c# VideoWriter保存的视频不支持中文路径

string _fileName = _baseDirectory+DateTime.Now.ToString("MMddyyyyHmmss")+".AVI";

byte[] byteArray = System.Text.Encoding.UTF8.GetBytes(_fileName);
_fileName = System.Text.Encoding.Default.GetString(byteArray);

VideoWriter vw = new VideoWriter(_fileName, CvInvoke.CV_FOURCC(‘M‘, ‘P‘, ‘4‘, ‘2‘), 30, 640, 480, true);