Wireshark-dev: Re: [Wireshark-dev] Voice (RTP stream) quality - mos, delay, bandwidth, ...
From: "Lars Ruoff" <[email protected]>
Date: Tue, 6 Nov 2007 11:46:26 +0100
 

> -----Original Message-----
> [mailto:[email protected]] On Behalf Of Guy Harris
> 
> daniel zhang wrote:
> 
> > 1. MOS
> > Voice quality was traditionally reported as a Mean Opinion 
> Score (MOS) 
> > on a scale from 1-5 where 1 is the lowest and 5 the highest.
> > I am not an expert on this but I think probably we could 
> add the MOS 
> > into Ethereal.
> 
> At least according to the Wikipedia article on the Mean Opinion Score:
> 
> 	http://en.wikipedia.org/wiki/Mean_Opinion_Score
> 
> the score comes from people listening to particular phrases 
> and giving their 1-to-5 rating of the quality of the sound, 
> not from a calculation you could perform on a raw digital 
> signal.
> [...]

That's true, but there have been many attempts to model MOS from raw data
directly.
The most prominent being the ITU G.107 "E-Model".
But still, the model includes parameters like the audio characteristics of
the end devices, jitter buffer implementations and so on, so MOS cannot be
calculated from a network trace without making specific  assumptions on the
end devices and audio path.

Best regards,
Lars Ruoff