Multi-Camera RTSP Grid — 4×4 NVR Wall in C# / .NET¶

using System;
using System.Threading.Tasks;
using VisioForge.Core.MediaBlocks;
using VisioForge.Core.MediaBlocks.AudioRendering;
using VisioForge.Core.MediaBlocks.Sources;
using VisioForge.Core.MediaBlocks.VideoRendering;
using VisioForge.Core.Types;
using VisioForge.Core.Types.Events;
using VisioForge.Core.Types.X.Sources;

public class RTSPPlayEngine : IAsyncDisposable
{
    private MediaBlocksPipeline _pipeline;
    private VideoRendererBlock _videoRenderer;
    private AudioRendererBlock _audioRenderer;
    private RTSPSourceBlock _source;
    private bool _disposed;

    public event EventHandler<ErrorsEventArgs> OnError;

    public RTSPPlayEngine(RTSPSourceSettings rtspSettings, IVideoView videoView)
    {
        _pipeline = new MediaBlocksPipeline();
        _pipeline.OnError += (s, e) => OnError?.Invoke(this, e);

        _source = new RTSPSourceBlock(rtspSettings);
        _videoRenderer = new VideoRendererBlock(_pipeline, videoView) { IsSync = false };
        _pipeline.Connect(_source.VideoOutput, _videoRenderer.Input);

        if (rtspSettings.AudioEnabled)
        {
            _audioRenderer = new AudioRendererBlock() { IsSync = false };
            _pipeline.Connect(_source.AudioOutput, _audioRenderer.Input);
        }
    }

    // Start the pipeline in paused state (used for synchronized start)
    public Task<bool> PreloadAsync() => _pipeline.StartAsync(true);

    // Start playing immediately (non-synchronized use)
    public Task<bool> StartAsync() => _pipeline.StartAsync();

    // Resume a pipeline that was preloaded
    public Task ResumeAsync() => _pipeline.ResumeAsync();

    public Task<bool> StopAsync() => _pipeline.StopAsync(true);

    public bool IsPaused() => _pipeline.State == PlaybackState.Pause;
    public bool IsStarted() => _pipeline.State == PlaybackState.Play;

    public async ValueTask DisposeAsync()
    {
        if (_disposed) return;
        _disposed = true;

        if (_pipeline != null)
        {
            await _pipeline.DisposeAsync();
            _pipeline = null;
        }

        _videoRenderer?.Dispose();
        _audioRenderer?.Dispose();
        _source?.Dispose();
    }
}

using System;
using System.Threading.Tasks;
using System.Windows;
using VisioForge.Core;
using VisioForge.Core.Types.X.Sources;

public partial class MainWindow : Window
{
    private const int GridSize = 4;
    private readonly RTSPPlayEngine[] _engines = new RTSPPlayEngine[GridSize * GridSize];
    private readonly IVideoView[] _views;

    // 16 RTSP URLs — replace with your own. ONVIF service URLs work too;
    // RTSPSourceSettings.CreateAsync will resolve them to RTSP internally.
    private static readonly string[] Urls =
    {
        "rtsp://192.168.1.101:554/stream1", "rtsp://192.168.1.102:554/stream1",
        "rtsp://192.168.1.103:554/stream1", "rtsp://192.168.1.104:554/stream1",
        "rtsp://192.168.1.105:554/stream1", "rtsp://192.168.1.106:554/stream1",
        "rtsp://192.168.1.107:554/stream1", "rtsp://192.168.1.108:554/stream1",
        "rtsp://192.168.1.109:554/stream1", "rtsp://192.168.1.110:554/stream1",
        "rtsp://192.168.1.111:554/stream1", "rtsp://192.168.1.112:554/stream1",
        "rtsp://192.168.1.113:554/stream1", "rtsp://192.168.1.114:554/stream1",
        "rtsp://192.168.1.115:554/stream1", "rtsp://192.168.1.116:554/stream1",
    };

    public MainWindow()
    {
        InitializeComponent();
        _views = new IVideoView[]
        {
            videoView00, videoView01, videoView02, videoView03,
            videoView10, videoView11, videoView12, videoView13,
            videoView20, videoView21, videoView22, videoView23,
            videoView30, videoView31, videoView32, videoView33,
        };
    }

    private async void Window_Loaded(object sender, RoutedEventArgs e)
    {
        await VisioForgeX.InitSDKAsync();
    }

    private async void btStart_Click(object sender, RoutedEventArgs e)
    {
        await DestroyAllAsync();

        // 1. Build sources and engines in parallel.
        var createTasks = new Task[GridSize * GridSize];
        for (int i = 0; i < _engines.Length; i++)
        {
            int idx = i;
            createTasks[i] = Task.Run(async () =>
            {
                var settings = await RTSPSourceSettings.CreateAsync(
                    new Uri(Urls[idx]), login: "admin", password: "admin123",
                    audioEnabled: false);

                settings.LowLatencyMode = true;          // minimise jitter buffer
                settings.UseGPUDecoder  = true;          // offload H.264 to GPU

                var engine = new RTSPPlayEngine(settings, _views[idx]);
                engine.OnError += (s, err) =>
                    Dispatcher.Invoke(() =>
                        System.Diagnostics.Debug.WriteLine($"cam[{idx}]: {err.Message}"));
                _engines[idx] = engine;
            });
        }
        await Task.WhenAll(createTasks);

        // 2. Preload every pipeline into the Paused state.
        await Task.WhenAll(Array.ConvertAll(_engines, en => en.PreloadAsync()));

        // 3. Wait until all pipelines report Paused.
        for (int tries = 0; tries < 100; tries++)   // 100 × 50 ms = 5 s max
        {
            bool allPaused = true;
            foreach (var en in _engines)
                if (!en.IsPaused()) { allPaused = false; break; }
            if (allPaused) break;
            await Task.Delay(50);
        }

        // 4. Resume all simultaneously — frame-aligned start across 16 cells.
        foreach (var en in _engines)
            await en.ResumeAsync().ConfigureAwait(false);
    }

    private async void btStop_Click(object sender, RoutedEventArgs e) => await DestroyAllAsync();

    private async Task DestroyAllAsync()
    {
        for (int i = 0; i < _engines.Length; i++)
        {
            if (_engines[i] != null)
            {
                await _engines[i].DisposeAsync();
                _engines[i] = null;
            }
        }
    }

    private async void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
    {
        await DestroyAllAsync();
        VisioForgeX.DestroySDK();
    }
}

using SkiaSharp.Views.Maui.Controls.Hosting;
using VisioForge.Core.UI.MAUI;

public static class MauiProgram
{
    public static MauiApp CreateMauiApp()
    {
        var builder = MauiApp.CreateBuilder();
        builder
            .UseMauiApp<App>()
            .UseSkiaSharp()
            .ConfigureMauiHandlers(handlers => handlers.AddVisioForgeHandlers())
            .ConfigureFonts(fonts =>
            {
                fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
            });

        return builder.Build();
    }
}

using VisioForge.Core;
using VisioForge.Core.Types;
using VisioForge.Core.Types.X.Sources;

public partial class MainPage : ContentPage
{
    private const int GridSize = 4;
    private readonly RTSPPlayEngine[] _engines = new RTSPPlayEngine[GridSize * GridSize];
    private IVideoView[] _views;

    private static readonly string[] Urls =
    {
        "rtsp://192.168.1.101:554/stream1", /* ...15 more... */
    };

    public MainPage()
    {
        InitializeComponent();
        _views = new IVideoView[]
        {
            cam00.GetVideoView(), cam01.GetVideoView(), cam02.GetVideoView(), cam03.GetVideoView(),
            cam10.GetVideoView(), cam11.GetVideoView(), cam12.GetVideoView(), cam13.GetVideoView(),
            cam20.GetVideoView(), cam21.GetVideoView(), cam22.GetVideoView(), cam23.GetVideoView(),
            cam30.GetVideoView(), cam31.GetVideoView(), cam32.GetVideoView(), cam33.GetVideoView(),
        };

        VisioForgeX.InitSDK();
    }

    private async void OnStartClicked(object sender, EventArgs e)
    {
        await DestroyAllAsync();

        var createTasks = new Task[GridSize * GridSize];
        for (int i = 0; i < _engines.Length; i++)
        {
            int idx = i;
            createTasks[i] = Task.Run(async () =>
            {
                var settings = await RTSPSourceSettings.CreateAsync(
                    new Uri(Urls[idx]), "admin", "admin123", audioEnabled: false);

                settings.LowLatencyMode = true;
                settings.UseGPUDecoder  = true;

                _engines[idx] = new RTSPPlayEngine(settings, _views[idx]);
            });
        }
        await Task.WhenAll(createTasks);

        await Task.WhenAll(Array.ConvertAll(_engines, en => en.PreloadAsync()));

        for (int tries = 0; tries < 100; tries++)
        {
            bool allPaused = true;
            foreach (var en in _engines)
                if (!en.IsPaused()) { allPaused = false; break; }
            if (allPaused) break;
            await Task.Delay(50);
        }

        foreach (var en in _engines)
            await en.ResumeAsync().ConfigureAwait(false);
    }

    private async void OnStopClicked(object sender, EventArgs e) => await DestroyAllAsync();

    private async Task DestroyAllAsync()
    {
        for (int i = 0; i < _engines.Length; i++)
        {
            if (_engines[i] != null)
            {
                await _engines[i].DisposeAsync();
                _engines[i] = null;
            }
        }
    }
}

engine.OnError += (s, err) =>
{
    // Per-camera log. Marshal to UI thread if you update UI here.
    Dispatcher.Invoke(() => LogLine($"cam[{idx}] error: {err.Message}"));
};

settings.FallbackSwitch = new FallbackSwitchSettings
{
    // Image/text settings — see the FallbackSwitch docs for options.
};