At issue is how to create interactive enhancements in a studio or at a cable or satellite headend, and how to maintain the integrity of that content through production, transport and distribution. Interactive content must be decoded exactly as intended on a viewer's digital set-top box or digital TV receiver, or it won't fly in the market.

The International Telecommunications Union (ITU) has set a deadline of early November for fixing on an application programming interface, while the Society of Motion Picture and Television Engineers (SMPTE) wants to complete a production protocol by September. Both initiatives will play out against the contentious tangle of business and technology interests of studios, service providers, TV manufacturers and software companies. Every one of those camps wants, of course, to call the shots for each consumer's interactive TV experience.

Stakes are high, since the authoring platforms agreed upon by studios and transport companies, such as cable and satellite service operators, will ultimately determine the substance and rendering power inside a digital set-top box or DTV receiver. Similarly, a certain set of APIs favored by box builders could influence the types of authoring tools production houses can use.

Meanwhile, studios appear to prefer one type of programming environment—using only a so-called "declarative enhancement language" such as HTML—to quickly add enhancements to their core TV programs.

Cable operators or satellite companies, on the other hand, are leaning toward a different programming environment, one using a so-called "application execution engine" like Java to preserve control over the look and feel on a screen.

"There is a complete divergence" among interactive platforms currently in use or in development, observed Michael Dolan, a consultant at Digital Television Consulting (Alpine, Calif.), whose clients include DirecTV, and "no critical mass" behind any one of them.

Tower of Babel
Besides the contenders offered up by companies and consortia—including the Intel-Microsoft Advanced Television Enhancement Forum (ATVEF) spec and the U.S. cable industry's OpenCable specification—are the national darlings: the DTV Applications Software Environment spec from the U.S. Advanced Television Systems Committee (ATSC); Japan's DTV spec, developed by its industry forum, called ARIB; and the Multimedia Home Platform from Europe's Digital Video Broadcast (DVB) standard.

"If the Disney or Discovery Channels wanted to add any interactive enhancements to their core audiovisual programs for global distribution, they would have to author them in eight different ways," said Dolan. "The programming companies won't put up with this."

Jim Hart, the chief engineer at Channel Four Television in London, called the proliferation of platforms "an inhibiting factor" for his company and others that are seeking to move into interactive content distribution. "It is terrifying," he said.

In the U.K. market alone Channel Four already faces the burden of tailoring programs for a few diverging formats. Interactive content would have to be delivered on the OpenTV platform of the BSkyB satellite operation and in the MHEG format for On Digital, the U.K.'s terrestrial digital TV provider, in addition to developing Channel Four's own Web services.

Citing a requirement to pay BSkyB six figures in British pounds per year for the use of the OpenTV platform, Hart said, "We have provided no interactive content for BSkyB yet."

Meanwhile, division is also the order of the day in terms of settling on a forum for resolving such issues. Many European service providers, regulators and system vendors who attended the World Television Forum here earlier this month are putting their money on international standards organizations—the ITU-T (telecommunications) and ITU-R (radio communications) bodies, in particular. But some U.S. companies that are keen to start enhanced TV programming, such as Microsoft, appear to favor the SMPTE initiative. The idea, according to observers, is to get a plan finished done in September, ahead of the ITU's decision in November.

More specifically, the ITU, through separate working groups under ITU-T and ITU-R, is aiming for resolution on a common API for the three incompatible digital TV standards as currently defined by the United States, Japan and Europe.

"We are very close to coming to an agreement to harmonize APIs between DVB's MHP [Multimedia Home Platform] and the U.S. CableLabs-initiated OpenCable," said C.P. Sandbank, the broadcasting technology adviser for the United Kingdom's Communications and Information Industries Directorate, part of the Department of Trade and Industry. "There is a very strong possibility that a large part of DVB's MHP will become the ITU recommendations."

Skeptics abound
Yet many executives remain skeptical about efforts by ITU-T Study Group 9 (of which Sandbank is a member), working on common APIs for cable operators, and ITU-R Study Group 6E, which is hashing out similar API issues among global terrestrial broadcasters.

"By the time things get to ITU, it's usually too late," said Jerry Bennington, the secretary of ATVEF and a consultant to CableLabs. "ITU does not necessarily resolve anything."

Meanwhile, Dolan is heading up a due-process committee called D27 within SMPTE, which is working to develop production specs for both declarative (HTML) and procedural (Java) "data essence." Data essence is data that is neither an audiovisual stream nor metadata, of the type usually created for program enhancements.

As more digital TV programs begin adding interactive content, "We are seeing the impedance mismatch between authoring standards and transport standards such as ATSC and DVB," Dolan said.

Under those two digital TV standards, matters like Dolby Digital audio and MPEG-2 video streams are well defined and understood by set-top boxes. But once a studio or a cable headend adds interactive content, "you can't just assume that [it] can be properly decoded and rendered on a receiver," Dolan said. "How do you know whether a receiver has an HTML or Java interpreter?"

Java, in fact, is emerging as a key issue within all three groups working on programming and production—ITU-T, ITU-R and SMPTE D27. Each must decide whether to permit the use of Java as the core element for the multimedia-programming environment.

At the ITU-T Study Group 9, most participants appear to have agreed on positioning Java at the core of the spec. The issue being debated now is "how to build hooks to HTML and XML," said Jose Tejerina, the Study Group 9 chairman. SMPTE's Dolan cautioned, however, that while Europe's MHP sees Java as "the only underlying theme" for interactive content programming, not everyone in U.S. broadcasting agrees.

"We don't see Java is the answer at all," affirmed Wendell Bailey, chief technologist for advanced broadband technology at NBC Inc. The network of Friends and ER, a founding member of ATVEF, sees HTML as "the only available thing today," Bailey said. NBC is moving ahead to build enhancements using HTML, he added.

In reality, the lack of easy-to-use Java tools makes it impossible for studios or production houses to "add, on the fly, any interactive data elements in Java to a live broadcast of sports event [today]," observed Dolan. But the market could soon solve the tools that gap.

"I'm not sure whether that's a problem [lack of tools] that is going to last for a long time," said Edward Caleca, senior vice president of PBS Technology & Operations.

And Dolan noted that "Program enhancement or layout control can be preserved with both declarative [HTML] and procedural [Java] content."

'Timing is critical'

As the squabbling over API and interactive TV production standards roars on, some industry leaders are getting impatient. "Standards are set by markets, not by standards bodies," Skip Pizzi, technical manager of worldwide television standards and strategy at Microsoft, said at the World Television Forum here in early June. "Timing is critical."

Besides the lack of tools, the intellectual-property rights issue associated with Java is a roadblock for anyone seeking to embrace Java with open arms, warned ATVEF proponents. "Look carefully where the DVB folks stand on Java. They have yet to iron out final licensing agreements with Sun in writing," said Bennington of the ATVEF and CableLabs. Another executive close to ATVEF said, "It's not like we don't like Java. But when things come to the issue of control, you have to understand that Sun's Scott McNealy is as difficult as [Microsoft's] Bill Gates."

Reached last week in Brussels, Carter Elzroth, who chairs a DVB committee on intellectual-property rights, said that "supersetting Java" is one outstanding issue remaining in the group's discussions.

"We are talking about the ability of clean room implementers—those who developed a clean room Java according to the published Java spec, but without Sun's license and without Sun's test suites—to implement MHP, with other functions beyond MHP, in Java name space." Lawyers for DVB members continue to thrash out the issue, he said, and "we believe we will have answers at the next DVB steering board committee [meeting]." It is scheduled for later this month, Elzroth said.

Within the SMPTE's D27 group, the Intel-Microsoft-led ATVEF format is making deeper inroads. D27 activities are divided into two phases, carried out by separate groups. An ad-hoc group is working on the development of Declarative Data Essence (DDE), while a study group is planning to produce a report on Application Data Essence (ADE).

The DDE group has already put together a specification based on ATVEF, ready for the first ballot next month. Meanwhile, the ADE study group is hoping to come up with "at least a framework" for authoring program enhancements. Dolan confirmed some overlap in the current activities at ITU and SMPTE on API issues.

He said that SMPTE's D27 group is hoping to "provide technical foundations on these issues in a somewhat independent manner from ITU." Traditionally, ITU depends on external bodies to develop specifications, rather than inventing new ones on its own, he added.