[Asterisk-Users] Clicks in audio with TE100P PRI

[Alejandro G]

In zapata.conf


; Configure jitter buffers in zapata (each one is 20ms, default is 4)
;
jitterbuffers=16

Alejandro Ghergherian


-----Mensaje original-----
De: Rod Bacon [mailto:rod.bacon at empoweredcomms.com.au]
Enviado el: Domingo, 25 de Septiembre de 2005 08:32 p.m.
Para: Asterisk Users Mailing List - Non-Commercial Discussion
CC: ag2005 at fibertel.com.ar
Asunto: Re: [Asterisk-Users] Clicks in audio with TE100P PRI


Which file does the jitterbuffer setting go in, zaptel or zapata.conf?

I can't find it documented anywhere. What version of zaptel drivers include
a
jitterbuffer?



==========================================
Rod Bacon
Empowered Communications
Ground Floor, 102 York St. South Melbourne
Victoria, Australia. 3205
Phone: +613 99401600    Fax: +613 99401650
FWD: 512237                   ICQ: 5662270
==========================================


Alejandro G wrote:
>
> I tested all again. No matter if span=1,1,0  or span=1,0,0 if I configure
> jitterbufer=4 I have glitches that I'm almost sure that are "holes" in
> audio.
>
> If I raise jitterbufer=16 the problem disappear (or becames impercetible).
> Anyway I am interested in understand what is happening.
>
>
>>Your issue is very likely the size of the zaptel jitterbuffers setting. If
>
> the zaptel driver is not
>
>>immediately available to accept a frame of data it places it in an
>
> internal queue of pending writes.
>
>>If that queue is full then the write is refused by the zaptel layer and
>
> then silently discarded by
>
>>chan_zap causing a gap in the audio once it is played out of the zaptel
>
> card. If you crank up the
>
>>debug level you will probably see 'Write returned -1...' (aka. EAGAIN)
>
> debugs that mostly correlate to
>
>>the pops and clicks. Note that the zaptel driver legitimatly (if perhaps
>
> not appropriately) also
>
>>refuses data when the channel is muted, such as during DTMF generation and
>
> at other times, so not
>
>>_all_ EAGAIN debugs are a sign of problems.
>
>
>
> This makes perfect sense but again some issues of the problem do not
match.
> I set debug at level 9 and  there is no message of errors. Another thing I
> do not understand is why the same configuration:
>
> PAP2 <-> LAN <-> Asterisk <-> TE100P  works perfect, and instead of LAN
> using internet generates the problem. Shouldn't it be the same for both
> configs?
>
> The only difference I see is that the rtp packets came from another
Ethernet
> card, but if I call to terminate calls with another carrier using that eth
> works fine.
>
> What is clear is that jitterbuffer=16 corrects the problem.
>
> One more thing: no matter what codec I use, G729 or G711 the sound clicks
> are almost the same.
>
> Is anyway I could debug at RTP level in asterisk to see what is happening
> and check if there is packet loose?
>
> Thanks
>
> Alejandro
>
>
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