跪求用USB摄像头获取并保存图像的c或c++代码

class CSampleGrabberCB : public ISampleGrabberCB 

{

public:

	STDMETHODIMP_(ULONG) AddRef() { return 2; }

    STDMETHODIMP_(ULONG) Release() { return 1; }

	STDMETHODIMP QueryInterface(REFIID riid, void ** ppv)

    {

        if( riid == IID_ISampleGrabberCB || riid == IID_IUnknown ) 

        {

            *ppv = (void *) static_cast<ISampleGrabberCB*> ( this );

            return NOERROR;

        }    

        return E_NOINTERFACE;

    }

	STDMETHODIMP SampleCB( double SampleTime, IMediaSample * pSample )

    {

        return 0;

    }

	 STDMETHODIMP BufferCB( double dblSampleTime, BYTE * pBuffer, long lBufferSize )

    {



		 //g_dateLen=lBufferSize;

        /*date = new BYTE[lBufferSize];*/

		memcpy(g_capDate, pBuffer, lBufferSize);

		//std::cout<<lBufferSize<<" ";

        return 0;

    }



};