Subject: [clue] Support for switched multi streams

From: "Roni Even" <[email-masked]>
Date: Tue, 26 Jun 2012 14:21:19 +0200

Hi,

When looking at the RTP mapping and support for multiple streams I was
wondering about what media capture is available in the multipoint case. The
proposals in draft-pepperell-clue-switched-attribute and
draft-hansen-clue-consumer-layout are looking at a subset of a more general
case where all the information about all the participants will be needed,
something that is addressed toady in the conference event package as the
participants-endpoint-media information. The reason is to allow the user
(the real person) to select what it wants to view regardless if this is done
by the local endpoint mixing or the MCU mixing.

The questions I asked myself were:

1.       What media captures or capture scene are sent to each participant
in a multipoint conference. Is it just the virtual room from the MCU or a
combination of all rooms. 

2.       Will the MCU as provider create a subset of media captures from all
rooms as an MCU virtual room or will it provide multiple capture scenes
representing the various participants.

3.       If the capture scenes from all the TP rooms should be available to
all participants, which is probably needed for endpoint mixing but also for
user selection, what is the right way to send the information. Is it Clue
advertisement (above bullet) or by extending the  conference event package
adding to the media also the media capture information.

The reason for these questions is because we are now discussing endpoint
mixing and a requirement to provide information about all the participants. 

For the general case for allowing the maximum flexibility for the consumer
to decide what and how to render, my personal view is that since the
information about the media capture can be large and will change when
parties join or leave the conference it will be good to extend the
conference event package to distribute this information from the MCU. The
MCU will send in the CLUE message the virtual room advertisement while the
capture scenes that the MCU receives from all participants will be available
by subscribing to the event package. 

Roni