directshow怎么枚举摄像头支持的所有分辨率和帧速

HRESULT SetResolution()

{

//	MYLOG("SetResolution");

	HRESULT hr = S_OK;

	CComPtr<IAMStreamConfig>		pConfig;

	

	CComPtr<IPin> previewPin = GetPinByName(pVideoCapture, TEXT("preview"));



	if (previewPin == NULL) 

	{

		MYLOG("fail to find the preview pin");

		

		previewPin = GetPinByName(pVideoCapture, TEXT("capture"));

		if (previewPin == NULL)

		{

			// no preview or still, fail here

			return E_FAIL;

		}

	}	



	hr = previewPin->QueryInterface(&pConfig);

	int iCount, iSize;

	VIDEO_STREAM_CONFIG_CAPS caps;

	pConfig->GetNumberOfCapabilities(&iCount, &iSize);

	if (iCount == 0)

	{

		MYLOG("fail to GetNumberOfCapabilities");

		return E_FAIL;

	}	



	CameraCapacity* paCapacity = new CameraCapacity[iCount];

	// find and save all the capacities

	AM_MEDIA_TYPE *pmtPV=NULL;

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

	{

		hr=pConfig->GetStreamCaps(i, &pmtPV, (BYTE*)&caps);

		if (hr != S_OK)

		{

			MYLOG("fail to get stream caps");

		}

		else

		{

			if (pmtPV->subtype == MEDIASUBTYPE_YV12 ||

				pmtPV->subtype == MEDIASUBTYPE_RGB565 ||

				pmtPV->subtype == MEDIASUBTYPE_UYVY )

			{

				paCapacity[i].index  = i;

				paCapacity[i].width  = caps.MaxOutputSize.cx;

				paCapacity[i].height = caps.MaxOutputSize.cy;

				paCapacity[i].guid = pmtPV->subtype;

				MYLOG( "index = %d, width = %d, height = %d", paCapacity[i].index, paCapacity[i].width, paCapacity[i].height);

				

				// to correct the value;

				if (paCapacity[i].width < 0)

					paCapacity[i].width *= -1;

				if (paCapacity[i].height < 0)

					paCapacity[i].height *= -1;

			}

			DeleteMediaType(pmtPV);	

		}

	}

	

	// here, we need find the most suitable size.

	int suitableIndex = findSuitableResolution(paCapacity,iCount) ;	

		

	g_suitableResolution = paCapacity[suitableIndex];

	if (IsEqualGUID (g_suitableResolution.guid,MEDIASUBTYPE_RGB565))

	{

		g_bVerticalFlip = true;

	}



	hr=pConfig->GetStreamCaps(paCapacity[suitableIndex].index, &pmtPV, (BYTE*)&caps);

	delete [] paCapacity;

	if(hr== S_OK)

	{

		hr=pConfig->SetFormat(pmtPV);

		DeleteMediaType(pmtPV);	

	}

	else 

	{

		MYLOG("Fail to set format");

	}

	previewPin.Release();

	previewPin = NULL;

	return hr;

}