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

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
   2 <html>
   3 <head>
   4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   5 <title>level</title>
   6 <meta name="generator" content="DocBook XSL Stylesheets V1.76.1">
   7 <link rel="home" href="index.html" title="GStreamer Good Plugins 0.10 Plugins Reference Manual">
   8 <link rel="up" href="ch01.html" title="gst-plugins-good Elements">
   9 <link rel="prev" href="gst-plugins-good-plugins-jpegenc.html" title="jpegenc">
  10 <link rel="next" href="gst-plugins-good-plugins-matroskamux.html" title="matroskamux">
  11 <meta name="generator" content="GTK-Doc V1.18 (XML mode)">
  12 <link rel="stylesheet" href="style.css" type="text/css">
  13 </head>
  14 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
  15 <table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2">
  16 <tr valign="middle">
  17 <td><a accesskey="p" href="gst-plugins-good-plugins-jpegenc.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td>
  18 <td><a accesskey="u" href="ch01.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td>
  19 <td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td>
  20 <th width="100%" align="center">GStreamer Good Plugins 0.10 Plugins Reference Manual</th>
  21 <td><a accesskey="n" href="gst-plugins-good-plugins-matroskamux.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
  22 </tr>
  23 <tr><td colspan="5" class="shortcuts">
  24 <a href="#gst-plugins-good-plugins-level.synopsis" class="shortcut">Top</a>
  25                    |
  26                   <a href="#gst-plugins-good-plugins-level.description" class="shortcut">Description</a>
  27                    |
  28                   <a href="#gst-plugins-good-plugins-level.object-hierarchy" class="shortcut">Object Hierarchy</a>
  29                    |
  30                   <a href="#gst-plugins-good-plugins-level.properties" class="shortcut">Properties</a>
  31 </td></tr>
  32 </table>
  33 <div class="refentry">
  34 <a name="gst-plugins-good-plugins-level"></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-level.top_of_page"></a>level</span></h2>
  38 <p>level — RMS/Peak/Decaying Peak Level messager for audio/raw</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-level.synopsis"></a><h2>Synopsis</h2>
  44 <a name="GstLevel"></a><pre class="synopsis">struct              <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel-struct" title="struct GstLevel">GstLevel</a>;
  45 </pre>
  46 </div>
  47 <div class="refsect1">
  48 <a name="gst-plugins-good-plugins-level.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                      +----GstLevel
  55 </pre>
  56 </div>
  57 <div class="refsect1">
  58 <a name="gst-plugins-good-plugins-level.properties"></a><h2>Properties</h2>
  59 <pre class="synopsis">
  60   "<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--interval" title='The "interval" property'>interval</a>"                 <span class="type">guint64</span>               : Read / Write
  61   "<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--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
  62   "<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-falloff" title='The "peak-falloff" property'>peak-falloff</a>"             <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>               : Read / Write
  63   "<a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-ttl" title='The "peak-ttl" property'>peak-ttl</a>"                 <span class="type">guint64</span>               : Read / Write
  64 </pre>
  65 </div>
  66 <div class="refsect1">
  67 <a name="gst-plugins-good-plugins-level.description"></a><h2>Description</h2>
  68 <p>
  69 Level analyses incoming audio buffers and, if the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--message" title='The "message" property'><span class="type">"message"</span></a> property
  70 is <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><span class="type">TRUE</span></a>, generates an element message named
  71 <code class="classname">"level"</code>:
  72 after each interval of time given by the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--interval" title='The "interval" property'><span class="type">"interval"</span></a> property.
  73 The message's structure contains these fields:
  74 </p>
  75 <div class="itemizedlist"><ul class="itemizedlist" type="disc">
  76 <li class="listitem"><p>
  77   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
  78   <code class="classname">"timestamp"</code>:
  79   the timestamp of the buffer that triggered the message.
  80   </p></li>
  81 <li class="listitem"><p>
  82   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
  83   <code class="classname">"stream-time"</code>:
  84   the stream time of the buffer.
  85   </p></li>
  86 <li class="listitem"><p>
  87   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
  88   <code class="classname">"running-time"</code>:
  89   the running_time of the buffer.
  90   </p></li>
  91 <li class="listitem"><p>
  92   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
  93   <code class="classname">"duration"</code>:
  94   the duration of the buffer.
  95   </p></li>
  96 <li class="listitem"><p>
  97   <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a>
  98   <code class="classname">"endtime"</code>:
  99   the end time of the buffer that triggered the message as stream time (this
 100   is deprecated, as it can be calculated from stream-time + duration)
 101   </p></li>
 102 <li class="listitem"><p>
 103   <span class="type">GstValueList</span> of <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>
 104   <code class="classname">"peak"</code>:
 105   the peak power level in dB for each channel
 106   </p></li>
 107 <li class="listitem"><p>
 108   <span class="type">GstValueList</span> of <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>
 109   <code class="classname">"decay"</code>:
 110   the decaying peak power level in dB for each channel
 111   the decaying peak level follows the peak level, but starts dropping
 112   if no new peak is reached after the time given by
 113   the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-ttl" title='The "peak-ttl" property'>the time to live</a>.
 114   When the decaying peak level drops, it does so at the decay rate
 115   as specified by the
 116   <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-falloff" title='The "peak-falloff" property'>the peak falloff rate</a>.
 117   </p></li>
 118 <li class="listitem"><p>
 119   <span class="type">GstValueList</span> of <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>
 120   <code class="classname">"rms"</code>:
 121   the Root Mean Square (or average power) level in dB for each channel
 122   </p></li>
 123 </ul></div>
 124 <p>
 125 </p>
 126 <p>
 127 </p>
 128 <div class="refsect2">
 129 <a name="idp17556384"></a><h3>Example application</h3>
 130 <div class="informalexample">
 131   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 132     <tbody>
 133       <tr>
 134         <td class="listing_lines" align="right"><pre>1
 135 2
 136 3
 137 4
 138 5
 139 6
 140 7
 141 8
 142 9
 143 10
 144 11
 145 12
 146 13
 147 14
 148 15
 149 16
 150 17
 151 18
 152 19
 153 20
 154 21
 155 22
 156 23
 157 24
 158 25
 159 26
 160 27
 161 28
 162 29
 163 30
 164 31
 165 32
 166 33
 167 34
 168 35
 169 36
 170 37
 171 38
 172 39
 173 40
 174 41
 175 42
 176 43
 177 44
 178 45
 179 46
 180 47
 181 48
 182 49
 183 50
 184 51
 185 52
 186 53
 187 54
 188 55
 189 56
 190 57
 191 58
 192 59
 193 60
 194 61
 195 62
 196 63
 197 64
 198 65
 199 66
 200 67
 201 68
 202 69
 203 70
 204 71
 205 72
 206 73
 207 74
 208 75
 209 76
 210 77
 211 78
 212 79
 213 80
 214 81
 215 82
 216 83
 217 84
 218 85
 219 86
 220 87
 221 88
 222 89
 223 90
 224 91
 225 92
 226 93
 227 94
 228 95
 229 96
 230 97
 231 98
 232 99
 233 100
 234 101
 235 102
 236 103
 237 104
 238 105
 239 106
 240 107
 241 108
 242 109
 243 110
 244 111
 245 112
 246 113
 247 114
 248 115
 249 116
 250 117
 251 118
 252 119
 253 120
 254 121
 255 122
 256 123
 257 124
 258 125
 259 126
 260 127
 261 128
 262 129</pre></td>
 263         <td class="listing_code"><pre class="programlisting"><span class="comment">/* GStreamer</span>
 264 <span class="comment"> * Copyright (C) 2000,2001,2002,2003,2005</span>
 265 <span class="comment"> *           Thomas Vander Stichele &lt;thomas at apestaart dot org&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;string.h&gt;</span>
 284 <span class="gtkdoc ppc">#include &lt;math.h&gt;</span>
 285
 286 <span class="gtkdoc ppc">#include &lt;gst/gst.h&gt;</span>
 287
 288 <span class="gtkdoc kwb">static</span> gboolean
 289 <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>
 290 <span class="gtkdoc opt">{</span>
 291
 292   <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>
 293     <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>
 294     <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>
 295
 296     <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;level&quot;</span><span class="gtkdoc opt">) ==</span> <span class="number">0</span><span class="gtkdoc opt">) {</span>
 297       gint channels<span class="gtkdoc opt">;</span>
 298       GstClockTime endtime<span class="gtkdoc opt">;</span>
 299       gdouble rms_dB<span class="gtkdoc opt">,</span> peak_dB<span class="gtkdoc opt">,</span> decay_dB<span class="gtkdoc opt">;</span>
 300       gdouble rms<span class="gtkdoc opt">;</span>
 301       <span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>list<span class="gtkdoc opt">;</span>
 302       <span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>value<span class="gtkdoc opt">;</span>
 303
 304       gint i<span class="gtkdoc opt">;</span>
 305
 306       <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>
 307         <span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Message-Logging.html#g-warning">g_warning</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;Could not parse endtime&quot;</span><span class="gtkdoc opt">);</span>
 308       <span class="comment">/* we can get the number of channels as the length of any of the value</span>
 309 <span class="comment">       * lists */</span>
 310       list <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;rms&quot;</span><span class="gtkdoc opt">);</span>
 311       channels <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-size">gst_value_list_get_size</a></span> <span class="gtkdoc opt">(</span>list<span class="gtkdoc opt">);</span>
 312
 313       <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;endtime: %&quot;</span> GST_TIME_FORMAT <span class="string">&quot;, channels: %d</span><span class="gtkdoc esc">\n</span><span class="string">&quot;</span><span class="gtkdoc opt">,</span>
 314           <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> channels<span class="gtkdoc opt">);</span>
 315       <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> channels<span class="gtkdoc opt">; ++</span>i<span class="gtkdoc opt">) {</span>
 316         <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;channel %d</span><span class="gtkdoc esc">\n</span><span class="string">&quot;</span><span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
 317         list <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;rms&quot;</span><span class="gtkdoc opt">);</span>
 318         value <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>list<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
 319         rms_dB <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-double">g_value_get_double</a></span> <span class="gtkdoc opt">(</span>value<span class="gtkdoc opt">);</span>
 320         list <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;peak&quot;</span><span class="gtkdoc opt">);</span>
 321         value <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>list<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
 322         peak_dB <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-double">g_value_get_double</a></span> <span class="gtkdoc opt">(</span>value<span class="gtkdoc opt">);</span>
 323         list <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;decay&quot;</span><span class="gtkdoc opt">);</span>
 324         value <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>list<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span>
 325         decay_dB <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-double">g_value_get_double</a></span> <span class="gtkdoc opt">(</span>value<span class="gtkdoc opt">);</span>
 326         <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;    RMS: %f dB, peak: %f dB, decay: %f dB</span><span class="gtkdoc esc">\n</span><span class="string">&quot;</span><span class="gtkdoc opt">,</span>
 327             rms_dB<span class="gtkdoc opt">,</span> peak_dB<span class="gtkdoc opt">,</span> decay_dB<span class="gtkdoc opt">);</span>
 328
 329         <span class="comment">/* converting from dB to normal gives us a value between 0.0 and 1.0 */</span>
 330         rms <span class="gtkdoc opt">=</span> <span class="function">pow</span> <span class="gtkdoc opt">(</span><span class="number">10</span><span class="gtkdoc opt">,</span> rms_dB <span class="gtkdoc opt">/</span> <span class="number">20</span><span class="gtkdoc opt">);</span>
 331         <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;    normalized rms value: %f</span><span class="gtkdoc esc">\n</span><span class="string">&quot;</span><span class="gtkdoc opt">,</span> rms<span class="gtkdoc opt">);</span>
 332       <span class="gtkdoc opt">}</span>
 333     <span class="gtkdoc opt">}</span>
 334   <span class="gtkdoc opt">}</span>
 335   <span class="comment">/* we handled the message we want, and ignored the ones we didn't want.</span>
 336 <span class="comment">   * so the core can unref the message for us */</span>
 337   <span class="keyword">return</span> TRUE<span class="gtkdoc opt">;</span>
 338 <span class="gtkdoc opt">}</span>
 339
 340 <span class="gtkdoc kwb">int</span>
 341 <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>
 342 <span class="gtkdoc opt">{</span>
 343   GstElement <span class="gtkdoc opt">*</span>audiotestsrc<span class="gtkdoc opt">, *</span>audioconvert<span class="gtkdoc opt">, *</span>level<span class="gtkdoc opt">, *</span>fakesink<span class="gtkdoc opt">;</span>
 344   GstElement <span class="gtkdoc opt">*</span>pipeline<span class="gtkdoc opt">;</span>
 345   GstCaps <span class="gtkdoc opt">*</span>caps<span class="gtkdoc opt">;</span>
 346   GstBus <span class="gtkdoc opt">*</span>bus<span class="gtkdoc opt">;</span>
 347   guint watch_id<span class="gtkdoc opt">;</span>
 348   GMainLoop <span class="gtkdoc opt">*</span>loop<span class="gtkdoc opt">;</span>
 349
 350   <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>
 351
 352   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-from-string">gst_caps_from_string</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;audio/x-raw-int,channels=2&quot;</span><span class="gtkdoc opt">);</span>
 353
 354   pipeline <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>NULL<span class="gtkdoc opt">);</span>
 355   <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>pipeline<span class="gtkdoc opt">);</span>
 356   audiotestsrc <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> NULL<span class="gtkdoc opt">);</span>
 357   <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>audiotestsrc<span class="gtkdoc opt">);</span>
 358   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>
 359   <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>
 360   level <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;level&quot;</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
 361   <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>level<span class="gtkdoc opt">);</span>
 362   fakesink <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> NULL<span class="gtkdoc opt">);</span>
 363   <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>fakesink<span class="gtkdoc opt">);</span>
 364
 365   <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>pipeline<span class="gtkdoc opt">),</span> audiotestsrc<span class="gtkdoc opt">,</span> audioconvert<span class="gtkdoc opt">,</span> level<span class="gtkdoc opt">,</span>
 366       fakesink<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
 367   <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>audiotestsrc<span class="gtkdoc opt">,</span> audioconvert<span class="gtkdoc opt">))</span>
 368     <span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;Failed to link audiotestsrc and audioconvert&quot;</span><span class="gtkdoc opt">);</span>
 369   <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-filtered">gst_element_link_filtered</a></span> <span class="gtkdoc opt">(</span>audioconvert<span class="gtkdoc opt">,</span> level<span class="gtkdoc opt">,</span> caps<span class="gtkdoc opt">))</span>
 370     <span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;Failed to link audioconvert and level&quot;</span><span class="gtkdoc opt">);</span>
 371   <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>level<span class="gtkdoc opt">,</span> fakesink<span class="gtkdoc opt">))</span>
 372     <span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;Failed to link level and fakesink&quot;</span><span class="gtkdoc opt">);</span>
 373
 374   <span class="comment">/* make sure we'll get messages */</span>
 375   <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>level<span class="gtkdoc opt">),</span> <span class="string">&quot;message&quot;</span><span class="gtkdoc opt">,</span> TRUE<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
 376   <span class="comment">/* run synced and not as fast as we can */</span>
 377   <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>fakesink<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>
 378
 379   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>pipeline<span class="gtkdoc opt">);</span>
 380   watch_id <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>
 381
 382   <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>pipeline<span class="gtkdoc opt">,</span> GST_STATE_PLAYING<span class="gtkdoc opt">);</span>
 383
 384   <span class="comment">/* we need to run a GLib main loop to get the messages */</span>
 385   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>
 386   <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>
 387
 388   <span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#g-source-remove">g_source_remove</a></span> <span class="gtkdoc opt">(</span>watch_id<span class="gtkdoc opt">);</span>
 389   <span class="function"><a href="http://library.gnome.org/devel/glib/unstable/glib-The-Main-Event-Loop.html#g-main-loop-unref">g_main_loop_unref</a></span> <span class="gtkdoc opt">(</span>loop<span class="gtkdoc opt">);</span>
 390   <span class="keyword">return</span> <span class="number">0</span><span class="gtkdoc opt">;</span>
 391 <span class="gtkdoc opt">}</span></pre></td>
 392       </tr>
 393     </tbody>
 394   </table>
 395 </div>
 396
 397 </div>
 398 <p>
 399 </p>
 400 <div class="refsynopsisdiv">
 401 <h2>Synopsis</h2>
 402 <div class="refsect2">
 403 <a name="idp17356064"></a><h3>Element Information</h3>
 404 <div class="variablelist"><table border="0">
 405 <col align="left" valign="top">
 406 <tbody>
 407 <tr>
 408 <td><p><span class="term">plugin</span></p></td>
 409 <td>
 410             <a class="link" href="gst-plugins-good-plugins-plugin-level.html#plugin-level">level</a>
 411           </td>
 412 </tr>
 413 <tr>
 414 <td><p><span class="term">author</span></p></td>
 415 <td>Thomas Vander Stichele &lt;thomas at apestaart dot org&gt;</td>
 416 </tr>
 417 <tr>
 418 <td><p><span class="term">class</span></p></td>
 419 <td>Filter/Analyzer/Audio</td>
 420 </tr>
 421 </tbody>
 422 </table></div>
 423 </div>
 424 <hr>
 425 <div class="refsect2">
 426 <a name="idp17817280"></a><h3>Element Pads</h3>
 427 <div class="variablelist"><table border="0">
 428 <col align="left" valign="top">
 429 <tbody>
 430 <tr>
 431 <td><p><span class="term">name</span></p></td>
 432 <td>sink</td>
 433 </tr>
 434 <tr>
 435 <td><p><span class="term">direction</span></p></td>
 436 <td>sink</td>
 437 </tr>
 438 <tr>
 439 <td><p><span class="term">presence</span></p></td>
 440 <td>always</td>
 441 </tr>
 442 <tr>
 443 <td><p><span class="term">details</span></p></td>
 444 <td>audio/x-raw-int, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], endianness=(int)1234, width=(int){ 8, 16, 32 }, depth=(int){ 8, 16, 32 }, signed=(boolean)true</td>
 445 </tr>
 446 <tr>
 447 <td><p><span class="term"></span></p></td>
 448 <td> audio/x-raw-float, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], endianness=(int)1234, width=(int){ 32, 64 }</td>
 449 </tr>
 450 </tbody>
 451 </table></div>
 452 <div class="variablelist"><table border="0">
 453 <col align="left" valign="top">
 454 <tbody>
 455 <tr>
 456 <td><p><span class="term">name</span></p></td>
 457 <td>src</td>
 458 </tr>
 459 <tr>
 460 <td><p><span class="term">direction</span></p></td>
 461 <td>source</td>
 462 </tr>
 463 <tr>
 464 <td><p><span class="term">presence</span></p></td>
 465 <td>always</td>
 466 </tr>
 467 <tr>
 468 <td><p><span class="term">details</span></p></td>
 469 <td>audio/x-raw-int, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], endianness=(int)1234, width=(int){ 8, 16, 32 }, depth=(int){ 8, 16, 32 }, signed=(boolean)true</td>
 470 </tr>
 471 <tr>
 472 <td><p><span class="term"></span></p></td>
 473 <td> audio/x-raw-float, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], endianness=(int)1234, width=(int){ 32, 64 }</td>
 474 </tr>
 475 </tbody>
 476 </table></div>
 477 </div>
 478 </div>
 479 <p>
 480 </p>
 481 </div>
 482 <div class="refsect1">
 483 <a name="gst-plugins-good-plugins-level.details"></a><h2>Details</h2>
 484 <div class="refsect2">
 485 <a name="GstLevel-struct"></a><h3>struct GstLevel</h3>
 486 <pre class="programlisting">struct GstLevel;</pre>
 487 <p>
 488 Opaque data structure.
 489 </p>
 490 </div>
 491 </div>
 492 <div class="refsect1">
 493 <a name="gst-plugins-good-plugins-level.property-details"></a><h2>Property Details</h2>
 494 <div class="refsect2">
 495 <a name="GstLevel--interval"></a><h3>The <code class="literal">"interval"</code> property</h3>
 496 <pre class="programlisting">  "interval"                 <span class="type">guint64</span>               : Read / Write</pre>
 497 <p>Interval of time between message posts (in nanoseconds).</p>
 498 <p>Allowed values: &gt;= 1</p>
 499 <p>Default value: 100000000</p>
 500 </div>
 501 <hr>
 502 <div class="refsect2">
 503 <a name="GstLevel--message"></a><h3>The <code class="literal">"message"</code> property</h3>
 504 <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>
 505 <p>Post a level message for each passed interval.</p>
 506 <p>Default value: TRUE</p>
 507 </div>
 508 <hr>
 509 <div class="refsect2">
 510 <a name="GstLevel--peak-falloff"></a><h3>The <code class="literal">"peak-falloff"</code> property</h3>
 511 <pre class="programlisting">  "peak-falloff"             <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a>               : Read / Write</pre>
 512 <p>Decay rate of decay peak after TTL (in dB/sec).</p>
 513 <p>Allowed values: &gt;= 0</p>
 514 <p>Default value: 10</p>
 515 </div>
 516 <hr>
 517 <div class="refsect2">
 518 <a name="GstLevel--peak-ttl"></a><h3>The <code class="literal">"peak-ttl"</code> property</h3>
 519 <pre class="programlisting">  "peak-ttl"                 <span class="type">guint64</span>               : Read / Write</pre>
 520 <p>Time To Live of decay peak before it falls back (in nanoseconds).</p>
 521 <p>Default value: 300000000</p>
 522 </div>
 523 </div>
 524 </div>
 525 <div class="footer">
 526 <hr>
 527           Generated by GTK-Doc V1.18</div>
 528 </body>
 529 </html>