[Asterisk-Users] Re: Lag in meetme

[Tony Mountifield]

In article <79cf633050408155745b8483b at mail.gmail.com>,
BJ Weschke <bweschke at gmail.com> wrote:
>  What version of * are you running? There was a bug that was posted a
> few weeks back where when not using the "q" option it was possible for
> legs of the conference to get further separated from each other
> (sometimes up to 3-5 secs after 60 mins of conferencing). The bug is
> in mantis and there is a patch that seems to keep that down to no more
> than 1/2 to 3/4 second after several hours of conferencing, but I'm
> not certain that this patch made it back into the CVS-HEAD branch.

It didn't (I was the proponent of the patch). I disagreed with Mark's
alternative solution, and still do, so it's sort of stalled for now.

The patch plays tones and announcements destined for the whole conf
using a separate thread. Playing and waiting for them inline causes
the channel's own queue not to be serviced, developing a backlog.
This applies mainly to enter/leave sounds and '"Fred" has joined'
announcements.

I believe there are other lag issues in non-Zap meetme that are not
addressed by my patch, but I haven't had time to investigate them
thoroughly yet. If I set up a meetme between two SIP phones with the
'q' flag set, I start off with negligible delay. If I just leave the
conference running, that delay builds, up to the 1/2 to 3/4 of a second
as reported above, but then sometimes disappears before building again.

I haven't yet determined whether the lag is on the SIP->conf leg or
the conf->SIP leg, or both. My suspicion is that it is drift due to
clock differences between the ZAP timer and the SIP device, but am
not sure how to determine when a frame should be dropped or duplicated.

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