Question: what is the difference between blu ray and hd dvd?
Answer: Blu-ray and HD DVD both use a blue laser, which has a shorter wavelength than red ones. ... In contrast, HD DVDs can store up to 15GB on a single layer while Blu-ray can hold 25GB on one layer. Even more can be packed into Blu-ray/HD DVD discs if they use more than one layer or one side of the disc.