The video captured by your cameras is analyzed and encrypted on your home hub device (Upgrade to the new Home architecture.
View video
Go to the Home app
on your Mac.Click the camera tile, then click
on your Mac.Click the camera tile, then click
in the top-right corner.
When you set up a camera to detect specific motion, the timeline displays unique symbols for people, animals, vehicles, and package delivery.
Note: If there are more cameras in your home than can have their video analyzed at one time by your home hubs, some video captured may not be analyzed. Clips are still recorded, but will show a 
Click Add Zone when you’ve outlined the area you want to record.
To exclude the outlined area and record everything outside it, click Invert Zone.
Click Done, then click 
, then click Apple Support article: Get notifications for your HomeKit accessories