A filmmaker of color is almost certain to win this year's Oscar for Best Documentary Feature. In fact, for the first time, African-American documentarians made up most of the nominees. We talk with Ava DuVernay, whose movie "13th," made her the first black female director to be nominated in this category. And the Emmy and Peabody award-winning documentarian Noland Walker, now of ITVS, tells us about how the film industry has responded to documentarians of color since he started as a production assistant on the landmark PBS documentary series, "Eyes On the Prize" in the late 1980s.