Television's wide boys may have to wait: British opposition may sink a European strategy for high-definition TV, leaving viewers in the dark, says Steve Homer

THE European summit in Edinburgh this week could have a bigger effect on the television we will be watching next century than the Government's Green Paper on the future of the BBC.

Failure of the summit to reach agreement on refinancing the EC would sound the death-knell of Europe's strategy for High Definition Television, which promises a picture one-third wider than that of today's sets and almost four times as clear, with cinema-quality sound.

At present, the HDTV strategy is in tatters. At the Council of Ministers meeting last month, Britain, supported by the Danes and some of the poorer EC countries, blocked a move to spend 850m ecus ( pounds 685m) on preparations for introducing the European HDTV standard, HD-MAC, and conventional-quality wide-screen television. Britain thinks there is no demand for HDTV, and that investment now would simply distort any future market. Holland and France, however, are keen to help their electronic companies, Philips and Thomson, to recoup part of the huge sums they have invested in HDTV research.

For many in the broadcasting industry, this impasse will not be such bad news: they consider that the European system is beginning to look so out of date that it should be abandoned. Their fears are based on the rapid development of digital television, and the unexpected benefits it offers. This system seems to be gaining so many American supporters that the United States looks certain to select it for introduction in 1995.

In the current analogue systems, the television picture is divided into lines (625 in Europe and 525 in the US and Japan), each of which is transmitted as a wave carrying information about brightness and colour. In digital systems, the lines are divided into individual picture elements, called pixels, each of which is assigned a colour and brightness value. In its raw state, the digital picture contains more information, and so requires wider channels for transmission. However, researchers have developed tricks to reduce the amount of information that needs to be sent.

The colour and brightness of pixels is not random, so by coding blocks rather than individual pixels, enormous amounts of data can be saved. For example, all the pixels on an area of skin will be closely related in terms of colour and brightness, and patches of blue sky will be made of pixels of closely related colours. These can, therefore, be described simply in mathematical formulas.

The other way to reduce the data that have to be sent is to transmit only the information that changes from frame to frame.

As the technology has developed, so has the ability to squeeze signals, without significantly reducing picture quality. A satellite channel, which today can be used for one standard television signal, could tomorrow be used for one, or possibly two, HDTV channels, or more than 10 standard definition stations.

Although digital television still requires a great deal of research in some areas, it may move into commercial operation, through cable television companies and programme providers, before the end of this month. These companies use satellites to deliver high-quality television signals. The encoders required to convert the signal from analogue to digital cost well over dollars 500,000 each, but such an outlay is viable because only one satellite channel, instead of two or four, now needs to be leased.

Cheap domestic digital television is not far away. At present, most urban areas in the US have access to sophisticated cable systems, but to cover the rural market, the aerospace and engineering company, Hughes, has developed DirectTV to beam 150 channels into individual homes, through small antennas. The system will be launched in mid-1994, and an antenna will cost less than dollars 700 ( pounds 450).

But what will people watch on this 150- channel digital television? There will be some niche channels - educational, sport, adult entertainment and the like - but most capacity will be devoted to pay-per- view (PPV) films and special events.

American cable operators have discovered that the best way to sell popular movies is to have them starting every 15 minutes or so on different channels; that way viewers are never more than 15 minutes from the start of a movie they may prefer to watch and are willing to pay to have the signal

unscrambled.

This inevitably gobbles up channel capacity, so it is not surprising that cable television is one of the businesses pressing hardest for digital compression.

Since satellite companies will soon be able to supply as many channels as a current cable system, the cable operators are running hard to stay ahead. Quantum, an experimental system in New York, is already supplying up to 150 channels to thousands of homes in the Bronx, even without digital compression.

The main proponents of Europe's HD- MAC system, Philips and Thomson, are heavily involved in American digital HDTV consortia; News International and Canal Plus, the French independent broadcaster, agreed last month to join forces on digital research; and SES, the company that owns the Astra satellite system used by BSkyB, has said it aims to be carrying digital test transmissions by 1995.

Philips has said publicly that if the 850m ecu package is not agreed, it will virtually abandon HD-MAC work. The stark fact remains that while some demand for wide- screen television does appear to exist, an HDTV standard has yet to emerge, because a combination of the system with today's television technology has little support. When large, affordable, hang-on-the-wall television sets become available, an HDTV market will follow, but that is unlikely before the end of the century.

Many Department of Trade and Industry officials believe that HD-MAC should be allowed to die a graceful death, a wish that may well be granted when on 1 January the presidency of the Council of Ministers passes to the Danes, who are almost as strongly opposed as the British to funding it. HD-MAC is about to die.

(Photograph omitted)