How to get the time that a picture in video change?

I have a video showing a power point slide. I want to get the time of video that the slide change to next page. I 开发者_C百科use Windows media encoder to make video. Can it be used?

You can use a frame similarity measure.
The simplest would be the SSD - Sum of Square Differences. For each 2 consecutive frame calculate the pixel-pixel difference, square it and sum over all the pixels. If for a particular consecutive frame pair the result suddenly jumps over some threshold, it means that the frames are different, and there was probably a slide change.
The compression of the video will affect the threshold value (more compression = more compression artifacts = larger differences between the frames => higher threshold for acceptable difference).