Write once, run anywhere: a lesson for digital TV
If, as reported, entertainment giant Paramount throws its weight behind the Blu-ray high-definition DVD format it would seem like a vote in favor of using Java (Sun PDF here) in digital TV entertainment.
While for some this might not seem and obvious association and might be considered a completely new departure for Java by many more, digital TV is actually very close to the origins of Java.
With the Consumer Electronics Show in Las Vegas, Nevada, I plan to look at the underpinnings of digital TV, its relationship to Java, the problems that DTV has and how - by looking to the enterprise world - Java may help over come them.
Looking back, to the origins of Java, you will find that having built a hand-held device - *7 or Star Seven - the Java development team (or rather at that time, the Oak development team) looked around for other applications for their new baby.
One of the main suggestions was to use it in TV set-top boxes (STBs). However, back in the early 90s the TV industry (both satellite and cable) was too young and embryonic to see a need for Java on the STB, so this idea died an early death. Java of course didn't, and went onto to become the success that it is now.
The idea didn't completely go away, though, while TV standards themselves have come a long way since those early days. Within the world of digital TV the Digital Video Broadcasting project (DVB) is one of the key players. This is a consortium of more than 270 organizations in 35 plus countries that have defined a host of standards. These standards include:
MHEG-5: is part of a set of international standards relating to multimedia presentations. In the UK and New Zealand it is the digital TV standard and is used with Freeview. MHEG-5 is a declarative language focussing on the presentation of text, image and video content.
MHEG-6: This was an aborted attempt to extend MHEG-5 to include Java. In this model Java applications could manipulate MHEG-5.
MHP: The Multimedia Home Platform (or MHP) is an open standard originally created by the DVB project for digital broadcasting. MHP is oriented around Java and applications are either written in Java (and called Xlets) or HTML. However, although it is being adopted in many Europe countries, MHP has not been adopted in the UK.
From the Java Community Process (JCP), meanwhile, we have Java TV API 1.1 or JSR 927. Java TV API 1.1 is a Java specification specifically oriented around digital TV. The core element of the Java TV API is an Xlet - that you may note was mentioned in the section on MHP. Indeed, all of the Java TV APIs are included in MHP. So what's the difference? Well MHP is based on the DVB project's other standards and as such is rather more tied to the underlying technologies. In contrast Java TV does not make such assumptions and describes the necessary lower-level services in terms of generic interfaces - as you might expect. Thus, Java TV can run on a wider variety of platforms.
The big weakness of J2ME on mobiles, is that each handset vendor creates their own implemention of the platform - trying as best they can to stick to the spec. Even ignoring the various extensions, the reality is that each implementation is slightly different, partly down to vagueness in the spec. and partly down to bugs in the implementation. This means that, in practice, you cannot assume that a J2ME app that runs on one handset will run on another - (even if they are from the same manufacturer!) This places a huge burden on developers to try and test on every handset on the market (oh and of course even the SAME handset can have different firmware for different networks).
If Java is to succeed in the Digital TV field then there needs to be a single implementation of the core VM and libraries - leaving just device drivers to the set-top vendors. The obvious approach (and therefore the one least-likely to be taken!) would be to create an open source, or at least a community-based project to create such a platform. Sadly something tells me this is unlikely.
Why java wasnt used originally
The reason java wasnt used is because it needs a lot more processing power and memory than c. The boxes are much more expensive to make (or were when digital stb's originally came out) and Sun didnt want to make a cut down version of java. I remember seeing some early attempts at java powered boxes and they were painfully slow.
Surely this is old news?
6 or 7 years ago I was chatting to the guys who developed the transmit side of satellite/cable TV at Canal+.
They described the market then as "Java for the set-top box, Ada for the transmission". The reason? If a STB crashes, 1 person can reset it locally and not too much damage done. If the transmission system crashes, there's a hell of a lot of advertising revenue that can be lost!!