Grinding noise in drivetrain (video/sound now)

[NickD]

I posted this some time back. I have a 2012 N55 6MT that started making a grinding noise in the drivetrain. It started off very quiet and has gotten louder over time. I notice it >35mph and it's more prominent when off the throttle than on but it's there under both circumstances. It also seems to get more quiet when I disengage the clutch. Is this the center support bearing or could it be one of the input output transmission shaft bearings?