Fix CameraStreamState.Failed compile error (19041 projection omits enum member names — compare by int); fix first-frame proof test (no dispatcher = no bitmap, assert LatestFrame instead)

Services/MediaCaptureFrameSource.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Runtime.InteropServices;
 using System.Runtime.InteropServices.WindowsRuntime;
@@ -6,6 +7,7 @@ using System.Threading.Tasks;
 using Windows.Graphics.Imaging;
 using Windows.Media.Capture;
 using Windows.Media.Capture.Frames;
+using Windows.Media.Devices;
 using Windows.Media.MediaProperties;
 using ytLive.Helpers;
 
@@ -16,17 +18,28 @@ namespace ytLive.Services;
 /// preview source; the capture pipeline does any format conversion, so every
 /// frame arrives as a normalized <see cref="VideoFrame"/>. Frames arrive on a
 /// worker thread — marshal before touching WPF.
+///
+/// Allocation is validated, never taken on faith: after <c>InitializeAsync</c>
+/// the bound device, its frame sources, and its stream properties are checked,
+/// the frame reader's start status is read (not swallowed), and the live
+/// state signals (<c>Failed</c>, <c>CameraStreamStateChanged</c>) are subscribed
+/// so an async death surfaces as <see cref="SourceFailed"/> instead of a silent
+/// empty preview.
 /// </summary>
 public sealed class MediaCaptureFrameSource : ICameraFrameSource
 {
     private readonly string _deviceId;
     private MediaCapture? _capture;
     private MediaFrameReader? _frameReader;
+    private string? _lastError;
+    private bool _isFailed;
 
     public string DeviceId => _deviceId;
 
     public event Action<VideoFrame>? FrameAvailable;
 
+    public event Action<string>? SourceFailed;
+
     public MediaCaptureFrameSource(string deviceId)
     {
         _deviceId = deviceId;
@@ -34,47 +47,15 @@ public sealed class MediaCaptureFrameSource : ICameraFrameSource
 
     public async Task StartAsync()
     {
-        var capture = new MediaCapture();
+        // Fallback ladder: prefer the camera's VideoPreview stream, but if the
-        MediaFrameReader? reader = null;
+        // reader refuses to start there (NoVideoFrameAvailable), retry against
-        try
+        // its VideoRecord stream — some devices only deliver through it.
+        // (MediaCaptureSharingMode.Exclusive is not projected by the 19041 SDK.)
+        if (!await TryStartAsync(preferVideoRecord: false))
         {
-            var settings = new MediaCaptureInitializationSettings
+            if (!await TryStartAsync(preferVideoRecord: true))
-            {
-                VideoDeviceId = _deviceId,
-                StreamingCaptureMode = StreamingCaptureMode.Video,
-                MemoryPreference = MediaCaptureMemoryPreference.Cpu,
-                SharingMode = MediaCaptureSharingMode.SharedReadOnly,
-            };
-            await capture.InitializeAsync(settings);
-
-            var colorSource = capture.FrameSources.Values
-                .OrderBy(s => s.Info.MediaStreamType == MediaStreamType.VideoPreview ? 0 : 1)
-                .FirstOrDefault(s => s.Info.MediaStreamType is MediaStreamType.VideoPreview or MediaStreamType.VideoRecord);
-            if (colorSource == null)
-            {
-                var kinds = string.Join(", ", capture.FrameSources.Values
-                    .Select(s => s.Info.MediaStreamType).Distinct());
                 throw new InvalidOperationException(
-                    $"Camera '{_deviceId}' exposes no video source (found: {kinds}). " +
+                    _lastError ?? $"Camera '{_deviceId}' could not be started.");
-                    "It may be locked by another app (e.g. NVIDIA Broadcast).");
-            }
-
-            reader = await capture.CreateFrameReaderAsync(colorSource, MediaEncodingSubtypes.Bgra8);
-            reader.FrameArrived += OnFrameArrived;
-            await reader.StartAsync();
-
-            _capture = capture;
-            _frameReader = reader;
-        }
-        catch
-        {
-            if (reader != null)
-            {
-                reader.FrameArrived -= OnFrameArrived;
-                reader.Dispose();
-            }
-            capture.Dispose();
-            throw;
         }
     }
 
@@ -98,7 +79,134 @@ public sealed class MediaCaptureFrameSource : ICameraFrameSource
 
         var capture = _capture;
         _capture = null;
-        capture?.Dispose();
+        if (capture != null)
+        {
+            UnsubscribeCaptureEvents(capture);
+            capture.Dispose();
+        }
+    }
+
+    private async Task<bool> TryStartAsync(bool preferVideoRecord)
+    {
+        MediaCapture? capture = null;
+        MediaFrameReader? reader = null;
+        try
+        {
+            capture = new MediaCapture();
+            var settings = new MediaCaptureInitializationSettings
+            {
+                VideoDeviceId = _deviceId,
+                StreamingCaptureMode = StreamingCaptureMode.Video,
+                MemoryPreference = MediaCaptureMemoryPreference.Cpu,
+                SharingMode = MediaCaptureSharingMode.SharedReadOnly,
+            };
+            await capture.InitializeAsync(settings);
+
+            // Post-init resource validation: the capture must actually be bound to
+            // the device we asked for and must expose a live video controller.
+            if (!string.Equals(capture.MediaCaptureSettings?.VideoDeviceId, _deviceId,
+                    StringComparison.OrdinalIgnoreCase))
+                throw new InvalidOperationException(
+                    $"Camera '{_deviceId}' initialized but bound a different device.");
+
+            var colorSource = capture.FrameSources.Values
+                .OrderBy(s => preferVideoRecord
+                    ? (s.Info.MediaStreamType == MediaStreamType.VideoRecord ? 0 : 1)
+                    : (s.Info.MediaStreamType == MediaStreamType.VideoPreview ? 0 : 1))
+                .FirstOrDefault(s => s.Info.MediaStreamType is MediaStreamType.VideoPreview or MediaStreamType.VideoRecord);
+            if (colorSource == null)
+            {
+                var kinds = string.Join(", ", capture.FrameSources.Values
+                    .Select(s => s.Info.MediaStreamType).Distinct());
+                throw new InvalidOperationException(
+                    $"Camera '{_deviceId}' exposes no video source (found: {kinds}). " +
+                    "It may be locked by another app (e.g. NVIDIA Broadcast).");
+            }
+
+            // The device must answer for its preview stream — a dead, suspended, or
+            // locked device returns no stream properties even after "successful" init.
+            IReadOnlyList<IMediaEncodingProperties>? previewProps;
+            try
+            {
+                previewProps = capture.VideoDeviceController?
+                    .GetAvailableMediaStreamProperties(MediaStreamType.VideoPreview);
+            }
+            catch
+            {
+                previewProps = null;
+            }
+            if (previewProps == null || previewProps.Count == 0)
+                throw new InvalidOperationException(
+                    $"Camera '{_deviceId}' answered no video stream properties (offline, suspended, or locked).");
+
+            // The OS's live state signals: async failures must surface, not vanish.
+            capture.Failed += OnCaptureFailed;
+            capture.CameraStreamStateChanged += OnCameraStreamStateChanged;
+
+            reader = await capture.CreateFrameReaderAsync(colorSource, MediaEncodingSubtypes.Bgra8);
+            if (reader == null)
+                throw new InvalidOperationException($"Camera '{_deviceId}' created no frame reader.");
+
+            reader.FrameArrived += OnFrameArrived;
+            var status = await reader.StartAsync();
+            if (status != MediaFrameReaderStartStatus.Success)
+                throw new InvalidOperationException(
+                    $"Camera '{_deviceId}' frame reader refused to start: {status}.");
+
+            _capture = capture;
+            _frameReader = reader;
+            _lastError = null;
+            _isFailed = false;
+            return true;
+        }
+        catch (Exception ex)
+        {
+            _lastError = ex.Message;
+            if (reader != null)
+            {
+                reader.FrameArrived -= OnFrameArrived;
+                reader.Dispose();
+            }
+            if (capture != null)
+            {
+                UnsubscribeCaptureEvents(capture);
+                capture.Dispose();
+            }
+            return false;
+        }
+    }
+
+    private void UnsubscribeCaptureEvents(MediaCapture capture)
+    {
+        capture.Failed -= OnCaptureFailed;
+        capture.CameraStreamStateChanged -= OnCameraStreamStateChanged;
+    }
+
+    private void OnCaptureFailed(MediaCapture sender, MediaCaptureFailedEventArgs args)
+        => RaiseFailure($"capture failed ({args.Code}): {args.Message}");
+
+    private void OnCameraStreamStateChanged(MediaCapture sender, object args)
+    {
+        // CameraStreamState enum (Windows.Media.Devices): 0=NotStreaming, 1=Streaming,
+        // 2=Failed, 3=Shutdown. The 19041 SDK projection omits member names, so
+        // compare by value — the enum type itself resolves via the property return.
+        if ((int)sender.CameraStreamState == 2) // Failed
+            RaiseFailure("camera stream state is Failed");
+    }
+
+    private void RaiseFailure(string message)
+    {
+        if (_isFailed) return;
+        _isFailed = true;
+        AppLog.Write($"MediaCaptureFrameSource: {message}");
+        try
+        {
+            SourceFailed?.Invoke(message);
+        }
+        catch (Exception ex)
+        {
+            AppLog.Write($"MediaCaptureFrameSource: SourceFailed handler threw: {ex.Message}");
+        }
     }
 
     private void OnFrameArrived(MediaFrameReader sender, MediaFrameArrivedEventArgs args)

ytLive.Tests/CameraManagerTests.cs

@@ -1,3 +1,6 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
 using Xunit;
 using ytLive.Services;
 
@@ -9,20 +12,28 @@ public class CameraManagerTests
     {
         private readonly List<string> _started;
         private readonly List<string> _stopped;
+        private readonly VideoFrame? _pumpOnStart;
+        private readonly string? _failOnStart;
 
         public string DeviceId { get; }
         public event Action<VideoFrame>? FrameAvailable;
+        public event Action<string>? SourceFailed;
 
-        public FakeFrameSource(string deviceId, List<string> started, List<string> stopped)
+        public FakeFrameSource(string deviceId, List<string> started, List<string> stopped,
+            VideoFrame? pumpOnStart = null, string? failOnStart = null)
         {
             DeviceId = deviceId;
             _started = started;
             _stopped = stopped;
+            _pumpOnStart = pumpOnStart;
+            _failOnStart = failOnStart;
         }
 
         public Task StartAsync()
         {
+            if (_failOnStart != null) throw new InvalidOperationException(_failOnStart);
             _started.Add(DeviceId);
+            if (_pumpOnStart != null) FrameAvailable?.Invoke(_pumpOnStart);
             return Task.CompletedTask;
         }
 
@@ -33,29 +44,15 @@ public class CameraManagerTests
         }
 
         public void Pump(VideoFrame frame) => FrameAvailable?.Invoke(frame);
+        public void Fail(string message) => SourceFailed?.Invoke(message);
     }
 
-    private sealed class FailingFrameSource : ICameraFrameSource
+    // The refcount/coalescing tests model a camera whose frame pump is driven by
-    {
+    // the test after acquire, so they skip the first-frame proof (TimeSpan.Zero);
-        public string DeviceId { get; }
+    // the proof itself is exercised by the dedicated tests below.
-        public event Action<VideoFrame>? FrameAvailable;
-        public bool Stopped;
-
-        public FailingFrameSource(string deviceId) => DeviceId = deviceId;
-
-        public Task StartAsync() => throw new InvalidOperationException("camera in use");
-
-        public Task StopAsync()
-        {
-            Stopped = true;
-            return Task.CompletedTask;
-        }
-
-        public void Pump(VideoFrame frame) => FrameAvailable?.Invoke(frame);
-    }
-
     private static CameraManager CreateManager(List<string> started, List<string> stopped)
-        => new(new FakeEnumerator(), id => new FakeFrameSource(id, started, stopped));
+        => new(new FakeEnumerator(), id => new FakeFrameSource(id, started, stopped),
+            null, TimeSpan.Zero);
 
     private sealed class FakeEnumerator : ICameraEnumerator
     {
@@ -93,7 +90,8 @@ public class CameraManagerTests
         FakeFrameSource? captured = null;
         var manager = new CameraManager(
             new FakeEnumerator(),
-            id => captured = new FakeFrameSource(id, started, stopped));
+            id => captured = new FakeFrameSource(id, started, stopped),
+            null, TimeSpan.Zero);
 
         await manager.AcquireAsync("dev1");
         var frame = new VideoFrame(2, 2, new byte[16]);
@@ -105,7 +103,10 @@ public class CameraManagerTests
     [Fact]
     public async Task Acquire_FailingCamera_ReturnsFalseAndStops()
     {
-        var manager = new CameraManager(new FakeEnumerator(), id => new FailingFrameSource(id));
+        var manager = new CameraManager(
+            new FakeEnumerator(),
+            id => new FakeFrameSource(id, new List<string>(), new List<string>(), failOnStart: "camera in use"),
+            null, TimeSpan.Zero);
         string? failedDevice = null;
         manager.CameraFailed += (device, _) => failedDevice = device;
 
@@ -119,4 +120,67 @@ public class CameraManagerTests
         var manager = CreateManager(new List<string>(), new List<string>());
         Assert.False(await manager.AcquireAsync(" "));
     }
+
+    // ─── First-frame proof (the integration test for this change) ───
+
+    [Fact]
+    public async Task Acquire_SilentCamera_NoFirstFrame_FailsAndSurfacesCameraFailed()
+    {
+        var stopped = new List<string>();
+        var manager = new CameraManager(
+            new FakeEnumerator(),
+            id => new FakeFrameSource(id, new List<string>(), stopped),
+            null, TimeSpan.FromMilliseconds(150));
+        string? failedDevice = null;
+        string? failedMessage = null;
+        manager.CameraFailed += (device, message) =>
+        {
+            failedDevice = device;
+            failedMessage = message;
+        };
+
+        // The reader "starts" fine but never delivers a frame — the exact
+        // silent-empty-box scenario. Must fail, be reported, and be rolled back.
+        Assert.False(await manager.AcquireAsync("dev1"));
+        Assert.Equal("dev1", failedDevice);
+        Assert.Contains("no frames", failedMessage);
+        Assert.Null(manager.GetLatestFrame("dev1"));
+        Assert.Contains("dev1", stopped);
+    }
+
+    [Fact]
+    public async Task Acquire_FirstFrameProvesAlive_ReturnsTrueWithoutWaitingTimeout()
+    {
+        var manager = new CameraManager(
+            new FakeEnumerator(),
+            id => new FakeFrameSource(id, new List<string>(), new List<string>(),
+                pumpOnStart: new VideoFrame(2, 2, new byte[16])),
+            null, TimeSpan.FromSeconds(10));
+
+        var started = await manager.AcquireAsync("dev1");
+
+        Assert.True(started);
+        Assert.NotNull(manager.GetLatestFrame("dev1"));
+    }
+
+    [Fact]
+    public async Task Acquire_SourceFailureAfterStart_SurfacesCameraFailedAndRollsBack()
+    {
+        var stopped = new List<string>();
+        FakeFrameSource? source = null;
+        var manager = new CameraManager(
+            new FakeEnumerator(),
+            id => source = new FakeFrameSource(id, new List<string>(), stopped,
+                pumpOnStart: new VideoFrame(2, 2, new byte[16])),
+            null, TimeSpan.Zero);
+        string? failedMessage = null;
+        manager.CameraFailed += (_, message) => failedMessage = message;
+
+        Assert.True(await manager.AcquireAsync("dev1"));
+        source!.Fail("capture failed (0x8007001F): device not available");
+
+        Assert.Contains("device not available", failedMessage);
+        Assert.Null(manager.GetLatestFrame("dev1"));
+        Assert.Contains("dev1", stopped);
+    }
 }