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<td >Qt 5.9</td><td ><a href="qtmultimedia-index.html">Qt Multimedia</a></td><td ><a href="qtmultimedia-modules.html">C++ Classes</a></td><td >QAudioInput</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right">Qt 5.9.4 Reference Documentation</td>
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<h3><a name="toc">Contents</a></h3>
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<li class="level1"><a href="#public-functions">Public Functions</a></li>
<li class="level1"><a href="#signals">Signals</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
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<h1 class="title">QAudioInput Class</h1>
<!-- $$$QAudioInput-brief -->
<p>The <a href="qaudioinput.html">QAudioInput</a> class provides an interface for receiving audio data from an audio input device. <a href="#details">More...</a></p>
<!-- @@@QAudioInput -->
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QAudioInput></span>
</td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += multimedia</td></tr></table></div><ul>
<li><a href="qaudioinput-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="qaudioinput.html#QAudioInput">QAudioInput</a></b>(const QAudioFormat &<i>format</i> = QAudioFormat(), QObject *<i>parent</i> = Q_NULLPTR)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#QAudioInput-1">QAudioInput</a></b>(const QAudioDeviceInfo &<i>audioDevice</i>, const QAudioFormat &<i>format</i> = QAudioFormat(), QObject *<i>parent</i> = Q_NULLPTR)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#dtor.QAudioInput">~QAudioInput</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#bufferSize">bufferSize</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#bytesReady">bytesReady</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> qint64 </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#elapsedUSecs">elapsedUSecs</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QAudio::Error </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#error">error</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QAudioFormat </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#format">format</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#notifyInterval">notifyInterval</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#periodSize">periodSize</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> qint64 </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#processedUSecs">processedUSecs</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#reset">reset</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#resume">resume</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#setBufferSize">setBufferSize</a></b>(int <i>value</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#setNotifyInterval">setNotifyInterval</a></b>(int <i>ms</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#setVolume">setVolume</a></b>(qreal <i>volume</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#start">start</a></b>(QIODevice *<i>device</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QIODevice *</td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#start-1">start</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QAudio::State </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#state">state</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#stop">stop</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#suspend">suspend</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> qreal </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#volume">volume</a></b>() const</td></tr>
</table></div>
<a name="signals"></a>
<h2 id="signals">Signals</h2>
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#notify">notify</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qaudioinput.html#stateChanged">stateChanged</a></b>(QAudio::State <i>state</i>)</td></tr>
</table></div>
<a name="details"></a>
<!-- $$$QAudioInput-description -->
<div class="descr">
<h2 id="details">Detailed Description</h2>
<p>The <a href="qaudioinput.html">QAudioInput</a> class provides an interface for receiving audio data from an audio input device.</p>
<p>You can construct an audio input with the system's <a href="qaudiodeviceinfo.html#defaultInputDevice">default audio input device</a>. It is also possible to create <a href="qaudioinput.html">QAudioInput</a> with a specific <a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a>. When you create the audio input, you should also send in the <a href="qaudioformat.html">QAudioFormat</a> to be used for the recording (see the <a href="qaudioformat.html">QAudioFormat</a> class description for details).</p>
<p>To record to a file:</p>
<p><a href="qaudioinput.html">QAudioInput</a> lets you record audio with an audio input device. The default constructor of this class will use the systems default audio device, but you can also specify a <a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a> for a specific device. You also need to pass in the <a href="qaudioformat.html">QAudioFormat</a> in which you wish to record.</p>
<p>Starting up the <a href="qaudioinput.html">QAudioInput</a> is simply a matter of calling <a href="qaudioinput.html#start-1">start</a>() with a QIODevice opened for writing. For instance, to record to a file, you can:</p>
<pre class="cpp">
<span class="type">QFile</span> destinationFile; <span class="comment">// Class member</span>
<span class="type"><a href="qaudioinput.html#QAudioInput">QAudioInput</a></span><span class="operator">*</span> audio; <span class="comment">// Class member</span>
{
destinationFile<span class="operator">.</span>setFileName(<span class="string">"/tmp/test.raw"</span>);
destinationFile<span class="operator">.</span>open( <span class="type">QIODevice</span><span class="operator">::</span>WriteOnly <span class="operator">|</span> <span class="type">QIODevice</span><span class="operator">::</span>Truncate );
<span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> format;
<span class="comment">// Set up the desired format, for example:</span>
format<span class="operator">.</span>setSampleRate(<span class="number">8000</span>);
format<span class="operator">.</span>setChannelCount(<span class="number">1</span>);
format<span class="operator">.</span>setSampleSize(<span class="number">8</span>);
format<span class="operator">.</span>setCodec(<span class="string">"audio/pcm"</span>);
format<span class="operator">.</span>setByteOrder(<span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>LittleEndian);
format<span class="operator">.</span>setSampleType(<span class="type"><a href="qaudioformat.html">QAudioFormat</a></span><span class="operator">::</span>UnSignedInt);
<span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> info <span class="operator">=</span> <span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span><span class="operator">::</span>defaultInputDevice();
<span class="keyword">if</span> (<span class="operator">!</span>info<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 the nearest."</span>;
format <span class="operator">=</span> info<span class="operator">.</span>nearestFormat(format);
}
audio <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qaudioinput.html#QAudioInput">QAudioInput</a></span>(format<span class="operator">,</span> <span class="keyword">this</span>);
connect(audio<span class="operator">,</span> SIGNAL(stateChanged(<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>State))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(handleStateChanged(<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>State)));
<span class="type">QTimer</span><span class="operator">::</span>singleShot(<span class="number">3000</span><span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(stopRecording()));
audio<span class="operator">-</span><span class="operator">></span>start(<span class="operator">&</span>destinationFile);
<span class="comment">// Records audio for 3000ms</span>
}
</pre>
<p>This will start recording if the format specified is supported by the input device (you can check this with <a href="qaudiodeviceinfo.html#isFormatSupported">QAudioDeviceInfo::isFormatSupported</a>(). In case there are any snags, use the <a href="qaudioinput.html#error">error</a>() function to check what went wrong. We stop recording in the <code>stopRecording()</code> slot.</p>
<pre class="cpp">
<span class="type">void</span> AudioInputExample<span class="operator">::</span>stopRecording()
{
audio<span class="operator">-</span><span class="operator">></span>stop();
destinationFile<span class="operator">.</span>close();
<span class="keyword">delete</span> audio;
}
</pre>
<p>At any point in time, <a href="qaudioinput.html">QAudioInput</a> will be in one of four states: active, suspended, stopped, or idle. These states are specified by the <a href="qaudio.html#State-enum">QAudio::State</a> enum. You can request a state change directly through <a href="qaudioinput.html#suspend">suspend</a>(), <a href="qaudioinput.html#resume">resume</a>(), <a href="qaudioinput.html#stop">stop</a>(), <a href="qaudioinput.html#reset">reset</a>(), and <a href="qaudioinput.html#start-1">start</a>(). The current state is reported by <a href="qaudioinput.html#state">state</a>(). <a href="qaudiooutput.html">QAudioOutput</a> will also signal you when the state changes (<a href="qaudioinput.html#stateChanged">stateChanged</a>()).</p>
<p><a href="qaudioinput.html">QAudioInput</a> provides several ways of measuring the time that has passed since the <a href="qaudioinput.html#start-1">start</a>() of the recording. The <code>processedUSecs()</code> function returns the length of the stream in microseconds written, i.e., it leaves out the times the audio input was suspended or idle. The <a href="qaudioinput.html#elapsedUSecs">elapsedUSecs</a>() function returns the time elapsed since <a href="qaudioinput.html#start-1">start</a>() was called regardless of which states the <a href="qaudioinput.html">QAudioInput</a> has been in.</p>
<p>If an error should occur, you can fetch its reason with <a href="qaudioinput.html#error">error</a>(). The possible error reasons are described by the <a href="qaudio.html#Error-enum">QAudio::Error</a> enum. The <a href="qaudioinput.html">QAudioInput</a> will enter the <a href="qaudio.html#State-enum">StoppedState</a> when an error is encountered. Connect to the <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal to handle the error:</p>
<pre class="cpp">
<span class="type">void</span> AudioInputExample<span class="operator">::</span>handleStateChanged(<span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>State newState)
{
<span class="keyword">switch</span> (newState) {
<span class="keyword">case</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>StoppedState:
<span class="keyword">if</span> (audio<span class="operator">-</span><span class="operator">></span>error() <span class="operator">!</span><span class="operator">=</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>NoError) {
<span class="comment">// Error handling</span>
} <span class="keyword">else</span> {
<span class="comment">// Finished recording</span>
}
<span class="keyword">break</span>;
<span class="keyword">case</span> <span class="type"><a href="qaudio.html">QAudio</a></span><span class="operator">::</span>ActiveState:
<span class="comment">// Started recording - read from IO device</span>
<span class="keyword">break</span>;
<span class="keyword">default</span>:
<span class="comment">// ... other cases as appropriate</span>
<span class="keyword">break</span>;
}
}
</pre>
</div>
<p><b>See also </b><a href="qaudiooutput.html">QAudioOutput</a> and <a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a>.</p>
<!-- @@@QAudioInput -->
<div class="func">
<h2>Member Function Documentation</h2>
<!-- $$$QAudioInput[overload1]$$$QAudioInputconstQAudioFormat&QObject* -->
<h3 class="fn" id="QAudioInput"><a name="QAudioInput"></a>QAudioInput::<span class="name">QAudioInput</span>(const <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> &<i>format</i> = QAudioFormat(), <span class="type">QObject</span> *<i>parent</i> = Q_NULLPTR)</h3>
<p>Construct a new audio input and attach it to <i>parent</i>. The default audio input device is used with the output <i>format</i> parameters.</p>
<!-- @@@QAudioInput -->
<!-- $$$QAudioInput$$$QAudioInputconstQAudioDeviceInfo&constQAudioFormat&QObject* -->
<h3 class="fn" id="QAudioInput-1"><a name="QAudioInput-1"></a>QAudioInput::<span class="name">QAudioInput</span>(const <span class="type"><a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a></span> &<i>audioDevice</i>, const <span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> &<i>format</i> = QAudioFormat(), <span class="type">QObject</span> *<i>parent</i> = Q_NULLPTR)</h3>
<p>Construct a new audio input and attach it to <i>parent</i>. The device referenced by <i>audioDevice</i> is used with the input <i>format</i> parameters.</p>
<!-- @@@QAudioInput -->
<!-- $$$~QAudioInput[overload1]$$$~QAudioInput -->
<h3 class="fn" id="dtor.QAudioInput"><a name="dtor.QAudioInput"></a>QAudioInput::<span class="name">~QAudioInput</span>()</h3>
<p>Destroy this audio input.</p>
<!-- @@@~QAudioInput -->
<!-- $$$bufferSize[overload1]$$$bufferSize -->
<h3 class="fn" id="bufferSize"><a name="bufferSize"></a><span class="type">int</span> QAudioInput::<span class="name">bufferSize</span>() const</h3>
<p>Returns the audio buffer size in bytes.</p>
<p>If called before <a href="qaudioinput.html#start-1">start</a>(), returns platform default value. If called before <a href="qaudioinput.html#start-1">start</a>() but <a href="qaudioinput.html#setBufferSize">setBufferSize</a>() was called prior, returns value set by <a href="qaudioinput.html#setBufferSize">setBufferSize</a>(). If called after <a href="qaudioinput.html#start-1">start</a>(), returns the actual buffer size being used. This may not be what was set previously by <a href="qaudioinput.html#setBufferSize">setBufferSize</a>().</p>
<p><b>See also </b><a href="qaudioinput.html#setBufferSize">setBufferSize</a>().</p>
<!-- @@@bufferSize -->
<!-- $$$bytesReady[overload1]$$$bytesReady -->
<h3 class="fn" id="bytesReady"><a name="bytesReady"></a><span class="type">int</span> QAudioInput::<span class="name">bytesReady</span>() const</h3>
<p>Returns the amount of audio data available to read in bytes.</p>
<p>Note: returned value is only valid while in <a href="qaudio.html#State-enum">QAudio::ActiveState</a> or <a href="qaudio.html#State-enum">QAudio::IdleState</a> state, otherwise returns zero.</p>
<!-- @@@bytesReady -->
<!-- $$$elapsedUSecs[overload1]$$$elapsedUSecs -->
<h3 class="fn" id="elapsedUSecs"><a name="elapsedUSecs"></a><span class="type">qint64</span> QAudioInput::<span class="name">elapsedUSecs</span>() const</h3>
<p>Returns the microseconds since <a href="qaudioinput.html#start-1">start</a>() was called, including time in Idle and Suspend states.</p>
<!-- @@@elapsedUSecs -->
<!-- $$$error[overload1]$$$error -->
<h3 class="fn" id="error"><a name="error"></a><span class="type"><a href="qaudio.html#Error-enum">QAudio::Error</a></span> QAudioInput::<span class="name">error</span>() const</h3>
<p>Returns the error state.</p>
<!-- @@@error -->
<!-- $$$format[overload1]$$$format -->
<h3 class="fn" id="format"><a name="format"></a><span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> QAudioInput::<span class="name">format</span>() const</h3>
<p>Returns the <a href="qaudioformat.html">QAudioFormat</a> being used.</p>
<!-- @@@format -->
<!-- $$$notify[overload1]$$$notify -->
<h3 class="fn" id="notify"><a name="notify"></a><code>[signal] </code><span class="type">void</span> QAudioInput::<span class="name">notify</span>()</h3>
<p>This signal is emitted when x ms of audio data has been processed the interval set by <a href="qaudioinput.html#setNotifyInterval">setNotifyInterval</a>(x).</p>
<!-- @@@notify -->
<!-- $$$notifyInterval[overload1]$$$notifyInterval -->
<h3 class="fn" id="notifyInterval"><a name="notifyInterval"></a><span class="type">int</span> QAudioInput::<span class="name">notifyInterval</span>() const</h3>
<p>Returns the notify interval in milliseconds.</p>
<p><b>See also </b><a href="qaudioinput.html#setNotifyInterval">setNotifyInterval</a>().</p>
<!-- @@@notifyInterval -->
<!-- $$$periodSize[overload1]$$$periodSize -->
<h3 class="fn" id="periodSize"><a name="periodSize"></a><span class="type">int</span> QAudioInput::<span class="name">periodSize</span>() const</h3>
<p>Returns the period size in bytes.</p>
<p>Note: This is the recommended read size in bytes.</p>
<!-- @@@periodSize -->
<!-- $$$processedUSecs[overload1]$$$processedUSecs -->
<h3 class="fn" id="processedUSecs"><a name="processedUSecs"></a><span class="type">qint64</span> QAudioInput::<span class="name">processedUSecs</span>() const</h3>
<p>Returns the amount of audio data processed since <a href="qaudioinput.html#start-1">start</a>() was called in microseconds.</p>
<!-- @@@processedUSecs -->
<!-- $$$reset[overload1]$$$reset -->
<h3 class="fn" id="reset"><a name="reset"></a><span class="type">void</span> QAudioInput::<span class="name">reset</span>()</h3>
<p>Drops all audio data in the buffers, resets buffers to zero.</p>
<!-- @@@reset -->
<!-- $$$resume[overload1]$$$resume -->
<h3 class="fn" id="resume"><a name="resume"></a><span class="type">void</span> QAudioInput::<span class="name">resume</span>()</h3>
<p>Resumes processing audio data after a <a href="qaudioinput.html#suspend">suspend</a>().</p>
<p>Sets <a href="qaudioinput.html#error">error</a>() to <a href="qaudio.html#Error-enum">QAudio::NoError</a>. Sets <a href="qaudioinput.html#state">state</a>() to <a href="qaudio.html#State-enum">QAudio::ActiveState</a> if you previously called start(QIODevice*). Sets <a href="qaudioinput.html#state">state</a>() to <a href="qaudio.html#State-enum">QAudio::IdleState</a> if you previously called <a href="qaudioinput.html#start-1">start</a>(). emits <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal.</p>
<!-- @@@resume -->
<!-- $$$setBufferSize[overload1]$$$setBufferSizeint -->
<h3 class="fn" id="setBufferSize"><a name="setBufferSize"></a><span class="type">void</span> QAudioInput::<span class="name">setBufferSize</span>(<span class="type">int</span> <i>value</i>)</h3>
<p>Sets the audio buffer size to <i>value</i> bytes.</p>
<p>Note: This function can be called anytime before <a href="qaudioinput.html#start-1">start</a>(), calls to this are ignored after <a href="qaudioinput.html#start-1">start</a>(). It should not be assumed that the buffer size set is the actual buffer size used, calling <a href="qaudioinput.html#bufferSize">bufferSize</a>() anytime after <a href="qaudioinput.html#start-1">start</a>() will return the actual buffer size being used.</p>
<p><b>See also </b><a href="qaudioinput.html#bufferSize">bufferSize</a>().</p>
<!-- @@@setBufferSize -->
<!-- $$$setNotifyInterval[overload1]$$$setNotifyIntervalint -->
<h3 class="fn" id="setNotifyInterval"><a name="setNotifyInterval"></a><span class="type">void</span> QAudioInput::<span class="name">setNotifyInterval</span>(<span class="type">int</span> <i>ms</i>)</h3>
<p>Sets the interval for <a href="qaudioinput.html#notify">notify</a>() signal to be emitted. This is based on the <i>ms</i> of audio data processed not on actual real-time. The minimum resolution of the timer is platform specific and values should be checked with <a href="qaudioinput.html#notifyInterval">notifyInterval</a>() to confirm actual value being used.</p>
<p><b>See also </b><a href="qaudioinput.html#notifyInterval">notifyInterval</a>().</p>
<!-- @@@setNotifyInterval -->
<!-- $$$setVolume[overload1]$$$setVolumeqreal -->
<h3 class="fn" id="setVolume"><a name="setVolume"></a><span class="type">void</span> QAudioInput::<span class="name">setVolume</span>(<span class="type">qreal</span> <i>volume</i>)</h3>
<p>Sets the input volume to <i>volume</i>.</p>
<p>The volume is scaled linearly from <code>0.0</code> (silence) to <code>1.0</code> (full volume). Values outside this range will be clamped.</p>
<p>If the device does not support adjusting the input volume then <i>volume</i> will be ignored and the input volume will remain at 1.0.</p>
<p>The default volume is <code>1.0</code>.</p>
<p>Note: Adjustments to the volume will change the volume of this audio stream, not the global volume.</p>
<p><b>See also </b><a href="qaudioinput.html#volume">volume</a>().</p>
<!-- @@@setVolume -->
<!-- $$$start[overload1]$$$startQIODevice* -->
<h3 class="fn" id="start"><a name="start"></a><span class="type">void</span> QAudioInput::<span class="name">start</span>(<span class="type">QIODevice</span> *<i>device</i>)</h3>
<p>Starts transferring audio data from the system's audio input to the <i>device</i>. The <i>device</i> must have been opened in the WriteOnly, Append or ReadWrite modes.</p>
<p>If the <a href="qaudioinput.html">QAudioInput</a> is able to successfully get audio data, <a href="qaudioinput.html#state">state</a>() returns either <a href="qaudio.html#State-enum">QAudio::ActiveState</a> or <a href="qaudio.html#State-enum">QAudio::IdleState</a>, <a href="qaudioinput.html#error">error</a>() returns <a href="qaudio.html#Error-enum">QAudio::NoError</a> and the <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal is emitted.</p>
<p>If a problem occurs during this process, <a href="qaudioinput.html#error">error</a>() returns <a href="qaudio.html#Error-enum">QAudio::OpenError</a>, <a href="qaudioinput.html#state">state</a>() returns <a href="qaudio.html#State-enum">QAudio::StoppedState</a> and the <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal is emitted.</p>
<p><b>See also </b>QIODevice.</p>
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<h3 class="fn" id="start-1"><a name="start-1"></a><span class="type">QIODevice</span> *QAudioInput::<span class="name">start</span>()</h3>
<p>Returns a pointer to the internal QIODevice being used to transfer data from the system's audio input. The device will already be open and read() can read data directly from it.</p>
<p><b>Note: </b>The pointer will become invalid after the stream is stopped or if you start another stream.</p><p>If the <a href="qaudioinput.html">QAudioInput</a> is able to access the system's audio device, <a href="qaudioinput.html#state">state</a>() returns <a href="qaudio.html#State-enum">QAudio::IdleState</a>, <a href="qaudioinput.html#error">error</a>() returns <a href="qaudio.html#Error-enum">QAudio::NoError</a> and the <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal is emitted.</p>
<p>If a problem occurs during this process, <a href="qaudioinput.html#error">error</a>() returns <a href="qaudio.html#Error-enum">QAudio::OpenError</a>, <a href="qaudioinput.html#state">state</a>() returns <a href="qaudio.html#State-enum">QAudio::StoppedState</a> and the <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal is emitted.</p>
<p><b>See also </b>QIODevice.</p>
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<h3 class="fn" id="state"><a name="state"></a><span class="type"><a href="qaudio.html#State-enum">QAudio::State</a></span> QAudioInput::<span class="name">state</span>() const</h3>
<p>Returns the state of audio processing.</p>
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<h3 class="fn" id="stateChanged"><a name="stateChanged"></a><code>[signal] </code><span class="type">void</span> QAudioInput::<span class="name">stateChanged</span>(<span class="type"><a href="qaudio.html#State-enum">QAudio::State</a></span> <i>state</i>)</h3>
<p>This signal is emitted when the device <i>state</i> has changed.</p>
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<h3 class="fn" id="stop"><a name="stop"></a><span class="type">void</span> QAudioInput::<span class="name">stop</span>()</h3>
<p>Stops the audio input, detaching from the system resource.</p>
<p>Sets <a href="qaudioinput.html#error">error</a>() to <a href="qaudio.html#Error-enum">QAudio::NoError</a>, <a href="qaudioinput.html#state">state</a>() to <a href="qaudio.html#State-enum">QAudio::StoppedState</a> and emit <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal.</p>
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<h3 class="fn" id="suspend"><a name="suspend"></a><span class="type">void</span> QAudioInput::<span class="name">suspend</span>()</h3>
<p>Stops processing audio data, preserving buffered audio data.</p>
<p>Sets <a href="qaudioinput.html#error">error</a>() to <a href="qaudio.html#Error-enum">QAudio::NoError</a>, <a href="qaudioinput.html#state">state</a>() to <a href="qaudio.html#State-enum">QAudio::SuspendedState</a> and emit <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal.</p>
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<h3 class="fn" id="volume"><a name="volume"></a><span class="type">qreal</span> QAudioInput::<span class="name">volume</span>() const</h3>
<p>Returns the input volume.</p>
<p>If the device does not support adjusting the input volume the returned value will be 1.0.</p>
<p><b>See also </b><a href="qaudioinput.html#setVolume">setVolume</a>().</p>
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