Blue-ray disc (BD) is a next generation optical disc format meant for storage of high definition video and high –density data. As compared to the HDVD format, its main competitor, Blu-ray has more information capacity per layer, 25 instead of 15 gigabytes. Blu-ray dics not only have more storage capacity than traditional DVDs, but they also offer a new level of interactivity. Users will be able to connect to the internet and instantly download subtitles and other interactive movie features.

Blu-ray gets its name from the shorter wavelength (405 nm) of a “blue” (technically blue-violet) laser that allows it to store substantially more data than a DVD, which has the same physical dimensions but uses a longer wavelength(650 nm red laser).

There are plans for BD-ROM (read only), BD (recordable) and BD-RE (rewritable) drives for PCS and with the support of the manufacturers, it’s very likely that the technology will be adopted as the next-generation optical disc format for PC data storage and replace technologies such as DVD+-R, DVD+-RW, and DVD+-RAM.

INTRODUCTION TO BLUE-RAY DISC

A current, single-sided, standard DVD can hold 4.7 GB (gigabytes) of Information. That's about the size of an average two-hour, standard-definition movie with a few extra features. But a high-definition movie, which has a much clearer image (see how Digital Television Works), takes up about five times more bandwidth and therefore requires a disc with about five times more storage. As TV sets and movie studios make the move to high definition consumers are going to need playback systems with a lot more storage capacity.

Photo courtesy BIu-ray Disc Association BD-ROM disc researcher

Blu-ray is the next-generation digital video disc. It can record, store and play back high definition video and digital audio, as well as computer data.

The advantage to BIu-ray is the sheer amount of information it can hold:

· A single-layer BIu-ray disc, which is roughly the same size as a DVD, can hold up to 27 GB of data that's more than two hours of high-definition video or about 13 hours of standard video.

· A double-layer Blu-ray disc can store up to 54 GB, enough to hold about 4.5 hours of high-definition video or more than 20 hours of standard video ..