protected ProcessingSession(IntPtr handle)
        {
            _handle = handle;

            _cb_progress = new CAPI.ProgressCallback(ProgressCallback);
            CAPI.RegisterProgressCallback(_handle, _cb_progress, 0x0F);
        }
 public void Dispose()
 {
     if (_handle != IntPtr.Zero)
     {
         var h = _handle;
         _handle = IntPtr.Zero;
         CAPI.CloseVideo(h);
         _cb_progress = null;
     }
 }