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Diffstat (limited to 'examples/spectrum/spectrumapp/spectrumanalyser.cpp')
| -rw-r--r-- | examples/spectrum/spectrumapp/spectrumanalyser.cpp | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/examples/spectrum/spectrumapp/spectrumanalyser.cpp b/examples/spectrum/spectrumapp/spectrumanalyser.cpp new file mode 100644 index 00000000..518bb6da --- /dev/null +++ b/examples/spectrum/spectrumapp/spectrumanalyser.cpp @@ -0,0 +1,231 @@ +/**************************************************************************** +** +** 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 +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** 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. +** +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "spectrumanalyser.h" +#include "utils.h" +#include "fftreal_wrapper.h" + +#include <qmath.h> +#include <qmetatype.h> +#include <QAudioFormat> +#include <QThread> + +SpectrumAnalyserThread::SpectrumAnalyserThread(QObject *parent) + : QObject(parent), + m_fft(new FFTRealWrapper), + m_numSamples(SpectrumLengthSamples), + m_windowFunction(DefaultWindowFunction), + m_window(SpectrumLengthSamples, 0.0), + m_input(SpectrumLengthSamples, 0.0), + m_output(SpectrumLengthSamples, 0.0), + m_spectrum(SpectrumLengthSamples) + #ifdef SPECTRUM_ANALYSER_SEPARATE_THREAD + , m_thread(new QThread(this)) + #endif +{ +#ifdef SPECTRUM_ANALYSER_SEPARATE_THREAD + // moveToThread() cannot be called on a QObject with a parent + setParent(0); + moveToThread(m_thread); + m_thread->start(); +#endif + calculateWindow(); +} + +SpectrumAnalyserThread::~SpectrumAnalyserThread() +{ + delete m_fft; +} + +void SpectrumAnalyserThread::setWindowFunction(WindowFunction type) +{ + m_windowFunction = type; + calculateWindow(); +} + +void SpectrumAnalyserThread::calculateWindow() +{ + for (int i=0; i<m_numSamples; ++i) { + DataType x = 0.0; + + switch (m_windowFunction) { + case NoWindow: + x = 1.0; + break; + case HannWindow: + x = 0.5 * (1 - qCos((2 * M_PI * i) / (m_numSamples - 1))); + break; + default: + Q_ASSERT(false); + } + + m_window[i] = x; + } +} + +void SpectrumAnalyserThread::calculateSpectrum(const QByteArray &buffer, + int inputFrequency, + int bytesPerSample) +{ + Q_ASSERT(buffer.size() == m_numSamples * bytesPerSample); + + // Initialize data array + const char *ptr = buffer.constData(); + for (int i=0; i<m_numSamples; ++i) { + const qint16 pcmSample = *reinterpret_cast<const qint16*>(ptr); + // Scale down to range [-1.0, 1.0] + const DataType realSample = pcmToReal(pcmSample); + const DataType windowedSample = realSample * m_window[i]; + m_input[i] = windowedSample; + ptr += bytesPerSample; + } + + // Calculate the FFT + m_fft->calculateFFT(m_output.data(), m_input.data()); + + // Analyze output to obtain amplitude and phase for each frequency + for (int i=2; i<=m_numSamples/2; ++i) { + // Calculate frequency of this complex sample + m_spectrum[i].frequency = qreal(i * inputFrequency) / (m_numSamples); + + const qreal real = m_output[i]; + qreal imag = 0.0; + if (i>0 && i<m_numSamples/2) + imag = m_output[m_numSamples/2 + i]; + + const qreal magnitude = sqrt(real*real + imag*imag); + qreal amplitude = SpectrumAnalyserMultiplier * log(magnitude); + + // Bound amplitude to [0.0, 1.0] + m_spectrum[i].clipped = (amplitude > 1.0); + amplitude = qMax(qreal(0.0), amplitude); + amplitude = qMin(qreal(1.0), amplitude); + m_spectrum[i].amplitude = amplitude; + } + + emit calculationComplete(m_spectrum); +} + + +//============================================================================= +// SpectrumAnalyser +//============================================================================= + +SpectrumAnalyser::SpectrumAnalyser(QObject *parent) + : QObject(parent), + m_thread(new SpectrumAnalyserThread(this)), + m_state(Idle) +{ + CHECKED_CONNECT(m_thread, SIGNAL(calculationComplete(FrequencySpectrum)), + this, SLOT(calculationComplete(FrequencySpectrum))); +} + +SpectrumAnalyser::~SpectrumAnalyser() +{ + +} + +//----------------------------------------------------------------------------- +// Public functions +//----------------------------------------------------------------------------- + +void SpectrumAnalyser::setWindowFunction(WindowFunction type) +{ + const bool b = QMetaObject::invokeMethod(m_thread, "setWindowFunction", + Qt::AutoConnection, + Q_ARG(WindowFunction, type)); + Q_ASSERT(b); + Q_UNUSED(b) // suppress warnings in release builds +} + +void SpectrumAnalyser::calculate(const QByteArray &buffer, + const QAudioFormat &format) +{ + // QThread::currentThread is marked 'for internal use only', but + // we're only using it for debug output here, so it's probably OK :) + SPECTRUMANALYSER_DEBUG << "SpectrumAnalyser::calculate" + << QThread::currentThread() + << "state" << m_state; + + if (isReady()) { + Q_ASSERT(isPCMS16LE(format)); + + const int bytesPerSample = format.sampleSize() * format.channelCount() / 8; + + m_state = Busy; + + // Invoke SpectrumAnalyserThread::calculateSpectrum using QMetaObject. If + // m_thread is in a different thread from the current thread, the + // calculation will be done in the child thread. + // Once the calculation is finished, a calculationChanged signal will be + // emitted by m_thread. + const bool b = QMetaObject::invokeMethod(m_thread, "calculateSpectrum", + Qt::AutoConnection, + Q_ARG(QByteArray, buffer), + Q_ARG(int, format.sampleRate()), + Q_ARG(int, bytesPerSample)); + Q_ASSERT(b); + Q_UNUSED(b) // suppress warnings in release builds + } +} + +bool SpectrumAnalyser::isReady() const +{ + return (Idle == m_state); +} + +void SpectrumAnalyser::cancelCalculation() +{ + if (Busy == m_state) + m_state = Cancelled; +} + + +//----------------------------------------------------------------------------- +// Private slots +//----------------------------------------------------------------------------- + +void SpectrumAnalyser::calculationComplete(const FrequencySpectrum &spectrum) +{ + Q_ASSERT(Idle != m_state); + if (Busy == m_state) + emit spectrumChanged(spectrum); + m_state = Idle; +} |