62 What is MPEG-2?
Description
This article is from the MPEG FAQ, by Frank Gadegast phade@cs.tu-berlin.de with numerous contributions by others.
62 What is MPEG-2?
MPEG-2 FAQ
version 3.7 (May 11, 1995)
by Chad Fogg (cfogg@chromatic.com)
The MPEG (Moving Pictures Experts Group) committee began its life in
late 1988 by the hand of Leonardo Chairiglione and Hiroshi Yasuda with
the immediate goal of standardizing video and audio for compact discs.
Over the next few years, participation amassed from international
technical experts in the areas of Video, Audio, and Systems, reaching
over 200 participants by 1992.
By the end of the third year (1990), a syntax emerged, which when
applied to code SIF video and compact disc audio samples rates at a
combined coded bitrate of 1.5 Mbit/sec, approximated the perceptual
quality of consumer video tape (VHS). After demonstrations proved that
the syntax was generic enough to be applied to bit rates and sample
rates far higher than the original primary target application, a second
phase (MPEG-2) was initiated within the committee to define a syntax
for efficient representation of broadcast video. Efficient
representation of interlaced (broadcast) video signals was more
challenging than the progressive (non-interlaced) signals coded by
MPEG-1. Similarly, MPEG-1 audio was capable of only directly
representing two channels of sound. MPEG-2 would introduce a scheme to
decorrelate mutlichannel discrete surround sound audio.
Need for a third phase (MPEG-3) was anticipated in 1991 for High
Definition Television, although it was later discovered by late 1992
and 1993 that the MPEG-2 syntax simply scaled with the bit rate,
obviating the third phase. MPEG-4 was launched in late 1992 to explore
the requirements of a more diverse set of applications, while finding a
more efficient means of coding low bit rate/low sample rate video and
audio signals.
Today, MPEG (video and systems) is exclusive syntax of the United
States Grand Alliance HDTV specification, the European Digital Video
Broadcasting Group, and the high density compact disc (lead by rivals
Sony/Philips and Toshiba).
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