- Qt 5.3
- Qt Multimedia
- Audio Output Example
- audiooutput.h Example File
- Qt 5.3.2 Reference Documentation

# audiooutput.h Example File

audiooutput/audiooutput.h

    /****************************************************************************
    **
    ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
    ** Contact: http://www.qt-project.org/legal
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
    **
    ** "Redistribution and use in source and binary forms, with or without
    ** modification, are permitted provided that the following conditions are
    ** met:
    **   * Redistributions of source code must retain the above copyright
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    **     notice, this list of conditions and the following disclaimer in
    **     the documentation and/or other materials provided with the
    **     distribution.
    **   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
    **     of its contributors may be used to endorse or promote products derived
    **     from this software without specific prior written permission.
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    #ifndef AUDIOOUTPUT_H
    #define AUDIOOUTPUT_H

    #include <math.h>

    #include <QAudioOutput>
    #include <QByteArray>
    #include <QComboBox>
    #include <QIODevice>
    #include <QLabel>
    #include <QMainWindow>
    #include <QObject>
    #include <QPushButton>
    #include <QSlider>
    #include <QTimer>

    class Generator : public QIODevice
    {
        Q_OBJECT

    public:
        Generator(const QAudioFormat &format, qint64 durationUs, int sampleRate, QObject *parent);
        ~Generator();

        void start();
        void stop();

        qint64 readData(char *data, qint64 maxlen);
        qint64 writeData(const char *data, qint64 len);
        qint64 bytesAvailable() const;

    private:
        void generateData(const QAudioFormat &format, qint64 durationUs, int sampleRate);

    private:
        qint64 m_pos;
        QByteArray m_buffer;
    };

    class AudioTest : public QMainWindow
    {
        Q_OBJECT

    public:
        AudioTest();
        ~AudioTest();

    private:
        void initializeWindow();
        void initializeAudio();
        void createAudioOutput();

    private:
        QTimer *m_pullTimer;

        // Owned by layout
        QPushButton *m_modeButton;
        QPushButton *m_suspendResumeButton;
        QComboBox *m_deviceBox;
        QLabel *m_volumeLabel;
        QSlider *m_volumeSlider;

        QAudioDeviceInfo m_device;
        Generator *m_generator;
        QAudioOutput *m_audioOutput;
        QIODevice *m_output; // not owned
        QAudioFormat m_format;

        bool m_pullMode;
        QByteArray m_buffer;

    private slots:
        void notified();
        void pullTimerExpired();
        void toggleMode();
        void toggleSuspendResume();
        void handleStateChanged(QAudio::State state);
        void deviceChanged(int index);
        void volumeChanged(int);
    };

    #endif // AUDIOOUTPUT_H