BUDAPEST -- Choking with emotion, the elderly couple on the screen told how, as Jews, they had been deported to Nazi death camps during World War II and had been the only members of their families to survive.

Then came the real shock of the documentary film "In Keeping With the Law," which premiered here last week. Returning to Hungary after the war, the couple said, they had married and had a child, only to be arrested again and deported to a concentration camp, this time by Hungary's new communist authorities.

This time, the woman said, she had seen her child die of exposure and hunger.

"I told them it was better that they killed me than take me away again," she said as her husband looked on sadly. Later, she burst out: "The people who did this, their children should be killed as well."

The chilling account of how 100,000 Hungarians were forcibly relocated or deported to concentration camps in the early 1950s was the grimmest and most politically sensitive entry in Hungary's 20th National Film Festival last week. Never before had these excesses of the Stalinist era here been pubicly revealed in such depth, or communist authorities so harshly blamed for them.

Yet precisely for that reason, "In Keeping With the Law," a four-hour black-and-white documentary, emerged as the most honored film of this year's festival, easily besting the feature films. Its popularity among film professionals and an elite audience of Hungarian artists, journalists and intellectuals demonstrated how a drive for political openness and an accompanying trend toward antigovernment views have recently come to dominate the cultural world here.

"This was the year for glasnost in Hungarian film," said Miklos Vamos, a novelist and script writer, referring to Soviet leader Mikhail Gorbachev's policy of political openness. "We have entered into an era of journalism in film where the most important element is not art but the shout of protest."

In 1986 and 1987, film festivals here showcased modest comedies, dramas of daily life in Hungary or internationally oriented features like Istvan Szabo's "Mephisto" and "Colonel Redl." This year, however, feature film directors competed to show the most explicit dramatizations of formerly taboo subjects, while critical attention and popular applause focused on long, relentlessly critical documentaries about the crimes and failures of Hungarian socialism.

If one theme predominated, it was the bloody Hungarian revolt against communist rule in 1956, which until recently was a subject reserved for official accounts. One marathon feature film, "The Other Person," contained graphic reenactments of battles between sympathetically portrayed Hungarian freedom fighters and Soviet tanks and even slipped in a background broadcast of then-prime minister Imre Nagy's famous radio address announcing Hungary's withdrawal from the Warsaw Pact. The film, by director Ferenc Kosa, was awarded a special prize by the jury.

Another film, "Magyar Stories," was a documentary of the failed revolt in the small town of Dunapataj, while a third, "Cry and Cry Again" by Zoltan Kezdi Kovacs, wove a bitter attack on the repression by state security forces after 1956 into an account of the failed love affair of two people bereft by the loss of relatives during the uprising.

Not all the old taboos were broken. None of the films directly attacked the 31-year-old government of Janos Kadar, and even the portrayals of 1956 stopped short of full disclosure. Curiously, censors allowed the partial rebroadcast of Nagy's defiant radio speech but reportedly clipped an introductory line naming the popular prime minister, who was executed after the uprising and who is still so censured that Kadar reportedly refuses to allow the marking of his weed-covered grave.

Still, the openness of the films was remarkable for Hungary, which has long boasted the Eastern Bloc's most advanced economic liberalization but has been slower to expand political freedom. Clearly inspired by Gorbachev's glasnost policy, the relaxation of restrictions on expression visible here seems to go beyond that of the Soviet Union and rivals that of Poland, where a strong opposition has forced similar change.

"Nowadays whenever and wherever people gather they are talking politics, and the films are talking politics too," said Imre Poszgay, the leader of the Socialist Workers' Party's liberal wing, in an address at the festival. "Why should a forum like the film festival be an exception?"

While the documentary trend was applauded, some observers said the shift in tone had not kept pace with the mood of intellectuals, who are beginning to demand more political change from Kadar's party.

"The festival showed a kind of glasnost, but on the other hand we are not really delighted with it," said Matyas Vince, editor of Hungary's leading news magazine. "We've seen films here that half a year ago were almost unimaginable, and yet when you speak to people they say it's not enough, it's not relevant enough."

Other critics faulted the new films on artistic grounds.

"For my part, I'm fed up with the '50s and with all this openness if it has no real artistic attraction as well," said a liberal journalist. "These films are long and boring. The directors are so intent on breaking taboos that they forget there is a point after which it is unbearable for the audience."

Vamos predicted that "In Keeping With the Law," despite its shocking content, might not have much impact.

"In the end, no one is going to pay to sit in the theater for four hours," he said. "I wish the directors {Gyula amd Janos Gulyas} had had the courage to make a version of one hour and a half. As it is we have this glasnost but very few people will ever see it."