Subject: [MMUSIC] draft-li-mmusic-fec-grouping-01 as a WG item?

From: Magnus Westerlund <[email-masked]>
Date: Thu, 15 Sep 2005 13:54:02 +0200

Hi,

A new version of this draft become available yesterday. I have reviewed 
the few pages and I think this is a good idea. I would like to request 
that MMUSIC adopts it as an WG item to help AVT complete the work on 
ULP. However I would like to ensure that this solution is not locked to 
ULP and that other future FEC mechanism may adopt this if suitable.

I do also have a few comments on the draft where I think it can be improved.
1. Section 3, second last paragraph:
   "When FEC data are multiplexed with the original payload stream, the
    association relationship is indicated as specified in RTP Payload for
    Redundant Audio Data (RFC 2198) [4]. As an example, such relationship
    can be indicated as in the generic RFC payload format for FEC [5]."

I would propose that this is changed to be more generic and less ULP 
specific. `

    When FEC data are multiplexed with the original payload stream, this 
is explicitly indicated as defined by the FEC mechanism. An example of 
this is when generic RFC payload format for FEC [5] use the RTP Payload 
for Redundant Audio Data (RFC 2198) [4].

2. Section 3, last paragraph. The first sentence seems to indicate that 
there are many ways of doing indications for separate streams, while 
this is so far only the second. Where the first one documented in RFC 
2733 was a bad way of doing it. I would rephrase this into something 
more target to say that this is what this draft documents.

3. section 4.1:
"Each "a=group" line are used to indicate the association relationship
    between the FEC streams and the payload stream."

This sentence is missing the clarification that it concerns a a=group 
line using the "FEC" semantics. I would suggest

Each "a=group" line with the "FEC" semantics are used to indicate the 
association relationship between the FEC streams and the payload stream.

4. Section 4.1, second paragraph. "one or more than one" I would propose 
to shorten to "one or more" as it is much easier to read.

Cheers

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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From: Colin Perkins <[email-masked]>
Date: Fri, 16 Sep 2005 11:51:45 +0100

On 15 Sep 2005, at 12:54, Magnus Westerlund wrote:
> A new version of this draft become available yesterday. I have  
> reviewed the few pages and I think this is a good idea. I would  
> like to request that MMUSIC adopts it as an WG item to help AVT  
> complete the work on ULP

Are there any comments or objections on this proposal from the group?  
Please respond by 23rd September so the chairs can gauge opinion.

Colin

---

From: Magnus Westerlund <[email-masked]>
Date: Fri, 23 Sep 2005 16:10:24 +0200

Hi,

One more comment on the technical side of the draft. It is missing an 
offer/answer usage section which is something that is needed. It can 
most likley simple extend on the one in RFC 3388.

Cheers

Magnus

-- 

Magnus Westerlund