Mask in a moving scene
I want to do a kind of basic thing that I thought wouldn´t be so hard; but I am stuck now. :(
Here´s the idea: I film a person in front of a mirror (seeing the person looking into the mirror), then walking in a half-circle to see at the end the person from side-behind and the reflection of the face in the mirror. As you can imagine, I want the mirror to reflect something else than the persons face. So I filmed the same scene again, but this time you can see something different in the mirror. I filmed it twice just using my body/hand, meaning that the position and time of the camera is NOT the same.
Question: how do I get to line up the second videos mirror to the first ones?
In post-production, I thought of masking out both mirrors, using Mocha (I have Hitfilm Pro). Then, I thought of tracking the four points of the mirror (original video), using the Quad Warp Effect for the second video mask and pin the 4-points of the Quad Warp Effect to the 4 corners of the first video. But by using the Quad Warp Effect, it (obviously) not taking the 4 corners of the mirror but the 4 corners of the whole masked video.
Anyone has a better idea how to get it done? I could do it manually, but it wouldn´t be that smoothly.
I hope you understand my problems. If not, I could attach a short video for better understanding.
Thanks in advance!