RTSP is a network protocol for controlling streaming media, commonly used to pull video from an IP camera. A client opens a session to the camera’s stream address, and the video travels over the companion transport protocol. Most recorders and analytics tools accept an RTSP address.
RTSP is the common language between a camera and whatever wants its video. It moves the stream; it does not make the stream private.
Stream addresses and sessions
Each camera exposes a stream path by model and channel, and the recorder stores that address. Sessions are negotiated, so a tool that accepts RTSP can often use a camera whose own management software it does not support.
Security and network design
Plain RTSP is unencrypted, so a stream crossing another network can be read. Keep camera streams on a dedicated segment, prefer encrypted variants where both ends support them, and restrict which hosts may request a stream.