Tuesday, April 21

Blu Ray Disc


About BLU-RAY DISC:- :-

Optical disks share a major part among the secondary storage devices. Blu-ray Disc is a next-generation optical disc format. The technology utilizes a blue laser diode operating at a wavelength of 405 nm to read and write data. Because it uses a blue laser it can store enormous more amounts of data on it than was ever possible.

Data is stored on Blu-Ray disks in the form of tiny ridges on the surface of an opaque 1.1-millimetre-thick substrate. This lies beneath a transparent 0.1mm protective layer. With the help of Blu-ray recording devices it is possible to record up to 2.5 hours of very high quality audio and video on a single BD.  

Blu-ray also promises some added security, making ways for copyright protections. Blu-ray discs can have a unique ID written on them to have copyright protection inside the recorded streams.

Parameters for HD Video Storage with Optical Disks

1.Optical Parameters
2.Disk Structure Parameters
3.Data Management Parameters

Optical parameters include laser wavelength, objective lens numerical aperture, protective layer thickness and free working distance. Data management parameters include data rate, video format, HDTV play time and bit-rate scheme. Disk structure parameters are user data capacity, minimum channel bit length and track-to-track spacing. 

1.Optical Parameters

The process for exposing data marks on a recordable optical disk is shown in Fig, where an input stream of digital information is converted with an encoder and modulator into a drive signal for a laser source. The laser source emits an intense light beam that is directed and focused onto the surface by the objective lens. As the surface moves under the scanning spot, energy from the intense scan spot is absorbed, and a small, localized region heats up. The surface, under the influence of heat beyond a critical writing threshold, changes its reflective properties. Modulation of the intense light beam is synchronous with the drive signal, so a circular track of data marks is formed as the surface rotates. The scan spot is moved slightly as the surface rotates to allow another track to be written on new media during the next revolution.


Blu Ray Disc Seminar Report in Computer Science


High Definition Camcorder Archiving

As the market penetration of High Definition TV sets continues to grow, so does the demand of consumers to create their own HD recordings. With the advent of the first HD camcorders, consumers can now for the first time record their own home movies in a quality level unlike any before. As these camcorders are tape-based, consumers cannot benefit from the convenience and direct access features they are used to from the DVD players and recorders. Now, the Blu-ray Disc format, with its unprecedented storage capacity, allows for the HD video recorded with an HD camcorder to be seamlessly transferred to a Blu-ray Disc. When the HD content is stored on a Blu-ray Disc, it can be randomly accessed in a way comparable to DVD. Furthermore, the Blu-ray Disc can be edited, enhanced with interactive menus for an even increased user experience and the disc can be safely stored for many years, without the risk of tape wear.

Blu-ray Disc and HD-DVD

The HD-DVD format, originally called AOD or Advanced Optical Disc, is based on much of today's DVD principles and as a result, suffers from many of its limitations. The format does not provide as big of a technological step as Blu-ray Disc. For example, its pre-recorded capacities are only 15 GB for a single layer disc, or 30 GB for a double layer disc. Blu-ray Disc provides 67% more capacity per layer at 25 GB for a single layer and 50GB for a double layer disc.

Applications

1.High Definition Television Recording
2.High Definition Video Distribution
3.High Definition Camcorder Archiving

Conclusion

The BD represents a major advancement in capacity as well as data transfer rate. It would be an ideal choice for the secondary storage purposes. The semiconductor storage for secondary memory is large, consumes more power and is more expensive. HDTV video recording and reproducing would essentially require the large storage capacity and data transfer rates, as offered by the Blu-ray disc. The Blu-ray disc has a wide variety of applications and is the ultimate storage device that would lead to digital convergence, ultimately leading to the convergence of the PC and CE technologies.

2 comments:

nicee said...

more about blu ray disc

shan said...

more about ac performance of nanoelectronics needed.


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