High definition television, or HDTV, uses digital technology to deliver a sharper, more realistic image, one that makes ordinary television pictures look soft and fuzzy. HDTV shows are broadcast in widescreen format, are often coupled with a Dolby Digital 5.1 soundtrack and, because they are transmitted digitally, never suffer from ghosting or snow like many analog broadcasts.
Together, the true-to-life images and surround sound of HDTV create an experience that is akin to having a commercial cinema in your own living room. Sport, wildlife documentaries and movies, in particular, look fantastic in high definition. And high definition is made for viewing on a large screen; in fact the bigger the better.
Why HDTV now?
In the same way that mobile phone services switched from analog to digital, television, too, is making the change. The transition commenced in 2001, and everything currently broadcast in analog is also being broadcast in digital. The complete switchover to digital is scheduled for 2012, so eventually all television in Australia will be digital. In short, digital TV (DTV) is the way of the future, and HDTV is a major feature of digital TV.
Digital TV comes in two flavours: standard definition (SD) and high definition (HD). While high definition offers superb-quality pictures and surround sound, SD improves on traditional television too, with better reception, widescreen DVD-quality pictures and CD-quality sound. It also offers a swag of other enhancements, including:
- Electronic Program Guide (EPG)
An onscreen guide to programming for the coming week, for those stations that transmit this information
- More channels
SBS and ABC each provide two digital TV channels, the secondary channels broadcasting time-shifted programming from the main free-to-air channel, with up to 30 specialist channels possible from new broadcasters from 2008.
- Closed captioning
Subtitling of programs for the hearing impaired
The ability to switch between different camera angles, and display additional video and text information (eg. player statistics, recipes, gardening tips) relating to a program
Channels broadcasting non-traditional audio, video and text-based programs, including parliamentary proceedings, weather and surf reports, and infomercials, are likely to appear in the future
In the future, interactive TV (iTV) will allow you to interact with what you see, enabling you to, among other things, participate in quiz shows, do the shopping and the banking, hire movies and play games without leaving the sofa. Some programming already includes an interactive component that you can access through your remote control.
Digital vs analog
With an analog transmission, TV signal quality degrades the further away you are from the transmitter. Even the weather and geography interferes with the quality of picture you receive from an analog transmission.
A digital TV signal, however, produces sharp, clear pictures, regardless of these factors, up to a point. Provided you have good-quality equipment, with a half decent signal, a digital TV show should look the same on your set at home as it did in the studio. But if the signal falls below a certain strength, you lose it completely. There’s no snow or fuzz as you’d see with a weak analog signal, it?s either all or nothing. This is called the ‘cliff effect’.