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5198 lines
147 KiB
Plaintext
5198 lines
147 KiB
Plaintext
@chapter Filtering Introduction
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@c man begin FILTERING INTRODUCTION
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Filtering in FFmpeg is enabled through the libavfilter library.
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Libavfilter is the filtering API of FFmpeg. It is the substitute of
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the now deprecated 'vhooks' and started as a Google Summer of Code
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project.
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Audio filtering integration into the main FFmpeg repository is a work in
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progress, so audio API and ABI should not be considered stable yet.
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In libavfilter, it is possible for filters to have multiple inputs and
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multiple outputs.
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To illustrate the sorts of things that are possible, we can
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use a complex filter graph. For example, the following one:
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@example
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input --> split --> fifo -----------------------> overlay --> output
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+------> fifo --> crop --> vflip --------+
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@end example
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splits the stream in two streams, sends one stream through the crop filter
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and the vflip filter before merging it back with the other stream by
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overlaying it on top. You can use the following command to achieve this:
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@example
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ffmpeg -i input -vf "[in] split [T1], fifo, [T2] overlay=0:H/2 [out]; [T1] fifo, crop=iw:ih/2:0:ih/2, vflip [T2]" output
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@end example
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The result will be that in output the top half of the video is mirrored
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onto the bottom half.
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Filters are loaded using the @var{-vf} or @var{-af} option passed to
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@command{ffmpeg} or to @command{ffplay}. Filters in the same linear
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chain are separated by commas. In our example, @var{split, fifo,
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overlay} are in one linear chain, and @var{fifo, crop, vflip} are in
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another. The points where the linear chains join are labeled by names
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enclosed in square brackets. In our example, that is @var{[T1]} and
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@var{[T2]}. The special labels @var{[in]} and @var{[out]} are the points
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where video is input and output.
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Some filters take in input a list of parameters: they are specified
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after the filter name and an equal sign, and are separated from each other
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by a colon.
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There exist so-called @var{source filters} that do not have an
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audio/video input, and @var{sink filters} that will not have audio/video
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output.
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@c man end FILTERING INTRODUCTION
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@chapter graph2dot
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@c man begin GRAPH2DOT
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The @file{graph2dot} program included in the FFmpeg @file{tools}
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directory can be used to parse a filter graph description and issue a
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corresponding textual representation in the dot language.
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Invoke the command:
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@example
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graph2dot -h
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@end example
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to see how to use @file{graph2dot}.
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You can then pass the dot description to the @file{dot} program (from
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the graphviz suite of programs) and obtain a graphical representation
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of the filter graph.
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For example the sequence of commands:
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@example
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echo @var{GRAPH_DESCRIPTION} | \
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tools/graph2dot -o graph.tmp && \
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dot -Tpng graph.tmp -o graph.png && \
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display graph.png
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@end example
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can be used to create and display an image representing the graph
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described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
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a complete self-contained graph, with its inputs and outputs explicitly defined.
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For example if your command line is of the form:
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@example
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ffmpeg -i infile -vf scale=640:360 outfile
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@end example
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your @var{GRAPH_DESCRIPTION} string will need to be of the form:
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@example
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nullsrc,scale=640:360,nullsink
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@end example
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you may also need to set the @var{nullsrc} parameters and add a @var{format}
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filter in order to simulate a specific input file.
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@c man end GRAPH2DOT
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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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@anchor{Filtergraph syntax}
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@section Filtergraph syntax
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A filtergraph can be represented using a textual representation, which is
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recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
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options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
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@code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
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@file{libavfilter/avfiltergraph.h}.
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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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Libavfilter will automatically insert scale filters where format
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conversion is required. It is possible to specify swscale flags
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for those automatically inserted scalers by prepending
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@code{sws_flags=@var{flags};}
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to the filtergraph description.
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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} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
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@end example
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@section Notes on filtergraph escaping
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Some filter arguments require the use of special characters, typically
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@code{:} to separate key=value pairs in a named options list. In this
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case the user should perform a first level escaping when specifying
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the filter arguments. For example, consider the following literal
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string to be embedded in the @ref{drawtext} filter arguments:
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@example
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this is a 'string': may contain one, or more, special characters
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@end example
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Since @code{:} is special for the filter arguments syntax, it needs to
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be escaped, so you get:
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@example
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text=this is a \'string\'\: may contain one, or more, special characters
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@end example
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A second level of escaping is required when embedding the filter
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arguments in a filtergraph description, in order to escape all the
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filtergraph special characters. Thus the example above becomes:
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@example
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drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
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@end example
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Finally an additional level of escaping may be needed when writing the
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filtergraph description in a shell command, which depends on the
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escaping rules of the adopted shell. For example, assuming that
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@code{\} is special and needs to be escaped with another @code{\}, the
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previous string will finally result in:
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@example
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-vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
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@end example
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Sometimes, it might be more convenient to employ quoting in place of
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escaping. For example the string:
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@example
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Caesar: tu quoque, Brute, fili mi
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@end example
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Can be quoted in the filter arguments as:
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@example
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text='Caesar: tu quoque, Brute, fili mi'
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@end example
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And finally inserted in a filtergraph like:
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@example
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drawtext=text=\'Caesar: tu quoque\, Brute\, fili mi\'
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@end example
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See the @ref{quoting_and_escaping, Quoting and escaping} section for
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more information about the escaping and quoting rules adopted by
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FFmpeg.
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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 @code{--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 aconvert
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Convert the input audio format to the specified formats.
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The filter accepts a string of the form:
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"@var{sample_format}:@var{channel_layout}".
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@var{sample_format} specifies the sample format, and can be a string or the
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corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
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suffix for a planar sample format.
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@var{channel_layout} specifies the channel layout, and can be a string
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or the corresponding number value defined in @file{libavutil/channel_layout.h}.
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The special parameter "auto", signifies that the filter will
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automatically select the output format depending on the output filter.
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Some examples follow.
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@itemize
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@item
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Convert input to float, planar, stereo:
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@example
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aconvert=fltp:stereo
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@end example
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@item
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Convert input to unsigned 8-bit, automatically select out channel layout:
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@example
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aconvert=u8:auto
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@end example
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@end itemize
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@section aformat
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Convert the input audio to one of the specified formats. The framework will
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negotiate the most appropriate format to minimize conversions.
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The filter accepts the following named parameters:
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@table @option
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@item sample_fmts
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A comma-separated list of requested sample formats.
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@item sample_rates
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A comma-separated list of requested sample rates.
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@item channel_layouts
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A comma-separated list of requested channel layouts.
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@end table
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If a parameter is omitted, all values are allowed.
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For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
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@example
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aformat=sample_fmts\=u8\,s16:channel_layouts\=stereo
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@end example
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@section amerge
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Merge two or more audio streams into a single multi-channel stream.
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The filter accepts the following named options:
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@table @option
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@item inputs
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Set the number of inputs. Default is 2.
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@end table
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If the channel layouts of the inputs are disjoint, and therefore compatible,
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the channel layout of the output will be set accordingly and the channels
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will be reordered as necessary. If the channel layouts of the inputs are not
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disjoint, the output will have all the channels of the first input then all
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the channels of the second input, in that order, and the channel layout of
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the output will be the default value corresponding to the total number of
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channels.
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For example, if the first input is in 2.1 (FL+FR+LF) and the second input
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is FC+BL+BR, then the output will be in 5.1, with the channels in the
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following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
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first input, b1 is the first channel of the second input).
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On the other hand, if both input are in stereo, the output channels will be
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in the default order: a1, a2, b1, b2, and the channel layout will be
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arbitrarily set to 4.0, which may or may not be the expected value.
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All inputs must have the same sample rate, and format.
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If inputs do not have the same duration, the output will stop with the
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shortest.
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Example: merge two mono files into a stereo stream:
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@example
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amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
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@end example
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Example: multiple merges:
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@example
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ffmpeg -f lavfi -i "
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amovie=input.mkv:si=0 [a0];
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amovie=input.mkv:si=1 [a1];
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amovie=input.mkv:si=2 [a2];
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amovie=input.mkv:si=3 [a3];
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amovie=input.mkv:si=4 [a4];
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amovie=input.mkv:si=5 [a5];
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[a0][a1][a2][a3][a4][a5] amerge=inputs=6" -c:a pcm_s16le output.mkv
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@end example
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@section amix
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Mixes multiple audio inputs into a single output.
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For example
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@example
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ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
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@end example
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will mix 3 input audio streams to a single output with the same duration as the
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first input and a dropout transition time of 3 seconds.
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The filter accepts the following named parameters:
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@table @option
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@item inputs
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Number of inputs. If unspecified, it defaults to 2.
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@item duration
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How to determine the end-of-stream.
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@table @option
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@item longest
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Duration of longest input. (default)
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@item shortest
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Duration of shortest input.
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@item first
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Duration of first input.
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@end table
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@item dropout_transition
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Transition time, in seconds, for volume renormalization when an input
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stream ends. The default value is 2 seconds.
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@end table
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@section anull
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Pass the audio source unchanged to the output.
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@section aresample
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Resample the input audio to the specified sample rate.
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The filter accepts exactly one parameter, the output sample rate. If not
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specified then the filter will automatically convert between its input
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and output sample rates.
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For example, to resample the input audio to 44100Hz:
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@example
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aresample=44100
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@end example
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@section asetnsamples
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Set the number of samples per each output audio frame.
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The last output packet may contain a different number of samples, as
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the filter will flush all the remaining samples when the input audio
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signal its end.
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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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@table @option
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@item nb_out_samples, n
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Set the number of frames per each output audio frame. The number is
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intended as the number of samples @emph{per each channel}.
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Default value is 1024.
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@item pad, p
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If set to 1, the filter will pad the last audio frame with zeroes, so
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that the last frame will contain the same number of samples as the
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previous ones. Default value is 1.
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@end table
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For example, to set the number of per-frame samples to 1234 and
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disable padding for the last frame, use:
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@example
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asetnsamples=n=1234:p=0
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@end example
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@section ashowinfo
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Show a line containing various information for each input audio frame.
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The input audio is not modified.
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The shown line contains a sequence of key/value pairs of the form
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@var{key}:@var{value}.
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A description of each shown parameter follows:
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@table @option
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@item n
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sequential number of the input frame, starting from 0
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@item pts
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Presentation timestamp of the input frame, in time base units; the time base
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depends on the filter input pad, and is usually 1/@var{sample_rate}.
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@item pts_time
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presentation timestamp of the input frame in seconds
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@item pos
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position of the frame in the input stream, -1 if this information in
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unavailable and/or meaningless (for example in case of synthetic audio)
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@item fmt
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sample format
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@item chlayout
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channel layout
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@item rate
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sample rate for the audio frame
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@item nb_samples
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number of samples (per channel) in the frame
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@item checksum
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Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
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the data is treated as if all the planes were concatenated.
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@item plane_checksums
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A list of Adler-32 checksums for each data plane.
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@end table
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@section asplit
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Split input audio into several identical outputs.
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The filter accepts a single parameter which specifies the number of outputs. If
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unspecified, it defaults to 2.
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For example:
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@example
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[in] asplit [out0][out1]
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@end example
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will create two separate outputs from the same input.
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To create 3 or more outputs, you need to specify the number of
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outputs, like in:
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@example
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[in] asplit=3 [out0][out1][out2]
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@end example
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@example
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|
ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
|
|
@end example
|
|
will create 5 copies of the input audio.
|
|
|
|
|
|
@section astreamsync
|
|
|
|
Forward two audio streams and control the order the buffers are forwarded.
|
|
|
|
The argument to the filter is an expression deciding which stream should be
|
|
forwarded next: if the result is negative, the first stream is forwarded; if
|
|
the result is positive or zero, the second stream is forwarded. It can use
|
|
the following variables:
|
|
|
|
@table @var
|
|
@item b1 b2
|
|
number of buffers forwarded so far on each stream
|
|
@item s1 s2
|
|
number of samples forwarded so far on each stream
|
|
@item t1 t2
|
|
current timestamp of each stream
|
|
@end table
|
|
|
|
The default value is @code{t1-t2}, which means to always forward the stream
|
|
that has a smaller timestamp.
|
|
|
|
Example: stress-test @code{amerge} by randomly sending buffers on the wrong
|
|
input, while avoiding too much of a desynchronization:
|
|
@example
|
|
amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
|
|
[a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
|
|
[a2] [b2] amerge
|
|
@end example
|
|
|
|
@section atempo
|
|
|
|
Adjust audio tempo.
|
|
|
|
The filter accepts exactly one parameter, the audio tempo. If not
|
|
specified then the filter will assume nominal 1.0 tempo. Tempo must
|
|
be in the [0.5, 2.0] range.
|
|
|
|
For example, to slow down audio to 80% tempo:
|
|
@example
|
|
atempo=0.8
|
|
@end example
|
|
|
|
For example, to speed up audio to 125% tempo:
|
|
@example
|
|
atempo=1.25
|
|
@end example
|
|
|
|
@section earwax
|
|
|
|
Make audio easier to listen to on headphones.
|
|
|
|
This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
|
|
so that when listened to on headphones the stereo image is moved from
|
|
inside your head (standard for headphones) to outside and in front of
|
|
the listener (standard for speakers).
|
|
|
|
Ported from SoX.
|
|
|
|
@section pan
|
|
|
|
Mix channels with specific gain levels. The filter accepts the output
|
|
channel layout followed by a set of channels definitions.
|
|
|
|
This filter is also designed to remap efficiently the channels of an audio
|
|
stream.
|
|
|
|
The filter accepts parameters of the form:
|
|
"@var{l}:@var{outdef}:@var{outdef}:..."
|
|
|
|
@table @option
|
|
@item l
|
|
output channel layout or number of channels
|
|
|
|
@item outdef
|
|
output channel specification, of the form:
|
|
"@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
|
|
|
|
@item out_name
|
|
output channel to define, either a channel name (FL, FR, etc.) or a channel
|
|
number (c0, c1, etc.)
|
|
|
|
@item gain
|
|
multiplicative coefficient for the channel, 1 leaving the volume unchanged
|
|
|
|
@item in_name
|
|
input channel to use, see out_name for details; it is not possible to mix
|
|
named and numbered input channels
|
|
@end table
|
|
|
|
If the `=' in a channel specification is replaced by `<', then the gains for
|
|
that specification will be renormalized so that the total is 1, thus
|
|
avoiding clipping noise.
|
|
|
|
@subsection Mixing examples
|
|
|
|
For example, if you want to down-mix from stereo to mono, but with a bigger
|
|
factor for the left channel:
|
|
@example
|
|
pan=1:c0=0.9*c0+0.1*c1
|
|
@end example
|
|
|
|
A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
|
|
7-channels surround:
|
|
@example
|
|
pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
|
|
@end example
|
|
|
|
Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
|
|
that should be preferred (see "-ac" option) unless you have very specific
|
|
needs.
|
|
|
|
@subsection Remapping examples
|
|
|
|
The channel remapping will be effective if, and only if:
|
|
|
|
@itemize
|
|
@item gain coefficients are zeroes or ones,
|
|
@item only one input per channel output,
|
|
@end itemize
|
|
|
|
If all these conditions are satisfied, the filter will notify the user ("Pure
|
|
channel mapping detected"), and use an optimized and lossless method to do the
|
|
remapping.
|
|
|
|
For example, if you have a 5.1 source and want a stereo audio stream by
|
|
dropping the extra channels:
|
|
@example
|
|
pan="stereo: c0=FL : c1=FR"
|
|
@end example
|
|
|
|
Given the same source, you can also switch front left and front right channels
|
|
and keep the input channel layout:
|
|
@example
|
|
pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
|
|
@end example
|
|
|
|
If the input is a stereo audio stream, you can mute the front left channel (and
|
|
still keep the stereo channel layout) with:
|
|
@example
|
|
pan="stereo:c1=c1"
|
|
@end example
|
|
|
|
Still with a stereo audio stream input, you can copy the right channel in both
|
|
front left and right:
|
|
@example
|
|
pan="stereo: c0=FR : c1=FR"
|
|
@end example
|
|
|
|
@section silencedetect
|
|
|
|
Detect silence in an audio stream.
|
|
|
|
This filter logs a message when it detects that the input audio volume is less
|
|
or equal to a noise tolerance value for a duration greater or equal to the
|
|
minimum detected noise duration.
|
|
|
|
The printed times and duration are expressed in seconds.
|
|
|
|
@table @option
|
|
@item duration, d
|
|
Set silence duration until notification (default is 2 seconds).
|
|
|
|
@item noise, n
|
|
Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
|
|
specified value) or amplitude ratio. Default is -60dB, or 0.001.
|
|
@end table
|
|
|
|
Detect 5 seconds of silence with -50dB noise tolerance:
|
|
@example
|
|
silencedetect=n=-50dB:d=5
|
|
@end example
|
|
|
|
Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
|
|
tolerance in @file{silence.mp3}:
|
|
@example
|
|
ffmpeg -f lavfi -i amovie=silence.mp3,silencedetect=noise=0.0001 -f null -
|
|
@end example
|
|
|
|
@section volume
|
|
|
|
Adjust the input audio volume.
|
|
|
|
The filter accepts exactly one parameter @var{vol}, which expresses
|
|
how the audio volume will be increased or decreased.
|
|
|
|
Output values are clipped to the maximum value.
|
|
|
|
If @var{vol} is expressed as a decimal number, the output audio
|
|
volume is given by the relation:
|
|
@example
|
|
@var{output_volume} = @var{vol} * @var{input_volume}
|
|
@end example
|
|
|
|
If @var{vol} is expressed as a decimal number followed by the string
|
|
"dB", the value represents the requested change in decibels of the
|
|
input audio power, and the output audio volume is given by the
|
|
relation:
|
|
@example
|
|
@var{output_volume} = 10^(@var{vol}/20) * @var{input_volume}
|
|
@end example
|
|
|
|
Otherwise @var{vol} is considered an expression and its evaluated
|
|
value is used for computing the output audio volume according to the
|
|
first relation.
|
|
|
|
Default value for @var{vol} is 1.0.
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Half the input audio volume:
|
|
@example
|
|
volume=0.5
|
|
@end example
|
|
|
|
The above example is equivalent to:
|
|
@example
|
|
volume=1/2
|
|
@end example
|
|
|
|
@item
|
|
Decrease input audio power by 12 decibels:
|
|
@example
|
|
volume=-12dB
|
|
@end example
|
|
@end itemize
|
|
|
|
@section volumedetect
|
|
|
|
Detect the volume of the input video.
|
|
|
|
The filter has no parameters. The input is not modified. Statistics about
|
|
the volume will be printed in the log when the input stream end is reached.
|
|
|
|
In particular it will show the mean volume (root mean square), maximum
|
|
volume (on a per-sample basis), and the beginning of an histogram of the
|
|
registered volume values (from the maximum value to a cumulated 1/1000 of
|
|
the samples).
|
|
|
|
All volumes are in decibels relative to the maximum PCM value.
|
|
|
|
Here is an excerpt of the output:
|
|
@example
|
|
[Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
|
|
[Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
|
|
[Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
|
|
[Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
|
|
[Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
|
|
[Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
|
|
[Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
|
|
[Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
|
|
[Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
|
|
@end example
|
|
|
|
It means that:
|
|
@itemize
|
|
@item
|
|
The mean square energy is approximately -27 dB, or 10^-2.7.
|
|
@item
|
|
The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
|
|
@item
|
|
There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
|
|
@end itemize
|
|
|
|
In other words, raising the volume by +4 dB does not cause any clipping,
|
|
raising it by +5 dB causes clipping for 6 samples, etc.
|
|
|
|
@section asyncts
|
|
Synchronize audio data with timestamps by squeezing/stretching it and/or
|
|
dropping samples/adding silence when needed.
|
|
|
|
The filter accepts the following named parameters:
|
|
@table @option
|
|
|
|
@item compensate
|
|
Enable stretching/squeezing the data to make it match the timestamps. Disabled
|
|
by default. When disabled, time gaps are covered with silence.
|
|
|
|
@item min_delta
|
|
Minimum difference between timestamps and audio data (in seconds) to trigger
|
|
adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
|
|
this filter, try setting this parameter to 0.
|
|
|
|
@item max_comp
|
|
Maximum compensation in samples per second. Relevant only with compensate=1.
|
|
Default value 500.
|
|
|
|
@item first_pts
|
|
Assume the first pts should be this value.
|
|
This allows for padding/trimming at the start of stream. By default, no
|
|
assumption is made about the first frame's expected pts, so no padding or
|
|
trimming is done. For example, this could be set to 0 to pad the beginning with
|
|
silence if an audio stream starts after the video stream.
|
|
|
|
@end table
|
|
|
|
@section channelsplit
|
|
Split each channel in input audio stream into a separate output stream.
|
|
|
|
This filter accepts the following named parameters:
|
|
@table @option
|
|
@item channel_layout
|
|
Channel layout of the input stream. Default is "stereo".
|
|
@end table
|
|
|
|
For example, assuming a stereo input MP3 file
|
|
@example
|
|
ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
|
|
@end example
|
|
will create an output Matroska file with two audio streams, one containing only
|
|
the left channel and the other the right channel.
|
|
|
|
To split a 5.1 WAV file into per-channel files
|
|
@example
|
|
ffmpeg -i in.wav -filter_complex
|
|
'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
|
|
-map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
|
|
front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
|
|
side_right.wav
|
|
@end example
|
|
|
|
@section channelmap
|
|
Remap input channels to new locations.
|
|
|
|
This filter accepts the following named parameters:
|
|
@table @option
|
|
@item channel_layout
|
|
Channel layout of the output stream.
|
|
|
|
@item map
|
|
Map channels from input to output. The argument is a comma-separated list of
|
|
mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
|
|
@var{in_channel} form. @var{in_channel} can be either the name of the input
|
|
channel (e.g. FL for front left) or its index in the input channel layout.
|
|
@var{out_channel} is the name of the output channel or its index in the output
|
|
channel layout. If @var{out_channel} is not given then it is implicitly an
|
|
index, starting with zero and increasing by one for each mapping.
|
|
@end table
|
|
|
|
If no mapping is present, the filter will implicitly map input channels to
|
|
output channels preserving index.
|
|
|
|
For example, assuming a 5.1+downmix input MOV file
|
|
@example
|
|
ffmpeg -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav
|
|
@end example
|
|
will create an output WAV file tagged as stereo from the downmix channels of
|
|
the input.
|
|
|
|
To fix a 5.1 WAV improperly encoded in AAC's native channel order
|
|
@example
|
|
ffmpeg -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav
|
|
@end example
|
|
|
|
@section join
|
|
Join multiple input streams into one multi-channel stream.
|
|
|
|
The filter accepts the following named parameters:
|
|
@table @option
|
|
|
|
@item inputs
|
|
Number of input streams. Defaults to 2.
|
|
|
|
@item channel_layout
|
|
Desired output channel layout. Defaults to stereo.
|
|
|
|
@item map
|
|
Map channels from inputs to output. The argument is a comma-separated list of
|
|
mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
|
|
form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
|
|
can be either the name of the input channel (e.g. FL for front left) or its
|
|
index in the specified input stream. @var{out_channel} is the name of the output
|
|
channel.
|
|
@end table
|
|
|
|
The filter will attempt to guess the mappings when those are not specified
|
|
explicitly. It does so by first trying to find an unused matching input channel
|
|
and if that fails it picks the first unused input channel.
|
|
|
|
E.g. to join 3 inputs (with properly set channel layouts)
|
|
@example
|
|
ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
|
|
@end example
|
|
|
|
To build a 5.1 output from 6 single-channel streams:
|
|
@example
|
|
ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
|
|
'join=inputs=6:channel_layout=5.1:map=0.0-FL\,1.0-FR\,2.0-FC\,3.0-SL\,4.0-SR\,5.0-LFE'
|
|
out
|
|
@end example
|
|
|
|
@section resample
|
|
Convert the audio sample format, sample rate and channel layout. This filter is
|
|
not meant to be used directly.
|
|
|
|
@c man end AUDIO FILTERS
|
|
|
|
@chapter Audio Sources
|
|
@c man begin AUDIO SOURCES
|
|
|
|
Below is a description of the currently available audio sources.
|
|
|
|
@section abuffer
|
|
|
|
Buffer audio frames, and make them available to the filter chain.
|
|
|
|
This source is mainly intended for a programmatic use, in particular
|
|
through the interface defined in @file{libavfilter/asrc_abuffer.h}.
|
|
|
|
It accepts the following mandatory parameters:
|
|
@var{sample_rate}:@var{sample_fmt}:@var{channel_layout}
|
|
|
|
@table @option
|
|
|
|
@item sample_rate
|
|
The sample rate of the incoming audio buffers.
|
|
|
|
@item sample_fmt
|
|
The sample format of the incoming audio buffers.
|
|
Either a sample format name or its corresponging integer representation from
|
|
the enum AVSampleFormat in @file{libavutil/samplefmt.h}
|
|
|
|
@item channel_layout
|
|
The channel layout of the incoming audio buffers.
|
|
Either a channel layout name from channel_layout_map in
|
|
@file{libavutil/channel_layout.c} or its corresponding integer representation
|
|
from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
|
|
|
|
@end table
|
|
|
|
For example:
|
|
@example
|
|
abuffer=44100:s16p:stereo
|
|
@end example
|
|
|
|
will instruct the source to accept planar 16bit signed stereo at 44100Hz.
|
|
Since the sample format with name "s16p" corresponds to the number
|
|
6 and the "stereo" channel layout corresponds to the value 0x3, this is
|
|
equivalent to:
|
|
@example
|
|
abuffer=44100:6:0x3
|
|
@end example
|
|
|
|
@section aevalsrc
|
|
|
|
Generate an audio signal specified by an expression.
|
|
|
|
This source accepts in input one or more expressions (one for each
|
|
channel), which are evaluated and used to generate a corresponding
|
|
audio signal.
|
|
|
|
It accepts the syntax: @var{exprs}[::@var{options}].
|
|
@var{exprs} is a list of expressions separated by ":", one for each
|
|
separate channel. In case the @var{channel_layout} is not
|
|
specified, the selected channel layout depends on the number of
|
|
provided expressions.
|
|
|
|
@var{options} is an optional sequence of @var{key}=@var{value} pairs,
|
|
separated by ":".
|
|
|
|
The description of the accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item channel_layout, c
|
|
Set the channel layout. The number of channels in the specified layout
|
|
must be equal to the number of specified expressions.
|
|
|
|
@item duration, d
|
|
Set the minimum duration of the sourced audio. See the function
|
|
@code{av_parse_time()} for the accepted format.
|
|
Note that the resulting duration may be greater than the specified
|
|
duration, as the generated audio is always cut at the end of a
|
|
complete frame.
|
|
|
|
If not specified, or the expressed duration is negative, the audio is
|
|
supposed to be generated forever.
|
|
|
|
@item nb_samples, n
|
|
Set the number of samples per channel per each output frame,
|
|
default to 1024.
|
|
|
|
@item sample_rate, s
|
|
Specify the sample rate, default to 44100.
|
|
@end table
|
|
|
|
Each expression in @var{exprs} can contain the following constants:
|
|
|
|
@table @option
|
|
@item n
|
|
number of the evaluated sample, starting from 0
|
|
|
|
@item t
|
|
time of the evaluated sample expressed in seconds, starting from 0
|
|
|
|
@item s
|
|
sample rate
|
|
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
|
|
@item
|
|
Generate silence:
|
|
@example
|
|
aevalsrc=0
|
|
@end example
|
|
|
|
@item
|
|
|
|
Generate a sin signal with frequency of 440 Hz, set sample rate to
|
|
8000 Hz:
|
|
@example
|
|
aevalsrc="sin(440*2*PI*t)::s=8000"
|
|
@end example
|
|
|
|
@item
|
|
Generate a two channels signal, specify the channel layout (Front
|
|
Center + Back Center) explicitly:
|
|
@example
|
|
aevalsrc="sin(420*2*PI*t):cos(430*2*PI*t)::c=FC|BC"
|
|
@end example
|
|
|
|
@item
|
|
Generate white noise:
|
|
@example
|
|
aevalsrc="-2+random(0)"
|
|
@end example
|
|
|
|
@item
|
|
Generate an amplitude modulated signal:
|
|
@example
|
|
aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
|
|
@end example
|
|
|
|
@item
|
|
Generate 2.5 Hz binaural beats on a 360 Hz carrier:
|
|
@example
|
|
aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) : 0.1*sin(2*PI*(360+2.5/2)*t)"
|
|
@end example
|
|
|
|
@end itemize
|
|
|
|
@section anullsrc
|
|
|
|
Null audio source, return unprocessed audio frames. It is mainly useful
|
|
as a template and to be employed in analysis / debugging tools, or as
|
|
the source for filters which ignore the input data (for example the sox
|
|
synth filter).
|
|
|
|
It accepts an optional sequence of @var{key}=@var{value} pairs,
|
|
separated by ":".
|
|
|
|
The description of the accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item sample_rate, s
|
|
Specify the sample rate, and defaults to 44100.
|
|
|
|
@item channel_layout, cl
|
|
|
|
Specify the channel layout, and can be either an integer or a string
|
|
representing a channel layout. The default value of @var{channel_layout}
|
|
is "stereo".
|
|
|
|
Check the channel_layout_map definition in
|
|
@file{libavutil/channel_layout.c} for the mapping between strings and
|
|
channel layout values.
|
|
|
|
@item nb_samples, n
|
|
Set the number of samples per requested frames.
|
|
|
|
@end table
|
|
|
|
Follow some examples:
|
|
@example
|
|
# set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
|
|
anullsrc=r=48000:cl=4
|
|
|
|
# same as
|
|
anullsrc=r=48000:cl=mono
|
|
@end example
|
|
|
|
@section abuffer
|
|
Buffer audio frames, and make them available to the filter chain.
|
|
|
|
This source is not intended to be part of user-supplied graph descriptions but
|
|
for insertion by calling programs through the interface defined in
|
|
@file{libavfilter/buffersrc.h}.
|
|
|
|
It accepts the following named parameters:
|
|
@table @option
|
|
|
|
@item time_base
|
|
Timebase which will be used for timestamps of submitted frames. It must be
|
|
either a floating-point number or in @var{numerator}/@var{denominator} form.
|
|
|
|
@item sample_rate
|
|
Audio sample rate.
|
|
|
|
@item sample_fmt
|
|
Name of the sample format, as returned by @code{av_get_sample_fmt_name()}.
|
|
|
|
@item channel_layout
|
|
Channel layout of the audio data, in the form that can be accepted by
|
|
@code{av_get_channel_layout()}.
|
|
@end table
|
|
|
|
All the parameters need to be explicitly defined.
|
|
|
|
@section flite
|
|
|
|
Synthesize a voice utterance using the libflite library.
|
|
|
|
To enable compilation of this filter you need to configure FFmpeg with
|
|
@code{--enable-libflite}.
|
|
|
|
Note that the flite library is not thread-safe.
|
|
|
|
The source accepts parameters as a list of @var{key}=@var{value} pairs,
|
|
separated by ":".
|
|
|
|
The description of the accepted parameters follows.
|
|
|
|
@table @option
|
|
|
|
@item list_voices
|
|
If set to 1, list the names of the available voices and exit
|
|
immediately. Default value is 0.
|
|
|
|
@item nb_samples, n
|
|
Set the maximum number of samples per frame. Default value is 512.
|
|
|
|
@item textfile
|
|
Set the filename containing the text to speak.
|
|
|
|
@item text
|
|
Set the text to speak.
|
|
|
|
@item voice, v
|
|
Set the voice to use for the speech synthesis. Default value is
|
|
@code{kal}. See also the @var{list_voices} option.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Read from file @file{speech.txt}, and synthetize the text using the
|
|
standard flite voice:
|
|
@example
|
|
flite=textfile=speech.txt
|
|
@end example
|
|
|
|
@item
|
|
Read the specified text selecting the @code{slt} voice:
|
|
@example
|
|
flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
|
|
@end example
|
|
|
|
@item
|
|
Input text to ffmpeg:
|
|
@example
|
|
ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
|
|
@end example
|
|
|
|
@item
|
|
Make @file{ffplay} speak the specified text, using @code{flite} and
|
|
the @code{lavfi} device:
|
|
@example
|
|
ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
|
|
@end example
|
|
@end itemize
|
|
|
|
For more information about libflite, check:
|
|
@url{http://www.speech.cs.cmu.edu/flite/}
|
|
|
|
@c man end AUDIO SOURCES
|
|
|
|
@chapter Audio Sinks
|
|
@c man begin AUDIO SINKS
|
|
|
|
Below is a description of the currently available audio sinks.
|
|
|
|
@section abuffersink
|
|
|
|
Buffer audio frames, and make them available to the end of filter chain.
|
|
|
|
This sink is mainly intended for programmatic use, in particular
|
|
through the interface defined in @file{libavfilter/buffersink.h}.
|
|
|
|
It requires a pointer to an AVABufferSinkContext structure, which
|
|
defines the incoming buffers' formats, to be passed as the opaque
|
|
parameter to @code{avfilter_init_filter} for initialization.
|
|
|
|
@section anullsink
|
|
|
|
Null audio sink, do absolutely nothing with the input audio. It is
|
|
mainly useful as a template and to be employed in analysis / debugging
|
|
tools.
|
|
|
|
@section abuffersink
|
|
This sink is intended for programmatic use. Frames that arrive on this sink can
|
|
be retrieved by the calling program using the interface defined in
|
|
@file{libavfilter/buffersink.h}.
|
|
|
|
This filter accepts no parameters.
|
|
|
|
@c man end AUDIO SINKS
|
|
|
|
@chapter Video Filters
|
|
@c man begin VIDEO FILTERS
|
|
|
|
When you configure your FFmpeg build, you can disable any of the
|
|
existing filters using @code{--disable-filters}.
|
|
The configure output will show the video filters included in your
|
|
build.
|
|
|
|
Below is a description of the currently available video filters.
|
|
|
|
@section alphaextract
|
|
|
|
Extract the alpha component from the input as a grayscale video. This
|
|
is especially useful with the @var{alphamerge} filter.
|
|
|
|
@section alphamerge
|
|
|
|
Add or replace the alpha component of the primary input with the
|
|
grayscale value of a second input. This is intended for use with
|
|
@var{alphaextract} to allow the transmission or storage of frame
|
|
sequences that have alpha in a format that doesn't support an alpha
|
|
channel.
|
|
|
|
For example, to reconstruct full frames from a normal YUV-encoded video
|
|
and a separate video created with @var{alphaextract}, you might use:
|
|
@example
|
|
movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
|
|
@end example
|
|
|
|
Since this filter is designed for reconstruction, it operates on frame
|
|
sequences without considering timestamps, and terminates when either
|
|
input reaches end of stream. This will cause problems if your encoding
|
|
pipeline drops frames. If you're trying to apply an image as an
|
|
overlay to a video stream, consider the @var{overlay} filter instead.
|
|
|
|
@section ass
|
|
|
|
Draw ASS (Advanced Substation Alpha) subtitles on top of input video
|
|
using the libass library.
|
|
|
|
To enable compilation of this filter you need to configure FFmpeg with
|
|
@code{--enable-libass}.
|
|
|
|
This filter accepts the following named options, expressed as a
|
|
sequence of @var{key}=@var{value} pairs, separated by ":".
|
|
|
|
@table @option
|
|
@item filename, f
|
|
Set the filename of the ASS file to read. It must be specified.
|
|
|
|
@item original_size
|
|
Specify the size of the original video, the video for which the ASS file
|
|
was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
|
|
necessary to correctly scale the fonts if the aspect ratio has been changed.
|
|
@end table
|
|
|
|
If the first key is not specified, it is assumed that the first value
|
|
specifies the @option{filename}.
|
|
|
|
For example, to render the file @file{sub.ass} on top of the input
|
|
video, use the command:
|
|
@example
|
|
ass=sub.ass
|
|
@end example
|
|
|
|
which is equivalent to:
|
|
@example
|
|
ass=filename=sub.ass
|
|
@end example
|
|
|
|
@section bbox
|
|
|
|
Compute the bounding box for the non-black pixels in the input frame
|
|
luminance plane.
|
|
|
|
This filter computes the bounding box containing all the pixels with a
|
|
luminance value greater than the minimum allowed value.
|
|
The parameters describing the bounding box are printed on the filter
|
|
log.
|
|
|
|
@section blackdetect
|
|
|
|
Detect video intervals that are (almost) completely black. Can be
|
|
useful to detect chapter transitions, commercials, or invalid
|
|
recordings. Output lines contains the time for the start, end and
|
|
duration of the detected black interval expressed in seconds.
|
|
|
|
In order to display the output lines, you need to set the loglevel at
|
|
least to the AV_LOG_INFO value.
|
|
|
|
This filter accepts a list of options in the form of
|
|
@var{key}=@var{value} pairs separated by ":". A description of the
|
|
accepted options follows.
|
|
|
|
@table @option
|
|
@item black_min_duration, d
|
|
Set the minimum detected black duration expressed in seconds. It must
|
|
be a non-negative floating point number.
|
|
|
|
Default value is 2.0.
|
|
|
|
@item picture_black_ratio_th, pic_th
|
|
Set the threshold for considering a picture "black".
|
|
Express the minimum value for the ratio:
|
|
@example
|
|
@var{nb_black_pixels} / @var{nb_pixels}
|
|
@end example
|
|
|
|
for which a picture is considered black.
|
|
Default value is 0.98.
|
|
|
|
@item pixel_black_th, pix_th
|
|
Set the threshold for considering a pixel "black".
|
|
|
|
The threshold expresses the maximum pixel luminance value for which a
|
|
pixel is considered "black". The provided value is scaled according to
|
|
the following equation:
|
|
@example
|
|
@var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
|
|
@end example
|
|
|
|
@var{luminance_range_size} and @var{luminance_minimum_value} depend on
|
|
the input video format, the range is [0-255] for YUV full-range
|
|
formats and [16-235] for YUV non full-range formats.
|
|
|
|
Default value is 0.10.
|
|
@end table
|
|
|
|
The following example sets the maximum pixel threshold to the minimum
|
|
value, and detects only black intervals of 2 or more seconds:
|
|
@example
|
|
blackdetect=d=2:pix_th=0.00
|
|
@end example
|
|
|
|
@section blackframe
|
|
|
|
Detect frames that are (almost) completely black. Can be useful to
|
|
detect chapter transitions or commercials. Output lines consist of
|
|
the frame number of the detected frame, the percentage of blackness,
|
|
the position in the file if known or -1 and the timestamp in seconds.
|
|
|
|
In order to display the output lines, you need to set the loglevel at
|
|
least to the AV_LOG_INFO value.
|
|
|
|
The filter accepts the syntax:
|
|
@example
|
|
blackframe[=@var{amount}:[@var{threshold}]]
|
|
@end example
|
|
|
|
@var{amount} is the percentage of the pixels that have to be below the
|
|
threshold, and defaults to 98.
|
|
|
|
@var{threshold} is the threshold below which a pixel value is
|
|
considered black, and defaults to 32.
|
|
|
|
@section boxblur
|
|
|
|
Apply boxblur algorithm to the input video.
|
|
|
|
This filter accepts the parameters:
|
|
@var{luma_radius}:@var{luma_power}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
|
|
|
|
Chroma and alpha parameters are optional, if not specified they default
|
|
to the corresponding values set for @var{luma_radius} and
|
|
@var{luma_power}.
|
|
|
|
@var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
|
|
the radius in pixels of the box used for blurring the corresponding
|
|
input plane. They are expressions, and can contain the following
|
|
constants:
|
|
@table @option
|
|
@item w, h
|
|
the input width and height in pixels
|
|
|
|
@item cw, ch
|
|
the input chroma image width and height in pixels
|
|
|
|
@item hsub, vsub
|
|
horizontal and vertical chroma subsample values. For example for the
|
|
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
|
@end table
|
|
|
|
The radius must be a non-negative number, and must not be greater than
|
|
the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
|
|
and of @code{min(cw,ch)/2} for the chroma planes.
|
|
|
|
@var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
|
|
how many times the boxblur filter is applied to the corresponding
|
|
plane.
|
|
|
|
Some examples follow:
|
|
|
|
@itemize
|
|
|
|
@item
|
|
Apply a boxblur filter with luma, chroma, and alpha radius
|
|
set to 2:
|
|
@example
|
|
boxblur=2:1
|
|
@end example
|
|
|
|
@item
|
|
Set luma radius to 2, alpha and chroma radius to 0
|
|
@example
|
|
boxblur=2:1:0:0:0:0
|
|
@end example
|
|
|
|
@item
|
|
Set luma and chroma radius to a fraction of the video dimension
|
|
@example
|
|
boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
|
|
@end example
|
|
|
|
@end itemize
|
|
|
|
@section colormatrix
|
|
|
|
The colormatrix filter allows conversion between any of the following color
|
|
space: BT.709 (@var{bt709}), BT.601 (@var{bt601}), SMPTE-240M (@var{smpte240m})
|
|
and FCC (@var{fcc}).
|
|
|
|
The syntax of the parameters is @var{source}:@var{destination}:
|
|
|
|
@example
|
|
colormatrix=bt601:smpte240m
|
|
@end example
|
|
|
|
@section copy
|
|
|
|
Copy the input source unchanged to the output. Mainly useful for
|
|
testing purposes.
|
|
|
|
@section crop
|
|
|
|
Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}
|
|
|
|
The @var{keep_aspect} parameter is optional, if specified and set to a
|
|
non-zero value will force the output display aspect ratio to be the
|
|
same of the input, by changing the output sample aspect ratio.
|
|
|
|
The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
|
|
expressions containing the following constants:
|
|
|
|
@table @option
|
|
@item x, y
|
|
the computed values for @var{x} and @var{y}. They are evaluated for
|
|
each new frame.
|
|
|
|
@item in_w, in_h
|
|
the input width and height
|
|
|
|
@item iw, ih
|
|
same as @var{in_w} and @var{in_h}
|
|
|
|
@item out_w, out_h
|
|
the output (cropped) width and height
|
|
|
|
@item ow, oh
|
|
same as @var{out_w} and @var{out_h}
|
|
|
|
@item a
|
|
same as @var{iw} / @var{ih}
|
|
|
|
@item sar
|
|
input sample aspect ratio
|
|
|
|
@item dar
|
|
input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
|
|
|
|
@item hsub, vsub
|
|
horizontal and vertical chroma subsample values. For example for the
|
|
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
|
|
|
@item n
|
|
the number of input frame, starting from 0
|
|
|
|
@item pos
|
|
the position in the file of the input frame, NAN if unknown
|
|
|
|
@item t
|
|
timestamp expressed in seconds, NAN if the input timestamp is unknown
|
|
|
|
@end table
|
|
|
|
The @var{out_w} and @var{out_h} parameters specify the expressions for
|
|
the width and height of the output (cropped) video. They are
|
|
evaluated just at the configuration of the filter.
|
|
|
|
The default value of @var{out_w} is "in_w", and the default value of
|
|
@var{out_h} is "in_h".
|
|
|
|
The expression for @var{out_w} may depend on the value of @var{out_h},
|
|
and the expression for @var{out_h} may depend on @var{out_w}, but they
|
|
cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
|
|
evaluated after @var{out_w} and @var{out_h}.
|
|
|
|
The @var{x} and @var{y} parameters specify the expressions for the
|
|
position of the top-left corner of the output (non-cropped) area. They
|
|
are evaluated for each frame. If the evaluated value is not valid, it
|
|
is approximated to the nearest valid value.
|
|
|
|
The default value of @var{x} is "(in_w-out_w)/2", and the default
|
|
value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
|
|
the center of the input image.
|
|
|
|
The expression for @var{x} may depend on @var{y}, and the expression
|
|
for @var{y} may depend on @var{x}.
|
|
|
|
Follow some examples:
|
|
@example
|
|
# crop the central input area with size 100x100
|
|
crop=100:100
|
|
|
|
# crop the central input area with size 2/3 of the input video
|
|
"crop=2/3*in_w:2/3*in_h"
|
|
|
|
# crop the input video central square
|
|
crop=in_h
|
|
|
|
# delimit the rectangle with the top-left corner placed at position
|
|
# 100:100 and the right-bottom corner corresponding to the right-bottom
|
|
# corner of the input image.
|
|
crop=in_w-100:in_h-100:100:100
|
|
|
|
# crop 10 pixels from the left and right borders, and 20 pixels from
|
|
# the top and bottom borders
|
|
"crop=in_w-2*10:in_h-2*20"
|
|
|
|
# keep only the bottom right quarter of the input image
|
|
"crop=in_w/2:in_h/2:in_w/2:in_h/2"
|
|
|
|
# crop height for getting Greek harmony
|
|
"crop=in_w:1/PHI*in_w"
|
|
|
|
# trembling effect
|
|
"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)"
|
|
|
|
# erratic camera effect depending on timestamp
|
|
"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
|
|
|
|
# set x depending on the value of y
|
|
"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
|
|
@end example
|
|
|
|
@section cropdetect
|
|
|
|
Auto-detect crop size.
|
|
|
|
Calculate necessary cropping parameters and prints the recommended
|
|
parameters through the logging system. The detected dimensions
|
|
correspond to the non-black area of the input video.
|
|
|
|
It accepts the syntax:
|
|
@example
|
|
cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
|
|
@end example
|
|
|
|
@table @option
|
|
|
|
@item limit
|
|
Threshold, which can be optionally specified from nothing (0) to
|
|
everything (255), defaults to 24.
|
|
|
|
@item round
|
|
Value which the width/height should be divisible by, defaults to
|
|
16. The offset is automatically adjusted to center the video. Use 2 to
|
|
get only even dimensions (needed for 4:2:2 video). 16 is best when
|
|
encoding to most video codecs.
|
|
|
|
@item reset
|
|
Counter that determines after how many frames cropdetect will reset
|
|
the previously detected largest video area and start over to detect
|
|
the current optimal crop area. Defaults to 0.
|
|
|
|
This can be useful when channel logos distort the video area. 0
|
|
indicates never reset and return the largest area encountered during
|
|
playback.
|
|
@end table
|
|
|
|
@section decimate
|
|
|
|
This filter drops frames that do not differ greatly from the previous
|
|
frame in order to reduce framerate. The main use of this filter is
|
|
for very-low-bitrate encoding (e.g. streaming over dialup modem), but
|
|
it could in theory be used for fixing movies that were
|
|
inverse-telecined incorrectly.
|
|
|
|
It accepts the following parameters:
|
|
@var{max}:@var{hi}:@var{lo}:@var{frac}.
|
|
|
|
@table @option
|
|
|
|
@item max
|
|
Set the maximum number of consecutive frames which can be dropped (if
|
|
positive), or the minimum interval between dropped frames (if
|
|
negative). If the value is 0, the frame is dropped unregarding the
|
|
number of previous sequentially dropped frames.
|
|
|
|
Default value is 0.
|
|
|
|
@item hi, lo, frac
|
|
Set the dropping threshold values.
|
|
|
|
Values for @var{hi} and @var{lo} are for 8x8 pixel blocks and
|
|
represent actual pixel value differences, so a threshold of 64
|
|
corresponds to 1 unit of difference for each pixel, or the same spread
|
|
out differently over the block.
|
|
|
|
A frame is a candidate for dropping if no 8x8 blocks differ by more
|
|
than a threshold of @var{hi}, and if no more than @var{frac} blocks (1
|
|
meaning the whole image) differ by more than a threshold of @var{lo}.
|
|
|
|
Default value for @var{hi} is 64*12, default value for @var{lo} is
|
|
64*5, and default value for @var{frac} is 0.33.
|
|
@end table
|
|
|
|
@section delogo
|
|
|
|
Suppress a TV station logo by a simple interpolation of the surrounding
|
|
pixels. Just set a rectangle covering the logo and watch it disappear
|
|
(and sometimes something even uglier appear - your mileage may vary).
|
|
|
|
The filter accepts parameters as a string of the form
|
|
"@var{x}:@var{y}:@var{w}:@var{h}:@var{band}", or as a list of
|
|
@var{key}=@var{value} pairs, separated by ":".
|
|
|
|
The description of the accepted parameters follows.
|
|
|
|
@table @option
|
|
|
|
@item x, y
|
|
Specify the top left corner coordinates of the logo. They must be
|
|
specified.
|
|
|
|
@item w, h
|
|
Specify the width and height of the logo to clear. They must be
|
|
specified.
|
|
|
|
@item band, t
|
|
Specify the thickness of the fuzzy edge of the rectangle (added to
|
|
@var{w} and @var{h}). The default value is 4.
|
|
|
|
@item show
|
|
When set to 1, a green rectangle is drawn on the screen to simplify
|
|
finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
|
|
@var{band} is set to 4. The default value is 0.
|
|
|
|
@end table
|
|
|
|
Some examples follow.
|
|
|
|
@itemize
|
|
|
|
@item
|
|
Set a rectangle covering the area with top left corner coordinates 0,0
|
|
and size 100x77, setting a band of size 10:
|
|
@example
|
|
delogo=0:0:100:77:10
|
|
@end example
|
|
|
|
@item
|
|
As the previous example, but use named options:
|
|
@example
|
|
delogo=x=0:y=0:w=100:h=77:band=10
|
|
@end example
|
|
|
|
@end itemize
|
|
|
|
@section deshake
|
|
|
|
Attempt to fix small changes in horizontal and/or vertical shift. This
|
|
filter helps remove camera shake from hand-holding a camera, bumping a
|
|
tripod, moving on a vehicle, etc.
|
|
|
|
The filter accepts parameters as a string of the form
|
|
"@var{x}:@var{y}:@var{w}:@var{h}:@var{rx}:@var{ry}:@var{edge}:@var{blocksize}:@var{contrast}:@var{search}:@var{filename}"
|
|
|
|
A description of the accepted parameters follows.
|
|
|
|
@table @option
|
|
|
|
@item x, y, w, h
|
|
Specify a rectangular area where to limit the search for motion
|
|
vectors.
|
|
If desired the search for motion vectors can be limited to a
|
|
rectangular area of the frame defined by its top left corner, width
|
|
and height. These parameters have the same meaning as the drawbox
|
|
filter which can be used to visualise the position of the bounding
|
|
box.
|
|
|
|
This is useful when simultaneous movement of subjects within the frame
|
|
might be confused for camera motion by the motion vector search.
|
|
|
|
If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
|
|
then the full frame is used. This allows later options to be set
|
|
without specifying the bounding box for the motion vector search.
|
|
|
|
Default - search the whole frame.
|
|
|
|
@item rx, ry
|
|
Specify the maximum extent of movement in x and y directions in the
|
|
range 0-64 pixels. Default 16.
|
|
|
|
@item edge
|
|
Specify how to generate pixels to fill blanks at the edge of the
|
|
frame. An integer from 0 to 3 as follows:
|
|
@table @option
|
|
@item 0
|
|
Fill zeroes at blank locations
|
|
@item 1
|
|
Original image at blank locations
|
|
@item 2
|
|
Extruded edge value at blank locations
|
|
@item 3
|
|
Mirrored edge at blank locations
|
|
@end table
|
|
|
|
The default setting is mirror edge at blank locations.
|
|
|
|
@item blocksize
|
|
Specify the blocksize to use for motion search. Range 4-128 pixels,
|
|
default 8.
|
|
|
|
@item contrast
|
|
Specify the contrast threshold for blocks. Only blocks with more than
|
|
the specified contrast (difference between darkest and lightest
|
|
pixels) will be considered. Range 1-255, default 125.
|
|
|
|
@item search
|
|
Specify the search strategy 0 = exhaustive search, 1 = less exhaustive
|
|
search. Default - exhaustive search.
|
|
|
|
@item filename
|
|
If set then a detailed log of the motion search is written to the
|
|
specified file.
|
|
|
|
@end table
|
|
|
|
@section drawbox
|
|
|
|
Draw a colored box on the input image.
|
|
|
|
The filter accepts parameters as a list of @var{key}=@var{value} pairs,
|
|
separated by ":".
|
|
|
|
The description of the accepted parameters follows.
|
|
|
|
@table @option
|
|
@item x, y
|
|
Specify the top left corner coordinates of the box. Default to 0.
|
|
|
|
@item width, w
|
|
@item height, h
|
|
Specify the width and height of the box, if 0 they are interpreted as
|
|
the input width and height. Default to 0.
|
|
|
|
@item color, c
|
|
Specify the color of the box to write, it can be the name of a color
|
|
(case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
|
|
value @code{invert} is used, the box edge color is the same as the
|
|
video with inverted luma.
|
|
|
|
@item thickness, t
|
|
Set the thickness of the box edge. Default value is @code{4}.
|
|
@end table
|
|
|
|
If the key of the first options is omitted, the arguments are
|
|
interpreted according to the following syntax:
|
|
@example
|
|
drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}:@var{thickness}
|
|
@end example
|
|
|
|
Some examples follow:
|
|
@itemize
|
|
@item
|
|
Draw a black box around the edge of the input image:
|
|
@example
|
|
drawbox
|
|
@end example
|
|
|
|
@item
|
|
Draw a box with color red and an opacity of 50%:
|
|
@example
|
|
drawbox=10:20:200:60:red@@0.5
|
|
@end example
|
|
|
|
The previous example can be specified as:
|
|
@example
|
|
drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
|
|
@end example
|
|
|
|
@item
|
|
Fill the box with pink color:
|
|
@example
|
|
drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
|
|
@end example
|
|
@end itemize
|
|
|
|
@anchor{drawtext}
|
|
@section drawtext
|
|
|
|
Draw text string or text from specified file on top of video using the
|
|
libfreetype library.
|
|
|
|
To enable compilation of this filter you need to configure FFmpeg with
|
|
@code{--enable-libfreetype}.
|
|
|
|
@subsection Syntax
|
|
|
|
The filter accepts parameters as a list of @var{key}=@var{value} pairs,
|
|
separated by ":".
|
|
|
|
The description of the accepted parameters follows.
|
|
|
|
@table @option
|
|
|
|
@item box
|
|
Used to draw a box around text using background color.
|
|
Value should be either 1 (enable) or 0 (disable).
|
|
The default value of @var{box} is 0.
|
|
|
|
@item boxcolor
|
|
The color to be used for drawing box around text.
|
|
Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
|
|
(e.g. "0xff00ff"), possibly followed by an alpha specifier.
|
|
The default value of @var{boxcolor} is "white".
|
|
|
|
@item draw
|
|
Set an expression which specifies if the text should be drawn. If the
|
|
expression evaluates to 0, the text is not drawn. This is useful for
|
|
specifying that the text should be drawn only when specific conditions
|
|
are met.
|
|
|
|
Default value is "1".
|
|
|
|
See below for the list of accepted constants and functions.
|
|
|
|
@item expansion
|
|
Select how the @var{text} is expanded. Can be either @code{none},
|
|
@code{strftime} (default for compatibity reasons but deprecated) or
|
|
@code{normal}. See the @ref{drawtext_expansion, Text expansion} section
|
|
below for details.
|
|
|
|
@item fix_bounds
|
|
If true, check and fix text coords to avoid clipping.
|
|
|
|
@item fontcolor
|
|
The color to be used for drawing fonts.
|
|
Either a string (e.g. "red") or in 0xRRGGBB[AA] format
|
|
(e.g. "0xff000033"), possibly followed by an alpha specifier.
|
|
The default value of @var{fontcolor} is "black".
|
|
|
|
@item fontfile
|
|
The font file to be used for drawing text. Path must be included.
|
|
This parameter is mandatory.
|
|
|
|
@item fontsize
|
|
The font size to be used for drawing text.
|
|
The default value of @var{fontsize} is 16.
|
|
|
|
@item ft_load_flags
|
|
Flags to be used for loading the fonts.
|
|
|
|
The flags map the corresponding flags supported by libfreetype, and are
|
|
a combination of the following values:
|
|
@table @var
|
|
@item default
|
|
@item no_scale
|
|
@item no_hinting
|
|
@item render
|
|
@item no_bitmap
|
|
@item vertical_layout
|
|
@item force_autohint
|
|
@item crop_bitmap
|
|
@item pedantic
|
|
@item ignore_global_advance_width
|
|
@item no_recurse
|
|
@item ignore_transform
|
|
@item monochrome
|
|
@item linear_design
|
|
@item no_autohint
|
|
@item end table
|
|
@end table
|
|
|
|
Default value is "render".
|
|
|
|
For more information consult the documentation for the FT_LOAD_*
|
|
libfreetype flags.
|
|
|
|
@item shadowcolor
|
|
The color to be used for drawing a shadow behind the drawn text. It
|
|
can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
|
|
form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
|
|
The default value of @var{shadowcolor} is "black".
|
|
|
|
@item shadowx, shadowy
|
|
The x and y offsets for the text shadow position with respect to the
|
|
position of the text. They can be either positive or negative
|
|
values. Default value for both is "0".
|
|
|
|
@item tabsize
|
|
The size in number of spaces to use for rendering the tab.
|
|
Default value is 4.
|
|
|
|
@item timecode
|
|
Set the initial timecode representation in "hh:mm:ss[:;.]ff"
|
|
format. It can be used with or without text parameter. @var{timecode_rate}
|
|
option must be specified.
|
|
|
|
@item timecode_rate, rate, r
|
|
Set the timecode frame rate (timecode only).
|
|
|
|
@item text
|
|
The text string to be drawn. The text must be a sequence of UTF-8
|
|
encoded characters.
|
|
This parameter is mandatory if no file is specified with the parameter
|
|
@var{textfile}.
|
|
|
|
@item textfile
|
|
A text file containing text to be drawn. The text must be a sequence
|
|
of UTF-8 encoded characters.
|
|
|
|
This parameter is mandatory if no text string is specified with the
|
|
parameter @var{text}.
|
|
|
|
If both @var{text} and @var{textfile} are specified, an error is thrown.
|
|
|
|
@item x, y
|
|
The expressions which specify the offsets where text will be drawn
|
|
within the video frame. They are relative to the top/left border of the
|
|
output image.
|
|
|
|
The default value of @var{x} and @var{y} is "0".
|
|
|
|
See below for the list of accepted constants and functions.
|
|
@end table
|
|
|
|
The parameters for @var{x} and @var{y} are expressions containing the
|
|
following constants and functions:
|
|
|
|
@table @option
|
|
@item dar
|
|
input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
|
|
|
|
@item hsub, vsub
|
|
horizontal and vertical chroma subsample values. For example for the
|
|
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
|
|
|
@item line_h, lh
|
|
the height of each text line
|
|
|
|
@item main_h, h, H
|
|
the input height
|
|
|
|
@item main_w, w, W
|
|
the input width
|
|
|
|
@item max_glyph_a, ascent
|
|
the maximum distance from the baseline to the highest/upper grid
|
|
coordinate used to place a glyph outline point, for all the rendered
|
|
glyphs.
|
|
It is a positive value, due to the grid's orientation with the Y axis
|
|
upwards.
|
|
|
|
@item max_glyph_d, descent
|
|
the maximum distance from the baseline to the lowest grid coordinate
|
|
used to place a glyph outline point, for all the rendered glyphs.
|
|
This is a negative value, due to the grid's orientation, with the Y axis
|
|
upwards.
|
|
|
|
@item max_glyph_h
|
|
maximum glyph height, that is the maximum height for all the glyphs
|
|
contained in the rendered text, it is equivalent to @var{ascent} -
|
|
@var{descent}.
|
|
|
|
@item max_glyph_w
|
|
maximum glyph width, that is the maximum width for all the glyphs
|
|
contained in the rendered text
|
|
|
|
@item n
|
|
the number of input frame, starting from 0
|
|
|
|
@item rand(min, max)
|
|
return a random number included between @var{min} and @var{max}
|
|
|
|
@item sar
|
|
input sample aspect ratio
|
|
|
|
@item t
|
|
timestamp expressed in seconds, NAN if the input timestamp is unknown
|
|
|
|
@item text_h, th
|
|
the height of the rendered text
|
|
|
|
@item text_w, tw
|
|
the width of the rendered text
|
|
|
|
@item x, y
|
|
the x and y offset coordinates where the text is drawn.
|
|
|
|
These parameters allow the @var{x} and @var{y} expressions to refer
|
|
each other, so you can for example specify @code{y=x/dar}.
|
|
@end table
|
|
|
|
If libavfilter was built with @code{--enable-fontconfig}, then
|
|
@option{fontfile} can be a fontconfig pattern or omitted.
|
|
|
|
@anchor{drawtext_expansion}
|
|
@subsection Text expansion
|
|
|
|
If @option{expansion} is set to @code{strftime} (which is the default for
|
|
now), the filter recognizes strftime() sequences in the provided text and
|
|
expands them accordingly. Check the documentation of strftime(). This
|
|
feature is deprecated.
|
|
|
|
If @option{expansion} is set to @code{none}, the text is printed verbatim.
|
|
|
|
If @option{expansion} is set to @code{normal} (which will be the default),
|
|
the following expansion mechanism is used.
|
|
|
|
The backslash character '\', followed by any character, always expands to
|
|
the second character.
|
|
|
|
Sequence of the form @code{%@{...@}} are expanded. The text between the
|
|
braces is a function name, possibly followed by arguments separated by ':'.
|
|
If the arguments contain special characters or delimiters (':' or '@}'),
|
|
they should be escaped.
|
|
|
|
Note that they probably must also be escaped as the value for the
|
|
@option{text} option in the filter argument string and as the filter
|
|
argument in the filter graph description, and possibly also for the shell,
|
|
that makes up to four levels of escaping; using a text file avoids these
|
|
problems.
|
|
|
|
The following functions are available:
|
|
|
|
@table @command
|
|
|
|
@item gmtime
|
|
The time at which the filter is running, expressed in UTC.
|
|
It can accept an argument: a strftime() format string.
|
|
|
|
@item localtime
|
|
The time at which the filter is running, expressed in the local time zone.
|
|
It can accept an argument: a strftime() format string.
|
|
|
|
@item pts
|
|
The timestamp of the current frame, in seconds, with microsecond accuracy.
|
|
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
Some examples follow.
|
|
|
|
@itemize
|
|
|
|
@item
|
|
Draw "Test Text" with font FreeSerif, using the default values for the
|
|
optional parameters.
|
|
|
|
@example
|
|
drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
|
|
@end example
|
|
|
|
@item
|
|
Draw 'Test Text' with font FreeSerif of size 24 at position x=100
|
|
and y=50 (counting from the top-left corner of the screen), text is
|
|
yellow with a red box around it. Both the text and the box have an
|
|
opacity of 20%.
|
|
|
|
@example
|
|
drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
|
|
x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
|
|
@end example
|
|
|
|
Note that the double quotes are not necessary if spaces are not used
|
|
within the parameter list.
|
|
|
|
@item
|
|
Show the text at the center of the video frame:
|
|
@example
|
|
drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
|
|
@end example
|
|
|
|
@item
|
|
Show a text line sliding from right to left in the last row of the video
|
|
frame. The file @file{LONG_LINE} is assumed to contain a single line
|
|
with no newlines.
|
|
@example
|
|
drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
|
|
@end example
|
|
|
|
@item
|
|
Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
|
|
@example
|
|
drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
|
|
@end example
|
|
|
|
@item
|
|
Draw a single green letter "g", at the center of the input video.
|
|
The glyph baseline is placed at half screen height.
|
|
@example
|
|
drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
|
|
@end example
|
|
|
|
@item
|
|
Show text for 1 second every 3 seconds:
|
|
@example
|
|
drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:draw=lt(mod(t\,3)\,1):text='blink'"
|
|
@end example
|
|
|
|
@item
|
|
Use fontconfig to set the font. Note that the colons need to be escaped.
|
|
@example
|
|
drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
|
|
@end example
|
|
|
|
@item
|
|
Print the date of a real-time encoding (see strftime(3)):
|
|
@example
|
|
drawtext='fontfile=FreeSans.ttf:expansion=normal:text=%@{localtime:%a %b %d %Y@}'
|
|
@end example
|
|
|
|
@end itemize
|
|
|
|
For more information about libfreetype, check:
|
|
@url{http://www.freetype.org/}.
|
|
|
|
For more information about fontconfig, check:
|
|
@url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
|
|
|
|
@section edgedetect
|
|
|
|
Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
|
|
|
|
This filter accepts the following optional named parameters:
|
|
|
|
@table @option
|
|
@item low, high
|
|
Set low and high threshold values used by the Canny thresholding
|
|
algorithm.
|
|
|
|
The high threshold selects the "strong" edge pixels, which are then
|
|
connected through 8-connectivity with the "weak" edge pixels selected
|
|
by the low threshold.
|
|
|
|
@var{low} and @var{high} threshold values must be choosen in the range
|
|
[0,1], and @var{low} should be lesser or equal to @var{high}.
|
|
|
|
Default value for @var{low} is @code{20/255}, and default value for @var{high}
|
|
is @code{50/255}.
|
|
@end table
|
|
|
|
Example:
|
|
@example
|
|
edgedetect=low=0.1:high=0.4
|
|
@end example
|
|
|
|
@section fade
|
|
|
|
Apply fade-in/out effect to input video.
|
|
|
|
It accepts the parameters:
|
|
@var{type}:@var{start_frame}:@var{nb_frames}[:@var{options}]
|
|
|
|
@var{type} specifies if the effect type, can be either "in" for
|
|
fade-in, or "out" for a fade-out effect.
|
|
|
|
@var{start_frame} specifies the number of the start frame for starting
|
|
to apply the fade effect.
|
|
|
|
@var{nb_frames} specifies the number of frames for which the fade
|
|
effect has to last. At the end of the fade-in effect the output video
|
|
will have the same intensity as the input video, at the end of the
|
|
fade-out transition the output video will be completely black.
|
|
|
|
@var{options} is an optional sequence of @var{key}=@var{value} pairs,
|
|
separated by ":". The description of the accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item type, t
|
|
See @var{type}.
|
|
|
|
@item start_frame, s
|
|
See @var{start_frame}.
|
|
|
|
@item nb_frames, n
|
|
See @var{nb_frames}.
|
|
|
|
@item alpha
|
|
If set to 1, fade only alpha channel, if one exists on the input.
|
|
Default value is 0.
|
|
@end table
|
|
|
|
A few usage examples follow, usable too as test scenarios.
|
|
@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
|
|
|
|
# fade in alpha over first 25 frames of video
|
|
fade=in:0:25:alpha=1
|
|
@end example
|
|
|
|
@section field
|
|
|
|
Extract a single field from an interlaced image using stride
|
|
arithmetic to avoid wasting CPU time. The output frames are marked as
|
|
non-interlaced.
|
|
|
|
This filter accepts the following named options:
|
|
@table @option
|
|
@item type
|
|
Specify whether to extract the top (if the value is @code{0} or
|
|
@code{top}) or the bottom field (if the value is @code{1} or
|
|
@code{bottom}).
|
|
@end table
|
|
|
|
If the option key is not specified, the first value sets the @var{type}
|
|
option. For example:
|
|
@example
|
|
field=bottom
|
|
@end example
|
|
|
|
is equivalent to:
|
|
@example
|
|
field=type=bottom
|
|
@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
|
|
|
|
@section fps
|
|
|
|
Convert the video to specified constant framerate by duplicating or dropping
|
|
frames as necessary.
|
|
|
|
This filter accepts the following named parameters:
|
|
@table @option
|
|
|
|
@item fps
|
|
Desired output framerate.
|
|
|
|
@item round
|
|
Rounding method. The default is @code{near}.
|
|
|
|
@end table
|
|
|
|
@section framestep
|
|
|
|
Select one frame every N.
|
|
|
|
This filter accepts in input a string representing a positive
|
|
integer. Default argument is @code{1}.
|
|
|
|
@anchor{frei0r}
|
|
@section frei0r
|
|
|
|
Apply a frei0r effect to the input video.
|
|
|
|
To enable compilation of this filter you need to install the frei0r
|
|
header and configure FFmpeg with @code{--enable-frei0r}.
|
|
|
|
The filter supports the syntax:
|
|
@example
|
|
@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
|
|
@end example
|
|
|
|
@var{filter_name} is the name of 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 (or
|
|
semicolon on Windows platforms) 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:
|
|
|
|
@itemize
|
|
@item
|
|
Apply the distort0r effect, set the first two double parameters:
|
|
@example
|
|
frei0r=distort0r:0.5:0.01
|
|
@end example
|
|
|
|
@item
|
|
Apply the colordistance effect, take a color as first parameter:
|
|
@example
|
|
frei0r=colordistance:0.2/0.3/0.4
|
|
frei0r=colordistance:violet
|
|
frei0r=colordistance:0x112233
|
|
@end example
|
|
|
|
@item
|
|
Apply the perspective effect, specify the top left and top right image
|
|
positions:
|
|
@example
|
|
frei0r=perspective:0.2/0.2:0.8/0.2
|
|
@end example
|
|
@end itemize
|
|
|
|
For more information see:
|
|
@url{http://frei0r.dyne.org}
|
|
|
|
@section geq
|
|
|
|
The filter takes one, two or three equations as parameter, separated by ':'.
|
|
The first equation is mandatory and applies to the luma plane. The two
|
|
following are respectively for chroma blue and chroma red planes.
|
|
|
|
The filter syntax allows named parameters:
|
|
|
|
@table @option
|
|
@item lum_expr
|
|
the luminance expression
|
|
@item cb_expr
|
|
the chrominance blue expression
|
|
@item cr_expr
|
|
the chrominance red expression
|
|
@end table
|
|
|
|
If one of the chrominance expression is not defined, it falls back on the other
|
|
one. If none of them are specified, they will evaluate the luminance
|
|
expression.
|
|
|
|
The expressions can use the following variables and functions:
|
|
|
|
@table @option
|
|
@item N
|
|
The sequential number of the filtered frame, starting from @code{0}.
|
|
|
|
@item X, Y
|
|
The coordinates of the current sample.
|
|
|
|
@item W, H
|
|
The width and height of the image.
|
|
|
|
@item SW, SH
|
|
Width and height scale depending on the currently filtered plane. It is the
|
|
ratio between the corresponding luma plane number of pixels and the current
|
|
plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
|
|
@code{0.5,0.5} for chroma planes.
|
|
|
|
@item p(x, y)
|
|
Return the value of the pixel at location (@var{x},@var{y}) of the current
|
|
plane.
|
|
|
|
@item lum(x, y)
|
|
Return the value of the pixel at location (@var{x},@var{y}) of the luminance
|
|
plane.
|
|
|
|
@item cb(x, y)
|
|
Return the value of the pixel at location (@var{x},@var{y}) of the
|
|
blue-difference chroma plane.
|
|
|
|
@item cr(x, y)
|
|
Return the value of the pixel at location (@var{x},@var{y}) of the
|
|
red-difference chroma plane.
|
|
@end table
|
|
|
|
For functions, if @var{x} and @var{y} are outside the area, the value will be
|
|
automatically clipped to the closer edge.
|
|
|
|
Some examples follow:
|
|
|
|
@itemize
|
|
@item
|
|
Flip the image horizontally:
|
|
@example
|
|
geq=p(W-X\,Y)
|
|
@end example
|
|
|
|
@item
|
|
Generate a fancy enigmatic moving light:
|
|
@example
|
|
nullsrc=s=256x256,geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128
|
|
@end example
|
|
@end itemize
|
|
|
|
@section gradfun
|
|
|
|
Fix the banding artifacts that are sometimes introduced into nearly flat
|
|
regions by truncation to 8bit color depth.
|
|
Interpolate the gradients that should go where the bands are, and
|
|
dither them.
|
|
|
|
This filter is designed for playback only. Do not use it prior to
|
|
lossy compression, because compression tends to lose the dither and
|
|
bring back the bands.
|
|
|
|
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 input video with @command{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 hue
|
|
|
|
Modify the hue and/or the saturation of the input.
|
|
|
|
This filter accepts the following optional named options:
|
|
|
|
@table @option
|
|
@item h
|
|
Specify the hue angle as a number of degrees. It accepts a float
|
|
number or an expression, and defaults to 0.0.
|
|
|
|
@item H
|
|
Specify the hue angle as a number of degrees. It accepts a float
|
|
number or an expression, and defaults to 0.0.
|
|
|
|
@item s
|
|
Specify the saturation in the [-10,10] range. It accepts a float number and
|
|
defaults to 1.0.
|
|
@end table
|
|
|
|
The @var{h}, @var{H} and @var{s} parameters are expressions containing the
|
|
following constants:
|
|
|
|
@table @option
|
|
@item n
|
|
frame count of the input frame starting from 0
|
|
|
|
@item pts
|
|
presentation timestamp of the input frame expressed in time base units
|
|
|
|
@item r
|
|
frame rate of the input video, NAN if the input frame rate is unknown
|
|
|
|
@item t
|
|
timestamp expressed in seconds, NAN if the input timestamp is unknown
|
|
|
|
@item tb
|
|
time base of the input video
|
|
@end table
|
|
|
|
The options can also be set using the syntax: @var{hue}:@var{saturation}
|
|
|
|
In this case @var{hue} is expressed in degrees.
|
|
|
|
Some examples follow:
|
|
@itemize
|
|
@item
|
|
Set the hue to 90 degrees and the saturation to 1.0:
|
|
@example
|
|
hue=h=90:s=1
|
|
@end example
|
|
|
|
@item
|
|
Same command but expressing the hue in radians:
|
|
@example
|
|
hue=H=PI/2:s=1
|
|
@end example
|
|
|
|
@item
|
|
Same command without named options, hue must be expressed in degrees:
|
|
@example
|
|
hue=90:1
|
|
@end example
|
|
|
|
@item
|
|
Note that "h:s" syntax does not support expressions for the values of
|
|
h and s, so the following example will issue an error:
|
|
@example
|
|
hue=PI/2:1
|
|
@end example
|
|
|
|
@item
|
|
Rotate hue and make the saturation swing between 0
|
|
and 2 over a period of 1 second:
|
|
@example
|
|
hue="H=2*PI*t: s=sin(2*PI*t)+1"
|
|
@end example
|
|
|
|
@item
|
|
Apply a 3 seconds saturation fade-in effect starting at 0:
|
|
@example
|
|
hue="s=min(t/3\,1)"
|
|
@end example
|
|
|
|
The general fade-in expression can be written as:
|
|
@example
|
|
hue="s=min(0\, max((t-START)/DURATION\, 1))"
|
|
@end example
|
|
|
|
@item
|
|
Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
|
|
@example
|
|
hue="s=max(0\, min(1\, (8-t)/3))"
|
|
@end example
|
|
|
|
The general fade-out expression can be written as:
|
|
@example
|
|
hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
|
|
@end example
|
|
|
|
@end itemize
|
|
|
|
@subsection Commands
|
|
|
|
This filter supports the following command:
|
|
@table @option
|
|
@item reinit
|
|
Modify the hue and/or the saturation of the input video.
|
|
The command accepts the same named options and syntax than when calling the
|
|
filter from the command-line.
|
|
|
|
If a parameter is omitted, it is kept at its current value.
|
|
@end table
|
|
|
|
@section idet
|
|
|
|
Interlaceing detect filter. This filter tries to detect if the input is
|
|
interlaced or progressive. Top or bottom field first.
|
|
|
|
@section lut, lutrgb, lutyuv
|
|
|
|
Compute a look-up table for binding each pixel component input value
|
|
to an output value, and apply it to input video.
|
|
|
|
@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
|
|
to an RGB input video.
|
|
|
|
These filters accept in input a ":"-separated list of options, which
|
|
specify the expressions used for computing the lookup table for the
|
|
corresponding pixel component values.
|
|
|
|
The @var{lut} filter requires either YUV or RGB pixel formats in
|
|
input, and accepts the options:
|
|
@table @option
|
|
@item @var{c0} (first pixel component)
|
|
@item @var{c1} (second pixel component)
|
|
@item @var{c2} (third pixel component)
|
|
@item @var{c3} (fourth pixel component, corresponds to the alpha component)
|
|
@end table
|
|
|
|
The exact component associated to each option depends on the format in
|
|
input.
|
|
|
|
The @var{lutrgb} filter requires RGB pixel formats in input, and
|
|
accepts the options:
|
|
@table @option
|
|
@item @var{r} (red component)
|
|
@item @var{g} (green component)
|
|
@item @var{b} (blue component)
|
|
@item @var{a} (alpha component)
|
|
@end table
|
|
|
|
The @var{lutyuv} filter requires YUV pixel formats in input, and
|
|
accepts the options:
|
|
@table @option
|
|
@item @var{y} (Y/luminance component)
|
|
@item @var{u} (U/Cb component)
|
|
@item @var{v} (V/Cr component)
|
|
@item @var{a} (alpha component)
|
|
@end table
|
|
|
|
The expressions can contain the following constants and functions:
|
|
|
|
@table @option
|
|
@item w, h
|
|
the input width and height
|
|
|
|
@item val
|
|
input value for the pixel component
|
|
|
|
@item clipval
|
|
the input value clipped in the @var{minval}-@var{maxval} range
|
|
|
|
@item maxval
|
|
maximum value for the pixel component
|
|
|
|
@item minval
|
|
minimum value for the pixel component
|
|
|
|
@item negval
|
|
the negated value for the pixel component value clipped in the
|
|
@var{minval}-@var{maxval} range , it corresponds to the expression
|
|
"maxval-clipval+minval"
|
|
|
|
@item clip(val)
|
|
the computed value in @var{val} clipped in the
|
|
@var{minval}-@var{maxval} range
|
|
|
|
@item gammaval(gamma)
|
|
the computed gamma correction value of the pixel component value
|
|
clipped in the @var{minval}-@var{maxval} range, corresponds to the
|
|
expression
|
|
"pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
|
|
|
|
@end table
|
|
|
|
All expressions default to "val".
|
|
|
|
Some examples follow:
|
|
@example
|
|
# negate input video
|
|
lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
|
|
lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
|
|
|
|
# the above is the same as
|
|
lutrgb="r=negval:g=negval:b=negval"
|
|
lutyuv="y=negval:u=negval:v=negval"
|
|
|
|
# negate luminance
|
|
lutyuv=y=negval
|
|
|
|
# remove chroma components, turns the video into a graytone image
|
|
lutyuv="u=128:v=128"
|
|
|
|
# apply a luma burning effect
|
|
lutyuv="y=2*val"
|
|
|
|
# remove green and blue components
|
|
lutrgb="g=0:b=0"
|
|
|
|
# set a constant alpha channel value on input
|
|
format=rgba,lutrgb=a="maxval-minval/2"
|
|
|
|
# correct luminance gamma by a 0.5 factor
|
|
lutyuv=y=gammaval(0.5)
|
|
@end example
|
|
|
|
@section mp
|
|
|
|
Apply an MPlayer filter to the input video.
|
|
|
|
This filter provides a wrapper around most of the filters of
|
|
MPlayer/MEncoder.
|
|
|
|
This wrapper is considered experimental. Some of the wrapped filters
|
|
may not work properly and we may drop support for them, as they will
|
|
be implemented natively into FFmpeg. Thus you should avoid
|
|
depending on them when writing portable scripts.
|
|
|
|
The filters accepts the parameters:
|
|
@var{filter_name}[:=]@var{filter_params}
|
|
|
|
@var{filter_name} is the name of a supported MPlayer filter,
|
|
@var{filter_params} is a string containing the parameters accepted by
|
|
the named filter.
|
|
|
|
The list of the currently supported filters follows:
|
|
@table @var
|
|
@item denoise3d
|
|
@item detc
|
|
@item dint
|
|
@item divtc
|
|
@item down3dright
|
|
@item dsize
|
|
@item eq2
|
|
@item eq
|
|
@item fil
|
|
@item fspp
|
|
@item harddup
|
|
@item il
|
|
@item ilpack
|
|
@item ivtc
|
|
@item kerndeint
|
|
@item mcdeint
|
|
@item noise
|
|
@item ow
|
|
@item perspective
|
|
@item phase
|
|
@item pp7
|
|
@item pullup
|
|
@item qp
|
|
@item sab
|
|
@item softpulldown
|
|
@item softskip
|
|
@item spp
|
|
@item telecine
|
|
@item tinterlace
|
|
@item unsharp
|
|
@item uspp
|
|
@end table
|
|
|
|
The parameter syntax and behavior for the listed filters are the same
|
|
of the corresponding MPlayer filters. For detailed instructions check
|
|
the "VIDEO FILTERS" section in the MPlayer manual.
|
|
|
|
Some examples follow:
|
|
@itemize
|
|
@item
|
|
Adjust gamma, brightness, contrast:
|
|
@example
|
|
mp=eq2=1.0:2:0.5
|
|
@end example
|
|
|
|
@item
|
|
Add temporal noise to input video:
|
|
@example
|
|
mp=noise=20t
|
|
@end example
|
|
@end itemize
|
|
|
|
See also mplayer(1), @url{http://www.mplayerhq.hu/}.
|
|
|
|
@section negate
|
|
|
|
Negate input video.
|
|
|
|
This filter accepts an integer in input, if non-zero it negates the
|
|
alpha component (if available). The default value in input is 0.
|
|
|
|
@section noformat
|
|
|
|
Force libavfilter not to use any of the specified pixel formats for the
|
|
input to the next filter.
|
|
|
|
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 FFmpeg with @code{--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
|
|
information:
|
|
@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
|
|
|
|
Follows the list of supported libopencv filters.
|
|
|
|
@anchor{dilate}
|
|
@subsection dilate
|
|
|
|
Dilate an image by using a specific structuring element.
|
|
This filter corresponds to the libopencv function @code{cvDilate}.
|
|
|
|
It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
|
|
|
|
@var{struct_el} represents a structuring element, and has the syntax:
|
|
@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
|
|
|
|
@var{cols} and @var{rows} represent the number of columns and rows of
|
|
the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
|
|
point, and @var{shape} the shape for the structuring element, and
|
|
can be one of the values "rect", "cross", "ellipse", "custom".
|
|
|
|
If the value for @var{shape} is "custom", it must be followed by a
|
|
string of the form "=@var{filename}". The file with name
|
|
@var{filename} is assumed to represent a binary image, with each
|
|
printable character corresponding to a bright pixel. When a custom
|
|
@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
|
|
or columns and rows of the read file are assumed instead.
|
|
|
|
The default value for @var{struct_el} is "3x3+0x0/rect".
|
|
|
|
@var{nb_iterations} specifies the number of times the transform is
|
|
applied to the image, and defaults to 1.
|
|
|
|
Follow some example:
|
|
@example
|
|
# use the default values
|
|
ocv=dilate
|
|
|
|
# dilate using a structuring element with a 5x5 cross, iterate two times
|
|
ocv=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 syntax and semantics as the @ref{dilate} filter.
|
|
|
|
@subsection smooth
|
|
|
|
Smooth the input video.
|
|
|
|
The filter takes the following parameters:
|
|
@var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
|
|
|
|
@var{type} is the type of smooth filter to apply, and can be one of
|
|
the following values: "blur", "blur_no_scale", "median", "gaussian",
|
|
"bilateral". The default value is "gaussian".
|
|
|
|
@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
|
|
parameters whose meanings depend on smooth type. @var{param1} and
|
|
@var{param2} accept integer positive values or 0, @var{param3} and
|
|
@var{param4} accept float values.
|
|
|
|
The default value for @var{param1} is 3, the default value for the
|
|
other parameters is 0.
|
|
|
|
These parameters correspond to the parameters assigned to the
|
|
libopencv function @code{cvSmooth}.
|
|
|
|
@anchor{overlay}
|
|
@section overlay
|
|
|
|
Overlay one video on top of another.
|
|
|
|
It takes two inputs and one output, the first input is the "main"
|
|
video on which the second input is overlayed.
|
|
|
|
It accepts the parameters: @var{x}:@var{y}[:@var{options}].
|
|
|
|
@var{x} is the x coordinate of the overlayed video on the main video,
|
|
@var{y} is the y coordinate. @var{x} and @var{y} 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
|
|
|
|
@var{options} is an optional list of @var{key}=@var{value} pairs,
|
|
separated by ":".
|
|
|
|
The description of the accepted options follows.
|
|
|
|
@table @option
|
|
@item rgb
|
|
If set to 1, force the filter to accept inputs in the RGB
|
|
color space. Default value is 0.
|
|
@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
|
|
ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
|
|
|
|
# insert 2 different transparent PNG logos (second logo on bottom
|
|
# right corner):
|
|
ffmpeg -i input -i logo1 -i logo2 -filter_complex
|
|
'overlay=10:H-h-10,overlay=W-w-10:H-h-10' output
|
|
|
|
# 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]
|
|
|
|
# play an original video and a filtered version (here with the deshake filter)
|
|
# side by side
|
|
ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
|
|
|
|
# the previous example is the same as:
|
|
ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
|
|
@end example
|
|
|
|
You can chain together 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 in_w, in_h
|
|
the input video width and height
|
|
|
|
@item iw, ih
|
|
same as @var{in_w} and @var{in_h}
|
|
|
|
@item out_w, out_h
|
|
the output width and height, that is the size of the padded area as
|
|
specified by the @var{width} and @var{height} expressions
|
|
|
|
@item 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
|
|
same as @var{iw} / @var{ih}
|
|
|
|
@item sar
|
|
input sample aspect ratio
|
|
|
|
@item dar
|
|
input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
|
|
|
|
@item hsub, 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 vice versa.
|
|
|
|
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 vice versa.
|
|
|
|
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
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Add paddings with color "violet" to the input video. Output video
|
|
size is 640x480, the top-left corner of the input video is placed at
|
|
column 0, row 40:
|
|
@example
|
|
pad=640:480:0:40:violet
|
|
@end example
|
|
|
|
@item
|
|
Pad the input to get an output with dimensions increased by 3/2,
|
|
and put the input video at the center of the padded area:
|
|
@example
|
|
pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
|
|
@end example
|
|
|
|
@item
|
|
Pad the input to get a squared output with size equal to the maximum
|
|
value between the input width and height, and put the input video at
|
|
the center of the padded area:
|
|
@example
|
|
pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
|
|
@end example
|
|
|
|
@item
|
|
Pad the input to get a final w/h ratio of 16:9:
|
|
@example
|
|
pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
|
|
@end example
|
|
|
|
@item
|
|
In case of anamorphic video, in order to set the output display aspect
|
|
correctly, it is necessary to use @var{sar} in the expression,
|
|
according to the relation:
|
|
@example
|
|
(ih * X / ih) * sar = output_dar
|
|
X = output_dar / sar
|
|
@end example
|
|
|
|
Thus the previous example needs to be modified to:
|
|
@example
|
|
pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
|
|
@end example
|
|
|
|
@item
|
|
Double output size and put the input video in the bottom-right
|
|
corner of the output padded area:
|
|
@example
|
|
pad="2*iw:2*ih:ow-iw:oh-ih"
|
|
@end example
|
|
@end itemize
|
|
|
|
@section 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 removelogo
|
|
|
|
Suppress a TV station logo, using an image file to determine which
|
|
pixels comprise the logo. It works by filling in the pixels that
|
|
comprise the logo with neighboring pixels.
|
|
|
|
This filter requires one argument which specifies the filter bitmap
|
|
file, which can be any image format supported by libavformat. The
|
|
width and height of the image file must match those of the video
|
|
stream being processed.
|
|
|
|
Pixels in the provided bitmap image with a value of zero are not
|
|
considered part of the logo, non-zero pixels are considered part of
|
|
the logo. If you use white (255) for the logo and black (0) for the
|
|
rest, you will be safe. For making the filter bitmap, it is
|
|
recommended to take a screen capture of a black frame with the logo
|
|
visible, and then using a threshold filter followed by the erode
|
|
filter once or twice.
|
|
|
|
If needed, little splotches can be fixed manually. Remember that if
|
|
logo pixels are not covered, the filter quality will be much
|
|
reduced. Marking too many pixels as part of the logo does not hurt as
|
|
much, but it will increase the amount of blurring needed to cover over
|
|
the image and will destroy more information than necessary, and extra
|
|
pixels will slow things down on a large logo.
|
|
|
|
@section scale
|
|
|
|
Scale (resize) the input video, using the libswscale library.
|
|
|
|
The scale filter forces the output display aspect ratio to be the same
|
|
of the input, by changing the output sample aspect ratio.
|
|
|
|
This filter accepts a list of named options in the form of
|
|
@var{key}=@var{value} pairs separated by ":". If the key for the first
|
|
two options is not specified, the assumed keys for the first two
|
|
values are @code{w} and @code{h}. If the first option has no key and
|
|
can be interpreted like a video size specification, it will be used
|
|
to set the video size.
|
|
|
|
A description of the accepted options follows.
|
|
|
|
@table @option
|
|
@item width, w
|
|
Set the video width expression, default value is @code{iw}. See below
|
|
for the list of accepted constants.
|
|
|
|
@item height, h
|
|
Set the video heiht expression, default value is @code{ih}.
|
|
See below for the list of accepted constants.
|
|
|
|
@item interl
|
|
Set the interlacing. It accepts the following values:
|
|
|
|
@table @option
|
|
@item 1
|
|
force interlaced aware scaling
|
|
|
|
@item 0
|
|
do not apply interlaced scaling
|
|
|
|
@item -1
|
|
select interlaced aware scaling depending on whether the source frames
|
|
are flagged as interlaced or not
|
|
@end table
|
|
|
|
Default value is @code{0}.
|
|
|
|
@item flags
|
|
Set libswscale scaling flags. If not explictly specified the filter
|
|
applies a bilinear scaling algorithm.
|
|
|
|
@item size, s
|
|
Set the video size, the value must be a valid abbreviation or in the
|
|
form @var{width}x@var{height}.
|
|
@end table
|
|
|
|
The values of the @var{w} and @var{h} options are expressions
|
|
containing the following constants:
|
|
|
|
@table @option
|
|
@item in_w, in_h
|
|
the input width and height
|
|
|
|
@item iw, ih
|
|
same as @var{in_w} and @var{in_h}
|
|
|
|
@item out_w, out_h
|
|
the output (cropped) width and height
|
|
|
|
@item ow, oh
|
|
same as @var{out_w} and @var{out_h}
|
|
|
|
@item a
|
|
same as @var{iw} / @var{ih}
|
|
|
|
@item sar
|
|
input sample aspect ratio
|
|
|
|
@item dar
|
|
input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
|
|
|
|
@item hsub, 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.
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Scale the input video to a size of 200x100:
|
|
@example
|
|
scale=200:100
|
|
@end example
|
|
|
|
This is equivalent to:
|
|
@example
|
|
scale=w=200:h=100
|
|
@end example
|
|
|
|
or:
|
|
@example
|
|
scale=200x100
|
|
@end example
|
|
|
|
@item
|
|
Specify a size abbreviation for the output size:
|
|
@example
|
|
scale=qcif
|
|
@end example
|
|
|
|
which can also be written as:
|
|
@example
|
|
scale=size=qcif
|
|
@end example
|
|
|
|
@item
|
|
Scale the input to 2x:
|
|
@example
|
|
scale=2*iw:2*ih
|
|
@end example
|
|
|
|
@item
|
|
The above is the same as:
|
|
@example
|
|
scale=2*in_w:2*in_h
|
|
@end example
|
|
|
|
@item
|
|
Scale the input to 2x with forced interlaced scaling:
|
|
@example
|
|
scale=2*iw:2*ih:interl=1
|
|
@end example
|
|
|
|
@item
|
|
Scale the input to half size:
|
|
@example
|
|
scale=iw/2:ih/2
|
|
@end example
|
|
|
|
@item
|
|
Increase the width, and set the height to the same size:
|
|
@example
|
|
scale=3/2*iw:ow
|
|
@end example
|
|
|
|
@item
|
|
Seek for Greek harmony:
|
|
@example
|
|
scale=iw:1/PHI*iw
|
|
scale=ih*PHI:ih
|
|
@end example
|
|
|
|
@item
|
|
Increase the height, and set the width to 3/2 of the height:
|
|
@example
|
|
scale=3/2*oh:3/5*ih
|
|
@end example
|
|
|
|
@item
|
|
Increase the size, but make the size a multiple of the chroma:
|
|
@example
|
|
scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
|
|
@end example
|
|
|
|
@item
|
|
Increase the width to a maximum of 500 pixels, keep the same input
|
|
aspect ratio:
|
|
@example
|
|
scale='min(500\, iw*3/2):-1'
|
|
@end example
|
|
@end itemize
|
|
|
|
@section select
|
|
Select frames to pass in output.
|
|
|
|
It accepts in input an expression, which is evaluated for each input
|
|
frame. If the expression is evaluated to a non-zero value, the frame
|
|
is selected and passed to the output, otherwise it is discarded.
|
|
|
|
The expression can contain the following constants:
|
|
|
|
@table @option
|
|
@item n
|
|
the sequential number of the filtered frame, starting from 0
|
|
|
|
@item selected_n
|
|
the sequential number of the selected frame, starting from 0
|
|
|
|
@item prev_selected_n
|
|
the sequential number of the last selected frame, NAN if undefined
|
|
|
|
@item TB
|
|
timebase of the input timestamps
|
|
|
|
@item pts
|
|
the PTS (Presentation TimeStamp) of the filtered video frame,
|
|
expressed in @var{TB} units, NAN if undefined
|
|
|
|
@item t
|
|
the PTS (Presentation TimeStamp) of the filtered video frame,
|
|
expressed in seconds, NAN if undefined
|
|
|
|
@item prev_pts
|
|
the PTS of the previously filtered video frame, NAN if undefined
|
|
|
|
@item prev_selected_pts
|
|
the PTS of the last previously filtered video frame, NAN if undefined
|
|
|
|
@item prev_selected_t
|
|
the PTS of the last previously selected video frame, NAN if undefined
|
|
|
|
@item start_pts
|
|
the PTS of the first video frame in the video, NAN if undefined
|
|
|
|
@item start_t
|
|
the time of the first video frame in the video, NAN if undefined
|
|
|
|
@item pict_type
|
|
the type of the filtered frame, can assume one of the following
|
|
values:
|
|
@table @option
|
|
@item I
|
|
@item P
|
|
@item B
|
|
@item S
|
|
@item SI
|
|
@item SP
|
|
@item BI
|
|
@end table
|
|
|
|
@item interlace_type
|
|
the frame interlace type, can assume one of the following values:
|
|
@table @option
|
|
@item PROGRESSIVE
|
|
the frame is progressive (not interlaced)
|
|
@item TOPFIRST
|
|
the frame is top-field-first
|
|
@item BOTTOMFIRST
|
|
the frame is bottom-field-first
|
|
@end table
|
|
|
|
@item key
|
|
1 if the filtered frame is a key-frame, 0 otherwise
|
|
|
|
@item pos
|
|
the position in the file of the filtered frame, -1 if the information
|
|
is not available (e.g. for synthetic video)
|
|
|
|
@item scene
|
|
value between 0 and 1 to indicate a new scene; a low value reflects a low
|
|
probability for the current frame to introduce a new scene, while a higher
|
|
value means the current frame is more likely to be one (see the example below)
|
|
|
|
@end table
|
|
|
|
The default value of the select expression is "1".
|
|
|
|
Some examples follow:
|
|
|
|
@example
|
|
# select all frames in input
|
|
select
|
|
|
|
# the above is the same as:
|
|
select=1
|
|
|
|
# skip all frames:
|
|
select=0
|
|
|
|
# select only I-frames
|
|
select='eq(pict_type\,I)'
|
|
|
|
# select one frame every 100
|
|
select='not(mod(n\,100))'
|
|
|
|
# select only frames contained in the 10-20 time interval
|
|
select='gte(t\,10)*lte(t\,20)'
|
|
|
|
# select only I frames contained in the 10-20 time interval
|
|
select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
|
|
|
|
# select frames with a minimum distance of 10 seconds
|
|
select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
|
|
@end example
|
|
|
|
Complete example to create a mosaic of the first scenes:
|
|
|
|
@example
|
|
ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
|
|
@end example
|
|
|
|
Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
|
|
choice.
|
|
|
|
@section setdar, setsar
|
|
|
|
The @code{setdar} filter sets the Display Aspect Ratio for the filter
|
|
output video.
|
|
|
|
This is done by changing the specified Sample (aka Pixel) Aspect
|
|
Ratio, according to the following equation:
|
|
@example
|
|
@var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
|
|
@end example
|
|
|
|
Keep in mind that the @code{setdar} filter does not modify the pixel
|
|
dimensions of the video frame. Also the display aspect ratio set by
|
|
this filter may be changed by later filters in the filterchain,
|
|
e.g. in case of scaling or if another "setdar" or a "setsar" filter is
|
|
applied.
|
|
|
|
The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
|
|
the filter output video.
|
|
|
|
Note that as a consequence of the application of this filter, the
|
|
output display aspect ratio will change according to the equation
|
|
above.
|
|
|
|
Keep in mind that the sample aspect ratio set by the @code{setsar}
|
|
filter may be changed by later filters in the filterchain, e.g. if
|
|
another "setsar" or a "setdar" filter is applied.
|
|
|
|
The @code{setdar} and @code{setsar} filters accept a string in the
|
|
form @var{num}:@var{den} expressing an aspect ratio, or the following
|
|
named options, expressed as a sequence of @var{key}=@var{value} pairs,
|
|
separated by ":".
|
|
|
|
@table @option
|
|
@item max
|
|
Set the maximum integer value to use for expressing numerator and
|
|
denominator when reducing the expressed aspect ratio to a rational.
|
|
Default value is @code{100}.
|
|
|
|
@item r, ratio:
|
|
Set the aspect ratio used by the filter.
|
|
|
|
The parameter can be a floating point number string, an expression, or
|
|
a string of the form @var{num}:@var{den}, where @var{num} and
|
|
@var{den} are the numerator and denominator of the aspect ratio. If
|
|
the parameter is not specified, it is assumed the value "0".
|
|
In case the form "@var{num}:@var{den}" the @code{:} character should
|
|
be escaped.
|
|
@end table
|
|
|
|
If the keys are omitted in the named options list, the specifed values
|
|
are assumed to be @var{ratio} and @var{max} in that order.
|
|
|
|
For example to change the display aspect ratio to 16:9, specify:
|
|
@example
|
|
setdar='16:9'
|
|
@end example
|
|
|
|
The example above is equivalent to:
|
|
@example
|
|
setdar=1.77777
|
|
@end example
|
|
|
|
To change the sample aspect ratio to 10:11, specify:
|
|
@example
|
|
setsar='10:11'
|
|
@end example
|
|
|
|
To set a display aspect ratio of 16:9, and specify a maximum integer value of
|
|
1000 in the aspect ratio reduction, use the command:
|
|
@example
|
|
setdar=ratio='16:9':max=1000
|
|
@end example
|
|
|
|
@section setfield
|
|
|
|
Force field for the output video frame.
|
|
|
|
The @code{setfield} filter marks the interlace type field for the
|
|
output frames. It does not change the input frame, but only sets the
|
|
corresponding property, which affects how the frame is treated by
|
|
following filters (e.g. @code{fieldorder} or @code{yadif}).
|
|
|
|
It accepts a string parameter, which can assume the following values:
|
|
@table @samp
|
|
@item auto
|
|
Keep the same field property.
|
|
|
|
@item bff
|
|
Mark the frame as bottom-field-first.
|
|
|
|
@item tff
|
|
Mark the frame as top-field-first.
|
|
|
|
@item prog
|
|
Mark the frame as progressive.
|
|
@end table
|
|
|
|
@section showinfo
|
|
|
|
Show a line containing various information for each input video frame.
|
|
The input video is not modified.
|
|
|
|
The shown line contains a sequence of key/value pairs of the form
|
|
@var{key}:@var{value}.
|
|
|
|
A description of each shown parameter follows:
|
|
|
|
@table @option
|
|
@item n
|
|
sequential number of the input frame, starting from 0
|
|
|
|
@item pts
|
|
Presentation TimeStamp of the input frame, expressed as a number of
|
|
time base units. The time base unit depends on the filter input pad.
|
|
|
|
@item pts_time
|
|
Presentation TimeStamp of the input frame, expressed as a number of
|
|
seconds
|
|
|
|
@item pos
|
|
position of the frame in the input stream, -1 if this information in
|
|
unavailable and/or meaningless (for example in case of synthetic video)
|
|
|
|
@item fmt
|
|
pixel format name
|
|
|
|
@item sar
|
|
sample aspect ratio of the input frame, expressed in the form
|
|
@var{num}/@var{den}
|
|
|
|
@item s
|
|
size of the input frame, expressed in the form
|
|
@var{width}x@var{height}
|
|
|
|
@item i
|
|
interlaced mode ("P" for "progressive", "T" for top field first, "B"
|
|
for bottom field first)
|
|
|
|
@item iskey
|
|
1 if the frame is a key frame, 0 otherwise
|
|
|
|
@item type
|
|
picture type of the input frame ("I" for an I-frame, "P" for a
|
|
P-frame, "B" for a B-frame, "?" for unknown type).
|
|
Check also the documentation of the @code{AVPictureType} enum and of
|
|
the @code{av_get_picture_type_char} function defined in
|
|
@file{libavutil/avutil.h}.
|
|
|
|
@item checksum
|
|
Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
|
|
|
|
@item plane_checksum
|
|
Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
|
|
expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
|
|
@end table
|
|
|
|
@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 smartblur
|
|
|
|
Blur the input video without impacting the outlines.
|
|
|
|
The filter accepts the following parameters:
|
|
@var{luma_radius}:@var{luma_strength}:@var{luma_threshold}[:@var{chroma_radius}:@var{chroma_strength}:@var{chroma_threshold}]
|
|
|
|
Parameters prefixed by @var{luma} indicate that they work on the
|
|
luminance of the pixels whereas parameters prefixed by @var{chroma}
|
|
refer to the chrominance of the pixels.
|
|
|
|
If the chroma parameters are not set, the luma parameters are used for
|
|
either the luminance and the chrominance of the pixels.
|
|
|
|
@var{luma_radius} or @var{chroma_radius} must be a float number in the
|
|
range [0.1,5.0] that specifies the variance of the gaussian filter
|
|
used to blur the image (slower if larger).
|
|
|
|
@var{luma_strength} or @var{chroma_strength} must be a float number in
|
|
the range [-1.0,1.0] that configures the blurring. A value included in
|
|
[0.0,1.0] will blur the image whereas a value included in [-1.0,0.0]
|
|
will sharpen the image.
|
|
|
|
@var{luma_threshold} or @var{chroma_threshold} must be an integer in
|
|
the range [-30,30] that is used as a coefficient to determine whether
|
|
a pixel should be blurred or not. A value of 0 will filter all the
|
|
image, a value included in [0,30] will filter flat areas and a value
|
|
included in [-30,0] will filter edges.
|
|
|
|
@section split
|
|
|
|
Split input video into several identical outputs.
|
|
|
|
The filter accepts a single parameter which specifies the number of outputs. If
|
|
unspecified, it defaults to 2.
|
|
|
|
For example
|
|
@example
|
|
ffmpeg -i INPUT -filter_complex split=5 OUTPUT
|
|
@end example
|
|
will create 5 copies of the input video.
|
|
|
|
For example:
|
|
@example
|
|
[in] split [splitout1][splitout2];
|
|
[splitout1] crop=100:100:0:0 [cropout];
|
|
[splitout2] pad=200:200:100:100 [padout];
|
|
@end example
|
|
|
|
will create two separate outputs from the same input, one cropped and
|
|
one padded.
|
|
|
|
@section super2xsai
|
|
|
|
Scale the input by 2x and smooth using the Super2xSaI (Scale and
|
|
Interpolate) pixel art scaling algorithm.
|
|
|
|
Useful for enlarging pixel art images without reducing sharpness.
|
|
|
|
@section swapuv
|
|
Swap U & V plane.
|
|
|
|
@section thumbnail
|
|
Select the most representative frame in a given sequence of consecutive frames.
|
|
|
|
It accepts as argument the frames batch size to analyze (default @var{N}=100);
|
|
in a set of @var{N} frames, the filter will pick one of them, and then handle
|
|
the next batch of @var{N} frames until the end.
|
|
|
|
Since the filter keeps track of the whole frames sequence, a bigger @var{N}
|
|
value will result in a higher memory usage, so a high value is not recommended.
|
|
|
|
The following example extract one picture each 50 frames:
|
|
@example
|
|
thumbnail=50
|
|
@end example
|
|
|
|
Complete example of a thumbnail creation with @command{ffmpeg}:
|
|
@example
|
|
ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
|
|
@end example
|
|
|
|
@section tile
|
|
|
|
Tile several successive frames together.
|
|
|
|
It accepts a list of options in the form of @var{key}=@var{value} pairs
|
|
separated by ":". A description of the accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item layout
|
|
Set the grid size (i.e. the number of lines and columns) in the form
|
|
"@var{w}x@var{h}".
|
|
|
|
@item margin
|
|
Set the outer border margin in pixels.
|
|
|
|
@item padding
|
|
Set the inner border thickness (i.e. the number of pixels between frames). For
|
|
more advanced padding options (such as having different values for the edges),
|
|
refer to the pad video filter.
|
|
|
|
@item nb_frames
|
|
Set the maximum number of frames to render in the given area. It must be less
|
|
than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
|
|
the area will be used.
|
|
|
|
@end table
|
|
|
|
Alternatively, the options can be specified as a flat string:
|
|
|
|
@var{layout}[:@var{nb_frames}[:@var{margin}[:@var{padding}]]]
|
|
|
|
For example, produce 8×8 PNG tiles of all keyframes (@option{-skip_frame
|
|
nokey}) in a movie:
|
|
@example
|
|
ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
|
|
@end example
|
|
The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
|
|
duplicating each output frame to accomodate the originally detected frame
|
|
rate.
|
|
|
|
Another example to display @code{5} pictures in an area of @code{3x2} frames,
|
|
with @code{7} pixels between them, and @code{2} pixels of initial margin, using
|
|
mixed flat and named options:
|
|
@example
|
|
tile=3x2:nb_frames=5:padding=7:margin=2
|
|
@end example
|
|
|
|
@section tinterlace
|
|
|
|
Perform various types of temporal field interlacing.
|
|
|
|
Frames are counted starting from 1, so the first input frame is
|
|
considered odd.
|
|
|
|
This filter accepts a single parameter specifying the mode. Available
|
|
modes are:
|
|
|
|
@table @samp
|
|
@item merge, 0
|
|
Move odd frames into the upper field, even into the lower field,
|
|
generating a double height frame at half framerate.
|
|
|
|
@item drop_odd, 1
|
|
Only output even frames, odd frames are dropped, generating a frame with
|
|
unchanged height at half framerate.
|
|
|
|
@item drop_even, 2
|
|
Only output odd frames, even frames are dropped, generating a frame with
|
|
unchanged height at half framerate.
|
|
|
|
@item pad, 3
|
|
Expand each frame to full height, but pad alternate lines with black,
|
|
generating a frame with double height at the same input framerate.
|
|
|
|
@item interleave_top, 4
|
|
Interleave the upper field from odd frames with the lower field from
|
|
even frames, generating a frame with unchanged height at half framerate.
|
|
|
|
@item interleave_bottom, 5
|
|
Interleave the lower field from odd frames with the upper field from
|
|
even frames, generating a frame with unchanged height at half framerate.
|
|
|
|
@item interlacex2, 6
|
|
Double frame rate with unchanged height. Frames are inserted each
|
|
containing the second temporal field from the previous input frame and
|
|
the first temporal field from the next input frame. This mode relies on
|
|
the top_field_first flag. Useful for interlaced video displays with no
|
|
field synchronisation.
|
|
@end table
|
|
|
|
Numeric values are deprecated but are accepted for backward
|
|
compatibility reasons.
|
|
|
|
Default mode is @code{merge}.
|
|
|
|
@section transpose
|
|
|
|
Transpose rows with columns in the input video and optionally flip it.
|
|
|
|
This filter accepts the following named parameters:
|
|
|
|
@table @option
|
|
@item dir
|
|
Specify the transposition direction. Can assume the following values:
|
|
|
|
@table @samp
|
|
@item 0, 4
|
|
Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
|
|
@example
|
|
L.R L.l
|
|
. . -> . .
|
|
l.r R.r
|
|
@end example
|
|
|
|
@item 1, 5
|
|
Rotate by 90 degrees clockwise, that is:
|
|
@example
|
|
L.R l.L
|
|
. . -> . .
|
|
l.r r.R
|
|
@end example
|
|
|
|
@item 2, 6
|
|
Rotate by 90 degrees counterclockwise, that is:
|
|
@example
|
|
L.R R.r
|
|
. . -> . .
|
|
l.r L.l
|
|
@end example
|
|
|
|
@item 3, 7
|
|
Rotate by 90 degrees clockwise and vertically flip, that is:
|
|
@example
|
|
L.R r.R
|
|
. . -> . .
|
|
l.r l.L
|
|
@end example
|
|
@end table
|
|
|
|
For values between 4-7, the transposition is only done if the input
|
|
video geometry is portrait and not landscape. These values are
|
|
deprecated, the @code{passthrough} option should be used instead.
|
|
|
|
@item passthrough
|
|
Do not apply the transposition if the input geometry matches the one
|
|
specified by the specified value. It accepts the following values:
|
|
@table @samp
|
|
@item none
|
|
Always apply transposition.
|
|
@item portrait
|
|
Preserve portrait geometry (when @var{height} >= @var{width}).
|
|
@item landscape
|
|
Preserve landscape geometry (when @var{width} >= @var{height}).
|
|
@end table
|
|
|
|
Default value is @code{none}.
|
|
@end table
|
|
|
|
@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 '5:5:1.0:5:5:0.0'.
|
|
|
|
@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 5.
|
|
|
|
@item chroma_msize_y
|
|
Set the chroma matrix vertical size. It can be an integer between 3
|
|
and 13, default value is 5.
|
|
|
|
@item chroma_amount
|
|
Set the chroma effect strength. It can be a float number between -2.0
|
|
and 5.0, default value is 0.0.
|
|
|
|
@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{auto}.
|
|
|
|
@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.
|
|
|
|
@var{auto} specifies if deinterlacer should trust the interlaced flag
|
|
and only deinterlace frames marked as interlaced
|
|
|
|
@table @option
|
|
@item 0
|
|
deinterlace all frames
|
|
@item 1
|
|
only deinterlace frames marked as interlaced
|
|
@end table
|
|
|
|
Default value is 0.
|
|
|
|
@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 a list of options in the form of @var{key}=@var{value} pairs
|
|
separated by ":". A description of the accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item video_size
|
|
Specify the size (width and height) of the buffered video frames.
|
|
|
|
@item pix_fmt
|
|
A string representing the pixel format of the buffered video frames.
|
|
It may be a number corresponding to a pixel format, or a pixel format
|
|
name.
|
|
|
|
@item time_base
|
|
Specify the timebase assumed by the timestamps of the buffered frames.
|
|
|
|
@item time_base
|
|
Specify the frame rate expected for the video stream.
|
|
|
|
@item pixel_aspect
|
|
Specify the sample aspect ratio assumed by the video frames.
|
|
|
|
@item sws_param
|
|
Specify the optional parameters to be used for the scale filter which
|
|
is automatically inserted when an input change is detected in the
|
|
input size or format.
|
|
@end table
|
|
|
|
For example:
|
|
@example
|
|
buffer=size=320x240:pix_fmt=yuv410p:time_base=1/24:pixel_aspect=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 AVPixelFormat definition in @file{libavutil/pixfmt.h}),
|
|
this example corresponds to:
|
|
@example
|
|
buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
|
|
@end example
|
|
|
|
Alternatively, the options can be specified as a flat string, but this
|
|
syntax is deprecated:
|
|
|
|
@var{width}:@var{height}:@var{pix_fmt}:@var{time_base.num}:@var{time_base.den}:@var{pixel_aspect.num}:@var{pixel_aspect.den}[:@var{sws_param}]
|
|
|
|
@section cellauto
|
|
|
|
Create a pattern generated by an elementary cellular automaton.
|
|
|
|
The initial state of the cellular automaton can be defined through the
|
|
@option{filename}, and @option{pattern} options. If such options are
|
|
not specified an initial state is created randomly.
|
|
|
|
At each new frame a new row in the video is filled with the result of
|
|
the cellular automaton next generation. The behavior when the whole
|
|
frame is filled is defined by the @option{scroll} option.
|
|
|
|
This source accepts a list of options in the form of
|
|
@var{key}=@var{value} pairs separated by ":". A description of the
|
|
accepted options follows.
|
|
|
|
@table @option
|
|
@item filename, f
|
|
Read the initial cellular automaton state, i.e. the starting row, from
|
|
the specified file.
|
|
In the file, each non-whitespace character is considered an alive
|
|
cell, a newline will terminate the row, and further characters in the
|
|
file will be ignored.
|
|
|
|
@item pattern, p
|
|
Read the initial cellular automaton state, i.e. the starting row, from
|
|
the specified string.
|
|
|
|
Each non-whitespace character in the string is considered an alive
|
|
cell, a newline will terminate the row, and further characters in the
|
|
string will be ignored.
|
|
|
|
@item rate, r
|
|
Set the video rate, that is the number of frames generated per second.
|
|
Default is 25.
|
|
|
|
@item random_fill_ratio, ratio
|
|
Set the random fill ratio for the initial cellular automaton row. It
|
|
is a floating point number value ranging from 0 to 1, defaults to
|
|
1/PHI.
|
|
|
|
This option is ignored when a file or a pattern is specified.
|
|
|
|
@item random_seed, seed
|
|
Set the seed for filling randomly the initial row, must be an integer
|
|
included between 0 and UINT32_MAX. If not specified, or if explicitly
|
|
set to -1, the filter will try to use a good random seed on a best
|
|
effort basis.
|
|
|
|
@item rule
|
|
Set the cellular automaton rule, it is a number ranging from 0 to 255.
|
|
Default value is 110.
|
|
|
|
@item size, s
|
|
Set the size of the output video.
|
|
|
|
If @option{filename} or @option{pattern} is specified, the size is set
|
|
by default to the width of the specified initial state row, and the
|
|
height is set to @var{width} * PHI.
|
|
|
|
If @option{size} is set, it must contain the width of the specified
|
|
pattern string, and the specified pattern will be centered in the
|
|
larger row.
|
|
|
|
If a filename or a pattern string is not specified, the size value
|
|
defaults to "320x518" (used for a randomly generated initial state).
|
|
|
|
@item scroll
|
|
If set to 1, scroll the output upward when all the rows in the output
|
|
have been already filled. If set to 0, the new generated row will be
|
|
written over the top row just after the bottom row is filled.
|
|
Defaults to 1.
|
|
|
|
@item start_full, full
|
|
If set to 1, completely fill the output with generated rows before
|
|
outputting the first frame.
|
|
This is the default behavior, for disabling set the value to 0.
|
|
|
|
@item stitch
|
|
If set to 1, stitch the left and right row edges together.
|
|
This is the default behavior, for disabling set the value to 0.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Read the initial state from @file{pattern}, and specify an output of
|
|
size 200x400.
|
|
@example
|
|
cellauto=f=pattern:s=200x400
|
|
@end example
|
|
|
|
@item
|
|
Generate a random initial row with a width of 200 cells, with a fill
|
|
ratio of 2/3:
|
|
@example
|
|
cellauto=ratio=2/3:s=200x200
|
|
@end example
|
|
|
|
@item
|
|
Create a pattern generated by rule 18 starting by a single alive cell
|
|
centered on an initial row with width 100:
|
|
@example
|
|
cellauto=p=@@:s=100x400:full=0:rule=18
|
|
@end example
|
|
|
|
@item
|
|
Specify a more elaborated initial pattern:
|
|
@example
|
|
cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
|
|
@end example
|
|
|
|
@end itemize
|
|
|
|
@section mandelbrot
|
|
|
|
Generate a Mandelbrot set fractal, and progressively zoom towards the
|
|
point specified with @var{start_x} and @var{start_y}.
|
|
|
|
This source accepts a list of options in the form of
|
|
@var{key}=@var{value} pairs separated by ":". A description of the
|
|
accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item end_pts
|
|
Set the terminal pts value. Default value is 400.
|
|
|
|
@item end_scale
|
|
Set the terminal scale value.
|
|
Must be a floating point value. Default value is 0.3.
|
|
|
|
@item inner
|
|
Set the inner coloring mode, that is the algorithm used to draw the
|
|
Mandelbrot fractal internal region.
|
|
|
|
It shall assume one of the following values:
|
|
@table @option
|
|
@item black
|
|
Set black mode.
|
|
@item convergence
|
|
Show time until convergence.
|
|
@item mincol
|
|
Set color based on point closest to the origin of the iterations.
|
|
@item period
|
|
Set period mode.
|
|
@end table
|
|
|
|
Default value is @var{mincol}.
|
|
|
|
@item bailout
|
|
Set the bailout value. Default value is 10.0.
|
|
|
|
@item maxiter
|
|
Set the maximum of iterations performed by the rendering
|
|
algorithm. Default value is 7189.
|
|
|
|
@item outer
|
|
Set outer coloring mode.
|
|
It shall assume one of following values:
|
|
@table @option
|
|
@item iteration_count
|
|
Set iteration cound mode.
|
|
@item normalized_iteration_count
|
|
set normalized iteration count mode.
|
|
@end table
|
|
Default value is @var{normalized_iteration_count}.
|
|
|
|
@item rate, r
|
|
Set frame rate, expressed as number of frames per second. Default
|
|
value is "25".
|
|
|
|
@item size, s
|
|
Set frame size. Default value is "640x480".
|
|
|
|
@item start_scale
|
|
Set the initial scale value. Default value is 3.0.
|
|
|
|
@item start_x
|
|
Set the initial x position. Must be a floating point value between
|
|
-100 and 100. Default value is -0.743643887037158704752191506114774.
|
|
|
|
@item start_y
|
|
Set the initial y position. Must be a floating point value between
|
|
-100 and 100. Default value is -0.131825904205311970493132056385139.
|
|
@end table
|
|
|
|
@section mptestsrc
|
|
|
|
Generate various test patterns, as generated by the MPlayer test filter.
|
|
|
|
The size of the generated video is fixed, and is 256x256.
|
|
This source is useful in particular for testing encoding features.
|
|
|
|
This source accepts an optional sequence of @var{key}=@var{value} pairs,
|
|
separated by ":". The description of the accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item rate, r
|
|
Specify the frame rate of the sourced video, as the number of frames
|
|
generated per second. It has to be a string in the format
|
|
@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
|
|
number or a valid video frame rate abbreviation. The default value is
|
|
"25".
|
|
|
|
@item duration, d
|
|
Set the video duration of the sourced video. The accepted syntax is:
|
|
@example
|
|
[-]HH:MM:SS[.m...]
|
|
[-]S+[.m...]
|
|
@end example
|
|
See also the function @code{av_parse_time()}.
|
|
|
|
If not specified, or the expressed duration is negative, the video is
|
|
supposed to be generated forever.
|
|
|
|
@item test, t
|
|
|
|
Set the number or the name of the test to perform. Supported tests are:
|
|
@table @option
|
|
@item dc_luma
|
|
@item dc_chroma
|
|
@item freq_luma
|
|
@item freq_chroma
|
|
@item amp_luma
|
|
@item amp_chroma
|
|
@item cbp
|
|
@item mv
|
|
@item ring1
|
|
@item ring2
|
|
@item all
|
|
@end table
|
|
|
|
Default value is "all", which will cycle through the list of all tests.
|
|
@end table
|
|
|
|
For example the following:
|
|
@example
|
|
testsrc=t=dc_luma
|
|
@end example
|
|
|
|
will generate a "dc_luma" test pattern.
|
|
|
|
@section frei0r_src
|
|
|
|
Provide a frei0r source.
|
|
|
|
To enable compilation of this filter you need to install the frei0r
|
|
header and configure FFmpeg with @code{--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 @ref{frei0r} in the description of the video filters.
|
|
|
|
For example, to generate a frei0r partik0l source with size 200x200
|
|
and frame rate 10 which is overlayed on the overlay filter main input:
|
|
@example
|
|
frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
|
|
@end example
|
|
|
|
@section life
|
|
|
|
Generate a life pattern.
|
|
|
|
This source is based on a generalization of John Conway's life game.
|
|
|
|
The sourced input represents a life grid, each pixel represents a cell
|
|
which can be in one of two possible states, alive or dead. Every cell
|
|
interacts with its eight neighbours, which are the cells that are
|
|
horizontally, vertically, or diagonally adjacent.
|
|
|
|
At each interaction the grid evolves according to the adopted rule,
|
|
which specifies the number of neighbor alive cells which will make a
|
|
cell stay alive or born. The @option{rule} option allows to specify
|
|
the rule to adopt.
|
|
|
|
This source accepts a list of options in the form of
|
|
@var{key}=@var{value} pairs separated by ":". A description of the
|
|
accepted options follows.
|
|
|
|
@table @option
|
|
@item filename, f
|
|
Set the file from which to read the initial grid state. In the file,
|
|
each non-whitespace character is considered an alive cell, and newline
|
|
is used to delimit the end of each row.
|
|
|
|
If this option is not specified, the initial grid is generated
|
|
randomly.
|
|
|
|
@item rate, r
|
|
Set the video rate, that is the number of frames generated per second.
|
|
Default is 25.
|
|
|
|
@item random_fill_ratio, ratio
|
|
Set the random fill ratio for the initial random grid. It is a
|
|
floating point number value ranging from 0 to 1, defaults to 1/PHI.
|
|
It is ignored when a file is specified.
|
|
|
|
@item random_seed, seed
|
|
Set the seed for filling the initial random grid, must be an integer
|
|
included between 0 and UINT32_MAX. If not specified, or if explicitly
|
|
set to -1, the filter will try to use a good random seed on a best
|
|
effort basis.
|
|
|
|
@item rule
|
|
Set the life rule.
|
|
|
|
A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
|
|
where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
|
|
@var{NS} specifies the number of alive neighbor cells which make a
|
|
live cell stay alive, and @var{NB} the number of alive neighbor cells
|
|
which make a dead cell to become alive (i.e. to "born").
|
|
"s" and "b" can be used in place of "S" and "B", respectively.
|
|
|
|
Alternatively a rule can be specified by an 18-bits integer. The 9
|
|
high order bits are used to encode the next cell state if it is alive
|
|
for each number of neighbor alive cells, the low order bits specify
|
|
the rule for "borning" new cells. Higher order bits encode for an
|
|
higher number of neighbor cells.
|
|
For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
|
|
rule of 12 and a born rule of 9, which corresponds to "S23/B03".
|
|
|
|
Default value is "S23/B3", which is the original Conway's game of life
|
|
rule, and will keep a cell alive if it has 2 or 3 neighbor alive
|
|
cells, and will born a new cell if there are three alive cells around
|
|
a dead cell.
|
|
|
|
@item size, s
|
|
Set the size of the output video.
|
|
|
|
If @option{filename} is specified, the size is set by default to the
|
|
same size of the input file. If @option{size} is set, it must contain
|
|
the size specified in the input file, and the initial grid defined in
|
|
that file is centered in the larger resulting area.
|
|
|
|
If a filename is not specified, the size value defaults to "320x240"
|
|
(used for a randomly generated initial grid).
|
|
|
|
@item stitch
|
|
If set to 1, stitch the left and right grid edges together, and the
|
|
top and bottom edges also. Defaults to 1.
|
|
|
|
@item mold
|
|
Set cell mold speed. If set, a dead cell will go from @option{death_color} to
|
|
@option{mold_color} with a step of @option{mold}. @option{mold} can have a
|
|
value from 0 to 255.
|
|
|
|
@item life_color
|
|
Set the color of living (or new born) cells.
|
|
|
|
@item death_color
|
|
Set the color of dead cells. If @option{mold} is set, this is the first color
|
|
used to represent a dead cell.
|
|
|
|
@item mold_color
|
|
Set mold color, for definitely dead and moldy cells.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Read a grid from @file{pattern}, and center it on a grid of size
|
|
300x300 pixels:
|
|
@example
|
|
life=f=pattern:s=300x300
|
|
@end example
|
|
|
|
@item
|
|
Generate a random grid of size 200x200, with a fill ratio of 2/3:
|
|
@example
|
|
life=ratio=2/3:s=200x200
|
|
@end example
|
|
|
|
@item
|
|
Specify a custom rule for evolving a randomly generated grid:
|
|
@example
|
|
life=rule=S14/B34
|
|
@end example
|
|
|
|
@item
|
|
Full example with slow death effect (mold) using @command{ffplay}:
|
|
@example
|
|
ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
|
|
@end example
|
|
@end itemize
|
|
|
|
@section color, nullsrc, rgbtestsrc, smptebars, testsrc
|
|
|
|
The @code{color} source provides an uniformly colored input.
|
|
|
|
The @code{nullsrc} source returns unprocessed video frames. It is
|
|
mainly useful to be employed in analysis / debugging tools, or as the
|
|
source for filters which ignore the input data.
|
|
|
|
The @code{rgbtestsrc} source generates an RGB test pattern useful for
|
|
detecting RGB vs BGR issues. You should see a red, green and blue
|
|
stripe from top to bottom.
|
|
|
|
The @code{smptebars} source generates a color bars pattern, based on
|
|
the SMPTE Engineering Guideline EG 1-1990.
|
|
|
|
The @code{testsrc} source generates a test video pattern, showing a
|
|
color pattern, a scrolling gradient and a timestamp. This is mainly
|
|
intended for testing purposes.
|
|
|
|
These sources accept an optional sequence of @var{key}=@var{value} pairs,
|
|
separated by ":". The description of the accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item color, c
|
|
Specify the color of the source, only used in the @code{color}
|
|
source. It can be the name of a color (case insensitive match) or a
|
|
0xRRGGBB[AA] sequence, possibly followed by an alpha specifier. The
|
|
default value is "black".
|
|
|
|
@item size, s
|
|
Specify the size of the sourced video, it may be a string of the form
|
|
@var{width}x@var{height}, or the name of a size abbreviation. The
|
|
default value is "320x240".
|
|
|
|
@item rate, r
|
|
Specify the frame rate of the sourced video, as the number of frames
|
|
generated per second. It has to be a string in the format
|
|
@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
|
|
number or a valid video frame rate abbreviation. The default value is
|
|
"25".
|
|
|
|
@item sar
|
|
Set the sample aspect ratio of the sourced video.
|
|
|
|
@item duration, d
|
|
Set the video duration of the sourced video. The accepted syntax is:
|
|
@example
|
|
[-]HH[:MM[:SS[.m...]]]
|
|
[-]S+[.m...]
|
|
@end example
|
|
See also the function @code{av_parse_time()}.
|
|
|
|
If not specified, or the expressed duration is negative, the video is
|
|
supposed to be generated forever.
|
|
|
|
@item decimals, n
|
|
Set the number of decimals to show in the timestamp, only used in the
|
|
@code{testsrc} source.
|
|
|
|
The displayed timestamp value will correspond to the original
|
|
timestamp value multiplied by the power of 10 of the specified
|
|
value. Default value is 0.
|
|
@end table
|
|
|
|
For example the following:
|
|
@example
|
|
testsrc=duration=5.3:size=qcif:rate=10
|
|
@end example
|
|
|
|
will generate a video with a duration of 5.3 seconds, with size
|
|
176x144 and a frame rate of 10 frames per second.
|
|
|
|
The following graph description will generate a red source
|
|
with an opacity of 0.2, with size "qcif" and a frame rate of 10
|
|
frames per second.
|
|
@example
|
|
color=c=red@@0.2:s=qcif:r=10
|
|
@end example
|
|
|
|
If the input content is to be ignored, @code{nullsrc} can be used. The
|
|
following command generates noise in the luminance plane by employing
|
|
the @code{geq} filter:
|
|
@example
|
|
nullsrc=s=256x256, geq=random(1)*255:128:128
|
|
@end example
|
|
|
|
@c man end VIDEO SOURCES
|
|
|
|
@chapter Video Sinks
|
|
@c man begin VIDEO SINKS
|
|
|
|
Below is a description of the currently available video sinks.
|
|
|
|
@section buffersink
|
|
|
|
Buffer video frames, and make them available to the end of the filter
|
|
graph.
|
|
|
|
This sink is mainly intended for a programmatic use, in particular
|
|
through the interface defined in @file{libavfilter/buffersink.h}.
|
|
|
|
It does not require a string parameter in input, but you need to
|
|
specify a pointer to a list of supported pixel formats terminated by
|
|
-1 in the opaque parameter provided to @code{avfilter_init_filter}
|
|
when initializing this sink.
|
|
|
|
@section nullsink
|
|
|
|
Null video sink, do absolutely nothing with the input video. It is
|
|
mainly useful as a template and to be employed in analysis / debugging
|
|
tools.
|
|
|
|
@c man end VIDEO SINKS
|
|
|
|
@chapter Multimedia Filters
|
|
@c man begin MULTIMEDIA FILTERS
|
|
|
|
Below is a description of the currently available multimedia filters.
|
|
|
|
@section asendcmd, sendcmd
|
|
|
|
Send commands to filters in the filtergraph.
|
|
|
|
These filters read commands to be sent to other filters in the
|
|
filtergraph.
|
|
|
|
@code{asendcmd} must be inserted between two audio filters,
|
|
@code{sendcmd} must be inserted between two video filters, but apart
|
|
from that they act the same way.
|
|
|
|
The specification of commands can be provided in the filter arguments
|
|
with the @var{commands} option, or in a file specified by the
|
|
@var{filename} option.
|
|
|
|
These filters accept the following options:
|
|
@table @option
|
|
@item commands, c
|
|
Set the commands to be read and sent to the other filters.
|
|
@item filename, f
|
|
Set the filename of the commands to be read and sent to the other
|
|
filters.
|
|
@end table
|
|
|
|
@subsection Commands syntax
|
|
|
|
A commands description consists of a sequence of interval
|
|
specifications, comprising a list of commands to be executed when a
|
|
particular event related to that interval occurs. The occurring event
|
|
is typically the current frame time entering or leaving a given time
|
|
interval.
|
|
|
|
An interval is specified by the following syntax:
|
|
@example
|
|
@var{START}[-@var{END}] @var{COMMANDS};
|
|
@end example
|
|
|
|
The time interval is specified by the @var{START} and @var{END} times.
|
|
@var{END} is optional and defaults to the maximum time.
|
|
|
|
The current frame time is considered within the specified interval if
|
|
it is included in the interval [@var{START}, @var{END}), that is when
|
|
the time is greater or equal to @var{START} and is lesser than
|
|
@var{END}.
|
|
|
|
@var{COMMANDS} consists of a sequence of one or more command
|
|
specifications, separated by ",", relating to that interval. The
|
|
syntax of a command specification is given by:
|
|
@example
|
|
[@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
|
|
@end example
|
|
|
|
@var{FLAGS} is optional and specifies the type of events relating to
|
|
the time interval which enable sending the specified command, and must
|
|
be a non-null sequence of identifier flags separated by "+" or "|" and
|
|
enclosed between "[" and "]".
|
|
|
|
The following flags are recognized:
|
|
@table @option
|
|
@item enter
|
|
The command is sent when the current frame timestamp enters the
|
|
specified interval. In other words, the command is sent when the
|
|
previous frame timestamp was not in the given interval, and the
|
|
current is.
|
|
|
|
@item leave
|
|
The command is sent when the current frame timestamp leaves the
|
|
specified interval. In other words, the command is sent when the
|
|
previous frame timestamp was in the given interval, and the
|
|
current is not.
|
|
@end table
|
|
|
|
If @var{FLAGS} is not specified, a default value of @code{[enter]} is
|
|
assumed.
|
|
|
|
@var{TARGET} specifies the target of the command, usually the name of
|
|
the filter class or a specific filter instance name.
|
|
|
|
@var{COMMAND} specifies the name of the command for the target filter.
|
|
|
|
@var{ARG} is optional and specifies the optional list of argument for
|
|
the given @var{COMMAND}.
|
|
|
|
Between one interval specification and another, whitespaces, or
|
|
sequences of characters starting with @code{#} until the end of line,
|
|
are ignored and can be used to annotate comments.
|
|
|
|
A simplified BNF description of the commands specification syntax
|
|
follows:
|
|
@example
|
|
@var{COMMAND_FLAG} ::= "enter" | "leave"
|
|
@var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
|
|
@var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
|
|
@var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
|
|
@var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
|
|
@var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
|
|
@end example
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Specify audio tempo change at second 4:
|
|
@example
|
|
asendcmd=c='4.0 atempo tempo 1.5',atempo
|
|
@end example
|
|
|
|
@item
|
|
Specify a list of drawtext and hue commands in a file.
|
|
@example
|
|
# show text in the interval 5-10
|
|
5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
|
|
[leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
|
|
|
|
# desaturate the image in the interval 15-20
|
|
15.0-20.0 [enter] hue reinit s=0,
|
|
[enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
|
|
[leave] hue reinit s=1,
|
|
[leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
|
|
|
|
# apply an exponential saturation fade-out effect, starting from time 25
|
|
25 [enter] hue s=exp(t-25)
|
|
@end example
|
|
|
|
A filtergraph allowing to read and process the above command list
|
|
stored in a file @file{test.cmd}, can be specified with:
|
|
@example
|
|
sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
|
|
@end example
|
|
@end itemize
|
|
|
|
@section asetpts, setpts
|
|
|
|
Change the PTS (presentation timestamp) of the input frames.
|
|
|
|
@code{asetpts} works on audio frames, @code{setpts} on video frames.
|
|
|
|
Accept in input an expression evaluated through the eval API, which
|
|
can contain the following constants:
|
|
|
|
@table @option
|
|
@item FRAME_RATE
|
|
frame rate, only defined for constant frame-rate video
|
|
|
|
@item PTS
|
|
the presentation timestamp in input
|
|
|
|
@item N
|
|
the count of the input frame, starting from 0.
|
|
|
|
@item NB_CONSUMED_SAMPLES
|
|
the number of consumed samples, not including the current frame (only
|
|
audio)
|
|
|
|
@item NB_SAMPLES
|
|
the number of samples in the current frame (only audio)
|
|
|
|
@item SAMPLE_RATE
|
|
audio sample rate
|
|
|
|
@item STARTPTS
|
|
the PTS of the first frame
|
|
|
|
@item STARTT
|
|
the time in seconds of the first frame
|
|
|
|
@item INTERLACED
|
|
tell if the current frame is interlaced
|
|
|
|
@item T
|
|
the time in seconds of the current frame
|
|
|
|
@item TB
|
|
the time base
|
|
|
|
@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_INT
|
|
previous input time in seconds
|
|
|
|
@item PREV_OUTPTS
|
|
previous output PTS
|
|
|
|
@item PREV_OUTT
|
|
previous output time in seconds
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Start counting PTS from zero
|
|
@example
|
|
setpts=PTS-STARTPTS
|
|
@end example
|
|
|
|
@item
|
|
Apply fast motion effect:
|
|
@example
|
|
setpts=0.5*PTS
|
|
@end example
|
|
|
|
@item
|
|
Apply slow motion effect:
|
|
@example
|
|
setpts=2.0*PTS
|
|
@end example
|
|
|
|
@item
|
|
Set fixed rate of 25 frames per second:
|
|
@example
|
|
setpts=N/(25*TB)
|
|
@end example
|
|
|
|
@item
|
|
Set fixed rate 25 fps with some jitter:
|
|
@example
|
|
setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
|
|
@end example
|
|
|
|
@item
|
|
Apply an offset of 10 seconds to the input PTS:
|
|
@example
|
|
setpts=PTS+10/TB
|
|
@end example
|
|
@end itemize
|
|
|
|
@section ebur128
|
|
|
|
EBU R128 scanner filter. This filter takes an audio stream as input and outputs
|
|
it unchanged. By default, it logs a message at a frequency of 10Hz with the
|
|
Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
|
|
Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
|
|
|
|
The filter also has a video output (see the @var{video} option) with a real
|
|
time graph to observe the loudness evolution. The graphic contains the logged
|
|
message mentioned above, so it is not printed anymore when this option is set,
|
|
unless the verbose logging is set. The main graphing area contains the
|
|
short-term loudness (3 seconds of analysis), and the gauge on the right is for
|
|
the momentary loudness (400 milliseconds).
|
|
|
|
More information about the Loudness Recommendation EBU R128 on
|
|
@url{http://tech.ebu.ch/loudness}.
|
|
|
|
The filter accepts the following named parameters:
|
|
|
|
@table @option
|
|
|
|
@item video
|
|
Activate the video output. The audio stream is passed unchanged whether this
|
|
option is set or no. The video stream will be the first output stream if
|
|
activated. Default is @code{0}.
|
|
|
|
@item size
|
|
Set the video size. This option is for video only. Default and minimum
|
|
resolution is @code{640x480}.
|
|
|
|
@item meter
|
|
Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
|
|
@code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
|
|
other integer value between this range is allowed.
|
|
|
|
@end table
|
|
|
|
Example of real-time graph using @command{ffplay}, with a EBU scale meter +18:
|
|
@example
|
|
ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
|
|
@end example
|
|
|
|
Run an analysis with @command{ffmpeg}:
|
|
@example
|
|
ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
|
|
@end example
|
|
|
|
@section settb, asettb
|
|
|
|
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 "AVTB" (the
|
|
default timebase), "intb" (the input timebase) and "sr" (the sample rate,
|
|
audio only).
|
|
|
|
The default value for the input is "intb".
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Set the timebase to 1/25:
|
|
@example
|
|
settb=1/25
|
|
@end example
|
|
|
|
@item
|
|
Set the timebase to 1/10:
|
|
@example
|
|
settb=0.1
|
|
@end example
|
|
|
|
@item
|
|
Set the timebase to 1001/1000:
|
|
@example
|
|
settb=1+0.001
|
|
@end example
|
|
|
|
@item
|
|
Set the timebase to 2*intb:
|
|
@example
|
|
settb=2*intb
|
|
@end example
|
|
|
|
@item
|
|
Set the default timebase value:
|
|
@example
|
|
settb=AVTB
|
|
@end example
|
|
@end itemize
|
|
|
|
@section concat
|
|
|
|
Concatenate audio and video streams, joining them together one after the
|
|
other.
|
|
|
|
The filter works on segments of synchronized video and audio streams. All
|
|
segments must have the same number of streams of each type, and that will
|
|
also be the number of streams at output.
|
|
|
|
The filter accepts the following named parameters:
|
|
@table @option
|
|
|
|
@item n
|
|
Set the number of segments. Default is 2.
|
|
|
|
@item v
|
|
Set the number of output video streams, that is also the number of video
|
|
streams in each segment. Default is 1.
|
|
|
|
@item a
|
|
Set the number of output audio streams, that is also the number of video
|
|
streams in each segment. Default is 0.
|
|
|
|
@item unsafe
|
|
Activate unsafe mode: do not fail if segments have a different format.
|
|
|
|
@end table
|
|
|
|
The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
|
|
@var{a} audio outputs.
|
|
|
|
There are @var{n}×(@var{v}+@var{a}) inputs: first the inputs for the first
|
|
segment, in the same order as the outputs, then the inputs for the second
|
|
segment, etc.
|
|
|
|
Related streams do not always have exactly the same duration, for various
|
|
reasons including codec frame size or sloppy authoring. For that reason,
|
|
related synchronized streams (e.g. a video and its audio track) should be
|
|
concatenated at once. The concat filter will use the duration of the longest
|
|
stream in each segment (except the last one), and if necessary pad shorter
|
|
audio streams with silence.
|
|
|
|
For this filter to work correctly, all segments must start at timestamp 0.
|
|
|
|
All corresponding streams must have the same parameters in all segments; the
|
|
filtering system will automatically select a common pixel format for video
|
|
streams, and a common sample format, sample rate and channel layout for
|
|
audio streams, but other settings, such as resolution, must be converted
|
|
explicitly by the user.
|
|
|
|
Different frame rates are acceptable but will result in variable frame rate
|
|
at output; be sure to configure the output file to handle it.
|
|
|
|
Examples:
|
|
@itemize
|
|
@item
|
|
Concatenate an opening, an episode and an ending, all in bilingual version
|
|
(video in stream 0, audio in streams 1 and 2):
|
|
@example
|
|
ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
|
|
'[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
|
|
concat=n=3:v=1:a=2 [v] [a1] [a2]' \
|
|
-map '[v]' -map '[a1]' -map '[a2]' output.mkv
|
|
@end example
|
|
|
|
@item
|
|
Concatenate two parts, handling audio and video separately, using the
|
|
(a)movie sources, and adjusting the resolution:
|
|
@example
|
|
movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
|
|
movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
|
|
[v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
|
|
@end example
|
|
Note that a desync will happen at the stitch if the audio and video streams
|
|
do not have exactly the same duration in the first file.
|
|
|
|
@end itemize
|
|
|
|
@section showspectrum
|
|
|
|
Convert input audio to a video output, representing the audio frequency
|
|
spectrum.
|
|
|
|
The filter accepts the following named parameters:
|
|
@table @option
|
|
@item size, s
|
|
Specify the video size for the output. Default value is @code{640x480}.
|
|
@item slide
|
|
Specify if the spectrum should slide along the window. Default value is
|
|
@code{0}.
|
|
@end table
|
|
|
|
The usage is very similar to the showwaves filter; see the examples in that
|
|
section.
|
|
|
|
@section showwaves
|
|
|
|
Convert input audio to a video output, representing the samples waves.
|
|
|
|
The filter accepts the following named parameters:
|
|
@table @option
|
|
|
|
@item n
|
|
Set the number of samples which are printed on the same column. A
|
|
larger value will decrease the frame rate. Must be a positive
|
|
integer. This option can be set only if the value for @var{rate}
|
|
is not explicitly specified.
|
|
|
|
@item rate, r
|
|
Set the (approximate) output frame rate. This is done by setting the
|
|
option @var{n}. Default value is "25".
|
|
|
|
@item size, s
|
|
Specify the video size for the output. Default value is "600x240".
|
|
@end table
|
|
|
|
Some examples follow.
|
|
@itemize
|
|
@item
|
|
Output the input file audio and the corresponding video representation
|
|
at the same time:
|
|
@example
|
|
amovie=a.mp3,asplit[out0],showwaves[out1]
|
|
@end example
|
|
|
|
@item
|
|
Create a synthetic signal and show it with showwaves, forcing a
|
|
framerate of 30 frames per second:
|
|
@example
|
|
aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
|
|
@end example
|
|
@end itemize
|
|
|
|
@c man end MULTIMEDIA FILTERS
|
|
|
|
@chapter Multimedia Sources
|
|
@c man begin MULTIMEDIA SOURCES
|
|
|
|
Below is a description of the currently available multimedia sources.
|
|
|
|
@section amovie
|
|
|
|
This is the same as @ref{src_movie} source, except it selects an audio
|
|
stream by default.
|
|
|
|
@anchor{src_movie}
|
|
@section movie
|
|
|
|
Read audio and/or video stream(s) 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 streams, s
|
|
Specifies the streams to read. Several streams can be specified, separated
|
|
by "+". The source will then have as many outputs, in the same order. The
|
|
syntax is explained in the @ref{Stream specifiers} chapter. Two special
|
|
names, "dv" and "da" specify respectively the default (best suited) video
|
|
and audio stream. Default is "dv", or "da" if the filter is called as
|
|
"amovie".
|
|
|
|
@item stream_index, si
|
|
Specifies the index of the video stream to read. If the value is -1,
|
|
the best suited video stream will be automatically selected. Default
|
|
value is "-1". Deprecated. If the filter is called "amovie", it will select
|
|
audio instead of video.
|
|
|
|
@item loop
|
|
Specifies how many times to read the stream in sequence.
|
|
If the value is less than 1, the stream will be read again and again.
|
|
Default value is "1".
|
|
|
|
Note that when the movie is looped the source timestamps are not
|
|
changed, so it will generate non monotonically increasing timestamps.
|
|
@end table
|
|
|
|
This filter allows to overlay a second video on top of main input of
|
|
a filtergraph as shown in this graph:
|
|
@example
|
|
input -----------> deltapts0 --> overlay --> output
|
|
^
|
|
|
|
|
movie --> scale--> deltapts1 -------+
|
|
@end example
|
|
|
|
Some examples follow.
|
|
|
|
@itemize
|
|
@item
|
|
Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
|
|
on top of the input labelled as "in":
|
|
@example
|
|
movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
|
|
[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
|
|
@end example
|
|
|
|
@item
|
|
Read from a video4linux2 device, and overlay it on top of the input
|
|
labelled as "in":
|
|
@example
|
|
movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
|
|
[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
|
|
@end example
|
|
|
|
@item
|
|
Read the first video stream and the audio stream with id 0x81 from
|
|
dvd.vob; the video is connected to the pad named "video" and the audio is
|
|
connected to the pad named "audio":
|
|
@example
|
|
movie=dvd.vob:s=v:0+#0x81 [video] [audio]
|
|
@end example
|
|
@end itemize
|
|
|
|
@c man end MULTIMEDIA SOURCES
|