[Asterisk-Users] Re: Horrible MeetMe performance

[Dan Morin]

I read somewhere, probably the Wiki, that the core of MeetMe uses uLaw.
So when sound comes in, it is transcoded to uLaw first, then mixed with
all of the other audio at that moment, then sent out again.  At that
point, it is transcoded again to the original format.

So, if everything is in uLaw, you bypass 2 transcoding processes.  And
if you take into account both of those transcoding processes (with other
codecs), they add 10 or so milliseconds each time which results in ever
increasing delays. 

If you are using all uLaw connections, try changing one of them to iLBC
and try another conference.  I noticed 10 second delays after 5 minutes
of conference.

Let me know if you find anything else out about this.
Dan


-----Original Message-----
From: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Tony
Mountifield
Sent: Sunday, June 26, 2005 5:35 PM
To: asterisk-users at lists.digium.com
Subject: [Asterisk-Users] Re: Horrible MeetMe performance

In article
<9FEE3E56D424E243B7CA76B875B07326045F6B at sbserver.ABBCO.inner>,
Dan Morin <DMorin at ABBCOInc.com> wrote:
> Make sure that if you're using anything other than zaptel hardware, it
> is running uLaw as the codec.  Anything else will produce ever
> increasing delays.

Hey, now that's a snippet of information I hadn't seen before!

All my work with SIP and MeetMe is using aLaw, since I'm in the UK.

Do you know why it causes ever increasing delays? I would have thought
that a transcoding would just introduce a contstant (small) delay, not
an accumulating one. So if you're right, then it ought to be fixable,
once the mechanism is understood.

Cheers
Tony
-- 
Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org
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