How to extract all the frames from a video using MATLAB and do key frame extraction by any standard method?

I have a video to process frame by frame. I want to extract the key frames out of it. So the first task is to grab all the frames. We can read an AVI video using readavi but I am having no idea how to extract the RGB frames. Secondly, if someone can point to any开发者_StackOverflow中文版 MATLAB implementation for key frame extraction (using any standard method) or can post the code here it will be great.

To extract frames use the function frame2im. Here is an example how to do it.

For the key frame extraction I suggest you use some kind of similarity measure (like cross correlation, histogram distance, optical flow, etc..), and look for large changes in neighbouring images.