I don't need video(s) to understand the subject here : I just use an image search :
https://duckduckgo.com/?q=%2B%22Hyundai+Uni+Wheel%22&t=ofa&iar=images&iax=images&ia=images
This is a mechanical device that allows coupling of any wheels of any vehicles to any electric motor.
it is designed in such a way to permit vertical movement of the wheel without the need of such movement of the motor. So basically it is a new type of suspension.
Since it needs many gears in a row for the transit of mechanical energy it will incure an inefficiency factor.