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Jargon Buster: Widescreen TV Explained
"Widescreen" is the term used to describe the new picture format (to television broadcasts) which is a key part of digital television. Otherwise called 16 x 9, widescreen is a more natural view for the human using both eyes. Imagine covering one eye - the resulting "shape" of the image as seen by the brain is square i.e. similar to that displayed on a 4 x 3 television. If you now imagine moving the palms of your hands vertically and horizontally towards the side of your face until you can just see them, then a 16 x 9 field of view is apparent. Incidentally, 4 x 3 and 16 x 9 refer to the ratio of the picture width to the picture height.

A widescreen TV set has the correct screen shape for Digital widescreen broadcasts, for enhanced enjoyment of your favourite programmes. Only Digital television offers true widescreen.
Viewing a 16 x 9 image on a 4 x 3 screen
Original 16 x 9 image
   The set top boxes have a set-up menu which allows the viewer to tell the box the shape of the TV screen being used to display digital programmes. You can then tell the box how you would like to view a 16 x 9 image - either letterbox or centre cut out.

The remote handset will then allow you to switch between the default setting and the other depending on how you want to view a particular programme. Additionally the broadcasters are transmitting signals to tell the set top box (or integrated TV) what format of programme is being broadcast.

"What information is lost if I fill my screen with centre cut out view of a 16 x 9 programme?" The broadcasters are using a 4 x 3 active picture area, so you only lose the extra peripheral information that fills the 16 x 9 scene.

Sport is a good example of this - some rugby matches are shot and broadcast in 16 x 9, the widescreen viewer sees the main action with lots of extra information such as other players near the featured scrum. The 4 x 3 analogue viewer or the digital viewer using centre cut out sees the main action - the scrum - as normal.
 
Centre cut out
  
 
Letter Box
  
 
Viewing a 4 x 3 image on a 16 x 9 screen
Original 4 x 3 image   Conversely, a widescreen set has to know how you want to display a 4 x 3 image - zoomed or pillarbox and will revert to a full width display when told that a 16 x 9 image is being sent. Manufacturers call zoomed by a variety of names - Panorama, Cinema, Zoom, Stretch and so on. The intention is to expand the active 4 x 3 picture area to fill a widescreen display. Unfortunately either some of the image is lost top and bottom of the screen or some distortion is introduced as the width is expanded to fill the screen without changing the height.

 
Zoomed
  
 
Pillar Box
  4 x 3 image displayed on a 16 x 9 screen with black 'pillar boxes' each side.
Stretched
  Image stretched to fit the screen with horizontal distortion of the image since the height remains the same as the original 4x3 picture.
It's important to get the right combination of display format and the format of the transmitted programme otherwise you end up with tall thin or short fat images in place of the correctly balanced picture!

Only Digital TV offers true widescreen pictures. On analogue TV you don't normally see the whole widescreen picture, and your widescreen TV has to stretch the picture to fit the screen. Digital widescreen pictures are the right shape for your widescreen TV. Adding a set top box will allow you full enjoyment of your favourite programmes in true widescreen and give you more Free-to-view services.

 
 
 
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