如何设置ISampleGrabber::SetCallback来抓取BMP图片（dshow小问题）

[King_Dragon]

现有一任务是要实时的抓取视频捕捉卡的图片信息，对图片信息进行分析和采样。程序在图片抓取的地方卡壳了，偶不知道怎样设置ISampleGrabber::SetCallback来进行图片的抓取，希望能给出完整的例子或者是完整的说明（偶对dshow不熟悉）

[autoegg]

我当时也有这个问题，后来用IMediaDet接口的WriteBitmapBits函数就可以了，很方便的。
具体见SDK吧。：）

[Bruce5260]

class CSampleGrabberCB : public ISampleGrabberCB
{
public:
// these will get set by the main thread below. We need to
// know this in order to write out the bmp
long lWidth;
long lHeight;

CCaptureToBitmap * pOwner;//这里是怎样解析的
//因为这里.h文件包括近来了
char m_szCapDir[MAX_PATH]; // the directory we want to capture to
char m_szSnappedName[MAX_PATH];
BOOL bFileWritten;

CSampleGrabberCB( )
{
pOwner = NULL;
m_szCapDir[0] = 0;
bFileWritten = FALSE;


}

// fake out any COM ref counting
//
STDMETHODIMP_(ULONG) AddRef() { return 2; }
STDMETHODIMP_(ULONG) Release() { return 1; }

// fake out any COM QI'ing
//
STDMETHODIMP QueryInterface(REFIID riid, void ** ppv)
{
if( riid == IID_ISampleGrabberCB || riid == IID_IUnknown )
{
*ppv = (void *) static_cast<ISampleGrabberCB*> ( this );
return NOERROR;
}
return E_NOINTERFACE;
}

// we don't implement this interface for this example
//
STDMETHODIMP SampleCB( double SampleTime, IMediaSample * pSample )
{
return 0;
}

STDMETHODIMP BufferCB( double dblSampleTime, BYTE * pBuffer, long lBufferSize );
// This is the implementation function that writes the captured video
// data onto a bitmap on the user's disk.
//
BOOL CopyBitmap( double dblSampleTime, BYTE * pBuffer, long lBufferSize );


};

//-----------------------
/////////////////////////////////////////////////////////////////////////////

//{{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_CAPTURETOBITMAP_H__2A36988C_9FFD_43CA_AB55_CBEB1E2CDCD7__INCLUDED_)
////////////////////////////////////

m_pGrabber->SetCallback( &mCB, 1 );
//调用ISampleGrabber::BufferCB