Gradfun

Video Single output Transform

Debands video quickly using gradients.

FFmpeg filter: gradfun — 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 Gradfun(…));
$result = $node->outputs()[0];

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

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

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
strength	float	1.2	0.51–64	The maximum amount by which the filter will change any one pixel.
radius	int	16	4–32	The neighborhood to fit the gradient to.

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