Its my mistake .. i am not taking care of msec ..
thanks.
From: cool_capricorn80@xxxxxxxxxxx
To: wireshark-users@xxxxxxxxxxxxx
Date: Sat, 15 May 2010 11:58:45 +0000
Subject: [Wireshark-users] Wrong calculation of jitter by wireshark
Hi!
I have captured the RTP packets on receiving side and check the values of jitter and than i calculated the values manually and it looks like wire shark is not calculating the values in correct way or may be I am doing some thing wrong. I am pasting all me calculation so that you people can verify it.
Frame 18
Time of Arrival: 29.490533000
Timestamp: 365000
Frame 20
Time of Arrival : 29.501315000
Timestamp: 365160
D(i,j) = (Rj - Ri) - (Sj - Si) = (Rj - Sj) - (Ri - Si)
J(i) = J(i-1) + (|D(i-1,i)| - J(i-1))/16
D = (29. 501315000- 29. 490533000) – (365160*0.000125 – 365000*0.000125)
= -0.009218
J = 0 + (|-0.009218| - 0)/16
= 0.576 msec
Frame 22
Time of Arrival: 29.520124000
TimeStamp: 365320
(29.520124000 - 29.501315000) – (365320*0.000125 – 365160*0.000125)
=-0.001191
J= 0.576+(|-0.001191|-.576)/16
J= 0.54 ,
Wireshark calculation for frame 22 = 0.61
Frame 24
Time of Arrival: 29.539717000
Time Stamp: 365480
D=(29.539717000 - 29.520124000) – (365480*.000125-365320*.000125)
D= -0.000407
J=0.54+(|-.000407|-.0.54)/16
J=0.50
Wireshark Calculation for frame 24 = 0.60
Really thanks for your time.
Regards,
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