c++ - OpenCV - can't get any output from camera -

i trying connect camera opencv, window showing grey output screen no image , output window of vc++ showing following error:

... 'opencv practice.exe': loaded 'c:\windows\syswow64\msyuv.dll', cannot find or open pdb file 'opencv practice.exe': unloaded 'c:\windows\syswow64\msyuv.dll' ...

i tried fining msyuv.dll, , available there.

i have 1 further question, next this, want implement on unity3d, should stick opencv or use emgucv?

#include "stdafx.h" #include <stdio.h> #include <stdlib.h>  #include <opencv\cvaux.h> #include <opencv\highgui.h> #include <opencv\cxcore.h>  using namespace std;  int main(int argc) {     cvcapture* cam = null;`     cvnamedwindow("hi",cv_window_autosize);      iplimage* img = null;     cam = cvcapturefromcam(-1);     char a;     while(1)     {         if(cam != null)         {             img = cvqueryframe(cam);         }         else         {             printf("erro1");             return -1;         }          cvshowimage("hi", img);         = cvwaitkey(20);         if(a == 27)             break;        }      cvreleasecapture(&cam);     cvdestroyallwindows();     return 0; }