Copying mask without Scaling

[Fartnoise9]

Hello! I have autotraced a mask to a solid and am currently trying to paste this mask onto an mp4. The issue is the solid was scaled and when I copy the mask it tries to extent itself onto the mp4 instead of what I am trying to do which is to copy it to the same current position dispite the two layers having different things. Is there a way to pre compose just a mask? I can't pre compose the solid because when I autotrace that it traces the composition instead of its contents.

[Mike_Abbott · Accepted solution]

How about duplicating your masked solid and using it as an alpha track matte for your mp4 ?

[Fartnoise9]

Thank you so much!