public async Task StartStreamAsync(bool isForRealTimeProcessing = false)
{
try
{
if (captureManager == null ||
captureManager.CameraStreamState == CameraStreamState.Shutdown ||
captureManager.CameraStreamState == CameraStreamState.NotStreaming)
{
if (captureManager != null)
{
captureManager.Dispose();
}
captureManager = new MediaCapture();
MediaCaptureInitializationSettings settings = new MediaCaptureInitializationSettings();
var allCameras = await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture);
await captureManager.InitializeAsync(settings);
await SetVideoEncodingToHighestResolution(isForRealTimeProcessing);
this.webCamCaptureElement.Source = captureManager;
}
if (captureManager.CameraStreamState == CameraStreamState.NotStreaming)
{
if (this.faceTracker == null)
{
this.faceTracker = await FaceTracker.CreateAsync();
}
this.videoProperties = this.captureManager.VideoDeviceController.GetMediaStreamProperties(MediaStreamType.VideoPreview) as VideoEncodingProperties;
await captureManager.StartPreviewAsync();
if (this.frameProcessingTimer != null)
{
this.frameProcessingTimer.Cancel();
frameProcessingSemaphore.Release();
}
TimeSpan timerInterval = TimeSpan.FromMilliseconds(66); //15fps
this.frameProcessingTimer = ThreadPoolTimer.CreatePeriodicTimer(new TimerElapsedHandler(ProcessCurrentVideoFrame), timerInterval);
this.cameraControlSymbol.Symbol = Symbol.Camera;
this.webCamCaptureElement.Visibility = Visibility.Visible;
}
}
catch (Exception ex)
{
await CoreUtil.GenericApiCallExceptionHandler(ex, "Lỗi khởi động camera.");
}
}
private async void OnDataContextChanged(FrameworkElement sender, DataContextChangedEventArgs args)
{
ImageAnalyzer dataContext = this.DataContext as ImageAnalyzer;
if (this.currentImage != dataContext)
{
this.currentImage = dataContext;
}
else
{
// Windows sometimes fires multiple DataContextChanged events.
// If we are here that is one of those cases, and since we already set
// the data context to this value we can ignore it
return;
}
foreach (var child in this.hostGrid.Children.Where(c => !(c is Image)).ToArray())
{
this.hostGrid.Children.Remove(child);
}
// remove the current source
this.bitmapImage.UriSource = null;
if (dataContext != null)
{
try
{
if (dataContext.ImageUrl != null)
{
this.bitmapImage.UriSource = new Uri(dataContext.ImageUrl);
}
else if (dataContext.GetImageStreamCallback != null)
{
await this.bitmapImage.SetSourceAsync((await dataContext.GetImageStreamCallback()).AsRandomAccessStream());
}
}
catch (Exception ex)
{
// If we fail to load the image we will just not display it
this.bitmapImage.UriSource = null;
if (this.ShowDialogOnApiErrors)
{
await CoreUtil.GenericApiCallExceptionHandler(ex, "Error loading captured image.");
}
}
}
}
public async Task ProcessingStreamAsync()
{
try
{
while (isProcessingLoopInProgress)
{
await ProcessCurrentVideoFrame();
await Task.Delay(TimeDelay);
}
}
catch (Exception ex)
{
await CoreUtil.GenericApiCallExceptionHandler(ex, "Lỗi khởi động camera.");
}
}
