Posted on

Smart TVs attacked over the airwaves

A group of researchers from Columbia University have published the results of some experiments with mixed mode digital TV broadcasts here.

The problem is that the new but widely implemented HbbTV standard allows HTML to be embedded in with the picture data. What could possibly go wrong?

Well apart from the fact you only need an encoder and transmitter to mess up all the sets in range by sending them HTML spam, the Columbians reckon that with the right HTML you can turn people’s tellies into a botnet and attack targets through their internet connection. I’m not yet convinced this will work in practice, but building a web browser in to anything has always been risky when it implements more than plain HTM. It’s always been possible to broadcast alternative TV and radio signals over the top of legitimate channels, but generally, it doesn’t happen in practice.

 

Posted on

Digital TV for people who don’t much care

Yesterday an old friend called to ask me for an explanation of this digital TV business as she needed to relocate her set and thought it was time for a sort-out. I’m not a TV fanatic; there are no plasma wide-screens hereabouts. However, she’s not what you’d call an avid TV viewer either, so calling me did make sense in a way.

So what is the current TV story for those of us who aren’t aficionados? This is how it is.

As the government as pointed out, ad nausium, the old TV system is being switched off. That’s the TV we all grew up with – transmitted form a mast on the top of a hill somewhere and received by an aerial on your roof. This was analogue.

Analogue is not dead. There are still going to be analogue transmissions from satellites and on cable TV. However, unless you have a particular wish to watch the local news in Mongolia you’re probably not going to be interested. It’s only for specialist foreign channels; your garden will look like Goonhilly and the kit will be expensive and cumbersome.

So apart from the TV junkies, most people will want just digital TV. The only questions you need to ask are “How should I get it?” and “Do I want High Definition?”

The digital TV system is called DVB (Digital Video Broadcast). There are three basic versions: DVB-S for satellites, and DVB-T, which means terrestrial (i.e. broadcast from a transmitter on the top of a hill), and DVB-C which is sent down cable TV. Cable TV arrives down a cable laid to your house and an expensive subscription to a cable TV company. Everyone hates their local cable-TV monopoly. Unless you already know you want cable TV for your own reason, you probably don’t want cable TV.

For DVB-T and DVB-S there are both free and subscription services:

DVB-T: Freeview and Top-up TV
DVB-S: Freesat and Sky

Please generate and paste your ad code here. If left empty, the ad location will be highlighted on your blog pages with a reminder to enter your code. Mid-Post

Both systems need a specific receiver, which can include a decoder for subscription-based channels should you want them. These receivers cost:

DVB-T: ~£30 (but often built into TV sets, especially since 2007).
DVB-S: ~£50 (just starting to appear built-in to some high-end sets).

Here’s where it starts to get tricky. If you do want High Definition (HD) you can only get it on DVB-S (satellite) and you need a special HD receiver box. These cost £150 instead of £50.

With HD the picture is simply made up of more dots than on a standard picture. HD is only worth it if you have a large HD-compatible TV. On a smaller set the dots are so small anyway that you won’t see the extras, and if the set is not not HD-compatible you’re definitely wasting your time. The HD Satellite standard is often referred to as DVB-S2.

You can have a mixture of standard and HD satellite receivers, once you have the dish and the wiring in place, so if you have small sets you can use a standard receiver and get an HD receiver for the big set in the garage, or wherever you keep it.

You can, of course, get an HD receiver ‘free’ from Sky. You’ll see such offers all over the place (Tesco current has posters up offering a free Sky HD box with this set). In the small print you discover you need to take out a subscription to Sky TV for a couple of years – something like £500. This is fine if you want the Sky channels; the only people who I know who feel its worth it are the sports fanatics wanting a wide choice of live football.

What’s coming in the future, just to confuse matters, is HD on Terrestrial transmitters – DVB-T2. This doesn’t exist yet, but is planned for later 2009 in some areas. We’ll have to wait and see what actually happens but it won’t work with standard DVB-T (Freeview) equipment even if a TV does say ‘HD Ready’.

If you think it’s time to upgrade your TV you can buy one with a Freeview (DVB-T) receiver built in. In fact, since the start of 2009, you’d have been hard pressed to find one without it. Unfortunately if you want a built-in satellite receiver then you’ll have to wait. There are some around; they’re quite rare and expensive. Give it a year and I suspect they’ll be common enough too.

So to summarise, if your TV has a screen less than about 32 inches either get a new set with Freeview (DVB-T) or a £30 receiver box to work with your old set. If it’s bigger than 32-inch you’ll get a better picture with Freesat, but the decoder box will cost more and you’ll need to install a satellite dish. Or you can wait until 2010 (or later) when DVB-T2 turns up and gives you HD through a normal aerial. It depends on how good a picture you want.