Subject: I-D ACTION:draft-finlayson-rtp-mp3-00.txt

From: [email-masked]
Date: Fri, 26 Feb 1999 17:20:15 -0500

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title		: A More Loss-Tolerant RTP Payload Format for MP3 Audio
	Author(s)	: R. Finlayson
	Filename	: draft-finlayson-rtp-mp3-00.txt
	Pages		: 2
	Date		: 24-Feb-99
	
While the RTP payload format defined in RFC 2250 is generally applicable
to all forms of MPEG audio or video, it is less suitable for MPEG 1 or 2,
layer III audio (commonly known as 'MP3').  The reason for this is that
an MP3 frame is not a true 'Application Data Unit' - it contains a
back-pointer to data in earlier frames, and so cannot be decoded
independently of these earlier frames.  Because RFC 2250 defines that packet
boundaries coincide with frame boundaries, it handles packet loss
inefficiently when carrying MP3 data.  The loss of an MP3 frame will render
some data in previous (or future) frames useless, even if they are received
without loss.
 
In this document we define a new RTP payload format for MP3 audio.  The new
format is essentially the same as that defined in RFC 2250, except for a
data-preserving rearrangement of the original MPEG frames, so that packet
boundaries now coincide with true MP3 'Application Data Units'.  This new
format is therefore more data efficient in the face of packet loss.

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