HP, until now a staunch backer of Sony's Blu-ray format, has formally embraced HD-DVD, the next generation optical disk format from Toshiba.

The PC maker will no longer support the Blu-ray disc exclusively, but will also join the HD-DVD Promotion Group.

The move is thought to be because Blu-ray would not adopt two additional features requested by the computer company.

In a statement on its site HP has said: “Previously, HP supported the Blu-ray Disc format exclusively. The company had requested the Blu-ray Disc Association adopt two customer-friendly technologies, Mandatory Managed Copy and iHD, which are already included in the HD-DVD format".

Only Mandatory Managed Copy, which permits consumers to make legal copies of video content, was formally adopted by the association. iHD, which allows content providers to offer greater interactivity on next-generation DVDs and helps ensure a more compelling user experience when recording HDTV programs or moving digital content throughout the home, was not approved for launch.

HP believes both Mandatory Managed Copy and iHD are important to fostering the digitally connected home; both of these technologies are incorporated into HD-DVD.

Microsoft has already announced plans to integrate iHD into its new Windows Vista operating system.