FREEZE FRAMES

COBRA -- Another slimy tract from Sylvester Stallone, whose once-promising career has become one of the decade's biggest cinematic embarrassments. This time he instructs us on the desirability of letting cops ``do what's necessary'' with no cowardly whining about ``rights of the accused.'' To prove his point, he wipes out an ``army of psychos'' that would otherwise be terrorizing our own backyards at this very moment. Stallone wrote the screenplay and plays the title role. The director is George P. Cosmatos, who also guided Stallone through the subtleties of ``Rambo: First Blood Part II,'' and hardly knows where to point the camera. The music is as thudding as the violence; the editing is so manic it sometimes fails to make sense. (Rated R) A GREAT WALL -- When his promotion doesn't come through at the office, a San Francisco computer expert decides to chuck it all and go on a Chinese vacation with his wife and teen-age son. The twist is that he was born in China, although he left there 30 years ago and has become a stranger to the place. Both comedy and poignancy grow from the blend of respect and bewilderment felt by his American-born family and their relatives in the old country. Some of the performances are too broad, and the story doesn't flow as smoothly as it might, but there's a friendly atmosphere to this first American feature shot on location in China. Written and directed by Peter Wang, who also plays the leading role. (Rated PG)

SIGNAL 7 -- A day in the lives of two middle-aged San Francisco taxi drivers who dream of becoming actors. As the loosely constructed story shows them on the job and going through a stage audition, we get isolated glimpses of their personal lives and emotional problems. The performances are so vivid that you feel you've known these guys half your life, and director Rob Nilsson has accentuated the realism by shooting in video, then transferring the images to grainy 35-mm film. The visual appearance of the picture isn't very appealing, but it has an immediacy that helps cover gaps in the plot and raunchy moments in the improvised screenplay, which was shot on the run in a mere four days. Dedicated to John Cassavetes, whose commitment to personal cinema was evidently a strong influence on the project. (Not rated)

SONS OF SHIVA -- Filmed in India and using a minimum of narration to explain its extravagant images, this expressive documentary depicts Bengali worshipers holding a three-day series of rituals. Directed by Robert Gardner in collaboration with 'Akos "Ost"or. (Not rated)

WHAT HAPPENED TO KEROUAC? -- A sad, funny, irreverent documentary about the most famous and controversial of the ``beat generation'' writers, who sparked a revolution in prose before drinking himself to death in 1969. Framed by a sometimes foul-mouthed interview with Gregory Corso and peppered with appearances by everyone from beat survivors Allen Ginsberg and William S. Burroughs to media personalities William F. Buckley and Steve Allen, all of whom crossed Kerouac's path at one time or another. Directed by Richard Lerner and Lewis MacAdams. (Not rated) RATINGS: Films with ratings other than G may contain varying degrees of vulgar language, nudity, sex, and violence.