Student films tend to be short, because students themselves are short on resources. They also tend to die, not so much from exposure as lack of exposure -- because they lack a mass audience.

Both constraints upon campus cinema will probably always be the case, but at least the four films that win the annual Student Film Awards get a national audience.If not a wide one. This is thanks to its sponsors, including the Academy of Motion Picture Arts and Sciences.

And if one can draw any conclusions from the 1977 winners about where our future commercial film-makers may be headed, based on the showing Wednesday evening at the Museum of History and Technology, the trend would seem to be in the direction toward wit and humor and away from angst and dirty words.

The winning documentary, a profile of a small-town Texas brewery, is a delight. "60 Minutes" should buy it and give television audiences a treat. They might have to do a little polishing, but as it is the film shows a flair and a humanity all too often lacking in television's most successful documentary program.

The subject is the Siner Brewery in Siner, Tex., a little community originally settled by Germans and now dwindling in its remote locations somewhere off the interstate between San Antonio and Houston. The film becomes, in fact, a profile of the people and history of a disarmingly distinctive small town.

The film starts with a charming sequence of stills during which the narrator traces the odyssey at the turn of the century of a German brewer named Spaetzl in his unsuccessful efforts to bring alcoholic pleasure to Egypt, western Canada and San Francisco. Finally, he hears about Siner, "where all the Germans like to drink beer, they just don't know how to make it."

There are moving moments, like the visit to Spaetzl's grave by a black man whom he adopted. And there is excellent footage showing the beer-making process.

The winning animated feature, by Paul Demeyer of the California Institute of the Arts, is a whimsical short about a madman scribbling on a long scroll that turns out to be a roll of toilet paper.

The $99[WORD ILLEGIBLE] experimental winner, "TRANC glance" by Philip Pura of Boston University, is a study of shifting patterns of black and white using a dance as the subject -- or, rather, the object.

The winner in drama, by Carol Dysinger of Bethesda, who attends New York University, is a portrait of a girl suffering through her 16th birthday in a broken home. Too many of the cliches of the 1960s are learned on and it is the only of the films filled with four-letter words and using a rock band in the background.

The awards are chosen by the Academy's members, as are the Oscars. The American Telephone and Telegraph Company and the American Association of State Colleges and Universities are cosponsors and finance the 25 prints that circulate free throughout the country.