If you don't already know the history of the American civil-rights movement (seriously?), of how everyday folks became nonviolent freedom fighters in a valiant attempt to end racial discrimination, here's one more opportunity to catch up. Other documentaries have more richly fleshed out that chaotic time—from the Montgomery bus boycott to Martin Luther King's assassination—but Nanking directors Bill Guttentag and Dan Sturman at least figured out a new throughline to retell this vital tale: the anthems of the day. Presenting the timeline through talking-head testimonials (Andrew Young, Julian Bond, Harry Belafonte) and still-moving found footage, Soundtrack makes pit stops along the way so that contemporary artists may reinterpret the spirituals and folk songs of the day as glossy in-studio videos. Sometimes the juxtapositions are moving, as when the Roots stir up "Ain't Gonna Let Nobody Turn Me Around" while we see King leading the march on Selma, or when soulful whitey Joss Stone kills it on "Eyes on the Prize." But more often than not, these musical interludes are more like distractions aimed only to entice younger audiences (not a terrible thing), and the final inclusion of Obama's photo is so heavy-handed that a snapshot of the post-election Onion headline "Black Man Given Nation's Worst Job" would have been more resonant.