Nice video, did you notice the robber bees.
They were the ones landing on the edges of the landing board, wondering around, then suddenly making a mad dash for the hive entrance. In just the 1st couple of minutes I saw 3 robber bees get into the hive and 1 intercepted with a little skurmish an inch or so in front of the entrance. That is a very good video on studing how robber bees work. They are landing on the sides of the bottom board or even the outside edge of it then zigzagging across the front before making their mad dash. The speed of the robber bees in relation to the hives worker bees are at about a ratio of 3:1.
I would either reduce the entrance by half or put on a robber screen. If that was a warm day the hive is too weak to police the entire entrance.
Also notice how the departing worker bees are climbing up the front of the hive before taking flight while the returning bees are making controlled crash (Aircraft Carrier style) landings, plopping down as best they can. That is a typical coordination of work for greater efficiency.