From El Reg:

Speaking in Australia this week, Microsoft Senior Program Manager Steve Riley effectively revealed Windows Media Player 11 will not play HD content from HD DVD or BD sources unless it’s running under a 64-bit version of Vista. According to Riley, 32-bit mode is too open to hacks designed to bypass the optical discs’ copy-protection mechanisms.

Given MS’s current current track record with security, it remains to be seen how effective this push to use the UnTrusting Computing platform will be for this..

According to Riley, the decision to drop 32-bit HD DVD and BD playback from WMP 11 was made because “the media companies asked us to do this”. What’s more, he added, “they don’t want any of their HD content to play in [32-bit] at all, because of all of the unsigned malware that runs in kernel mode can get around content protection”.

So presumably anyone else not MS who wants to beg leave to create an official player is going to have to play along with the media companies attempts to wrest control of your computer from you.

It also probably means that Apple Mac users will have to buy 64-bit Intel Macs if they want to be able to watch this new content and high quality (as I don’t believe that the PowerPC line of processors supports the lock in that Hollywood requires).

With Sony and Toshiba supporting BD and HD DVD playback, respectively, on select PCs running 32-bit Windows XP, playing content from pre-recorded discs may not seem to be much of a problem. But it will become more of an issue once content companies begin enforcing region coding and HDCP compliance for full-resolution output. That may require new software for playback, and the updated code could well meet Hollywood’s demand for 64-bit computing.

Given that I don’t run Windows anyway, the whole question is likely to be moot..