Nice, like the color choice and the simplicity. Personally i'd shift the "a film by.." text at the top to the left of the white vertical separation I think it would feel a bit more balanced. Also I think you could kill the drop shadow on "jazz" (and the stars) Everything else is so bold and I think it takes away from that.
To be honest as a Jazz fan this poster doesn't make me want to go see the film. It's a nice central image though. We had our poster done by www.whatisbobo.com and one of the most important parts of the poster is to use proper film poster fonts.