RTSP
The open streaming protocol that lets IP cameras share their video feed over a local network with any compatible software.
RTSP, or Real Time Streaming Protocol, is the open standard that IP cameras use to broadcast their video feed over a local network.
Why it matters for self hosting
A camera with RTSP support is an open camera. Any software that speaks the protocol can connect to it and pull the stream directly, with no manufacturer app, no cloud account, and no dependency on a third party server. A camera without RTSP is closed: the footage goes through the vendor's infrastructure, on their terms.
This distinction is what makes a self hosted home security setup viable. When a camera exposes an RTSP stream, you decide what receives it, where it is stored, and what analyses it.
A concrete example
The Reolink 2K+ Video Doorbell broadcasts an RTSP stream over the local network. Frigate connects to that stream, processes every frame locally for object detection, and stores footage on your own hardware. Nothing leaves the network unless you choose to send it somewhere.
That combination is only possible because the camera speaks RTSP. See Network Video Recording for how the full recording pipeline fits together.