CLUE WG S. Wenger Internet-Draft Vidyo, Inc. Intended status: Informational July 12, 2011 Expires: January 13, 2012 CLUE Definitions draft-wenger-clue-definitions-01.txt Abstract This document collects terminology and definitions to be used consistently among documents produced in the CLUE working group. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 13, 2012. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Wenger Expires January 13, 2012 [Page 1] Internet-Draft CLUE Definitions July 2011 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 Wenger Expires January 13, 2012 [Page 2] Internet-Draft CLUE Definitions July 2011 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, microphones, and keyboards are examples for capture devices. Conference: used as defined in [RFC4353], A Framework for Conferencing within the Session Initiation Protocol (SIP). Wenger Expires January 13, 2012 [Page 3] Internet-Draft CLUE Definitions July 2011 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/loudspeaker 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 loudspeakers as well as video streams on video screens. Edit. note: this is on the RENDERER side. Left: to be interpreted in the context of the description where the word occurs." Edt. note: there has been a lot of mailing list discussions about "left" and "right", and we seem not to be able to arrive at a common understanding. Local: Sender and/or receiver physically co-located ("local", "in the same room") 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)? Wenger Expires January 13, 2012 [Page 4] Internet-Draft CLUE Definitions July 2011 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. Participant: to be interpreted as defined in RFC 4353 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 visual signals. Screens and loudspeakers are examples for rendering devices. Right: to be interpreted in the context of the description where the word occurs."/> 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. "Telepresence Extensions": The protocol extensions beyond SIP adn its extensions defined as of July 2011, specified by RFC XXXX. (XXX to be replaced by the RFC editor with any documents developed by the CLUE WG that contain normative content, such as architecture, protocol specification, and whatnot.) Wenger Expires January 13, 2012 [Page 5] Internet-Draft CLUE Definitions July 2011 Video composite: A single image that is formed from combining visual elements from separate sources. 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, . Appendix A. Draft History 01: removed "stage direction" in "left" "right". Replaced with "to be interpreted in context". Wenger Expires January 13, 2012 [Page 6] Internet-Draft CLUE Definitions July 2011 clarified "local" to mean "in the same room" per J. Polk email 6/14/11 Consistently refer to "loudspeaker" per Christer's email 6/13/11 Added "keyboard" to listed caputure devices per Christer's email 6/13/11 Rendering device: changed "optical" to "visual". Hope Christer finds this OK. Per Christer's email 6/13/11 Note: the other changes proposed by Christer in his 6/13 email appear to change more than just words but semantics. Not included here as such semantic changes are best handled in the requirement and other docs. Edt. Note: there have been lengthily discussions about the term "Participant". One camp wanted the word to refer to human users of telepresence equipment so to use intuitive language, the other (as this document) suggests to use the word in the RFC Participant defined as per RFC 4353. I think this is what we arrived at on the mailing list, right? Added "Telepresence Extensions" per long "solutions" thread. 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. 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 Wenger Expires January 13, 2012 [Page 7]