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QT Jambi: Deployment and Web Start

I’m still having this strange idea to use QT Jambi one day for a Java project of mine Jambi is a pack of Java bindings for the QT framework. Therefore one can use the QT GUI classes from within Java and need not to rely on the Swing, AWT or SWT toolkit. As it maps to native code it is also expected to be faster than Swing or AWT. Like QT it can be used for GPL based open source development fro free.

While the demos look fine I had some doubts regarding the applicability for deployment. Jambi definitely relies on the QT libraries, which - not surprisingly - depend on the target platform. So different pre compiled libraries have to be included for different platforms. For the open source windows edition the whole pack has 26.4 MB (compressed < 6 MB), which is not more but a reasonable addition compared to the size of a standard JRE (compressed < 20 MB). A minimal set for using the GUI (core, gui and mingw) has about 17.3 MB.

So my conclusion: It’s definitely usable. While you cannot create QT applets with Java, web start is possible. However if in a specific scenario - especially web start - size matters then you need think about compression (e.g. with jars).

Related links:

• Jambi reference documentation
• Jambi application deployment documentation

Small Games for Kids - New Release

Besides the two already existing games (GuessWhat and Soundmachine, more information here) I added a new one called SoundVis. The main idea is to animate a kid to make sounds by for instance clapping or yelling. The louder the sound the bigger the blue circle in the center gets. While this sounds trivial it is great fun Note that the microphone has to be functional. A simple test is included in the start screen of SoundVis.

Installation:

Find the new package (including source, licensed under GPL) here. Use 7-zip to unzip them. Launchers (.exe files) for windows are included. Linux users might peek at the included batch files to get a clue how to start the games.

Final Standard for KB Confusion

Is a Kilobyte 1024 Byte? Or maybe 1000 Byte? Xkcd posted the final solution for the KB confusion.

Freemind Icon Set

Long long time ago I can still remember *gg* … I sent an icon related patch to the Freemind developers. My input was appreciated but never found its way into the current branch (development is running in polite ignore mode as with many open source projects ). Today I installed the new 0.9.0 beta 16 and wondered if i will find the polished crystal icons I repacked for Freemind … No, sorry However I patched it again and instead of sending it to the developers everyone can download the patched jar file here.

Install Instructions:

• Download and unzip Freemind 0.9.0 beta 16
• Download and uncompress my patched jar: freemindjar.bz2
• Copy my jar into the lib folder of your installed Freemind (Overwrite: yes)
• You’re done.

H.264 compression test published

Today I found a compression test on different H.264 (and one MPEG-4 ASP) encoders. They tested the compression to visual quality ratio and found out that the MainConcept encoder (German company, recently acquired by DivX) performs best. The difference to the next rank however is marginal and x264 is second. Deciding based on a compression to price ratio will therefore be very easy

Related Links:

• Compression test
• MainConcept
• x264  (on Wikipedia)

Metadata for the MP4 container

Have you ever wondered why there is no title or description in your AVI files just like you expect it to be there in your MP3 files? Well AVI does not really support these things. However the Moving Pictures Expert Group has defined the MP4 container format for audiovisual information (which is very much like the MOV container) and did not forget about metadata: They defined a way to put it in there. However as it always comes with standards, where a whole lot of people talk and try to find common ground, there is not one simple way (like ID3), but several complicated ways to choose from. Therefore applications like VLC or Winamp do not support MP4 metadata out of the box. Due to the string relation to the MOV format however iTunes supports MP4 metadata.

Thanks to Markus Waltl I got some links for tools reading and manipulating MP4 metadata. They all have in common that they are rather slow:

• AtomicParsley - A command line tool for reading and setting metadata in MPEG-4 files. Has also a good explanation of the MP4 atoms here.
• Yamb - A GUI tool using MP4box and AtomicParsley.
• mp4tag - Part of mpeg4ip, a framework for handling mp4 files.

Courses in Summer Semester 2008

Semester started yesterday and therefore also the courses. This semester I’m lecturer and coordinator for 3 courses:

• Multimedia Information Systems - My very own course focusing on Multimedia Retrieval and content based analysis. Takes place 2nd time now, was quite a success the first time: Students and me were satisfied with the agenda of the course and the project results. Find more about it here.
• PR Compiler Construction - A practical course on the basics of compilers to support the compiler construction lecture. There is also a tutorial helping with the implementation tasks of the practical course. Find more information here.
• Computer Games - A first try with my colleague Horst Pichler to create a new course on computer game development bringing together the knowledge of the faculty. While we only had 30 free places in the course and the first lesson will be next week we expect ~ 90 students, which is quite a lot for not mandatory courses in Klagenfurt. Find out more here.