Each camera has its own analog connection wire. I am looking for a dvr box that I can connect to a home server and run something like Shinobi. I currently have this dvr box https://ellipsesecurity.com/product/hdtvi08b-tru-view-hd-tvi-8-channel-hd-security-dvr/ , but i don’t think it can automatically forward video to a home server
1tb gives me about a week of full record for 6 2K cameras, but motion captures seem to be more. You can switch the disk out fairly easily as well. So you should be find with 4 cameras and 1TB.