Weird stepper motor behaviour on RAMPS in arduino
The video you show shows movement of far more than 1mm.  This indicates that the steps per unit is far different than you are configuring the Marlin software for.  With a +/-1mm and 212 steps per mm, there should have been 212 steps sent to your stepper.

Recalculate your steps/mm values and slow down the feed rate to get something reliable.  

For experimenting, in Pronterface, set the feedrate of 10mm/sec (600mm/min) or 1mm/sec (60mm/min) to slow things down so you can hear or count the steps with your ear, then choose smaller steps, like +0.1mm and see if you get the planned displacement.  If, at a really slow speed, you don't get the corresponding movement, then your steps/mm need adjustment to match your system.  

Eyeballing it, I'd say the called-for 1mm or 212 steps is moving the stage about 10mm, so you would need numbers more like this for the x and y axes:

#define DEFAULT_AXIS_STEPS_PER_UNIT {21 ,21 ,8034.69,196.52}