XAudio2 is a lower-level audio API for Microsoft Windows. It can work on almost all windows platforms, from xp to win10, and windows phone, xbox. Windows phone, win8 and later natively support XAudio2. It will be used as the default audio renderer. To work on windows <= 7, you have to install XAudio2 driver from DirectX SDK, you can download here http://sourceforge.net/projects/qtav/files/depends/DXSDK2010_XAudio2_redist.7z/download
Now you can build QtAV without OpenAL. QtAV supports to build XAudio2 with any mingw/msvc toolchain for both XAudio<=2.7 (old API, used in win7 and older) and XAudio>=2.8. QtAV can detect the highest XAudio2 runtime support at runtime and use it if possible.
The implemention is different from NVIDIA’s example. No player supports this feature now except QtAV. The performance is improved but still worse than DXVA 0-copy.
CPU usage (sintel_4k.mov from https://download.blender.org/durian/movies/ + GT750M)