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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)

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This commit is contained in:
Llama Chile Shop
2026-08-12 07:11:54 -07:00
parent cc3b1c9234
commit 60259c08c2
2 changed files with 235 additions and 63 deletions
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Services/MediaCaptureFrameSource.cs
+148 -40
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@@ -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();
MediaFrameReader? reader = null;
try
// Fallback ladder: prefer the camera's VideoPreview stream, but if the
// reader refuses to start there (NoVideoFrameAvailable), retry against
// 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
{
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());
if (!await TryStartAsync(preferVideoRecord: true))
throw new InvalidOperationException(
$"Camera '{_deviceId}' exposes no video source (found: {kinds}). " +
"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;
_lastError ?? $"Camera '{_deviceId}' could not be started.");
}
}
@@ -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)