by Craig Johnston ~ April 26, 2006
Just when you thought you were getting the hang of HDTV, Japan's NHK has brought Ultra High-Definition TV to NAB. It's in a theater in the back of the Central Hall, and it's worth seeing for many reasons, but primarily because what you're seeing is not possible.
How is it not possible? Well, it's a 4320 scanning line system. They don't make imaging chips for that, there is no server made that can record and play back that rate of uncompressed data, and there is no projector available for displaying such an image.
But it's there, four times the horizontal resolution of today's HDTV; four times the vertical resolution; and 16 times the resolution in all. You could fit a 4 x 4 array of HDTV pictures on the 400-inch diagonal screen. How do they do it? Basically, they use two of almost everything.
The Ultra High-Definition camera has a set of 8 megapixel, 2,160 scanning line red, green and blue CMOS sensors, and a second green CMOS sensor. The second green chip is offset one-half a pixel diagonally, which allows the camera to deliver all 4320 scanning lines. Do you follow so far?
From the camera head, 16 HD-SDI signals are sent through an optical transmitter and then on to a pair of top-of-the-line universal data recorders, 8K Digital Cinema UDR-20S/20E recorders. Those have to play back in sync during projection.
NHK uses the same offsetting trick with the projectors. There are two of them, one delivering the red and green pixels, and a second delivering the two green pixels to the screen. The second set of green pixels is offset diagonally by that same one-half pixel. Voila, a 4320-line system.
All the equipment, including a prototype camera, samples of the CMOS sensors and other hardware, are available on display in a 12-minute presentation.
"It's fantastic," said FCC Commissioner Deborah Taylor Tate. "I don't even have HDTV yet, and this is Ultra High-Definition." She said her favorite scene was the sea of sunflowers.
The scene was amazing, with no artifacts apparent. A couple of scenes later, there seemed to be an almost 3D effect. In addition to the pre-produced material, NHK put an ultra HD camera on the LVCC roof to add a live picture to the mix.
Sound was not an afterthought at the Ultra High-Definition presentation. It utilizes the world's first 22.2 multichannel sound system, which consists of three vertical layers of loudspeakers producing surround sound, which in turn allow viewers seated anywhere in the theater to experience the same high-quality sound.
Over a million and a half people saw Ultra High-Definition in Japan at the 2005 World Exhibition, but NAB is its first stop outside Japan.
For those of you forward-thinkers, don't go shopping for Ultra High-Definition cameras, transmitters or home sets right away. NHK officials said Ultra High-Definition's rollout to the masses is about 20 years away.
© 2006 NAB