...but I don't know/play football so...
No, that is someone underneath him.
Looks Half-in, Half-out to me...
If any part of the ball breaks the plane of the end zone it is a touchdown. So half in, half out is a td.
If any part, not the whole, of the ball passes the plane of the field side of the goal line it's a TD. The goal line is in the end zone.