It's kind of hard to explain what im asking. For example, If 2 people are moving (one on each side of the screen), and the camera is still, How do you edit each side of the video differently? Like if you want the left side to be twice as fast for example.
Since the background is still, I know it's not as complicated, I just don't know how to get started.
Another example is editing parts of one person to another person. Like editing the video of ones head onto another, but only the area of the head. You know what I'm getting at?