Thursday, January 24, 2008


CD and DVD as data storage and delivery media, lasted successfully for decades and seems to be alive and kicking .As we speak, a new format war has begun. This time over the future of in-home media. On one side is HD-DVD, a format created by Toshiba and NEC; on the other side is Blu-Ray, created by Sony, Matsushita, and Philips. In a few years, blue laser drives will take over the role of DVD drives. The problem is that there are two competing technologies that will use blue lasers: HD-DVD and Blu-ray. Only one technology will eventually become dominant in the data storage market

What are HD DVD and Blu-Ray Disc?

Today's DVDs can hold 4.7GB of information, but many want a higher-capacity successor to accommodate the larger data demands of high-quality video. HD DVD and Blu-ray both use blue lasers to read and write data. this is because blue has a shorter wavelength than the red used in DVD and CD lasers, information can be packed more densely on a disc and a single disc can hold more.

The potential capacity of Blu-Ray discs cannot be expressed in words. A single-layer disc can hold between 23 and 27 gigabytes of data, enough for four hours of high-definition video; a dual-layer disc can hold between 46 and 54GB, easily enough for eight full hours of high-definition programming. Furthermore, since the layers on a Blu-Ray disc are so thin, there is potential for multi-layer discs with up to eight layers holding upwards of 200GB.

HD-DVD discs, promise a single-layer capacity of 15 gigabytes, or over three times that of single-layer DVDs. This means that discs can have information more tightly packed on the disc, enabling far greater storage capacity on the same size disc. Dual-layer discs are capable of holding 30GB, and Toshiba has announced a prototype three-layer disc with a capacity of 45GB. These discs are capable of holding between two and five hours of high-definition video with audio track.


The picture quality on both versions is 100% identical. They're using the same compression codec. Probably the exact same files on both discs.

The sound is better on the HD-DVD. It comes with Dolby TruHD sound, which is completely uncompressed audio. The Blu-Ray version has standard Dolby Digital sound.Also, the HD-DVD (And most WB HD-DVD's these days) comes with the regular DVD version of the movie on the other side of the disc. The Blu-Ray version doesn't.

The main difference between the both is the differing track pitch of the Blu-ray disc makes its pickup apertures differ, however—0.65 for HD DVD vs. 0.85 for Blu-ray—thus also making the two pickups technically incompatible despite using lasers of the same type.

Why Blu-Ray will be more expensive initially Blu-ray discs can hold more data than HD-DVD because the track on which the data is written is tighter, requiring the data layer of the disc to be closer to the surface. The data layer on a Blu-ray disc is 0.1mm from the surface, compared with 0.6mm for HD-DVD and traditional DVDs. It is because of this difference in disc thickness that Blu-ray will initially be more expensive. HD-DVDs can be produced by the same facilities as traditional DVDs with very little modification. Blu-Ray, on the other hand, will initially require expensive retooling or replacement of these production facilities.


The situation as it stands today is complicated. On one hand we have the HD-DVD format, which holds less data, but is cheaper to produce. On the other hand is Blu-Ray, with the potential for exponentially more capacity and durability, but with a significant manufacturer cost increase. Both players will offer features to ease the transition to HD, such as backwards-compatibility with standard CD and DVD media.

Well, as far as HD DVD vs. Blu-ray goes, it looks like we've pretty much passed the point of no return now; with each passing day it seems less and less likely that a compromise will be reached on a next-generation format.


1.Adopt HD-DVD. The initial costs of HD-DVD are lower than Blu-Ray since the technology is not radically different from current DVD technology.

2.Adpot Blu-Ray. The initial cost of Blu-Ray is higher than that of HD-DVD, but Blu-ray offers higher storage capacity and higher data-transfer rates. These properties make it more likely that Blu-ray will eventually be the prevailing standard for optical disc storage.


No one knows what the outcome of this format war will be – it all depends on which format consumers can get more cheaply, more quickly, with more movies available for it. Blu-Ray is technologically superior, true,but it is not always true that technologically superior products always win.Hence it is the survival of the fittest,which ever product attracts people will survive.

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