What is the difference between a HD-DVD and a Blueray?

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  • 1 decade ago
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    In Short: Blu-ray discs are more expensive, but hold more data - there, that's all.

    For full details read below:

    Philips's development of the Laserdisc in 1969 yielded many of the technologies Sony carried over and adopted when they partnered with Philips to create a little something called the CD way back in '79.

    Both companies were hard at work together once again in the early 1990s on a new high-density disc called the MultiMedia Compact Disc (MMCD—original name), but their format was eventually more or less abandoned in favor of Toshiba's competing Super Density Disc (SD), which had the vast majority of backers at the time, such as Hitachi, Matsushita (Panasonic), Mitsubishi, Pioneer, Thomson, and Time Warner.

    The two factions cut a deal, brokered by IBM president Lou Gerstner, on a new format: DVD. Toshiba wound up on top after the dust settled in 1995/1996, and Sony and Philips, who weren't cut in on the standard (and royalties) nearly as much as they'd have liked, immediately started work on a next gen system.

    The Professional Disc for DATA (aka PDD or ProDATA), which was based on an optical disc system Sony had already been developing in the side, would eventually become the Blu-ray disc. Toshiba, not to be outdone by the pair, also started work on a next gen system, the Advanced Optical Disc, which eventually evolved into the HD DVD.

    After thirty-five years of optical audio/video disc development we're back where we were 20 years ago: two money-grubbing factions fighting each other and threatening to wreak havoc on the consumer electronics industry. Apparently history really does repeat itself.

    Both systems use the same kind of 405nm wavelength blue-violet laser, but their optics differ in two ways. Since the Blu-ray disc has a tighter track pitch (the single thread of data that spirals from the inside of the disc all the way out-think grooves on a 12-inch vinyl single vs. an Elvis Costello full-length album), it can hold more pits (those microscopic 0s and 1s) on the same size disc as HD DVD even with a laser of the same wavelength.

    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. HD DVD discs also have a different surface layer (the clear plastic layer on the surface of the data - what you get fingerprints and scratches on) from Blu-ray discs. HD DVD use a 0.6 mm-thick surface layer, the same as DVD, while Blu-ray has a much smaller 0.1mm layer to help enable the laser to focus with that 0.85 aperture.

    Herein lies the issues associated with the higher cost of Blu-ray discs. This thinner surface layer is what makes the discs cost more; because Blu-ray discs do not share the same surface layer thickness of DVDs, costly production facilities must be modified or replaced in order to produce the discs. A special hard coating must also be applied to Blu-ray discs, so their surface is sufficiently resilient enough to protect the data a mere 0.1mm beneath - this also drives the cost up. The added benefit of keeping the data layer closer to the surface, however, is more room for extra layers.

    <note from me> Largely copied from source URL.

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  • 4 years ago

    The Blu-ray Disc and HD-DVD are the two competing extreme-definition DVD formats that are obtainable to shoppers. the two systems make the main of latest Blue Laser and video compression technologies to attain extreme definition video playback on the comparable length disc as a favourite DVD. in spite of the undeniable fact that, neither format is well suited with different. In different words, you won't be able to play a Blu-ray Disc in an HD-DVD participant, or vice versa. in spite of the undeniable fact that, LG is introducing a obtainable answer, what they have dubbed, "the comprehensive Multi-Blue Hybrid participant".

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  • In short, you're getting less capacity, but lower price with HD DVD. Higher capacity + higher price is Blu-ray. The quality of the picture/sound is going to be great on good transfers for either technology. The other issue right now, is some movies are only available on one or the other. In the end...I imagine we'll have players for both.

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  • Anonymous
    1 decade ago

    blue ray has better quality pictures and the new cds can hold more data

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