[sampledevicemft] Unable to get MFSampleExtension_CaptureMetadata from pSample

[whenshan]

avstream/sampledevicemft

After we enabled Platform Dmft (as shown below), obtaining MFSampleExtension_CaptureMetadata in CMultipinMft::ProcessInput failed. And this problem will not appear on all computers, but some computers will always have this problem. How do we solve this problem?

[in INF file]
HKR,,EnablePlatformDmft,0x00010001,1

[In sampledevicemft]
In the following code pCaptureMetadata returns NULL.

STDMETHODIMP  CMultipinMft::ProcessInput(...)
{
....
  ComPtr<IMFAttributes> pCaptureMetadata = NULL;
  hr = pSample->GetUnknown(MFSampleExtension_CaptureMetadata, __uuidof(IMFAttributes), &pCaptureMetadata);
...
}

Thank you very much!