Framework for Telepresence Multi-Streams
RFC 8845
Internet Engineering Task Force (IETF) M. Duckworth, Ed.
Request for Comments: 8845
Category: Standards Track A. Pepperell
ISSN: 2070-1721 Acano
S. Wenger
Tencent
January 2021
Framework for Telepresence Multi-Streams
Abstract
This document defines a framework for a protocol to enable devices in
a telepresence conference to interoperate. The protocol enables
communication of information about multiple media streams so a
sending system and receiving system can make reasonable decisions
about transmitting, selecting, and rendering the media streams. This
protocol is used in addition to SIP signaling and Session Description
Protocol (SDP) negotiation for setting up a telepresence session.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8845.
Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction
2. Requirements Language
3. Definitions
4. Overview and Motivation
5. Description of the Framework/Model
6. Spatial Relationships
7. Media Captures and Capture Scenes
7.1. Media Captures
7.1.1. Media Capture Attributes
7.2. Multiple Content Capture
7.2.1. MCC Attributes
7.3. Capture Scene
7.3.1. Capture Scene Attributes
7.3.2. Capture Scene View Attributes
7.4. Global View List
8. Simultaneous Transmission Set Constraints
9. Encodings
9.1. Individual Encodings
9.2. Encoding Group
9.3. Associating Captures with Encoding Groups
10. Consumer's Choice of Streams to Receive from the Provider
10.1. Local Preference
10.2. Physical Simultaneity Restrictions
10.3. Encoding and Encoding Group Limits
11. Extensibility
12. Examples - Using the Framework (Informative)
12.1. Provider Behavior
12.1.1. Three-Screen Endpoint Provider
12.1.2. Encoding Group Example
12.1.3. The MCU Case
12.2. Media Consumer Behavior
12.2.1. One-Screen Media Consumer
12.2.2. Two-Screen Media Consumer Configuring the Example
12.2.3. Three-Screen Media Consumer Configuring the Example
12.3. Multipoint Conference Utilizing Multiple Content Captures
12.3.1. Single Media Captures and MCC in the Same
Advertisement
12.3.2. Several MCCs in the Same Advertisement
12.3.3. Heterogeneous Conference with Switching and
Composition
12.3.4. Heterogeneous Conference with Voice-Activated
Switching
13. IANA Considerations
14. Security Considerations
15. References
15.1. Normative References
15.2. Informative References
Acknowledgements
Authors' Addresses
1. Introduction
Current telepresence systems, though based on open standards such as
RTP [RFC3550] and SIP [RFC3261], cannot easily interoperate with each
other. A major factor limiting the interoperability of telepresence
systems is the lack of a standardized way to describe and negotiate
the use of multiple audio and video streams comprising the media
flows. This document provides a framework for protocols to enable
interoperability by handling multiple streams in a standardized way.
The framework is intended to support the use cases described in "Use
Cases for Telepresence Multistreams" [RFC7205] and to meet the
requirements in "Requirements for Telepresence Multistreams"
[RFC7262]. This includes cases using multiple media streams that are
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