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Steve Underwood wrote:
<blockquote cite="mid:4683A4F1.2010700@coppice.org" type="cite">
<pre wrap="">Martin Vít wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hello,
I'm testing 1.4.5 (no modifications) with E1 card and i've found problem.
I've this scenaro
FAX -> SIP - ATA -> asterisk -> E1 port A --loopback--> E1 port B -->
iaxmodem.
When jbenabled is off FAX is delivred OK. But when jbenable = on FAX are
failing in almost every line. I've compared WAV extracted from network
with WAV recorded (app monitor) before it gets to iaxmodem and there is
small differences. Network jitter is about 2ms (lab environment).
Where could jitterbuffer modifies frames? I've tried to disable plc in
plc.c but without success. Any idea?
</pre>
</blockquote>
<pre wrap=""><!---->This is correct behaviour. Most VoIP kit has the ability to disable
jitter buffering when a FAX is in progress.
</pre>
</blockquote>
<br>
I still dont understand, what is correct. I'll be more specific:<br>
<br>
FAX frames are delivering from SIP ATA to asterisk box, routed through
E1 and returned back to the same E1 and then to iaxmodem (it is silly
but just for test).<br>
<br>
If jbenable = yes in zapata.conf and in sip.conf, every rows in fax
are bad: <br>
<br>
<tt>Jun 28 14:48:10.25: [11153]: RECV/CQ: Bad 1D pixel count, row
763, got 2355, expected 1728</tt><br>
<br>
<br>
If jbenable = no in zapata.conf and sip.conf, everything are OK. <br>
<br>
I've checked debug file from jitterbuffer and it seems that all frames
are delivered ok<br>
<br>
<tt> JB_GET {now=136}: Delivered frame with ts=49147553 and
len=20<br>
JB_GET {now=156}: Delivered frame with ts=49147573 and
len=20<br>
JB_GET {now=176}: Delivered frame with ts=49147593 and
len=20<br>
<br>
</tt>I've tried adaptive and fixed jbiml, always the same<br>
<br>
So i've tried simulate fixed latency on my router (hold data for 200ms
from ATA to asterisk) and disable jb at all. FAX are OK. If jbenable =
yes - problem.<br>
<br>
There is something wrong with jbenable or am I missing something? <br>
<br>
Maybe there is somewhere activated PLC or some another filter? whenever
jbenable is turned on?<br>
<br>
Codec is alaw <br>
<br>
festr<br>
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