Let's check it out!
I see the Moderators must not have liked my joke about Knacker's knickers since it has been deleted, so I'll move on.
In the video...(bouncy floor)
a considerable gap is shown between the beam support and the post that at one time apparently supported the beam. (One can assume the beam was supported by the post.) It is further assumed that the floor structure moves, deflects, bounces, whatever, hence the need to correct the imperfection. Filling the gap with wedges (kiln dried or not) is the videos answer to repairing the imperfection. This would of course be a temporary fix I suppose.
What one should really be asking is; Why is that gap there? What has happened to cause the gap?
It is safe to assume the post has (over time) either settled or been punched-down by the reoccurring stresses placed on the floor structure.
Obviously the post has no footing below it, or, if a footing is/was there it is no longer a valid support for the post.
THIS, is where the repairs should take place. The post-base should be investigated to determine what (if anything) the post is resting on. If there is no footing below the post then a new footing should be established. Typically a concrete spread-footing would be needed.
The videos suggestion as to how to repair the floor is meaningless and would last only a short time. Cheap it may be, but certainly not the proper and long lasting means of repairing the problem.
Doing what is suggested in the video will only (hang) the post from the beam and not support the post or the beam in the future.
This is yet another questionable idea coming from the Internet and is not at all the way to make this repair.
Reality sucks, don't it?
The "knickers" joke was funnier!