High Definition TV....Is It What it Says it Is?

I recently bought a new TV and found that traditional CRT TVs were very hard to find in my local electronics stores, other than small portables. They were almost exclusively stocking Plasma and LCD flat screen sets. Now I'm not going to deny that they are much prettier than CRT TVs, but I found the picture quality to be almost universally appalling. The pictures were very blurry and pixelled as well. On those rare occasions that there were CRT and LCD or plasma TVs side by side in the shop, a blind man could have seen that the CRT picture was far superior. One of the reasons for this is that flat panel TVs are designed to cope with the resolution of high definition (HD) TV, with standard definition (SD) pictures being zoomed to fill the screen. Quite often the TV doesn't do a particularly good job of this, making the picture look nasty (think of when you have a video clip on your PC and then go 'full screen' and the picture looks much worse). Therefore, the logical conclusion is that HD TVs are a bit of a mistake if you predominantly watch normal TV - which is of course what we will all be doing for quite a while to come - even Sky only have a handful of HD Channels among their lineup of hundreds of SD channels.

Another thing that I noticed is the bitrates of the broadcasts themselves. While I was TV shopping, I saw some pretty enormous HD TVs which were showing what appeared to be computer generated HD pictures. There's no denying that the picture quality was mind-boggling. It was quite flawless. So how come I have heard that people are generally not exactly blown away by the quality of their Sky HD pictures? This is because the quality of the picture you see is largely dictated by the bitrates of the channel.The bitrates is the amount of information which is sent to form the picture, per second. To (hopefully) illustrate this point, I've created two short clips - one with high bitrates (30 seconds to download) and one with low bitrates (10 seconds to download). Right click the files and save them on your desktop before opening. There's no sound, I chopped it out to reduce the file size. I hope you could tell the difference between the files! They have exactly the same resolution and frame rate, but one is less than a fifth of the size of the other. As you can see, the smaller file is much more blurry. However, your Free view aerial or Sky dish can only receive a certain amount of information at once, so the broadcaster would have the choice of either broadcasting one clear channel (like the big clip), five blurry channels (like the small clip), or something in the middle. The amount of information per channel can be fixed individually, which is why, say, BBC One looks a lot more clear than some of the crappy music and shopping channels.

Anyone who watches football on Sky Sports (I'm talking about normal SD television now, I can't speak personally for HD broadcasts) will know that the pitch turns into a gooey green mess whenever the camera moves, and 'catches up' when the camera stops. This is what happens when the amount of information per channel is too low. Sky could quite easily make the pitch look like a pitch again if they removed a few Box Office channels and shared the freed-up bandwidth between the sports channels, however this would reduce their revenue, so it will never happen. HD broadcasts suffer from exactly the same problems. Whilst HD television is technically capable of producing mind blowing levels of graphical detail, it will never do so as long as channel bitrates are set by commercial organizations. Hence I would speculate (and I'm open to debate on this) that a satellite or cable HD broadcast may well not look that much more impressive than SD channels on a traditional CRT TV.

This might all seem to like I am hating, but the whole SD v HD, CRT v LCD/plasma debate seems to be based on broadcasters and electronics manufacturers pushing products which costs a fortune and yet offer very little benefit in return.