Glossary: V

Video coding

So far all HDTV television systems around the world, including the DVB system, are based on the MPEG-2 video compression scheme and use as the basis an MPEG-2 Systems defined Transport Layer. This leads to a very high commonality of all HDTV systems in use around the world.

DVB is now underway to include more advanced audio/video compression tools such as e.g. H.264 (MPEG-4 AVC) and later maybe SMPTE VC-1 into its standards. DVB will provide the necessary tools for efficiently broadcasting HDTV in the coming years.

Even if new coding tools are becoming available, Set-Top-Boxes for the new HD standards will be backwards compatible with MPEG-2 MP@HL transmissions and current standard definition broadcasts in MPEG-2.


Video compression

The data reduction and compression of analogue TV signals into a digital stream. It is used by ASTRA to broadcast several channels through a single transponder.

Video on demand

A subscription service where users order films or TV programmes on an individual basis to be viewed at a time that suits them.


Very small aperture satellite terminal

A small two-way satellite ground station with dish antenna normally under 2.4 metres in size. They access satellites in geosynchronous orbit and relay signals from small remote ground stations to other terminals or master earth station or hubs. They are also used for mobile satellite communications systems.