How to set media format in IMFMediaSource

Question

I'm, trying to implement a grabber using IMFMediaSource, IMFMediaSession and IMFTopology. I built a topology including the IMFMediaSource and an IMFSampleGrabberSinkCallback. My problem is how to set the current media format. I found a function in msdn:
HRESULT cMFDevice::setDeviceFormat(IMFMediaType *i_type)
IMFPresentationDescriptor *presentationDescriptor = nullptr;
HRESULT hr = m_mediaSource->CreatePresentationDescriptor(&presentationDescriptor);
if (SUCCEEDED(hr))
BOOL selected = FALSE;
IMFStreamDescriptor *streamDescriptor = nullptr;
hr = presentationDescriptor->GetStreamDescriptorByIndex(0, &selected, &streamDescriptor);
if (SUCCEEDED(hr))
IMFMediaTypeHandler *handler = nullptr;
hr = streamDescriptor->GetMediaTypeHandler(&handler);
if (SUCCEEDED(hr))
hr = handler->SetCurrentMediaType(i_type);
SafeRelease(&handler);
SafeRelease(&streamDescriptor);
SafeRelease(&presentationDescriptor);
return hr;
That function works. But only once. If I start the session and stopped it, the current format does change. All return values are fine, but format does not changes in OnProcessSample callback. Any ideas? Do I have to rebuilt complete topology? Must I stop
the session?

Answer 1

See Chapter 6 of the Pages User Guide PDF. You can download it from the Help menu.
Once you have mastered Styles, you should be on top of this problem. You may have some specific questions on formatting along the way, and there are lots of experts here to help you.
Jerry