1 files changed, 151 insertions, 0 deletions
diff --git a/examples/multimedia/spectrum/spectrumanalyser.h b/examples/multimedia/spectrum/spectrumanalyser.h
new file mode 100644
index 000000000..202e602fe
--- /dev/null
+++ b/examples/multimedia/spectrum/spectrumanalyser.h
@@ -0,0 +1,151 @@
+// Copyright (C) 2017 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#ifndef SPECTRUMANALYSER_H
+#define SPECTRUMANALYSER_H
+
+#include "frequencyspectrum.h"
+#include "spectrum.h"
+
+#include <QByteArray>
+#include <QList>
+#include <QObject>
+
+#ifdef DUMP_SPECTRUMANALYSER
+#    include <QDir>
+#    include <QFile>
+#    include <QTextStream>
+#endif
+
+#ifndef DISABLE_FFT
+#    include "FFTRealFixLenParam.h"
+#endif
+
+QT_FORWARD_DECLARE_CLASS(QAudioFormat)
+QT_FORWARD_DECLARE_CLASS(QThread)
+
+class FFTRealWrapper;
+
+class SpectrumAnalyserThreadPrivate;
+
+/**
+ * Implementation of the spectrum analysis which can be run in a
+ * separate thread.
+ */
+class SpectrumAnalyserThread : public QObject
+{
+    Q_OBJECT
+
+public:
+    SpectrumAnalyserThread(QObject *parent);
+    ~SpectrumAnalyserThread();
+
+public slots:
+    void setWindowFunction(WindowFunction type);
+    void calculateSpectrum(const QByteArray &buffer, int inputFrequency, int bytesPerSample);
+
+signals:
+    void calculationComplete(const FrequencySpectrum &spectrum);
+
+private:
+    void calculateWindow();
+
+private:
+#ifndef DISABLE_FFT
+    FFTRealWrapper *m_fft;
+#endif
+
+    const int m_numSamples;
+
+    WindowFunction m_windowFunction;
+
+#ifdef DISABLE_FFT
+    typedef qreal DataType;
+#else
+    typedef FFTRealFixLenParam::DataType DataType;
+#endif
+    QList<DataType> m_window;
+
+    QList<DataType> m_input;
+    QList<DataType> m_output;
+
+    FrequencySpectrum m_spectrum;
+
+#ifdef SPECTRUM_ANALYSER_SEPARATE_THREAD
+    QThread *m_thread;
+#endif
+};
+
+/**
+ * Class which performs frequency spectrum analysis on a window of
+ * audio samples, provided to it by the Engine.
+ */
+class SpectrumAnalyser : public QObject
+{
+    Q_OBJECT
+
+public:
+    SpectrumAnalyser(QObject *parent = nullptr);
+    ~SpectrumAnalyser();
+
+#ifdef DUMP_SPECTRUMANALYSER
+    void setOutputPath(const QString &outputPath);
+#endif
+
+public:
+    /*
+     * Set the windowing function which is applied before calculating the FFT
+     */
+    void setWindowFunction(WindowFunction type);
+
+    /*
+     * Calculate a frequency spectrum
+     *
+     * \param buffer       Audio data
+     * \param format       Format of audio data
+     *
+     * Frequency spectrum is calculated asynchronously.  The result is returned
+     * via the spectrumChanged signal.
+     *
+     * An ongoing calculation can be cancelled by calling cancelCalculation().
+     *
+     */
+    void calculate(const QByteArray &buffer, const QAudioFormat &format);
+
+    /*
+     * Check whether the object is ready to perform another calculation
+     */
+    bool isReady() const;
+
+    /*
+     * Cancel an ongoing calculation
+     *
+     * Note that cancelling is asynchronous.
+     */
+    void cancelCalculation();
+
+signals:
+    void spectrumChanged(const FrequencySpectrum &spectrum);
+
+private slots:
+    void calculationComplete(const FrequencySpectrum &spectrum);
+
+private:
+    void calculateWindow();
+
+private:
+    SpectrumAnalyserThread *m_thread;
+
+    enum State { Idle, Busy, Cancelled };
+
+    State m_state;
+
+#ifdef DUMP_SPECTRUMANALYSER
+    QDir m_outputDir;
+    int m_count;
+    QFile m_textFile;
+    QTextStream m_textStream;
+#endif
+};
+
+#endif // SPECTRUMANALYSER_H