How to properly shutdown media session when micophone is unplugged ?

I modified the transcode sample to record microphone to wmv file. The record stopped when I unplugged the mic.

However, the recorded file show that the length of the media is 0:00:00 (file size looks alright though).

This is due to  hr = pEvent->GetStatus(&hrStatus); giving hrStatus of 0xc00d4e86, causing the session to auto-terminate.

Thus the output file did not close and finalise properly. Is there a way to solve this ?

HRESULT CTranscoder::Transcode()
{
    assert (m_pSession);
    IMFMediaEvent* pEvent = NULL;
    MediaEventType meType = MEUnknown;  // Event type

    HRESULT hr = S_OK;
    HRESULT hrStatus = S_OK;            // Event status

    //Get media session events synchronously
    while (meType != MESessionClosed)
    {
        hr = m_pSession->GetEvent(0, &pEvent);

        if (FAILED(hr)) { break; }

        // Get the event type.
        hr = pEvent->GetType(&meType);
        if (FAILED(hr)) { break; }

        hr = pEvent->GetStatus(&hrStatus);
        if (FAILED(hr)) { break; }

        if (FAILED(hrStatus))
        {
            wprintf_s(L"Failed. 0x%X error condition triggered this event.\n", hrStatus);
            hr = hrStatus;
            break;
        }

        switch (meType)
        {
        case MESessionTopologySet:
            hr = Start();
            if (SUCCEEDED(hr))
            {
                wprintf_s(L"Ready to start.\n");
            }
            break;

        case MESessionStarted:
            wprintf_s(L"Started encoding...\n");
            break;

        case MESessionEnded:
            hr = m_pSession->Close();
            if (SUCCEEDED(hr))
            {
                wprintf_s(L"Finished encoding.\n");
            }
            break;

        case MESessionClosed:
            wprintf_s(L"Output file created.\n");
            break;
        }

        if (FAILED(hr))
        {
            break;
        }

        SafeRelease(&pEvent);
    }

    SafeRelease(&pEvent);
    return hr;
}