C / C++ / MFC

CComPtr<IPin> findPin(CComPtr<IBaseFilter>& pFilter, PIN_DIRECTION dir)
{
    PIN_DIRECTION pinDir;  // Direction of the current pin
    CComPtr<IEnumPins> pPinEnum;
    pFilter->EnumPins(&pPinEnum); // Get an enumeration of the filters pins
    while(1)
    {
        CComPtr<IPin> pPin; // Destroy at end of loop iteration
        if( pPinEnum->Next(1,&pPin,0) == S_OK )	// If enumeration works
        {
            pPin->QueryDirection(&pinDir);
            if(pinDir == dir) // If the pin direction matches
            {
                return pPin;
            }
        }
        else
        {
            return CComPtr<IPin>(); // Wraps a return of null (see default c'tor)
        }
    }
}
void setFormat(int width, int height, const GUID& subtype)
{
    int size;
    int count;
    VIDEO_STREAM_CONFIG_CAPS vscc;
    
    CComPtr<IPin> pPin = findPin(pSrc_,PINDIR_OUTPUT);
    CComQIPtr<IAMStreamConfig> pConfig(pPin);

    pConfig->GetNumberOfCapabilities(&count, &size);
    for(int i = 0; i < count; i++)
    {
        AM_MEDIA_TYPE *pMt;
        pConfig->GetStreamCaps(i, &pMt, (BYTE*)&vscc);
        if( (vscc.InputSize.cx == width) &&
            (vscc.InputSize.cy == height) &&
            (pMt->subtype == subtype) )
        {
            pConfig->SetFormat(pMt);
            DeleteMediaType(pMt);
            return;
        }
        DeleteMediaType(pMt);
    }
}