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: GStreamer Good Plugins 1.0 Plugins Reference Manual</title> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="index.html" title="GStreamer Good Plugins 1.0 Plugins Reference Manual"> 8<link rel="up" href="ch01.html" title="gst-plugins-good Elements"> 9<link rel="prev" href="gst-plugins-good-plugins-lamemp3enc.html" title="lamemp3enc"> 10<link rel="next" href="gst-plugins-good-plugins-matroskademux.html" title="matroskademux"> 11<meta name="generator" content="GTK-Doc V1.28 (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="5"><tr valign="middle"> 16<td width="100%" align="left" class="shortcuts"> 17<a href="#" class="shortcut">Top</a><span id="nav_description"> <span class="dim">|</span> 18 <a href="#gst-plugins-good-plugins-level.description" class="shortcut">Description</a></span><span id="nav_hierarchy"> <span class="dim">|</span> 19 <a href="#gst-plugins-good-plugins-level.object-hierarchy" class="shortcut">Object Hierarchy</a></span><span id="nav_properties"> <span class="dim">|</span> 20 <a href="#gst-plugins-good-plugins-level.properties" class="shortcut">Properties</a></span> 21</td> 22<td><a accesskey="h" href="index.html"><img src="home.png" width="16" height="16" border="0" alt="Home"></a></td> 23<td><a accesskey="u" href="ch01.html"><img src="up.png" width="16" height="16" border="0" alt="Up"></a></td> 24<td><a accesskey="p" href="gst-plugins-good-plugins-lamemp3enc.html"><img src="left.png" width="16" height="16" border="0" alt="Prev"></a></td> 25<td><a accesskey="n" href="gst-plugins-good-plugins-matroskademux.html"><img src="right.png" width="16" height="16" border="0" alt="Next"></a></td> 26</tr></table> 27<div class="refentry"> 28<a name="gst-plugins-good-plugins-level"></a><div class="titlepage"></div> 29<div class="refnamediv"><table width="100%"><tr> 30<td valign="top"> 31<h2><span class="refentrytitle"><a name="gst-plugins-good-plugins-level.top_of_page"></a>level</span></h2> 32<p>level</p> 33</td> 34<td class="gallery_image" valign="top" align="right"></td> 35</tr></table></div> 36<div class="refsect1"> 37<a name="gst-plugins-good-plugins-level.properties"></a><h2>Properties</h2> 38<div class="informaltable"><table class="informaltable" border="0"> 39<colgroup> 40<col width="150px" class="properties_type"> 41<col width="300px" class="properties_name"> 42<col width="200px" class="properties_flags"> 43</colgroup> 44<tbody> 45<tr> 46<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint64"><span class="type">guint64</span></a></td> 47<td class="property_name"><a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--interval" title="The “interval” property">interval</a></td> 48<td class="property_flags">Read / Write</td> 49</tr> 50<tr> 51<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td> 52<td class="property_name"><a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--message" title="The “message” property">message</a></td> 53<td class="property_flags">Read / Write</td> 54</tr> 55<tr> 56<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a></td> 57<td class="property_name"><a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-falloff" title="The “peak-falloff” property">peak-falloff</a></td> 58<td class="property_flags">Read / Write</td> 59</tr> 60<tr> 61<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint64"><span class="type">guint64</span></a></td> 62<td class="property_name"><a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-ttl" title="The “peak-ttl” property">peak-ttl</a></td> 63<td class="property_flags">Read / Write</td> 64</tr> 65<tr> 66<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td> 67<td class="property_name"><a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--post-messages" title="The “post-messages” property">post-messages</a></td> 68<td class="property_flags">Read / Write</td> 69</tr> 70</tbody> 71</table></div> 72</div> 73<a name="GstLevel"></a><div class="refsect1"> 74<a name="gst-plugins-good-plugins-level.other"></a><h2>Types and Values</h2> 75<div class="informaltable"><table class="informaltable" width="100%" border="0"> 76<colgroup> 77<col width="150px" class="name"> 78<col class="description"> 79</colgroup> 80<tbody><tr> 81<td class="datatype_keyword">struct</td> 82<td class="function_name"><a class="link" href="gst-plugins-good-plugins-level.html#GstLevel-struct" title="struct GstLevel">GstLevel</a></td> 83</tr></tbody> 84</table></div> 85</div> 86<div class="refsect1"> 87<a name="gst-plugins-good-plugins-level.object-hierarchy"></a><h2>Object Hierarchy</h2> 88<pre class="screen"> <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject-struct">GObject</a> 89 <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a> 90 <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstObject.html#GstObject-struct">GstObject</a> 91 <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElement.html#GstElement-struct">GstElement</a> 92 <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-libs-1.0/GstBaseTransform.html#GstBaseTransform-struct">GstBaseTransform</a> 93 <span class="lineart">╰──</span> GstLevel 94</pre> 95</div> 96<div class="refsect1"> 97<a name="gst-plugins-good-plugins-level.description"></a><h2>Description</h2> 98<p>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 99is <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>, generates an element message named</p> 100<code class="classname">"level"</code>: 101<p>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. 102The message's structure contains these fields:</p> 103<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 104<li class="listitem"><p> 105 <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> 106 <code class="classname">"timestamp"</code>: 107 the timestamp of the buffer that triggered the message. 108 </p></li> 109<li class="listitem"><p> 110 <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> 111 <code class="classname">"stream-time"</code>: 112 the stream time of the buffer. 113 </p></li> 114<li class="listitem"><p> 115 <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> 116 <code class="classname">"running-time"</code>: 117 the running_time of the buffer. 118 </p></li> 119<li class="listitem"><p> 120 <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> 121 <code class="classname">"duration"</code>: 122 the duration of the buffer. 123 </p></li> 124<li class="listitem"><p> 125 <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> 126 <code class="classname">"endtime"</code>: 127 the end time of the buffer that triggered the message as stream time (this 128 is deprecated, as it can be calculated from stream-time + duration) 129 </p></li> 130<li class="listitem"><p> 131 <a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#GValueArray-struct"><span class="type">GValueArray</span></a> of <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> 132 <code class="classname">"peak"</code>: 133 the peak power level in dB for each channel 134 </p></li> 135<li class="listitem"><p> 136 <a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#GValueArray-struct"><span class="type">GValueArray</span></a> of <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> 137 <code class="classname">"decay"</code>: 138 the decaying peak power level in dB for each channel 139 The decaying peak level follows the peak level, but starts dropping if no 140 new peak is reached after the time given by the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-ttl" title="The “peak-ttl” property"><span class="type">“peak-ttl”</span></a>. 141 When the decaying peak level drops, it does so at the decay rate as 142 specified by the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--peak-falloff" title="The “peak-falloff” property"><span class="type">“peak-falloff”</span></a>. 143 </p></li> 144<li class="listitem"><p> 145 <a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#GValueArray-struct"><span class="type">GValueArray</span></a> of <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> 146 <code class="classname">"rms"</code>: 147 the Root Mean Square (or average power) level in dB for each channel 148 </p></li> 149</ul></div> 150<div class="refsect2"> 151<a name="id-1.2.87.7.6"></a><h3>Example application</h3> 152<div class="informalexample"> 153 <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> 154 <tbody> 155 <tr> 156 <td class="listing_lines" align="right"><pre>1 1572 1583 1594 1605 1616 1627 1638 1649 16510 16611 16712 16813 16914 17015 17116 17217 17318 17419 17520 17621 17722 17823 17924 18025 18126 18227 18328 18429 18530 18631 18732 18833 18934 19035 19136 19237 19338 19439 19540 19641 19742 19843 19944 20045 20146 20247 20348 20449 20550 20651 20752 20853 20954 21055 21156 21257 21358 21459 21560 21661 21762 21863 21964 22065 22166 22267 22368 22469 22570 22671 22772 22873 22974 23075 23176 23277 23378 23479 23580 23681 23782 23883 23984 24085 24186 24287 24388 24489 24590 24691 24792 24893 24994 25095 25196 25297 25398 25499 255100 256101 257102 258103 259104 260105 261106 262107 263108 264109 265110 266111 267112 268113 269114 270115 271116 272117 273118 274119 275120 276121 277122 278123 279124 280125 281126 282127 283128 284129 285130 286131 287132 288133 289134 290135 291136 292137 293138 294139 295140</pre></td> 296 <td class="listing_code"><pre class="programlisting"><span class="comment">/* GStreamer</span> 297<span class="comment"> * Copyright (C) 2000,2001,2002,2003,2005</span> 298<span class="comment"> * Thomas Vander Stichele <thomas at apestaart dot org></span> 299<span class="comment"> *</span> 300<span class="comment"> * This library is free software; you can redistribute it and/or</span> 301<span class="comment"> * modify it under the terms of the GNU Library General Public</span> 302<span class="comment"> * License as published by the Free Software Foundation; either</span> 303<span class="comment"> * version 2 of the License, or (at your option) any later version.</span> 304<span class="comment"> *</span> 305<span class="comment"> * This library is distributed in the hope that it will be useful,</span> 306<span class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</span> 307<span class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</span> 308<span class="comment"> * Library General Public License for more details.</span> 309<span class="comment"> *</span> 310<span class="comment"> * You should have received a copy of the GNU Library General Public</span> 311<span class="comment"> * License along with this library; if not, write to the</span> 312<span class="comment"> * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,</span> 313<span class="comment"> * Boston, MA 02110-1301, USA.</span> 314<span class="comment"> */</span> 315 316<span class="gtkdoc ppc">#include <string.h></span> 317<span class="gtkdoc ppc">#include <math.h></span> 318 319<span class="gtkdoc ppc">#define GLIB_DISABLE_DEPRECATION_WARNINGS</span> 320 321<span class="gtkdoc ppc">#include <gst/gst.h></span> 322 323<span class="gtkdoc kwb">static</span> gboolean 324<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> 325<span class="gtkdoc opt">{</span> 326 327 <span class="keyword">if</span> <span class="gtkdoc opt">(</span>message<span class="gtkdoc opt">-></span>type <span class="gtkdoc opt">==</span> GST_MESSAGE_ELEMENT<span class="gtkdoc opt">) {</span> 328 <span class="gtkdoc kwb">const</span> GstStructure <span class="gtkdoc opt">*</span>s <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstMessage.html#gst-message-get-structure">gst_message_get_structure</a></span> <span class="gtkdoc opt">(</span>message<span class="gtkdoc opt">);</span> 329 <span class="gtkdoc kwb">const</span> gchar <span class="gtkdoc opt">*</span>name <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstStructure.html#gst-structure-get-name">gst_structure_get_name</a></span> <span class="gtkdoc opt">(</span>s<span class="gtkdoc opt">);</span> 330 331 <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">"level"</span><span class="gtkdoc opt">) ==</span> <span class="number">0</span><span class="gtkdoc opt">) {</span> 332 gint channels<span class="gtkdoc opt">;</span> 333 GstClockTime endtime<span class="gtkdoc opt">;</span> 334 gdouble rms_dB<span class="gtkdoc opt">,</span> peak_dB<span class="gtkdoc opt">,</span> decay_dB<span class="gtkdoc opt">;</span> 335 gdouble rms<span class="gtkdoc opt">;</span> 336 <span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>array_val<span class="gtkdoc opt">;</span> 337 <span class="gtkdoc kwb">const</span> GValue <span class="gtkdoc opt">*</span>value<span class="gtkdoc opt">;</span> 338 GValueArray <span class="gtkdoc opt">*</span>rms_arr<span class="gtkdoc opt">, *</span>peak_arr<span class="gtkdoc opt">, *</span>decay_arr<span class="gtkdoc opt">;</span> 339 gint i<span class="gtkdoc opt">;</span> 340 341 <span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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">"endtime"</span><span class="gtkdoc opt">, &</span>endtime<span class="gtkdoc opt">))</span> 342 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Message-Logging.html#g-warning">g_warning</a></span> <span class="gtkdoc opt">(</span><span class="string">"Could not parse endtime"</span><span class="gtkdoc opt">);</span> 343 344 <span class="comment">/* the values are packed into GValueArrays with the value per channel */</span> 345 array_val <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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">"rms"</span><span class="gtkdoc opt">);</span> 346 rms_arr <span class="gtkdoc opt">= (</span>GValueArray <span class="gtkdoc opt">*)</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-boxed">g_value_get_boxed</a></span> <span class="gtkdoc opt">(</span>array_val<span class="gtkdoc opt">);</span> 347 348 array_val <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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">"peak"</span><span class="gtkdoc opt">);</span> 349 peak_arr <span class="gtkdoc opt">= (</span>GValueArray <span class="gtkdoc opt">*)</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-boxed">g_value_get_boxed</a></span> <span class="gtkdoc opt">(</span>array_val<span class="gtkdoc opt">);</span> 350 351 array_val <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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">"decay"</span><span class="gtkdoc opt">);</span> 352 decay_arr <span class="gtkdoc opt">= (</span>GValueArray <span class="gtkdoc opt">*)</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Standard-Parameter-and-Value-Types.html#g-value-get-boxed">g_value_get_boxed</a></span> <span class="gtkdoc opt">(</span>array_val<span class="gtkdoc opt">);</span> 353 354 <span class="comment">/* we can get the number of channels as the length of any of the value</span> 355<span class="comment"> * arrays */</span> 356 channels <span class="gtkdoc opt">=</span> rms_arr<span class="gtkdoc opt">-></span>n_values<span class="gtkdoc opt">;</span> 357 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">"endtime: %"</span> GST_TIME_FORMAT <span class="string">", channels: %d</span><span class="gtkdoc esc">\n</span><span class="string">"</span><span class="gtkdoc opt">,</span> 358 <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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> 359 <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"><</span> channels<span class="gtkdoc opt">; ++</span>i<span class="gtkdoc opt">) {</span> 360 361 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">"channel %d</span><span class="gtkdoc esc">\n</span><span class="string">"</span><span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span> 362 value <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#g-value-array-get-nth">g_value_array_get_nth</a></span> <span class="gtkdoc opt">(</span>rms_arr<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span> 363 rms_dB <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/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> 364 365 value <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#g-value-array-get-nth">g_value_array_get_nth</a></span> <span class="gtkdoc opt">(</span>peak_arr<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span> 366 peak_dB <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/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> 367 368 value <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#g-value-array-get-nth">g_value_array_get_nth</a></span> <span class="gtkdoc opt">(</span>decay_arr<span class="gtkdoc opt">,</span> i<span class="gtkdoc opt">);</span> 369 decay_dB <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/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> 370 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">" RMS: %f dB, peak: %f dB, decay: %f dB</span><span class="gtkdoc esc">\n</span><span class="string">"</span><span class="gtkdoc opt">,</span> 371 rms_dB<span class="gtkdoc opt">,</span> peak_dB<span class="gtkdoc opt">,</span> decay_dB<span class="gtkdoc opt">);</span> 372 373 <span class="comment">/* converting from dB to normal gives us a value between 0.0 and 1.0 */</span> 374 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> 375 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Warnings-and-Assertions.html#g-print">g_print</a></span> <span class="gtkdoc opt">(</span><span class="string">" normalized rms value: %f</span><span class="gtkdoc esc">\n</span><span class="string">"</span><span class="gtkdoc opt">,</span> rms<span class="gtkdoc opt">);</span> 376 <span class="gtkdoc opt">}</span> 377 <span class="gtkdoc opt">}</span> 378 <span class="gtkdoc opt">}</span> 379 <span class="comment">/* we handled the message we want, and ignored the ones we didn't want.</span> 380<span class="comment"> * so the core can unref the message for us */</span> 381 <span class="keyword">return</span> TRUE<span class="gtkdoc opt">;</span> 382<span class="gtkdoc opt">}</span> 383 384<span class="gtkdoc kwb">int</span> 385<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> 386<span class="gtkdoc opt">{</span> 387 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> 388 GstElement <span class="gtkdoc opt">*</span>pipeline<span class="gtkdoc opt">;</span> 389 GstCaps <span class="gtkdoc opt">*</span>caps<span class="gtkdoc opt">;</span> 390 GstBus <span class="gtkdoc opt">*</span>bus<span class="gtkdoc opt">;</span> 391 guint watch_id<span class="gtkdoc opt">;</span> 392 GMainLoop <span class="gtkdoc opt">*</span>loop<span class="gtkdoc opt">;</span> 393 394 <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/gstreamer-Gst.html#gst-init">gst_init</a></span> <span class="gtkdoc opt">(&</span>argc<span class="gtkdoc opt">, &</span>argv<span class="gtkdoc opt">);</span> 395 396 caps <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstCaps.html#gst-caps-from-string">gst_caps_from_string</a></span> <span class="gtkdoc opt">(</span><span class="string">"audio/x-raw,channels=2"</span><span class="gtkdoc opt">);</span> 397 398 pipeline <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstPipeline.html#gst-pipeline-new">gst_pipeline_new</a></span> <span class="gtkdoc opt">(</span>NULL<span class="gtkdoc opt">);</span> 399 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">);</span> 400 audiotestsrc <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">"audiotestsrc"</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span> 401 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>audiotestsrc<span class="gtkdoc opt">);</span> 402 audioconvert <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">"audioconvert"</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span> 403 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>audioconvert<span class="gtkdoc opt">);</span> 404 level <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">"level"</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span> 405 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>level<span class="gtkdoc opt">);</span> 406 fakesink <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">"fakesink"</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span> 407 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Testing.html#g-assert">g_assert</a></span> <span class="gtkdoc opt">(</span>fakesink<span class="gtkdoc opt">);</span> 408 409 <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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> 410 fakesink<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span> 411 <span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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> 412 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">"Failed to link audiotestsrc and audioconvert"</span><span class="gtkdoc opt">);</span> 413 <span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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> 414 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">"Failed to link audioconvert and level"</span><span class="gtkdoc opt">);</span> 415 <span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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> 416 <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">"Failed to link level and fakesink"</span><span class="gtkdoc opt">);</span> 417 418 <span class="comment">/* make sure we'll get messages */</span> 419 <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gobject/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">"post-messages"</span><span class="gtkdoc opt">,</span> TRUE<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span> 420 <span class="comment">/* run synced and not as fast as we can */</span> 421 <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gobject/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">"sync"</span><span class="gtkdoc opt">,</span> TRUE<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span> 422 423 bus <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElement.html#gst-element-get-bus">gst_element_get_bus</a></span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">);</span> 424 watch_id <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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> 425 426 <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/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> 427 428 <span class="comment">/* we need to run a GLib main loop to get the messages */</span> 429 loop <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/glib/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> 430 <span class="function"><a href="/usr/share/gtk-doc/html/glib/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> 431 432 <span class="function"><a href="/usr/share/gtk-doc/html/glib/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> 433 <span class="function"><a href="/usr/share/gtk-doc/html/glib/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> 434 <span class="keyword">return</span> <span class="number">0</span><span class="gtkdoc opt">;</span> 435<span class="gtkdoc opt">}</span></pre></td> 436 </tr> 437 </tbody> 438 </table> 439</div> 440 441</div> 442<div class="refsynopsisdiv"> 443<h2>Synopsis</h2> 444<div class="refsect2"> 445<a name="id-1.2.87.7.7.1"></a><h3>Element Information</h3> 446<div class="variablelist"><table border="0" class="variablelist"> 447<colgroup> 448<col align="left" valign="top"> 449<col> 450</colgroup> 451<tbody> 452<tr> 453<td><p><span class="term">plugin</span></p></td> 454<td> 455 <a class="link" href="gst-plugins-good-plugins-plugin-level.html#plugin-level">level</a> 456 </td> 457</tr> 458<tr> 459<td><p><span class="term">author</span></p></td> 460<td>Thomas Vander Stichele <thomas at apestaart dot org></td> 461</tr> 462<tr> 463<td><p><span class="term">class</span></p></td> 464<td>Filter/Analyzer/Audio</td> 465</tr> 466</tbody> 467</table></div> 468</div> 469<hr> 470<div class="refsect2"> 471<a name="id-1.2.87.7.7.2"></a><h3>Element Pads</h3> 472<div class="variablelist"><table border="0" class="variablelist"> 473<colgroup> 474<col align="left" valign="top"> 475<col> 476</colgroup> 477<tbody> 478<tr> 479<td><p><span class="term">name</span></p></td> 480<td>sink</td> 481</tr> 482<tr> 483<td><p><span class="term">direction</span></p></td> 484<td>sink</td> 485</tr> 486<tr> 487<td><p><span class="term">presence</span></p></td> 488<td>always</td> 489</tr> 490<tr> 491<td><p><span class="term">details</span></p></td> 492<td>audio/x-raw, format=(string){ S8, S16LE, S32LE, F32LE, F64LE }, layout=(string)interleaved, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td> 493</tr> 494</tbody> 495</table></div> 496<div class="variablelist"><table border="0" class="variablelist"> 497<colgroup> 498<col align="left" valign="top"> 499<col> 500</colgroup> 501<tbody> 502<tr> 503<td><p><span class="term">name</span></p></td> 504<td>src</td> 505</tr> 506<tr> 507<td><p><span class="term">direction</span></p></td> 508<td>source</td> 509</tr> 510<tr> 511<td><p><span class="term">presence</span></p></td> 512<td>always</td> 513</tr> 514<tr> 515<td><p><span class="term">details</span></p></td> 516<td>audio/x-raw, format=(string){ S8, S16LE, S32LE, F32LE, F64LE }, layout=(string)interleaved, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td> 517</tr> 518</tbody> 519</table></div> 520</div> 521</div> 522</div> 523<div class="refsect1"> 524<a name="gst-plugins-good-plugins-level.functions_details"></a><h2>Functions</h2> 525<p></p> 526</div> 527<div class="refsect1"> 528<a name="gst-plugins-good-plugins-level.other_details"></a><h2>Types and Values</h2> 529<div class="refsect2"> 530<a name="GstLevel-struct"></a><h3>struct GstLevel</h3> 531<pre class="programlisting">struct GstLevel;</pre> 532<p>Opaque data structure.</p> 533</div> 534</div> 535<div class="refsect1"> 536<a name="gst-plugins-good-plugins-level.property-details"></a><h2>Property Details</h2> 537<div class="refsect2"> 538<a name="GstLevel--interval"></a><h3>The <code class="literal">“interval”</code> property</h3> 539<pre class="programlisting"> “interval” <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint64"><span class="type">guint64</span></a></pre> 540<p>Interval of time between message posts (in nanoseconds).</p> 541<p>Flags: Read / Write</p> 542<p>Allowed values: >= 1</p> 543<p>Default value: 100000000</p> 544</div> 545<hr> 546<div class="refsect2"> 547<a name="GstLevel--message"></a><h3>The <code class="literal">“message”</code> property</h3> 548<pre class="programlisting"> “message” <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre> 549<p>Post a 'level' message for each passed interval (deprecated, use the post-messages property instead).</p> 550<p>Flags: Read / Write</p> 551<p>Default value: TRUE</p> 552</div> 553<hr> 554<div class="refsect2"> 555<a name="GstLevel--peak-falloff"></a><h3>The <code class="literal">“peak-falloff”</code> property</h3> 556<pre class="programlisting"> “peak-falloff” <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a></pre> 557<p>Decay rate of decay peak after TTL (in dB/sec).</p> 558<p>Flags: Read / Write</p> 559<p>Allowed values: >= 0</p> 560<p>Default value: 10</p> 561</div> 562<hr> 563<div class="refsect2"> 564<a name="GstLevel--peak-ttl"></a><h3>The <code class="literal">“peak-ttl”</code> property</h3> 565<pre class="programlisting"> “peak-ttl” <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint64"><span class="type">guint64</span></a></pre> 566<p>Time To Live of decay peak before it falls back (in nanoseconds).</p> 567<p>Flags: Read / Write</p> 568<p>Default value: 300000000</p> 569</div> 570<hr> 571<div class="refsect2"> 572<a name="GstLevel--post-messages"></a><h3>The <code class="literal">“post-messages”</code> property</h3> 573<pre class="programlisting"> “post-messages” <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre> 574<p>Post messages on the bus with level information.</p> 575<div class="warning"> 576<p><code class="literal">GstLevel:post-messages</code> is deprecated and should not be used in newly-written code.</p> 577<p>use the <a class="link" href="gst-plugins-good-plugins-level.html#GstLevel--post-messages" title="The “post-messages” property"><span class="type">“post-messages”</span></a> property</p> 578</div> 579<p>Flags: Read / Write</p> 580<p>Default value: TRUE</p> 581<p class="since">Since: 1.1.0</p> 582</div> 583</div> 584</div> 585<div class="footer"> 586<hr>Generated by GTK-Doc V1.28</div> 587</body> 588</html>
