Software player developers have teamed up with HD DVD and Blu-Ray protection companies in an attempt to strengthen the protection of keys used to encrypt data on these discs. The key feature will be the addition of a small program on the disc which will communicate with your PC video player. If your player is not fully patched, it will disable its ability to play hi-def films.
Companies like Corel have announced that they are ready for the new batches of discs containing the new protection, and InterVideo will be one of the first that will require patching.
Most users can now easily rip data from hi-def discs, and multiply them in as much copies as they want. Some countries don't think that copying only one disk is piracy as by their laws you may make one backup disc.
It is unknown if the patching process will somehow compromise users privacy.