How to implement centralized output of images from CCTV cameras?

Question

Computer networks

Good afternoon, dear Toaster users. Recently, I was given a rather interesting task, here's the gist:
There are three buildings, each of which has a video surveillance system. An iTV Intellect system is operating in one building, the image is displayed on the computer screen through the iTV application configured to the server's IP address. The server and computer are in a separate VLAN, access to the Internet is limited.
In the other two buildings, the situation is almost the same, but not iTV, but the RVi system is used. The network, accordingly, is also disconnected from the Internet.
The management now needed to collect a "picture" from all the buildings in one building. How it is more correct to make it? If cameras are accessed from a browser by IP address, then it is simply necessary to give the VLAN access to the Internet, and then forward the port and access it remotely, or is there a more elegant solution?

Answer 1

Start a stream via RTSP from RVI registrars to ITV. Did. Works. Buildings can be connected via VPN via Mikrotik. There are already ready-made working projects of a similar plan.