On 01/05/2012 12:55 PM, [email protected] wrote:
David Henningsson wrote:
in Oneiric (and PulseAudio 1.0)
Do you mean "in PA 1.0, which is the one included in Oneiric"?
Yes, PulseAudio 1.0, and an alsa-plugins package that makes use of the
new information, are both included in Oneiric. Sorry for the ambiguity.
Or do you really mean Ubuntu-specific patches?
Or simply a backport of 1.0 into Oneiric?
[...caused by the asynchronous nature of PulseAudio...]
Very interesting read, thank you.
I'll summarize your explanation saying that XRUN mode is not reliable in PA<
1.0.
A few month ago, we had ALSA run in what I call streaming or nonstop mode, i.e.
with stop_threshold = boundary and some values of silence_size&threshold.
Would you recommend using the nonstop mode with PA?
I feel I know too little about wine to give a recommendation, but I'd
think that wine is a big enough project to justify a pulseaudio driver,
one that talks to PulseAudio directly without passing through the
ALSA-Pulse plugin. If that is not an option, I'd suggest relying on the
XRUN message for PulseAudio 1.0 and not relying on XRUN for PulseAudio <
1.0. If there still are XRUN related bugs in PulseAudio 1.0, we should
try to sort them out.
We reverted that for several reasons as it didn't work well with ALSA in
general (I can't
remember exactly, but to detect underruns it needs reliable avail_update>
buffer_size,
also I remember issues with dmix when trying snd_pcm_forward to catch up after
an underrun, as well as dmix' behaviour of playing silence while catching up,
which
explains why people hear silence despite megabytes fed to ALSA -- it was simply
considered too late, e.g. snd_pcm_delay< 0).
Yet I could imagine changing Wine to behave as follows:
if pulse is detected as the ALSA plugin backend, use nonstop mode and rely on
avail_update>buffer_size to detect underruns; otherwise rely on XRUN.
Underrun detection and recovery is an essential requirement for producing sound
reliably.
For some applications, yes.
--
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic
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