"Rap is a vocal delivery. Hip-hop is the culture. You can rap and not be any part of hip-hop," he said.
The gangster rap pioneer-turned-actor became a first-time director so that dozens of performers could explain what inspires and influences their style of music.
"It deserves respect. It's an American-born art form. We only have a few things that we do in America. We had jazz. We had blues. We have rock.
It was a movement. It was so new and unique and it came from New York to L.A., and L.A. kind of got swept up by it. Like, if you knew somebody from New York or you could get one of the big belt buckles with a cane, it just took over the country by storm. And no one really knew if it was a fad back then so, 'Eh, it won't be around.' But here we are, 30 years later," he said.
"Something from Nothing: The Art of Rap" is rated R and opens Friday.