[pulseaudio-discuss] R: New equalizer module (module-eqpro-sink), some questions

Georg Chini georg at chini.tk
Sat Apr 20 10:20:48 UTC 2019

On 20.04.19 12:14, Alexander E. Patrakov wrote:
> [forgot to CC the list - sorry for any duplicates]
> сб, 20 апр. 2019 г. в 14:39, Georg Chini <georg at chini.tk>:
>> I think using malloc() when a parameter changes is not interfering
>> with real-time operation because the filter must be reset after
>> a parameter change anyway.
> The parameter changes allowed during the runtime are not expected to
> need a filter reset. In-place rebuild - yes, reset - no. The filtered
> audio should smoothly follow gradual changes of the filter parameters.
> Many LADSPA plugins actually implement internal smoothing of parameter
> value changes, or even internally keep two filter versions and
> interpolate between them, in order to avoid clicks, because such
> gradual changes are an expected thing in pro audio workflows.
Within PA, the filter must at least be rewound when a parameter changes.
Because rewinding is not part of the standard, the best we can do is to
reset the filter in that case by calling deactivate() and activate().

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