Must be some weird kind of format if it doesn't show up in either
Ubuntu or Windows - unless the files are hidden ??? However since the
DVD's play on a standard DVD player the format isn't too esoteric,
it's just a case of finding out what it is ( easier said than done ).

Did you install the libdvdcss2 package ? That's the one that allows
access to encrypted DVD's.

Ubuntu only shows a floppy or CD/DVD drive when there is readable media present - just a different way of doing it to Windows, and how annoying to see the DVD drive but get the 'not ready' message trying to open it. Far better to not have the drive visible if there's nothing to open ??