mirror of
https://git.ffmpeg.org/ffmpeg.git
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5c9ca599a7
0 is top-field-first, 1 is bottom-field-first, not the other way
around.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
(cherry picked from commit 4703a7b50b)
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Reinhard Tartler <siretart@tauware.de>
1575 lines
45 KiB
Plaintext
1575 lines
45 KiB
Plaintext
@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 Libav 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 Libav 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 drawtext
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Draw text string or text from specified file on top of video using the
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libfreetype library.
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To enable compilation of this filter you need to configure FFmpeg with
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@code{--enable-libfreetype}.
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The filter also recognizes strftime() sequences in the provided text
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and expands them accordingly. Check the documentation of strftime().
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The filter accepts parameters as a list of @var{key}=@var{value} pairs,
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separated by ":".
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The description of the accepted parameters follows.
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@table @option
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@item fontfile
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The font file to be used for drawing text. Path must be included.
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This parameter is mandatory.
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@item text
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The text string to be drawn. The text must be a sequence of UTF-8
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encoded characters.
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This parameter is mandatory if no file is specified with the parameter
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@var{textfile}.
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@item textfile
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A text file containing text to be drawn. The text must be a sequence
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of UTF-8 encoded characters.
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This parameter is mandatory if no text string is specified with the
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parameter @var{text}.
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If both text and textfile are specified, an error is thrown.
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@item x, y
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The offsets where text will be drawn within the video frame.
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Relative to the top/left border of the output image.
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The default value of @var{x} and @var{y} is 0.
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@item fontsize
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The font size to be used for drawing text.
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The default value of @var{fontsize} is 16.
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@item fontcolor
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The color to be used for drawing fonts.
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Either a string (e.g. "red") or in 0xRRGGBB[AA] format
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(e.g. "0xff000033"), possibly followed by an alpha specifier.
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The default value of @var{fontcolor} is "black".
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@item boxcolor
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The color to be used for drawing box around text.
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Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
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(e.g. "0xff00ff"), possibly followed by an alpha specifier.
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The default value of @var{boxcolor} is "white".
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@item box
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Used to draw a box around text using background color.
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Value should be either 1 (enable) or 0 (disable).
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The default value of @var{box} is 0.
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@item shadowx, shadowy
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The x and y offsets for the text shadow position with respect to the
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position of the text. They can be either positive or negative
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values. Default value for both is "0".
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@item shadowcolor
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The color to be used for drawing a shadow behind the drawn text. It
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can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
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form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
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The default value of @var{shadowcolor} is "black".
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@item ft_load_flags
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Flags to be used for loading the fonts.
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The flags map the corresponding flags supported by libfreetype, and are
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a combination of the following values:
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@table @var
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@item default
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@item no_scale
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@item no_hinting
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@item render
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@item no_bitmap
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@item vertical_layout
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@item force_autohint
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@item crop_bitmap
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@item pedantic
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@item ignore_global_advance_width
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@item no_recurse
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@item ignore_transform
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@item monochrome
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@item linear_design
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@item no_autohint
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@item end table
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@end table
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Default value is "render".
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For more information consult the documentation for the FT_LOAD_*
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libfreetype flags.
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@item tabsize
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The size in number of spaces to use for rendering the tab.
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Default value is 4.
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@end table
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For example the command:
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@example
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drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
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@end example
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will draw "Test Text" with font FreeSerif, using the default values
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for the optional parameters.
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The command:
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@example
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drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
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x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
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@end example
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will draw 'Test Text' with font FreeSerif of size 24 at position x=100
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and y=50 (counting from the top-left corner of the screen), text is
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yellow with a red box around it. Both the text and the box have an
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opacity of 20%.
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Note that the double quotes are not necessary if spaces are not used
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within the parameter list.
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For more information about libfreetype, check:
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@url{http://www.freetype.org/}.
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@section fade
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Apply fade-in/out effect to input video.
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It accepts the parameters:
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@var{type}:@var{start_frame}:@var{nb_frames}
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@var{type} specifies if the effect type, can be either "in" for
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fade-in, or "out" for a fade-out effect.
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@var{start_frame} specifies the number of the start frame for starting
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to apply the fade effect.
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@var{nb_frames} specifies the number of frames for which the fade
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effect has to last. At the end of the fade-in effect the output video
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will have the same intensity as the input video, at the end of the
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fade-out transition the output video will be completely black.
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A few usage examples follow, usable too as test scenarios.
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@example
|
|
# fade in first 30 frames of video
|
|
fade=in:0:30
|
|
|
|
# fade out last 45 frames of a 200-frame video
|
|
fade=out:155:45
|
|
|
|
# fade in first 25 frames and fade out last 25 frames of a 1000-frame video
|
|
fade=in:0:25, fade=out:975:25
|
|
|
|
# make first 5 frames black, then fade in from frame 5-24
|
|
fade=in:5:20
|
|
@end example
|
|
|
|
@section fieldorder
|
|
|
|
Transform the field order of the input video.
|
|
|
|
It accepts one parameter which specifies the required field order that
|
|
the input interlaced video will be transformed to. The parameter can
|
|
assume one of the following values:
|
|
|
|
@table @option
|
|
@item 0 or bff
|
|
output bottom field first
|
|
@item 1 or tff
|
|
output top field first
|
|
@end table
|
|
|
|
Default value is "tff".
|
|
|
|
Transformation is achieved by shifting the picture content up or down
|
|
by one line, and filling the remaining line with appropriate picture content.
|
|
This method is consistent with most broadcast field order converters.
|
|
|
|
If the input video is not flagged as being interlaced, or it is already
|
|
flagged as being of the required output field order then this filter does
|
|
not alter the incoming video.
|
|
|
|
This filter is very useful when converting to or from PAL DV material,
|
|
which is bottom field first.
|
|
|
|
For example:
|
|
@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.
|
|
|
|
@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.
|
|
|
|
The filter accepts a list of pixel format names, separated by ":",
|
|
for example "yuv420p:monow:rgb24".
|
|
|
|
Some examples follow:
|
|
@example
|
|
# convert the input video to the format "yuv420p"
|
|
format=yuv420p
|
|
|
|
# convert the input video to any of the formats in the list
|
|
format=yuv420p:yuv444p:yuv410p
|
|
@end example
|
|
|
|
@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 Libav with --enable-frei0r.
|
|
|
|
The filter supports the syntax:
|
|
@example
|
|
@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
|
|
@end example
|
|
|
|
@var{filter_name} is 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/}.
|
|
|
|
@var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
|
|
for the frei0r effect.
|
|
|
|
A frei0r effect parameter can be a boolean (whose values are specified
|
|
with "y" and "n"), a double, a color (specified by the syntax
|
|
@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.
|
|
|
|
The number and kind of parameters depend on the loaded effect. If an
|
|
effect parameter is not specified the default value is set.
|
|
|
|
Some examples follow:
|
|
@example
|
|
# apply the distort0r effect, set the first two double parameters
|
|
frei0r=distort0r:0.5:0.01
|
|
|
|
# apply the colordistance effect, takes a color as first parameter
|
|
frei0r=colordistance:0.2/0.3/0.4
|
|
frei0r=colordistance:violet
|
|
frei0r=colordistance:0x112233
|
|
|
|
# apply the perspective effect, specify the top left and top right
|
|
# image positions
|
|
frei0r=perspective:0.2/0.2:0.8/0.2
|
|
@end example
|
|
|
|
For more information see:
|
|
@url{http://piksel.org/frei0r}
|
|
|
|
@section gradfun
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
The filter takes two optional parameters, separated by ':':
|
|
@var{strength}:@var{radius}
|
|
|
|
@var{strength} is 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 255, default value is
|
|
1.2, out-of-range values will be clipped to the valid range.
|
|
|
|
@var{radius} is 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.
|
|
|
|
@example
|
|
# default parameters
|
|
gradfun=1.2:16
|
|
|
|
# omitting radius
|
|
gradfun=1.2
|
|
@end example
|
|
|
|
@section hflip
|
|
|
|
Flip the input video horizontally.
|
|
|
|
For example to horizontally flip the video in input with
|
|
@file{ffmpeg}:
|
|
@example
|
|
ffmpeg -i in.avi -vf "hflip" out.avi
|
|
@end example
|
|
|
|
@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:
|
|
@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
|
|
|
|
@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 noformat
|
|
|
|
Force libavfilter not to use any of the specified pixel formats for the
|
|
input to the next filter.
|
|
|
|
The filter accepts a list of pixel format names, separated by ":",
|
|
for example "yuv420p:monow:rgb24".
|
|
|
|
Some examples follow:
|
|
@example
|
|
# force libavfilter to use a format different from "yuv420p" for the
|
|
# input to the vflip filter
|
|
noformat=yuv420p,vflip
|
|
|
|
# convert the input video to any of the formats not contained in the list
|
|
noformat=yuv420p:yuv444p:yuv410p
|
|
@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 Libav with --enable-libopencv.
|
|
|
|
The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
|
|
|
|
@var{filter_name} is the name of the libopencv filter to apply.
|
|
|
|
@var{filter_params} specifies the parameters to pass to the libopencv
|
|
filter. If not specified the default values are assumed.
|
|
|
|
Refer to the official libopencv documentation for more precise
|
|
informations:
|
|
@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 colums 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=dilate=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=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 meaning and use of those of the dilate filter
|
|
(@pxref{dilate}).
|
|
|
|
@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}.
|
|
|
|
@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.
|
|
|
|
It accepts the parameters: @var{x}:@var{y}.
|
|
|
|
@var{x} is the x coordinate of the overlayed video on the main video,
|
|
@var{y} is the y coordinate. The parameters are expressions containing
|
|
the following parameters:
|
|
|
|
@table @option
|
|
@item main_w, main_h
|
|
main input width and height
|
|
|
|
@item W, H
|
|
same as @var{main_w} and @var{main_h}
|
|
|
|
@item overlay_w, overlay_h
|
|
overlay input width and height
|
|
|
|
@item w, h
|
|
same as @var{overlay_w} and @var{overlay_h}
|
|
@end table
|
|
|
|
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.
|
|
|
|
Follow some examples:
|
|
@example
|
|
# draw the overlay at 10 pixels from the bottom right
|
|
# corner of the main video.
|
|
overlay=main_w-overlay_w-10:main_h-overlay_h-10
|
|
|
|
# insert a transparent PNG logo in the bottom left corner of the input
|
|
movie=logo.png [logo];
|
|
[in][logo] overlay=10:main_h-overlay_h-10 [out]
|
|
|
|
# insert 2 different transparent PNG logos (second logo on bottom
|
|
# right corner):
|
|
movie=logo1.png [logo1];
|
|
movie=logo2.png [logo2];
|
|
[in][logo1] overlay=10:H-h-10 [in+logo1];
|
|
[in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
|
|
|
|
# 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]
|
|
@end example
|
|
|
|
You can chain togheter more overlays but the efficiency of such
|
|
approach is yet to be tested.
|
|
|
|
@section pad
|
|
|
|
Add paddings to the input image, and places the original input at the
|
|
given coordinates @var{x}, @var{y}.
|
|
|
|
It accepts the following parameters:
|
|
@var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
|
|
|
|
The parameters @var{width}, @var{height}, @var{x}, and @var{y} are
|
|
expressions 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 in_w, in_h
|
|
the input video width and heigth
|
|
|
|
@item iw, ih
|
|
same as @var{in_w} and @var{in_h}
|
|
|
|
@item out_w, out_h
|
|
the output width and heigth, that is the size of the padded area as
|
|
specified by the @var{width} and @var{height} expressions
|
|
|
|
@item ow, oh
|
|
same as @var{out_w} and @var{out_h}
|
|
|
|
@item x, y
|
|
x and y offsets as specified by the @var{x} and @var{y}
|
|
expressions, or NAN if not yet specified
|
|
|
|
@item a
|
|
input display aspect ratio, same as @var{iw} / @var{ih}
|
|
|
|
@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
|
|
|
|
Follows the description of the accepted parameters.
|
|
|
|
@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 viceversa.
|
|
|
|
The default value of @var{width} and @var{height} is 0.
|
|
|
|
@item x, y
|
|
|
|
Specify 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 viceversa.
|
|
|
|
The default value of @var{x} and @var{y} is 0.
|
|
|
|
@item color
|
|
|
|
Specify the color of the padded area, it can be the name of a color
|
|
(case insensitive match) or a 0xRRGGBB[AA] sequence.
|
|
|
|
The default value of @var{color} is "black".
|
|
|
|
@end table
|
|
|
|
Some examples follow:
|
|
|
|
@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=640:480:0:40:violet
|
|
|
|
# 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"
|
|
|
|
# pad the input to get a squared output with size equal to the maximum
|
|
# value between the input width and height, and put the input video at
|
|
# the center of the padded area
|
|
pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
|
|
|
|
# pad the input to get a final w/h ratio of 16:9
|
|
pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
|
|
|
|
# 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
|
|
|
|
@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 scale
|
|
|
|
Scale the input video to @var{width}:@var{height} and/or convert the image format.
|
|
|
|
The parameters @var{width} and @var{height} are expressions 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 in_w, in_h
|
|
the input width and heigth
|
|
|
|
@item iw, ih
|
|
same as @var{in_w} and @var{in_h}
|
|
|
|
@item out_w, out_h
|
|
the output (cropped) width and heigth
|
|
|
|
@item ow, oh
|
|
same as @var{out_w} and @var{out_h}
|
|
|
|
@item a
|
|
input display aspect ratio, same as @var{iw} / @var{ih}
|
|
|
|
@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
|
|
|
|
If the input image format is different from the format requested by
|
|
the next filter, the scale filter will convert the input to the
|
|
requested format.
|
|
|
|
If the value for @var{width} or @var{height} is 0, the respective input
|
|
size is used for the output.
|
|
|
|
If the value for @var{width} or @var{height} is -1, the scale filter will
|
|
use, for the respective output size, a value that maintains the aspect
|
|
ratio of the input image.
|
|
|
|
The default value of @var{width} and @var{height} is 0.
|
|
|
|
Some examples follow:
|
|
@example
|
|
# scale the input video to a size of 200x100.
|
|
scale=200:100
|
|
|
|
# scale the input to 2x
|
|
scale=2*iw:2*ih
|
|
# the above is the same as
|
|
scale=2*in_w:2*in_h
|
|
|
|
# scale the input to half size
|
|
scale=iw/2:ih/2
|
|
|
|
# increase the width, and set the height to the same size
|
|
scale=3/2*iw:ow
|
|
|
|
# seek for Greek harmony
|
|
scale=iw:1/PHI*iw
|
|
scale=ih*PHI:ih
|
|
|
|
# increase the height, and set the width to 3/2 of the height
|
|
scale=3/2*oh:3/5*ih
|
|
|
|
# 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"
|
|
|
|
# increase the width to a maximum of 500 pixels, keep the same input aspect ratio
|
|
scale='min(500\, iw*3/2):-1'
|
|
@end example
|
|
|
|
@anchor{setdar}
|
|
@section setdar
|
|
|
|
Set 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:
|
|
@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
|
|
|
|
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.
|
|
|
|
The filter accepts a parameter string which represents the wanted
|
|
display aspect ratio.
|
|
The parameter can be a floating point number string, or an expression
|
|
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 "0:1".
|
|
|
|
For example to change the display aspect ratio to 16:9, specify:
|
|
@example
|
|
setdar=16:9
|
|
# the above is equivalent to
|
|
setdar=1.77777
|
|
@end example
|
|
|
|
See also the "setsar" filter documentation (@pxref{setsar}).
|
|
|
|
@section setpts
|
|
|
|
Change the PTS (presentation timestamp) of the input video frames.
|
|
|
|
Accept in input an expression evaluated through the eval API, which
|
|
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 POS
|
|
original position in the file of the frame, or undefined if undefined
|
|
for the current frame
|
|
|
|
@item PREV_INPTS
|
|
previous input PTS
|
|
|
|
@item PREV_OUTPTS
|
|
previous output PTS
|
|
|
|
@end table
|
|
|
|
Some examples follow:
|
|
|
|
@example
|
|
# start counting PTS from zero
|
|
setpts=PTS-STARTPTS
|
|
|
|
# fast motion
|
|
setpts=0.5*PTS
|
|
|
|
# slow motion
|
|
setpts=2.0*PTS
|
|
|
|
# fixed rate 25 fps
|
|
setpts=N/(25*TB)
|
|
|
|
# fixed rate 25 fps with some jitter
|
|
setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
|
|
@end example
|
|
|
|
@anchor{setsar}
|
|
@section setsar
|
|
|
|
Set 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 following
|
|
equation:
|
|
@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
|
|
|
|
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.
|
|
|
|
The filter accepts a parameter string which represents the wanted
|
|
sample aspect ratio.
|
|
The parameter can be a floating point number string, or an expression
|
|
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 "0:1".
|
|
|
|
For example to change the sample aspect ratio to 10:11, specify:
|
|
@example
|
|
setsar=10:11
|
|
@end example
|
|
|
|
@section settb
|
|
|
|
Set the timebase to use for the output frames timestamps.
|
|
It is mainly useful for testing timebase configuration.
|
|
|
|
It accepts in input an arithmetic expression representing a rational.
|
|
The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
|
|
default timebase), and "intb" (the input timebase).
|
|
|
|
The default value for the input is "intb".
|
|
|
|
Follow some examples.
|
|
|
|
@example
|
|
# set the timebase to 1/25
|
|
settb=1/25
|
|
|
|
# set the timebase to 1/10
|
|
settb=0.1
|
|
|
|
#set the timebase to 1001/1000
|
|
settb=1+0.001
|
|
|
|
#set the timebase to 2*intb
|
|
settb=2*intb
|
|
|
|
#set the default timebase value
|
|
settb=AVTB
|
|
@end example
|
|
|
|
@section slicify
|
|
|
|
Pass the images of input video on to next video filter as multiple
|
|
slices.
|
|
|
|
@example
|
|
./ffmpeg -i in.avi -vf "slicify=32" out.avi
|
|
@end example
|
|
|
|
The filter accepts the slice height as parameter. If the parameter is
|
|
not specified it will use the default value of 16.
|
|
|
|
Adding this in the beginning of filter chains should make filtering
|
|
faster due to better use of the memory cache.
|
|
|
|
@section transpose
|
|
|
|
Transpose rows with columns in the input video and optionally flip it.
|
|
|
|
It accepts a parameter representing an integer, which can assume the
|
|
values:
|
|
|
|
@table @samp
|
|
@item 0
|
|
Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
|
|
@example
|
|
L.R L.l
|
|
. . -> . .
|
|
l.r R.r
|
|
@end example
|
|
|
|
@item 1
|
|
Rotate by 90 degrees clockwise, that is:
|
|
@example
|
|
L.R l.L
|
|
. . -> . .
|
|
l.r r.R
|
|
@end example
|
|
|
|
@item 2
|
|
Rotate by 90 degrees counterclockwise, that is:
|
|
@example
|
|
L.R R.r
|
|
. . -> . .
|
|
l.r L.l
|
|
@end example
|
|
|
|
@item 3
|
|
Rotate by 90 degrees clockwise and vertically flip, that is:
|
|
@example
|
|
L.R r.R
|
|
. . -> . .
|
|
l.r l.L
|
|
@end example
|
|
@end table
|
|
|
|
@section unsharp
|
|
|
|
Sharpen or blur the input video.
|
|
|
|
It accepts the following parameters:
|
|
@var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
|
|
|
|
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 '5:5:1.0:0:0:0.0'.
|
|
|
|
@table @option
|
|
|
|
@item luma_msize_x
|
|
Set the luma matrix horizontal size. It can be an integer between 3
|
|
and 13, default value is 5.
|
|
|
|
@item luma_msize_y
|
|
Set the luma matrix vertical size. It can be an integer between 3
|
|
and 13, default value is 5.
|
|
|
|
@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.
|
|
|
|
@item chroma_msize_x
|
|
Set the chroma matrix horizontal size. It can be an integer between 3
|
|
and 13, default value is 0.
|
|
|
|
@item chroma_msize_y
|
|
Set the chroma matrix vertical size. It can be an integer between 3
|
|
and 13, default value is 0.
|
|
|
|
@item luma_amount
|
|
Set the chroma effect strength. It can be a float number between -2.0
|
|
and 5.0, default value is 0.0.
|
|
|
|
@end table
|
|
|
|
@example
|
|
# Strong luma sharpen effect parameters
|
|
unsharp=7:7:2.5
|
|
|
|
# Strong blur of both luma and chroma parameters
|
|
unsharp=7:7:-2:7:7:-2
|
|
|
|
# Use the default values with @command{ffmpeg}
|
|
./ffmpeg -i in.avi -vf "unsharp" out.mp4
|
|
@end example
|
|
|
|
@section vflip
|
|
|
|
Flip the input video vertically.
|
|
|
|
@example
|
|
./ffmpeg -i in.avi -vf "vflip" out.avi
|
|
@end example
|
|
|
|
@section yadif
|
|
|
|
Deinterlace the input video ("yadif" means "yet another deinterlacing
|
|
filter").
|
|
|
|
It accepts the optional parameters: @var{mode}:@var{parity}.
|
|
|
|
@var{mode} specifies the interlacing mode to adopt, accepts one of the
|
|
following values:
|
|
|
|
@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
|
|
@end table
|
|
|
|
Default value is 0.
|
|
|
|
@var{parity} specifies the picture field parity assumed for the input
|
|
interlaced video, accepts one of the following values:
|
|
|
|
@table @option
|
|
@item 0
|
|
assume top field first
|
|
@item 1
|
|
assume bottom field first
|
|
@item -1
|
|
enable automatic detection
|
|
@end table
|
|
|
|
Default value is -1.
|
|
If interlacing is unknown or decoder does not export this information,
|
|
top field first will be assumed.
|
|
|
|
@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}.
|
|
|
|
It accepts the following parameters:
|
|
@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
|
|
|
|
All the parameters need to be explicitely defined.
|
|
|
|
Follows the list of the accepted parameters.
|
|
|
|
@table @option
|
|
|
|
@item width, height
|
|
Specify the width and height of the buffered video frames.
|
|
|
|
@item pix_fmt_string
|
|
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 timebase_num, timebase_den
|
|
Specify numerator and denomitor of the timebase assumed by the
|
|
timestamps of the buffered frames.
|
|
|
|
@item sample_aspect_ratio.num, sample_aspect_ratio.den
|
|
Specify numerator and denominator of the sample aspect ratio assumed
|
|
by the video frames.
|
|
@end table
|
|
|
|
For example:
|
|
@example
|
|
buffer=320:240:yuv410p:1:24:1:1
|
|
@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 PixelFormat definition in @file{libavutil/pixfmt.h}),
|
|
this example corresponds to:
|
|
@example
|
|
buffer=320:240:6:1:24
|
|
@end example
|
|
|
|
@section color
|
|
|
|
Provide an uniformly colored input.
|
|
|
|
It accepts the following parameters:
|
|
@var{color}:@var{frame_size}:@var{frame_rate}
|
|
|
|
Follows the description of the accepted parameters.
|
|
|
|
@table @option
|
|
|
|
@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".
|
|
|
|
@item frame_size
|
|
Specify the size of the sourced video, it may be a string of the form
|
|
@var{width}x@var{heigth}, or the name of a size abbreviation. The
|
|
default value is "320x240".
|
|
|
|
@item frame_rate
|
|
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".
|
|
|
|
@end table
|
|
|
|
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".
|
|
|
|
@example
|
|
"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
|
|
@end example
|
|
|
|
@section movie
|
|
|
|
Read a video stream from a movie container.
|
|
|
|
It accepts the syntax: @var{movie_name}[:@var{options}] where
|
|
@var{movie_name} is the name of the resource to read (not necessarily
|
|
a file but also a device or a stream accessed through some protocol),
|
|
and @var{options} is an optional sequence of @var{key}=@var{value}
|
|
pairs, separated by ":".
|
|
|
|
The description of the accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item format_name, f
|
|
Specifies the format assumed for the movie to read, and can be either
|
|
the name of a container or an input device. If not specified the
|
|
format is guessed from @var{movie_name} or by probing.
|
|
|
|
@item seek_point, sp
|
|
Specifies the seek point in seconds, the frames will be output
|
|
starting from this seek point, the parameter is evaluated with
|
|
@code{av_strtod} so the numerical value may be suffixed by an IS
|
|
postfix. Default value is "0".
|
|
|
|
@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".
|
|
|
|
@end table
|
|
|
|
This filter allows to overlay a second video on top of main input of
|
|
a filtergraph as shown in this graph:
|
|
@example
|
|
input -----------> deltapts0 --> overlay --> output
|
|
^
|
|
|
|
|
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.
|
|
|
|
The source supports the syntax:
|
|
@example
|
|
@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
|
|
@end example
|
|
|
|
@var{size} is the size of the video to generate, may be a string of the
|
|
form @var{width}x@var{height} or a frame size abbreviation.
|
|
@var{rate} is the rate of the video to generate, may be a string of
|
|
the form @var{num}/@var{den} or a frame rate abbreviation.
|
|
@var{src_name} is the name to the frei0r source to load. For more
|
|
information regarding frei0r and how to set the parameters read the
|
|
section "frei0r" (@pxref{frei0r}) in the description of the video
|
|
filters.
|
|
|
|
Some examples follow:
|
|
@example
|
|
# generate a frei0r partik0l source with size 200x200 and framerate 10
|
|
# which is overlayed on the overlay filter main input
|
|
frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
|
|
@end example
|
|
|
|
@c man end VIDEO SOURCES
|
|
|
|
@chapter Video Sinks
|
|
@c man begin VIDEO SINKS
|
|
|
|
Below is a description of the currently available video sinks.
|
|
|
|
@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
|
|
|