Editor: BackupHDDVD is a tool which decrypts HD DVD files. It is not a crack for AACS as widely reported, the software merely does what any HD DVD Player does.. decrypt the content with a legitimate key.
The challenge is getting that key. You may recall that the first DVD rip software used a player key extracted from the Xing DVD player software - a key that was later removed by the CSS licensing committee. dvd fab express
Then came rippers that brute-forced a valid key (VobDec being the first one), and finally software like DVD Decrypter which can do pretty much what any software DVD player does to get the proper key. Considering AACS looks quite robust, brute-forcing keys is unlikely, but there might be other ways in the future. For now, getting a valid key will be the major challenge to enable access to HD DVD discs.
BackupHDDVD is a java based command line utility that decrypt video files (.evo) from a HD DVD disk that you own, to your hard drive and you can play them back with a HD DVD player software.