What is High Definition TV (HDTV)?

HDTV is a new digital TV system which displays high quality pictures with up to five times the resolution of the conventional TV broadcasts or DVD (Digital Versatile Disc) videos. It is becoming popular worldwide as broadcasters commence their HDTV programme services and large screen TV sets are widely available in the market at affordable prices.

HDTV Vs SDTV Vs Analogue TV

A picture on the TV screen is formed by a large number of small dots called pixels. The higher the number of pixels, the better the picture quality will be. The pictures of conventional analogue TV broadcasting provide a maximum of 720 (horizontal) x 576 (vertical) pixels. Typically the pictures of HDTV broadcasting provide a resolution of at least 1024 horizontal pixels and 720 vertical pixels and hence they have a better picture quality than those of analogue TV broadcasting. HDTV pictures are usually displayed on a wide screen (aspect ratio 16:9, i.e., the ratio of picture width to height) format, instead of the usual square screen (aspect ratio 4:3) format of conventional analogue TV pictures. Together with the ability to support multi-channel sound system, HDTV broadcasting enables viewers at home to have the same experience as watching a movie in a cinema.

Standard definition TV (SDTV) broadcasting can be considered as the digitized version of the conventional analogue TV broadcasting, both of which have the same screen format and picture resolution. However, SDTV pictures are free from "ghosting" and "snowing", which are commonly found in analogue TV pictures.

SDTV and HDTV are two of the main features supported by digital TV.