static void DecompressionCallback (IntPtr outputCallbackClosure, IntPtr sourceFrame, VTStatus status,
VTDecodeInfoFlags infoFlags, IntPtr imageBufferPtr, CMTime presentationTimeStamp, CMTime presentationDuration)
{
var gch = GCHandle.FromIntPtr (outputCallbackClosure);
var func = (VTDecompressionOutputCallback) gch.Target;
// Apple headers states that the callback should get a CVImageBuffer but it turned out that not all of them are a
// CVImageBuffer, some can be instances of CVImageBuffer and others can be instances of CVPixelBuffer. So we go one
// step further in the inheritance hierarchy and supply the callback a CVPixelBuffer and the callback supplies
// to the developer a CVImageBuffer, so the developer can choose when to use one or the other and we mimic
// what Apple provides on its headers.
using (var sampleBuffer = new CVPixelBuffer (imageBufferPtr)) {
func (sourceFrame, status, infoFlags, sampleBuffer, presentationTimeStamp, presentationDuration);
}
}
public VTStatus CopyBlackPixelBuffer (out CVPixelBuffer pixelBuffer)
{
if (Handle == IntPtr.Zero)
throw new ObjectDisposedException ("DecompressionSession");
IntPtr ret;
var result = VTDecompressionSessionCopyBlackPixelBuffer (Handle, out ret);
pixelBuffer = Runtime.GetINativeObject<CVPixelBuffer> (ret, true);
CFObject.CFRelease (ret);
return result;
}
