The setting is a Chicago music studio in 1927, where the “Mother of the Blues” Ma Rainey (Viola Davis) and her band are meeting to record several of her hits, though that business is frequently disrupted by the tensions within the group over matters both personal and artistic. Wolfe brings August Wilson’s Pulitzer Prize winner to the screen, quite faithfully - which is just fine, as a play this good requires little in the way of “opening up,” so rich are the characters and so loaded is the dialogue.