docs/plugins/html/gst-plugins-good-plugins-spectrum.html

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  20 <th width="100%" align="center">GStreamer Good Plugins 0.10 Plugins Reference Manual</th>
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  23 <tr><td colspan="5" class="shortcuts">
  24 <a href="#gst-plugins-good-plugins-spectrum.synopsis" class="shortcut">Top</a>
  25                    |
  26                   <a href="#gst-plugins-good-plugins-spectrum.description" class="shortcut">Description</a>
  27                    |
  28                   <a href="#gst-plugins-good-plugins-spectrum.object-hierarchy" class="shortcut">Object Hierarchy</a>
  29                    |
  30                   <a href="#gst-plugins-good-plugins-spectrum.properties" class="shortcut">Properties</a>
  31 </td></tr>
  32 </table>
  33 <div class="refentry">
  34 <a name="gst-plugins-good-plugins-spectrum"></a><div class="titlepage"></div>
  35 <div class="refnamediv"><table width="100%"><tr>
  36 <td valign="top">
  37 <h2><span class="refentrytitle"><a name="gst-plugins-good-plugins-spectrum.top_of_page"></a>spectrum</span></h2>
  38 <p>spectrum — Run an FFT on the audio signal, output spectrum data</p>
  39 </td>
  40 <td valign="top" align="right"></td>
  41 </tr></table></div>
  42 <div class="refsynopsisdiv">
  43 <a name="gst-plugins-good-plugins-spectrum.synopsis"></a><h2>Synopsis</h2>
  44 <a name="GstSpectrum"></a><pre class="synopsis">struct              <a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum-struct" title="struct GstSpectrum">GstSpectrum</a>;
  45 </pre>
  46 </div>
  47 <div class="refsect1">
  48 <a name="gst-plugins-good-plugins-spectrum.object-hierarchy"></a><h2>Object Hierarchy</h2>
  49 <pre class="synopsis">
  50   <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a>
  51    +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstObject.html">GstObject</a>
  52          +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html">GstElement</a>
  53                +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstBaseTransform.html">GstBaseTransform</a>
  54                      +----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-gstaudiofilter.html#GstAudioFilter">GstAudioFilter</a>
  55                            +----GstSpectrum
  56 </pre>
  57 </div>
  58 <div class="refsect1">
  59 <a name="gst-plugins-good-plugins-spectrum.properties"></a><h2>Properties</h2>
  60 <pre class="synopsis">
  61   "<a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--bands" title='The "bands" property'>bands</a>"                    <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a>                 : Read / Write
  62   "<a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--interval" title='The "interval" property'>interval</a>"                 <span class="type">guint64</span>               : Read / Write
  63   "<a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--message" title='The "message" property'>message</a>"                  <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write
  64   "<a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--threshold" title='The "threshold" property'>threshold</a>"                <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write
  65   "<a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--message-magnitude" title='The "message-magnitude" property'>message-magnitude</a>"        <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write
  66   "<a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--message-phase" title='The "message-phase" property'>message-phase</a>"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write
  67   "<a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--post-messages" title='The "post-messages" property'>post-messages</a>"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write
  68   "<a class="link" href="gst-plugins-good-plugins-spectrum.html#GstSpectrum--multi-channel" title='The "multi-channel" property'>multi-channel</a>"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write
  69 </pre>
  70 </div>
  71 <div class="refsect1">
  72 <a name="gst-plugins-good-plugins-spectrum.description"></a><h2>Description</h2>
  73 <p>
  74 The Spectrum element analyzes the frequency spectrum of an audio signal.
  75 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="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><span class="type">TRUE</span></a>, it sends analysis results
  76 as application messages named
  77 <code class="classname">"spectrum"</code> after each interval of time given
  78 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.
  79 </p>
  80 <p>
  81 The message's structure contains some combination of these fields:
  82 </p>
  83 <div class="itemizedlist"><ul class="itemizedlist" type="disc">
  84 <li class="listitem"><p>
  85   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
  86   <code class="classname">"timestamp"</code>:
  87   the timestamp of the buffer that triggered the message.
  88   </p></li>
  89 <li class="listitem"><p>
  90   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
  91   <code class="classname">"stream-time"</code>:
  92   the stream time of the buffer.
  93   </p></li>
  94 <li class="listitem"><p>
  95   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
  96   <code class="classname">"running-time"</code>:
  97   the running_time of the buffer.
  98   </p></li>
  99 <li class="listitem"><p>
 100   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
 101   <code class="classname">"duration"</code>:
 102   the duration of the buffer.
 103   </p></li>
 104 <li class="listitem"><p>
 105   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
 106   <code class="classname">"endtime"</code>:
 107   the end time of the buffer that triggered the message as stream time (this
 108   is deprecated, as it can be calculated from stream-time + duration)
 109   </p></li>
 110 <li class="listitem"><p>
 111   <span class="type">GstValueList</span> of <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gfloat"><span class="type">gfloat</span></a>
 112   <code class="classname">"magnitude"</code>:
 113   the level for each frequency band in dB. All values below the value of the
 114   <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
 115   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="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.
 116   </p></li>
 117 <li class="listitem"><p>
 118   <span class="type">GstValueList</span> of <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gfloat"><span class="type">gfloat</span></a>
 119   <code class="classname">"phase"</code>:
 120   The phase for each frequency band. The value is between -pi and pi. Only
 121   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="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.
 122   </p></li>
 123 </ul></div>
 124 <p>
 125 </p>
 126 <p>
 127 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
 128 fields will be each a nested <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstControlSource.html#GstValueArray"><span class="type">GstValueArray</span></a>. The first dimension are the
 129 channels and the second dimension are the values.
 130 </p>
 131 <p>
 132 </p>
 133 <div class="refsect2">
 134 <a name="idp22181664"></a><h3>Example application</h3>
 135 <div class="informalexample">
 136   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 137     <tbody>
 138       <tr>
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 262 124</pre></td>
 263         <td class="listing_code"><pre class="programlisting"><span class="comment">/* GStreamer</span>
 264 <span class="comment"> * Copyright (C) 2006 Stefan Kost &lt;ensonic&#64;users.sf.net&gt;</span>
 265 <span class="comment"> * Copyright (C) 2008 Jan Schmidt &lt;jan.schmidt&#64;sun.com&gt;</span>
 266 <span class="comment"> *</span>
 267 <span class="comment"> * This library is free software; you can redistribute it and/or</span>
 268 <span class="comment"> * modify it under the terms of the GNU Library General Public</span>
 269 <span class="comment"> * License as published by the Free Software Foundation; either</span>
 270 <span class="comment"> * version 2 of the License, or (at your option) any later version.</span>
 271 <span class="comment"> *</span>
 272 <span class="comment"> * This library is distributed in the hope that it will be useful,</span>
 273 <span class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
 274 <span class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU</span>
 275 <span class="comment"> * Library General Public License for more details.</span>
 276 <span class="comment"> *</span>
 277 <span class="comment"> * You should have received a copy of the GNU Library General Public</span>
 278 <span class="comment"> * License along with this library; if not, write to the</span>
 279 <span class="comment"> * Free Software Foundation, Inc., 59 Temple Place - Suite 330,</span>
 280 <span class="comment"> * Boston, MA 02111-1307, USA.</span>
 281 <span class="comment"> */</span>
 282
 283 <span class="gtkdoc ppc">#include &lt;stdio.h&gt;</span>
 284 <span class="gtkdoc ppc">#include &lt;string.h&gt;</span>
 285 <span class="gtkdoc ppc">#include &lt;stdlib.h&gt;</span>
 286 <span class="gtkdoc ppc">#include &lt;gst/gst.h&gt;</span>
 287
 288 <span class="gtkdoc kwb">static</span> guint spect_bands <span class="gtkdoc opt">=</span> <span class="number">20</span><span class="gtkdoc opt">;</span>
 289
 290 <span class="gtkdoc ppc">#define AUDIOFREQ 32000</span>
 291
 292 <span class="comment">/* receive spectral data from element message */</span>
 293 <span class="gtkdoc kwb">static</span> gboolean
 294 <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>
 295 <span class="gtkdoc opt">{</span>
 296   <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>
 297     <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/gstreamer-GstMessage.html#gst-message-get-structure">gst_message_get_structure</a></span> <span class="gtkdoc opt">(</span>message<span class="gtkdoc opt">);</span>
 298     <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/gstreamer-GstStructure.html#gst-structure-get-name">gst_structure_get_name</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">);</span>
 299     GstClockTime endtime<span class="gtkdoc opt">;</span>
 300
 301     <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>
 302       <span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>magnitudes<span class="gtkdoc opt">;</span>
 303       <span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>phases<span class="gtkdoc opt">;</span>
 304       <span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>mag<span class="gtkdoc opt">, *</span>phase<span class="gtkdoc opt">;</span>
 305       gdouble freq<span class="gtkdoc opt">;</span>
 306       guint i<span class="gtkdoc opt">;</span>
 307
 308       <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/gstreamer-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>
 309         endtime <span class="gtkdoc opt">=</span> GST_CLOCK_TIME_NONE<span class="gtkdoc opt">;</span>
 310
 311       <span class="function"><a href="http://library.gnome.org/devel/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>
 312           <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>
 313
 314       magnitudes <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-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>
 315       phases <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-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>
 316
 317       <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>
 318         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>
 319         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>
 320         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>
 321
 322         <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>
 323           <span class="function"><a href="http://library.gnome.org/devel/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>
 324               <span class="function"><a href="http://library.gnome.org/devel/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="http://library.gnome.org/devel/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>
 325         <span class="gtkdoc opt">}</span>
 326       <span class="gtkdoc opt">}</span>
 327       <span class="function"><a href="http://library.gnome.org/devel/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>
 328     <span class="gtkdoc opt">}</span>
 329   <span class="gtkdoc opt">}</span>
 330   <span class="keyword">return</span> TRUE<span class="gtkdoc opt">;</span>
 331 <span class="gtkdoc opt">}</span>
 332
 333 <span class="gtkdoc kwb">int</span>
 334 <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>
 335 <span class="gtkdoc opt">{</span>
 336   GstElement <span class="gtkdoc opt">*</span>bin<span class="gtkdoc opt">;</span>
 337   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>
 338   GstBus <span class="gtkdoc opt">*</span>bus<span class="gtkdoc opt">;</span>
 339   GstCaps <span class="gtkdoc opt">*</span>caps<span class="gtkdoc opt">;</span>
 340   GMainLoop <span class="gtkdoc opt">*</span>loop<span class="gtkdoc opt">;</span>
 341
 342   <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>
 343
 344   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>
 345
 346   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>
 347   <span class="function"><a href="http://library.gnome.org/devel/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="http://library.gnome.org/devel/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>
 348   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>
 349   <span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>audioconvert<span class="gtkdoc opt">);</span>
 350
 351   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>
 352   <span class="function"><a href="http://library.gnome.org/devel/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="http://library.gnome.org/devel/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>
 353       <span class="string">&quot;message&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>
 354
 355   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>
 356   <span class="function"><a href="http://library.gnome.org/devel/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="http://library.gnome.org/devel/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>
 357
 358   <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>
 359
 360   caps <span class="gtkdoc opt">=</span> <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstCaps.html#gst-caps-new-simple">gst_caps_new_simple</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;audio/x-raw-int&quot;</span><span class="gtkdoc opt">,</span>
 361       <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>
 362
 363   <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>
 364       <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>
 365       <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>
 366     <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>
 367     <span class="function">exit</span> <span class="gtkdoc opt">(</span><span class="number">1</span><span class="gtkdoc opt">);</span>
 368   <span class="gtkdoc opt">}</span>
 369   <span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstCaps.html#gst-caps-unref">gst_caps_unref</a></span> <span class="gtkdoc opt">(</span>caps<span class="gtkdoc opt">);</span>
 370
 371   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>
 372   <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>
 373   <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>
 374
 375   <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>
 376
 377   <span class="comment">/* we need to run a GLib main loop to get the messages */</span>
 378   loop <span class="gtkdoc opt">=</span> <span class="function"><a href="http://library.gnome.org/devel/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>
 379   <span class="function"><a href="http://library.gnome.org/devel/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>
 380
 381   <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>
 382
 383   <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>
 384
 385   <span class="keyword">return</span> <span class="number">0</span><span class="gtkdoc opt">;</span>
 386 <span class="gtkdoc opt">}</span></pre></td>
 387       </tr>
 388     </tbody>
 389   </table>
 390 </div>
 391
 392 </div>
 393 <p>
 394 </p>
 395 <p>
 396 Last reviewed on 2011-03-10 (0.10.29)
 397 </p>
 398 <div class="refsynopsisdiv">
 399 <h2>Synopsis</h2>
 400 <div class="refsect2">
 401 <a name="idp22154752"></a><h3>Element Information</h3>
 402 <div class="variablelist"><table border="0">
 403 <col align="left" valign="top">
 404 <tbody>
 405 <tr>
 406 <td><p><span class="term">plugin</span></p></td>
 407 <td>
 408             <a class="link" href="gst-plugins-good-plugins-plugin-spectrum.html#plugin-spectrum">spectrum</a>
 409           </td>
 410 </tr>
 411 <tr>
 412 <td><p><span class="term">author</span></p></td>
 413 <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>
 414 </tr>
 415 <tr>
 416 <td><p><span class="term">class</span></p></td>
 417 <td>Filter/Analyzer/Audio</td>
 418 </tr>
 419 </tbody>
 420 </table></div>
 421 </div>
 422 <hr>
 423 <div class="refsect2">
 424 <a name="idp22804672"></a><h3>Element Pads</h3>
 425 <div class="variablelist"><table border="0">
 426 <col align="left" valign="top">
 427 <tbody>
 428 <tr>
 429 <td><p><span class="term">name</span></p></td>
 430 <td>sink</td>
 431 </tr>
 432 <tr>
 433 <td><p><span class="term">direction</span></p></td>
 434 <td>sink</td>
 435 </tr>
 436 <tr>
 437 <td><p><span class="term">presence</span></p></td>
 438 <td>always</td>
 439 </tr>
 440 <tr>
 441 <td><p><span class="term">details</span></p></td>
 442 <td>audio/x-raw-int, width=(int)16, depth=(int)[ 1, 16 ], signed=(boolean)true, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 443 </tr>
 444 <tr>
 445 <td><p><span class="term"></span></p></td>
 446 <td> audio/x-raw-int, width=(int)24, depth=(int)[ 1, 24 ], signed=(boolean)true, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 447 </tr>
 448 <tr>
 449 <td><p><span class="term"></span></p></td>
 450 <td> audio/x-raw-int, width=(int)32, depth=(int)[ 1, 32 ], signed=(boolean)true, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 451 </tr>
 452 <tr>
 453 <td><p><span class="term"></span></p></td>
 454 <td> audio/x-raw-float, width=(int){ 32, 64 }, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 455 </tr>
 456 </tbody>
 457 </table></div>
 458 <div class="variablelist"><table border="0">
 459 <col align="left" valign="top">
 460 <tbody>
 461 <tr>
 462 <td><p><span class="term">name</span></p></td>
 463 <td>src</td>
 464 </tr>
 465 <tr>
 466 <td><p><span class="term">direction</span></p></td>
 467 <td>source</td>
 468 </tr>
 469 <tr>
 470 <td><p><span class="term">presence</span></p></td>
 471 <td>always</td>
 472 </tr>
 473 <tr>
 474 <td><p><span class="term">details</span></p></td>
 475 <td>audio/x-raw-int, width=(int)16, depth=(int)[ 1, 16 ], signed=(boolean)true, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 476 </tr>
 477 <tr>
 478 <td><p><span class="term"></span></p></td>
 479 <td> audio/x-raw-int, width=(int)24, depth=(int)[ 1, 24 ], signed=(boolean)true, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 480 </tr>
 481 <tr>
 482 <td><p><span class="term"></span></p></td>
 483 <td> audio/x-raw-int, width=(int)32, depth=(int)[ 1, 32 ], signed=(boolean)true, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 484 </tr>
 485 <tr>
 486 <td><p><span class="term"></span></p></td>
 487 <td> audio/x-raw-float, width=(int){ 32, 64 }, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 488 </tr>
 489 </tbody>
 490 </table></div>
 491 </div>
 492 </div>
 493 <p>
 494 </p>
 495 </div>
 496 <div class="refsect1">
 497 <a name="gst-plugins-good-plugins-spectrum.details"></a><h2>Details</h2>
 498 <div class="refsect2">
 499 <a name="GstSpectrum-struct"></a><h3>struct GstSpectrum</h3>
 500 <pre class="programlisting">struct GstSpectrum;</pre>
 501 <p>
 502 </p>
 503 </div>
 504 </div>
 505 <div class="refsect1">
 506 <a name="gst-plugins-good-plugins-spectrum.property-details"></a><h2>Property Details</h2>
 507 <div class="refsect2">
 508 <a name="GstSpectrum--bands"></a><h3>The <code class="literal">"bands"</code> property</h3>
 509 <pre class="programlisting">  "bands"                    <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a>                 : Read / Write</pre>
 510 <p>Number of frequency bands.</p>
 511 <p>Default value: 128</p>
 512 </div>
 513 <hr>
 514 <div class="refsect2">
 515 <a name="GstSpectrum--interval"></a><h3>The <code class="literal">"interval"</code> property</h3>
 516 <pre class="programlisting">  "interval"                 <span class="type">guint64</span>               : Read / Write</pre>
 517 <p>Interval of time between message posts (in nanoseconds).</p>
 518 <p>Allowed values: &gt;= 1</p>
 519 <p>Default value: 100000000</p>
 520 </div>
 521 <hr>
 522 <div class="refsect2">
 523 <a name="GstSpectrum--message"></a><h3>The <code class="literal">"message"</code> property</h3>
 524 <pre class="programlisting">  "message"                  <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write</pre>
 525 <p>Whether to post a 'spectrum' element message on the bus for each passed interval (deprecated, use post-messages).</p>
 526 <p>Default value: TRUE</p>
 527 </div>
 528 <hr>
 529 <div class="refsect2">
 530 <a name="GstSpectrum--threshold"></a><h3>The <code class="literal">"threshold"</code> property</h3>
 531 <pre class="programlisting">  "threshold"                <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write</pre>
 532 <p>dB threshold for result. All lower values will be set to this.</p>
 533 <p>Allowed values: &lt;= 0</p>
 534 <p>Default value: -60</p>
 535 </div>
 536 <hr>
 537 <div class="refsect2">
 538 <a name="GstSpectrum--message-magnitude"></a><h3>The <code class="literal">"message-magnitude"</code> property</h3>
 539 <pre class="programlisting">  "message-magnitude"        <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write</pre>
 540 <p>Whether to add a 'magnitude' field to the structure of any 'spectrum' element messages posted on the bus.</p>
 541 <p>Default value: TRUE</p>
 542 </div>
 543 <hr>
 544 <div class="refsect2">
 545 <a name="GstSpectrum--message-phase"></a><h3>The <code class="literal">"message-phase"</code> property</h3>
 546 <pre class="programlisting">  "message-phase"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write</pre>
 547 <p>Whether to add a 'phase' field to the structure of any 'spectrum' element messages posted on the bus.</p>
 548 <p>Default value: FALSE</p>
 549 </div>
 550 <hr>
 551 <div class="refsect2">
 552 <a name="GstSpectrum--post-messages"></a><h3>The <code class="literal">"post-messages"</code> property</h3>
 553 <pre class="programlisting">  "post-messages"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write</pre>
 554 <p>
 555 Post messages on the bus with spectrum information.
 556 </p>
 557 <p>Default value: TRUE</p>
 558 <p class="since">Since 0.10.17</p>
 559 </div>
 560 <hr>
 561 <div class="refsect2">
 562 <a name="GstSpectrum--multi-channel"></a><h3>The <code class="literal">"multi-channel"</code> property</h3>
 563 <pre class="programlisting">  "multi-channel"            <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a>              : Read / Write</pre>
 564 <p>
 565 Send separate results for each channel
 566 </p>
 567 <p>Default value: FALSE</p>
 568 <p class="since">Since 0.10.29</p>
 569 </div>
 570 </div>
 571 </div>
 572 <div class="footer">
 573 <hr>
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