Subject: Re: [AVT] I-D ACTION:draft-ietf-avt-rtp-vc1-01.txt

From: Colin Perkins <[email-masked]>
Date: Sun, 6 Nov 2005 19:40:01 -0800

Anders,

On 26 Oct 2005, at 14:07, Anders Klemets wrote:
> I would appreciate if members on the list could review the -01 version
> of the RTP payload format for VC-1.  (draft-ietf-avt-rtp-vc1-01.txt)

Some comments on the draft:

Section 1 is very terse, and some more introduction would be useful  
(section 3 is helpful, but still the introduction could still be  
expanded).

There are several cases where the draft says "When the VC-1 Advanced  
Profile is used..." and then defines a set of rules. Each of these  
needs to be followed by "When the Simple or Main profiles are  
used...", with an equivalent set of rules for those cases.

Section 5.2: need to specify network byte order for the fields

Section 6.1: the "width" and "height" parameters are presumably  
"integers greater than zero" rather than "decimal numbers"?

Section 6.1: what are the units for the "bitrate" parameter?

Section 6.1: the "bitrate" parameter is defined to exclude RTP  
overhead. This is okay, but what exactly does the RTP overhead  
comprise? (i.e. are the IP or UDP headers included? The fixed RTP  
header? The RTP payload header?)

Section 6.1: note that the "buffer" parameter relates to the codec  
only, and excludes network jitter buffering?

Section 6.2: the "level" parameter is optional, but doesn't have a  
default value. What to do if it is missing?

Section 6.2; the "Framerate" parameter doesn't have a default, and  
can be calculated from the level of the encoding profile. Okay, but  
what if the level is not specified?

Does IANA need define any parameter registries? Can any of the  
parameters be extended?

Do any offer/answer considerations need to be defined?

Colin

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