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<h1 class="title">audiooutput.cpp Example File</h1>
<span class="subtitle">multimedia/audiooutput/audiooutput.cpp</span>
<!-- $$$multimedia/audiooutput/audiooutput.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp">
<span class="comment">/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, 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."
**
** $QT_END_LICENSE$
**
****************************************************************************/</span>
<span class="preprocessor">#include <QAudioDeviceInfo></span>
<span class="preprocessor">#include <QAudioOutput></span>
<span class="preprocessor">#include <QDebug></span>
<span class="preprocessor">#include <QVBoxLayout></span>
<span class="preprocessor">#include <qmath.h></span>
<span class="preprocessor">#include <qendian.h></span>
<span class="preprocessor">#include "audiooutput.h"</span>
<span class="preprocessor">#define PUSH_MODE_LABEL "Enable push mode"</span>
<span class="preprocessor">#define PULL_MODE_LABEL "Enable pull mode"</span>
<span class="preprocessor">#define SUSPEND_LABEL "Suspend playback"</span>
<span class="preprocessor">#define RESUME_LABEL "Resume playback"</span>
<span class="preprocessor">#define VOLUME_LABEL "Volume:"</span>
<span class="keyword">const</span> <span class="type">int</span> DurationSeconds <span class="operator">=</span> <span class="number">1</span>;
<span class="keyword">const</span> <span class="type">int</span> ToneSampleRateHz <span class="operator">=</span> <span class="number">600</span>;
<span class="keyword">const</span> <span class="type">int</span> DataSampleRateHz <span class="operator">=</span> <span class="number">44100</span>;
<span class="keyword">const</span> <span class="type">int</span> BufferSize <span class="operator">=</span> <span class="number">32768</span>;
Generator<span class="operator">::</span>Generator(<span class="keyword">const</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> <span class="operator">&</span>format<span class="operator">,</span>
<span class="type">qint64</span> durationUs<span class="operator">,</span>
<span class="type">int</span> sampleRate<span class="operator">,</span>
<span class="type">QObject</span> <span class="operator">*</span>parent)
: <span class="type">QIODevice</span>(parent)
<span class="operator">,</span> m_pos(<span class="number">0</span>)
{
<span class="keyword">if</span> (format<span class="operator">.</span>isValid())
generateData(format<span class="operator">,</span> durationUs<span class="operator">,</span> sampleRate);
}
Generator<span class="operator">::</span><span class="operator">~</span>Generator()
{
}
<span class="type">void</span> Generator<span class="operator">::</span>start()
{
open(<span class="type">QIODevice</span><span class="operator">::</span>ReadOnly);
}
<span class="type">void</span> Generator<span class="operator">::</span>stop()
{
m_pos <span class="operator">=</span> <span class="number">0</span>;
close();
}
<span class="type">void</span> Generator<span class="operator">::</span>generateData(<span class="keyword">const</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> <span class="operator">&</span>format<span class="operator">,</span> <span class="type">qint64</span> durationUs<span class="operator">,</span> <span class="type">int</span> sampleRate)
{
<span class="keyword">const</span> <span class="type">int</span> channelBytes <span class="operator">=</span> format<span class="operator">.</span>sampleSize() <span class="operator">/</span> <span class="number">8</span>;
<span class="keyword">const</span> <span class="type">int</span> sampleBytes <span class="operator">=</span> format<span class="operator">.</span>channelCount() <span class="operator">*</span> channelBytes;
<span class="type">qint64</span> length <span class="operator">=</span> (format<span class="operator">.</span>sampleRate() <span class="operator">*</span> format<span class="operator">.</span>channelCount() <span class="operator">*</span> (format<span class="operator">.</span>sampleSize() <span class="operator">/</span> <span class="number">8</span>))
<span class="operator">*</span> durationUs <span class="operator">/</span> <span class="number">100000</span>;
Q_ASSERT(length <span class="operator">%</span> sampleBytes <span class="operator">=</span><span class="operator">=</span> <span class="number">0</span>);
Q_UNUSED(sampleBytes) <span class="comment">// suppress warning in release builds</span>
m_buffer<span class="operator">.</span>resize(length);
<span class="type">unsigned</span> <span class="type">char</span> <span class="operator">*</span>ptr <span class="operator">=</span> <span class="keyword">reinterpret_cast</span><span class="operator"><</span><span class="type">unsigned</span> <span class="type">char</span> <span class="operator">*</span><span class="operator">></span>(m_buffer<span class="operator">.</span>data());
<span class="type">int</span> sampleIndex <span class="operator">=</span> <span class="number">0</span>;
<span class="keyword">while</span> (length) {
<span class="keyword">const</span> <span class="type">qreal</span> x <span class="operator">=</span> qSin(<span class="number">2</span> <span class="operator">*</span> M_PI <span class="operator">*</span> sampleRate <span class="operator">*</span> <span class="type">qreal</span>(sampleIndex <span class="operator">%</span> format<span class="operator">.</span>sampleRate()) <span class="operator">/</span> format<span class="operator">.</span>sampleRate());
<span class="keyword">for</span> (<span class="type">int</span> i<span class="operator">=</span><span class="number">0</span>; i<span class="operator"><</span>format<span class="operator">.</span>channelCount(); <span class="operator">+</span><span class="operator">+</span>i) {
<span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">8</span> <span class="operator">&</span><span class="operator">&</span> format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>UnSignedInt) {
<span class="keyword">const</span> <span class="type">quint8</span> value <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator"><</span><span class="type">quint8</span><span class="operator">></span>((<span class="number">1.0</span> <span class="operator">+</span> x) <span class="operator">/</span> <span class="number">2</span> <span class="operator">*</span> <span class="number">255</span>);
<span class="operator">*</span><span class="keyword">reinterpret_cast</span><span class="operator"><</span><span class="type">quint8</span><span class="operator">*</span><span class="operator">></span>(ptr) <span class="operator">=</span> value;
} <span class="keyword">else</span> <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">8</span> <span class="operator">&</span><span class="operator">&</span> format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>SignedInt) {
<span class="keyword">const</span> <span class="type">qint8</span> value <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator"><</span><span class="type">qint8</span><span class="operator">></span>(x <span class="operator">*</span> <span class="number">127</span>);
<span class="operator">*</span><span class="keyword">reinterpret_cast</span><span class="operator"><</span><span class="type">quint8</span><span class="operator">*</span><span class="operator">></span>(ptr) <span class="operator">=</span> value;
} <span class="keyword">else</span> <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">16</span> <span class="operator">&</span><span class="operator">&</span> format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>UnSignedInt) {
<span class="type">quint16</span> value <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator"><</span><span class="type">quint16</span><span class="operator">></span>((<span class="number">1.0</span> <span class="operator">+</span> x) <span class="operator">/</span> <span class="number">2</span> <span class="operator">*</span> <span class="number">65535</span>);
<span class="keyword">if</span> (format<span class="operator">.</span>byteOrder() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>LittleEndian)
qToLittleEndian<span class="operator"><</span><span class="type">quint16</span><span class="operator">></span>(value<span class="operator">,</span> ptr);
<span class="keyword">else</span>
qToBigEndian<span class="operator"><</span><span class="type">quint16</span><span class="operator">></span>(value<span class="operator">,</span> ptr);
} <span class="keyword">else</span> <span class="keyword">if</span> (format<span class="operator">.</span>sampleSize() <span class="operator">=</span><span class="operator">=</span> <span class="number">16</span> <span class="operator">&</span><span class="operator">&</span> format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>SignedInt) {
<span class="type">qint16</span> value <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator"><</span><span class="type">qint16</span><span class="operator">></span>(x <span class="operator">*</span> <span class="number">32767</span>);
<span class="keyword">if</span> (format<span class="operator">.</span>byteOrder() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>LittleEndian)
qToLittleEndian<span class="operator"><</span><span class="type">qint16</span><span class="operator">></span>(value<span class="operator">,</span> ptr);
<span class="keyword">else</span>
qToBigEndian<span class="operator"><</span><span class="type">qint16</span><span class="operator">></span>(value<span class="operator">,</span> ptr);
}
ptr <span class="operator">+</span><span class="operator">=</span> channelBytes;
length <span class="operator">-</span><span class="operator">=</span> channelBytes;
}
<span class="operator">+</span><span class="operator">+</span>sampleIndex;
}
}
<span class="type">qint64</span> Generator<span class="operator">::</span>readData(<span class="type">char</span> <span class="operator">*</span>data<span class="operator">,</span> <span class="type">qint64</span> len)
{
<span class="type">qint64</span> total <span class="operator">=</span> <span class="number">0</span>;
<span class="keyword">if</span> (<span class="operator">!</span>m_buffer<span class="operator">.</span>isEmpty()) {
<span class="keyword">while</span> (len <span class="operator">-</span> total <span class="operator">></span> <span class="number">0</span>) {
<span class="keyword">const</span> <span class="type">qint64</span> chunk <span class="operator">=</span> qMin((m_buffer<span class="operator">.</span>size() <span class="operator">-</span> m_pos)<span class="operator">,</span> len <span class="operator">-</span> total);
memcpy(data <span class="operator">+</span> total<span class="operator">,</span> m_buffer<span class="operator">.</span>constData() <span class="operator">+</span> m_pos<span class="operator">,</span> chunk);
m_pos <span class="operator">=</span> (m_pos <span class="operator">+</span> chunk) <span class="operator">%</span> m_buffer<span class="operator">.</span>size();
total <span class="operator">+</span><span class="operator">=</span> chunk;
}
}
<span class="keyword">return</span> total;
}
<span class="type">qint64</span> Generator<span class="operator">::</span>writeData(<span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>data<span class="operator">,</span> <span class="type">qint64</span> len)
{
Q_UNUSED(data);
Q_UNUSED(len);
<span class="keyword">return</span> <span class="number">0</span>;
}
<span class="type">qint64</span> Generator<span class="operator">::</span>bytesAvailable() <span class="keyword">const</span>
{
<span class="keyword">return</span> m_buffer<span class="operator">.</span>size() <span class="operator">+</span> <span class="type">QIODevice</span><span class="operator">::</span>bytesAvailable();
}
AudioTest<span class="operator">::</span>AudioTest()
: m_pushTimer(<span class="keyword">new</span> <span class="type">QTimer</span>(<span class="keyword">this</span>))
<span class="operator">,</span> m_modeButton(<span class="number">0</span>)
<span class="operator">,</span> m_suspendResumeButton(<span class="number">0</span>)
<span class="operator">,</span> m_deviceBox(<span class="number">0</span>)
<span class="operator">,</span> m_device(<span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">::</span>defaultOutputDevice())
<span class="operator">,</span> m_generator(<span class="number">0</span>)
<span class="operator">,</span> m_audioOutput(<span class="number">0</span>)
<span class="operator">,</span> m_output(<span class="number">0</span>)
<span class="operator">,</span> m_pullMode(<span class="keyword">true</span>)
<span class="operator">,</span> m_buffer(BufferSize<span class="operator">,</span> <span class="number">0</span>)
{
initializeWindow();
initializeAudio();
}
<span class="type">void</span> AudioTest<span class="operator">::</span>initializeWindow()
{
<span class="type">QScopedPointer</span><span class="operator"><</span><span class="type">QWidget</span><span class="operator">></span> window(<span class="keyword">new</span> <span class="type">QWidget</span>);
<span class="type">QScopedPointer</span><span class="operator"><</span><span class="type">QVBoxLayout</span><span class="operator">></span> layout(<span class="keyword">new</span> <span class="type">QVBoxLayout</span>);
m_deviceBox <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QComboBox</span>(<span class="keyword">this</span>);
<span class="keyword">const</span> <span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> <span class="operator">&</span>defaultDeviceInfo <span class="operator">=</span> <span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">::</span>defaultOutputDevice();
m_deviceBox<span class="operator">-</span><span class="operator">></span>addItem(defaultDeviceInfo<span class="operator">.</span>deviceName()<span class="operator">,</span> qVariantFromValue(defaultDeviceInfo));
foreach (<span class="keyword">const</span> <span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> <span class="operator">&</span>deviceInfo<span class="operator">,</span> <span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">::</span>availableDevices(<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>AudioOutput)) {
<span class="keyword">if</span> (deviceInfo <span class="operator">!</span><span class="operator">=</span> defaultDeviceInfo)
m_deviceBox<span class="operator">-</span><span class="operator">></span>addItem(deviceInfo<span class="operator">.</span>deviceName()<span class="operator">,</span> qVariantFromValue(deviceInfo));
}
connect(m_deviceBox<span class="operator">,</span>SIGNAL(activated(<span class="type">int</span>))<span class="operator">,</span>SLOT(deviceChanged(<span class="type">int</span>)));
layout<span class="operator">-</span><span class="operator">></span>addWidget(m_deviceBox);
m_modeButton <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QPushButton</span>(<span class="keyword">this</span>);
m_modeButton<span class="operator">-</span><span class="operator">></span>setText(tr(PUSH_MODE_LABEL));
connect(m_modeButton<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> SLOT(toggleMode()));
layout<span class="operator">-</span><span class="operator">></span>addWidget(m_modeButton);
m_suspendResumeButton <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QPushButton</span>(<span class="keyword">this</span>);
m_suspendResumeButton<span class="operator">-</span><span class="operator">></span>setText(tr(SUSPEND_LABEL));
connect(m_suspendResumeButton<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> SLOT(toggleSuspendResume()));
layout<span class="operator">-</span><span class="operator">></span>addWidget(m_suspendResumeButton);
<span class="type">QHBoxLayout</span> <span class="operator">*</span>volumeBox <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QHBoxLayout</span>;
m_volumeLabel <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QLabel</span>;
m_volumeLabel<span class="operator">-</span><span class="operator">></span>setText(tr(VOLUME_LABEL));
m_volumeSlider <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QSlider</span>(<span class="type">Qt</span><span class="operator">::</span>Horizontal);
m_volumeSlider<span class="operator">-</span><span class="operator">></span>setMinimum(<span class="number">0</span>);
m_volumeSlider<span class="operator">-</span><span class="operator">></span>setMaximum(<span class="number">100</span>);
m_volumeSlider<span class="operator">-</span><span class="operator">></span>setSingleStep(<span class="number">10</span>);
connect(m_volumeSlider<span class="operator">,</span> SIGNAL(valueChanged(<span class="type">int</span>))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(volumeChanged(<span class="type">int</span>)));
volumeBox<span class="operator">-</span><span class="operator">></span>addWidget(m_volumeLabel);
volumeBox<span class="operator">-</span><span class="operator">></span>addWidget(m_volumeSlider);
layout<span class="operator">-</span><span class="operator">></span>addLayout(volumeBox);
window<span class="operator">-</span><span class="operator">></span>setLayout(layout<span class="operator">.</span>data());
layout<span class="operator">.</span>take(); <span class="comment">// ownership transferred</span>
setCentralWidget(window<span class="operator">.</span>data());
<span class="type">QWidget</span> <span class="operator">*</span><span class="keyword">const</span> windowPtr <span class="operator">=</span> window<span class="operator">.</span>take(); <span class="comment">// ownership transferred</span>
windowPtr<span class="operator">-</span><span class="operator">></span>show();
}
<span class="type">void</span> AudioTest<span class="operator">::</span>initializeAudio()
{
connect(m_pushTimer<span class="operator">,</span> SIGNAL(timeout())<span class="operator">,</span> SLOT(pushTimerExpired()));
m_format<span class="operator">.</span>setSampleRate(DataSampleRateHz);
m_format<span class="operator">.</span>setChannelCount(<span class="number">1</span>);
m_format<span class="operator">.</span>setSampleSize(<span class="number">16</span>);
m_format<span class="operator">.</span>setCodec(<span class="string">"audio/pcm"</span>);
m_format<span class="operator">.</span>setByteOrder(<span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>LittleEndian);
m_format<span class="operator">.</span>setSampleType(<span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>SignedInt);
<span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> info(m_device);
<span class="keyword">if</span> (<span class="operator">!</span>info<span class="operator">.</span>isFormatSupported(m_format)) {
qWarning() <span class="operator"><</span><span class="operator"><</span> <span class="string">"Default format not supported - trying to use nearest"</span>;
m_format <span class="operator">=</span> info<span class="operator">.</span>nearestFormat(m_format);
}
<span class="keyword">if</span> (m_generator)
<span class="keyword">delete</span> m_generator;
m_generator <span class="operator">=</span> <span class="keyword">new</span> Generator(m_format<span class="operator">,</span> DurationSeconds<span class="operator">*</span><span class="number">1000000</span><span class="operator">,</span> ToneSampleRateHz<span class="operator">,</span> <span class="keyword">this</span>);
createAudioOutput();
}
<span class="type">void</span> AudioTest<span class="operator">::</span>createAudioOutput()
{
<span class="keyword">delete</span> m_audioOutput;
m_audioOutput <span class="operator">=</span> <span class="number">0</span>;
m_audioOutput <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaudiooutput.html">QAudioOutput</a></span>(m_device<span class="operator">,</span> m_format<span class="operator">,</span> <span class="keyword">this</span>);
m_generator<span class="operator">-</span><span class="operator">></span>start();
m_audioOutput<span class="operator">-</span><span class="operator">></span>start(m_generator);
<span class="type">qreal</span> initialVolume <span class="operator">=</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>convertVolume(m_audioOutput<span class="operator">-</span><span class="operator">></span>volume()<span class="operator">,</span>
<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>LinearVolumeScale<span class="operator">,</span>
<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>LogarithmicVolumeScale);
m_volumeSlider<span class="operator">-</span><span class="operator">></span>setValue(qRound(initialVolume <span class="operator">*</span> <span class="number">100</span>));
}
AudioTest<span class="operator">::</span><span class="operator">~</span>AudioTest()
{
}
<span class="type">void</span> AudioTest<span class="operator">::</span>deviceChanged(<span class="type">int</span> index)
{
m_pushTimer<span class="operator">-</span><span class="operator">></span>stop();
m_generator<span class="operator">-</span><span class="operator">></span>stop();
m_audioOutput<span class="operator">-</span><span class="operator">></span>stop();
m_audioOutput<span class="operator">-</span><span class="operator">></span>disconnect(<span class="keyword">this</span>);
m_device <span class="operator">=</span> m_deviceBox<span class="operator">-</span><span class="operator">></span>itemData(index)<span class="operator">.</span>value<span class="operator"><</span><span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">></span>();
initializeAudio();
}
<span class="type">void</span> AudioTest<span class="operator">::</span>volumeChanged(<span class="type">int</span> value)
{
<span class="keyword">if</span> (m_audioOutput) {
<span class="type">qreal</span> linearVolume <span class="operator">=</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>convertVolume(value <span class="operator">/</span> <span class="type">qreal</span>(<span class="number">100</span>)<span class="operator">,</span>
<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>LogarithmicVolumeScale<span class="operator">,</span>
<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>LinearVolumeScale);
m_audioOutput<span class="operator">-</span><span class="operator">></span>setVolume(linearVolume);
}
}
<span class="type">void</span> AudioTest<span class="operator">::</span>pushTimerExpired()
{
<span class="keyword">if</span> (m_audioOutput <span class="operator">&</span><span class="operator">&</span> m_audioOutput<span class="operator">-</span><span class="operator">></span>state() <span class="operator">!</span><span class="operator">=</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>StoppedState) {
<span class="type">int</span> chunks <span class="operator">=</span> m_audioOutput<span class="operator">-</span><span class="operator">></span>bytesFree()<span class="operator">/</span>m_audioOutput<span class="operator">-</span><span class="operator">></span>periodSize();
<span class="keyword">while</span> (chunks) {
<span class="keyword">const</span> <span class="type">qint64</span> len <span class="operator">=</span> m_generator<span class="operator">-</span><span class="operator">></span>read(m_buffer<span class="operator">.</span>data()<span class="operator">,</span> m_audioOutput<span class="operator">-</span><span class="operator">></span>periodSize());
<span class="keyword">if</span> (len)
m_output<span class="operator">-</span><span class="operator">></span>write(m_buffer<span class="operator">.</span>data()<span class="operator">,</span> len);
<span class="keyword">if</span> (len <span class="operator">!</span><span class="operator">=</span> m_audioOutput<span class="operator">-</span><span class="operator">></span>periodSize())
<span class="keyword">break</span>;
<span class="operator">-</span><span class="operator">-</span>chunks;
}
}
}
<span class="type">void</span> AudioTest<span class="operator">::</span>toggleMode()
{
m_pushTimer<span class="operator">-</span><span class="operator">></span>stop();
m_audioOutput<span class="operator">-</span><span class="operator">></span>stop();
<span class="keyword">if</span> (m_pullMode) {
<span class="comment">//switch to push mode (periodically push to QAudioOutput using a timer)</span>
m_modeButton<span class="operator">-</span><span class="operator">></span>setText(tr(PULL_MODE_LABEL));
m_output <span class="operator">=</span> m_audioOutput<span class="operator">-</span><span class="operator">></span>start();
m_pullMode <span class="operator">=</span> <span class="keyword">false</span>;
m_pushTimer<span class="operator">-</span><span class="operator">></span>start(<span class="number">20</span>);
} <span class="keyword">else</span> {
<span class="comment">//switch to pull mode (QAudioOutput pulls from Generator as needed)</span>
m_modeButton<span class="operator">-</span><span class="operator">></span>setText(tr(PUSH_MODE_LABEL));
m_pullMode <span class="operator">=</span> <span class="keyword">true</span>;
m_audioOutput<span class="operator">-</span><span class="operator">></span>start(m_generator);
}
m_suspendResumeButton<span class="operator">-</span><span class="operator">></span>setText(tr(SUSPEND_LABEL));
}
<span class="type">void</span> AudioTest<span class="operator">::</span>toggleSuspendResume()
{
<span class="keyword">if</span> (m_audioOutput<span class="operator">-</span><span class="operator">></span>state() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>SuspendedState) {
m_audioOutput<span class="operator">-</span><span class="operator">></span>resume();
m_suspendResumeButton<span class="operator">-</span><span class="operator">></span>setText(tr(SUSPEND_LABEL));
} <span class="keyword">else</span> <span class="keyword">if</span> (m_audioOutput<span class="operator">-</span><span class="operator">></span>state() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>ActiveState) {
m_audioOutput<span class="operator">-</span><span class="operator">></span>suspend();
m_suspendResumeButton<span class="operator">-</span><span class="operator">></span>setText(tr(RESUME_LABEL));
} <span class="keyword">else</span> <span class="keyword">if</span> (m_audioOutput<span class="operator">-</span><span class="operator">></span>state() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>StoppedState) {
m_audioOutput<span class="operator">-</span><span class="operator">></span>resume();
m_suspendResumeButton<span class="operator">-</span><span class="operator">></span>setText(tr(SUSPEND_LABEL));
} <span class="keyword">else</span> <span class="keyword">if</span> (m_audioOutput<span class="operator">-</span><span class="operator">></span>state() <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>IdleState) {
<span class="comment">// no-op</span>
}
}
</pre>
</div>
<!-- @@@multimedia/audiooutput/audiooutput.cpp -->
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<acronym title="Copyright">©</acronym> 2017 The Qt Company Ltd.
Documentation contributions included herein are the copyrights of
their respective owners.<br> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property
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