Subject: [dispatch] Telepresence charter version 6

From: "Allyn Romanow (allyn)" <[email-masked]>
Date: Mon, 25 Oct 2010 15:58:49 -0700

In preparation for discussion in DISPATCH meeting, here are the changes
since the last draft. They include:

Changes from Version 5

*         Editorial comments from Jonathan Lennox

*         Christer Holmberg - "In addition, standardization work, in
order to be able to exchange semantic information about what each media
stream represents, might be needed."

      Propose leave out sentence

*         Magnus Westerlund - include transmitting system, add WG
chartered to make requirements for TP interoperability to distribute or
handle as appropriate

*         Ted Hardie - early milestone, use case without participants
(use case draft)

*         Minor editorial changes

------------------------

MAITAI - Multi-stream Attributes for Improving Telepresence Application
Interoperability

CLUE -- ControLling mUltiple streams for tElepresence

In the context of this WG, the term telepresence is used in a general
manner to describe systems that provide high definition, high quality
audio/video enabling a "being-there" experience.  One example is an
immersive telepresence system using specially designed and special
purpose rooms with multiple displays permitting life size image
reproduction using multiple cameras, encoders, decoders, microphones and
loudspeakers.

Current telepresence systems are based on open standards such as RTP,
SIP, H.264, the H.323 suite. However, they cannot easily interoperate
with each other without operator assistance and expensive additional
equipment which translates from one vendor to another. A major factor
limiting the interoperability of telepresence systems  is the lack of a
standardized way to describe and negotiate the use of the multiple
streams of audio and video comprising the media flows.

The WG will create specifications for SIP-based conferencing systems to
enable communication of  information about media streams so that a
sending system,  receiving system, or intermediate system can make
reasonable decisions about transmitting, selecting, and rendering media
streams. This enables systems to make choices that optimize user
experience.

This working group is chartered to specify  information about media
streams from one entity to another entity: 

* Spatial relationships of cameras, displays, microphones, and speakers
- relative to each other and to likely positions of participants

* Specific characteristics such as viewpoint, field of view/capture for
camera/microphone/display/speaker - so that senders and intermediate
devices can understand how best to compose streams for receivers, and
the receiver will know the characteristics of its received streams

* Usage of the stream, for example whether the stream is presentation,
or document camera output

* Aspect ratio of cameras and displays 

*Which sources a receiver wants to receive.  For example, it might  want
the source for the left camera, or might want the source chosen by VAD
(Voice Activity Detection)

Information between sources and sinks about media stream capabilities
will be exchanged. 

The working group will define the semantics, syntax, and transport
mechanism necessary for communicating the necessary information. It will
consider whether the existing signaling mechanisms (e. g., SDP) can be
extended, or another messaging method should be used.  

The scope of the work includes describing relatively static relations
between entities (participants and devices). It also includes handling
more dynamic relationships, such as identifying the audio and video
streams for the current speaker. The scope includes both systems that
provide a fully immersive experience, and systems that interwork with
them and therefore need to understand the same multiple stream
semantics.  

The focus of this work is on multiple audio and video streams.  Other
media types may be considered, however development of methodologies for
them is not within the scope of this work.

Interoperation with SIP and related standards for audio and video is
required.  However, backwards compatibility with existing non-standards
compliant telepresence systems is not required.

This working group is not currently chartered to work on issues of
continuous conference control including: far end camera control,
indication of fast frame update for video codecs or other rapid
switches, floor control, conference roster. The working group may
identify interoperability obstacles in existing open standards. If so,
the WG will develop requirements to be communicated to other IETF WGs or
Standards Forums, or recharter as appropriate.

Reuse of existing protocols and backwards compatibility with
SIP-compliant audio/video endpoints are important factors for the
working group to consider. The work will closely coordinate with the
appropriate areas (e. g., OPS, SEC), and working groups including  AVT,
MMUSIC, MEDIACTRL, XCON, and SIPCORE.

 Milestones  

July 2011 Submit informational draft to IESG on use cases 

July 2011 Submit informational draft to IESG on framework and
requirements

Nov 2011 Submit standards track specification(s) to IESG to support
framework and requirements