The video shows:
If a player (with boots to enchant the speed of the soul) steps on blocks of soil or sand (it won't work with sand, you can look at my opkblikovannoy article about Sand and Soil Shower. P2) if there are hatches above them, then the player has a speed effect. But if the player stands on the blocks of soil and the sands above which are half-blocks, then the effect of speed will not appear (Although, as I remember, on java, the speed of the soul appears, even if the distance between the player's feet and the block of souls is half a block).