Broadcasters getting ready to take their digital signals live might envy the advantages Sid Caesar had in the heady days of live television.
Those were the days when a performer's every miscue was beamed into living rooms across America. As co-host of "Your Show of Shows," Caesar was known -- even loved -- for his television slip-ups. The rubbery comedian fumbled lines and stumbled onto sets. Doors often didn't work, and sometimes scenery collapsed. Instead of lamenting the glitches, Caesar used his wit to exploit the mistakes. Most viewers thought it was part of his schtick.
The 26 broadcasters scheduled to go digital in November won't have that luxury. They will have to live up to promises television audiences have heard for nearly a decade: beautiful, movie-theater-quality pictures and sound, more programming choices, and access to a new set of digital services.
The rich pictures and expanded services are supposed to whet consumer appetites for a new generation of television sets -- boxes that initially will cost from US$2,800 to $8,000 -- and get them to send their analog sets to the scrap heap.
But US broadcasters may have bitten off more bandwidth than they can chew.
Stations are having to build new studios from scratch and either create new material or convert existing material for digital broadcast -- and without the essential tools. Much of the technology needed to produce digital television has yet to be invented. Broadcasters are having to develop video editing and titling equipment, special effects instruments, and playback machines as they go along.
Analog equipment is fully mature and easily replaceable. Broadcasters have backup systems, so audiences rarely have to stand by while engineers overcome technical difficulties. There are no such safety nets for digital television.
The first runs won't be pretty, and broadcasters know it.
"You could have a broadcaster that goes off the air for an hour," says Craig Tanner, executive director of the Advanced Television Systems Committee, the authoring body of the digital television standard in the United States, Canada, South Korea, and Taiwan. "This could happen a lot in the early days of digital television."
The debut of digital television is the ultimate high-wire act of the digital age. Broadcasters won't be able to joke their way through when a picture goes fuzzy. Audiences will not accept losing a signal as part of the show.
It all comes down to eyeballs, and there won't be that many watching when digital television first clicks on.
"There's a zero billion dollar marketplace out there," Tanner says. "So how much are broadcasters willing to invest up front for the first thousand viewers?"
Going digital
Television is one of the few household appliances that has yet to shed its analog skin. Watches, clocks, phones, stereos -- even coffee makers -- are digital. It is part of a natural progression that, for television, is still being defined.
Certain things are known: The move to digital television will mean more elbow room on the airwaves. Broadcasters will be assigned the same amount of frequency as they have for analog -- 6 MHz -- but digital signals can be compressed to take up a fraction of that, allowing stations to split one channel into four and play multiple programs simultaneously, send one resolution-rich movie, or provide entirely new services, such as interactivity.
"Maybe you download a number of international papers during the news or some additional entertainment information," says Jeff Klein, co-president of Complete Post, a Los Angeles-based post-production house. "You have this interactivity, but it's unclear what you'll do right now because none of [the uses are] invented yet."
The methods for sending such a broad range of content along the same piece of spectrum haven't been invented yet, either.
Whatever broadcasters send over the airwaves, there will be more of it. Digital television combines CD-quality audio and movie-quality video, both of which generate files so dense with data they cannot be transmitted over the airwaves without digital video and audio compression.
"Until compression technology was in place and working, it was ludicrous to try [sending a digital signal]," says Lynn Claudy, senior vice president of science and technology for the National Association of Broadcasters.
Digital programming will travel the way computer data does over a network, in packets. The packets will be compressed using a combination of AC-3 and MPEG-2.
It's possible that the same size slice of bandwidth now used to transmit a single analog program could transmit an HDTV movie or as many as four standard digital programs simultaneously. As such, it could be a tool for the networks to compete with cable.
"In [Los Angeles], you can have 10 TV stations with digital delivery systems on all 10 channels," explains Gerry Kaufhold, principal multimedia analyst for Cahners In-Stat Group. "On this, you can deliver 45 programs at once.... So if the cable industry isn't nervous about this, they will be."
Delivering the digital future
Digital studios will have to be built from the ground up. The basics include a new antenna and digital transmitters, which can cost $1 million, according to Tom Gurley, vice president of technology for Maximum Service Television, the testing laboratory for digital TV equipment.
The minimum investment will allow stations to broadcast network, not local, digital content. To produce original content, Gurley says a broadcaster will have to shell out between $5 million and $10 million to put together a full complement of equipment: digital cameras, editing machines, and playback machines.
"There's not enough equipment in all of LA to produce enough HDTV material to fill all of prime time," Klein says. Broadcasters and post-production houses are having to invent the technology as they need it.
That wouldn't be such a problem if broadcasters could concentrate on one issue at a time, Kaufhold says. But, in the United States, digital TV is a broad definition that mixes the conversion to digital with a change in the display format (HDTV). The combination has given broadcasters too much to juggle at once.
"There is a significant glitch because we've tied digital TV to a new display format," Kaufhold says. "Any engineer will tell you that's a bad idea."
For example, in Europe and the Far East, broadcasters are converting their analog signals to digital. They are having to build new studios. But once they determine that the new antennae and transmitters work properly, they'll be able to broadcast five standard programs on a single channel and have a ready-made audience. Most of their viewers already have sets that can receive the signal, Kaufhold says.
In 1996, US broadcasters and computer makers agreed to use their respective screen technologies in the development of digital displays. As a result, there 18 possible formats, depending on the resolution and the method for scanning a screen.
Resolution can range from 640 by 480 pixels for standard definition digital television to 1080 by 1920 pixels for HDTV. Screens can vary, too.
Televisions use interlace scanning, where a screen is created line by line, while computers use progressive scanning, in which an entire screen is scanned at once.
Such details raise sweat on the brows of the engineers producing content for digital TV. "The equipment we have [for digital TV] works for one resolution or another, but not multiple resolutions," says Klein at Complete Post.
Engineers already are having to invent the equipment they need to create digital content in different formats. Beyond that, they have to adjust their editing to accommodate different resolutions. Post-production houses have to do the work because the four networks -- ABC, CBS, NBC, and FOX -- are using three different video formats.
Keeping so many balls in the air increases the potential for disaster, Kaufhold says. "You just change one variable at a time. We're changing six variables, and it's now a mess."
Forget everything you know about TV
The early adopters of HDTV will be expected to invest in costly new sets. But they'll have little to show for their money, since broadcasters have made limited commitments to digital content. CBS, for example, plans to offer five hours of HDTV content per week in prime time once digital broadcasts begin in November.
There are quality problems as well. Snow and double images are familiar analog interruptions, but digital TV comes with its own set of disruptions: Frozen jumpy frames or areas of the picture that are blacked out. One viewer might have no signal, while a neighbor across the street has a gorgeous picture. Broadcasters don't really know what viewers will get, Kaufhold says. It's all a crap shoot.
"You can sit down to watch an [analog] ballgame and deal with the fact that there are twice as many people on the field," says Gordon St. Clair, chief technical supervisor for multimedia developer Blastorama. But the glitches in digital television "make you insane. It's absolutely unwatchable."
Please stand by
"No one has shipped a million digital televisions, so no one knows if they really work, " Kaufhold says. "It worked in the lab, but if we turn on in LA, we have no way of knowing that some bug might come out and bite us."
In other words, roll-out of digital TV amounts to one big beta test.
"Over the next 36 months, there are going to be adjustments ... some bumps and forks in the technology road where we'll have to sit down and say this part doesn't really work," Kaufhold says.
At the end of the 3-year period, the kinks should be worked out and digital television will be ready for mass consumption -- if there is still an audience left.
Kaufhold says the two big obstacles to digital television are the fact that television already exists, and the fact that it works. When television was first invented, no one had anything to compare it to.
Digital television is largely an untested technology, as television was in its early days. But those days are gone.
"Everybody under the age of 50 has grown up with TV," says Kaufhold. And everybody under the age of 50 has high expectations of how television -- digital or not -- should work.
"If I turn on my digital TV at noon and it doesn't work, and I'm comparing it with my old TV and it works, then the new technology doesn't look so good," says Kaufhold. "If you're going to sell this new TV set, it better work."
