MHEG Complements Interactive TV

Valerie Thompson

Hypertext Markup Language (HTML), Java, and the Web are taking the world of interactive applications by storm. But there are areas where these technologies fall short.

A couple of international multimedia content producers and set-top box manufacturers -- Philips Business Electronics, Sony, and Nokia among them -- are currently evaluating the new ISO standard 13522-5 for multimedia distribution. Called Multimedia and Hypermedia Information Coding Expert Group (MHEG), it is a self-contained hypermedia architecture that can run in environments with very small resources, such as set-top boxes whe re Java-enabled browsers are an overload. Although it was originally developed for broadcast applications, MHEG has some substantial advantages for information and point-of-sales terminals as well as interactive TV.

Testers report that, in contrast to HTML, MHEG relieves the server load because it transmits complete scene information only once to the client. It employs an object-oriented model, generic enough to format different kinds of multimedia documents, and provides on any network the quality of service people expect from TV. In addition, it offers powerful models of spatial and temporal synchronization between different media, which are not provided for in other standards.

For developers of interactive TV the quality of service that MHEG offers is the main issue. "Failure is not an option. Here you cannot tolerate GUI crashes or unresolved references," said an engineer at Philips Business Electronics (Eindhoven, The Netherlands).

Currently, there are two mature authoring tools for MHEG-5. One, based on Asymetrix's ToolBook, was developed by DeTeBerkom (Berlin) and Grundig Multimedia Solutions (Nuremberg, Germany). The other uses Macromedia's Director and was designed by CCETT, France Telecom's R&D institute.

Several companies and research institutes have developed MHEG run-time engines. The Digital Audio Video Council (DAVIC) has chosen MHEG as the standard exchange format for high-level applications. In the DAVIC specification 1.1, MHEG coexists with Java and can be called from within an HTML document.