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Television Media

DigitalTV MHP Development Tutorials 13

Posted by Hemos from the get-your-TV-on dept.
Cpt Kirk writes "For anyone wanting to get into digital interactive tv development using MHP, we've got a couple of tutorials online for you, check em out and let us know if they're helpful. Esgem MHP Resources"
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DigitalTV MHP Development Tutorials More

DigitalTV MHP Development Tutorials

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  • Well, TV content is cool. For any educational programming on TV, it is priceless. For WWF, it is funny, and lame. Developing online content has always been a problem for some of the companies that I am familiar with, because TV audiences are ADD or ADHD almost always. Also, no one wants to miss the actual show. TV content should be combined with TiVO or something similar.As for content tutorials, human psychology comes into play as much as everything else.
  • I don't know about anyone else, but I find this incredibly exciting. Interactive TV is just around the corner, and it's going to change everything.

    Imagine watching a conference, and being able to ask a question from around the world. When real-time electronic translation becomes a reality, you don't even have to speak the same language as the person you're talking to!

    Imagine watching sports, and choosing the angle of view!

    The possibilities are literally endless. Let's jump on this, and Linux will be the OS that leads interactive TV into the new age of entertainment.

    • Let's jump on this, and Linux will be the OS that leads interactive TV into the new age of entertainment.

      Linux on an STB would be really great, but I don't think you'll see free software implementations very soon. For a start you need drivers for the MPEG stream decoders and assorted content protection systems (read, patented copyright-protection algorithms).

      Then you need a decent Java VM plus an AWT implementation that doesn't use Motif & X-Windows as the display renderer (although companies like Insignia have gone a long way to providing that by porting the AWT to use QT-Embedded). Also, the AWT implementation really needs to be targetted to use remote control hardware, rather than assuming there's a keyboard somewhere in the system.

      Then you probably need the low level protocol stacks to handle stuff like DSM-CC (the ISO protocol used to transport application data over an MPEG transport stream). Again, there are content control issues there.

      There will be Linux based STBs from the big AV guys, but if you expect the source code to be available to all these layers you might be in for a nasty shock.

      Jon.

      • Can anyone say Nokia Media Terminal ? :-)

        Thats about as open source as I think it will get for now.

        In my experience, a lot of the STBs these days are being based on linux, its just that they aren't open platforms :-)

        Cpt Kirk
  • Does anyone know what this story's about? I mean, seriously.

    MHP something? From whatsisname? Something about digital TV?

    Sigh.

    • MHP (Multimedia Home Platform) is essentially a system for encoding and displaying HTML pages extracted from a DVB/MPEG stream.

    • Re:What? (Score:2, Informative)

      by JKR ( 198165 )
      Basically, MHP (Multimedia Home Platform) is about authoring and delivering applications to your set top box (or MHP-enabled TV) along with the MPEG video and audio streams. Java is the standard language used, as now mandated by the MHP specification, and HAVi provides the specification for the Java-based user interface classes - things like HListGroup, HTextButton etc.). I co-ordinated part of the HAVi specification for a period (the Java user interface code) up to the release of the HAVi [havi.org]1.1 specification.

      For example, the tired old stock-ticker applet running in real time alongside your news channel, or the navigator application that tells you what's on now and next (although this would probably be resident on the device.) are MHP apps.

      HAVi is more than that, though. HAVi is a firewire-based peer-to-peer network for home A/V equipment, enabling a "dumb" device like a CD-player to ask a "smart" device like a TV to display it's UI for it, on any TV in the house. I'm using "dumb" and "smart" here to refer to whether the HAVi device has a Java VM & display capability.

      It's interesting that the site chose HListGroup - it's the UI widget that caused more pain and suffering than all the others put together, because it's so much more complex than simple stuff like a button.

      Sadly, I'm not working on HAVi any longer. I'm sure someone here has current knowledge, though.

      Jon.

      • Thanks for clearing that up, Jon. Someone should have moderated you up.
      • That would be why I chose HListGroup :-)

        I'd seen so many comments on mhp forum sites asking "how the hell do I make it look like I want?".

        So I thought someone should do a proper explanation. I've done the basics one to now, which explains Xlet, XletContext and the basic lifecycle.

        Next stop getting input from remote controls (or the Event handler) that should be a laugh... four bloody ways to get the same information... nice.

        Cpt Kirk
        • Next stop getting input from remote controls (or the Event handler) that should be a laugh... four bloody ways to get the same information... nice.

          How do you mean? I agree the event system is overcomplicated (or at least, it was when we re-drafted it in San Diego last year - I assume it made it into the released spec.). Mostly this is the fault of Java - the AWT 1.1 event model does not map cleanly so we set up a whole new set of events for HAVi.

          It boils down to how good your AWT port is - remember, there's nothing stopping you creating a custom AWT that can generate and dispatch HAVi events at the native level - just hack on the AWT native canvas code if you're basing your port on the UNIX PJEE3 source. That and a native HAVi window class should solve a whole lot of problems that trying to layer HAVi/MHP on top of plain jane AWT can cause.

          From HAVi's point of view, everything is lightweight so doing this can also clean up a lot of useless peer-related code in the bowels of the AWT, including that god-awful lightweight event re-targetting mechanism.

          • I was more on about the focused app awt queue, unfocused subscribed awt events, unfocused exclusive subscribed, and unfocused shared subscribed events.... lots of fun, especially trying to explain it in a tutorial :-)

            Probably have 4 complete examples showing them...

  • Clarification (Clarified MHP ?) (Score:1, Informative)

    by Anonymous Coward

    Ok, sorry I hadn't created an account :-)

    If you want to e-mail me about this tutorial kirk.bateman@esgem.com [mailto]

    The tutorial is for developers using the MHP (Multimedia Home Platform) for Interactive TV content, which is all based around the javatv xlets and some other related technologies.

    Basically, I've been working on some tutorials, since most mhp developers seem to have some problems with the slightly weird way it works. Anyway, Tutorial #1 is about modifying the way an HListGroup is drawn and Tutorial #2 (which probably should have been done first :-) is about the basics, a simple Xlet and explaining the Xlet class and XletContext class, a sort of get you started thing.

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