Yes sorry, failing drive-belts can have a loose flap or strip of material on the outside which flicks around, making regular noises like yours. Just a guess though, and as Dad says, the noise wouldn't go away just because the engine is warm. Or would it? If it is the cam belt failing, usually big problems if it breaks. A short length of garden hose or similar, one end on the black plastic cam-belt cover and the other end to your ear might give a clue (don't stick a screwdriver in your ear, not the sharp end anyway). Better safe than sorry with cam belts. Your auxiliary belt looks ok in the vids.
Harping on about belts a bit, but the timing and sound of that noise ........
(The cam-belt idler pulley on my old Lag started to seize up and the belt howled like a banshee at idle, and went quiet when the engine warmed up! But that's a different story altogether).