Question about framegrabbing/video effect chains ..

Martin Sandsmark sandsmark at
Wed Mar 3 14:58:22 GMT 2010

On Wednesday 3. March 2010 12.48.52 Zachris Trolin wrote:
> I'm new to QT and would like some pointers of how and what can be done in
> the way of video manipulation.
> I'm very interested in how to grab frames, or perform manipulation on
> framedata using QT and preferable phonon (although any other suggestion is
> welcome).
> I would like to give it a try to implement a VJ:ing application, I have
> used pd, keyworx, grid etc, and they all have some problems.
> The very first step would be to implement a variable rate videoplayer, but
> soon after comes frame manipulation: preferably done in QT  (something
> like the composition demo, but with videostreams. ).
> Any suggestions?

There is some API in Phonon for video frame manipulation, but it isn't stable 
nor supported in all backends yet.

You can see a demonstration of it here:

The code for Quasar is here (although unmaintained and probably not working):

Martin T. Sandsmark

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