Alan Parker’s “The Commitments” is a loud, rollicking, comic extravaganza about a rock band from the poorest precincts of North Dublin that decides to play soul music. The organizer of the band is the lean, ingenious Jimmy Rabbitte, whose suggestion is greeted with puzzlement by his friends. They like soul music, yes, but they don’t particularly identify with it. Rabbitte’s logic is persuasive: “The Irish are the blacks of Europe. Dubliners are the blacks of Ireland. North Dubliners are the blacks of Dublin.” The movie is based on a novel by Roddy Doyle and the music is honest. “The Commitments” is one of the few movies about a fictional band that’s able to convince us the band is real and actually plays together, it is filled with life and energy.