The band appears really to be playing, at least when they are not the focus of attention. When on camera, they ham it up, probably at the goading of the director. Nobody looks to be in blackface. The pianist is a white guy - probably Greek - so if HE isn't corked up, NONE of them are. Yeah, I wish we could hear them. Jelly Roll Morton's Red Hot Peppers are a "Sweet Substitute" for a soundtrack!