/// <summary> Stops capturing and processing video frames. </summary>
/// <returns> A Task. </returns>
public async Task StopProcessingAsync()
{
Logger.LogInformation("Stopping capturing tasks");
foreach (VideoStreamGrabber vs in _streams)
{
await vs.StopProcessingAsync().ConfigureAwait(false);
vs.Dispose();
}
_streams.Clear();
Logger.LogInformation("Stopping merger");
if (_merger != null)
{
await _merger.StopProcessingAsync().ConfigureAwait(false);
_merger.Dispose();
_merger = null;
}
Logger.LogInformation("Stopping analyzer");
if (_analyzer != null)
{
await _analyzer.StopProcessingAsync().ConfigureAwait(false);
_analyzer.Dispose();
_analyzer = null;
}
Logger.LogInformation("Stopping result publisher");
if (_resultPublisher != null)
{
await _resultPublisher.StopProcessingAsync(default).ConfigureAwait(false);
public async Task StartProcessingAll(CancellationToken cancellationToken)
{
Logger.LogInformation("Create processing pipeline");
CreateCapturingChannels();
var analysisChannel = CreateMultiFrameChannel();
var outputChannel = CreateOutputChannel();
var inputReaders = _capturingChannels.Select(c => c.Reader).ToList();
_merger = new SyncedMultiChannelMerger <VideoFrame>(
inputReaders, analysisChannel.Writer, Logger);
var mergerTask = _merger.ExecuteProcessingAsync(cancellationToken);
_analyzer = new DnnDetectorChannelTransformer(_detector,
_detectionOptions.DetectionThreshold,
analysisChannel.Reader, outputChannel.Writer, _healthCheck, Logger);
var analyzerTask = _analyzer.ExecuteProcessingAsync(cancellationToken);
_resultPublisher = new AnalyzedVideoFrameChannelConsumer(
outputChannel.Reader, _resultProcessors,
_detectionOptions.ObjectWhiteList,
Logger);
var resultPublisherTask = _resultPublisher.ExecuteProcessingAsync(cancellationToken);
Logger.LogInformation("Start processing pipeline");
await StartCapturingAllStreamsAsync(cancellationToken).ConfigureAwait(false);
//Only start the trigger when we know that all capturing streams have started.
_trigger = new PeriodicTrigger(Logger, _streams);
_trigger.Start(TimeSpan.FromSeconds(_streams.Count), _analysisInterval);
await Task.WhenAll(mergerTask, analyzerTask, resultPublisherTask).ConfigureAwait(false);
}