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    41 

    42 #include "spectrumanalyser.h"

    43 #include "utils.h"

    44 

    45 #include <QtCore/qmath.h>

    46 #include <QtCore/qmetatype.h>

    47 #include <QtMultimedia/QAudioFormat>

    48 #include <QThread>

    49 

    50 #include "fftreal_wrapper.h"

    51 

    52 SpectrumAnalyserThread::SpectrumAnalyserThread(QObject *parent)

    53     :   QObject(parent)

    54 #ifndef DISABLE_FFT

    55     ,   m_fft(new FFTRealWrapper)

    56 #endif

    57     ,   m_numSamples(SpectrumLengthSamples)

    58     ,   m_windowFunction(DefaultWindowFunction)

    59     ,   m_window(SpectrumLengthSamples, 0.0)

    60     ,   m_input(SpectrumLengthSamples, 0.0)

    61     ,   m_output(SpectrumLengthSamples, 0.0)

    62     ,   m_spectrum(SpectrumLengthSamples)

    63 #ifdef SPECTRUM_ANALYSER_SEPARATE_THREAD

    64     ,   m_thread(new QThread(this))

    65 #endif

    66 {

    67 #ifdef SPECTRUM_ANALYSER_SEPARATE_THREAD

    68     moveToThread(m_thread);

    69     m_thread->start();

    70 #endif

    71     calculateWindow();

    72 }

    73 

    74 SpectrumAnalyserThread::~SpectrumAnalyserThread()

    75 {

    76 #ifndef DISABLE_FFT

    77     delete m_fft;

    78 #endif

    79 }

    80 

    81 void SpectrumAnalyserThread::setWindowFunction(WindowFunction type)

    82 {

    83     m_windowFunction = type;

    84     calculateWindow();

    85 }

    86 

    87 void SpectrumAnalyserThread::calculateWindow()

    88 {

    89     for (int i=0; i<m_numSamples; ++i) {

    90         DataType x = 0.0;

    91 

    92         switch (m_windowFunction) {

    93         case NoWindow:

    94             x = 1.0;

    95             break;

    96         case HannWindow:

    97             x = 0.5 * (1 - qCos((2 * M_PI * i) / (m_numSamples - 1)));

    98             break;

    99         default:

   100             Q_ASSERT(false);

   101         }

   102 

   103         m_window[i] = x;

   104     }

   105 }

   106 

   107 void SpectrumAnalyserThread::calculateSpectrum(const QByteArray &buffer,

   108                                                 int inputFrequency,

   109                                                 int bytesPerSample)

   110 {

   111 #ifndef DISABLE_FFT

   112     Q_ASSERT(buffer.size() == m_numSamples * bytesPerSample);

   113 

   114     // Initialize data array

   115     const char *ptr = buffer.constData();

   116     for (int i=0; i<m_numSamples; ++i) {

   117         const qint16 pcmSample = *reinterpret_cast<const qint16*>(ptr);

   118         // Scale down to range [-1.0, 1.0]

   119         const DataType realSample = pcmToReal(pcmSample);

   120         const DataType windowedSample = realSample * m_window[i];

   121         m_input[i] = windowedSample;

   122         ptr += bytesPerSample;

   123     }

   124 

   125     // Calculate the FFT

   126     m_fft->calculateFFT(m_output.data(), m_input.data());

   127 

   128     // Analyse output to obtain amplitude and phase for each frequency

   129     for (int i=2; i<=m_numSamples/2; ++i) {

   130         // Calculate frequency of this complex sample

   131         m_spectrum[i].frequency = qreal(i * inputFrequency) / (m_numSamples);

   132 

   133         const qreal real = m_output[i];

   134         qreal imag = 0.0;

   135         if (i>0 && i<m_numSamples/2)

   136             imag = m_output[m_numSamples/2 + i];

   137 

   138         const qreal magnitude = sqrt(real*real + imag*imag);

   139         qreal amplitude = SpectrumAnalyserMultiplier * log(magnitude);

   140 

   141         // Bound amplitude to [0.0, 1.0]

   142         m_spectrum[i].clipped = (amplitude > 1.0);

   143         amplitude = qMax(qreal(0.0), amplitude);

   144         amplitude = qMin(qreal(1.0), amplitude);

   145         m_spectrum[i].amplitude = amplitude;

   146     }

   147 #endif

   148 

   149     emit calculationComplete(m_spectrum);

   150 }

   151 

   152 

   153 //=============================================================================

   154 // SpectrumAnalyser

   155 //=============================================================================

   156 

   157 SpectrumAnalyser::SpectrumAnalyser(QObject *parent)

   158     :   QObject(parent)

   159     ,   m_thread(new SpectrumAnalyserThread(this))

   160     ,   m_state(Idle)

   161 #ifdef DUMP_SPECTRUMANALYSER

   162     ,   m_count(0)

   163 #endif

   164 {

   165     CHECKED_CONNECT(m_thread, SIGNAL(calculationComplete(FrequencySpectrum)),

   166                     this, SLOT(calculationComplete(FrequencySpectrum)));

   167 }

   168 

   169 SpectrumAnalyser::~SpectrumAnalyser()

   170 {

   171 

   172 }

   173 

   174 #ifdef DUMP_SPECTRUMANALYSER

   175 void SpectrumAnalyser::setOutputPath(const QString &outputDir)

   176 {

   177     m_outputDir.setPath(outputDir);

   178     m_textFile.setFileName(m_outputDir.filePath("spectrum.txt"));

   179     m_textFile.open(QIODevice::WriteOnly | QIODevice::Text);

   180     m_textStream.setDevice(&m_textFile);

   181 }

   182 #endif

   183 

   184 //-----------------------------------------------------------------------------

   185 // Public functions

   186 //-----------------------------------------------------------------------------

   187 

   188 void SpectrumAnalyser::setWindowFunction(WindowFunction type)

   189 {

   190     const bool b = QMetaObject::invokeMethod(m_thread, "setWindowFunction",

   191                               Qt::AutoConnection,

   192                               Q_ARG(WindowFunction, type));

   193     Q_ASSERT(b);

   194     Q_UNUSED(b) // suppress warnings in release builds

   195 }

   196 

   197 void SpectrumAnalyser::calculate(const QByteArray &buffer,

   198                          const QAudioFormat &format)

   199 {

   200     // QThread::currentThread is marked 'for internal use only', but

   201     // we're only using it for debug output here, so it's probably OK :)

   202     SPECTRUMANALYSER_DEBUG << "SpectrumAnalyser::calculate"

   203                            << QThread::currentThread()

   204                            << "state" << m_state;

   205 

   206     if (isReady()) {

   207         Q_ASSERT(isPCMS16LE(format));

   208 

   209         const int bytesPerSample = format.sampleSize() * format.channels() / 8;

   210 

   211 #ifdef DUMP_SPECTRUMANALYSER

   212         m_count++;

   213         const QString pcmFileName = m_outputDir.filePath(QString("spectrum_%1.pcm").arg(m_count, 4, 10, QChar('0')));

   214         QFile pcmFile(pcmFileName);

   215         pcmFile.open(QIODevice::WriteOnly);

   216         const int bufferLength = m_numSamples * bytesPerSample;

   217         pcmFile.write(buffer, bufferLength);

   218 

   219         m_textStream << "TimeDomain " << m_count << "\n";

   220         const qint16* input = reinterpret_cast<const qint16*>(buffer);

   221         for (int i=0; i<m_numSamples; ++i) {

   222             m_textStream << i << "\t" << *input << "\n";

   223             input += format.channels();

   224         }

   225 #endif

   226 

   227         m_state = Busy;

   228 

   229         // Invoke SpectrumAnalyserThread::calculateSpectrum using QMetaObject.  If

   230         // m_thread is in a different thread from the current thread, the

   231         // calculation will be done in the child thread.

   232         // Once the calculation is finished, a calculationChanged signal will be

   233         // emitted by m_thread.

   234         const bool b = QMetaObject::invokeMethod(m_thread, "calculateSpectrum",

   235                                   Qt::AutoConnection,

   236                                   Q_ARG(QByteArray, buffer),

   237                                   Q_ARG(int, format.frequency()),

   238                                   Q_ARG(int, bytesPerSample));

   239         Q_ASSERT(b);

   240         Q_UNUSED(b) // suppress warnings in release builds

   241 

   242 #ifdef DUMP_SPECTRUMANALYSER

   243         m_textStream << "FrequencySpectrum " << m_count << "\n";

   244         FrequencySpectrum::const_iterator x = m_spectrum.begin();

   245         for (int i=0; i<m_numSamples; ++i, ++x)

   246             m_textStream << i << "\t"

   247                          << x->frequency << "\t"

   248                          << x->amplitude<< "\t"

   249                          << x->phase << "\n";

   250 #endif

   251     }

   252 }

   253 

   254 bool SpectrumAnalyser::isReady() const

   255 {

   256     return (Idle == m_state);

   257 }

   258 

   259 void SpectrumAnalyser::cancelCalculation()

   260 {

   261     if (Busy == m_state)

   262         m_state = Cancelled;

   263 }

   264 

   265 

   266 //-----------------------------------------------------------------------------

   267 // Private slots

   268 //-----------------------------------------------------------------------------

   269 

   270 void SpectrumAnalyser::calculationComplete(const FrequencySpectrum &spectrum)

   271 {

   272     Q_ASSERT(Idle != m_state);

   273     if (Busy == m_state)

   274         emit spectrumChanged(spectrum);

   275     m_state = Idle;

   276 }

   277 

   278 

   279 

   280