‘Ma Rainey’s’ director on celebrating artists now gone

Gertrude “Ma” Rainey, called the mother of blues, helped expand the universe of American music. Director George C. Wolfe talks to Jeffrey Brown about the new film about her life, based on the play by August Wilson, and how it celebrates the legacy of three great American artists: Rainey, Wilson and Chadwick Boseman, who starred in the film before his death earlier this year.