<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>audiooutput.cpp Example File | Qt Multimedia 5.12.2</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qtmultimedia-index.html">Qt Multimedia</a></td><td ><a href="qtmultimedia-multimedia-audiooutput-example.html">Audio Output Example</a></td><td >audiooutput.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtmultimedia-index.html">Qt 5.12.2 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"><div class="sidebar-content" id="sidebar-content"></div></div> <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 "audiooutput.h"</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> Generator<span class="operator">::</span>Generator(<span class="keyword">const</span> <span class="type">QAudioFormat</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">if</span> (format<span class="operator">.</span>isValid()) generateData(format<span class="operator">,</span> durationUs<span class="operator">,</span> sampleRate); } <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">QAudioFormat</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">1000000</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="comment">// Produces value (-1..1)</span> <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><span class="operator">+</span> <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="keyword">if</span> (format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type">QAudioFormat</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>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type">QAudioFormat</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">qint8</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="keyword">if</span> (format<span class="operator">.</span>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type">QAudioFormat</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">QAudioFormat</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>sampleType() <span class="operator">=</span><span class="operator">=</span> <span class="type">QAudioFormat</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">QAudioFormat</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="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>)) { initializeWindow(); initializeAudio(<span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">::</span>defaultOutputDevice()); } AudioTest<span class="operator">::</span><span class="operator">~</span>AudioTest() { m_pushTimer<span class="operator">-</span><span class="operator">></span>stop(); } <span class="type">void</span> AudioTest<span class="operator">::</span>initializeWindow() { <span class="type">QWidget</span> <span class="operator">*</span>window <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QWidget</span>; <span class="type">QVBoxLayout</span> <span class="operator">*</span>layout <span class="operator">=</span> <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)); <span class="keyword">for</span> (<span class="keyword">auto</span> <span class="operator">&</span>deviceInfo: <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> <span class="type">QOverload</span><span class="operator"><</span><span class="type">int</span><span class="operator">></span><span class="operator">::</span>of(<span class="operator">&</span><span class="type">QComboBox</span><span class="operator">::</span>activated)<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>AudioTest<span class="operator">::</span>deviceChanged); 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>); connect(m_modeButton<span class="operator">,</span> <span class="operator">&</span><span class="type">QPushButton</span><span class="operator">::</span>clicked<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>AudioTest<span class="operator">::</span>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>); connect(m_suspendResumeButton<span class="operator">,</span> <span class="operator">&</span><span class="type">QPushButton</span><span class="operator">::</span>clicked<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>AudioTest<span class="operator">::</span>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(<span class="string">"Volume:"</span>)); 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> <span class="operator">&</span><span class="type">QSlider</span><span class="operator">::</span>valueChanged<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&</span>AudioTest<span class="operator">::</span>volumeChanged); 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); setCentralWidget(window); window<span class="operator">-</span><span class="operator">></span>show(); } <span class="type">void</span> AudioTest<span class="operator">::</span>initializeAudio(<span class="keyword">const</span> <span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> <span class="operator">&</span>deviceInfo) { <span class="type">QAudioFormat</span> format; format<span class="operator">.</span>setSampleRate(<span class="number">44100</span>); format<span class="operator">.</span>setChannelCount(<span class="number">1</span>); format<span class="operator">.</span>setSampleSize(<span class="number">16</span>); format<span class="operator">.</span>setCodec(<span class="string">"audio/pcm"</span>); format<span class="operator">.</span>setByteOrder(<span class="type">QAudioFormat</span><span class="operator">::</span>LittleEndian); format<span class="operator">.</span>setSampleType(<span class="type">QAudioFormat</span><span class="operator">::</span>SignedInt); <span class="keyword">if</span> (<span class="operator">!</span>deviceInfo<span class="operator">.</span>isFormatSupported(format)) { qWarning() <span class="operator"><</span><span class="operator"><</span> <span class="string">"Default format not supported - trying to use nearest"</span>; format <span class="operator">=</span> deviceInfo<span class="operator">.</span>nearestFormat(format); } <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>; m_generator<span class="operator">.</span>reset(<span class="keyword">new</span> Generator(format<span class="operator">,</span> durationSeconds <span class="operator">*</span> <span class="number">1000000</span><span class="operator">,</span> toneSampleRateHz)); m_audioOutput<span class="operator">.</span>reset(<span class="keyword">new</span> <span class="type"><a href="qaudiooutput.html">QAudioOutput</a></span>(deviceInfo<span class="operator">,</span> format)); m_generator<span class="operator">-</span><span class="operator">></span>start(); <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>)); toggleMode(); } <span class="type">void</span> AudioTest<span class="operator">::</span>deviceChanged(<span class="type">int</span> index) { 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>); initializeAudio(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>()); } <span class="type">void</span> AudioTest<span class="operator">::</span>volumeChanged(<span class="type">int</span> value) { <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>toggleMode() { m_pushTimer<span class="operator">-</span><span class="operator">></span>stop(); m_audioOutput<span class="operator">-</span><span class="operator">></span>stop(); toggleSuspendResume(); <span class="keyword">if</span> (m_pullMode) { <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(<span class="string">"Enable push mode"</span>)); m_audioOutput<span class="operator">-</span><span class="operator">></span>start(m_generator<span class="operator">.</span>data()); } <span class="keyword">else</span> { <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(<span class="string">"Enable pull mode"</span>)); <span class="keyword">auto</span> io <span class="operator">=</span> m_audioOutput<span class="operator">-</span><span class="operator">></span>start(); m_pushTimer<span class="operator">-</span><span class="operator">></span>disconnect(); connect(m_pushTimer<span class="operator">,</span> <span class="operator">&</span><span class="type">QTimer</span><span class="operator">::</span>timeout<span class="operator">,</span> <span class="operator">[</span><span class="keyword">this</span><span class="operator">,</span> io<span class="operator">]</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) <span class="keyword">return</span>; <span class="type">QByteArray</span> buffer(<span class="number">32768</span><span class="operator">,</span> <span class="number">0</span>); <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(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) io<span class="operator">-</span><span class="operator">></span>write(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; } }); m_pushTimer<span class="operator">-</span><span class="operator">></span>start(<span class="number">20</span>); } m_pullMode <span class="operator">=</span> <span class="operator">!</span>m_pullMode; } <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 <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) { m_audioOutput<span class="operator">-</span><span class="operator">></span>resume(); m_suspendResumeButton<span class="operator">-</span><span class="operator">></span>setText(tr(<span class="string">"Suspend recording"</span>)); } <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(<span class="string">"Resume playback"</span>)); } <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 --> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 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 of their respective owners. </p> </div> </body> </html>