I don't have first hand info, but that youtube video seems like a rather crude comparison to me - why go through all this trouble and then use a different lens for the different shots, which will add another uncontrolled factor?
this comparison seems more useful to me:
I can't help but arrive at these two film stocks appearing so close in results that I might as well think of them as interchangeable.
www.35mmc.com
the odd thing is that visually they look very similar, the data sheets are quite different, but people in the comments report that the DX code on the fuji 400 is the same as on the kodak 400.