I've compared the 25p blu-ray release of Wonders of the Solar System (BBC docu) and its 24p versions. Narrator Brian Cox's voice and (I think) the on-location audio is pitched down for the 24p versions, but the soundtrack's music is different, so apparently there's mixed content. If you want Cox's voice right, you have to speed up the music, and vice versa. Damn BBC changing everything for the American versions. At least they kept the main narrator's voice now, but probably only cause he's in the video talking.