I have had a similar on a track car where you have a buid up of brake pad dust hardened between disc & pad,,,, It goes when brake applied as you suggest. It sounds exactly like the noise in your vodeo!
This is not a worn out is disc or pad just a slight accumulation of deposit.
To resolve, remove pads and rub glazed coating or any rough spots at edges on a pice of emery paper on a flat surface.
Remove the shine on the disc with fine emery paper by hand, it's not aggresive!
It may not be this, (diagnosis on the internet!!?!) but doesn't cost much to do, just 20 mins and a piece of emery paper.