获取精确毫秒的时间间隔

//开始
 LARGE_INTEGER iLarge;
 QueryPerformanceFrequency(&iLarge); 
 double dbFreq = (double) iLarge.QuadPart;
 QueryPerformanceCounter(&iLarge);
 double dbBegin = (double) iLarge.QuadPart;
//结束部分
QueryPerformanceCounter(&iLarge);
 double dbEnd = (double) iLarge.QuadPart;
 int ms = (int) ((dbEnd - dbBegin) * 1000.0 / dbFreq); 
 CString str;str.Format(L"/nDecoding time =%d",ms);
SetWindowText(str);