What is the reason for these strange radio altimeter calls?
"Four hundred" was likely annunciated twice due to a bit of a dip in the terrain that would cause it to pass the 400ft level twice. The "hundred above" call-out is for 100 feet above decision height to let the crew know they will need to make their decision soon to either continue or go around. After that, you hear the "two hundred" and "minimum" call-outs right after one another. The "one hundred" call-out afterwards signifies 100 feet above ground level.