Subject: [MMUSIC] Displaying side by side video streams draft-jennings-mmusic-adjacent-grouping

From: Cullen Jennings <[email-masked]>
Date: Tue, 21 Sep 2010 13:49:11 -0600

I just submitted a draft on using the SDP grouping framework to indicate when multiple media streams should be rendered side by side. It a pretty trivial draft but I'd love to get some comments on it. 

http://www.ietf.org/id/draft-jennings-mmusic-adjacent-grouping-00.txt

Thanks, Cullen

---

From: "Roni Even" <[email-masked]>
Date: Thu, 23 Sep 2010 01:46:17 +0200

Hi Cullen,
I agree that it is a very trivial draft and have some value if the
limitation are described. 
Reading the draft I assume that when you say a screen it means a camera and
a monitor pair. If this is not the case how do you signal this information
(cameras and monitors)  and how does the answerer describes his topology if
it is not the same as the offer, is it based on sendonly and recvonly offers
and answers.

It will work well in a symmetrical case, I am not sure about the other
cases. For example if the offer has three cameras (and three monitors) and
the other side has two screens by selecting two in the answer he will only
get two of the streams. What if he wants to switch between the streams
watching different ones, will it require a re-invite or will he answer with
the three streams and switch to the display the ones he wants to display at
the moment.

Roni Even

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On
> Behalf Of Cullen Jennings
> Sent: Tuesday, September 21, 2010 9:49 PM
> To: MMUSIC WG
> Subject: [MMUSIC] Displaying side by side video streams draft-jennings-
> mmusic-adjacent-grouping
> 
> 
> I just submitted a draft on using the SDP grouping framework to
> indicate when multiple media streams should be rendered side by side.
> It a pretty trivial draft but I'd love to get some comments on it.
> 
> _______________________________________________
> mmusic mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/mmusic

---

From: "Allyn Romanow (allyn)" <[email-masked]>
Date: Fri, 24 Sep 2010 21:57:06 -0700

Hi Cullen,

Your suggested approach seems promising - to use grouping, but the
problem you are focused on seems to me to be just one aspect of what is
necessary to address if you want to handle multiple streams in a
Telepresence conference. I wonder how you see this proposal in relation
to the proposed Telepresence work currently under charter discussion in
DISPATCH? 
Given your example application is multiple screen Telepresence systems,
it seems like there is considerable overlap. 

I'm cc'ing the DISPATCH list as some folks there who might be interested
may not follow mmusic.

Best-
Allyn

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf
Of Cullen Jennings (fluffy)
Sent: Tuesday, September 21, 2010 12:49 PM
To: MMUSIC WG
Subject: [MMUSIC] Displaying side by side video
streamsdraft-jennings-mmusic-adjacent-grouping

I just submitted a draft on using the SDP grouping framework to indicate
when multiple media streams should be rendered side by side. It a pretty
trivial draft but I'd love to get some comments on it. 

Thanks, Cullen

---

From: Cullen Jennings <[email-masked]>
Date: Wed, 29 Sep 2010 14:16:27 -0600

Thanks Roni - good point. Comments inline....

> it is not the same as the offer, is it based on sendonly and recvonly offers

Tried to clear that up a bit - I had the text sort of wrong. When SDP goes from A to B, regardless of if it is an offer or answer, the SDP should indicate what the preferred adjacency grouping is of the media that A will send to B. 

> the three streams and switch to the display the ones he wants to display at

It would allow either of the above behaviors thought neither of them are the ideal solution for cases with rapid switching. Clearly the re-invite is not exactly the fast way to switch and the sending 3 streams when you are only displaying 2 is a waste of bandwidth. I don't think this draft is really trying to take on the problems of the fast switching though I hope some other draft does.

---

From: Cullen Jennings <[email-masked]>
Date: Wed, 29 Sep 2010 14:17:47 -0600

Yah, as I explained in my other email, there are many more problems in telepresence than just this adjacency. Check out my email to Ingemar Johansson and see if that helps clear things up.  That was part of the reason I called this adjacency instead of position. I removed the word telepresence from the draft.