Can i use MeeGo (www.meego.com) to make my own handheld equipment? To distribute mobile or notebook or desktop as embedded equipment, with my custom application on it for multimedia?
Can i use MeeGo with Java/D or C language? Multimedia and cross platform is never easy. Is MeeGo the right choice?
Lots of questions, I'll answer them one at a time.
If your custom hardware runs an ARM or Intel Atom CPU you absolutely can use MeeGo as the OS. The downloads page has images for both platforms, as well as images for netbooks. The only caveat is that most of the source is GPL. If you patch the MeeGo distribution in any way, you might have to release the source code for it (depending on what it is you changed). Custom applications aren't bound by the GPL however so your app can be closed source if you want.
MeeGo is based on gcc-4.5.0. Which means you can use C and C++, and perhaps some Java via gcj. The MeeGo APIs are centered around C and C++ though. If Java is more your thing, the Android Open Source project might be a better choice, but since it's more specialized than MeeGo it might be more difficult.
MeeGo comes with GStreamer 0.10.30 which is the standard C-based Multimedia-framework for Linux. It's a very powerful framework based on streams and sinks. In other words, it's very modular, and in theory, you can easily replace or plug-in to any part of the rendering pipeline.
