QAudioDecoder() fails in Windows 7

[HereWeAre]

Creating a QAudioDecoder fails in Windows 7 with the error:
defaultServiceProvider::requestService(): no service found for - "org.qt-project.qt.audiodecode"

Code:

QAudioDecoder decoder = new QAudioDecoder();

I tried using Qt versions 5.4 and 5.5.1 on Windows 7 and got the error both times. The code runs fine in Ubuntu.
I have
QT += core gui widgets multimedia in my .pro file.

[HereWeAre]

Eventually figured it out. I had to install microsoft visual studio 2013 and add the compiler to Qt Creator (projects->manage kits->msvc2013). Then QAudioDecoder works correctly.