Frigidaire freezer making intermittent grinding noise
A grinding noise audible in the cold compartment of a freezer or refrigerator is usually caused by ice buildup on the recirculator fan. The ice can be removed by removing the food and leaving the appliance off for 24 hours with the doors open. If the ice comes back inconveniently often then a door seal may be failing and allowing too much outside air to enter the compartments.

However the noise in your video could also be caused by a worn bearing in the recirculator fan. You'll know which problem you have once you have removed the ice. Of course the only cure for the bad bearing is to replace the fan.