RFC 3389 (rfc3389) - Page 1 of 8
Real-time Transport Protocol (RTP) Payload for Comfort Noise (CN)
Alternative Format: Original Text Document
Network Working Group R. Zopf Request for Comments: 3389 Lucent Technologies Category: Standards Track September 2002 Real-time Transport Protocol (RTP) Payload for Comfort Noise (CN) Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract This document describes a Real-time Transport Protocol (RTP) payload format for transporting comfort noise (CN). The CN payload type is primarily for use with audio codecs that do not support comfort noise as part of the codec itself such as ITU-T Recommendations G.711, G.726, G.727, G.728, and G.722. 1. Conventions Used in This Document 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 [7]. 2. Introduction This document describes a RTP [1] payload format for transporting comfort noise. The payload format is based on Appendix II of ITU-T Recommendation G.711 [8] which defines a comfort noise payload format (or bit-stream) for ITU-T G.711 [2] use in packet-based multimedia communication systems. The payload format is generic and may also be used with other audio codecs without built-in Discontinuous Transmission (DTX) capability such as ITU-T Recommendations G.726 [3], G.727 [4], G.728 [5], and G.722 [6]. The payload format provides a minimum interoperability specification for communication of comfort noise parameters. The comfort noise analysis and synthesis as well as the Voice Activity Detection (VAD) and DTX algorithms are unspecified and left implementation-specific. Zopf Standards Track
