Additional WebRTC Audio Codecs for Interoperability
RFC 7875

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Internet Engineering Task Force (IETF)                    S. Proust, Ed.
Request for Comments: 7875                                        Orange
Category: Informational                                         May 2016
ISSN: 2070-1721

          Additional WebRTC Audio Codecs for Interoperability

Abstract

   To ensure a baseline of interoperability between WebRTC endpoints, a
   minimum set of required codecs is specified.  However, to maximize
   the possibility of establishing the session without the need for
   audio transcoding, it is also recommended to include in the offer
   other suitable audio codecs that are available to the browser.

   This document provides some guidelines on the suitable codecs to be
   considered for WebRTC endpoints to address the use cases most
   relevant to interoperability.

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 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/rfc7875.

Proust                        Informational                     [Page 1]
RFC 7875             WebRTC Audio Codecs for Interop            May 2016

Copyright Notice

   Copyright (c) 2016 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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Definitions and Abbreviations . . . . . . . . . . . . . . . .   3
   3.  Rationale for Additional WebRTC Codecs  . . . . . . . . . . .   4
   4.  Additional Suitable Codecs for WebRTC . . . . . . . . . . . .   5
     4.1.  AMR-WB  . . . . . . . . . . . . . . . . . . . . . . . . .   5
       4.1.1.  AMR-WB General Description  . . . . . . . . . . . . .   5
       4.1.2.  WebRTC-Relevant Use Case for AMR-WB . . . . . . . . .   5
       4.1.3.  Guidelines for AMR-WB Usage and Implementation with
               WebRTC  . . . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  AMR . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
       4.2.1.  AMR General Description . . . . . . . . . . . . . . .   6
       4.2.2.  WebRTC-Relevant Use Case for AMR  . . . . . . . . . .   7
       4.2.3.  Guidelines for AMR Usage and Implementation with
               WebRTC  . . . . . . . . . . . . . . . . . . . . . . .   7
     4.3.  G.722 . . . . . . . . . . . . . . . . . . . . . . . . . .   7
       4.3.1.  G.722 General Description . . . . . . . . . . . . . .   7
       4.3.2.  WebRTC-Relevant Use Case for G.722  . . . . . . . . .   8
       4.3.3.  Guidelines for G.722 Usage and Implementation with
               WebRTC  . . . . . . . . . . . . . . . . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  12
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  12
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  12

Proust                        Informational                     [Page 2]
RFC 7875             WebRTC Audio Codecs for Interop            May 2016

1.  Introduction

   As indicated in [OVERVIEW], it has been anticipated that WebRTC will
   not remain an isolated island and that some WebRTC endpoints will
   need to communicate with devices used in other existing networks with
   the help of a gateway.  Therefore, in order to maximize the
   possibility of establishing the session without the need for audio
   transcoding, it is recommended in [RFC7874] to include in the offer
   other suitable audio codecs beyond those that are mandatory to
   implement.  This document provides some guidelines on the suitable
   codecs to be considered for WebRTC endpoints to address the use cases
   most relevant to interoperability.