With the first Freeview HD transmissions scheduled to start on the 2 December in the London, Liverpool and Manchester areas, Register Hardware answers all your questions about the new telly technology.

New Zealand's Freeview HD logo. What will Blighty' look like?

What do I need to receive Freeview HD?
You’ll need a TV or set top box with the Freeview HD logo. Getting the logo involves certification for both the video encoding and the transmission systems, as well as an updated version of the interactive (digital text) engine. Simply having a TV with the ‘HD Ready’ logo is not sufficient. You should also look out for the DVB-T2 logo.

When will it be coming to my area?
The first transmissions will start at the Crystal Palace and Winter Hill transmitters on 2 December 2009. In areas that have already switched off the analogue signal, HD transmissions will start over the next year, and roll out to other regions as switchover happens, with a few exceptions. Click here or the full timetable.

Will my existing ‘HD Ready’ set work?
Not without an external set-top box. The ‘HD Ready’ logo just indicates that the screen is capable of showing an HD picture, and that there are sockets that allow you to connect something producing one, like a Blu-ray player or an HD receiver. It does not mean that the tuner or decoder in the set is capable of understanding HD signals – there’s a separate (and seldom seen) ‘HD TV’ logo for that.

For a definition of the logos, see this crib-sheet (PDF).

So have I been mis-sold?
If you can be certain that someone sold you an ‘HD Ready’ set and told you it would receive Freeview HD when it launched, then maybe. The ‘HD Ready’ logo was defined in 2005, so sales assistants should know what it means by now, and it’s been clear for over a year which technology the UK would use to receive HD – and that it ruled out equipment designed for HD in other countries.

What about ‘product X’ – the advert and specs say it can receive terrestrial HD?
There are some set-top boxes, tuners for PCs and even a few TVs which claim in their specs to receive terrestrial HD. At the time of writing, none of those is compatible with the system that will be used in the UK, though they should work with terrestrial HD broadcasts in France and a few other countries. If an advert says a product works with freeview HD, the most charitable interpretation is that they mean 'free-to-view HD terrestrial broadcasts in countries using DVB-T'.

Humax's upcoming Fox-HD-T2 Freeview HD set-top box

When will Freeview HD products be available?
There may be very limited supplies around the end of this year, but we expect that most of the main manufacturers will unveil their 2010 product ranges early in the new year, and will include models compatible with Freeview HD then, including integrated TVs, set-top boxes and DVRs.

What technologies are being used for HD in the UK?
Two technologies are being introduced to terrestrial broadcasting for Freeview HD. The first is the H.264 - aka AVC, or MPEG 4 part 10 - video codec. This can be used for both HD and SD pictures, and is much more efficient than the MPEG 2 codec used by Freeview at the moment. H.264 is already used for satellite HD services, and for terrestrial HD in other countries.

The second technology is called DVB-T2, which is a brand new transmission method which the UK will be the first country to deploy. It’s this that means that current equipment will not be able to tune into the Freeview HD service, as all current terrestrial products use DVB-T, rather than DVB-T2.

Why are we the only people using DVB-T2?
We’re the first, but other countries are planning to roll it out too. The NorDig group, which sets specs for the Nordic countries, has drawn up a common receiver specification based on DVB-T2. Tests are underway in Sweden, and the construction of a Finnish HD DVB-T2 network is due to start this year. Serbia and Slovakia are both also planning DVB-T2 services.

Pace has shown off a prototype Freeview HD box, perhaps not unlike its TDC685 cable STB (pictured)

Can an existing receiver be upgraded?
No. DVB-T2 isn’t a question of firmware. It requires compliant tuner modules which receive the broadcasts and feed the transport stream data to the rest of the system. It’s much more complex than DVB-T, and as the tuners use dedicated silicon, they can’t be upgraded. A DVB-T tuner won’t make any sense of a DVB-T2 signal, no matter what software the rest of the system has.

The H.264 codec requires new hardware too, in most cases other than general purpose PCs. Set-top boxes rely on custom decoding hardware to do the hard work at a reasonable price, and most current ones just understand MPEG 2 at standard definition.

What about using the CI slot on a digital TV?
It’s not very practical. A French company called Neotion has made modules that can convert H.264 to MPEG 2 in a CAM (Common Access Module) but the use of DVB-T2 means you’d need almost a whole set-top box in the CAM. Controlling a CAM through your TV’s menus isn’t very straightforward, and may not be possible without an upgrade to the TV’s firmware anyway, as most sets only expect to use the CAM for encrypted channels. Some older sets will only have an SD MPEG 2 decoder, so still wouldn’t be able to show H.264 HD pictures this way.

Why not use the same standard as everywhere else?
To make HD practical on terrestrial television, using H.264 is essential, unless lots of other channels are turned off to make room. Lots of existing sets made for the European market would work if we used H.264 with DVB-T, but even more wouldn’t, as they lack any HD tuner or decoder at all – only some sets made in the last couple of years would cope, so many people would need to upgrade anyway.

With DVB-T2 providing much more bandwidth, in the longer term it’s likely that a change to that standard would happen anyway. Launching HD now, and then using the new transmission technology later would force many people to upgrade twice in a short time, once for H.264 and then again for DVB-T2. By linking the two upgrades together, the intention is to ensure that once you do buy into Freeview HD, you won’t have to upgrade again for a long time as we should have the most technically advanced terrestrial TV system in the world.

What’s so special about DVB-T2?
DVB-T2 can provide more capacity for programmes than DVB-T. Tests suggest around 60 per cent more capacity for the same robustness of signal. With DVB-T, it’s often been a much harsher trade-off, for example with the main BBC multiplex being more robust, but carrying fewer channels than the ITV/Channel 4 one, and some multiplexes being more susceptible to interference.

You can read up on the maths behind T2 here (PDF).

Does this mean my existing equipment is obsolete?
No. Only one of the six multiplexes - the digital TV transmission frequencies, essentially - in the UK is converting to DVB-T2. All the others will continue broadcasting DVB-T with MPEG 2 pictures for the foreseeable future. You will be able to continue watching the existing Freeview channels, and you only need to invest in new equipment if you want to watch HD services.

Will more channels move to the new technologies in future?
It’s possible, and during the downtime of the HD channels, they may sublet capacity to other channels, perhaps SD ones using H.264 video. But we’d consider it very unlikely that all the current DVB-T/MPEG 2 transmissions will cease much before the 2020s - the BBC won’t be in a rush to disenfranchise viewers, and the operators of the commercial multiplexes won’t switch over until they can convince their customers (the channels they carry) that they won’t lose out on audiences by switching to DVB-T2/H.264. Yes, in the long term, all the multiplexes will probably move to DVB-T2 and H.264, even for SD. But like we said, don’t expect it any time soon. ®