AnimeMusicVideos.org

I've always wondered how he changes the color in his video. More specifically, his colors always appear to be bright, then dark, the bright again. I'm not sure how to explain it. Here's a video to give you an example of his effect (0:00 - 0:09): http://www.youtube.com/watch?v=Qg0S9GfRrzc&feature=cha...