<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- qaudiosystemplugin.cpp --> <title>QAudioSystemPlugin Class | Qt Multimedia 5.12.6</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-modules.html">C++ Classes</a></td><td >QAudioSystemPlugin</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtmultimedia-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#public-functions">Public Functions</a></li> <li class="level1"><a href="#reimplemented-public-functions">Reimplemented Public Functions</a></li> <li class="level1"><a href="#static-public-members">Static Public Members</a></li> <li class="level1"><a href="#details">Detailed Description</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">QAudioSystemPlugin Class</h1> <!-- $$$QAudioSystemPlugin-brief --> <p>The <a href="qaudiosystemplugin.html">QAudioSystemPlugin</a> class provides an abstract base for audio plugins. <a href="#details">More...</a></p> <!-- @@@QAudioSystemPlugin --> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QAudioSystemPlugin></span> </td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += multimedia</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherits:</td><td class="memItemRight bottomAlign"> QAudioSystemFactoryInterface and </td></tr></table></div><ul> <li><a href="qaudiosystemplugin-members.html">List of all members, including inherited members</a></li> </ul> <a name="public-functions"></a> <h2 id="public-functions">Public Functions</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qaudiosystemplugin.html#QAudioSystemPlugin">QAudioSystemPlugin</a></b>(QObject *<i>parent</i> = nullptr)</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual </td><td class="memItemRight bottomAlign"><b><a href="qaudiosystemplugin.html#dtor.QAudioSystemPlugin">~QAudioSystemPlugin</a></b>()</td></tr> </table></div> <a name="reimplemented-public-functions"></a> <h2 id="reimplemented-public-functions">Reimplemented Public Functions</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> virtual QList<QByteArray> </td><td class="memItemRight bottomAlign"><b><a href="qaudiosystemplugin.html#availableDevices">availableDevices</a></b>(QAudio::Mode <i>mode</i>) const override = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual QAbstractAudioDeviceInfo *</td><td class="memItemRight bottomAlign"><b><a href="qaudiosystemplugin.html#createDeviceInfo">createDeviceInfo</a></b>(const QByteArray &<i>device</i>, QAudio::Mode <i>mode</i>) override = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual QAbstractAudioInput *</td><td class="memItemRight bottomAlign"><b><a href="qaudiosystemplugin.html#createInput">createInput</a></b>(const QByteArray &<i>device</i>) override = 0</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> virtual QAbstractAudioOutput *</td><td class="memItemRight bottomAlign"><b><a href="qaudiosystemplugin.html#createOutput">createOutput</a></b>(const QByteArray &<i>device</i>) override = 0</td></tr> </table></div> <a name="static-public-members"></a> <h2 id="static-public-members">Static Public Members</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> const QMetaObject </td><td class="memItemRight bottomAlign"><b><a href="qaudiosystemplugin.html#staticMetaObject-var">staticMetaObject</a></b></td></tr> </table></div> <a name="details"></a> <!-- $$$QAudioSystemPlugin-description --> <div class="descr"> <h2 id="details">Detailed Description</h2> <p>The <a href="qaudiosystemplugin.html">QAudioSystemPlugin</a> class provides an abstract base for audio plugins.</p> <p>Writing a audio plugin is achieved by subclassing this base class, reimplementing the pure virtual functions <a href="qaudiosystemplugin.html#availableDevices">availableDevices</a>(), <a href="qaudiosystemplugin.html#createInput">createInput</a>(), <a href="qaudiosystemplugin.html#createOutput">createOutput</a>() and <a href="qaudiosystemplugin.html#createDeviceInfo">createDeviceInfo</a>() then exporting the class with the Q_PLUGIN_METADATA() macro.</p> <p>The json file containing the meta data should contain a list of keys matching the plugin. Add "default" to your list of keys available to override the default audio device to be provided by your plugin.</p> <pre class="cpp"> { <span class="string">"Keys"</span>: <span class="operator">[</span> <span class="string">"default"</span> <span class="operator">]</span> } </pre> <p>Unit tests are available to help in debugging new plugins.</p> <p>Qt comes with plugins for Windows (WinMM and WASAPI), Linux (ALSA and PulseAudio), macOS / iOS (CoreAudio), Android (OpenSL ES) and QNX.</p> <p>If no audio plugins are available, a fallback dummy backend will be used. This should print out warnings if this is the case when you try and use <a href="qaudioinput.html">QAudioInput</a> or <a href="qaudiooutput.html">QAudioOutput</a>. To fix this problem, make sure the dependencies for the Qt plugins are installed on the system and reconfigure Qt (e.g. alsa-devel package on Linux), or create your own plugin with a default key to always override the dummy fallback. The easiest way to determine if you have only a dummy backend is to get a list of available audio devices.</p> <p><a href="qaudiodeviceinfo.html#availableDevices">QAudioDeviceInfo::availableDevices</a>(<a href="qaudio.html#Mode-enum">QAudio::AudioOutput</a>).size() = 0 (dummy backend)</p> </div> <p><b>See also </b><a href="qabstractaudiodeviceinfo.html">QAbstractAudioDeviceInfo</a>, <a href="qabstractaudiooutput.html">QAbstractAudioOutput</a>, and <a href="qabstractaudioinput.html">QAbstractAudioInput</a>.</p> <!-- @@@QAudioSystemPlugin --> <div class="func"> <h2>Member Function Documentation</h2> <!-- $$$QAudioSystemPlugin[overload1]$$$QAudioSystemPluginQObject* --> <h3 class="fn" id="QAudioSystemPlugin"><a name="QAudioSystemPlugin"></a>QAudioSystemPlugin::<span class="name">QAudioSystemPlugin</span>(<span class="type">QObject</span> *<i>parent</i> = nullptr)</h3> <p>Constructs a new audio plugin with <i>parent</i>. This is invoked automatically by the Q_PLUGIN_METADATA() macro.</p> <!-- @@@QAudioSystemPlugin --> <!-- $$$~QAudioSystemPlugin[overload1]$$$~QAudioSystemPlugin --> <h3 class="fn" id="dtor.QAudioSystemPlugin"><a name="dtor.QAudioSystemPlugin"></a><code>[virtual] </code>QAudioSystemPlugin::<span class="name">~QAudioSystemPlugin</span>()</h3> <p>Destroys the audio plugin. You never have to call this explicitly. Qt destroys a plugin automatically when it is no longer used.</p> <!-- @@@~QAudioSystemPlugin --> <!-- $$$availableDevices[overload1]$$$availableDevicesQAudio::Mode --> <h3 class="fn" id="availableDevices"><a name="availableDevices"></a><code>[override pure virtual] </code><span class="type">QList</span><<span class="type">QByteArray</span>> QAudioSystemPlugin::<span class="name">availableDevices</span>(<span class="type"><a href="qaudio.html#Mode-enum">QAudio::Mode</a></span> <i>mode</i>) const</h3> <p>Returns a list of available audio devices for <i>mode</i></p> <!-- @@@availableDevices --> <!-- $$$createDeviceInfo[overload1]$$$createDeviceInfoconstQByteArray&QAudio::Mode --> <h3 class="fn" id="createDeviceInfo"><a name="createDeviceInfo"></a><code>[override pure virtual] </code><span class="type"><a href="qabstractaudiodeviceinfo.html">QAbstractAudioDeviceInfo</a></span> *QAudioSystemPlugin::<span class="name">createDeviceInfo</span>(const <span class="type">QByteArray</span> &<i>device</i>, <span class="type"><a href="qaudio.html#Mode-enum">QAudio::Mode</a></span> <i>mode</i>)</h3> <p>Returns a pointer to a <a href="qabstractaudiodeviceinfo.html">QAbstractAudioDeviceInfo</a> created using <i>device</i> and <i>mode</i></p> <!-- @@@createDeviceInfo --> <!-- $$$createInput[overload1]$$$createInputconstQByteArray& --> <h3 class="fn" id="createInput"><a name="createInput"></a><code>[override pure virtual] </code><span class="type"><a href="qabstractaudioinput.html">QAbstractAudioInput</a></span> *QAudioSystemPlugin::<span class="name">createInput</span>(const <span class="type">QByteArray</span> &<i>device</i>)</h3> <p>Returns a pointer to a <a href="qabstractaudioinput.html">QAbstractAudioInput</a> created using <i>device</i> identifier</p> <!-- @@@createInput --> <!-- $$$createOutput[overload1]$$$createOutputconstQByteArray& --> <h3 class="fn" id="createOutput"><a name="createOutput"></a><code>[override pure virtual] </code><span class="type"><a href="qabstractaudiooutput.html">QAbstractAudioOutput</a></span> *QAudioSystemPlugin::<span class="name">createOutput</span>(const <span class="type">QByteArray</span> &<i>device</i>)</h3> <p>Returns a pointer to a <a href="qabstractaudiooutput.html">QAbstractAudioOutput</a> created using <i>device</i> identifier</p> <!-- @@@createOutput --> </div> </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>