DVDFab HD Decrypter does not compress, even on standard dvds.
You definitely don't want to compress Blu ray high definition dvds! That's defeating the whole purpose of high definition movies.
Besides, the Blu ray blanks cost so much, it's cheaper to buy another copy of the movie. The Blu ray burners are very expensive too.
This is the cheapest one I've seen so far, but I haven't really been looking either:
http://www.newegg.com/Product/Product.aspx?Item=N82E16827106037
I'm not sure about the full retail version, but the free version does not compress, unless they've added that feature to the newest version. I've gotten the popup when opening, saying there's a new version, but I haven't got it yet.
In my version (3170), the choices are DVD9, HD-DVD, or Blu ray Disc.
There's nothing about DVD5.........
I've never known it to do it either. I've always had to run it through Shrink, or CloneDVD, to compress the files it created.