[asterisk-users] Meetme voice quality problems

[Tomasz Zieleniewski]

On Jan 30, 2008 5:48 PM, Matthew J. Roth <mroth at imminc.com> wrote:

> Tomasz Zieleniewski wrote:
> > I am using Debian OS kernel  2.6.22-3-amd64
> > and zaptel driver 1.4 with ztdummy module for meetme application.
> > I use meetme with SIP channels.
> >
> > I have such problem that when one connects to the conference voice is
> > "cut".
> > Each voice sequence is disturbed.
> >
> > Does any one have similar issue and could give me some advice??
> Tomasz,
>
> Have you run zttest on the system?  It verifies the accuracy of your
> timing source.  Digium recommends an accuracy of at least 99.98%.  If
> your accuracy is less than that it's probably the source of your problem.
>

ztttest results show value below 99,98:

asterisk at venom:~/src/zaptel-1.4$ ./zttest -v -c 5
Opened pseudo zap interface, measuring accuracy...

8192 zaptel samples in 4096.232 system clock sample intervals (50.003%)
8192 zaptel samples in 4064.232 system clock sample intervals (49.612%)
8192 zaptel samples in 4096.232 system clock sample intervals (50.003%)
8192 zaptel samples in 4096.240 system clock sample intervals (50.003%)
8192 zaptel samples in 4096.232 system clock sample intervals (50.003%)
8192 zaptel samples in 4096.232 system clock sample intervals (50.003%)
8192 zaptel samples in 4096.232 system clock sample intervals (50.003%)
8192 zaptel samples in 4064.232 system clock sample intervals (49.612%)
8192 zaptel samples in 4096.232 system clock sample intervals (50.003%)
8192 zaptel samples in 4096.232 system clock sample intervals (50.003%)
8192 zaptel samples in 4096.240 system clock sample intervals (50.003%)
--- Results after 11 passes ---
Best: 50.003 -- Worst: 49.612 -- Average: 49.931827, Difference: 49.931827


>
> Luckily, it's a problem with multiple solutions.  The following thread
> documents some kernel configuration changes that you can make to improve
> the quality of ztdummy as a timing source:
>
>  Recommendations for kernel config
> <http://lists.digium.com/pipermail/asterisk-users/2007-October/197778.html
> >
>

Do You know how can  I check and set kernel timer frequency?

>
>
> My preferred solution is to use an empty TDM400P as a timing source.  It
> will cost you a little bit of money, but it's an easy way to reliably
> solve your problem.  You'll find a few posts about it if you search the
> list, but this one has most of the information you'll need:
>
>  Empty Wildcard TDM400P as a MeetMe timer.
> <http://lists.digium.com/pipermail/asterisk-users/2007-March/182005.html>
>
> Regards,
>
> Matthew Roth
> InterMedia Marketing Solutions
> Software Engineer and Systems Developer
>
>
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