With global standards, high-definition TV could redefine television

``Can you ever make a picture as sharp in video as you can on 35-mm film?'' It's a question Arthur Kaiser likes to ask -- especially now that the answer is a resounding ``Yes.''

Visitors to the CBS Technology Center here, watching the astonishing crispness of an experimental videotape projected onto a 12-foot-wide screen, tend to agree.

If they need further convincing, the bearded, energetic engineer shows them into a darkened studio to compare two pictures of a Swiss mountain village -- one on a conventional TV screen, the other on an experimental set. On the ordinary set, the distant steeple clock is clearly visible, as is the fence-wire around the pasture in the foreground. On the other, however, you can all but read the numbers on the clock -- and you can see each barb on the wire.

This is high-definition television (HDTV), a development in video technology that promises to clean up television's notoriously fuzzy details -- and which, by reducing a need for close-up shots, could eventually change the way everything from football games to press conferences are televised.

But unless an international conference beginning Oct. 16 in Geneva can smooth out some longstanding technical differences among the world's various television systems, HDTV may have a tough time moving from the laboratory to the living room.

The conference has been scheduled by the CCIR (a French acronym for the International Radio Consultative Committee), which operates as part of the 157-member International Telecommunication Union (ITU) of the United Nations. This fall, after years of study, the 40-nation CCIR will try to agree to a worldwide standard for this next generation of video equipment.

The diplomatic challenge, not a new one, is akin to trying to establish a single worldwide gauge for railroad tracks or to deciding between right-hand and left-hand-drive automobiles: Every country wants to be flexible enough to accommodate new developments, yet each nation has its own traditions and preferences.

In negotiating the HDTV standard, ``we have to maintain a balance where the technology is allowed to breathe,'' says US Assistant Secretary of State Diana Dougan, who oversees international telecommunications issues for the State Department.

``This is the critical meeting,'' says Warren Richards of the US State Department Office of International Communications Policy. Calling the conference ``a unique window of opportunity to establish this worldwide standard,'' he adds, ``we think that we have a good chance.''

The goal is to reach agreement on a ``studio standard'' for HDTV production -- a move that, in future years, could gradually help eliminate a decades-old mismatch between the world's several different television systems.

At present, the United States, Canada, Japan, and much of South America use a system in which 525 horizontal lines of video information are blended by the eye into the picture on the screen. What is technically known as a ``field rate'' of 60 per second actually creates a new picture 30 times each second. The shape of the screen (the ``aspect ratio'') is a 4-by-3 rectangle.

This system, known as NTSC (for National Television System Committee), is different from the two systems widely used in Europe: PAL (for ``phase alternation line''), used in the United Kingdom and on most of the Continent; and SECAM (for syst`eme 'electronique couleur avec memoire ), used by the French and the Soviets. The European systems use 625 lines, with 50 fields per second and a slightly wider screen.

Observers note that each system has its advantages. Having more lines, Europeans tend to have more clearly detailed pictures. But with fewer new pictures created each second (25), they have more flicker -- a phenomenon noticeable to many American tourists.

For obvious reasons, no country is keen to abandon its own system and embrace another: National pride, not to mention the problems of rebuilding every transmitter and replacing every television set, presents daunting economic and political obstacles.

The current situation, however, has long vexed the industry. Programs made in Europe now have to be converted for broadcast over American television, and vice versa. With US revenues from the export of video programs reaching an estimated $1.3 billion this year, and with an expanding worldwide market for videocassettes, there are growing pressures for a uniform standard.

But ``if the wrong kind of system evolves,'' says Mr. Kaiser, ``or if no standard evolves, our concern is that this much improved television will be long delayed.'' Manufacturers, he adds, ``don't want to get going [and] make big investments unless there's some security for them that the systems are going to be used universally.''

The proposal under consideration by the CCIR (hammered out by an interim working party chaired by a Japanese, a German, and an American) does not attempt to define a standard for broadcast, but only for program production. Until HDTV sets become commonplace -- a development that may not happen before the turn of the century -- each country receiving an HDTV program will have to convert it to its own transmission broadcast standard.

And therein lies the bone of contention. Adjusting the aspect ratio, and converting the number of lines per frame, is relatively easy. Far more difficult, according to the experts, is converting between 50 and 60 fields per second. The CCIR proposal, calling for a standard of 1,125 lines, also calls for a field rate of 60 and a European-style wide screen (with an aspect ratio of 5.33 to 3) -- making conversions far simpler for the US and other NTSC nations than for the European countries.

The key to successful negotiations, in fact, may be a Japanese ``black box'' -- a computer-based converter developed by the Japanese national television service, NHK, that can transform HDTV into the conventional broadcast modes with hardly any loss of quality.

No one is playing down the immediate difficulties that the new standard would impose. If the working group's proposal is adopted, says Mr. Kaiser, it would mean that ``every program produced for whatever purpose, probably including spot news, would have to go through a conversion process to be broadcastable in [European] countries. In other words, there would be nothing that could escape going through the black box.'' So far, there are still some reservations about the proposal in Britain, Germany, Fran ce, and Italy.

But a new standard ``could be a real boon to the developing countries . . . and to other countries which want to disseminate and develop more programming about their own countries for broader than domestic distribution,'' says Ambassador Dougan. And it would help guarantee, says Mr. Loveridge, that ``American cultural influence continues to have a presence in the world.'' An occasional feature