Re: [xrblock] Call for adopting xr-quality-monitoring-06 as WG item

Shida,

I don't think this draft is ready to adopt:

- The single-stream metric mixes audio and video MOS into a single metric block, with a grab-bag of MOS type and calculation algorithm parameters. It seems that little thought has gone into designing the XR block format to prohibit invalid combinations (e.g., MT = MOS-V with CALg = G.107), and there is no guidance on which algorithm is appropriate for which MOS type. The format seems to follow the RFC 3611 model, throwing together a set of unrelated parameters, rather than the approach documents in the monarch draft.

- The multi-layer segment is ill-specified: does it support audio only, video only, or both depending on the Media Type bit? Which calculation algorithm makes sense here, since there is no guidance given, and it's possible to specify any algorithm? What is the SSID field? How it is used? It's not sufficient to simply say that a "NAL unit type is one example", the draft needs to give normative rules for the use of this field.

- The media type, MOS type, and calculation algorithm for the multi-channel segment are ill-specified in similar ways to the multi-layer segment. Also, it's not clear that the channel mapping in RFC 3550 Section 4.1 is the only one in use.

- In general, it's not clear to me that including multiple different types of MOS report (single-stream, multi-layer, and multi-channel) in a single draft fits with the monitoring architecture, which encourages small, single-use, XR block definitions. I would suggest that the three different MOS report types would be better defined as three drafts: there is little in common between them.

- The draft provides no meaningful guidelines for registration of new MOS algorithms, and has an inadequate IANA registry.

Colin

On 19 Dec 2011, at 11:55, Shida Schubert wrote:
> This is a call to see whether people are happy 
> with the latest xr-quality-monitoring-06 draft for addressing 
> the milestone "QoE Metrics Reporting".
> 
> http://tools.ietf.org/html/draft-wu-xrblock-rtcp-xr-quality-monitoring-06
> 
> xr-que-00 which used to be an AVT draft also addresses 
> the same milestone. 
> 
> http://tools.ietf.org/id/draft-clark-xrblock-rtcp-xr-qoe-00.txt
> 
> The xr-quality-monitoring-06 claims to merge the two 
> into one. 
> 
> Please response to express your option for the followings. 
> 
> 1. Adopt the draft-wu-xrblock-rtcp-xr-quality-monitoring-06 as a WG item. 
> 
> 2. Not ready to adopt.
>   * Would be very helpful if you provide your reasonings.
> 
> Regards
>  Shida (as chair)
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> xrblock@ietf.org
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-- 
Colin Perkins
http://csperkins.org/