CARLOS DIEGUES became a filmmaker to reckon with during the 1960s, when he helped establish Brazil's influential cinema novo movement - a new wave of film activity dedicated to confonting Brazilian social and political problems. Although that movement is no longer an active force, Diegues has become one of Latin America's most internationally acclaimed directors, with such socially conscious movies as ``Bye Bye Brazil'' and ``Quilombo,'' both of which have been critical successes in the United States. His latest film is a drama called ``Subway to the Stars,'' set in Rio de Janeiro. The main character is a young jazz musician named Vinicius, whose girlfriend mysteriously vanishes one night. Searching for her, Vinicius travels into the poorest and most dangerous parts of his city. His only helpers are a friend who'd rather go and live in New York, and a tough policeman who remembers Brazil's former military government with nostalgia.
``Subway to the Stars'' deals with harsh and unpleasant subject matter. But its hero is a musician - based on the mythical character of Orpheus - and the tone of the movie is determined in large part by the lively music on its sound track. Diegues says his film is concerned with art, poetry, and love - not as entertainments to make us forget about world problems, but as tools for helping us understand our world better.
``I don't think films can change reality,'' the director told me during a recent New York visit. ``It's impossible. A film is not a machine gun! But I think we can change the conscience of the audience. In other words, we can change the way people see reality and understand reality.''
In making ``Subway to the Stars,'' Diegues wanted to give his audience an unusually realistic view of Rio de Janeiro. This explains why the film so insistently explores the slums and the unpleasant underside of the city.
``We have the habit of seeing Rio de Janeiro on the screen like paradise,'' the filmmaker says. ``It's [depicted] like a tropical city and beach where everybody's happy.... I think in this film we see the real Rio de Janeiro. I shot it where maybe 70 percent of Rio's population lives really.'' Diegues hopes this will impress moviegoers with everyday Rio de Janeiro hardships - which are generally ignored, he says, by Brazilians and others who are ``alienated'' from unpleasant facts that don't affect them directly.
This does not mean Diegues wants his movies to preach or talk down to audiences. He knows that an effective movie is a popular movie that lots of people want to go and see.
``I know that the first social role of a film is to be entertaining,'' he says. ``That's for sure. But after that, if you can at the same time keep a moral commitment with people who are seeing your film, this is very important.''
``I was a kid when I started loving movies,'' he says with a happy smile. ``Everything I know in my life I learned from movies, and mostly American movies. The American cinema made up our minds - not only mine, but my whole generation. We have been seeing American movies for so long that we are impregnated with them.
``I have my own idols in the American cinema,'' he adds, ``like King Vidor and John Ford and Orson Welles. ... I mean the classics. Everything I know, I know from American movies first. Afterwards I went to books and to school.''
Even today, Diegues says, about 65 percent of films shown in Brazil were made in the United States. Only about 25 or 30 percent come from Brazil itself.
``In every country in the world,'' he explains, ``there are two national cinemas: the local cinema and the American cinema. You take France, nowadays. Fifty percent of the French market is being occupied by American movies. And it's like that everywhere in the world. The American cinema is very strong. It's not only a matter of economics. People like those films!
``I'm not very familiar with financial problems in the world,'' Diegues continues, ``but they say that Japan is taking over the whole economic world and becoming the first financial power in the world. But Japan will never export its culture. Japan will always consume the American culture.... There is something very deep and very strong in the American cinema.''
Even though American films continue to dominate the world movie scene, Diegues feels the arts are entering a new period and that national art movements, in a traditional sense, may be disappearing.
``A lot of things are changing in the world these days,'' he opines, ``in a cultural sense. ... I think we are living in a world that's becoming a planetarian culture. For instance, African music is influencing American music, which influences Brazilian music.
``Somehow those things become finally not national but very international. Maybe we are in the eve of a new international culture. And in the cinema, of course, American cinema will be the leader.''
Diegues doesn't think about such large issues when he's actually at work on one of his movies. He's a practical filmmaker who knows that each new project needs a fresh approach.
``The main thing in my thoughts when I'm making a film,'' he reveals, ``is to represent the state of mind - the spirit - of my time and the society where I'm living. That's the way I go into filmmaking.''
Diegues does acknowledge, however, that certain key ideas run through all his films, tying them together. These ideas grow from his thoughts about the society he reflects, and studies, in his work.
``I think that every human utopia has died, has been destroyed,'' he says, summing up these ideas. ``We are living in very hard days, and people are looking for some sort of new way of living together.
``I believe that solidarity - really caring for others - will be very important in this eve of a third millennium. I'm going to make my films on this subject. `Subway to the Stars' is a film about friendship, about solidarity. That what it's all about.''