Next-generation high definition DVD players should be compatible with high definition DVDs burned on present-day Macs with the upcoming DVD Studio Pro 4. Apple had a Toshiba prototype HD DVD player at their NAB booth to demonstrate this.
Because the bitrate for high definition H.264 is similar to standard definition MPEG2, two hours of quality HD material could fit onto a single layer, red-laser burned DVD. The blue laser players (HD DVD and Blu Ray) will also have red lasers in them.
"Apple is committed to both emerging high definition DVD standardsBlu-ray Disc and HD DVD." (This is from the
fourth paragraph of an Apple press release.)