Wayne Stallwood wrote: snip
Regarding legality I think the main issue is that any open library that was obtained through reverse engineering of the CSS algorithm may be subject to legal issues via the DMCA. This is of course fairly US centric, I think in this country as long as you don't use it as a tool of copyright infringement you are fairly legal.
I think it is primarily a licencing issue. ISTR there is one Linux distro (Lindows?) that includes a fully licenced legal anywhere decoder in the price.
Ian