cannot view the video at work says its been deleted or re-named?
but, based on your description, id say check the down pipe, i had a knoking that i could not work out where it was from, was somewhere towards centre/pass side of the car near the bulk head, but noone could work out what it was including a garage, anyway, after about 3 weeks i took it back to the garage and asked to borrow a ramp, checked down pipe and it was slightly loose.
could be the same problem, my mate had a clunking noise that he couldnt work out what it was shortly after and turned out to be the same thing...