Subject: I-D ACTION:draft-ietf-avt-rtp-h263-video-01.txt

From: [email-masked]
Date: Thu, 15 Jan 1998 11:43:16 -0500

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Audio/Video Transport Working Group of the IETF.

	Title		: RTP Payload Format for the 1998 Version of ITU-T Rec. H.263 Video (H.263+)
	Author(s)	: C. Maciocco, J. Ott, C. Bormann, C. Zhu, L. Cline, D. Newell, G. Sullivan, G. Deisher, S. Wenger
	Filename	: draft-ietf-avt-rtp-h263-video-01.txt
	Pages		: 10
	Date		: 14-Jan-98
	
This document specifies an RTP payload header format applicable to the
transmission of video streams generated based on the 1998 version of
ITU-T Recommendation H.263 [4].  Because the 1998 version of H.263 is a
superset of the 1996 syntax, this format can also be used with the 1996
version of H.263.
 
The 1998 version of ITU-T Recommendation H.263 added numerous coding
options to improve codec performance over the 1996 version.  The 1998
version is referred to as H.263+ in this document.  Among the new
options, the ones with the biggest impact on the RTP payload
specification and the error resilience of the video content are the
slice structured mode, the independent segment decoding mode (ISD), the
reference picture selection mode, and the scalability mode.  This
section summarizes the impact of these new coding options on
packetization.  Refer to [4] for more information on coding options.
 
The slice structured mode was added to H.263+ for three purposes: to
provide enhanced error resilience capability, to make the bitstream more
amenable to use with an underlying packet transport such as RTP, and to
minimize video delay.  The slice structured mode supports fragmentation
at macroblock boundaries.

With the independent segment decoding option, a video picture frame is
broken into segments and encoded in such a way that each segment is
independently decodable.  Utilizing ISD in a lossy network environment
helps to prevent the propagation of errors from one segment of the
picture to others.
 
The reference picture selection mode allows the use of an older
reference picture rather than the one immediately preceding the current
picture.  Usually, the last transmitted frame is implicitly used as the
reference picture for inter-frame prediction.  If the reference picture
selection mode is used, the data stream carries information on what
reference frame should be used, indicated by the temporal reference as
an ID for that reference fra

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