continuous audio/video test request

Stuart Levy slevy at ncsa.uiuc.edu
Thu Apr 6 17:46:43 CDT 2000


> But when we went to one site transmitting 
> continuously for more than a couple of minutes, we started seeing 
> occasional dropouts.

It could be interesting to *time* the occurrence of the dropouts.
I've several times seen bursts of heavy loss occurring at regular
intervals -- like 70 seconds, or 5 seconds -- as though some router
were being periodically flooded with something (routing update traffic?).

A stable period, with common phase across multiple senders, would suggest
a network source as opposed to possibly being a rat or Linux-audio anomaly.

Vat could show this really nicely with its RTP graphs.  Too bad rat didn't
follow its example.


I first noticed this pattern when listening to the NASA Mars Pathfinder 
multicast transmissions, which were blatted out every ~70 seconds,
a pretty stable period, for days on end.  Got mad enough to do a study of it,
including writing an mtrace->perl->gnuplot tool.  In case it turns out
useful, the bundle is still at

   http://www.geom.umn.edu/~slevy/mtraces/

  Stuart Levy, slevy at ncsa.uiuc.edu



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