Thank you for your very detailed response.
I appreciate the time and have read everything twice.
I had previously assumed avi was not supported because my camera’s (trail cams) making those files have never worked through various versions of movie studio. I have been informed both here and by others that only some AVI files are not supported.
I too have always wondered if Movie studio Render times vs Pro were clipped to push the professional version. Maybe that could be my next round of testing. 😉