screensaver while playing quicktime

Hi everyone, here's another stupid noob question.
I haven't noticed it before since I used to use VLC but when I watch a movie in Quicktime, the screensaver isn't disable wich means that after a given time, the screen would dim out and then the screensaver turns itself on. I lookup through all the properties for Quicktime and didn't find a way to disable the screensaver while playback.

Can anybody help me please?

You probably know that if you place the mouse in one of the corners of the screen you can start the screensaver. What you might not know is that if you place the mouse in another corner it will disable the screensaver. You can assign which corner does what in system preferences.

thanks for the reply.
actually I did setup a hot corner to disable the screensaver and it works. however my display is supposed to shut diwn after 15 min of inactivity and it does shutdown even when using quicktime but not while using VLC.