IAudioStateMonitor::GetSoundLevel method

AudioStateMonitorSoundLevel GetSoundLevel();

// global variables 
winrt::com_ptr<IAudioStateMonitor> g_audioStateMonitor; 
AudioStateMonitorRegistrationHandle g_registration = 0; 

// Returns true if the GameMedia stream should be disabled, false if it should be 
// enabled. 
bool IsSoundLevelMuted(_In_ IAudioStateMonitor* audioStateMonitor) 
{ 
    return (audioStateMonitor->GetSoundLevel() == AudioStateMonitorSoundLevel::Muted); 
} 

HRESULT StartTrackingSoundLevel() 
{ 
    // Create an AudioStateMonitor and register for callbacks from it. 
    HRESULT hr = RegisterForSoundLevelChanges(); 
    if (SUCCEEDED(hr)) 
    { 
        // Check the current sound level and determine if the GameMedia stream should 
        // be enabled. 
        bool disableGameMediaStream = IsSoundLevelMuted(g_audioStateMonitor.get()); 

        // Add code here that enables or disables the GameMedia stream based on the 
        // value of the boolean. 
    } 
    return hr; 
} 

HRESULT RegisterForSoundLevelChanges() 
{ 
    HRESULT hr = S_OK; 

    // Create a new AudioStateMonitor for the GameMedia category, if needed, and 
    // register for callbacks. 
    if (m_audioStateMonitor == nullptr) 
    { 
        hr = CreateRenderAudioStateMonitorForCategoryAndDeviceRole( 
            AudioCategory_GameMedia, ERole::eConsole, g_audioStateMonitor.put()); 
        if (SUCCEEDED(hr)) 
        { 
            // Optional "context" parameter is not used in this example, 
            // and is set to nullptr. 
            hr = g_audioStateMonitor->RegisterCallback(OnAudioStateMonitorCallback, nullptr, &g_registration); 
        } 
    } 

    if (FAILED(hr)) 
    { 
        // g_audioStateMonitor is a smart pointer, so if an IAudioStateMonitor was 
        // allocated, setting the smart pointer to null invokes the Release method 
        // which will decrement its usage count and ensure that the object is properly 
        // destroyed. 
        g_audioStateMonitor = nullptr; 
    } 
    return hr; 
} 

// Unregister callbacks on program shutdown 
void UnregisterForSoundLevelChanges() 
{ 
    if (g_audioStateMonitor != nullptr) 
    { 
        if (g_registration) 
        { 
            g_audioStateMonitor->UnregisterCallback(g_registration); 
        } 

        // g_audioStateMonitor is a smart pointer, so setting it to null 
        // invokes the Release method to decrement its usage count. 
        g_audioStateMonitor = nullptr; 
    } 
} 

void OnAudioStateMonitorCallback(_In_ IAudioStateMonitor* audioStateMonitor, _In_opt_ void* context) 
{ 
    bool disableGameMediaStream = IsSoundLevelMuted(audioStateMonitor); 

    // Add code here that enables or disables the GameMedia stream based on the value 
    // of the boolean. 
}