When receiving an output from IMFTransform::ProcessOutput, calling GetUINT32(MFSampleExtension_CleanPoint) on the sample fails and returns MF_E_ATTRIBUTENOTFOUND only while using the AMDh264Encoder (NV12 in, H264 out), as such there are no keyframes in the final output video so it is corrupted.
What causes getting attribute MFSampleExtension_CleanPoint MF_E_ATTRIBUTENOTFOUND to fail, only on the AMDh264Encoder?