Blu-ray or BD, is the name of a next-generation optical disc format. Blu-ray is named after the underlying technology, which utilizes a blue-violet laser to read and write data. The capacity of a Blu-ray disc is 25GB (single-layer) and 50GB (dual-layer). That means with Blu-ray you can store over 9 hours of high-definition (HD) video on a dual-layer disc. Blu-ray supports 1920 x 1080 video resolution, and Microsoft VC-1, MPEG-2, MPEG-4 AVC (H.264) video formats. See also HD DVD