Wireshark · Wireshark-users: Re: [Wireshark-users] A question about calculating "Mean Jitter" KPI for RTP flow

[Jaap Keuter <jaap.keuter@xxxxxxxxx>]

HI,

Hopefully someone finds some time to look into it. So rest assured it’s not forgotten. 

Thanks,

Jaap

On 22 Sep 2021, at 10:33, Nan Xiao <xiaonan830818@xxxxxxxxx> wrote:

Hi Community,

Greetings from me! Very sorry for interrupting again!

I find the calculation of "Mean Jitter" KPI for RTP flow is like this (https://gitlab.com/wireshark/wireshark/-/blob/master/ui/tap-rtp-analysis.c#L497):

statinfo->mean_jitter = (statinfo->mean_jitter*(statinfo->total_nr-1) + current_diff) / statinfo->total_nr;

But in my humble opinion, maybe we should use current_jitter instead of current_diff? Like following one:

statinfo->mean_jitter = (statinfo->mean_jitter*(statinfo->total_nr-1) + current_jitter) / statinfo->total_nr;

Actually, I submitted an issue in gitlab before (https://gitlab.com/wireshark/wireshark/-/issues/17600), but unfortunately, it seems no one noticed it. So very sorry for reposting here, and hope someone can help to clarify it.

Thanks very much!

Best Regards
Nan Xiao