Friday, December 4, 2009

Media Plugins

I've been working on media plugins recently, here are short videos of the results:

That is the VLC media player, playing on a surface inside a Syntensity map. Note that sound works, but I didn't record it for this video.

And this video shows embedded web browser windows that you can interact with. The plugin for that might be useful for other projects, so I spun it off as a separate project, Qtonium. The name is inspired by Awesomium and Berkelium, two projects doing similar things.

As to why a new project and not to use Awesomium or Berkelium: Awesomium is apparently going closed-source, or at least that is the only way I can interpret their taking down the code and mentioning 'new licensing terms coming soon'. Berkelium is open source, but it is unclear if it is functional or useful outside of Sirikata, the project in which it is being developed and used.

And in any case, both are based on the approach of taking Chromium and hacking it to work in an embedded manner. In Qtonium I took a very different approach: No C++ at all, and no hacking of a massive and rapidly-changing codebase. Instead, PyQt is used in a straightforward manner, that is, Qtonium is written in Python. It's dependencies are Qt and PyQt.

The only downsides I can see to the Qtonium approach are:
  • Qt WebKit isn't a complete browser, just a 'widget'. For example, when embedding Chromium as a whole, you get plugins (Flash, etc.), caching, various default behaviors (handling page load errors, etc. etc.). That stuff is obviously useful, so this is a clear downside. But the cost (hacking Chromium) is also very high in my opinion. In any case, over time those things can be implemented in Qtonium if people want.
  • Qtonium doesn't share Chromium's separate process security model. This is true at the moment, but it would actually be very simple to adopt, due to Qtonium being written in Python, and Python 2.6's improved support for handing separate processes. In fact if you look at the code, how to do this becomes quite obvious.

Note that this is part of the approach of having all plugins be Python modules. Those modules can of course load C++ code if they need to (like Qtonium loads Qt through PyQt), so this isn't a limitation, but actually the hope is that a lot of things can be done with pure Python (including ctypes). That way, plugins don't need to be compiled, and it's generally very easy to make them work on multiple platforms. C++ plugin systems tend to be much more complex to work with.

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