Convolution

Video Single output Transform

Apply convolution filter.

FFmpeg filter: convolution — the official reference.

Add it to a graph. The explicit form works for every filter — bind it to its input and read the result from outputs():

$node   = $video->addFilter(new Convolution(…));
$result = $node->outputs()[0];

Shorthand. Single-output filters can skip the node — apply() returns the result stream directly:

$result = $video->apply(new Convolution(…));

When to use it

TODO — when this filter shines: what it’s the right tool for, what to reach for instead when it isn’t, and how it composes with neighbouring filters.

How to use it

TODO — prose: how the filter actually works and what its key parameters mean (the explanation FFmpeg’s terse option help omits).

Examples

TODO — runnable PHP, with the equivalent ffmpeg CLI alongside.

Gotchas

TODO

See also

TODO

Parameters

Parameter	Type	Default	Range / values	Description
_0m	string	0 0 0 0 1 0 0 0 0	—	set matrix for 1st plane
_1m	string	0 0 0 0 1 0 0 0 0	—	set matrix for 2nd plane
_2m	string	0 0 0 0 1 0 0 0 0	—	set matrix for 3rd plane
_3m	string	0 0 0 0 1 0 0 0 0	—	set matrix for 4th plane
_0rdiv	float	0	≥ 0	set rdiv for 1st plane
_1rdiv	float	0	≥ 0	set rdiv for 2nd plane
_2rdiv	float	0	≥ 0	set rdiv for 3rd plane
_3rdiv	float	0	≥ 0	set rdiv for 4th plane
_0bias	float	0	≥ 0	set bias for 1st plane
_1bias	float	0	≥ 0	set bias for 2nd plane
_2bias	float	0	≥ 0	set bias for 3rd plane
_3bias	float	0	≥ 0	set bias for 4th plane
_0mode	ConvolutionMode	square	square, row, column	set matrix mode for 1st plane
_1mode	ConvolutionMode	square	square, row, column	set matrix mode for 2nd plane
_2mode	ConvolutionMode	square	square, row, column	set matrix mode for 3rd plane
_3mode	ConvolutionMode	square	square, row, column	set matrix mode for 4th plane

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Maps to FFmpeg’s convolution filter. Verified against ffmpeg n7.1.1.