"When we designed and developed the concept for Cyberchase our goal was to develop a project that worked in multiple platforms," said Cyberchase Executive Producer Sandra Sheppard. "We saw it as a model for convergence. We created a TV show that is adventure driven and we wanted to give kids an immediate opportunity to participate in a related adventure, activity, game, or puzzle online. The goal of Cyberchase is not only to encourage kids to think about math in a different way, but to be able to experience it."

Enhancing Cyberchase
In the past two years PBS has developed interactive TV trials for two adult contemporary programs: Scientific America Frontiers and Life 360. Cyberchase was chosen as the third iTV trial to see how children relate to an interactive environment.

"When we were approached to create enhanced versions of Cyberchase we were pretty far along in our process in terms of the television series," said Sheppard. "We really didn't have the opportunity to say we're going to start from Day One and develop a truly interactive experience that works both as linear and interactive television."

Due to the problem solving nature of the series, Sheppard believed that Cyberchase was a perfect candidate for the iTV trials, but cautions other producers before they make the leap to this medium: "You first have to think about whether the program that you're creating works as an interactive experience. I think it's pretty tough to do it with a narrative. You don't want to take away from the experience of the drama and kids in particular are very immersed in the story. In terms of actually developing a series, in order to develop scripts that serve both purposes, I think you have to do it in tandem with someone that works in the interactive world. It's a different mindset and a very collaborative process."

The ten enhanced episodes of Cyberchase were transmitted over both analog and digital signals. In analog, viewers need to use a back-channel Internet connection to retrieve interactive data. An icon pops up on the television screen to let viewers know there is an enhancement and they can dial up to the Internet to retrieve it. The problem is that it can take time to retrieve the enhancement and if information needs to appear at an exact time during the show, it's just not possible.

A digital signal differs in a number of ways since it can transmit up to 19.4 Mbps. According to Jonathan Schembor, vice president of Customer Services, Triveni Digital, "The 19.4 Mbps can be sliced and diced anyway a station wants to." So instead of having one channel per analog line, it's possible, depending on what rate the digital program is encoded at, to have four or five channels running on one 19.4 Mbps channel.

Additionally, though it's not two-way interactivity, it allows broadcasters to "push out" more data than is possible over an analog signal.

PBS chose Triveni Digital's Skyscraper as the interactive DTV broadcast system for Cyberchase. Schembor noted that the real strength of the DTV signal lies in its ability to take data and embed it directly into the DTV stream: "Our mechanism allows you to not even need a back channel. We actually send the enhancements with the audio/video over the airwaves where the set-top boxes (STBs) receive them. Those STBs pull out the video and the data is cached locally on the STB. When the trigger says, ÎI want to show you this enhancement at this frame,' the data is already there and the enhancement is synchronized to the second."

Organizing The Troops
The interactive Cyberchase focused on open standards and was authored for a wide range of platforms including WebTV and UltimateTV. The enhancements were received and stored in ATVEF-compliant STBs. "ATVEF is a relatively basic presentation engine that is effectively a browser," said Schembor. "It's being used through the television rather than the computer and it happens automatically. The browser is embedded within the STB."

The key to the whole process, said Deron Triff, senior director, PBS Interactive Television, is advanced planning to minimize variations between the platforms that were being used. "We used the Chyron Lyric authoring software tool, which allowed us to export to multiple platforms to accommodate the various ways that the content is presented on the STB. Once a template was created, the tool digests the template and you literally do two clicks to export files to various platforms. There are folders that reside on the servers here at PBS that store the content on each of the various STB combinations. And we had a browser sniffer that recognized the box and rounded the appropriate overlay to the right box. It would have been difficult if we hadn't thought it through in advance and we hadn't identified which boxes we were targeting."

PBS Interactive, Thirteen/WNET, and ExtendMedia worked closely to coordinate the interactive episodes of Cyberchase. A new script for the interactive portion of each episode was developed working in collaboration with the same content advisors and writers for the television script. Brian Brunius, interactive television producer, Thirteen/WNET said, "We had to identify open slots in the show script where we could add our extra content. There was a long process of designing what that interface would look like and making it work on quite a few platforms."

ExtendMedia created a base template for the program using a screen overlay on top of the television program that looked like the video window the three young animated characters use in Cyberchase. ExtendMedia created standard interactive features such as the ability to customize the outline or overlay to a favorite character, bios of the characters, and facts and trivia questions. In addition, math problems were programmed to appear at specific times during the shows.

"We did all the creative input and a lot of the writing with support from WNET and its math experts," said Scott Wassmer, senior project manager, ExtendMedia. "And then we did the technical implementation. Cyberchase was viewed on a number of platforms. We had to create the code and the programming to be able to run on all the different platforms. We did both the analog and digital signals. They differ in the way that they're programmed and the way that the layout is finally rendered. Specifically, with the digital feeds, the layout is set up so that everything is one graphic and that graphic is overlaid on top of the program whereas a lot of the analog feeds are cut up more like an HTML page."

Triff believes the true growth potential for DTV is in multicasting and interactive program-related data. At some point, he said, video assets will be used within schools on a regular basis. "Schools can combine program clips that adhere to the state curriculum standards and stations can insert local data around national video clips or programs. This is an effective way to get an interactive learning module that can be sent to the school and reside on a video server. Teachers can pull out relevant clips and match those clips in a much more customized way to their teaching."