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

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  24 <a href="#gst-plugins-good-plugins-audiocheblimit.synopsis" class="shortcut">Top</a>
  25                    |
  26                   <a href="#gst-plugins-good-plugins-audiocheblimit.description" class="shortcut">Description</a>
  27                    |
  28                   <a href="#gst-plugins-good-plugins-audiocheblimit.object-hierarchy" class="shortcut">Object Hierarchy</a>
  29                    |
  30                   <a href="#gst-plugins-good-plugins-audiocheblimit.properties" class="shortcut">Properties</a>
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  33 <div class="refentry">
  34 <a name="gst-plugins-good-plugins-audiocheblimit"></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-audiocheblimit.top_of_page"></a>audiocheblimit</span></h2>
  38 <p>audiocheblimit — Chebyshev low pass and high pass filter</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-audiocheblimit.synopsis"></a><h2>Synopsis</h2>
  44 <a name="GstAudioChebLimit"></a><pre class="synopsis">struct              <a class="link" href="gst-plugins-good-plugins-audiocheblimit.html#GstAudioChebLimit-struct" title="struct GstAudioChebLimit">GstAudioChebLimit</a>;
  45 </pre>
  46 </div>
  47 <div class="refsect1">
  48 <a name="gst-plugins-good-plugins-audiocheblimit.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                            +----GstAudioFXBaseIIRFilter
  56                                  +----GstAudioChebLimit
  57 </pre>
  58 </div>
  59 <div class="refsect1">
  60 <a name="gst-plugins-good-plugins-audiocheblimit.properties"></a><h2>Properties</h2>
  61 <pre class="synopsis">
  62   "<a class="link" href="gst-plugins-good-plugins-audiocheblimit.html#GstAudioChebLimit--cutoff" title='The "cutoff" property'>cutoff</a>"                   <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gfloat"><span class="type">gfloat</span></a>                : Read / Write
  63   "<a class="link" href="gst-plugins-good-plugins-audiocheblimit.html#GstAudioChebLimit--mode" title='The "mode" property'>mode</a>"                     <span class="type">GstAudioChebLimitMode</span>  : Read / Write
  64   "<a class="link" href="gst-plugins-good-plugins-audiocheblimit.html#GstAudioChebLimit--poles" title='The "poles" property'>poles</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-audiocheblimit.html#GstAudioChebLimit--ripple" title='The "ripple" property'>ripple</a>"                   <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gfloat"><span class="type">gfloat</span></a>                : Read / Write
  66   "<a class="link" href="gst-plugins-good-plugins-audiocheblimit.html#GstAudioChebLimit--type" title='The "type" property'>type</a>"                     <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write
  67 </pre>
  68 </div>
  69 <div class="refsect1">
  70 <a name="gst-plugins-good-plugins-audiocheblimit.description"></a><h2>Description</h2>
  71 <p>
  72 Attenuates all frequencies above the cutoff frequency (low-pass) or all frequencies below the
  73 cutoff frequency (high-pass). The number of poles and the ripple parameter control the rolloff.
  74 </p>
  75 <p>
  76 This element has the advantage over the windowed sinc lowpass and highpass filter that it is
  77 much faster and produces almost as good results. It's only disadvantages are the highly
  78 non-linear phase and the slower rolloff compared to a windowed sinc filter with a large kernel.
  79 </p>
  80 <p>
  81 For type 1 the ripple parameter specifies how much ripple in dB is allowed in the passband, i.e.
  82 some frequencies in the passband will be amplified by that value. A higher ripple value will allow
  83 a faster rolloff.
  84 </p>
  85 <p>
  86 For type 2 the ripple parameter specifies the stopband attenuation. In the stopband the gain will
  87 be at most this value. A lower ripple value will allow a faster rolloff.
  88 </p>
  89 <p>
  90 As a special case, a Chebyshev type 1 filter with no ripple is a Butterworth filter.
  91 </p>
  92 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
  93 <h3 class="title">Note</h3>
  94 <p>
  95 Be warned that a too large number of poles can produce noise. The most poles are possible with
  96 a cutoff frequency at a quarter of the sampling rate.
  97 </p>
  98 </div>
  99 <p>
 100 </p>
 101 <div class="refsect2">
 102 <a name="idp10638224"></a><h3>Example launch line</h3>
 103 <div class="informalexample">
 104   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 105     <tbody>
 106       <tr>
 107         <td class="listing_lines" align="right"><pre>1
 108 2
 109 3</pre></td>
 110         <td class="listing_code"><pre class="programlisting">gst<span class="gtkdoc opt">-</span>launch audiotestsrc freq<span class="gtkdoc opt">=</span><span class="number">1500</span> <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> audiocheblimit mode<span class="gtkdoc opt">=</span>low<span class="gtkdoc opt">-</span>pass cutoff<span class="gtkdoc opt">=</span><span class="number">1000</span> poles<span class="gtkdoc opt">=</span><span class="number">4</span> <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> alsasink
 111 gst<span class="gtkdoc opt">-</span>launch filesrc location<span class="gtkdoc opt">=</span><span class="string">&quot;melo1.ogg&quot;</span> <span class="gtkdoc opt">!</span> oggdemux <span class="gtkdoc opt">!</span> vorbisdec <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> audiocheblimit mode<span class="gtkdoc opt">=</span>high<span class="gtkdoc opt">-</span>pass cutoff<span class="gtkdoc opt">=</span><span class="number">400</span> ripple<span class="gtkdoc opt">=</span><span class="number">0.2</span> <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> alsasink
 112 gst<span class="gtkdoc opt">-</span>launch audiotestsrc wave<span class="gtkdoc opt">=</span>white<span class="gtkdoc opt">-</span>noise <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> audiocheblimit mode<span class="gtkdoc opt">=</span>low<span class="gtkdoc opt">-</span>pass cutoff<span class="gtkdoc opt">=</span><span class="number">800</span> type<span class="gtkdoc opt">=</span><span class="number">2</span> <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> alsasink</pre></td>
 113       </tr>
 114     </tbody>
 115   </table>
 116 </div>
 117
 118 </div>
 119 <p>
 120 </p>
 121 <div class="refsynopsisdiv">
 122 <h2>Synopsis</h2>
 123 <div class="refsect2">
 124 <a name="idp7437440"></a><h3>Element Information</h3>
 125 <div class="variablelist"><table border="0">
 126 <col align="left" valign="top">
 127 <tbody>
 128 <tr>
 129 <td><p><span class="term">plugin</span></p></td>
 130 <td>
 131             <a class="link" href="gst-plugins-good-plugins-plugin-audiofx.html#plugin-audiofx">audiofx</a>
 132           </td>
 133 </tr>
 134 <tr>
 135 <td><p><span class="term">author</span></p></td>
 136 <td>Sebastian Dröge &lt;sebastian.droege@collabora.co.uk&gt;</td>
 137 </tr>
 138 <tr>
 139 <td><p><span class="term">class</span></p></td>
 140 <td>Filter/Effect/Audio</td>
 141 </tr>
 142 </tbody>
 143 </table></div>
 144 </div>
 145 <hr>
 146 <div class="refsect2">
 147 <a name="idp7776880"></a><h3>Element Pads</h3>
 148 <div class="variablelist"><table border="0">
 149 <col align="left" valign="top">
 150 <tbody>
 151 <tr>
 152 <td><p><span class="term">name</span></p></td>
 153 <td>sink</td>
 154 </tr>
 155 <tr>
 156 <td><p><span class="term">direction</span></p></td>
 157 <td>sink</td>
 158 </tr>
 159 <tr>
 160 <td><p><span class="term">presence</span></p></td>
 161 <td>always</td>
 162 </tr>
 163 <tr>
 164 <td><p><span class="term">details</span></p></td>
 165 <td>audio/x-raw-float, width=(int){ 32, 64 }, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 166 </tr>
 167 </tbody>
 168 </table></div>
 169 <div class="variablelist"><table border="0">
 170 <col align="left" valign="top">
 171 <tbody>
 172 <tr>
 173 <td><p><span class="term">name</span></p></td>
 174 <td>src</td>
 175 </tr>
 176 <tr>
 177 <td><p><span class="term">direction</span></p></td>
 178 <td>source</td>
 179 </tr>
 180 <tr>
 181 <td><p><span class="term">presence</span></p></td>
 182 <td>always</td>
 183 </tr>
 184 <tr>
 185 <td><p><span class="term">details</span></p></td>
 186 <td>audio/x-raw-float, width=(int){ 32, 64 }, endianness=(int)1234, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]</td>
 187 </tr>
 188 </tbody>
 189 </table></div>
 190 </div>
 191 </div>
 192 <p>
 193 </p>
 194 </div>
 195 <div class="refsect1">
 196 <a name="gst-plugins-good-plugins-audiocheblimit.details"></a><h2>Details</h2>
 197 <div class="refsect2">
 198 <a name="GstAudioChebLimit-struct"></a><h3>struct GstAudioChebLimit</h3>
 199 <pre class="programlisting">struct GstAudioChebLimit;</pre>
 200 <p>
 201 </p>
 202 </div>
 203 </div>
 204 <div class="refsect1">
 205 <a name="gst-plugins-good-plugins-audiocheblimit.property-details"></a><h2>Property Details</h2>
 206 <div class="refsect2">
 207 <a name="GstAudioChebLimit--cutoff"></a><h3>The <code class="literal">"cutoff"</code> property</h3>
 208 <pre class="programlisting">  "cutoff"                   <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gfloat"><span class="type">gfloat</span></a>                : Read / Write</pre>
 209 <p>Cut off frequency (Hz).</p>
 210 <p>Allowed values: [0,100000]</p>
 211 <p>Default value: 0</p>
 212 </div>
 213 <hr>
 214 <div class="refsect2">
 215 <a name="GstAudioChebLimit--mode"></a><h3>The <code class="literal">"mode"</code> property</h3>
 216 <pre class="programlisting">  "mode"                     <span class="type">GstAudioChebLimitMode</span>  : Read / Write</pre>
 217 <p>Low pass or high pass mode.</p>
 218 <p>Default value: Low pass (default)</p>
 219 </div>
 220 <hr>
 221 <div class="refsect2">
 222 <a name="GstAudioChebLimit--poles"></a><h3>The <code class="literal">"poles"</code> property</h3>
 223 <pre class="programlisting">  "poles"                    <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write</pre>
 224 <p>Number of poles to use, will be rounded up to the next even number.</p>
 225 <p>Allowed values: [2,32]</p>
 226 <p>Default value: 4</p>
 227 </div>
 228 <hr>
 229 <div class="refsect2">
 230 <a name="GstAudioChebLimit--ripple"></a><h3>The <code class="literal">"ripple"</code> property</h3>
 231 <pre class="programlisting">  "ripple"                   <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gfloat"><span class="type">gfloat</span></a>                : Read / Write</pre>
 232 <p>Amount of ripple (dB).</p>
 233 <p>Allowed values: [0,200]</p>
 234 <p>Default value: 0.25</p>
 235 </div>
 236 <hr>
 237 <div class="refsect2">
 238 <a name="GstAudioChebLimit--type"></a><h3>The <code class="literal">"type"</code> property</h3>
 239 <pre class="programlisting">  "type"                     <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a>                  : Read / Write</pre>
 240 <p>Type of the chebychev filter.</p>
 241 <p>Allowed values: [1,2]</p>
 242 <p>Default value: 1</p>
 243 </div>
 244 </div>
 245 </div>
 246 <div class="footer">
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