What's DVB-MHP, and Does It Matter?
By Leslie Ellis -- Multichannel News, 11/18/2001 7:00:00 PM
Last week's batch of technology clippings included an item from Cable Television Laboratories Inc., which said OpenCable will adopt a set of European interactive-TV specifications known in the lingo as DVB-MHP. That's short for Digital Video Broadcast — Multimedia Home Platform.
On the surface, the development parallels a widely held belief that European cable and satellite-TV providers are further along with interactive TV than are U.S. video providers. Translation: Join 'em.
Then there's the stuff not directly stated in the release. It turns out that Sun Microsystems Inc.'s Java set-top software is a binding element in the technological goo that makes up the 1,153-page DVB-MHP specification. A key component of that software suite is the Java Virtual Machine, or JVM — an acronym that's already cropped up with increasing regularity among set-top software providers.
Several translations are suddenly in order, starting with DVB. Based in Geneva, DVB is a consortium of some 300 companies from 35 countries. Its mission: to forge interoperability among digital TV services, regardless of distribution method (satellite, cable or terrestrial).
MHP is a subset of the larger DVB. Its mission: To write the framework for advanced interactive-TV applications on digital, MPEG-2-based (Moving Picture Expert Group) video networks. Again, MHP doesn't care who carries the interactive stuff, be it cable, terrestrial or satellite. It just defines how to do it.
The notion of a virtual machine, though, is a tougher translation. We'll start at the beginning: Usually, when you buy any sort of machine, it does what you bought it to do and only that. A chipper/shredder chips and shreds. A blender blends. A dryer dries.
But along with automation and software, a new-ish type of machine — the "virtual" machine — entered the foreground. It is "newish" in that it is new to cable. But at its technical core, the notion of the virtual machine isn't all that new. It's decades old.
Virtual machines allow a grouping of chips, governed by software, to do things other than what they were originally intended to do. Where a typewriter does one thing — makes words on paper — a word processor makes words or pictures, on paper or on a screen.
In a sense, then, all PC software is a sort of virtual machine. As it gets updated, it allows the machinery of the application do new and different things.
If you've heard of a virtual machine before, you've probably heard it with a specific prefix: Java. Java technologies were invented by Sun Microsystems. There is the Java "platform," which is all of it. Then there's the Java programming language, which is widely taught by computer-science colleges around the world.
Translation: Piles of computer programmers know how to write in Java.
Then, there is the Java virtual machine, or JVM, which is a combination of an interpreter — the part that reads the code — and the Java language, or the code itself. Think of it as middleware's engine — but be sure to check with your potential middleware providers to see if JVM is indeed their engine.
Up until now, the middleware camp was largely divided. Some pursued JVM, and did the legwork to get their Java licenses in order. Others pursued the Internet's HTML, or HyperText Markup Language. Still others went with their own, home-grown (read: proprietary) approach.
As it turns out, JVM is already fairly pervasive. If you use a newer Palm Pilot, or a high-end cell phone with a menu of options, you're probably already using a JVM.
On a set-top level, technologies like JVM matter because they theoretically provide a cushion of control when dealing with interactive-applications providers.
Say, for example, you're tied to a guide provider that nestles its code inside your set-tops. You're thinking that provider has too much say over how you proceed with set-top resource management — how much processing power and memory gets used by which interactive applications.
With JVM as the "engine" within DVB-MHP, and by extension, OpenCable — and with a large and growing base of software coders who write in the Java language — suddenly there's a path toward moving the guide, or any other application, on top of the JVM.
Translation: Control.
Plus, all Java-based technologies are community-governed, meaning they are at least more "open" than other, more proprietary options.
Still, for the U.S. to quicken its pace in ITV — which necessarily means attracting the content that will get things going — it probably makes sense to consider what DVB did, and attract all distribution platforms to one method.
Sure, that's a tough competitive pill to swallow. But it's probably necessary to reach the original goal of set-top middleware: a "write once, run everywhere" environment for the content community. OpenCable and DVB-MHP is a logical start.
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