Please help me diagnose this noise from my car when the engine is cold.?

Seeking opinions on this concerning noise.

Background:

2010 Acura TL, 90k miles. Pretty consistently serviced, at least not neglected. I'm the original owner. The car's been great--not a bit of trouble in ten years.

Now the noise as best I can describe it.

It sounds vaguely like something is rubbing on something. Not metal on metal or anything that obvious. It may not be anything rubbing at all, but that's the best way to describe the noise.

The noise is not constant, but it's not exactly intermittent either. It's kind of on again-off again in very short cycles, but it's not regular or rhythmic.

It's coming (I think) from the engine compartment, and with the hood up and the car idling it is very easy to hear, but oddly I cannot tell exactly where the sound comes from. It's everywhere and nowhere.

The sound can be quite bad when I first start the car. After it's been going for awhile the noise lessens and eventually goes away. If the car is warm the noise won't come back after a short stop.

The noise isn't affected by turning the wheel or using the brake. Because I am driving, I don't know for sure whether it is affected by my speed.

Engine oil is full and clean.

Nothing obviously broken or leaking.

Car drives normally.

Here's a video. It's not superb, but maybe good enough. Clearest examples are around :50, 1:07, and :28.

I made the video a week or two ago. The sound is a little worse now. 

Weather is cold but not freezing.

youtu.be/UPnakPqKnSA

Thanks!