DVD DRIVE

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DVD DRIVE

• By Shahad Minahi
• And
• Hanan Jaafar

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INTRODUCTION

• In this PowerPoint, you will learn what a DVD
  consists of, how a DVD player reads a disc (a DVD
  is remarkably similar to a CD -- it has just been
  designed to hold more data)
• Nearly every movie produced today is available
  on DVD, and many older movies are being moved to
  the DVD format.

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The Basics

• A DVD is very similar to a CD, but it has a much
  larger data capacity. A standard DVD holds about
  seven times more data than a CD does.
• This huge capacity means that a DVD has enough
  room to store a full- length, MPEG-2 encoded
  movie, as well as a lot of other information.

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• Here are the typical contents of a DVD movie
• Up to 133 minutes of high-resolution video, in
  letterbox or pan-and-scan format, with 720 dots
  of horizontal resolution (The video compression
  ratio is typically 401 using MPEG-2
  compression.)
• Soundtrack presented in up to eight languages
  using 5.1 channel Dolby digital surround sound
• Subtitles in up to 32 languages
• DVD can also be used to store almost eight hours
  of CD-quality music per side.

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DVD ADVANTAGES

• DVD picture quality is better.
• Many DVD movies have an on-screen index, where
  the creator of the DVD has labelled many of the
  significant parts of the movie, sometimes with a
  picture. With your remote, if you select the part
  of the movie you want to view.
• DVD players are compatible with audio CDs.
• DVD movies may have several soundtracks on them,
  and they may provide subtitles in different
  languages. Foreign movies may give you the choice
  between the version dubbed into your language, or
  the original soundtrack with subtitles in your
  language.

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Storing Data on a DVD

• DVDs are of the same diameter and thickness as
  CDs.
• Like a CD, the data on a DVD is encoded in the
  form of small pits and bumps in the track of the
  disc.
• A DVD is made of some layers of plastic,
  totalling about 1.2 millimetres thick. Each layer
  is created by injection molding polycarbonate
  plastic.
• This process forms a disc that has microscopic
  bumps arranged as a single, continuous and
  extremely long spiral track of data.

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• You will often read about "pits" on a DVD instead
  of bumps. They appear as pits on the aluminium
  side, but on the side that the laser reads from,
  they are bumps.

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DATA STORAGEDVD VS CD

• DVDs can store more data than CDs for a few
  reasons
• Less Overhead, More AreaOn a CD, there is a
  lot of extra information encoded on the disc to
  allow for error correction
• . The error correction scheme that a CD uses is
  quite old and useless compared to the method used
  on DVDs.
• The DVD format doesn't waste as much space on
  error correction, enabling it to store much more
  information.

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• Multi-Layer StorageTo increase the storage
  capacity even more, a DVD can have up to four
  layers, two on each side. Here is a list of the
  capacities of different forms of DVDs

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THE DVD VIDEO FORMAT

• Even though its storage capacity is huge, the
  uncompressed video data of a full-length movie
  would never fit on a DVD. In order to fit a movie
  on a DVD, you need video compression.

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DVD AUDIO

• DVD audio discs and players are quite rare right
  now, but they will become more common, and the
  difference in sound quality should be obvious.
• DVD audio recordings can provide far better sound
  quality than CDs.
• CDs can hold 74 minutes of music. DVD audio discs
  can hold 74 minutes of music at their highest
  quality level.
• By lowering either the sampling rate or the
  accuracy, DVDs can be made to hold more music. A
  DVD audio disc can store up to two hours of
  6-channel, better than CD quality.
• Lower the condition further, and a DVD audio disc
  can hold almost seven hours of CD-quality audio.

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• In an audio CD or DVD, each bit represents a
  digital command telling the DAC what voltage
  level to output.
• Comparison of a raw audio signal to the CD audio
  and DVD audio output
• The graph above shows how the highest quality DVD
  audio compares to CD audio. You can see that DVD
  follows the signal more closely, but it's still a
  long way from perfect

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The DVD Player

• The Sony PlayStation 2 was the first video game
  system able to play DVDs.
• A DVD player is very similar to a CD player. It
  has a laser assembly that shines the laser beam
  onto the surface of the disc to read the pattern
  of bumps.
• The DVD player decodes the MPEG-2 encoded movie,
  turning it into a standard composite video signal
  .

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INSIDE A DVD DRIVE

• The DVD player has the job of finding and reading
  the data stored as bumps on the DVD. The drive
  consists of three fundamental components
• A drive motor to spin the disc .
• A laser and a lens system to focus in on the
  bumps and read them - The light from this laser
  has a smaller wavelength than the light from the
  laser in a CD.
• A tracking mechanism that can move the laser
  assembly so the laser beam can follow the spiral
  track.

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READING A DVD

• The hardest part of reading a DVD is keeping the
  laser beam centred on the data track. This
  centring is the job of the tracking system. As
  the DVD is played, the tracking system has to
  move the laser continually outward.
• A DVD has a second layer, the start of that
  layer's data track can be at the outside of the
  disc instead of the inside. This allows the
  player to change quickly from one layer to the
  next, without a delay in data output, because it
  doesn't have to move the laser back to the centre
  of the disc to read the next layer.

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Features

• Supported Formats
• DVD moviesJust about all players play DVD
  movies.
• Music CDs Most players also play music CDs.
• Video CDs Some players can handle this format,
  which is used mostly for music videos and some
  movies from foreign countries.
• CD-Rs Some players can play content that you
  create on your own computer.
• Audio DVDs A few players can handle this format
  for high-quality audio.

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OTHER FEATURES

• Dolby Digital decoderThis feature allows the DVD
  player to decode the Dolby Digital information
  from a DVD and convert it to six separate analog
  channels.
• DTS decoderThis feature allows the DVD player to
  decode the DTS information from a DVD and convert
  it to six separate analog channels .
• DTS compatibleAll DVD players are DTS
  compatible. They pass the digital audio
  information on to the receiver, which then
  decodes it.

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• Disc capacitySome DVD players can hold three,
  five or even several hundred discs.
• 96kHz/24-bit DACThis is the speed and accuracy
  of the digital-to-analog converter (DAC), which
  converts the audio information into an analog
  signal. Most movie soundtracks are encoded in
  this format.
• 192kHz/24-bit DACThis is an upcoming format for
  audio-only DVDs that are recorded at speeds of up
  to 192kHz and 24-bits. Only the newest DVD audio
  players have this feature.

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• Remote-control typeDVD players may come with
  three types of remotes
• A dedicated remote, which only runs the DVD
  player
• A multibrand remote, which can control other
  components, like VCRs and TVs made by other
  manufacturers.
• A learning remote, which can learn the signals
  from other remotes and assign them to a button.

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• THANK YOU FOR YOUR TIME AND ATTENTION WE HOPE YOU
  ENJOYED OUR POWERPOINT SHOW AND LEARNT A FEW
  THINGS ??