Maybe not useful for this thread purpose, but so as to include it for anyone finding this thread in future,
here AvisynthTracking (actually given the name of 'AvisynthTrackin' in zip, minus the final 'g'):-
https://forum.doom9.org/showthread.php?t=154010
Requires some version of Python (not the Vapoursynth one, so I think maybe v2.0).
(As I recall, I had v3.0 Python installed, and had to figure out that 'print' had been changed from statement to function 'print()' [for v3.0], or vice-versa,
so I just used v3.0 myself [after editing]).
I tried it once for a short time, tracking C3PO coming over some sand dunes, tracked him from some distance (quite small) up
to reasonably close, so is able to track with changes in size.
Dont know if anything could be done to eg create masks and deshake non tracked object, then re-layer the tracked object,
compensating for the deshaking.