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IT issues on 666 ABC Canberra Drive with Keri Phillips each Monday at 5:50pm

Tom Worthington With Tom Worthington FACS, Visiting Fellow, Department of Computer Science, Australian National University

"Interactive TV": 1 October 2001

What is it? When will we get it? How have Canberra geeks been hacking into it?

This week with Louise Maher

Last week I presented Internet-TV Convergence with the Multimedia Home Platform at the Communications Research Forum, sponsored by the Department of Communications, Information Technology and the Arts :

Australian free-to-air broadcasters have recently adopted the European Multimedia Home Platform (HMP) as the Australian standard for interactive TV. MHP is based on Internet and web standards and so offers compatibility and convergence between TV and the Internet. Nevertheless, MHP is a complex standard of more than 1440 pages. An overview of the main points of the standard, and its compatibility with the Internet and opportunities for convergence of content are discussed.

Here is a less-technical summary of the talk:

What is the Multimedia Home Platform (MHP)?

The Multimedia Home Platform (MHP) attempts to adapt existing Internet and web standards for to digital Television (DTV). The aim is to provide interactive digital content that can be viewed on set top boxes and multimedia PCs. MHP is intended to operate with satellite, cable, terrestrial and microwave systems.

June 28, 2001 First MHP applications for digital TV

First MHP applications for digital TV The first MHP (Multimedia Home Platform) applications for digital TV are now available. Watch a streaming video demonstrating the use of a browser in digital TV. The video was made by recording the video output of a MHP capable set-top-box.

From: Sonera Plaza MediaLab 2001

Who produced it?

MHP was produced by the Digital Video Broadcasting Project (DVB), a European-based consortium of broadcast companies and regulatory bodies. DVB Standards are published by the European Telecommunications Standards Institute (ETSI).

Where can I get the standard?

A copy of the current draft (1448 pages) is available as a 19 Mbyte zipped PDF document on the MHP web site. Work is underway to have MHP adopted in Australia, under the formal Standards Australia processes.

What will MHP be used for?

Typical uses intended for MHP are:

How is an MHP Set-Top Box Built?

Existing Internet standards are used for content including still images (PNG, JPEG), Video/Audio (MPEG-2), text/web pages (DVB-HTML) and programming (Java).

Some partial implementations are available for Windows NT 4.0 (on at least the equivalent of a 500-MHz Pentium III and 32 to 128 Mbytes of RAM). The full set of software may not be available until mid-2002.

Linux based, free open source software for MHP is likely to be available, turning a PC into a TV and digital video recorder.

The TiVo digital video recorder is an existing Linux based TV set-top-box. Andrew Tridgell, a Canberra Linux expert demonstrated how he modified a US TiVo to operate in Australia at 2001:

Modified Tivo
I got truly amazed when I found out that Tridge and friends, not satisfied with adding more hard drive space, soldering memory on the motherboard, reverse engineering the proprietary connector on the motherboard and turning it into an ISA bus, turning a Tivo entirely into a PAL capable device, they reversed engineered the video format, got video from the Tivo to play over the network on outside computers, figured out the TV guide database format and wrote programs to make their own database feeding for Australia through information automatically gathered by scripts on a web TV guide. I mean these people created a new Tivo product from the existing one before Tivo, and with no technical help or docs from Tivo whatesoever.

From: Inside Tivo, Marc Merlin, 2001

The MHP specification envisions three modes of use (profiles):

  1. An enhanced broadcasting profile: for broadcast (one way) services,
  2. An interactive broadcasting profile: interactive (two way) services,
  3. An Internet Access Profile: Internet based, or Internet-like service.

Application model

A key aim of MHP is the selection of broadcast services, by the user directly or a web-like application providing an Electronic Programme Guide (EPG). Pieces of MHP content to be presented together to the end-user can contain broadcast audio, video and data and stored material. Services can be started and stopped by others (security permitting) allowing linking together of services.


MHP uses cryptographic hash codes, digital signatures and digital certificates derived from internet standards are used. This will require an infrastructure for issuing public key certificates to identify broadcasters and viewers, with similar privacy and integrity issues as the Internet.

Internet access clients

MHP supports referencing DVB services & content on the web. That is clicking on a link to DVB content will launch the DVB service (such as video). MHP devices are required to support the "mailto" URL, allowing the user to send e-mail using an SMTP client or Web-based mail service.

Compatibility with the Internet

MHP is built from the same components as the Internet. Making an MHP device that also provides Internet access should be feasible. Web sites can be launched from MHP services and MHP from the web.

An MHP device could be produced from a personal computer with a digital broadcast card and software added. Such a device could support MHP and have good Internet compatibility. However, expanding existing DVB set-top boxes to handle MHP will prove a challenge, even without allowing for Internet access as well. Entry level set-top boxes do not contain a hard disk and so can have only limited software. Digital video recorders, such as the TiVo, may provide the early platform for MHP.

Opportunities for convergence of content

MHP provides the opportunity for thinking about the creation of hybrid works that are part web site and part live TV. This can go beyond the creation of a web site based on a TV show. Content could be written for delivery to both an interactive and broadcast audience. Some pointers to the required techniques could come from the production of educational material and from the design of computer games.

A parallel can be drawn with the Wireless Access Protocol (WAP). With the support of the telecommunications industry it was envisaged that WAP would provide an Internet-like standard on mobile devices and support for m-commerce. However, WAP required implementation of a large and complex set of standards that, while based on existing Internet standards, were not upward compatible. In addition there was an attempt to isolate users of WAP from the real Internet and its free content. WAP has failed as a product and the rival i-mode appears likely to succeed.

It is possible that simple alternatives to MHP may emerge, in the same way i-mode emerged from the shadow of WAP. As an example it would be feasible to carry multimedia content using the existing Teletext data channel of analog TV. This would provide many of the features of MHP, but at a lower cost and while maintaining compatibility with existing TV standards. Creating an Electronic Programme Guide format that could be used by MHP should be possible, in particular, web and Teletext services.

In theory the use of Internet and web standards for MHP should provide opportunities for convergence. Using common tools to produce content that can be used on the Internet should be possible and with broadcasting. Material used to construct a web site could be streamed for a broadcast. However, the differences in business models and production techniques may make convergence infeasible.

Further Information

  1. Text of talk and Slides
  2. iTV Is The Broadcast Industry's Worst Nightmare, by Craig Liddell, 2 October 2001
  4. MovieLink Internet
  5. Website Design For Information Technology Professionals, for Australian National University students, 2001
  6. More Links
  7. 666 ABC Canberra Drive
  8. Author's home page


Suggestions and comments would be welcome. Links to web sites with non-product specific advice would be most useful.

Comments and corrections to:

Copyright © Tom Worthington 2001.