This is one of the major formats of high definition DVDs. These DVDs boast picture quality that is far superior to that found on regular DVDs. The other high definition DVD format, called Blu-ray, is incompatible with HD DVD. So only a Blu-ray player will play Blu-ray disks and an HD DVD player will play HD DVD disks. Several manufacturers have developed players that play both formats, but these are pricey. HD DVD is backed by Toshiba and some major motion picture studios.