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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<a href="#GstControlSource.synopsis" class="shortcut">Top</a>
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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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<div class="refentry">
<a name="GstControlSource"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<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 <gst/gst.h>
<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 <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer-libs/html/GstController.html"><span class="type">GstController</span></a> to get timestamp-value pairs. A control source
essentially is a function over time, returning gloat values between 0.0 and 1.0.
</p>
<p>
A <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> is used by first getting an instance of a specific
control-source, creating a binding for the control-source to the target property
of the element and then adding the binding to the element. The binding will
convert the data types and value range to fit to the bound property.
</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 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> and
<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" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<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" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<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" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<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" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<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" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<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" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<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" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<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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