+@chapter Filtering Introduction
+@c man begin 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.
+
+@example
+ [main]
+input --> split ---------------------> overlay --> output
+ | ^
+ |[tmp] [flip]|
+ +-----> crop --> vflip -------+
+@end example
+
+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:
+
+@example
+ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
+@end example
+
+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,
+@var{crop,vflip} are in one linear chain, @var{split} and
+@var{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 @var{[main]} and @var{[tmp]}.
+
+The stream sent to the second output of @var{split}, labelled as
+@var{[tmp]}, is processed through the @var{crop} filter, which crops
+away the lower half part of the video, and then vertically flipped. The
+@var{overlay} filter takes in input the first unchanged output of the
+split filter (which was labelled as @var{[main]}), and overlay on its
+lower half the output generated by the @var{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 @var{source filters} that do not have an
+audio/video input, and @var{sink filters} that will not have audio/video
+output.
+
+@c man end FILTERING INTRODUCTION
+
+@chapter graph2dot
+@c man begin GRAPH2DOT
+
+The @file{graph2dot} program included in the FFmpeg @file{tools}
+directory can be used to parse a filtergraph description and issue a
+corresponding textual representation in the dot language.
+
+Invoke the command:
+@example
+graph2dot -h
+@end example
+
+to see how to use @file{graph2dot}.
+
+You can then pass the dot description to the @file{dot} program (from
+the graphviz suite of programs) and obtain a graphical representation
+of the filtergraph.
+
+For example the sequence of commands:
+@example
+echo @var{GRAPH_DESCRIPTION} | \
+tools/graph2dot -o graph.tmp && \
+dot -Tpng graph.tmp -o graph.png && \
+display graph.png
+@end example
+
+can be used to create and display an image representing the graph
+described by the @var{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:
+@example
+ffmpeg -i infile -vf scale=640:360 outfile
+@end example
+your @var{GRAPH_DESCRIPTION} string will need to be of the form:
+@example
+nullsrc,scale=640:360,nullsink
+@end example
+you may also need to set the @var{nullsrc} parameters and add a @var{format}
+filter in order to simulate a specific input file.
+
+@c man end GRAPH2DOT
+
@chapter Filtergraph description
@c man begin FILTERGRAPH DESCRIPTION
A filtergraph can be represented using a textual representation, which is
recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
-options in @command{avconv} and @option{-vf} in @command{avplay}, and by the
+options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
@code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
@file{libavfilter/avfilter.h}.
"=@var{arguments}".
@var{arguments} is a string which contains the parameters used to
-initialize the filter instance. It may have one of the two allowed forms:
+initialize the filter instance. It may have one of the following forms:
@itemize
@item
@var{in} is assigned to the option @option{type}, @var{0} to
@option{start_frame} and @var{30} to @option{nb_frames}.
+@item
+A ':'-separated list of mixed direct @var{value} and long @var{key=value}
+pairs. The direct @var{value} must precede the @var{key=value} pairs, and
+follow the same constraints order of the previous point. The following
+@var{key=value} pairs can be set in any preferred order.
+
@end itemize
If the option value itself is a list of items (e.g. the @code{format} filter
@var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
@end example
+@section Notes on filtergraph escaping
+
+Filtergraph description composition entails several levels of
+escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
+section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
+information about the employed escaping procedure.
+
+A first level escaping affects the content of each filter option
+value, which may contain the special character @code{:} used to
+separate values, or one of the escaping characters @code{\'}.
+
+A second level escaping affects the whole filter description, which
+may contain the escaping characters @code{\'} or the special
+characters @code{[],;} used by the filtergraph description.
+
+Finally, when you specify a filtergraph on a shell commandline, you
+need to perform a third level escaping for the shell special
+characters contained within it.
+
+For example, consider the following string to be embedded in
+the @ref{drawtext} filter description @option{text} value:
+@example
+this is a 'string': may contain one, or more, special characters
+@end example
+
+This string contains the @code{'} special escaping character, and the
+@code{:} special character, so it needs to be escaped in this way:
+@example
+text=this is a \'string\'\: may contain one, or more, special characters
+@end example
+
+A second level of escaping is required when embedding the filter
+description in a filtergraph description, in order to escape all the
+filtergraph special characters. Thus the example above becomes:
+@example
+drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
+@end example
+(note that in addition to the @code{\'} escaping special characters,
+also @code{,} needs to be escaped).
+
+Finally an additional level of escaping is needed when writing the
+filtergraph description in a shell command, which depends on the
+escaping rules of the adopted shell. For example, assuming that
+@code{\} is special and needs to be escaped with another @code{\}, the
+previous string will finally result in:
+@example
+-vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
+@end example
+
+@chapter Timeline editing
+
+Some filters support a generic @option{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:
+@table @samp
+@item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+@item n
+sequential number of the input frame, starting from 0
+
+@item pos
+the position in the file of the input frame, NAN if unknown
+@end table
+
+Additionally, these filters support an @option{enable} command that can be used
+to re-define the expression.
+
+Like any other filtering option, the @option{enable} option follows the same
+rules.
+
+For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
+minutes, and a @ref{curves} filter starting at 3 seconds:
+@example
+smartblur = enable='between(t,10,3*60)',
+curves = enable='gte(t,3)' : preset=cross_process
+@end example
+
@c man end FILTERGRAPH DESCRIPTION
@chapter Audio Filters
@c man begin AUDIO FILTERS
-When you configure your Libav build, you can disable any of the
-existing filters using --disable-filters.
+When you configure your FFmpeg build, you can disable any of the
+existing filters using @code{--disable-filters}.
The configure output will show the audio filters included in your
build.
Below is a description of the currently available audio filters.
+@section aconvert
+
+Convert the input audio format to the specified formats.
+
+@emph{This filter is deprecated. Use @ref{aformat} instead.}
+
+The filter accepts a string of the form:
+"@var{sample_format}:@var{channel_layout}".
+
+@var{sample_format} specifies the sample format, and can be a string or the
+corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
+suffix for a planar sample format.
+
+@var{channel_layout} specifies the channel layout, and can be a string
+or the corresponding number value defined in @file{libavutil/channel_layout.h}.
+
+The special parameter "auto", signifies that the filter will
+automatically select the output format depending on the output filter.
+
+@subsection Examples
+
+@itemize
+@item
+Convert input to float, planar, stereo:
+@example
+aconvert=fltp:stereo
+@end example
+
+@item
+Convert input to unsigned 8-bit, automatically select out channel layout:
+@example
+aconvert=u8:auto
+@end example
+@end itemize
+
+@section adelay
+
+Delay one or more audio channels.
+
+Samples in delayed channel are filled with silence.
+
+The filter accepts the following option:
+
+@table @option
+@item delays
+Set list of delays in milliseconds for each channel separated by '|'.
+At least one delay greater than 0 should be provided.
+Unused delays will be silently ignored. If number of given delays is
+smaller than number of channels all remaining channels will not be delayed.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
+the second channel (and any other channels that may be present) unchanged.
+@example
+adelay=1500|0|500
+@end example
+@end itemize
+
+@section aecho
+
+Apply echoing to the input audio.
+
+Echoes are reflected sound and can occur naturally amongst mountains
+(and sometimes large buildings) when talking or shouting; digital echo
+effects emulate this behaviour and are often used to help fill out the
+sound of a single instrument or vocal. The time difference between the
+original signal and the reflection is the @code{delay}, and the
+loudness of the reflected signal is the @code{decay}.
+Multiple echoes can have different delays and decays.
+
+A description of the accepted parameters follows.
+
+@table @option
+@item in_gain
+Set input gain of reflected signal. Default is @code{0.6}.
+
+@item out_gain
+Set output gain of reflected signal. Default is @code{0.3}.
+
+@item delays
+Set list of time intervals in milliseconds between original signal and reflections
+separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
+Default is @code{1000}.
+
+@item decays
+Set list of loudnesses of reflected signals separated by '|'.
+Allowed range for each @code{decay} is @code{(0 - 1.0]}.
+Default is @code{0.5}.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Make it sound as if there are twice as many instruments as are actually playing:
+@example
+aecho=0.8:0.88:60:0.4
+@end example
+
+@item
+If delay is very short, then it sound like a (metallic) robot playing music:
+@example
+aecho=0.8:0.88:6:0.4
+@end example
+
+@item
+A longer delay will sound like an open air concert in the mountains:
+@example
+aecho=0.8:0.9:1000:0.3
+@end example
+
+@item
+Same as above but with one more mountain:
+@example
+aecho=0.8:0.9:1000|1800:0.3|0.25
+@end example
+@end itemize
+
+@section aeval
+
+Modify an audio signal according to the specified expressions.
+
+This filter accepts one or more expressions (one for each channel),
+which are evaluated and used to modify a corresponding audio signal.
+
+This filter accepts the following options:
+
+@table @option
+@item exprs
+Set the '|'-separated expressions list for each separate channel. If
+the number of input channels is greater than the number of
+expressions, the last specified expression is used for the remaining
+output channels.
+
+@item channel_layout, c
+Set output channel layout. If not specified, the channel layout is
+specified by the number of expressions. If set to @samp{same}, it will
+use by default the same input channel layout.
+@end table
+
+Each expression in @var{exprs} can contain the following constants and functions:
+
+@table @option
+@item ch
+channel number of the current expression
+
+@item n
+number of the evaluated sample, starting from 0
+
+@item s
+sample rate
+
+@item t
+time of the evaluated sample expressed in seconds
+
+@item nb_in_channels
+@item nb_out_channels
+input and output number of channels
+
+@item val(CH)
+the value of input channel with number @var{CH}
+@end table
+
+Note: this filter is slow. For faster processing you should use a
+dedicated filter.
+
+@subsection Examples
+
+@itemize
+@item
+Half volume:
+@example
+aeval=val(ch)/2:c=same
+@end example
+
+@item
+Invert phase of the second channel:
+@example
+eval=val(0)|-val(1)
+@end example
+@end itemize
+
+@section afade
+
+Apply fade-in/out effect to input audio.
+
+A description of the accepted parameters follows.
+
+@table @option
+@item type, t
+Specify the effect type, can be either @code{in} for fade-in, or
+@code{out} for a fade-out effect. Default is @code{in}.
+
+@item start_sample, ss
+Specify the number of the start sample for starting to apply the fade
+effect. Default is 0.
+
+@item 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.
+
+@item start_time, st
+Specify time for starting to apply the fade effect. Default is 0.
+The accepted syntax is:
+@example
+[-]HH[:MM[:SS[.m...]]]
+[-]S+[.m...]
+@end example
+See also the function @code{av_parse_time()}.
+If set this option is used instead of @var{start_sample} one.
+
+@item duration, d
+Specify the duration for which the fade effect has to last. Default is 0.
+The accepted syntax is:
+@example
+[-]HH[:MM[:SS[.m...]]]
+[-]S+[.m...]
+@end example
+See also the function @code{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 @var{nb_samples} one.
+
+@item curve
+Set curve for fade transition.
+
+It accepts the following values:
+@table @option
+@item tri
+select triangular, linear slope (default)
+@item qsin
+select quarter of sine wave
+@item hsin
+select half of sine wave
+@item esin
+select exponential sine wave
+@item log
+select logarithmic
+@item par
+select inverted parabola
+@item qua
+select quadratic
+@item cub
+select cubic
+@item squ
+select square root
+@item cbr
+select cubic root
+@end table
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Fade in first 15 seconds of audio:
+@example
+afade=t=in:ss=0:d=15
+@end example
+
+@item
+Fade out last 25 seconds of a 900 seconds audio:
+@example
+afade=t=out:st=875:d=25
+@end example
+@end itemize
+
+@anchor{aformat}
@section aformat
-Convert the input audio to one of the specified formats. The framework will
+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:
@item channel_layouts
A '|'-separated list of requested channel layouts.
+See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
+for the required syntax.
@end table
If a parameter is omitted, all values are allowed.
aformat=sample_fmts=u8|s16:channel_layouts=stereo
@end example
+@section allpass
+
+Apply a two-pole all-pass filter with central frequency (in Hz)
+@var{frequency}, and filter-width @var{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:
+
+@table @option
+@item frequency, f
+Set frequency in Hz.
+
+@item width_type
+Set method to specify band-width of filter.
+@table @option
+@item h
+Hz
+@item q
+Q-Factor
+@item o
+octave
+@item s
+slope
+@end table
+
+@item width, w
+Specify the band-width of a filter in width_type units.
+@end table
+
+@section amerge
+
+Merge two or more audio streams into a single multi-channel stream.
+
+The filter accepts the following options:
+
+@table @option
+
+@item inputs
+Set the number of inputs. Default is 2.
+
+@end table
+
+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.
+
+@subsection Examples
+
+@itemize
+@item
+Merge two mono files into a stereo stream:
+@example
+amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
+@end example
+
+@item
+Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
+@example
+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
+@end example
+@end itemize
+
@section amix
Mixes multiple audio inputs into a single output.
For example
@example
-avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
+ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
@end example
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.
Pass the audio source unchanged to the output.
-@section asetpts
+@section apad
-Change the PTS (presentation timestamp) of the input audio frames.
+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.
-This filter accepts the following options:
+@section 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.
@table @option
+@item in_gain
+Set input gain. Default is 0.4.
-@item expr
-The expression which is evaluated for each frame to construct its timestamp.
+@item out_gain
+Set output gain. Default is 0.74
-@end table
+@item delay
+Set delay in milliseconds. Default is 3.0.
-The expression is evaluated through the eval API and can contain the following
-constants:
+@item decay
+Set decay. Default is 0.4.
-@table @option
-@item PTS
-the presentation timestamp in input
+@item speed
+Set modulation speed in Hz. Default is 0.5.
-@item PI
-Greek PI
+@item type
+Set modulation type. Default is triangular.
-@item PHI
-golden ratio
+It accepts the following values:
+@table @samp
+@item triangular, t
+@item sinusoidal, s
+@end table
+@end table
-@item E
-Euler number
+@anchor{aresample}
+@section aresample
-@item N
-Number of the audio samples pass through the filter so far, starting at 0.
+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.
-@item S
-Number of the audio samples in the current frame.
+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.
-@item SR
-Audio sample rate.
+The filter accepts the syntax
+[@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
+expresses a sample rate and @var{resampler_options} is a list of
+@var{key}=@var{value} pairs, separated by ":". See the
+ffmpeg-resampler manual for the complete list of supported options.
-@item STARTPTS
-the PTS of the first frame
+@subsection Examples
-@item PREV_INPTS
-previous input PTS
+@itemize
+@item
+Resample the input audio to 44100Hz:
+@example
+aresample=44100
+@end example
-@item PREV_OUTPTS
-previous output PTS
+@item
+Stretch/squeeze samples to the given timestamps, with a maximum of 1000
+samples per second compensation:
+@example
+aresample=async=1000
+@end example
+@end itemize
-@item RTCTIME
-wallclock (RTC) time in microseconds
+@section asetnsamples
-@item RTCSTART
-wallclock (RTC) time at the start of the movie in microseconds
+Set the number of samples per each output audio frame.
-@end table
+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.
-Some examples follow:
+The filter accepts the following options:
-@example
-# start counting PTS from zero
-asetpts=expr=PTS-STARTPTS
+@table @option
+
+@item nb_out_samples, n
+Set the number of frames per each output audio frame. The number is
+intended as the number of samples @emph{per each channel}.
+Default value is 1024.
-#generate timestamps by counting samples
-asetpts=expr=N/SR/TB
+@item 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.
+@end table
-# generate timestamps from a "live source" and rebase onto the current timebase
-asetpts='(RTCTIME - RTCSTART) / (TB * 1000000)"
+For example, to set the number of per-frame samples to 1234 and
+disable padding for the last frame, use:
+@example
+asetnsamples=n=1234:p=0
@end example
+@section 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:
+
+@table @option
+@item sample_rate, r
+Set the output sample rate. Default is 44100 Hz.
+@end table
@section ashowinfo
@item pts_time
presentation timestamp of the input frame in seconds
+@item 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)
+
@item fmt
sample format
A list of Adler-32 checksums for each data plane.
@end table
-@section asplit
+@section astats
-Split input audio into several identical outputs.
+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 a single parameter which specifies the number of outputs. If
-unspecified, it defaults to 2.
+The filter accepts the following option:
+@table @option
+@item length
+Short window length in seconds, used for peak and trough RMS measurement.
+Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
+@end table
-For example
+A description of each shown parameter follows:
+
+@table @option
+@item DC offset
+Mean amplitude displacement from zero.
+
+@item Min level
+Minimal sample level.
+
+@item Max level
+Maximal sample level.
+
+@item Peak level dB
+@item RMS level dB
+Standard peak and RMS level measured in dBFS.
+
+@item RMS peak dB
+@item RMS trough dB
+Peak and trough values for RMS level measured over a short window.
+
+@item Crest factor
+Standard ratio of peak to RMS level (note: not in dB).
+
+@item Flat factor
+Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
+(i.e. either @var{Min level} or @var{Max level}).
+
+@item Peak count
+Number of occasions (not the number of samples) that the signal attained either
+@var{Min level} or @var{Max level}.
+@end table
+
+@section astreamsync
+
+Forward two audio streams and control the order the buffers are forwarded.
+
+The filter accepts the following options:
+
+@table @option
+@item 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:
+
+@table @var
+@item b1 b2
+number of buffers forwarded so far on each stream
+@item s1 s2
+number of samples forwarded so far on each stream
+@item t1 t2
+current timestamp of each stream
+@end table
+
+The default value is @code{t1-t2}, which means to always forward the stream
+that has a smaller timestamp.
+@end table
+
+@subsection Examples
+
+Stress-test @code{amerge} by randomly sending buffers on the wrong
+input, while avoiding too much of a desynchronization:
@example
-avconv -i INPUT -filter_complex asplit=5 OUTPUT
+amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
+[a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
+[a2] [b2] amerge
@end example
-will create 5 copies of the input audio.
@section 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 @ref{aresample} to do squeezing/stretching.
+
The filter accepts the following named parameters:
@table @option
@end table
+@section 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.
+
+@subsection Examples
+
+@itemize
+@item
+Slow down audio to 80% tempo:
+@example
+atempo=0.8
+@end example
+
+@item
+To speed up audio to 125% tempo:
+@example
+atempo=1.25
+@end example
+@end itemize
+
@section atrim
+
Trim the input so that the output contains one continuous subpart of the input.
This filter accepts the following options:
@table @option
@item start
-Timestamp (in seconds) of the start of the kept section. I.e. the audio sample
+Specify time of the start of the kept section, i.e. the audio sample
with the timestamp @var{start} will be the first sample in the output.
@item end
-Timestamp (in seconds) of the first audio sample that will be dropped. I.e. the
+Specify time of the first audio sample that will be dropped, i.e. the
audio sample immediately preceding the one with the timestamp @var{end} will be
the last sample in the output.
of seconds.
@item duration
-Maximum duration of the output in seconds.
+Specify maximum duration of the output.
@item start_sample
Number of the first sample that should be passed to output.
Number of the first sample that should be dropped.
@end table
+@option{start}, @option{end}, @option{duration} are expressed as time
+duration specifications, check the "Time duration" section in the
+ffmpeg-utils manual.
+
Note that the first two sets of the start/end options and the @option{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
@item
drop everything except the second minute of input
@example
-avconv -i INPUT -af atrim=60:120
+ffmpeg -i INPUT -af atrim=60:120
@end example
@item
keep only the first 1000 samples
@example
-avconv -i INPUT -af atrim=end_sample=1000
+ffmpeg -i INPUT -af atrim=end_sample=1000
@end example
@end itemize
-@section channelsplit
-Split each channel in input audio stream into a separate output stream.
+@section bandpass
+
+Apply a two-pole Butterworth band-pass filter with central
+frequency @var{frequency}, and (3dB-point) band-width width.
+The @var{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:
-This filter accepts the following named parameters:
@table @option
-@item channel_layout
-Channel layout of the input stream. Default is "stereo".
+@item frequency, f
+Set the filter's central frequency. Default is @code{3000}.
+
+@item csg
+Constant skirt gain if set to 1. Defaults to 0.
+
+@item width_type
+Set method to specify band-width of filter.
+@table @option
+@item h
+Hz
+@item q
+Q-Factor
+@item o
+octave
+@item s
+slope
@end table
-For example, assuming a stereo input MP3 file
-@example
-avconv -i in.mp3 -filter_complex channelsplit out.mkv
-@end example
-will create an output Matroska file with two audio streams, one containing only
-the left channel and the other the right channel.
+@item width, w
+Specify the band-width of a filter in width_type units.
+@end table
-To split a 5.1 WAV file into per-channel files
-@example
-avconv -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
-@end example
+@section bandreject
+
+Apply a two-pole Butterworth band-reject filter with central
+frequency @var{frequency}, and (3dB-point) band-width @var{width}.
+The filter roll off at 6dB per octave (20dB per decade).
+
+The filter accepts the following options:
+
+@table @option
+@item frequency, f
+Set the filter's central frequency. Default is @code{3000}.
+
+@item width_type
+Set method to specify band-width of filter.
+@table @option
+@item h
+Hz
+@item q
+Q-Factor
+@item o
+octave
+@item s
+slope
+@end table
+
+@item width, w
+Specify the band-width of a filter in width_type units.
+@end table
+
+@section 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:
+
+@table @option
+@item 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.
+
+@item 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 @code{100} Hz.
+
+@item width_type
+Set method to specify band-width of filter.
+@table @option
+@item h
+Hz
+@item q
+Q-Factor
+@item o
+octave
+@item s
+slope
+@end table
+
+@item width, w
+Determine how steep is the filter's shelf transition.
+@end table
+
+@section biquad
+
+Apply a biquad IIR filter with the given coefficients.
+Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
+are the numerator and denominator coefficients respectively.
@section channelmap
+
Remap input channels to new locations.
This filter accepts the following named parameters:
For example, assuming a 5.1+downmix input MOV file
@example
-avconv -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
+ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
@end example
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
@example
-avconv -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
+ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
+@end example
+
+@section channelsplit
+
+Split each channel in input audio stream into a separate output stream.
+
+This filter accepts the following named parameters:
+@table @option
+@item channel_layout
+Channel layout of the input stream. Default is "stereo".
+@end table
+
+For example, assuming a stereo input MP3 file
+@example
+ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
+@end example
+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
+@example
+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
@end example
@section compand
@item points
Set list of points for the transfer function, specified in dB relative to the
maximum possible signal amplitude. Each key points list must be defined using
-the following syntax: @code{x0/y0|x1/y1|x2/y2|....}
+the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
+@code{x0/y0 x1/y1 x2/y2 ....}
The input values must be in strictly increasing order but the transfer function
does not have to be monotonically rising. The point @code{0/0} is assumed but
@end example
@end itemize
+@section 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.
+
+@section 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:
+
+@table @option
+@item frequency, f
+Set the filter's central frequency in Hz.
+
+@item width_type
+Set method to specify band-width of filter.
+@table @option
+@item h
+Hz
+@item q
+Q-Factor
+@item o
+octave
+@item s
+slope
+@end table
+
+@item width, w
+Specify the band-width of a filter in width_type units.
+
+@item gain, g
+Set the required gain or attenuation in dB.
+Beware of clipping when using a positive gain.
+@end table
+
+@subsection Examples
+@itemize
+@item
+Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
+@example
+equalizer=f=1000:width_type=h:width=200:g=-10
+@end example
+
+@item
+Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
+@example
+equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
+@end example
+@end itemize
+
+@section 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:
+
+@table @option
+@item frequency, f
+Set frequency in Hz. Default is 3000.
+
+@item poles, p
+Set number of poles. Default is 2.
+
+@item width_type
+Set method to specify band-width of filter.
+@table @option
+@item h
+Hz
+@item q
+Q-Factor
+@item o
+octave
+@item s
+slope
+@end table
+
+@item 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.
+@end table
+
@section join
+
Join multiple input streams into one multi-channel stream.
The filter accepts the following named parameters:
E.g. to join 3 inputs (with properly set channel layouts)
@example
-avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
+ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
@end example
To build a 5.1 output from 6 single-channel streams:
@example
-avconv -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
+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
@end example
-@section resample
-Convert the audio sample format, sample rate and channel layout. This filter is
-not meant to be used directly, it is inserted automatically by libavfilter
-whenever conversion is needed. Use the @var{aformat} filter to force a specific
-conversion.
+@section ladspa
-@section volume
+Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
-Adjust the input audio volume.
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-ladspa}.
-The filter accepts the following named parameters:
@table @option
+@item file, f
+Specifies the name of LADSPA plugin library to load. If the environment
+variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
+each one of the directories specified by the colon separated list in
+@env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
+this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
+@file{/usr/lib/ladspa/}.
+
+@item plugin, p
+Specifies the plugin within the library. Some libraries contain only
+one plugin, but others contain many of them. If this is not set filter
+will list all available plugins within the specified library.
+
+@item controls, c
+Set the '|' separated list of controls which are zero or more floating point
+values that determine the behavior of the loaded plugin (for example delay,
+threshold or gain).
+Controls need to be defined using the following syntax:
+c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
+@var{valuei} is the value set on the @var{i}-th control.
+If @option{controls} is set to @code{help}, all available controls and
+their valid ranges are printed.
+
+@item sample_rate, s
+Specify the sample rate, default to 44100. Only used if plugin have
+zero inputs.
+
+@item nb_samples, n
+Set the number of samples per channel per each output frame, default
+is 1024. Only used if plugin have zero inputs.
+
+@item duration, d
+Set the minimum duration of the sourced audio. See the function
+@code{av_parse_time()} for the accepted format, also check the "Time duration"
+section in the ffmpeg-utils manual.
+Note that the resulting duration may be greater than the specified duration,
+as the generated audio is always cut at the end of a complete frame.
+If not specified, or the expressed duration is negative, the audio is
+supposed to be generated forever.
+Only used if plugin have zero inputs.
-@item volume
-Expresses how the audio volume will be increased or decreased.
+@end table
-Output values are clipped to the maximum value.
+@subsection Examples
-The output audio volume is given by the relation:
+@itemize
+@item
+List all available plugins within amp (LADSPA example plugin) library:
@example
-@var{output_volume} = @var{volume} * @var{input_volume}
+ladspa=file=amp
@end example
-Default value for @var{volume} is 1.0.
-
-@item precision
-Mathematical precision.
+@item
+List all available controls and their valid ranges for @code{vcf_notch}
+plugin from @code{VCF} library:
+@example
+ladspa=f=vcf:p=vcf_notch:c=help
+@end example
-This determines which input sample formats will be allowed, which affects the
-precision of the volume scaling.
+@item
+Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
+plugin library:
+@example
+ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
+@end example
-@table @option
-@item fixed
-8-bit fixed-point; limits input sample format to U8, S16, and S32.
-@item float
-32-bit floating-point; limits input sample format to FLT. (default)
-@item double
-64-bit floating-point; limits input sample format to DBL.
-@end table
-@end table
+@item
+Add reverberation to the audio using TAP-plugins
+(Tom's Audio Processing plugins):
+@example
+ladspa=file=tap_reverb:tap_reverb
+@end example
-@subsection Examples
+@item
+Generate white noise, with 0.2 amplitude:
+@example
+ladspa=file=cmt:noise_source_white:c=c0=.2
+@end example
-@itemize
@item
-Halve the input audio volume:
+Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
+@code{C* Audio Plugin Suite} (CAPS) library:
@example
-volume=volume=0.5
-volume=volume=1/2
-volume=volume=-6.0206dB
+ladspa=file=caps:Click:c=c1=20'
@end example
@item
-Increase input audio power by 6 decibels using fixed-point precision:
+Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
@example
-volume=volume=6dB:precision=fixed
+ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
@end example
@end itemize
-@c man end AUDIO FILTERS
+@subsection Commands
-@chapter Audio Sources
-@c man begin AUDIO SOURCES
+This filter supports the following commands:
+@table @option
+@item cN
+Modify the @var{N}-th control value.
-Below is a description of the currently available audio sources.
+If the specified value is not valid, it is ignored and prior one is kept.
+@end table
-@section anullsrc
+@section lowpass
-Null audio source, never return audio frames. It is mainly useful as a
-template and to be employed in analysis / debugging tools.
+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).
-It accepts as optional parameter a string of the form
-@var{sample_rate}:@var{channel_layout}.
+The filter accepts the following options:
-@var{sample_rate} specify the sample rate, and defaults to 44100.
+@table @option
+@item frequency, f
+Set frequency in Hz. Default is 500.
-@var{channel_layout} specify the channel layout, and can be either an
-integer or a string representing a channel layout. The default value
-of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
+@item poles, p
+Set number of poles. Default is 2.
-Check the channel_layout_map definition in
-@file{libavutil/channel_layout.c} for the mapping between strings and
-channel layout values.
+@item width_type
+Set method to specify band-width of filter.
+@table @option
+@item h
+Hz
+@item q
+Q-Factor
+@item o
+octave
+@item s
+slope
+@end table
-Follow some examples:
-@example
-# set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
-anullsrc=48000:4
+@item 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.
+@end table
-# same as
-anullsrc=48000:mono
-@end example
+@section pan
-@section abuffer
-Buffer audio frames, and make them available to the filter chain.
+Mix channels with specific gain levels. The filter accepts the output
+channel layout followed by a set of channels definitions.
-This source is not intended to be part of user-supplied graph descriptions but
-for insertion by calling programs through the interface defined in
-@file{libavfilter/buffersrc.h}.
+This filter is also designed to remap efficiently the channels of an audio
+stream.
+
+The filter accepts parameters of the form:
+"@var{l}:@var{outdef}:@var{outdef}:..."
-It accepts the following named parameters:
@table @option
+@item l
+output channel layout or number of channels
-@item time_base
-Timebase which will be used for timestamps of submitted frames. It must be
-either a floating-point number or in @var{numerator}/@var{denominator} form.
+@item outdef
+output channel specification, of the form:
+"@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
-@item sample_rate
-Audio sample rate.
+@item out_name
+output channel to define, either a channel name (FL, FR, etc.) or a channel
+number (c0, c1, etc.)
-@item sample_fmt
-Name of the sample format, as returned by @code{av_get_sample_fmt_name()}.
+@item gain
+multiplicative coefficient for the channel, 1 leaving the volume unchanged
-@item channel_layout
-Channel layout of the audio data, in the form that can be accepted by
-@code{av_get_channel_layout()}.
+@item in_name
+input channel to use, see out_name for details; it is not possible to mix
+named and numbered input channels
@end table
-All the parameters need to be explicitly defined.
-
-@c man end AUDIO SOURCES
-
-@chapter Audio Sinks
-@c man begin AUDIO SINKS
-
-Below is a description of the currently available audio sinks.
-
-@section 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.
+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.
-@section abuffersink
-This sink is intended for programmatic use. Frames that arrive on this sink can
-be retrieved by the calling program using the interface defined in
-@file{libavfilter/buffersink.h}.
+@subsection Mixing examples
-This filter accepts no parameters.
+For example, if you want to down-mix from stereo to mono, but with a bigger
+factor for the left channel:
+@example
+pan=1:c0=0.9*c0+0.1*c1
+@end example
-@c man end AUDIO SINKS
+A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
+7-channels surround:
+@example
+pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
+@end example
-@chapter Video Filters
-@c man begin VIDEO FILTERS
+Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
+that should be preferred (see "-ac" option) unless you have very specific
+needs.
-When you configure your Libav build, you can disable any of the
-existing filters using --disable-filters.
-The configure output will show the video filters included in your
-build.
+@subsection Remapping examples
-Below is a description of the currently available video filters.
+The channel remapping will be effective if, and only if:
-@section blackframe
+@itemize
+@item gain coefficients are zeroes or ones,
+@item only one input per channel output,
+@end itemize
-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.
+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.
-In order to display the output lines, you need to set the loglevel at
-least to the AV_LOG_INFO value.
+For example, if you have a 5.1 source and want a stereo audio stream by
+dropping the extra channels:
+@example
+pan="stereo: c0=FL : c1=FR"
+@end example
-The filter accepts the following options:
+Given the same source, you can also switch front left and front right channels
+and keep the input channel layout:
+@example
+pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
+@end example
-@table @option
+If the input is a stereo audio stream, you can mute the front left channel (and
+still keep the stereo channel layout) with:
+@example
+pan="stereo:c1=c1"
+@end example
-@item amount
-The percentage of the pixels that have to be below the threshold, defaults to
-98.
+Still with a stereo audio stream input, you can copy the right channel in both
+front left and right:
+@example
+pan="stereo: c0=FR : c1=FR"
+@end example
-@item threshold
-Threshold below which a pixel value is considered black, defaults to 32.
+@section replaygain
-@end table
+ReplayGain scanner filter. This filter takes an audio stream as an input and
+outputs it unchanged.
+At end of filtering it displays @code{track_gain} and @code{track_peak}.
-@section boxblur
+@section resample
-Apply boxblur algorithm to the input video.
+Convert the audio sample format, sample rate and channel layout. This filter is
+not meant to be used directly.
-This filter accepts the following options:
+@section silencedetect
-@table @option
+Detect silence in an audio stream.
-@item luma_radius
-@item luma_power
-@item chroma_radius
-@item chroma_power
-@item alpha_radius
-@item alpha_power
+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.
-@end table
+The printed times and duration are expressed in seconds.
-Chroma and alpha parameters are optional, if not specified they default
-to the corresponding values set for @var{luma_radius} and
-@var{luma_power}.
+The filter accepts the following options:
-@var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
-the radius in pixels of the box used for blurring the corresponding
-input plane. They are expressions, and can contain the following
-constants:
@table @option
-@item w, h
-the input width and height in pixels
+@item duration, d
+Set silence duration until notification (default is 2 seconds).
-@item cw, ch
-the input chroma image width and height in pixels
-
-@item hsub, vsub
-horizontal and vertical chroma subsample values. For example for the
-pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+@item 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.
@end table
-The radius must be a non-negative number, and must not be greater than
-the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
-and of @code{min(cw,ch)/2} for the chroma planes.
-
-@var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
-how many times the boxblur filter is applied to the corresponding
-plane.
-
-Some examples follow:
+@subsection Examples
@itemize
-
@item
-Apply a boxblur filter with luma, chroma, and alpha radius
-set to 2:
+Detect 5 seconds of silence with -50dB noise tolerance:
@example
-boxblur=luma_radius=2:luma_power=1
+silencedetect=n=-50dB:d=5
@end example
@item
-Set luma radius to 2, alpha and chroma radius to 0
+Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
+tolerance in @file{silence.mp3}:
@example
-boxblur=2:1:0:0:0:0
+ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
@end example
+@end itemize
-@item
-Set luma and chroma radius to a fraction of the video dimension
-@example
-boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
-@end example
+@section treble
-@end itemize
+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).
-@section copy
+The filter accepts the following options:
-Copy the input source unchanged to the output. Mainly useful for
-testing purposes.
+@table @option
+@item 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.
+
+@item 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 @code{3000} Hz.
+
+@item width_type
+Set method to specify band-width of filter.
+@table @option
+@item h
+Hz
+@item q
+Q-Factor
+@item o
+octave
+@item s
+slope
+@end table
-@section crop
+@item width, w
+Determine how steep is the filter's shelf transition.
+@end table
-Crop the input video to given dimensions.
+@section volume
-This filter accepts the following options:
+Adjust the input audio volume.
+
+The filter accepts the following options:
@table @option
-@item out_w
-Width of the output video.
+@item volume
+Set audio volume expression.
-@item out_h
-Height of the output video.
+Output values are clipped to the maximum value.
-@item x
-Horizontal position, in the input video, of the left edge of the output video.
+The output audio volume is given by the relation:
+@example
+@var{output_volume} = @var{volume} * @var{input_volume}
+@end example
-@item y
-Vertical position, in the input video, of the top edge of the output video.
+Default value for @var{volume} is "1.0".
-@end table
+@item precision
+Set the mathematical precision.
-The parameters are expressions containing the following constants:
+This determines which input sample formats will be allowed, which affects the
+precision of the volume scaling.
@table @option
-@item E, PI, PHI
-the corresponding mathematical approximated values for e
-(euler number), pi (greek PI), PHI (golden ratio)
+@item fixed
+8-bit fixed-point; limits input sample format to U8, S16, and S32.
+@item float
+32-bit floating-point; limits input sample format to FLT. (default)
+@item double
+64-bit floating-point; limits input sample format to DBL.
+@end table
-@item x, y
-the computed values for @var{x} and @var{y}. They are evaluated for
-each new frame.
+@item eval
+Set when the volume expression is evaluated.
-@item in_w, in_h
-the input width and height
+It accepts the following values:
+@table @samp
+@item once
+only evaluate expression once during the filter initialization, or
+when the @samp{volume} command is sent
-@item iw, ih
-same as @var{in_w} and @var{in_h}
+@item frame
+evaluate expression for each incoming frame
+@end table
-@item out_w, out_h
-the output (cropped) width and height
+Default value is @samp{once}.
+@end table
-@item ow, oh
-same as @var{out_w} and @var{out_h}
+The volume expression can contain the following parameters.
+@table @option
@item n
-the number of input frame, starting from 0
-
+frame number (starting at zero)
+@item nb_channels
+number of channels
+@item nb_consumed_samples
+number of samples consumed by the filter
+@item nb_samples
+number of samples in the current frame
+@item pos
+original frame position in the file
+@item pts
+frame PTS
+@item sample_rate
+sample rate
+@item startpts
+PTS at start of stream
+@item startt
+time at start of stream
@item t
-timestamp expressed in seconds, NAN if the input timestamp is unknown
-
+frame time
+@item tb
+timestamp timebase
+@item volume
+last set volume value
@end table
-The @var{out_w} and @var{out_h} parameters specify the expressions for
-the width and height of the output (cropped) video. They are
-evaluated just at the configuration of the filter.
+Note that when @option{eval} is set to @samp{once} only the
+@var{sample_rate} and @var{tb} variables are available, all other
+variables will evaluate to NAN.
-The default value of @var{out_w} is "in_w", and the default value of
-@var{out_h} is "in_h".
+@subsection Commands
-The expression for @var{out_w} may depend on the value of @var{out_h},
-and the expression for @var{out_h} may depend on @var{out_w}, but they
-cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
-evaluated after @var{out_w} and @var{out_h}.
+This filter supports the following commands:
+@table @option
+@item volume
+Modify the volume expression.
+The command accepts the same syntax of the corresponding option.
-The @var{x} and @var{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.
+If the specified expression is not valid, it is kept at its current
+value.
+@end table
-The default value of @var{x} is "(in_w-out_w)/2", and the default
-value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
-the center of the input image.
+@subsection Examples
-The expression for @var{x} may depend on @var{y}, and the expression
-for @var{y} may depend on @var{x}.
+@itemize
+@item
+Halve the input audio volume:
+@example
+volume=volume=0.5
+volume=volume=1/2
+volume=volume=-6.0206dB
+@end example
-Follow some examples:
+In all the above example the named key for @option{volume} can be
+omitted, for example like in:
@example
-# crop the central input area with size 100x100
-crop=out_w=100:out_h=100
+volume=0.5
+@end example
-# crop the central input area with size 2/3 of the input video
-"crop=out_w=2/3*in_w:out_h=2/3*in_h"
+@item
+Increase input audio power by 6 decibels using fixed-point precision:
+@example
+volume=volume=6dB:precision=fixed
+@end example
-# crop the input video central square
-crop=out_w=in_h
+@item
+Fade volume after time 10 with an annihilation period of 5 seconds:
+@example
+volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
+@end example
+@end itemize
-# 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=out_w=in_w-100:out_h=in_h-100:x=100:y=100
+@section volumedetect
-# crop 10 pixels from the left and right borders, and 20 pixels from
-# the top and bottom borders
-"crop=out_w=in_w-2*10:out_h=in_h-2*20"
+Detect the volume of the input video.
-# keep only the bottom right quarter of the input image
-"crop=out_w=in_w/2:out_h=in_h/2:x=in_w/2:y=in_h/2"
+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.
-# crop height for getting Greek harmony
-"crop=out_w=in_w:out_h=1/PHI*in_w"
+In particular it will show the mean volume (root mean square), maximum
+volume (on a per-sample basis), and the beginning of a histogram of the
+registered volume values (from the maximum value to a cumulated 1/1000 of
+the samples).
-# 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)"
+All volumes are in decibels relative to the maximum PCM value.
-# erratic camera effect depending on timestamp
-"crop=out_w=in_w/2:out_h=in_h/2:x=(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):y=(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
+@subsection Examples
-# set x depending on the value of y
-"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
+Here is an excerpt of the output:
+@example
+[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
@end example
-@section 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.
+It means that:
+@itemize
+@item
+The mean square energy is approximately -27 dB, or 10^-2.7.
+@item
+The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
+@item
+There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
+@end itemize
-This filter accepts the following options:
+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.
-@table @option
+@c man end AUDIO FILTERS
-@item limit
-Threshold, which can be optionally specified from nothing (0) to
-everything (255), defaults to 24.
+@chapter Audio Sources
+@c man begin AUDIO SOURCES
-@item round
-Value which the width/height should be divisible by, defaults to
-16. The offset is automatically adjusted to center the video. Use 2 to
-get only even dimensions (needed for 4:2:2 video). 16 is best when
-encoding to most video codecs.
+Below is a description of the currently available audio sources.
-@item reset
-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. Defaults to 0.
+@section abuffer
-This can be useful when channel logos distort the video area. 0
-indicates never reset and return the largest area encountered during
-playback.
-@end table
+Buffer audio frames, and make them available to the filter chain.
-@section delogo
+This source is mainly intended for a programmatic use, in particular
+through the interface defined in @file{libavfilter/asrc_abuffer.h}.
-Suppress a TV station logo by a simple interpolation of the surrounding
-pixels. Just set a rectangle covering the logo and watch it disappear
-(and sometimes something even uglier appear - your mileage may vary).
+It accepts the following named parameters:
-This filter accepts the following options:
@table @option
-@item x, y
-Specify the top left corner coordinates of the logo. They must be
-specified.
+@item time_base
+Timebase which will be used for timestamps of submitted frames. It must be
+either a floating-point number or in @var{numerator}/@var{denominator} form.
-@item w, h
-Specify the width and height of the logo to clear. They must be
-specified.
+@item sample_rate
+The sample rate of the incoming audio buffers.
-@item band, t
-Specify the thickness of the fuzzy edge of the rectangle (added to
-@var{w} and @var{h}). The default value is 4.
+@item 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 @file{libavutil/samplefmt.h}
-@item show
-When set to 1, a green rectangle is drawn on the screen to simplify
-finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
-@var{band} is set to 4. The default value is 0.
+@item channel_layout
+The channel layout of the incoming audio buffers.
+Either a channel layout name from channel_layout_map in
+@file{libavutil/channel_layout.c} or its corresponding integer representation
+from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
-@end table
+@item channels
+The number of channels of the incoming audio buffers.
+If both @var{channels} and @var{channel_layout} are specified, then they
+must be consistent.
-Some examples follow.
+@end table
-@itemize
+@subsection Examples
-@item
-Set a rectangle covering the area with top left corner coordinates 0,0
-and size 100x77, setting a band of size 10:
@example
-delogo=x=0:y=0:w=100:h=77:band=10
+abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
@end example
-@end itemize
+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:
+@example
+abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
+@end example
-@section drawbox
+@section aevalsrc
-Draw a colored box on the input image.
+Generate an audio signal specified by an expression.
-This filter accepts the following options:
+This source accepts in input one or more expressions (one for each
+channel), which are evaluated and used to generate a corresponding
+audio signal.
-@table @option
+This source accepts the following options:
-@item x, y
-Specify the top left corner coordinates of the box. Default to 0.
+@table @option
+@item exprs
+Set the '|'-separated expressions list for each separate channel. In case the
+@option{channel_layout} option is not specified, the selected channel layout
+depends on the number of provided expressions. Otherwise the last
+specified expression is applied to the remaining output channels.
+
+@item channel_layout, c
+Set the channel layout. The number of channels in the specified layout
+must be equal to the number of specified expressions.
+
+@item duration, d
+Set the minimum duration of the sourced audio. See the function
+@code{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.
-@item width, height
-Specify the width and height of the box, if 0 they are interpreted as
-the input width and height. Default to 0.
+@item nb_samples, n
+Set the number of samples per channel per each output frame,
+default to 1024.
-@item color
-Specify the color of the box to write, it can be the name of a color
-(case insensitive match) or a 0xRRGGBB[AA] sequence.
+@item sample_rate, s
+Specify the sample rate, default to 44100.
@end table
-Follow some examples:
-@example
-# draw a black box around the edge of the input image
-drawbox
+Each expression in @var{exprs} can contain the following constants:
-# draw a box with color red and an opacity of 50%
-drawbox=x=10:y=20:width=200:height=60:color=red@@0.5"
-@end example
+@table @option
+@item n
+number of the evaluated sample, starting from 0
-@section drawtext
+@item t
+time of the evaluated sample expressed in seconds, starting from 0
-Draw text string or text from specified file on top of video using the
-libfreetype library.
+@item s
+sample rate
-To enable compilation of this filter you need to configure Libav with
-@code{--enable-libfreetype}.
+@end table
-The filter also recognizes strftime() sequences in the provided text
-and expands them accordingly. Check the documentation of strftime().
+@subsection Examples
-The description of the accepted parameters follows.
+@itemize
+@item
+Generate silence:
+@example
+aevalsrc=0
+@end example
-@table @option
+@item
+Generate a sin signal with frequency of 440 Hz, set sample rate to
+8000 Hz:
+@example
+aevalsrc="sin(440*2*PI*t):s=8000"
+@end example
-@item fontfile
-The font file to be used for drawing text. Path must be included.
-This parameter is mandatory.
+@item
+Generate a two channels signal, specify the channel layout (Front
+Center + Back Center) explicitly:
+@example
+aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
+@end example
-@item 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
-@var{textfile}.
+@item
+Generate white noise:
+@example
+aevalsrc="-2+random(0)"
+@end example
-@item textfile
-A text file containing text to be drawn. The text must be a sequence
-of UTF-8 encoded characters.
+@item
+Generate an amplitude modulated signal:
+@example
+aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
+@end example
-This parameter is mandatory if no text string is specified with the
-parameter @var{text}.
+@item
+Generate 2.5 Hz binaural beats on a 360 Hz carrier:
+@example
+aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
+@end example
-If both text and textfile are specified, an error is thrown.
+@end itemize
-@item x, y
-The offsets where text will be drawn within the video frame.
-Relative to the top/left border of the output image.
-They accept expressions similar to the @ref{overlay} filter:
-@table @option
+@section anullsrc
-@item x, y
-the computed values for @var{x} and @var{y}. They are evaluated for
-each new frame.
+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).
-@item main_w, main_h
-main input width and height
+This source accepts the following options:
-@item W, H
-same as @var{main_w} and @var{main_h}
+@table @option
-@item text_w, text_h
-rendered text width and height
+@item channel_layout, cl
-@item w, h
-same as @var{text_w} and @var{text_h}
+Specify the channel layout, and can be either an integer or a string
+representing a channel layout. The default value of @var{channel_layout}
+is "stereo".
-@item n
-the number of frames processed, starting from 0
+Check the channel_layout_map definition in
+@file{libavutil/channel_layout.c} for the mapping between strings and
+channel layout values.
-@item t
-timestamp expressed in seconds, NAN if the input timestamp is unknown
+@item sample_rate, r
+Specify the sample rate, and defaults to 44100.
+
+@item nb_samples, n
+Set the number of samples per requested frames.
@end table
-The default value of @var{x} and @var{y} is 0.
+@subsection Examples
-@item fontsize
-The font size to be used for drawing text.
-The default value of @var{fontsize} is 16.
+@itemize
+@item
+Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
+@example
+anullsrc=r=48000:cl=4
+@end example
-@item 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 @var{fontcolor} is "black".
+@item
+Do the same operation with a more obvious syntax:
+@example
+anullsrc=r=48000:cl=mono
+@end example
+@end itemize
-@item 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 @var{boxcolor} is "white".
+All the parameters need to be explicitly defined.
-@item box
-Used to draw a box around text using background color.
-Value should be either 1 (enable) or 0 (disable).
-The default value of @var{box} is 0.
+@section flite
-@item 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".
+Synthesize a voice utterance using the libflite library.
-@item 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 @var{shadowcolor} is "black".
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-libflite}.
-@item ft_load_flags
-Flags to be used for loading the fonts.
+Note that the flite library is not thread-safe.
-The flags map the corresponding flags supported by libfreetype, and are
-a combination of the following values:
-@table @var
-@item default
-@item no_scale
-@item no_hinting
-@item render
-@item no_bitmap
-@item vertical_layout
-@item force_autohint
-@item crop_bitmap
-@item pedantic
-@item ignore_global_advance_width
-@item no_recurse
-@item ignore_transform
-@item monochrome
-@item linear_design
-@item no_autohint
-@item end table
-@end table
+The filter accepts the following options:
-Default value is "render".
+@table @option
-For more information consult the documentation for the FT_LOAD_*
-libfreetype flags.
+@item list_voices
+If set to 1, list the names of the available voices and exit
+immediately. Default value is 0.
-@item tabsize
-The size in number of spaces to use for rendering the tab.
-Default value is 4.
+@item nb_samples, n
+Set the maximum number of samples per frame. Default value is 512.
-@item fix_bounds
-If true, check and fix text coords to avoid clipping.
+@item textfile
+Set the filename containing the text to speak.
+
+@item text
+Set the text to speak.
+
+@item voice, v
+Set the voice to use for the speech synthesis. Default value is
+@code{kal}. See also the @var{list_voices} option.
@end table
-For example the command:
+@subsection Examples
+
+@itemize
+@item
+Read from file @file{speech.txt}, and synthetize the text using the
+standard flite voice:
@example
-drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
+flite=textfile=speech.txt
@end example
-will draw "Test Text" with font FreeSerif, using the default values
-for the optional parameters.
+@item
+Read the specified text selecting the @code{slt} voice:
+@example
+flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
+@end example
-The command:
+@item
+Input text to ffmpeg:
@example
-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"
+ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
@end example
-will 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%.
+@item
+Make @file{ffplay} speak the specified text, using @code{flite} and
+the @code{lavfi} device:
+@example
+ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
+@end example
+@end itemize
-Note that the double quotes are not necessary if spaces are not used
-within the parameter list.
+For more information about libflite, check:
+@url{http://www.speech.cs.cmu.edu/flite/}
-For more information about libfreetype, check:
-@url{http://www.freetype.org/}.
+@section sine
-@section fade
+Generate an audio signal made of a sine wave with amplitude 1/8.
-Apply fade-in/out effect to input video.
+The audio signal is bit-exact.
-This filter accepts the following options:
+The filter accepts the following options:
@table @option
-@item type
-The effect type -- can be either "in" for fade-in, or "out" for a fade-out
-effect.
+@item frequency, f
+Set the carrier frequency. Default is 440 Hz.
-@item start_frame
-The number of the start frame for starting to apply the fade effect.
+@item beep_factor, b
+Enable a periodic beep every second with frequency @var{beep_factor} times
+the carrier frequency. Default is 0, meaning the beep is disabled.
-@item nb_frames
-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.
+@item sample_rate, r
+Specify the sample rate, default is 44100.
-@end table
+@item duration, d
+Specify the duration of the generated audio stream.
-A few usage examples follow, usable too as test scenarios.
-@example
-# fade in first 30 frames of video
-fade=type=in:nb_frames=30
+@item samples_per_frame
+Set the number of samples per output frame, default is 1024.
+@end table
-# fade out last 45 frames of a 200-frame video
-fade=type=out:start_frame=155:nb_frames=45
+@subsection Examples
-# fade in first 25 frames and fade out last 25 frames of a 1000-frame video
-fade=type=in:start_frame=0:nb_frames=25, fade=type=out:start_frame=975:nb_frames=25
+@itemize
-# make first 5 frames black, then fade in from frame 5-24
-fade=type=in:start_frame=5:nb_frames=20
+@item
+Generate a simple 440 Hz sine wave:
+@example
+sine
@end example
-@section fieldorder
+@item
+Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
+@example
+sine=220:4:d=5
+sine=f=220:b=4:d=5
+sine=frequency=220:beep_factor=4:duration=5
+@end example
-Transform the field order of the input video.
+@end itemize
-This filter accepts the following options:
+@c man end AUDIO SOURCES
-@table @option
+@chapter Audio Sinks
+@c man begin AUDIO SINKS
-@item order
-Output field order. Valid values are @var{tff} for top field first or @var{bff}
-for bottom field first.
-@end table
+Below is a description of the currently available audio sinks.
-Default value is "tff".
+@section abuffersink
-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.
+Buffer audio frames, and make them available to the end of filter chain.
-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 sink is mainly intended for programmatic use, in particular
+through the interface defined in @file{libavfilter/buffersink.h}
+or the options system.
-This filter is very useful when converting to or from PAL DV material,
-which is bottom field first.
+It accepts a pointer to an AVABufferSinkContext structure, which
+defines the incoming buffers' formats, to be passed as the opaque
+parameter to @code{avfilter_init_filter} for initialization.
-For example:
-@example
-./avconv -i in.vob -vf "fieldorder=order=bff" out.dv
-@end example
+@section anullsink
-@section fifo
+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.
-Buffer input images and send them when they are requested.
+@c man end AUDIO SINKS
-This filter is mainly useful when auto-inserted by the libavfilter
-framework.
+@chapter Video Filters
+@c man begin VIDEO FILTERS
-The filter does not take parameters.
+When you configure your FFmpeg build, you can disable any of the
+existing filters using @code{--disable-filters}.
+The configure output will show the video filters included in your
+build.
-@section format
+Below is a description of the currently available video filters.
-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.
+@section alphaextract
-This filter accepts the following parameters:
-@table @option
+Extract the alpha component from the input as a grayscale video. This
+is especially useful with the @var{alphamerge} filter.
-@item pix_fmts
-A '|'-separated list of pixel format names, for example
-"pix_fmts=yuv420p|monow|rgb24".
+@section alphamerge
-@end table
+Add or replace the alpha component of the primary input with the
+grayscale value of a second input. This is intended for use with
+@var{alphaextract} to allow the transmission or storage of frame
+sequences that have alpha in a format that doesn't support an alpha
+channel.
-Some examples follow:
+For example, to reconstruct full frames from a normal YUV-encoded video
+and a separate video created with @var{alphaextract}, you might use:
@example
-# 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
+movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
@end example
-@anchor{fps}
-@section fps
+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 @var{overlay} filter instead.
-Convert the video to specified constant framerate by duplicating or dropping
-frames as necessary.
+@section ass
-This filter accepts the following named parameters:
-@table @option
+Same as the @ref{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.
-@item fps
-Desired output framerate.
+@section bbox
-@item start_time
-Assume the first PTS should be the given value, in seconds. This allows for
-padding/trimming at the start of stream. By default, no assumption is made
-about the first frame's expected PTS, so no padding or trimming is done.
-For example, this could be set to 0 to pad the beginning with duplicates of
-the first frame if a video stream starts after the audio stream or to trim any
-frames with a negative PTS.
+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:
+
+@table @option
+@item min_val
+Set the minimal luminance value. Default is @code{16}.
@end table
-@section framepack
+@section blackdetect
-Pack two different video streams into a stereoscopic video, setting proper
-metadata on supported codecs. The two views should have the same size and
-framerate and processing will stop when the shorter video ends. Please note
-that you may conveniently adjust view properties with the @ref{scale} and
-@ref{fps} filters.
+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.
-This filter accepts the following named parameters:
-@table @option
+In order to display the output lines, you need to set the loglevel at
+least to the AV_LOG_INFO value.
-@item format
-Desired packing format. Supported values are:
+The filter accepts the following options:
@table @option
+@item black_min_duration, d
+Set the minimum detected black duration expressed in seconds. It must
+be a non-negative floating point number.
-@item sbs
-Views are next to each other (default).
+Default value is 2.0.
-@item tab
-Views are on top of each other.
+@item picture_black_ratio_th, pic_th
+Set the threshold for considering a picture "black".
+Express the minimum value for the ratio:
+@example
+@var{nb_black_pixels} / @var{nb_pixels}
+@end example
-@item lines
-Views are packed by line.
+for which a picture is considered black.
+Default value is 0.98.
-@item columns
-Views are eacked by column.
+@item pixel_black_th, pix_th
+Set the threshold for considering a pixel "black".
-@item frameseq
-Views are temporally interleaved.
+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:
+@example
+@var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
+@end example
-@end table
+@var{luminance_range_size} and @var{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.
@end table
-Some examples follow:
-
+The following example sets the maximum pixel threshold to the minimum
+value, and detects only black intervals of 2 or more seconds:
@example
-# Convert left and right views into a frame sequential video.
-avconv -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
-
-# Convert views into a side-by-side video with the same output resolution as the input.
-avconv -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT
+blackdetect=d=2:pix_th=0.00
@end example
-@anchor{frei0r}
-@section frei0r
+@section blackframe
-Apply a frei0r effect to the input video.
+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.
-To enable compilation of this filter you need to install the frei0r
-header and configure Libav with --enable-frei0r.
+In order to display the output lines, you need to set the loglevel at
+least to the AV_LOG_INFO value.
-This filter accepts the following options:
+The filter accepts the following options:
@table @option
-@item filter_name
-The name to the frei0r effect to load. If the environment variable
-@env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
-directories specified by the colon separated list in @env{FREIOR_PATH},
-otherwise in the standard frei0r paths, which are in this order:
-@file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
-@file{/usr/lib/frei0r-1/}.
+@item amount
+Set the percentage of the pixels that have to be below the threshold, defaults
+to @code{98}.
-@item filter_params
-A '|'-separated list of parameters to pass to the frei0r effect.
+@item threshold, thresh
+Set the threshold below which a pixel value is considered black, defaults to
+@code{32}.
@end table
-A frei0r effect parameter can be a boolean (whose values are specified
-with "y" and "n"), a double, a color (specified by the syntax
-@var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
-numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
-description), a position (specified by the syntax @var{X}/@var{Y},
-@var{X} and @var{Y} being float numbers) and a string.
+@section blend
-The number and kind of parameters depend on the loaded effect. If an
-effect parameter is not specified the default value is set.
+Blend two video frames into each other.
-Some examples follow:
-@example
-# apply the distort0r effect, set the first two double parameters
-frei0r=filter_name=distort0r:filter_params=0.5|0.01
+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.
-# apply the colordistance effect, takes a color as first parameter
-frei0r=colordistance:0.2/0.3/0.4
-frei0r=colordistance:violet
-frei0r=colordistance:0x112233
+A description of the accepted options follows.
-# apply the perspective effect, specify the top left and top right
-# image positions
-frei0r=perspective:0.2/0.2|0.8/0.2
-@end example
+@table @option
+@item c0_mode
+@item c1_mode
+@item c2_mode
+@item c3_mode
+@item all_mode
+Set blend mode for specific pixel component or all pixel components in case
+of @var{all_mode}. Default value is @code{normal}.
+
+Available values for component modes are:
+@table @samp
+@item addition
+@item and
+@item average
+@item burn
+@item darken
+@item difference
+@item divide
+@item dodge
+@item exclusion
+@item hardlight
+@item lighten
+@item multiply
+@item negation
+@item normal
+@item or
+@item overlay
+@item phoenix
+@item pinlight
+@item reflect
+@item screen
+@item softlight
+@item subtract
+@item vividlight
+@item xor
+@end table
-For more information see:
-@url{http://piksel.org/frei0r}
+@item c0_opacity
+@item c1_opacity
+@item c2_opacity
+@item c3_opacity
+@item all_opacity
+Set blend opacity for specific pixel component or all pixel components in case
+of @var{all_opacity}. Only used in combination with pixel component blend modes.
-@section gradfun
+@item c0_expr
+@item c1_expr
+@item c2_expr
+@item c3_expr
+@item all_expr
+Set blend expression for specific pixel component or all pixel components in case
+of @var{all_expr}. Note that related mode options will be ignored if those are set.
-Fix the banding artifacts that are sometimes introduced into nearly flat
-regions by truncation to 8bit colordepth.
-Interpolate the gradients that should go where the bands are, and
-dither them.
+The expressions can use the following variables:
-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.
+@table @option
+@item N
+The sequential number of the filtered frame, starting from @code{0}.
-This filter accepts the following options:
+@item X
+@item Y
+the coordinates of the current sample
-@table @option
+@item W
+@item H
+the width and height of currently filtered plane
-@item 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.
+@item SW
+@item 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 @code{1,1} for the luma plane, and
+@code{0.5,0.5} for chroma planes.
-@item 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.
+@item T
+Time of the current frame, expressed in seconds.
+
+@item TOP, A
+Value of pixel component at current location for first video frame (top layer).
+@item BOTTOM, B
+Value of pixel component at current location for second video frame (bottom layer).
@end table
+@item shortest
+Force termination when the shortest input terminates. Default is @code{0}.
+@item repeatlast
+Continue applying the last bottom frame after the end of the stream. A value of
+@code{0} disable the filter after the last frame of the bottom layer is reached.
+Default is @code{1}.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Apply transition from bottom layer to top layer in first 10 seconds:
@example
-# default parameters
-gradfun=strength=1.2:radius=16
+blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
+@end example
-# omitting radius
-gradfun=1.2
+@item
+Apply 1x1 checkerboard effect:
+@example
+blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
@end example
-@section hflip
+@item
+Apply uncover left effect:
+@example
+blend=all_expr='if(gte(N*SW+X,W),A,B)'
+@end example
-Flip the input video horizontally.
+@item
+Apply uncover down effect:
+@example
+blend=all_expr='if(gte(Y-N*SH,0),A,B)'
+@end example
-For example to horizontally flip the input video with @command{avconv}:
+@item
+Apply uncover up-left effect:
@example
-avconv -i in.avi -vf "hflip" out.avi
+blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
@end example
+@end itemize
-@section hqdn3d
+@section boxblur
-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.
+Apply boxblur algorithm to the input video.
-It accepts the following optional parameters:
+The filter accepts the following options:
@table @option
-@item luma_spatial
-a non-negative float number which specifies spatial luma strength,
-defaults to 4.0
-
-@item chroma_spatial
-a non-negative float number which specifies spatial chroma strength,
-defaults to 3.0*@var{luma_spatial}/4.0
-@item luma_tmp
-a float number which specifies luma temporal strength, defaults to
-6.0*@var{luma_spatial}/4.0
+@item luma_radius, lr
+@item luma_power, lp
+@item chroma_radius, cr
+@item chroma_power, cp
+@item alpha_radius, ar
+@item alpha_power, ap
-@item chroma_tmp
-a float number which specifies chroma temporal strength, defaults to
-@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
@end table
-@section 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. A vertical lowpass filter
-is always applied in order to avoid twitter effects and reduce moiré patterns.
+A description of the accepted options follows.
-@example
- 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
-@end example
+@table @option
+@item luma_radius, lr
+@item chroma_radius, cr
+@item 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 @code{min(w,h)/2} for the
+luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
+planes.
+
+Default value for @option{luma_radius} is "2". If not specified,
+@option{chroma_radius} and @option{alpha_radius} default to the
+corresponding value set for @option{luma_radius}.
+
+The expressions can contain the following constants:
+@table @option
+@item w
+@item h
+the input width and height in pixels
-It accepts the following optional parameters:
+@item cw
+@item ch
+the input chroma image width and height in pixels
-@table @option
-@item scan
-determines whether the interlaced frame is taken from the even (tff - default)
-or odd (bff) lines of the progressive frame.
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
@end table
-@section 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.
+@item luma_power, lp
+@item chroma_power, cp
+@item alpha_power, ap
+Specify how many times the boxblur filter is applied to the
+corresponding plane.
-@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
-to an RGB input video.
+Default value for @option{luma_power} is 2. If not specified,
+@option{chroma_power} and @option{alpha_power} default to the
+corresponding value set for @option{luma_power}.
-These filters accept the following options:
-@table @option
-@item @var{c0} (first pixel component)
-@item @var{c1} (second pixel component)
-@item @var{c2} (third pixel component)
-@item @var{c3} (fourth pixel component, corresponds to the alpha component)
+A value of 0 will disable the effect.
+@end table
-@item @var{r} (red component)
-@item @var{g} (green component)
-@item @var{b} (blue component)
-@item @var{a} (alpha component)
+@subsection Examples
-@item @var{y} (Y/luminance component)
-@item @var{u} (U/Cb component)
-@item @var{v} (V/Cr component)
-@end table
+@itemize
+@item
+Apply a boxblur filter with luma, chroma, and alpha radius
+set to 2:
+@example
+boxblur=luma_radius=2:luma_power=1
+boxblur=2:1
+@end example
-Each of them specifies the expression to use for computing the lookup table for
-the corresponding pixel component values.
+@item
+Set luma radius to 2, alpha and chroma radius to 0:
+@example
+boxblur=2:1:cr=0:ar=0
+@end example
-The exact component associated to each of the @var{c*} options depends on the
-format in input.
+@item
+Set luma and chroma radius to a fraction of the video dimension:
+@example
+boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
+@end example
+@end itemize
-The @var{lut} filter requires either YUV or RGB pixel formats in input,
-@var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
+@section colorbalance
+Modify intensity of primary colors (red, green and blue) of input frames.
-The expressions can contain the following constants and functions:
+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.
-@table @option
-@item E, PI, PHI
-the corresponding mathematical approximated values for e
-(euler number), pi (greek PI), PHI (golden ratio)
+A positive adjustment value shifts the balance towards the primary color, a negative
+value towards the complementary color.
-@item w, h
-the input width and height
+The filter accepts the following options:
-@item val
-input value for the pixel component
+@table @option
+@item rs
+@item gs
+@item bs
+Adjust red, green and blue shadows (darkest pixels).
+
+@item rm
+@item gm
+@item bm
+Adjust red, green and blue midtones (medium pixels).
+
+@item rh
+@item gh
+@item bh
+Adjust red, green and blue highlights (brightest pixels).
+
+Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
+@end table
-@item clipval
-the input value clipped in the @var{minval}-@var{maxval} range
+@subsection Examples
-@item maxval
-maximum value for the pixel component
+@itemize
+@item
+Add red color cast to shadows:
+@example
+colorbalance=rs=.3
+@end example
+@end itemize
-@item minval
-minimum value for the pixel component
+@section colorchannelmixer
-@item negval
-the negated value for the pixel component value clipped in the
-@var{minval}-@var{maxval} range , it corresponds to the expression
-"maxval-clipval+minval"
+Adjust video input frames by re-mixing color channels.
-@item clip(val)
-the computed value in @var{val} clipped in the
-@var{minval}-@var{maxval} range
+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:
+@example
+@var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
+@end example
-@item gammaval(gamma)
-the computed gamma correction value of the pixel component value
-clipped in the @var{minval}-@var{maxval} range, corresponds to the
-expression
-"pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
+The filter accepts the following options:
+@table @option
+@item rr
+@item rg
+@item rb
+@item ra
+Adjust contribution of input red, green, blue and alpha channels for output red channel.
+Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
+
+@item gr
+@item gg
+@item gb
+@item ga
+Adjust contribution of input red, green, blue and alpha channels for output green channel.
+Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
+
+@item br
+@item bg
+@item bb
+@item ba
+Adjust contribution of input red, green, blue and alpha channels for output blue channel.
+Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
+
+@item ar
+@item ag
+@item ab
+@item aa
+Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
+Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
+
+Allowed ranges for options are @code{[-2.0, 2.0]}.
@end table
-All expressions default to "val".
+@subsection Examples
-Some examples follow:
+@itemize
+@item
+Convert source to grayscale:
@example
-# 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"
+colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
+@end example
+@item
+Simulate sepia tones:
+@example
+colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
+@end example
+@end itemize
-# the above is the same as
-lutrgb="r=negval:g=negval:b=negval"
-lutyuv="y=negval:u=negval:v=negval"
+@section colormatrix
-# negate luminance
-lutyuv=negval
+Convert color matrix.
-# remove chroma components, turns the video into a graytone image
-lutyuv="u=128:v=128"
+The filter accepts the following options:
-# apply a luma burning effect
-lutyuv="y=2*val"
+@table @option
+@item src
+@item dst
+Specify the source and destination color matrix. Both values must be
+specified.
-# remove green and blue components
-lutrgb="g=0:b=0"
+The accepted values are:
+@table @samp
+@item bt709
+BT.709
-# set a constant alpha channel value on input
+@item bt601
+BT.601
+
+@item smpte240m
+SMPTE-240M
+
+@item fcc
+FCC
+@end table
+@end table
+
+For example to convert from BT.601 to SMPTE-240M, use the command:
+@example
+colormatrix=bt601:smpte240m
+@end example
+
+@section copy
+
+Copy the input source unchanged to the output. Mainly useful for
+testing purposes.
+
+@section crop
+
+Crop the input video to given dimensions.
+
+The filter accepts the following options:
+
+@table @option
+@item w, out_w
+Width of the output video. It defaults to @code{iw}.
+This expression is evaluated only once during the filter
+configuration.
+
+@item h, out_h
+Height of the output video. It defaults to @code{ih}.
+This expression is evaluated only once during the filter
+configuration.
+
+@item x
+Horizontal position, in the input video, of the left edge of the output video.
+It defaults to @code{(in_w-out_w)/2}.
+This expression is evaluated per-frame.
+
+@item y
+Vertical position, in the input video, of the top edge of the output video.
+It defaults to @code{(in_h-out_h)/2}.
+This expression is evaluated per-frame.
+
+@item 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.
+@end table
+
+The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
+expressions containing the following constants:
+
+@table @option
+@item x
+@item y
+the computed values for @var{x} and @var{y}. They are evaluated for
+each new frame.
+
+@item in_w
+@item in_h
+the input width and height
+
+@item iw
+@item ih
+same as @var{in_w} and @var{in_h}
+
+@item out_w
+@item out_h
+the output (cropped) width and height
+
+@item ow
+@item oh
+same as @var{out_w} and @var{out_h}
+
+@item a
+same as @var{iw} / @var{ih}
+
+@item sar
+input sample aspect ratio
+
+@item dar
+input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
+@item n
+the number of input frame, starting from 0
+
+@item pos
+the position in the file of the input frame, NAN if unknown
+
+@item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+@end table
+
+The expression for @var{out_w} may depend on the value of @var{out_h},
+and the expression for @var{out_h} may depend on @var{out_w}, but they
+cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
+evaluated after @var{out_w} and @var{out_h}.
+
+The @var{x} and @var{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 @var{x} may depend on @var{y}, and the expression
+for @var{y} may depend on @var{x}.
+
+@subsection Examples
+
+@itemize
+@item
+Crop area with size 100x100 at position (12,34).
+@example
+crop=100:100:12:34
+@end example
+
+Using named options, the example above becomes:
+@example
+crop=w=100:h=100:x=12:y=34
+@end example
+
+@item
+Crop the central input area with size 100x100:
+@example
+crop=100:100
+@end example
+
+@item
+Crop the central input area with size 2/3 of the input video:
+@example
+crop=2/3*in_w:2/3*in_h
+@end example
+
+@item
+Crop the input video central square:
+@example
+crop=out_w=in_h
+crop=in_h
+@end example
+
+@item
+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:
+@example
+crop=in_w-100:in_h-100:100:100
+@end example
+
+@item
+Crop 10 pixels from the left and right borders, and 20 pixels from
+the top and bottom borders
+@example
+crop=in_w-2*10:in_h-2*20
+@end example
+
+@item
+Keep only the bottom right quarter of the input image:
+@example
+crop=in_w/2:in_h/2:in_w/2:in_h/2
+@end example
+
+@item
+Crop height for getting Greek harmony:
+@example
+crop=in_w:1/PHI*in_w
+@end example
+
+@item
+Appply trembling effect:
+@example
+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)
+@end example
+
+@item
+Apply erratic camera effect depending on timestamp:
+@example
+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)"
+@end example
+
+@item
+Set x depending on the value of y:
+@example
+crop=in_w/2:in_h/2:y:10+10*sin(n/10)
+@end example
+@end itemize
+
+@section 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:
+
+@table @option
+
+@item 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.
+
+@item 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.
+
+@item 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.
+@end table
+
+@anchor{curves}
+@section 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 @var{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 @var{(0;0)} and
+@var{(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 @var{x} and @var{y} values must
+be in the @var{[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 @code{x=0}, the filter will automatically
+insert a @var{(0;0)} point. In the same way, if there is no key point defined
+in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
+
+The filter accepts the following options:
+
+@table @option
+@item preset
+Select one of the available color presets. This option can be used in addition
+to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
+options takes priority on the preset values.
+Available presets are:
+@table @samp
+@item none
+@item color_negative
+@item cross_process
+@item darker
+@item increase_contrast
+@item lighter
+@item linear_contrast
+@item medium_contrast
+@item negative
+@item strong_contrast
+@item vintage
+@end table
+Default is @code{none}.
+@item 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
+@option{r}, @option{g}, @option{b} or @option{all} since it acts like a
+post-processing LUT.
+@item red, r
+Set the key points for the red component.
+@item green, g
+Set the key points for the green component.
+@item blue, b
+Set the key points for the blue component.
+@item 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
+@option{all} setting.
+@item psfile
+Specify a Photoshop curves file (@code{.asv}) to import the settings from.
+@end table
+
+To avoid some filtergraph syntax conflicts, each key points list need to be
+defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
+
+@subsection Examples
+
+@itemize
+@item
+Increase slightly the middle level of blue:
+@example
+curves=blue='0.5/0.58'
+@end example
+
+@item
+Vintage effect:
+@example
+curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
+@end example
+Here we obtain the following coordinates for each components:
+@table @var
+@item red
+@code{(0;0.11) (0.42;0.51) (1;0.95)}
+@item green
+@code{(0;0) (0.50;0.48) (1;1)}
+@item blue
+@code{(0;0.22) (0.49;0.44) (1;0.80)}
+@end table
+
+@item
+The previous example can also be achieved with the associated built-in preset:
+@example
+curves=preset=vintage
+@end example
+
+@item
+Or simply:
+@example
+curves=vintage
+@end example
+
+@item
+Use a Photoshop preset and redefine the points of the green component:
+@example
+curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
+@end example
+@end itemize
+
+@section 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:
+
+@table @option
+@item sigma, s
+Set the noise sigma constant.
+
+This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
+coefficient (absolute value) below this threshold with be dropped.
+
+If you need a more advanced filtering, see @option{expr}.
+
+Default is @code{0}.
+
+@item overlap
+Set number overlapping pixels for each block. Each block is of size
+@code{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 @code{15}.
+
+@item 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 @option{sigma} option will be ignored.
+
+The absolute value of the coefficient can be accessed through the @var{c}
+variable.
+@end table
+
+@subsection Examples
+
+Apply a denoise with a @option{sigma} of @code{4.5}:
+@example
+dctdnoiz=4.5
+@end example
+
+The same operation can be achieved using the expression system:
+@example
+dctdnoiz=e='gte(c, 4.5*3)'
+@end example
+
+@anchor{decimate}
+@section decimate
+
+Drop duplicated frames at regular intervals.
+
+The filter accepts the following options:
+
+@table @option
+@item cycle
+Set the number of frames from which one will be dropped. Setting this to
+@var{N} means one frame in every batch of @var{N} frames will be dropped.
+Default is @code{5}.
+
+@item 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 @code{1.1}
+
+@item scthresh
+Set scene change threshold. Default is @code{15}.
+
+@item blockx
+@item 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 @code{32}.
+
+@item 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
+@code{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
+@code{0}.
+
+@item chroma
+Set whether or not chroma is considered in the metric calculations. Default is
+@code{1}.
+@end table
+
+@section dejudder
+
+Remove judder produced by partially interlaced telecined content.
+
+Judder can be introduced, for instance, by @ref{pullup} filter. If the original
+source was partially telecined content then the output of @code{pullup,dejudder}
+will have a variable frame rate. May change the recorded frame rate of the
+container. Aside from that change, this filter will not affect constant frame
+rate video.
+
+The option available in this filter is:
+@table @option
+
+@item cycle
+Specify the length of the window over which the judder repeats.
+
+Accepts any interger greater than 1. Useful values are:
+@table @samp
+
+@item 4
+If the original was telecined from 24 to 30 fps (Film to NTSC).
+
+@item 5
+If the original was telecined from 25 to 30 fps (PAL to NTSC).
+
+@item 20
+If a mixture of the two.
+@end table
+
+The default is @samp{4}.
+@end table
+
+@section 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:
+@table @option
+
+@item x
+@item y
+Specify the top left corner coordinates of the logo. They must be
+specified.
+
+@item w
+@item h
+Specify the width and height of the logo to clear. They must be
+specified.
+
+@item band, t
+Specify the thickness of the fuzzy edge of the rectangle (added to
+@var{w} and @var{h}). The default value is 4.
+
+@item show
+When set to 1, a green rectangle is drawn on the screen to simplify
+finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
+The default value is 0.
+
+The rectangle is drawn on the outermost pixels which will be (partly)
+replaced with interpolated values. The values of the next pixels
+immediately outside this rectangle in each direction will be used to
+compute the interpolated pixel values inside the rectangle.
+
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Set a rectangle covering the area with top left corner coordinates 0,0
+and size 100x77, setting a band of size 10:
+@example
+delogo=x=0:y=0:w=100:h=77:band=10
+@end example
+
+@end itemize
+
+@section 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:
+
+@table @option
+
+@item x
+@item y
+@item w
+@item 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 @var{x}, @var{y}, @var{w} and @var{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.
+
+@item rx
+@item ry
+Specify the maximum extent of movement in x and y directions in the
+range 0-64 pixels. Default 16.
+
+@item edge
+Specify how to generate pixels to fill blanks at the edge of the
+frame. Available values are:
+@table @samp
+@item blank, 0
+Fill zeroes at blank locations
+@item original, 1
+Original image at blank locations
+@item clamp, 2
+Extruded edge value at blank locations
+@item mirror, 3
+Mirrored edge at blank locations
+@end table
+Default value is @samp{mirror}.
+
+@item blocksize
+Specify the blocksize to use for motion search. Range 4-128 pixels,
+default 8.
+
+@item 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.
+
+@item search
+Specify the search strategy. Available values are:
+@table @samp
+@item exhaustive, 0
+Set exhaustive search
+@item less, 1
+Set less exhaustive search.
+@end table
+Default value is @samp{exhaustive}.
+
+@item filename
+If set then a detailed log of the motion search is written to the
+specified file.
+
+@item opencl
+If set to 1, specify using OpenCL capabilities, only available if
+FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
+
+@end table
+
+@section drawbox
+
+Draw a colored box on the input image.
+
+This filter accepts the following options:
+
+@table @option
+@item x
+@item y
+The expressions which specify the top left corner coordinates of the box. Default to 0.
+
+@item width, w
+@item 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.
+
+@item color, c
+Specify the color of the box to write. For the general syntax of this option,
+check the "Color" section in the ffmpeg-utils manual. If the special
+value @code{invert} is used, the box edge color is the same as the
+video with inverted luma.
+
+@item thickness, t
+The expression which sets the thickness of the box edge. Default value is @code{3}.
+
+See below for the list of accepted constants.
+@end table
+
+The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
+following constants:
+
+@table @option
+@item dar
+The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
+@item in_h, ih
+@item in_w, iw
+The input width and height.
+
+@item sar
+The input sample aspect ratio.
+
+@item x
+@item y
+The x and y offset coordinates where the box is drawn.
+
+@item w
+@item h
+The width and height of the drawn box.
+
+@item t
+The thickness of the drawn box.
+
+These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
+each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
+
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Draw a black box around the edge of the input image:
+@example
+drawbox
+@end example
+
+@item
+Draw a box with color red and an opacity of 50%:
+@example
+drawbox=10:20:200:60:red@@0.5
+@end example
+
+The previous example can be specified as:
+@example
+drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
+@end example
+
+@item
+Fill the box with pink color:
+@example
+drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
+@end example
+
+@item
+Draw a 2-pixel red 2.40:1 mask:
+@example
+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
+@end example
+@end itemize
+
+@section drawgrid
+
+Draw a grid on the input image.
+
+This filter accepts the following options:
+
+@table @option
+@item x
+@item y
+The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
+
+@item width, w
+@item 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 @code{thickness}, so image gets
+framed. Default to 0.
+
+@item color, c
+Specify the color of the grid. For the general syntax of this option,
+check the "Color" section in the ffmpeg-utils manual. If the special
+value @code{invert} is used, the grid color is the same as the
+video with inverted luma.
+
+@item thickness, t
+The expression which sets the thickness of the grid line. Default value is @code{1}.
+
+See below for the list of accepted constants.
+@end table
+
+The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
+following constants:
+
+@table @option
+@item dar
+The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
+@item in_h, ih
+@item in_w, iw
+The input grid cell width and height.
+
+@item sar
+The input sample aspect ratio.
+
+@item x
+@item y
+The x and y coordinates of some point of grid intersection (meant to configure offset).
+
+@item w
+@item h
+The width and height of the drawn cell.
+
+@item t
+The thickness of the drawn cell.
+
+These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
+each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
+
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
+@example
+drawgrid=width=100:height=100:thickness=2:color=red@@0.5
+@end example
+
+@item
+Draw a white 3x3 grid with an opacity of 50%:
+@example
+drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
+@end example
+@end itemize
+
+@anchor{drawtext}
+@section 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
+@code{--enable-libfreetype}.
+
+@subsection Syntax
+
+The description of the accepted parameters follows.
+
+@table @option
+
+@item box
+Used to draw a box around text using background color.
+Value should be either 1 (enable) or 0 (disable).
+The default value of @var{box} is 0.
+
+@item boxcolor
+The color to be used for drawing box around text. For the syntax of this
+option, check the "Color" section in the ffmpeg-utils manual.
+
+The default value of @var{boxcolor} is "white".
+
+@item borderw
+Set the width of the border to be drawn around the text using @var{bordercolor}.
+The default value of @var{borderw} is 0.
+
+@item bordercolor
+Set the color to be used for drawing border around text. For the syntax of this
+option, check the "Color" section in the ffmpeg-utils manual.
+
+The default value of @var{bordercolor} is "black".
+
+@item expansion
+Select how the @var{text} is expanded. Can be either @code{none},
+@code{strftime} (deprecated) or
+@code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
+below for details.
+
+@item fix_bounds
+If true, check and fix text coords to avoid clipping.
+
+@item fontcolor
+The color to be used for drawing fonts. For the syntax of this option, check
+the "Color" section in the ffmpeg-utils manual.
+
+The default value of @var{fontcolor} is "black".
+
+@item fontfile
+The font file to be used for drawing text. Path must be included.
+This parameter is mandatory.
+
+@item fontsize
+The font size to be used for drawing text.
+The default value of @var{fontsize} is 16.
+
+@item 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:
+@table @var
+@item default
+@item no_scale
+@item no_hinting
+@item render
+@item no_bitmap
+@item vertical_layout
+@item force_autohint
+@item crop_bitmap
+@item pedantic
+@item ignore_global_advance_width
+@item no_recurse
+@item ignore_transform
+@item monochrome
+@item linear_design
+@item no_autohint
+@end table
+
+Default value is "default".
+
+For more information consult the documentation for the FT_LOAD_*
+libfreetype flags.
+
+@item shadowcolor
+The color to be used for drawing a shadow behind the drawn text. For the
+syntax of this option, check the "Color" section in the ffmpeg-utils manual.
+
+The default value of @var{shadowcolor} is "black".
+
+@item shadowx
+@item 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".
+
+@item start_number
+The starting frame number for the n/frame_num variable. The default value
+is "0".
+
+@item tabsize
+The size in number of spaces to use for rendering the tab.
+Default value is 4.
+
+@item timecode
+Set the initial timecode representation in "hh:mm:ss[:;.]ff"
+format. It can be used with or without text parameter. @var{timecode_rate}
+option must be specified.
+
+@item timecode_rate, rate, r
+Set the timecode frame rate (timecode only).
+
+@item 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
+@var{textfile}.
+
+@item 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 @var{text}.
+
+If both @var{text} and @var{textfile} are specified, an error is thrown.
+
+@item reload
+If set to 1, the @var{textfile} will be reloaded before each frame.
+Be sure to update it atomically, or it may be read partially, or even fail.
+
+@item x
+@item 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 @var{x} and @var{y} is "0".
+
+See below for the list of accepted constants and functions.
+@end table
+
+The parameters for @var{x} and @var{y} are expressions containing the
+following constants and functions:
+
+@table @option
+@item dar
+input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
+@item line_h, lh
+the height of each text line
+
+@item main_h, h, H
+the input height
+
+@item main_w, w, W
+the input width
+
+@item 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.
+
+@item 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.
+
+@item max_glyph_h
+maximum glyph height, that is the maximum height for all the glyphs
+contained in the rendered text, it is equivalent to @var{ascent} -
+@var{descent}.
+
+@item max_glyph_w
+maximum glyph width, that is the maximum width for all the glyphs
+contained in the rendered text
+
+@item n
+the number of input frame, starting from 0
+
+@item rand(min, max)
+return a random number included between @var{min} and @var{max}
+
+@item sar
+input sample aspect ratio
+
+@item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+@item text_h, th
+the height of the rendered text
+
+@item text_w, tw
+the width of the rendered text
+
+@item x
+@item y
+the x and y offset coordinates where the text is drawn.
+
+These parameters allow the @var{x} and @var{y} expressions to refer
+each other, so you can for example specify @code{y=x/dar}.
+@end table
+
+If libavfilter was built with @code{--enable-fontconfig}, then
+@option{fontfile} can be a fontconfig pattern or omitted.
+
+@anchor{drawtext_expansion}
+@subsection Text expansion
+
+If @option{expansion} is set to @code{strftime},
+the filter recognizes strftime() sequences in the provided text and
+expands them accordingly. Check the documentation of strftime(). This
+feature is deprecated.
+
+If @option{expansion} is set to @code{none}, the text is printed verbatim.
+
+If @option{expansion} is set to @code{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 @code{%@{...@}} 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
+@option{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:
+
+@table @command
+
+@item 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 @var{x} and
+@var{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 @var{text_w} and @var{text_h} will have an undefined
+value.
+
+@item gmtime
+The time at which the filter is running, expressed in UTC.
+It can accept an argument: a strftime() format string.
+
+@item localtime
+The time at which the filter is running, expressed in the local time zone.
+It can accept an argument: a strftime() format string.
+
+@item metadata
+Frame metadata. It must take one argument specifying metadata key.
+
+@item n, frame_num
+The frame number, starting from 0.
+
+@item pict_type
+A 1 character description of the current picture type.
+
+@item pts
+The timestamp of the current frame, in seconds, with microsecond accuracy.
+
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Draw "Test Text" with font FreeSerif, using the default values for the
+optional parameters.
+
+@example
+drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
+@end example
+
+@item
+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%.
+
+@example
+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"
+@end example
+
+Note that the double quotes are not necessary if spaces are not used
+within the parameter list.
+
+@item
+Show the text at the center of the video frame:
+@example
+drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
+@end example
+
+@item
+Show a text line sliding from right to left in the last row of the video
+frame. The file @file{LONG_LINE} is assumed to contain a single line
+with no newlines.
+@example
+drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
+@end example
+
+@item
+Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
+@example
+drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
+@end example
+
+@item
+Draw a single green letter "g", at the center of the input video.
+The glyph baseline is placed at half screen height.
+@example
+drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
+@end example
+
+@item
+Show text for 1 second every 3 seconds:
+@example
+drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
+@end example
+
+@item
+Use fontconfig to set the font. Note that the colons need to be escaped.
+@example
+drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
+@end example
+
+@item
+Print the date of a real-time encoding (see strftime(3)):
+@example
+drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
+@end example
+
+@end itemize
+
+For more information about libfreetype, check:
+@url{http://www.freetype.org/}.
+
+For more information about fontconfig, check:
+@url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
+
+@section edgedetect
+
+Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
+
+The filter accepts the following options:
+
+@table @option
+@item low
+@item 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.
+
+@var{low} and @var{high} threshold values must be choosen in the range
+[0,1], and @var{low} should be lesser or equal to @var{high}.
+
+Default value for @var{low} is @code{20/255}, and default value for @var{high}
+is @code{50/255}.
+@end table
+
+Example:
+@example
+edgedetect=low=0.1:high=0.4
+@end example
+
+@section extractplanes
+
+Extract color channel components from input video stream into
+separate grayscale video streams.
+
+The filter accepts the following option:
+
+@table @option
+@item planes
+Set plane(s) to extract.
+
+Available values for planes are:
+@table @samp
+@item y
+@item u
+@item v
+@item a
+@item r
+@item g
+@item b
+@end table
+
+Choosing planes not available in the input will result in an error.
+That means you cannot select @code{r}, @code{g}, @code{b} planes
+with @code{y}, @code{u}, @code{v} planes at same time.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Extract luma, u and v color channel component from input video frame
+into 3 grayscale outputs:
+@example
+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
+@end example
+@end itemize
+
+@section elbg
+
+Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
+
+For each input image, the filter will compute the optimal mapping from
+the input to the output given the codebook length, that is the number
+of distinct output colors.
+
+This filter accepts the following options.
+
+@table @option
+@item codebook_length, l
+Set codebook length. The value must be a positive integer, and
+represents the number of distinct output colors. Default value is 256.
+
+@item nb_steps, n
+Set the maximum number of iterations to apply for computing the optimal
+mapping. The higher the value the better the result and the higher the
+computation time. Default value is 1.
+
+@item seed, s
+Set a random seed, must be an integer included between 0 and
+UINT32_MAX. If not specified, or if explicitly set to -1, the filter
+will try to use a good random seed on a best effort basis.
+@end table
+
+@section fade
+
+Apply fade-in/out effect to input video.
+
+This filter accepts the following options:
+
+@table @option
+@item type, t
+The effect type -- can be either "in" for fade-in, or "out" for a fade-out
+effect.
+Default is @code{in}.
+
+@item start_frame, s
+Specify the number of the start frame for starting to apply the fade
+effect. Default is 0.
+
+@item 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 filled with the
+selected @option{color}.
+Default is 25.
+
+@item alpha
+If set to 1, fade only alpha channel, if one exists on the input.
+Default value is 0.
+
+@item 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.
+
+@item duration, d
+The number of seconds for which the fade effect has to last. At the end of the
+fade-in effect the output video will have the same intensity as the input video,
+at the end of the fade-out transition the output video will be filled with the
+selected @option{color}.
+If both duration and nb_frames are specified, duration is used. Default is 0.
+
+@item color, c
+Specify the color of the fade. Default is "black".
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Fade in first 30 frames of video:
+@example
+fade=in:0:30
+@end example
+
+The command above is equivalent to:
+@example
+fade=t=in:s=0:n=30
+@end example
+
+@item
+Fade out last 45 frames of a 200-frame video:
+@example
+fade=out:155:45
+fade=type=out:start_frame=155:nb_frames=45
+@end example
+
+@item
+Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
+@example
+fade=in:0:25, fade=out:975:25
+@end example
+
+@item
+Make first 5 frames yellow, then fade in from frame 5-24:
+@example
+fade=in:5:20:color=yellow
+@end example
+
+@item
+Fade in alpha over first 25 frames of video:
+@example
+fade=in:0:25:alpha=1
+@end example
+
+@item
+Make first 5.5 seconds black, then fade in for 0.5 seconds:
+@example
+fade=t=in:st=5.5:d=0.5
+@end example
+
+@end itemize
+
+@section 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:
+
+@table @option
+@item type
+Specify whether to extract the top (if the value is @code{0} or
+@code{top}) or the bottom field (if the value is @code{1} or
+@code{bottom}).
+@end table
+
+@section 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 @code{fieldmatch} needs to be
+followed by a decimation filter such as @ref{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,
+@code{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 @ref{yadif} before decimation.
+
+In addition to the various configuration options, @code{fieldmatch} can take an
+optional second stream, activated through the @option{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 @code{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:
+
+@table @option
+@item order
+Specify the assumed field order of the input stream. Available values are:
+
+@table @samp
+@item auto
+Auto detect parity (use FFmpeg's internal parity value).
+@item bff
+Assume bottom field first.
+@item tff
+Assume top field first.
+@end table
+
+Note that it is sometimes recommended not to trust the parity announced by the
+stream.
+
+Default value is @var{auto}.
+
+@item mode
+Set the matching mode or strategy to use. @option{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, @option{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 @option{pc} and @option{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 @ref{p/c/n/u/b meaning} section.
+
+Available values are:
+
+@table @samp
+@item pc
+2-way matching (p/c)
+@item pc_n
+2-way matching, and trying 3rd match if still combed (p/c + n)
+@item pc_u
+2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
+@item 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)
+@item pcn
+3-way matching (p/c/n)
+@item 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)
+@end table
+
+The parenthesis at the end indicate the matches that would be used for that
+mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
+@var{top}).
+
+In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
+the slowest.
+
+Default value is @var{pc_n}.
+
+@item 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 @option{clip2} feature from
+VFM/TFM.
+
+Default value is @code{0} (disabled).
+
+@item field
+Set the field to match from. It is recommended to set this to the same value as
+@option{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:
+
+@table @samp
+@item auto
+Automatic (same value as @option{order}).
+@item bottom
+Match from the bottom field.
+@item top
+Match from the top field.
+@end table
+
+Default value is @var{auto}.
+
+@item 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 @code{0}
+only if your clip has bad chroma problems such as heavy rainbowing or other
+artifacts. Setting this to @code{0} could also be used to speed things up at
+the cost of some accuracy.
+
+Default value is @code{1}.
+
+@item y0
+@item y1
+These define an exclusion band which excludes the lines between @option{y0} and
+@option{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. @option{y0} sets the starting scan line and
+@option{y1} sets the ending line; all lines in between @option{y0} and
+@option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
+@option{y0} and @option{y1} to the same value will disable the feature.
+@option{y0} and @option{y1} defaults to @code{0}.
+
+@item scthresh
+Set the scene change detection threshold as a percentage of maximum change on
+the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
+detection is only relevant in case @option{combmatch}=@var{sc}. The range for
+@option{scthresh} is @code{[0.0, 100.0]}.
+
+Default value is @code{12.0}.
+
+@item combmatch
+When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
+account the combed scores of matches when deciding what match to use as the
+final match. Available values are:
+
+@table @samp
+@item none
+No final matching based on combed scores.
+@item sc
+Combed scores are only used when a scene change is detected.
+@item full
+Use combed scores all the time.
+@end table
+
+Default is @var{sc}.
+
+@item combdbg
+Force @code{fieldmatch} to calculate the combed metrics for certain matches and
+print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
+Available values are:
+
+@table @samp
+@item none
+No forced calculation.
+@item pcn
+Force p/c/n calculations.
+@item pcnub
+Force p/c/n/u/b calculations.
+@end table
+
+Default value is @var{none}.
+
+@item 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
+@code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
+be detected as combed). This is basically a pixel difference value. A good
+range is @code{[8, 12]}.
+
+Default value is @code{9}.
+
+@item 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 @option{chroma}=@var{0} is usually more reliable, except for the case
+where there is chroma only combing in the source.
+
+Default value is @code{0}.
+
+@item blockx
+@item 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
+@option{combpel} pixels are required to be detected as combed for a frame to be
+declared combed. See the @option{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 @code{16}.
+
+@item combpel
+The number of combed pixels inside any of the @option{blocky} by
+@option{blockx} size blocks on the frame for the frame to be detected as
+combed. While @option{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 @option{blockx} and @option{blocky} settings) on the
+frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
+which point no frames will ever be detected as combed). This setting is known
+as @option{MI} in TFM/VFM vocabulary.
+
+Default value is @code{80}.
+@end table
+
+@anchor{p/c/n/u/b meaning}
+@subsection p/c/n/u/b meaning
+
+@subsubsection p/c/n
+
+We assume the following telecined stream:
+
+@example
+Top fields: 1 2 2 3 4
+Bottom fields: 1 2 3 4 4
+@end example
+
+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 @code{fieldmatch} is configured to run a matching from bottom
+(@option{field}=@var{bottom}) this is how this input stream get transformed:
+
+@example
+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
+@end example
+
+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 @ref{decimate} filter.
+
+The same operation now matching from top fields (@option{field}=@var{top})
+looks like this:
+
+@example
+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
+@end example
+
+In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
+basically, they refer to the frame and field of the opposite parity:
+
+@itemize
+@item @var{p} matches the field of the opposite parity in the previous frame
+@item @var{c} matches the field of the opposite parity in the current frame
+@item @var{n} matches the field of the opposite parity in the next frame
+@end itemize
+
+@subsubsection u/b
+
+The @var{u} and @var{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 (@option{field}=@var{bottom}):
+@example
+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
+@end example
+
+With top matching (@option{field}=@var{top}):
+@example
+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
+@end example
+
+@subsection Examples
+
+Simple IVTC of a top field first telecined stream:
+@example
+fieldmatch=order=tff:combmatch=none, decimate
+@end example
+
+Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
+@example
+fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
+@end example
+
+@section fieldorder
+
+Transform the field order of the input video.
+
+This filter accepts the following options:
+
+@table @option
+
+@item order
+Output field order. Valid values are @var{tff} for top field first or @var{bff}
+for bottom field first.
+@end table
+
+Default value is @samp{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:
+@example
+ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
+@end example
+
+@section 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.
+
+@anchor{format}
+@section 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:
+@table @option
+
+@item pix_fmts
+A '|'-separated list of pixel format names, for example
+"pix_fmts=yuv420p|monow|rgb24".
+
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Convert the input video to the format @var{yuv420p}
+@example
+format=pix_fmts=yuv420p
+@end example
+
+Convert the input video to any of the formats in the list
+@example
+format=pix_fmts=yuv420p|yuv444p|yuv410p
+@end example
+@end itemize
+
+@anchor{fps}
+@section fps
+
+Convert the video to specified constant frame rate by duplicating or dropping
+frames as necessary.
+
+This filter accepts the following named parameters:
+@table @option
+
+@item fps
+Desired output frame rate. The default is @code{25}.
+
+@item round
+Rounding method.
+
+Possible values are:
+@table @option
+@item zero
+zero round towards 0
+@item inf
+round away from 0
+@item down
+round towards -infinity
+@item up
+round towards +infinity
+@item near
+round to nearest
+@end table
+The default is @code{near}.
+
+@item start_time
+Assume the first PTS should be the given value, in seconds. This allows for
+padding/trimming at the start of stream. By default, no assumption is made
+about the first frame's expected PTS, so no padding or trimming is done.
+For example, this could be set to 0 to pad the beginning with duplicates of
+the first frame if a video stream starts after the audio stream or to trim any
+frames with a negative PTS.
+
+@end table
+
+Alternatively, the options can be specified as a flat string:
+@var{fps}[:@var{round}].
+
+See also the @ref{setpts} filter.
+
+@subsection Examples
+
+@itemize
+@item
+A typical usage in order to set the fps to 25:
+@example
+fps=fps=25
+@end example
+
+@item
+Sets the fps to 24, using abbreviation and rounding method to round to nearest:
+@example
+fps=fps=film:round=near
+@end example
+@end itemize
+
+@section framepack
+
+Pack two different video streams into a stereoscopic video, setting proper
+metadata on supported codecs. The two views should have the same size and
+framerate and processing will stop when the shorter video ends. Please note
+that you may conveniently adjust view properties with the @ref{scale} and
+@ref{fps} filters.
+
+This filter accepts the following named parameters:
+@table @option
+
+@item format
+Desired packing format. Supported values are:
+
+@table @option
+
+@item sbs
+Views are next to each other (default).
+
+@item tab
+Views are on top of each other.
+
+@item lines
+Views are packed by line.
+
+@item columns
+Views are eacked by column.
+
+@item frameseq
+Views are temporally interleaved.
+
+@end table
+
+@end table
+
+Some examples follow:
+
+@example
+# Convert left and right views into a frame sequential video.
+ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
+
+# Convert views into a side-by-side video with the same output resolution as the input.
+ffmpeg -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT
+@end example
+
+@section framestep
+
+Select one frame every N-th frame.
+
+This filter accepts the following option:
+@table @option
+@item step
+Select frame after every @code{step} frames.
+Allowed values are positive integers higher than 0. Default value is @code{1}.
+@end table
+
+@anchor{frei0r}
+@section 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 @code{--enable-frei0r}.
+
+This filter accepts the following options:
+
+@table @option
+
+@item filter_name
+The name to the frei0r effect to load. If the environment variable
+@env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
+directories specified by the colon separated list in @env{FREIOR_PATH},
+otherwise in the standard frei0r paths, which are in this order:
+@file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
+@file{/usr/lib/frei0r-1/}.
+
+@item filter_params
+A '|'-separated list of parameters to pass to the frei0r effect.
+
+@end table
+
+A frei0r effect parameter can be a boolean (whose values are specified
+with "y" and "n"), a double, a color (specified by the syntax
+@var{R}/@var{G}/@var{B}, (@var{R}, @var{G}, and @var{B} being float
+numbers from 0.0 to 1.0) or by a color description specified in the "Color"
+section in the ffmpeg-utils manual), a position (specified by the syntax @var{X}/@var{Y},
+@var{X} and @var{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.
+
+@subsection Examples
+
+@itemize
+@item
+Apply the distort0r effect, set the first two double parameters:
+@example
+frei0r=filter_name=distort0r:filter_params=0.5|0.01
+@end example
+
+@item
+Apply the colordistance effect, take a color as first parameter:
+@example
+frei0r=colordistance:0.2/0.3/0.4
+frei0r=colordistance:violet
+frei0r=colordistance:0x112233
+@end example
+
+@item
+Apply the perspective effect, specify the top left and top right image
+positions:
+@example
+frei0r=perspective:0.2/0.2|0.8/0.2
+@end example
+@end itemize
+
+For more information see:
+@url{http://frei0r.dyne.org}
+
+@section geq
+
+The filter accepts the following options:
+
+@table @option
+@item lum_expr, lum
+Set the luminance expression.
+@item cb_expr, cb
+Set the chrominance blue expression.
+@item cr_expr, cr
+Set the chrominance red expression.
+@item alpha_expr, a
+Set the alpha expression.
+@item red_expr, r
+Set the red expression.
+@item green_expr, g
+Set the green expression.
+@item blue_expr, b
+Set the blue expression.
+@end table
+
+The colorspace is selected according to the specified options. If one
+of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
+options is specified, the filter will automatically select a YCbCr
+colorspace. If one of the @option{red_expr}, @option{green_expr}, or
+@option{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:
+
+@table @option
+@item N
+The sequential number of the filtered frame, starting from @code{0}.
+
+@item X
+@item Y
+The coordinates of the current sample.
+
+@item W
+@item H
+The width and height of the image.
+
+@item SW
+@item 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 @code{1,1} for the luma plane, and
+@code{0.5,0.5} for chroma planes.
+
+@item T
+Time of the current frame, expressed in seconds.
+
+@item p(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the current
+plane.
+
+@item lum(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the luminance
+plane.
+
+@item cb(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the
+blue-difference chroma plane. Return 0 if there is no such plane.
+
+@item cr(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the
+red-difference chroma plane. Return 0 if there is no such plane.
+
+@item r(x, y)
+@item g(x, y)
+@item b(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the
+red/green/blue component. Return 0 if there is no such component.
+
+@item alpha(x, y)
+Return the value of the pixel at location (@var{x},@var{y}) of the alpha
+plane. Return 0 if there is no such plane.
+@end table
+
+For functions, if @var{x} and @var{y} are outside the area, the value will be
+automatically clipped to the closer edge.
+
+@subsection Examples
+
+@itemize
+@item
+Flip the image horizontally:
+@example
+geq=p(W-X\,Y)
+@end example
+
+@item
+Generate a bidimensional sine wave, with angle @code{PI/3} and a
+wavelength of 100 pixels:
+@example
+geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
+@end example
+
+@item
+Generate a fancy enigmatic moving light:
+@example
+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
+@end example
+
+@item
+Generate a quick emboss effect:
+@example
+format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
+@end example
+
+@item
+Modify RGB components depending on pixel position:
+@example
+geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
+@end example
+@end itemize
+
+@section 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:
+
+@table @option
+
+@item 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.
+
+@item 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.
+
+@end table
+
+Alternatively, the options can be specified as a flat string:
+@var{strength}[:@var{radius}]
+
+@subsection Examples
+
+@itemize
+@item
+Apply the filter with a @code{3.5} strength and radius of @code{8}:
+@example
+gradfun=3.5:8
+@end example
+
+@item
+Specify radius, omitting the strength (which will fall-back to the default
+value):
+@example
+gradfun=radius=8
+@end example
+
+@end itemize
+
+@anchor{haldclut}
+@section 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:
+
+@table @option
+@item shortest
+Force termination when the shortest input terminates. Default is @code{0}.
+@item repeatlast
+Continue applying the last CLUT after the end of the stream. A value of
+@code{0} disable the filter after the last frame of the CLUT is reached.
+Default is @code{1}.
+@end table
+
+@code{haldclut} also has the same interpolation options as @ref{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 @url{http://www.quelsolaar.com/technology/clut.html}.
+
+@subsection Workflow examples
+
+@subsubsection Hald CLUT video stream
+
+Generate an identity Hald CLUT stream altered with various effects:
+@example
+ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process" -t 10 -c:v ffv1 clut.nut
+@end example
+
+Note: make sure you use a lossless codec.
+
+Then use it with @code{haldclut} to apply it on some random stream:
+@example
+ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
+@end example
+
+The Hald CLUT will be applied to the 10 first seconds (duration of
+@file{clut.nut}), then the latest picture of that CLUT stream will be applied
+to the remaining frames of the @code{mandelbrot} stream.
+
+@subsubsection Hald CLUT with preview
+
+A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
+@code{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
+@code{haldclut} filter:
+
+@example
+ffmpeg -f lavfi -i @ref{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
+@end example
+
+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:
+@example
+ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
+@end example
+
+@section hflip
+
+Flip the input video horizontally.
+
+For example to horizontally flip the input video with @command{ffmpeg}:
+@example
+ffmpeg -i in.avi -vf "hflip" out.avi
+@end example
+
+@section 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:
+
+@table @option
+@item 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.
+
+@item 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.
+
+@item 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 @code{none}, @code{weak} or
+@code{strong}. It defaults to @code{none}.
+@end table
+
+@section histogram
+
+Compute and draw a color distribution histogram for the input video.
+
+The computed histogram is a representation of the color component
+distribution in an image.
+
+The filter accepts the following options:
+
+@table @option
+@item mode
+Set histogram mode.
+
+It accepts the following values:
+@table @samp
+@item levels
+Standard histogram that displays the color components distribution in an
+image. Displays color graph for each color component. Shows distribution of
+the Y, U, V, A or R, G, B components, depending on input format, in the
+current frame. Below each graph a color component scale meter is shown.
+
+@item color
+Displays chroma values (U/V color placement) in a two dimensional
+graph (which is called a vectorscope). The brighter a pixel in the
+vectorscope, the more pixels of the input frame correspond to that pixel
+(i.e., 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. The graph can therefore be used to read 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 the amount of a specific color is increased (while leaving the other
+colors unchanged) the saturation increases, and the indicator moves towards
+the edge of the square.
+
+@item color2
+Chroma values in vectorscope, similar as @code{color} but actual chroma values
+are displayed.
+
+@item waveform
+Per row/column color component graph. In row mode, the graph on the left side
+represents color component value 0 and the right side represents value = 255.
+In column mode, the top side represents color component value = 0 and bottom
+side represents value = 255.
+@end table
+Default value is @code{levels}.
+
+@item level_height
+Set height of level in @code{levels}. Default value is @code{200}.
+Allowed range is [50, 2048].
+
+@item scale_height
+Set height of color scale in @code{levels}. Default value is @code{12}.
+Allowed range is [0, 40].
+
+@item step
+Set step for @code{waveform} mode. Smaller values are useful to find out how
+many values of the same luminance are distributed across input rows/columns.
+Default value is @code{10}. Allowed range is [1, 255].
+
+@item waveform_mode
+Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
+Default is @code{row}.
+
+@item waveform_mirror
+Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
+means mirrored. In mirrored mode, higher values will be represented on the left
+side for @code{row} mode and at the top for @code{column} mode. Default is
+@code{0} (unmirrored).
+
+@item display_mode
+Set display mode for @code{waveform} and @code{levels}.
+It accepts the following values:
+@table @samp
+@item parade
+Display separate graph for the color components side by side in
+@code{row} waveform mode or one below the other in @code{column} waveform mode
+for @code{waveform} histogram mode. For @code{levels} histogram mode,
+per color component graphs are placed below each other.
+
+Using this display mode in @code{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 graphs of each waveform. Since whites,
+grays, and blacks are characterized by exactly equal amounts of red, green,
+and blue, neutral areas of the picture should display three waveforms of
+roughly equal width/height. If not, the correction is easy to perform by
+making level adjustments the three waveforms.
+
+@item overlay
+Presents information identical to that in the @code{parade}, except
+that the graphs representing color components are superimposed directly
+over one another.
+
+This display mode in @code{waveform} histogram mode makes it easier to spot
+relative differences or similarities in overlapping areas of the color
+components that are supposed to be identical, such as neutral whites, grays,
+or blacks.
+@end table
+Default is @code{parade}.
+
+@item levels_mode
+Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
+Default is @code{linear}.
+@end table
+
+@subsection Examples
+
+@itemize
+
+@item
+Calculate and draw histogram:
+@example
+ffplay -i input -vf histogram
+@end example
+
+@end itemize
+
+@anchor{hqdn3d}
+@section 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:
+
+@table @option
+@item luma_spatial
+a non-negative float number which specifies spatial luma strength,
+defaults to 4.0
+
+@item chroma_spatial
+a non-negative float number which specifies spatial chroma strength,
+defaults to 3.0*@var{luma_spatial}/4.0
+
+@item luma_tmp
+a float number which specifies luma temporal strength, defaults to
+6.0*@var{luma_spatial}/4.0
+
+@item chroma_tmp
+a float number which specifies chroma temporal strength, defaults to
+@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
+@end table
+
+@section hue
+
+Modify the hue and/or the saturation of the input.
+
+This filter accepts the following options:
+
+@table @option
+@item h
+Specify the hue angle as a number of degrees. It accepts an expression,
+and defaults to "0".
+
+@item s
+Specify the saturation in the [-10,10] range. It accepts an expression and
+defaults to "1".
+
+@item H
+Specify the hue angle as a number of radians. It accepts an
+expression, and defaults to "0".
+
+@item b
+Specify the brightness in the [-10,10] range. It accepts an expression and
+defaults to "0".
+@end table
+
+@option{h} and @option{H} are mutually exclusive, and can't be
+specified at the same time.
+
+The @option{b}, @option{h}, @option{H} and @option{s} option values are
+expressions containing the following constants:
+
+@table @option
+@item n
+frame count of the input frame starting from 0
+
+@item pts
+presentation timestamp of the input frame expressed in time base units
+
+@item r
+frame rate of the input video, NAN if the input frame rate is unknown
+
+@item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+@item tb
+time base of the input video
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Set the hue to 90 degrees and the saturation to 1.0:
+@example
+hue=h=90:s=1
+@end example
+
+@item
+Same command but expressing the hue in radians:
+@example
+hue=H=PI/2:s=1
+@end example
+
+@item
+Rotate hue and make the saturation swing between 0
+and 2 over a period of 1 second:
+@example
+hue="H=2*PI*t: s=sin(2*PI*t)+1"
+@end example
+
+@item
+Apply a 3 seconds saturation fade-in effect starting at 0:
+@example
+hue="s=min(t/3\,1)"
+@end example
+
+The general fade-in expression can be written as:
+@example
+hue="s=min(0\, max((t-START)/DURATION\, 1))"
+@end example
+
+@item
+Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
+@example
+hue="s=max(0\, min(1\, (8-t)/3))"
+@end example
+
+The general fade-out expression can be written as:
+@example
+hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
+@end example
+
+@end itemize
+
+@subsection Commands
+
+This filter supports the following commands:
+@table @option
+@item b
+@item s
+@item h
+@item H
+Modify the hue and/or the saturation and/or brightness of the input video.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+@end table
+
+@section 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:
+
+@table @option
+@item intl_thres
+Set interlacing threshold.
+@item prog_thres
+Set progressive threshold.
+@end table
+
+@section 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:
+
+@table @option
+@item luma_mode, l
+@item chroma_mode, c
+@item alpha_mode, a
+Available values for @var{luma_mode}, @var{chroma_mode} and
+@var{alpha_mode} are:
+
+@table @samp
+@item none
+Do nothing.
+
+@item deinterleave, d
+Deinterleave fields, placing one above the other.
+
+@item interleave, i
+Interleave fields. Reverse the effect of deinterleaving.
+@end table
+Default value is @code{none}.
+
+@item luma_swap, ls
+@item chroma_swap, cs
+@item alpha_swap, as
+Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
+@end table
+
+@section 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. A vertical lowpass filter
+is always applied in order to avoid twitter effects and reduce moiré patterns.
+
+@example
+ 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
+@end example
+
+It accepts the following optional parameters:
+
+@table @option
+@item scan
+determines whether the interlaced frame is taken from the even (tff - default)
+or odd (bff) lines of the progressive frame.
+@end table
+
+@section 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.
+
+@table @option
+@item 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.
+
+@item map
+Paint pixels exceeding the threshold value to white if set to 1.
+Default is 0.
+
+@item order
+Set the fields order. Swap fields if set to 1, leave fields alone if
+0. Default is 0.
+
+@item sharp
+Enable additional sharpening if set to 1. Default is 0.
+
+@item twoway
+Enable twoway sharpening if set to 1. Default is 0.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Apply default values:
+@example
+kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
+@end example
+
+@item
+Enable additional sharpening:
+@example
+kerndeint=sharp=1
+@end example
+
+@item
+Paint processed pixels in white:
+@example
+kerndeint=map=1
+@end example
+@end itemize
+
+@anchor{lut3d}
+@section lut3d
+
+Apply a 3D LUT to an input video.
+
+The filter accepts the following options:
+
+@table @option
+@item file
+Set the 3D LUT file name.
+
+Currently supported formats:
+@table @samp
+@item 3dl
+AfterEffects
+@item cube
+Iridas
+@item dat
+DaVinci
+@item m3d
+Pandora
+@end table
+@item interp
+Select interpolation mode.
+
+Available values are:
+
+@table @samp
+@item nearest
+Use values from the nearest defined point.
+@item trilinear
+Interpolate values using the 8 points defining a cube.
+@item tetrahedral
+Interpolate values using a tetrahedron.
+@end table
+@end table
+
+@section 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.
+
+@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
+to an RGB input video.
+
+These filters accept the following options:
+@table @option
+@item c0
+set first pixel component expression
+@item c1
+set second pixel component expression
+@item c2
+set third pixel component expression
+@item c3
+set fourth pixel component expression, corresponds to the alpha component
+
+@item r
+set red component expression
+@item g
+set green component expression
+@item b
+set blue component expression
+@item a
+alpha component expression
+
+@item y
+set Y/luminance component expression
+@item u
+set U/Cb component expression
+@item v
+set V/Cr component expression
+@end table
+
+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 @var{c*} options depends on the
+format in input.
+
+The @var{lut} filter requires either YUV or RGB pixel formats in input,
+@var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
+
+The expressions can contain the following constants and functions:
+
+@table @option
+@item w
+@item h
+the input width and height
+
+@item val
+input value for the pixel component
+
+@item clipval
+the input value clipped in the @var{minval}-@var{maxval} range
+
+@item maxval
+maximum value for the pixel component
+
+@item minval
+minimum value for the pixel component
+
+@item negval
+the negated value for the pixel component value clipped in the
+@var{minval}-@var{maxval} range , it corresponds to the expression
+"maxval-clipval+minval"
+
+@item clip(val)
+the computed value in @var{val} clipped in the
+@var{minval}-@var{maxval} range
+
+@item gammaval(gamma)
+the computed gamma correction value of the pixel component value
+clipped in the @var{minval}-@var{maxval} range, corresponds to the
+expression
+"pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
+
+@end table
+
+All expressions default to "val".
+
+@subsection Examples
+
+@itemize
+@item
+Negate input video:
+@example
+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"
+@end example
+
+The above is the same as:
+@example
+lutrgb="r=negval:g=negval:b=negval"
+lutyuv="y=negval:u=negval:v=negval"
+@end example
+
+@item
+Negate luminance:
+@example
+lutyuv=y=negval
+@end example
+
+@item
+Remove chroma components, turns the video into a graytone image:
+@example
+lutyuv="u=128:v=128"
+@end example
+
+@item
+Apply a luma burning effect:
+@example
+lutyuv="y=2*val"
+@end example
+
+@item
+Remove green and blue components:
+@example
+lutrgb="g=0:b=0"
+@end example
+
+@item
+Set a constant alpha channel value on input:
+@example
format=rgba,lutrgb=a="maxval-minval/2"
+@end example
+
+@item
+Correct luminance gamma by a 0.5 factor:
+@example
+lutyuv=y=gammaval(0.5)
+@end example
+
+@item
+Discard least significant bits of luma:
+@example
+lutyuv=y='bitand(val, 128+64+32)'
+@end example
+@end itemize
+
+@section mergeplanes
+
+Merge color channel components from several video streams.
+
+The filter accepts up to 4 input streams, and merge selected input
+planes to the output video.
+
+This filter accepts the following options:
+@table @option
+@item mapping
+Set input to output plane mapping. Default is @code{0}.
+
+The mappings is specified as a bitmap. It should be specified as a
+hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
+mapping for the first plane of the output stream. 'A' sets the number of
+the input stream to use (from 0 to 3), and 'a' the plane number of the
+corresponding input to use (from 0 to 3). The rest of the mappings is
+similar, 'Bb' describes the mapping for the output stream second
+plane, 'Cc' describes the mapping for the output stream third plane and
+'Dd' describes the mapping for the output stream fourth plane.
+
+@item format
+Set output pixel format. Default is @code{yuva444p}.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Merge three gray video streams of same width and height into single video stream:
+@example
+[a0][a1][a2]mergeplanes=0x001020:yuv444p
+@end example
+
+@item
+Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
+@example
+[a0][a1]mergeplanes=0x00010210:yuva444p
+@end example
+
+@item
+Swap Y and A plane in yuva444p stream:
+@example
+format=yuva444p,mergeplanes=0x03010200:yuva444p
+@end example
+
+@item
+Swap U and V plane in yuv420p stream:
+@example
+format=yuv420p,mergeplanes=0x000201:yuv420p
+@end example
+
+@item
+Cast a rgb24 clip to yuv444p:
+@example
+format=rgb24,mergeplanes=0x000102:yuv444p
+@end example
+@end itemize
+
+@section 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:
+@table @option
+@item mode
+Set the deinterlacing mode.
+
+It accepts one of the following values:
+@table @samp
+@item fast
+@item medium
+@item slow
+use iterative motion estimation
+@item extra_slow
+like @samp{slow}, but use multiple reference frames.
+@end table
+Default value is @samp{fast}.
+
+@item parity
+Set the picture field parity assumed for the input video. It must be
+one of the following values:
+
+@table @samp
+@item 0, tff
+assume top field first
+@item 1, bff
+assume bottom field first
+@end table
+
+Default value is @samp{bff}.
+
+@item 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.
+@end table
+
+@section mp
+
+Apply an MPlayer filter to the input video.
+
+This filter provides a wrapper around some 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 filter accepts the parameters:
+@var{filter_name}[:=]@var{filter_params}
+
+@var{filter_name} is the name of a supported MPlayer filter,
+@var{filter_params} is a string containing the parameters accepted by
+the named filter.
+
+The list of the currently supported filters follows:
+@table @var
+@item eq2
+@item eq
+@item fspp
+@item ilpack
+@item pp7
+@item softpulldown
+@item uspp
+@end table
+
+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.
+
+@subsection Examples
+
+@itemize
+@item
+Adjust gamma, brightness, contrast:
+@example
+mp=eq2=1.0:2:0.5
+@end example
+@end itemize
+
+See also mplayer(1), @url{http://www.mplayerhq.hu/}.
+
+@section 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.
+
+@table @option
+@item 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.
+
+@item hi
+@item lo
+@item frac
+Set the dropping threshold values.
+
+Values for @option{hi} and @option{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 @option{hi}, and if no more than @option{frac} blocks (1
+meaning the whole image) differ by more than a threshold of @option{lo}.
+
+Default value for @option{hi} is 64*12, default value for @option{lo} is
+64*5, and default value for @option{frac} is 0.33.
+@end table
+
+
+@section 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.
+
+@section 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:
+@table @option
+
+@item pix_fmts
+A '|'-separated list of pixel format names, for example
+"pix_fmts=yuv420p|monow|rgb24".
+
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Force libavfilter to use a format different from @var{yuv420p} for the
+input to the vflip filter:
+@example
+noformat=pix_fmts=yuv420p,vflip
+@end example
+
+@item
+Convert the input video to any of the formats not contained in the list:
+@example
+noformat=yuv420p|yuv444p|yuv410p
+@end example
+@end itemize
+
+@section noise
+
+Add noise on video input frame.
+
+The filter accepts the following options:
+
+@table @option
+@item all_seed
+@item c0_seed
+@item c1_seed
+@item c2_seed
+@item c3_seed
+Set noise seed for specific pixel component or all pixel components in case
+of @var{all_seed}. Default value is @code{123457}.
+
+@item all_strength, alls
+@item c0_strength, c0s
+@item c1_strength, c1s
+@item c2_strength, c2s
+@item c3_strength, c3s
+Set noise strength for specific pixel component or all pixel components in case
+@var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
+
+@item all_flags, allf
+@item c0_flags, c0f
+@item c1_flags, c1f
+@item c2_flags, c2f
+@item c3_flags, c3f
+Set pixel component flags or set flags for all components if @var{all_flags}.
+Available values for component flags are:
+@table @samp
+@item a
+averaged temporal noise (smoother)
+@item p
+mix random noise with a (semi)regular pattern
+@item t
+temporal noise (noise pattern changes between frames)
+@item u
+uniform noise (gaussian otherwise)
+@end table
+@end table
+
+@subsection Examples
+
+Add temporal and uniform noise to input video:
+@example
+noise=alls=20:allf=t+u
+@end example
+
+@section null
+
+Pass the video source unchanged to the output.
+
+@section ocv
+
+Apply video transform using libopencv.
+
+To enable this filter install libopencv library and headers and
+configure FFmpeg with @code{--enable-libopencv}.
+
+This filter accepts the following parameters:
+
+@table @option
+
+@item filter_name
+The name of the libopencv filter to apply.
+
+@item filter_params
+The parameters to pass to the libopencv filter. If not specified the default
+values are assumed.
+
+@end table
+
+Refer to the official libopencv documentation for more precise
+information:
+@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
+
+Follows the list of supported libopencv filters.
+
+@anchor{dilate}
+@subsection dilate
+
+Dilate an image by using a specific structuring element.
+This filter corresponds to the libopencv function @code{cvDilate}.
+
+It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
+
+@var{struct_el} represents a structuring element, and has the syntax:
+@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
+
+@var{cols} and @var{rows} represent the number of columns and rows of
+the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
+point, and @var{shape} the shape for the structuring element, and
+can be one of the values "rect", "cross", "ellipse", "custom".
+
+If the value for @var{shape} is "custom", it must be followed by a
+string of the form "=@var{filename}". The file with name
+@var{filename} is assumed to represent a binary image, with each
+printable character corresponding to a bright pixel. When a custom
+@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
+or columns and rows of the read file are assumed instead.
+
+The default value for @var{struct_el} is "3x3+0x0/rect".
+
+@var{nb_iterations} specifies the number of times the transform is
+applied to the image, and defaults to 1.
+
+Follow some example:
+@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
+@end example
+
+@subsection erode
+
+Erode an image by using a specific structuring element.
+This filter corresponds to the libopencv function @code{cvErode}.
+
+The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
+with the same syntax and semantics as the @ref{dilate} filter.
+
+@subsection smooth
+
+Smooth the input video.
+
+The filter takes the following parameters:
+@var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
+
+@var{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".
+
+@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
+parameters whose meanings depend on smooth type. @var{param1} and
+@var{param2} accept integer positive values or 0, @var{param3} and
+@var{param4} accept float values.
+
+The default value for @var{param1} is 3, the default value for the
+other parameters is 0.
+
+These parameters correspond to the parameters assigned to the
+libopencv function @code{cvSmooth}.
+
+@anchor{overlay}
+@section 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.
+
+@table @option
+@item x
+@item 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).
+
+@item eof_action
+The action to take when EOF is encountered on the secondary input, accepts one
+of the following values:
+
+@table @option
+@item repeat
+repeat the last frame (the default)
+@item endall
+end both streams
+@item pass
+pass through the main input
+@end table
+
+@item eval
+Set when the expressions for @option{x}, and @option{y} are evaluated.
+
+It accepts the following values:
+@table @samp
+@item init
+only evaluate expressions once during the filter initialization or
+when a command is processed
+
+@item frame
+evaluate expressions for each incoming frame
+@end table
+
+Default value is @samp{frame}.
+
+@item shortest
+If set to 1, force the output to terminate when the shortest input
+terminates. Default value is 0.
+
+@item format
+Set the format for the output video.
+
+It accepts the following values:
+@table @samp
+@item yuv420
+force YUV420 output
+
+@item yuv422
+force YUV422 output
+
+@item yuv444
+force YUV444 output
+
+@item rgb
+force RGB output
+@end table
+
+Default value is @samp{yuv420}.
+
+@item rgb @emph{(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
+@option{format} instead.
+
+@item repeatlast
+If set to 1, force the filter to draw the last overlay frame over the
+main input until the end of the stream. A value of 0 disables this
+behavior. Default value is 1.
+@end table
+
+The @option{x}, and @option{y} expressions can contain the following
+parameters.
+
+@table @option
+@item main_w, W
+@item main_h, H
+main input width and height
+
+@item overlay_w, w
+@item overlay_h, h
+overlay input width and height
+
+@item x
+@item y
+the computed values for @var{x} and @var{y}. They are evaluated for
+each new frame.
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values of the output
+format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
+@var{vsub} is 1.
+
+@item n
+the number of input frame, starting from 0
+
+@item pos
+the position in the file of the input frame, NAN if unknown
+
+@item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+@end table
+
+Note that the @var{n}, @var{pos}, @var{t} variables are available only
+when evaluation is done @emph{per frame}, and will evaluate to NAN
+when @option{eval} is set to @samp{init}.
+
+Be aware that frames are taken from each input video in timestamp
+order, hence, if their initial timestamps differ, it is a good idea
+to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
+have them begin in the same zero timestamp, as it does the example for
+the @var{movie} filter.
+
+You can chain together more overlays but you should test the
+efficiency of such approach.
+
+@subsection Commands
+
+This filter supports the following commands:
+@table @option
+@item x
+@item 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.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Draw the overlay at 10 pixels from the bottom right corner of the main
+video:
+@example
+overlay=main_w-overlay_w-10:main_h-overlay_h-10
+@end example
+
+Using named options the example above becomes:
+@example
+overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
+@end example
+
+@item
+Insert a transparent PNG logo in the bottom left corner of the input,
+using the @command{ffmpeg} tool with the @code{-filter_complex} option:
+@example
+ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
+@end example
+
+@item
+Insert 2 different transparent PNG logos (second logo on bottom
+right corner) using the @command{ffmpeg} tool:
+@example
+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
+@end example
+
+@item
+Add a transparent color layer on top of the main video, @code{WxH}
+must specify the size of the main input to the overlay filter:
+@example
+color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
+@end example
+
+@item
+Play an original video and a filtered version (here with the deshake
+filter) side by side using the @command{ffplay} tool:
+@example
+ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
+@end example
+
+The above command is the same as:
+@example
+ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
+@end example
+
+@item
+Make a sliding overlay appearing from the left to the right top part of the
+screen starting since time 2:
+@example
+overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
+@end example
+
+@item
+Compose output by putting two input videos side to side:
+@example
+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]
+"
+@end example
+
+@item
+mask 10-20 seconds of a video by applying the delogo filter to a section
+@example
+ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
+-vf '[in]split[split_main][split_delogo];[split_delogo]trim=start=360:end=371,delogo=0:0:640:480[delogoed];[split_main][delogoed]overlay=eof_action=pass[out]'
+masked.avi
+@end example
+
+@item
+Chain several overlays in cascade:
+@example
+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]
+@end example
+
+@end itemize
+
+@section owdenoise
+
+Apply Overcomplete Wavelet denoiser.
+
+The filter accepts the following options:
+
+@table @option
+@item 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 @code{8}.
+
+@item luma_strength, ls
+Set luma strength.
+
+Must be a double value in the range 0-1000, default is @code{1.0}.
+
+@item chroma_strength, cs
+Set chroma strength.
+
+Must be a double value in the range 0-1000, default is @code{1.0}.
+@end table
+
+@section pad
+
+Add paddings to the input image, and place the original input at the
+given coordinates @var{x}, @var{y}.
+
+This filter accepts the following parameters:
+
+@table @option
+@item width, w
+@item height, h
+Specify an expression for the size of the output image with the
+paddings added. If the value for @var{width} or @var{height} is 0, the
+corresponding input size is used for the output.
+
+The @var{width} expression can reference the value set by the
+@var{height} expression, and vice versa.
+
+The default value of @var{width} and @var{height} is 0.
+
+@item x
+@item 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 @var{x} expression can reference the value set by the @var{y}
+expression, and vice versa.
+
+The default value of @var{x} and @var{y} is 0.
+
+@item color
+Specify the color of the padded area. For the syntax of this option,
+check the "Color" section in the ffmpeg-utils manual.
+
+The default value of @var{color} is "black".
+@end table
+
+The value for the @var{width}, @var{height}, @var{x}, and @var{y}
+options are expressions containing the following constants:
+
+@table @option
+@item in_w
+@item in_h
+the input video width and height
+
+@item iw
+@item ih
+same as @var{in_w} and @var{in_h}
+
+@item out_w
+@item out_h
+the output width and height, that is the size of the padded area as
+specified by the @var{width} and @var{height} expressions
+
+@item ow
+@item oh
+same as @var{out_w} and @var{out_h}
+
+@item x
+@item y
+x and y offsets as specified by the @var{x} and @var{y}
+expressions, or NAN if not yet specified
+
+@item a
+same as @var{iw} / @var{ih}
+
+@item sar
+input sample aspect ratio
+
+@item dar
+input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+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:
+@example
+pad=640:480:0:40:violet
+@end example
+
+The example above is equivalent to the following command:
+@example
+pad=width=640:height=480:x=0:y=40:color=violet
+@end example
+
+@item
+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:
+@example
+pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
+@end example
+
+@item
+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:
+@example
+pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
+@end example
+
+@item
+Pad the input to get a final w/h ratio of 16:9:
+@example
+pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
+@end example
+
+@item
+In case of anamorphic video, in order to set the output display aspect
+correctly, it is necessary to use @var{sar} in the expression,
+according to the relation:
+@example
+(ih * X / ih) * sar = output_dar
+X = output_dar / sar
+@end example
+
+Thus the previous example needs to be modified to:
+@example
+pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
+@end example
+
+@item
+Double output size and put the input video in the bottom-right
+corner of the output padded area:
+@example
+pad="2*iw:2*ih:ow-iw:oh-ih"
+@end example
+@end itemize
+
+@section perspective
+
+Correct perspective of video not recorded perpendicular to the screen.
+
+A description of the accepted parameters follows.
+
+@table @option
+@item x0
+@item y0
+@item x1
+@item y1
+@item x2
+@item y2
+@item x3
+@item y3
+Set coordinates expression for top left, top right, bottom left and bottom right corners.
+Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
+
+The expressions can use the following variables:
+
+@table @option
+@item W
+@item H
+the width and height of video frame.
+@end table
+
+@item interpolation
+Set interpolation for perspective correction.
+
+It accepts the following values:
+@table @samp
+@item linear
+@item cubic
+@end table
+
+Default value is @samp{linear}.
+@end table
+
+@section phase
+
+Delay interlaced video by one field time so that the field order changes.
+
+The intended use is to fix PAL movies that have been captured with the
+opposite field order to the film-to-video transfer.
+
+A description of the accepted parameters follows.
+
+@table @option
+@item mode
+Set phase mode.
+
+It accepts the following values:
+@table @samp
+@item t
+Capture field order top-first, transfer bottom-first.
+Filter will delay the bottom field.
+
+@item b
+Capture field order bottom-first, transfer top-first.
+Filter will delay the top field.
+
+@item p
+Capture and transfer with the same field order. This mode only exists
+for the documentation of the other options to refer to, but if you
+actually select it, the filter will faithfully do nothing.
+
+@item a
+Capture field order determined automatically by field flags, transfer
+opposite.
+Filter selects among @samp{t} and @samp{b} modes on a frame by frame
+basis using field flags. If no field information is available,
+then this works just like @samp{u}.
+
+@item u
+Capture unknown or varying, transfer opposite.
+Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
+analyzing the images and selecting the alternative that produces best
+match between the fields.
+
+@item T
+Capture top-first, transfer unknown or varying.
+Filter selects among @samp{t} and @samp{p} using image analysis.
+
+@item B
+Capture bottom-first, transfer unknown or varying.
+Filter selects among @samp{b} and @samp{p} using image analysis.
+
+@item A
+Capture determined by field flags, transfer unknown or varying.
+Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
+image analysis. If no field information is available, then this works just
+like @samp{U}. This is the default mode.
+
+@item U
+Both capture and transfer unknown or varying.
+Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
+@end table
+@end table
+
+@section pixdesctest
+
+Pixel format descriptor test filter, mainly useful for internal
+testing. The output video should be equal to the input video.
+
+For example:
+@example
+format=monow, pixdesctest
+@end example
+
+can be used to test the monowhite pixel format descriptor definition.
+
+@section pp
+
+Enable the specified chain of postprocessing subfilters using libpostproc. This
+library should be automatically selected with a GPL build (@code{--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:
+
+@table @option
+@item subfilters
+Set postprocessing subfilters string.
+@end table
+
+All subfilters share common options to determine their scope:
+
+@table @option
+@item a/autoq
+Honor the quality commands for this subfilter.
+
+@item c/chrom
+Do chrominance filtering, too (default).
+
+@item y/nochrom
+Do luminance filtering only (no chrominance).
+
+@item n/noluma
+Do chrominance filtering only (no luminance).
+@end table
+
+These options can be appended after the subfilter name, separated by a '|'.
+
+Available subfilters are:
+
+@table @option
+@item hb/hdeblock[|difference[|flatness]]
+Horizontal deblocking filter
+@table @option
+@item difference
+Difference factor where higher values mean more deblocking (default: @code{32}).
+@item flatness
+Flatness threshold where lower values mean more deblocking (default: @code{39}).
+@end table
+
+@item vb/vdeblock[|difference[|flatness]]
+Vertical deblocking filter
+@table @option
+@item difference
+Difference factor where higher values mean more deblocking (default: @code{32}).
+@item flatness
+Flatness threshold where lower values mean more deblocking (default: @code{39}).
+@end table
+
+@item ha/hadeblock[|difference[|flatness]]
+Accurate horizontal deblocking filter
+@table @option
+@item difference
+Difference factor where higher values mean more deblocking (default: @code{32}).
+@item flatness
+Flatness threshold where lower values mean more deblocking (default: @code{39}).
+@end table
+
+@item va/vadeblock[|difference[|flatness]]
+Accurate vertical deblocking filter
+@table @option
+@item difference
+Difference factor where higher values mean more deblocking (default: @code{32}).
+@item flatness
+Flatness threshold where lower values mean more deblocking (default: @code{39}).
+@end table
+@end table
+
+The horizontal and vertical deblocking filters share the difference and
+flatness values so you cannot set different horizontal and vertical
+thresholds.
+
+@table @option
+@item h1/x1hdeblock
+Experimental horizontal deblocking filter
+
+@item v1/x1vdeblock
+Experimental vertical deblocking filter
+
+@item dr/dering
+Deringing filter
+
+@item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
+@table @option
+@item threshold1
+larger -> stronger filtering
+@item threshold2
+larger -> stronger filtering
+@item threshold3
+larger -> stronger filtering
+@end table
+
+@item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
+@table @option
+@item f/fullyrange
+Stretch luminance to @code{0-255}.
+@end table
+
+@item lb/linblenddeint
+Linear blend deinterlacing filter that deinterlaces the given block by
+filtering all lines with a @code{(1 2 1)} filter.
+
+@item li/linipoldeint
+Linear interpolating deinterlacing filter that deinterlaces the given block by
+linearly interpolating every second line.
+
+@item ci/cubicipoldeint
+Cubic interpolating deinterlacing filter deinterlaces the given block by
+cubically interpolating every second line.
+
+@item md/mediandeint
+Median deinterlacing filter that deinterlaces the given block by applying a
+median filter to every second line.
+
+@item fd/ffmpegdeint
+FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
+second line with a @code{(-1 4 2 4 -1)} filter.
+
+@item l5/lowpass5
+Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
+block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
+
+@item fq/forceQuant[|quantizer]
+Overrides the quantizer table from the input with the constant quantizer you
+specify.
+@table @option
+@item quantizer
+Quantizer to use
+@end table
+
+@item de/default
+Default pp filter combination (@code{hb|a,vb|a,dr|a})
+
+@item fa/fast
+Fast pp filter combination (@code{h1|a,v1|a,dr|a})
+
+@item ac
+High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Apply horizontal and vertical deblocking, deringing and automatic
+brightness/contrast:
+@example
+pp=hb/vb/dr/al
+@end example
+
+@item
+Apply default filters without brightness/contrast correction:
+@example
+pp=de/-al
+@end example
+
+@item
+Apply default filters and temporal denoiser:
+@example
+pp=default/tmpnoise|1|2|3
+@end example
+
+@item
+Apply deblocking on luminance only, and switch vertical deblocking on or off
+automatically depending on available CPU time:
+@example
+pp=hb|y/vb|a
+@end example
+@end itemize
+
+@section psnr
+
+Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
+Ratio) between two input videos.
+
+This filter takes in input two input videos, the first input is
+considered the "main" source and is passed unchanged to the
+output. The second input is used as a "reference" video for computing
+the PSNR.
+
+Both video inputs must have the same resolution and pixel format for
+this filter to work correctly. Also it assumes that both inputs
+have the same number of frames, which are compared one by one.
+
+The obtained average PSNR is printed through the logging system.
+
+The filter stores the accumulated MSE (mean squared error) of each
+frame, and at the end of the processing it is averaged across all frames
+equally, and the following formula is applied to obtain the PSNR:
+
+@example
+PSNR = 10*log10(MAX^2/MSE)
+@end example
+
+Where MAX is the average of the maximum values of each component of the
+image.
+
+The description of the accepted parameters follows.
+
+@table @option
+@item stats_file, f
+If specified the filter will use the named file to save the PSNR of
+each individual frame.
+@end table
+
+The file printed if @var{stats_file} is selected, contains a sequence of
+key/value pairs of the form @var{key}:@var{value} for each compared
+couple of frames.
+
+A description of each shown parameter follows:
+
+@table @option
+@item n
+sequential number of the input frame, starting from 1
+
+@item mse_avg
+Mean Square Error pixel-by-pixel average difference of the compared
+frames, averaged over all the image components.
+
+@item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
+Mean Square Error pixel-by-pixel average difference of the compared
+frames for the component specified by the suffix.
+
+@item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
+Peak Signal to Noise ratio of the compared frames for the component
+specified by the suffix.
+@end table
+
+For example:
+@example
+movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
+[main][ref] psnr="stats_file=stats.log" [out]
+@end example
+
+On this example the input file being processed is compared with the
+reference file @file{ref_movie.mpg}. The PSNR of each individual frame
+is stored in @file{stats.log}.
+
+@anchor{pullup}
+@section pullup
+
+Pulldown reversal (inverse telecine) filter, capable of handling mixed
+hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
+content.
+
+The pullup filter is designed to take advantage of future context in making
+its decisions. This filter is stateless in the sense that it does not lock
+onto a pattern to follow, but it instead looks forward to the following
+fields in order to identify matches and rebuild progressive frames.
+
+To produce content with an even framerate, insert the fps filter after
+pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
+@code{fps=24} for 30fps and the (rare) telecined 25fps input.
+
+The filter accepts the following options:
+
+@table @option
+@item jl
+@item jr
+@item jt
+@item jb
+These options set the amount of "junk" to ignore at the left, right, top, and
+bottom of the image, respectively. Left and right are in units of 8 pixels,
+while top and bottom are in units of 2 lines.
+The default is 8 pixels on each side.
+
+@item sb
+Set the strict breaks. Setting this option to 1 will reduce the chances of
+filter generating an occasional mismatched frame, but it may also cause an
+excessive number of frames to be dropped during high motion sequences.
+Conversely, setting it to -1 will make filter match fields more easily.
+This may help processing of video where there is slight blurring between
+the fields, but may also cause there to be interlaced frames in the output.
+Default value is @code{0}.
+
+@item mp
+Set the metric plane to use. It accepts the following values:
+@table @samp
+@item l
+Use luma plane.
+
+@item u
+Use chroma blue plane.
+
+@item v
+Use chroma red plane.
+@end table
+
+This option may be set to use chroma plane instead of the default luma plane
+for doing filter's computations. This may improve accuracy on very clean
+source material, but more likely will decrease accuracy, especially if there
+is chroma noise (rainbow effect) or any grayscale video.
+The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
+load and make pullup usable in realtime on slow machines.
+@end table
+
+For best results (without duplicated frames in the output file) it is
+necessary to change the output frame rate. For example, to inverse
+telecine NTSC input:
+@example
+ffmpeg -i input -vf pullup -r 24000/1001 ...
+@end example
+
+@section 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:
+
+@table @option
+@item 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.
+@end table
+
+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.
+
+@section rotate
+
+Rotate video by an arbitrary angle expressed in radians.
+
+The filter accepts the following options:
+
+A description of the optional parameters follows.
+@table @option
+@item 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.
+
+@item out_w, ow
+Set the output width expression, default value is "iw".
+This expression is evaluated just once during configuration.
+
+@item out_h, oh
+Set the output height expression, default value is "ih".
+This expression is evaluated just once during configuration.
+
+@item bilinear
+Enable bilinear interpolation if set to 1, a value of 0 disables
+it. Default value is 1.
+
+@item fillcolor, c
+Set the color used to fill the output area not covered by the rotated
+image. For the generalsyntax of this option, check the "Color" section in the
+ffmpeg-utils manual. If the special value "none" is selected then no
+background is printed (useful for example if the background is never shown).
+
+Default value is "black".
+@end table
+
+The expressions for the angle and the output size can contain the
+following constants and functions:
+
+@table @option
+@item n
+sequential number of the input frame, starting from 0. It is always NAN
+before the first frame is filtered.
+
+@item 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.
+
+@item hsub
+@item vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
+@item in_w, iw
+@item in_h, ih
+the input video width and height
+
+@item out_w, ow
+@item out_h, oh
+the output width and height, that is the size of the padded area as
+specified by the @var{width} and @var{height} expressions
+
+@item rotw(a)
+@item roth(a)
+the minimal width/height required for completely containing the input
+video rotated by @var{a} radians.
+
+These are only available when computing the @option{out_w} and
+@option{out_h} expressions.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Rotate the input by PI/6 radians clockwise:
+@example
+rotate=PI/6
+@end example
+
+@item
+Rotate the input by PI/6 radians counter-clockwise:
+@example
+rotate=-PI/6
+@end example
+
+@item
+Rotate the input by 45 degrees clockwise:
+@example
+rotate=45*PI/180
+@end example
+
+@item
+Apply a constant rotation with period T, starting from an angle of PI/3:
+@example
+rotate=PI/3+2*PI*t/T
+@end example
+
+@item
+Make the input video rotation oscillating with a period of T
+seconds and an amplitude of A radians:
+@example
+rotate=A*sin(2*PI/T*t)
+@end example
+
+@item
+Rotate the video, output size is choosen so that the whole rotating
+input video is always completely contained in the output:
+@example
+rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
+@end example
+
+@item
+Rotate the video, reduce the output size so that no background is ever
+shown:
+@example
+rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
+@end example
+@end itemize
+
+@subsection Commands
+
+The filter supports the following commands:
+
+@table @option
+@item 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.
+@end table
+
+@section sab
+
+Apply Shape Adaptive Blur.
+
+The filter accepts the following options:
+
+@table @option
+@item 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.
+
+@item 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.
+
+@item 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.
+
+@item 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.
+
+@item chroma_pre_filter_radius, cpfr
+Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
+
+@item chroma_strength, cs
+Set chroma maximum difference between pixels to still be considered,
+must be a value in the 0.1-100.0 range.
+@end table
+
+Each chroma option value, if not explicitly specified, is set to the
+corresponding luma option value.
+
+@anchor{scale}
+@section scale
+
+Scale (resize) the input video, using the libswscale library.
+
+The scale filter forces the output display aspect ratio to be the same
+of the input, by changing the output sample aspect ratio.
+
+If the input image format is different from the format requested by
+the next filter, the scale filter will convert the input to the
+requested format.
+
+@subsection Options
+The filter accepts the following options, or any of the options
+supported by the libswscale scaler.
+
+See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
+the complete list of scaler options.
+
+@table @option
+@item width, w
+@item height, h
+Set the output video dimension expression. Default value is the input
+dimension.
+
+If the value is 0, the input width is used for the output.
+
+If one of the values is -1, the scale filter will use a value that
+maintains the aspect ratio of the input image, calculated from the
+other specified dimension. If both of them are -1, the input size is
+used
+
+If one of the values is -n with n > 1, the scale filter will also use a value
+that maintains the aspect ratio of the input image, calculated from the other
+specified dimension. After that it will, however, make sure that the calculated
+dimension is divisible by n and adjust the value if necessary.
+
+See below for the list of accepted constants for use in the dimension
+expression.
+
+@item interl
+Set the interlacing mode. It accepts the following values:
+
+@table @samp
+@item 1
+Force interlaced aware scaling.
+
+@item 0
+Do not apply interlaced scaling.
+
+@item -1
+Select interlaced aware scaling depending on whether the source frames
+are flagged as interlaced or not.
+@end table
+
+Default value is @samp{0}.
+
+@item flags
+Set libswscale scaling flags. See
+@ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
+complete list of values. If not explictly specified the filter applies
+the default flags.
+
+@item size, s
+Set the video size. For the syntax of this option, check the "Video size"
+section in the ffmpeg-utils manual.
+
+@item in_color_matrix
+@item out_color_matrix
+Set in/output YCbCr color space type.
+
+This allows the autodetected value to be overridden as well as allows forcing
+a specific value used for the output and encoder.
+
+If not specified, the color space type depends on the pixel format.
+
+Possible values:
+
+@table @samp
+@item auto
+Choose automatically.
+
+@item bt709
+Format conforming to International Telecommunication Union (ITU)
+Recommendation BT.709.
+
+@item fcc
+Set color space conforming to the United States Federal Communications
+Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
+
+@item bt601
+Set color space conforming to:
+
+@itemize
+@item
+ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
+
+@item
+ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
+
+@item
+Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
+
+@end itemize
+
+@item smpte240m
+Set color space conforming to SMPTE ST 240:1999.
+@end table
+
+@item in_range
+@item out_range
+Set in/output YCbCr sample range.
+
+This allows the autodetected value to be overridden as well as allows forcing
+a specific value used for the output and encoder. If not specified, the
+range depends on the pixel format. Possible values:
+
+@table @samp
+@item auto
+Choose automatically.
+
+@item jpeg/full/pc
+Set full range (0-255 in case of 8-bit luma).
+
+@item mpeg/tv
+Set "MPEG" range (16-235 in case of 8-bit luma).
+@end table
+
+@item force_original_aspect_ratio
+Enable decreasing or increasing output video width or height if necessary to
+keep the original aspect ratio. Possible values:
+
+@table @samp
+@item disable
+Scale the video as specified and disable this feature.
+
+@item decrease
+The output video dimensions will automatically be decreased if needed.
+
+@item increase
+The output video dimensions will automatically be increased if needed.
+
+@end table
+
+One useful instance of this option is that when you know a specific device's
+maximum allowed resolution, you can use this to limit the output video to
+that, while retaining the aspect ratio. For example, device A allows
+1280x720 playback, and your video is 1920x800. Using this option (set it to
+decrease) and specifying 1280x720 to the command line makes the output
+1280x533.
+
+Please note that this is a different thing than specifying -1 for @option{w}
+or @option{h}, you still need to specify the output resolution for this option
+to work.
+
+@end table
+
+The values of the @option{w} and @option{h} options are expressions
+containing the following constants:
+
+@table @var
+@item in_w
+@item in_h
+the input width and height
+
+@item iw
+@item ih
+same as @var{in_w} and @var{in_h}
+
+@item out_w
+@item out_h
+the output (scaled) width and height
+
+@item ow
+@item oh
+same as @var{out_w} and @var{out_h}
+
+@item a
+same as @var{iw} / @var{ih}
+
+@item sar
+input sample aspect ratio
+
+@item dar
+input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
+
+@item hsub
+@item vsub
+horizontal and vertical input chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
+@item ohsub
+@item ovsub
+horizontal and vertical output chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Scale the input video to a size of 200x100:
+@example
+scale=w=200:h=100
+@end example
+
+This is equivalent to:
+@example
+scale=200:100
+@end example
+
+or:
+@example
+scale=200x100
+@end example
+
+@item
+Specify a size abbreviation for the output size:
+@example
+scale=qcif
+@end example
+
+which can also be written as:
+@example
+scale=size=qcif
+@end example
+
+@item
+Scale the input to 2x:
+@example
+scale=w=2*iw:h=2*ih
+@end example
+
+@item
+The above is the same as:
+@example
+scale=2*in_w:2*in_h
+@end example
+
+@item
+Scale the input to 2x with forced interlaced scaling:
+@example
+scale=2*iw:2*ih:interl=1
+@end example
+
+@item
+Scale the input to half size:
+@example
+scale=w=iw/2:h=ih/2
+@end example
+
+@item
+Increase the width, and set the height to the same size:
+@example
+scale=3/2*iw:ow
+@end example
+
+@item
+Seek for Greek harmony:
+@example
+scale=iw:1/PHI*iw
+scale=ih*PHI:ih
+@end example
+
+@item
+Increase the height, and set the width to 3/2 of the height:
+@example
+scale=w=3/2*oh:h=3/5*ih
+@end example
+
+@item
+Increase the size, but make the size a multiple of the chroma
+subsample values:
+@example
+scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
+@end example
+
+@item
+Increase the width to a maximum of 500 pixels, keep the same input
+aspect ratio:
+@example
+scale=w='min(500\, iw*3/2):h=-1'
+@end example
+@end itemize
+
+@section separatefields
+
+The @code{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 @ref{setfield} filter before @code{separatefields} filter.
+
+@section setdar, setsar
+
+The @code{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:
+@example
+@var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
+@end example
+
+Keep in mind that the @code{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 @code{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 @code{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:
+
+@table @option
+@item r, ratio, dar (@code{setdar} only), sar (@code{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 @var{num}:@var{den}, where @var{num} and
+@var{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 "@var{num}:@var{den}" is used, the @code{:} character
+should be escaped.
+
+@item 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 @code{100}.
+
+@end table
+
+The parameter @var{sar} is an expression containing
+the following constants:
+
+@table @option
+@item E, PI, PHI
+the corresponding mathematical approximated values for e
+(euler number), pi (greek PI), phi (golden ratio)
+
+@item w, h
+the input width and height
+
+@item a
+same as @var{w} / @var{h}
+
+@item sar
+input sample aspect ratio
+
+@item dar
+input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
+
+@item hsub, vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+@end table
+
+@subsection Examples
+
+@itemize
+
+@item
+To change the display aspect ratio to 16:9, specify one of the following:
+@example
+setdar=dar=1.77777
+setdar=dar=16/9
+setdar=dar=1.77777
+@end example
+
+@item
+To change the sample aspect ratio to 10:11, specify:
+@example
+setsar=sar=10/11
+@end example
+
+@item
+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:
+@example
+setdar=ratio=16/9:max=1000
+@end example
+
+@end itemize
+
+@anchor{setfield}
+@section setfield
+
+Force field for the output video frame.
+
+The @code{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. @code{fieldorder} or @code{yadif}).
+
+The filter accepts the following options:
+
+@table @option
+
+@item mode
+Available values are:
+
+@table @samp
+@item auto
+Keep the same field property.
+
+@item bff
+Mark the frame as bottom-field-first.
+
+@item tff
+Mark the frame as top-field-first.
+
+@item prog
+Mark the frame as progressive.
+@end table
+@end table
+
+@section 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
+@var{key}:@var{value}.
+
+A description of each shown parameter follows:
+
+@table @option
+@item n
+sequential number of the input frame, starting from 0
+
+@item 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.
+
+@item pts_time
+Presentation TimeStamp of the input frame, expressed as a number of
+seconds
+
+@item 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)
+
+@item fmt
+pixel format name
+
+@item sar
+sample aspect ratio of the input frame, expressed in the form
+@var{num}/@var{den}
+
+@item s
+size of the input frame. For the syntax of this option, check the "Video size"
+section in the ffmpeg-utils manual.
+
+@item i
+interlaced mode ("P" for "progressive", "T" for top field first, "B"
+for bottom field first)
+
+@item iskey
+1 if the frame is a key frame, 0 otherwise
+
+@item 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 @code{AVPictureType} enum and of
+the @code{av_get_picture_type_char} function defined in
+@file{libavutil/avutil.h}.
+
+@item checksum
+Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
+
+@item plane_checksum
+Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
+expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
+@end table
+
+@anchor{smartblur}
+@section smartblur
+
+Blur the input video without impacting the outlines.
+
+The filter accepts the following options:
+
+@table @option
+@item 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.
+
+@item 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.
+
+@item 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.
+
+@item 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.
+
+@item 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.
+
+@item 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.
+@end table
+
+If a chroma option is not explicitly set, the corresponding luma value
+is set.
+
+@section stereo3d
+
+Convert between different stereoscopic image formats.
+
+The filters accept the following options:
+
+@table @option
+@item in
+Set stereoscopic image format of input.
+
+Available values for input image formats are:
+@table @samp
+@item sbsl
+side by side parallel (left eye left, right eye right)
+
+@item sbsr
+side by side crosseye (right eye left, left eye right)
+
+@item sbs2l
+side by side parallel with half width resolution
+(left eye left, right eye right)
+
+@item sbs2r
+side by side crosseye with half width resolution
+(right eye left, left eye right)
+
+@item abl
+above-below (left eye above, right eye below)
+
+@item abr
+above-below (right eye above, left eye below)
+
+@item ab2l
+above-below with half height resolution
+(left eye above, right eye below)
+
+@item ab2r
+above-below with half height resolution
+(right eye above, left eye below)
+
+@item al
+alternating frames (left eye first, right eye second)
+
+@item ar
+alternating frames (right eye first, left eye second)
+
+Default value is @samp{sbsl}.
+@end table
+
+@item out
+Set stereoscopic image format of output.
+
+Available values for output image formats are all the input formats as well as:
+@table @samp
+@item arbg
+anaglyph red/blue gray
+(red filter on left eye, blue filter on right eye)
+
+@item argg
+anaglyph red/green gray
+(red filter on left eye, green filter on right eye)
+
+@item arcg
+anaglyph red/cyan gray
+(red filter on left eye, cyan filter on right eye)
+
+@item arch
+anaglyph red/cyan half colored
+(red filter on left eye, cyan filter on right eye)
+
+@item arcc
+anaglyph red/cyan color
+(red filter on left eye, cyan filter on right eye)
+
+@item arcd
+anaglyph red/cyan color optimized with the least squares projection of dubois
+(red filter on left eye, cyan filter on right eye)
+
+@item agmg
+anaglyph green/magenta gray
+(green filter on left eye, magenta filter on right eye)
+
+@item agmh
+anaglyph green/magenta half colored
+(green filter on left eye, magenta filter on right eye)
+
+@item agmc
+anaglyph green/magenta colored
+(green filter on left eye, magenta filter on right eye)
+
+@item agmd
+anaglyph green/magenta color optimized with the least squares projection of dubois
+(green filter on left eye, magenta filter on right eye)
+
+@item aybg
+anaglyph yellow/blue gray
+(yellow filter on left eye, blue filter on right eye)
+
+@item aybh
+anaglyph yellow/blue half colored
+(yellow filter on left eye, blue filter on right eye)
+
+@item aybc
+anaglyph yellow/blue colored
+(yellow filter on left eye, blue filter on right eye)
+
+@item aybd
+anaglyph yellow/blue color optimized with the least squares projection of dubois
+(yellow filter on left eye, blue filter on right eye)
+
+@item irl
+interleaved rows (left eye has top row, right eye starts on next row)
+
+@item irr
+interleaved rows (right eye has top row, left eye starts on next row)
+
+@item ml
+mono output (left eye only)
+
+@item mr
+mono output (right eye only)
+@end table
+
+Default value is @samp{arcd}.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Convert input video from side by side parallel to anaglyph yellow/blue dubois:
+@example
+stereo3d=sbsl:aybd
+@end example
+
+@item
+Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
+@example
+stereo3d=abl:sbsr
+@end example
+@end itemize
+
+@section spp
+
+Apply a simple postprocessing filter that compresses and decompresses the image
+at several (or - in the case of @option{quality} level @code{6} - all) shifts
+and average the results.
+
+The filter accepts the following options:
+
+@table @option
+@item quality
+Set quality. This option defines the number of levels for averaging. It accepts
+an integer in the range 0-6. If set to @code{0}, the filter will have no
+effect. A value of @code{6} means the higher quality. For each increment of
+that value the speed drops by a factor of approximately 2. Default value is
+@code{3}.
+
+@item qp
+Force a constant quantization parameter. If not set, the filter will use the QP
+from the video stream (if available).
+
+@item mode
+Set thresholding mode. Available modes are:
+
+@table @samp
+@item hard
+Set hard thresholding (default).
+@item soft
+Set soft thresholding (better de-ringing effect, but likely blurrier).
+@end table
+
+@item use_bframe_qp
+Enable the use of the QP from the B-Frames if set to @code{1}. Using this
+option may cause flicker since the B-Frames have often larger QP. Default is
+@code{0} (not enabled).
+@end table
+
+@anchor{subtitles}
+@section subtitles
+
+Draw subtitles on top of input video using the libass library.
+
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--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:
+
+@table @option
+@item filename, f
+Set the filename of the subtitle file to read. It must be specified.
+
+@item original_size
+Specify the size of the original video, the video for which the ASS file
+was composed. For the syntax of this option, check the "Video size" section in
+the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
+this is necessary to correctly scale the fonts if the aspect ratio has been
+changed.
+
+@item charenc
+Set subtitles input character encoding. @code{subtitles} filter only. Only
+useful if not UTF-8.
+@end table
+
+If the first key is not specified, it is assumed that the first value
+specifies the @option{filename}.
+
+For example, to render the file @file{sub.srt} on top of the input
+video, use the command:
+@example
+subtitles=sub.srt
+@end example
+
+which is equivalent to:
+@example
+subtitles=filename=sub.srt
+@end example
+
+@section 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.
+
+@section swapuv
+Swap U & V plane.
+
+@section telecine
+
+Apply telecine process to the video.
+
+This filter accepts the following options:
+
+@table @option
+@item first_field
+@table @samp
+@item top, t
+top field first
+@item bottom, b
+bottom field first
+The default value is @code{top}.
+@end table
+
+@item pattern
+A string of numbers representing the pulldown pattern you wish to apply.
+The default value is @code{23}.
+@end table
+
+@example
+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
+@end example
+
+@section thumbnail
+Select the most representative frame in a given sequence of consecutive frames.
+
+The filter accepts the following options:
+
+@table @option
+@item n
+Set the frames batch size to analyze; in a set of @var{n} frames, the filter
+will pick one of them, and then handle the next batch of @var{n} frames until
+the end. Default is @code{100}.
+@end table
+
+Since the filter keeps track of the whole frames sequence, a bigger @var{n}
+value will result in a higher memory usage, so a high value is not recommended.
+
+@subsection Examples
+
+@itemize
+@item
+Extract one picture each 50 frames:
+@example
+thumbnail=50
+@end example
+
+@item
+Complete example of a thumbnail creation with @command{ffmpeg}:
+@example
+ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
+@end example
+@end itemize
+
+@section tile
+
+Tile several successive frames together.
+
+The filter accepts the following options:
+
+@table @option
+
+@item layout
+Set the grid size (i.e. the number of lines and columns). For the syntax of
+this option, check the "Video size" section in the ffmpeg-utils manual.
+
+@item nb_frames
+Set the maximum number of frames to render in the given area. It must be less
+than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
+the area will be used.
+
+@item margin
+Set the outer border margin in pixels.
+
+@item 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.
+
+@item color
+Specify the color of the unused areaFor the syntax of this option, check the
+"Color" section in the ffmpeg-utils manual. The default value of @var{color}
+is "black".
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
+@example
+ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
+@end example
+The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
+duplicating each output frame to accomodate the originally detected frame
+rate.
+
+@item
+Display @code{5} pictures in an area of @code{3x2} frames,
+with @code{7} pixels between them, and @code{2} pixels of initial margin, using
+mixed flat and named options:
+@example
+tile=3x2:nb_frames=5:padding=7:margin=2
+@end example
+@end itemize
+
+@section 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:
+
+@table @option
+
+@item 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:
+
+@table @samp
+@item merge, 0
+Move odd frames into the upper field, even into the lower field,
+generating a double height frame at half frame rate.
+
+@item drop_odd, 1
+Only output even frames, odd frames are dropped, generating a frame with
+unchanged height at half frame rate.
+
+@item drop_even, 2
+Only output odd frames, even frames are dropped, generating a frame with
+unchanged height at half frame rate.
+
+@item 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.
+
+@item 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.
+
+@item 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.
+
+@item 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.
+@end table
+
+Numeric values are deprecated but are accepted for backward
+compatibility reasons.
+
+Default mode is @code{merge}.
+
+@item flags
+Specify flags influencing the filter process.
+
+Available value for @var{flags} is:
+
+@table @option
+@item 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 @option{mode}
+@var{interleave_top} and @var{interleave_bottom}.
+
+@end table
+@end table
+
+@section transpose
+
+Transpose rows with columns in the input video and optionally flip it.
+
+This filter accepts the following options:
+
+@table @option
+
+@item dir
+Specify the transposition direction.
+
+Can assume the following values:
+@table @samp
+@item 0, 4, cclock_flip
+Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
+@example
+L.R L.l
+. . -> . .
+l.r R.r
+@end example
+
+@item 1, 5, clock
+Rotate by 90 degrees clockwise, that is:
+@example
+L.R l.L
+. . -> . .
+l.r r.R
+@end example
+
+@item 2, 6, cclock
+Rotate by 90 degrees counterclockwise, that is:
+@example
+L.R R.r
+. . -> . .
+l.r L.l
+@end example
+
+@item 3, 7, clock_flip
+Rotate by 90 degrees clockwise and vertically flip, that is:
+@example
+L.R r.R
+. . -> . .
+l.r l.L
+@end example
+@end table
+
+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 @code{passthrough} option should be used instead.
+
+Numerical values are deprecated, and should be dropped in favor of
+symbolic constants.
+
+@item passthrough
+Do not apply the transposition if the input geometry matches the one
+specified by the specified value. It accepts the following values:
+@table @samp
+@item none
+Always apply transposition.
+@item portrait
+Preserve portrait geometry (when @var{height} >= @var{width}).
+@item landscape
+Preserve landscape geometry (when @var{width} >= @var{height}).
+@end table
+
+Default value is @code{none}.
+@end table
+
+For example to rotate by 90 degrees clockwise and preserve portrait
+layout:
+@example
+transpose=dir=1:passthrough=portrait
+@end example
+
+The command above can also be specified as:
+@example
+transpose=1:portrait
+@end example
+
+@section trim
+Trim the input so that the output contains one continuous subpart of the input.
+
+This filter accepts the following options:
+@table @option
+@item start
+Specify time of the start of the kept section, i.e. the frame with the
+timestamp @var{start} will be the first frame in the output.
+
+@item end
+Specify time of the first frame that will be dropped, i.e. the frame
+immediately preceding the one with the timestamp @var{end} will be the last
+frame in the output.
+
+@item start_pts
+Same as @var{start}, except this option sets the start timestamp in timebase
+units instead of seconds.
+
+@item end_pts
+Same as @var{end}, except this option sets the end timestamp in timebase units
+instead of seconds.
+
+@item duration
+Specify maximum duration of the output.
+
+@item start_frame
+Number of the first frame that should be passed to output.
+
+@item end_frame
+Number of the first frame that should be dropped.
+@end table
+
+@option{start}, @option{end}, @option{duration} are expressed as time
+duration specifications, check the "Time duration" section in the
+ffmpeg-utils manual.
+
+Note that the first two sets of the start/end options and the @option{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:
+@itemize
+@item
+drop everything except the second minute of input
+@example
+ffmpeg -i INPUT -vf trim=60:120
+@end example
+
+@item
+keep only the first second
+@example
+ffmpeg -i INPUT -vf trim=duration=1
+@end example
+
+@end itemize
+
+
+@section unsharp
+
+Sharpen or blur the input video.
+
+It accepts the following parameters:
+
+@table @option
+@item luma_msize_x, lx
+Set the luma matrix horizontal size. It must be an odd integer between
+3 and 63, default value is 5.
+
+@item luma_msize_y, ly
+Set the luma matrix vertical size. It must be an odd integer between 3
+and 63, default value is 5.
+
+@item 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.
+
+@item chroma_msize_x, cx
+Set the chroma matrix horizontal size. It must be an odd integer
+between 3 and 63, default value is 5.
+
+@item chroma_msize_y, cy
+Set the chroma matrix vertical size. It must be an odd integer
+between 3 and 63, default value is 5.
+
+@item 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.
+
+@item opencl
+If set to 1, specify using OpenCL capabilities, only available if
+FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
+
+@end table
+
+All parameters are optional and default to the equivalent of the
+string '5:5:1.0:5:5:0.0'.
+
+@subsection Examples
+
+@itemize
+@item
+Apply strong luma sharpen effect:
+@example
+unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
+@end example
+
+@item
+Apply strong blur of both luma and chroma parameters:
+@example
+unsharp=7:7:-2:7:7:-2
+@end example
+@end itemize
+
+@anchor{vidstabdetect}
+@section vidstabdetect
+
+Analyze video stabilization/deshaking. Perform pass 1 of 2, see
+@ref{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 @ref{vidstabtransform} filter.
+
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-libvidstab}.
+
+This filter accepts the following options:
+
+@table @option
+@item result
+Set the path to the file used to write the transforms information.
+Default value is @file{transforms.trf}.
+
+@item 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.
+
+@item accuracy
+Set the accuracy of the detection process. It must be a value in the
+range 1-15. A value of 1 means low accuracy, a value of 15 means high
+accuracy. Default value is 15.
+
+@item stepsize
+Set stepsize of the search process. The region around minimum is
+scanned with 1 pixel resolution. Default value is 6.
+
+@item 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.
+
+@item 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.
+
+@item 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.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Use default values:
+@example
+vidstabdetect
+@end example
+
+@item
+Analyze strongly shaky movie and put the results in file
+@file{mytransforms.trf}:
+@example
+vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
+@end example
+
+@item
+Visualize the result of internal transformations in the resulting
+video:
+@example
+vidstabdetect=show=1
+@end example
+
+@item
+Analyze a video with medium shakiness using @command{ffmpeg}:
+@example
+ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
+@end example
+@end itemize
+
+@anchor{vidstabtransform}
+@section vidstabtransform
+
+Video stabilization/deshaking: pass 2 of 2,
+see @ref{vidstabdetect} for pass 1.
+
+Read a file with transform information for each frame and
+apply/compensate them. Together with the @ref{vidstabdetect}
+filter this can be used to deshake videos. See also
+@url{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
+@code{--enable-libvidstab}.
+
+@subsection Options
+
+@table @option
+@item input
+Set path to the file used to read the transforms. Default value is
+@file{transforms.trf}).
+
+@item smoothing
+Set the number of frames (value*2 + 1) used for lowpass filtering the
+camera movements. Default value is 10.
+
+For example a number of 10 means that 21 frames are used (10 in the
+past and 10 in the future) to smoothen the motion in the video. A
+larger values leads to a smoother video, but limits the acceleration
+of the camera (pan/tilt movements). 0 is a special case where a
+static camera is simulated.
+
+@item optalgo
+Set the camera path optimization algorithm.
+
+Accepted values are:
+@table @samp
+@item gauss
+gaussian kernel low-pass filter on camera motion (default)
+@item avg
+averaging on transformations
+@end table
+
+@item maxshift
+Set maximal number of pixels to translate frames. Default value is -1,
+meaning no limit.
+
+@item maxangle
+Set maximal angle in radians (degree*PI/180) to rotate frames. Default
+value is -1, meaning no limit.
+
+@item crop
+Specify how to deal with borders that may be visible due to movement
+compensation.
+
+Available values are:
+@table @samp
+@item keep
+keep image information from previous frame (default)
+@item black
+fill the border black
+@end table
+
+@item invert
+Invert transforms if set to 1. Default value is 0.
+
+@item relative
+Consider transforms as relative to previsou frame if set to 1,
+absolute if set to 0. Default value is 0.
+
+@item zoom
+Set percentage to zoom. A positive value will result in a zoom-in
+effect, a negative value in a zoom-out effect. Default value is 0 (no
+zoom).
+
+@item optzoom
+Set optimal zooming to avoid borders.
+
+Accepted values are:
+@table @samp
+@item 0
+disabled
+@item 1
+optimal static zoom value is determined (only very strong movements
+will lead to visible borders) (default)
+@item 2
+optimal adaptive zoom value is determined (no borders will be
+visible), see @option{zoomspeed}
+@end table
+
+Note that the value given at zoom is added to the one calculated here.
+
+@item zoomspeed
+Set percent to zoom maximally each frame (enabled when
+@option{optzoom} is set to 2). Range is from 0 to 5, default value is
+0.25.
+
+@item interpol
+Specify type of interpolation.
+
+Available values are:
+@table @samp
+@item no
+no interpolation
+@item linear
+linear only horizontal
+@item bilinear
+linear in both directions (default)
+@item bicubic
+cubic in both directions (slow)
+@end table
+
+@item tripod
+Enable virtual tripod mode if set to 1, which is equivalent to
+@code{relative=0:smoothing=0}. Default value is 0.
+
+Use also @code{tripod} option of @ref{vidstabdetect}.
+
+@item debug
+Increase log verbosity if set to 1. Also the detected global motions
+are written to the temporary file @file{global_motions.trf}. Default
+value is 0.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Use @command{ffmpeg} for a typical stabilization with default values:
+@example
+ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
+@end example
+
+Note the use of the unsharp filter which is always recommended.
+
+@item
+Zoom in a bit more and load transform data from a given file:
+@example
+vidstabtransform=zoom=5:input="mytransforms.trf"
+@end example
+
+@item
+Smoothen the video even more:
+@example
+vidstabtransform=smoothing=30
+@end example
+@end itemize
+
+@section vflip
+
+Flip the input video vertically.
+
+For example, to vertically flip a video with @command{ffmpeg}:
+@example
+ffmpeg -i in.avi -vf "vflip" out.avi
+@end example
+
+@section vignette
+
+Make or reverse a natural vignetting effect.
+
+The filter accepts the following options:
+
+@table @option
+@item angle, a
+Set lens angle expression as a number of radians.
+
+The value is clipped in the @code{[0,PI/2]} range.
+
+Default value: @code{"PI/5"}
+
+@item x0
+@item y0
+Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
+by default.
+
+@item mode
+Set forward/backward mode.
+
+Available modes are:
+@table @samp
+@item forward
+The larger the distance from the central point, the darker the image becomes.
+
+@item 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 @option{angle} and other settings (yet). It can
+also be used to create a burning effect.
+@end table
+
+Default value is @samp{forward}.
+
+@item eval
+Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
+
+It accepts the following values:
+@table @samp
+@item init
+Evaluate expressions only once during the filter initialization.
+
+@item frame
+Evaluate expressions for each incoming frame. This is way slower than the
+@samp{init} mode since it requires all the scalers to be re-computed, but it
+allows advanced dynamic expressions.
+@end table
+
+Default value is @samp{init}.
+
+@item dither
+Set dithering to reduce the circular banding effects. Default is @code{1}
+(enabled).
+
+@item 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 @code{1/1}.
+@end table
+
+@subsection Expressions
+
+The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
+following parameters.
+
+@table @option
+@item w
+@item h
+input width and height
+
+@item n
+the number of input frame, starting from 0
+
+@item pts
+the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
+@var{TB} units, NAN if undefined
+
+@item r
+frame rate of the input video, NAN if the input frame rate is unknown
+
+@item t
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in seconds, NAN if undefined
+
+@item tb
+time base of the input video
+@end table
+
+
+@subsection Examples
+
+@itemize
+@item
+Apply simple strong vignetting effect:
+@example
+vignette=PI/4
+@end example
+
+@item
+Make a flickering vignetting:
+@example
+vignette='PI/4+random(1)*PI/50':eval=frame
+@end example
+
+@end itemize
+
+@section w3fdif
+
+Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
+Deinterlacing Filter").
+
+Based on the process described by Martin Weston for BBC R&D, and
+implemented based on the de-interlace algorithm written by Jim
+Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
+uses filter coefficients calculated by BBC R&D.
+
+There are two sets of filter coefficients, so called "simple":
+and "complex". Which set of filter coefficients is used can
+be set by passing an optional parameter:
+
+@table @option
+@item filter
+Set the interlacing filter coefficients. Accepts one of the following values:
+
+@table @samp
+@item simple
+Simple filter coefficient set.
+@item complex
+More-complex filter coefficient set.
+@end table
+Default value is @samp{complex}.
+
+@item deint
+Specify which frames to deinterlace. Accept one of the following values:
+
+@table @samp
+@item all
+Deinterlace all frames,
+@item interlaced
+Only deinterlace frames marked as interlaced.
+@end table
+
+Default value is @samp{all}.
+@end table
+
+@anchor{yadif}
+@section yadif
+
+Deinterlace the input video ("yadif" means "yet another deinterlacing
+filter").
+
+This filter accepts the following options:
+
+
+@table @option
+
+@item mode
+The interlacing mode to adopt, accepts one of the following values:
+
+@table @option
+@item 0, send_frame
+output 1 frame for each frame
+@item 1, send_field
+output 1 frame for each field
+@item 2, send_frame_nospatial
+like @code{send_frame} but skip spatial interlacing check
+@item 3, send_field_nospatial
+like @code{send_field} but skip spatial interlacing check
+@end table
+
+Default value is @code{send_frame}.
+
+@item parity
+The picture field parity assumed for the input interlaced video, accepts one of
+the following values:
+
+@table @option
+@item 0, tff
+assume top field first
+@item 1, bff
+assume bottom field first
+@item -1, auto
+enable automatic detection
+@end table
+
+Default value is @code{auto}.
+If interlacing is unknown or decoder does not export this information,
+top field first will be assumed.
+
+@item deint
+Specify which frames to deinterlace. Accept one of the following
+values:
+
+@table @option
+@item 0, all
+deinterlace all frames
+@item 1, interlaced
+only deinterlace frames marked as interlaced
+@end table
+
+Default value is @code{all}.
+@end table
+
+@c man end VIDEO FILTERS
+
+@chapter Video Sources
+@c man begin VIDEO SOURCES
+
+Below is a description of the currently available video sources.
+
+@section 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 @file{libavfilter/vsrc_buffer.h}.
+
+This source accepts the following options:
+
+@table @option
+
+@item video_size
+Specify the size (width and height) of the buffered video frames. For the
+syntax of this option, check the "Video size" section in the ffmpeg-utils
+manual.
+
+@item width
+Input video width.
+
+@item height
+Input video height.
+
+@item 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.
+
+@item time_base
+Specify the timebase assumed by the timestamps of the buffered frames.
+
+@item frame_rate
+Specify the frame rate expected for the video stream.
+
+@item pixel_aspect, sar
+Specify the sample aspect ratio assumed by the video frames.
+
+@item 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.
+@end table
+
+For example:
+@example
+buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
+@end example
+
+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 @file{libavutil/pixfmt.h}),
+this example corresponds to:
+@example
+buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
+@end example
+
+Alternatively, the options can be specified as a flat string, but this
+syntax is deprecated:
+
+@var{width}:@var{height}:@var{pix_fmt}:@var{time_base.num}:@var{time_base.den}:@var{pixel_aspect.num}:@var{pixel_aspect.den}[:@var{sws_param}]
+
+@section cellauto
+
+Create a pattern generated by an elementary cellular automaton.
+
+The initial state of the cellular automaton can be defined through the
+@option{filename}, and @option{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 @option{scroll} option.
+
+This source accepts the following options:
+
+@table @option
+@item 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.
+
+@item 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.
+
+@item rate, r
+Set the video rate, that is the number of frames generated per second.
+Default is 25.
+
+@item 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.
+
+@item 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.
+
+@item rule
+Set the cellular automaton rule, it is a number ranging from 0 to 255.
+Default value is 110.
+
+@item size, s
+Set the size of the output video. For the syntax of this option, check
+the "Video size" section in the ffmpeg-utils manual.
+
+If @option{filename} or @option{pattern} is specified, the size is set
+by default to the width of the specified initial state row, and the
+height is set to @var{width} * PHI.
+
+If @option{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).
+
+@item 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.
+
+@item 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.
+
+@item 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.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Read the initial state from @file{pattern}, and specify an output of
+size 200x400.
+@example
+cellauto=f=pattern:s=200x400
+@end example
+
+@item
+Generate a random initial row with a width of 200 cells, with a fill
+ratio of 2/3:
+@example
+cellauto=ratio=2/3:s=200x200
+@end example
+
+@item
+Create a pattern generated by rule 18 starting by a single alive cell
+centered on an initial row with width 100:
+@example
+cellauto=p=@@:s=100x400:full=0:rule=18
+@end example
+
+@item
+Specify a more elaborated initial pattern:
+@example
+cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
+@end example
+
+@end itemize
+
+@section mandelbrot
+
+Generate a Mandelbrot set fractal, and progressively zoom towards the
+point specified with @var{start_x} and @var{start_y}.
+
+This source accepts the following options:
+
+@table @option
+
+@item end_pts
+Set the terminal pts value. Default value is 400.
+
+@item end_scale
+Set the terminal scale value.
+Must be a floating point value. Default value is 0.3.
+
+@item 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:
+@table @option
+@item black
+Set black mode.
+@item convergence
+Show time until convergence.
+@item mincol
+Set color based on point closest to the origin of the iterations.
+@item period
+Set period mode.
+@end table
+
+Default value is @var{mincol}.
+
+@item bailout
+Set the bailout value. Default value is 10.0.
+
+@item maxiter
+Set the maximum of iterations performed by the rendering
+algorithm. Default value is 7189.
+
+@item outer
+Set outer coloring mode.
+It shall assume one of following values:
+@table @option
+@item iteration_count
+Set iteration cound mode.
+@item normalized_iteration_count
+set normalized iteration count mode.
+@end table
+Default value is @var{normalized_iteration_count}.
+
+@item rate, r
+Set frame rate, expressed as number of frames per second. Default
+value is "25".
+
+@item size, s
+Set frame size. For the syntax of this option, check the "Video
+size" section in the ffmpeg-utils manual. Default value is "640x480".
+
+@item start_scale
+Set the initial scale value. Default value is 3.0.
-# correct luminance gamma by a 0.5 factor
-lutyuv=y=gammaval(0.5)
-@end example
+@item start_x
+Set the initial x position. Must be a floating point value between
+-100 and 100. Default value is -0.743643887037158704752191506114774.
-@section negate
+@item start_y
+Set the initial y position. Must be a floating point value between
+-100 and 100. Default value is -0.131825904205311970493132056385139.
+@end table
-Negate input video.
+@section mptestsrc
-This filter accepts an integer in input, if non-zero it negates the
-alpha component (if available). The default value in input is 0.
+Generate various test patterns, as generated by the MPlayer test filter.
-@section noformat
+The size of the generated video is fixed, and is 256x256.
+This source is useful in particular for testing encoding features.
-Force libavfilter not to use any of the specified pixel formats for the
-input to the next filter.
+This source accepts the following options:
-This filter accepts the following parameters:
@table @option
-@item pix_fmts
-A '|'-separated list of pixel format names, for example
-"pix_fmts=yuv420p|monow|rgb24".
+@item 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
+@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
+number or a valid video frame rate abbreviation. The default value is
+"25".
+
+@item duration, d
+Set the video duration of the sourced video. The accepted syntax is:
+@example
+[-]HH:MM:SS[.m...]
+[-]S+[.m...]
+@end example
+See also the function @code{av_parse_time()}.
+
+If not specified, or the expressed duration is negative, the video is
+supposed to be generated forever.
+
+@item test, t
+
+Set the number or the name of the test to perform. Supported tests are:
+@table @option
+@item dc_luma
+@item dc_chroma
+@item freq_luma
+@item freq_chroma
+@item amp_luma
+@item amp_chroma
+@item cbp
+@item mv
+@item ring1
+@item ring2
+@item all
+@end table
+Default value is "all", which will cycle through the list of all tests.
@end table
-Some examples follow:
+For example the following:
@example
-# 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
+testsrc=t=dc_luma
@end example
-@section null
-
-Pass the video source unchanged to the output.
+will generate a "dc_luma" test pattern.
-@section ocv
+@section frei0r_src
-Apply video transform using libopencv.
+Provide a frei0r source.
-To enable this filter install libopencv library and headers and
-configure Libav with --enable-libopencv.
+To enable compilation of this filter you need to install the frei0r
+header and configure FFmpeg with @code{--enable-frei0r}.
-This filter accepts the following parameters:
+This source accepts the following options:
@table @option
+@item size
+The size of the video to generate. For the syntax of this option, check the
+"Video size" section in the ffmpeg-utils manual.
+
+@item framerate
+Framerate of the generated video, may be a string of the form
+@var{num}/@var{den} or a frame rate abbreviation.
+
@item filter_name
-The name of the libopencv filter to apply.
+The name to the frei0r source to load. For more information regarding frei0r and
+how to set the parameters read the section @ref{frei0r} in the description of
+the video filters.
@item filter_params
-The parameters to pass to the libopencv filter. If not specified the default
-values are assumed.
+A '|'-separated list of parameters to pass to the frei0r source.
@end table
-Refer to the official libopencv documentation for more precise
-information:
-@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
+For example, to generate a frei0r partik0l source with size 200x200
+and frame rate 10 which is overlayed on the overlay filter main input:
+@example
+frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
+@end example
-Follows the list of supported libopencv filters.
+@section life
-@anchor{dilate}
-@subsection dilate
+Generate a life pattern.
-Dilate an image by using a specific structuring element.
-This filter corresponds to the libopencv function @code{cvDilate}.
+This source is based on a generalization of John Conway's life game.
-It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
+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.
-@var{struct_el} represents a structuring element, and has the syntax:
-@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
+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 @option{rule} option allows to specify
+the rule to adopt.
-@var{cols} and @var{rows} represent the number of columns and rows of
-the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
-point, and @var{shape} the shape for the structuring element, and
-can be one of the values "rect", "cross", "ellipse", "custom".
+This source accepts the following options:
-If the value for @var{shape} is "custom", it must be followed by a
-string of the form "=@var{filename}". The file with name
-@var{filename} is assumed to represent a binary image, with each
-printable character corresponding to a bright pixel. When a custom
-@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
-or columns and rows of the read file are assumed instead.
+@table @option
+@item 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.
-The default value for @var{struct_el} is "3x3+0x0/rect".
+If this option is not specified, the initial grid is generated
+randomly.
-@var{nb_iterations} specifies the number of times the transform is
-applied to the image, and defaults to 1.
+@item rate, r
+Set the video rate, that is the number of frames generated per second.
+Default is 25.
+
+@item 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.
+
+@item 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.
+
+@item rule
+Set the life rule.
+
+A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
+where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
+@var{NS} specifies the number of alive neighbor cells which make a
+live cell stay alive, and @var{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 = @code{(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.
-Follow some example:
+@item size, s
+Set the size of the output video. For the syntax of this option, check the
+"Video size" section in the ffmpeg-utils manual.
+
+If @option{filename} is specified, the size is set by default to the
+same size of the input file. If @option{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).
+
+@item stitch
+If set to 1, stitch the left and right grid edges together, and the
+top and bottom edges also. Defaults to 1.
+
+@item mold
+Set cell mold speed. If set, a dead cell will go from @option{death_color} to
+@option{mold_color} with a step of @option{mold}. @option{mold} can have a
+value from 0 to 255.
+
+@item life_color
+Set the color of living (or new born) cells.
+
+@item death_color
+Set the color of dead cells. If @option{mold} is set, this is the first color
+used to represent a dead cell.
+
+@item mold_color
+Set mold color, for definitely dead and moldy cells.
+
+For the syntax of these 3 color options, check the "Color" section in the
+ffmpeg-utils manual.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Read a grid from @file{pattern}, and center it on a grid of size
+300x300 pixels:
@example
-# use the default values
-ocv=dilate
+life=f=pattern:s=300x300
+@end example
-# dilate using a structuring element with a 5x5 cross, iterate two times
-ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
+@item
+Generate a random grid of size 200x200, with a fill ratio of 2/3:
+@example
+life=ratio=2/3:s=200x200
+@end example
-# 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
+@item
+Specify a custom rule for evolving a randomly generated grid:
+@example
+life=rule=S14/B34
@end example
-@subsection erode
+@item
+Full example with slow death effect (mold) using @command{ffplay}:
+@example
+ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
+@end example
+@end itemize
-Erode an image by using a specific structuring element.
-This filter corresponds to the libopencv function @code{cvErode}.
+@anchor{color}
+@anchor{haldclutsrc}
+@anchor{nullsrc}
+@anchor{rgbtestsrc}
+@anchor{smptebars}
+@anchor{smptehdbars}
+@anchor{testsrc}
+@section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
-The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
-with the same syntax and semantics as the @ref{dilate} filter.
+The @code{color} source provides an uniformly colored input.
-@subsection smooth
+The @code{haldclutsrc} source provides an identity Hald CLUT. See also
+@ref{haldclut} filter.
-Smooth the input video.
+The @code{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 filter takes the following parameters:
-@var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
+The @code{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.
-@var{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".
+The @code{smptebars} source generates a color bars pattern, based on
+the SMPTE Engineering Guideline EG 1-1990.
-@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
-parameters whose meanings depend on smooth type. @var{param1} and
-@var{param2} accept integer positive values or 0, @var{param3} and
-@var{param4} accept float values.
+The @code{smptehdbars} source generates a color bars pattern, based on
+the SMPTE RP 219-2002.
-The default value for @var{param1} is 3, the default value for the
-other parameters is 0.
+The @code{testsrc} source generates a test video pattern, showing a
+color pattern, a scrolling gradient and a timestamp. This is mainly
+intended for testing purposes.
-These parameters correspond to the parameters assigned to the
-libopencv function @code{cvSmooth}.
+The sources accept the following options:
-@anchor{overlay}
-@section overlay
+@table @option
-Overlay one video on top of another.
+@item color, c
+Specify the color of the source, only available in the @code{color}
+source. For the syntax of this option, check the "Color" section in the
+ffmpeg-utils manual.
-It takes two inputs and one output, the first input is the "main"
-video on which the second input is overlayed.
+@item level
+Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
+source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
+pixels to be used as identity matrix for 3D lookup tables. Each component is
+coded on a @code{1/(N*N)} scale.
-This filter accepts the following parameters:
+@item size, s
+Specify the size of the sourced video. For the syntax of this option, check the
+"Video size" section in the ffmpeg-utils manual. The default value is
+"320x240".
-@table @option
+This option is not available with the @code{haldclutsrc} filter.
-@item x
-The horizontal position of the left edge of the overlaid video on the main video.
+@item 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
+@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
+number or a valid video frame rate abbreviation. The default value is
+"25".
-@item y
-The vertical position of the top edge of the overlaid video on the main video.
+@item sar
+Set the sample aspect ratio of the sourced video.
+
+@item duration, d
+Set the video duration of the sourced video. The accepted syntax is:
+@example
+[-]HH[:MM[:SS[.m...]]]
+[-]S+[.m...]
+@end example
+See also the function @code{av_parse_time()}.
+
+If not specified, or the expressed duration is negative, the video is
+supposed to be generated forever.
+@item decimals, n
+Set the number of decimals to show in the timestamp, only available in the
+@code{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.
@end table
-The parameters are expressions containing the following parameters:
+For example the following:
+@example
+testsrc=duration=5.3:size=qcif:rate=10
+@end example
+
+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.
+@example
+color=c=red@@0.2:s=qcif:r=10
+@end example
+
+If the input content is to be ignored, @code{nullsrc} can be used. The
+following command generates noise in the luminance plane by employing
+the @code{geq} filter:
+@example
+nullsrc=s=256x256, geq=random(1)*255:128:128
+@end example
+
+@subsection Commands
+
+The @code{color} source supports the following commands:
@table @option
-@item main_w, main_h
-main input width and height
+@item c, color
+Set the color of the created image. Accepts the same syntax of the
+corresponding @option{color} option.
+@end table
-@item W, H
-same as @var{main_w} and @var{main_h}
+@c man end VIDEO SOURCES
-@item overlay_w, overlay_h
-overlay input width and height
+@chapter Video Sinks
+@c man begin VIDEO SINKS
-@item w, h
-same as @var{overlay_w} and @var{overlay_h}
+Below is a description of the currently available video sinks.
-@item eof_action
-The action to take when EOF is encountered on the secondary input, accepts one
-of the following values:
+@section 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 @file{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 @code{avfilter_init_filter} for initialization.
+
+@section 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.
+
+@c man end VIDEO SINKS
+
+@chapter Multimedia Filters
+@c man begin MULTIMEDIA FILTERS
+
+Below is a description of the currently available multimedia filters.
+
+@section 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:
@table @option
-@item repeat
-repeat the last frame (the default)
-@item endall
-end both streams
-@item pass
-pass through the main input
-@end table
+@item mode, m
+Set the vectorscope mode.
-@end table
+Available values are:
+@table @samp
+@item lissajous
+Lissajous rotated by 45 degrees.
-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 @var{setpts=PTS-STARTPTS} filter to
-have them begin in the same zero timestamp, as it does the example for
-the @var{movie} filter.
+@item lissajous_xy
+Same as above but not rotated.
+@end table
-Follow some examples:
-@example
-# draw the overlay at 10 pixels from the bottom right
-# corner of the main video.
-overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
+Default value is @samp{lissajous}.
-# insert a transparent PNG logo in the bottom left corner of the input
-avconv -i input -i logo -filter_complex 'overlay=x=10:y=main_h-overlay_h-10' output
+@item size, s
+Set the video size for the output. For the syntax of this option, check the "Video size"
+section in the ffmpeg-utils manual. Default value is @code{400x400}.
-# insert 2 different transparent PNG logos (second logo on bottom
-# right corner):
-avconv -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
+@item rate, r
+Set the output frame rate. Default value is @code{25}.
+
+@item rc
+@item gc
+@item bc
+Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
+Allowed range is @code{[0, 255]}.
+
+@item rf
+@item gf
+@item bf
+Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
+Allowed range is @code{[0, 255]}.
+
+@item zoom
+Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
+@end table
-# add a transparent color layer on top of the main video,
-# WxH specifies the size of the main input to the overlay filter
-color=red@.3:WxH [over]; [in][over] overlay [out]
+@subsection Examples
-# mask 10-20 seconds of a video by applying the delogo filter to a section
-avconv -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
--vf '[in]split[split_main][split_delogo];[split_delogo]trim=start=360:end=371,delogo=0:0:640:480[delogoed];[split_main][delogoed]overlay=eof_action=pass[out]'
-masked.avi
+@itemize
+@item
+Complete example using @command{ffplay}:
+@example
+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]'
@end example
+@end itemize
-You can chain together more overlays but the efficiency of such
-approach is yet to be tested.
+@section concat
-@section pad
+Concatenate audio and video streams, joining them together one after the
+other.
-Add paddings to the input image, and places the original input at the
-given coordinates @var{x}, @var{y}.
+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.
-This filter accepts the following parameters:
+The filter accepts the following options:
@table @option
-@item width, height
-
-Specify the size of the output image with the paddings added. If the
-value for @var{width} or @var{height} is 0, the corresponding input size
-is used for the output.
-
-The @var{width} expression can reference the value set by the
-@var{height} expression, and vice versa.
-The default value of @var{width} and @var{height} is 0.
+@item n
+Set the number of segments. Default is 2.
-@item x, y
+@item v
+Set the number of output video streams, that is also the number of video
+streams in each segment. Default is 1.
-Specify the offsets where to place the input image in the padded area
-with respect to the top/left border of the output image.
+@item a
+Set the number of output audio streams, that is also the number of video
+streams in each segment. Default is 0.
-The @var{x} expression can reference the value set by the @var{y}
-expression, and vice versa.
+@item unsafe
+Activate unsafe mode: do not fail if segments have a different format.
-The default value of @var{x} and @var{y} is 0.
+@end table
-@item color
+The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
+@var{a} audio outputs.
-Specify the color of the padded area, it can be the name of a color
-(case insensitive match) or a 0xRRGGBB[AA] sequence.
+There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
+segment, in the same order as the outputs, then the inputs for the second
+segment, etc.
-The default value of @var{color} is "black".
+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.
-@end table
+For this filter to work correctly, all segments must start at timestamp 0.
-The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
-expressions containing the following constants:
+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.
-@table @option
-@item E, PI, PHI
-the corresponding mathematical approximated values for e
-(euler number), pi (greek PI), phi (golden ratio)
+Different frame rates are acceptable but will result in variable frame rate
+at output; be sure to configure the output file to handle it.
-@item in_w, in_h
-the input video width and height
+@subsection Examples
-@item iw, ih
-same as @var{in_w} and @var{in_h}
+@itemize
+@item
+Concatenate an opening, an episode and an ending, all in bilingual version
+(video in stream 0, audio in streams 1 and 2):
+@example
+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
+@end example
-@item out_w, out_h
-the output width and height, that is the size of the padded area as
-specified by the @var{width} and @var{height} expressions
+@item
+Concatenate two parts, handling audio and video separately, using the
+(a)movie sources, and adjusting the resolution:
+@example
+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]
+@end example
+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.
-@item ow, oh
-same as @var{out_w} and @var{out_h}
+@end itemize
-@item x, y
-x and y offsets as specified by the @var{x} and @var{y}
-expressions, or NAN if not yet specified
+@section ebur128
-@item a
-input display aspect ratio, same as @var{iw} / @var{ih}
+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 @code{M}), Short-term loudness (@code{S}),
+Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
-@item hsub, vsub
-horizontal and vertical chroma subsample values. For example for the
-pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
-@end table
+The filter also has a video output (see the @var{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).
-Some examples follow:
+More information about the Loudness Recommendation EBU R128 on
+@url{http://tech.ebu.ch/loudness}.
-@example
-# 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=width=640:height=480:x=0:y=40:color=violet
+The filter accepts the following options:
-# pad the input to get an output with dimensions increased bt 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"
+@table @option
-# 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"
+@item 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 @code{0}.
-# pad the input to get a final w/h ratio of 16:9
-pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
+@item size
+Set the video size. This option is for video only. For the syntax of this
+option, check the "Video size" section in the ffmpeg-utils manual. Default
+and minimum resolution is @code{640x480}.
-# 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"
-@end example
+@item meter
+Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
+@code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
+other integer value between this range is allowed.
-@section pixdesctest
+@item metadata
+Set metadata injection. If set to @code{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 @code{lavfi.r128.}.
-Pixel format descriptor test filter, mainly useful for internal
-testing. The output video should be equal to the input video.
+Default is @code{0}.
-For example:
-@example
-format=monow, pixdesctest
-@end example
+@item framelog
+Force the frame logging level.
-can be used to test the monowhite pixel format descriptor definition.
+Available values are:
+@table @samp
+@item info
+information logging level
+@item verbose
+verbose logging level
+@end table
-@anchor{scale}
-@section scale
+By default, the logging level is set to @var{info}. If the @option{video} or
+the @option{metadata} options are set, it switches to @var{verbose}.
-Scale the input video and/or convert the image format.
+@item peak
+Set peak mode(s).
-This filter accepts the following options:
+Available modes can be cumulated (the option is a @code{flag} type). Possible
+values are:
+@table @samp
+@item none
+Disable any peak mode (default).
+@item sample
+Enable sample-peak mode.
+
+Simple peak mode looking for the higher sample value. It logs a message
+for sample-peak (identified by @code{SPK}).
+@item true
+Enable true-peak mode.
+
+If enabled, the peak lookup is done on an over-sampled version of the input
+stream for better peak accuracy. It logs a message for true-peak.
+(identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
+This mode requires a build with @code{libswresample}.
+@end table
-@table @option
+@end table
-@item w
-Output video width.
+@subsection Examples
-@item h
-Output video height.
+@itemize
+@item
+Real-time graph using @command{ffplay}, with a EBU scale meter +18:
+@example
+ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
+@end example
-@end table
+@item
+Run an analysis with @command{ffmpeg}:
+@example
+ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
+@end example
+@end itemize
-The parameters @var{w} and @var{h} are expressions containing
-the following constants:
+@section interleave, ainterleave
-@table @option
-@item E, PI, PHI
-the corresponding mathematical approximated values for e
-(euler number), pi (greek PI), phi (golden ratio)
+Temporally interleave frames from several inputs.
-@item in_w, in_h
-the input width and height
+@code{interleave} works with video inputs, @code{ainterleave} with audio.
-@item iw, ih
-same as @var{in_w} and @var{in_h}
+These filters read frames from several inputs and send the oldest
+queued frame to the output.
-@item out_w, out_h
-the output (cropped) width and height
+Input streams must have a well defined, monotonically increasing frame
+timestamp values.
-@item ow, oh
-same as @var{out_w} and @var{out_h}
+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.
-@item a
-same as @var{iw} / @var{ih}
+For example consider the case when one input is a @code{select} filter
+which always drop input frames. The @code{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.
-@item sar
-input sample aspect ratio
+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.
-@item dar
-input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
+These filters accept the following options:
-@item hsub, vsub
-horizontal and vertical chroma subsample values. For example for the
-pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+@table @option
+@item nb_inputs, n
+Set the number of different inputs, it is 2 by default.
@end table
-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.
+@subsection Examples
-If the value for @var{w} or @var{h} is 0, the respective input
-size is used for the output.
+@itemize
+@item
+Interleave frames belonging to different streams using @command{ffmpeg}:
+@example
+ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
+@end example
-If the value for @var{w} or @var{h} is -1, the scale filter will use, for the
-respective output size, a value that maintains the aspect ratio of the input
-image.
+@item
+Add flickering blur effect:
+@example
+select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
+@end example
+@end itemize
-The default value of @var{w} and @var{h} is 0.
+@section perms, aperms
-Some examples follow:
-@example
-# scale the input video to a size of 200x100.
-scale=w=200:h=100
+Set read/write permissions for the output frames.
-# 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
+These filters are mainly aimed at developers to test direct path in the
+following filter in the filtergraph.
-# scale the input to half size
-scale=w=iw/2:h=ih/2
+The filters accept the following options:
-# increase the width, and set the height to the same size
-scale=3/2*iw:ow
+@table @option
+@item mode
+Select the permissions mode.
-# seek for Greek harmony
-scale=iw:1/PHI*iw
-scale=ih*PHI:ih
+It accepts the following values:
+@table @samp
+@item none
+Do nothing. This is the default.
+@item ro
+Set all the output frames read-only.
+@item rw
+Set all the output frames directly writable.
+@item toggle
+Make the frame read-only if writable, and writable if read-only.
+@item random
+Set each output frame read-only or writable randomly.
+@end table
-# increase the height, and set the width to 3/2 of the height
-scale=w=3/2*oh:h=3/5*ih
+@item seed
+Set the seed for the @var{random} mode, must be an integer included between
+@code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
+@code{-1}, the filter will try to use a good random seed on a best effort
+basis.
+@end table
-# increase the size, but make the size a multiple of the chroma
-scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
+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 @ref{format} or @ref{aformat} filter before the
+perms/aperms filter can avoid this problem.
-# increase the width to a maximum of 500 pixels, keep the same input aspect ratio
-scale=w='min(500\, iw*3/2):h=-1'
-@end example
+@section select, aselect
-@section select
Select frames to pass in output.
This filter accepts the following options:
@table @option
-@item expr
-An expression, which is evaluated for each input frame. If the expression is
-evaluated to a non-zero value, the frame is selected and passed to the output,
-otherwise it is discarded.
+@item expr, e
+Set expression, which is evaluated for each input frame.
-@end table
+If the expression is evaluated to zero, the frame is discarded.
-The expression can contain the following constants:
+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
+@code{ceil(val)-1}, assuming that the input index starts from 0.
-@table @option
-@item PI
-Greek PI
+For example a value of @code{1.2} corresponds to the output with index
+@code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
-@item PHI
-golden ratio
+@item 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.
+@end table
-@item E
-Euler number
+The expression can contain the following constants:
+@table @option
@item n
the sequential number of the filtered frame, starting from 0
@item start_t
the time of the first video frame in the video, NAN if undefined
-@item pict_type
+@item pict_type @emph{(video only)}
the type of the filtered frame, can assume one of the following
values:
@table @option
@item BI
@end table
-@item interlace_type
+@item interlace_type @emph{(video only)}
the frame interlace type, can assume one of the following values:
@table @option
@item PROGRESSIVE
the frame is bottom-field-first
@end table
-@item key
-1 if the filtered frame is a key-frame, 0 otherwise
-
-@end table
-
-The default value of the select expression is "1".
-
-Some examples follow:
-
-@example
-# select all frames in input
-select
-
-# the above is the same as:
-select=expr=1
-
-# skip all frames:
-select=expr=0
-
-# select only I-frames
-select='expr=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)'
-@end example
-
-@anchor{setdar}
-@section setdar
-
-Set the Display Aspect Ratio for the filter output video.
+@item consumed_sample_n @emph{(audio only)}
+the number of selected samples before the current frame
-This is done by changing the specified Sample (aka Pixel) Aspect
-Ratio, according to the following equation:
-@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
+@item samples_n @emph{(audio only)}
+the number of samples in the current frame
-Keep in mind that this 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.
+@item sample_rate @emph{(audio only)}
+the input sample rate
-This filter accepts the following options:
+@item key
+1 if the filtered frame is a key-frame, 0 otherwise
-@table @option
+@item pos
+the position in the file of the filtered frame, -1 if the information
+is not available (e.g. for synthetic video)
-@item dar
-Output display aspect ratio.
+@item scene @emph{(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)
@end table
-The parameter @var{dar} is an expression containing
-the following constants:
-
-@table @option
-@item E, PI, PHI
-the corresponding mathematical approximated values for e
-(euler number), pi (greek PI), phi (golden ratio)
-
-@item w, h
-the input width and height
-
-@item a
-same as @var{w} / @var{h}
-
-@item sar
-input sample aspect ratio
-
-@item dar
-input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
+The default value of the select expression is "1".
-@item hsub, vsub
-horizontal and vertical chroma subsample values. For example for the
-pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
-@end table
+@subsection Examples
-For example to change the display aspect ratio to 16:9, specify:
+@itemize
+@item
+Select all frames in input:
@example
-setdar=dar=16/9
-# the above is equivalent to
-setdar=dar=1.77777
+select
@end example
-See also the @ref{setsar} filter documentation.
-
-@section setpts
-
-Change the PTS (presentation timestamp) of the input video frames.
-
-This filter accepts the following options:
-
-@table @option
-
-@item expr
-The expression which is evaluated for each frame to construct its timestamp.
-
-@end table
-
-The expression is evaluated through the eval API and can contain the following
-constants:
-
-@table @option
-@item PTS
-the presentation timestamp in input
-
-@item PI
-Greek PI
-
-@item PHI
-golden ratio
-
-@item E
-Euler number
-
-@item N
-the count of the input frame, starting from 0.
-
-@item STARTPTS
-the PTS of the first video frame
-
-@item INTERLACED
-tell if the current frame is interlaced
-
-@item PREV_INPTS
-previous input PTS
-
-@item PREV_OUTPTS
-previous output PTS
-
-@item RTCTIME
-wallclock (RTC) time in microseconds
-
-@item RTCSTART
-wallclock (RTC) time at the start of the movie in microseconds
-
-@item TB
-timebase of the input timestamps
-
-@end table
-
-Some examples follow:
+The example above is the same as:
+@example
+select=1
+@end example
+@item
+Skip all frames:
@example
-# start counting PTS from zero
-setpts=expr=PTS-STARTPTS
+select=0
+@end example
-# fast motion
-setpts=expr=0.5*PTS
+@item
+Select only I-frames:
+@example
+select='eq(pict_type\,I)'
+@end example
-# slow motion
-setpts=2.0*PTS
+@item
+Select one frame every 100:
+@example
+select='not(mod(n\,100))'
+@end example
-# fixed rate 25 fps
-setpts=N/(25*TB)
+@item
+Select only frames contained in the 10-20 time interval:
+@example
+select=between(t\,10\,20)
+@end example
-# fixed rate 25 fps with some jitter
-setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
+@item
+Select only I frames contained in the 10-20 time interval:
+@example
+select=between(t\,10\,20)*eq(pict_type\,I)
+@end example
-# generate timestamps from a "live source" and rebase onto the current timebase
-setpts='(RTCTIME - RTCSTART) / (TB * 1000000)"
+@item
+Select frames with a minimum distance of 10 seconds:
+@example
+select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
@end example
-@anchor{setsar}
-@section setsar
+@item
+Use aselect to select only audio frames with samples number > 100:
+@example
+aselect='gt(samples_n\,100)'
+@end example
-Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
+@item
+Create a mosaic of the first scenes:
+@example
+ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
+@end example
-Note that as a consequence of the application of this filter, the
-output display aspect ratio will change according to the following
-equation:
-@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
+Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
+choice.
-Keep in mind that the sample aspect ratio set by this filter may be
-changed by later filters in the filterchain, e.g. if another "setsar"
-or a "setdar" filter is applied.
+@item
+Send even and odd frames to separate outputs, and compose them:
+@example
+select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
+@end example
+@end itemize
-This filter accepts the following options:
+@section sendcmd, asendcmd
-@table @option
+Send commands to filters in the filtergraph.
-@item sar
-Output sample aspect ratio.
+These filters read commands to be sent to other filters in the
+filtergraph.
-@end table
+@code{sendcmd} must be inserted between two video filters,
+@code{asendcmd} must be inserted between two audio filters, but apart
+from that they act the same way.
-The parameter @var{sar} is an expression containing
-the following constants:
+The specification of commands can be provided in the filter arguments
+with the @var{commands} option, or in a file specified by the
+@var{filename} option.
+These filters accept the following options:
@table @option
-@item E, PI, PHI
-the corresponding mathematical approximated values for e
-(euler number), pi (greek PI), phi (golden ratio)
+@item commands, c
+Set the commands to be read and sent to the other filters.
+@item filename, f
+Set the filename of the commands to be read and sent to the other
+filters.
+@end table
-@item w, h
-the input width and height
+@subsection Commands syntax
-@item a
-same as @var{w} / @var{h}
+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.
-@item sar
-input sample aspect ratio
+An interval is specified by the following syntax:
+@example
+@var{START}[-@var{END}] @var{COMMANDS};
+@end example
-@item dar
-input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
+The time interval is specified by the @var{START} and @var{END} times.
+@var{END} is optional and defaults to the maximum time.
-@item hsub, vsub
-horizontal and vertical chroma subsample values. For example for the
-pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
-@end table
+The current frame time is considered within the specified interval if
+it is included in the interval [@var{START}, @var{END}), that is when
+the time is greater or equal to @var{START} and is lesser than
+@var{END}.
-For example to change the sample aspect ratio to 10:11, specify:
+@var{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:
@example
-setsar=sar=10/11
+[@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
@end example
-@section settb
-
-Set the timebase to use for the output frames timestamps.
-It is mainly useful for testing timebase configuration.
-
-This filter accepts the following options:
+@var{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:
@table @option
+@item 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.
+
+@item 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.
+@end table
-@item expr
-The expression which is evaluated into the output timebase.
+If @var{FLAGS} is not specified, a default value of @code{[enter]} is
+assumed.
-@end table
+@var{TARGET} specifies the target of the command, usually the name of
+the filter class or a specific filter instance name.
-The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
-default timebase), and "intb" (the input timebase).
+@var{COMMAND} specifies the name of the command for the target filter.
-The default value for the input is "intb".
+@var{ARG} is optional and specifies the optional list of argument for
+the given @var{COMMAND}.
-Follow some examples.
+Between one interval specification and another, whitespaces, or
+sequences of characters starting with @code{#} until the end of line,
+are ignored and can be used to annotate comments.
+A simplified BNF description of the commands specification syntax
+follows:
@example
-# set the timebase to 1/25
-settb=expr=1/25
+@var{COMMAND_FLAG} ::= "enter" | "leave"
+@var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
+@var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
+@var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
+@var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
+@var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
+@end example
-# set the timebase to 1/10
-settb=expr=0.1
+@subsection Examples
-#set the timebase to 1001/1000
-settb=1+0.001
+@itemize
+@item
+Specify audio tempo change at second 4:
+@example
+asendcmd=c='4.0 atempo tempo 1.5',atempo
+@end example
-#set the timebase to 2*intb
-settb=2*intb
+@item
+Specify a list of drawtext and hue commands in a file.
+@example
+# 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)
+@end example
-#set the default timebase value
-settb=AVTB
+A filtergraph allowing to read and process the above command list
+stored in a file @file{test.cmd}, can be specified with:
+@example
+sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
@end example
+@end itemize
-@section showinfo
+@anchor{setpts}
+@section setpts, asetpts
-Show a line containing various information for each input video frame.
-The input video is not modified.
+Change the PTS (presentation timestamp) of the input frames.
-The shown line contains a sequence of key/value pairs of the form
-@var{key}:@var{value}.
+@code{setpts} works on video frames, @code{asetpts} on audio frames.
-A description of each shown parameter follows:
+This filter accepts the following options:
@table @option
-@item n
-sequential number of the input frame, starting from 0
-@item 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.
+@item expr
+The expression which is evaluated for each frame to construct its timestamp.
-@item pts_time
-Presentation TimeStamp of the input frame, expressed as a number of
-seconds
+@end table
-@item 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)
+The expression is evaluated through the eval API and can contain the following
+constants:
-@item fmt
-pixel format name
+@table @option
+@item FRAME_RATE
+frame rate, only defined for constant frame-rate video
-@item sar
-sample aspect ratio of the input frame, expressed in the form
-@var{num}/@var{den}
+@item PTS
+the presentation timestamp in input
-@item s
-size of the input frame, expressed in the form
-@var{width}x@var{height}
+@item 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.
-@item i
-interlaced mode ("P" for "progressive", "T" for top field first, "B"
-for bottom field first)
+@item NB_CONSUMED_SAMPLES
+the number of consumed samples, not including the current frame (only
+audio)
-@item iskey
-1 if the frame is a key frame, 0 otherwise
+@item NB_SAMPLES, S
+the number of samples in the current frame (only audio)
-@item 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 @code{AVPictureType} enum and of
-the @code{av_get_picture_type_char} function defined in
-@file{libavutil/avutil.h}.
+@item SAMPLE_RATE, SR
+audio sample rate
-@item checksum
-Adler-32 checksum of all the planes of the input frame
+@item STARTPTS
+the PTS of the first frame
-@item plane_checksum
-Adler-32 checksum of each plane of the input frame, expressed in the form
-"[@var{c0} @var{c1} @var{c2} @var{c3}]"
-@end table
+@item STARTT
+the time in seconds of the first frame
-@section split
+@item INTERLACED
+tell if the current frame is interlaced
-Split input video into several identical outputs.
+@item T
+the time in seconds of the current frame
-The filter accepts a single parameter which specifies the number of outputs. If
-unspecified, it defaults to 2.
+@item POS
+original position in the file of the frame, or undefined if undefined
+for the current frame
-For example
-@example
-avconv -i INPUT -filter_complex split=5 OUTPUT
-@end example
-will create 5 copies of the input video.
+@item PREV_INPTS
+previous input PTS
-@section transpose
+@item PREV_INT
+previous input time in seconds
-Transpose rows with columns in the input video and optionally flip it.
+@item PREV_OUTPTS
+previous output PTS
-This filter accepts the following options:
+@item PREV_OUTT
+previous output time in seconds
-@table @option
+@item RTCTIME
+wallclock (RTC) time in microseconds. This is deprecated, use time(0)
+instead.
-@item dir
-The direction of the transpose.
+@item RTCSTART
+wallclock (RTC) time at the start of the movie in microseconds
+
+@item TB
+timebase of the input timestamps
@end table
-The direction can assume the following values:
+@subsection Examples
-@table @samp
-@item cclock_flip
-Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
+@itemize
+@item
+Start counting PTS from zero
@example
-L.R L.l
-. . -> . .
-l.r R.r
+setpts=PTS-STARTPTS
@end example
-@item clock
-Rotate by 90 degrees clockwise, that is:
+@item
+Apply fast motion effect:
@example
-L.R l.L
-. . -> . .
-l.r r.R
+setpts=0.5*PTS
@end example
-@item cclock
-Rotate by 90 degrees counterclockwise, that is:
+@item
+Apply slow motion effect:
@example
-L.R R.r
-. . -> . .
-l.r L.l
+setpts=2.0*PTS
@end example
-@item clock_flip
-Rotate by 90 degrees clockwise and vertically flip, that is:
+@item
+Set fixed rate of 25 frames per second:
@example
-L.R r.R
-. . -> . .
-l.r l.L
+setpts=N/(25*TB)
@end example
-@end table
-@section trim
-Trim the input so that the output contains one continuous subpart of the input.
+@item
+Set fixed rate 25 fps with some jitter:
+@example
+setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
+@end example
-This filter accepts the following options:
-@table @option
-@item start
-Timestamp (in seconds) of the start of the kept section. I.e. the frame with the
-timestamp @var{start} will be the first frame in the output.
+@item
+Apply an offset of 10 seconds to the input PTS:
+@example
+setpts=PTS+10/TB
+@end example
-@item end
-Timestamp (in seconds) of the first frame that will be dropped. I.e. the frame
-immediately preceding the one with the timestamp @var{end} will be the last
-frame in the output.
+@item
+Generate timestamps from a "live source" and rebase onto the current timebase:
+@example
+setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
+@end example
-@item start_pts
-Same as @var{start}, except this option sets the start timestamp in timebase
-units instead of seconds.
+@item
+Generate timestamps by counting samples:
+@example
+asetpts=N/SR/TB
+@end example
-@item end_pts
-Same as @var{end}, except this option sets the end timestamp in timebase units
-instead of seconds.
+@end itemize
-@item duration
-Maximum duration of the output in seconds.
+@section settb, asettb
-@item start_frame
-Number of the first frame that should be passed to output.
+Set the timebase to use for the output frames timestamps.
+It is mainly useful for testing timebase configuration.
-@item end_frame
-Number of the first frame that should be dropped.
-@end table
+This filter accepts the following options:
-Note that the first two sets of the start/end options and the @option{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.
+@table @option
-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.
+@item expr, tb
+The expression which is evaluated into the output timebase.
-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.
+@end table
+
+The value for @option{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".
+
+@subsection Examples
-Examples:
@itemize
@item
-drop everything except the second minute of input
+Set the timebase to 1/25:
+@example
+settb=expr=1/25
+@end example
+
+@item
+Set the timebase to 1/10:
@example
-avconv -i INPUT -vf trim=60:120
+settb=expr=0.1
@end example
@item
-keep only the first second
+Set the timebase to 1001/1000:
+@example
+settb=1+0.001
+@end example
+
+@item
+Set the timebase to 2*intb:
+@example
+settb=2*intb
+@end example
+
+@item
+Set the default timebase value:
@example
-avconv -i INPUT -vf trim=duration=1
+settb=AVTB
@end example
-
@end itemize
-@section unsharp
-Sharpen or blur the input video.
+@section showspectrum
-It accepts the following parameters:
+Convert input audio to a video output, representing the audio frequency
+spectrum.
+
+The filter accepts the following options:
@table @option
+@item size, s
+Specify the video size for the output. For the syntax of this option, check
+the "Video size" section in the ffmpeg-utils manual. Default value is
+@code{640x512}.
-@item luma_msize_x
-Set the luma matrix horizontal size. It can be an integer between 3
-and 13, default value is 5.
+@item slide
+Specify if the spectrum should slide along the window. Default value is
+@code{0}.
-@item luma_msize_y
-Set the luma matrix vertical size. It can be an integer between 3
-and 13, default value is 5.
+@item mode
+Specify display mode.
+
+It accepts the following values:
+@table @samp
+@item combined
+all channels are displayed in the same row
+@item separate
+all channels are displayed in separate rows
+@end table
-@item luma_amount
-Set the luma effect strength. It can be a float number between -2.0
-and 5.0, default value is 1.0.
+Default value is @samp{combined}.
-@item chroma_msize_x
-Set the chroma matrix horizontal size. It can be an integer between 3
-and 13, default value is 5.
+@item color
+Specify display color mode.
+
+It accepts the following values:
+@table @samp
+@item channel
+each channel is displayed in a separate color
+@item intensity
+each channel is is displayed using the same color scheme
+@end table
-@item chroma_msize_y
-Set the chroma matrix vertical size. It can be an integer between 3
-and 13, default value is 5.
+Default value is @samp{channel}.
-@item chroma_amount
-Set the chroma effect strength. It can be a float number between -2.0
-and 5.0, default value is 0.0.
+@item scale
+Specify scale used for calculating intensity color values.
+It accepts the following values:
+@table @samp
+@item lin
+linear
+@item sqrt
+square root, default
+@item cbrt
+cubic root
+@item log
+logarithmic
@end table
-Negative values for the amount will blur the input video, while positive
-values will sharpen. All parameters are optional and default to the
-equivalent of the string '5:5:1.0:5:5:0.0'.
+Default value is @samp{sqrt}.
-@example
-# Strong luma sharpen effect parameters
-unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
+@item saturation
+Set saturation modifier for displayed colors. Negative values provide
+alternative color scheme. @code{0} is no saturation at all.
+Saturation must be in [-10.0, 10.0] range.
+Default value is @code{1}.
-# Strong blur of both luma and chroma parameters
-unsharp=7:7:-2:7:7:-2
+@item win_func
+Set window function.
-# Use the default values with @command{avconv}
-./avconv -i in.avi -vf "unsharp" out.mp4
-@end example
+It accepts the following values:
+@table @samp
+@item none
+No samples pre-processing (do not expect this to be faster)
+@item hann
+Hann window
+@item hamming
+Hamming window
+@item blackman
+Blackman window
+@end table
-@section vflip
+Default value is @code{hann}.
+@end table
-Flip the input video vertically.
+The usage is very similar to the showwaves filter; see the examples in that
+section.
+
+@subsection Examples
+@itemize
+@item
+Large window with logarithmic color scaling:
@example
-./avconv -i in.avi -vf "vflip" out.avi
+showspectrum=s=1280x480:scale=log
@end example
-@section yadif
+@item
+Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
+@example
+ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
+ [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
+@end example
+@end itemize
-Deinterlace the input video ("yadif" means "yet another deinterlacing
-filter").
+@section showwaves
-This filter accepts the following options:
+Convert input audio to a video output, representing the samples waves.
+
+The filter accepts the following options:
@table @option
+@item size, s
+Specify the video size for the output. For the syntax of this option, check
+the "Video size" section in the ffmpeg-utils manual. Default value
+is "600x240".
@item mode
-The interlacing mode to adopt, accepts one of the following values:
+Set display mode.
-@table @option
-@item 0
-output 1 frame for each frame
-@item 1
-output 1 frame for each field
-@item 2
-like 0 but skips spatial interlacing check
-@item 3
-like 1 but skips spatial interlacing check
+Available values are:
+@table @samp
+@item point
+Draw a point for each sample.
+
+@item line
+Draw a vertical line for each sample.
@end table
-Default value is 0.
+Default value is @code{point}.
-@item parity
-The picture field parity assumed for the input interlaced video, accepts one of
-the following values:
+@item 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 @var{rate}
+is not explicitly specified.
-@table @option
-@item 0
-assume top field first
-@item 1
-assume bottom field first
-@item -1
-enable automatic detection
-@end table
+@item rate, r
+Set the (approximate) output frame rate. This is done by setting the
+option @var{n}. Default value is "25".
-Default value is -1.
-If interlacing is unknown or decoder does not export this information,
-top field first will be assumed.
+@end table
-@item auto
-Whether deinterlacer should trust the interlaced flag and only deinterlace
-frames marked as interlaced
+@subsection Examples
-@table @option
-@item 0
-deinterlace all frames
-@item 1
-only deinterlace frames marked as interlaced
-@end table
+@itemize
+@item
+Output the input file audio and the corresponding video representation
+at the same time:
+@example
+amovie=a.mp3,asplit[out0],showwaves[out1]
+@end example
-Default value is 0.
+@item
+Create a synthetic signal and show it with showwaves, forcing a
+frame rate of 30 frames per second:
+@example
+aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
+@end example
+@end itemize
-@end table
+@section split, asplit
-@c man end VIDEO FILTERS
+Split input into several identical outputs.
-@chapter Video Sources
-@c man begin VIDEO SOURCES
+@code{asplit} works with audio input, @code{split} with video.
-Below is a description of the currently available video sources.
+The filter accepts a single parameter which specifies the number of outputs. If
+unspecified, it defaults to 2.
-@section buffer
+@subsection Examples
-Buffer video frames, and make them available to the filter chain.
+@itemize
+@item
+Create two separate outputs from the same input:
+@example
+[in] split [out0][out1]
+@end example
-This source is mainly intended for a programmatic use, in particular
-through the interface defined in @file{libavfilter/vsrc_buffer.h}.
+@item
+To create 3 or more outputs, you need to specify the number of
+outputs, like in:
+@example
+[in] asplit=3 [out0][out1][out2]
+@end example
-This filter accepts the following parameters:
+@item
+Create two separate outputs from the same input, one cropped and
+one padded:
+@example
+[in] split [splitout1][splitout2];
+[splitout1] crop=100:100:0:0 [cropout];
+[splitout2] pad=200:200:100:100 [padout];
+@end example
-@table @option
+@item
+Create 5 copies of the input audio with @command{ffmpeg}:
+@example
+ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
+@end example
+@end itemize
-@item width
-Input video width.
+@section zmq, azmq
-@item height
-Input video height.
+Receive commands sent through a libzmq client, and forward them to
+filters in the filtergraph.
-@item pix_fmt
-Name of the input video pixel format.
+@code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
+must be inserted between two video filters, @code{azmq} between two
+audio filters.
-@item time_base
-The time base used for input timestamps.
+To enable these filters you need to install the libzmq library and
+headers and configure FFmpeg with @code{--enable-libzmq}.
-@item sar
-Sample (pixel) aspect ratio of the input video.
+For more information about libzmq see:
+@url{http://www.zeromq.org/}
-@end table
+The @code{zmq} and @code{azmq} filters work as a libzmq server, which
+receives messages sent through a network interface defined by the
+@option{bind_address} option.
-For example:
+The received message must be in the form:
@example
-buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
+@var{TARGET} @var{COMMAND} [@var{ARG}]
@end example
-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).
-
-@section color
+@var{TARGET} specifies the target of the command, usually the name of
+the filter class or a specific filter instance name.
-Provide an uniformly colored input.
+@var{COMMAND} specifies the name of the command for the target filter.
-It accepts the following parameters:
+@var{ARG} is optional and specifies the optional argument list for the
+given @var{COMMAND}.
-@table @option
+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:
+@example
+@var{ERROR_CODE} @var{ERROR_REASON}
+@var{MESSAGE}
+@end example
-@item color
-Specify the color of the 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".
+@var{MESSAGE} is optional.
-@item size
-Specify the size of the sourced video, it may be a string of the form
-@var{width}x@var{height}, or the name of a size abbreviation. The
-default value is "320x240".
+@subsection Examples
-@item framerate
-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
-@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
-number or a valid video frame rate abbreviation. The default value is
-"25".
+Look at @file{tools/zmqsend} for an example of a zmq client which can
+be used to send commands processed by these filters.
-@end table
+Consider the following filtergraph generated by @command{ffplay}
+@example
+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 "
+@end example
-For example 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, which will be overlayed over the source connected
-to the pad with identifier "in".
+To change the color of the left side of the video, the following
+command can be used:
+@example
+echo Parsed_color_0 c yellow | tools/zmqsend
+@end example
+To change the right side:
@example
-"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
+echo Parsed_color_1 c pink | tools/zmqsend
@end example
-@section movie
+@c man end MULTIMEDIA FILTERS
+
+@chapter Multimedia Sources
+@c man begin MULTIMEDIA SOURCES
+
+Below is a description of the currently available multimedia sources.
-Read a video stream from a movie container.
+@section amovie
-Note that this source is a hack that bypasses the standard input path. It can be
-useful in applications that do not support arbitrary filter graphs, but its use
-is discouraged in those that do. Specifically in @command{avconv} this filter
-should never be used, the @option{-filter_complex} option fully replaces it.
+This is the same as @ref{movie} source, except it selects an audio
+stream by default.
+
+@anchor{movie}
+@section movie
+
+Read audio and/or video stream(s) from a movie container.
This filter accepts the following options:
@table @option
-
@item filename
The name of the resource to read (not necessarily a file but also a device or a
stream accessed through some protocol).
@code{av_strtod} so the numerical value may be suffixed by an IS
postfix. Default value is "0".
+@item 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".
+
@item 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".
+value is "-1". Deprecated. If the filter is called "amovie", it will select
+audio instead of video.
+
+@item 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.
@end table
This filter allows to overlay a second video on top of main input of
movie --> scale--> deltapts1 -------+
@end example
-Some examples follow:
-@example
-# 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 [movie];
-[in] setpts=PTS-STARTPTS, [movie] 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 [movie];
-[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
-
-@end example
-
-@section nullsrc
-
-Null video source, never return images. It is mainly useful as a
-template and to be employed in analysis / debugging tools.
-
-It accepts as optional parameter a string of the form
-@var{width}:@var{height}:@var{timebase}.
-
-@var{width} and @var{height} specify the size of the configured
-source. The default values of @var{width} and @var{height} are
-respectively 352 and 288 (corresponding to the CIF size format).
-
-@var{timebase} specifies an arithmetic expression representing a
-timebase. The expression can contain the constants "PI", "E", "PHI",
-"AVTB" (the default timebase), and defaults to the value "AVTB".
-
-@section frei0r_src
-
-Provide a frei0r source.
-
-To enable compilation of this filter you need to install the frei0r
-header and configure Libav with --enable-frei0r.
-
-This source accepts the following options:
-
-@table @option
-
-@item size
-The size of the video to generate, may be a string of the form
-@var{width}x@var{height} or a frame size abbreviation.
-
-@item framerate
-Framerate of the generated video, may be a string of the form
-@var{num}/@var{den} or a frame rate abbreviation.
-
-@item filter_name
-The name to the frei0r source to load. For more information regarding frei0r and
-how to set the parameters read the section @ref{frei0r} in the description of
-the video filters.
-
-@item filter_params
-A '|'-separated list of parameters to pass to the frei0r source.
-
-@end table
+@subsection Examples
-Some examples follow:
+@itemize
+@item
+Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
+on top of the input labelled as "in":
@example
-# generate a frei0r partik0l source with size 200x200 and framerate 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
+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]
@end example
-@section rgbtestsrc, testsrc
-
-The @code{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 @code{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:
-
-@table @option
-
-@item size, s
-Specify the size of the sourced video, it may be a string of the form
-@var{width}x@var{height}, or the name of a size abbreviation. The
-default value is "320x240".
-
-@item 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
-@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
-number or a valid video frame rate abbreviation. The default value is
-"25".
-
-@item sar
-Set the sample aspect ratio of the sourced video.
-
-@item duration
-Set the video duration of the sourced video. The accepted syntax is:
+@item
+Read from a video4linux2 device, and overlay it on top of the input
+labelled as "in":
@example
-[-]HH[:MM[:SS[.m...]]]
-[-]S+[.m...]
+movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
+[in] setpts=PTS-STARTPTS [main];
+[main][over] overlay=16:16 [out]
@end example
-See also the function @code{av_parse_time()}.
-
-If not specified, or the expressed duration is negative, the video is
-supposed to be generated forever.
-@end table
-For example the following:
+@item
+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":
@example
-testsrc=duration=5.3:size=qcif:rate=10
+movie=dvd.vob:s=v:0+#0x81 [video] [audio]
@end example
+@end itemize
-will generate a video with a duration of 5.3 seconds, with size
-176x144 and a framerate of 10 frames per second.
-
-@c man end VIDEO SOURCES
-
-@chapter Video Sinks
-@c man begin VIDEO SINKS
-
-Below is a description of the currently available video sinks.
-
-@section buffersink
-
-Buffer video frames, and make them available to the end of the filter
-graph.
-
-This sink is intended for a programmatic use through the interface defined in
-@file{libavfilter/buffersink.h}.
-
-@section 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.
-
-@c man end VIDEO SINKS
+@c man end MULTIMEDIA SOURCES
projects / ffmpeg / blobdiff