Unscrambling the high-definition TV picture

August 25, 2005|By MIKE HIMOWITZ

OVER THE years, I've been an early reviewer of new technology but rarely an early adopter. Unless a new gadget promises a quantum leap in performance - or does something that was impossible before - I'm unlikely to be in the first wave to hit the beach. I've saved a lot of money and grief that way.

Eventually, though, a new technology becomes good enough, or affordable enough, to make the leap into our personal lives. High-definition TV is getting there - in fact, it reached our house two weeks ago, and made its HD debut on Monday. That's how long it took Comcast to arrive with the black box that actually turned the HDTV into an HDTV.

Confusing? That's part of the "joy" of buying HDTV. It's the most complex and confusing example of consumer electronics I've seen in 20 years of writing about technology.

You can spend $10,000 for a flat panel, home-theater monster that covers the better part of a wall, or about a tenth of that on an excellent 34-inch set like the one that hides in a corner cabinet in our living room when we're not watching.

The problem: To buy wisely at any level, you'll have to learn a lot more about the technology than you had to know to buy your last set. Since the government says the future of television is digital, and TV makers will do everything they can to push high-definition sets, I'll spend some time sharing what I learned in the process of buying one.

The basics: High-definition sets are different from the last generation of TVs in two ways. First, they receive a digital signal, which is incompatible with traditional broadcasts but allows more information to be transmitted. This allows TV stations to provide additional channels, a better picture on existing channels, or a mix of the two, depending on the time of day.

Eventually (most likely in 2009), we'll all have to buy digital sets or new digital tuners for our old sets if we want to receive over-the air broadcasts. For the time being, however, local broadcasters and cable companies are providing both signals.

One of the benefits of digital broadcasting is the opportunity to greatly improve the "resolution" of the TV image. High-definition sets use more "dots" of light, or pixels, to produce an image than standard TVs. Typically, TV makers refer to these as "lines" of resolution. Standard TV sets in the U.S. produce 480 lines of resolution. Most true HDTVs can produce 1040 lines, although some manufacturers peddle lower-resolution sets that they market as HD.

HD broadcasts provide significantly more detail than standard fare. They're also more expensive to produce, which is why the selection is still relatively limited. HD sports are outrageously great. You can count the hairs on a quarterback's beard halfway across the field with a good HDTV signal - if you're into that kind of thing. Movies with spectacular scenery, lots of action and explosions are also a epiphany in HD format - particularly if you have a home theater sound system.

This is one reason why 99 percent of these sets are bought by guys. Your average Meg Ryan chick flick won't look much better in HDTV. In fact, more than a few actresses hate the higher-resolution screen - too much detail.

The first thing you'll notice when you shop for HDTV is that the screen is likely to be a different shape. It seems shorter and wider than your current TV.

This is the aspect ratio of the screen -width to height. The standard TV screen we've watched since the late 1940s has a 4:3 aspect ratio. That ratio is pleasing to the eye and was relatively easy for makers of cathode ray tubes to produce - one reason it was adopted by the computer industry, too. It was also the most common aspect ratio for Hollywood movies until the 1950s.

But as time moved on, movie directors increasingly produced films with a much wider aspect ratios - 14:9, 16:9, or as extreme as 5:2. The goal was to engage our peripheral vision in the theater and evoke a greater sense of reality. Unfortunately, this soon created a disconnect between TV and motion pictures, which increasingly became a major source of broadcast material.

One way to solve this problem is to edit a widescreen movie for TV, so that it fits in the 4:3 window. Unfortunately, this means cutting off the edges of the action, or spending time and money to "pan" the screen during edit to provide the best window onto the film image.

The other alternative is to show the movie in its original aspect ratio. Purists prefer this, but it creates black bands of unused screen at the top and bottom of a standard TV, a technique known as "letterboxing."

When the TV industry began contemplating high-definition programming, it decided on a wide aspect ratio of 16:9, which, is much more theater-like than standard TVs and works much better for movies.

As a result, most HDTVs are so-called "widescreen" models. But they don't necessarily have to be - high definition only requires a minimum number of scan lines. You'll find some HDTVs with a 4:3 aspect ratio.

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