High density digital versatile disc is a digital optical media format which is being developed. HD DVD is similar to the competing Blu-ray Disc. It is currently in a format war with the Blu ray disc proposed by the Blu ray disc association.
HD DVD has a single layer capacity of 15GB and a double layer capacity of 30GB. The surface layer is 0.6mm thick which is the same thickness of surface layer as standard DVDs.
HD DVD media is less expensive to manufacture than Blu ray discs which require re-tooling of DVD production lines. Another advantage over Blu ray is the common disc structure with DVDs which therefore allows for full backwards compatibility of HD DVD drives which will be able to play both DVDs and CDs. However it is now likely that Blu ray drives will be backwards compatible with DVDs.
HD DVD provides the large capacity storage needed for all sorts of recorded content, including high definition movies and music as well as computer data and files.
There are two kinds of of HD DVD discs for content, the 15GB single layer disc and the dual-layer disc with double capacity, a full 30GB. Using the latest compression technologies, the 30Bg disc can store up to 7 hours of images. Today’ DVD has a capacity of 4.7GB and store only 2 hours of standard definition content.
HD DVD discs have a data transfer rate of 36.55Mbps which allows the 24Mbps data stream of digital television broadcasts to be seamlessly recorded.
Using HD DVD in the every day world will have numerous advantage over other optical media technologies. The resilient HD DVD disc has a protective layer which removes the need for a protective cartridge, allowing the development of slim computer drives. The added bulk of a disc cartridge would have also caused any laptops using a cartridge based optical media disc to increase substantially in size to allow for the extra room the drive would need.
Chuck Red runs website on both Blu ray http://www.blueray-media.co.uk and HD DVD formats http://www.hddvd-media.co.uk/