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</style></head><body><table border="0" cellpadding="0" cellspacing="0" width="100%"><tr /><td align="left" valign="top" width="32"><img align="left" border="0" height="32" src="images/rb-logo.png" width="32" /></td><td width="1">  </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a> · <a href="classes.html"><font color="#004faf">All Classes</font></a> · <a href="modules.html"><font color="#004faf">Modules</font></a></td></table><h1 align="center">QAudioInput Class Reference<br /><sup><sup>[<a href="qtmultimedia.html">QtMultimedia</a> module]</sup></sup></h1><p>The QAudioInput class provides an interface for receiving audio
data from an audio input device. <a href="#details">More...</a></p>
<p>Inherits <a href="qobject.html">QObject</a>.</p><h3>Methods</h3><ul><li><div class="fn" /><b><a href="qaudioinput.html#QAudioInput">__init__</a></b> (<i>self</i>, QAudioFormat <i>format</i> = QAudioFormat(), QObject <i>parent</i> = None)</li><li><div class="fn" /><b><a href="qaudioinput.html#QAudioInput-2">__init__</a></b> (<i>self</i>, QAudioDeviceInfo <i>audioDevice</i>, QAudioFormat <i>format</i> = QAudioFormat(), QObject <i>parent</i> = None)</li><li><div class="fn" />int <b><a href="qaudioinput.html#bufferSize">bufferSize</a></b> (<i>self</i>)</li><li><div class="fn" />int <b><a href="qaudioinput.html#bytesReady">bytesReady</a></b> (<i>self</i>)</li><li><div class="fn" />int <b><a href="qaudioinput.html#elapsedUSecs">elapsedUSecs</a></b> (<i>self</i>)</li><li><div class="fn" />QAudio.Error <b><a href="qaudioinput.html#error">error</a></b> (<i>self</i>)</li><li><div class="fn" />QAudioFormat <b><a href="qaudioinput.html#format">format</a></b> (<i>self</i>)</li><li><div class="fn" />int <b><a href="qaudioinput.html#notifyInterval">notifyInterval</a></b> (<i>self</i>)</li><li><div class="fn" />int <b><a href="qaudioinput.html#periodSize">periodSize</a></b> (<i>self</i>)</li><li><div class="fn" />int <b><a href="qaudioinput.html#processedUSecs">processedUSecs</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qaudioinput.html#reset">reset</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qaudioinput.html#resume">resume</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qaudioinput.html#setBufferSize">setBufferSize</a></b> (<i>self</i>, int <i>bytes</i>)</li><li><div class="fn" /><b><a href="qaudioinput.html#setNotifyInterval">setNotifyInterval</a></b> (<i>self</i>, int <i>milliSeconds</i>)</li><li><div class="fn" /><b><a href="qaudioinput.html#start">start</a></b> (<i>self</i>, QIODevice <i>device</i>)</li><li><div class="fn" />QIODevice <b><a href="qaudioinput.html#start-2">start</a></b> (<i>self</i>)</li><li><div class="fn" />QAudio.State <b><a href="qaudioinput.html#state">state</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qaudioinput.html#stop">stop</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qaudioinput.html#suspend">suspend</a></b> (<i>self</i>)</li></ul><h3>Qt Signals</h3><ul><li><div class="fn" />void <b><a href="qaudioinput.html#notify">notify</a></b> ()</li><li><div class="fn" />void <b><a href="qaudioinput.html#stateChanged">stateChanged</a></b> (QAudio::State)</li></ul><a name="details" /><hr /><h2>Detailed Description</h2><p>The QAudioInput 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 QAudioInput 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>QAudioInput 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 QAudioInput is simply a matter of calling
<a href="qaudioinput.html#start">start</a>() with a <a href="qiodevice.html">QIODevice</a> opened for writing. For instance, to
record to a file, you can:</p>
<pre class="cpp">
<span class="type"><a href="qfile.html">QFile</a></span> outputFile; <span class="comment">// class member.</span>
<span class="type">QAudioInput</span> <span class="operator">*</span>audioInput; <span class="comment">// class member.</span>
...
<span class="type">void</span> startRecording()
{
outputFile<span class="operator">.</span>setFileName(<span class="string">"/tmp/test.raw"</span>);
outputFile<span class="operator">.</span>open( <span class="type"><a href="qiodevice.html">QIODevice</a></span><span class="operator">.</span>WriteOnly <span class="operator">|</span> <span class="type"><a href="qiodevice.html">QIODevice</a></span><span class="operator">.</span>Truncate );
<span class="type"><a href="qaudioformat.html">QAudioFormat</a></span> format;
<span class="comment">// set up the format you want, eg.</span>
format<span class="operator">.</span>setFrequency(<span class="number">8000</span>);
format<span class="operator">.</span>setChannels(<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)) {
<a href="qtcore.html#qWarning">qWarning</a>()<span class="operator"><</span><span class="operator"><</span><span class="string">"default format not supported try to use nearest"</span>;
format <span class="operator">=</span> info<span class="operator">.</span>nearestFormat(format);
}
audioInput <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QAudioInput</span>(format<span class="operator">,</span> <span class="keyword">this</span>);
<span class="type"><a href="qtimer.html">QTimer</a></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()));
audioInput<span class="operator">-</span><span class="operator">></span>start(<span class="operator">&</span>outputFile);
<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 <tt>stopRecording()</tt> slot.</p>
<pre class="cpp">
<span class="type">void</span> stopRecording()
{
audioInput<span class="operator">-</span><span class="operator">></span>stop();
outputFile<span class="operator">.</span>close();
<span class="keyword">delete</span> audioInput;
}
</pre>
<p>At any point in time, QAudioInput 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">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>QAudioInput provides several ways of measuring the time that has
passed since the <a href="qaudioinput.html#start">start</a>() of
the recording. The <tt>processedUSecs()</tt> 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">start</a>()
was called regardless of which states the QAudioInput 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 QAudioInput
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> stateChanged(<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> (audioInput<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">// Perform error handling</span>
} <span class="keyword">else</span> {
}
<span class="keyword">break</span>;
</pre>
<a id="symbian-platform-security-requirements" name="symbian-platform-security-requirements" />
<h3>Symbian Platform Security Requirements</h3>
<p>On Symbian, processes which use this class must have the
<tt>UserEnvironment</tt> platform security capability. If the
client process lacks this capability, calls to either overload of
<a href="qaudioinput.html#start">start</a>() will fail. This
failure is indicated by the QAudioInput object setting its <a href="qaudioinput.html#error">error</a>() value to <a href="qaudio.html#Error-enum">QAudio.OpenError</a> and then emitting a
<a href="qaudioinput.html#stateChanged">stateChanged</a>(<a href="qaudio.html#State-enum">QAudio.StoppedState</a>) signal.</p>
<p>Platform security capabilities are added via the <a href="qmake-variable-reference.html#target-capability">TARGET.CAPABILITY</a>
qmake variable.</p>
<hr /><h2>Method Documentation</h2><h3 class="fn"><a name="QAudioInput" />QAudioInput.__init__ (<i>self</i>, <a href="qaudioformat.html">QAudioFormat</a> <i>format</i> = QAudioFormat(), <a href="qobject.html">QObject</a> <i>parent</i> = None)</h3><p>The <i>parent</i> argument, if not None, causes <i>self</i> to be owned by Qt instead of PyQt.</p><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>
<h3 class="fn"><a name="QAudioInput-2" />QAudioInput.__init__ (<i>self</i>, <a href="qaudiodeviceinfo.html">QAudioDeviceInfo</a> <i>audioDevice</i>, <a href="qaudioformat.html">QAudioFormat</a> <i>format</i> = QAudioFormat(), <a href="qobject.html">QObject</a> <i>parent</i> = None)</h3><p>The <i>parent</i> argument, if not None, causes <i>self</i> to be owned by Qt instead of PyQt.</p><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>
<h3 class="fn"><a name="bufferSize" />int QAudioInput.bufferSize (<i>self</i>)</h3><p>Returns the audio buffer size in milliseconds.</p>
<p>If called before <a href="qaudioinput.html#start">start</a>(),
returns platform default value. If called before <a href="qaudioinput.html#start">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">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>
<h3 class="fn"><a name="bytesReady" />int QAudioInput.bytesReady (<i>self</i>)</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>
<h3 class="fn"><a name="elapsedUSecs" />int QAudioInput.elapsedUSecs (<i>self</i>)</h3><p>Returns the microseconds since <a href="qaudioinput.html#start">start</a>() was called, including time in
Idle and Suspend states.</p>
<h3 class="fn"><a name="error" /><a href="qaudio.html#Error-enum">QAudio.Error</a> QAudioInput.error (<i>self</i>)</h3><p>Returns the error state.</p>
<h3 class="fn"><a name="format" /><a href="qaudioformat.html">QAudioFormat</a> QAudioInput.format (<i>self</i>)</h3><p>Returns the <a href="qaudioformat.html">QAudioFormat</a> being
used.</p>
<h3 class="fn"><a name="notifyInterval" />int QAudioInput.notifyInterval (<i>self</i>)</h3><p>Returns the notify interval in milliseconds.</p>
<p><b>See also</b> <a href="qaudioinput.html#setNotifyInterval">setNotifyInterval</a>().</p>
<h3 class="fn"><a name="periodSize" />int QAudioInput.periodSize (<i>self</i>)</h3><p>Returns the period size in bytes.</p>
<p>Note: This is the recommended read size in bytes.</p>
<h3 class="fn"><a name="processedUSecs" />int QAudioInput.processedUSecs (<i>self</i>)</h3><p>Returns the amount of audio data processed since <a href="qaudioinput.html#start">start</a>() was called in
microseconds.</p>
<h3 class="fn"><a name="reset" />QAudioInput.reset (<i>self</i>)</h3><p>Drops all audio data in the buffers, resets buffers to zero.</p>
<h3 class="fn"><a name="resume" />QAudioInput.resume (<i>self</i>)</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(<a href="qiodevice.html">QIODevice</a>*). 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">start</a>(). emits <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal.</p>
<h3 class="fn"><a name="setBufferSize" />QAudioInput.setBufferSize (<i>self</i>, int <i>bytes</i>)</h3><p>Sets the audio buffer size to <i>value</i> milliseconds.</p>
<p>Note: This function can be called anytime before <a href="qaudioinput.html#start">start</a>(), calls to this are ignored
after <a href="qaudioinput.html#start">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">start</a>() will
return the actual buffer size being used.</p>
<p><b>See also</b> <a href="qaudioinput.html#bufferSize">bufferSize</a>().</p>
<h3 class="fn"><a name="setNotifyInterval" />QAudioInput.setNotifyInterval (<i>self</i>, int <i>milliSeconds</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>
<h3 class="fn"><a name="start" />QAudioInput.start (<i>self</i>, <a href="qiodevice.html">QIODevice</a> <i>device</i>)</h3><p>Uses the <i>device</i> as the <a href="qiodevice.html">QIODevice</a> to transfer data. Passing a <a href="qiodevice.html">QIODevice</a> allows the data to be transferred
without any extra code. All that is required is to open the
<a href="qiodevice.html">QIODevice</a>. <a href="qaudioinput.html">QAudioInput</a> does not take ownership of
<i>device</i>.</p>
<p>The <a href="qaudioinput.html">QAudioInput</a> will write to the
device when new data is available. You can subclass <a href="qiodevice.html">QIODevice</a> and reimplement <a href="qiodevice.html#writeData">writeData()</a> if you wish to access
the data. If you simply want to save data to a file, you can pass a
<a href="qfile.html">QFile</a> to this function.</p>
<p>If able to successfully get audio data from the systems audio
device the <a href="qaudioinput.html#state">state</a>() is set to
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>() is set to <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 the <a href="qaudioinput.html#error">error</a>() is set to <a href="qaudio.html#Error-enum">QAudio.OpenError</a>, <a href="qaudioinput.html#state">state</a>() is set to <a href="qaudio.html#State-enum">QAudio.StoppedState</a> and <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal is
emitted.</p>
<p><a href="qaudioinput.html#symbian-platform-security-requirements">QAudioInput#Symbian
Platform Security Requirements</a></p>
<p><b>See also</b> <a href="qiodevice.html">QIODevice</a>.</p>
<h3 class="fn"><a name="start-2" /><a href="qiodevice.html">QIODevice</a> QAudioInput.start (<i>self</i>)</h3><p>Returns a pointer to a new <a href="qiodevice.html">QIODevice</a> that will be used to handle the data
transfer. This <a href="qiodevice.html">QIODevice</a> can be used
to <a href="qiodevice.html#read">read()</a> audio data directly.
You will typically connect to the <a href="qiodevice.html#readyRead">readyRead()</a> signal, and read from
the device in the slot you connect to. <a href="qaudioinput.html">QAudioInput</a> keeps ownership of the
device.</p>
<p>If able to access the systems audio device the <a href="qaudioinput.html#state">state</a>() is set to <a href="qaudio.html#State-enum">QAudio.IdleState</a>, <a href="qaudioinput.html#error">error</a>() is set to <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 the <a href="qaudioinput.html#error">error</a>() is set to <a href="qaudio.html#Error-enum">QAudio.OpenError</a>, <a href="qaudioinput.html#state">state</a>() is set to <a href="qaudio.html#State-enum">QAudio.StoppedState</a> and <a href="qaudioinput.html#stateChanged">stateChanged</a>() signal is
emitted.</p>
<p><a href="qaudioinput.html#symbian-platform-security-requirements">QAudioInput#Symbian
Platform Security Requirements</a></p>
<p><b>See also</b> <a href="qiodevice.html">QIODevice</a>.</p>
<h3 class="fn"><a name="state" /><a href="qaudio.html#State-enum">QAudio.State</a> QAudioInput.state (<i>self</i>)</h3><p>Returns the state of audio processing.</p>
<h3 class="fn"><a name="stop" />QAudioInput.stop (<i>self</i>)</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>
<h3 class="fn"><a name="suspend" />QAudioInput.suspend (<i>self</i>)</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>
<hr /><h2>Qt Signal Documentation</h2><h3 class="fn"><a name="notify" />void notify ()</h3><p>This is the default overload of this signal.</p><p>This signal is emitted when x ms of audio data has been
processed the interval set by setNotifyInterval(x).</p>
<h3 class="fn"><a name="stateChanged" />void stateChanged (QAudio::State)</h3><p>This is the default overload of this signal.</p><p>This signal is emitted when the device <i>state</i> has
changed.</p>
<address><hr /><div align="center"><table border="0" cellspacing="0" width="100%"><tr class="address"><td align="left" width="25%">PyQt 4.10.3 for X11</td><td align="center" width="50%">Copyright © <a href="http://www.riverbankcomputing.com">Riverbank Computing Ltd</a> and <a href="http://www.qtsoftware.com">Nokia</a> 2012</td><td align="right" width="25%">Qt 4.8.5</td></tr></table></div></address></body></html>
