The aspect ratio for HDTV is 16:9 or 1.78:1. This means that for every 16 inches of horizontal screen, there are 9 inches of vertical screen, compared to the much squarer analogue TV ratio of 4:3 or 1.33:1.  Movies shown in the cinema are filmed in a variety of large screen ratios, but the most common is Panavision 2.35:1.  When these movies are shown on TV or VHS tape they do not appear the way they were shown in the cinema.  This is because the TV aspect ratio is smaller than the ratios in the cinema.  Digital Television has a ratio of 1.78:1 or 16:9 as it is commonly known.  This ratio was chosen to be the best compromise to show Widescreen movies on television. The 16:9 ratio provides a Widescreen view that nearly matches our natural peripheral viewing range.  See Aspect ratio

Anamorphic is the process used to film widescreen television programmes on a 4X3 frame, like Cinemascope and Panavision, widescreen television uses an anamorphic lens to squeeze the image vertically by 25% as apposed to 35mm panavision which has a horizontal squeeze. See Anamorphic Page

Original 4X3 Anamorphic Image	16x9 TV Screen

Pillarbox is a method used to display a 4X3 image on a widescreen television, this is achieved by using an Aspect Ratio Converter or "ARC" to squeeze the image horizontally by 25%, a Non Linier Editor such as Avid, Media100 and Premiere can also be used.

Original 4X3 Image	Pillarbox Transmission	16x9 TV Screen

A trend has been developing in the UK called 14:9, it simply means loosing the sides of a 16:9 image when displayed on a 4:3 television with small black bands top and bottom.

Original 4X3 Anamorphic Image	14x9 Letterbox	16x9 Letterbox

Original 4X3 Anamorphic Image	Letterbox Version	Centre Cut on 4X3 TV