Video Calibration allows you to more accurately identify people and objects, by first taking 5 photos to set as reference. If it is your first time setting up a Video Object Detection rule you will have to calibrate the camera. Not all cameras can be calibrated, only the Premium Indoor Camera ADC-V622 and Outdoor Camera ADC-V723 require it.
If the camera is moved after it was calibrated, we recommend recreating the Video Object Detection rule and re-calibrating from the new location in the Settings section.