How do I render video with rotoscope mask? When rendering my video, the background image with rotoscope doesn't show. What am I doing wrong?
What I'm trying to achieve:

How it renders (imagine no mask lines):

and I notice that also, the mask lines keep shifting. Is there a way of locking them in place?
The Viewer and  Composite nodes are different outputs, The Composite node is the one that is rendered out and saved to a file. The viewer is just to preview the result. Connect the composite so that it follows the same node path as the viewer, otherwise the images get processed following different transformations.