Download: The Multimedia Home Platform

On Nov. 13, 2001, it was announced that Cable Television Laboratories had adopted the DVB Multimedia Home Platform (MHP) as part of the OpenCable Application Platform (OCAP). The advanced OpenCable set-top boxes will be deployed throughout North America to allow users access to both digital broadcasting and interactive digital applications.

The announcement was interpreted by some industry analysts as a bridge across historic chasms: NTSC vs. PAL; ATSC vs. DVB; cable vs. DTV broadcasting; broadcasting vs. the Internet; proprietary vs. open standards.

Have CableLabs and the Digital Video Broadcasting Project built a bridge across historical rifts as wide as the Atlantic? Or is MHP a showy exercise in futility?

As one might expect, the answer depends on who you talk to. And one cannot discount the possibility that what the industries competing for control of our digital future say may not necessarily be what they mean. A case in point: Currently, there are no plans to deploy OpenCable digital set-top boxes by any Cable MSO in the United States, nor any plans to do so by consumer electronics industry vendors who have been seeking to sell cable set-top boxes at retail, as mandated in the 1992 Cable Act.

A decade later, the cable industry continues to deploy and lease proprietary set-top boxes. CableLabs has been in the middle of a debate between the cable MSOs, the consumer electronics industry, broadcasters and Hollywood. Each time it appears that progress is being made, a new issue surfaces delaying implementation of the proposed OpenCable standard.

When this exercise began, the notion of the set-top box providing a bridge between TV and the Internet had yet to be conceived. Vice President Gore was promoting his vision of the “Information Superhighway.” AOL was just beginning to tell consumers “You have mail.” The cable industry was promoting its vision of Full-Service Networks. Charlie Ergen was talking about DBS. And the NCSA Mosaic Web browser had just been introduced, along with the concept of the World Wide Web.

Standards for interactive services

IP was still an acronym for intellectual property — Internet Protocol was virtually unknown outside of the ARPANET (the forerunner of the Internet). Today, the management of digital media content — specifically the protection of copyrights and patents — is the latest stumbling block to impede the critical path of OpenCable, not to mention DTV and the Internet.

The adoption of the MHP middleware gives OpenCable the appearance of supporting an international standard for the authoring of interactive applications. Yet even in Europe, where the MHP specs were developed, it is difficult to find anyone using them. Some of the most compelling examples of interactive television services have been demonstrated in Europe — BskyB's coverage of soccer, the BBC coverage of Wimbledon and a wide range of new digital services — most notably online gambling and video games — that build upon the legacy of analog Videotext services.

All of these services ride atop proprietary middleware; the result of a hotly contested marketplace with potentially billions at stake for the companies that persevere through the initial commercial shakeout phase. At the moment, the market leader appears to be OpenTV, but CanalPlus Technologies, Liberate, Microsoft, Sun and NDS are all vying for a piece of the action.

MHP provides an open application programming interface (API) for manufacturers to develop multimedia applications, without any third-party agreement with a proprietary middleware provider. This offers an alternative to the established way digital set-top boxes are made. Historically, STBs have been custom-built by manufacturers for private (cable or satellite) service providers and network operators. These markets have historically been closed to consumer electronics manufacturers, although they have achieved some success through collaboration with DBS service providers.

The rationale behind standards such as OpenCable and the DVB standards suite, both of which now include MHP, is to allow open competition in the STB markets. In theory, competition would benefit consumers in much the same way that the unbundling of telephones led to a proliferation of products with feature differentiation and robust price competition.

Competing standards

As noted, however, attempts in the United States to unbundle cable STBs have been resisted. Meanwhile, European regulators are allowing operators to continue the current modus operandi indefinitely; proprietary middleware vendors are simply bundling MHP solutions with their own, forcing content producers to author for multiple standards.

To further complicate the situation, there are not only rival proprietary approaches, there are competing “open standards.” OpenCable specifies two operating environments for interactivity, declarative (OpenCable presentation engine) and procedural (OpenCable application engine). The presentation engine in OpenCable is similar to specifications developed by the Advanced Television Enhancement Forum (ATVEF), which has a DVB equivalent called DVB-HTML. But the DVB version is not HTML, it is a version of XML developed by DVB. It is also worth noting that the ATSC has been working to develop a middleware platform that shares many of the underpinnings of MHP. The DTV Application Software Environment (DASE) represents yet another spin on the issue of broadcast/Internet convergence.

Perhaps the strongest supporters of MHP are European broadcasters and the regulatory bodies that control the broadcast franchises. These groups have been watching as multichannel competitors drive the transition to digital TV, as is the case here in the United States. In June 2001, a group of European broadcasters and consumer electronics trade groups operating together as the Alliance for MHP, sent a letter to European regulators outlining the current situation with the deployment of digital TV services in Europe and their position on the most desirable solution to the current marketplace chaos. Their comments could easily be applied to the current situation in the United States.

The letter explains that the present market situation for digital television in Europe is characterized by vertically integrated digital television platforms using different standards for interactive television services. This means that consumers can only access the interactive content offered by one platform operator at a time. As a result, content suppliers who do not operate their own technical platform must enter into a contract with a platform operator using a proprietary technology in order to have their interactive services carried. And they may need to author multiple versions of this content for different platforms.

The letter goes on to explain that a fully interoperable digital interactive television system across Europe would mean that a consumer could access any available interactive content service via any digital television-receiving equipment. One device, either a set-top box or an integrated television receiver, would suffice to receive any interactive content available, whether for free, via subscription or a pay-per-use basis.

The European proponents expressed concerns that these vertically integrated and technologically fragmented markets will be perpetuated into the distant future, citing statements from cable operators and other industry players that they will opt for proprietary, non-interoperable and closed technologies when they upgrade their networks to accommodate interactive digital television services: “The individual business incentives to opt for proprietary technologies that allow these stakeholders fully to control the access of their competitors to their respective platforms is much more powerful than the willingness to shape these markets in the best interest of consumers.”

Given marketplace realities, this is all an academic exercise. In the United States the cable industry has not been deploying set-top boxes capable of supporting advanced services such as those defined by MHP. For now, the industry seems content to offer digital TV tiers that keep them competitive with the premium content packages and NVOD movies offered by their DBS competitors. Likewise, set-top boxes supporting interactive DBS services have been offered only as a premium option. DirecTV and DISH have taken a somewhat agnostic position about interactive services, allowing multiple competitors to offer set-top boxes and enhanced services via their networks.

This could change if the proposed merger of EchoStar and DirecTV is approved, as there would be a strong incentive for the combined entities to migrate all existing customers to a next-generation platform that would incorporate improved video compression technology, local cache storage and the resources needed to support advanced interactive services.

How does the Multimedia Home Platform enable the desired shift from proprietary vertically integrated platforms to an open horizontal integration approach? Is it even possible to create an open platform with which multiple vendors in competing industries can build set-top boxes and integrated receivers that will interoperate with content from anyone? The experience of the Internet suggests that this is indeed possible; thus it is not surprising that many of the concepts and technologies upon which MHP has been built have their roots in the open systems world of PCs and the Internet.

What is MHP?

Detailed information about the MHP standard can be accessed via the Web links provided with this story. The MHP MarCom group — a trade association promoting the standard — provides a quick overview of the MHP specification and how it works. In a nutshell, this is where MHP fits into digital TV platforms.

MHP is an open, common software platform that provides a standardized basis for free-TV, pay-TV, multimedia programming and interactive services.

MHP will be installed in set-top boxes, IDTVs (Integrated Digital Television) or on multimedia PCs. There it supports media convergence — television with the Internet, for example — and the networking of digital components such as televisions, set-top boxes, PCs, telecommunications equipment or DVD players.

By means of the common API and together with the Java programming language, manufacturer-independent applications can be designed for the MHP system. The common interface provides a standard hardware interface so that MHP-capable systems can be extended by means of modules. (See Figure 1.)

A bridge too far?

The goals of the Multimedia Home Platform are clearly admirable. The list of companies that have signed up in support of this platform is extensive; the consumer electronics industry, long shut out of the markets for cable set-top boxes is prominent.

But MHP may have overreached the window of opportunity, as its most dedicated proponents are struggling to define their digital future, even as they continue to hold onto what is still a very lucrative analog television franchise. Ultimately, the marketplace may migrate to open standards for multimedia. This is inevitable, if one believes that broadcasting and the Internet will converge, and that the Internet will remain open.

The questions that remain unanswered are “How long will this take?” and “What will the marketplace look like when we get there?”

Craig Birkmaier is a technology consultant at Pcube Labs, and hosts and moderates the Open DTV Forum.

Web links

The MHP MarCom Group
The MHP Basics
Digital Video Broadcasting Project - MHP Web site
Cablelabs MHP press announcement
DASE — DTV Application Software Environment