When the Baltimore Film Festival began 21 years ago, th program was largely experimental, a selection of films of all lengths, most of them by American film students.
Later, many of the films were foreign, something that is true of the 22nd annual festival. It will, however, begin with a program that is, in a way, a salute to the early festivals. The opening program, beginning tonight at 7:30 at the Baltimore Museum of Art, is a group of films shown under the collective title of ''Director's Showcase.''
All are less than 30 minutes. Among them are ''A Little Vicious,'' a reference to a pit bull, ''Only Natural,'' whose subject is described as a ''no-no,'' ''Lunch Date,'' which was nominated for a film-short Oscar this year, ''Touch My Lips,'' about an Elvis impersonator, and ''In Your Own Sweet Way,'' done by Pat Kahoe of Baltimore. Kahoe's film is only 22 minutes but says all that needs to be said, with poignancy, about a 1953 jazz musician who is killing himself and his career with drugs.
The festival will continue on Friday at 7:30 p.m. with ''All the Vermeers in New York'' (1990), an American film done by Jon Jost. In it, a French actress living in New York meets a Wall Street trader at an exhibition.
At 9:15 the same evening, the film will be ''American Dream,'' a 1990 American film directed by Barbara Kopple. The Hormel strike is the topic. This one won the Academy Award for Best Documentary.
On Saturday at 7:30 p.m., the only film will be ''Life and Nothing But''(France, 1989), a drama about two women who search for their men who are thought to have died in World War I.
This screening will be followed by a champagne reception at 10 p.m.
Sunday will bring a tribute to character actor Vincent Gardenia, who is expected to attend ceremonies that will include clips from Gardenia's works on television and the big screen. Topping all this will be ''Age Old Friends,'' a drama Gardenia did for HBO with Hume Cronyn.
The festival, which will be held Thursdays through Sundays through April, resumes on April 11 at 7:30 p.m. with ''The Arsonists'' (Russian, 1988), about life in a school for troubled young women. At 9:45, the film will be ''Driving Me Crazy'' (British, 1990), a documentary about the recording of a black musical revue.
The remainder of the schedule:
Friday, April 12:
''Lonely in America'' (USA, 1990). A comedy about an Indian who moves to the United States where he hopes to become part of the melting pot. 7:30 p.m.
''Blackeyes'' (England, 1990). The professional life of a model and the people who use her. 9:15 p.m.
Saturday, April 13:
''Robot Carnival'' (Japan, 1987). Eight animation artists do pieces on robots. 7:30 p.m.
''Bakayaro! I'm Plenty Mad'' (Japan, 1990). Four episodes on life and stress in Japan. 9:15 p.m.
Sunday, April 14:
''Black Rain'' (Japan, 1989). An atomic bomb is dropped on Hiroshima, and those who don't die instantly face lingering death. (Not the Michael Douglas film of the same name.) 7 p.m.
Thursday, April 18:
''Tong Tana'' (Sweden, 1990). The destruction of the Malayan rain forest and the effect this has on the Penan Indians. 7:30 p.m.
''Black Water'' (Brazil-USA, 1990). A portrait of a Brazilian fishing village, Sao Braz. 9:15 p.m.
''Herdsmen of the Sun'' (Germany-Africa, 1989). A documentary visit with the Wodaabe, a nomadic tribe in the African Sahel. Follows ''Black Water''
Friday, April 19:
''Ceila'' (Australia, 1988). A 9-year-old girl, living in Melbourne, worries about her pet rabbit and her left-wing neighbors at a time when all are in danger. 7:30 p.m.
''Silent Scream'' (Scotland, 1990). The life of Larry Winters, who was imprisoned for the killing of a Soho bartender. 9:30 p.m.
Saturday, April 20:
''Volpone'' (France, 1939). Ben Jonson's Elizabethan classic about the merchant who fakes his death to witness his friends' grief. 7:30 p.m.
''King of New York'' (USA, 1990). Christopher Walken plays a New York crime lord. 9:30 p.m.
Sunday, April 21:
''Johanna D'Arc of Mongolia'' (Germany, 1990). Horse-riding Mongolian women kidnap four Western women on the Trans-Siberian express. 7 p.m.
Thursday, April 25:
''Imago, Meret Oppenheim'' (Switzerland, 1990). The life of the Swiss artist. 7:30 p.m.
''Strand, Under the Dark Cloth'' (Canada, 1989). The life and perambulations of an artist. 9:15 p.m.
Friday, April 26:
''Venus Peter'' (Scotland, 1989). The coming of age in a small fishing town. 7:30 p.m.
''Chronicle of a Death Foretold'' (Italy, 1989). Murder in the name of honor.
Saturday, April 27:
''Paper Mask'' (England, 1990). A hospital porter assumes the identity of a dead physician. 7:30 p.m.
''The Natural History of Parking Lots'' (USA, 1990). A privileged young man in Los Angeles becomes a car thief. 9:30 p.m.
Sunday, April 28:
''The Last Butterfly'' (England, 1990). The story of a mime caught up in World War II. Tom Courtenay stars. 7 p.m.
Courtenay is expected to attend a reception that will follow the screening, and with this, the 22nd Baltimore Film Festival will end.