[asterisk-users] meetme conference using g729?

[Wai Wu]

But his preference of G729 is to save bandwidth.

-----Original Message-----
From: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Tim Panton
Sent: Wednesday, October 03, 2007 8:16 AM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [asterisk-users] meetme conference using g729?

Not exactly.
Here are the facts:
	meetme mixes in SLIN.
	Any data arriving in anything other than slin will get
transcoded twice,
		once on the way in and again on the way out.

Now some opinions:
	The more efficient the compression of the codec, the less well
it copes with
	decoding and re-encoding. Ulaw and Alaw are simple and not that
efficient,
	but you don't lose any more by re-encoding than you did by
decoding in the first place.
	Tighter codecs like 729 and GSM you will definitely hear the
difference.


Theory:
	If you have a conference where there is only _ever_ one speaker
	at a time, you could (in theory) optimize meetme to do without
mixing, and if all
	the participants were using the same codec, you could get away
with not re-encoding
	by sending out the appropriate incomming packet to all (other)
members.
	I'm guessing that isn't the case for you.

Advice:
	use Ulaw - it's a decent tradeoff for this sort of thing.

Tim.

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