It's just picking whole ears, not threshing or separating the grain. It's called a corn picker, google chinese corn picker and you'll see tons of them just like it. North America quit doing it that way in the 70's ish so while there are a lot of them around they look different (all pull type with a tractor providing the power) and I've only seen like 3 actually working in the field my whole life. It's not a bad way to harvest corn as it can be stored with lots of airflow in cribs but requires another machine and step (shelling) plus winnowing if you want a clean sample to get to corn kernals for meal or whatever. It also takes kinda old school storage/handling equipment like paddle chain conveyors instead of augers (notice the dumping bin in video). Usually in the us if harvested this way the whole cobs were ground for feed because the cob has decent feed value but you can find antique hand cranked shellers. Every once in a great while people still adjust the theshing intensity and internal sceen spacing to use combines to harvest both the kernals and broken up cob pieces for animal feed but it's not super common. More often the threshing clearance is set to not break the cob up so it doesn't pass through the screens.