Charles Arthur: The Geek

The high price of changing how we watch TV
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The Independent Online

Certainly, HDTV - already winning fans in the US and Japan - should make a big difference to the way television pictures look. Yet that difference isn't what you might think. True, there's more of it: each frame has about four times as many pixels as standard screens. It's like DVD-quality TV, only better.

But HD pictures don't zero in on the dust on a character's nose. Instead, they show more of what's happening in the rest of the picture, to "widen the visual field". That's why HDTV sets are wider; it's the way we see the world, with our visual field extending for about 180 degrees. The picture is also refreshed faster, so there's less flicker. Overall, it's just nicer. But HDTV also demands either far greater bandwidth, or new compression software to take the digital signal, squeeze it down a narrow link and then expand it at the other end.

There's also the problem of compatibility. And wow, what a problem. If you've got a Freeview set-top box to watch the existing digital TV signal, you'll need a new HDTV-compatible one, once any of the Freeview broadcasters start (none has announced plans). If you record an HDTV programme on your existing VHS, DVD or hard drive recorder, it'll just play back at normal "low-fi". And if you have Sky, you'll need to buy a new HDTV set-top box in 2006. So this is going to cost you, all over again. And don't forget to look for a sticker saying "HD Ready" on anything you buy with this in mind.

BSkyB will no doubt tempt people with plentiful content. The BBC, however, has to justify putting out HD shows. Although quite a few programmes are shot in HD, they leave the editing suites "mixed down" to sub-HD format. For BBC bosses, the dilemma is: should they spend money creating and marketing an HD channel, or just have occasional HD-format programmes?

Outside broadcasts are the most likely first output from the BBC, as those will demonstrate HD while being significantly cheaper to make. Gardening shows would be ideal to show off HD's vivid colours. After that, sports events such as Wimbledon are naturals.

BSkyB and Telewest will issue upgraded PVRs capable of recording the HD signals and playing them back faithfully. And it's these that carry the most interesting extras. They're likely to have sockets so you can link them to a broadband connection, for super-fast interactive TV. What if your computer tells your TV what to watch? Or vice versa? That may be the real fruits of HDTV: any show, anywhere, via any medium. But most people are only just getting used to the idea of digital TV. When they hear they've got to replace their whole set-up... well, it's a tough sell.