Wrong calculation of jitter by wireshark

[capricorn 80 <cool_capricorn80 () hotmail com>]

 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,




                                          
Hotmail: Free, trusted and rich email service. Get it now.                                        
_________________________________________________________________
Your E-mail and More On-the-Go. Get Windows Live Hotmail Free.
https://signup.live.com/signup.aspx?id=60969

___________________________________________________________________________
Sent via:    Wireshark-users mailing list <wireshark-users () wireshark org>
Archives:    http://www.wireshark.org/lists/wireshark-users
Unsubscribe: https://wireshark.org/mailman/options/wireshark-users
             mailto:wireshark-users-request () wireshark org?subject=unsubscribe