RTSP

RTSP (Real-Time Streaming Protocol) is a network control protocol that clients use to establish and control streaming media sessions with servers — most commonly, to pull live video from IP cameras into a VMS or AI analytics engine.

How It Works

RTSP is best understood as the "remote control" for a video stream, not the stream itself:

1. Connection. The client opens a TCP session to the camera on port 554 (default) and issues `DESCRIBE` to request the stream description (SDP).
2. Setup. `SETUP` negotiates how the media will be delivered — usually RTP over UDP or TCP.
3. Play. `PLAY` starts the stream. The actual video frames are delivered by RTP, not RTSP.
4. Teardown. `TEARDOWN` closes the session when the client is done.

A typical RTSP URL looks like: `rtsp://user:pass@192.168.1.100:554/stream1`

Modern systems often tunnel RTSP over TCP or HTTP for compatibility with firewalls and NATs.

Why It Matters

RTSP is the lingua franca of IP video:

• Universal support — every IP camera and VMS speaks RTSP.
• Low overhead — direct camera-to-server streaming without proprietary gateways.
• AI integration — analytics engines like IncoreSoft's VMS and VEZHA modules pull video via RTSP to run inference in real time.

Without RTSP, every camera-to-software connection would need a custom integration. With it, plugging in a new camera is a one-line URL change.

Use Cases

• VMS ingestion — cameras stream continuously to recording and analytics servers
• AI analytics — face recognition, ALPR, and object detection consume RTSP feeds
• Video walls — operator workstations display live RTSP streams
• Third-party integrations — mobile viewers, body-worn cameras, drones
• Transcoding and bridging — converting RTSP to WebRTC or HLS for browser clients

Frequently Asked Questions

What's the difference between RTSP and RTMP?

RTSP is a control protocol optimized for live, low-latency camera streams (usually used for ingestion). RTMP was designed for Flash-era delivery and is now mostly used for publishing streams to platforms like YouTube or Twitch.

Why does RTSP over TCP often work better than UDP?

UDP has lower latency in theory but gets blocked by many corporate firewalls and suffers packet loss over unreliable networks. RTSP-over-TCP adds small latency but is far more reliable in practice.

Can RTSP streams be encrypted?

Yes, via RTSPS (RTSP over TLS, port 322) or SRTP for the media payload. Many older cameras only support unencrypted RTSP, so network segmentation (VLANs, VPN) is often used as a compensating control.