Versatile Multilayer Disc
Versatile Multilayer Disc, or VMD, is an optical disc format dveloped by New Medium Enterprises, Inc. (NME) for use in their HD VMD movie format. HD VMD is intended to be a high definition replacement for DVD, but so far has gained little momentum outside of India, where a market for players and (local) movies has gained some momentum.
Unlike the more popular Blu-ray format, VMD is based on additional capacity (layers) using a red laser drive based on standard DVD technology. Blu-ray uses a more expensive blue laser, and requires much greater precision, resulting in a corresponding increase in manufacturing costs for both drives and discs.
HD VMD CapacityRather than improving the laser, VMD adds layers beyond the standard 2 used for DVD-Video. NME claims VMD discs can include up to 20 layers, for a theoretical maximum size in excess of 100GB. However, this claim has yet to be tested. Currently discs that store approximately 20GB (4 layers). By comparison, Blu-ray allows up to 25GB for a single layer disc or 50GB for dual layer.
ThroughputVMD is designed for higher throughput on standalone video players than older DVD technology. This is necessary in order to deliver the 1080p video and possibly future lossless audio commonly used in Blu-ray. Video throughput of up to 40Mbps (40 Megabits or 40 million bits per second). This is equivalent to Blu-ray, and far superior to standard DVD-Video's 9.8Mbps.
Manufacturing CostsUnlike Blu-ray discs, which require completely different assembly lines to manufacture than standard DVDs, VMD is similar enough to standard DVD media that manufacturing operations can be upgraded for VMD at a much lower cost. Likewise, by using lower cost (already available) red lasers, the cost of manufacturing drives is also much lower. The first public demonstration of VMD playback used a regular DVD-ROM drive to read a dual layer disc. The company reports a computer drive is being developed for reading 4 layer VMD discs.
For more details on the HD VMD movie format, make sure to read its Glossary entry.
HD VMD Timeline (as of 3 March 2008)
4 February 2007 - New Medium Enterprises to offer HD VMD format