I do not know for sure what the noise is, but I did notice in your short video that you have a coolant leak @ 27 seconds that looks like it is coming from either your radiator cap or the rubber hose that connects the coolant reservoir to the radiator cap. You might want to get that coolant leak fixed so that your car doesn't have the potential to overheat.
Anyway, back to the noise, it's weird how the pitch doesn't change while driving. Since it's really loud by the passenger side valve cover, I feel like it has something to do with a timing-related component such as the camshafts, or cam sprockets. I would take it to a Nissan/Infiniti mechanic ASAP to help you diagnose what the problem is, because whatever it is, does not sound good at all.
Best of luck to you