Knocking noise coming from somewhere

What is your question?

I have a video that shows the faint knocking noise that I can hear when driving. It appears to happen regardless of whether the car is accelerating, braking, or coastindg in neutral. It sounds like sometimhing is flapping in the wind and I have no idea what it is.

What makes this problem better or worse?

Driving between 20-40mph

How long has your 2012 Buick Enclave had this problem?

Several months