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HOW TO CARE AND CLEANING DVD
DVD are read the data by laser, so DVD are should be avoid from dust, fingerprints,
scratches and smudges. If that resistant stand at DVD, it could make the data
errors. On a video player, the effect of data errors ranges from minor video
artifacts to frame skipping to complete unplayability. So it's a good idea to
take care of your discs. In general treat them the same way as you would a CD.
Your player can't be harmed by a scratched or dirty disc unless globs of nasty
substances on it actually hit the lens. Still, it's best to keep your discs
clean, which will also keep the inside of your player clean. Don't attempt to
play a cracked disc, as it could shatter and damage the player. It doesn't hurt
to leave the disc in the player, even if it's paused and still spinning, but
leaving it running unattended for days on end might not be a good idea.
In general, there's no need to clean the lens on your player, since the air
moved by the rotating disc keeps it clean. However, if you use a lens cleaning
disc in your CD player, you may want to do the same with your DVD player. It's
advisable to use a cleaning disc specifically designed for DVD players, because
there are minor differences in lens positioning between DVD and CD players.
Periodic alignment of the pickup head is not necessary. Sometimes the laser
can drift out of alignment, especially after rough handling of the player, but
this is not a regular maintenance item.
What happens if I scratch the disc?
Scratches may cause minor data errors that are easily corrected. That is, data
is stored on DVDs using powerful error correction techniques that can recover
from even large scratches with no loss of data. A common misperception is that
a scratch will be worse on a DVD than on a CD because of higher storage density
and because video is heavily compressed. DVD data density (say that fast ten
times!) is physically four times that of CD-ROM, so it's true that a scratch
will affect more data. But DVD error correction is at least ten times better
than CD-ROM error correction and more than makes up for the density increase.
It's also important to realize that MPEG-2 and Dolby Digital compression are
partly based on removal or reduction of imperceptible information, so decompression
doesn't expand the data as much as might be assumed. Major scratches may cause
uncorrectable errors that will produce an I/O error on a computer or show up
as a momentary glitch in DVD-Video picture. Paradoxically, sometimes the smallest
scratches can cause the worst errors (because of the particular orientation
and refraction of the scratch). There are many schemes for concealing errors
in MPEG video, which may be used in future players. (by Jim Taylor / videodiscovery.com)
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