DTV Primer

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TV Buyer's Guide

Updated 7/13/07

This update has been long in coming, and with it comes a major change in approach. Rather than trying to keep up with manufacturers' myriad models, I will now only offer more general recommendations (reflecting my personal biases, of course). This in the hopes of being more help than frustration.

Announced TV models all too often are either not yet in stores, may only be carried by a limited number of retailers, or may have been superceded by a new model. TV models may show up in stores that are not listed on a manufacturer's web site.

I generally report on major manufacturers' new TV lines when they are announced, so look back over the last few months of my weekly reports for information on the latest models.

Some Background

The transition to digital television not only affected the look of the programs that we watch, but it also catalyzed a revolution in the technology of televisions.

The future ultimately lies with flat-panel technologies, but we have a ways to go before we get all the way there. In the meantime, digital TV technology has exploded in a diversity of solutions. That absolutely benefits the consumer, but creates a sometimes daunting set of choices.

This section will attempt to throw some light on what choices are out there, and offer some things to consider before you throw down your money.

First and foremost, the new digital TV standard is not compatible with the old analog standard.

The government has mandated that new TVs work with the new ATSC standard, effective on March 1, 2007. Larger TVs had to be digital earlier.

Digital/HD Programming via Cable TV

Fewer than half the people with HDTVs are now getting high-definition programming.

Virutally all new TV sets are digital cable ready to the extent that they will receive and display unencrypted digital cable channels (compressed using MPEG-2). This is like older analog TVs where you could just plug your cable into the back of the set and get your cable channels.

Unfortunately, cable systems are not generally facilitating this sort of simplicity.

If your cable system is still analog, the only digital/HD programming you'll see will be downconverted and presented in analog. About 50% of all cable subscribers are still connected to analog service. Many smaller cable systems will continue to operate in analog at least until the end of the transition (there is no digital mandate for cable systems; it applies to broadcast television). Some newer cable boxes have an over-the-air digital receiver built-in and an antenna input for reception of digital broadcast channels.

Larger cable systems that have started to distribute programming digitally may not want you to get your digital/HD programming by simply plugging a cable in. They are either encrypting their basic channels (or compressing them using a codec incompatible with your TV's receiver) or leading you to believe that you cannot get HD channels without a leased set-top-box. They want you to have an interactive (bi-directional) capability.

The FCC has initiated a rulemaking action they hope will lead to advanced digital-cable-ready TVs on the market before the end of 2008 that will satisfy the cable industry's new business model. That is, a bi-directional navigation device built into the TV that will accept a downloadable (software) "conditional access system"--that is, a security system that can decrypt scrambled channels and that will hold the key to which channels and services the subscriber has paid for. All of this new built-in technology will also permit video-on-demand, pay-per-view, interactive program guides, and a bandwidth-conserving technology called "switched digital video."

All without a set-top-box.

Until the new standards are out and incorporated into new TVs, you're probably stuck with a set-top-box--that is, if you're a cable or satellite subscriber. If you are, you might also just try plugging your cable into the back of your digital TV, set the TV antenna input to digital cable, and see what happens.

Or you could simply settle for free broadcast-network high-definition programming via an antenna.

(The FCC has initiated proposed rules that might change the cable status quo.)

Resolution

There are three main resolutions in the ATSC digital TV standard (horizontal pixels x vertical pixels): full-specification high-definition - (1920 x 1080); a lesser "high-definition" - (1280 x 720); and standard definition - (704 x 480). These are broadcast standards rather than TV set standards, and set manufacturers are not constrained to matching these numbers.

Resolutions are often shortened to the second number--the vertical resolution--but because there are several non-standard resolutions, look for both numbers. There is normally an "i" (for interlaced) or a "p" for progressive after the number, but these letters refer to how pictures are encoded and displayed, and have nothing to do with the resolution of the set.

"1080" sets should have the full 1920 x 1080 pixel resolution (that's more than 2 million pixels). This is called "full-specification" high-definition, or "Full-HD." Blu-ray high-definition movies are normally encoded at this Full-HD resolution.

Some "1080" plasma sets display at 1440 x 1080 or 1280 x 1080 or some other horizontal pixel count, thus having far fewer pixels than Full-HD sets.

I would recommend sticking to Full-HD (1920 x 1080) displays for all sets 40" and larger. You can buy Full-HD displays as small as 32," which could be appropriate for situations where the viewing distance is as short as three or four feet, perhaps in a den or home office. Full-HD is becoming the industry-standard.

720p sets often have a 1366 x 768 pixel display; the TV has to scale the input to match its non-standard native resolution. 720p sets that use a native 1280 x 720 screen can display pixel-for-pixel 720p source material. They would still have to scale (down-convert) Full-HD and (up-convert) standard-definition programming to match its native resolution. I call 720p "HD-lite" because it has fewer than half the pixels of a Full-HD display.

720p sets are suitable for mid-sized sets where you're sitting relatively far away (for example, across a living room). They're also good for casual viewing where picture clarity is not a high priority.

Standard definition TVs (480p) are what you'll likely have for small TVs (say, 26" and less, but there's no rule of course).

Aspect ratio

Aspect ratio is the relationship between the screen width to its height. The old squarish TVs has an aspect ratio of four-to-three -- four units wide to three high -- written 4:3 (or 1.33:1). The new widescreen digital TVs have an aspect ratio of 16:9 (or 1.78:1, or the width is 1.78 times wider than the screen is high).

The new digital TV standard brings with it the widescreen aspect ratio, but while all new TVs have to include a digital receiver, there is no rule that requires new TVs to have a "widescreen" 16:9 aspect ratio.

Don't assume that just because 4:3 TVs are still in stores, they will satisfy your needs over the coming years. Although there is still a lot of legacy 4:3 (squarish) programming airing today, this will change dramatically over the next few years. Widescreen programming will take over; the ATSC standard for high-definition specifies a widescreen presentation.

Widescreen TV programs that you see on you old analog set are either shown with black bars on the top and bottom of the screen, or have had their sides lopped off by the networks for their analog signals. After the end of the transition (2/17/09), analog broadcast programs will stop and everything will be digital, and virtually all newer programming will come to you in widescreen format.

If you elect to keep your analog set (or new 4:3 digital TV) after that date, the digital-to-analog converter box (for over-the-air viewing with an antenna) will give you the choice between black bars or cropping the sides of the picture.

Manufacturers of smaller traditional-CRT technology TVs are still selling many new small digital models with the squarish screens because they have adapted older analog TV designs to comply with the digital tuner requirement. It's cheap for them, but they're no bargain for you.

Digital connections

Look for an HDMI input jack if you want to get the best quality signal from a high-definition satellite or cable box, or from a high definition Blu-ray Disc player. You'll need at least one. Two or even three may be better. HDMI version 1.3 interconnects will allow the best quality sound and picture; these will start showing up in products in 2007.

So . . . What TV to Buy?

There are four main types of televisions on the market now (I am considering only TVs with digital tuners and widescreen displays):

1) Direct-view cathode ray tube (CRT) - this is the traditional TV; sizes range from about 26" to 30". These are just about extinct in the widescreen models, and you don't want the narrow-screen ones. Prices on similar size LCD flat-panels have dropped so much that the heavy and bulky CRTs can no longer compete, despite excellent picture quality.

2) Flat-panel TVs - now available in either Liquid Crystal Display (LCD) or Plasma; common LCD sizes range from about 19" to 52", common plasma sizes from about 42" to 60". Both go much bigger, if you have a suitcase full of money.

Under development are the highly anticipated, but legally-mired Surface-conduction Electron-emitter Displays (SED), and further-in-the-future Organic Light Emitting Diode (OLED) sets.

3) Rear-projection TVs - now available in LCD and DLP varieties; sizes range from about 42" to 70".

4) Front projectors - are for serious home theaters. They require a separate screen, but that screen can have a diagonal measurement up to about 10 feet (why fool around with inches?).


Flat-panel TVs

The first big flat-panel TVs that came on the market were plasmas (in the late 1990s). They weren't terribly bright, the contrast ratio was low, the colors looked washed out, and the first set I saw cost $22,000. But they were very cool! It was the stuff of science fiction movies--TVs hanging on the wall. And at their price points, they were a status symbol.

Thankfully, the technology in plasma sets has dramatically improved (but still has a way to go) and their prices have come way down, so having that status symbol on the wall is no longer so painful on the eyes and bank account.

The dominant flat-panel technology today, however, is LCD (Liquid-Crystal Display).

Liquid Crystal Displays

What LCDs give up in mystique (almost everyone's computer has an LCD display) they take back in technical performance. Full-specification high-definition LCD TVs (having 1920 x 1080 pixels) are common. Plasma sets capable of 1920 x 1080 resolution are just starting to hit the market.

LCD TVs dominate the entire widescreen TV market up to about 42", and seem set to take over in larger sizes as well--up to 52".

As a result of the March 1, 2007 requirement for digital tuners in TVs smaller than 25," there are now many more small LCD flat-panel TVs.

As for LCD flat-panels' performance, they're very good now and getting better. And prices have been falling fast, but the rate at which prices are dropping is slowing. Expect excellent deals this fall. Leading LCD brands are Sharp, Sony, Samsung, and Toshiba.

Plasma Displays

Plasma TV makers have been undergoing a consolidation process as some TV manufacturers have dropped plasma displays and the remaining companies are fighting to keep market share. The plasma market has been close to flat and is forecast to continue losing ground to LCDs.

There is no denying that the better plasma sets look good, though, but LCDs tend to have brighter and sharper pictures. If you are committed to plasma and are serious about the video quality, you should look for one of the new plasmas with a 1920 x 1080 pixel display. In 2006 there were only a couple, but this year you have a better selection.

Pioneer and Panasonic are probably the best plasmas.

Future Flat-Panel Technologies

There are two other flat-panel technologies in our future. The first that was supposed to arrive was SED (Surface-conduction electron-emitter display), a technology being developed jointly by Canon and Toshiba, based on patents held by a Texas company Nano-Proprietary.

These sets have been demonstrated and are very impressive, giving the picture of a CRT display but without its drawbacks. 50,000:1 contrast ratio, 1 ms response time! It promised to be superior to everything else we have today. Commercial introduction of 55" sets had been set for 2008, with limited production putting some sets on sale in Japan in 2007.

Unfortunately, arrogance and perhaps greed led to a legal dispute between Canon and Nano-Proprietary and ten years of development went up in smoke. Maybe we'll see it (eventually), maybe we won't.

Further away but no less intriguing is OLED (Organic Light-Emitting Diode). This technology will share many of the benefits of SED, but will also be capable of being produced on thin flexible plastic. You could roll up your TV or wear it on your coat! Sony is going to market a very-expensive 11" OLED set later in 2007.

Rear-projection TVs

Rear-projection TV (RPTV) sets are the grand-daddys of big-screen TV. The first RPTVs used three separate CRT "guns" (red, blue, and green light) reflecting off a mirror onto the back of a fresnel screen. These CRT sets have pretty much disappeared.

RPTVs are perhaps not as sexy as flat-panel displays, but they are big and affordable and capable of displaying an excellent picture. The smallest is about 42". The largest common size is 65", but they go bigger. Full 1920 x 1080 resolutions are common on sizes 46" and larger.

The newer-technology RPTVs are often called micro-displays because they use small semiconductor chips that control the intensity and color of light for each pixel, thus creating the picture.

With RPTVs, viewing position can be an issue. Screen brightness can change, depending on your location. It's more sensitive to changes in vertical position. Your eyes should be at the same level as the middle of the screen. If you're having a big Superbowl party, for example, and some people are seated and some standing up, the standing viewers will not see the same brightness as the more optimally positioned viewers. If you always watch from the same (seated) level, this characteristic should not be a problem. Decide if this is going to be an issue before buying.

Digital Light Projection (DLP) RPTVs use a micro-mirror chip; electrical signals cause tiny mirrors to move (flutter), reflecting the proper amount and color of light onto the back of the screen. DLP RPTVs typically use a single micro-mirror chip. Check out www.dlp.com for a more complete tutorial, with illustrations.

Some of the newest DLP RPTVs use an LED array instead of a high-intensity white lamp (with spinning color wheel) for the light source. Advantages are fast start-up, more saturated colors, cooler operation, and the LEDs are supposed to last as long as the TV (the conventional light bulbs need periodic replacement at a cost of a few hundred dollars).

Popular manufacturers of DLP sets are Mitsubishi and Samsung.

Liquid Crystal Display (LCD) RPTVs typically use three LCD chips, one for each color. Besides plain vanilla LCD RPTVs, there are variants, eg. D-ILA, and LCoS.

Manufacturers are working hard to develop breakthroughs in their respective LCD technologies. There is not a single "LCD" technology, but rather companies that design and build their own LCD RPTVs develop their own variations.

Sony perhaps defines this class with their "SXRD" flavor of LCoS (Liquid Crystal on Silicon) LCD variation.


Front Projectors

Front projectors have been getting better and a lot cheaper, and therefore more popular with people looking for really big pictures. They require a little bit of work to install and properly set up, but if you're up for that, or happy to pay someone to install your system, you can get the genuine home theater experience.

With big screen sizes, 1920 x 1080 is a must.

Look at Sony, Panasonic, Sharp.