Acompressor

Audio Single output Transform

Audio compressor.

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

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

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

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
level_in	float	1	0.015625–64	set input gain
mode	AcompressorMode	downward	downward, upward	set mode
threshold	float	0.125	0.000976563–1	set threshold
ratio	float	2	1–20	set ratio
attack	float	20	0.01–2000	set attack
release	float	250	0.01–9000	set release
makeup	float	1	1–64	set make up gain
knee	float	2.82843	1–8	set knee
link	AcompressorLink	average	average, maximum	set link type
detection	AcompressorDetection	rms	peak, rms	set detection
level_sc	float	1	0.015625–64	set sidechain gain
mix	float	1	0–1	set mix

---

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