ZoneMinder - Security camera Server
Maybe ClearOS could add this function as well. Elastix has that option. I can get cheap pci cards for around 200 bucks but a DVR costs over 1000 here, but then I’d have to have another extra server and so on.
I used to run ZoneMinder and it installed cleanly and has its own web interface. Installation instructions are at https://zmrepo.zoneminder.com/