I have a square adjustment layer which I have to animate to follow a screen around during a video. I want to apply some Color Correction filters to only that square, and a separate set of photo filters to the rest of the video. This way the filters do not overlap.
I tried to make the negative of that layer by duplicating and using "Invert Selection" but that didn't seem to invert the selection. I also do not know how to link the animation on the two layers (position, size, rotation, etc.)
The easiest way is to use Track Mattes. This will let you use one layer to automatically 'mask' another layer without the need for manual masking.
Take your square adjustment layer and make any effect changes you want, then create a new adjustment layer (make sure its comp size to fit fully over the video). Place this new layer (background adjustment layer) below your screen adjustment layer.
Select the background adjustment layer and set the Track Matte to Alpha Inverted. This action will turn automatically turn off the visibility of the top layer which is normally the desired effect, but in this case we want to turn it back on. You should end up with a layer panel looking something like this:
What this has done is the background adjustment layer is using the screen adjustment layer as a window. So wherever the screen layer is, the background layer wont be visible.
For what you are trying to do, I think you need masks rather than adjustment layers. An adjustment layer simply applies an effect to all layers under it. If you mask the adjustment layer, then it will impact all layers under the mask in the composition. You want two masks that are the inverse of each other so that you can apply different effects to each masked area.
Update: As I was thinking about this a bit more, I realized there is a simpler way. You don't need two masks, you only need one. Apply one effect to the entire background layer. Then apply a mask to the foreground layer that needs to be tracked. You can apply whatever effect you need to that layer and it will only contain the portion of the screen that has your different effect and will be layered over top of the base plate.
