"The slow of the international foxtrot is the swing of the whole foot from it's back position to it's forward position"

Actually no. It is formally defined to be from the time that the feet pass to the time that the feet pass.

Count frames in the video. I get something like 1: 19 2: 23 3: 20

If the video is NTSC rate, that's 1 measure of a 29 mpm foxtrot - but are the proportions correct?