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// Copyright (C) 2017 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "audiooutput.h"
#include <QAudioDevice>
#include <QAudioSink>
#include <QDebug>
#include <QVBoxLayout>
#include <qmath.h>
#include <qendian.h>
Generator::Generator(const QAudioFormat &format, qint64 durationUs, int sampleRate)
{
if (format.isValid())
generateData(format, durationUs, sampleRate);
}
void Generator::start()
{
open(QIODevice::ReadOnly);
}
void Generator::stop()
{
m_pos = 0;
close();
}
void Generator::generateData(const QAudioFormat &format, qint64 durationUs, int sampleRate)
{
const int channelBytes = format.bytesPerSample();
const int sampleBytes = format.channelCount() * channelBytes;
qint64 length = format.bytesForDuration(durationUs);
Q_ASSERT(length % sampleBytes == 0);
Q_UNUSED(sampleBytes); // suppress warning in release builds
m_buffer.resize(length);
unsigned char *ptr = reinterpret_cast<unsigned char *>(m_buffer.data());
int sampleIndex = 0;
while (length) {
// Produces value (-1..1)
const qreal x = qSin(2 * M_PI * sampleRate * qreal(sampleIndex++ % format.sampleRate()) / format.sampleRate());
for (int i=0; i<format.channelCount(); ++i) {
switch(format.sampleFormat()) {
case QAudioFormat::UInt8:
*reinterpret_cast<quint8 *>(ptr) = static_cast<quint8>((1.0 + x) / 2 * 255);
break;
case QAudioFormat::Int16:
*reinterpret_cast<qint16 *>(ptr) = static_cast<qint16>(x * 32767);
break;
case QAudioFormat::Int32:
*reinterpret_cast<qint32 *>(ptr) = static_cast<qint32>(x * std::numeric_limits<qint32>::max());
break;
case QAudioFormat::Float:
*reinterpret_cast<float *>(ptr) = x;
break;
default:
break;
}
ptr += channelBytes;
length -= channelBytes;
}
}
}
qint64 Generator::readData(char *data, qint64 len)
{
qint64 total = 0;
if (!m_buffer.isEmpty()) {
while (len - total > 0) {
const qint64 chunk = qMin((m_buffer.size() - m_pos), len - total);
memcpy(data + total, m_buffer.constData() + m_pos, chunk);
m_pos = (m_pos + chunk) % m_buffer.size();
total += chunk;
}
}
return total;
}
qint64 Generator::writeData(const char *data, qint64 len)
{
Q_UNUSED(data);
Q_UNUSED(len);
return 0;
}
qint64 Generator::bytesAvailable() const
{
return m_buffer.size() + QIODevice::bytesAvailable();
}
AudioTest::AudioTest()
: m_devices(new QMediaDevices(this)),
m_pushTimer(new QTimer(this))
{
initializeWindow();
initializeAudio(m_devices->defaultAudioOutput());
}
AudioTest::~AudioTest()
{
m_pushTimer->stop();
}
void AudioTest::initializeWindow()
{
QWidget *window = new QWidget;
QVBoxLayout *layout = new QVBoxLayout;
m_deviceBox = new QComboBox(this);
const QAudioDevice &defaultDeviceInfo = m_devices->defaultAudioOutput();
m_deviceBox->addItem(defaultDeviceInfo.description(), QVariant::fromValue(defaultDeviceInfo));
for (auto &deviceInfo: m_devices->audioOutputs()) {
if (deviceInfo != defaultDeviceInfo)
m_deviceBox->addItem(deviceInfo.description(), QVariant::fromValue(deviceInfo));
}
connect(m_deviceBox, QOverload<int>::of(&QComboBox::activated), this, &AudioTest::deviceChanged);
connect(m_devices, &QMediaDevices::audioOutputsChanged, this, &AudioTest::updateAudioDevices);
layout->addWidget(m_deviceBox);
m_modeButton = new QPushButton(this);
connect(m_modeButton, &QPushButton::clicked, this, &AudioTest::toggleMode);
layout->addWidget(m_modeButton);
m_suspendResumeButton = new QPushButton(this);
connect(m_suspendResumeButton, &QPushButton::clicked, this, &AudioTest::toggleSuspendResume);
layout->addWidget(m_suspendResumeButton);
QHBoxLayout *volumeBox = new QHBoxLayout;
m_volumeLabel = new QLabel;
m_volumeLabel->setText(tr("Volume:"));
m_volumeSlider = new QSlider(Qt::Horizontal);
m_volumeSlider->setMinimum(0);
m_volumeSlider->setMaximum(100);
m_volumeSlider->setSingleStep(10);
connect(m_volumeSlider, &QSlider::valueChanged, this, &AudioTest::volumeChanged);
volumeBox->addWidget(m_volumeLabel);
volumeBox->addWidget(m_volumeSlider);
layout->addLayout(volumeBox);
window->setLayout(layout);
setCentralWidget(window);
window->show();
}
void AudioTest::initializeAudio(const QAudioDevice &deviceInfo)
{
QAudioFormat format = deviceInfo.preferredFormat();
const int durationSeconds = 1;
const int toneSampleRateHz = 600;
m_generator.reset(new Generator(format, durationSeconds * 1000000, toneSampleRateHz));
m_audioOutput.reset(new QAudioSink(deviceInfo, format));
m_generator->start();
qreal initialVolume = QAudio::convertVolume(m_audioOutput->volume(),
QAudio::LinearVolumeScale,
QAudio::LogarithmicVolumeScale);
m_volumeSlider->setValue(qRound(initialVolume * 100));
toggleMode();
}
void AudioTest::deviceChanged(int index)
{
m_generator->stop();
m_audioOutput->stop();
m_audioOutput->disconnect(this);
initializeAudio(m_deviceBox->itemData(index).value<QAudioDevice>());
}
void AudioTest::volumeChanged(int value)
{
qreal linearVolume = QAudio::convertVolume(value / qreal(100),
QAudio::LogarithmicVolumeScale,
QAudio::LinearVolumeScale);
m_audioOutput->setVolume(linearVolume);
}
void AudioTest::updateAudioDevices()
{
m_deviceBox->clear();
const QList<QAudioDevice> devices = m_devices->audioOutputs();
for (const QAudioDevice &deviceInfo: devices)
m_deviceBox->addItem(deviceInfo.description(), QVariant::fromValue(deviceInfo));
}
void AudioTest::toggleMode()
{
m_pushTimer->stop();
m_audioOutput->stop();
toggleSuspendResume();
if (m_pullMode) {
//switch to pull mode (QAudioSink pulls from Generator as needed)
m_modeButton->setText(tr("Enable push mode"));
m_audioOutput->start(m_generator.data());
} else {
//switch to push mode (periodically push to QAudioSink using a timer)
m_modeButton->setText(tr("Enable pull mode"));
auto io = m_audioOutput->start();
m_pushTimer->disconnect();
connect(m_pushTimer, &QTimer::timeout, [this, io]() {
if (m_audioOutput->state() == QAudio::StoppedState)
return;
int len = m_audioOutput->bytesFree();
QByteArray buffer(len, 0);
len = m_generator->read(buffer.data(), len);
if (len)
io->write(buffer.data(), len);
});
m_pushTimer->start(10);
}
m_pullMode = !m_pullMode;
}
void AudioTest::toggleSuspendResume()
{
if (m_audioOutput->state() == QAudio::SuspendedState || m_audioOutput->state() == QAudio::StoppedState) {
m_audioOutput->resume();
m_suspendResumeButton->setText(tr("Suspend playback"));
} else if (m_audioOutput->state() == QAudio::ActiveState) {
m_audioOutput->suspend();
m_suspendResumeButton->setText(tr("Resume playback"));
} else if (m_audioOutput->state() == QAudio::IdleState) {
// no-op
}
}
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