A Coca-Cola commercial interrupting the film? ''So what?'' an American would say. But such ads on the new cable television network in this German industrial town have set off a violent debate throughout Europe.
Today, Europe's public stations strictly limit commercial breaks. In France, no program can be interrupted. In Germany, only 20 minutes daily of commercials are allowed, and none after 7 p.m. Viewers pay a license fee to support the stations.
Cable television will change all this.
Cable hookups are expensive, up to $2,000 a household for France's futuristic fiber-optics network, and most of Europe's financially strapped governments cannot afford such sums. So they are wooing private investment to help meet the costs.
This private investment means advertising - and nightmares for leftist politicians. Big business will take over, they charge, giving it a new, dangerous power.
''All the right-wing newspaper publishers are moving into cable,'' argues Peter Paterno of the German Social Democratic Party. ''Soon they are going to control all the broadcasting news outlets as well as all the written press in the country.''
Public broadcasters are also worried. They fear that cable will take away their best programs, undermining popular support for their license fees. For example, Michael Smithson of British Broadcasting Corporation warns that the big multinational cable operators will be able to outbid public organizations for films and sports events.
''You'll have to pay to watch Wimbledon on television,'' he says. ''That would be a tragedy.''
And who might buy up Wimbledon? And flood Europe with trashy, cheap programming? The imperialistic American giant, of course.
The new private cable operators need program after program to fill their multiple channels, and the only suppliers with enough material at reasonable prices are in the United States.
''Presently, British television limits American imports to 14 percent of all programs,'' explains Nick Melish of Entertainment Television, a British cable company. The rest of Europe has similar restrictions, some formal, some informal. ''But if those limits are maintained for cable here, there will be no cable. Our programming will have to be at least half American, maybe more.''
At best, this prospect fills Europeans with foreboding. ''It won't improve our television to just have more and more old films and American sitcoms,'' says German national television's FriedrichBlumenbroch.
At worst, it fires fright. Former German Chancellor Helmut Schmidt once said cable television would destroy German family life. French critics helped derail Luxembourg's plans for a private satellite channel by dubbing it the ''Coca-Cola station.'' The BBC's Smithson concludes, ''We don't want to become like Canada.''
European fears are not only cultural, but economic. choThe governments pushing cable see it as a necessary expense to provide the infrastructure for the information age and to foster an economic bonanza, providing work for such disparate groups as construction workers and artists, aging steel plants, and modern high-technology corporations.
But critics question the investment. They say new cable materials and satellites soon may make the present cable systems obsolete. Moreover, will Europeans want to pay enough for extra television to support cable?
The signs are unclear.end cho In Britain, some studies show that only about one-quarter of the population is ready to pay $7.50 a month for cable - and that is only half the amount the most basic service is expected to cost. In France, the planned cable channel, Canal Plus, is bogged down with financing problems because it has succeeded in getting commitments from only about 60 percent of the 500,000 viewers necessary for the project to break even. In Germany, there is somewhat more interest: Surveys show that nearly half the population wants cable.
''But even that isn't enough,'' charges Mr. Paterno of the German Social Democratic Party. ''The government is going to lose a bundle on cable cho- and with satellites coming, the investment isn't going to make us more competitive in telecommunicationsend cho.''
None of this opposition, however, has ended government plans for huge cable investments. By the end of the decade Paris aims to spend about $800 million to wire about half the country's homes. English and German projects are just as ambitious - and expensive.
Once the new channels are operating, cable boosters are confident the public will tune in. choDespite the polls, there are some good reasons for this positive thinking.
Europeans are growing impatient with their present public television offerings. Traditionally, only about two hours of TV are watched daily around the Continent, just over one-quarter of the American average. Partly this was due to limited broadcasting hours; most countries prohibit morning television.
Recently, however, audiences throughout the Continent have been dropping even lower. In France, for example, there has been a 10 percent decline during the past two years. Meanwhile, Europeans have rushed off to the movies or the video cassette recorder shops.
The problem, according to cable promoters, is that state television is burdened with inflated bureaucracies and spiraling administrative costs. Cull programming is the result, and ironically, the public broadcasters have been forced to import ''Dallas'' and ''Dynasty'' to win back viewers bored with cultural and educational prime-time programming.
''Until there is cable, we're going to have to suffer with programs on Japanese culture,'' moans Walter Bruckman of the governing German Christian Democratic Union.
Even the famed BBC comes in for criticism. ''It's a huge octopus,'' complains David Davis of the British Conservative Party. A little competition would only improve it.''
Here in Ludwigshafen, chothis elementary rule seems to be working forend cho Germany's first cable network. Director Claus Detjen reports that nearly 5,000 customers have paid the hefty 600 mark ($230) fee for the new cable service since its inception Jan. 1. By the end of the year, he expects to wire 15,000 of the city's 40,000 homes, and within five years 90 percent of the homes.
Municipal news on a new local-affairs channel is a popular offering, Mr. Detjen says. But cable's big attraction seems to be the enormous amount - nearly 50 percent of the total - of American programming on the network's 10 other new stations.
''Hollywood films and shows like 'Love Boat' are very well watched,'' Detjen reports. ''A recent broadcast of the Super Bowl did less well. Just give it some time, though. Even American football will find an audience.''