[PyQt] PyQT4 w/ Phonon Performance Problems

[Phil Thompson]

On Mon, 16 Mar 2009 09:13:30 -0700, comsatcat <comsatcat at gmail.com> wrote:
> Hello,
> 
> I've been playing with the idea of developing a multi video display
system
> using phonon and pyqt.  I've written some prototype code using a
> QGraphicsView along with QGLWidget for the viewport.  I'm getting pretty
> poor performance (1fps on average) when displaying more then 2 or 3
videos
> on Linux (yes my direct rendering is conigured correctly) and on Windows.
> Ideally I'd like to be able to display up to 13 videos at a time, one
being
> in a larger QGraphicsView (with audio) while the others are displayed in
> thumbnai llike configurations.
> 
> I've pastebin my code at http://pastebin.ca/1362335
> 
> In a nutshell I'm looking for tips for managing performance when
displaying
> large video files from multiple sources (QUrl based, generally http://
> urls)
> a long with local video feeds (from local files) and from streaming input
> sources (such as webcams and tv tuners).
> 
> Right now when I load a large video file from a local file system
(700+MB)
> it acts as if its loading the entire file or a large junk of it in
> memory...
> I don't get a large aount of memory usage in my app, however when I
monitor
> the CPU usage it spikes to 100% utilization for the python process
running
> the code (this also happens when displaying multiple smaller videos
(50MB).
> Am I not doing something I should be or is pyqt4 + phonon just not up to
> par
> when dealing with multiple video sources at a single time?
> 
> Just some background on the system I'm using as it may be applicable..
its
> a
> 1.6GHz Intel Atom processor, 1GB ram, Intel video card (3d configured
> correctly).  Python 2.6 w/ PyQT 4.4.4.2 on Ubuntu Intrepid (8.10, native
> package not build from source) in Linux, and Python 2.6 w/ PyQT 4.4 on
> Windows XP Home Edition.
> 
> Any feedback would be greatly appreciated.

Any performance issues are unlikely to be Python related - you might be
better asking on a Qt mailing list.

That said, I would see what performance you get without using QGraphicsView
etc.

Phil