THE FEDERAL COMMUNICATIONS COMMISSION VOTED to freeze allotments of television channels in 30 major metropolitan areas while it studies whether current TV technical standards, set up in 1941, are outdated. Chairman Dennis R. Patrick said the FCC action ``may ultimately result in yet another generation of television technology.'' The FCC noted progress in high-definition TV, which scans nearly twice the number of horizontal lines that make up the usual TV picture. Other advancements, the commission said, range from fairly modest improvements to revolutionary changes. PORTIONS OF THE CANNES FILM FESTIVAL WILL BE SCREENED at the 23rd Chicago International Film Festival beginning Oct. 19. All the films shown during Cannes's International Critics' Week will be presented, as well as ``Aria,'' the closing-night film on which 10 directors collaborated. In all, 30 feature films shown at the French festival will be shown during the two-week event. A HOME VIDEO OF LT. COL. OLIVER NORTH'S TESTIMONY will soon be available for people who were unable to follow the 30-plus hours of the Iran-contra hearing on television. The tape, sold by MPI Home Video, will run about 90 minutes, and the suggested retail price is $19.95. Stores should begin receiving the tapes July 30. Waldenbooks has already made a commitment to carry it.