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1354 lines
38 KiB
1354 lines
38 KiB
@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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|
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Each filter in a filtergraph is an instance of a filter class |
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registered in the application, which defines the features and the |
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number of input and output pads of the filter. |
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A filter with no input pads is called a "source", a filter with no |
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output pads is called a "sink". |
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@section Filtergraph syntax |
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A filtergraph can be represented using a textual representation, which |
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is recognized by the @code{-vf} and @code{-af} options of the ff* |
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tools, and by the @code{av_parse_graph()} function defined in |
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@file{libavfilter/avfiltergraph}. |
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A filterchain consists of a sequence of connected filters, each one |
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connected to the previous one in the sequence. A filterchain is |
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represented by a list of ","-separated filter descriptions. |
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A filtergraph consists of a sequence of filterchains. A sequence of |
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filterchains is represented by a list of ";"-separated filterchain |
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descriptions. |
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A filter is represented by a string of the form: |
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[@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}] |
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@var{filter_name} is the name of the filter class of which the |
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described filter is an instance of, and has to be the name of one of |
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the filter classes registered in the program. |
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The name of the filter class is optionally followed by a string |
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"=@var{arguments}". |
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@var{arguments} is a string which contains the parameters used to |
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initialize the filter instance, and are described in the filter |
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descriptions below. |
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The list of arguments can be quoted using the character "'" as initial |
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and ending mark, and the character '\' for escaping the characters |
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within the quoted text; otherwise the argument string is considered |
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terminated when the next special character (belonging to the set |
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"[]=;,") is encountered. |
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The name and arguments of the filter are optionally preceded and |
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followed by a list of link labels. |
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A link label allows to name a link and associate it to a filter output |
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or input pad. The preceding labels @var{in_link_1} |
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... @var{in_link_N}, are associated to the filter input pads, |
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the following labels @var{out_link_1} ... @var{out_link_M}, are |
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associated to the output pads. |
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When two link labels with the same name are found in the |
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filtergraph, a link between the corresponding input and output pad is |
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created. |
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If an output pad is not labelled, it is linked by default to the first |
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unlabelled input pad of the next filter in the filterchain. |
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For example in the filterchain: |
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@example |
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nullsrc, split[L1], [L2]overlay, nullsink |
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@end example |
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the split filter instance has two output pads, and the overlay filter |
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instance two input pads. The first output pad of split is labelled |
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"L1", the first input pad of overlay is labelled "L2", and the second |
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output pad of split is linked to the second input pad of overlay, |
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which are both unlabelled. |
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In a complete filterchain all the unlabelled filter input and output |
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pads must be connected. A filtergraph is considered valid if all the |
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filter input and output pads of all the filterchains are connected. |
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|
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Follows a BNF description for the filtergraph syntax: |
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@example |
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@var{NAME} ::= sequence of alphanumeric characters and '_' |
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@var{LINKLABEL} ::= "[" @var{NAME} "]" |
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@var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}] |
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@var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted) |
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@var{FILTER} ::= [@var{LINKNAMES}] @var{NAME} ["=" @var{ARGUMENTS}] [@var{LINKNAMES}] |
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@var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}] |
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@var{FILTERGRAPH} ::= @var{FILTERCHAIN} [;@var{FILTERGRAPH}] |
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@end example |
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@c man end FILTERGRAPH DESCRIPTION |
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@chapter Audio Filters |
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@c man begin AUDIO FILTERS |
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When you configure your FFmpeg build, you can disable any of the |
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existing filters using --disable-filters. |
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The configure output will show the audio filters included in your |
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build. |
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Below is a description of the currently available audio filters. |
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@section anull |
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Pass the audio source unchanged to the output. |
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@c man end AUDIO FILTERS |
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@chapter Audio Sources |
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@c man begin AUDIO SOURCES |
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Below is a description of the currently available audio sources. |
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@section anullsrc |
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Null audio source, never return audio frames. It is mainly useful as a |
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template and to be employed in analysis / debugging tools. |
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It accepts as optional parameter a string of the form |
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@var{sample_rate}:@var{channel_layout}. |
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@var{sample_rate} specify the sample rate, and defaults to 44100. |
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@var{channel_layout} specify the channel layout, and can be either an |
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integer or a string representing a channel layout. The default value |
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of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO. |
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Check the channel_layout_map definition in |
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@file{libavcodec/audioconvert.c} for the mapping between strings and |
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channel layout values. |
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Follow some examples: |
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@example |
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# set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO. |
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anullsrc=48000:4 |
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# same as |
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anullsrc=48000:mono |
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@end example |
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@c man end AUDIO SOURCES |
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@chapter Audio Sinks |
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@c man begin AUDIO SINKS |
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Below is a description of the currently available audio sinks. |
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@section anullsink |
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Null audio sink, do absolutely nothing with the input audio. It is |
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mainly useful as a template and to be employed in analysis / debugging |
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tools. |
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@c man end AUDIO SINKS |
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@chapter Video Filters |
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@c man begin VIDEO FILTERS |
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When you configure your FFmpeg build, you can disable any of the |
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existing filters using --disable-filters. |
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The configure output will show the video filters included in your |
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build. |
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Below is a description of the currently available video filters. |
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@section blackframe |
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Detect frames that are (almost) completely black. Can be useful to |
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detect chapter transitions or commercials. Output lines consist of |
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the frame number of the detected frame, the percentage of blackness, |
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the position in the file if known or -1 and the timestamp in seconds. |
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In order to display the output lines, you need to set the loglevel at |
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least to the AV_LOG_INFO value. |
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The filter accepts the syntax: |
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@example |
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blackframe[=@var{amount}:[@var{threshold}]] |
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@end example |
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@var{amount} is the percentage of the pixels that have to be below the |
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threshold, and defaults to 98. |
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@var{threshold} is the threshold below which a pixel value is |
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considered black, and defaults to 32. |
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@section copy |
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Copy the input source unchanged to the output. Mainly useful for |
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testing purposes. |
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@section crop |
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Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}. |
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The parameters are expressions containing the following constants: |
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@table @option |
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@item E, PI, PHI |
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the corresponding mathematical approximated values for e |
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(euler number), pi (greek PI), PHI (golden ratio) |
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@item x, y |
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the computed values for @var{x} and @var{y}. They are evaluated for |
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each new frame. |
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@item in_w, in_h |
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the input width and heigth |
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@item iw, ih |
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same as @var{in_w} and @var{in_h} |
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@item out_w, out_h |
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the output (cropped) width and heigth |
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@item ow, oh |
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same as @var{out_w} and @var{out_h} |
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@item n |
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the number of input frame, starting from 0 |
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@item pos |
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the position in the file of the input frame, NAN if unknown |
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@item t |
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timestamp expressed in seconds, NAN if the input timestamp is unknown |
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@end table |
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The @var{out_w} and @var{out_h} parameters specify the expressions for |
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the width and height of the output (cropped) video. They are |
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evaluated just at the configuration of the filter. |
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The default value of @var{out_w} is "in_w", and the default value of |
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@var{out_h} is "in_h". |
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The expression for @var{out_w} may depend on the value of @var{out_h}, |
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and the expression for @var{out_h} may depend on @var{out_w}, but they |
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cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are |
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evaluated after @var{out_w} and @var{out_h}. |
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The @var{x} and @var{y} parameters specify the expressions for the |
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position of the top-left corner of the output (non-cropped) area. They |
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are evaluated for each frame. If the evaluated value is not valid, it |
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is approximated to the nearest valid value. |
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The default value of @var{x} is "(in_w-out_w)/2", and the default |
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value for @var{y} is "(in_h-out_h)/2", which set the cropped area at |
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the center of the input image. |
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The expression for @var{x} may depend on @var{y}, and the expression |
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for @var{y} may depend on @var{x}. |
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Follow some examples: |
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@example |
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# crop the central input area with size 100x100 |
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crop=100:100 |
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# crop the central input area with size 2/3 of the input video |
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"crop=2/3*in_w:2/3*in_h" |
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# crop the input video central square |
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crop=in_h |
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# delimit the rectangle with the top-left corner placed at position |
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# 100:100 and the right-bottom corner corresponding to the right-bottom |
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# corner of the input image. |
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crop=in_w-100:in_h-100:100:100 |
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# crop 10 pixels from the left and right borders, and 20 pixels from |
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# the top and bottom borders |
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"crop=in_w-2*10:in_h-2*20" |
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# keep only the bottom right quarter of the input image |
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"crop=in_w/2:in_h/2:in_w/2:in_h/2" |
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# crop height for getting Greek harmony |
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"crop=in_w:1/PHI*in_w" |
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# trembling effect |
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"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)" |
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# erratic camera effect depending on timestamp |
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"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)" |
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# set x depending on the value of y |
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"crop=in_w/2:in_h/2:y:10+10*sin(n/10)" |
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@end example |
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@section cropdetect |
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Auto-detect crop size. |
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Calculate necessary cropping parameters and prints the recommended |
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parameters through the logging system. The detected dimensions |
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correspond to the non-black area of the input video. |
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It accepts the syntax: |
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@example |
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cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]] |
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@end example |
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@table @option |
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@item limit |
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Threshold, which can be optionally specified from nothing (0) to |
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everything (255), defaults to 24. |
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@item round |
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Value which the width/height should be divisible by, defaults to |
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16. The offset is automatically adjusted to center the video. Use 2 to |
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get only even dimensions (needed for 4:2:2 video). 16 is best when |
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encoding to most video codecs. |
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@item reset |
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Counter that determines after how many frames cropdetect will reset |
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the previously detected largest video area and start over to detect |
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the current optimal crop area. Defaults to 0. |
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This can be useful when channel logos distort the video area. 0 |
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indicates never reset and return the largest area encountered during |
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playback. |
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@end table |
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@section drawbox |
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Draw a colored box on the input image. |
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It accepts the syntax: |
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@example |
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drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color} |
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@end example |
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@table @option |
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@item x, y |
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Specify the top left corner coordinates of the box. Default to 0. |
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@item width, height |
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Specify the width and height of the box, if 0 they are interpreted as |
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the input width and height. Default to 0. |
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@item color |
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Specify the color of the box to write, it can be the name of a color |
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(case insensitive match) or a 0xRRGGBB[AA] sequence. |
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@end table |
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Follow some examples: |
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@example |
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# draw a black box around the edge of the input image |
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drawbox |
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# draw a box with color red and an opacity of 50% |
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drawbox=10:20:200:60:red@@0.5" |
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@end example |
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@section fade |
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Apply fade-in/out effect to input video. |
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It accepts the parameters: |
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@var{type}:@var{start_frame}:@var{nb_frames} |
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@var{type} specifies if the effect type, can be either "in" for |
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fade-in, or "out" for a fade-out effect. |
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@var{start_frame} specifies the number of the start frame for starting |
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to apply the fade effect. |
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@var{nb_frames} specifies the number of frames for which the fade |
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effect has to last. At the end of the fade-in effect the output video |
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will have the same intensity as the input video, at the end of the |
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fade-out transition the output video will be completely black. |
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A few usage examples follow, usable too as test scenarios. |
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@example |
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# fade in first 30 frames of video |
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fade=in:0:30 |
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# fade out last 45 frames of a 200-frame video |
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fade=out:155:45 |
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# fade in first 25 frames and fade out last 25 frames of a 1000-frame video |
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fade=in:0:25, fade=out:975:25 |
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# make first 5 frames black, then fade in from frame 5-24 |
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fade=in:5:20 |
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@end example |
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@section drawtext |
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Draw text string or text from specified file on top of video using the |
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libfreetype library. |
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To enable compilation of this filter you need to configure FFmpeg with |
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@code{--enable-libfreetype}. |
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The filter also recognizes strftime() sequences in the provided text |
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and expands them accordingly. Check the documentation of strftime(). |
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The filter accepts parameters as a list of @var{key}=@var{value} pairs, |
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separated by ":". |
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The description of the accepted parameters follows. |
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@table @option |
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@item fontfile |
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The font file to be used for drawing text. Path must be included. |
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This parameter is mandatory. |
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@item text |
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The text string to be drawn. The text must be a sequence of UTF-8 |
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encoded characters. |
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This parameter is mandatory if no file is specified. |
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@item textfile |
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A text file containing text to be drawn. The text must be a sequence |
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of UTF-8 encoded characters |
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This parameter is mandatory if no text string is specified. |
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If both text and textfile are specified, an error is thrown. |
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@item x, y |
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The offsets where text will be drawn within the video frame. |
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Relative to the top/left border of the output image. |
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The default value of @var{x} and @var{y} is 0. |
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@item fontsize |
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The font size to be used for drawing text. |
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The default value of @var{size} is 16. |
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@item fontcolor |
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The color to be used for drawing fonts. |
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Either a string (e.g. "red") or in 0xRRGGBB[AA] format |
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(e.g. "0xff000033"), possibly followed by an alpha specifier. |
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The default value of @var{fontcolor} is "black". |
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@item boxcolor |
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The color to be used for drawing box around text. |
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Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format |
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(e.g. "0xff00ff"), possibly followed by an alpha specifier. |
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The default value of @var{bgcolor} is "white". |
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@item box |
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Used to draw a box around text using background color. |
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Value should be either 1 (enable) or 0 (disable). |
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The default value of @var{box} is 0. |
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@item ft_load_flags |
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Flags to be used for loading the fonts. |
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The flags map the corresponding flags supported by libfreetype, and are |
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a combination of the following values: |
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@table @var |
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@item default |
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@item no_scale |
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@item no_hinting |
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@item render |
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@item no_bitmap |
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@item vertical_layout |
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@item force_autohint |
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@item crop_bitmap |
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@item pedantic |
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@item ignore_global_advance_width |
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@item no_recurse |
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@item ignore_transform |
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@item monochrome |
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@item linear_design |
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@item no_autohint |
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@item end table |
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@end table |
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Default value is "render". |
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For more information consult the documentation for the FT_LOAD_* |
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libfreetype flags. |
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|
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@item tabsize |
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The size in number of spaces to use for rendering the tab. |
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Default value is 4. |
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@end table |
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For example the command: |
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@example |
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drawtext=fontfile=FreeSerif.ttf: text='Test Text': x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: boxcolor=red@@0.2: box=1" |
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@end example |
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|
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will draw 'Test Text' with font FreeSerif of size 24 at position |
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(100,50), text color is yellow, and draw a red box around text. Both |
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the text and the box have an opacity of 20%. |
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|
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Note that the double quotes are not necessary if spaces are not used |
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within the parameter list. |
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For more information about libfreetype, check: |
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@url{http://www.freetype.org/} |
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|
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@section fifo |
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Buffer input images and send them when they are requested. |
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|
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This filter is mainly useful when auto-inserted by the libavfilter |
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framework. |
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The filter does not take parameters. |
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@section format |
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|
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Convert the input video to one of the specified pixel formats. |
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Libavfilter will try to pick one that is supported for the input to |
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the next filter. |
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The filter accepts a list of pixel format names, separated by ":", |
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for example "yuv420p:monow:rgb24". |
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Some examples follow: |
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@example |
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# convert the input video to the format "yuv420p" |
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format=yuv420p |
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|
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# convert the input video to any of the formats in the list |
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format=yuv420p:yuv444p:yuv410p |
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@end example |
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|
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@anchor{frei0r} |
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@section frei0r |
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|
|
Apply a frei0r effect to the input video. |
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|
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To enable compilation of this filter you need to install the frei0r |
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header and configure FFmpeg with --enable-frei0r. |
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|
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The filter supports the syntax: |
|
@example |
|
@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}] |
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@end example |
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@var{filter_name} is the name to the frei0r effect to load. If the |
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environment variable @env{FREI0R_PATH} is defined, the frei0r effect |
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is searched in each one of the directories specified by the colon |
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separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r |
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paths, which are in this order: @file{HOME/.frei0r-1/lib/}, |
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@file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}. |
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@var{param1}, @var{param2}, ... , @var{paramN} specify the parameters |
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for the frei0r effect. |
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|
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A frei0r effect parameter can be a boolean (whose values are specified |
|
with "y" and "n"), a double, a color (specified by the syntax |
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@var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float |
|
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}, |
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@var{X} and @var{Y} being float numbers) and a string. |
|
|
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The number and kind of parameters depend on the loaded effect. If an |
|
effect parameter is not specified the default value is set. |
|
|
|
Some examples follow: |
|
@example |
|
# apply the distort0r effect, set the first two double parameters |
|
frei0r=distort0r:0.5:0.01 |
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|
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# apply the colordistance effect, takes a color as first parameter |
|
frei0r=colordistance:0.2/0.3/0.4 |
|
frei0r=colordistance:violet |
|
frei0r=colordistance:0x112233 |
|
|
|
# apply the perspective effect, specify the top left and top right |
|
# image positions |
|
frei0r=perspective:0.2/0.2:0.8/0.2 |
|
@end example |
|
|
|
For more information see: |
|
@url{http://piksel.org/frei0r} |
|
|
|
@section gradfun |
|
|
|
Fix the banding artifacts that are sometimes introduced into nearly flat |
|
regions by truncation to 8bit colordepth. |
|
Interpolate the gradients that should go where the bands are, and |
|
dither them. |
|
|
|
The filter takes two optional parameters, separated by ':': |
|
@var{strength}:@var{radius} |
|
|
|
@var{strength} is the maximum amount by which the filter will change |
|
any one pixel. Also the threshold for detecting nearly flat |
|
regions. Acceptable values range from .51 to 255, default value is |
|
1.2, out-of-range values will be clipped to the valid range. |
|
|
|
@var{radius} is the neighborhood to fit the gradient to. A larger |
|
radius makes for smoother gradients, but also prevents the filter from |
|
modifying the pixels near detailed regions. Acceptable values are |
|
8-32, default value is 16, out-of-range values will be clipped to the |
|
valid range. |
|
|
|
@example |
|
# default parameters |
|
gradfun=1.2:16 |
|
|
|
# omitting radius |
|
gradfun=1.2 |
|
@end example |
|
|
|
@section hflip |
|
|
|
Flip the input video horizontally. |
|
|
|
For example to horizontally flip the video in input with |
|
@file{ffmpeg}: |
|
@example |
|
ffmpeg -i in.avi -vf "hflip" out.avi |
|
@end example |
|
|
|
@section hqdn3d |
|
|
|
High precision/quality 3d denoise filter. This filter aims to reduce |
|
image noise producing smooth images and making still images really |
|
still. It should enhance compressibility. |
|
|
|
It accepts the following optional parameters: |
|
@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp} |
|
|
|
@table @option |
|
@item luma_spatial |
|
a non-negative float number which specifies spatial luma strength, |
|
defaults to 4.0 |
|
|
|
@item chroma_spatial |
|
a non-negative float number which specifies spatial chroma strength, |
|
defaults to 3.0*@var{luma_spatial}/4.0 |
|
|
|
@item luma_tmp |
|
a float number which specifies luma temporal strength, defaults to |
|
6.0*@var{luma_spatial}/4.0 |
|
|
|
@item chroma_tmp |
|
a float number which specifies chroma temporal strength, defaults to |
|
@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial} |
|
@end table |
|
|
|
@section noformat |
|
|
|
Force libavfilter not to use any of the specified pixel formats for the |
|
input to the next filter. |
|
|
|
The filter accepts a list of pixel format names, separated by ":", |
|
for example "yuv420p:monow:rgb24". |
|
|
|
Some examples follow: |
|
@example |
|
# force libavfilter to use a format different from "yuv420p" for the |
|
# input to the vflip filter |
|
noformat=yuv420p,vflip |
|
|
|
# convert the input video to any of the formats not contained in the list |
|
noformat=yuv420p:yuv444p:yuv410p |
|
@end example |
|
|
|
@section null |
|
|
|
Pass the video source unchanged to the output. |
|
|
|
@section ocv |
|
|
|
Apply video transform using libopencv. |
|
|
|
To enable this filter install libopencv library and headers and |
|
configure FFmpeg with --enable-libopencv. |
|
|
|
The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}. |
|
|
|
@var{filter_name} is the name of the libopencv filter to apply. |
|
|
|
@var{filter_params} specifies the parameters to pass to the libopencv |
|
filter. If not specified the default values are assumed. |
|
|
|
Refer to the official libopencv documentation for more precise |
|
informations: |
|
@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html} |
|
|
|
Follows the list of supported libopencv filters. |
|
|
|
@anchor{dilate} |
|
@subsection dilate |
|
|
|
Dilate an image by using a specific structuring element. |
|
This filter corresponds to the libopencv function @code{cvDilate}. |
|
|
|
It accepts the parameters: @var{struct_el}:@var{nb_iterations}. |
|
|
|
@var{struct_el} represents a structuring element, and has the syntax: |
|
@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape} |
|
|
|
@var{cols} and @var{rows} represent the number of colums and rows of |
|
the structuring element, @var{anchor_x} and @var{anchor_y} the anchor |
|
point, and @var{shape} the shape for the structuring element, and |
|
can be one of the values "rect", "cross", "ellipse", "custom". |
|
|
|
If the value for @var{shape} is "custom", it must be followed by a |
|
string of the form "=@var{filename}". The file with name |
|
@var{filename} is assumed to represent a binary image, with each |
|
printable character corresponding to a bright pixel. When a custom |
|
@var{shape} is used, @var{cols} and @var{rows} are ignored, the number |
|
or columns and rows of the read file are assumed instead. |
|
|
|
The default value for @var{struct_el} is "3x3+0x0/rect". |
|
|
|
@var{nb_iterations} specifies the number of times the transform is |
|
applied to the image, and defaults to 1. |
|
|
|
Follow some example: |
|
@example |
|
# use the default values |
|
ocv=dilate |
|
|
|
# dilate using a structuring element with a 5x5 cross, iterate two times |
|
ocv=dilate=5x5+2x2/cross:2 |
|
|
|
# read the shape from the file diamond.shape, iterate two times |
|
# the file diamond.shape may contain a pattern of characters like this: |
|
# * |
|
# *** |
|
# ***** |
|
# *** |
|
# * |
|
# the specified cols and rows are ignored (but not the anchor point coordinates) |
|
ocv=0x0+2x2/custom=diamond.shape:2 |
|
@end example |
|
|
|
@subsection erode |
|
|
|
Erode an image by using a specific structuring element. |
|
This filter corresponds to the libopencv function @code{cvErode}. |
|
|
|
The filter accepts the parameters: @var{struct_el}:@var{nb_iterations}, |
|
with the same meaning and use of those of the dilate filter |
|
(@pxref{dilate}). |
|
|
|
@subsection smooth |
|
|
|
Smooth the input video. |
|
|
|
The filter takes the following parameters: |
|
@var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}. |
|
|
|
@var{type} is the type of smooth filter to apply, and can be one of |
|
the following values: "blur", "blur_no_scale", "median", "gaussian", |
|
"bilateral". The default value is "gaussian". |
|
|
|
@var{param1}, @var{param2}, @var{param3}, and @var{param4} are |
|
parameters whose meanings depend on smooth type. @var{param1} and |
|
@var{param2} accept integer positive values or 0, @var{param3} and |
|
@var{param4} accept float values. |
|
|
|
The default value for @var{param1} is 3, the default value for the |
|
other parameters is 0. |
|
|
|
These parameters correspond to the parameters assigned to the |
|
libopencv function @code{cvSmooth}. |
|
|
|
@section overlay |
|
|
|
Overlay one video on top of another. |
|
|
|
It takes two inputs and one output, the first input is the "main" |
|
video on which the second input is overlayed. |
|
|
|
It accepts the parameters: @var{x}:@var{y}. |
|
|
|
@var{x} is the x coordinate of the overlayed video on the main video, |
|
@var{y} is the y coordinate. The parameters are expressions containing |
|
the following parameters: |
|
|
|
@table @option |
|
@item main_w, main_h |
|
main input width and height |
|
|
|
@item W, H |
|
same as @var{main_w} and @var{main_h} |
|
|
|
@item overlay_w, overlay_h |
|
overlay input width and height |
|
|
|
@item w, h |
|
same as @var{overlay_w} and @var{overlay_h} |
|
@end table |
|
|
|
Be aware that frames are taken from each input video in timestamp |
|
order, hence, if their initial timestamps differ, it is a a good idea |
|
to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to |
|
have them begin in the same zero timestamp, as it does the example for |
|
the @var{movie} filter. |
|
|
|
Follow some examples: |
|
@example |
|
# draw the overlay at 10 pixels from the bottom right |
|
# corner of the main video. |
|
overlay=main_w-overlay_w-10:main_h-overlay_h-10 |
|
|
|
# insert a transparent PNG logo in the bottom left corner of the input |
|
movie=logo.png [logo]; |
|
[in][logo] overlay=10:main_h-overlay_h-10 [out] |
|
|
|
# insert 2 different transparent PNG logos (second logo on bottom |
|
# right corner): |
|
movie=logo1.png [logo1]; |
|
movie=logo2.png [logo2]; |
|
[in][logo1] overlay=10:H-h-10 [in+logo1]; |
|
[in+logo1][logo2] overlay=W-w-10:H-h-10 [out] |
|
|
|
# add a transparent color layer on top of the main video, |
|
# WxH specifies the size of the main input to the overlay filter |
|
color=red@.3:WxH [over]; [in][over] overlay [out] |
|
@end example |
|
|
|
You can chain togheter more overlays but the efficiency of such |
|
approach is yet to be tested. |
|
|
|
@section pad |
|
|
|
Add paddings to the input image, and places the original input at the |
|
given coordinates @var{x}, @var{y}. |
|
|
|
It accepts the following parameters: |
|
@var{width}:@var{height}:@var{x}:@var{y}:@var{color}. |
|
|
|
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 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 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 |
|
|
|
For example: |
|
|
|
@example |
|
# Add paddings with color "violet" to the input video. Output video |
|
# size is 640x480, the top-left corner of the input video is placed at |
|
# row 0, column 40. |
|
pad=640:480:0:40:violet |
|
@end example |
|
|
|
@section pixdesctest |
|
|
|
Pixel format descriptor test filter, mainly useful for internal |
|
testing. The output video should be equal to the input video. |
|
|
|
For example: |
|
@example |
|
format=monow, pixdesctest |
|
@end example |
|
|
|
can be used to test the monowhite pixel format descriptor definition. |
|
|
|
@section scale |
|
|
|
Scale the input video to @var{width}:@var{height} and/or convert the image format. |
|
|
|
For example the command: |
|
|
|
@example |
|
./ffmpeg -i in.avi -vf "scale=200:100" out.avi |
|
@end example |
|
|
|
will scale the input video to a size of 200x100. |
|
|
|
If the input image format is different from the format requested by |
|
the next filter, the scale filter will convert the input to the |
|
requested format. |
|
|
|
If the value for @var{width} or @var{height} is 0, the respective input |
|
size is used for the output. |
|
|
|
If the value for @var{width} or @var{height} is -1, the scale filter will |
|
use, for the respective output size, a value that maintains the aspect |
|
ratio of the input image. |
|
|
|
The default value of @var{width} and @var{height} is 0. |
|
|
|
@section setpts |
|
|
|
Change the PTS (presentation timestamp) of the input video frames. |
|
|
|
Accept in input an expression evaluated through the eval API, which |
|
can contain the following constants: |
|
|
|
@table @option |
|
@item PTS |
|
the presentation timestamp in input |
|
|
|
@item PI |
|
Greek PI |
|
|
|
@item PHI |
|
golden ratio |
|
|
|
@item E |
|
Euler number |
|
|
|
@item N |
|
the count of the input frame, starting from 0. |
|
|
|
@item STARTPTS |
|
the PTS of the first video frame |
|
|
|
@item INTERLACED |
|
tell if the current frame is interlaced |
|
|
|
@item POS |
|
original position in the file of the frame, or undefined if undefined |
|
for the current frame |
|
|
|
@item PREV_INPTS |
|
previous input PTS |
|
|
|
@item PREV_OUTPTS |
|
previous output PTS |
|
|
|
@end table |
|
|
|
Some examples follow: |
|
|
|
@example |
|
# start counting PTS from zero |
|
setpts=PTS-STARTPTS |
|
|
|
# fast motion |
|
setpts=0.5*PTS |
|
|
|
# slow motion |
|
setpts=2.0*PTS |
|
|
|
# fixed rate 25 fps |
|
setpts=N/(25*TB) |
|
|
|
# fixed rate 25 fps with some jitter |
|
setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))' |
|
@end example |
|
|
|
@section settb |
|
|
|
Set the timebase to use for the output frames timestamps. |
|
It is mainly useful for testing timebase configuration. |
|
|
|
It accepts in input an arithmetic expression representing a rational. |
|
The expression can contain the constants "PI", "E", "PHI", "AVTB" (the |
|
default timebase), and "intb" (the input timebase). |
|
|
|
The default value for the input is "intb". |
|
|
|
Follow some examples. |
|
|
|
@example |
|
# set the timebase to 1/25 |
|
settb=1/25 |
|
|
|
# set the timebase to 1/10 |
|
settb=0.1 |
|
|
|
#set the timebase to 1001/1000 |
|
settb=1+0.001 |
|
|
|
#set the timebase to 2*intb |
|
settb=2*intb |
|
|
|
#set the default timebase value |
|
settb=AVTB |
|
@end example |
|
|
|
@section slicify |
|
|
|
Pass the images of input video on to next video filter as multiple |
|
slices. |
|
|
|
@example |
|
./ffmpeg -i in.avi -vf "slicify=32" out.avi |
|
@end example |
|
|
|
The filter accepts the slice height as parameter. If the parameter is |
|
not specified it will use the default value of 16. |
|
|
|
Adding this in the beginning of filter chains should make filtering |
|
faster due to better use of the memory cache. |
|
|
|
@section transpose |
|
|
|
Transpose rows with columns in the input video and optionally flip it. |
|
|
|
It accepts a parameter representing an integer, which can assume the |
|
values: |
|
|
|
@table @samp |
|
@item 0 |
|
Rotate by 90 degrees counterclockwise and vertically flip (default), that is: |
|
@example |
|
L.R L.l |
|
. . -> . . |
|
l.r R.r |
|
@end example |
|
|
|
@item 1 |
|
Rotate by 90 degrees clockwise, that is: |
|
@example |
|
L.R l.L |
|
. . -> . . |
|
l.r r.R |
|
@end example |
|
|
|
@item 2 |
|
Rotate by 90 degrees counterclockwise, that is: |
|
@example |
|
L.R R.r |
|
. . -> . . |
|
l.r L.l |
|
@end example |
|
|
|
@item 3 |
|
Rotate by 90 degrees clockwise and vertically flip, that is: |
|
@example |
|
L.R r.R |
|
. . -> . . |
|
l.r l.L |
|
@end example |
|
@end table |
|
|
|
@section unsharp |
|
|
|
Sharpen or blur the input video. |
|
|
|
It accepts the following parameters: |
|
@var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount} |
|
|
|
Negative values for the amount will blur the input video, while positive |
|
values will sharpen. All parameters are optional and default to the |
|
equivalent of the string '5:5:1.0:0:0:0.0'. |
|
|
|
@table @option |
|
|
|
@item luma_msize_x |
|
Set the luma matrix horizontal size. It can be an integer between 3 |
|
and 13, default value is 5. |
|
|
|
@item luma_msize_y |
|
Set the luma matrix vertical size. It can be an integer between 3 |
|
and 13, default value is 5. |
|
|
|
@item luma_amount |
|
Set the luma effect strength. It can be a float number between -2.0 |
|
and 5.0, default value is 1.0. |
|
|
|
@item chroma_msize_x |
|
Set the chroma matrix horizontal size. It can be an integer between 3 |
|
and 13, default value is 0. |
|
|
|
@item chroma_msize_y |
|
Set the chroma matrix vertical size. It can be an integer between 3 |
|
and 13, default value is 0. |
|
|
|
@item luma_amount |
|
Set the chroma effect strength. It can be a float number between -2.0 |
|
and 5.0, default value is 0.0. |
|
|
|
@end table |
|
|
|
@example |
|
# Strong luma sharpen effect parameters |
|
unsharp=7:7:2.5 |
|
|
|
# Strong blur of both luma and chroma parameters |
|
unsharp=7:7:-2:7:7:-2 |
|
|
|
# Use the default values with @command{ffmpeg} |
|
./ffmpeg -i in.avi -vf "unsharp" out.mp4 |
|
@end example |
|
|
|
@section vflip |
|
|
|
Flip the input video vertically. |
|
|
|
@example |
|
./ffmpeg -i in.avi -vf "vflip" out.avi |
|
@end example |
|
|
|
@section yadif |
|
|
|
Deinterlace the input video ("yadif" means "yet another deinterlacing |
|
filter"). |
|
|
|
It accepts the optional parameters: @var{mode}:@var{parity}. |
|
|
|
@var{mode} specifies the interlacing mode to adopt, accepts one of the |
|
following values: |
|
|
|
@table @option |
|
@item 0 |
|
output 1 frame for each frame |
|
@item 1 |
|
output 1 frame for each field |
|
@item 2 |
|
like 0 but skips spatial interlacing check |
|
@item 3 |
|
like 1 but skips spatial interlacing check |
|
@end table |
|
|
|
Default value is 0. |
|
|
|
@var{parity} specifies the picture field parity assumed for the input |
|
interlaced video, accepts one of the following values: |
|
|
|
@table @option |
|
@item 0 |
|
assume bottom field first |
|
@item 1 |
|
assume top field first |
|
@item -1 |
|
enable automatic detection |
|
@end table |
|
|
|
Default value is -1. |
|
If interlacing is unknown or decoder does not export this information, |
|
top field first will be assumed. |
|
|
|
@c man end VIDEO FILTERS |
|
|
|
@chapter Video Sources |
|
@c man begin VIDEO SOURCES |
|
|
|
Below is a description of the currently available video sources. |
|
|
|
@section buffer |
|
|
|
Buffer video frames, and make them available to the filter chain. |
|
|
|
This source is mainly intended for a programmatic use, in particular |
|
through the interface defined in @file{libavfilter/vsrc_buffer.h}. |
|
|
|
It accepts the following parameters: |
|
@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den} |
|
|
|
All the parameters need to be explicitely defined. |
|
|
|
Follows the list of the accepted parameters. |
|
|
|
@table @option |
|
|
|
@item width, height |
|
Specify the width and height of the buffered video frames. |
|
|
|
@item pix_fmt_string |
|
A string representing the pixel format of the buffered video frames. |
|
It may be a number corresponding to a pixel format, or a pixel format |
|
name. |
|
|
|
@item timebase_num, timebase_den |
|
Specify numerator and denomitor of the timebase assumed by the |
|
timestamps of the buffered frames. |
|
|
|
@item sample_aspect_ratio.num, sample_aspect_ratio.den |
|
Specify numerator and denominator of the sample aspect ratio assumed |
|
by the video frames. |
|
@end table |
|
|
|
For example: |
|
@example |
|
buffer=320:240:yuv410p:1:24:1:1 |
|
@end example |
|
|
|
will instruct the source to accept video frames with size 320x240 and |
|
with format "yuv410p", assuming 1/24 as the timestamps timebase and |
|
square pixels (1:1 sample aspect ratio). |
|
Since the pixel format with name "yuv410p" corresponds to the number 6 |
|
(check the enum PixelFormat definition in @file{libavutil/pixfmt.h}), |
|
this example corresponds to: |
|
@example |
|
buffer=320:240:6:1:24 |
|
@end example |
|
|
|
@section color |
|
|
|
Provide an uniformly colored input. |
|
|
|
It accepts the following parameters: |
|
@var{color}:@var{frame_size}:@var{frame_rate} |
|
|
|
Follows the description of the accepted parameters. |
|
|
|
@table @option |
|
|
|
@item color |
|
Specify the color of the source. It can be the name of a color (case |
|
insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an |
|
alpha specifier. The default value is "black". |
|
|
|
@item frame_size |
|
Specify the size of the sourced video, it may be a string of the form |
|
@var{width}x@var{heigth}, or the name of a size abbreviation. The |
|
default value is "320x240". |
|
|
|
@item frame_rate |
|
Specify the frame rate of the sourced video, as the number of frames |
|
generated per second. It has to be a string in the format |
|
@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float |
|
number or a valid video frame rate abbreviation. The default value is |
|
"25". |
|
|
|
@end table |
|
|
|
For example the following graph description will generate a red source |
|
with an opacity of 0.2, with size "qcif" and a frame rate of 10 |
|
frames per second, which will be overlayed over the source connected |
|
to the pad with identifier "in". |
|
|
|
@example |
|
"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]" |
|
@end example |
|
|
|
@section movie |
|
|
|
Read a video stream from a movie container. |
|
|
|
It accepts the syntax: @var{movie_name}[:@var{options}] where |
|
@var{movie_name} is the name of the resource to read (not necessarily |
|
a file but also a device or a stream accessed through some protocol), |
|
and @var{options} is an optional sequence of @var{key}=@var{value} |
|
pairs, separated by ":". |
|
|
|
The description of the accepted options follows. |
|
|
|
@table @option |
|
|
|
@item format_name, f |
|
Specifies the format assumed for the movie to read, and can be either |
|
the name of a container or an input device. If not specified the |
|
format is guessed from @var{movie_name} or by probing. |
|
|
|
@item seek_point, sp |
|
Specifies the seek point in seconds, the frames will be output |
|
starting from this seek point, the parameter is evaluated with |
|
@code{av_strtod} so the numerical value may be suffixed by an IS |
|
postfix. Default value is "0". |
|
|
|
@item stream_index, si |
|
Specifies the index of the video stream to read. If the value is -1, |
|
the best suited video stream will be automatically selected. Default |
|
value is "-1". |
|
|
|
@end table |
|
|
|
This filter allows to overlay a second video on top of main input of |
|
a filtergraph as shown in this graph: |
|
@example |
|
input -----------> deltapts0 --> overlay --> output |
|
^ |
|
| |
|
movie --> scale--> deltapts1 -------+ |
|
@end example |
|
|
|
Some examples follow: |
|
@example |
|
# skip 3.2 seconds from the start of the avi file in.avi, and overlay it |
|
# on top of the input labelled as "in". |
|
movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie]; |
|
[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] |
|
|
|
# read from a video4linux2 device, and overlay it on top of the input |
|
# labelled as "in" |
|
movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie]; |
|
[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] |
|
|
|
@end example |
|
|
|
@section nullsrc |
|
|
|
Null video source, never return images. It is mainly useful as a |
|
template and to be employed in analysis / debugging tools. |
|
|
|
It accepts as optional parameter a string of the form |
|
@var{width}:@var{height}:@var{timebase}. |
|
|
|
@var{width} and @var{height} specify the size of the configured |
|
source. The default values of @var{width} and @var{height} are |
|
respectively 352 and 288 (corresponding to the CIF size format). |
|
|
|
@var{timebase} specifies an arithmetic expression representing a |
|
timebase. The expression can contain the constants "PI", "E", "PHI", |
|
"AVTB" (the default timebase), and defaults to the value "AVTB". |
|
|
|
@section frei0r_src |
|
|
|
Provide a frei0r source. |
|
|
|
To enable compilation of this filter you need to install the frei0r |
|
header and configure FFmpeg with --enable-frei0r. |
|
|
|
The source supports the syntax: |
|
@example |
|
@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}] |
|
@end example |
|
|
|
@var{size} is the size of the video to generate, may be a string of the |
|
form @var{width}x@var{height} or a frame size abbreviation. |
|
@var{rate} is the rate of the video to generate, may be a string of |
|
the form @var{num}/@var{den} or a frame rate abbreviation. |
|
@var{src_name} is the name to the frei0r source to load. For more |
|
information regarding frei0r and how to set the parameters read the |
|
section "frei0r" (@pxref{frei0r}) in the description of the video |
|
filters. |
|
|
|
Some examples follow: |
|
@example |
|
# generate a frei0r partik0l source with size 200x200 and framerate 10 |
|
# which is overlayed on the overlay filter main input |
|
frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay |
|
@end example |
|
|
|
@c man end VIDEO SOURCES |
|
|
|
@chapter Video Sinks |
|
@c man begin VIDEO SINKS |
|
|
|
Below is a description of the currently available video sinks. |
|
|
|
@section nullsink |
|
|
|
Null video sink, do absolutely nothing with the input video. It is |
|
mainly useful as a template and to be employed in analysis / debugging |
|
tools. |
|
|
|
@c man end VIDEO SINKS |
|
|
|
|