It's buried in the chip, along with native HDCP support. The firms just need to pay half a cent to Intel for a key embedded in the card bios and you get yourself a HDMI/HDCP capable card.
Nvidia and ATI are paying a $10.000 annual membership fee and they are willing to pay four cents for the HDMI royalty as well.
The only catch is that you need to make the PCB to include the HDMI connector on a graphic card. This should not be a big problem as, video-wise HDMI is DVI - it works the same way, just the connector is different, and it can drive a audio signal while DVI can't. µ