There’s a few. You can search for “open source security camera” to find them.

The reason I’m building mine, instead of going with another solution is because I have a hard requirement that if all of my devices are offline, destroyed, or stolen, I want to still be able to see my videos (so cloud storage is required), and I want everything that goes into the cloud to be end to end encrypted.

That basically means everything necessary to view videos has to be stored in the cloud except the decryption password. So anything with a local database or unencrypted storage is out.

Some existing systems support some of those requirements, but afaik, there aren’t any that support all of the above (at least not easily). With Soteria and Nephele, if all of your cameras are offline and your WebDAV server is offline, you can just spin up a local WebDAV server with your S3 info, and you’ve got a working client to view all of your footage.

Having that can really help when something goes wrong. For example, I currently use Google Nest cams, and I was able to tell why my cameras went offline while I was away when the camera caught the transformer down the street blowing up right before the video cut out.