How to cut a part of a video?

Question

Adobe After Effects

Good afternoon, I need to cut a small fragment from the video and put another one in its place, how can I do this?
here in the background there is a tree on which there is a green poster

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should be like this throughout the video (8 seconds)

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the problem is only in those moments when the horse enters the poster and I need to somehow cut out this poster so that it has what I need on it

Answer 1

If the frame is without movement, then you can simply put your poster on top of the frame, and where the horse blocks the tree, you need to frame-by-frame mask the layer with the poster, repeating the silhouette of the horse. Or the horse in those frames where rotoscoping (roto brush tool) blocks and put on a layer above the poster