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.

     input --> split ---------------------> overlay --> output
                 |                             ^
                 |                             |
                 +-----> crop --> vflip -------+

This filtergraph splits the input stream in two streams, 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 in output the top half of the video is mirrored onto the bottom half.

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.

graph2dot
*********

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 the 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", a filter with no output pads is called a "sink".

Filtergraph syntax
==================

A filtergraph can be represented using a textual representation, which is recognized by the -filter/-vf and -filter_complex options in ffmpeg and -vf in ffplay, and by the avfilter_graph_parse()/avfilter_graph_parse2() 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 the following 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 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 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.

Follows a BNF description for the filtergraph syntax:

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

Notes on filtergraph escaping
=============================

Some filter arguments require the use of special characters, typically : to separate key=value pairs in a named options list. In this case the user should perform a first level escaping when specifying the filter arguments. For example, consider the following literal string to be embedded in the drawtext filter arguments:

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

Since : is special for the filter arguments syntax, it needs to be escaped, so you get:

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

A second level of escaping is required when embedding the filter arguments 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

Finally an additional level of escaping may be 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"

Sometimes, it might be more convenient to employ quoting in place of escaping. For example the string:

     Caesar: tu quoque, Brute, fili mi

Can be quoted in the filter arguments as:

     text='Caesar: tu quoque, Brute, fili mi'

And finally inserted in a filtergraph like:

     drawtext=text=\'Caesar: tu quoque\, Brute\, fili mi\'

See the ``Quoting and escaping'' section in the ffmpeg-utils manual for more information about the escaping and quoting rules adopted by FFmpeg.

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

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

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.

aconvert
========

Convert the input audio format to the specified formats.

This filter is deprecated. Use aformat instead.

The filter accepts a string of the form: "SAMPLE_FORMAT:CHANNEL_LAYOUT".

SAMPLE_FORMAT specifies the sample format, and can be a string or the corresponding numeric value defined in libavutil/samplefmt.h. Use 'p' suffix for a planar sample format.

CHANNEL_LAYOUT specifies the channel layout, and can be a string or the corresponding number value defined in libavutil/channel_layout.h.

The special parameter "auto", signifies that the filter will automatically select the output format depending on the output filter.

Examples
--------

  * Convert input to float, planar, stereo:

          aconvert=fltp:stereo

  * Convert input to unsigned 8-bit, automatically select out channel layout:

          aconvert=u8:auto

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 time for starting to apply the fade effect. Default is 0. The accepted syntax is:

          [-]HH[:MM[:SS[.m...]]]
          [-]S+[.m...]

     See also the function av_parse_time(). If set this option is used instead of START_SAMPLE one.

duration, d
     Specify the duration for which the fade effect has to last. Default is 0. The accepted syntax is:

          [-]HH[:MM[:SS[.m...]]]
          [-]S+[.m...]

     See also the function av_parse_time(). 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. If set this option is used instead of NB_SAMPLES one.

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

     par
          select inverted parabola

     qua
          select quadratic

     cub
          select cubic

     squ
          select square root

     cbr
          select cubic root

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

aformat
=======

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

The filter accepts the following named 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.

If a parameter is omitted, all values are allowed.

For example to force the output to either unsigned 8-bit or signed 16-bit stereo:

     aformat=sample_fmts=u8|s16:channel_layouts=stereo

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.

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.

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.

The filter accepts the following named parameters:

inputs
     Number of inputs. If unspecified, it defaults to 2.

duration
     How to determine the end-of-stream.

     longest
          Duration of longest input. (default)

     shortest
          Duration of shortest input.

     first
          Duration of first input.

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

anull
=====

Pass the audio source unchanged to the output.

apad
====

Pad the end of a audio stream with silence, this can be used together with -shortest to extend audio streams to the same length as the video stream.

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

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 ffmpeg-resampler 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

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 signal 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.

A description of each shown parameter follows:

n
     sequential number of the input frame, starting from 0

pts
     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
     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
     sample format

chlayout
     channel layout

rate
     sample rate for the audio frame

nb_samples
     number of samples (per channel) in the frame

checksum
     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.

The filter accepts the following option:

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

A description of each shown parameter follows:

DC offset
     Mean amplitude displacement from zero.

Min level
     Minimal sample level.

Max level
     Maximal sample level.

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.

astreamsync
===========

Forward two audio streams and control the order the buffers are forwarded.

The filter accepts the following options:

expr, e
     Set the expression deciding which stream should be forwarded next: if the result is negative, the first stream is forwarded; if the result is positive or zero, the second stream is forwarded. It can use the following variables:

     b1 b2
          number of buffers forwarded so far on each stream

     s1 s2
          number of samples forwarded so far on each stream

     t1 t2
          current timestamp of each stream

     The default value is t1-t2, which means to always forward the stream that has a smaller timestamp.

Examples
--------

Stress-test amerge by randomly sending buffers on the wrong input, while avoiding too much of a desynchronization:

     amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
     [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
     [a2] [b2] amerge

asyncts
=======

Synchronize audio data with timestamps by squeezing/stretching it and/or dropping samples/adding silence when needed.

This filter is not built by default, please use aresample to do squeezing/stretching.

The filter accepts the following named parameters:

compensate
     Enable stretching/squeezing the data to make it match the timestamps. Disabled by default. When disabled, time gaps are covered with silence.

min_delta
     Minimum difference between timestamps and audio data (in seconds) to trigger adding/dropping samples. Default value is 0.1. If you get non-perfect sync with this filter, try setting this parameter to 0.

max_comp
     Maximum compensation in samples per second. Relevant only with compensate=1. Default value 500.

first_pts
     Assume the first pts should be this value. The time base is 1 / sample rate. 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 silence if an audio stream starts after the video stream or to trim any samples with a negative pts due to encoder delay.

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.

This filter accepts the following options:

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

end
     Timestamp (in seconds) 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
     Maximum duration of the output in seconds.

start_sample
     Number of the first sample that should be passed to output.

end_sample
     Number of the first sample that should be dropped.

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 that 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.

channelmap
==========

Remap input channels to new locations.

This filter accepts the following named parameters:

channel_layout
     Channel layout of the output stream.

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.

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

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:channel_layout=5.1' out.wav

channelsplit
============

Split each channel in input audio stream into a separate output stream.

This filter accepts the following named parameters:

channel_layout
     Channel layout of the input stream. 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.

To 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

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.

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.

The filter accepts the following named parameters:

inputs
     Number of input streams. Defaults to 2.

channel_layout
     Desired output channel layout. 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 those 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.

E.g. to join 3 inputs (with properly set channel layouts)

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

To 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

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 remap efficiently 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=1: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"

resample
========

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

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 -

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.

volume
======

Adjust the input audio volume.

The filter accepts the following options:

volume
     Expresses how the audio volume will be increased or decreased.

     Output values are clipped to the maximum value.

     The output audio volume is given by the relation:

          OUTPUT_VOLUME = VOLUME * INPUT_VOLUME

     Default value for VOLUME is 1.0.

precision
     Set the mathematical precision.

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

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

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

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

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

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 an 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 named parameters:

time_base
     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 corresponging 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.

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 function av_parse_time() for the accepted format. 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
========

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

     Specify 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
     Specify 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 synthetize 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/

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, s
     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, 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

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 to be employed 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.

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.

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.

The filter accepts the following options:

amount
     Set the percentage of the pixels that have to be below the threshold, defaults to 98.

threshold, thresh
     Set the threshold below which a pixel value is considered black, defaults to 32.

blend
=====

Blend two video frames into each other.

It takes two input streams and outputs one stream, the first input is the "top" layer and second input is "bottom" layer. Output terminates when shortest input terminates.

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

     and

     average

     burn

     darken

     difference

     divide

     dodge

     exclusion

     hardlight

     lighten

     multiply

     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).

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)'

boxblur
=======

Apply boxblur algorithm to the input video.

The filter accepts the following options:

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
          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 luma, chroma, and alpha radius set to 2:

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

  * Set luma radius to 2, alpha and chroma radius to 0:

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

  * Set luma and chroma radius 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

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

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

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

     bt601
          BT.601

     smpte240m
          SMPTE-240M

     fcc
          FCC

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

     colormatrix=bt601:smpte240m

copy
====

Copy the input source unchanged to the output. Mainly useful for testing purposes.

crop
====

Crop the input video to given dimensions.

The filter accepts the following options:

w, out_w
     Width of the output video. It defaults to iw. This expression is evaluated only once during the filter configuration.

h, out_h
     Height of the output video. It defaults to ih. This expression is evaluated only once during the filter configuration.

x
     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
     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.

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
     same as IN_W and IN_H

out_w

out_h
     the output (cropped) width and height

ow

oh
     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 input frame, starting from 0

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

t
     timestamp expressed in seconds, 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

  * Appply 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)

cropdetect
==========

Auto-detect crop size.

Calculate necessary cropping parameters and prints the recommended parameters through the logging system. The detected dimensions correspond to the non-black area of the input video.

The filter accepts the following options:

limit
     Set higher black value threshold, which can be optionally specified from nothing (0) to everything (255). An intensity value greater to the set value is considered non-black. Default value is 24.

round
     Set the value for which the width/height should be divisible by. 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. Default value is 16.

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 return 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.

If there is no key point defined in x=0, the filter will automatically insert a (0;0) point. In the same way, if there is no key point defined in x=1, the filter will automatically insert a (1;1) point.

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 (.asv) to import the settings from.

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='0.5/0.58'

  * Vintage effect:

          curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':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.asv':green='0.45/0.53'

dctdnoiz
========

Denoise frames using 2D DCT (frequency domain filtering).

This filter is not designed for real time and can be extremely slow.

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. Each block is of size 16x16. 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 allow to process the whole input width or height, a warning will be displayed and according borders won't be denoised.

     Default value is 15.

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.

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)'

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.

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).

This filter accepts the following options:

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 4.

show
     When set to 1, a green rectangle is drawn on the screen to simplify finding the right X, Y, W, H parameters, and BAND is set to 4. The default value is 0.

Examples
--------

  * Set a rectangle covering the area with top left corner coordinates 0,0 and size 100x77, setting 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.

drawbox
=======

Draw a colored box on the input image.

This filter accepts the following options:

x

y
     The expressions which specify the top left corner coordinates of the box. Default 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. Default to 0.

color, c
     Specify the color of the box to write, it can be the name of a color (case insensitive match) or a 0xRRGGBB[AA] sequence. 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.

This filter accepts the following options:

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, it can be the name of a color (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special value invert is used, the grid color is the same as the video with inverted luma. Note that you can append opacity value (in range of 0.0 - 1.0) to color name after @ sign.

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 text string or text from specified file on top of video using the libfreetype library.

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

Syntax
------

The description of the accepted parameters follows.

box
     Used to draw a box around text using background color. Value should be either 1 (enable) or 0 (disable). The default value of BOX is 0.

boxcolor
     The color to be used for drawing box around text. Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format (e.g. "0xff00ff"), possibly followed by an alpha specifier. The default value of BOXCOLOR is "white".

draw
     Set an expression which specifies if the text should be drawn. If the expression evaluates to 0, the text is not drawn. This is useful for specifying that the text should be drawn only when specific conditions are met.

     Default value is "1".

     See below for the list of accepted constants and functions.

expansion
     Select how the TEXT is expanded. Can be either none, strftime (deprecated) or normal (default). See the Text expansion section below for details.

fix_bounds
     If true, check and fix text coords to avoid clipping.

fontcolor
     The color to be used for drawing fonts. Either a string (e.g. "red") or in 0xRRGGBB[AA] format (e.g. "0xff000033"), possibly followed by an alpha specifier. The default value of FONTCOLOR is "black".

fontfile
     The font file to be used for drawing text. Path must be included. This parameter is mandatory.

fontsize
     The font size to be used for drawing text. The default value of FONTSIZE is 16.

ft_load_flags
     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 "render".

     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.  It can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA] form (e.g. "0xff00ff"), possibly followed by an alpha specifier. 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. 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).

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
     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.

If libavfilter was built with --enable-fontconfig, then fontfile can be a fontconfig pattern or omitted.

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.

Sequence 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.

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.

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, in seconds, with microsecond accuracy.

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-line_h)/2"

  * 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:draw=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}'

For more information about libfreetype, check: http://www.freetype.org/.

For more information about fontconfig, check: http://freedesktop.org/software/fontconfig/fontconfig-user.html.

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 choosen 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.

Example:

     edgedetect=low=0.1:high=0.4

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

fade
====

Apply fade-in/out effect to input video.

This filter accepts the following options:

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

start_frame, s
     Specify the number of the start frame for starting to apply the fade effect. Default is 0.

nb_frames, n
     The number of frames 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 completely black. 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 completely black. If both duration and nb_frames are specified, duration is used. Default is 0.

Examples
--------

  * Fade in first 30 frames of video:

          fade=in:0:30

     The command above is equivalent to:

          fade=t=in:s=0:n=30

  * Fade out last 45 frames of a 200-frame video:

          fade=out:155:45
          fade=type=out:start_frame=155:nb_frames=45

  * Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:

          fade=in:0:25, fade=out:975:25

  * Make first 5 frames black, then fade in from frame 5-24:

          fade=in:5:20

  * Fade in alpha over first 25 frames of video:

          fade=in:0:25:alpha=1

  * Make first 5.5 seconds black, then fade in for 0.5 seconds:

          fade=t=in:st=5.5:d=0.5

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).

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 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.

This filter accepts the following options:

order
     Output field order. Valid values are TFF for top field first or BFF for bottom field first.

Default value is tff.

Transformation is achieved 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.

This filter 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
====

Buffer input images and send them when they are requested.

This filter is mainly useful when auto-inserted by the libavfilter framework.

The filter does not take parameters.

format
======

Convert the input video to one of the specified pixel formats. Libavfilter will try to pick one that is supported for the input to the next filter.

This filter accepts the following parameters:

pix_fmts
     A '|'-separated list of pixel format names, for example "pix_fmts=yuv420p|monow|rgb24".

Examples
--------

  * Convert the input video to the format YUV420P

          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.

This filter accepts the following named parameters:

fps
     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.

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

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 compilation of this filter you need to install the frei0r header and configure FFmpeg with --enable-frei0r.

This filter accepts the following options:

filter_name
     The name to the frei0r effect to load. If the environment variable FREI0R_PATH is defined, the frei0r effect is searched in each one of the directories specified by the colon separated list in FREIOR_PATH, otherwise in the standard frei0r paths, which are 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 (whose values are specified with "y" and "n"), a double, a color (specified by the syntax R/G/B, R, G, and B being float numbers from 0.0 to 1.0) or by an av_parse_color() color description), a position (specified by the syntax X/Y, X and Y being float numbers) and a string.

The number and kind of parameters depend on the loaded effect. If an effect parameter is not specified the default value is set.

Examples
--------

  * Apply the distort0r effect, set the first two double parameters:

          frei0r=filter_name=distort0r:filter_params=0.5|0.01

  * Apply the colordistance effect, take a color as first parameter:

          frei0r=colordistance:0.2/0.3/0.4
          frei0r=colordistance:violet
          frei0r=colordistance:0x112233

  * Apply the perspective effect, specify 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

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)'

gradfun
=======

Fix the banding artifacts that are sometimes introduced into nearly flat regions by truncation to 8bit color depth. Interpolate the gradients that should go where the bands are, and dither them.

This filter 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.

This filter accepts the following options:

strength
     The maximum amount by which the filter will change any one pixel. Also the threshold for detecting nearly flat regions. Acceptable values range from .51 to 64, 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, 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 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 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 distribution of color components in an image.

The filter accepts the following options:

mode
     Set histogram mode.

     It accepts the following values:

     levels
          standard histogram that display color components distribution in an image. Displays color graph for each color component. Shows distribution of the Y, U, V, A or G, B, R components, depending on input format, in current frame. Bellow each graph is color component scale meter.

     color
          chroma values in vectorscope, if brighter more such chroma values are distributed in an image. Displays chroma values (U/V color placement) in two dimensional graph (which is called a vectorscope). It can be used to read of the hue and saturation of the current frame. At a same time it is a histogram. The whiter a pixel in the vectorscope, the more pixels of the input frame correspond to that pixel (that is the more pixels have this chroma value). The V component is displayed on the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost side being V = 255. The U component is displayed on the vertical (Y) axis, with the top representing U = 0 and the bottom representing U = 255.

          The position of a white pixel in the graph corresponds to the chroma value of a pixel of the input clip. So the graph can be used to read of the hue (color flavor) and the saturation (the dominance of the hue in the color). As the hue of a color changes, it moves around the square. At the center of the square, the saturation is zero, which means that the corresponding pixel has no color. If you increase the amount of a specific color, while leaving the other colors unchanged, the saturation increases, and you move towards the edge of the square.

     color2
          chroma values in vectorscope, similar as color but actual chroma values are displayed.

     waveform
          per row/column color component graph. In row mode graph in the left side represents color component value 0 and right side represents value = 255. In column mode top side represents color component value = 0 and bottom side represents value = 255.

     Default value is levels.

level_height
     Set height of level in levels. Default value is 200. Allowed range is [50, 2048].

scale_height
     Set height of color scale in levels. Default value is 12. Allowed range is [0, 40].

step
     Set step for waveform mode. Smaller values are useful to find out how much of same luminance values across input rows/columns are distributed. Default value is 10. Allowed range is [1, 255].

waveform_mode
     Set mode for waveform. Can be either row, or column. Default is row.

display_mode
     Set display mode for waveform and levels. It accepts the following values:

     parade
          Display separate graph for the color components side by side in row waveform mode or one below other in column waveform mode for waveform histogram mode. For levels histogram mode per color component graphs are placed one bellow other.

          This display mode in waveform histogram 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 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 make by making adjustments to level the three waveforms.

     overlay
          Presents information that's identical to that in the parade, except that the graphs representing color components are superimposed directly over one another.

          This display mode in waveform histogram mode can make it easier to spot the relative differences or similarities in overlapping areas of the color components that are supposed to be identical, such as neutral whites, grays, or blacks.

     Default is parade.

levels_mode
     Set mode for levels. Can be either linear, or logarithmic. Default is linear.

Examples
--------

  * Calculate and draw histogram:

          ffplay -i input -vf histogram

hqdn3d
======

High precision/quality 3d denoise filter. This filter 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 float number which specifies spatial luma strength, defaults to 4.0

chroma_spatial
     a non-negative float number which specifies spatial chroma strength, defaults to 3.0*LUMA_SPATIAL/4.0

luma_tmp
     a float number which specifies luma temporal strength, defaults to 6.0*LUMA_SPATIAL/4.0

chroma_tmp
     a float number which specifies chroma temporal strength, defaults to LUMA_TMP*CHROMA_SPATIAL/LUMA_SPATIAL

hue
===

Modify the hue and/or the saturation of the input.

This filter accepts the following options:

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".

h and H are mutually exclusive, and can't be specified at the same time.

The 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:

s

h

H
     Modify the hue and/or the saturation 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.

idet
====

Detect video interlacing type.

This filter tries to detect if the input is interlaced or progressive, top or bottom field first.

The filter accepts the following options:

intl_thres
     Set interlacing threshold.

prog_thres
     Set progressive threshold.

il
==

Deinterleave or interleave fields.

This filter allows 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.

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
     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

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 input video.

LUTYUV applies a lookup table to a YUV input video, LUTRGB to an RGB input video.

These filters accept the following options:

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
     input value for the pixel component

clipval
     the input value clipped in the MINVAL-MAXVAL range

maxval
     maximum value for the pixel component

minval
     minimum value for the pixel component

negval
     the negated value for the pixel component value clipped in the MINVAL-MAXVAL range , it corresponds to the expression "maxval-clipval+minval"

clip(val)
     the computed value in VAL clipped in the MINVAL-MAXVAL range

gammaval(gamma)
     the computed gamma correction value of the pixel component value clipped in the MINVAL-MAXVAL range, 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, turns 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 0.5 factor:

          lutyuv=y=gammaval(0.5)

  * Discard least significant bits of luma:

          lutyuv=y='bitand(val, 128+64+32)'

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.

mp
==

Apply an MPlayer filter to the input video.

This filter provides a wrapper around most of the filters of MPlayer/MEncoder.

This wrapper is considered experimental. Some of the wrapped filters may not work properly and we may drop support for them, as they will be implemented natively into FFmpeg. Thus you should avoid depending on them when writing portable scripts.

The filters accepts the parameters: FILTER_NAME[:=]FILTER_PARAMS

FILTER_NAME is the name of a supported MPlayer filter, FILTER_PARAMS is a string containing the parameters accepted by the named filter.

The list of the currently supported filters follows:

dint

eq2

eq

fil

fspp

ilpack

perspective

phase

pp7

pullup

qp

softpulldown

uspp

The parameter syntax and behavior for the listed filters are the same of the corresponding MPlayer filters. For detailed instructions check the "VIDEO FILTERS" section in the MPlayer manual.

Examples
--------

  * Adjust gamma, brightness, contrast:

          mp=eq2=1.0:2:0.5

See also mplayer(1), http://www.mplayerhq.hu/.

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.

This filter accepts an integer in input, if non-zero it negates the alpha component (if available). The default value in input is 0.

noformat
========

Force libavfilter not to use any of the specified pixel formats for the input to the next filter.

This filter accepts the following parameters:

pix_fmts
     A '|'-separated list of pixel format names, for example "pix_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.

ocv
===

Apply video transform using libopencv.

To enable this filter install libopencv library and headers and configure FFmpeg with --enable-libopencv.

This filter 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://opencv.willowgarage.com/documentation/c/image_filtering.html

Follows the list of supported libopencv filters.

dilate
------

Dilate an image by using a specific structuring element. This filter 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, and can be one of the values "rect", "cross", "ellipse", "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.

Follow some example:

     # use the default values
     ocv=dilate

     # dilate using a structuring element with a 5x5 cross, iterate two times
     ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2

     # read the shape from the file diamond.shape, iterate two times
     # the file diamond.shape may contain a pattern of characters like this:
     #   *
     #  ***
     # *****
     #  ***
     #   *
     # the specified cols and rows are ignored (but not the anchor point coordinates)
     ocv=dilate:0x0+2x2/custom=diamond.shape|2

erode
-----

Erode an image by using a specific structuring element. This filter corresponds to the libopencv function cvErode.

The filter 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 can be one of the following values: "blur", "blur_no_scale", "median", "gaussian", "bilateral". The default value is "gaussian".

PARAM1, PARAM2, PARAM3, and PARAM4 are parameters whose meanings depend on smooth type. PARAM1 and PARAM2 accept integer positive values or 0, PARAM3 and PARAM4 accept float 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 one output, the first input is the "main" video on which the second input is overlayed.

This filter accepts the following parameters:

A description of the accepted options follows.

x

y
     Set the expression for the x and y coordinates of the overlayed 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).

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

     yuv444
          force YUV444 output

     rgb
          force 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, which is enabled by default.

The x, and y expressions can contain the following parameters.

main_w, W

main_h, H
     main input width and height

overlay_w, w

overlay_h, h
     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
     timestamp expressed in seconds, 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 a good idea to pass the two inputs through a SETPTS=PTS-STARTPTS filter to have them begin in the same zero timestamp, as it does the example for the MOVIE filter.

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]
          "

  * 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 given coordinates X, Y.

This filter 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 an expression for the offsets where to place the input image in 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, it can be the name of a color (case insensitive match) or a 0xRRGGBB[AA] sequence.

     The default value of COLOR is "black".

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
     same as IN_W and IN_H

out_w

out_h
     the output width and height, that is the size of the padded area as specified by the WIDTH and HEIGHT expressions

ow

oh
     same as OUT_W and OUT_H

x

y
     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
     horizontal and vertical chroma subsample values. For example for the pixel format "yuv422p" HSUB is 2 and VSUB is 1.

Examples
--------

  * Add paddings with color "violet" to the input video. Output video size is 640x480, 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 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"

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

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.

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. 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 heigth

out_w, ow

out_h, oh
     the output width and heigth, 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

  * 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 choosen 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 0.1-4.0. 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 0.1-2.0 range.

chroma_strength, cs
     Set chroma maximum difference between pixels to still be considered, must be a value in the 0.1-100.0 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.

The filter accepts the following options:

width, w
     Set the output video width expression. Default value is iw. See below for the list of accepted constants.

height, h
     Set the output video height expression. Default value is ih. See below for the list of accepted constants.

interl
     Set the interlacing. 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. If not explictly specified the filter applies a bilinear scaling algorithm.

size, s
     Set the video size, the value must be a valid abbreviation or in the form WIDTHxHEIGHT.

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
     same as IN_W and IN_H

out_w

out_h
     the output (cropped) width and height

ow

oh
     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.

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.

If the value for W or H is 0, the respective input size is used for the output.

If the value for W or H is -1, the scale filter will use, for the respective output size, a value that maintains the aspect ratio of the input image.

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 for 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, but make 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, keep the same input aspect ratio:

          scale=w='min(500\, iw*3/2):h=-1'

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.

The filters accept the following options:

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.

Examples
--------

  * To change the display aspect ratio to 16:9, specify one of the following:

          setdar=dar=1.77777
          setdar=dar=16/9
          setdar=dar=1.77777

  * 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.

A description of each shown parameter follows:

n
     sequential number of the input frame, starting from 0

pts
     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
     Presentation TimeStamp of the input frame, expressed as a number of 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 video)

fmt
     pixel format name

sar
     sample aspect ratio of the input frame, expressed in the form NUM/DEN

s
     size of the input frame, expressed in the form WIDTHxHEIGHT

i
     interlaced mode ("P" for "progressive", "T" for top field first, "B" for bottom field first)

iskey
     1 if the frame is a key frame, 0 otherwise

type
     picture type of the input frame ("I" for an I-frame, "P" for a P-frame, "B" for a B-frame, "?" for unknown type). Check also the documentation of the AVPictureType enum and of the av_get_picture_type_char function defined in libavutil/avutil.h.

checksum
     Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame

plane_checksum
     Adler-32 checksum (printed in hexadecimal) of each plane of the input frame, expressed in the form "[C0 C1 C2 C3]"

smartblur
=========

Blur the input video without impacting the outlines.

The filter 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 1.0.

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 1.0.

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 0.

If a chroma option is not explicitly set, the corresponding luma value is set.

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)

          Default value is sbsl.

out
     Set stereoscopic image format of output.

     Available values for output image formats are all the input formats as well as:

     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)

     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)

     ml
          mono output (left eye only)

     mr
          mono output (right eye only)

     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 bellow (left eye above, right eye below) to side by side crosseye.

          stereo3d=abl:sbsr

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. Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to correctly scale the fonts if the aspect ratio has been changed.

charenc
     Set subtitles input character encoding. subtitles filter only. Only useful if not UTF-8.

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

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.

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

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) in the form "WxH".

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.

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 accomodate 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.

     drop_odd, 1
          Only output even frames, odd frames are dropped, generating a frame with unchanged height at half frame rate.

     drop_even, 2
          Only output odd frames, even frames are dropped, generating a frame with unchanged height at half frame rate.

     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.

     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.

     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.

     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.

     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.

This filter accepts the following options:

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.

This filter accepts the following options:

start
     Timestamp (in seconds) of the start of the kept section. I.e. the frame with the timestamp START will be the first frame in the output.

end
     Timestamp (in seconds) 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
     Same as START, except this option sets the start timestamp in timebase units instead of seconds.

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

duration
     Maximum duration of the output in seconds.

start_frame
     Number of the first frame that should be passed to output.

end_frame
     Number of the first frame that should be dropped.

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 that the output timestamps 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 63, default value is 5.

luma_msize_y, ly
     Set the luma matrix vertical size. It must be an odd integer between 3 and 63, default value is 5.

luma_amount, la
     Set the luma effect strength. It can be a float 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 63, default value is 5.

chroma_msize_y, cy
     Set the chroma matrix vertical size. It must be an odd integer between 3 and 63, default value is 5.

chroma_amount, ca
     Set the chroma effect strength. It can be a float 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 strong blur of both luma and chroma parameters:

          unsharp=7:7:-2:7:7:-2

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 9.

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.

This filter accepts the following options:

input
     path to the file used to read the transforms (default: transforms.trf)

smoothing
     number of frames (value*2 + 1) used for lowpass filtering the camera movements (default: 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 values leads to a smoother video, but limits the acceleration of the camera (pan/tilt movements).

maxshift
     maximal number of pixels to translate frames (default: -1 no limit)

maxangle
     maximal angle in radians (degree*PI/180) to rotate frames (default: -1 no limit)

crop
     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

     0
          keep transforms normal (default)

     1
          invert transforms

relative
     consider transforms as

     0
          absolute

     1
          relative to previous frame (default)

zoom
     percentage to zoom (default: 0)

     >0
          zoom in

     <0
          zoom out

optzoom
     if 1 then optimal zoom value is determined (default). Optimal zoom means no (or only little) border should be visible. Note that the value given at zoom is added to the one calculated here.

interpol
     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
     virtual tripod mode means that the video is stabilized such that the camera stays stationary. Use also tripod option of vidstabdetect.

     0
          off (default)

     1
          virtual tripod mode: equivalent to relative=0:smoothing=0

Examples
--------

  * typical call with default default values: (note the unsharp filter which is always recommended)

          ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg

  * 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 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

yadif
=====

Deinterlace the input video ("yadif" means "yet another deinterlacing filter").

This filter accepts the following options:

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

     0, send_frame
          output 1 frame for each frame

     1, send_field
          output 1 frame for each field

     2, send_frame_nospatial
          like send_frame but skip spatial interlacing check

     3, send_field_nospatial
          like send_field but skip spatial interlacing check

     Default value is send_frame.

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

     0, tff
          assume top field first

     1, bff
          assume bottom field first

     -1, auto
          enable automatic detection

     Default value is auto. If interlacing is unknown or 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

     Default value is all.

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.

This source accepts the following options:

video_size
     Specify the size (width and height) of the buffered video frames.

width
     Input video width.

height
     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
     Specify the sample aspect ratio assumed by the video frames.

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.

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.

     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

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. 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 float number or a valid video frame rate abbreviation. The default value is "25".

duration, d
     Set the video duration of the sourced video. The accepted syntax is:

          [-]HH:MM:SS[.m...]
          [-]S+[.m...]

     See also the function av_parse_time().

     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.

For example the following:

     testsrc=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 options:

size
     The size of the video to generate, may be a string of the form WIDTHxHEIGHT or a frame size abbreviation.

framerate
     Framerate of the generated video, 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 section frei0r in the description of the video filters.

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 overlayed 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 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.

     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.

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

color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
========================================================================

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 sources accept the following options:

color, c
     Specify the color of the source, only available in the color source. It can be the name of a color (case insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an alpha specifier. The default value is "black".

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, it may be a string of the form WIDTHxHEIGHT, or the name of a size abbreviation. 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 float 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 video duration of the sourced video. The accepted syntax is:

          [-]HH[:MM[:SS[.m...]]]
          [-]S+[.m...]

     See also the function av_parse_time().

     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 a 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 to be employed in analysis / debugging tools.

Multimedia Filters
******************

Below is a description of the currently available multimedia filters.

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.

     Default value is lissajous.

size, s
     Set the video size for the output. Default value is 400x400.

rate, r
     Set the output frame rate. Default value is 25.

rc

gc

bc
     Specify the red, green and blue contrast. Default values are 40, 160 and 80. Allowed range is [0, 255].

rf

gf

bf
     Specify the red, green and blue fade. Default values are 15, 10 and 5. Allowed range is [0, 255].

zoom
     Set the zoom factor. Default value is 1. Allowed range is [1, 10].

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]'

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 video 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.

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. 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.

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 a 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 drop 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 will send 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

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.

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, NAN if undefined

TB
     timebase of the input timestamps

pts
     the PTS (Presentation TimeStamp) of the filtered video frame, expressed in TB units, NAN if undefined

t
     the PTS (Presentation TimeStamp) of the filtered video frame, expressed in seconds, NAN if undefined

prev_pts
     the PTS of the previously filtered video frame, NAN if undefined

prev_selected_pts
     the PTS of the last previously filtered video frame, NAN if undefined

prev_selected_t
     the PTS of the last previously selected video frame, NAN if undefined

start_pts
     the PTS of the first video frame in the video, NAN if undefined

start_t
     the time of the first video frame in the video, NAN if undefined

pict_type (video only)
     the type of the filtered frame, can assume one of the following values:

     I

     P

     B

     S

     SI

     SP

     BI

interlace_type (video only)
     the frame interlace type, 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
     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)

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='gte(t\,10)*lte(t\,20)'

  * Select only I frames contained in the 10-20 time interval:

          select='gte(t\,10)*lte(t\,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

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
     audio sample rate

STARTPTS
     the PTS of the first frame

STARTT
     the time in seconds of the first frame

INTERLACED
     tell if the current frame is interlaced

T
     the time in seconds of the current frame

TB
     the time base

POS
     original position in the file of the frame, or undefined if undefined for the current frame

PREV_INPTS
     previous input PTS

PREV_INT
     previous input time in seconds

PREV_OUTPTS
     previous output PTS

PREV_OUTT
     previous output time in seconds

RTCTIME
     wallclock (RTC) time in microseconds. This is deprecated, use time(0) instead.

RTCSTART
     wallclock (RTC) time at the start of the movie in microseconds

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.

This filter accepts the following options:

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

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. Default value is 640x512.

slide
     Specify if the spectrum should slide along the window. Default value is 0.

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 is displayed using the same 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

     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.

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]'

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. 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.

     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".

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]

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.

This filter accepts the following options:

filename
     The name of the resource to read (not necessarily a file but also 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. 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 best suited video stream will be automatically selected. 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 less than 1, the stream will be read again and again. 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.

This filter allows to overlay a second video on top of 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 as "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 as "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]