Perry Como no longer opens his television programs singing "Dream Along with Me," as he did in the '50s, but the shows are still pretty dreamy. "Perry Como's Spring in San Francisco," the ABC special at 8 Sunday night on channel 7, has its feet up and its collar open and a cool drink in its hand. This is a pretty swell way to spend an hour.

Crosby turned singing into cozy conversation. With Como, it's more the muttered remark. His voice strains and he clearly has no interest in up-tempo ditties like "It's a Miracle," with which he opens the show on a cable car. But later, dressed in a white suit and standing near a grand piano in the elegant setting of the Palace of Fine Arts, Como sings "Send in the Clowns" and reminds the world how much it will have lost when all of the crooners are gone, and almost all of them are.

With Cheryl Ladd, Como visits crooked old Lombard Street and a fortune cookie factory. With Oakland Raiders quarterback Jim Plunkett, an amiable lug, he sails over to Tiburon.At Golden Gate Park, he sings "Not While I'm Around" to a gaggle of adorable Oriental tots. Only an interlude by the plastic-coated country-singing Gatlin Brothers is geniunely boring.

Producer-writer Stephen Pouliot and director Sterling Johnson provide Como with the perfect forum for his matter-of-fact affability, something that age has obviously no hope of withering, no matter what it may do to his vocal chords. A splendid mix of film and tape both glorifies and generously depoliticizes the city, and the street entertainment captured for the camera includes the wonderful Breeze Brothers, one of whom juggles two bowling balls and an egg and the other of whom juggles two swords and an apple -- while eating the apple! Yes, while actually eating the apple!!!!!!!

Thank heaven there's somebody around who remembers what entertainment is.

Como closes the show with "I Left My Heart in San Francisco," sung at sundown with a flute player and the Golden Gate in the background. Perfection. Hours of television this peaceable, polished and nonabrasive should not be as rare as they are. If history teaches us anything, it is that they are bound to get even rarer.