Requirements for an Internet Audio Codec
RFC 6366
Internet Engineering Task Force (IETF) J. Valin
Request for Comments: 6366 Mozilla
Category: Informational K. Vos
ISSN: 2070-1721 Skype Technologies, S.A.
August 2011
Requirements for an Internet Audio Codec
Abstract
This document provides specific requirements for an Internet audio
codec. These requirements address quality, sampling rate, bit-rate,
and packet-loss robustness, as well as other desirable properties.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see 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/rfc6366.
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.
Valin & Vos Informational [Page 1]
RFC 6366 Audio Codec Requirements August 2011
Table of Contents
1. Introduction ....................................................2
2. Definitions .....................................................3
3. Applications ....................................................3
3.1. Point-to-Point Calls .......................................3
3.2. Conferencing ...............................................4
3.3. Telepresence ...............................................5
3.4. Teleoperation and Remote Software Services .................5
3.5. In-Game Voice Chat .........................................5
3.6. Live Distributed Music Performances / Internet
Music Lessons ..............................................6
3.7. Delay-Tolerant Networking or Push-to-Talk Services .........6
3.8. Other Applications .........................................7
4. Constraints Imposed by the Internet on the Codec ................7
5. Detailed Basic Requirements .....................................8
5.1. Operating Space ............................................9
5.2. Quality and Bit-Rate .......................................9
5.3. Packet-Loss Robustness ....................................10
5.4. Computational Resources ...................................10
6. Additional Considerations ......................................12
6.1. Low-Complexity Audio Mixing ...............................12
6.2. Encoder Side Potential for Improvement ....................12
6.3. Layered Bit-Stream ........................................13
6.4. Partial Redundancy ........................................13
6.5. Stereo Support ............................................13
6.6. Bit Error Robustness ......................................13
6.7. Time Stretching and Shortening ............................14
6.8. Input Robustness ..........................................14
6.9. Support of Audio Forensics ................................14
6.10. Legacy Compatibility .....................................14
7. Security Considerations ........................................14
8. Acknowledgments ................................................15
9. Informative References .........................................15
1. Introduction
This document provides requirements for an audio codec designed
specifically for use over the Internet. The requirements attempt to
address the needs of the most common Internet interactive audio
transmission applications and ensure good quality when operating in
conditions that are typical for the Internet. These requirements
also address the quality, sampling rate, delay, bit-rate, and packet-
loss robustness. Other desirable codec properties are considered as
Show full document text