// Create the topology.
HRESULT CreateTopology(IMFMediaSource *pSource, IMFActivate *pSinkActivate, IMFTopology **ppTopo)
{
IMFTopology *pTopology = NULL;
IMFPresentationDescriptor *pPD = NULL;
IMFStreamDescriptor *pSD = NULL;
IMFMediaTypeHandler *pHandler = NULL;
IMFTopologyNode *pNode1 = NULL;
IMFTopologyNode *pNode2 = NULL;
HRESULT hr = S_OK;
DWORD cStreams = 0;
CHECK_HR(hr = MFCreateTopology(&pTopology));
CHECK_HR(hr = pSource->CreatePresentationDescriptor(&pPD));
CHECK_HR(hr = pPD->GetStreamDescriptorCount(&cStreams));
for (DWORD i = 0; i < cStreams; i++) {
// In this example, we look for audio streams and connect them to the sink.
BOOL fSelected = FALSE;
GUID majorType;
CHECK_HR(hr = pPD->GetStreamDescriptorByIndex(i, &fSelected, &pSD));
CHECK_HR(hr = pSD->GetMediaTypeHandler(&pHandler));
CHECK_HR(hr = pHandler->GetMajorType(&majorType));
if (majorType == MFMediaType_Video && fSelected) {
CHECK_HR(hr = AddSourceNode(pTopology, pSource, pPD, pSD, &pNode1));
CHECK_HR(hr = AddOutputNode(pTopology, pSinkActivate, 0, &pNode2));
CHECK_HR(hr = pNode1->ConnectOutput(0, pNode2, 0));
break;
} else {
CHECK_HR(hr = pPD->DeselectStream(i));
}
SafeRelease(&pSD);
SafeRelease(&pHandler);
}
*ppTopo = pTopology;
(*ppTopo)->AddRef();
done:
SafeRelease(&pTopology);
SafeRelease(&pNode1);
SafeRelease(&pNode2);
SafeRelease(&pPD);
SafeRelease(&pSD);
SafeRelease(&pHandler);
return hr;
}
