archimedes said:

Great tool! I'm currently using it to color transfer Fellowship of the Ring EE. It does a good job. However, I've run into following problem and have no idea what causes it:

Input

Reference

Result

I'm using a single color space model and have tried the stabilization parameters 0, 1, 500 and 1000. I get similar results for all of them.

In some cases the result can be very sensitive to the cropping, and it may help to select part of the frame to construct a model. This is what I get if I select the left part of the frame in the reference, and then the exact same part in the test frame:

Reference:

Test:

Test matched to reference: