Creating a background video with menu overlay

Greetings all,

I'm a newbie when it comes to Qt programming and know what I need to do but I'm having a hard time figuring out the necessary Qt pieces that I need to put together to make this all happen.

I'm writing a Qt application that is going to be streaming a video in the background. This is the default state of the application from the moment it starts up. At some point in time the user will want to bring up a menu that will require that the video being shown is dulled (darkened) so that the menu that will appear as an overlay is prominently visible.

The user will do what they need to with the menu and then dismiss the menu causing the video to go back to it's original full brightness/opacity and continue to stream.

I've got a simple program that is subclassing QGLWidget and then is getting QImage's sent to it and displaying it using QPainter in it's paintEvent. I've also looked at QGraphicsView/QGraphicsScene and a couple of other classes, but I'm just not sure which of these (or something entirely different) would fit my needs the best.

The transition from light->dark and dark->light of the video background can either be instant (easier I imagine) or a gradual transition (for more effect if that's simple enough to accomplish).

Any advice or direction is greatly appreciated..

Regards