vc 从视频中抓图的程序

CFileDialog   dlg(TRUE); 
if(dlg.DoModal()==IDCANCEL)  //
return; 

CString path;
path=dlg.GetPathName();
BSTR bstr=path.AllocSysString();

IGraphBuilder *pGraphBuilder;
IMediaControl *pMediaControl;
IBasicVideo *pBasicVideo;
CoInitialize(NULL);
CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC, IID_IGraphBuilder, (LPVOID *)&pGraphBuilder);
pGraphBuilder->QueryInterface(IID_IMediaControl,(LPVOID *)&pMediaControl);
pMediaControl->RenderFile(bstr);//(FILENAME);

pGraphBuilder->QueryInterface(IID_IBasicVideo, (LPVOID *)&pBasicVideo);

pMediaControl->Run();
// The image will be saved when OK is clicked
MessageBox("Grab Image",NULL,MB_OK);

// Must Pause before using GetCurrentImage
pMediaControl->Pause();
// get width and height
long height, width;
pBasicVideo->get_VideoHeight(&height);
pBasicVideo->get_VideoWidth(&width);
long bufSize;
long *imgData;