Last updated: June 2026
The choice between RTSP (Real-Time Streaming Protocol) and RTMP (Real-Time Messaging Protocol) for CCTV video streaming determines compatibility with NVRs, viewing platforms, and smart home systems. Both protocols are used for live video from IP cameras, but they differ fundamentally in architecture, latency, and firewall traversal. UK installers who choose the wrong protocol for their application end up with buffering, compatibility issues, or latency that makes PTZ control impractical.
RTSP: The Camera Industry Standard
RTSP is the native streaming protocol for virtually all ONVIF-compliant IP cameras. It uses RTP (Real-Time Protocol) for video data and RTCP for control. RTSP establishes a direct client-server connection between the viewer and the camera, providing the lowest possible latency (typically 200–500 ms on a local network). The protocol supports multicast, allowing multiple viewers to access the same stream without duplicating bandwidth. However, RTSP does not traverse firewalls or NAT (Network Address Translation) well because it uses dynamic UDP ports for RTP traffic. This makes remote access through firewalls unreliable without additional configuration or a VPN.
RTMP: Designed for Streaming Platforms
RTMP was developed by Macromedia (now Adobe) for streaming to Flash-based platforms. It uses TCP, which reliably traverses firewalls and NAT on port 1935. RTMP is the protocol used by YouTube Live, Facebook Live, and many cloud CCTV platforms. However, RTMP is an older protocol with higher overhead than RTSP. Latency is typically 2–10 seconds depending on buffer settings and network conditions. RTMP is being deprecated by Adobe and replaced by SRT (Secure Reliable Transport) and WebRTC, but it remains widely supported because of its firewall-friendly TCP transport. RTMP encoding consumes slightly more camera CPU than RTSP encoding.
When to Use Each Protocol
For local NVR recording and home viewing on the same network, use RTSP. It provides the lowest latency, uses less bandwidth, and is the native protocol for every ONVIF camera. For streaming to cloud platforms such as YouTube, Facebook, or cloud NVR services, use RTMP if the camera supports it directly, or use an RTSP-to-RTMP relay server. For remote viewing through a firewall without a VPN, RTMP is more reliable because TCP on port 1935 passes through most firewalls without configuration. For smart home integration platforms like Home Assistant, RTSP is preferred for local streams and RTMP for cloud streams.
Emerging Protocols: SRT and WebRTC
SRT (Secure Reliable Transport) is the emerging replacement for RTMP. It uses UDP with built-in retransmission and encryption, providing lower latency (500 ms–2 seconds) than RTMP with better firewall traversal than RTSP. Many new IP cameras and NVRs now support SRT directly. WebRTC is the lowest latency option available (sub-100 ms) but requires a signalling server for connection establishment and is currently supported on few CCTV cameras directly. For new installations where low-latency remote streaming is required, choose cameras that support SRT. For legacy systems, RTMP remains the most compatible option for cloud streaming.
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Frequently Asked Questions
1. What is the difference between RTSP and RTMP for CCTV?
Answer: RTSP is the standard camera protocol with low latency (200–500 ms) but poor firewall traversal. RTMP uses TCP, traverses firewalls reliably, but has higher latency (2–10 seconds) and overhead. For more detail, see How to install CCTV for Self Storage Facilities - UK step by step guide 2026. Also read our related guide: Frame Rate vs AI Detection: The FPS Sweet Spot. Browse our security technology hub at Uni Blog Security Hub. Official UK guidance on this topic: Surrey Security Centre.
2. Which streaming protocol has the lowest latency?
Answer: RTSP over a local network has the lowest latency at 200–500 ms. WebRTC is lower at sub-100 ms but has limited camera support. RTMP is the highest at 2–10 seconds. For more detail, see How much does Care Homes and Assisted Living CCTV cost in 2026? UK prices explained. Also read our related guide: Dual-Lens Cameras: Wide + Telephoto Benefits.
3. Can I stream my CCTV cameras to YouTube?
Answer: Yes, if the camera supports RTMP streaming. Configure the camera to stream to YouTube’s RTMP ingest URL. Alternatively, use a PC or NVR with RTSP-to-RTMP relay software. For more detail, see Does Construction Sites CCTV reduce insurance premiums in 2026? UK guide. Also read our related guide: ePoE vs Standard PoE: Extended Reach for CCTV.
4. Does RTMP use more bandwidth than RTSP?
Answer: RTMP has approximately 5–10% more overhead than RTSP due to its TCP-based transport and additional metadata. For a 10 Mbps stream, RTMP uses approximately 10.5–11 Mbps. For more detail, see Future of False Alarm Reduction CCTV in 2026 - UK trends and technology. Also read our related guide: Audio Analytics Limits: Glass Break and Gunshot Detection.
5. Is RTSP suitable for remote CCTV viewing?
Answer: RTSP works for remote viewing through a VPN, which provides secure firewall traversal. Direct RTSP through a firewall is unreliable due to dynamic UDP port allocation. Use RTMP or SRT for direct remote access. Also read our related guide: Alexa and Google Home CCTV Integration Quirks.
Conclusion
The difference between a security system that works and one that frustrates is understanding the real-world behaviour of cameras, cables, and the environment they operate in. Manufacturers sell specifications. Installers solve problems. The questions above represent the issues that UK homeowners and businesses actually face — the ones the spec sheets do not mention.
Article by Gary Pearce, qualified security systems engineer. For a free security assessment, visit gary-pearce-home-services.pages.dev. This guide was last updated June 2026. Verify current UK regulations with the ICO.