/// <summary>
/// Initializes a new instance of the <see cref="AsyncRealtimeVideoReader"/> class.
/// </summary>
/// <param name="captureDevice">The capture device.</param>
/// <param name="immediateStart">True to start video reading immediately.</param>
public AsyncRealtimeVideoReader(CaptureDeviceInfo captureDevice, bool immediateStart = true)
: base(captureDevice)
{
// Start immediately if requested
m_currentBufferLock = new object();
m_currentBuffer = null;
m_currentBufferTimestamp = DateTime.MinValue;
if (immediateStart)
{
this.Start();
}
}
/// <summary>
/// Initializes a new instance of the <see cref="AsyncRealtimeVideoReader"/> class.
/// </summary>
/// <param name="videoSource">The source of the video file.</param>
/// <param name="immediateStart">True to start video reading immediately.</param>
public AsyncRealtimeVideoReader(ResourceLink videoSource, bool immediateStart = true)
: base(videoSource)
{
// Start immediately if requested
m_currentBufferLock = new object();
m_currentBuffer = null;
m_currentBufferTimestamp = DateTime.MinValue;
if (immediateStart)
{
this.Start();
}
}
/// <summary>
/// Performs asynchronous video reading.
/// </summary>
/// <param name="cancelToken">The cancel token.</param>
private async Task PerformVideoReadingAsync(CancellationToken cancelToken)
{
// Ensure that we are working on the ThreadPool
// => Thread.CurrentThread.IsThreadPoolThread not possible on WinRT platform
await Task.Delay(100).ConfigureAwait(false);
bool doContinue = true;
bool endReached = false;
while (doContinue && (!cancelToken.IsCancellationRequested) && (!this.IsDisposed))
{
bool currentBufferChanged = false;
// Read next frame
SeeingSharpMediaBuffer mediaBuffer = this.ReadFrameInternal();
if (mediaBuffer != null)
{
lock (m_currentBufferLock)
{
GraphicsHelper.SafeDispose(ref m_currentBuffer);
m_currentBuffer = mediaBuffer;
m_currentBufferTimestamp = DateTime.UtcNow;
m_processedFrameCount++;
currentBufferChanged = true;
endReached = false;
}
}
// Fire VideoReachedEnd event
if (base.EndReached && (!endReached))
{
endReached = true;
try { VideoReachedEnd.Raise(this, EventArgs.Empty); }
catch
{
// TODO: Raise an alert or something here
}
}
// Wait some time because we could no read the last frame
if (!currentBufferChanged)
{
await Task.Delay(200);
}
}
}
/// <summary>
/// Reads the next frame and puts it into the provided buffer.
/// </summary>
/// <param name="targetBuffer">The target buffer to write to.</param>
public bool ReadFrame(MemoryMappedTexture32bpp targetBuffer)
{
this.EnsureNotNullOrDisposed("this");
targetBuffer.EnsureNotNull(nameof(targetBuffer));
if ((targetBuffer.Width != base.FrameSize.Width) ||
(targetBuffer.Height != base.FrameSize.Height))
{
throw new SeeingSharpGraphicsException("Size of the given buffer does not match the video size!");
}
// Read the frame
SeeingSharpMediaBuffer mediaSharpManaged = base.ReadFrameInternal();
if (mediaSharpManaged == null)
{
return(false);
}
// Process the frame
try
{
MF.MediaBuffer mediaBuffer = mediaSharpManaged.GetBuffer();
int cbMaxLength;
int cbCurrentLenght;
IntPtr mediaBufferPointer = mediaBuffer.Lock(out cbMaxLength, out cbCurrentLenght);
// Performance optimization using CopyMemory method
// see http://www.rolandk.de/wp/2015/05/wie-schnell-man-speicher-falsch-kopieren-kann/
CommonTools.CopyMemory(
mediaBufferPointer, targetBuffer.Pointer,
(ulong)(base.FrameSize.Width * base.FrameSize.Height * 4));
return(true);
}
finally
{
mediaSharpManaged.Dispose();
}
}
