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@chapter Filtergraph description
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@c man begin FILTERGRAPH DESCRIPTION
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A filtergraph is a directed graph of connected filters. It can contain
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cycles, and there can be multiple links between a pair of
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filters. Each link has one input pad on one side connecting it to one
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filter from which it takes its input, and one output pad on the other
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side connecting it to the one filter accepting its output.
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Each filter in a filtergraph is an instance of a filter class
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registered in the application, which defines the features and the
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number of input and output pads of the filter.
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A filter with no input pads is called a "source", a filter with no
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output pads is called a "sink".
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@section Filtergraph syntax
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A filtergraph can be represented using a textual representation, which
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is recognized by the @code{-vf} and @code{-af} options of the ff*
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tools, and by the @code{av_parse_graph()} function defined in
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@file{libavfilter/avfiltergraph}.
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A filterchain consists of a sequence of connected filters, each one
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connected to the previous one in the sequence. A filterchain is
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represented by a list of ","-separated filter descriptions.
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A filtergraph consists of a sequence of filterchains. A sequence of
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filterchains is represented by a list of ";"-separated filterchain
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descriptions.
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A filter is represented by a string of the form:
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[@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
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@var{filter_name} is the name of the filter class of which the
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described filter is an instance of, and has to be the name of one of
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the filter classes registered in the program.
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The name of the filter class is optionally followed by a string
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"=@var{arguments}".
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@var{arguments} is a string which contains the parameters used to
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initialize the filter instance, and are described in the filter
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descriptions below.
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The list of arguments can be quoted using the character "'" as initial
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and ending mark, and the character '\' for escaping the characters
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within the quoted text; otherwise the argument string is considered
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terminated when the next special character (belonging to the set
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"[]=;,") is encountered.
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The name and arguments of the filter are optionally preceded and
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followed by a list of link labels.
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A link label allows to name a link and associate it to a filter output
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or input pad. The preceding labels @var{in_link_1}
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... @var{in_link_N}, are associated to the filter input pads,
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the following labels @var{out_link_1} ... @var{out_link_M}, are
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associated to the output pads.
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When two link labels with the same name are found in the
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filtergraph, a link between the corresponding input and output pad is
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created.
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If an output pad is not labelled, it is linked by default to the first
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unlabelled input pad of the next filter in the filterchain.
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For example in the filterchain:
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@example
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nullsrc, split[L1], [L2]overlay, nullsink
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@end example
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the split filter instance has two output pads, and the overlay filter
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instance two input pads. The first output pad of split is labelled
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"L1", the first input pad of overlay is labelled "L2", and the second
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output pad of split is linked to the second input pad of overlay,
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which are both unlabelled.
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In a complete filterchain all the unlabelled filter input and output
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pads must be connected. A filtergraph is considered valid if all the
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filter input and output pads of all the filterchains are connected.
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Follows a BNF description for the filtergraph syntax:
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@example
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@var{NAME}             ::= sequence of alphanumeric characters and '_'
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@var{LINKLABEL}        ::= "[" @var{NAME} "]"
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@var{LINKLABELS}       ::= @var{LINKLABEL} [@var{LINKLABELS}]
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@var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
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@var{FILTER}           ::= [@var{LINKNAMES}] @var{NAME} ["=" @var{ARGUMENTS}] [@var{LINKNAMES}]
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@var{FILTERCHAIN}      ::= @var{FILTER} [,@var{FILTERCHAIN}]
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@var{FILTERGRAPH}      ::= @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
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@end example
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@c man end FILTERGRAPH DESCRIPTION
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@chapter Audio Filters
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@c man begin AUDIO FILTERS
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When you configure your FFmpeg build, you can disable any of the
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existing filters using --disable-filters.
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The configure output will show the audio filters included in your
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build.
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Below is a description of the currently available audio filters.
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@section anull
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Pass the audio source unchanged to the output.
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@c man end AUDIO FILTERS
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@chapter Audio Sources
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@c man begin AUDIO SOURCES
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Below is a description of the currently available audio sources.
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@section anullsrc
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Null audio source, never return audio frames. It is mainly useful as a
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template and to be employed in analysis / debugging tools.
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It accepts as optional parameter a string of the form
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@var{sample_rate}:@var{channel_layout}.
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@var{sample_rate} specify the sample rate, and defaults to 44100.
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@var{channel_layout} specify the channel layout, and can be either an
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integer or a string representing a channel layout. The default value
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of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
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Check the channel_layout_map definition in
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@file{libavcodec/audioconvert.c} for the mapping between strings and
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channel layout values.
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Follow some examples:
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@example
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#  set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
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anullsrc=48000:4
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# same as
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anullsrc=48000:mono
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@end example
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@c man end AUDIO SOURCES
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@chapter Audio Sinks
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@c man begin AUDIO SINKS
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Below is a description of the currently available audio sinks.
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@section anullsink
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Null audio sink, do absolutely nothing with the input audio. It is
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mainly useful as a template and to be employed in analysis / debugging
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tools.
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@c man end AUDIO SINKS
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@chapter Video Filters
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@c man begin VIDEO FILTERS
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When you configure your FFmpeg build, you can disable any of the
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existing filters using --disable-filters.
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The configure output will show the video filters included in your
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build.
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Below is a description of the currently available video filters.
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@section blackframe
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Detect frames that are (almost) completely black. Can be useful to
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detect chapter transitions or commercials. Output lines consist of
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the frame number of the detected frame, the percentage of blackness,
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the position in the file if known or -1 and the timestamp in seconds.
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In order to display the output lines, you need to set the loglevel at
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least to the AV_LOG_INFO value.
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The filter accepts the syntax:
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@example
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blackframe[=@var{amount}:[@var{threshold}]]
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@end example
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@var{amount} is the percentage of the pixels that have to be below the
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threshold, and defaults to 98.
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@var{threshold} is the threshold below which a pixel value is
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considered black, and defaults to 32.
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@section copy
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Copy the input source unchanged to the output. Mainly useful for
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testing purposes.
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@section crop
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Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
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The parameters are expressions containing the following constants:
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@table @option
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@item E, PI, PHI
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the corresponding mathematical approximated values for e
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(euler number), pi (greek PI), PHI (golden ratio)
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@item x, y
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the computed values for @var{x} and @var{y}. They are evaluated for
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each new frame.
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@item in_w, in_h
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the input width and heigth
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@item iw, ih
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same as @var{in_w} and @var{in_h}
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@item out_w, out_h
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the output (cropped) width and heigth
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@item ow, oh
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same as @var{out_w} and @var{out_h}
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@item n
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the number of input frame, starting from 0
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@item pos
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the position in the file of the input frame, NAN if unknown
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@item t
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timestamp expressed in seconds, NAN if the input timestamp is unknown
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@end table
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The @var{out_w} and @var{out_h} parameters specify the expressions for
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the width and height of the output (cropped) video. They are
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evaluated just at the configuration of the filter.
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The default value of @var{out_w} is "in_w", and the default value of
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@var{out_h} is "in_h".
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The expression for @var{out_w} may depend on the value of @var{out_h},
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and the expression for @var{out_h} may depend on @var{out_w}, but they
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cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
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evaluated after @var{out_w} and @var{out_h}.
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The @var{x} and @var{y} parameters specify the expressions for the
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position of the top-left corner of the output (non-cropped) area. They
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are evaluated for each frame. If the evaluated value is not valid, it
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is approximated to the nearest valid value.
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The default value of @var{x} is "(in_w-out_w)/2", and the default
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value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
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the center of the input image.
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The expression for @var{x} may depend on @var{y}, and the expression
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for @var{y} may depend on @var{x}.
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Follow some examples:
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@example
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# crop the central input area with size 100x100
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crop=100:100
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# crop the central input area with size 2/3 of the input video
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"crop=2/3*in_w:2/3*in_h"
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# crop the input video central square
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crop=in_h
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# delimit the rectangle with the top-left corner placed at position
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# 100:100 and the right-bottom corner corresponding to the right-bottom
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# corner of the input image.
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crop=in_w-100:in_h-100:100:100
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# crop 10 pixels from the left and right borders, and 20 pixels from
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# the top and bottom borders
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"crop=in_w-2*10:in_h-2*20"
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# keep only the bottom right quarter of the input image
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"crop=in_w/2:in_h/2:in_w/2:in_h/2"
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# crop height for getting Greek harmony
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"crop=in_w:1/PHI*in_w"
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# trembling effect
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"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)"
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# erratic camera effect depending on timestamp
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"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)"
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# set x depending on the value of y
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"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
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@end example
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@section cropdetect
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Auto-detect crop size.
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Calculate necessary cropping parameters and prints the recommended
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parameters through the logging system. The detected dimensions
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correspond to the non-black area of the input video.
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It accepts the syntax:
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@example
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cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
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@end example
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@table @option
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@item limit
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Threshold, which can be optionally specified from nothing (0) to
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everything (255), defaults to 24.
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@item round
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Value which the width/height should be divisible by, defaults to
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16. The offset is automatically adjusted to center the video. Use 2 to
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get only even dimensions (needed for 4:2:2 video). 16 is best when
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encoding to most video codecs.
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@item reset
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Counter that determines after how many frames cropdetect will reset
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the previously detected largest video area and start over to detect
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the current optimal crop area. Defaults to 0.
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This can be useful when channel logos distort the video area. 0
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indicates never reset and return the largest area encountered during
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playback.
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@end table
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@section drawbox
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Draw a colored box on the input image.
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It accepts the syntax:
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@example
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drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
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@end example
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@table @option
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@item x, y
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Specify the top left corner coordinates of the box. Default to 0.
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@item width, height
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Specify the width and height of the box, if 0 they are interpreted as
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the input width and height. Default to 0.
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@item color
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Specify the color of the box to write, it can be the name of a color
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(case insensitive match) or a 0xRRGGBB[AA] sequence.
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@end table
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Follow some examples:
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@example
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# draw a black box around the edge of the input image
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drawbox
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# draw a box with color red and an opacity of 50%
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drawbox=10:20:200:60:red@@0.5"
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@end example
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@section fifo
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Buffer input images and send them when they are requested.
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This filter is mainly useful when auto-inserted by the libavfilter
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framework.
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The filter does not take parameters.
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@section format
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Convert the input video to one of the specified pixel formats.
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Libavfilter will try to pick one that is supported for the input to
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the next filter.
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The filter accepts a list of pixel format names, separated by ":",
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for example "yuv420p:monow:rgb24".
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Some examples follow:
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@example
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# convert the input video to the format "yuv420p"
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format=yuv420p
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# convert the input video to any of the formats in the list
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format=yuv420p:yuv444p:yuv410p
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@end example
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@anchor{frei0r}
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@section frei0r
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Apply a frei0r effect to the input video.
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To enable compilation of this filter you need to install the frei0r
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header and configure FFmpeg with --enable-frei0r.
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The filter supports the syntax:
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@example
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@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
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@end example
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@var{filter_name} is the name to the frei0r effect to load. If the
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environment variable @env{FREI0R_PATH} is defined, the frei0r effect
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is searched in each one of the directories specified by the colon
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separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
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paths, which are in this order: @file{HOME/.frei0r-1/lib/},
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@file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
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@var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
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for the frei0r effect.
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A frei0r effect parameter can be a boolean (whose values are specified
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with "y" and "n"), a double, a color (specified by the syntax
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@var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
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numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
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description), a position (specified by the syntax @var{X}/@var{Y},
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@var{X} and @var{Y} being float numbers) and a string.
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The number and kind of parameters depend on the loaded effect. If an
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effect parameter is not specified the default value is set.
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Some examples follow:
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@example
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# apply the distort0r effect, set the first two double parameters
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frei0r=distort0r:0.5:0.01
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# apply the colordistance effect, takes a color as first parameter
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frei0r=colordistance:0.2/0.3/0.4
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frei0r=colordistance:violet
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frei0r=colordistance:0x112233
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# apply the perspective effect, specify the top left and top right
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# image positions
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frei0r=perspective:0.2/0.2:0.8/0.2
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@end example
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For more information see:
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@url{http://piksel.org/frei0r}
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@section gradfun
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Fix the banding artifacts that are sometimes introduced into nearly flat
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regions by truncation to 8bit colordepth.
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Interpolate the gradients that should go where the bands are, and
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dither them.
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The filter takes two optional parameters, separated by ':':
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@var{strength}:@var{radius}
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@var{strength} is the maximum amount by which the filter will change
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any one pixel. Also the threshold for detecting nearly flat
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regions. Acceptable values range from .51 to 255, default value is
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1.2, out-of-range values will be clipped to the valid range.
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@var{radius} is the neighborhood to fit the gradient to. A larger
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radius makes for smoother gradients, but also prevents the filter from
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modifying the pixels near detailed regions. Acceptable values are
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8-32, default value is 16, out-of-range values will be clipped to the
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valid range.
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@example
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# default parameters
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gradfun=1.2:16
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# omitting radius
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gradfun=1.2
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@end example
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@section hflip
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Flip the input video horizontally.
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For example to horizontally flip the video in input with
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@file{ffmpeg}:
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@example
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ffmpeg -i in.avi -vf "hflip" out.avi
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@end example
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@section hqdn3d
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High precision/quality 3d denoise filter. This filter aims to reduce
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image noise producing smooth images and making still images really
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still. It should enhance compressibility.
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It accepts the following optional parameters:
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@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
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@table @option
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@item luma_spatial
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a non-negative float number which specifies spatial luma strength,
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defaults to 4.0
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@item chroma_spatial
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a non-negative float number which specifies spatial chroma strength,
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defaults to 3.0*@var{luma_spatial}/4.0
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@item luma_tmp
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a float number which specifies luma temporal strength, defaults to
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6.0*@var{luma_spatial}/4.0
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@item chroma_tmp
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a float number which specifies chroma temporal strength, defaults to
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@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
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@end table
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@section noformat
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Force libavfilter not to use any of the specified pixel formats for the
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input to the next filter.
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The filter accepts a list of pixel format names, separated by ":",
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for example "yuv420p:monow:rgb24".
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Some examples follow:
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@example
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# force libavfilter to use a format different from "yuv420p" for the
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# input to the vflip filter
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noformat=yuv420p,vflip
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# convert the input video to any of the formats not contained in the list
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noformat=yuv420p:yuv444p:yuv410p
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@end example
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@section null
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Pass the video source unchanged to the output.
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@section ocv
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Apply video transform using libopencv.
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To enable this filter install libopencv library and headers and
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configure FFmpeg with --enable-libopencv.
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The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
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@var{filter_name} is the name of the libopencv filter to apply.
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@var{filter_params} specifies the parameters to pass to the libopencv
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filter. If not specified the default values are assumed.
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Refer to the official libopencv documentation for more precise
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informations:
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@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
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Follows the list of supported libopencv filters.
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@anchor{dilate}
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@subsection dilate
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Dilate an image by using a specific structuring element.
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This filter corresponds to the libopencv function @code{cvDilate}.
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It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
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@var{struct_el} represents a structuring element, and has the syntax:
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@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
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@var{cols} and @var{rows} represent the number of colums and rows of
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the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
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point, and @var{shape} the shape for the structuring element, and
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can be one of the values "rect", "cross", "ellipse", "custom".
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If the value for @var{shape} is "custom", it must be followed by a
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string of the form "=@var{filename}". The file with name
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@var{filename} is assumed to represent a binary image, with each
561
printable character corresponding to a bright pixel. When a custom
562
@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
563
or columns and rows of the read file are assumed instead.
564
565
The default value for @var{struct_el} is "3x3+0x0/rect".
566
567
@var{nb_iterations} specifies the number of times the transform is
568
applied to the image, and defaults to 1.
569
570
Follow some example:
571
@example
572
# use the default values
573
ocv=dilate
574
575
# dilate using a structuring element with a 5x5 cross, iterate two times
576
ocv=dilate=5x5+2x2/cross:2
577
578
# read the shape from the file diamond.shape, iterate two times
579
# the file diamond.shape may contain a pattern of characters like this:
580
#   *
581
#  ***
582
# *****
583
#  ***
584
#   *
585
# the specified cols and rows are ignored (but not the anchor point coordinates)
586
ocv=0x0+2x2/custom=diamond.shape:2
587
@end example
588
589 17fc9493 Stefano Sabatini
@subsection erode
590
591
Erode an image by using a specific structuring element.
592
This filter corresponds to the libopencv function @code{cvErode}.
593
594
The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
595
with the same meaning and use of those of the dilate filter
596
(@pxref{dilate}).
597
598 cf69ad35 Stefano Sabatini
@subsection smooth
599
600
Smooth the input video.
601
602
The filter takes the following parameters:
603 6ebf0bfc Stefano Sabatini
@var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
604
605
@var{type} is the type of smooth filter to apply, and can be one of
606 58d94364 Stefano Sabatini
the following values: "blur", "blur_no_scale", "median", "gaussian",
607 6ebf0bfc Stefano Sabatini
"bilateral". The default value is "gaussian".
608
609
@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
610
parameters whose meanings depend on smooth type. @var{param1} and
611
@var{param2} accept integer positive values or 0, @var{param3} and
612
@var{param4} accept float values.
613
614
The default value for @var{param1} is 3, the default value for the
615
other parameters is 0.
616
617 58d94364 Stefano Sabatini
These parameters correspond to the parameters assigned to the
618 cf69ad35 Stefano Sabatini
libopencv function @code{cvSmooth}.
619 6ebf0bfc Stefano Sabatini
620 58935b25 Stefano Sabatini
@section overlay
621
622
Overlay one video on top of another.
623
624
It takes two inputs and one output, the first input is the "main"
625
video on which the second input is overlayed.
626
627
It accepts the parameters: @var{x}:@var{y}.
628
629
@var{x} is the x coordinate of the overlayed video on the main video,
630
@var{y} is the y coordinate. The parameters are expressions containing
631
the following parameters:
632
633
@table @option
634
@item main_w, main_h
635
main input width and height
636
637
@item W, H
638
same as @var{main_w} and @var{main_h}
639
640
@item overlay_w, overlay_h
641
overlay input width and height
642
643
@item w, h
644
same as @var{overlay_w} and @var{overlay_h}
645
@end table
646
647
Be aware that frames are taken from each input video in timestamp
648
order, hence, if their initial timestamps differ, it is a a good idea
649
to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
650
have them begin in the same zero timestamp, as it does the example for
651
the @var{movie} filter.
652
653
Follow some examples:
654
@example
655
# draw the overlay at 10 pixels from the bottom right
656
# corner of the main video.
657
overlay=main_w-overlay_w-10:main_h-overlay_h-10
658
659
# insert a transparent PNG logo in the bottom left corner of the input
660
movie=0:png:logo.png [logo];
661
[in][logo] overlay=10:main_h-overlay_h-10 [out]
662
663
# insert 2 different transparent PNG logos (second logo on bottom
664
# right corner):
665
movie=0:png:logo1.png [logo1];
666
movie=0:png:logo2.png [logo2];
667
[in][logo1]       overlay=10:H-h-10 [in+logo1];
668
[in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
669
670
# add a transparent color layer on top of the main video,
671
# WxH specifies the size of the main input to the overlay filter
672
color=red@.3:WxH [over]; [in][over] overlay [out]
673
@end example
674
675
You can chain togheter more overlays but the efficiency of such
676
approach is yet to be tested.
677
678 3275ac6a Stefano Sabatini
@section pad
679
680
Add paddings to the input image, and places the original input at the
681
given coordinates @var{x}, @var{y}.
682
683
It accepts the following parameters:
684
@var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
685
686
Follows the description of the accepted parameters.
687
688
@table @option
689
@item width, height
690
691
Specify the size of the output image with the paddings added. If the
692
value for @var{width} or @var{height} is 0, the corresponding input size
693
is used for the output.
694
695
The default value of @var{width} and @var{height} is 0.
696
697
@item x, y
698
699
Specify the offsets where to place the input image in the padded area
700
with respect to the top/left border of the output image.
701
702
The default value of @var{x} and @var{y} is 0.
703
704
@item color
705
706
Specify the color of the padded area, it can be the name of a color
707
(case insensitive match) or a 0xRRGGBB[AA] sequence.
708
709 b1094275 Stefano Sabatini
The default value of @var{color} is "black".
710 3275ac6a Stefano Sabatini
711
@end table
712
713 3d17f4b9 Stefano Sabatini
For example:
714
715
@example
716
# Add paddings with color "violet" to the input video. Output video
717
# size is 640x480, the top-left corner of the input video is placed at
718
# row 0, column 40.
719
pad=640:480:0:40:violet
720
@end example
721
722 ce2e4ae3 Stefano Sabatini
@section pixdesctest
723
724
Pixel format descriptor test filter, mainly useful for internal
725
testing. The output video should be equal to the input video.
726
727
For example:
728
@example
729
format=monow, pixdesctest
730
@end example
731
732
can be used to test the monowhite pixel format descriptor definition.
733
734 3275ac6a Stefano Sabatini
@section scale
735
736
Scale the input video to @var{width}:@var{height} and/or convert the image format.
737
738
For example the command:
739
740
@example
741
./ffmpeg -i in.avi -vf "scale=200:100" out.avi
742
@end example
743
744
will scale the input video to a size of 200x100.
745
746
If the input image format is different from the format requested by
747
the next filter, the scale filter will convert the input to the
748
requested format.
749
750
If the value for @var{width} or @var{height} is 0, the respective input
751
size is used for the output.
752
753
If the value for @var{width} or @var{height} is -1, the scale filter will
754
use, for the respective output size, a value that maintains the aspect
755
ratio of the input image.
756
757
The default value of @var{width} and @var{height} is 0.
758
759 a532bb39 Stefano Sabatini
@section setpts
760
761
Change the PTS (presentation timestamp) of the input video frames.
762
763
Accept in input an expression evaluated through the eval API, which
764
can contain the following constants:
765
766
@table @option
767
@item PTS
768
the presentation timestamp in input
769
770
@item PI
771
Greek PI
772
773
@item PHI
774
golden ratio
775
776
@item E
777
Euler number
778
779
@item N
780
the count of the input frame, starting from 0.
781
782
@item STARTPTS
783
the PTS of the first video frame
784
785
@item INTERLACED
786
tell if the current frame is interlaced
787
788
@item POS
789
original position in the file of the frame, or undefined if undefined
790
for the current frame
791
792
@item PREV_INPTS
793
previous input PTS
794
795
@item PREV_OUTPTS
796
previous output PTS
797
798
@end table
799
800
Some examples follow:
801
802
@example
803
# start counting PTS from zero
804
setpts=PTS-STARTPTS
805
806
# fast motion
807
setpts=0.5*PTS
808
809
# slow motion
810
setpts=2.0*PTS
811
812
# fixed rate 25 fps
813
setpts=N/(25*TB)
814
815
# fixed rate 25 fps with some jitter
816
setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
817
@end example
818
819 d89e3b36 Stefano Sabatini
@section settb
820
821
Set the timebase to use for the output frames timestamps.
822
It is mainly useful for testing timebase configuration.
823
824
It accepts in input an arithmetic expression representing a rational.
825
The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
826
default timebase), and "intb" (the input timebase).
827
828
The default value for the input is "intb".
829
830
Follow some examples.
831
832
@example
833
# set the timebase to 1/25
834
settb=1/25
835
836
# set the timebase to 1/10
837
settb=0.1
838
839
#set the timebase to 1001/1000
840
settb=1+0.001
841
842
#set the timebase to 2*intb
843
settb=2*intb
844
845
#set the default timebase value
846
settb=AVTB
847
@end example
848
849 3275ac6a Stefano Sabatini
@section slicify
850
851
Pass the images of input video on to next video filter as multiple
852
slices.
853
854
@example
855
./ffmpeg -i in.avi -vf "slicify=32" out.avi
856
@end example
857
858
The filter accepts the slice height as parameter. If the parameter is
859
not specified it will use the default value of 16.
860
861
Adding this in the beginning of filter chains should make filtering
862
faster due to better use of the memory cache.
863
864 43945b27 Stefano Sabatini
@section transpose
865
866
Transpose rows with columns in the input video and optionally flip it.
867
868
It accepts a parameter representing an integer, which can assume the
869
values:
870
871
@table @samp
872
@item 0
873
Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
874
@example
875
L.R     L.l
876
. . ->  . .
877
l.r     R.r
878
@end example
879
880
@item 1
881
Rotate by 90 degrees clockwise, that is:
882
@example
883
L.R     l.L
884
. . ->  . .
885
l.r     r.R
886
@end example
887
888
@item 2
889
Rotate by 90 degrees counterclockwise, that is:
890
@example
891
L.R     R.r
892
. . ->  . .
893
l.r     L.l
894
@end example
895
896
@item 3
897
Rotate by 90 degrees clockwise and vertically flip, that is:
898
@example
899
L.R     r.R
900
. . ->  . .
901
l.r     l.L
902
@end example
903
@end table
904
905 3275ac6a Stefano Sabatini
@section unsharp
906
907 843b5fd0 Stefano Sabatini
Sharpen or blur the input video.
908
909
It accepts the following parameters:
910
@var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
911 3275ac6a Stefano Sabatini
912
Negative values for the amount will blur the input video, while positive
913
values will sharpen. All parameters are optional and default to the
914
equivalent of the string '5:5:1.0:0:0:0.0'.
915
916
@table @option
917
918
@item luma_msize_x
919
Set the luma matrix horizontal size. It can be an integer between 3
920
and 13, default value is 5.
921
922
@item luma_msize_y
923
Set the luma matrix vertical size. It can be an integer between 3
924
and 13, default value is 5.
925
926
@item luma_amount
927
Set the luma effect strength. It can be a float number between -2.0
928
and 5.0, default value is 1.0.
929
930
@item chroma_msize_x
931
Set the chroma matrix horizontal size. It can be an integer between 3
932
and 13, default value is 0.
933
934
@item chroma_msize_y
935
Set the chroma matrix vertical size. It can be an integer between 3
936
and 13, default value is 0.
937
938
@item luma_amount
939
Set the chroma effect strength. It can be a float number between -2.0
940
and 5.0, default value is 0.0.
941
942
@end table
943
944
@example
945
# Strong luma sharpen effect parameters
946
unsharp=7:7:2.5
947
948
# Strong blur of both luma and chroma parameters
949
unsharp=7:7:-2:7:7:-2
950
951
# Use the default values with @command{ffmpeg}
952
./ffmpeg -i in.avi -vf "unsharp" out.mp4
953
@end example
954
955
@section vflip
956
957
Flip the input video vertically.
958
959
@example
960
./ffmpeg -i in.avi -vf "vflip" out.avi
961
@end example
962
963 acbac567 Michael Niedermayer
@section yadif
964
965 1653027a Stefano Sabatini
Deinterlace the input video ("yadif" means "yet another deinterlacing
966
filter").
967 acbac567 Michael Niedermayer
968 1653027a Stefano Sabatini
It accepts the optional parameters: @var{mode}:@var{parity}.
969 acbac567 Michael Niedermayer
970 1653027a Stefano Sabatini
@var{mode} specifies the interlacing mode to adopt, accepts one of the
971
following values:
972 acbac567 Michael Niedermayer
973 1653027a Stefano Sabatini
@table @option
974
@item 0
975
output 1 frame for each frame
976
@item 1
977
output 1 frame for each field
978
@item 2
979
like 0 but skips spatial interlacing check
980
@item 3
981
like 1 but skips spatial interlacing check
982
@end table
983 acbac567 Michael Niedermayer
984
Default value is 0.
985
986 1653027a Stefano Sabatini
@var{parity} specifies the picture field parity assumed for the input
987
interlaced video, accepts one of the following values:
988 acbac567 Michael Niedermayer
989 1653027a Stefano Sabatini
@table @option
990
@item 0
991
assume bottom field first
992
@item 1
993
assume top field first
994
@item -1
995
enable automatic detection
996 acbac567 Michael Niedermayer
@end table
997
998 1653027a Stefano Sabatini
Default value is -1.
999 a51c71bb Baptiste Coudurier
If interlacing is unknown or decoder does not export this information,
1000
top field first will be assumed.
1001 1653027a Stefano Sabatini
1002 3275ac6a Stefano Sabatini
@c man end VIDEO FILTERS
1003
1004
@chapter Video Sources
1005
@c man begin VIDEO SOURCES
1006
1007
Below is a description of the currently available video sources.
1008
1009 24413399 Stefano Sabatini
@section buffer
1010
1011
Buffer video frames, and make them available to the filter chain.
1012
1013
This source is mainly intended for a programmatic use, in particular
1014 ac1a31ab VĂ­ctor Paesa
through the interface defined in @file{libavfilter/vsrc_buffer.h}.
1015 24413399 Stefano Sabatini
1016
It accepts the following parameters:
1017 7b3ea550 Michael Niedermayer
@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
1018 24413399 Stefano Sabatini
1019
All the parameters need to be explicitely defined.
1020
1021
Follows the list of the accepted parameters.
1022
1023
@table @option
1024
1025
@item width, height
1026
Specify the width and height of the buffered video frames.
1027
1028
@item pix_fmt_string
1029
A string representing the pixel format of the buffered video frames.
1030
It may be a number corresponding to a pixel format, or a pixel format
1031
name.
1032
1033 94498ec9 Stefano Sabatini
@item timebase_num, timebase_den
1034
Specify numerator and denomitor of the timebase assumed by the
1035
timestamps of the buffered frames.
1036 7b3ea550 Michael Niedermayer
1037
@item sample_aspect_ratio.num, sample_aspect_ratio.den
1038
Specify numerator and denominator of the sample aspect ratio assumed
1039
by the video frames.
1040 24413399 Stefano Sabatini
@end table
1041
1042
For example:
1043
@example
1044 7b3ea550 Michael Niedermayer
buffer=320:240:yuv410p:1:24:1:1
1045 24413399 Stefano Sabatini
@end example
1046
1047
will instruct the source to accept video frames with size 320x240 and
1048 7b3ea550 Michael Niedermayer
with format "yuv410p", assuming 1/24 as the timestamps timebase and
1049
square pixels (1:1 sample aspect ratio).
1050 94498ec9 Stefano Sabatini
Since the pixel format with name "yuv410p" corresponds to the number 6
1051
(check the enum PixelFormat definition in @file{libavutil/pixfmt.h}),
1052
this example corresponds to:
1053 24413399 Stefano Sabatini
@example
1054 94498ec9 Stefano Sabatini
buffer=320:240:6:1:24
1055 24413399 Stefano Sabatini
@end example
1056
1057 23ccf3c7 Stefano Sabatini
@section color
1058
1059
Provide an uniformly colored input.
1060
1061
It accepts the following parameters:
1062 b5f47309 Stefano Sabatini
@var{color}:@var{frame_size}:@var{frame_rate}
1063 23ccf3c7 Stefano Sabatini
1064
Follows the description of the accepted parameters.
1065
1066
@table @option
1067
1068
@item color
1069
Specify the color of the source. It can be the name of a color (case
1070
insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
1071
alpha specifier. The default value is "black".
1072
1073
@item frame_size
1074
Specify the size of the sourced video, it may be a string of the form
1075
@var{width}x@var{heigth}, or the name of a size abbreviation. The
1076
default value is "320x240".
1077
1078
@item frame_rate
1079
Specify the frame rate of the sourced video, as the number of frames
1080
generated per second. It has to be a string in the format
1081
@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
1082
number or a valid video frame rate abbreviation. The default value is
1083
"25".
1084
1085
@end table
1086
1087
For example the following graph description will generate a red source
1088
with an opacity of 0.2, with size "qcif" and a frame rate of 10
1089
frames per second, which will be overlayed over the source connected
1090
to the pad with identifier "in".
1091
1092
@example
1093
"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
1094
@end example
1095
1096 3275ac6a Stefano Sabatini
@section nullsrc
1097
1098
Null video source, never return images. It is mainly useful as a
1099
template and to be employed in analysis / debugging tools.
1100
1101
It accepts as optional parameter a string of the form
1102 16134b7c Stefano Sabatini
@var{width}:@var{height}:@var{timebase}.
1103 3275ac6a Stefano Sabatini
1104 16134b7c Stefano Sabatini
@var{width} and @var{height} specify the size of the configured
1105
source. The default values of @var{width} and @var{height} are
1106
respectively 352 and 288 (corresponding to the CIF size format).
1107
1108
@var{timebase} specifies an arithmetic expression representing a
1109
timebase. The expression can contain the constants "PI", "E", "PHI",
1110
"AVTB" (the default timebase), and defaults to the value "AVTB".
1111 3275ac6a Stefano Sabatini
1112 f8608dca Stefano Sabatini
@section frei0r_src
1113
1114
Provide a frei0r source.
1115
1116
To enable compilation of this filter you need to install the frei0r
1117
header and configure FFmpeg with --enable-frei0r.
1118
1119
The source supports the syntax:
1120
@example
1121
@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
1122
@end example
1123
1124
@var{size} is the size of the video to generate, may be a string of the
1125
form @var{width}x@var{height} or a frame size abbreviation.
1126
@var{rate} is the rate of the video to generate, may be a string of
1127
the form @var{num}/@var{den} or a frame rate abbreviation.
1128
@var{src_name} is the name to the frei0r source to load. For more
1129
information regarding frei0r and how to set the parameters read the
1130
section "frei0r" (@pxref{frei0r}) in the description of the video
1131
filters.
1132
1133
Some examples follow:
1134
@example
1135
# generate a frei0r partik0l source with size 200x200 and framerate 10
1136
# which is overlayed on the overlay filter main input
1137
frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
1138
@end example
1139
1140 3275ac6a Stefano Sabatini
@c man end VIDEO SOURCES
1141
1142
@chapter Video Sinks
1143
@c man begin VIDEO SINKS
1144
1145
Below is a description of the currently available video sinks.
1146
1147
@section nullsink
1148
1149
Null video sink, do absolutely nothing with the input video. It is
1150
mainly useful as a template and to be employed in analysis / debugging
1151
tools.
1152
1153
@c man end VIDEO SINKS