Mask/Tracker Problem

#1

Hello! I’ve run into a small snaffu with masking. Any help will be GREATLY appreciated.

I imported a tracker from Mocha into fusion, set up my masks on frame 1, hooked up my masks to the FG input of the Tracker and a black BG into the BG input. In the Operations tab of the Tracker, I enabled Matchmove and FG Only. I attached the output of the Tracker into the Masking input of a color corrector and piped my footage into the BG input. I then copied the tracker and piped the CC into the BG input. Then I adjusted the Matchmove to be BG only and changed the name to be Stabilize. These are the only settings I adjusted.

I was using the Stabilize tool to roto in place. The problem I’m running into is that when the Stabilize moves the part of the plate out of frame I’m rotoing and I want the mask to extend outside of the frame on the footage it crops the mask at the edge of the frame.

So is there a way to keep the mask intact when the stabilize tracker moves the mask outside of the frame? Is there another way of doing this so that the mask isn’t cropped?

#2

There are a few things you can try.

  1. Use a crop node to crop the image larger (ie if you are on NTSC, crop out to 1024x768, or large enough to contain the motion of the shot). Stabilize, roto, destabilize then crop back out to the original resolution.

  2. Set the edge mode to wrap, stabilize, use a transform also set to wrap to repo the footage to contain the required element. This may not be 100% feasible if the camera move is too large. Do your roto, add another transform connected to the first and set to invert transform, then destabilize the footage.

#3

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