The DVD format has been hugely successful both as a home entertainment media and a computer storage format. But with the release of HDTV and ever increasing storage requirements for digital media, the need for a next generation storage format developed. Two competing formats have emerged, Blu-ray and HD-DVD. While both were developed with similar base technology, the two formats have a lot of technological and political differences. In this article, I intend to take a look at both Blu-ray and HD-DVD to give consumers an idea of what both have to offer.
The technology of the next generation DVD formats are both based upon the new blue-violet lasers. These have a beam width of 405 nanometers compared to the previous 650 nanometer red lasers used by both CD and DVD media. Because this beam is thinner, it allows more more data to be fit onto the disc. This is extremely important because the amount of data stored in a high definition video stream is much greater.
Broadcast high definition television streams have a required data bandwidth of 19.3 Mbps. Both formats have a minimum transfer rate of 36 Mbps that should provide them with sufficient data streams for quality higher than broadcast high definition. Of course, the resolution of the video and the encoding method will play various roles in the required signal bandwidth but it should be able to handle 1080p signals.

What's the Difference?
The major difference in the two formats comes from how the laser is used on the media and the media itself. The Blu-ray standard uses a lens that provides a tighter focus on the media surface. This allows the Blu-ray format to store 25GB on a single layer disc and 50GB on a double layer. The HD-DVD specification by contrast stores either 15GB of 30GB respectively.
The media is also very different between the two. The HD-DVD media was developed around existing techniques used in the production of DVD and CD discs. This allows the HD-DVD to have a lower overall cost than the Blu-ray media. On the other hand, Blu-ray specifications allow for additional layers on a single disc that can provide up to 200GB of total storage. TDK has already successfully produced this media but has not set any prices.

Conclusions
The current state of affairs over the next generation DVD formats is really a wait and see. The dominant format will eventually be born out by the consumer electronics market and not the computer market. It may be a year or so though before we have a clear winner. This will have strong implications for the storage market as the majority of optical drives are now used in the production of video discs and not data storage. Why choose one format now for a computer when the other format may win out?
if you want to use it for video only, you may pay no attention to the competition of these two formats. There has been so many file formats in the Internet, it’s unnoticeable to have two more. In the computer market, maybe they are only different file formats. Or no difference with the help of converters, such as XiliSoft video converter, Nokia Multimedia Converter etc. If however you are not concerned about using it for video and solely are using it for storage purposes, the Blu-ray format with its higher disc capacities is the clear choice. Of course, with the low cost of external hard drives, having backups of materials put onto an optical storage disc is becoming less and less common.

Hi friend! Thanks for your valuable information

(in reply to rummuny)

just cut and paste . i think its a efficenct way to learn some basic info when you surf in the net.

(in reply to alexmacris)

Just a few comments on the text.

What it also makes the Blu-Ray discs more efficient in terms of capacity is the different modulation technique it uses compared to the HD DVD.

In addition, the HD DVD specs also allow more layers to be added on the blank discs. The HD DVD camp had the advantage to apply the already succesful manufacturing techniques of the DVD-R DL media on the HD DVD, making development easier and less expensive. On the other hand, the advantage of the BD  is that it includes new promising  technologies  that could turn out to be more sufficient in the future.

(in reply to rummuny)

In fact, I think, that, apart from any existing specifications, in the case of a BD, being the recording surface closer to the laser permits more layers than in the DVD case.

TDK has already demonstrated a 4-layer 100GB BD and has promised to offer next year prototypes of double this capacity.

(in reply to Tony Veglis)

Is this so?
"The dominant format will eventually be born out by the consumer electronics market and not the computer market."
There are allready high definition samples and more http://www.microsoft.com/windows/windowsmedia/musicandvideo/hdvideo/HDVideo.aspx
and also devices that can directly stream a movie over the internet without using a computer.
So you will be able to record a movie to your dvd what ever rw ?

(in reply to sp)

but its not popular now to stream a movie over the internet without using a computer.

(in reply to adiadidas)

check the advert
up right
http://www.pandora.com/. Its not very expensive and u dont need a pc        

(in reply to rummuny)

I think whats important is that HD DVD camp hasn't, yet, shipped a fully working burner... media have been announced but where are the drives?? On the other hand, BR burners are way too expensive, so normal users cannot  use them, probably we will have to wait until prices drop for both drives and media... Maybe by that time, storage capacity has exploded to 50GB by BR, or even higher... PS3 is another factor, but if its build-in protection is "heavy" and no modchips hit the market, then not many chances for BR burners to become popular...

Only time will tell who will be the absolute winner.

(in reply to adiadidas)

the ratio of capacity to price is important.

(in reply to alexmacris)

check out these devices
http://www.cdrinfo.com/Sections/News/Details.aspx?NewsId=17881

(in reply to rummuny)