So the plan is to make a video that has one person in midle or at a specific position in the video moving in real time and things or people that surround that person to move x times faster without covering or ruining the video by stepping in over the main character. I've seen a few videos with this, in my mind I think it's been done by placing from the beggining of the video the main character in some place that nobody steps in so that it can be done with multiple layers and mocha. Is it like that? I would really appreciate some help about this.
The subject is green-screened and the background shot independently.
and if you want some people to cross in "front" of your main character so it looks more real...green screen THOSE people....so that you use your first composite as your new background, and add the foreground people...
light everything and people the same ( same key direction etc )