DVB: Forgotten, But Not Gone


As the National Association of Broadcasters prepares to
convene and ponder what digital TV hath wrought upon that industry, it's invigorating
to imagine a digital-TV transition scenario in which the cable industry really sticks it
to terrestrial broadcasters.

For example, cable could adopt a renegade technology that
makes the retransmission of DTV all but technologically impossible.

Uh-oh: That's pretty much what cable has accomplished
with its quadrature-amplitude-modulation approach to DTV -- not a cozy companion to the
broadcasters' ATSC vestigial-sideband (actually, eight-level VSB) format.

So here's another idea: What if cable adopted the
forlorn Digital Video Broadcasting format, which is embraced almost everywhere on the
globe, except North America?

Well, actually, one key competitor -- EchoStar -- uses
DVB-S (the DVB satellite version) for its feeds, but that's a different story.

And anyway, the U.S. cable industry shot down the DVB
standard -- also known as ITU-A (as approved by the International Telecommunications
Union) -- years ago. Goaded by General Instrument, most cable companies embraced the
so-called ITU-B format.

Only one large MSO -- MediaOne -- has embraced DVB. And
will anyone know -- or care -- what MediaOne prefers after Comcast absorbs it?

Hence, by general consensus, DVB is dead in the U.S. today.
Those who want to stir up a battle -- making North American ATSC (Advanced Television
Systems Committee) vs. European DVB analogous to the NTSC vs. PAL incompatibility of the
past four decades -- are being ignored.

Since ATSC and DVB are both based on MPEG-2 technology,
they share a common heritage that comes in handy for digital services.

There are a few other technological differences among the
world's digital TV standards. Most notably, North America is using Dolby AC.3 for
audio coding, while Europeans are using Musicam (MPEG Layer 2). All of this is resolvable.

Of course, the DVB crusade continues elsewhere in the
world. Brazil, China and Singapore are still deciding whether to adopt ATSC or DVB as
their digital-TV broadcast format. Their choices may affect world hardware production
volumes and prices, since the same iron mongers (equipment vendors) are pursuing the
global marketplace.

What makes all of this particularly interesting is the
receiver and programming ends of the equation. Since DVB, ATSC and cable's QAM MPEG
preferred formats are all transmission technologies, the real challenges will be in
program encoding and reception.

But it appears that the technologists have resolved most of
the problems on this front. The Common Image Format takes the viable area of programs and
allows them to be adapted to whichever system the carrier uses.

Obviously, the continuing cable vs. terrestrial battle
involves the final steps of the transmission. If it must retransmit broadcast ATSC digital
shows, cable prefers to pull in the programs, to convert the VSB signals to QAM at the
headend and to send that downstream.

Broadcasters (at least some of them) want VSB signals to go
all the way to the household, but MSOs continue to argue that VSB may be OK for
terrestrial transmission, but it is not efficient for bandwidth over cable.

And that's the most interesting factor of the entire
process. As study after study has grudgingly concluded, viewers just want good pictures.
Few will care about the tech spec that they see, but they'll certainly blame the
cable operator (or satellite carrier) if the picture quality stinks.

In any case, the DTV-to-cable issue, along with the
picture-quality factor, continues to make all parties wonder about what kind of digital
mess they've gotten themselves into. At last month's Digital Engineering
Conference -- orchestrated by the Consumer Electronics Manufacturers Association -- the
debate raged.

Among the prospects was the idea that consumers will have
to use DTV as a "component service" -- the big screen (be it 16-to-9 or 4-to-3
ratio, or any other configuration) will be bought and used separately from the set-top box
or boxes, while the long-life display component (10 years or more) would be fed by a $300
or $400 digital-control console that could be upgraded every few years.

Of course, that arrangement would overhaul the economics of
the consumer-electronics industry -- especially if it relied on cable, satellite or other
carriers to call the shots about what kind of signal was actually getting into the

"The set-top box is an 'unnatural act,'
visited on the consumer," opined CEMA's top engineering officer during the
heated conference session.

By the time the DTV issue is resolved, quite a few more
unnatural acts will have been committed.

I-Way Patrol columnist Gary Arlen counts from zero to one,