http://qt-project.org/doc/qt-5.0/qaudioinput.html#details
http://qt-project.org/doc/qt-5.0/qaudiooutput.html#details
http://qt-project.org/doc/qt-5.0/qaudiodeviceinfo.html#details

Issue
The "Detailed Description" sections of these class references contain code such as:
QAudioFormat format;
format.setFrequency(8000);
format.setChannels(1);

QAudioFormat::setFrequency() and QAudioFormat::setChannels() have been obsolete since Qt 4.7: http://qt-project.org/doc/qt-5.0/qaudioformat-obsolete.html

Suggestion
Replace obsolete functions with modern, unambiguous versions to aid newcomers: QAudioFormat::setSampleRate() and QAudioFormat::setChannelCount() – Qt 5.0 is a major release, after all