I have a tip for you regarding rotoscoping in After Effects.

I have a tip for you regarding rotoscoping in After Effects. When I was working on my green screen video, I had a problem where it kept like propagating. It was longer than this, but it kept propagating and kept refreshing the roto brush whenever I make a change on the timeline. There is a solution for this, and it is freezing your frames in the roto brush tool. So to freeze your frames, you double click the layer that you were rotoscoping, and then on the bottom right hand corner you should find this button called freeze. When you press freeze, it will stop the roto brush process and it will basically keep your roto brush in place. So I'm going to press freeze, and a little dialog box will pop up saying freezing. If you can tell by the counter just going in and out of consciousness between me and you, let's pretend like this is actually a good roto brush. So basically what I'm trying to show is after you finish freezing your rotos, at the bottom there should be a purple banner saying Roto Brush and Refine Edge propagation is frozen. Unfreeze to update. Now as you can see, I can click through my timeline without the green propagating banner coming up now and now and now and then telling me, hey, it's updating or it's propagating. One thing you do have to take into mind is that you cannot continue the roto brushing process after doing this. You would have to unfreeze the frames and it will go back to updating the roto brush. Hope this helps.