The massive digital switchover programme being co-ordinated across the UK right now is nowhere near the last word in digital TV. After all, it only just includes hi-def, and doesn't make any allowances for mobile TV, or moving Freeview onto broadcast standards that make the most of its very limited bandwidth.
In fact, the UK doesn't even have a plan for digital TV beyond 2012. Media regulator Ofcom's plans stop abruptly at this arbitrary date and, officially, it's not even working on a long-term plan. Fortunately, members of the Digital TV Group and the European Broadcasting Union have gazed into the next decade to what they call Digital TV 4.0.
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So how does the map look – from the roots of digital TV to the future?
Digital TV 1.0: the experimental years
Compression: MPEG-2 SD
The ups: First generation digital satellite TV systems took off in Europe. Standard-definition video offered a huge leap ahead, allowing five or six channels on a single transponder compared with just one analogue signal.
This quickly led to an explosion of new channels from the Continent, although the UK was slow off the mark. A few extremely tech- savvy enthusiasts soon realised you could do interesting things with these new digital receivers – like Nokia's groundbreaking D-Box – leading to the fondly remembered Dr Overflow project.
The newly established DVB standard brought some major advantages like electronic programme guides more dynamic than old-fashioned teletext. The common interface standard also enabled a receiver to handle multiple encryption formats with a cheap plug-in module. The pirates were close behind, seeing new weaknesses to exploit in the new digital encryption systems.
The downs: Like a trip back to the early days of analogue satellite, there weren't many channels, although you could use your analogue Sky dish to watch the first digital channels on Astra 1. But it was a great excuse to go out and buy a new receiver.
Look and sound: Most of the early signals weren't heavily compressed, so they looked very sharp and clear. CD-quality stereo had been demonstrated before on Astra Digital Radio, but never with pictures. Sparklies were a thing of the past, but the 'cliff effect' meant that you couldn't tune to poor signals in the hope of a grainy picture. A few dB separated a perfect picture from picture artefacts and choppy sound, then nothing at all.
Digital TV 2.0: the explosion
Compression: MPEG-2 HD & SD; MPEG-4 SD
Broadcast: DVB-S, DVB-T (2K & 8K)
Platforms: Satellite, terrestrial, cable, broadband
The ups: Digital TV for everyone. Well, you have to pay at first but Sky goes from strength to strength. Eventually everyone gets to enjoy the benefits when Freeview is born from the ashes of ITV Digital, and it's enormously popular.
Across Europe an explosion of free TV channels offered even more ways to peek into the cultural life of our neighbours. Outside the UK, though, most subscription services suffered terribly at the hands of highly industrious TV pirates. Still, it's good news for expats and football fans, with the parallel revolution of internet access making it easy for anyone to update a pirate card.
There were almost too many new ways to enjoy TV. The BBC and Sky competed with experiments in interactive TV – multi-screen, alternative soundtracks, shopping, banking, email, digital text. A lot of them fell by the wayside and most had to be rebuilt until they worked the way people wanted, but the red button was here to stay.
Personal video recorders brought the possibility of capturing digital streams with no loss of quality, and having more than one tuner in a box, but it took Sky to make it popular with Sky+. Freeview eventually cottoned on and created Freeview Playback with the help of the BBC and DTG.