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High-Tech Times Article 015

High-Definition (Television (HDTV) Information

With our computer technology accelerating as fast as it is, it seems a bit surprising to realize that the television we watch today isn't really very different than the technology used since the mid-1950s. Well, that's about to change.

On April 4, 1997, the Federal Communications Commission awarded 6 MHz (or 19.3 Mbits/second) of frequency spectrum to each of approximately 1,500 television stations for Digital Television (DTV) broadcasting. By doing so, the FCC opened a whole new era for TV watchers and computer users alike.

They decreed that the three commercial networks in the top 10 U.S. markets were to start broadcasting digitally by May 1, 1999, with markets in the 11th through 30th spots coming online by November 1, 1999. All U.S. TV stations must broadcast digitally by May 1, 2003, as the current analog TV spectrum is scheduled to revert back to the FCC on January 1, 2007. Somewhat unfortunately, the FCC decree did not specifically define DTV, and, in fact, lists 36 possible formats for digital transmission.

This lack of definition is now the battleground between the TV networks and the computer industry. And at stake in this war is (1) how soon DTV will deliver high-definition content to those who do not buy DTV sets, and (2) whether your DTV will sport the familiar Microsoft Windows and Intel logos.

Let's start off with some basics. Your current television screen shows an analog signal that is strictly mandated by the National Television Systems Committee (NTSC). This signal has a standard resolution of 512X486, a 4:3 aspect ratio (screen width:height), and a frame-rate of 30 frames each second (actually 29.97). When you go to the movies, you're seeing much higher film resolution and a wide-screen 16:9 aspect ratio at 24 frames/second (FPS). DTV is intended to give you about the same quality as the movie screen in the comfort of your own living room.

Three parameters define each of the new DTV formats: resolution, scan type, and frame-rate. Four resolutions are acceptable to the FCC: 1920X1080, 1280X720, 720X480, and 640X480. The first two resolutions are called High-Definition (HDTV), and the last two are called Standard-Definition (SDTV).


Scan type refers to progressive scan versus interlaced scan. Current NTSC video is interlaced: each of the 29.97 frames that make up each second of TV video is split into two fields, odd and even, that are interlaced together. Computer monitors are progressive-scan devices, where every line of the entire frame is updated from top to bottom, at a rate determined by a combination of your video board and the monitor's internal specifications.

The last DTV variable is frame-rate, or the number of times the screen is updated each second. Each resolution supports multiple frame-rates and scan types. For example, 1920X1080 supports 30 FPS in both interlaced and progressive modes, as well as 24 FPS in progressive mode.

Backing the 1920X1080 interlaced (1080i) format are CBS, NBC, Sony, and Warner Brothers. They believe DTV should be as close as possible to the same quality as the 35mm film you see at the movies, wide-screen and all. The first problem with this approach is that we will need a big-screen TV, which could cost $5,000 or more, and may leave some viewers without the deep pockets to buy them. Second, the 1080i signal uses the entire 6 MHz allocation, which leaves no room for other digital content.

The other DTV team consists of Compaq, Microsoft, Intel, Lucent, ABC, and Fox, which supports the 1280X720 progressive (720p) format. This format allows plenty of spectrum bandwidth for other digital content, which can be another channel, Web-based content, or data multicasting (showing both HDTV and SDTV). The second advantage is that computers can easily support 720p DTV with minimal upgrades (around $100). This could dramatically increase the number of DTV viewers near-term.

So, our first choice appears to be better-quality content (1080i) that few people can afford, and that offers none of the other perceived benefits of digital transmission. The real unstated benefit of 1080i seems to be maintaining the apartheid of computers and TV sets...and keeping Wintel out of the living room. Our second choice (720p) promotes again unstated computers as the preferred viewing devices, giving Intel and Microsoft a huge advantage over the television manufacturers.

To add to this confusion, the Motion Picture Association of America (MPAA) is worried that converting all video and audio content to computer-compatible digital data will cause their clients (all the major producers of movie and TV programming) a world of hurt. One popular proposal for early adopters of DTV is to use a digital cable into a low-cost "set-top box" that will then be connected to your TV via a familiar interface: FireWire, or IEEE-1394. FireWire is already the standard for camcorders, digital VCRs, and DVD players, to name a few.


So suppose some pay-per-view service offers a new hit movie, and you, the consumer, use your FireWire connection to record that movie to your new DVD recorder. Then suppose you loan your copy to two of your friends, who in turn make digital copies, and so on until everyone has a copy, with only you having paid for it. MPAA has used this horror story to convince Congress to pass legislation that called for copy management in consumer digital audio recorders, which is why DAT has never become a consumer success.

And of course there is no guarantee that DTV will become an overnight success story, either. In 1965, 11 years after NTSC color TV was introduced, only about five percent of the U.S. had a color set. But by 1975, that number had rocketed to over 75 percent. So will broadcasters give us a reason to buy DTV sets? Will they commit to providing significant coverage of multichannel surround-sound, data-enhanced interactive programming, and digital-quality super-hits?

No one knows, but there a lot of companies betting the farm on it.