[pulseaudio-discuss] Why are we checking various sample rates?

[Raymond Yau]

2012-11-30 下午5:01 於 "David Henningsson" <david.henningsson at canonical.com>
寫道：
>
> Hi,
>
> I'm researching a bug where some set of USB speakers stopped working,
probably in 2.x. The peculiar thing about this sound card is that seems to
only work at a sample rate of 46875 Hz.
>
> So in 2.x, the probe fails with
> "E: [pulseaudio] alsa-sink.c: Failed to find any supported sample
rates.", whereas in an earlier version, it would just happily work at 46875
Hz instead, as I understand it.
>
> So my first question is; why do we check all these rates, when we end up
just alternating between default-sample-rate (44100 Hz) and
alternate-sample-rate (48000 Hz) anyway?
> And second, can we try not to fail if we can't find any supported sample
rates, so we can fix this regression?

http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/src/daemon/daemon-conf.c?id=5bcfd2b630ae56c97348edc93c4c237f71b24283

Since pulseaudio 2.0 require sound card support sample rate which are
multiple of 4000 and 11025

>
> For reference, this is the bug (with pulse verbose logs in it):
>
> https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1074783
>
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