Prince's "Sign o' the Times" film did pretty well in its national opening last weekend (250 screens in 30 major cities) and could provide a much-neededboost for his double album of the same name. Billboard points out that Prince's albums have so far reflected the success of their attendant films. For instance, 1984's "Purple Rain," the semiautobiographical film that expanded Prince's audience from a cult to a mass, grossed close to $70 million and the album sold 13 million copies worldwide, 10 million in the United States alone. Last year's "Under the Cherry Moon," in which Prince tried to play both Fred Astaire and Ginger Rogers, grossed only $10 million and the album sold fewer than 2 million copies. "Sign o' the Times" has been certified platinum with sales of 1.4 million and is currently No. 64 on the charts, though a fourth single from the album (and film), "I Could Never Take the Place of Your Man," is moving up the charts.

Meanwhile, insiders at Warner Bros. are buzzing about "The Black Album," tentatively scheduled for release Dec. 8. Although Prince's name isn't on it, it's on his Paisley Park label and is reportedly a return to the hard funk of his "Dirty Mind" period, right down to "adult content" stickers. The title comes from the album's solid black cover (a` la the Beatles' "White Album") but may also reflect Prince's recognition of his original core of black fans, many of whom abandoned him as he experimented with neopsychedelic rock formats on his "Around the World in a Day" and "Parade" albums. As one industry wag put it, underneath all the psychedelic trappings, Prince always did wear his black bikini.

Madonna's Video Slide

On the distaff superstar front, Madonna may have established a new, somewhat dubious record when her latest cinematic opus, the dreadful "Who's That Girl," made the transition from movie houses to video stores in less than three months, despite a much publicized world concert tour. The video version was originally scheduled for the first quarter of 1988, but since the film only did marginal business, the release was accelerated. Will people pay $2 when they wouldn't pay $6? Warner Home Video is hoping they will, and charged retailers $89.95.

What might have been a better product -- a "Madonna Live in Japan" concert video shot in June at the opening of the "Who's That Girl" tour -- apparently won't make it to the American market. The 16-song video is twice as long as her successful "Virgin Tour" video and was recorded in digital stereo; some 60,000 copies have been sold in Japan, which apparently has many yens for Madonna. Warner Reprise Home Video says there are no plans to release it anywhere else. Meanwhile, Sire Records has just released "You Can Dance," featuring six extended remixes of Madonna's dance hits and one new song, "Spotlight." The album is segued for continuous play, and the cassette and compact disc versions include extra dub mixes.

George Harrison Takes on Nike

George Harrison is a party to the multimillion-dollar suit filed by lawyers for Apple Corp. against Nike and Capitol Records for using the original Beatles version of "Revolution" in its ads (a second one recently hit the airwaves). The once-quiet Beatle has also spoken out against the Beatles' music being used to sell "sneakers, deodorant" and so on. Some of the blame has been directed at Michael Jackson, who controls "Revolution" and much of the McCartney-Lennon catalogue, though Jackson reportedly granted publishing rights only after being assured that Capitol and Yoko Ono approved of the arrangement. One song Jackson doesn't control, however, is Harrison's "Something," which recently showed up in a Chrysler spot. It's also worth remembering that all those Buddy Holly songs showing up in commercials are owned by none other than Paul McCartney! On a happier note, Harrison's "Cloud Nine" album, his first in five years, jumped to No. 23 on the charts in its second week, a big improvement on his last album, "Gone Troppo," which peaked at No. 108.

The Jazz Czech Point

Sonny Rollins has been added to the Jazz Freedom Concert to be held next Monday night at the Duke Ellington School of the Arts. The concert, featuring the Billy Taylor Trio, the Dwike Mitchell/Willie Ruff Duo and other musicians as well as authors Kurt Vonnegut Jr., Rod MacLeish, E.L. Doctorow and Czech-born Joseph Skvorecky, was organized to express support for Czechoslovakia's beleaguered Jazz Section, an organization of jazz enthusiasts that sprang up in the wake of the Soviet invasion of 1968. The Jazz Section's main projects were a pair of jazz magazines and festivals of jazz and experimental music, but the organization was abolished in (ironically) 1984 and two of its leaders were given 16-month prison sentences in March for "illegal economic activities." Monday's concert will be recorded and also broadcast live to Eastern Europe by the Voice of America.