Branford Marsalis’ recent hiring as leader of the Tonight Show band isn’t mentioned in this 58-minute film The Music Tells You, but it gives you some understanding of why he took the gig. He grumbles frequently about the nonstop touring that is the life of a jazz musician. You also see why codirectors D.A. Pennebaker (Monterey Pop) and Chris Hegedus — not to mention NBC — were attracted to Marsalis; he’s charming, articulate, and candid. Unfortunately, the filmmakers show little interest in his art. Only one musical selection (an extended version of Marsalis’ ”The Beautiful Ones Are Not Yet Born”) is heard from beginning to end, and none are identified. During one scene, Marsalis enthuses about playing ”The Star-Spangled Banner” with pianist Bruce Hornsby at a football game; we get to hear only five bars of the performance. The result is an essentially superficial road tour — autograph signings, Q&A with students, backstage grousing — with only occasional insights into the subject or his music.