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<a href="#gstreamer-plugins-queue.synopsis" class="shortcut">Top</a>
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<a href="#gstreamer-plugins-queue.description" class="shortcut">Description</a>
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<a href="#gstreamer-plugins-queue.object-hierarchy" class="shortcut">Object Hierarchy</a>
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<a href="#gstreamer-plugins-queue.properties" class="shortcut">Properties</a>
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<a href="#gstreamer-plugins-queue.signals" class="shortcut">Signals</a>
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<div class="refentry">
<a name="gstreamer-plugins-queue"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="gstreamer-plugins-queue.top_of_page"></a>queue</span></h2>
<p>queue — Simple data queue</p>
</td>
<td valign="top" align="right"></td>
</tr></table></div>
<div class="refsynopsisdiv">
<a name="gstreamer-plugins-queue.synopsis"></a><h2>Synopsis</h2>
<a name="GstQueue"></a><pre class="synopsis">struct <a class="link" href="gstreamer-plugins-queue.html#GstQueue-struct" title="struct GstQueue">GstQueue</a>;
enum <a class="link" href="gstreamer-plugins-queue.html#GstQueueLeaky" title="enum GstQueueLeaky">GstQueueLeaky</a>;
</pre>
</div>
<div class="refsect1">
<a name="gstreamer-plugins-queue.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 href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstObject.html">GstObject</a>
+----<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html">GstElement</a>
+----GstQueue
</pre>
</div>
<div class="refsect1">
<a name="gstreamer-plugins-queue.properties"></a><h2>Properties</h2>
<pre class="synopsis">
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--current-level-buffers" title='The "current-level-buffers" property'>current-level-buffers</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--current-level-bytes" title='The "current-level-bytes" property'>current-level-bytes</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--current-level-time" title='The "current-level-time" property'>current-level-time</a>" <span class="type">guint64</span> : Read
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--leaky" title='The "leaky" property'>leaky</a>" <a class="link" href="gstreamer-plugins-queue.html#GstQueueLeaky" title="enum GstQueueLeaky"><span class="type">GstQueueLeaky</span></a> : Read / Write
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--max-size-buffers" title='The "max-size-buffers" property'>max-size-buffers</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--max-size-bytes" title='The "max-size-bytes" property'>max-size-bytes</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--max-size-time" title='The "max-size-time" property'>max-size-time</a>" <span class="type">guint64</span> : Read / Write
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--min-threshold-buffers" title='The "min-threshold-buffers" property'>min-threshold-buffers</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--min-threshold-bytes" title='The "min-threshold-bytes" property'>min-threshold-bytes</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--min-threshold-time" title='The "min-threshold-time" property'>min-threshold-time</a>" <span class="type">guint64</span> : Read / Write
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue--silent" title='The "silent" property'>silent</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write
</pre>
</div>
<div class="refsect1">
<a name="gstreamer-plugins-queue.signals"></a><h2>Signals</h2>
<pre class="synopsis">
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue-overrun" title='The "overrun" signal'>overrun</a>" : <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#G-SIGNAL-RUN-FIRST:CAPS"><code class="literal">Run First</code></a>
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue-running" title='The "running" signal'>running</a>" : <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#G-SIGNAL-RUN-FIRST:CAPS"><code class="literal">Run First</code></a>
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue-underrun" title='The "underrun" signal'>underrun</a>" : <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#G-SIGNAL-RUN-FIRST:CAPS"><code class="literal">Run First</code></a>
"<a class="link" href="gstreamer-plugins-queue.html#GstQueue-pushing" title='The "pushing" signal'>pushing</a>" : <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#G-SIGNAL-RUN-FIRST:CAPS"><code class="literal">Run First</code></a>
</pre>
</div>
<div class="refsect1">
<a name="gstreamer-plugins-queue.description"></a><h2>Description</h2>
<p>
Data is queued until one of the limits specified by the
<a class="link" href="gstreamer-plugins-queue.html#GstQueue--max-size-buffers" title='The "max-size-buffers" property'><span class="type">"max-size-buffers"</span></a>, <a class="link" href="gstreamer-plugins-queue.html#GstQueue--max-size-bytes" title='The "max-size-bytes" property'><span class="type">"max-size-bytes"</span></a> and/or
<a class="link" href="gstreamer-plugins-queue.html#GstQueue--max-size-time" title='The "max-size-time" property'><span class="type">"max-size-time"</span></a> properties has been reached. Any attempt to push
more buffers into the queue will block the pushing thread until more space
becomes available.
</p>
<p>
The queue will create a new thread on the source pad to decouple the
processing on sink and source pad.
</p>
<p>
You can query how many buffers are queued by reading the
<a class="link" href="gstreamer-plugins-queue.html#GstQueue--current-level-buffers" title='The "current-level-buffers" property'><span class="type">"current-level-buffers"</span></a> property. You can track changes
by connecting to the notify::current-level-buffers signal (which
like all signals will be emitted from the streaming thread). The same
applies to the <a class="link" href="gstreamer-plugins-queue.html#GstQueue--current-level-time" title='The "current-level-time" property'><span class="type">"current-level-time"</span></a> and
<a class="link" href="gstreamer-plugins-queue.html#GstQueue--current-level-bytes" title='The "current-level-bytes" property'><span class="type">"current-level-bytes"</span></a> properties.
</p>
<p>
The default queue size limits are 200 buffers, 10MB of data, or
one second worth of data, whichever is reached first.
</p>
<p>
As said earlier, the queue blocks by default when one of the specified
maximums (bytes, time, buffers) has been reached. You can set the
<a class="link" href="gstreamer-plugins-queue.html#GstQueue--leaky" title='The "leaky" property'><span class="type">"leaky"</span></a> property to specify that instead of blocking it should
leak (drop) new or old buffers.
</p>
<p>
The <a class="link" href="gstreamer-plugins-queue.html#GstQueue-underrun" title='The "underrun" signal'><span class="type">"underrun"</span></a> signal is emitted when the queue has less data than
the specified minimum thresholds require (by default: when the queue is
empty). The <a class="link" href="gstreamer-plugins-queue.html#GstQueue-overrun" title='The "overrun" signal'><span class="type">"overrun"</span></a> signal is emitted when the queue is filled
up. Both signals are emitted from the context of the streaming thread.
</p>
<div class="refsynopsisdiv">
<h2>Synopsis</h2>
<div class="refsect2">
<a name="idp10681456"></a><h3>Element Information</h3>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">plugin</span></p></td>
<td>
<a class="link" href="gstreamer-plugins-plugin-coreelements.html#plugin-coreelements">coreelements</a>
</td>
</tr>
<tr>
<td><p><span class="term">author</span></p></td>
<td>Erik Walthinsen &lt;omega@cse.ogi.edu&gt;</td>
</tr>
<tr>
<td><p><span class="term">class</span></p></td>
<td>Generic</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="idp10688912"></a><h3>Element Pads</h3>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>ANY</td>
</tr>
</tbody>
</table></div>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>src</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>source</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>ANY</td>
</tr>
</tbody>
</table></div>
</div>
</div>
<p>
</p>
</div>
<div class="refsect1">
<a name="gstreamer-plugins-queue.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="GstQueue-struct"></a><h3>struct GstQueue</h3>
<pre class="programlisting">struct GstQueue;</pre>
<p>
Opaque <a class="link" href="gstreamer-plugins-queue.html#GstQueue"><span class="type">GstQueue</span></a> structure.
</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueueLeaky"></a><h3>enum GstQueueLeaky</h3>
<pre class="programlisting">enum GstQueueLeaky {
GST_QUEUE_NO_LEAK = 0,
GST_QUEUE_LEAK_UPSTREAM = 1,
GST_QUEUE_LEAK_DOWNSTREAM = 2
};
</pre>
<p>
Buffer dropping scheme to avoid the queue to block when full.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><a name="GST-QUEUE-NO-LEAK:CAPS"></a><span class="term"><code class="literal">GST_QUEUE_NO_LEAK</code></span></p></td>
<td>Not Leaky
</td>
</tr>
<tr>
<td><p><a name="GST-QUEUE-LEAK-UPSTREAM:CAPS"></a><span class="term"><code class="literal">GST_QUEUE_LEAK_UPSTREAM</code></span></p></td>
<td>Leaky on upstream (new buffers)
</td>
</tr>
<tr>
<td><p><a name="GST-QUEUE-LEAK-DOWNSTREAM:CAPS"></a><span class="term"><code class="literal">GST_QUEUE_LEAK_DOWNSTREAM</code></span></p></td>
<td>Leaky on downstream (old buffers)
</td>
</tr>
</tbody>
</table></div>
</div>
</div>
<div class="refsect1">
<a name="gstreamer-plugins-queue.property-details"></a><h2>Property Details</h2>
<div class="refsect2">
<a name="GstQueue--current-level-buffers"></a><h3>The <code class="literal">"current-level-buffers"</code> property</h3>
<pre class="programlisting"> "current-level-buffers" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read</pre>
<p>Current number of buffers in the queue.</p>
<p>Default value: 0</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--current-level-bytes"></a><h3>The <code class="literal">"current-level-bytes"</code> property</h3>
<pre class="programlisting"> "current-level-bytes" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read</pre>
<p>Current amount of data in the queue (bytes).</p>
<p>Default value: 0</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--current-level-time"></a><h3>The <code class="literal">"current-level-time"</code> property</h3>
<pre class="programlisting"> "current-level-time" <span class="type">guint64</span> : Read</pre>
<p>Current amount of data in the queue (in ns).</p>
<p>Default value: 0</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--leaky"></a><h3>The <code class="literal">"leaky"</code> property</h3>
<pre class="programlisting"> "leaky" <a class="link" href="gstreamer-plugins-queue.html#GstQueueLeaky" title="enum GstQueueLeaky"><span class="type">GstQueueLeaky</span></a> : Read / Write</pre>
<p>Where the queue leaks, if at all.</p>
<p>Default value: Not Leaky</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--max-size-buffers"></a><h3>The <code class="literal">"max-size-buffers"</code> property</h3>
<pre class="programlisting"> "max-size-buffers" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write</pre>
<p>Max. number of buffers in the queue (0=disable).</p>
<p>Default value: 200</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--max-size-bytes"></a><h3>The <code class="literal">"max-size-bytes"</code> property</h3>
<pre class="programlisting"> "max-size-bytes" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write</pre>
<p>Max. amount of data in the queue (bytes, 0=disable).</p>
<p>Default value: 10485760</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--max-size-time"></a><h3>The <code class="literal">"max-size-time"</code> property</h3>
<pre class="programlisting"> "max-size-time" <span class="type">guint64</span> : Read / Write</pre>
<p>Max. amount of data in the queue (in ns, 0=disable).</p>
<p>Default value: 1000000000</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--min-threshold-buffers"></a><h3>The <code class="literal">"min-threshold-buffers"</code> property</h3>
<pre class="programlisting"> "min-threshold-buffers" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write</pre>
<p>Min. number of buffers in the queue to allow reading (0=disable).</p>
<p>Default value: 0</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--min-threshold-bytes"></a><h3>The <code class="literal">"min-threshold-bytes"</code> property</h3>
<pre class="programlisting"> "min-threshold-bytes" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write</pre>
<p>Min. amount of data in the queue to allow reading (bytes, 0=disable).</p>
<p>Default value: 0</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--min-threshold-time"></a><h3>The <code class="literal">"min-threshold-time"</code> property</h3>
<pre class="programlisting"> "min-threshold-time" <span class="type">guint64</span> : Read / Write</pre>
<p>Min. amount of data in the queue to allow reading (in ns, 0=disable).</p>
<p>Default value: 0</p>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue--silent"></a><h3>The <code class="literal">"silent"</code> property</h3>
<pre class="programlisting"> "silent" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write</pre>
<p>
Don't emit queue signals. Makes queues more lightweight if no signals are
needed.
</p>
<p>Default value: FALSE</p>
</div>
</div>
<div class="refsect1">
<a name="gstreamer-plugins-queue.signal-details"></a><h2>Signal Details</h2>
<div class="refsect2">
<a name="GstQueue-overrun"></a><h3>The <code class="literal">"overrun"</code> signal</h3>
<pre class="programlisting"><span class="returnvalue">void</span> user_function (<a class="link" href="gstreamer-plugins-queue.html#GstQueue"><span class="type">GstQueue</span></a> *queue,
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data) : <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#G-SIGNAL-RUN-FIRST:CAPS"><code class="literal">Run First</code></a></pre>
<p>
Reports that the buffer became full (overrun).
A buffer is full if the total amount of data inside it (num-buffers, time,
size) is higher than the boundary values which can be set through the
GObject properties.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>queue</code></em> :</span></p></td>
<td>the queue instance</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>user_data</code></em> :</span></p></td>
<td>user data set when the signal handler was connected.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue-running"></a><h3>The <code class="literal">"running"</code> signal</h3>
<pre class="programlisting"><span class="returnvalue">void</span> user_function (<a class="link" href="gstreamer-plugins-queue.html#GstQueue"><span class="type">GstQueue</span></a> *queue,
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data) : <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#G-SIGNAL-RUN-FIRST:CAPS"><code class="literal">Run First</code></a></pre>
<p>
Reports that enough (min-threshold) data is in the queue. Use this signal
together with the underrun signal to pause the pipeline on underrun and
wait for the queue to fill-up before resume playback.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>queue</code></em> :</span></p></td>
<td>the queue instance</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>user_data</code></em> :</span></p></td>
<td>user data set when the signal handler was connected.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue-underrun"></a><h3>The <code class="literal">"underrun"</code> signal</h3>
<pre class="programlisting"><span class="returnvalue">void</span> user_function (<a class="link" href="gstreamer-plugins-queue.html#GstQueue"><span class="type">GstQueue</span></a> *queue,
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data) : <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#G-SIGNAL-RUN-FIRST:CAPS"><code class="literal">Run First</code></a></pre>
<p>
Reports that the buffer became empty (underrun).
A buffer is empty if the total amount of data inside it (num-buffers, time,
size) is lower than the boundary values which can be set through the
GObject properties.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>queue</code></em> :</span></p></td>
<td>the queue instance</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>user_data</code></em> :</span></p></td>
<td>user data set when the signal handler was connected.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GstQueue-pushing"></a><h3>The <code class="literal">"pushing"</code> signal</h3>
<pre class="programlisting"><span class="returnvalue">void</span> user_function (<a class="link" href="gstreamer-plugins-queue.html#GstQueue"><span class="type">GstQueue</span></a> *queue,
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data) : <a href="http://library.gnome.org/devel/gobject/unstable/gobject-Signals.html#G-SIGNAL-RUN-FIRST:CAPS"><code class="literal">Run First</code></a></pre>
<p>
Reports when the queue has enough data to start pushing data again on the
source pad.
</p>
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<td><p><span class="term"><em class="parameter"><code>queue</code></em> :</span></p></td>
<td>the queue instance</td>
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<td><p><span class="term"><em class="parameter"><code>user_data</code></em> :</span></p></td>
<td>user data set when the signal handler was connected.</td>
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