internal void AddFrame(WriteableBitmap bitmap)
{
INSSBuffer sampleBuffer = null;
if (BitmapBounds.Width != bitmap.Width)
{
Guid mediaSubType;
short bitCount;
BitmapBounds = new Rectangle(0, 0, (int)bitmap.Width, (int)bitmap.Height);
GetMediaType(bitmap.Format, out mediaSubType, out bitCount);
ConfigureMediaWriter(BitmapBounds.Width, BitmapBounds.Height, mediaSubType, bitCount);
MediaWriterConfigured = true;
if (!MediaWriterIsWriting)
{
MediaWriter.BeginWriting();
MediaWriterIsWriting = true;
}
}
try
{
// Compute size of bitmap in bytes. Strides may be negative.
int bitmapSize = Math.Abs(bitmap.BackBufferStride * (int)bitmap.Height);
IntPtr framePointer;
// Get a sample interface
MediaWriter.AllocateSample(bitmapSize, out sampleBuffer);
// Get the buffer from the sample interface. This is
// where we copy the bitmap data to
sampleBuffer.GetBuffer(out framePointer);
// Copy the bitmap data into the sample buffer
CopyFrame(bitmap.BackBuffer, framePointer, bitmapSize);
// Write the sample to the output - Sometimes, for reasons I can't explain,
// writing a sample fails. However, writing the same sample again
// works. Go figure.
int iRetry = 0;
do
{
try
{
MediaWriter.WriteSample(VideoChannelIndex, 10000 * CurrentSampleTimeStamp, SampleFlag.CleanPoint, sampleBuffer);
break;
}
catch (COMException e)
{
if ((iRetry++ < 3) && (e.ErrorCode != NSResults.E_INVALID_DATA))
{
continue;
}
else
{
throw;
}
}
} while (true);
// update the time based on the framerate
CurrentSampleTimeStamp = (++CurrentSampleIndex * 1000) / Constants.VideoFrameRate;
}
finally
{
// Release the locals
if (sampleBuffer != null)
{
Marshal.ReleaseComObject(sampleBuffer);
sampleBuffer = null;
}
}
}
