asterisk users - Oct 2005 - echo codec related?

Hi, I'm having a problem with my IAX2 VOIP service provider in that a
large number of calls now exhibit varying echo at least 1 in 3 calls
outgoing and almost 50/50 incoming.

 

They have just replied saying it is codec related and for me to change
codecs.

 

Is this for real? Can echo be codec induced or are they spinning me a
line?

 

 

Cheers,

Dean

 

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One trusts that the vendor or service provider knows their system
best... however, to answer your question; yes, it's plausible that the
choice of codecs _could_ interfere with proper echo cancellation.
Scenarios that spring to mind include an improperly implemented codec
that is causing the signal levels received at the ITSP to be way too
high thereby offending their echo canceller; perhaps a codec that is so
lossy that it doesn't implement a broad enough spectrum signal for the
echo cancellation algorithm in use and so on. However, all of these are
entirely supposition without knowing intimate details of both your and
the ITSPs systems, which is unlikely to be disclosed.
 
Out of interest though; what codec were you using successfully and for
how long, and what do they recommend you use now?
 
Kris Boutilier
Information Services Coordinator
Sunshine Coast Regional District



________________________________

	From: asterisk-users-bounces@lists.digium.com
[mailto:asterisk-users-bounces@lists.digium.com] On Behalf Of Dean
Collins
	Sent: Monday, October 31, 2005 5:15 PM
	To: Asterisk Users Mailing List - Non-Commercial Discussion
	Subject: [Asterisk-Users] echo codec related?
	
	

	Hi, I'm having a problem with my IAX2 VOIP service provider in
that a large number of calls now exhibit varying echo at least 1 in 3
calls outgoing and almost 50/50 incoming.

	 

	They have just replied saying it is codec related and for me to
change codecs.

	 

	Is this for real? Can echo be codec induced or are they spinning
me a line?

	 

	 

	Cheers,

	Dean

	 

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On Monday 31 October 2005 20:14, Dean Collins wrote:
> Is this for real? Can echo be codec induced or are they spinning me a
> line?
Kris has given the most reasonable answer but I'd like to throw in the 
possibility that poor codec implementation may cause additional delay which 
is pushing the echo "tail" beyond that of what the echo
canceller's able to
detect as echo.  This would point to an overutilized CPU...

*shrug*  Just a thought.  

-A.