/// <inheritdoc/>
public bool Stop()
{
lock (captureSync) {
if (!Capturing)
{
return(true);
}
if (!VideoCaptureBackend.StopVideoCapture(videoCapture))
{
return(false);
}
rateAnalyzer.Stop();
if (videoFrame != IntPtr.Zero)
{
VideoCaptureBackend.DestroyVideoCaptureFrame(videoCapture, videoFrame);
videoFrame = IntPtr.Zero;
}
if (videoCapture != IntPtr.Zero)
{
VideoCaptureBackend.DestroyVideoCapture(captureContext, videoCapture);
videoFrame = IntPtr.Zero;
}
if (backendSettings != IntPtr.Zero)
{
VideoCaptureBackend.FreeVideoCaptureSettings(backendSettings);
backendSettings = IntPtr.Zero;
}
}
return(true);
}
/// <inheritdoc/>
public SensorDataPacket Process(long timestamp)
{
lock (captureSync) {
if (!Capturing)
{
return(null);
}
long startTime = rateAnalyzer.GetTimeStamp();
// TODO implrement prediction service and divide split multiple calls into grab begin/end
// get image and metadata from the backend
if (!VideoCaptureBackend.BeginVideoCaptureFrameGrab(videoCapture))
{
return(null);
}
if (!VideoCaptureBackend.EndVideoCaptureFrameGrab(videoCapture))
{
return(null);
}
long endTime = rateAnalyzer.GetTimeStamp();
if (endTime - startTime > 0)
{
Console.WriteLine("waited additional " + (endTime - startTime) + "ms for the next frame");
}
rateAnalyzer.Tick();
int width = VideoCaptureBackend.GetVideoCaptureFrameProperty(videoFrame, VideoFrameProperty.Width);
int height = VideoCaptureBackend.GetVideoCaptureFrameProperty(videoFrame, VideoFrameProperty.Height);
RasterImagePixelFormat format = (RasterImagePixelFormat)VideoCaptureBackend.GetVideoCaptureFrameProperty(
videoFrame, VideoFrameProperty.PixelFormat);
int pixelSize = VideoFrame.GetPixelSize(format);
// construct a data packet as result
if (width < 0 || width >= 16384 || height < 0 || height >= 16384 || pixelSize < 1 || pixelSize > 16)
{
return(null);
}
int imageSize = width * height * pixelSize;
byte[] image = new byte[imageSize];
GCHandle imageBuffer = GCHandle.Alloc(image, GCHandleType.Pinned);
if (!VideoCaptureBackend.CopyVideoCaptureFrame(videoFrame, imageBuffer.AddrOfPinnedObject(), imageSize))
{
imageBuffer.Free();
return(null);
}
imageBuffer.Free();
var metadata = new VideoFrameMetadata()
{
FrameRate = rateAnalyzer.AverageFrameRate,
FrameTime = rateAnalyzer.AverageFrameTime,
FrameTimeDeviation = rateAnalyzer.StandardFrameTimeDeviation
};
var frame = new VideoFrame(width, height, format, image, metadata);
// TODO generate packet id
return(new SensorDataPacket(this, SensorDataType.Video, frame, 0));
}
}
static WebcamCapture()
{
// TODO catch exceptions to be safe
captureContext = VideoCaptureBackend.CreateVideoCaptureContext();
}
public bool Start()
{
lock (captureSync) {
if (Capturing)
{
return(true);
}
if (captureContext == IntPtr.Zero)
{
return(false);
}
// create and start the capture process
bool started = false;
do
{
backendSettings = VideoCaptureBackend.AllocVideoCaptureSettings();
if (backendSettings == IntPtr.Zero)
{
break;
}
// TODO apply settings
VideoCaptureBackend.SetVideoCaptureProperty(backendSettings,
VideoCaptureBackend.TranslateSensorProperty(SensorProperty.Exposure), 0);
videoCapture = VideoCaptureBackend.CreateVideoCapture(captureContext, backendSettings);
if (videoCapture == IntPtr.Zero)
{
break;
}
videoFrame = VideoCaptureBackend.CreateVideoCaptureFrame(videoCapture);
if (videoFrame == IntPtr.Zero)
{
break;
}
if (!VideoCaptureBackend.StartVideoCapture(videoCapture, videoFrame))
{
break;
}
rateAnalyzer.Start(1000);
started = true;
} while (false);
// clean up in the correct order if starting was unsuccessful
if (!started)
{
if (videoFrame != IntPtr.Zero)
{
VideoCaptureBackend.DestroyVideoCaptureFrame(videoCapture, videoFrame);
videoFrame = IntPtr.Zero;
}
if (videoCapture != IntPtr.Zero)
{
VideoCaptureBackend.DestroyVideoCapture(captureContext, videoCapture);
videoFrame = IntPtr.Zero;
}
if (backendSettings != IntPtr.Zero)
{
VideoCaptureBackend.FreeVideoCaptureSettings(backendSettings);
backendSettings = IntPtr.Zero;
}
return(false);
}
// finally retrieve updated settings from the backend
if (VideoCaptureBackend.GetVideoCaptureSettings(videoCapture, backendSettings))
{
// TODO update local settings
int width = VideoCaptureBackend.GetVideoCaptureProperty(backendSettings, VideoCaptureProperty.FrameWidth);
int height = VideoCaptureBackend.GetVideoCaptureProperty(backendSettings, VideoCaptureProperty.FrameHeight);
int rate = VideoCaptureBackend.GetVideoCaptureProperty(backendSettings, VideoCaptureProperty.FrameRate);
int bright = VideoCaptureBackend.GetVideoCaptureProperty(backendSettings, VideoCaptureProperty.Brightness);
int gain = VideoCaptureBackend.GetVideoCaptureProperty(backendSettings, VideoCaptureProperty.Gain);
int exposure = VideoCaptureBackend.GetVideoCaptureProperty(backendSettings, VideoCaptureProperty.Exposure);
if (width <= 0)
{
settings.SetAuto(SensorProperty.FrameWidth);
}
else
{
settings.SetInteger(SensorProperty.FrameWidth, width);
}
if (height <= 0)
{
settings.SetAuto(SensorProperty.FrameHeight);
}
else
{
settings.SetInteger(SensorProperty.FrameHeight, height);
}
if (rate <= 0)
{
settings.SetAuto(SensorProperty.FrameRate);
}
else
{
settings.SetInteger(SensorProperty.FrameRate, rate);
}
if (bright < 0)
{
settings.SetAuto(SensorProperty.Brightness);
}
else
{
settings.SetInteger(SensorProperty.Brightness, bright);
}
if (gain < 0)
{
settings.SetAuto(SensorProperty.Gain);
}
else
{
settings.SetInteger(SensorProperty.Gain, gain);
}
if (exposure < 0)
{
settings.SetAuto(SensorProperty.Exposure);
}
else
{
settings.SetInteger(SensorProperty.Exposure, exposure);
}
}
}
return(true);
}
