[AVT] RE: Suggestion for how to handle derived/computedmetricindraft-avt-rtcpxr-*

["Ingemar Johansson S (LU/EAB)" <ingemar.s.johansson at ericsson.com>]

Hi

Coming from the area to speech and audio compression I can only second the opinion that you really must specify what algrithm you are using. Lots of work has been done to try to pair subjective quality measurements against objective measurements and the results are not always straightforward. One typical problem is impact of longer packet loss where the models and what people actually perceive differs.

Another big problem is that I cannot see how you account for jitterbuffer adaptation in this case, especially if you use adaptive jitterbuffering. My fear is that you only get to a point where you compare apples and oranges. But I wont argue more about the applications and the reliability. 

Besides all this I find it a bit too static to specify binary RTCP report blocks for every kind of computed metric that one can come up with. A better solution would be some kind of an XML structure that allows for more dynamics. I know it is probably/maybe not doable for bandwidth reasons but extensibility would be alot easier then. 

Why use RTCP at all for this ?, I sort of get the feeling that these are reports that are sent by the clients when he hangs up and the clients gather up all the statistics.

Regards
Ingemar
*******************************************
Ingemar Johansson
Senior Research Engineer
EAB/TVP - Multimedia Technologies 
  Ericsson Research Ericsson AB 
  Box 920 S-971 28 Luleå, Sweden
Tel: +46 (0)8 4043042
ECN: 850-43042
Mobile: +46 (0)730 783289
MSN: ingemarjohansson1965 at hotmail.com
*******************************************
 

_______________________________________________
Audio/Video Transport Working Group
avt at ietf.org
https://www1.ietf.org/mailman/listinfo/avt