Re: [GnomeMeeting-list] How to fix sound choppy on CPU load?

["Mihai T. Lazarescu" <mihai email it>]

Thank you, Craig, for your reply.

On Thu, 6 Nov 2003, Craig Southeren wrote:

You are right, of course, about the buffering/latency trade-offs
that differentiate GM vs. other streaming/players, especially
when buffering takes place on the audio driver.

> Appliciations such as Xine are even less useful for comparison. Not only
> do they do extensive buffering, but they have no dependence on network
> traffic (unless you are using NFS mounts :).

Recently there is a http://... input for xine... :-)

> GM does not require much overall CPU power (especially for high speed
> processors), but maintaining real-time performance does require regular
> chunks of CPU time for every incoming and outgoing packet. If the CPU is
> being heavily used, GM will not be able to keep up with the incoming
> packets in real-time, nor will it be to keep sending packets fast enough.
> This will result in exactly what you are getting - choppy audio and
> video at both ends.

I reopen my original question: would you agree that this
effect should be alleviated (if not solved right away) by
increasing the priority of the GM process?  My experiments
show no noticeable difference while playing with GM process
priorities up to -20.

> a) ...the NPTL patches should help...

I used the workaround that helped in other situations,
setting the environment variable LD_ASSUME_KERNEL=2.4.1,
but no effect again.

> b) Increase the minimum jitter buffer size.

No effect in my case.

> c) Increase the number of frames per packet in outgoing packets.

How can I do this?

> d) Don't do compiles while talking :)

Avoiding that won't be a problem, :-) although I suspect niced
compilations and prioritized GM should mitigate/solve it.

The problem is that I get audio silence for every *small*
CPU intensive event, even opening/closing an rxvt produces
a few fractions of a second of silence!  Worse when Mozilla
renders a page (just text, no java or flash).  Not to mention
spamassassin processing incoming messages, or xsetbg (niced
to lowest priority) displaying a new background image, etc.

I suspect that the GM users are not supposed to switch to
single user to have proper audio... :-) Actually no, since it
seems that no other users besides me experience this erratic
behavior. :-(

Thanks for your suggestions anyway.

Mihai