Ma Rainey's Black Bottom is less about titular blues singer Ma Rainey and the African-American music scene of the late 1920s than previews would have you believe.

The movie, based on the Pulitzer Prize-winning play by August Wilson, is more about her trumpet-playing sidekick, Levee. Rainey was a real person, an icon of the genre, hailed as the "Mother of the Blues." Levee is a fictional addition -- a montage, of sorts, of black musicians of the era. The story is more about him than her, and the movie takes place almost entirely in a dingy Chicago recording studio where Rainey and her band are recording the title song.

Rainey, masterfully played by Viola Davis, is bloated with arrogant self-importance, well aware of her place in music history and unwilling to compromise on even the smallest detail of her craft. Levee -- played brilliantly by Chadwick Boseman, in what would be his final performance -- is confident of his own abilities, sure of his future greatness, but weighted down by his own dark past. (Boseman, who died shortly before the movie's release after a four-year battle with colon cancer, concealed his failing health from fellow cast members while filming.)

The movie is very obviously an adaptation from the stage; the staging and the dialogue makes its origins clear. Action junkies will complain that the movie treads slowly, there's a touch of action here and there, but it's mostly talking, some shouting, a lot of smoking and, here and there, making music.

The music -- both the full-blown performances and the in-studio noodling -- will stand out most while you're watching, but it's some of the dialogue - and a few revealing monologues -- that will stick with you long after the credits roll. The movie isn't just about Rainey and her sidekick musicians -- it's about the black experience in the 1920s, when prejudices were often much more open than they are today (or were, until recently). There's some raw pain as Levee and the other musicians start talking about their lives outside of the music.

Besides Levee, the band consists of trombonist Cutler (Colman Domingo), pianist Toledo (Glynn Turman) and bassist Slow Drag (Michael Potts). Each brings something different to the table, most of which is revealed while they're rehearsing in a claustrophobic basement room under the studio. Some of it is light banter, but there's anger and bitterness, too -- and the movie takes a dark turn before it's done.

The band is joined by Dussie Mae (Taylour Paige), a dancer and a love interest for -- well, a couple of the characters -- and Sylvester (Dusan Brown), Rainey's nephew who has been promised a speaking part on the recording despite a debilitating stutter. Meanwhile, above them all, are Mel Sturdyvant (Jonny Coyne), the producer, and Irvin (Jeremy Shamos), the agent, who don't quite know how to cope with Rainey's group of black southern musicians.

A lot is revealed through the script, and the music of course is exceptional. Kudos to Maxayn Lewis, who belted out the songs in Rainey style (Davis, it turns out, did not do her own singing), and Branford Marsalis, who wrote the score and produced new arrangements of Rainey's songs.

And Levee, he does love those new shoes he bought....