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DVD Demystified

DVD Demystified

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364<br />

provide better-than-CD audio. The extra audio tracks can be used for foreign<br />

language, commentary, additional music, and more.<br />

Video. The video quality of VHS tape is much lower than broadcast or<br />

cable signals. Tape dropouts (poor or missing magnetic particles) cause dots<br />

and small flashes in the picture. Wear and stretching from kids playing<br />

their favorite tape twice a day cause the picture to degrade quickly, not to<br />

mention requiring more frequent head cleanings. Head alignment differences<br />

cause tracking problems and additional loss of quality. <strong>DVD</strong> digital<br />

video, even though it is compressed, can look almost as good as studio masters.<br />

Discs never wear out from repeated playing; servo-controlled laser<br />

tracking keeps everything in perfect alignment; and error-correction codes<br />

compensate for defects and damage.<br />

Prerecorded videotapes are copied in high-speed duplicating machines;<br />

they do not nearly match the quality of the duplication master. <strong>DVD</strong>s are<br />

stamped into plastic using metal plates; they contain virtually the same<br />

data as the master.<br />

Each generation of a videotape copy loses quality. A digital copy of a <strong>DVD</strong><br />

is a perfect replica, no matter how many generations it is removed from the<br />

original. Of course, this assumes that the original copy is not protected.<br />

Copies of home videos sent to Grandma will no longer be so blurry that she<br />

cannot tell the grandkids apart.<br />

Price. Discs are cheaper than tapes and can be mass-produced faster and<br />

more easily. Whether this savings ever gets passed on to the consumer<br />

remains questionable, since it never seemed to happen with CDs. Some<br />

movie studio executives have stated that they plan to make <strong>DVD</strong>s as cheap<br />

or cheaper than videotape, especially older movies that have already made<br />

back their original cost.<br />

Subtitles. When subtitles are included on a videotape, they must be<br />

added permanently to the video picture. <strong>DVD</strong> allows up to 32 different subtitles<br />

or graphic overlays that can be turned on or off at will.<br />

Advantages of Videotape over <strong>DVD</strong>-Video<br />

Chapter 8<br />

Recordable. Recordable <strong>DVD</strong>-Video will not be available in the home<br />

before the year 2001. Recordable <strong>DVD</strong>-Video technology will have to<br />

improve significantly and become much cheaper before it will become wide-

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