Anlmdn

Audio Single output Transform

Reduce broadband noise from stream using Non-Local Means.

FFmpeg filter: anlmdn — 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   = $audio->addFilter(new Anlmdn(…));
$result = $node->outputs()[0];

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

$result = $audio->apply(new Anlmdn(…));

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	1.0E-5	1.0E-5–10000	set denoising strength
patch	int	2000	1000–100000	set patch duration
research	int	6000	2000–300000	set research duration
output	AnlmdnMode	o	i, o, n	set output mode
smooth	float	11	1–1000	set smooth factor

FFmpeg also names these options (use the parameter shown above): s → strength, p → patch, r → research, o → output, m → smooth.

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