Available on DVD: “Something From Nothing: The Art of Rap”

"You write complicated rhymes," Ice-T says to Eminem in the film Something From Nothing: The Art of Rap. Do they start out that way, he continues, or do you complicate them?

His question and Eminem’s candid attempt at answering it are what’s remarkable about this star-studded rap and hip-hop documentary, directed by Ice-T and Andy Baybutt. Despite the fluffier and repetitive responses elicited by Ice-T — the old-school rapper turned Law & Order: SVU lead — this is a film that does sweat the technique, with at times illuminating and spirited results.

Not that Eminem whips out a sheet of diagramed lyrics, but we do see someone else’s, while another rhyme slinger surprisingly credits his sense of structure to the high school writing formula of introduction-body-conclusion. Loosely organized by geography, Something From Nothing consists of Ice-T’s visiting famous practitioners he knows, and asking how they do it, and what it was like back in the day.

But he also asks them to show off their skills: Almost everyone featured, from KRS-One and Doug E. Fresh to Nas, Q-Tip and most fiercely Kanye West, freestyles — in unbroken takes — or trades favorite lines or anecdotes from some deeply felt influence.

As history, hitting the usual beats with legendary Bronx origins, East-West distinctions and so on, the film’s account can be shallow. Likewise, the bumper shots of city streets and helicopter views grow tiresome. But when the theory and practice come out in equally full force, Something From Nothing gets closer to the heart of the matter than you might expect from its famous roster.