Frigate is popular.
I used to use ZoneMinder, it worked well, but you must be very familiar with onvif, primary/secondary channels, and key frames for it to work well.
I only switched to frigate because of the person/animal detection. It’s ok, but it does need some polish in a few areas like event retention, and it could stand some more approachable documentation.


You should check out the nas compares review of the pre-release, it’s insanely expensive and he questions who exactly is the target audience.
Beyond that, he reviews the specs quite nicely (as usual).