For a few months now I have been burning HD DVD's onto SD DVD's. Of course only holds about 25 minutes of HD DVD footage on a SD DVD. These play great on my Toshiba A1. Excellent close to HD DVD quality. Today I bought the XBox 360 with HD DVD add on. None of "fake" HD DVD's I made on SD DVD will play back on the XBox 360 HD DVD add on but King Kong HD DVD played fine. Has anyone else tried this yet? All my HD footage comes from Canon XHA1 cameras that we use in studio.