A white woman watching the film suddenly stormed out of the room in a fury and angrily ripped down the posters billing the movie.

In another city, a black projectionist showing the same film had to be protected by police from a group of black men wielding daggers and an ax. They were angry because they had been told there was no more room for them in the already jammed makeshift theatre.

In the audience of that same theatre, a middle-aged black woman, recently released after five months in detention without being charged, was weeping openly.

The movie was "Roots," and it has caused a sensation in this country where black emancipation is yet to be realized and the fabric of black-white relations is tautly stretched.

The U.S. International Communications Agency (formerly U.S. Information Agency) has been showing Alex Haley's epic of multiracial audiences in four of South Africa's major cities as part of its worldwide offering of the popular movie. In a fifth city, the black township of Soweto, the audiences were all black.

At every site people had to be turned away. In the coastal town of Durban 1,400 people sat in three rooms to watch staggered three-hour showings on three consecutive nights. In Cape Town, some 300 people, many sitting on the floor, saw the lenghty film in two sittings of six hours each.

A request to be shown the story of Kunta Kinte and his descendants even came from the Kwazulu Legislative Assembly, the local governing body of South Africa's 5-million Zulus.

And in Johannesburg, "Roots" sprouted some amusing stories. It was being said that the government-run South Africa Broadcasting Corporation was going to air the film, but run it backwards to give it a "happy ending."

The South African authorities did not officially convey displeasure at the showing of the realistic film, but on the one occasion when it was shown off U.S. property, local police appeared at the site - at the University of Natal - and objected to the fact that it had not been submitted for approval to the government's censorship board. The University of Natal was asked to pay a nominal fine which it refused on principle to do the final installment of that showing was never run.

Although the members of South Africa's all-white Parliament were invited to see the movie, only the leader of the opposition, Colin Eglin, toop up the offer. One legislator replied that although he had read the book, he would not go to see the movie unless the U.S. government was also prepared to show films "about all the Harlems that exist in the United States."

Many of the young black people who watched Kunta Kinte's trials said it was a lesson in perseverance.

"We got a lot of encouragement from it," said one young Soweto resident. "Kunta Kinte was striving to get his freedom and for us that meant that in spite of everything we don't have to give up."

"'Roots' goes to show how the Americans have progressed until today when they have Andy Young as ambassador; it gives us hope," said another.

One person who was moved, especially when Cicely Tyson learns her son Kunta had been kidnaped, was Ellen Khuzwayo, 51. Known as the "grand old lady of Soweto," this social worker was among the black leaders arrested by police last Oct. 19. She was released without being charged in April.

"It leaves you dazed," she said of "Roots." I was depressed after I saw it."

"I naturally came back to our own situation in this country. People keep on saying we are freer [than those slaves] but I see us in exactly the same situation. The white community here lives in a democratic atmosphere but the black community lives in another world and in complete oppression."

The black-oriented Johannesburg Post ran an unusual commentary on the black family epic entitled, "'Roots' Wasn't Funny - But we laughed."

The black writer, Ernest Shuenynane, wrote, "Whenever lines that degraded blacks were spoken, whenever action that displayed naked cruelity towards blacks was seen, the black audience reacted with laughter.

"But the laughter that was uttered was not similar to that I usually hear at parties, night clubs, shows and funcions . . . It was empty, cold and creepy."

Zuko Tofile, a black who showed the film to Soweto audiences confirmed Shuenynane's observation. Explaining this reaction of blacks, Tofile said, "It was not really a laughter of joy. It was caustic. It's like when I don't want to cry openly. I want to show that I'm strong and I don't want to show my enemy that I'm hurt.

According to American officials, many of the whites who viewed the film were also deeply affected.

"We must get the Nats," or members of the ruling National Party, "to see this before they kill us all," one perturbed white man was overheared to say.

The most explosive reaction occured in Pretoria, the adminstrative capital and a citadel of conservative feeling. During the fifth episode at the point when Missy Anne refused to acknowledge Kizzy despitte the fact that they grew up together a white woman suddenly got up and shouted, "What are they trying to do?" She ran outside and tore down the posters advertising "Roots."

The next day, however, she telephoned to apologize, offering to pay for the damaged posters. She said she had been incensed by the thought that the film was only being shown in South Africa because of American disapproval of this country's racial policies. The U.S. official explained the film was being shown worldwide.

Before the film made the rounds here, the hard-cover edition of Haley's book had sold briskly in South African bookstores and a handwritten sign in a shop window yesterday announced, "At last, 'Roots' in paperback." Although the government's censorship board has banned works portraying black-white relationships in milder terms than "Roots," so far it has not acted against the American work.

A traveler in other countries in southern Afica sees evidence of "Roots" popularity. In the former German colony of Southwest Africa (Namibia) the German edition is prominently displayed in a shop window. And in the Salisbury headquarters of the black Rhodesian political party, the United African National Council, a huge color picture of Kunta Kinte in chains hangs on the wallbehind the receptionist.

Although the unfolding drama in southern Africa between black and white is providing plenty of material for the writing of a South African "Roots,"the time does not yet seem ripe for it to appear. As one "colored" (mixed race) writer who had seen the film asked, "if there is going to be a local version finally, who will dare to write it?"