Whats different about Blu-ray?
Sony is the primer mover behind Blu-raybut its made every effort to build a strong coalition. The Blu-ray Disc Association includes more than 170 companies, including most of the consumer electronics companies that were on the VHS side in the first recorded video format war. While Blu-ray discs are the same size and thickness as DVDs, the primary information layer is a mere 0.1mm from the surfaceand those discs have a new scratchproof coating to make such fine tolerances workable. The laser spot size is 0.48 micrometers. Single-layer Blu-ray discs store 25GB of data, just over five times as much as single-layer DVDs. Dual-layer Blu-ray discs store 50GB of data. Blu-ray can transfer data at up to 48 mbps. While Blu-ray discs could use MPEG-2, MPEG-4, or VC-1, most initial releases from core Blu-ray backers should use MPEG-2, including all of those from Sony-owned studios, which will aim for an 18mbps data rate. (Warner will use VC-1 for both Blu-ray and HD DVD discs.) Sony claims that M
