Use Qualifier on clip underneath?

Hey everyone!
I'm producing a music video right now and I have two clips I would like to combine.

The first clip is a musician in front of a white background.
The second clip is on top of the first one. It is a rain of plastic balls in front of a black background. It is set on "exclusion", so the black background disappears.

Now I want the balls behind the musician, so the moment they "touch" him, they have to be masked out.

I wanted to use the qualifier in the clip with the balls. So that the balls only appear where the white background of the clip underneath is.
But is there a way to use the qualifier on a clip that only shines through, but isn't the actual clip I use the qualifier in? I hope I could describe that properly.

Because of the amount of work and performance issues, I don't want to make a fusion comp out of it.

Sooooooo... Any tips how to do that?

Thanks in beforehand!

Btw: The clip of the balls is a fusion composition i rendered in place. So if you have any suggestions that only work without the black background, I can remove it.

Is it at least clear what I tried to explain? I have the feeling that I failed a bit here

The way I'd do it if Fusion wasn't an option is to create a polygon mask in the colour page and rotoscope it.

Add a white Solid Color to V1, balls on V2 keying out the black, and musician on V3 keying out the white.

Add a white Solid Color to V1, balls on V2 keying out the black, and musician on V3 keying out the white.

There’s a lot of white on that trombone bell, so keying white may be problematic.

Split the difference. Change the background of the Fusion comp to white and leave it on the bottom layer. Then use 2 layers, a luma key for the player, and track a shape mask for the bell of the trombone.

Why is there a drop shadow on the mask? Did I accidentally turn on iMovie mode somewhere?

Good Luck

drop shadow.png (749.45 KiB) Viewed 667 times

There’s a lot of white on that trombone bell

Mmmm...here's where a proper green screen would have helped.

Add a white Solid Color to V1, balls on V2 keying out the black, and musician on V3 keying out the white.

YES, that worked really well! And is easy to reproduce. I have like 50 clips of different musicians I have do do this with.

Thank you all very much! I used the circular mask on the trombone to prevent the mask from keying it out. Next time I will definitely work with green screen...

Cheers!