is 1. Allowed range is "[1, 10]".

       draw
           Set the vectorscope drawing mode.

           Available values are:

           dot Draw dot for each sample.

           line
               Draw line between previous and current sample.

           Default value is dot.

       scale
           Specify amplitude scale of audio samples.

           Available values are:

           lin Linear.

           sqrt
               Square root.

           cbrt
               Cubic root.

           log Logarithmic.

       Examples

       ·   Complete example using ffplay:

                   ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
                                [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'

   bench, abench
       Benchmark part of a filtergraph.

       The filter accepts the following options:

       action
           Start or stop a timer.

           Available values are:

           start
               Get the current time, set it as frame metadata (using the key
               "lavfi.bench.start_time"), and forward the frame to the next filter.

           stop
               Get the current time and fetch the "lavfi.bench.start_time" metadata from the
               input frame metadata to get the time difference. Time difference, average, maximum
               and minimum time (respectively "t", "avg", "max" and "min") are then printed. The
               timestamps are expressed in seconds.

       Examples

       ·   Benchmark selectivecolor filter:

                   bench=start,selectivecolor=reds=-.2 .12 -.49,bench=stop

   concat
       Concatenate audio and video streams, joining them together one after the other.

       The filter works on segments of synchronized video and audio streams. All segments must
       have the same number of streams of each type, and that will also be the number of streams
       at output.

       The filter accepts the following options:

       n   Set the number of segments. Default is 2.

       v   Set the number of output video streams, that is also the number of video streams in
           each segment. Default is 1.

       a   Set the number of output audio streams, that is also the number of audio streams in
           each segment. Default is 0.

       unsafe
           Activate unsafe mode: do not fail if segments have a different format.

       The filter has v+a outputs: first v video outputs, then a audio outputs.

       There are nx(v+a) inputs: first the inputs for the first segment, in the same order as the
       outputs, then the inputs for the second segment, etc.

       Related streams do not always have exactly the same duration, for various reasons
       including codec frame size or sloppy authoring. For that reason, related synchronized
       streams (e.g. a video and its audio track) should be concatenated at once. The concat
       filter will use the duration of the longest stream in each segment (except the last one),
       and if necessary pad shorter audio streams with silence.

       For this filter to work correctly, all segments must start at timestamp 0.

       All corresponding streams must have the same parameters in all segments; the filtering
       system will automatically select a common pixel format for video streams, and a common
       sample format, sample rate and channel layout for audio streams, but other settings, such
       as resolution, must be converted explicitly by the user.

       Different frame rates are acceptable but will result in variable frame rate at output; be
       sure to configure the output file to handle it.

       Examples

       ·   Concatenate an opening, an episode and an ending, all in bilingual version (video in
           stream 0, audio in streams 1 and 2):

                   ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
                     '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
                      concat=n=3:v=1:a=2 [v] [a1] [a2]' \
                     -map '[v]' -map '[a1]' -map '[a2]' output.mkv

       ·   Concatenate two parts, handling audio and video separately, using the (a)movie
           sources, and adjusting the resolution:

                   movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
                   movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
                   [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]

           Note that a desync will happen at the stitch if the audio and video streams do not
           have exactly the same duration in the first file.

   drawgraph, adrawgraph
       Draw a graph using input video or audio metadata.

       It accepts the following parameters:

       m1  Set 1st frame metadata key from which metadata values will be used to draw a graph.

       fg1 Set 1st foreground color expression.

       m2  Set 2nd frame metadata key from which metadata values will be used to draw a graph.

       fg2 Set 2nd foreground color expression.

       m3  Set 3rd frame metadata key from which metadata values will be used to draw a graph.

       fg3 Set 3rd foreground color expression.

       m4  Set 4th frame metadata key from which metadata values will be used to draw a graph.

       fg4 Set 4th foreground color expression.

       min Set minimal value of metadata value.

       max Set maximal value of metadata value.

       bg  Set graph background color. Default is white.

       mode
           Set graph mode.

           Available values for mode is:

           bar
           dot
           line

           Default is "line".

       slide
           Set slide mode.

           Available values for slide is:

           frame
               Draw new frame when right border is reached.

           replace
               Replace old columns with new ones.

           scroll
               Scroll from right to left.

           rscroll
               Scroll from left to right.

           picture
               Draw single picture.

           Default is "frame".

       size
           Set size of graph video. For the syntax of this option, check the "Video size" section
           in the ffmpeg-utils manual.  The default value is "900x256".

           The foreground color expressions can use the following variables:

           MIN Minimal value of metadata value.

           MAX Maximal value of metadata value.

           VAL Current metadata key value.

           The color is defined as 0xAABBGGRR.

       Example using metadata from signalstats filter:

               signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255

       Example using metadata from ebur128 filter:

               ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5

   ebur128
       EBU R128 scanner filter. This filter takes an audio stream as input and outputs it
       unchanged. By default, it logs a message at a frequency of 10Hz with the Momentary
       loudness (identified by "M"), Short-term loudness ("S"), Integrated loudness ("I") and
       Loudness Range ("LRA").

       The filter also has a video output (see the video option) with a real time graph to
       observe the loudness evolution. The graphic contains the logged message mentioned above,
       so it is not printed anymore when this option is set, unless the verbose logging is set.
       The main graphing area contains the short-term loudness (3 seconds of analysis), and the
       gauge on the right is for the momentary loudness (400 milliseconds).

       More information about the Loudness Recommendation EBU R128 on
       <http://tech.ebu.ch/loudness>.

       The filter accepts the following options:

       video
           Activate the video output. The audio stream is passed unchanged whether this option is
           set or no. The video stream will be the first output stream if activated. Default is
           0.

       size
           Set the video size. This option is for video only. For the syntax of this option,
           check the "Video size" section in the ffmpeg-utils manual.  Default and minimum
           resolution is "640x480".

       meter
           Set the EBU scale meter. Default is 9. Common values are 9 and 18, respectively for
           EBU scale meter +9 and EBU scale meter +18. Any other integer value between this range
           is allowed.

       metadata
           Set metadata injection. If set to 1, the audio input will be segmented into 100ms
           output frames, each of them containing various loudness information in metadata.  All
           the metadata keys are prefixed with "lavfi.r128.".

           Default is 0.

       framelog
           Force the frame logging level.

           Available values are:

           info
               information logging level

           verbose
               verbose logging level

           By default, the logging level is set to info. If the video or the metadata options are
           set, it switches to verbose.

       peak
           Set peak mode(s).

           Available modes can be cumulated (the option is a "flag" type). Possible values are:

           none
               Disable any peak mode (default).

           sample
               Enable sample-peak mode.

               Simple peak mode looking for the higher sample value. It logs a message for
               sample-peak (identified by "SPK").

           true
               Enable true-peak mode.

               If enabled, the peak lookup is done on an over-sampled version of the input stream
               for better peak accuracy. It logs a message for true-peak.  (identified by "TPK")
               and true-peak per frame (identified by "FTPK").  This mode requires a build with
               "libswresample".

       dualmono
           Treat mono input files as "dual mono". If a mono file is intended for playback on a
           stereo system, its EBU R128 measurement will be perceptually incorrect.  If set to
           "true", this option will compensate for this effect.  Multi-channel input files are
           not affected by this option.

       panlaw
           Set a specific pan law to be used for the measurement of dual mono files.  This
           parameter is optional, and has a default value of -3.01dB.

       Examples

       ·   Real-time graph using ffplay, with a EBU scale meter +18:

                   ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"

       ·   Run an analysis with ffmpeg:

                   ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -

   interleave, ainterleave
       Temporally interleave frames from several inputs.

       "interleave" works with video inputs, "ainterleave" with audio.

       These filters read frames from several inputs and send the oldest queued frame to the
       output.

       Input streams must have well defined, monotonically increasing frame timestamp values.

       In order to submit one frame to output, these filters need to enqueue at least one frame
       for each input, so they cannot work in case one input is not yet terminated and will not
       receive incoming frames.

       For example consider the case when one input is a "select" filter which always drops input
       frames. The "interleave" filter will keep reading from that input, but it will never be
       able to send new frames to output until the input sends an end-of-stream signal.

       Also, depending on inputs synchronization, the filters will drop frames in case one input
       receives more frames than the other ones, and the queue is already filled.

       These filters accept the following options:

       nb_inputs, n
           Set the number of different inputs, it is 2 by default.

       Examples

       ·   Interleave frames belonging to different streams using ffmpeg:

                   ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi

       ·   Add flickering blur effect:

                   select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave

   metadata, ametadata
       Manipulate frame metadata.

       This filter accepts the following options:

       mode
           Set mode of operation of the filter.

           Can be one of the following:

           select
               If both "value" and "key" is set, select frames which have such metadata. If only
               "key" is set, select every frame that has such key in metadata.

           add Add new metadata "key" and "value". If key is already available do nothing.

           modify
               Modify value of already present key.

           delete
               If "value" is set, delete only keys that have such value.  Otherwise, delete key.
               If "key" is not set, delete all metadata values in the frame.

           print
               Print key and its value if metadata was found. If "key" is not set print all
               metadata values available in frame.

       key Set key used with all modes. Must be set for all modes except "print" and "delete".

       value
           Set metadata value which will be used. This option is mandatory for "modify" and "add"
           mode.

       function
           Which function to use when comparing metadata value and "value".

           Can be one of following:

           same_str
               Values are interpreted as strings, returns true if metadata value is same as
               "value".

           starts_with
               Values are interpreted as strings, returns true if metadata value starts with the
               "value" option string.

           less
               Values are interpreted as floats, returns true if metadata value is less than
               "value".

           equal
               Values are interpreted as floats, returns true if "value" is equal with metadata
               value.

           greater
               Values are interpreted as floats, returns true if metadata value is greater than
               "value".

           expr
               Values are interpreted as floats, returns true if expression from option "expr"
               evaluates to true.

       expr
           Set expression which is used when "function" is set to "expr".  The expression is
           evaluated through the eval API and can contain the following constants:

           VALUE1
               Float representation of "value" from metadata key.

           VALUE2
               Float representation of "value" as supplied by user in "value" option.

       file
           If specified in "print" mode, output is written to the named file. Instead of plain
           filename any writable url can be specified. Filename ``-'' is a shorthand for standard
           output. If "file" option is not set, output is written to the log with AV_LOG_INFO
           loglevel.

       Examples

       ·   Print all metadata values for frames with key "lavfi.singnalstats.YDIF" with values
           between 0 and 1.

                   signalstats,metadata=print:key=lavfi.signalstats.YDIF:value=0:function=expr:expr='between(VALUE1,0,1)'

       ·   Print silencedetect output to file metadata.txt.

                   silencedetect,ametadata=mode=print:file=metadata.txt

       ·   Direct all metadata to a pipe with file descriptor 4.

                   metadata=mode=print:file='pipe\:4'

   perms, aperms
       Set read/write permissions for the output frames.

       These filters are mainly aimed at developers to test direct path in the following filter
       in the filtergraph.

       The filters accept the following options:

       mode
           Select the permissions mode.

           It accepts the following values:

           none
               Do nothing. This is the default.

           ro  Set all the output frames read-only.

           rw  Set all the output frames directly writable.

           toggle
               Make the frame read-only if writable, and writable if read-only.

           random
               Set each output frame read-only or writable randomly.

       seed
           Set the seed for the random mode, must be an integer included between 0 and
           "UINT32_MAX". If not specified, or if explicitly set to "-1", the filter will try to
           use a good random seed on a best effort basis.

       Note: in case of auto-inserted filter between the permission filter and the following one,
       the permission might not be received as expected in that following filter. Inserting a
       format or aformat filter before the perms/aperms filter can avoid this problem.

   realtime, arealtime
       Slow down filtering to match real time approximatively.

       These filters will pause the filtering for a variable amount of time to match the output
       rate with the input timestamps.  They are similar to the re option to "ffmpeg".

       They accept the following options:

       limit
           Time limit for the pauses. Any pause longer than that will be considered a timestamp
           discontinuity and reset the timer. Default is 2 seconds.

   select, aselect
       Select frames to pass in output.

       This filter accepts the following options:

       expr, e
           Set expression, which is evaluated for each input frame.

           If the expression is evaluated to zero, the frame is discarded.

           If the evaluation result is negative or NaN, the frame is sent to the first output;
           otherwise it is sent to the output with index "ceil(val)-1", assuming that the input
           index starts from 0.

           For example a value of 1.2 corresponds to the output with index "ceil(1.2)-1 = 2-1 =
           1", that is the second output.

       outputs, n
           Set the number of outputs. The output to which to send the selected frame is based on
           the result of the evaluation. Default value is 1.

       The expression can contain the following constants:

       n   The (sequential) number of the filtered frame, starting from 0.

       selected_n
           The (sequential) number of the selected frame, starting from 0.

       prev_selected_n
           The sequential number of the last selected frame. It's NAN if undefined.

       TB  The timebase of the input timestamps.

       pts The PTS (Presentation TimeStamp) of the filtered video frame, expressed in TB units.
           It's NAN if undefined.

       t   The PTS of the filtered video frame, expressed in seconds. It's NAN if undefined.

       prev_pts
           The PTS of the previously filtered video frame. It's NAN if undefined.

       prev_selected_pts
           The PTS of the last previously filtered video frame. It's NAN if undefined.

       prev_selected_t
           The PTS of the last previously selected video frame. It's NAN if undefined.

       start_pts
           The PTS of the first video frame in the video. It's NAN if undefined.

       start_t
           The time of the first video frame in the video. It's NAN if undefined.

       pict_type (video only)
           The type of the filtered frame. It can assume one of the following values:

           I
           P
           B
           S
           SI
           SP
           BI
       interlace_type (video only)
           The frame interlace type. It can assume one of the following values:

           PROGRESSIVE
               The frame is progressive (not interlaced).

           TOPFIRST
               The frame is top-field-first.

           BOTTOMFIRST
               The frame is bottom-field-first.

       consumed_sample_n (audio only)
           the number of selected samples before the current frame

       samples_n (audio only)
           the number of samples in the current frame

       sample_rate (audio only)
           the input sample rate

       key This is 1 if the filtered frame is a key-frame, 0 otherwise.

       pos the position in the file of the filtered frame, -1 if the information is not available
           (e.g. for synthetic video)

       scene (video only)
           value between 0 and 1 to indicate a new scene; a low value reflects a low probability
           for the current frame to introduce a new scene, while a higher value means the current
           frame is more likely to be one (see the example below)

       concatdec_select
           The concat demuxer can select only part of a concat input file by setting an inpoint
           and an outpoint, but the output packets may not be entirely contained in the selected
           interval. By using this variable, it is possible to skip frames generated by the
           concat demuxer which are not exactly contained in the selected interval.

           This works by comparing the frame pts against the lavf.concat.start_time and the
           lavf.concat.duration packet metadata values which are also present in the decoded
           frames.

           The concatdec_select variable is -1 if the frame pts is at least start_time and either
           the duration metadata is missing or the frame pts is less than start_time + duration,
           0 otherwise, and NaN if the start_time metadata is missing.

           That basically means that an input frame is selected if its pts is within the interval
           set by the concat demuxer.

       The default value of the select expression is "1".

       Examples

       ·   Select all frames in input:

                   select

           The example above is the same as:

                   select=1

       ·   Skip all frames:

                   select=0

       ·   Select only I-frames:

                   select='eq(pict_type\,I)'

       ·   Select one frame every 100:

                   select='not(mod(n\,100))'

       ·   Select only frames contained in the 10-20 time interval:

                   select=between(t\,10\,20)

       ·   Select only I-frames contained in the 10-20 time interval:

                   select=between(t\,10\,20)*eq(pict_type\,I)

       ·   Select frames with a minimum distance of 10 seconds:

                   select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'

       ·   Use aselect to select only audio frames with samples number > 100:

                   aselect='gt(samples_n\,100)'

       ·   Create a mosaic of the first scenes:

                   ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png

           Comparing scene against a value between 0.3 and 0.5 is generally a sane choice.

       ·   Send even and odd frames to separate outputs, and compose them:

                   select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h

       ·   Select useful frames from an ffconcat file which is using inpoints and outpoints but
           where the source files are not intra frame only.

                   ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi

   sendcmd, asendcmd
       Send commands to filters in the filtergraph.

       These filters read commands to be sent to other filters in the filtergraph.

       "sendcmd" must be inserted between two video filters, "asendcmd" must be inserted between
       two audio filters, but apart from that they act the same way.

       The specification of commands can be provided in the filter arguments with the commands
       option, or in a file specified by the filename option.

       These filters accept the following options:

       commands, c
           Set the commands to be read and sent to the other filters.

       filename, f
           Set the filename of the commands to be read and sent to the other filters.

       Commands syntax

       A commands description consists of a sequence of interval specifications, comprising a
       list of commands to be executed when a particular event related to that interval occurs.
       The occurring event is typically the current frame time entering or leaving a given time
       interval.

       An interval is specified by the following syntax:

               <START>[-<END>] <COMMANDS>;

       The time interval is specified by the START and END times.  END is optional and defaults
       to the maximum time.

       The current frame time is considered within the specified interval if it is included in
       the interval [START, END), that is when the time is greater or equal to START and is
       lesser than END.

       COMMANDS consists of a sequence of one or more command specifications, separated by ",",
       relating to that interval.  The syntax of a command specification is given by:

               [<FLAGS>] <TARGET> <COMMAND> <ARG>

       FLAGS is optional and specifies the type of events relating to the time interval which
       enable sending the specified command, and must be a non-null sequence of identifier flags
       separated by "+" or "|" and enclosed between "[" and "]".

       The following flags are recognized:

       enter
           The command is sent when the current frame timestamp enters the specified interval. In
           other words, the command is sent when the previous frame timestamp was not in the
           given interval, and the current is.

       leave
           The command is sent when the current frame timestamp leaves the specified interval. In
           other words, the command is sent when the previous frame timestamp was in the given
           interval, and the current is not.

       If FLAGS is not specified, a default value of "[enter]" is assumed.

       TARGET specifies the target of the command, usually the name of the filter class or a
       specific filter instance name.

       COMMAND specifies the name of the command for the target filter.

       ARG is optional and specifies the optional list of argument for the given COMMAND.

       Between one interval specification and another, whitespaces, or sequences of characters
       starting with "#" until the end of line, are ignored and can be used to annotate comments.

       A simplified BNF description of the commands specification syntax follows:

               <COMMAND_FLAG>  ::= "enter" | "leave"
               <COMMAND_FLAGS> ::= <COMMAND_FLAG> [(+|"|")<COMMAND_FLAG>]
               <COMMAND>       ::= ["[" <COMMAND_FLAGS> "]"] <TARGET> <COMMAND> [<ARG>]
               <COMMANDS>      ::= <COMMAND> [,<COMMANDS>]
               <INTERVAL>      ::= <START>[-<END>] <COMMANDS>
               <INTERVALS>     ::= <INTERVAL>[;<INTERVALS>]

       Examples

       ·   Specify audio tempo change at second 4:

                   asendcmd=c='4.0 atempo tempo 1.5',atempo

       ·   Specify a list of drawtext and hue commands in a file.

                   # show text in the interval 5-10
                   5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
                            [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';

                   # desaturate the image in the interval 15-20
                   15.0-20.0 [enter] hue s 0,
                             [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
                             [leave] hue s 1,
                             [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';

                   # apply an exponential saturation fade-out effect, starting from time 25
                   25 [enter] hue s exp(25-t)

           A filtergraph allowing to read and process the above command list stored in a file
           test.cmd, can be specified with:

                   sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue

   setpts, asetpts
       Change the PTS (presentation timestamp) of the input frames.

       "setpts" works on video frames, "asetpts" on audio frames.

       This filter accepts the following options:

       expr
           The expression which is evaluated for each frame to construct its timestamp.

       The expression is evaluated through the eval API and can contain the following constants:

       FRAME_RATE
           frame rate, only defined for constant frame-rate video

       PTS The presentation timestamp in input

       N   The count of the input frame for video or the number of consumed samples, not
           including the current frame for audio, starting from 0.

       NB_CONSUMED_SAMPLES
           The number of consumed samples, not including the current frame (only audio)

       NB_SAMPLES, S
           The number of samples in the current frame (only audio)

       SAMPLE_RATE, SR
           The audio sample rate.

       STARTPTS
           The PTS of the first frame.

       STARTT
           the time in seconds of the first frame

       INTERLACED
           State whether the current frame is interlaced.

       T   the time in seconds of the current frame

       POS original position in the file of the frame, or undefined if undefined for the current
           frame

       PREV_INPTS
           The previous input PTS.

       PREV_INT
           previous input time in seconds

       PREV_OUTPTS
           The previous output PTS.

       PREV_OUTT
           previous output time in seconds

       RTCTIME
           The wallclock (RTC) time in microseconds. This is deprecated, use time(0) instead.

       RTCSTART
           The wallclock (RTC) time at the start of the movie in microseconds.

       TB  The timebase of the input timestamps.

       Examples

       ·   Start counting PTS from zero

                   setpts=PTS-STARTPTS

       ·   Apply fast motion effect:

                   setpts=0.5*PTS

       ·   Apply slow motion effect:

                   setpts=2.0*PTS

       ·   Set fixed rate of 25 frames per second:

                   setpts=N/(25*TB)

       ·   Set fixed rate 25 fps with some jitter:

                   setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'

       ·   Apply an offset of 10 seconds to the input PTS:

                   setpts=PTS+10/TB

       ·   Generate timestamps from a "live source" and rebase onto the current timebase:

                   setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'

       ·   Generate timestamps by counting samples:

                   asetpts=N/SR/TB

   settb, asettb
       Set the timebase to use for the output frames timestamps.  It is mainly useful for testing
       timebase configuration.

       It accepts the following parameters:

       expr, tb
           The expression which is evaluated into the output timebase.

       The value for tb is an arithmetic expression representing a rational. The expression can
       contain the constants "AVTB" (the default timebase), "intb" (the input timebase) and "sr"
       (the sample rate, audio only). Default value is "intb".

       Examples

       ·   Set the timebase to 1/25:

                   settb=expr=1/25

       ·   Set the timebase to 1/10:

                   settb=expr=0.1

       ·   Set the timebase to 1001/1000:

                   settb=1+0.001

       ·   Set the timebase to 2*intb:

                   settb=2*intb

       ·   Set the default timebase value:

                   settb=AVTB

   showcqt
       Convert input audio to a video output representing frequency spectrum logarithmically
       using Brown-Puckette constant Q transform algorithm with direct frequency domain
       coefficient calculation (but the transform itself is not really constant Q, instead the Q
       factor is actually variable/clamped), with musical tone scale, from E0 to D#10.

       The filter accepts the following options:

       size, s
           Specify the video size for the output. It must be even. For the syntax of this option,
           check the "Video size" section in the ffmpeg-utils manual.  Default value is
           "1920x1080".

       fps, rate, r
           Set the output frame rate. Default value is 25.

       bar_h
           Set the bargraph height. It must be even. Default value is "-1" which computes the
           bargraph height automatically.

       axis_h
           Set the axis height. It must be even. Default value is "-1" which computes the axis
           height automatically.

       sono_h
           Set the sonogram height. It must be even. Default value is "-1" which computes the
           sonogram height automatically.

       fullhd
           Set the fullhd resolution. This option is deprecated, use size, s instead. Default
           value is 1.

       sono_v, volume
           Specify the sonogram volume expression. It can contain variables:

           bar_v
               the bar_v evaluated expression

           frequency, freq, f
               the frequency where it is evaluated

           timeclamp, tc
               the value of timeclamp option

           and functions:

           a_weighting(f)
               A-weighting of equal loudness

           b_weighting(f)
               B-weighting of equal loudness

           c_weighting(f)
               C-weighting of equal loudness.

           Default value is 16.

       bar_v, volume2
           Specify the bargraph volume expression. It can contain variables:

           sono_v
               the sono_v evaluated expression

           frequency, freq, f
               the frequency where it is evaluated

           timeclamp, tc
               the value of timeclamp option

           and functions:

           a_weighting(f)
               A-weighting of equal loudness

           b_weighting(f)
               B-weighting of equal loudness

           c_weighting(f)
               C-weighting of equal loudness.

           Default value is "sono_v".

       sono_g, gamma
           Specify the sonogram gamma. Lower gamma makes the spectrum more contrast, higher gamma
           makes the spectrum having more range. Default value is 3.  Acceptable range is "[1,
           7]".

       bar_g, gamma2
           Specify the bargraph gamma. Default value is 1. Acceptable range is "[1, 7]".

       bar_t
           Specify the bargraph transparency level. Lower value makes the bargraph sharper.
           Default value is 1. Acceptable range is "[0, 1]".

       timeclamp, tc
           Specify the transform timeclamp. At low frequency, there is trade-off between accuracy
           in time domain and frequency domain. If timeclamp is lower, event in time domain is
           represented more accurately (such as fast bass drum), otherwise event in frequency
           domain is represented more accurately (such as bass guitar). Acceptable range is
           "[0.002, 1]". Default value is 0.17.

       basefreq
           Specify the transform base frequency. Default value is 20.01523126408007475, which is
           frequency 50 cents below E0. Acceptable range is "[10, 100000]".

       endfreq
           Specify the transform end frequency. Default value is 20495.59681441799654, which is
           frequency 50 cents above D#10. Acceptable range is "[10, 100000]".

       coeffclamp
           This option is deprecated and ignored.

       tlength
           Specify the transform length in time domain. Use this option to control accuracy
           trade-off between time domain and frequency domain at every frequency sample.  It can
           contain variables:

           frequency, freq, f
               the frequency where it is evaluated

           timeclamp, tc
               the value of timeclamp option.

           Default value is "384*tc/(384+tc*f)".

       count
           Specify the transform count for every video frame. Default value is 6.  Acceptable
           range is "[1, 30]".

       fcount
           Specify the transform count for every single pixel. Default value is 0, which makes it
           computed automatically. Acceptable range is "[0, 10]".

       fontfile
           Specify font file for use with freetype to draw the axis. If not specified, use
           embedded font. Note that drawing with font file or embedded font is not implemented
           with custom basefreq and endfreq, use axisfile option instead.

       font
           Specify fontconfig pattern. This has lower priority than fontfile.  The : in the
           pattern may be replaced by | to avoid unnecessary escaping.

       fontcolor
           Specify font color expression. This is arithmetic expression that should return
           integer value 0xRRGGBB. It can contain variables:

           frequency, freq, f
               the frequency where it is evaluated

           timeclamp, tc
               the value of timeclamp option

           and functions:

           midi(f)
               midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)

           r(x), g(x), b(x)
               red, green, and blue value of intensity x.

           Default value is "st(0, (midi(f)-59.5)/12); st(1, if(between(ld(0),0,1),
           0.5-0.5*cos(2*PI*ld(0)), 0)); r(1-ld(1)) + b(ld(1))".

       axisfile
           Specify image file to draw the axis. This option override fontfile and fontcolor
           option.

       axis, text
           Enable/disable drawing text to the axis. If it is set to 0, drawing to the axis is
           disabled, ignoring fontfile and axisfile option.  Default value is 1.

       csp Set colorspace. The accepted values are:

           unspecified
               Unspecified (default)

           bt709
               BT.709

           fcc FCC

           bt470bg
               BT.470BG or BT.601-6 625

           smpte170m
               SMPTE-170M or BT.601-6 525

           smpte240m
               SMPTE-240M

           bt2020ncl
               BT.2020 with non-constant luminance

       cscheme
           Set spectrogram color scheme. This is list of floating point values with format
           "left_r|left_g|left_b|right_r|right_g|right_b".  The default is "1|0.5|0|0|0.5|1".

       Examples

       ·   Playing audio while showing the spectrum:

                   ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'

       ·   Same as above, but with frame rate 30 fps:

                   ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'

       ·   Playing at 1280x720:

                   ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=s=1280x720:count=4 [out0]'

       ·   Disable sonogram display:

                   sono_h=0

       ·   A1 and its harmonics: A1, A2, (near)E3, A3:

                   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),
                                    asplit[a][out1]; [a] showcqt [out0]'

       ·   Same as above, but with more accuracy in frequency domain:

                   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),
                                    asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'

       ·   Custom volume:

                   bar_v=10:sono_v=bar_v*a_weighting(f)

       ·   Custom gamma, now spectrum is linear to the amplitude.

                   bar_g=2:sono_g=2

       ·   Custom tlength equation:

                   tc=0.33:tlength='st(0,0.17); 384*tc / (384 / ld(0) + tc*f /(1-ld(0))) + 384*tc / (tc*f / ld(0) + 384 /(1-ld(0)))'

       ·   Custom fontcolor and fontfile, C-note is colored green, others are colored blue:

                   fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf

       ·   Custom font using fontconfig:

                   font='Courier New,Monospace,mono|bold'

       ·   Custom frequency range with custom axis using image file:

                   axisfile=myaxis.png:basefreq=40:endfreq=10000

   showfreqs
       Convert input audio to video output representing the audio power spectrum.  Audio
       amplitude is on Y-axis while frequency is on X-axis.

       The filter accepts the following options:

       size, s
           Specify size of video. For the syntax of this option, check the "Video size" section
           in the ffmpeg-utils manual.  Default is "1024x512".

       mode
           Set display mode.  This set how each frequency bin will be represented.

           It accepts the following values:

           line
           bar
           dot

           Default is "bar".

       ascale
           Set amplitude scale.

           It accepts the following values:

           lin Linear scale.

           sqrt
               Square root scale.

           cbrt
               Cubic root scale.

           log Logarithmic scale.

           Default is "log".

       fscale
           Set frequency scale.

           It accepts the following values:

           lin Linear scale.

           log Logarithmic scale.

           rlog
               Reverse logarithmic scale.

           Default is "lin".

       win_size
           Set window size.

           It accepts the following values:

           w16
           w32
           w64
           w128
           w256
           w512
           w1024
           w2048
           w4096
           w8192
           w16384
           w32768
           w65536

           Default is "w2048"

       win_func
           Set windowing function.

           It accepts the following values:

           rect
           bartlett
           hanning
           hamming
           blackman
           welch
           flattop
           bharris
           bnuttall
           bhann
           sine
           nuttall
           lanczos
           gauss
           tukey
           dolph
           cauchy
           parzen
           poisson

           Default is "hanning".

       overlap
           Set window overlap. In range "[0, 1]". Default is 1, which means optimal overlap for
           selected window function will be picked.

       averaging
           Set time averaging. Setting this to 0 will display current maximal peaks.  Default is
           1, which means time averaging is disabled.

       colors
           Specify list of colors separated by space or by '|' which will be used to draw channel
           frequencies. Unrecognized or missing colors will be replaced by white color.

       cmode
           Set channel display mode.

           It accepts the following values:

           combined
           separate

           Default is "combined".

       minamp
           Set minimum amplitude used in "log" amplitude scaler.

   showspectrum
       Convert input audio to a video output, representing the audio frequency spectrum.

       The filter accepts the following options:

       size, s
           Specify the video size for the output. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  Default value is "640x512".

       slide
           Specify how the spectrum should slide along the window.

           It accepts the following values:

           replace
               the samples start again on the left when they reach the right

           scroll
               the samples scroll from right to left

           fullframe
               frames are only produced when the samples reach the right

           rscroll
               the samples scroll from left to right

           Default value is "replace".

       mode
           Specify display mode.

           It accepts the following values:

           combined
               all channels are displayed in the same row

           separate
               all channels are displayed in separate rows

           Default value is combined.

       color
           Specify display color mode.

           It accepts the following values:

           channel
               each channel is displayed in a separate color

           intensity
               each channel is displayed using the same color scheme

           rainbow
               each channel is displayed using the rainbow color scheme

           moreland
               each channel is displayed using the moreland color scheme

           nebulae
               each channel is displayed using the nebulae color scheme

           fire
               each channel is displayed using the fire color scheme

           fiery
               each channel is displayed using the fiery color scheme

           fruit
               each channel is displayed using the fruit color scheme

           cool
               each channel is displayed using the cool color scheme

           Default value is channel.

       scale
           Specify scale used for calculating intensity color values.

           It accepts the following values:

           lin linear

           sqrt
               square root, default

           cbrt
               cubic root

           log logarithmic

           4thrt
               4th root

           5thrt
               5th root

           Default value is sqrt.

       saturation
           Set saturation modifier for displayed colors. Negative values provide alternative
           color scheme. 0 is no saturation at all.  Saturation must be in [-10.0, 10.0] range.
           Default value is 1.

       win_func
           Set window function.

           It accepts the following values:

           rect
           bartlett
           hann
           hanning
           hamming
           blackman
           welch
           flattop
           bharris
           bnuttall
           bhann
           sine
           nuttall
           lanczos
           gauss
           tukey
           dolph
           cauchy
           parzen
           poisson

           Default value is "hann".

       orientation
           Set orientation of time vs frequency axis. Can be "vertical" or "horizontal". Default
           is "vertical".

       overlap
           Set ratio of overlap window. Default value is 0.  When value is 1 overlap is set to
           recommended size for specific window function currently used.

       gain
           Set scale gain for calculating intensity color values.  Default value is 1.

       data
           Set which data to display. Can be "magnitude", default or "phase".

       rotation
           Set color rotation, must be in [-1.0, 1.0] range.  Default value is 0.

       The usage is very similar to the showwaves filter; see the examples in that section.

       Examples

       ·   Large window with logarithmic color scaling:

                   showspectrum=s=1280x480:scale=log

       ·   Complete example for a colored and sliding spectrum per channel using ffplay:

                   ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
                                [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'

   showspectrumpic
       Convert input audio to a single video frame, representing the audio frequency spectrum.

       The filter accepts the following options:

       size, s
           Specify the video size for the output. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  Default value is "4096x2048".

       mode
           Specify display mode.

           It accepts the following values:

           combined
               all channels are displayed in the same row

           separate
               all channels are displayed in separate rows

           Default value is combined.

       color
           Specify display color mode.

           It accepts the following values:

           channel
               each channel is displayed in a separate color

           intensity
               each channel is displayed using the same color scheme

           rainbow
               each channel is displayed using the rainbow color scheme

           moreland
               each channel is displayed using the moreland color scheme

           nebulae
               each channel is displayed using the nebulae color scheme

           fire
               each channel is displayed using the fire color scheme

           fiery
               each channel is displayed using the fiery color scheme

           fruit
               each channel is displayed using the fruit color scheme

           cool
               each channel is displayed using the cool color scheme

           Default value is intensity.

       scale
           Specify scale used for calculating intensity color values.

           It accepts the following values:

           lin linear

           sqrt
               square root, default

           cbrt
               cubic root

           log logarithmic

           4thrt
               4th root

           5thrt
               5th root

           Default value is log.

       saturation
           Set saturation modifier for displayed colors. Negative values provide alternative
           color scheme. 0 is no saturation at all.  Saturation must be in [-10.0, 10.0] range.
           Default value is 1.

       win_func
           Set window function.

           It accepts the following values:

           rect
           bartlett
           hann
           hanning
           hamming
           blackman
           welch
           flattop
           bharris
           bnuttall
           bhann
           sine
           nuttall
           lanczos
           gauss
           tukey
           dolph
           cauchy
           parzen
           poisson

           Default value is "hann".

       orientation
           Set orientation of time vs frequency axis. Can be "vertical" or "horizontal". Default
           is "vertical".

       gain
           Set scale gain for calculating intensity color values.  Default value is 1.

       legend
           Draw time and frequency axes and legends. Default is enabled.

       rotation
           Set color rotation, must be in [-1.0, 1.0] range.  Default value is 0.

       Examples

       ·   Extract an audio spectrogram of a whole audio track in a 1024x1024 picture using
           ffmpeg:

                   ffmpeg -i audio.flac -lavfi showspectrumpic=s=1024x1024 spectrogram.png

   showvolume
       Convert input audio volume to a video output.

       The filter accepts the following options:

       rate, r
           Set video rate.

       b   Set border width, allowed range is [0, 5]. Default is 1.

       w   Set channel width, allowed range is [80, 8192]. Default is 400.

       h   Set channel height, allowed range is [1, 900]. Default is 20.

       f   Set fade, allowed range is [0.001, 1]. Default is 0.95.

       c   Set volume color expression.

           The expression can use the following variables:

           VOLUME
               Current max volume of channel in dB.

           PEAK
               Current peak.

           CHANNEL
               Current channel number, starting from 0.

       t   If set, displays channel names. Default is enabled.

       v   If set, displays volume values. Default is enabled.

       o   Set orientation, can be "horizontal" or "vertical", default is "horizontal".

       s   Set step size, allowed range s [0, 5]. Default is 0, which means step is disabled.

   showwaves
       Convert input audio to a video output, representing the samples waves.

       The filter accepts the following options:

       size, s
           Specify the video size for the output. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  Default value is "600x240".

       mode
           Set display mode.

           Available values are:

           point
               Draw a point for each sample.

           line
               Draw a vertical line for each sample.

           p2p Draw a point for each sample and a line between them.

           cline
               Draw a centered vertical line for each sample.

           Default value is "point".

       n   Set the number of samples which are printed on the same column. A larger value will
           decrease the frame rate. Must be a positive integer. This option can be set only if
           the value for rate is not explicitly specified.

       rate, r
           Set the (approximate) output frame rate. This is done by setting the option n. Default
           value is "25".

       split_channels
           Set if channels should be drawn separately or overlap. Default value is 0.

       colors
           Set colors separated by '|' which are going to be used for drawing of each channel.

       scale
           Set amplitude scale.

           Available values are:

           lin Linear.

           log Logarithmic.

           sqrt
               Square root.

           cbrt
               Cubic root.

           Default is linear.

       Examples

       ·   Output the input file audio and the corresponding video representation at the same
           time:

                   amovie=a.mp3,asplit[out0],showwaves[out1]

       ·   Create a synthetic signal and show it with showwaves, forcing a frame rate of 30
           frames per second:

                   aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]

   showwavespic
       Convert input audio to a single video frame, representing the samples waves.

       The filter accepts the following options:

       size, s
           Specify the video size for the output. For the syntax of this option, check the "Video
           size" section in the ffmpeg-utils manual.  Default value is "600x240".

       split_channels
           Set if channels should be drawn separately or overlap. Default value is 0.

       colors
           Set colors separated by '|' which are going to be used for drawing of each channel.

       scale
           Set amplitude scale.

           Available values are:

           lin Linear.

           log Logarithmic.

           sqrt
               Square root.

           cbrt
               Cubic root.

           Default is linear.

       Examples

       ·   Extract a channel split representation of the wave form of a whole audio track in a
           1024x800 picture using ffmpeg:

                   ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png

   sidedata, asidedata
       Delete frame side data, or select frames based on it.

       This filter accepts the following options:

       mode
           Set mode of operation of the filter.

           Can be one of the following:

           select
               Select every frame with side data of "type".

           delete
               Delete side data of "type". If "type" is not set, delete all side data in the
               frame.

       type
           Set side data type used with all modes. Must be set for "select" mode. For the list of
           frame side data types, refer to the "AVFrameSideDataType" enum in libavutil/frame.h.
           For example, to choose "AV_FRAME_DATA_PANSCAN" side data, you must specify "PANSCAN".

   spectrumsynth
       Sythesize audio from 2 input video spectrums, first input stream represents magnitude
       across time and second represents phase across time.  The filter will transform from
       frequency domain as displayed in videos back to time domain as presented in audio output.

       This filter is primarily created for reversing processed showspectrum filter outputs, but
       can synthesize sound from other spectrograms too.  But in such case results are going to
       be poor if the phase data is not available, because in such cases phase data need to be
       recreated, usually its just recreated from random noise.  For best results use gray only
       output ("channel" color mode in showspectrum filter) and "log" scale for magnitude video
       and "lin" scale for phase video. To produce phase, for 2nd video, use "data" option.
       Inputs videos should generally use "fullframe" slide mode as that saves resources needed
       for decoding video.

       The filter accepts the following options:

       sample_rate
           Specify sample rate of output audio, the sample rate of audio from which spectrum was
           generated may differ.

       channels
           Set number of channels represented in input video spectrums.

       scale
           Set scale which was used when generating magnitude input spectrum.  Can be "lin" or
           "log". Default is "log".

       slide
           Set slide which was used when generating inputs spectrums.  Can be "replace",
           "scroll", "fullframe" or "rscroll".  Default is "fullframe".

       win_func
           Set window function used for resynthesis.

       overlap
           Set window overlap. In range "[0, 1]". Default is 1, which means optimal overlap for
           selected window function will be picked.

       orientation
           Set orientation of input videos. Can be "vertical" or "horizontal".  Default is
           "vertical".

       Examples

       ·   First create magnitude and phase videos from audio, assuming audio is stereo with
           44100 sample rate, then resynthesize videos back to audio with spectrumsynth:

                   ffmpeg -i input.flac -lavfi showspectrum=mode=separate:scale=log:overlap=0.875:color=channel:slide=fullframe:data=magnitude -an -c:v rawvideo magnitude.nut
                   ffmpeg -i input.flac -lavfi showspectrum=mode=separate:scale=lin:overlap=0.875:color=channel:slide=fullframe:data=phase -an -c:v rawvideo phase.nut
                   ffmpeg -i magnitude.nut -i phase.nut -lavfi spectrumsynth=channels=2:sample_rate=44100:win_func=hann:overlap=0.875:slide=fullframe output.flac

   split, asplit
       Split input into several identical outputs.

       "asplit" works with audio input, "split" with video.

       The filter accepts a single parameter which specifies the number of outputs. If
       unspecified, it defaults to 2.

       Examples

       ·   Create two separate outputs from the same input:

                   [in] split [out0][out1]

       ·   To create 3 or more outputs, you need to specify the number of outputs, like in:

                   [in] asplit=3 [out0][out1][out2]

       ·   Create two separate outputs from the same input, one cropped and one padded:

                   [in] split [splitout1][splitout2];
                   [splitout1] crop=100:100:0:0    [cropout];
                   [splitout2] pad=200:200:100:100 [padout];

       ·   Create 5 copies of the input audio with ffmpeg:

                   ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT

   zmq, azmq
       Receive commands sent through a libzmq client, and forward them to filters in the
       filtergraph.

       "zmq" and "azmq" work as a pass-through filters. "zmq" must be inserted between two video
       filters, "azmq" between two audio filters.

       To enable these filters you need to install the libzmq library and headers and configure
       FFmpeg with "--enable-libzmq".

       For more information about libzmq see: <http://www.zeromq.org/>

       The "zmq" and "azmq" filters work as a libzmq server, which receives messages sent through
       a network interface defined by the bind_address option.

       The received message must be in the form:

               <TARGET> <COMMAND> [<ARG>]

       TARGET specifies the target of the command, usually the name of the filter class or a
       specific filter instance name.

       COMMAND specifies the name of the command for the target filter.

       ARG is optional and specifies the optional argument list for the given COMMAND.

       Upon reception, the message is processed and the corresponding command is injected into
       the filtergraph. Depending on the result, the filter will send a reply to the client,
       adopting the format:

               <ERROR_CODE> <ERROR_REASON>
               <MESSAGE>

       MESSAGE is optional.

       Examples

       Look at tools/zmqsend for an example of a zmq client which can be used to send commands
       processed by these filters.

       Consider the following filtergraph generated by ffplay

               ffplay -dumpgraph 1 -f lavfi "
               color=s=100x100:c=red  [l];
               color=s=100x100:c=blue [r];
               nullsrc=s=200x100, zmq [bg];
               [bg][l]   overlay      [bg+l];
               [bg+l][r] overlay=x=100 "

       To change the color of the left side of the video, the following command can be used:

               echo Parsed_color_0 c yellow | tools/zmqsend

       To change the right side:

               echo Parsed_color_1 c pink | tools/zmqsend

MULTIMEDIA SOURCES

       Below is a description of the currently available multimedia sources.

   amovie
       This is the same as movie source, except it selects an audio stream by default.

   movie
       Read audio and/or video stream(s) from a movie container.

       It accepts the following parameters:

       filename
           The name of the resource to read (not necessarily a file; it can also be a device or a
           stream accessed through some protocol).

       format_name, f
           Specifies the format assumed for the movie to read, and can be either the name of a
           container or an input device. If not specified, the format is guessed from movie_name
           or by probing.

       seek_point, sp
           Specifies the seek point in seconds. The frames will be output starting from this seek
           point. The parameter is evaluated with "av_strtod", so the numerical value may be
           suffixed by an IS postfix. The default value is "0".

       streams, s
           Specifies the streams to read. Several streams can be specified, separated by "+". The
           source will then have as many outputs, in the same order. The syntax is explained in
           the ``Stream specifiers'' section in the ffmpeg manual. Two special names, "dv" and
           "da" specify respectively the default (best suited) video and audio stream. Default is
           "dv", or "da" if the filter is called as "amovie".

       stream_index, si
           Specifies the index of the video stream to read. If the value is -1, the most suitable
           video stream will be automatically selected. The default value is "-1". Deprecated. If
           the filter is called "amovie", it will select audio instead of video.

       loop
           Specifies how many times to read the stream in sequence.  If the value is 0, the
           stream will be looped infinitely.  Default value is "1".

           Note that when the movie is looped the source timestamps are not changed, so it will
           generate non monotonically increasing timestamps.

       discontinuity
           Specifies the time difference between frames above which the point is considered a
           timestamp discontinuity which is removed by adjusting the later timestamps.

       It allows overlaying a second video on top of the main input of a filtergraph, as shown in
       this graph:

               input -----------> deltapts0 --> overlay --> output
                                                   ^
                                                   |
               movie --> scale--> deltapts1 -------+

       Examples

       ·   Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it on top of the
           input labelled "in":

                   movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
                   [in] setpts=PTS-STARTPTS [main];
                   [main][over] overlay=16:16 [out]

       ·   Read from a video4linux2 device, and overlay it on top of the input labelled "in":

                   movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
                   [in] setpts=PTS-STARTPTS [main];
                   [main][over] overlay=16:16 [out]

       ·   Read the first video stream and the audio stream with id 0x81 from dvd.vob; the video
           is connected to the pad named "video" and the audio is connected to the pad named
           "audio":

                   movie=dvd.vob:s=v:0+#0x81 [video] [audio]

       Commands

       Both movie and amovie support the following commands:

       seek
           Perform seek using "av_seek_frame".  The syntax is: seek stream_index|timestamp|flags

           ·   stream_index: If stream_index is -1, a default stream is selected, and timestamp
               is automatically converted from AV_TIME_BASE units to the stream specific
               time_base.

           ·   timestamp: Timestamp in AVStream.time_base units or, if no stream is specified, in
               AV_TIME_BASE units.

           ·   flags: Flags which select direction and seeking mode.

       get_duration
           Get movie duration in AV_TIME_BASE units.

SEE ALSO

       ffmpeg(1), ffplay(1), ffprobe(1), ffserver(1), libavfilter(3)

AUTHORS

       The FFmpeg developers.

       For details about the authorship, see the Git history of the project
       (git://source.ffmpeg.org/ffmpeg), e.g. by typing the command git log in the FFmpeg source
       directory, or browsing the online repository at <http://source.ffmpeg.org>.

       Maintainers for the specific components are listed in the file MAINTAINERS in the source
       code tree.

                                                                                FFMPEG-FILTERS(1)