Sinc

Audio Single output Source

Generate a sinc kaiser-windowed low-pass, high-pass, band-pass, or band-reject FIR coefficients.

FFmpeg filter: sinc — the official reference.

Generate a stream. Sinc 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 Sinc(…));

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
sample_rate	int	44100	≥ 1	set sample rate
nb_samples	int	1024	≥ 1	set the number of samples per requested frame
hp	float	0	≥ 0	set high-pass filter frequency
lp	float	0	≥ 0	set low-pass filter frequency
phase	float	50	0–100	set filter phase response
beta	float	-1	-1–256	set kaiser window beta
att	float	120	40–180	set stop-band attenuation
round	bool	false	—	enable rounding
hptaps	int	0	0–32768	set number of taps for high-pass filter
lptaps	int	0	0–32768	set number of taps for low-pass filter

FFmpeg also names these options (use the parameter shown above): r → sample_rate, n → nb_samples.

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