Screening the selection of high-def TVs

From the questions I get this time of year, I can often tell what gadgets are going to be big sellers over the holidays. The winner in 2007 looks like HDTV, and with good reason.

Prices of high-definition sets may not be in free fall, as they were a year ago, but they're still dropping. Lots of high-quality models in the 42-inch range are available for $1,000 or less. If retailers get really antsy about the economy, Black Friday sales could drive prices lower.

That said, here are answers to the most-frequent questions I get.

• What kind of HDTV should I buy?

Answer: Manufacturers use several technologies to produce HD screens, including liquid-crystal displays (LCDs), plasma, rear projection and cathode-ray tubes. Each has advantages and drawbacks.

LCD: As the name suggests, flat-panel LCDs use liquid crystals, sandwiched between sheets of polarized glass and illuminated by a back light, to produce their images. It's the same technology used in laptop computers. LCDs can produce more lifelike color in a wider variety of lighting conditions than plasma or projection screens. But their blacks aren't as black and their contrast is lower, which robs images of some of their snap. Also, the image can fade when viewed from extreme angles (vertical or horizontal). LCDs are good values in smaller sets but can be too expensive in sets of more than 40 inches.

Plasma: These flat-panel sets, usually 42 inches or larger, create an image by lighting up tiny bubbles of gas embedded in the screen. Next to tube TVs, they produce the brightest, crispest image, with the best contrast, at any viewing angle. On the downside, plasma sets can suffer "burn-in" if an undisturbed image is left on the screen — even a "crawler," stock ticker or network logo. That caveat aside, a plasma screen is your best bet for a larger set.

Rear projection: These large-screen sets (typically 50 inches diagonally or more) are thicker than flat-panel models but thinner than tube sets. They use a small LCD or digital light processor (DLP) to produce an image. Often cheaper than large-screen LCDs or plasma sets, their images aren't quite as sharp and tend to fade as viewing angles increase. Unless you're looking for a very large display at a rock-bottom price, stick with flat-panel.

Cathode-ray tube: These big, reliable vacuum tubes were the TV industry's display of choice for more than half a century, but they've almost disappeared from the HD market. They still produce the best image — but their bulk limits screen size to 40 inches. If you can find a CRT, it could still be a good buy.

My recommendation: LCDs for sets under 40 inches, plasma for larger screens.

• Why do I see gobbledygook like "720p" or "1080i" in these ads?

What makes high-definition TV sets high-def is their resolution — the detail of the images. This is measured in display lines, typically 720 or 1080. That compares to 480 display lines in standard TV sets.

Higher resolution doesn't always mean a better image. In sets 32 inches or less, your eye can't tell the difference between 720 and 1080 lines at normal viewing distances, so there's no reason to pay for what you can't see. Even with larger screens, you may not be able to tell the difference unless you're sitting too close for comfortable viewing.

That said, the "i" or "p" after the resolution does mean something — at least in terms of price. The "i" stands for interlaced, and it refers to sets that redraw every other line of pixels with each frame. The "p" stands for progressive scan, which means the set redraws every line in each frame. Logically, a progressive scan produces a more detailed image, but many viewers are hard put to tell the difference between 720p and 1080i.

The latest and most expensive sets have 1080p resolution, but there's no broadcast or cable signal with resolution that high. The only way to get a 1080p signal is to play a new high-definition DVD movie on a new HD player. Which leads us into the next question.

• What kind of high-definition DVD player do you recommend, Blu-ray or HD DVD?

Neither — unless you want to take a chance that any high-definition movie you buy now will be an orphan down the road. This is a great time to wait.

A bit of background: Although standard DVDs provide a much better picture than videotape or standard TV broadcasts, they're still designed for traditional TV sets with 480 display lines. They can't take full advantage of the resolution of new HDTV sets. So equipment makers have been working on a new generation of DVD players.

However, instead of agreeing on a single technology, the major players are staging a bad rerun of the Betamax-vs.-VHS battle of the early videotape era. This time, the stupid war is between Blu-ray and HD DVD.

Sony, which lost the VCR wars in the 1980s, developed the Blu-ray standard, while Toshiba (backed by Microsoft) is the leader of the HD DVD gang. Each side has tried to line up movie studios to issue titles exclusively in its format, which forces consumers to make a bet each time they buy a disc. Stupid, stupid, stupid.

Is there any real difference? Not much. Blu-ray players are definitely more expensive ($400 and up vs. $200 for a low end HD DVD). Blu-ray discs hold more data but they're also more expensive to make, because they can't share production lines with standard DVDs.

In terms of enjoying a movie, there's no difference — they're both great. I also know this will enrage techies from both camps who are sure their player is better. Take your fight to the parking lot, guys.

There's no reason to get involved in this. If you want to make your existing DVDs look better on HDTV, stick with your current player or spend $100 on a standard machine that will "upconvert" regular DVDs to provide enhanced images on HDTV sets. You won't get true high-def, but you'll enjoy it until the marketplace settles on a winner and players become a lot cheaper.