[Linphone-users] Re: MOS Reporting

[Joonbum Byun]

Using LRR (last receiver report) and DLRR (delay since last receive report) in  RTCP-XR (extended  report) may enable you to measure roundtrip propagation delay. Of course, two phones involved in a session must undersatand and support the receiver report.

I know Telchemy (http://www.telchemy.com/) owns some patent on MOS voice quality measurement, but not sure what is their scope of coverage.

Thanks,

Joon

>> 
>> Does Linphone have a feature of calculating MOS (Measn Openion Score) of a 
>> voice call? If yes, how the score is reported, RTCP, SNMP or ...? 
>
>As I know there is no satisfactory way  to calculate MOS on the fly.
>
>  * Originally proposed method (see ITU-T Rec. P.800) requires 
>absolutely unsuitable conditions (such as specially-equipped studios, etc)
>
>  * There is also PESQ (ITU-T Rec. P.862) which requires both reference 
>and degraded speech samples (as I suppose, this is also unsuitable for 
>the real-time quality estimation).
>
>  * Last chance is an E-model (ITU-T Rec. G.107) which originally was 
>proposed as quality estimation model for the circuit switching networks. 
>   Some of parameters of this model (such as one-way delay) cannot be 
>calculated without additional measurements.
>
>I'd like to hear if somebody knows another ways to calculate speech 
>quality or knows how to implement in real-time VoIP application some of 
>methods proposed below.
>
>Also I'm not sure but it seems that PESQ and E-model are patented.
>
>-- 
>WBR, Roman Imankulov
>address@hidden