[Freeswitch-users] Doubts over G729 passthru for 50ms ptimes

[Ben]

Hi Brian,

I looked at the timestamps for both RTP streams that are being sent by each
client, it appears that the timestamp increments by a value of 400 for each
packet, for both streams.  I can also see this in FS for each stream - 

2012-12-03 15:51:03.374955 [DEBUG] sofia_glue.c:5094 Audio Codec Compare
[G729:18:8000:50:8000]/[G729:18:8000:50:8000]
2012-12-03 15:51:03.374955 [DEBUG] sofia_glue.c:3077 Set Codec
sofia/internal/1002 at 192.168.17.154 G729/8000 50 ms 400 samples 8000 bits

Looking at the Freeswitch log, I'm guessing that the timestamps set by the
client correlate to the sample rate set by Freeswitch?  Or am I not on the
right track with what you were suggesting?

I've also noticed that when using 50ms ptimes, one of the RTP streams from a
client is not very 'steady'.  One stream seems acceptable, with only one or
two packets straying to 60ms, and jitter hovers around 2-3ms.  However the
other stream really struggles, the delta(ms) values in wireshark are all
over the place.  This is the summary of a 20 second RTP stream in wireshark
-

Max delta = 120.95 ms at packet no. 1250 
Max jitter = 22.00 ms. Mean jitter = 18.12 ms.
Max skew = 65.24 ms.

This seems odd since the test I did was all internal on the same LAN.  I'll
try and track down the cause tomorrow by switching around some kit so that
it cuts out any potential problems.  

Are there tolerance levels in Freeswitch for RTP streams that are affected
during transit?  If so, how does Freeswitch react when one of these
tolerance levels is exceeded?  My FS server seems to just hang during call
setup, and no RTP stream is sent out the server to the clients.

Thanks for the help, I'll let you know how I get on tomorrow with some
further tests.

Regards,

Ben	


-----Original Message-----
From: freeswitch-users-bounces at lists.freeswitch.org
[mailto:freeswitch-users-bounces at lists.freeswitch.org] On Behalf Of Brian
West
Sent: 04 December 2012 15:11
To: FreeSWITCH Users Help
Subject: Re: [Freeswitch-users] Doubts over G729 passthru for 50ms ptimes

PCAP's will show you.... I suspect something is telling a lie about the
timestamps.  Very common.
--
Brian West
brian at freeswitch.org
FreeSWITCH Solutions, LLC
PO BOX PO BOX 2531
Brookfield, WI 53008-2531
Twitter: @FreeSWITCH_Wire
T: +1.918.420.9266  |  F: +1.918.420.9267  |  M: +1.918.424.WEST
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ISN: 410*543





On Dec 3, 2012, at 9:31 AM, Ben <ben122uk at gmail.com> wrote:

> I tried setting the {passthru_ptime_mismatch=true} variable in the
dialplan, but no joy unfortunately.  I'm also fairly sure that the codecs
are matched on both call legs, so shouldn't be having that sort of issue.
>  
> I'm going to gather up some evidence and console logs/traces etc so that I
can put something together for a bug report on Jira.  Is there anything else
that someone can suggest I try before it goes on Jira?  Is anyone able to
re-produce the same problem?  Admittedly, I'm not on the latest GIT, but I'm
on a recent (last couple of months) stable release.
>  
> Thanks in advance for any assistance!
>  
> Regards,
>  
> Ben
>  


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