While I've been in, around the CCTV industry for years what you are describing is what I see some come in and ask about because they saw it on CSI or other TV show.
How to gently explain what they saw on TV is not real software at work?
I wonder if there is any software that does the following:
I have a private video.
I have another video not confidential.
I want a program to compare these videos and generate a file from which I can retrieve the video confidential from non-confidential.