Charles Burnett looks slightly embarrassed when he is asked why it took a solid five years to film "Killer of Sheep," his blunt view of black working-class life in Los Angeles.

"Well," he begins, a deep breath blasting from his small frame. "I had committed myself to an actor, who was a friend, who was in jail, and the parole board kept turning him down." That was just problem one.

After three years of production delays, Burnett finally gave up on casting his jailed friend. But the problems of making an independent film in his childhood neighborhood of Watts, with his nonscreen-experienced friends, and without any money, didn't go away. Eventually, after a couple of years of weekend work and mediating the domestic disputes of the cast, Burnett completed "Killer" for less than $10,000. The 87-minute film won the Critics Prize at the 1981 Berlin Film Festival and the American Film Institute is presenting "Killer" as part of the New American Cinema showcase today, tomorrow and Thursday at the Inner Circle Theatre. Burnett, 37, who works full time at a Los Angeles talent agency, will discuss the film after the 7:40 p.m. screening today.

Burnett took his own notes about Watts to create "Killer," the story of a slaughterhouse worker who approaches his job and his family as a task. His emotions are played out against a sound track that includes Dinah Washington and Paul Robeson as the character cleans sheep carcasses, plays with and reprimands his children, loves and argues with his wife and turns down his friends' offer of a crime escapade. The film, which ends without any resolution, has a black-and-white documentary look. It offers an insider's journey into the streets, kitchens and apartment buildings of a hidden part of Los Angeles.

"Some of my friends who worked with me didn't understand how important the film was to me. There I was asking for their free time. And some of them were my friends but we had grown apart, so there was friction on the set," Burnett explains.

Burnett could utilize his soft, patient manner to solve the domestic disputes, but his filmmaker side, burning with statements yet unborn, was tested by the disregard for his concept. "They couldn't understand the continuity. They would tell me, 'I can't make it, can you use John in my place?' And then one character got thrown out of his house by his wife."

His friends, whose realism out-weighed any lack of acting experience, were not paid but they were fed. "And I had to buy good food or people got rebellious," says Burnett, with a quiet nonchalance. Dressed in casual slacks and sweater, Burnett's problems didn't appear to add any years to his lean, serious face. An earlier unfinished effort of his, "Several Friends," has yet to be seen publicly because of fights on the sets.

But Burnett was spurred forward by his own sense of mission, translating the Watts environment, those friends and himself into full-dimensional screen entities. That's what made him switch in 1965 from an electronics curriculum at the Los Angeles Community College to film-making at UCLA. "I was always interested in arts. But my community wasn't interested in arts. You had to do something concrete, you had to make a living," said Burnett.

His mother works as a nurses' aide, his father is a military career man, who didn't stay with the family, and most of Burnett's friends got into trouble early. "All the kids I knew were in jail. I just happened to live in a good spot . . .Also, I had a speech impediment, I was teased about my stuttering and I was an outcast. That lack of involvement set a pattern of independence for me."

"Killer," his thesis project at UCLA, was inspired, he says, by other young filmmakers' insensitivity. The fact that the social realism films were by middle-class students who had nothing to do with workers made him angry enough to feel he should correct that fraud.

"Killer" is a quiet film with frank visuals but explained motivations. Some might feel the women are set up as oppressors; some might feel acceptance, rather than rebellion, is the code of this life. Says Burnett, who financed the film and another award winner, "The Horse," with a Louis B. Mayer Award at UCLA and his own money, "Some have criticized it for being dead-end and defeatist but this [the central character] is a family man and he continues in that context, he doesn't give up."