Most studios have already picked a side in the HD DVD
war, but for the few still contemplating a near suicidal attempt at a simultaneous DVD, HD DVD and Blu-ray release, there's help on the way. A pair of Warner
engineers have been working on a way to get all three formats to hold hands on a single disc, and have recently filed a patent to that effect. This is made possible by the fact that Blu-ray uses a 405nm laser to read its 0.1mm deep info layer, while HD DVD uses the same blue laser
wavelength at the depth of 0.6mm. The hybrid disc works by making the Blu-ray layer act like a two way mirror, reflecting enough light for Blu-ray playback, but letting enough light through for HD DVD operation. As for DVD, that layer can be found on the flip side of the disc. Of course, the new format will cost more to produce than your standard next-gen disc, and we're not quite sure this isn't all madness to begin with, but we suppose we'll have to play the game if we don't want to end up buying every title in triplicate.
[Via New Scientist