Subject: [clue] comments on draft-ietf-clue-framework-01

From: Paul Kyzivat <[email-masked]>
Date: Fri, 11 Nov 2011 10:49:17 -0500

I reviewed draft-ietf-clue-framework-01 again in prep for the meeting.
The following are things I noted along the way:

Definitions:

I think we need to define "Telepresence Session" and "Telepresence 
Conference". The former encompasses both point-to-point and MCU based 
sessions, the latter is just those involving an MCU.

Are both Capture Scene and Capture Set necessary? They are 1:1.

Conference: are we interested in the sort of distributed conference 
contemplated by dcon? Can we leave that out of scope until dcon is well 
underway?

Is the word "configure" appropriate? Would "select" be more appropriate?

5 Stream Information:

Perhaps the section title is a misnomer. This is more than stream info. 
Suggest "Media Provider Information".

I thought we agreed that we would allow attributes at the capture set 
level. But while that has been added in section 5.5, it hasn't been 
added to the figure.

It would also be good to add another level to the top of this hierarchy 
(Provider) and show that the provider can have multiple capture sets.

5.3 Attributes for media captures:

ISTM that "purpose" should be an attribute of a 
capture-scene/capture-set, because all the captures in a given scene 
should have the same purpose.

5.3.3 Audio Channel Format:

    All ACs in the same row of a Capture Set MUST have the same value of
    the "channel format" attribute.

Rather than such a constraint, I suggest making this an attribute of the 
capture set row itself, rather than of an individual capture. (That 
means introducing the capture set row as and explicit element of the 
model. And I think we could improve on "row" as the term for this. What 
about something like "view" (in the DB sense).)

5.3.4 Area of capture

The definition of the axes differs from the slides. (Y and Z are swapped.)

5.4 Capture Set

    The idea is to have sets of captures that represent the same
    information ("information" in this context might be a set of people
    and their associated audio / video streams, or might be a
    presentation supplied by a laptop, perhaps with an accompanying audio
    commentary).  Spatial ordering of media captures is described through
    the use of attributes.

This is not as comprehensible as it might be, because it fails to 
reference "capture scene", which has been defined and is what it is 
talking about. How about:

    The idea is to have sets of captures that represent the same
    capture scene.  Spatial ordering of media captures is described
    through the use of attributes.

6.2. Physical Simultaneity

    Physical or device simultaneity refers to fact that a device may not
    be able to be used in different ways at the same time.  This shapes
    the way that offers are made from the provider.  The offers are made
    so that the consumer will choose one of several possible usages of
    the device.

The use of "offers" above seems less than ideal. How about:

    Physical or device simultaneity refers to fact that a device may not
    be able to be used in different ways at the same time.  This shapes
    the way that capabilities are announced by the provider.  The
    announcement is structured so that the consumer will choose one of
    several possible usages of the device.

	Thanks,
	Paul