Okay kiddo, so video matting is like cutting out a picture from a magazine. You know how you use scissors to cut out the picture and leave the background behind? In video matting, you do the same thing, but instead of using scissors, you use special computer programs.
Let's say you have a video of a person standing in front of a green screen. A green screen is just a big green background that you use when you want to add different backgrounds to your video later on. But when you want to make it look like the person in the video is really standing in the new background, you need to cut out the person from the green screen.
That's where video matting comes in. The computer program can look at the video and figure out which parts are the person and which parts are the green screen. Then it can remove the green screen and leave just the person in the video. It's like magic!
This comes in handy for all kinds of things. You might want to add a new background to a video, or create special effects for a movie. With video matting, you can do all that and more!