Before and after video comparison queation.

[NAS05]

• Hi guys, Im trying to do a before and after comparison and im trying to use a mask to remove the mic as it crosses over it to show a content aware thing I did. Kind of like a slider. Im not sure if im setting the track matts right. I've toggled them all different ways and I'm still not getting what I need. (Ive reset the track Matt's back to default) If someone know how to over come this. I would greatly appreciate it.

[dj.summitt]

Hey man! Really hard to say since you don't have any keyframes or layer names. But I'll try to walk you through this. 
This is if you are wanting to show before/after/before:
You put down the un-retouched later. Call that BG. 
Now bring in your retouched layer. Call that FG. 
Put FG above BG on the timeline. 
Now create or bring in the layer you want to use as a Track Matte. Call that Layer TM. 
Key frame it moving as you wish. 
Now put TM above FC on the timeline. Set the TrkMat on FG to Alpha. This should hide the TM layer. 

https://helpx.adobe.com/after-effects/using/alpha-channels-masks-mattes.html#track_mattes_and_travel...

Done. 

[Ko.Maruyama · Accepted solution]

It may be that your Shape Layer doesn't have a Fill or Stroke so there's nothing to matte with.

You probably don't need a track matte at all.

#1 Original - Apply Effect Linear Transition Wipe  (You can animate the percentage of transition)

#2 WOM (I'm guessing that's without mic)

There's an angle, but it makes for an easy "Before and After" if you want to show top/bottom, left/right, or diagonal difference.

more on Transition Effects at Adobe's helpx:  https://helpx.adobe.com/after-effects/using/transition-effects.html#linear_wipe_effect

[NAS05]

Thanks for that! It worked just like I wanted it to. I appreciate you reaching out and helping me.