Spectrum Example▲
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#ifndef ENGINE_H
#define ENGINE_H
#include "spectrum.h"
#include "spectrumanalyser.h"
#include "wavfile.h"
#include <QAudioDeviceInfo>
#include <QAudioFormat>
#include <QBuffer>
#include <QByteArray>
#include <QDir>
#include <QObject>
#include <QVector>
#ifdef DUMP_CAPTURED_AUDIO
#define DUMP_DATA
#endif
#ifdef DUMP_SPECTRUM
#define DUMP_DATA
#endif
class FrequencySpectrum;
class QAudioInput;
class QAudioOutput;
/**
* This class interfaces with the Qt Multimedia audio classes, and also with
* the SpectrumAnalyser class. Its role is to manage the capture and playback
* of audio data, meanwhile performing real-time analysis of the audio level
* and frequency spectrum.
*/
class Engine : public QObject
{
Q_OBJECT
public:
explicit 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; }
/**
* \return Current audio format
* \note May be QAudioFormat() if engine is not initialized
*/
const QAudioFormat& format() const { return m_format; }
/**
* Stop any ongoing recording or playback, and reset to ground state.
*/
void reset();
/**
* Load data from WAV file
*/
bool loadFile(const QString &fileName);
/**
* Generate tone
*/
bool generateTone(const Tone &tone);
/**
* Generate tone
*/
bool generateSweptTone(qreal amplitude);
/**
* Initialize for recording
*/
bool initializeRecord();
/**
* Position of the audio input device.
* \return Position in bytes.
*/
qint64 recordPosition() const { return m_recordPosition; }
/**
* RMS level of the most recently processed set of audio samples.
* \return Level in range (0.0, 1.0)
*/
qreal rmsLevel() const { return m_rmsLevel; }
/**
* Peak level of the most recently processed set of audio samples.
* \return Level in range (0.0, 1.0)
*/
qreal peakLevel() const { return m_peakLevel; }
/**
* Position of the audio output device.
* \return Position in bytes.
*/
qint64 playPosition() const { return m_playPosition; }
/**
* Length of the internal engine buffer.
* \return Buffer length in bytes.
*/
qint64 bufferLength() const;
/**
* Amount of data held in the buffer.
* \return Data length in bytes.
*/
qint64 dataLength() const { return m_dataLength; }
/**
* Set window function applied to audio data before spectral analysis.
*/
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);
/**
* Informational message for non-modal display
*/
void infoMessage(const QString &message, int durationMs);
/**
* Error message for modal display
*/
void errorMessage(const QString &heading, const QString &detail);
/**
* Format of audio data has changed
*/
void formatChanged(const QAudioFormat &format);
/**
* Length of buffer has changed.
* \param duration Duration in microseconds
*/
void bufferLengthChanged(qint64 duration);
/**
* Amount of data in buffer has changed.
* \param Length of data in bytes
*/
void dataLengthChanged(qint64 duration);
/**
* Position of the audio input device has changed.
* \param position Position in bytes
*/
void recordPositionChanged(qint64 position);
/**
* Position of the audio output device has changed.
* \param position Position in bytes
*/
void playPositionChanged(qint64 position);
/**
* Level changed
* \param rmsLevel RMS level in range 0.0 - 1.0
* \param peakLevel Peak level in range 0.0 - 1.0
* \param numSamples Number of audio samples analyzed
*/
void levelChanged(qreal rmsLevel, qreal peakLevel, int numSamples);
/**
* Spectrum has changed.
* \param position Position of start of window in bytes
* \param length Length of window in bytes
* \param spectrum Resulting frequency spectrum
*/
void spectrumChanged(qint64 position, qint64 length, const FrequencySpectrum &spectrum);
/**
* Buffer containing audio data has changed.
* \param position Position of start of buffer in bytes
* \param buffer Buffer
*/
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;
// We need a second file handle via which to read data into m_buffer
// for analysis
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;
QString m_audioOutputCategory;
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