How to animate focus/blur intensity on a VSE strip I am trying to animate the focus/blur intensity on a video strip, and have come across  this video. 

It looks interesting, but it's just too fast for me to follow. 

I like the fact that it appears to have some parts of the frame in focus and other parts out of focus, and wondered if anyone can spot and explain how this is done.

I assume this script's main purpose is to enable one use the compositor on video strips, right?
Sorry the blur implemented in the vse doesn't use an image value for scale (blur quantity is determined by image value), so all you can do is mask the blur strip with a shape (like a texture). Then Alpha it over a copy of the source strip.