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<a name="gst-plugins-good-plugins-spectrum"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="gst-plugins-good-plugins-spectrum.top_of_page"></a>spectrum</span></h2>
<p>spectrum — Run an FFT on the audio signal, output spectrum data</p>
</td>
<td class="gallery_image" valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-spectrum.properties"></a><h2>Properties</h2>
<div class="informaltable"><table border="0">
<colgroup>
<col width="150px" class="properties_type">
<col width="300px" class="properties_name">
<col width="200px" class="properties_flags">
</colgroup>
<tbody>
<tr>
<td class="property_type"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--bands" title="The “bands” property">bands</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><span class="type">guint64</span></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--interval" title="The “interval” property">interval</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--message" title="The “message” property">message</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--threshold" title="The “threshold” property">threshold</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--message-magnitude" title="The “message-magnitude” property">message-magnitude</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--message-phase" title="The “message-phase” property">message-phase</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--post-messages" title="The “post-messages” property">post-messages</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--multi-channel" title="The “multi-channel” property">multi-channel</a></td>
<td class="property_flags">Read / Write</td>
</tr>
</tbody>
</table></div>
</div>
<a name="GstSpectrum"></a><div class="refsect1">
<a name="gst-plugins-good-plugins-spectrum.other"></a><h2>Types and Values</h2>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="name">
<col class="description">
</colgroup>
<tbody><tr>
<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum-struct" title="struct GstSpectrum">GstSpectrum</a></td>
</tr></tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-spectrum.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="screen"> <a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a>
<span class="lineart">╰──</span> <a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a>
<span class="lineart">╰──</span> <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstObject.html">GstObject</a>
<span class="lineart">╰──</span> <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html">GstElement</a>
<span class="lineart">╰──</span> <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstBaseTransform.html">GstBaseTransform</a>
<span class="lineart">╰──</span> <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-gstaudiofilter.html#GstAudioFilter">GstAudioFilter</a>
<span class="lineart">╰──</span> GstSpectrum
</pre>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-spectrum.description"></a><h2>Description</h2>
<p>The Spectrum element analyzes the frequency spectrum of an audio signal.
If the <a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--post-messages" title="The “post-messages” property"><span class="type">“post-messages”</span></a> property is <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><span class="type">TRUE</span></a>, it sends analysis results
as element messages named</p>
<code class="classname">"spectrum"</code> after each interval of time given
<p>by the <a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--interval" title="The “interval” property"><span class="type">“interval”</span></a> property.</p>
<p>The message's structure contains some combination of these fields:</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"timestamp"</code>:
the timestamp of the buffer that triggered the message.
</p></li>
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"stream-time"</code>:
the stream time of the buffer.
</p></li>
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"running-time"</code>:
the running_time of the buffer.
</p></li>
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"duration"</code>:
the duration of the buffer.
</p></li>
<li class="listitem"><p>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
<code class="classname">"endtime"</code>:
the end time of the buffer that triggered the message as stream time (this
is deprecated, as it can be calculated from stream-time + duration)
</p></li>
<li class="listitem"><p>
<span class="type">GstValueList</span> of <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gfloat"><span class="type">gfloat</span></a>
<code class="classname">"magnitude"</code>:
the level for each frequency band in dB. All values below the value of the
<a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--threshold" title="The “threshold” property"><span class="type">“threshold”</span></a> property will be set to the threshold. Only present
if the <a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--message-magnitude" title="The “message-magnitude” property"><span class="type">“message-magnitude”</span></a> property is <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.
</p></li>
<li class="listitem"><p>
<span class="type">GstValueList</span> of <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gfloat"><span class="type">gfloat</span></a>
<code class="classname">"phase"</code>:
The phase for each frequency band. The value is between -pi and pi. Only
present if the <a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--message-phase" title="The “message-phase” property"><span class="type">“message-phase”</span></a> property is <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.
</p></li>
</ul></div>
<p>If <a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--multi-channel" title="The “multi-channel” property"><span class="type">“multi-channel”</span></a> property is set to true. magnitude and phase
fields will be each a nested <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstControlSource.html#GstValueArray"><span class="type">GstValueArray</span></a>. The first dimension are the
channels and the second dimension are the values.</p>
<div class="refsect2">
<a name="id-1.2.142.7.8"></a><h3>Example application</h3>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
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<td class="listing_code"><pre class="programlisting"><span class="comment">/* GStreamer</span>
<span class="comment"> * Copyright (C) 2006 Stefan Kost &lt;ensonic&#64;users.sf.net&gt;</span>
<span class="comment"> * Copyright (C) 2008 Jan Schmidt &lt;jan.schmidt&#64;sun.com&gt;</span>
<span class="comment"> *</span>
<span class="comment"> * This library is free software; you can redistribute it and/or</span>
<span class="comment"> * modify it under the terms of the GNU Library General Public</span>
<span class="comment"> * License as published by the Free Software Foundation; either</span>
<span class="comment"> * version 2 of the License, or (at your option) any later version.</span>
<span class="comment"> *</span>
<span class="comment"> * This library is distributed in the hope that it will be useful,</span>
<span class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<span class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</span>
<span class="comment"> * Library General Public License for more details.</span>
<span class="comment"> *</span>
<span class="comment"> * You should have received a copy of the GNU Library General Public</span>
<span class="comment"> * License along with this library; if not, write to the</span>
<span class="comment"> * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,</span>
<span class="comment"> * Boston, MA 02110-1301, USA.</span>
<span class="comment"> */</span>
<span class="gtkdoc ppc">#include &lt;stdio.h&gt;</span>
<span class="gtkdoc ppc">#include &lt;string.h&gt;</span>
<span class="gtkdoc ppc">#include &lt;stdlib.h&gt;</span>
<span class="gtkdoc ppc">#include &lt;gst/gst.h&gt;</span>
<span class="gtkdoc kwb">static</span> guint spect_bands <span class="gtkdoc opt">=</span> <span class="number">20</span><span class="gtkdoc opt">;</span>
<span class="gtkdoc ppc">#define AUDIOFREQ 32000</span>
<span class="comment">/* receive spectral data from element message */</span>
<span class="gtkdoc kwb">static</span> gboolean
<span class="function">message_handler</span> <span class="gtkdoc opt">(</span>GstBus <span class="gtkdoc opt">*</span> bus<span class="gtkdoc opt">,</span> GstMessage <span class="gtkdoc opt">*</span> message<span class="gtkdoc opt">,</span> gpointer data<span class="gtkdoc opt">)</span>
<span class="gtkdoc opt">{</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(</span>message<span class="gtkdoc opt">-&gt;</span>type <span class="gtkdoc opt">==</span> GST_MESSAGE_ELEMENT<span class="gtkdoc opt">) {</span>
<span class="gtkdoc kwb">const</span> GstStructure <span class="gtkdoc opt">*</span>s <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstMessage.html#gst-message-get-structure">gst_message_get_structure</a></span> <span class="gtkdoc opt">(</span>message<span class="gtkdoc opt">);</span>
<span class="gtkdoc kwb">const</span> gchar <span class="gtkdoc opt">*</span>name <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstStructure.html#gst-structure-get-name">gst_structure_get_name</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">);</span>
GstClockTime endtime<span class="gtkdoc opt">;</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(</span><span class="function">strcmp</span> <span class="gtkdoc opt">(</span>name<span class="gtkdoc opt">,</span> <span class="string">&quot;spectrum&quot;</span><span class="gtkdoc opt">) ==</span> <span class="number">0</span><span class="gtkdoc opt">) {</span>
<span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>magnitudes<span class="gtkdoc opt">;</span>
<span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>phases<span class="gtkdoc opt">;</span>
<span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>mag<span class="gtkdoc opt">, *</span>phase<span class="gtkdoc opt">;</span>
gdouble freq<span class="gtkdoc opt">;</span>
guint i<span class="gtkdoc opt">;</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstStructure.html#gst-structure-get-clock-time">gst_structure_get_clock_time</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">,</span> <span class="string">&quot;endtime&quot;</span><span class="gtkdoc opt">, &amp;</span>endtime<span class="gtkdoc opt">))</span>
endtime <span class="gtkdoc opt">=</span> GST_CLOCK_TIME_NONE<span class="gtkdoc opt">;</span>
<span class="function"><a href="https://developer.gnome.org/glib/unstable/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;New spectrum message, endtime %&quot;</span> GST_TIME_FORMAT <span class="string">&quot;</span><span class="gtkdoc esc">\n</span><span class="string">&quot;</span><span class="gtkdoc opt">,</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstInfo.html#GST-TIME-ARGS:CAPS">GST_TIME_ARGS</a></span> <span class="gtkdoc opt">(</span>endtime<span class="gtkdoc opt">));</span>
magnitudes <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstStructure.html#gst-structure-get-value">gst_structure_get_value</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">,</span> <span class="string">&quot;magnitude&quot;</span><span class="gtkdoc opt">);</span>
phases <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstStructure.html#gst-structure-get-value">gst_structure_get_value</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">,</span> <span class="string">&quot;phase&quot;</span><span class="gtkdoc opt">);</span>
<span class="keyword">for</span> <span class="gtkdoc opt">(</span>i <span class="gtkdoc opt">=</span> <span class="number">0</span><span class="gtkdoc opt">;</span> i <span class="gtkdoc opt">&lt;</span> spect_bands<span class="gtkdoc opt">; ++</span>i<span class="gtkdoc opt">) {</span>
freq <span class="gtkdoc opt">= (</span>gdouble<span class="gtkdoc opt">) ((</span>AUDIOFREQ <span class="gtkdoc opt">/</span> <span class="number">2</span><span class="gtkdoc opt">) *</span> i <span class="gtkdoc opt">+</span> AUDIOFREQ <span class="gtkdoc opt">/</span> <span class="number">4</span><span class="gtkdoc opt">) /</span> spect_bands<span class="gtkdoc opt">;</span>
mag <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstValue.html#gst-value-list-get-value">gst_value_list_get_value</a></span> <span class="gtkdoc opt">(</span>magnitudes<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
phase <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstValue.html#gst-value-list-get-value">gst_value_list_get_value</a></span> <span class="gtkdoc opt">(</span>phases<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(</span>mag <span class="gtkdoc opt">!=</span> NULL <span class="gtkdoc opt">&amp;&amp;</span> phase <span class="gtkdoc opt">!=</span> NULL<span class="gtkdoc opt">) {</span>
<span class="function"><a href="https://developer.gnome.org/glib/unstable/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;band %d (freq %g): magnitude %f dB phase %f</span><span class="gtkdoc esc">\n</span><span class="string">&quot;</span><span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">,</span> freq<span class="gtkdoc opt">,</span>
<span class="function"><a href="https://developer.gnome.org/gobject/unstable/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-float">g_value_get_float</a></span> <span class="gtkdoc opt">(</span>mag<span class="gtkdoc opt">),</span> <span class="function"><a href="https://developer.gnome.org/gobject/unstable/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-float">g_value_get_float</a></span> <span class="gtkdoc opt">(</span>phase<span class="gtkdoc opt">));</span>
<span class="gtkdoc opt">}</span>
<span class="gtkdoc opt">}</span>
<span class="function"><a href="https://developer.gnome.org/glib/unstable/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;</span><span class="gtkdoc esc">\n</span><span class="string">&quot;</span><span class="gtkdoc opt">);</span>
<span class="gtkdoc opt">}</span>
<span class="gtkdoc opt">}</span>
<span class="keyword">return</span> TRUE<span class="gtkdoc opt">;</span>
<span class="gtkdoc opt">}</span>
<span class="gtkdoc kwb">int</span>
<span class="function">main</span> <span class="gtkdoc opt">(</span><span class="gtkdoc kwb">int</span> argc<span class="gtkdoc opt">,</span> <span class="gtkdoc kwb">char</span> <span class="gtkdoc opt">*</span>argv<span class="gtkdoc opt">[])</span>
<span class="gtkdoc opt">{</span>
GstElement <span class="gtkdoc opt">*</span>bin<span class="gtkdoc opt">;</span>
GstElement <span class="gtkdoc opt">*</span>src<span class="gtkdoc opt">, *</span>audioconvert<span class="gtkdoc opt">, *</span>spectrum<span class="gtkdoc opt">, *</span>sink<span class="gtkdoc opt">;</span>
GstBus <span class="gtkdoc opt">*</span>bus<span class="gtkdoc opt">;</span>
GstCaps <span class="gtkdoc opt">*</span>caps<span class="gtkdoc opt">;</span>
GMainLoop <span class="gtkdoc opt">*</span>loop<span class="gtkdoc opt">;</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-Gst.html#gst-init">gst_init</a></span> <span class="gtkdoc opt">(&amp;</span>argc<span class="gtkdoc opt">, &amp;</span>argv<span class="gtkdoc opt">);</span>
bin <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPipeline.html#gst-pipeline-new">gst_pipeline_new</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;bin&quot;</span><span class="gtkdoc opt">);</span>
src <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;audiotestsrc&quot;</span><span class="gtkdoc opt">,</span> <span class="string">&quot;src&quot;</span><span class="gtkdoc opt">);</span>
<span class="function"><a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>src<span class="gtkdoc opt">),</span> <span class="string">&quot;wave&quot;</span><span class="gtkdoc opt">,</span> <span class="number">0</span><span class="gtkdoc opt">,</span> <span class="string">&quot;freq&quot;</span><span class="gtkdoc opt">,</span> <span class="number">6000.0</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
audioconvert <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;audioconvert&quot;</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="https://developer.gnome.org/glib/unstable/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>audioconvert<span class="gtkdoc opt">);</span>
spectrum <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;spectrum&quot;</span><span class="gtkdoc opt">,</span> <span class="string">&quot;spectrum&quot;</span><span class="gtkdoc opt">);</span>
<span class="function"><a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>spectrum<span class="gtkdoc opt">),</span> <span class="string">&quot;bands&quot;</span><span class="gtkdoc opt">,</span> spect_bands<span class="gtkdoc opt">,</span> <span class="string">&quot;threshold&quot;</span><span class="gtkdoc opt">, -</span><span class="number">80</span><span class="gtkdoc opt">,</span>
<span class="string">&quot;post-messages&quot;</span><span class="gtkdoc opt">,</span> TRUE<span class="gtkdoc opt">,</span> <span class="string">&quot;message-phase&quot;</span><span class="gtkdoc opt">,</span> TRUE<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
sink <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;fakesink&quot;</span><span class="gtkdoc opt">,</span> <span class="string">&quot;sink&quot;</span><span class="gtkdoc opt">);</span>
<span class="function"><a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>sink<span class="gtkdoc opt">),</span> <span class="string">&quot;sync&quot;</span><span class="gtkdoc opt">,</span> TRUE<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstBin.html#gst-bin-add-many">gst_bin_add_many</a></span> <span class="gtkdoc opt">(</span><span class="function">GST_BIN</span> <span class="gtkdoc opt">(</span>bin<span class="gtkdoc opt">),</span> src<span class="gtkdoc opt">,</span> audioconvert<span class="gtkdoc opt">,</span> spectrum<span class="gtkdoc opt">,</span> sink<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
caps <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstCaps.html#gst-caps-new-simple">gst_caps_new_simple</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;audio/x-raw&quot;</span><span class="gtkdoc opt">,</span>
<span class="string">&quot;rate&quot;</span><span class="gtkdoc opt">,</span> G_TYPE_INT<span class="gtkdoc opt">,</span> AUDIOFREQ<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-link">gst_element_link</a></span> <span class="gtkdoc opt">(</span>src<span class="gtkdoc opt">,</span> audioconvert<span class="gtkdoc opt">) ||</span>
<span class="gtkdoc opt">!</span><span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-link-filtered">gst_element_link_filtered</a></span> <span class="gtkdoc opt">(</span>audioconvert<span class="gtkdoc opt">,</span> spectrum<span class="gtkdoc opt">,</span> caps<span class="gtkdoc opt">) ||</span>
<span class="gtkdoc opt">!</span><span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-link">gst_element_link</a></span> <span class="gtkdoc opt">(</span>spectrum<span class="gtkdoc opt">,</span> sink<span class="gtkdoc opt">)) {</span>
<span class="function">fprintf</span> <span class="gtkdoc opt">(</span>stderr<span class="gtkdoc opt">,</span> <span class="string">&quot;can't link elements</span><span class="gtkdoc esc">\n</span><span class="string">&quot;</span><span class="gtkdoc opt">);</span>
<span class="function">exit</span> <span class="gtkdoc opt">(</span><span class="number">1</span><span class="gtkdoc opt">);</span>
<span class="gtkdoc opt">}</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstCaps.html#gst-caps-unref">gst_caps_unref</a></span> <span class="gtkdoc opt">(</span>caps<span class="gtkdoc opt">);</span>
bus <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-get-bus">gst_element_get_bus</a></span> <span class="gtkdoc opt">(</span>bin<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstBus.html#gst-bus-add-watch">gst_bus_add_watch</a></span> <span class="gtkdoc opt">(</span>bus<span class="gtkdoc opt">,</span> message_handler<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstObject.html#gst-object-unref">gst_object_unref</a></span> <span class="gtkdoc opt">(</span>bus<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-set-state">gst_element_set_state</a></span> <span class="gtkdoc opt">(</span>bin<span class="gtkdoc opt">,</span> GST_STATE_PLAYING<span class="gtkdoc opt">);</span>
<span class="comment">/* we need to run a GLib main loop to get the messages */</span>
loop <span class="gtkdoc opt">=</span> <span class="function"><a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#g-main-loop-new">g_main_loop_new</a></span> <span class="gtkdoc opt">(</span>NULL<span class="gtkdoc opt">,</span> FALSE<span class="gtkdoc opt">);</span>
<span class="function"><a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#g-main-loop-run">g_main_loop_run</a></span> <span class="gtkdoc opt">(</span>loop<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-set-state">gst_element_set_state</a></span> <span class="gtkdoc opt">(</span>bin<span class="gtkdoc opt">,</span> GST_STATE_NULL<span class="gtkdoc opt">);</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstObject.html#gst-object-unref">gst_object_unref</a></span> <span class="gtkdoc opt">(</span>bin<span class="gtkdoc opt">);</span>
<span class="keyword">return</span> <span class="number">0</span><span class="gtkdoc opt">;</span>
<span class="gtkdoc opt">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="refsynopsisdiv">
<h2>Synopsis</h2>
<div class="refsect2">
<a name="id-1.2.142.7.9.1"></a><h3>Element Information</h3>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">plugin</span></p></td>
<td>
<a class="link" href="gst-plugins-good-plugins-plugin-spectrum.html#plugin-spectrum">spectrum</a>
</td>
</tr>
<tr>
<td><p><span class="term">author</span></p></td>
<td>Erik Walthinsen &lt;omega@cse.ogi.edu&gt;, Stefan Kost &lt;ensonic@users.sf.net&gt;, Sebastian Dröge &lt;sebastian.droege@collabora.co.uk&gt;</td>
</tr>
<tr>
<td><p><span class="term">class</span></p></td>
<td>Filter/Analyzer/Audio</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="id-1.2.142.7.9.2"></a><h3>Element Pads</h3>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>audio/x-raw, format=(string){ S16LE, S24LE, S32LE, F32LE, F64LE }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
</tbody>
</table></div>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>src</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>source</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>audio/x-raw, format=(string){ S16LE, S24LE, S32LE, F32LE, F64LE }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
</tbody>
</table></div>
</div>
</div>
<p>
</p>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-spectrum.functions_details"></a><h2>Functions</h2>
<p></p>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-spectrum.other_details"></a><h2>Types and Values</h2>
<div class="refsect2">
<a name="GstSpectrum-struct"></a><h3>struct GstSpectrum</h3>
<pre class="programlisting">struct GstSpectrum;</pre>
<p>
</p>
</div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-spectrum.property-details"></a><h2>Property Details</h2>
<div class="refsect2">
<a name="GstSpectrum--bands"></a><h3>The <code class="literal">“bands”</code> property</h3>
<pre class="programlisting"> “bands” <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a></pre>
<p>Number of frequency bands.</p>
<p>Flags: Read / Write</p>
<p>Allowed values: [2,1073741824]</p>
<p>Default value: 128</p>
</div>
<hr>
<div class="refsect2">
<a name="GstSpectrum--interval"></a><h3>The <code class="literal">“interval”</code> property</h3>
<pre class="programlisting"> “interval” <span class="type">guint64</span></pre>
<p>Interval of time between message posts (in nanoseconds).</p>
<p>Flags: Read / Write</p>
<p>Allowed values: &gt;= 1</p>
<p>Default value: 100000000</p>
</div>
<hr>
<div class="refsect2">
<a name="GstSpectrum--message"></a><h3>The <code class="literal">“message”</code> property</h3>
<pre class="programlisting"> “message” <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre>
<p>Whether to post a 'spectrum' element message on the bus for each passed interval (deprecated, use post-messages).</p>
<p>Flags: Read / Write</p>
<p>Default value: TRUE</p>
</div>
<hr>
<div class="refsect2">
<a name="GstSpectrum--threshold"></a><h3>The <code class="literal">“threshold”</code> property</h3>
<pre class="programlisting"> “threshold” <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a></pre>
<p>dB threshold for result. All lower values will be set to this.</p>
<p>Flags: Read / Write</p>
<p>Allowed values: &lt;= 0</p>
<p>Default value: -60</p>
</div>
<hr>
<div class="refsect2">
<a name="GstSpectrum--message-magnitude"></a><h3>The <code class="literal">“message-magnitude”</code> property</h3>
<pre class="programlisting"> “message-magnitude” <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre>
<p>Whether to add a 'magnitude' field to the structure of any 'spectrum' element messages posted on the bus.</p>
<p>Flags: Read / Write</p>
<p>Default value: TRUE</p>
</div>
<hr>
<div class="refsect2">
<a name="GstSpectrum--message-phase"></a><h3>The <code class="literal">“message-phase”</code> property</h3>
<pre class="programlisting"> “message-phase” <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre>
<p>Whether to add a 'phase' field to the structure of any 'spectrum' element messages posted on the bus.</p>
<p>Flags: Read / Write</p>
<p>Default value: FALSE</p>
</div>
<hr>
<div class="refsect2">
<a name="GstSpectrum--post-messages"></a><h3>The <code class="literal">“post-messages”</code> property</h3>
<pre class="programlisting"> “post-messages” <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre>
<p>Whether to post a 'spectrum' element message on the bus for each passed interval.</p>
<p>Flags: Read / Write</p>
<p>Default value: TRUE</p>
</div>
<hr>
<div class="refsect2">
<a name="GstSpectrum--multi-channel"></a><h3>The <code class="literal">“multi-channel”</code> property</h3>
<pre class="programlisting"> “multi-channel” <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre>
<p>Send separate results for each channel.</p>
<p>Flags: Read / Write</p>
<p>Default value: FALSE</p>
</div>
</div>
</div>
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