High definition TV latest arena in studios' cyber piracy battle. (Media & Technology).

You know that high-definition television has arrived when Viacom Inc. and Walt Disney Co. threaten to yank their HDTV programming from the airwaves unless they get their way.

The tantrum has been years in the making, but boiled over this month because the Federal Communications Commission invited debate on the "broadcast flag" -- a technological barrier sought by Hollywood to prevent TV viewers from copying or sharing digital TV programs outside their home.

Last month, Viacom declared that its CBS Television Network will halt all broadcasting in high definition for the 2003-2004 television season unless a broadcast flag is implemented by "Summer 2003." Disney and the Motion Picture Association of America filed more muted threats the same day.

Hollywood fears that its over-the-air programming will be "Napsterized" or redistributed widely on the Internet unless the federal government steps in. But advocacy groups say adoption of a broadcast flag could restrict the public's fair use of copyrighted material.

The big entertainment companies have their sympathizers in Washington on anti-piracy concerns, but hardball tactics could backfire. Congress has mandated that all TV stations switch from analog to digital transmission by the end of 2006, to free up spectrum for other uses, and FCC Chairman Michael Powell has goaded all parties involved to comply quickly.

"I don't think this is a great time to say you're going to withhold programming. They're playing with fire," said Yankee Group senior analyst Michael Goodman, who contends that Congress has "already spent the money they expect to get from this spectrum. That revenue is built into their budget assumptions. They're not going to allow Viacom to throw a monkey wrench."

Nevertheless, Viacom's ultimatum grabbed attention because its CBS Television Network was an early champion of HDTV and offers all 18 of its prime-time comedies and dramas in the HD format.

Disney's ABC Television Network airs an average of 14 and a half hours of high-definition programming in primetime per week. In its comments, ABC said it might be forced to shift its "high quality digital programming" from free broadcast to cable or satellite systems with conditional access unless an acceptable "protection scheme" is adopted.

What better time to publicize the feud than around holiday shopping time? In electronics stores, shoppers ogle the full-wall displays of digital TV sets with tantalizingly clear pictures and CD-quality sound. Although top-end sets cost more than $7,000, some DTV monitors have tumbled below $1,000.

About 3 million U.S. households have acquired DTV monitors since sales began in 1998, but only 15 percent to 20 percent have purchased the converters needed to receive high-definition programming, according to Yankee Group market research.

The Consumer Electronics Association predicts that sales will jump to 4 million DTV units in 2003 and 10.5 million in 2006.

In its FCC filing, Viacom raised the specter of rampant piracy in homes equipped with both digital receivers and broadband Internet access. Viacom cited Forrester Research projections that 40 million North American households will have high-speed Internet access by 2004.

"Viacom believes that DTV sales and broadband subscriptions have reached the "tipping point" at which it can no longer afford to expose its content to piracy," the company declared. Without a "broadcast flag regime," Viacom contends that anyone receiving digital broadcast TV signals on a set-top box with unprotected digital output "is capable of distributing the television content to millions of people all over the globe through peer-to-peer file mechanisms, through e-mail, or through a Website."

But the FCC has received hundreds of comments from individuals and organizations that take issue with Hollywood's claims.

The Electronic Frontier Foundation ridiculed the notion that the typical American consumer can redistribute high-definition programming. Most of the unauthorized video content found on the Internet is of inferior quality, the San Francisco non-profit organization said.

"The reason is that high-quality video files are simply too large to redistribute over the Internet using consumer-grade Internet connections," the Electronic Frontier Foundation told the FCC, claiming it would take a consumer "at least 40 hours to download a single two-hour movie in HD format."

If anything, "consumers may see less bandwidth before they see more, as major Internet Service Providers are considering 'metered' pricing plans to control their bandwidth costs," the non-profit remarked.

Some consumer groups accuse Hollywood of trying to undo the Betamax decision of 1984, when the Supreme Court held manufacturers harmless for the recording of copyrighted material from commercially sponsored television. "Since that day in 1984, the presumption has been that consumers are entitled to the 'quiet enjoyment' of consumer electronics and information technology products, even though these products may potentially be put to uses that a court might find to infringe copyright," said the Home Recording Rights Coalition.

Pity the FCC, if the agency tries to plant a broadcast flag at the spot where "quiet enjoyment" ends and piracy takes off.