Make a mask come in at specific time on timeline?

[r_tist]

I am trying to cover up something with a mask, but as the subject moves my coverup does not look so good.
Using Alpha Adjust - so the mask is applied to the video clip, but is there a way I can designate specific keyframes for this coverup to come in and out so it does not look so odd?

Thank you.

[r_tist]

More on this... I am applying keyframes in Effects Control to achieve this. If I toggle on the Mask Path to create that keyframe, do I need to mirror this action for the Mask Feather that lies directly below and that's tied to the mask?

e.g. - do you need to animate each attribute separately or does it 'know' that it's a unit that should animate all together as part of Mask (2) parent?

[Richard M Knight]

I would cut the clip and just apply the mask to the cut clip. You could add a crossfire to help the mask come in more cleanly.

[r_tist]

Can you verify is this method is valid or are there better workflows? Going frame by frame and tweaking the mask and manually moving it using Mask Path (is it called tracking, where you make it animate?)...

This is extremely time-consuming and tedious as the subject continuously moves and had a bad hair day. I have had to mask a small area of the hair and ensure no matter how much she moves her head, it's covered up and does not cut / mask out any more than what's needed.

(just can't imagine someone having to do this if it were hours of footage)

Is there a smarter method but how would it work? How would it 'know' where the bad hair piece is?