But the engineers behind hi-def have moved on, and are already publicly showing a TV technology 16 times more powerful than HDTV.

Called Super Hi-Vision (and often known as 8K4K or Ultra HD), the system has been developed by Japan's national broadcaster, NHK, and the same engineers who worked on the original Hi-Vision (hi-def) tech in the 1980s.

NHK's Super Hi-Vision Ultra high-definition TV system – to give its full name – is built around images with a 7,680 x 4,320 pixel resolution, equating to roughly 33 megapixels. The current pinnacle of hi-def, Full HD, measures just over two megapixels.

It's a huge jump, but there's more. Alongside these super-sharp images is a 22.2-channel audio system that uses banks of speakers on three levels, strung across the entire length of the 10m x 5m screen installed at NHK's Tokyo labs.

Pushing the boundaries

Nobuyuki Hiruma, associate director at NHK's Science & Technical research Laboratories in Tokyo, thinks that the Japanese broadcaster's work on Super Hi-Vision is only natural. 'When colour TV was introduced we started our HDTV research, and now HDTV is common we have started the research for the next generation,' he told Home Cinema Choice magazine.

Hiruma explains that the Super Hi-Vision Ultra HD project is based on research into the human vision's maximum parameters; NHK has deduced that only 8K4K resolution fully reflects the subtle abilities and nuances of 20/20 vision. This comes from NHK's belief that the Digital cinema standard, which is slowly being introduced into global cinemas, and uses less pixels (4K2K to be exact), is not entirely up to scratch. There is, he says, a key difference between the two. '4K2K is a digital system designed to cover the resolution of film,' says Hiruma, 'but Super hi-Vision is based on research into human vision.'

To appreciate its clarity, Super Hi-Vision needs to be seen on a display measuring at least 100in across. But to really ram home its stunning pixel density, NHK demonstrated the tech on a screen measuring 450in. The image quality was almost indescribable. By way of comparison, Hiruma thinks Digital cinema may only need a 50- or 60in panel to be appreciated.

High up on scaffolding in the Super Hi-Vision studio lurk two JVC D-ILA projectors, each capable of producing 4K2K resolution images. Masaru Kanazawa, executive research engineer on the SHV project, explains what's going on: 'We are projecting the image from two projectors using four LCD panels,' he says. 'This is the only way to get the brightness and resolution. We don't use any compression. We don't want to deteriorate the picture quality, but of course for transmission, ultimately we will need to develop some form of lossless compression.'

Whatever the solution, it's certain that Super Hi-Vision will require a completely new generation of satellites. Kanazawa explains that the 15-minute Ultra HD presentation NHK has prepared constitutes 3.5 terabytes, something that makes filming and editing a painstaking frame-by-frame process. A day's filming, which involves carrying around two cameras and a pair of huge hard disk drives, then takes a whole night to back-up.

But the effort is definitely worthwhile. NHK's Super Hi-Vision demo film is a phenomenon. It includes eerie winter scenes filmed in Japan's mountains, shots of wildlife that redefine the phrase 'close-up' and stunning panoramic views of Hawaii filmed from a paraglider. It's eye-searing stuff.

NHK insists that such super definition is no pie-in-the-sky folly. As a first step towards a Super Hi-Vision future, NHK wants to trial 4K2K broadcasts in Japan by 2010. Its aim is to start public broadcasts just in time for the 2016 Olympics – Tokyo is in the running to host the games. The state broadcaster's plans for Super Hi-Vision itself are almost as ambitious. Test broadcasts are planned for 2015 – and 10 years later it hopes to begin full-time broadcasts.

To whom is unclear. The mind-blowing quality and size of Super Hi-Vision is obviously ideal for large audiences and outside broadcasts. The BBC has already said it hopes closed-circuit Super Hi-Vision feeds of the 2012 Olympics in London could be shown on outdoor screens in major cities around the UK.

These ambitious plans depend on finding a way to physically shunt the huge amounts of data – and the BBC's part in all of this shouldn't be underestimated...

Well done Auntie

Engineers working at the BBC Research & Innovation department have played a crucial role in the development of all sorts of TV firsts. Nicam Stereo, Teletext, Freeview+, DAB radio and the BBC iPlayer are just some of its successes – and now an esoteric codec named Dirac is helping bring HD to the masses.

Dirac – essentially a MPEG-2/h.264 video compression technology – was key in allowing the BBC to show over 300 hours of HD coverage of the Beijing Olympics on the BBC HD channel. But the BBC and its Dirac project is also helping NHK realise its 8K4K ambitions in Japan.

It was crucial in Super Hi-Vision putting on its best show yet at September's IBC exhibition in Amsterdam. Hosted at NHK's purpose-built demonstration theatre, this was very much a collaborative project. Under a joint venture called the Broadcast Technology Futures Group, NHK teamed-up with the Beeb, Italy's State broadcaster RAI, and the European Broadcast Union (EBU). With the help of Siemens, Cable & Wireless and Eutelsat, the aim was to broadcast Super Hi-Vision internationally via both cable and satellite.

An SHV camera high above the Thames sent live pictures into Amsterdam over fibre-optic cable, while a server in Torino supplied heavily compressed pre-recorded content via satellite. It was then shown on a seven-metre screen.

A world first and a complete success, the project scooped a special award from the IBC organisers. 'At IBC this year we were able to prove that the international transmission of Super hi-Vision content is both possible and practical using optical IP and satellite links,' boasts Hiruma.

Wait and see

The question on every AV fan's lips is how long it will be before 8K4k becomes a domestic reality. The answer is 15 years at least. And maybe never in the UK.

'At present we estimate that it will take around ten years to establish the technical foundations to bring SHV into homes,' says Hiruma, 'and we predict that SHV broadcasting will be introduced sometime in the mid 2020s.'

Prototype cameras and projectors are being used for now, so there's a way to go before Super Hi-Vision can become a bona fide broadcast technology, but it could be coming to a city centre near you in as little as three years.

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