According to a recent survey by the British Video Association, there are a lot of people out there who aren’t entirely clear about HD – what is it, what they need to watch it, and so on.
Rather than say “Gosh, aren’t people daft,” let’s look at the answers to those questions. First, to understand what High Definition (HD) is, you probably ought to know what it isn’t.
Standard Definition, or SD, is what you’ve been watching for years. And with digital TV in the UK, it means a picture made up of at most 576 dots or pixels (one per line) from top to bottom, and 720 left to right. The picture is drawn first with the odd lines, and then with the even lines, a technique called ‘interlace.’ I say “at most” because some channels use fewer pixels.
A picture is often described using a shorthand giving the number of lines, and a letter; standard definition is referred to as 576i, where the ‘I’ means ‘interlace.’ This is the sort of picture that almost everyone in the UK is watching at the moment.
High definition pictures that are broadcast in the UK on Freeview HD, Freesat, and Sky HD are usually 1080 dots from top to bottom, and 1920 left to right, again drawn first with the odd lines, and then the even lines; this is often referred to as 1080i.
A quick bit of maths reveals that that means there are five times as many dots in an HD picture as in an SD one, hence the ‘five times clearer’ boasts of HD. The other thing about HD in the UK, is that it’s often broadcast with high quality surround sound, whereas SD just comes with stereo.
If you have a Blu-Ray player, it can also create pictures in a format referred to as 1080p; the ‘p’ stands for “progressive” which means that instead of drawing first odd and then even lines, the whole picture is displayed in one go. This is about the best quality you’ll get, but it’s not yet practical to broadcast it. A third HD picture size is referred to as 720p – that’s 720 dots top to bottom, and 1280 left to right, displayed in one go. But it’s not used by any UK broadcasters right now, so you don’t need to worry about it too much.
So, with all those extra dots making up the picture, HD can provide a much clearer picture than SD – that’s better detail for football, or more realistic nature documentaries, and scarier aliens.
However, as the BVA survey showed, a lot of people don’t quite know what they need.
Is your TV set ready?
The first thing you need to watch HD is a television that can display an HD picture. Simple enough – just about every TV set you can buy these days is labelled ‘HD Ready.’ But this is where the confusion sets in.
HD Ready means just one thing. It means that the TV has a wide screen, made up of enough dots to show an HD picture, and a connection on the back that can be used to feed the HD picture into it. That’s it.
It does not mean that an ordinary picture watched on the set magically becomes HD; it doesn’t – it’s just magnified to fill the screen. And it doesn’t even mean that the set will pick up the new Freeview HD signals. All it means is that, if you have something that creates an HD picture, the TV can display it.
That ‘something’ might be a SkyHD box, a Blu-ray player, a games console, or a Freesat or FreeviewHD box. Without one of those, all you’re watching is an SD picture, through a magnifying glass – and we all know that look closely enough at something in a magnifier, and you can spot the flaws.
TVs usually have a label to show they’re ‘HD Ready’, and some have a label that says ‘HD Ready 1080p’ which means the screen has enough dots to show a 1080p picture, without having to shrink it to fit; without the ‘1080p’ bit, a set has to have at least 720 dots vertically to qualify for the label.
What about Freeview HD?
So you have a TV with built in Freeview, and it’s HD Ready. Doesn’t that mean you’re watching FreeviewHD?
No. FreeviewHD is a brand new system, and until early this year, there weren’t any TVs available that worked with the new technology involved. Some TVs may work with the HD services broadcast elsewhere in Europe, but not with FreeviewHD. These sets – like any other HD Ready set – won’t show the FreeviewHD programs on the guide, and when you watch existing Freeview channels (or Sky channels that aren’t in HD), they’ll still all be in standard definition, just made big enough to fit the screen.
The only way to tune into an HD broadcast is with an HD receiver; there’s a special logo for those, and there’s also a logo specifically for FreeviewHD, which guarantees the set will work with things like the BBC’s interactive pages. Some sets also have Freesat HD built in, so you can watch their HD channels.
But, unless you have a TV that specifically includes FreesatHD or FreeviewHD built in, you will need a separate box to watch HD broadcasts. That might sound a bit frustrating if you’ve recently bought a TV, but over the next few years more and more TVs will include, at least, the capability to receive FreeviewHD as standard.
In the meantime, to watch TV in HD you need either a SkyHD box, a Virgin HD box, a FreesatHD box or a FreeviewHD box. To watch films in HD, you’ll need a Blu-ray player.
If you don’t have one of those, even if your screen is ‘HD Ready’, you’re not watching HD – you’re just watching SD through a magnifying glass.