RFC 2658 (rfc2658) - Page 1 of 10

RTP Payload Format for PureVoice(tm) Audio

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Network Working Group                                           K. McKay
Request for Comments: 2658                         QUALCOMM Incorporated
Category: Standards Track                                    August 1999


               RTP Payload Format for PureVoice(tm) Audio

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 (1999).  All Rights Reserved.

ABSTRACT

   This document describes the RTP payload format for PureVoice(tm)
   Audio.  The packet format supports variable interleaving to reduce
   the effect of packet loss on audio quality.

1 Introduction

   This document describes how compressed PureVoice audio as produced by
   the Qualcomm PureVoice CODEC [1] may be formatted for use as an RTP
   payload type.  A method is provided to interleave the output of the
   compressor to reduce quality degradation due to lost packets.
   Furthermore, the sender may choose various interleave settings based
   on the importance of low end-to-end delay versus greater tolerance
   for lost packets.

   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 [3].

2 Background

   The Electronic Industries Association (EIA) & Telecommunications
   Industry Association (TIA) standard IS-733 [1] defines an audio
   compression algorithm for use in CDMA applications.  In addition to
   being the standard CODEC for all wireless CDMA terminals, the
   Qualcomm PureVoice CODEC (a.k.a. Qcelp) is used in several Internet
   applications most notably JFax(tm), Apple(r) QuickTime(tm), and
   Eudora(r).



K. McKay                    Standards Track
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