The HD DVD name is derived from its origination as a high-definition extension of the DVD optical disc format. A HD DVD disc can store substantially more data than a DVD, because of the shorter wavelength (405 nm) of the blue-violet laser (DVDs use a 650-nm-wavelength red laser and CDs an infrared 780 nm laser), which allows more information to be stored digitally in the same amount of physical space.

In comparison to Blu-ray, which also uses a blue laser, HD DVD has less information capacity per layer (15 gigabytes instead of 25), though HD DVD is easier and cheaper to manufacture than a Blu-ray pre-recorded disc due to its sharing of the same basic disc structure as a standard DVD: back-to-back bonding of two 120 mm diameter substrates, each 0.6 mm thick. The 30 GB dual-sided HD DVDs have been used on nearly every movie released in this format. On the other hand, Blu-ray has only released movies on 25 GB single layer discs.