Nearly 20 years after Peter Gabriel emerged fronting an early incarnation of Genesis dressed as a Mr. Potato Head, he has turned into one of the most earnest guys in contemporary rock & roll. He's been doing lots of humanitarian work and some marvelously sophisticated music. Unfortunately, he's also become something of a rock Kipling: His multicultural dabblings have a whiff of Noble Savage condescension. Peter Gabriel: POV, executive-produced by Martin Scorsese, is a document of a 1987 concert gig in Athens. It catches Gabriel running through some of his better-known solo numbers ''Biko,'' ''Solsbury Hill,'' ''Shock the Monkey'' with a crack band and waxing politically correct about South Africa. The rest is standard backstage filler reminding us once again that the concert video is a form fast approaching meaninglessness. The music sounds fine, however, so perhaps we should think of PoV as just a nice greatest-hits tape with lame accompanying visuals, and enjoy it with the picture turned off.