Conversion of an configuration settings file (.ini) to json format

I have a configuration settings file (.ini) like declared in the code :

Volumes::Volumes(QWidget *parent) :
QDialog(parent),
ui(new Ui::Volumes), m_settings(new QSettings(qAppName() + ".ini", QSettings::IniFormat))

What I want to do is to save those settings, like I did in file.ini, but not as an ini file, but as json format. How can I do that ? Is there a possibility to declare the file from the beginning as json file ? ( It would be better ) Otherwise, how can I convert the .ini file that I have to json format ?