My other car - what would this startup sound be?

I recently added a commuter to my vehicles. I have some work to do on my 98 Gen 1 Taco so this will be the parts runner.

It's a 2008 Mazda3 S Hatchback. 5 speed 2.3 engine. 96K on the odo. I made a video of the noise. It doesn't sound like a belt slipping. I wonder if it's my AC clutch but the AC isn't on but it could be int he pully. I guess it could be alternator bearing as well. Car runs great otherwise. Only does this on cold startup.

https://youtu.be/7DLPjR_9Rrk

 

I can only guess that either belt is slipping, or bad pulley, or a combination of the two. I'd probably start with cheaper stuff by putting a new belt, idler, and/or tensioner pulley and see if that fixes it. All of that is probably going to need replacing soon anyway given the mileage.

Hopefully someone else has some more insight than my obvious suppositions..

 

That's my guess. I am going to get my wife to start it up while I get close to it and see if I can't pin-point it. Never had a Mazda before. Japanese mostly like my Toyota but who knows where all the parts came from. Cool little hatch though!