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                   <a href="#GstControlSource.description" class="shortcut">Description</a>
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                   <a href="#GstControlSource.object-hierarchy" class="shortcut">Object Hierarchy</a>
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 <h2><span class="refentrytitle"><a name="GstControlSource.top_of_page"></a>GstControlSource</span></h2>
 <p>GstControlSource — base class for control source sources</p>
 </td>
 <td valign="top" align="right"></td>
 </tr></table></div>
 <div class="refsynopsisdiv">
 <a name="GstControlSource.synopsis"></a><h2>Synopsis</h2>
 <pre class="synopsis">
 #include &lt;gst/gst.h&gt;

                     <a class="link" href="GstControlSource.html#GstValueArray" title="GstValueArray">GstValueArray</a>;
 struct              <a class="link" href="GstControlSource.html#GstControlSource-struct" title="struct GstControlSource">GstControlSource</a>;
 struct              <a class="link" href="GstControlSource.html#GstControlSourceClass" title="struct GstControlSourceClass">GstControlSourceClass</a>;
 <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>            (<a class="link" href="GstControlSource.html#GstControlSourceGetValue" title="GstControlSourceGetValue ()">*GstControlSourceGetValue</a>)         (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *value</code></em>);
 <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>            (<a class="link" href="GstControlSource.html#GstControlSourceGetValueArray" title="GstControlSourceGetValueArray ()">*GstControlSourceGetValueArray</a>)    (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> interval</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> n_values</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *values</code></em>);
 struct              <a class="link" href="GstControlSource.html#GstTimedValue" title="struct GstTimedValue">GstTimedValue</a>;
 <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>            <a class="link" href="GstControlSource.html#gst-control-source-get-value" title="gst_control_source_get_value ()">gst_control_source_get_value</a>        (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *value</code></em>);
 <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>            <a class="link" href="GstControlSource.html#gst-control-source-get-value-array" title="gst_control_source_get_value_array ()">gst_control_source_get_value_array</a>  (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> interval</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> n_values</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *values</code></em>);
 </pre>
 </div>
 <div class="refsect1">
 <a name="GstControlSource.object-hierarchy"></a><h2>Object Hierarchy</h2>
 <pre class="synopsis">
   <a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a>
    +----<a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a>
          +----<a class="link" href="GstObject.html" title="GstObject">GstObject</a>
                +----GstControlSource
 </pre>
 </div>
 <div class="refsect1">
 <a name="GstControlSource.description"></a><h2>Description</h2>
 <p>
 The <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> is a base class for control value sources that could
 be used by <span class="type">GstController</span> to get timestamp-value pairs.
 </p>
 <p>
 A <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> is used by first getting an instance, binding it to a
 <a href="http://library.gnome.org/devel/gobject/unstable/gobject-GParamSpec.html#GParamSpec"><span class="type">GParamSpec</span></a> (for example by using <code class="function">gst_controller_set_control_source()</code>) and
 then by having it used by the <span class="type">GstController</span> or calling
 <a class="link" href="GstControlSource.html#gst-control-source-get-value" title="gst_control_source_get_value ()"><code class="function">gst_control_source_get_value()</code></a> or <a class="link" href="GstControlSource.html#gst-control-source-get-value-array" title="gst_control_source_get_value_array ()"><code class="function">gst_control_source_get_value_array()</code></a>.
 </p>
 <p>
 For implementing a new <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> one has to implement a
 <span class="type">GstControlSourceBind</span> method, which will depending on the <a href="http://library.gnome.org/devel/gobject/unstable/gobject-GParamSpec.html#GParamSpec"><span class="type">GParamSpec</span></a> set up
 the control source for use and sets the <a class="link" href="GstControlSource.html#GstControlSourceGetValue" title="GstControlSourceGetValue ()"><span class="type">GstControlSourceGetValue</span></a> and
 <a class="link" href="GstControlSource.html#GstControlSourceGetValueArray" title="GstControlSourceGetValueArray ()"><span class="type">GstControlSourceGetValueArray</span></a> functions. These are then used by
 <a class="link" href="GstControlSource.html#gst-control-source-get-value" title="gst_control_source_get_value ()"><code class="function">gst_control_source_get_value()</code></a> or <a class="link" href="GstControlSource.html#gst-control-source-get-value-array" title="gst_control_source_get_value_array ()"><code class="function">gst_control_source_get_value_array()</code></a>
 to get values for specific timestamps.
 </p>
 </div>
 <div class="refsect1">
 <a name="GstControlSource.details"></a><h2>Details</h2>
 <div class="refsect2">
 <a name="GstValueArray"></a><h3>GstValueArray</h3>
 <pre class="programlisting">typedef struct _GstValueArray GstValueArray;</pre>
 </div>
 <hr>
 <div class="refsect2">
 <a name="GstControlSource-struct"></a><h3>struct GstControlSource</h3>
 <pre class="programlisting">struct GstControlSource {
   GstControlSourceGetValue get_value;             /* Returns the value for a property at a given timestamp */
   GstControlSourceGetValueArray get_value_array;  /* Returns values for a property in a given timespan */
 };
 </pre>
 <p>
 The instance structure of <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a>.
 </p>
 <div class="variablelist"><table border="0">
 <col align="left" valign="top">
 <tbody>
 <tr>
 <td><p><span class="term"><a class="link" href="GstControlSource.html#GstControlSourceGetValue" title="GstControlSourceGetValue ()"><span class="type">GstControlSourceGetValue</span></a> <em class="structfield"><code><a name="GstControlSource-struct.get-value"></a>get_value</code></em>;</span></p></td>
 <td>Function for returning a value for a given timestamp</td>
 </tr>
 <tr>
 <td><p><span class="term"><a class="link" href="GstControlSource.html#GstControlSourceGetValueArray" title="GstControlSourceGetValueArray ()"><span class="type">GstControlSourceGetValueArray</span></a> <em class="structfield"><code><a name="GstControlSource-struct.get-value-array"></a>get_value_array</code></em>;</span></p></td>
 <td>Function for returning a <a class="link" href="GstControlSource.html#GstValueArray" title="GstValueArray"><span class="type">GstValueArray</span></a> for a given timestamp</td>
 </tr>
 </tbody>
 </table></div>
 </div>
 <hr>
 <div class="refsect2">
 <a name="GstControlSourceClass"></a><h3>struct GstControlSourceClass</h3>
 <pre class="programlisting">struct GstControlSourceClass {
   GstObjectClass parent_class;
 };
 </pre>
 <p>
 The class structure of <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a>.
 </p>
 <div class="variablelist"><table border="0">
 <col align="left" valign="top">
 <tbody><tr>
 <td><p><span class="term"><a class="link" href="GstObject.html#GstObjectClass" title="struct GstObjectClass"><span class="type">GstObjectClass</span></a> <em class="structfield"><code><a name="GstControlSourceClass.parent-class"></a>parent_class</code></em>;</span></p></td>
 <td>Parent class</td>
 </tr></tbody>
 </table></div>
 </div>
 <hr>
 <div class="refsect2">
 <a name="GstControlSourceGetValue"></a><h3>GstControlSourceGetValue ()</h3>
 <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>            (*GstControlSourceGetValue)         (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *value</code></em>);</pre>
 <p>
 Function for returning a value for a given timestamp.
 </p>
 <div class="variablelist"><table border="0">
 <col align="left" valign="top">
 <tbody>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>self</code></em> :</span></p></td>
 <td>the <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> instance</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>timestamp</code></em> :</span></p></td>
 <td>timestamp for which a value should be calculated</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>value</code></em> :</span></p></td>
 <td>a <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Generic-values.html#GValue"><span class="type">GValue</span></a> which will be set to the result. It must be initialized to the correct type.</td>
 </tr>
 <tr>
 <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
 <td>
 <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the value was successfully calculated.</td>
 </tr>
 </tbody>
 </table></div>
 </div>
 <hr>
 <div class="refsect2">
 <a name="GstControlSourceGetValueArray"></a><h3>GstControlSourceGetValueArray ()</h3>
 <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>            (*GstControlSourceGetValueArray)    (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> interval</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> n_values</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *values</code></em>);</pre>
 <p>
 Function for returning an array of values for starting at a given timestamp.
 </p>
 <div class="variablelist"><table border="0">
 <col align="left" valign="top">
 <tbody>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>self</code></em> :</span></p></td>
 <td>the <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> instance</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>timestamp</code></em> :</span></p></td>
 <td>timestamp for which a value should be calculated</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>interval</code></em> :</span></p></td>
 <td>the time spacing between subsequent values</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>n_values</code></em> :</span></p></td>
 <td>the number of values</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>values</code></em> :</span></p></td>
 <td>array to put control-values in</td>
 </tr>
 <tr>
 <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
 <td>
 <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the values were successfully calculated.</td>
 </tr>
 </tbody>
 </table></div>
 </div>
 <hr>
 <div class="refsect2">
 <a name="GstTimedValue"></a><h3>struct GstTimedValue</h3>
 <pre class="programlisting">struct GstTimedValue {
   GstClockTime timestamp;
   gdouble      value;
 };
 </pre>
 <p>
 Structure for saving a timestamp and a value.
 </p>
 <div class="variablelist"><table border="0">
 <col align="left" valign="top">
 <tbody>
 <tr>
 <td><p><span class="term"><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> <em class="structfield"><code><a name="GstTimedValue.timestamp"></a>timestamp</code></em>;</span></p></td>
 <td>timestamp of the value change</td>
 </tr>
 <tr>
 <td><p><span class="term"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> <em class="structfield"><code><a name="GstTimedValue.value"></a>value</code></em>;</span></p></td>
 <td>the corresponding value</td>
 </tr>
 </tbody>
 </table></div>
 </div>
 <hr>
 <div class="refsect2">
 <a name="gst-control-source-get-value"></a><h3>gst_control_source_get_value ()</h3>
 <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>            gst_control_source_get_value        (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *value</code></em>);</pre>
 <p>
 Gets the value for this <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> at a given timestamp.
 </p>
 <div class="variablelist"><table border="0">
 <col align="left" valign="top">
 <tbody>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>self</code></em> :</span></p></td>
 <td>the <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> object</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>timestamp</code></em> :</span></p></td>
 <td>the time for which the value should be returned</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>value</code></em> :</span></p></td>
 <td>the value</td>
 </tr>
 <tr>
 <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
 <td>FALSE if the value couldn't be returned, TRUE otherwise.</td>
 </tr>
 </tbody>
 </table></div>
 </div>
 <hr>
 <div class="refsect2">
 <a name="gst-control-source-get-value-array"></a><h3>gst_control_source_get_value_array ()</h3>
 <pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>            gst_control_source_get_value_array  (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                                          <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> interval</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> n_values</code></em>,
                                                          <em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *values</code></em>);</pre>
 <p>
 Gets an array of values for for this <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a>. Values that are
 undefined contain NANs.
 </p>
 <div class="variablelist"><table border="0">
 <col align="left" valign="top">
 <tbody>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>self</code></em> :</span></p></td>
 <td>the <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> object</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>timestamp</code></em> :</span></p></td>
 <td>the first timestamp</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>interval</code></em> :</span></p></td>
 <td>the time steps</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>n_values</code></em> :</span></p></td>
 <td>the number of values to fetch</td>
 </tr>
 <tr>
 <td><p><span class="term"><em class="parameter"><code>values</code></em> :</span></p></td>
 <td>array to put control-values in</td>
 </tr>
 <tr>
 <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
 <td>
 <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the given array could be filled, <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> otherwise</td>
 </tr>
 </tbody>
 </table></div>
 </div>
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