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Insight... NHK + Ultra-HD

by Chris Forrester

For this issue, Chris journeys to Japan to receive an update on Ultra HDTV, which some suggest is the absolute Holy Grail for the satellite TV industry.

A few hundred metres from Japan’s public broadcaster NHK’s (Nippon Hoso Kyokai) giant R&D facility is Ultraman park, and an impressive statue to Ultraman, a 1960’s TV futuristic superhero series that’s remembered fondly by Japanese adults of a certain age. Indeed, the show was produced in a local studio and in the district called UltraTown by residents. NHK’s laboratory is nothing if not futuristic, with its 240 highly qualified researchers, of which 78 hold doctorates, and all focussed on tomorrow’s TV.

Japanese public broadcaster NHK will start experimental test transmissions of its spectacular Ultra-HD system (7680 x 4320 pixel) in 2011-2. Japan switches off its analogue terrestrial transmissions on July 24, 2011, and NHK will retain some of the frequencies permitting expansion into next-generation HDTV.

Dr. Kenkichi Tanioka, director general of NHK’s science and technical research laboratories, was outlining NHK’s timetable at a major presentation recently in Tokyo. He stated he anticipated further testing and development taking until 2016, with implementation to follow.

“The biggest problem is bandwidth,” he said, but praised the co-operation agreement now in place between the BBC (British Broadcasting Corporation), NAB (National Association of Broadcasters), RAI (Radiotelevisione Italiana)and the EBU (European Broadcasting Union), which he described as a mutual approach to the evolving technology. He admitted that precisely predicting the future for Ultra-HD was especially difficult, “but we already make possible the impossible,” he stated. He sums up NHK’s philosophy as being a, “duty to innovate,” while stressing that technology and the efforts of his teams is of no use at all if it remains in the Lab. “We want applications that viewers can eventually enjoy.”

And there are plenty of signs that NHK’s work does trickle down to public relevance. There’s the ready-to-deploy ‘News Flash’ early warning system, which automatically sends alerts to radios, TV sets, mobiles, and even alarm clocks, of an impending shake, or Tsunami, to the nation’s always ‘on the edge’ population. There’s its clever ‘One Seg’ (for one segment) TV-to-mobile system, and approximately 60 other highly active projects including 0.3-inch pixel advanced plasma display with its wonderful resolution possibilities. But the Jewel in the Crown, the Holy Grail, and their ultimate prize is undoubtedly its work on Ultra HDTV.

Unlike in the past when broadcasters from the USA, Europe, and Japan fought each other over rival TV transmission systems (the USA’s ‘Grand Alliance’, EBU’s DVB (Digital Video Broadcast) and Japan’s analogue Muse, and then Hi-Vision digital system, are all different), there seems to be a wish from all parties to avoid costly and overlapping efforts in the search for next-generation HDTV.

The progress made on this technology over the past 24 months is nothing short of remarkable. During this time period, they’ve mounted exhibitions at IBC (International Broadcasting Convention) and NAB, and (literally), bit-by-bit, improved compression ratios (helped by the BBC’s codec DIRAC system named after British physicist Paul Dirac), made significant improvements to their 33-million pixel camera lens, complete with its high-speed, wide-band processing circuits. They’re now ready for further size reduction and integration. They’ve developed prototype transmission circuits that significantly reduce the challenges for actual broadcast. Both the BBC and NHK are making steady progress on the compression algorithms, which have already brought the bit-rate down from a massive 28Gb/s to a more reasonable 120Mb/s.

All that remains is to get the signal up to a satellite. NHK is contemplating a new breed of satellite (“Kizuna” meaning Wind) that uses the 21Ghz Ka-band. One clever thought is to design and build the new satellites with phased array antenna technology that concentrates the strongest beams to those regions of Japan, which traditionally suffer from heavy rainfall.

NHK is also experimenting with 16APSK (Amplitude and Phase-shift keying) and 32APSK transmission schemes, in an attempt to compact this particular ‘quart through a pint pot’! NHK is also reviewing what they call ultra multi-level OFDM technology (1024QAM), and again with the intention of expanding transmission capacity. None of this work is likely to result in over-night success, but it is a sign of the commitment of NHK towards engineering excellence.

Dr Tanioka explained that live test transmissions will take place in London this coming September, with the signals transmitted to the giant IBC broadcasting technology convention in Amsterdam. NHK is working with the BBC to choose the best location to site the 33 million pixels Ultra-HD camera. One possible location is London’s South Bank near City Hall and Tower Bridge, with a backdrop of the City of London’s financial district.

Visitors to IBC this September will be able to see the fruits of this labour. The Ultra-HD images are as stunning as ever; the 22.2 channel sound is as immersive as can be imagined. A few years ago, the prospects of 22.2 channels of audio might have caused a heart attack for wiring looms and a boom in speaker sales. NHK’s engineers contemplate ‘towers’ of speakers, delivering bottom layer, mid-layer, and bottom layer audio. Eutelsat is bringing in the Ultra HDTV satellite images to Amsterdam on a pair of its satellite transponders. Cable & Wireless will handle the cable feeds. NHK-captured content from Japan will be linked with live signals from a camera in central London (let’s hope it isn’t raining). Altogether, the IBC demonstrations promise to be spectacular.

As mentioned, the BBC is already working closely on the project with its DIRAC advanced compression system. Dr. John Zubrzycki, the BBC’s principal research engineer at Kingswood Warren, speaking in Tokyo, said they were very pleased with the way DIRAC’s development was progressing in software form, but the moment was approaching when it would be time for silicon hardware to be employed. DIRAC is achieving close to 1/200th compression, and a vital link in getting the massively fat 24 Gb/s signals down to a manageable 120Mb/s.

Peter Wilson, technical advisor to the BBC’s Research & Innovation division, who is also present in Tokyo, said the BBC DIRAC team had several directions to follow. “We are already standardising the technologies within SMPTE (Society of Motion Picture and Television Engineers), and our original intent was to focus on professional applications, that is for extremely high-fidelity images within the broadcasting environment, for post-production and for transmission links and possibly storage. We also have a hardware partner called New Media Technologies with products in the market. But the other side of the coin was our wish to see DIRAC used for transmission, including streaming. Here the emphasis is on bandwidth saving for transmission, but if we can achieve both, that is bandwidth saving, but also high quality end results, then we have a very appealing technology.”

Cable & Wireless will pipe these London signals to Amsterdam. Other pre-recorded material will be played out in Turin and beamed by a Eutelsat satellite to the Convention Centre. One of the challenges is that currently there’s only one camera, and the system’s hard disc drive can only manage 18 minutes of recorded material. Kohji Mitani, a senior research engineer working on Ultra-HDTV, said the next stage is to start adding content for the broadcaster’s archive. “Co-operation is essential, not just between us engineers, but between engineering and production. Engineers do not usually make good producers and cameramen, nor cameramen good development engineers. We need creative co-operation.”

Mr. Mitani and his colleague Yudi Nojiri, both big fans of IBC, confirm that huge progress been made this past year with the 33 million pixel camera. “We can now manage 10 times the sensitivity,” said Nojiri. “Last year capturing twilight was hard, now it is possible.” There are still obstacles to be overcome, not the least in terms of studio use, and a drive towards a single CCU chip (the camera currently uses 3 CCUs).

Then there’s the display end of the chain. Visitors to NHK’s Open Lab exhibition could see an extremely high-end, 8K high-contrast projector passing light over a 33 million pixel panel. The engineers claim this delivers the whitest ‘white’ yet available from a projector, and the blackest black, and shades in-between in a very wide dynamic range. NHK anticipates projection to be one of the end-uses for Ultra-HD (such as throwing images onto a full wall of the living room or den, with a kids’ corner sitting alongside the main screen area, as well as perhaps showing data in an opposite corner), they also recognise that display panels will also be needed.

There are already 2K display models creeping onto the market, but there are improvements needed before they can achieve 4K (7680 x 4320 pixels) super-fine resolution in terms of PDP (Plasma Display Panel) or LCD (Liquid Crystal Display). And the other Holy Grail is to combine 0.3mm pixel pitch while at the same time reducing power demands to below that of a small power station! NHK demonstrated such a unit, with a claimed power saving of 30 percent over similar sized units—and they are working on a 100 inch model with all the brilliance and luminosity needed for daylight viewing.

The prospects of Europe seeing full time transmissions of Ultra-HD in the next 20 years must still be treated with caution. But it is also a fact that huge progress has been made in this past year, Most experts recognise that the consumer electronics industry will be looking for the next ‘big thing’ probably in less than 10 years from now. Dr. Tanioka’s simple “duty is to innovate” seems to be working well. He said that it was sometimes difficult to predict accurately when a specific application would kick in, and none was more difficult to forecast that the likely introduction of ‘Ultra HDTV’. “But we already make the impossible possible,” he said, hinting that the much-quoted 20+ year prediction might be speedily compressed.

Towards Next Generation Displays
Chris Forrester

There are huge strides being made in display efficiency, and progress beyond 1080p 120 Hz (and even 240 Hz) models, and even breathtaking 8K units, are happening much faster than anticipated. South Korea’s Samsung in May unveiled their massive 82 inch (4k x 2k) prototype LCD panel, and claimed, with some justification, to be the largest commercial LCD TV in the world.

In fact, the unit measures 3840 x 2160 pixels in size, which is part of the problem. To fully appreciate this monster you will need to be viewing at a safe distance, or else definition is lost. Which is where NHK of Japan comes in. NHK funds, what is without doubt, the most advanced portfolio of R&D engineers in broadcasting. They have 240 very talented engineers (of which 78 hold doctorates) working on next-generation TV, which has been dubbed Ultra HDTV, and the technical shape and potential future for displays.

One area that hasn’t changed is NHK’s commitment to programming and technological excellence. The programming highlights are numerous, while it is worth remembering that NHK has been transmitting high-definition since 1989. That initial HD system was its analogue MUSE version. Not bad for an organisation that didn’t transmit its first TV signals until 1953. NHK went with digital HDTV (Hi-Vision) in 1994, while the USA, and especially Europe, were still arguing about how to achieve the technology.

NHK’s logic assumes that 33 million pixel TV cameras will happen, and that MPEG4 digital compression will be superseded, and that display technology (either projection or Plasma/LCD) will also evolve to handle Ultra-HD. Indeed, the assumption is very much that the initial market for this technology will not be for TV, but exhibition, museum and retail exploitation.

All the while the likes of Samsung, Sony, JVC, Toshiba and many others are also researching numerous variations on these themes. Dr. Kenkichi Tanioka, NHK’s director general of its Science & Technical Research Laboratory, who is driving these elements forward calls it,“making the impossible, possible. NHK’s (and Samsung and others) can all handle ‘true’ HD 8 megapixel displays of 3840 x 2160 with ease. The next step is to boost this resolution to 7860 x 4320. Indeed, NHK has achieved it in the research lab by bundling together four conventional 8k displays, each of 56 inches. But, as John Wayne might have said in a slow drawl, ”There’s not enough glass in the world” to scale this up to 100 inches across — yet. Or achieve the super-fine resolution they are aiming for.

Currently most display screens are next-generation sets of the X-VGA standard (through WXGA, SXGA, WXGA+, and more) but NHK’s concept, as well as the new SMPTE standard (2036-1-2007) takes this a major step forward.

NHK has developed ultra-fine 0.3mm pixel plasma display panels, vital to help create the longed-for 100 inch screens to make the most of Ultra-HD images – and in these energy-saving days, bringing the concept in with a 30 percent power reduction on today’s plasma models. NHK’s PDP use Strontium Calcium Oxide (SrCaO) electrode protection film to achieve ultra high-resolution while at the same time without losing degradation, and a 30 percent power-saving compared to today’s Magnesium Oxide displays.

There’s also a widespread expectation that IMAX-style projection technology will be needed in the home, and again NHK’s engineers have done the groundwork for a highly dynamic 33m pixel projector with a very wide range that clearly shows the colour black. Moreover, NHK sees us holding on to the normal 0.75 times sitting position. This means that viewers sit or observe the display at three-quarters of the screen height. So a 60 inch screen height would have viewers sitting just 40 inches away from the screen. Hence the drive towards 0.3mm pixel sizes, for an invisible, ultra-fine screen image.

Dr. Tanioka calls this work moving from “Next” to “You”, the ‘You’ element being us, the professional user, programme maker, and, ultimately the consumer.

Capturing Ultra HD images at studio production rates of up to 250 Mb/s is another huge challenge, and NHK’s technicians have developed a flexible high-speed, thin, rotating optical disc, with a very low error rate, that helps achieve this with stored media. The disc floats on a bed of air, and is so light and flexible that it bends and collapses under its own weight, hence the bed of air that creates a sort of sandwich between the spinning disc and the stabilisation board. It almost has to be seen to be believed, but the important thing is that it works, and is capable of recording at a massive 250 Mbps. Currently, the best NHK can do is to capture 18 minutes of stored media — but they’re working on more.

Key to the overall concept of Ultra HDTV is 22.2 channel surround sound. There’s probably been more tangible progress in this area than any of the developments. Now, instead of having 20 dedicated speakers scattered around the room (plus the sub-woofers) they have consolidated the units in six ‘tall boy’ speaker systems, with each set of speakers capable of handling bottom layer, middle and top layer audio, and delivering a truly immersive sound system.

Naturally enough, they are also working on 3D, although this technology is undoubtedly a little further off. They have developed Braille displays using optical touch panels that can display forms, figures and graphs onto a GUI display (being developed with the University of Tokyo).

They are also working hard on flexible displays. We all know the work being done by Sony and others on OLED (Organic Light–Emitting Diode) units, but NHK is working hard on lightweight flexible displays in what they describe as Organic TFT technology, designated QQVGA O-TFT. It has 5 inch working prototypes that unroll from a pen-sized holder.

NHK is planning to start testing Ultra HDTV in 2011-2012, and foresees the technology as becoming mainstream by 2020. It’s an exciting future.

About the author
London-based Chris Forrester is a well-known entertainment and broadcasting journalist. He reports on all aspects of the TV industry with special emphasis on content, the business of film, television and emerging technologies. This includes interactive multi-media and the growing importance of web-streamed and digitized content over all delivery platforms including cable, satellite and digital terrestrial TV as well as cellular and 3G mobile. Chris has been investigating, researching and reporting on the so-called ‘broadband explosion’ for 25 years.