How can I quickly create movies?

I have a large code which generates several 120x120 matrices which I want to systematically record and make a movie out of. Because there are so many simultaneous matrices and I want to run several matlab sessions at once, I just save the data and make the movies later. However, it literally takes hours to use imagesc and getframe to create the movies. Each result has about 3600 frames and I have about 6 or more movies I want to make. Since it takes about 2 seconds to generate all 6 pictures (using imagesc), were talking about 2 hours or so, just to make a movie for one model. This is almost as long as it takes to actually run the model, so its very frustrating for me.

Are there any other ways, perhaps using external software or otherwise, to quickly create movies?

[Geoff Hayes]

Christopher - it isn't clear why you don't create the movie as you go. Is it because you have one MATLAB session for each movie you are making, or each session produces an image that is combined into a single movie (so the movie combines images from different sessions)?