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
|
// Copyright (C) 2017 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#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(nullptr);
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 bytesPerFrame)
{
#ifndef DISABLE_FFT
Q_ASSERT(buffer.size() == m_numSamples * bytesPerFrame);
// 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 += bytesPerFrame;
}
// 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
{
connect(m_thread, &SpectrumAnalyserThread::calculationComplete,
this, &SpectrumAnalyser::calculationComplete);
}
SpectrumAnalyser::~SpectrumAnalyser() = default;
#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(format.sampleFormat() == QAudioFormat::Int16);
const int bytesPerFrame = format.bytesPerFrame();
#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 * bytesPerFrame;
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, bytesPerFrame));
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;
}
|
