OnvifLib 1.1.1

OnvifLib

OnvifLib is a modern and lightweight .NET library for interacting with ONVIF-compliant IP cameras. It provides a simple interface to discover devices, control PTZ, retrieve media streams, and handle events over the ONVIF protocol.

📂 Source code: github.com/treealarm/OnvifLib — issues and pull requests welcome.

🚀 Features

• 🔍 Device discovery and information
• 🎥 Media profile and RTSP URI retrieval
• 🕹️ PTZ (Pan-Tilt-Zoom) camera control
• 📡 Event handling (PullPoint or Subscription)
• 🧠 Analytics (ver20): analytics modules and rules, metadata configuration (Profile M)
• 🎞️ Profile G: the camera's own recordings — search, replay and recording jobs
• 🔌 Device I/O: relay outputs and digital inputs
• 🔐 WS-Security (UsernameToken) support
• ✅ Targets .NET 10

📦 Installation

dotnet add package OnvifLib

⚡ Quick start

using OnvifLib;

// Create returns immediately and discovers the camera's services in the background.
var camera = Camera.Create("192.168.1.64", 80, "admin", "secret");
await camera.InitTask;

// A null service list means unreachable or unauthorized — Create itself never throws.
if (await camera.GetServicesAsync() is null)
    throw new InvalidOperationException("could not reach the camera");

var info = await camera.GetDeviceInformationAsync();
Console.WriteLine($"{info.Manufacturer} {info.Model}, firmware {info.FirmwareVersion}");

// Every Get*Service() returns null when the camera does not offer that service.
if (await camera.GetMediaService() is { } media)
{
    foreach (var profile in media.GetProfiles())
    {
        var uri = await media.GetStreamUri(profile.Token);
        Console.WriteLine($"{profile.Name} {profile.Width}x{profile.Height} {profile.Encoding} → {uri}");
    }

    // Snapshot bytes, or null (the failure is logged rather than thrown).
    if (await media.GetImage() is { } image)
        await File.WriteAllBytesAsync("snapshot.jpg", image.Data);
}

if (await camera.GetPtzService() is { } ptz)
{
    var profile = (await camera.GetProfiles())!.First();
    await ptz.ContinuousMoveAsync(profile.Token, panTiltX: 0.5f, panTiltY: 0f);
    await Task.Delay(500);
    await ptz.StopAsync(profile.Token);
}

Stream URIs come back exactly as the camera reported them, which is usually without credentials — a player needs user:password spliced in, percent-encoded.

To find cameras rather than address one directly:

var result = await WsDiscovery.ProbeAsync(TimeSpan.FromSeconds(4), CancellationToken.None);

// ScanOk distinguishes "scanned, found nothing" from "could not scan at all".
if (!result.ScanOk)
    Console.WriteLine("no interface could join the multicast group — check the firewall");

foreach (var device in result.Devices)
    Console.WriteLine($"{device.Name} at {device.Ip}:{device.Port}");

🧪 Samples

Two runnable applications live in samples/, both referencing the library directly:

dotnet run --project samples/OnvifLib.Probe -- --discovery
dotnet run --project samples/OnvifLib.Gui

In VS Code, press F5 and pick a configuration — the GUI, its self-test, or the probe with prompts for the address and credentials. In Visual Studio, set either sample as the startup project and pick a launch profile.

Note: do not enable trimming or NativeAOT in a consuming application. System.ServiceModel.* builds its channels, serializers and generated proxies by reflection with no trim annotations, so a trimmed build launches and then fails on the first SOAP call.