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<td >Qt 5.12</td><td ><a href="qtmultimedia-index.html">Qt Multimedia</a></td><td ><a href="multimedia-examples.html">Qt Multimedia Examples</a></td><td >Audio Recorder Example</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>
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<h3><a name="toc">Contents</a></h3>
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<li class="level1"><a href="#running-the-example">Running the Example</a></li>
<li class="level1"><a href="#displaying-the-window-and-audio-settings">Displaying the Window and Audio Settings</a></li>
<li class="level1"><a href="#recording-audio">Recording Audio</a></li>
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<h1 class="title">Audio Recorder Example</h1>
<span class="subtitle"></span>
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<p>Discovering the available devices and supported codecs.</p>
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<div class="descr"> <a name="details"></a>
<p><i>Audio Recorder</i> demonstrates how to identify the available devices and supported codecs, and the use of <a href="qaudiorecorder.html">QAudioRecorder</a> class.</p>
<p class="centerAlign"><img src="images/audiorecorder.png" alt="" /></p><a name="running-the-example"></a>
<h2 id="running-the-example">Running the Example</h2>
<p>To run the example from Qt Creator, open the <b>Welcome</b> mode and select the example from <b>Examples</b>. For more information, visit Building and Running an Example.</p>
<a name="displaying-the-window-and-audio-settings"></a>
<h2 id="displaying-the-window-and-audio-settings">Displaying the Window and Audio Settings</h2>
<p>We display a window for the user to select the appropriate audio input, codec, container, and sample rate. Allow a setting of either quality or bitrate. Finally, the output file can be selected and recording can be started.</p>
<p>The lists are setup using the <a href="qaudiorecorder.html#audioInputs">audioInputs()</a>, <a href="qmediarecorder.html#supportedAudioCodecs">supportedAudioCodecs()</a>, <a href="qmediarecorder.html#supportedContainers">supportedContainers()</a>, <a href="qmediarecorder.html#supportedContainers">supportedContainers()</a>, and <a href="qmediarecorder.html#supportedAudioSampleRates">supportedAudioSampleRates()</a> methods. The quality slider is setup from 0 (zero) to <a href="qmultimedia.html#EncodingQuality-enum">QMultimedia::VeryHighQuality</a> with a default value of <a href="qmultimedia.html#EncodingQuality-enum">QMultimedia::NormalQuality</a>, while the bitrates are hardcoded into the list.</p>
<a name="recording-audio"></a>
<h2 id="recording-audio">Recording Audio</h2>
<p>To record audio we simply create a <a href="qaudiorecorder.html">QAudioRecorder</a> object.</p>
<pre class="cpp">
audioRecorder <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaudiorecorder.html">QAudioRecorder</a></span>(<span class="keyword">this</span>);
</pre>
<p>And setup the lists as described above. The text on the record and pause buttons are toggled depending on the <a href="qmediarecorder.html#State-enum">state</a> of the <code>audioRecorder</code> object. This means that if the state is <a href="qmediarecorder.html#State-enum">QMediaRecorder::StoppedState</a> then the button text will be "Record" and "Pause". In <a href="qmediarecorder.html#State-enum">QMediaRecorder::RecordingState</a> the record button will have the text "Stop", and in <a href="qmediarecorder.html#State-enum">QMediaRecorder::PausedState</a> the pause button will have the text "Resume".</p>
<p>Pressing the buttons will also result in a toggle based on the state. If recording is stopped, then pressing the record button will setup the <a href="qaudioencodersettings.html">QAudioEncoderSettings</a> based on the values of the selection lists, will set the encoding settings and container on the <code>audioRecorder</code> object, and start recording using the <a href="qmediarecorder.html#record">record()</a> method.</p>
<pre class="cpp">
<span class="type"><a href="qaudioencodersettings.html">QAudioEncoderSettings</a></span> settings;
settings<span class="operator">.</span>setCodec(boxValue(ui<span class="operator">-</span><span class="operator">></span>audioCodecBox)<span class="operator">.</span>toString());
settings<span class="operator">.</span>setSampleRate(boxValue(ui<span class="operator">-</span><span class="operator">></span>sampleRateBox)<span class="operator">.</span>toInt());
settings<span class="operator">.</span>setBitRate(boxValue(ui<span class="operator">-</span><span class="operator">></span>bitrateBox)<span class="operator">.</span>toInt());
settings<span class="operator">.</span>setQuality(<span class="type"><a href="qmultimedia.html">QMultimedia</a></span><span class="operator">::</span>EncodingQuality(ui<span class="operator">-</span><span class="operator">></span>qualitySlider<span class="operator">-</span><span class="operator">></span>value()));
settings<span class="operator">.</span>setEncodingMode(ui<span class="operator">-</span><span class="operator">></span>constantQualityRadioButton<span class="operator">-</span><span class="operator">></span>isChecked() <span class="operator">?</span>
<span class="type"><a href="qmultimedia.html">QMultimedia</a></span><span class="operator">::</span>ConstantQualityEncoding :
<span class="type"><a href="qmultimedia.html">QMultimedia</a></span><span class="operator">::</span>ConstantBitRateEncoding);
<span class="type">QString</span> container <span class="operator">=</span> boxValue(ui<span class="operator">-</span><span class="operator">></span>containerBox)<span class="operator">.</span>toString();
audioRecorder<span class="operator">-</span><span class="operator">></span>setEncodingSettings(settings<span class="operator">,</span> <span class="type"><a href="qvideoencodersettings.html">QVideoEncoderSettings</a></span>()<span class="operator">,</span> container);
audioRecorder<span class="operator">-</span><span class="operator">></span>record();
</pre>
<p>While recording, the status bar of the application is updated with duration information from the <a href="qmediarecorder.html#durationChanged">durationChanged</a> signal from the <code>audioRecorder</code> object.</p>
<pre class="cpp">
ui<span class="operator">-</span><span class="operator">></span>statusbar<span class="operator">-</span><span class="operator">></span>showMessage(tr(<span class="string">"Recorded %1 sec"</span>)<span class="operator">.</span>arg(duration <span class="operator">/</span> <span class="number">1000</span>));
</pre>
<p>Files:</p>
<ul>
<li><a href="qtmultimedia-multimedia-audiorecorder-audiolevel-cpp.html">multimedia/audiorecorder/audiolevel.cpp</a></li>
<li><a href="qtmultimedia-multimedia-audiorecorder-audiolevel-h.html">multimedia/audiorecorder/audiolevel.h</a></li>
<li><a href="qtmultimedia-multimedia-audiorecorder-audiorecorder-cpp.html">multimedia/audiorecorder/audiorecorder.cpp</a></li>
<li><a href="qtmultimedia-multimedia-audiorecorder-audiorecorder-h.html">multimedia/audiorecorder/audiorecorder.h</a></li>
<li><a href="qtmultimedia-multimedia-audiorecorder-audiorecorder-pro.html">multimedia/audiorecorder/audiorecorder.pro</a></li>
<li><a href="qtmultimedia-multimedia-audiorecorder-audiorecorder-ui.html">multimedia/audiorecorder/audiorecorder.ui</a></li>
<li><a href="qtmultimedia-multimedia-audiorecorder-main-cpp.html">multimedia/audiorecorder/main.cpp</a></li>
</ul>
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