HELP - What is this noise?!

[Naraino]

Urgent!, PLEASE HELP!

I've just been out driving for an hour then just as I arrived home this loud metallic ringing noise occurred. Please watch the video, what the hell is it? There is nothing hanging down on the floor...

 

Car is a 2017 A3 saloon 1.4TFSI COD. 

[enc]

A couple of things to bear in mind …if there’s no exhaust parts hanging down /loose, Maybe a stone trapped between brake disc and backing plate ! It happened to me once! Maybe a damaged backing plate making contact with a brake disc? 
I noticed a squealing sound at one point … maybe a sticking brake calliper? Are any of your brake disc getting exceptionally hot?