ONVIF (Open Network Video Interface Forum) is an industry standard that enables IP cameras from different manufacturers to communicate with compatible software using a common protocol. SmartRTSP uses ONVIF to automatically discover cameras on your local network — no manual IP entry or RTSP URL required.
Before ONVIF, connecting a camera to third-party software meant hunting for a proprietary SDK or manually entering URLs and credentials. ONVIF solved this by defining a shared set of web services — based on open standards like SOAP and WS-Discovery — that any camera or viewer can implement. The result is true plug-and-play interoperability across brands.
What is ONVIF?
ONVIF was founded in 2008 by three companies — Axis Communications, Bosch Security Systems, and Sony — with the goal of creating an open interface standard for physical security products. Today it has over 500 member companies and its specifications are implemented in hundreds of millions of IP cameras worldwide.
The standard defines how IP cameras expose their capabilities through web services. A compliant camera publishes a set of XML endpoints that describe what it can do: stream live video, report its model and firmware version, support PTZ (pan-tilt-zoom) controls, handle analytics events, and more. Any ONVIF-compatible application can query these endpoints and interact with the camera in a predictable, vendor-neutral way.
ONVIF organises its features into Profiles — each profile defines a minimum set of mandatory capabilities a device must implement to claim conformance with that profile.
How ONVIF Discovery Works
The discovery mechanism behind ONVIF is called WS-Discovery (Web Services Dynamic Discovery), an OASIS standard for finding services on a local network. When SmartRTSP scans your network, it sends a WS-Discovery multicast probe UDP packet to the reserved address 239.255.255.250:3702.
Every ONVIF-compliant camera on the same subnet receives this probe and responds with a unicast message identifying itself — its device type, ONVIF service endpoint URL, and a unique device UUID. SmartRTSP then contacts each responding camera's ONVIF endpoint and calls the GetProfiles and GetStreamUri web service methods to retrieve the camera's live RTSP stream URL automatically.
ONVIF Profiles Explained
ONVIF organises features into Profiles. A camera claiming a specific profile must implement all mandatory capabilities defined for that profile.
| Profile | Focus Area | Key Capabilities | Common Use |
|---|---|---|---|
| Profile S | Basic streaming | Live video/audio via RTSP, PTZ control, relay outputs | Most IP cameras |
| Profile G | Storage & recording | Onboard recording, playback, track search, schedule management | NVRs, cameras with SD card |
| Profile T | Advanced video | H.265/HEVC, HTTPS streaming, metadata, image settings | Modern IP cameras |
| Profile A | Access control | Door access points, credential management, access rules | Door entry systems |
| Profile C | Door control | Door interlock, alarm input/output, access control integration | Access control systems |
For live camera viewing, Profile S and Profile T are the relevant profiles. Profile G is used when accessing recorded footage stored on the camera or NVR.
ONVIF vs RTSP — What's the Difference?
ONVIF and RTSP are complementary technologies that work together — not alternatives to each other. Understanding their distinct roles clears up a common source of confusion:
ONVIF is the "phone book and configuration panel." It lets an app find the camera, query its model and capabilities, retrieve its RTSP URL, and adjust settings like resolution, frame rate, and PTZ position — all through standardised XML web service calls over HTTP.
RTSP is the "video pipe." Once the app knows the camera's RTSP URL (found via ONVIF or entered manually), it uses RTSP to open a connection and receive the encoded H.264 or H.265 video stream in real time over the local network.
In practice: SmartRTSP uses ONVIF's WS-Discovery to find cameras and GetStreamUri to retrieve the RTSP URL, then switches to RTSP/RTP for the actual video stream. If you add a camera manually, you skip the ONVIF step and go straight to RTSP.
How SmartRTSP Uses ONVIF
SmartRTSP's ONVIF scan is designed to make adding cameras as fast as possible. Here is exactly what happens when you tap the scan button:
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Tap the scan icon. SmartRTSP immediately sends a WS-Discovery multicast UDP probe to your local subnet. No configuration required.
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Cameras respond within milliseconds. Each ONVIF camera on the network sends back its service endpoint URL. The app waits up to 3–5 seconds to collect all responses.
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Capabilities and stream URL fetched. SmartRTSP calls GetDeviceInformation and GetStreamUri for each camera, retrieving the model name, manufacturer, and ready-to-use RTSP URL.
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Camera added, streaming begins. Tap any discovered camera to add it. The RTSP URL is pre-filled. Enter your credentials once and SmartRTSP starts displaying the live stream immediately.
Note: your iPhone or Mac must be on the same Wi-Fi network as the cameras for ONVIF discovery to work. WS-Discovery multicast does not cross router boundaries.