Also, while all these BD discs sort of have the same structures, there are differences between AVCHD, BD and UHD BD discs. If you look at the headers of the files that hold the meta data (bdmv, clpi, mpls) about what the disc is, you can see different values:
AVCHD : 0100 (I forget what AVCHD V2 is)
BD : 0200
UHD BD : 0300
At present if you try to play a UHD BD in MC you will get some oddness (stream names are Unknown etc) as it cannot parse the 0300 files correctly to get this info (even though the M2TS will play). The updated version does.