[pulseaudio-discuss] cracks and pops with intelHDA

[Lennart Poettering]

On Sat, 12.01.08 13:49, Ritesh Kumar (ritesh at cs.unc.edu) wrote:

> > I had no such  cracks and pops earlier with alsa+dmix running at 192Khz. I
> > had even added the speex resampler to alsa+dmix and faced no problems. The
> > CPU usage for the audio application used to go up quite a bit (14%) due to
> > the resampling but that's expected. However I did notice a good amount of
> > latency then with games which I played through alsa-oss. I won't say padsp
> > is perfect but it is surely much better latency wise.
> > Please note that the applications I am using send sound to pulseaudio
> > using either gst-pulse or alsa-pulse... and I saw cracks and pops with both.
> >
> >
> I am running pulseaudio without any cracks and pops now. The difference is
> that now the intel HDA sink runs at 48kHz instead of 192kHz. However, the
> cracks and pops come back after a suspend-to-ram.
> I also removed fifo scheduling... (back to the default pulse 0.9.8 setup;
> nicing only)... it didn't seem to have an effect.

> This brings up two questions:
> 1) Can suspend-to-ram cause timing problems in pulseaudio? If not then the
> kernel's USB audio driver seems to be doing something fishy here.

Generally PA should survive STR. But many drivers don't. As usual
with STR, YMMV.

> 2) Why did intel mandate 192kHz audio sampling in intel HDA? Are there any
> applications for such high sampling rates?

They didn't mandate 192 kHz. HDA leaves a lot of room for specific
implementations. 

Lennart

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Lennart Poettering                        Red Hat, Inc.
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