Driven by the ambitions of their developers, computers have carved out an increasingly prominent role in music, games and other forms of home entertainment. But they haven't made much of a dent in the domain of the King Daddy of the living room, the TV set.
There are many reasons for that, starting with the comfort gap between an office chair and a La-Z-Boy. Another factor is that TV signals often look blotchy and grainy on a computer screen.
The advent of digital TV, however, might give viewers a reason to reconsider--particularly if their TV set can get at least a passable picture using an indoor antenna. A few companies have released plug-in cards that can deliver crystalline high-definition TV pictures to a PC screen for a fraction of the cost of an HDTV set.
At about $400 per card, these are not idle purchases. Nor do they make TV viewing on a PC more comfortable. But they can use a PC's intelligence to deliver more features than digital TVs do today, such as the ability to pause a live broadcast or chat online with other viewers.
Of course, there's no reason to buy an HDTV card if there's nothing you want to watch in HDTV. The major broadcast networks have gradually increased the supply of programs shot in high definition, but they've yet to offer any HDTV exclusives. You'll merely find HDTV versions of movies, dramas, sitcoms and sports already in the lineup.
The richest vein of HDTV is on satellite TV, where HBO and Showtime offer multiple movies daily in high definition. None of the plug-in cards on the market today can tune in to satellite broadcasts, however.
The best over-the-air source is CBS, which has converted virtually its entire prime-time entertainment lineup as well as one soap opera, "The Young and the Restless." The next frontier, said Executive Vice President Martin D. Franks, is expanding its HDTV sports broadcasts beyond the Masters golf tournament, college basketball championships and pro football playoffs.
Beyond that, the networks and public broadcasting offer what amounts to a few hours of high-definition programming per week, mainly in the form of movies and specials. Their only regularly scheduled HDTV broadcasts to date are "NYPD Blue" on ABC and "The Tonight Show With Jay Leno" on NBC.
No cable companies in the Los Angeles area, and few around the country, carry HDTV signals. To watch those programs on your PC, you'll have to tune in to broadcasts through an antenna, ideally one on your roof or in your attic.
Digital TV signals are all-or-nothing affairs: You'll either get a perfect picture or a blank screen, depending on how strong a signal you receive. If you can get at least a passable conventional picture with rabbit ears, chances are good that you'll get a perfect digital signal with an indoor antenna.
Two companies offer HDTV plug-in cards for just under $400, both of which work only on computers running Microsoft Windows: AccessDTV and Hauppauge Computer Works. A third, BroadLogic Network Technologies, is developing a card for other companies' advanced TV services.
The cards work best with recent-vintage computers that can receive data at high speeds from their plug-in slots. That's because HDTV signals contain an immense amount of data--more than 19 million bits per second.
A trial run with an AccessDTV card in a new Dell desktop PC found that it had some of the same strengths and weaknesses of a HDTV set, only on a smaller screen.
The card came with an indoor antenna, which worked best when mounted high and pointed at the signals' source. Inside a downtown Los Angeles office building, all it could manage was the occasional frozen image from one digital channel. But in an Atwater Village house, it pulled in digital signals from all the major network stations and many of the independent channels.
Once the card locked on to a signal, the picture was extremely sharp and detailed--so detailed, in fact, that viewers could detect the makeup on actors' faces. It was a dramatic improvement over the picture displayed on a conventional TV set nearby, which also used an indoor antenna.
The HDTV standard also calls for 5.1 channel surround sound. The AccessDTV card can pass on those signals to a surround-sound amplifier, but it can't transmit sound directly to speakers.
The card also included software for recording shows and replaying them as they're recording, a feature found on digital recorders from TiVo, ReplayTV and UltimateTV. Viewers can pause a live broadcast to take a phone call or grab a snack, then resume without missing any of the show. They also can replay segments of a show as it's being broadcast.
These features caused the test PC to crash multiple times, however, especially when trying to fast-forward through recorded programs. That problem might have stemmed from the PC's original video software, which AccessDTV urges users to update to avoid conflicts with the card. The typical hard drive can't hold much HDTV--each hour requires 9 gigabytes of storage space.
For $10 per month, AccessDTV will supply a customizable program guide through the Internet that can be used to find and schedule recordings. But the guide doesn't identify which shows are in HDTV--for that information, you'll have to consult the Web sites for HDTV Galaxy (http://www.hdtvgalaxy.com), which is free, or HDTV Magazine (http://www.ilovehdtv.com), which charges a one-time $35 fee for its daily updates.
Some TV manufacturers argue that consumers can't really appreciate HDTV unless they see it on an oversized screen. When viewed from the typical distance of a PC monitor, however, the difference between HDTV and conventional TV is striking even on a 19-inch screen.
That's not to say that the experience offered by a PC card is as rich or enjoyable as one on a 50- or 60-inch projection HDTV. But those sets start at $3,500 to $4,000, or 10 times as much as the plug-in cards. For those who crave HDTV and don't care where they watch it, that difference is striking too.
Times staff writer Jon Healey covers the convergence of entertainment and technology.