Broadcast engineers chat among exhibits at Iowa symposium, 2008

Broadcast engineers chat in the exhibit hall at this year's Iowa DTV Symposium. (Photo: Current.)

Details: There’s simply nothing simple about DTV

Though TV has been creeping headlong toward digital broadcasts for two decades, and we’ve known for more than two years that next Feb. 17 [2009] will be the end of analog TV, it seems there are still a lot of details left to be dealt with.

There will be DTV pictures that are way too little for the screen, for example, and sounds that blast much too loud, until engineers bring them under control.

In the meantime, viewers will confront annoying details of hooking up their receivers, and broadcasters face taxing details in the transition that could foreclose some of that public annoyance.

“We’re off on a lot of high-detail kinds of things,” says David Felland, director of engineering and operations at Milwaukee Public Television.

Speakers pointed to more than a few such particulars last week at Iowa Public Television’s 14th annual Iowa DTV Symposium. With 430 attendees and three days of panels in Des Moines, it was the event’s largest edition yet—and the last one before DTV becomes the only kind of broadcast TV we still can get.

“We’re working just to keep the signals from going dark,” said William Check, senior v.p. of the cable industry’s National Cable & Telecommunications Association. In that kind of situation, details can get set aside for later attention.

For many stations and viewers as well, the DTV transition is rolling right along. Of about 364 pubTV stations in the country, 355 were pumping out DTV signals as of Sept. 11, by PBS’s count.

Americans are buying 32 million DTV sets this year, the Consumer Electronics Association says, and half of households already have them. The people who had never heard of the DTV switchover has dropped from 60 percent in 2006 to 2 percent this spring, according to surveys by the Association of Public Television Stations.

CEA President Gary Shapiro, speaking in Iowa [long MP3], was determinedly sunny. DTV converter box sales are “going phenomenally well,” he said. He acknowledged there would be “a little bit of confusion” in February. “Losing TV for a day or two is not going to kill you,” he said.

Details in setting up DTV

But others saw worrisome details in the shadows of the early analog shutoff for most stations in Wilmington, N.C., Sept. 8.

“For a lot of people in Washington, it was a real wakeup call that this is not going to go smoothly,” said Harry Jessel, editor/publisher of TV NewsDay [MP3], at the conference.
Extrapolating from Wilmington’s clueless callers to the national scale, he said, “that’s 3.4 million people who are going to have real trouble when they wake up Feb. 18.”

Several speakers liked the idea behind the so-called Nightlight bills, introduced by Rep. Lois Capps (D-Calif.) and Sen. John Rockefeller (D-W.Va.), which would permit another month of analog broadcasting just for DTV education and emergency info. After the switchoff, Wilmington broadcasters could still reach former viewers and tell them how to acquire a set-top DTV converter box.

Bill Hayes, organizer of the Iowa symposium and director of engineering at IPTV, rejected simplistic efforts for DTV education. “This is a very technical conversion, and we’ve tried to make it look not too technical,” he said. On Nov. 6, the Iowa network will demonstrate TV hookups on a live primetime call-in show. Among other things, viewers will learn “why indoor reception sucks, compared to outdoor reception,” and when antennas are needed. There’s nothing simple about it. Hayes has acquired 35 models of converter boxes and says “they all behave very differently.”

Instructors must remind viewers to enter channel numbers both by automatic scanning and manual entry of the numbers on new DTV sets or boxes, said David Donovan, president of the Association of Maximum Service Telecasters. Sometimes a channel number must be entered manually because the automatic scanning skips over it. At that point, the viewer must know the actual FCC channel used by a station, not the one that appears in cable guides.

Donovan and others like regional “soft tests” that simulate the analog switchoff without actually turning off the transmitters. Those tests require close coordination with cable operators; viewers could be even more deeply confused if a cable operator carried a fake analog switchoff that should be experienced only by over-the-air viewers. It’s bad enough that some are asking how to plug their over-the-air converter boxes into cable.

Dan Ullmer, chief engineer of commercial WECT/WSFX in Wilmington, said some viewers are troubled by the lack of battery-powered DTV converter boxes for emergency use. He noted that such a box is now sold by the Winegard Co. in Burlington, Iowa.

It’s not always easy to find a converter box of any kind at local retailers. Hayes visits Iowa stores frequently and finds converter boxes in stock only 20 percent of the time — and even less often in rural areas.

Phil Swann [MP3], an HD expert who issues predictions annually, attributed the sparseness of converter boxes to retailers’ conflict of interest. The government mistakenly put sales in the hands of stores that would make more money if they could sell a new DTV set instead of a cheap settop box, he said. “It doesn’t take much to figure out that.” The remark offended Shapiro.

Donovan the broadcaster and William Check of the National Cable & Telecommunications Association spoke up for closer and sooner coordination between stations and their local cable operators. Donovan said the most important DTV receivers in town are the ones at cable systems’ headends, which pick up the signals seen by most American viewers. Check urged cable operators to order the new digital gear they’ll need, including demodulators, decoders and antennas, as well as receivers.

Details in sight and sound

It took decades for engineers to tame analog TV, Hayes says. The pictures on early TV sets rolled every time the director switched cameras, but a whole generation since then has never rushed to twist the vertical hold knob. Technicians polished down TV’s rough edges by adding circuits over the years.

You already may have seen the “postage-stamp” picture, one of the sad sights coming to your TV monitor: a puny video picture with generous black bands above, below and on both sides, hogging most of your new HD flat screen.
    Somewhere in the transmission chain, someone took a widescreen show with the new 16:9 screen proportions and created a letterbox image, adding black bars on top and bottom to show its full width on the traditional 4:3 screen. Then someone else put this letterbox on a real 16:9 display, which adds black bars on the sides.

The Advanced Television Systems Committee developed Active Format Description as part of its DTV standard to stop such screwups. The program’s original producer knows whether it was shot with the important action protected in the center, for example, and can attach an AFD code alerting users that the picture’s sides can be cropped off for showing 4:3 screens without serious damage, Hayes says.

“The problem is, it’s not quite ready yet,” said Donovan. Not every producer puts the AFD metadata into its programs; not every network plans to cooperate; not every cable operator pays attention, and not every set-top box has the circuitry to detect it.

“To have proper AFD codes can’t happen too soon,” said Felland. He hopes PBS is on schedule to begin using the codes in December. The network plans to send out programs in their native format, Hayes says, along with AFD metadata so that the receivers know the shape of things.

Hayes wishes the ATSC standards-setters had put more mandatory “shall” verbs behind AFD and fewer cases of the optional “may.”

AFD is especially important for viewers who, for at least three years more, still will be able to buy analog service from their cable operator. For those viewers, that’s the only DTV receiver that matters, Hayes says, is the one at the cable system that converts the signal back into analog. If the cablers don’t pay attention, they could cut off the sides of a letterbox image, leaving the tiny “postage stamp” picture.

Comparable details need fixing in many aspects of digital TV, including its sound.

In analog broadcasting, an entire audio processing industry arose to prevent too-loud sound from overmodulating a transmitter and prompting an FCC fine, Hayes says. But loudness carried in a digital signal doesn’t cause excess in the airwaves, so the FCC doesn’t care. Home-theater viewers may actually want to hear the full dynamic range from dinosaur footfalls to the tenderest notes in a symphony. Most broadcasters won’t want to sound feeble compared to their competitors. Cheesy advertisers use audio processing to produce the loudest-seeming ads that don’t break FCC rules. And some DTV receivers will have no protection.

As a result, Hayes says, “there’s nothing to stop them from blowing the hell out of speakers.”

Nothing that time won’t fix all over again.

Web page posted Nov. 3, 2008
Copyright 2008 by Current LLC

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