Afireqsrc

Audio Single output Source

Generate a FIR equalizer coefficients audio stream.

FFmpeg filter: afireqsrc — the official reference.

Generate a stream. Afireqsrc is a source — it has no input, so you create a stream from it rather than applying it to one:

$audio = \FFmpeg\AudioStream::generate(new Afireqsrc(…));

apply() and addFilter() do not apply to source filters (there is nothing to attach them to).

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
preset	AfireqsrcPreset	flat	custom, flat, acoustic, bass, beats, classic, clear, deep bass, …	set equalizer preset
gains	string	0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0	—	set gain values per band
bands	string	25 40 63 100 160 250 400 630 1000 1600 2500 4000 6300 10000 16000 24000	—	set central frequency values per band
taps	int	4096	16–65535	set number of taps
sample_rate	int	44100	≥ 1	set sample rate
nb_samples	int	1024	≥ 1	set the number of samples per requested frame
interp	AfireqsrcInterp	linear	linear, cubic	set the interpolation
phase	AfireqsrcPhase	min	linear, min	set the phase

FFmpeg also names these options (use the parameter shown above): p → preset, g → gains, b → bands, t → taps, r → sample_rate, n → nb_samples, i → interp, h → phase.

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