RTP Payload Format for Vorbis Encoded Audio
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From: The IESG <email@example.com> To: IETF-Announce <firstname.lastname@example.org> Cc: Internet Architecture Board <email@example.com>, RFC Editor <firstname.lastname@example.org>, avt mailing list <email@example.com>, avt chair <firstname.lastname@example.org> Subject: Protocol Action: 'RTP Payload Format for Vorbis Encoded Audio' to Proposed Standard The IESG has approved the following document: - 'RTP Payload Format for Vorbis Encoded Audio ' <draft-ietf-avt-rtp-vorbis-10.txt> as a Proposed Standard This document is the product of the Audio/Video Transport Working Group. The IESG contact persons are Cullen Jennings and Jon Peterson. A URL of this Internet-Draft is: http://www.ietf.org/internet-drafts/draft-ietf-avt-rtp-vorbis-10.txt
Technical Summary This document describes an RTP payload format for transporting Vorbis encoded audio. It details the RTP encapsulation mechanism for raw Vorbis data and details the delivery mechanisms for the decoder probability model, referred to as a codebook and other setup information. Also included within this memo are media type registrations, and the details necessary for the use of Vorbis with the Session Description Protocol (SDP). Working Group Summary The RTP payload format for Vorbis has been under discussion since the 50th IETF meeting and has changed author several times (which has delayed its progress). The main technical issue has been transport of configuration headers: Vorbis doesn't use statically configured code books, and must receive a configuration header containing appropriate code books for a stream before it can begin decoding. This is problematic for RTP sessions using unreliable transports with limited packet size, and required definition of both in-band and out-of-band access methods for configuration headers, to ensure the configured data can be retrieved. Document Quality There are a number of implementations. The media type review request was posted 11 June 2007. During the media type review, Bjoern Hoehrmann and Chris Lilley expressed concern that this draft registers the audio/vorbis media type for use only with RTP. We believe this concern is misplaced, since Vorbis data must be framed (the application/ogg container provides the framing for non-RTP use) and the registration of an RTP-only media type is consistent with current practice, as documented in RFC 4855. Personnel Colin Perkins is the document shepherd. Cullen Jennings is a responsible area director.