Current.org | A preview of the DTV experience, May 1998

WGBH experimented with DTV-like interactivity with its Zoom pilot. Click on the orange icon and get instructions for making a balloon-powered toy car. Click on another icon and you download a computer game that lets you play with the car's physical principles. (Image courtesy of WGBH.)

What will DTV be like?

We can see precursors, but not exactly where it's going

Though standards for digital TV have been negotiated in hundreds of expert meetings over the last eight years, many aspects of the DTV experience will now be decided by the marketplace.

Manufacturers' guesses about consumer tastes will determine, for example, how DTV sets will list programs and channels in the on-screen program guides that people increasingly will use to find programs and set their VCRs.

Broadcasters' views of the market will decide what kinds of non-video and interactive services will be aired.

And consumers will vote at Best Buys whether the focus remains on high-definition sets or shifts to lesser and cheaper forms of DTV. That will also help resolve the broadcasters' loudest debate so far--the format choice between 720-line progressive-scan and 1080 interlaced.

When network execs repeated the format debate in a House telecom subcommittee hearing April 23 [1998], CBS Chairman Michael Jordan observed: "The noise and confusion you are now hearing is the sound of that marketplace at work."

Though the Advanced Television Systems Committee (ATSC), which includes broadcast, computer and electronics companies, has been developing recommended standards for years, it hasn't yet adopted some important specs, with less than six months before the first stations sign on.

Many firms didn't devote major resources to the tasks until the FCC allotted the channels, and DTV became "a real thing," according to Bernard Lechner, a former RCA Labs exec active in ATSC work. "There's been a tremendous increase in the effort to tie down loose ends."

Only rough outlines of the DTV experience can be seen so far, but it's resembling earlier media devices, with navigation like direct broadcast satellite (DBS) systems and injections of interactivity like Web TV.

No longer the universal Tube

Instead of being a universal Tube that serves rich and poor alike in much the same form, the DTV set will present new options for varying budgets and tastes, like stereos and computers.

"There will be many more differences in capability from set to set, because the capabilities are so vast," says John Tollefson, PBS's chief technology officer. "There's room for tremendous diversity of opinion."

Many of the first sets will be two-piece modular jobbies, says Richard Green, a onetime PBS technical chief who since has headed CableLabs, the cable industry's spec-making unit. A "set" will include a receiver box, which can be replaced as technology changes, plus a more costly monitor, which can be used for many years.

The receiver box increasingly will also serve as the cable box, Green predicts. Cable boxes already are on their way to becoming off-the-shelf products bought by consumers rather than leased from cable operators. The 1996 Telecom Act requires that option, and many cable companies want to get out of the box-leasing biz. At CableLabs, Green has led the development of the OpenCable standard that will make cable boxes interchangeable.

It's a short step to integrate the cable box into the receiver, which Green expects to happen quickly. In many cases, a single cable-ready box will stand between the cable and the monitor, receiving both analog and digital signals and outputting them as appropriate for a new DTV monitor or an old analog TV set.

The cable box will also become an enormously fast modem and possibly the access point for low-cost long-distance phone calls via the Internet.

Cable may become all the more important in the DTV era if digital reception problems aren't resolved. Experimental broadcasts show frequent multipath interference problems for urban viewers who lack rooftop antennas, as well as weak signals in outlying areas. In both cases, the DTV signal doesn't merely look bad; in digital technology, it fails completely.

"The antenna has been the most-neglected element of the broadcasting industry for 20 years," says public TV consultant John Lawson, who is a member of ATSC. He predicts there will be some "imaginative R&D," and notes that DBS companies, in their competition with cable, are talking about installing DTV-receiving antennas for their customers along with the DBS dishes.

It's still Channel 26

The most blessedly simple thing about DTV is that broadcasters will be able to use their present analog channel numbers for their DTV channels as well, even though DTV actually will be transmitted on different channels, according to Craig Tanner, executive director of ATSC.

If Channel 26 (for example) multicasts several streams on its DTV channel, the viewer will have a choice between 26.0 (the old analog channel), 26.1 (the first DTV stream), and 26.2, etc. (If Channel 26 leases out 26.4 to the local abortion clinic or terrorist organization, it can give the leased channel an unrelated number.)

Though viewers still will be able to punch the channel numbers on their remote controls, they may increasingly use cursors to zip through on-screen program guides, which at first will probably resemble the guides used by DBS services like DirecTV. On some sets, the viewer will be able to call up customized menus -- all-sports programs, or all-comedy, for example. Whether the viewer navigates with cursor keys, a trackball or the arms of an interactive Barney doll ultimately will depend on consumer tastes.

Data for the program guides will come from each over-the-air channels, which will continually transmit ATSC-standard data covering at least the next 12 hours of their schedules and as many as 16 days.

"What the receiver chooses to do with that is up to the receiver manufacturer," says Bernard Lechner. Some receivers will take the data from all available channels and create a multichannel program grid like DirecTV's. Many probably will pick up this data by scanning the channels at night, when the sets are in "sleep mode."

For cable channels, however, the schedules will be compiled by the local cable system for all of its offerings and will travel separately from the programs.

John Lawson predicts the typical on-screen program guide will feature a video window previewing selected shows and "icons that take you to a branded collection of services," such as the Discovery Communications family of offerings.

Whoever controls the program guide will not only have a promising venue for advertising sales (like Yahoo on the web), but also "a tremendous amount of power" to steer viewers, says John Carey, a media consultant who often works with public TV. A big cable company could promote channels that it owns and "put the others in the graveyard," Carey warns.

"There seems to be a lot of paranoia about that," acknowledges Green, of CableLabs. But he says cable operators will always have the incentive to list their full offerings, especially local programs. In any case, he says, problems can be negotiated as part of the retransmission agreements between broadcasters and cable.

Open-ended: the interactive factor

The interactive aspect of DTV may be the least developed so far and the most important, with huge opportunities for demographically targeted advertising, instant home-shopping purchases (and pledge-drive responses) and all kinds of program-related supplemental text of the kinds already seen in PBS Online.

Most profoundly open-ended is the option of broadcasting entire computer programs, such as program-related video games, that would run on the computer in the DTV set.

With funding from Microsoft, Boston's WGBH this winter developed the prototype of such a game to play on Web TV with the pilot of its new Zoom series. One of the prototype's most successful ideas, says WGBH's interactive chief, Howard Cutler, was a little if/then educational program about building a balloon-powered toy car that illustrates physics concepts in the episode (photo above).

But the many pop-up text boxes and interactive doodads in the prototype distracted some viewers from Zoom itself. "It's as crucial as ever to be drawing the viewer's attention where you want it, and when you want it," Cutler says now. The project also proved that software tools for writing the interactive content are crude so far, and designers lack the experience to plan the interactive interface reliably the first time around.

ATSC's DTV Applications Software Environment (DASE) group is now considering choosing Java and Macromedia technologies, among others, for the software engine for interactivity, says Chairman Aninda DasGupta, a senior researcher at Philips Research.

Though the DTV set will be a computer in many respects, DasGupta says the designers "are trying very hard to make sure they don't crash." The receiver won't allow one computer program to interfere in the memory space used by another--a major reason that computers using Windows crash frequently.

Meanwhile, ATSC's specialist group on interactive services is completing the first draft of a spec for the "session layer" that controls the connection for interactivity, says Chairman Michael Haley, a senior technical staffer at IBM.

The ATSC group recognizes that some receivers will be feeble compared to others, according to Haley, so if the broadcaster offers a digital doohickie that the DTV set can't handle, the viewer will be told the option is unavailable, or the option may not even be shown on her set--the group is now debating which way to deal with the situation.

Interactivity isn't a natural part of one-way broadcasting, of course. Its greatest potential will be filled only when there's an upstream path for viewers to send requests and responses, probably via phone line and/or the Internet.

But a lot of interactivity will be possible even without that, because DTV sets have the capacity to silently receive and store masses of data on the chance that the viewer will use it. Sets may have voluminous memory, Haley says, because RAM chips are cheap now--16 megabytes for $90.

Even if a station is airing a 1080-line HDTV signal that uses most of its available channel capacity, it would have 1.4 megabits/second left over for data--100 times the bitstream of a 14.4 modem, a stream that could fill a 16-megabyte memory in a couple minutes.

Can you see the difference?

In the picture-format dispute, NBC and CBS are betting on 1080i, the most detailed format of the 18 formats incorporated as options in the ATSC standard, while ABC and Fox favor 780p, and public TV hasn't taken sides.

Despite their differences, however, network execs at last month's House hearing assured legislators that they don't need to intervene. The debate about formats isn't a counterproductive "Beta vs. VHS" fight, said ABC-TV Network President Preston Padden, because all sets labelled "DTV-ready" will be able to receive all formats (though the less expensive sets will show the better pictures in reduced definition).

The broadcasters may have to decide, because it may be years before the public has a chance to see the differences for themselves.

The relative quality of 1080i, 720p and 480p couldn't be seen in a demo during the House hearing, for example, because everyone was sitting yards away from the screens. All the pictures looked terrific.

A problem for 1080i is that you can't see its advantage unless you're sitting fairly close to a large set, with a screen of perhaps 40 inches or bigger, says consultant John Carey.

PBS Engineering Committee Chairman Bruce Jacobs, who handles DTV planning for both North Dakota's Prairie Public TV network and Twin Cities' KTCA and personally supports 720p, says he's skeptical that consumers will accept the cost of the highest formats if they don't see screens that show the difference.

The first DTV sets will be have 1080i displays, but if consumers aren't adequately impressed by the step-up in quality, sales could lag seriously, says Bob Gerson, editor of TWICE, a consumer electronics trade magazine, and manufacturers could turn to 480-line, 36-inch receivers that would still deliver excellent, digital pictures at more reasonable prices.

Gerson notes that in Japan--the only place where the public can watch HDTV broadcasts--most viewers receiving the NHK programs are watching on sets with wide screens but less-than-HDTV resolution.