HRESULT UseCaptureVideoDeviceAudio(IltmmCapture *pCapture) { HRESULT hr; VARIANT_BOOL vEnable; // try to video device audio enabled state pCapture->get_UseVideoDeviceAudio(&vEnable); if (FAILED(hr)) return hr; // if we are not using video device audio if (vEnable == VARIANT_FALSE) { // try to enable it pCapture->put_UseVideoDeviceAudio(VARIANT_TRUE); if (FAILED(hr)) return hr; } return S_OK; }