Thanks for your response. I understand the problem of clock drift when we have several audio hardware devices (with different qwartz). But here, it's a pity that the null video driver has an independent clock... Concerning pipewire, for now it doesn't work with our particular application (no sound), but it seems to evolve quickly. I haven't tried jack for now, but if it depends on pulseaudio, won't I have the same problem?
Renaud Le jeu. 4 févr. 2021 à 00:20, Alexander E. Patrakov <patra...@gmail.com> a écrit : > чт, 4 февр. 2021 г. в 03:10, Renaud GHIA <rg...@tixeo.com>: > >> Thank you for the tip. >> Now I am sure that resampling does not apply (see below). >> But unfortunately pulseaudio always consumes 30% of one CPU core! >> > > The reason is that you are using module-loopback. Due to a potential > difference between the clocks on the null sink and on the real sound card > (even though both report 44100 Hz), it always has to resample in order to > correct for the clock skew. If you don't understand, here is an analogy: > you have two mechanical watches. Even though both claim that their hour > hand makes one full circle every 12 hours, in fact, if left unattended, > they will diverge over time. There is no way to avoid that, except by > moving to Jack or PipeWire which simply don't introduce a null sink with an > independent clock. > > If you decide to stay on PulseAudio, you can tweak the resampling method. > The default, speex-float-1, is light on the CPU resources and should > produce no distortions detectable by human ear on typical speech and music. > It does produce easily detectable distortions on specifically crafted > signals. If you want to make sure that the resampler is transparent no > matter what is thrown at it, use speex-float-5. There is no point in going > higher than that. > > -- > Alexander E. Patrakov > CV: http://u.pc.cd/wT8otalK > _______________________________________________ > pulseaudio-discuss mailing list > pulseaudio-discuss@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss >
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