Changing Virtual Background 'Enlargement,' i.e., size-relation to you onscreen

It's easy to find great 'nature' virtual backgrounds (bg's)  and upload them to make you look like you are sitting in front of a beautiful lake, river, waterfall or green backyard. Lately I have also uploaded several 'motion' video backgrounds, so the river/waterfall and tree branches appear 'live,' moving, like I'm really outdoors (but with the full lighting & noise control of my studio/office.)

However, some of these 'motion video' bgs are at too close a perspective (see attachment,) so for example, if I call up a repeating video of rain falling on a lotus pond, the leaves and raindrops are huge, making me look like I must be halfway submerged in the pond 🙂 instead of it being 25 ft. behind me.

Using a screencast adjustment program like iGlasses, I can enlarge my face to take up more of the screen. But is there a way I can pull back the size of the background, so it looks smaller, more distant, without going into a video editing program and changing the resolution?