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New DTV features

Broadcasting has always been a one way proposition: what you see is what you get. Watching TV has, until now, been a passive activity. In the beginning, just seeing the moving images was spellbinding. As technology moved forward, color, then sophisticated graphics and live remote broadcasts were added. Today, viewers can even vote live, albeit via their telephones, on some programs. The quest has been to provide the viewer with as much information as possible while expanding their involvement with the programs.

Today some will say that this visual information deluge is beyond usable to the point of distracting. (Read "Lower the visual volume" from the October 2005 Editorial in Broadcast Engineering.) Have you ever been watching a news program, then catch something on the crawl, where your attention shifts to the elimination of the original program? As you wait for the crawl to return the information you’re looking for, you're miss the entire newscast.

Television viewing might be more enjoyable if the viewer could control the appearance of extra info, graphics and alerts. In other words, allowing the audience to customize their viewing experience could benefit both viewer and broadcaster.

The advent of DTV brings us to the verge of a personalized, converged, more Internet-like television viewing experience. That is, if the proper standards are implemented.

DTV standards

In 1995, when the ATTC completed tests of the Grand Alliance prototype, there was little precedent for two-way communication between viewer and content provider. The Internet had yet to take off as a consumer item. Still, the standards committee well understood the need to provide extra capability in the MPEG transport stream for datacasting and other enhanced TV features.

Emerging standards have sought global interoperability. The DVB Multimedia Home Protocol (MHP) is the DVB specification for the technical implementation of interactive TV applications. The DTV Application Software Environment (DASE) was the initial ATSC interactive enabling standard. CableLabs has their version, the Open Cable Application Protocol or (OCAP) for cable platforms. But, that leaves us, again, with more than one platform to support.

Fortunately, the ATSC A/101, Advanced Common Application Platform (ACAP) standard harmonizes the ATSC DASE and Cable Labs OCAP standards while also providing functionality for Globally Executable MHP (GEM), which apply to DVB applications. The intent is to offer an interoperable standard so that receiver manufacturers can develop interactive-capable consumer devices.

Infrastructure technology implementation

There are three types of features that DTV standards enable: enhanced features, interactive features and networked or Internet applications.

Enhanced (eTV) features are those applications that can be implemented without a back channel. Interactive (iTV) features require a back channel. Network or Internet features expand the TV viewing experience beyond the living room or immediate environment.

Enhanced features include local scenarios. Applications are downloaded to the receiver and all events are triggered by user input. The applications reside in the receiver. An EPG is an example of local interactivity.

When a back channel is available, access to remote information can be requested interactively by the user and then downloaded to the DTV receiver. An example would be a VOD movie.

Networking features and connections to the Internet are still in development. This will lead to personal home digital networks. But interoperability, security and rights management are issues that must be resolved before such applications can become a reality.

New advertising opportunities

The ability to deliver customized and targeted advertising is something all broadcasters and content providers need to think about. This is considered the "Holy Grail" of Madison Avenue. Let's look at one targeted advertising workflow example.

As with any complex project, careful planning must be the starting point, specifically emphasizing the intended end result. In this case, the goal is to promote and get the viewer to purchase a vacation package.

The client has decided to target three groups: retirees, families and couples. To sell to these three groups, an infomercial will be produced. The infomercial will be made available as VOD. Other features will include the ability for the viewer to email a link for this commercial to a friend or access the advertiser's website from the TV set. An option to locate a near-by local travel agent will be an on-screen option. Finally, the program will allow the viewer to schedule and pay for a trip — all through the TV.

The usual ad production process is followed, the ad is storyboarded and content must be produced. While some content is universal to all three audiences, there are some scenes that are unique to each audience. For the families, the video/audio may highlight group activities. For the singles, romantic locals may be key. For the retirees, perhaps the content emphasizes more relaxed and restful locations. Appropriate video is captured and returned to the post room for composition.

Now, it’s time to assemble the interactive application. First, there needs to specific icons developed, which indicate the two-way nature of the video. These must be linked to specific triggers that will launch behind-the-scenes tasks. Appropriate security must also be enabled.

To implement these interactive features, new authoring tools will be needed. These are available from several vendors, but be sure that the production tools will properly embed the needed codes and data to properly control the down-line functions that must be completed.

The "data" is fed into the MPEG transport stream multiplexer. It must be compliant with appropriate specifications such as ATSC A/90. In any case, it cannot exceed the 19.39Mb/s maximum data rate.

The video is transmitted and then received by the consumer. The television or STB now decodes the audio, video and data. Data is then placed on the DSM-CC data carousel and appropriate icons are displayed.

Inside the receiver or STB, the viewer has stored key personal information. These demographics may include information that the viewer is married and has no children. This means that when the VOD is displayed, instead of a scene of noisy children playing, a couple is shown at some romantic get away. The ad concludes with a viewer-activated lower-third graphic with contact information for the nearest local travel agent based on the viewer's zip code.

Let's say the viewer is interested in receiving more information. She clicks on the information icon. In an OTA system, the Directed Channel Change (DCC) PSIP feature is activated. Based on the viewer's profile, the DCC jumps to a relevant looping infomercial on an SD multicast subchannel. Or, with a cable STB, a specific VOD could be launched.

Finally, the trip is booked and the Television-commerce (T-commerce) transaction is securely completed. A link to this ad is forwarded via email to a friend whose 10th wedding anniversary is coming.

Sound far fetched? It's not. All that's needed is to connect the various pieces of the data technology puzzle and broadcasters will have developed an entire new class of profit-making services.

Making contact

Unfortunately, until ACAP/OCAP/MHP-capable receivers are available, interactivity, targeted advertising and T-commerce will be limited to STB implementations.

Samsung demonstrated the first ACAP-ready HDTV, in conjunction with Aircode, a Korean company specializing in DTV-related iTV and commerce applications, in the DTV Drafthouse at NAB2005. Set-top boxes from vendors like Motorola and Scientific-Atlanta are already OCAP capable.

Traditional broadcasters must adapt. This is the survival of the fittest, where the consumer could vote you out of business with their dollars. Broadcasters must realize that DTV is not just about audio, video and graphics. It is about creating an interactive experience.

We'll look at some new examples of DTV interactivity in our next newsletter. If you have specific questions or comments, send them to


Enhanced TV standards: ACAP:



An in depth description of interactive technologies from a programming point of view is available in the book: "Interactive TV Standards: A guide to MHP, OCAP, and JavaTV" by Morris & Smith-Chaigneau, Elsevier, Focal Press, 2005

System diagram of an OCAP implementation by NDS:

PIMG system diagram:

eTV/iTV equipment and software suppliers

Triveni Digital Skyscraper:

Search for "MHP" and click on "CORAL" items.

Packet Vision:

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