This 2002 romantic comedy by Rick Famuyiwa (The Wood) opens with a captivating montage in which more than a dozen recording stars answer the question “When did you fall in love with hip-hop?” Asking them to define it might have provided the grounding for a much deeper story: by the end of the movie “hip-hop” doesn’t signify much more than its buppie lovers’ nostalgia, and all their talk about keeping it real has begun to peel away from the narrative. Still, the picture is smart and consistently funny, with sharp performances by Taye Diggs as a disenchanted record executive, Sanaa Lathan as an idealistic music journalist, Queen Latifah as her straight-shooting friend, and Mos Def as a talented MC who can’t get ahead in a business that remakes a Paul McCartney/Michael Jackson hit as “The Ho Is Mine.” PG-13, 109 min.