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The Technology of DVD Media

A Digital Video Disc or DVD is one of theProducing DVDs requires certain
most popular forms of storage media nowadays.authentication. Also, certain processes and
It is an optical disc and mainly used torules are needed to be followed to handle
store videos. However, data in any form cantheir production. Present day markets are
be stored on a DVD. The dimensions of a DVDfull of illegal and fake DVDs. Especially in
are generally the same as a common compactAsia, Africa and Brazil. So, certain security
disc but the amount of data that can bemeasures are applied to check this illegal
stored  is  six  times  greater.business. Copy prevention techniques are used
that prevents illegal replicating of the
The different variations of DVD are based onoriginal  disk.
the way data is being stored on it. A DVD-ROM
has pre-written data that can only be read. AA DVD-Video is standard for storage of video
DVD+R and DVD-R are the ones on which thecontent on the media. Typically the format in
data can be written only once; and on awhich video is stored in the DVDs is MPEG-2,
DVD+RW the data can be written and erased16:9 aspect ratio videos. The resolution used
more than once. The lasers used to read DVDsare 720*576 (PAL) or 720*480 (NTSC) at 25 or
are  typically  of  650  nm  wavelength.29.97 FPS. The audio on the disc is stored in
DTS (Digital Theatre System) or AC-3 (Dolby
The terms DVD-Audio and DVD-Video discs areDigital) formats. However, a number of other
DVDs with suitably structured and formattedresolutions and formats are also supported.
audio and video content respectively. OtherOther features like selectable language in
types  of  DVDs  are  called  DVD-data discs.subtitles, menus, multiple audio tracks and
more than one camera angle is also supported
The term `DVD` is used for an unofficial fullby  DVD-Video.
form `digital video disc`. However, it was
officially announced that it stands forThe DVD-Audio format is used to deliver
`digital  versatile  disc`.high-quality audio content. A number of
channel configuration choices (like from mono
A typical DVD has a 4.7 GB storage capacity.to 5.1 or 7.1 surround sound) at a number of
These discs are one sided and single layeredsampling frequencies are offered by the
i.e. the data is stored only on one side ofDVD-Audio. The higher storage capacities
the disc and only at one level. The size isenable it to store a considerable higher
enough for a high quality 133-minute movie.amount of music or a much higher audio
The double sided and dual layered DVDs canquality.
store about 17 GB of data in any form. The
capacity  dwarfs  a  compact  disc  easily.Although the DVD-Audio has higher technical
specifications, the debate on whether the
The writing speeds on a DVD vary from 1350 KBaudio enhancements that are being included
s (1 x) to 26 MB/s (18 x to 20 x). For a CD,are actually distinguishable or not in a
the  speed  1  x  means  only  153.6  KB/s.typical  listening  environment  is still on.
Initially, the burning or the duplication ofThere are a number of possible successors to
DVD was an expensive work and requiredthe DVD. The strongest being the Blu-Ray
skilled persons to do it. Today, the processDisc. Others are Maxell`s HVD (Holographic
of writing on a DVD has become a piece ofVersatile Disc) and the 3D optical storage
cake and any one with a little knowledge ofdiscs that are being developed actively.
computers can do it at a click of the mouse.



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