It's interesting how digital terrestrial television – the subject of our lead article this month – has taken off after being such a flop when it started.
I was out of the country at the time, but from what I heard Britain was a world leader in the field. The business model, however, was evidently faulty. But the phoenix that arose from the ashes of ITV Digital a few years ago has gone on to become a major force pushing the UK forward into an all-digital television future.
The challenge with digital television, though, is one of quantity versus quality. Today's digital media in the UK offer what is generally labelled "Standard Definition Television" (SDTV).
That means 625 lines or so, and although we have widescreen capability, it is simply anamorphic (ie squashed by the broadcaster and stretched by your set): no more data is sent than for a conventional 4:3 digital picture. But there is also High Definition Television (HDTV), which is by its nature has a 16:9 aspect ratio. There's only one source of HD in Europe at present, while the US has 40.
These are generally limited to 1080i (1080 lines, interlaced), a system that was really designed for CRT-based displays, or 720p (720 lines and 'progressive scan' like a computer monitor): modern flat-screen sets can do much better.
720p is great for fast motion (read 'Sports') while 1080i gives a higher static image quality that's lovely for landscapes and where there is little movement. The coming thing is 1080p that, as the designation suggests, gives the best of both worlds and is already offered in some home theatre systems.
The higher the resolution, the more bandwidth required. Digital terrestrial, cable and satellite can get several digital SDTV channels into the space of one analogue, giving us the technical ability to provide loads of channels with next to nothing on them.
Instead, we could have a smaller number of hi-def channels – not just movies – while having enough channels to retain plenty of diversity (not that a plethora of look-alike channels of crap really counts as 'diversity'). Fewer channels would mean higher ratings and thus channels easier to sell to advertisers, instead of the current fragmented marketplace, where it's hard to know what media to buy.
Sky is introducing HDTV soon, and you can expect to see it used first for sports OBs (though paradoxically these seem to be some of the last to go widescreen). Plans for hi-def DTT have not been announced, and doubtless we'll need the analogue switch off to happen before it can become a reality.
But whether broadcasters will be prepared to give us some quality instead of mere quantity remains to be seen. After all, if you look at the poor quality of a lot of digital broadcasts, and especially the atrocious lack of proper audio/video synchronisation these days (have they all forgotten about timecode?) it seems a little unlikely that broadcasters will either want to offer higher quality – or that they actually can.
