summaryrefslogtreecommitdiff
path: root/examples/multimedia/spectrum/app/spectrumanalyser.cpp
blob: 6199221d1062ad5509d546fea284983282c6954c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** 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 The Qt Company Ltd 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)
#ifndef DISABLE_FFT
    ,   m_fft(new FFTRealWrapper)
#endif
    ,   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()
{
#ifndef DISABLE_FFT
    delete m_fft;
#endif
}

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)
{
#ifndef DISABLE_FFT
    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 = qSqrt(real*real + imag*imag);
        qreal amplitude = SpectrumAnalyserMultiplier * qLn(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;
    }
#endif

    emit calculationComplete(m_spectrum);
}


//=============================================================================
// SpectrumAnalyser
//=============================================================================

SpectrumAnalyser::SpectrumAnalyser(QObject *parent)
    :   QObject(parent)
    ,   m_thread(new SpectrumAnalyserThread(this))
    ,   m_state(Idle)
#ifdef DUMP_SPECTRUMANALYSER
    ,   m_count(0)
#endif
{
    CHECKED_CONNECT(m_thread, SIGNAL(calculationComplete(FrequencySpectrum)),
                    this, SLOT(calculationComplete(FrequencySpectrum)));
}

SpectrumAnalyser::~SpectrumAnalyser()
{

}

#ifdef DUMP_SPECTRUMANALYSER
void SpectrumAnalyser::setOutputPath(const QString &outputDir)
{
    m_outputDir.setPath(outputDir);
    m_textFile.setFileName(m_outputDir.filePath("spectrum.txt"));
    m_textFile.open(QIODevice::WriteOnly | QIODevice::Text);
    m_textStream.setDevice(&m_textFile);
}
#endif

//-----------------------------------------------------------------------------
// 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;

#ifdef DUMP_SPECTRUMANALYSER
        m_count++;
        const QString pcmFileName = m_outputDir.filePath(QString("spectrum_%1.pcm").arg(m_count, 4, 10, QChar('0')));
        QFile pcmFile(pcmFileName);
        pcmFile.open(QIODevice::WriteOnly);
        const int bufferLength = m_numSamples * bytesPerSample;
        pcmFile.write(buffer, bufferLength);

        m_textStream << "TimeDomain " << m_count << "\n";
        const qint16* input = reinterpret_cast<const qint16*>(buffer);
        for (int i=0; i<m_numSamples; ++i) {
            m_textStream << i << "\t" << *input << "\n";
            input += format.channels();
        }
#endif

        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

#ifdef DUMP_SPECTRUMANALYSER
        m_textStream << "FrequencySpectrum " << m_count << "\n";
        FrequencySpectrum::const_iterator x = m_spectrum.begin();
        for (int i=0; i<m_numSamples; ++i, ++x)
            m_textStream << i << "\t"
                         << x->frequency << "\t"
                         << x->amplitude<< "\t"
                         << x->phase << "\n";
#endif
    }
}

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;
}