Afir

Audio Single output Transform

Apply Finite Impulse Response filter with supplied coefficients in additional stream(s).

FFmpeg filter: afir — the official reference.

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

$node   = $audio->addFilter(new Afir(…), [$other]);
$result = $node->outputs()[0];

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

$result = $audio->apply(new Afir(…), $other);

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
dry	float	1	0–10	set dry gain
wet	float	1	0–10	set wet gain
length	float	1	0–1	set IR length
gtype	AfirGtype	peak	none, peak, dc, gn, ac, rms	set IR auto gain type
irnorm	float	1	-1–2	set IR norm
irlink	bool	true	—	set IR link
irgain	float	1	0–1	set IR gain
irfmt	AfirIrfmt	input	mono, input	set IR format
maxir	float	30	0.1–60	set max IR length
response	bool	false	—	show IR frequency response
channel	int	0	0–1024	set IR channel to display frequency response
size	string	hd720	—	set video size
rate	string	25	—	set video rate
minp	int	8192	1–65536	set min partition size
maxp	int	8192	8–65536	set max partition size
nbirs	int	1	1–32	set number of input IRs
ir	int	0	0–31	select IR
precision	AfirPrecision	auto	auto, float, double	set processing precision
irload	AfirIrload	init	init, access	set IR loading type

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