RTP Control Protocol (RTCP) Extended Report (XR) Blocks for Concealment Metrics Reporting on Audio Applications
RFC 7294
Internet Engineering Task Force (IETF) A. Clark
Request for Comments: 7294 Telchemy
Category: Standards Track G. Zorn
ISSN: 2070-1721 Network Zen
C. Bi
STTRI
Q. Wu
Huawei
July 2014
RTP Control Protocol (RTCP) Extended Report (XR) Blocks
for Concealment Metrics Reporting on Audio Applications
Abstract
This document defines two RTP Control Protocol (RTCP) Extended Report
(XR) blocks that allow the reporting of concealment metrics for audio
applications of RTP.
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 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7294.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Clark, et al. Standards Track [Page 1]
RFC 7294 RTCP XR Concealment July 2014
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Loss Concealment and Concealed Seconds Metrics
Blocks . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. RTCP and RTCP Extended Reports . . . . . . . . . . . . . 3
1.3. Performance Metrics Framework . . . . . . . . . . . . . . 4
1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Standards Language . . . . . . . . . . . . . . . . . . . 4
2.2. Notations . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Loss Concealment Metrics Block . . . . . . . . . . . . . . . 5
3.1. Report Block Structure . . . . . . . . . . . . . . . . . 5
3.2. Definition of Fields in Loss Concealment Metrics Block . 5
4. Concealed Seconds Metrics Block . . . . . . . . . . . . . . . 9
4.1. Report Block Structure . . . . . . . . . . . . . . . . . 10
4.2. Definition of Fields in Concealed Seconds Metrics Block . 10
5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . 14
5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . 14
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
6.1. New RTCP XR Block Type Values . . . . . . . . . . . . . . 14
6.2. New RTCP XR SDP Parameters . . . . . . . . . . . . . . . 15
6.3. Contact Information for Registrations . . . . . . . . . . 15
7. Security Considerations . . . . . . . . . . . . . . . . . . . 15
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 15
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
10.1. Normative References . . . . . . . . . . . . . . . . . . 16
10.2. Informative References . . . . . . . . . . . . . . . . . 16
Appendix A. Metrics Represented Using the Template from RFC 6390 17
1. Introduction
1.1. Loss Concealment and Concealed Seconds Metrics Blocks
At any instant, the audio output at a receiver may be classified as
either 'normal' or 'concealed'. 'Normal' refers to playout of audio
payload received from the remote end and also includes locally
generated signals such as announcements, tones, and comfort noise.
'Concealed' refers to playout of locally generated signals used to
mask the impact of network impairments or to reduce the audibility of
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