[AG-TECH] Audio problems

Osland, CD (Chris) C.D.Osland at rl.ac.uk
Mon Jan 27 05:17:49 CST 2003


My initial thought is - not much!  Packet loss doesn't seem, from
what I've seen, normally to be caused by a site producing too many
packets, but by network problems.  Therefore at any given time
the AG node in question might, say, lose 5% of its packets.  Whether
that is 5% of a low rate, or 5% of a high rate, the result will still be
that for 5% of the time the node doesn't have sound.  That's enough
to cause people to have to ask for things to be said again, and that
has a severe impact on the quality of the meeting.
 
I guess I am assuming that the AG traffic through your local
network, while it may be the largest single 'user', is well below
the capacity of the weakest link - that's the situation we have
here.  If the AG traffic was a substantial fraction of the maximum
bandwidth of the weakest link, then other rules might apply, but I
can't think of anything you can do unilaterally that will improve
things.
 
For meetings of up to about 5 sites I always suggest that we ALL
run without silence suppression (in RAT) or gating.  For larger meetings,
silence suppression or gating can be useful - meetings with 12
nodes might have 30 or 40 open mics and that's a lot of
background sound.  If everyone used silence suppression, I guess
that would reduce total bitrates.  Whether that would improve
things would depend on how the total audio bitrate compared
with the total video bitrate, and how those two together
compared with the maximum bandwidth through the weakest
link.
 
Cheers
 
Chris
 

____________________________________________________________________ 
Chris Osland                                               Office tel: +44
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Digital Media and Access Grid                          Medialab tel: +44 (0)
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-----Original Message-----
From: Ramon Newton [mailto:newton3 at llnl.gov]
Sent: 24 January 2003 17:19
To: ag-tech at mcs.anl.gov
Subject: [AG-TECH] Audio problems


Hi,
 
What are some ways (if any) to help improve your audio during a meeting if
you start getting packet loss?
 
Any ideas.
 
Thanks,
 
Ramon Newton
LLNL 

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