How it is calculated
Storage = bitrate × time × cameras. A typical 4 MP H.264 stream at 25 fps is about 6 Mbit/s; H.265 compresses about twice as well, and 15 fps instead of 25 saves another third. If you know the bitrate from the camera settings, enter it for an exact figure. Motion recording usually runs 20–40 % of the time, though IR noise and trees in the wind trigger it more at night.
For recording use surveillance drives (WD Purple, Seagate SkyHawk) rated for 24/7 writes. Your own NVR with Frigate: Frigate generator; camera power: PoE calculator.
WD Purple: AliExpress · Seagate SkyHawk: AliExpress
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