no sound with movie x264

I want to look at a blu ray movie with 1080P and x264. But when i start the movie in XBMC i dont have any sound at all.
Do i need to install something to make this work?

Many thanks

It’s possible you need to encode the video with these audio channels.

I’m not encoding the movie.

I’m not familiar with how Blu-Ray discs sort their files. Do they use the same Video_TS folder that DVDs do?