There is no such thing as a HD "Video DVD." There are ways to put AVCHD onto DVD but the player must be some PS3, PC, Apple, or smart player. If the player is a DVD video player, it won't play in HD.
You should open a Discussion rather than a How-To since there is much to discuss. For example, the details of the system that will play this.
How do I make an 'excellent' DVD from a AVCHD file? I can make so-so DVDs from iMovie but they seem to be in 480i. Is my computer too slow?