The main feature of the Blu-ray disc that separates it from a normal DVD is its storage capacity. The Blu-ray disc has five times more storage capacity than DVDs. It can hold 25GB in a single layer disc and 50 GB on a dual layer disc. A Dual Layer Disc can have over 9 hours of high-definition (HD) video on a 25GB disc and over 22 hours of standard-definition (SD) video can be had on a 50GB disc. The Blu-ray disc also offers other great features,chief among these being a new dimension of interactivity which allows you to connect to the internet and download a wide variety of content.
In addition, you can also record HDTV without resulting in any loss of video or audio quality. And Blu-ray has a transfer rate of data of 36Mbps (megabits per second) so with a Blu-ray disc 25 GB of data can be recorded in around one and a half hours. Essentially the Blu-ray disc is able to accomplish this because of the way it is manufactured and how it reads the data stored on the disc. The Blu-ray Disc is 1.2 millimeters thick, same as a DVD.
With Blu-ray, data is stored directly on top of a 1.1mm thick polycarbonate layer, then a protective hard coating layer is put on the outside of the disc. This differs from a DVD in that, data is stored on a DVD between two 0.6 mm polycarbonate layers. This stacking of layers can cause the laser used to read the data, to split into two different beams, resulting in problems reading the disc correctly. Having data stored on top prevents the Blu-ray disc laser from splitting.
The laser used to read the data is the main technical development that separates the Blu-ray from the DVD. Video and Audio data is stored digitally on spiral grooves which run from the middle of the disc to the outer edges. To play the disc a laser is needed to read these grooves. The smaller the grooves the more data can be stored on the disc, however, with smaller grooves a more precise laser is required.
Unlike the DVD, which uses a red laser, the Blu-ray uses a Blue Laser. This blue laser has a shorter wavelength. The beam is more precise and can read the grooves on the Blu-ray disc which are made twice as small as the ones on a regular DVD. This is why the Blu-ray disc can hold so much data and contain so many new features. For these reasons, the Blu-ray disc will probably become the medium of choice for the foreseeable future, until something better comes along.
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For more information on Blu-ray and Blu-ray Players try this handy comparison guide: bluray players Or view our Videos on our Blu-ray YouTube Channel here: top 5 blu-ray players Copyright 2010. This article may be freely distributed if this resource box stays attached.
