A Stroll Past HDTV's Problem Areas

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Pity technology's new-again beauty, high-definition television — that breathtakingly beautiful girl at the dance, so lovely that not a single boy can muster the courage to ask her to the floor.

Everybody wants HDTV, but nobody wants to pay for it. The reaction to it is rapturous: "Mesmerizing!" "Better than the eye can see!" Yet less than three of every 100 U.S. homes contains an HDTV set.

Of those, most sets are used more to view DVDs than to tune into a growing — but still slim — amount of HD television content.

From origination to destination, and at every junction along the way, HDTV has issues. Big, techno-political issues, rooted in fear and cost — the dynamic duo of "do-nothing."

This week's translations will stroll the signal path of a broadcast HDTV transmission, with brief stops at the trouble zones. Subsequent columns will further explore the many strife points.

IT ISN'T CHEAP

Troubles lurk right from the start of an HDTV program. The first is cost: It's high, to say the least. HD-equipped TV production trucks can run north of $500,000. Transmitting an HDTV show costs in duplicate staff and resources, because it doesn't naturally supplant existing analog broadcasts.

Also omnipresent is the bulk of the HDTV signal. The extra information that justifies the high-definition label is plump — so much so that two HDTV channels can barely wriggle into the bandwidth used by 10 of today's digitized cable channels. Yet bandwidth is not infinite or free.

When an over-the-air HDTV signal arrives at a cable headend, it needs processing known as "re-modulation." That's because sending stuff through the air is harsher than sending it over a wire. (Anticipating this, and adding information to compensate for it, is another reason HDTV signals are so stout.)

As a direct result, broadcasters use a method called "vestigial sideband," or VSB, to convey signals. Cable uses QAM, or quadrature amplitude modulation.

Engineers say it's not a big deal to remodulate from VSB to QAM. Being realists, though, they usually add that any signal conversion can introduce problems.

And then there's the consumer side of HDTV, where there are way more questions than answers, and the answers are hiding within unresolved arguments. Most, if not all, of the in-home HDTV problems have to do with the set itself. Is an HDTV set the same as a digital TV set? And for that matter, what's digital about a "digital TV," as described by consumer-electronics and retail stores?

In these nascent, confusing days of HDTV, many consumers think they already own an HDTV set, but when the cable installer gets there with an HD-capable set-top box, they learn otherwise.

It seems that "digital," as an adjective, is as watered-down as "new and improved," especially when it comes to HDTV.

Part of this descriptive problem links to a decades-old argument of surprising intensity, given the blandness of the protagonists: Connectors. Yet it is precisely at the "gozintas" of HDTV that things get ugly.

FIREWIRE AND DVI

In a huge oversimplification, there are two types of connectors that feed HD signals into HD displays: Analog and digital. Of the digital, there are also two types: Firewire, also known as IEEE-1394, and "DVI," for "digital visual interface." (DVI also has a next-generation version known as HDMI, for high-definition media interface.)

Firewire makes it easy to daisy-chain more electronic things to the HDTV set, like a digital video recorder. This, of course, makes Hollywood queasy — not to mention vocal — about rights management and copy protection.

Firewire also caps the types of advanced graphics that can accompany a show, because its speed capabilities, while fast, aren't fast enough for HD graphical overlays.

DVI solves those problems, but it precludes the attachment of the other stuff that consumer electronics companies would like to sell, which makes them
unhappy.

And though they're less of an issue now, the matters of resolution linger, which further muddy the understanding of HD. These are the "720p" and "1080i" tags that describe lines of resolution, and how they're painted on the screen.

WHICH WAY TO 'REZ'

But wait, there's more. Questions also linger around the notion of adapting a digitally encoded show from one resolution to another, often referred to as "up-rez'ing" or "down-rez'ing" an HDTV image. To "uprez" is to add detail that wasn't in the original, standard-definition digital picture. It's like trying to make a pineapple upside-down cake from two twinkies and a can of fruit cocktail.

Why care? Why now? Because if you work for one of the top-10 U.S. cable operators, you're part of a commitment to deliver five HDTV channels, including broadcast transmissions, next year.

After 20 years in the making, it's starting to look like the most tangible change in television since color may finally get its turn on the dance floor.

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