#include <QtCore/QDir>
#include <QtCore/QFileInfo>
#include <QtCore/QTimer>
#include <QtCore/QUrl>
#include <QtMultimedia/QAudioRecorder>
#include <QtWidgets/QApplication>
#include <QtWidgets/QMainWindow>

struct main_window : QMainWindow
{
    main_window()
    {
        recorder_.setOutputLocation( QUrl::fromLocalFile( filepath_ ) );
        recorder_.record();

        startTimer( 2000 );

        connect( &recorder_, &QAudioRecorder::stateChanged, this, &main_window::on_state_changed );
    }

    void timerEvent( QTimerEvent* /*e*/ ) override
    {
        if( recorder_.state() == QAudioRecorder::RecordingState )
        {
            recorder_.stop();
        }
        else
        {
            qInfo() << QFileInfo( filepath_ ).size();
            QDir().remove( filepath_ );

            close();
        }
    }

    void on_state_changed( QAudioRecorder::State state )
    {
        if( state == QAudioRecorder::StoppedState )
            qInfo() << QFileInfo( filepath_ ).size();
    }

    const QString  filepath_ { "/tmp/_test_qaudiorecorder" };
    QAudioRecorder recorder_;
};

int main( int argc, char** argv )
{
    QApplication a { argc, argv };

    main_window w;
    w.show();

    return a.exec();
}