engine.h Example File
demos/spectrum/app/engine.h
 
 
 #ifndef ENGINE_H
 #define ENGINE_H
 #include "spectrum.h"
 #include "spectrumanalyser.h"
 #include "wavfile.h"
 #include <QObject>
 #include <QByteArray>
 #include <QBuffer>
 #include <QVector>
 #include <QtMultimedia/QAudioDeviceInfo>
 #include <QtMultimedia/QAudioFormat>
 #ifdef DUMP_CAPTURED_AUDIO
 #define DUMP_DATA
 #endif
 #ifdef DUMP_SPECTRUM
 #define DUMP_DATA
 #endif
 #ifdef DUMP_DATA
 #include <QDir>
 #endif
 class FrequencySpectrum;
 QT_FORWARD_DECLARE_CLASS(QAudioInput)
 QT_FORWARD_DECLARE_CLASS(QAudioOutput)
 QT_FORWARD_DECLARE_CLASS(QFile)
 
 class Engine : public QObject {
     Q_OBJECT
 public:
     Engine(QObject *parent = 0);
     ~Engine();
     const QList<QAudioDeviceInfo>& availableAudioInputDevices() const
                                     { return m_availableAudioInputDevices; }
     const QList<QAudioDeviceInfo>& availableAudioOutputDevices() const
                                     { return m_availableAudioOutputDevices; }
     QAudio::Mode mode() const       { return m_mode; }
     QAudio::State state() const     { return m_state; }
     
     const QAudioFormat& format() const  { return m_format; }
     
     void reset();
     
     bool loadFile(const QString &fileName);
     
     bool generateTone(const Tone &tone);
     
     bool generateSweptTone(qreal amplitude);
     
     bool initializeRecord();
     
     qint64 recordPosition() const   { return m_recordPosition; }
     
     qreal rmsLevel() const          { return m_rmsLevel; }
     
     qreal peakLevel() const         { return m_peakLevel; }
     
     qint64 playPosition() const     { return m_playPosition; }
     
     qint64 bufferLength() const;
     
     qint64 dataLength() const       { return m_dataLength; }
     
     void setWindowFunction(WindowFunction type);
 public slots:
     void startRecording();
     void startPlayback();
     void suspend();
     void setAudioInputDevice(const QAudioDeviceInfo &device);
     void setAudioOutputDevice(const QAudioDeviceInfo &device);
 signals:
     void stateChanged(QAudio::Mode mode, QAudio::State state);
     
     void infoMessage(const QString &message, int durationMs);
     
     void errorMessage(const QString &heading, const QString &detail);
     
     void formatChanged(const QAudioFormat &format);
     
     void bufferLengthChanged(qint64 duration);
     
     void dataLengthChanged(qint64 duration);
     
     void recordPositionChanged(qint64 position);
     
     void playPositionChanged(qint64 position);
     
     void levelChanged(qreal rmsLevel, qreal peakLevel, int numSamples);
     
     void spectrumChanged(qint64 position, qint64 length, const FrequencySpectrum &spectrum);
     
     void bufferChanged(qint64 position, qint64 length, const QByteArray &buffer);
 private slots:
     void audioNotify();
     void audioStateChanged(QAudio::State state);
     void audioDataReady();
     void spectrumChanged(const FrequencySpectrum &spectrum);
 private:
     void resetAudioDevices();
     bool initialize();
     bool selectFormat();
     void stopRecording();
     void stopPlayback();
     void setState(QAudio::State state);
     void setState(QAudio::Mode mode, QAudio::State state);
     void setFormat(const QAudioFormat &format);
     void setRecordPosition(qint64 position, bool forceEmit = false);
     void setPlayPosition(qint64 position, bool forceEmit = false);
     void calculateLevel(qint64 position, qint64 length);
     void calculateSpectrum(qint64 position);
     void setLevel(qreal rmsLevel, qreal peakLevel, int numSamples);
 #ifdef DUMP_DATA
     void createOutputDir();
     QString outputPath() const { return m_outputDir.path(); }
 #endif
 #ifdef DUMP_CAPTURED_AUDIO
     void dumpData();
 #endif
 private:
     QAudio::Mode        m_mode;
     QAudio::State       m_state;
     bool                m_generateTone;
     SweptTone           m_tone;
     WavFile*            m_file;
     
     
     WavFile*            m_analysisFile;
     QAudioFormat        m_format;
     const QList<QAudioDeviceInfo> m_availableAudioInputDevices;
     QAudioDeviceInfo    m_audioInputDevice;
     QAudioInput*        m_audioInput;
     QIODevice*          m_audioInputIODevice;
     qint64              m_recordPosition;
     const QList<QAudioDeviceInfo> m_availableAudioOutputDevices;
     QAudioDeviceInfo    m_audioOutputDevice;
     QAudioOutput*       m_audioOutput;
     qint64              m_playPosition;
     QBuffer             m_audioOutputIODevice;
     QByteArray          m_buffer;
     qint64              m_bufferPosition;
     qint64              m_bufferLength;
     qint64              m_dataLength;
     int                 m_levelBufferLength;
     qreal               m_rmsLevel;
     qreal               m_peakLevel;
     int                 m_spectrumBufferLength;
     QByteArray          m_spectrumBuffer;
     SpectrumAnalyser    m_spectrumAnalyser;
     qint64              m_spectrumPosition;
     int                 m_count;
 #ifdef DUMP_DATA
     QDir                m_outputDir;
 #endif
 };
 #endif // ENGINE_H