char* CCameraDS::QueryFrame()

{

	long evCode, size = 0;

#if CALLBACKMODE

	static double lastSampleTime=0;

	if( lastSampleTime == cbInfo.dblSampleTime)

		return NULL;

	if(cbInfo.lBufferSize == 0)

		return NULL;

	if ( m_nBufferSize != cbInfo.lBufferSize)

	{

		if (m_pFrame)

		{

			free(m_pFrame);

		}

		m_nBufferSize = cbInfo.lBufferSize;

		m_pFrame = (char*)malloc(m_nBufferSize);//cvCreateImage(cvSize(m_nWidth, m_nHeight), IPL_DEPTH_8U, 3);

	}

	lastSampleTime = cbInfo.dblSampleTime;

	m_pFrame2 = (char*)cbInfo.pBuffer;

#else

	m_pMediaControl->Run();

	m_pMediaEvent->WaitForCompletion(INFINITE, &evCode);

	m_pSampleGrabber->GetCurrentBuffer(&size, NULL);

	if(size == 0)

		return NULL;

	//if the buffer size changed

	if (size != m_nBufferSize)

	{

		if (m_pFrame)

		{

			free(m_pFrame);

		}

		if (m_pFrame2)

		{

			free(m_pFrame2);

		}

		m_nBufferSize = size;

		m_pFrame = (char*)malloc(m_nWidth*m_nHeight*3);//cvCreateImage(cvSize(m_nWidth, m_nHeight), IPL_DEPTH_8U, 3);

		m_pFrame2 = (char*)malloc(m_nWidth*m_nHeight*3);

	}

	m_pSampleGrabber->GetCurrentBuffer(&m_nBufferSize, (long*)m_pFrame2);

	//cvFlip(m_pFrame);

#endif

	for(int i=0;i<m_nHeight;i++)

		memcpy(m_pFrame+m_nWidth*3*i,m_pFrame2+m_nWidth*3*(m_nHeight-1-i),m_nWidth*3);

	return m_pFrame;

}