Five minutes into China's smash-hit play, "Newsboys," the chatter from the packed Saturday night audience finally quieted enough so that the actors could be heard. When the curtain came down on the last act, everyone rose quickly and headed for the exits. There was barely a ripple of applause.

The chinese of this southern regional capital were demonstrating another side of China's new cultural freedom - the right to be different.

In a remarkable blossoming of the arts across the People's Republic, new and old plays, movies, operas and ballets are being staged in hundreds of theaters where the doors were often shut in the past. But despite the enthusiasm and variety on stage, China's millions of theatergoers are often responding with little more than a rattle of empty pop bottles, a buzz of private chat and a shuffle of feet.

The Chinese performing arts ensemble now visiting Washington must find the long and loud applause of their American audiences a strange contrast to the lukewarm response they often get from fans back home. One Peking concertgoer voiced his annoyance at his countrymen's theater manners in a letter recently published in the official People's Daily: "I felt ashamed because the decorum in the concert hall was unthinkably bad and the influence on the evening extremely unpleasant."

At six different plays, movies and operas attended during a 10-day trip to three southern Chinese cities, local audiences invariably arrived late, talked loudly and applauded little, even at live performances. These are said to be old Chinese habits, and Chinese audiences seem secure enough in the new period of "one hundred flowers blooming" in the arts to be casual and nonchalant, even when upbraided in the official party newspaper. What the cultural reawakening really offers many of them is more chances to go out with friends at night and chat in an air-conditioned theater, and that is at least as important to many poorly housed Chinese as the chance to see something new on stage.

When a Chinese audience sees something it likes, and there is much more of that now than there used to be, they respond with warmth and excitement, though not much hand-clapping. A crowd packed into a sweltering unair-conditioned movie theater in Canton laughed and cheered at a 1957 romantic operetta, full of boy-meets-girl winks and blushes. There was hearty, if brief, applause for a local-girl-made-good who was announced as the star of an opera in Kweilin. The audience for the "Newsboys" here in Nanning hushed to a whisper when the actor playing the revered late Premier Chou En-Lai made his torchlight entrance into the stage.

For 10 years, until about a year ago, plays and operas had to pass such strict tests of seriousness and political usefulness that few were produced and many theaters were closed much of the time. When tickets were available, they were often doled out by offices and factories as rewards for good behavior. Few people were allowed simply to go to a box office and buy a ticket.

Last year, after the dust had settled from the 1976 death of Mao Tse-tung and the purge of his dogmatic "Gang of Four" followers, dozens of movies and plays that had been banned for bad politics or lack of politics were released or restaged. Box offices started selling tickets to all comers. The liberal-minded diplomat Huang Chen, whose easygoing manner had graced the Washington cocktail circuit while he was China's envoy to the United States, came back to Peking to serve as culture minister.

"The present shortage of all genres of literature and art caused by the sabotage of the Gang of Four should be rapidly overcome," said new Party Chairman Hua Kuo-feng. "The repertoires of the performing arts ahould be enlarged to enrich the people's cultural life.

Foreigners living in or visiting China probably welcome the change even more enthusiatically than the Chinese. Anyone who had to sit through the endless clenched-fist poses and olive-drab costume of the "East is Red" ballet welcomes with relief revived productions like the dance-drama "Small Dagger Society". This restored production, although still taking a revolutionary theme, provides catchy tunes, girls in filmy costumes and even some Kung-fu fighting.

In Peking, where many foreigners often attend theaters, the Chinese audiences occasionally pick up Western habit of demonstrating approval. In their debut in Peking, "Newsboys" actors had to answer several curtain calls.

But without many foreigners around, the Chinese audiences generally resume old habits. "The impression I have is that the Chinese feel they have paid their compliment to the performers by buying a ticket, and there's not much to do anything else," said one longtime British resident of Peking.

Chinese living in apartments here and in other cities are often allowed no more than one room for every two members of the family. Production of television sets is slow and other opportunities for evening recreation are few and far between. So people here have welcomed the reopening of the theaters as a way to get out of the house, and they seem to go back again and again no matter what is playing.

Asked about the tepid reaction to "Newsboys" here, tourist guides Yin Chien-chou said, "Some of them may have seem the play before, so they are not so interested."

Such excuses did not mollify an avid Peking theater goer named Hsai Li, whose angry letter to the editor appeared in the official People's Daily a few days after the Nanning audience chatted through "Newsboys".

"Unfortunately, this kind of Phenomenon occurs very often," he wrote, referring to incidents he had encountered in the national capital, 1,500 miles north of this much more provincial city. When Hsia attended a concert at the capital gymnasium, "Those who came late and those who left early were like a river winding here and there. Coughing, spitting, talking and laughing could be distinctly heard from the audience. Empty bottles rattled here and there . . . Our wise leader Chairman Hua calls on us to raise the scientific and cultural level of our Chinese nation. To me, this should include forming more "civilized" habits . . . "

At the Kwangsi Arts Institute here, young people studying for future concerts simply delight in the chance to perform and worry littly about audiences, according to dean of study Ho Wei-chi. Would-be dancers aged 14 and 15 demonstrated a repertoire of backflips and double tucks. Art teachers looking strangely Bohemian with recently grown moustaches - a rare sight in China - watched students doing still lifes and old-fashioned, prerevolutionay calligraphy. A 17-year-old pianist ripped through a short piece of Beethoven. She had heard it performed only once, on a Russian phonograph record. But a piece of Chinese music, from the "Small Dagger Society," she performed with accent and feeling.

"Last year we had 18,000 apply here," said Ho, with a sad look clouding his usually sunny demeanor. "We could only let in 220."

The multi-faceted concerns of the arts institute seemed to reflect the eclectic style of many Chinese stage performances, like what the arts ensemble has presented to Washington audiences. An evening's performance by a Hainan Island troupe in Canton seemed almost a return to vaudeville, with accordian solos, operative arias and a native dance with young girls in red and blue caps, white with blue polka-dot tunics, blue kilts with white cowboy fringe, red patterned leggings and sandals.

When the audiences for such a production are fresh, they seem delighted and attentive, such as the night a local troupe put on their new comedy, "The Sweet Life." Many people came late, chatted and left early, but they also laughed often and loud at the antics on stage. It was the closest this strait-laced society could come to a bedroom farce. The play's heroine was a mother of five daughters, fighting the official birth control policy in her eagerness to produce at least one son. In the end, she lets her daughter marry a nice young technician and accepts him as her long-desired son, but not before many misunderstandings intrude.

"I Love Lucy" has never been shown on Chinese television, but the "Sweet Life" attempted some of the merry mix-up effects. At one point the weary husband of the heroine rushes to the hospital at the time for the birth of his fifth child nears, and takes his office assistant with him. The younger man uses the hospital telephone to arrange a study date with a young woman he has just met.

"Yes, I think I can meet you," she says, quite pleased. A nurse runs shouting past the hospital telephone. "Where are you?" the girl asks, puzzled.

"Oh, just here in the maternity ward," the young man answers.

"What?"

"Well, the baby's about to be born."

"Baby?"

The nurse shouts something at him. "Oh, I have to run, the time has come. Hello? Hello? Hello?"