the sound in the video sounds to me like it is too FAST to be bottom end noise. also a little too high pitched for bottom end, when the bottom end is coming apart you know, because it sounds like the entire world is coming to an end.
sounds like valve tick to me.
with hydraulic lifters there is a process of "pumping them up" which is basically like working them with your fingers in an oil bath for a while, and alot of guys do not do this.
i think with some driving that will go away