How to mask stabilized footage I have tracked and stabilized footage.
I used 2D Stabilization with Autoscale, then turned on Display Stabilization in the Display options. So far, so good.
Then created a mask on undistorted footage (Display Stabilization turned off - only then can see and edit the mask) and parented it to the tracked point used for stabilization (whole mask to single tracker point).

When I use this mask in compositing through the nodes, it is of course undistorted and since Stabilize 2D node info has no outputs, I can't pass Location influence and Autoscale values.
I can make the mask follow my tracker with the Track position node and some math nodes, but the Location influence and Autoscale is still a problem.

Is there any way to simply transform a mask to fit the Stabilize 2D distortion?
The first thing I suggest is turn off autoscale and do the scaling with a Transform node in the compositor, that way you'll have more control on the final output and composition.
You do have access to the Tracker information by adding a Track Position node and manually typing the name of the tracker you want to use. (Keep in mind that that same tracker has to be part of the set of trackers used for the 2D stabilization)
Some manual positioning might be necessary to place the mask on the right place, but after that the mask should follow the stabilized footage.

Here's a possible Node arrangement: