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Overview
This website describes the moving picture compression system developed
by MPEG - the "Moving Picture Expert Group".
This group was set up in 1988 to establish standards for the coding of
moving pictures and associated audio for applications such as digital
storage media, distribution and communication.
As with JPEG compression for still pictures, the work is carried out
under the auspices of three major standards organisations - ISO
(International Standards Organisation), CCITT (International Telegraph
and Telephone Consultative Committee, now ITU-T), and IEC (International
Electrochemical Commission).
The MPEG standard is, rather like JPEG, a set of tools that allow a
system that has a need to compress moving images to be configured. The
range of potential applications for MPEG is very wide, and includes :
· Transmission via satellite, terrestrial, and cable broadcast systems
· Videoconferencing
· Interactive storage media
· Networked database services (video servers)
· Serial storage media (digital VTR etc.)
· Electronic news gathering, including satellite news gathering
· Remote video surveillance
MPEG encompasses a wide range of qualities and data transmission rates.
For convenience of applications and data rates the standard has been
divided into-3--areas MPEG-1, MPEG2, and MPEG-4.
MPEG-1 is intended for use on a storage medium that has a data
transfer rate of up to 1.5 Mbits per second.
MPEG-2 extends that work to broadcast picture resolutions and
quality.
MPEG-3 was intended to cover high definition television systems,
but the work of MPEG-2 was so successful that MPEG-3 was incorporated
within MPEG-2.
MPEG 4 is intended for very low data rates from mobile video
phones.
The MPEG standards define the data stream that must be processed
by a decoder, they do not define the structure of the coder. The only
requirement placed on the coder is to produce a valid data stream. This
allows coders that are produced in the future to make better use of the
decoder features that are already present.
It is assumed that the reader is already familiar with the principles of
discrete cosine transforms and data re-quantisation.
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