RTP Timestamp Frequency for Variable Rate Audio Codecs

Document Type Expired Internet-Draft (avt WG)
Authors Stephan Wenger  , Colin Perkins 
Last updated 2004-10-19
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
pdf htmlized (tools) htmlized bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This memo discusses the problems of audio codecs with variable external sampling rates. Historically, for audio codecs, the RTP timestamp frequency was chosen to match the sampling rate of the audio codec. However, this choice is nowadays more difficult to justify, because of the advent of audio codecs (and, even more important, practical use cases) that support multiple sample rates and the switch between the sample rates during the lifetime of an RTP session. This Internet draft addresses the problem by suggesting that RTP Payload RFCs for such codecs to utilize a single, high, unified RTP timestamp frequency.


Stephan Wenger (stewe@stewe.org)
Colin Perkins (csp@csperkins.org)

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)