In 1936, the BBC introduced its viewers to high-definition TV. (Well, that's what they called it, anyway.) The Beeb's new broadcast system produced a blurry, black-and-white 405-line image. Still, it was a lot better than the 30-line standard it replaced. Seventy years later, the name's the same; only the specs are different. High-definition TV has morphed into a color system with up to 1,080 scanning lines. But just as Americans are beginning to embrace the new HDTV era, the definition of high definition is changing once again.

The Japanese national broadcaster NHK, which created the first modern HDTV system in the 1970s, is working on that system's successor, Ultra High Definition TV. Its resolution will be so high it'll make your new big-screen plasma look about as sharp as the 1950s Sylvania HaloLight in your grandparents' attic. But don't fret — NHK doesn't expect Ultra HD to hit the market until around 2025.

The new system will offer 16 times the resolution of today's HD, which maxes out at 1,920 pixels of horizontal resolution and 1,080 pixels of vertical resolution (pixel columns by pixel rows); Ultra HD will have a whopping 7,680-pixel horizontal resolution by 4,320-pixel vertical resolution. NHK also plans to use 22.2-channel surround sound, with ten speakers at mid-height, nine above your head, and three at your feet. Bullets won't just whiz by — they'll practically brush up against your nose. Great stuff — if you're watching TV on a display the size of the DiamondVision screen at Yankee Stadium, that is. NHK is demo'ing Ultra HD on 440-inch (36.7-foot) screens — which makes sense, because watching it on a regular-size set would have about as much impact as viewing an HDTV program on a cellphone.

Nobody knows yet how Ultra HD's monstrous amount of data can ever be sent over cable, satellite, or the airwaves. And the technology NHK is working with is relatively primitive. To display the images at demos, it needs to use two projectors; the image size is so large that one alone can't create a bright-enough picture. And uncompressed Ultra HD files are enormous. The video is recorded at 24 gigabits per second, compared to 1.5 for standard HDTV. The hard drives used to store the data weigh 600 pounds, and 18 minutes of video requires 3.5 terabytes of space. But the work NHK engineers are putting into it shows that no technology ever remains static.

When HDTV became available here in 1998, Joe Flaherty, a CBS engineer instrumental in its development, famously said that "today's HDTV images are the worst HDTV we'll ever see." And he was right. As technology improves, HDTV just keeps getting better. But any display is only as good as the material available to show on it. To improve the picture quality of both DVD and the new HD DVD and Blu-ray formats, as well as movies seen on cable or satellite, the movie industry is using a technique called oversampling. By creating digital masters at twice the resolution of HDTV and then downconverting them, technicians can preserve all the content found on the original 35mm film.

Joe Kane, founder of the Imaging Science Foundation and creator of the Digital Video Essentials DVD, discovered that when he created a video master without oversampling, he lost resolution. "A transfer done at 1,080p by 1,920 resolution produced only 800 to 900 lines of resolution," he says. The solution: Make a digital master at 4K resolution ("4K" refers to 4,096 pixels of horizontal resolution) and down-rez it to create the disc. When you see the pictures on a 1080p display, "there's a day-and-night difference," Kane says. "There's detail in the picture — it looks a lot more real."

John Lowry, a film restorer and chief technology officer of DTS Digital Images in Burbank, California, uses 4K transfers to restore damaged film prints to pristine quality. Creating a new 20-title collection of James Bond DVDs for release this fall, Lowry worked in 4K for the films that were in the worst shape because he needed as much resolution as possible to remove scratches and other artifacts from the masters. "Dr. No, made in 1962, was almost a B movie," Lowry said. "No one knew they had a major franchise when they made it. There was a tremendous amount of dirt and film-gate hairs all over the place."

Lowry uses 4K mastering to create both standard- and high-def discs. This lets him improve the picture by filling in information missing from one frame by transferring it from another, nearby frame. Lowry and his team have developed their own software, which runs on a fleet of 700 Macintosh G5 machines. Material is stored on 700 terabytes of disc space running off a Linux operating system.

If 4K transfers are great, wouldn't a 6K or 8K transfer be nirvana? Nope. According to Lowry and others, 4K is even higher than the resolution 35mm film can capture. So transferring at a higher resolution would just be a waste of time. "In the real world, I've rarely found any material that exceeds 3.5K in resolution," Lowry says.

A 4K transfer gives the best possible image quality, right? Not so fast. Resolution is important, but it's not the only factor. Try watching a high-def movie on a 1080p display bathed in bright sunlight and you'll catch my drift. No matter how good the resolution, a washed-out image will still look pretty lousy, even if it boasts millions of pixels. That's why Lowry thinks that NHK's work on Ultra HD, while impressive, is an example of engineers barking up the wrong bit.

Many things contribute to the impression of picture quality. For example, better sound creates the sense of a better picture. And improved dynamic range — a TV's ability to display a wide luminance range from dead black to peak white — makes the image appear sharper. New display technologies, such as Toshiba's SED system (see "The Future of Flat,"), can yield dramatically improved contrast that imbues a high-def image with a sense of richness not otherwise obtainable.

That's why Tomlinson Holman, president of TMH Corporation andinventor of the THX cinema standard, calls the traditional concept of high-def "irrelevant." The point isn't to just use the most pixels, but to create a combination of improved resolution, widescreen imagery, and surround sound that changes the nature of the viewing experience. "HDTV was the wrong pitch," Holman believes. "It should have been called 'high-impact television.'"

As for the near future, the bottleneck to better picture quality will remain where it's always been: with video's gatekeepers, the cable and satellite companies. They won't talk about it, but to squeeze more channels into their available bandwidth, both industries regularly compress their channels to the point where both standard- and high-def picture quality often suffer — no matter how good the source material is. But that's a whole other story ...

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