ATI has been hit with a Class Action lawsuit alleging the company deliberately misled consumers by claiming a number of its graphics cards complied with the HDCP anti-piracy system, when in fact they weren't.

The complaint, filed in San Jose, California, was made by Stanley Batsalkin and Kenny Vargas on their own behalf and on that of other ATI customers. They maintain ATI's claims that certain graphics cards were "HDCP-ready" or "HDCP-compliant" were false.

HDCP support is essential for the playback of protected HD content. The complaint alleges that many people bought these ATI-based cards in the anticipation of being able to use them to play protected HD content with Windows Vista. They will not be able to do so, the lawsuit alleges.

The veracity of ATI's HDCP support claims was questioned by a number of enthusiast websites earlier this year. Shortly after, ATI removed references to the copy protection technology from a number of its GPU spec sheets.

HDCP-compatible graphics cards must contain a unique encryption key, used by the GPU to encode the video signal. The key isn't a feature of the GPU but of the board, so it's up the the board maker to incorporate the key in their products if they want to claim HDCP compliance. ®