Wireshark-users: [Wireshark-users] rtp payload problem
From: miguel olivares varela <[email protected]>
Date: Mon, 23 Jun 2008 03:00:06 -0700

Hi everybody,

I'm working in a project about VOIP, so I have a question I found on the mailing list a discussion about how to calculate the jitter this is the link: http://www.wireshark.org/lists/wireshark-users/200702/msg00276.html   I got a capture file with RTP payload 96 I think is AMR codec. I want to calculate the jitter for this type of payload.  I found on the RFC 3267 that the sampling frequency used is 8000Hz and 16000Hz for AMR WB. I know the formula to calculate the jitter but in my file the timestamp is not constant like in G711 that is why the jitter values are so high. 

  

Does anybody know how can I calculate the jitter for this type of payload?

 

Thanks and best regards  

 

This is an example of my capture file

No.  Time        Source              Destination          Protocol   Info                                                           

      1 0.000000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=0, Time=2240             

      2 0.009000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=1, Time=2560              

      3 0.029000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=2, Time=2880             

      4 0.049000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=3, Time=3200            

      5 0.068000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=4, Time=3520            

      6 0.093000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=5, Time=3840             

      7 0.111000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=6, Time=4160            

      8 0.134000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=7, Time=4480             

      9 0.155000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=8, Time=4800            

     10 0.173000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=9, Time=5120            

     11 0.229000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=10, Time=6080          

     12 0.392000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=11, Time=8640          

     13 0.411000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=12, Time=8960          

     14 0.429000    10.184.16.7           10.184.11.14          RTP      PT=Unknown (96), SSRC=0x80DC9C12, Seq=13, Time=9280  

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