Adjust volume / mute from my Qt C++ programm

Question

Under Windows (7,8) I can mute / adjust volume as per application and per output device.

I wonder how I can set / query these values from my C++ Qt application. Basically I need to figure out / accomplish (use cases):

1. Is the global mute set (per device)? Set global mute from my application.
2. Is the application's mixer mute set? Set mixer mute.
3. Set mixer volume, set global volume.
4. Query mixer volume, set mixer volume?

Wherever possible I am looking for the Qt-ish way to accomplish things, keeping code as platform independent as possible. I can imagine to query the global mute via an OS-independent API, but using a Windows only class for the mixer.

From the C# question Get Master Sound Volume in c# I understand IAudioMeterInformation, IMMDeviceCollection, IMMDevice are the MSDN documentation entry points for Windows specific handling.

How do I tell if the master volume is muted? shows how commands can be send via WM_APPCOMMAND . Again, windows specific, also not allowing to query values but only to set them.

Is there something for Qt encapsulating these things? Is it Phonon I need to use? Checking Phonon briefly I did not see any methods for what I need, but I might have missed it.