I've updated my underlying movie clip (actually an image sequence) and now I want to render a stabilized animation using the existing tracks that I've made. But when I click the folder icon on the movie clip and choose new files, the tracks disappear. Is there a way to restore the tracks to the new clip?
You need to load the old JPG (the "proxy" tracked scene)in the Movie Clip Editor, so you have access to the tracking information. Select the trackers toe be used for stablilizing the footage.
In the compositor create a Movie clip node that uses the new image sequence.
Create a "stabilize2D" node and use the tracking information from the old scene on the new scene.