[cisco-voip] Transcoder garbles audio

[Kris Seraphine]

I have a customer who's been complaining about audio becoming garbled
and unintelligible for g729 participants in conference calls.  I finally
had some time to replicate the scenario in my lab and I can reproduce it
at will but for the life of me I can't figure out a solution.
 
On any call that goes through a transcoder, after approx. 30 minutes,
the g729 audio becomes garbled and stays this way for 8 minutes; at
which point it clears up.  This is 100 % reproduceable and always
happens with the same timing (plus/minus a minute or two).  During the
time the g729 end hears the garbled audio, the other participants can
hear the g729 user clearly.
 
It happens on conference calls and direct two party calls that go
through a transcoder; so the problem has to be either the transcoder or
phone load I'd guess.  The customer is running CCM 4.02a.  I'm using
4.02asr1.  I'm using a 2801 in the lab so my ios options are limited but
the customer is using a 1760 and I've tried 12.3(8)T and 12.3(11)T and
the problem exists in both.  
 
It's hard to beleive this isn't a known issue since its so easily
reproducible and seems to exist across platforms and ios releases but I
can't find anything in the bug tool.  The TAC seems to be stumped as
well.  I've had a case open for about a month now.  
 
Just wondering if anyone has any suggestions or maybe has seen this
issue themselves.
 

Kris Seraphine
  

 
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