Australian TV stations started broadcasting a digital television signal on January 1st 2001, in addition to the existing analog system.

It began with a whimper rather than a bang, with no equipment available for sale and almost no high definition programming (HDTV) planned at that time.

Things have improved somewhat since then, with the stores carrying a fair range of widescreen (16x9) TV's, alongside the increasingly obselete 4x3 sets. Although some of these sets still require a set-top box to receive digital signals, we are beginning to see many sets with inbuilt digital receivers.

All the networks now simulcast all programming in both digital and analogue. The commercial networks, however, still continue to be frustrated by laws (designed to protect the pay-tv industry) which prohibit them from multi-channel broadcasting.

The public broadcasters, however, are unhindered by such restraints. The ABC uses muti-channelling to transmit ABC-2.

SBS also uses multi-channelling to transmit SBS-2.

The analogue network was originally due to be turned off by 2008, but this has been postponed to at least 2010, and may be extended beyond that.

All of the networks now transmit some high-definitiion programming (HDTV), although the method and quantity varies. One of the first local dramas to go HD was Channel Nine's McLeod's Daughters, which has been transmitted in HD for several years. Because it is originated on 16mm film the picture quality in HD is still fairly ordinary, although it does make the film grain much clearer. It also goes out with 5.1 sound - something which is still fairly rare for a domestic free-to-air programme, although it is more common in movies, particularly on pay-tv.

An increasing number of imported programs fom the US and the UK are in HD, although not often with 5.1 sound.

The Australian television industry has adopted both Dolby Digital (AC-3) and MPEG audio as the preferred sound formats for Digital TV. Both use data compression to carry anything from mono up to 5.1 audio. The commercial channels and the ABC mostly use AC3, but SBS uses MPEG (which is why SBS sounds louder at home).

For those of us in the sound fraternity, digital television, even without 5.1, offers interesting possibilities - for one thing, the networks' ubiquitous transmission compression (you know, the boxes that squash our mixes beyond recognition in order to reduce the dynamic range to virtually nothing) is theoretically no longer required (was it ever?). Unfortunately it appears most networks still compress the audio on transmission in both digital and analogue, although probably not so much in 5.1.

There is, by the way, no reason for stations to compress audio on digital TV - they have always done this in analogue for technical/legal reasons, to avoid having the narrow sound notch impinge on the picture signal, causing unsightly "sound bars" on the picture. Stations could lose their licence for allowing this to happen. This is simply not an issue in digital - the normal dialogue level for AC-3 is -27dB, giving plenty of headroom for most progarmmes.

The preferred delivery format for 5.1 for television has so far been Dolby E (usually on Digital Betacam), but with new video tape formats having up to eight sound tracks, this may not always be the case.

© Philip Purcell 2007

How low can you go? The Kross set-top box - $79

A quick look around the shops shows that most retailers now carry a large range of digital TV's (both standard and high-def) and a variety of set-top boxes (STB's). The LCD vs Plasma battle still rages, with CRT sets becoming increasingly rare. Suprisingly, there are still some 4x3 sets being sold. Because the Australian standard for DTV is almost unique in the world, it took some time for manufacturers to take the plunge, but most of the major manufactures now have sets on the market. Many of the plasma and LCD monitors are capable of displaying high-definition, and an increasing number have a high-def receiver built in. Some set-top boxes have a hard drive (these are sometimes called PVR's - personal video recorders) allowing programs to be stored digitally for viewing later, or time-shifted (delayed viewing while still recording). Set-top boxes have plummeted in price, with supermarkets carrying some basic models for as low as $79! There still seems to be a lot of confusion about 16x9, with many shops displaying widescreen pictures on 4x3 monitors (featuring very tall, skinny people), and 4x3 pictures on widescreen monitors (with very short, fat people). Imagine how confused the customers are going to be about 5.1 sound!

LINKS: Digital TV in Australia LINKS :Department Of Communications LINKS: Australian Broadcasting Authority LINKS: Digital Broadcasting Australia