If you go with a PC-based VMS (like Blue Iris, Sighthound, Milestone, etc), since they run on boxes with more processing power than most NAS/NVR setups, their built-in motion detection often has features more advanced than a camera's basic motion detection. For that reason, I'd really really really suggest keeping Dahua/Hik's advanced motion detection in mind when building out a surveillance system. Dahua and Hikvision are the brands that seem to get the newest low-light camera tech and it tends to stay with them exclusively until something better comes along, then the older stufft may trickle down to consumer brands like Amcrest, Lorex, etc. If you're going to be using outdoor cameras and you need ones that work the best in low-light, chances are high that you'll land on a Dahua Starlight+ or Hikvision Dark Fighter model. IVS/Smart Events helps reduce false alerts with a much less risk of missing real motion. The general issue with basic motion detection is that if you start getting a lot of false alerts you only have two options to tweak (sensitivity and threshold), and the usual conundrum is that once you tweak them to avoid the false alerts they're often set so low that they start missing real motion. If QVR Pro limits you to only using the camera's basic built-in motion detection, here's what you get to work with: Here's an example of some of the IVS motion detection abilities built into newer Dahua 'AI' series cameras:

Their newest cameras are starting to coming with 'AI' filters that will only trigger alarms if a vehicle and/or person is detected. Smart Events/IVS can significantly reduce false motion alarms. This is worth verifying, but it does NOT look like QVR Pro supports the separate advanced motion detection features built into Hikvision (called Smart Events) or Dahua (called IVS) cameras. So looks like if you're going to have more than two cameras, you'll be using the camera's built-in motion detection on at least some of them. The video mentions that if QVR Pro does the motion detection itself that it's limited to two cameras, presumably because of the load it would put on the processor. it can either use a camera's built-in motion detection or QVR Pro can do motion detection itself. It looks like QVR Pro handles motion detection the same way that Synology's Surveillance System app does. I was curious how QVR Pro handled motion detection so I watched the 'QNP351 - QVR Pro Guide - How to Setup Motion Detection' video on the link you posted above. Click to expand.Motion detection is a frequent reason folks will 'abandon ship' and jump from one surveillance system to another.

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