Dear All,
Greetings,

I have configured Kamailio (4.0.3) with mediaproxy server, with this set-up audio/video calls are going good and hence NAT issue has solved.
I have used two soft clients: 1) IMSDroid 2) Bria.
But i have a query about media-proxy statistics i.e in the syslog, the info about media-proxy activity is shown as below:

Case 1: when Call between two IMSDroid clients.

caller_codec : 'Unknown(73)'

callee_codec : 'Unknown(73)'

callee_ua : 'unknown agent'.

Case 2 : When call between two Bria clients.

'callee_ua': 'unknown agent'.

(Calls using Bria clients media-proxy's syslog shows Audio codec names, but using IMSdroid clients it is showing 'Unknown' for Audio codec names ).

Find the attachment below for the full syslog about the mentioned unknown behaviour. And also find my kamailio.cfg file.

And also logging in the syslog as shown like RTP: Unknown , RTCP: Unknown.

In this context, there is a jitter in audio calls and pixelled video sometimes, So is there any wrong with the above mentioned "unknown' factor in this problem of jitter/pixelled audio/video calls ?
(AFAIK these payload type 73 (i.e 72-76) is reserved for RTCP conflict avoidance. right? ) 

What could be the problem for this 'Unknown' issue?
How can i solve this issue ? Anything can be done in kamailio script?
And how these RTCP payload types (72-76) plays a role in audio/video calls?

Any suggestions will greatly help. please help me in clarifying these issues.

Thanks in advance.

Regards,
Nandini