Digital audio and video
OK, before I begin, let me say that I think digital technology is great in principle. But I don't think that its implementation is so good.

For my money, CDs sound much better than records, pound for pound. OK, if you get a good turntable and well pressed, new vinyl playing through a top end system it will sound better than the equivalent CD through a £50 Argos boombox. But that's not my point. CDs use no data compression on their digitised audio, so the sound produced is down to the A-D and D-A converters and analogue signal chain.

Digital radio and television, on the other hand, relies on lossy compression algorithms in order to shrink the data stream to something which can be transmitted in the available bandwidth. Modern algorithms, MP3, AAC+, H.264 and so on are pretty good. But only if they're used at a decent bitrate. Digital radio (DAB) is crap. It uses an outdated algorithm, MP2, which only sounds anything like as good as FM at bitrates of above 192kbps or so. But only Radio 3 uses 192kbps, and then only for part of the time. Most stereo stations use 128kpbs, and Ofcom has now permitted them to drop this even lower. So DAB sounds awful.

It's marketed for its crystal clear reception. This is true, inasmuch as there is no hiss on the signal. But personally, I find a little background hiss much less offensive to my ears than the digital burbling and lack of stereo image that DAB produces.

And so to television. LCD tellies and digital signals are the thing these days. But look carefully at your Freeview/Sky picture on your fancy flat panel screen. See those little blocks in the image? The way that football pitches seem to move independently of the action? The little fuzzy blurs round fast moving objects?

They're all due to digital compression. Now, a good High Definition signal displayed on a modern screen at 1:1 pixel ratio is pretty good. But watch one of these useless shopping channels, and see how poor the picture is. It's like watching through a net curtain.

Another issue is pixel scaling. A standard definition digital video signal is 768 x 576 pixels. Most HD LCD screens comprise 1366 x 768 pixels and full HD ones are 1920 x 1080. A standard definition signal will be upscaled to fill these screens, but will do it using a non-integer multiple. So the digital image is being manipulated in order to make it fit the screen, but no more information is visible on an HD screen than an SD one, and in fact an SD signal will look better on an SD display than an HD one.

Old fashioned CRT televisions actually do a better job at upscaling, as even though they have a fixed number of pixels, the analogue nature of the signals driving the electron guns makes a better job at 'smearing' the image and produces a smoother result.

So don't believe the hype about digital. Just because it is digital doesn't mean it's better. In fact, at the moment, with the current bitrates allowed and used in the broadcasting industry, you'd be well advised to stick with an analogue signal and CRT television for as long as possible, so long as you get good reception. Unless of course you have a hankering for 'choice' and really want 1000 television channels showing (for the most part) infomercials, repeats of old films, football from the South Korean 4th division and porn*.

Sorry for length, which is reaching PJM proportions. Well, not quite.

_{*Actually, the porn is OK}
( K2k6 has a proper job these days, Fri 2 May 2008, 19:35, 1 reply)

Urgh
It did my head in when DAB was introduced and they were waffling on about "It's digital, so it's CD quality". Bollocks, if you compress the hell out of it you end up with crap. What, is that a round of applause I hear? Funny, the compressed digital version sounds like someone pissing on a thousand tiny wind chimes. Wankers.
( SteamedCleaner, Sat 3 May 2008, 17:46, closed)