Prognosemetoder – en oversikt - Telenor

compression modems and terminal aspects. The standard will be
developed in two phases:
- A short term standard complete in 1995. The compression
methods will be “fine tuned” versions of already available
standards. The video coding method used here will largely be
based on work done by NTR through the COST 211ter project.
- A long term standard. This work will be made in co-operation
with MPEG4 and it is expected that totally new methods will
be developed for audio as well as video compression. A standard
is expected in 1998/99.
ISO/MPEG
The complete name of the group is ISO-IEC JTC1/SC29/
WG11. This means that WG11 is the working group where the
basic work is done. This working group is also called “Moving
Pictures Experts Group” (MPEG). As a working group it is
rather large – at the moment 200 – 250 participants to the meetings.
MPEG1 or ISO/IEC 11172 was completed in 1992. It is a standard
for “Coding of moving pictures and associated audio”. It
contains separate parts for video, audio and multiplex. The
bitrate is defined to be around 1.5 Mb/s. The resulting video
quality is approximately “VHS quality”. The audio part may
have full broadcast quality.
MPEG2 was started in order to develop a standard with full TV
quality. It is largely based on the same coding elements as
MPEG1 but extended to include the full TV format. NTR has
contributed actively to this standard by introducing new coding
elements particularly suited for the TV interlace format. Typical
bitrates for MPEG2 is in the range (2–10) Mb/s. However,
MPEG2 may also use HDTV formats and thereby give HDTV
quality with bitrates in the area (15–20) Mb/s. Thus the foreseen
work on HDTV in MPEG3 was never initiated. The status of the
standard now is Committee Draft – CD (November 93). After
balloting the final standard (IS) is expected to be ready late
1994. The name of the standard will then be: ISO/IEC 13818.
A new work item has been started recently. It is named MPEG4
and will deal with new compression methods aiming at bitrates
down to “a few tens of kbit/s” for live video. The current plan is
to have a standard by 1998/99.
ETSI
ETSI is not playing a significant role in the development of
video standards. ETSI NA5 has to some extent had the responsibility
of co-ordinating European inputs to other bodies. However,
this is becoming more difficult as the main participants
become manufacturing companies rather than telecom operators.
An important task of ETSI is to make ETSs based on standards
already developed in other bodies (see above).
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