Pretty much the only way the 990 could decode HD-DVD is if HDMI Audio inputs were added and most probably a major processor upgrade. Not an easy feat with the present platform. Having said that with 7.1 analog inputs you would not be decoding HD-DVD in the 990 but rather in the player. It is really unknown at this time whether either of the HD DVD formats will support analog HD audio or if HD audio will only be output over HDMI.