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Applications in interactive TV

After decades of promises, predictions, hype and experimentation, it appears that the technology, standards and content for the bundle of ideas collectively known as interactive TV have sufficiently matured and integrated to begin powering up a $20 billion annual enterprise.

This year will likely see a tidal wave of press, promotion and new buzzwords for the services and technologies involved. It's time to sort out the flavors and decode some jargon so that broadcast engineers, managers and the public can surf this promotional tsunami effectively.


The concept of interactive TV is nearly as old as television itself. In the mid-1950s, a Saturday morning cartoon called “Winky Dink and You” promoted a kit, available in toy stores, that included a transparent sheet to place over the TV screen for drawing. During every episode, children watching the show were asked to place the sheet over the screen and connect numbered dots to form a bridge, train or airplane that Winky needed to get away from the bad guys. Of course, most kids couldn't wait for the kits, and marked up the TV screen itself with crayons. An army of mothers ran to the toy stores in a panic, and the kits sold by the thousands.

Later efforts at interactivity yielded some experience for developers, but not much value for American viewers. The technologies used were thinly developed and too expensive. Delivery networks provided little real market penetration beyond a few experimental communities, and many of the offerings appeared to be solutions seeking problems. One success, however, was the widespread deployment of Teletext in the UK and many other countries. Using the vertical blanking interval (VBI) of analog TV to deliver digital, viewer-selectable text information, Teletext has become an integral part of TV viewing outside the United States. The primary American use for this technology has been closed captioning.

The turn of the 21st century has seen a convergence of development in the underpinnings of interactive TV. Satellite and cable networks now have a substantial customer base, and they have furthered the cause of niche programming begun by PBS affiliates. Viewers have come to expect a widening diversity of programming. Standards are being implemented and trials have given content producers a more sophisticated feel for the market. But the most powerful enablers for iTV have been the Internet and CD-ROM. While these interactive tools are not identical to iTV, they provide some useful examples of technical protocols, marketing and production techniques. The five top companies in iTV — OpenTV, Liberate, Canal+, Microsoft and PowerTV — are expanding their marketing efforts in the UK and Europe, which have a substantial lead over the United States in the field. With all these factors now in place, the real marketing flood is about to wash over us.

The door

The Electronic Programming Guide (EPG) or Interactive Programming Guide (IPG) is the portal application for all iTV offerings on a service. These menus allow the viewer to select programs, set times for local recording, and go on to increasingly specialized or personalized choices. They are also key components for advertisers. By tracking the clickstreams on these menus, advertisers can quickly develop a precise and personal t-commerce profile. This valuable information can make advertising much more efficient and give viewers more customized choices as the system learns their preferences.

The next iTV area is generally referred to as enhanced TV. Its content features Web-like hyperlinks that appear at various times and places on the screen. These displays can move, and they can be opaque or semi-transparent. Such digital services use device-centric broadcast HTML to mix the displays with the MPEG video stream. Hypervideo displays can also offer forms on which viewers may enter information for online purchases.

These clickable mechanisms bring about several more iTV concepts. Individualized TV allows users to alter the outcome of a drama, to personally select cameras on a sports event, or to select answers to questions asked by an instructor. As with the initial EPG, advertisers can read the user input during programs to create personalized advertising. Predictive Networks has developed sophisticated personalization software for following viewer preferences. Its “Digital Silhouette” technology can track individual viewing habits for targeting advertising data without collecting or storing personal information. Personalization and privacy concerns are a significant part of iTV development. A recent report by the Carmel Group on TV personalization can be found at

Video on demand (VOD) has proven to be a solid iTV success. Although it is fairly expensive to deploy, a number of experimental market trials have proven that it will become a staple of any iTV system. Also popular is near video on demand (NVOD) in which broadcast channels are used to make a specific set of movies available at fixed time slots.

To date, the VCR has been the ultimate instrument of personal video scheduling. But a new piece of hardware known as the personal video recorder (PVR) has advanced the idea of personal TV. The device has a large hard drive that allows simultaneous viewing and recording. It also automates recording by program title, time slot, rating, actors or theme. Removable disks for these devices are currently in development. Some of the active vendors are TiVo, Replay, Echostar, WebTV and Pace. One clear trend is the union of these PVRs with set-top boxes. An example of this integration is Scientific-Atlanta's plans to embed Metabyte's MbTV software into its Explorer 8000 PVR. Together with Scientific-Atlanta's interactive television navigator, the software is expected to automatically recommend programming, including advertising, that matches each subscriber's viewing tastes. Pace has integrated OpenTV's middleware and Device Mosaic application technology into its Di4000 interactive cable home gateway.

Of course, delivery of Internet TV and e-mail will be a central part of interactive services. But in the iTV environment, these applications will need to accommodate a wide range of viewer input devices and desired levels of interactivity.

If you're looking for a dark-horse “killer app” in all this, a good bet is play TV. This category encompasses all forms of interactive gaming and simulation. Kids represent a major force in TV viewing and Internet use, and we can expect a huge share of iTV applications to be targeted at gamers. This segment will likely be the source of technical and programming innovation that will carry over into other areas. Potential applications for gaming and multi-participant simulation are vast and powerful. The early leader, having established a strong following in Europe with its PlayJam Channel, is Static 2358, a wholly owned subsidiary of interactive media giant OpenTV. Launched in December of 2000 on the BskyB digital satellite platform, PlayJam now claims to have hosted over a billion games. Some of its more engaging statistics indicate that over half of its players are female, and 61 percent of users are aged 16 to 34.

Bringing it home

In America, when educational television became distance learning, it gained interactivity with groups in schools but not with individuals at home. In the nineties, distance learning used Ku-band satellite distribution with a telephone conference-call back-channel. Educational networks were also offering group videoconferencing over fractional T-1 lines, but these lines are expensive, difficult to maintain and they still require participants to gather at central points for the class. Corporate videoconferencing has largely followed the same path, using meeting rooms with large screens. The Internet can combine distance learning with videoconferencing by offering video, document sharing and whiteboarding on the desktop, but acceptance and implementation of Internet videoconferencing has been very slow. iTV doesn't promise to bring new features to distance learning and videoconferencing, but it will widen the user base substantially. Distance learning and videoconferencing also share a need for higher back-channel bandwidth. Most of the services use an asymmetric back-channel where the return data path does not need to have as much bandwidth as the downstream channel. Any service using two-way video or complex simulation data will require a higher-bandwidth back-channel than those registering occasional clicks on a viewer's remote control.

One buzzword sure to be heard this year is synchronized TV. A recent study showed that the number of people using the Internet while playing a TV in the same room rose from eight million adults in 1998 to 27 million in 1999, and the number was projected to be over 50 million by the end of 2001. This explains the noticeable increase in co-promoting TV-program Web sites during the shows. These tele-Webbers combine the conventional, one-way TV experience with use of the Internet for accessing the program's coordinated, enhanced TV displays — and as an interactive back-channel to the show. Where the iTV operators supply broadband access and Internet TV, these two synchronized TV channels will be combined in the TV.


VEIL Interactive Technologies offers a different technical approach to interactivity. VEIL stands for video-encoded invisible light. On analog systems, it uses the actual video signal as a transmission medium. This offers some key advantages over systems that use the vertical blanking interval. Riding on the video signal, VEIL data can be transmitted by broadcast, cable, Direct Broadcast Satellite or home video, and it can be received by economical, chip-driven devices anywhere in the broadcast coverage area. An additional advantage is that, unlike VBI signals, VEIL data cannot be stripped out by cable operators and it works on any TV transmission format with no modifications. It works with compressed video and can even be recorded by any currently used video recording device. VEIL II is the higher-bandwidth version, and its receiver chips can be incorporated easily into TV remotes, PDAs and cell phones so that these devices can act as the interactive back-channel. Advertisers can use it to track their commercials and verify that they have run in the desired time slot. CMR, a provider of strategic advertising and marketing information, has incorporated VEIL technology into its Broadcast Verification Service to track the occurrence of television programming and commercials.

SMIL for the camera

Synchronized Multimedia Integration Language (SMIL) is a well-known Internet protocol that combines and synchronizes video, text, still pictures and sound. Recommended by the W3C in 1998, SMIL 1.0 is commonly used for Internet video streaming. SMIL 2.0 received a W3C recommendation in August of 2001. Although it has been somewhat neglected, it does work and holds potential for iTV. The biggest advance for SMIL has been the fact that RealNetworks, a leader in Internet video streaming, based its enormously popular RealNetworks G2 Player on this technology. In doing so, it has kept SMIL in the Internet spotlight. SMIL presentations, including hyperlinks, can be incorporated into DTV broadcasts to provide enhanced TV. There are also economical, easy-to-learn authoring tools available for SMIL presentations. Long touted as the tool for “bringing TV to the Web,” SMIL, or a form of it, could reach even greater acceptance by doing just the opposite — bringing the Web to TV. Veon, of Herzliya, Israel, has contributed significantly to the development of broadcast HTML for Hypervideo applications. Veon was acquired by Philips in April of 2001.

Global TV

One interesting programming shift that iTV will carry among its convergent technologies is the ability of local entities to broadcast to a global audience while local cable operators field requests for international programs — some featuring automated translation. Our increasingly global economy and mobile population will eventually drive the market for international programming to and from local communities.


The most significant factor that has limited widespread implementation of iTV applications has been the absence of worldwide standards for transmission and content enhancement. To deal with this problem, several iTV industry groups are at work on standards. These include Digital Video Broadcast - Media Home Platform (DVB-MHP), Open Cable Application Platform (OCAP) and Advanced Television System Committee DTV Application Software Environment (ATSC DASE). Asia, Europe and South America have implemented the DVB-MHP platform, while groups in the United States and Canada are developing OCAP and ATSC DASE. A common thread in these efforts has been the inclusion of Java technology in the quest for a worldwide “create-once, play-everywhere” environment. This goal, also described as a “write-once, play-anywhere” environment, will play a central role in standards development. In this effort, OCAP and ATSC DASE are expected to incorporate the well established DVB-MHP into their standards.

The Advanced Television Enhancement Forum (ATVEF) is an alliance of industry companies formed to develop HTML-based protocols to promote the standardization of enhanced TV for digital delivery. ATVEF is the organization that devised the technology specification that enables broadcasters to send data through the vertical blanking interval on analog systems.

This year will see more worldwide corporate partnerships and standards debate. But the tremendous revenue waiting to be mined with laser-targeted advertising will be the driving force behind vendor competition and product interoperability. In the meantime, we'll all have to learn the basics to ride the new wave of services called interactive TV.

Bennett Liles is a freelance writer and TV production engineer in the Atlanta area.