One document matched: draft-wenger-clue-definitions-00.txt
CLUE WG S. Wenger
Internet-Draft Vidyo, Inc.
Intended status: Informational May 19, 2011
Expires: November 20, 2011
CLUE Definitions
draft-wenger-clue-definitions-00.txt
Abstract
This document collects terminology and definitions to be used
consistently among documents produced in the CLUE working group.
Status of this Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on November 20, 2011.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
7. Informative References . . . . . . . . . . . . . . . . . . . . 6
Appendix A. Draft History . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7
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1. Introduction
This document collects terminology and definitions to be used
consistently among documents produced in the CLUE working group. The
draft is intended to be a living document, to be updated as the
working group discussions progress. It is not intended for
publication as an RFC; instead, it is expected that definitions and
terminology defined herein are going to be replicated in other CLUE
documents.
All defined terms herein are captitalized. It is recommended that
authors of other CLUE document follow this conventions when using
definitions from this document.
It should be understood that the definitions herein are not to be
interpreted as antedating design decisions to be made later. It's
entierly reasonable that design choices conflicting with definitions
in this draft may become necessary. In such cases, CLUE document
authors can either request the definition be updated, or can simply
avoid the use of a definition of this document. However, an author
should never use a capitzalied definition as set forth herein with a
different meaning in a different CLUE document.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
3. Definitions
Audio Mixing: refers to the accumulation of scaled audio signals
to produce a single audio stream. See RTP Topologies,
[RFC5117].
Capture Device: A device that converts audio and video input
into an electrical signal, in most cases to be fed into a media
encoder. Cameras and microphones are examples for capture
devices.
Conference: used as defined in [RFC4353], A Framework for
Conferencing within the Session Initiation Protocol (SIP).
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Endpoint: The logical point of final termination through
receiving, decoding and rendering, and/or initiation through
capturing, encoding, and sending of media streams. An endpoint
consists of one or more physical devices which source and sink
media streams, and exactly one [RFC4353] Participant (which, in
turn, includes exactly one SIP User Agent). In contrast to an
endpoint, an MCU may also send and receive media streams, but it
is not the initiator nor the final terminator in the sense that
Media is Captured or Rendered. Endpoints can be anything from
multiscreen/multicamera rooms to handheld devices.
Endpoint Characteristics: include placement of Capture and
Rendering Devices, capture/render angle, resolution of cameras
and screens, spatial location and mixing parameters of
microphones. Endpoint characteristics are not specific to
individual media streams sent by the endpoint.
Layout: How rendered media streams are spatially arranged with
respect to each other on a single screen/mono audio telepresence
endpoint, and how rendered media streams are arranged with
respect to each other on a multiple screen/speaker telepresence
endpoint. Note that audio as well as video is encompassed by
the term layout--in other words, included is the placement of
audio streams on speakers as well as video streams on video
screens. Edit. note: this is on the RENDERER side.
Left: to be interpreted as a stage direction, see also
[StageDirection(Wikipadia)]
Local: Sender and/or receiver physically co-located ("local") in
the context of the discussion.
MCU: Multipoint Control Unit (MCU) - a device that connects two
or more endpoints together into one single multimedia conference
[RFC5117]. An MCU includes an [RFC4353] Mixer. Edt. Note:
RFC4353 is tardy in requireing that media from the mixer be sent
to EACH participant. I think we have practical use cases where
this is not the case. But the bug (if it is one) is in 4353 and
not herein.
Media: Any data that, after suitable encoding, can be conveyed
over RTP, including audio, video or timed text. Edt. note: does
Media include far end camera control (which can be conveyed over
RTP)?
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Model: a set of assumptions a telepresence system of a given
vendor adheres to and expects the remote telepresence system(s)
also to adhere to.
Remote: Sender and/or receiver on the other side of the
communication channel (depending on context); not Local. A
remote can be an Endpoint or an MCU.
Render: the process of generating a representation from a media,
such as displayed motion video or sound emitted from
loudspeakers.
Rendering Device: A device that converts an electrical signal -
in most cases stemming from a media decoder - to audible and
optical signals. Screens and loudspeakers are examples for
rendering devices.
Right: to be interpreted as stage direction, see also
[StageDirection(Wikipadia)]
Source selection policies: rules for determining which media
source(s) to play or show.
Spatial Relation: The arrangement in space of two objects, in
contrast to relation in time or other relationships. See also
Left and Right.
Stream Characteristics: include media stream attributes commonly
used in non-CLUE SIP/SDP environments (such as: media codec, bit
rate, resolution, profile/level etc.) as well as CLUE specific
attributes (which could include for example and depending on the
solution found: the I-D or spatial location of a capture device
a stream originates from).
Telepresence: an environment that gives non co-located users or
user groups a feeling of (co-located) presence - the feeling
that a Local user is in the same room with other Local users and
the Remote parties. The inclusion of Remote parties is achieved
through multimedia communication including at least audio and
video signals of high fidelity.
Video composite: A single image that is formed from combining
visual elements from separate sources.
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4. Acknowledgements
Most of this stuff is copied from the CLUE requirements draft. Go
there to look at dignitaries.
5. IANA Considerations
None
6. Security Considerations
None
7. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5117] Westerlund, M. and S. Wenger, "RTP Topologies", RFC 5117,
January 2008.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003.
[RFC4353] Rosenberg, J., "A Framework for Conferencing with the
Session Initiation Protocol (SIP)", RFC 4353,
February 2006.
[StageDirection(Wikipadia)]
Wikipedia, "Blocking (stage), available from http://
en.wikipedia.org/wiki/Stage_direction#Stage_directions",
May 2011, <http://en.wikipedia.org/wiki/
Stage_direction#Stage_directions>.
Appendix A. Draft History
00: Initial version; mostly copy-past from requirements-02.
Removed "session". Editors are advised to be specific about SIP,
RTP, or whatever else sessions.
Made clear that Layout refers to rendering, not capturing.
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added Left, Right, in stage direction, w/ Wikipedia reference
Author's Address
Stephan Wenger
Vidyo, Inc.
433 Hackensack Ave., 7th Floor
Hackensack, NJ 07601
USA
Email: stewe@stewe.org
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