Wireshark · Wireshark-dev: [Wireshark-dev] Question regarding the information provided by Wireshark in the "RTP Stream Analysis

["Andreina Toro" <andreina.toro@xxxxxxxxx>]

Hi everyone, I have a question regarding the calculation of interarrival jitter and the information provided by Wireshark in the "RTP Stream Analysis Wndow" for each call.

I can see that Wireshark gives me in the 4th Row of the RTP Stream Analysis Wndow the Jitter for each packet of each call.

 

In the other hand I´ve read that:

 

"If Si is the RTP timestamp from packet i, and Ri is the time of arrival in RTP timestamp units for packet i, then for two packets i and j, D may be expressed as 

                                           D(i,j)=(Rj-Ri)-(Sj-Si)=(Rj-Sj)-(Ri-Si)

The interarrival jitter is calculated continuously as each data packet i is received from source SSRC_n, using this difference D for that packet and the previous packet i-1 in order of arrival (not necessarily in sequence), according to the formula                                 J=J+(|D(i-1,i)|-J)/16

Whenever a reception report is issued, the current value of J is sampled."

 

What I don´t have clear is what this Jitter in the 4th Row represents in the interarrival jitter calculation?

 

Can I calculate the jitter J, defined to be the mean deviation, with that data? I mean, can I use the values of the jitters of each packet given in that RTP Stream Analysis in every call and calculate the difference D??

                       

Thanks, and sorry for any inconvinience

Best Regards,

Andreina