New video technology may spell changes in movies, TV

Television viewers, already reeling in confusion over the wide range of new video technology, are now being asked to absorb still another major technical step forward - high-density TV or, as its developers refer to it, HDTV.

According to its NHK (the Japanese Broadcasting Corporation) and CBS sponsors , HDTV ''will prove to be to color TV what color TV was to black and white TV.''

Just what is HDTV?

It is a video system with a picture made up of 1,125 scanning lines, compared with the 525 scanning lines on most TV sets. This increased number of lines sharpens the picture and the color and changes the shape of the picture so it is narrower and wider, a la Cinemascope.

HDTV, which requires new cameras and, eventually, new TV sets (although HDTV pictures can be shown on normal sets without all the improvements visible), is already being hailed by some moviemakers as the electronic film of the future. It is less expensive than ''chemical'' (regular movie) film; can be transmitted by satellite; is easier to work with; and results in a picture almost as good as obtained with a 35-mm camera. Francis Ford Coppola is especially enthusiastic about HDTV and has already made some pilot shorts to demonstrate how effective it is.

NHK/VCBS executives estimate that new HDTV sets for consumers will cost 20 to 30 percent more than current color TV sets. HDTV is still in a pilot period, however, although it's marking time till the actual manufacturing of such sets. Obviously, the companies are awaiting acceptance of the system by TV and filmmakers as well as the general public.

It seems probable to marketing experts that the main use of HDTV programming may prove to be in movie theaters which will be able to handle the tapes, transmitted by satellite, more easily than their current handling of film. Thus, moviegoers of the future may be seeing basically large-screen TV.

NHK is currently involved in trying to convince TV and filmmakers that the system is worthwhile so that actual cameras and TV sets can move from pre-production prototype to the production line. Persuading filmmakers to go for it is the only the first problem.

Then there is the question of whether filmgoers will accept videotapes on large screens in theaters as they now accept 35-mm movies. Will they even be able to detect a difference?

Another important question: Does the average TV viewer care about technically better pictures and stereophonic sound, etc.?

In both cinema and TV use of HDTV, won't the bottom line still be the quality of the content of the show?