Re: [MMUSIC] Fwd: New Version Notification for draft-abhishek-mmusic-overlay-grouping-00.txt

[Rohit Abhishek <[e-mail]>]

Hi Christer,

Thanks for reading the draft and your reviews. I really appreciate your feedback. The questions here suggest more explanatory text about motivation is needed. I will address these in the next version.

From: Christer Holmberg <[e-mail]>
Date: Thursday, October 29, 2020 at 7:46 AM
To: Rohit Abhishek <[e-mail]>, "[e-mail]" <[e-mail]>
Subject: RE: [MMUSIC] Fwd: New Version Notification for draft-abhishek-mmusic-overlay-grouping-00.txt

Hi Rohit,

A few initial questions for clarifications:
RA: The assumption here is for an immersive telepresence session, one immersive video will be transmitted, whereas other streams will be transmitted as overlays. For ex, consider 10 people in a conference call; a user may stream an immersive video from one user, whereas 2D videos as overlays from other 8 participants (plus additional streams if any participant shares any additional media) . The total overlay streams may vary, for example, a session with a large number of audiences.

Q1:                      The draft references the telepresence use-case spec (RFC7205), but there is no text on why the actual CLUE mechanism isn’t feasible for what you want to do.
RA: I had referred to RFC7205 for definition purposes. CLUE enables interoperability between telepresence systems by exchanging information about the systems’ characteristics. Here, the cameras and screens may be arranged to provide a panoramic view of the remote room.  However, overlays were not considered in the CLUE mechanism.

Q2:                      It is unclear why you need to group the overlay streams together. If you only want to indicate that a stream is for overlay you can e.g., use an SDP attribute for that. You don’t need grouping.
RA: Of course, when a single or relatively fewer overlays are transmitted, grouping won’t be needed. However, when relatively larger numbers of users are in a session, it may be more favorable to use a grouping framework than using SDP attribute for each stream.

Q3:                      The draft talks about the overlay streams being associated with “immersive video”. But, there is no text about how this immersive video stream is represented, and how the overlay streams are associated with that immersive video stream.
RA: Thanks for the suggestion. I will update this in the next version

Q4:                      I assume the overlay streams can be multiplexed using the BUNDLE mechanism?
RA: There maybe multiple RTP sessions whose streams may have to be grouped. Using BUNDLE mechanism will only allow to group media streams within a single RTP session.  However, multiple media streams from various endpoints may be multiplexed into a single RTP session but would require RTP-level middle boxes. These middle boxes may add delay if a large number of streams are to be multiplexed, which even if very less, may not be favorable for telepresence sessions.


Best Regards,
Rohit



Regards,

Christer

From: mmusic <[e-mail]> On Behalf Of Rohit Abhishek
Sent: keskiviikko 28. lokakuuta 2020 0.23
To: [e-mail]
Subject: [MMUSIC] Fwd: New Version Notification for draft-abhishek-mmusic-overlay-grouping-00.txt


Dear All,



I am currently working on an SDP extension facilitating overlays for immersive telepresence.

An individual draft has been posted at

https://www.ietf.org/archive/id/draft-abhishek-mmusic-overlay-grouping-00.txt



Comments are welcome





Best Regards,

Rohit

---------- Forwarded message ---------
From: <[e-mail]<mailto:[e-mail]>>
Date: Tue, Oct 27, 2020 at 2:56 PM
Subject: New Version Notification for draft-abhishek-mmusic-overlay-grouping-00.txt
To: Rohit Abhishek <[e-mail]<mailto:[e-mail]>>



A new version of I-D, draft-abhishek-mmusic-overlay-grouping-00.txt
has been successfully submitted by Rohit Abhishek and posted to the
IETF repository.

Name:           draft-abhishek-mmusic-overlay-grouping
Revision:       00
Title:          SDP Overlay Grouping framework for immersive telepresence media streams
Document date:  2020-10-27
Group:          Individual Submission
Pages:          8
URL:            https://www.ietf.org/archive/id/draft-abhishek-mmusic-overlay-grouping-00.txt
Status:         https://datatracker.ietf.org/doc/draft-abhishek-mmusic-overlay-grouping/
Htmlized:       https://datatracker.ietf.org/doc/html/draft-abhishek-mmusic-overlay-grouping
Htmlized:       https://tools.ietf.org/html/draft-abhishek-mmusic-overlay-grouping-00


Abstract:
   This document defines semantics that allow for signalling a new SDP
   group "OL" for overlays in an immersive telepresence session.  The
   "OL" attribute can be used by the application to relate all the
   overlay media streams enabling them to be added as overlay on top of
   the immersive video.  The overlay grouping semantics is required, if
   the media data is seperate and transported via different protocols.




Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org<http://tools.ietf.org>.

The IETF Secretariat