Your movies will have a whirring sound that is similar to the sound of a hard drive in your laptop . .

Bag should have storage areas for many extra SD cards, 2 extra batteries, and indelible ink to label filled SD cards if you store them instead of reusing (wise to store as flash technology is more stable than hard drives which can die at any time.

How many 6TB hard drives do you need to have a good video collection?

It sounds almost like a computer hard drive clicking

However, if SD card is not fully filled and you fill them fully to retain them as flash backup beyond that which you download to PC hard drive which can fail, you may wish to buy these overprices holsters as they provide rapid access without searching for bag that you don't need close by as your battery was fully