APC numbers

Sakae OKUBO okubo at GCTECH.CO.JP
Wed Mar 25 17:26:14 EST 1998

ITU and MPEG Particpants,

Two days ago I sent a message noting the achievement
of H.263 compatibility in MPEG-4 video.  I want to
clarify one aspect of that message.  In my exuberance
over the outcome of the Tokyo MPEG meeting, I may have
glossed over describing the precise resulting technical
relationship between the two standards.  This was
pointed out to me in a private email message.

To clarify, the MPEG-4 video syntax was altered in Tokyo
so that an MPEG-4 video decoder can decode H.263 Baseline
bitstreams.  However, since the MPEG-4 video syntax can
also support additional features not supported in H.263
Baseline syntax, the opposite is not true in general --
not all MPEG-4 video streams can be decoded by H.263
Baseline decoders.  (This is probably understood by those
of us who have intimate knowledge of these standards, but
may need to be clarified for others.)

Best Wishes,

Gary Sullivan

From:    Gary Sullivan <garys at pictel.com>
Subject: MPEG-4 Compatibility with ITU-T H.263

In Re: Compatibility between MPEG-4 Video and ITU-T Rec. H.263:

I wish to take note of what I believe to be an important milestone
in video coding standardization.  Last week, the MPEG-4 project
achieved compatibility with ITU-T H.263.

MPEG created a "final committee draft" of its draft MPEG-4 video
coding standard last week (March 16-20) at its 43rd meeting in
Tokyo.  Full compatibility with the prior video coding standard
ITU-T Recommendation H.263 was adopted into that draft.  The
compatibility was achieved by an alignment of complete syntax
support for the primary "Baseline" interoperability operational
mode of Rec. H.263.  This is an important event in video coding
standardization development, ensuring that the new
implementations of the future MPEG-4 video standard (FCD for
ISO/IEC 14496-2) can have full compatibility with the deployed
implementations of Rec. H.263 worldwide.  This action sends a
clear message that H.263 technology remains at the heart of today's
understanding of low bit-rate video compression coding, and that
interoperability of these standardized systems is needed world-wide.

ITU-T Recommendation H.263 is a video coding standard developed by
the International Telecommunications Union (Telecommunications
Standardization Sector, formerly CCITT).  It was originally approved
in November of 1995 and is maintained by the ITU-T Advanced Video
Coding Experts Group, formally chartered as Question 15 of the ITU-T
Study Group 16 for Multimedia Standardization.  Newly approved in a
second-generation specification completed in September of 1997 and
approved in January of 1998, Rec. H.263 is the current "flagship"
ITU standard for low bit rate video communication coding.  The
"Baseline" mode which forms the heart of H.263 operation was
the fundamental requirement for all implementations of the original
H.263 specification and is now also fully supported in both the
second version of H.263 and in the new draft of MPEG-4 video.  The
H.263 Baseline mode provides an excellent interoperable common core
for video coding systems.

MPEG-4 video, to be formalized in ISO/IEC 14496-2, is a project of
the Moving Picture Experts Group (MPEG) formally chartered as
Working Group 11 of ISO/IEC JTC1 SC29.  The MPEG-4 video coding
standardization project is developing its specification to provide
a broadly-applicable and flexible set of video coding tools and
defined configuration profiles for a wide range of multimedia
applications with new functionalities such as object-segmented
coding and the handling of hybrids of natural and synthetic content.
The first of two planned versions of MPEG-4 video is now in a
"final committee draft" stage and is expected to receive final
approval in December of 1998.

I want to thank those who helped bring about this important
convergence of standardization development.  In particular I would
like to thank the MPEG convenor Mr. Leonardo Chiariglione, the MPEG
Video chairman Mr. Thomas Sikora, the MPEG Video Coding Efficiency
chairman Mr. T. K. Tan, and the supporting MPEG National Bodies of
Canada, France, Norway, and the Netherlands.  I also wish
to especially thank those individuals who recently actively
contributed toward the final detailed technical evaluation, proposal,
and drafting process for this effort, in particular especially
Ms. Gunn Kristin Klungsoyr, Mr. Cor Quist, Mr. Aasmand Sandvand,
Mr. Peter List, and Ms. Cecille Dufour.  I also wish to thank those
who contributed toward this goal previously at critical moments, in
partular Mr. Robert Danielsen, Mr. Tom-Ivar Johansen, Mr. Richard
Schaphorst, Prof. Faouzi Kossentini, and Mr. Jan De Lameillieure.


Gary Sullivan
ITU-T Advanced Video Coding Rapporteur
PictureTel Corporation

This is not an official statement of PictureTel or of ITU-T Q15/SG16.

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