How time flies! It seems like only yesterday when Agnes Varda's "One Sings, the Other Doesn't" was being rated from various quarters as an important film, maybe even a seminal work of art. Make that an ovular work of art, in deference to the singing heroine, who often rhapsodizes about her ovules. There was even some loose acclaim to the effect that "One Sings" represented neofeminist self-expression at its most enlightened and transporting. . . .

Given the disillusioning insanity of the movie itself,it's probably just as well that the local opening was delayed. Within a matter of months, "One Sings," now at the Outer Circle 2, has plummeted from the status of a social and artistic pathfinder to a laughable period piece. Overnight sensations one can understand, but an overnight period piece?

Varda evidently conceived her film as an inspirational fable for the heiresses of Women's Lib. The heroines, a hoydenish redhead known by her nickname, Pomme (Valerie Mairesse), and a reserved brunette called Suzanne (Therese Liotard), are meant to illustrate the contrasting but equally desirable and upward-leading paths to contentment and fulfillment supposedly beckoning to Today's Aware Woman.

Pomme, the one who sings, or thinks she does, symbolizes bohemian, artistic, nomadic impulses. Suzanne, the one who doesn't sing, not that it matters, since 99 percent of the world's population must sing better than Pomme, represents the flip side of Varda's counterfeit memorial coin. In addition to being Pomme's temperamental opposite, Suzanne also exemplifies nest-making, socially conscious, bourgeois tendencies. Ostensibly, the scenario chronicles their lives from 1962 to 1976, during which time they progress from girlish confusion and insecurity to womanly maturity and self-esteem.

Varda seems to have undertaken the film in such a virtuous, euphoric mood that she failed to notice how cliched her protagonists were and how inadequately their would-be exemplary histories were illustrated. Indeed, the illustrative material is so superficial and frequently absurd that one begins to wonder if the movie could be some guy's hoax. It does not seem like the work of the same woman who directed such adroit and distinctivley faminine movies as "Cleo From 5 to 7" and "Le Bonheur."

Pomme's singing career is ludicrous, but we're meant to take it seriously. Beginning in the chorus of a rock 'n' roll act, Pomme emerges as a feminist street singer, the lead in a barnstorming quartet that baffles minuscule crowds with cloying pantomimes and stupefying lyrics. For example, this tribute to pregnancy: "Oh, it's good to be a bubble, a beautiful balloon, a workshop for molecules, a beautiful ovule, a cell factory . . . Oh, it's good to be a fat dream, a green tree loaded with sap, a rising loaf of bread, a cookie with a fortune inside . . . " Ad nauseam.

A revival of any fo the versions of vintage "women's pictures" like "Back Street" or "Madame X" would inspire livelier interest than "One Sings," The period patina and the compromises stemming from stricter mores and censorship wouldn't obscure the fact that the heroines of such films confronted tangible social and emotional obstacles.

Varda's film lacks convincing sources of conflict. It's a soap opera without savvy. One can't get involved in what Varda, in the course of a voice-over narration that is overburdened with explanation and summary, describes as her characters' "fight to gain the happiness of being a woman." The struggle is never plausibly or adequately dramatized.

Varda doesn't even sustain the illusion of a double friendship between Pomme and Suzanne. They're soulmates by definition, by virtue of their sex. It's even less convincing when Varda as narrator applauds Suzanne for feeling a sense of solidarity with her female co-workers when she takes a factory job to help support her illegitimate children. If she formed any factory friendships, we don't see them, either at the time or later, when Suzanne has been promoted up the rung of self-fulfillment to director of a family planning clinic and bride of a - what bliss! - doctor.

Despite its progressive tone, oddly reminscent of Soviet films that used to enthuse over the brighter day ahead and urge their publics optimistically onward, "One Sings" represents a regression in every crucial respect. Varda's characters would fit easily enough into one of the new TV sitcoms built around female roomies or sidekicks, with one on the brash side and another on the serious side.

"One Sings" might as well be an antifeminist ract, since it trivializes the issues it meant to memorialize. Perhaps Varda never outgrew her infatuation with such late '60s bohemians as Viva and the composers of "Hair," a fascination that resulted in an earlier period piece called "Lions Love." Whatever the cause, her work now seems instantly dated. Like Pomme, she can't carry any of those songa y dated. Like Pomme, she can't carry any of those songs she's so eager to sing.