Subject: Re: [AVT] working group last call: draft-ietf-avt-rfc2429-bis-06.txt

From: Magnus Westerlund <[email-masked]>
Date: Tue, 18 Oct 2005 18:08:37 +0200

Hi,

I will hereby declare this last call as ended. However I do have some 
comments:

1. Section 1: Says that this draft updates RFC 2429. Shouldn't that be 
Obsoletes? In addition i think it updates RFC 3555 as it moves the media 
type registration of video/h263-1998 to this document instead of RFC 3555.

2. Section 3.1: Shouldn't the usage of sequence number be mentioned 
here? As I understand it one uses the RTP headers sequence number to 
recover the order of the parts of a compressed video stream for a single 
frame if split between multiple RTP payloads.

3. Section 5.1: RR definition: I think "shall" in this sentence should 
be SHALL as it is a normative statement.

4. Section 8.1.1: The media type parameters MUST have value according to 
RFC 2045 ABNF. I would recommend that you use a "true" "false" values or 
simply 0 and 1 to indicate usage. Also a default behavior when not 
present for the Annexes should be defined.

5. Section 8.1.1:

Encoding consideration:
This should point at draft-freed-media-type-reg-03 classification as 
being "framed". Suggestion:
"This media type is framed, see section 4.8 in [freed]."

Restriction on usage:
This should read:
	This media type depends on RTP framing, and hence is only
         defined for transfer via RTP [RFC3550]. Transport within other
         framing protocols is are defined at this time.

6. Comments 4 and 5 does also apply to 8.1.2

7. Section 9:

Are there any minor backwards compatibility issues with RFC 2429 
implementations? If not I would suggest to remove "major".

8. Section 10. Please remove the following sentence:
"Because the data compression used with
    this payload format is applied end-to-end, encryption may be
    performed after compression so there is no conflict between the two
    operations."

The reason is that it is necessary to perform compression before 
encryption. As this payload format also only support encryption of a 
complete payload this should either be specified or left out. I think it 
is simpler and not an issue to remove this potentially confusing sentence.

9. Section 10: Third paragraph: This text is not relevant to an RTP 
payload format it is something that is common. In addition the text is 
misleading: RFC 2032 is called future version. I recommend removal of 
the complete paragraph.

10. Section 12: Please clean up this section to only include relevant 
changes from RFC 2429. The inter version changes are irrelevant when 
published.

11. Classification of normative references: A normative reference is 
something that is required to be read or followed to implement this 
correctly. Looking at the text where [Vredun] is used this is an 
informative reference. However not having read it I can be in error.

Based on my comments I don't think the draft is ready for publication 
without some updates. We also need to send it for media types review 
which we chairs have forgotten. Therefore when the issues has been 
resolved and an update is available we will have a new WGLC in 
conjunction with an media type review. This second WGLC will be on the 
modified parts and only serious errors not raised in this WGLC will be 
considered.

Cheers

Magnus

Colin Perkins wrote:
> This is to announce a working group last call on the revised RTP  
> Payload Format for the 1998 Version of ITU-T Recommendation H.263  Video 
> (H.263+):
> 
> http://www.ietf.org/internet-drafts/draft-ietf-avt-rfc2429-bis-06.txt
> 
> Please send any final comments on this draft to the list by 14  October 
> 2005. If no substantive issues are raised by that time, we  intend to 
> request the IESG publish this as a proposed standard RFC.
> 
> Colin
> 
> _______________________________________________
> Audio/Video Transport Working Group
> [email-masked]
> https://www1.ietf.org/mailman/listinfo/avt
> 

-- 

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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