What is High Definition?
HD or high definition is a development in digital television which provides a higher resolution than standard broadcast pictures. HD broadcasts give very clear, vibrant colours with up to five times the detail of normal TV. To experience the ultimate viewing experience on your HD ready LCD or plasma screen you will require an HD receiver.
High definition in detail
High definition has dedicated production methods, specific transmission paths and specialised receivers. You can't watch HD TV on an old television; you need to have the right programming with the right connections and the right equipment. And that includes an HD ready TV and an HD receiver, like the Sky+HD box.
Apart from the clarity of high definition, digital TV can be tailored for use on the tiny screen of a mobile phone or a massive public display. It can be received through terrestrial transmitters, satellite dishes, cables under the street, cellular phones, through wired and wireless media to desk-tops and hand-helds, computers and iPods and even direct to storage devices with no human intervention.
How high definition works
When looking at a colour TV screen closely through a strong magnifier, it can be seen to be made up of groups of tiny red, green and blue dots called sub pixels. It doesn't matter if the TV is showing analogue or digital, the pictures are always made up of these little pixels. Digital television is simply the transmission of the brightness and colour values of the pixels, plus the soundtrack, as number data. The values are converted back into pixels, and hence pictures, at the receiver end of the transmission path.
It's the difference in the number of pixels that makes the contrast in clarity:
Standard definition digital TV displays a picture consisting of 720 by 576 pixels. This means the screen is made up of slightly less than half a million points of light.
High definition can display a picture of 1920 by 1080 pixels - well over 2 million - which adds clarity to scenes never before possible with either the old analogue system or standard definition digital.
High definition versus standard definition
With up to five times better picture quality than standard definition and increased colour vibrancy, it's easy to immediately see the benefit that high definition brings to your viewing. When mixed with Dolby Digital surround sound, you'll be able to have a cinema experience in your own home.