What is the difference between HD-DVD and DVD?
The basic idea behind the HD-DVD is really simple — it looks like a DVD and acts like a DVD, but it holds more information. A DVD holds about two hours of standard definition video, but an HD-DVD can hold about 48 hours. A DVD stores information as a series of microscopic pits arranged in a very long spiral. A red laser reads these pits from the other side, so it sees them as bumps. The bumps reflect the laser’s light to a sensor. Electronics within the DVD player read the information from the sensor as a digital signal.
