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<a href="#GstBaseSrc.description" class="shortcut">Description</a>
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<h2><span class="refentrytitle"><a name="GstBaseSrc.top_of_page"></a>GstBaseSrc</span></h2>
<p>GstBaseSrc — Base class for getrange based source elements</p>
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<div class="refsynopsisdiv">
<a name="GstBaseSrc.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis">
#include <gst/base/gstbasesrc.h>
struct <a class="link" href="GstBaseSrc.html#GstBaseSrc-struct" title="struct GstBaseSrc">GstBaseSrc</a>;
struct <a class="link" href="GstBaseSrc.html#GstBaseSrcClass" title="struct GstBaseSrcClass">GstBaseSrcClass</a>;
enum <a class="link" href="GstBaseSrc.html#GstBaseSrcFlags" title="enum GstBaseSrcFlags">GstBaseSrcFlags</a>;
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html#GstFlowReturn"><span class="returnvalue">GstFlowReturn</span></a> <a class="link" href="GstBaseSrc.html#gst-base-src-wait-playing" title="gst_base_src_wait_playing ()">gst_base_src_wait_playing</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</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="GstBaseSrc.html#gst-base-src-is-live" title="gst_base_src_is_live ()">gst_base_src_is_live</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GstBaseSrc.html#gst-base-src-set-live" title="gst_base_src_set_live ()">gst_base_src_set_live</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> live</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GstBaseSrc.html#gst-base-src-set-format" title="gst_base_src_set_format ()">gst_base_src_set_format</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstFormat.html#GstFormat"><span class="type">GstFormat</span></a> format</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="GstBaseSrc.html#gst-base-src-query-latency" title="gst_base_src_query_latency ()">gst_base_src_query_latency</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> *live</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> *min_latency</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> *max_latency</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="returnvalue">guint</span></a> <a class="link" href="GstBaseSrc.html#gst-base-src-get-blocksize" title="gst_base_src_get_blocksize ()">gst_base_src_get_blocksize</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GstBaseSrc.html#gst-base-src-set-blocksize" title="gst_base_src_set_blocksize ()">gst_base_src_set_blocksize</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</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> blocksize</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="GstBaseSrc.html#gst-base-src-get-do-timestamp" title="gst_base_src_get_do_timestamp ()">gst_base_src_get_do_timestamp</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GstBaseSrc.html#gst-base-src-set-do-timestamp" title="gst_base_src_set_do_timestamp ()">gst_base_src_set_do_timestamp</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> timestamp</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GstBaseSrc.html#gst-base-src-set-dynamic-size" title="gst_base_src_set_dynamic_size ()">gst_base_src_set_dynamic_size</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> dynamic</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="GstBaseSrc.html#gst-base-src-new-seamless-segment" title="gst_base_src_new_seamless_segment ()">gst_base_src_new_seamless_segment</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><span class="type">gint64</span> start</code></em>,
<em class="parameter"><code><span class="type">gint64</span> stop</code></em>,
<em class="parameter"><code><span class="type">gint64</span> time</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="GstBaseSrc.html#gst-base-src-set-caps" title="gst_base_src_set_caps ()">gst_base_src_set_caps</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstCaps.html#GstCaps"><span class="type">GstCaps</span></a> *caps</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GstBaseSrc.html#gst-base-src-get-allocator" title="gst_base_src_get_allocator ()">gst_base_src_get_allocator</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstAllocator.html"><span class="type">GstAllocator</span></a> **allocator</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstAllocator.html#GstAllocationParams"><span class="type">GstAllocationParams</span></a> *params</code></em>);
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBufferPool.html#GstBufferPool"><span class="returnvalue">GstBufferPool</span></a> * <a class="link" href="GstBaseSrc.html#gst-base-src-get-buffer-pool" title="gst_base_src_get_buffer_pool ()">gst_base_src_get_buffer_pool</a> (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);
#define <a class="link" href="GstBaseSrc.html#GST-BASE-SRC-PAD:CAPS" title="GST_BASE_SRC_PAD()">GST_BASE_SRC_PAD</a> (obj)
</pre>
</div>
<div class="refsect1">
<a name="GstBaseSrc.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>
+----GstBaseSrc
+----<a class="link" href="GstPushSrc.html" title="GstPushSrc">GstPushSrc</a>
</pre>
</div>
<div class="refsect1">
<a name="GstBaseSrc.properties"></a><h2>Properties</h2>
<pre class="synopsis">
"<a class="link" href="GstBaseSrc.html#GstBaseSrc--blocksize" title='The "blocksize" property'>blocksize</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="GstBaseSrc.html#GstBaseSrc--do-timestamp" title='The "do-timestamp" property'>do-timestamp</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write
"<a class="link" href="GstBaseSrc.html#GstBaseSrc--num-buffers" title='The "num-buffers" property'>num-buffers</a>" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a> : Read / Write
"<a class="link" href="GstBaseSrc.html#GstBaseSrc--typefind" title='The "typefind" property'>typefind</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="GstBaseSrc.description"></a><h2>Description</h2>
<p>
This is a generice base class for source elements. The following
types of sources are supported:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>random access sources like files</p></li>
<li class="listitem"><p>seekable sources</p></li>
<li class="listitem"><p>live sources</p></li>
</ul></div>
<p>
</p>
<p>
The source can be configured to operate in any <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstFormat.html#GstFormat"><span class="type">GstFormat</span></a> with the
<a class="link" href="GstBaseSrc.html#gst-base-src-set-format" title="gst_base_src_set_format ()"><code class="function">gst_base_src_set_format()</code></a> method. The currently set format determines
the format of the internal <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstSegment.html#GstSegment"><span class="type">GstSegment</span></a> and any <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstEvent.html#GST-EVENT-SEGMENT:CAPS"><span class="type">GST_EVENT_SEGMENT</span></a>
events. The default format for <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> is <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstFormat.html#GST-FORMAT-BYTES:CAPS"><span class="type">GST_FORMAT_BYTES</span></a>.
</p>
<p>
<a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> always supports push mode scheduling. If the following
conditions are met, it also supports pull mode scheduling:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>The format is set to <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstFormat.html#GST-FORMAT-BYTES:CAPS"><span class="type">GST_FORMAT_BYTES</span></a> (default).</p></li>
<li class="listitem"><p><a class="link" href="GstBaseSrc.html#GstBaseSrcClass.is-seekable"><code class="function">GstBaseSrcClass.is_seekable()</code></a> returns <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.</p></li>
</ul></div>
<p>
</p>
<p>
If all the conditions are met for operating in pull mode, <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> is
automatically seekable in push mode as well. The following conditions must
be met to make the element seekable in push mode when the format is not
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstFormat.html#GST-FORMAT-BYTES:CAPS"><span class="type">GST_FORMAT_BYTES</span></a>:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>
<a class="link" href="GstBaseSrc.html#GstBaseSrcClass.is-seekable"><code class="function">GstBaseSrcClass.is_seekable()</code></a> returns <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.
</p></li>
<li class="listitem"><p>
<a class="link" href="GstBaseSrc.html#GstBaseSrcClass.query"><code class="function">GstBaseSrcClass.query()</code></a> can convert all supported seek formats to the
internal format as set with <a class="link" href="GstBaseSrc.html#gst-base-src-set-format" title="gst_base_src_set_format ()"><code class="function">gst_base_src_set_format()</code></a>.
</p></li>
<li class="listitem"><p>
<a class="link" href="GstBaseSrc.html#GstBaseSrcClass.do-seek"><code class="function">GstBaseSrcClass.do_seek()</code></a> is implemented, performs the seek and returns
<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.
</p></li>
</ul></div>
<p>
</p>
<p>
When the element does not meet the requirements to operate in pull mode, the
offset and length in the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> method should be ignored.
It is recommended to subclass <a class="link" href="GstPushSrc.html" title="GstPushSrc"><span class="type">GstPushSrc</span></a> instead, in this situation. If the
element can operate in pull mode but only with specific offsets and
lengths, it is allowed to generate an error when the wrong values are passed
to the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> function.
</p>
<p>
<a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> has support for live sources. Live sources are sources that when
paused discard data, such as audio or video capture devices. A typical live
source also produces data at a fixed rate and thus provides a clock to publish
this rate.
Use <a class="link" href="GstBaseSrc.html#gst-base-src-set-live" title="gst_base_src_set_live ()"><code class="function">gst_base_src_set_live()</code></a> to activate the live source mode.
</p>
<p>
A live source does not produce data in the PAUSED state. This means that the
<a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> method will not be called in PAUSED but only in
PLAYING. To signal the pipeline that the element will not produce data, the
return value from the READY to PAUSED state will be
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#GST-STATE-CHANGE-NO-PREROLL:CAPS"><span class="type">GST_STATE_CHANGE_NO_PREROLL</span></a>.
</p>
<p>
A typical live source will timestamp the buffers it creates with the
current running time of the pipeline. This is one reason why a live source
can only produce data in the PLAYING state, when the clock is actually
distributed and running.
</p>
<p>
Live sources that synchronize and block on the clock (an audio source, for
example) can use <a class="link" href="GstBaseSrc.html#gst-base-src-wait-playing" title="gst_base_src_wait_playing ()"><code class="function">gst_base_src_wait_playing()</code></a> when the
<a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> function was interrupted by a state change to
PAUSED.
</p>
<p>
The <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.get-times"><code class="function">GstBaseSrcClass.get_times()</code></a> method can be used to implement pseudo-live
sources. It only makes sense to implement the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.get-times"><code class="function">GstBaseSrcClass.get_times()</code></a>
function if the source is a live source. The <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.get-times"><code class="function">GstBaseSrcClass.get_times()</code></a>
function should return timestamps starting from 0, as if it were a non-live
source. The base class will make sure that the timestamps are transformed
into the current running_time. The base source will then wait for the
calculated running_time before pushing out the buffer.
</p>
<p>
For live sources, the base class will by default report a latency of 0.
For pseudo live sources, the base class will by default measure the difference
between the first buffer timestamp and the start time of get_times and will
report this value as the latency.
Subclasses should override the query function when this behaviour is not
acceptable.
</p>
<p>
There is only support in <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> for exactly one source pad, which
should be named "src". A source implementation (subclass of <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a>)
should install a pad template in its class_init function, like so:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13
14
15</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="gtkdoc kwb">static void</span>
<span class="function">my_element_class_init</span> <span class="gtkdoc opt">(</span>GstMyElementClass <span class="gtkdoc opt">*</span>klass<span class="gtkdoc opt">)</span>
<span class="gtkdoc opt">{</span>
GstElementClass <span class="gtkdoc opt">*</span>gstelement_class <span class="gtkdoc opt">=</span> <span class="function">GST_ELEMENT_CLASS</span> <span class="gtkdoc opt">(</span>klass<span class="gtkdoc opt">);</span>
<span class="gtkdoc slc">// srctemplate should be a <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPadTemplate.html#GstStaticPadTemplate">GstStaticPadTemplate</a> with direction</span>
<span class="gtkdoc slc">// <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html#GST-PAD-SRC:CAPS">GST_PAD_SRC</a> and name "src"</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-class-add-pad-template">gst_element_class_add_pad_template</a></span> <span class="gtkdoc opt">(</span>gstelement_class<span class="gtkdoc opt">,</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPadTemplate.html#gst-static-pad-template-get">gst_static_pad_template_get</a></span> <span class="gtkdoc opt">(&</span>srctemplate<span class="gtkdoc opt">));</span>
<span class="function"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-class-set-static-metadata">gst_element_class_set_static_metadata</a></span> <span class="gtkdoc opt">(</span>gstelement_class<span class="gtkdoc opt">,</span>
<span class="string">"Source name"</span><span class="gtkdoc opt">,</span>
<span class="string">"Source"</span><span class="gtkdoc opt">,</span>
<span class="string">"My Source element"</span><span class="gtkdoc opt">,</span>
<span class="string">"The author <my.sink@my.email>"</span><span class="gtkdoc opt">);</span>
<span class="gtkdoc opt">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
</p>
<p>
</p>
<div class="refsect2">
<a name="idp57348208"></a><h3>Controlled shutdown of live sources in applications</h3>
<p>
Applications that record from a live source may want to stop recording
in a controlled way, so that the recording is stopped, but the data
already in the pipeline is processed to the end (remember that many live
sources would go on recording forever otherwise). For that to happen the
application needs to make the source stop recording and send an EOS
event down the pipeline. The application would then wait for an
EOS message posted on the pipeline's bus to know when all data has
been processed and the pipeline can safely be stopped.
</p>
<p>
An application may send an EOS event to a source element to make it
perform the EOS logic (send EOS event downstream or post a
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstMessage.html#GST-MESSAGE-SEGMENT-DONE:CAPS"><span class="type">GST_MESSAGE_SEGMENT_DONE</span></a> on the bus). This can typically be done
with the <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#gst-element-send-event"><code class="function">gst_element_send_event()</code></a> function on the element or its parent bin.
</p>
<p>
After the EOS has been sent to the element, the application should wait for
an EOS message to be posted on the pipeline's bus. Once this EOS message is
received, it may safely shut down the entire pipeline.
</p>
<p>
Last reviewed on 2007-12-19 (0.10.16)
</p>
</div>
<p>
</p>
</div>
<div class="refsect1">
<a name="GstBaseSrc.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="GstBaseSrc-struct"></a><h3>struct GstBaseSrc</h3>
<pre class="programlisting">struct GstBaseSrc;</pre>
<p>
The opaque <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> data structure.
</p>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrcClass"></a><h3>struct GstBaseSrcClass</h3>
<pre class="programlisting">struct GstBaseSrcClass {
GstElementClass parent_class;
/* virtual methods for subclasses */
/* get caps from subclass */
GstCaps* (*get_caps) (GstBaseSrc *src, GstCaps *filter);
/* decide on caps */
gboolean (*negotiate) (GstBaseSrc *src);
/* called if, in negotiation, caps need fixating */
GstCaps * (*fixate) (GstBaseSrc *src, GstCaps *caps);
/* notify the subclass of new caps */
gboolean (*set_caps) (GstBaseSrc *src, GstCaps *caps);
/* setup allocation query */
gboolean (*decide_allocation) (GstBaseSrc *src, GstQuery *query);
/* start and stop processing, ideal for opening/closing the resource */
gboolean (*start) (GstBaseSrc *src);
gboolean (*stop) (GstBaseSrc *src);
/* given a buffer, return start and stop time when it should be pushed
* out. The base class will sync on the clock using these times. */
void (*get_times) (GstBaseSrc *src, GstBuffer *buffer,
GstClockTime *start, GstClockTime *end);
/* get the total size of the resource in bytes */
gboolean (*get_size) (GstBaseSrc *src, guint64 *size);
/* check if the resource is seekable */
gboolean (*is_seekable) (GstBaseSrc *src);
/* Prepare the segment on which to perform do_seek(), converting to the
* current basesrc format. */
gboolean (*prepare_seek_segment) (GstBaseSrc *src, GstEvent *seek,
GstSegment *segment);
/* notify subclasses of a seek */
gboolean (*do_seek) (GstBaseSrc *src, GstSegment *segment);
/* unlock any pending access to the resource. subclasses should unlock
* any function ASAP. */
gboolean (*unlock) (GstBaseSrc *src);
/* Clear any pending unlock request, as we succeeded in unlocking */
gboolean (*unlock_stop) (GstBaseSrc *src);
/* notify subclasses of a query */
gboolean (*query) (GstBaseSrc *src, GstQuery *query);
/* notify subclasses of an event */
gboolean (*event) (GstBaseSrc *src, GstEvent *event);
/* ask the subclass to create a buffer with offset and size, the default
* implementation will call alloc and fill. */
GstFlowReturn (*create) (GstBaseSrc *src, guint64 offset, guint size,
GstBuffer **buf);
/* ask the subclass to allocate an output buffer. The default implementation
* will use the negotiated allocator. */
GstFlowReturn (*alloc) (GstBaseSrc *src, guint64 offset, guint size,
GstBuffer **buf);
/* ask the subclass to fill the buffer with data from offset and size */
GstFlowReturn (*fill) (GstBaseSrc *src, guint64 offset, guint size,
GstBuffer *buf);
};
</pre>
<p>
Subclasses can override any of the available virtual methods or not, as
needed. At the minimum, the <em class="parameter"><code>create</code></em> method should be overridden to produce
buffers.
</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 href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#GstElementClass"><span class="type">GstElementClass</span></a> <em class="structfield"><code><a name="GstBaseSrcClass.parent-class"></a>parent_class</code></em>;</span></p></td>
<td>Element parent class</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.get-caps"></a>get_caps</code></em> ()</span></p></td>
<td>Called to get the caps to report</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.negotiate"></a>negotiate</code></em> ()</span></p></td>
<td>Negotiated the caps with the peer.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.fixate"></a>fixate</code></em> ()</span></p></td>
<td>Called during negotiation if caps need fixating. Implement instead of
setting a fixate function on the source pad.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.set-caps"></a>set_caps</code></em> ()</span></p></td>
<td>Notify subclass of changed output caps</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.decide-allocation"></a>decide_allocation</code></em> ()</span></p></td>
<td>configure the allocation query</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.start"></a>start</code></em> ()</span></p></td>
<td>Start processing. Subclasses should open resources and prepare
to produce data. Implementation should call <code class="function">gst_base_src_start_complete()</code>
when the operation completes, either from the current thread or any other
thread that finishes the start operation asynchronously.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.stop"></a>stop</code></em> ()</span></p></td>
<td>Stop processing. Subclasses should use this to close resources.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.get-times"></a>get_times</code></em> ()</span></p></td>
<td>Given a buffer, return the start and stop time when it
should be pushed out. The base class will sync on the clock using
these times.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.get-size"></a>get_size</code></em> ()</span></p></td>
<td>Return the total size of the resource, in the configured format.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.is-seekable"></a>is_seekable</code></em> ()</span></p></td>
<td>Check if the source can seek</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.prepare-seek-segment"></a>prepare_seek_segment</code></em> ()</span></p></td>
<td>Prepare the GstSegment that will be passed to the
do_seek vmethod for executing a seek request. Sub-classes should override
this if they support seeking in formats other than the configured native
format. By default, it tries to convert the seek arguments to the
configured native format and prepare a segment in that format.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.do-seek"></a>do_seek</code></em> ()</span></p></td>
<td>Perform seeking on the resource to the indicated segment.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.unlock"></a>unlock</code></em> ()</span></p></td>
<td>Unlock any pending access to the resource. Subclasses should
unblock any blocked function ASAP. In particular, any <code class="function">create()</code> function in
progress should be unblocked and should return GST_FLOW_FLUSHING. Any
future <em class="parameter"><code>create</code></em>() function call should also return GST_FLOW_FLUSHING
until the <em class="parameter"><code>unlock_stop</code></em>() function has been called.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.unlock-stop"></a>unlock_stop</code></em> ()</span></p></td>
<td>Clear the previous unlock request. Subclasses should clear
any state they set during <code class="function">unlock()</code>, such as clearing command queues.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.query"></a>query</code></em> ()</span></p></td>
<td>Handle a requested query.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.event"></a>event</code></em> ()</span></p></td>
<td>Override this to implement custom event handling.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.create"></a>create</code></em> ()</span></p></td>
<td>Ask the subclass to create a buffer with offset and size.
When the subclass returns GST_FLOW_OK, it MUST return a buffer of the
requested size unless fewer bytes are available because an EOS condition
is near. No buffer should be returned when the return value is different
from GST_FLOW_OK. A return value of GST_FLOW_EOS signifies that the
end of stream is reached. The default implementation will call <em class="parameter"><code>alloc</code></em> and
then call <em class="parameter"><code>fill</code></em>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.alloc"></a>alloc</code></em> ()</span></p></td>
<td>Ask the subclass to allocate a buffer with for offset and size. The
default implementation will create a new buffer from the negotiated allocator.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstBaseSrcClass.fill"></a>fill</code></em> ()</span></p></td>
<td>Ask the subclass to fill the buffer with data for offset and size. The
passed buffer is guaranteed to hold the requested amount of bytes.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrcFlags"></a><h3>enum GstBaseSrcFlags</h3>
<pre class="programlisting">typedef enum {
GST_BASE_SRC_FLAG_STARTING = (GST_ELEMENT_FLAG_LAST << 0),
GST_BASE_SRC_FLAG_STARTED = (GST_ELEMENT_FLAG_LAST << 1),
/* padding */
GST_BASE_SRC_FLAG_LAST = (GST_ELEMENT_FLAG_LAST << 6)
} GstBaseSrcFlags;
</pre>
<p>
The <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html"><span class="type">GstElement</span></a> flags that a basesrc element may have.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><a name="GST-BASE-SRC-FLAG-STARTING:CAPS"></a><span class="term"><code class="literal">GST_BASE_SRC_FLAG_STARTING</code></span></p></td>
<td>has source is starting
</td>
</tr>
<tr>
<td><p><a name="GST-BASE-SRC-FLAG-STARTED:CAPS"></a><span class="term"><code class="literal">GST_BASE_SRC_FLAG_STARTED</code></span></p></td>
<td>has source been started
</td>
</tr>
<tr>
<td><p><a name="GST-BASE-SRC-FLAG-LAST:CAPS"></a><span class="term"><code class="literal">GST_BASE_SRC_FLAG_LAST</code></span></p></td>
<td>offset to define more flags
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-wait-playing"></a><h3>gst_base_src_wait_playing ()</h3>
<pre class="programlisting"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html#GstFlowReturn"><span class="returnvalue">GstFlowReturn</span></a> gst_base_src_wait_playing (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<p>
If the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.create"><code class="function">GstBaseSrcClass.create()</code></a> method performs its own synchronisation
against the clock it must unblock when going from PLAYING to the PAUSED state
and call this method before continuing to produce the remaining data.
</p>
<p>
This function will block until a state change to PLAYING happens (in which
case this function returns <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html#GST-FLOW-OK:CAPS"><span class="type">GST_FLOW_OK</span></a>) or the processing must be stopped due
to a state change to READY or a FLUSH event (in which case this function
returns <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html#GST-FLOW-FLUSHING:CAPS"><span class="type">GST_FLOW_FLUSHING</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"><em class="parameter"><code>src</code></em> :</span></p></td>
<td>the src</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html#GST-FLOW-OK:CAPS"><span class="type">GST_FLOW_OK</span></a> if <em class="parameter"><code>src</code></em> is PLAYING and processing can
continue. Any other return value should be returned from the create vmethod.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-is-live"></a><h3>gst_base_src_is_live ()</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_base_src_is_live (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<p>
Check if an element is in live mode.
</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>src</code></em> :</span></p></td>
<td>base source instance</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 element is in live mode.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-live"></a><h3>gst_base_src_set_live ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_base_src_set_live (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> live</code></em>);</pre>
<p>
If the element listens to a live source, <em class="parameter"><code>live</code></em> should
be set to <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a>.
</p>
<p>
A live source will not produce data in the PAUSED state and
will therefore not be able to participate in the PREROLL phase
of a pipeline. To signal this fact to the application and the
pipeline, the state change return value of the live source will
be GST_STATE_CHANGE_NO_PREROLL.
</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>src</code></em> :</span></p></td>
<td>base source instance</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>live</code></em> :</span></p></td>
<td>new live-mode</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-format"></a><h3>gst_base_src_set_format ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_base_src_set_format (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstFormat.html#GstFormat"><span class="type">GstFormat</span></a> format</code></em>);</pre>
<p>
Sets the default format of the source. This will be the format used
for sending SEGMENT events and for performing seeks.
</p>
<p>
If a format of GST_FORMAT_BYTES is set, the element will be able to
operate in pull mode if the <a class="link" href="GstBaseSrc.html#GstBaseSrcClass.is-seekable"><code class="function">GstBaseSrcClass.is_seekable()</code></a> returns TRUE.
</p>
<p>
This function must only be called in states < <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstElement.html#GST-STATE-PAUSED:CAPS"><code class="literal">GST_STATE_PAUSED</code></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"><em class="parameter"><code>src</code></em> :</span></p></td>
<td>base source instance</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>format</code></em> :</span></p></td>
<td>the format to use</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-query-latency"></a><h3>gst_base_src_query_latency ()</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_base_src_query_latency (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> *live</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> *min_latency</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstClock.html#GstClockTime"><span class="type">GstClockTime</span></a> *max_latency</code></em>);</pre>
<p>
Query the source for the latency parameters. <em class="parameter"><code>live</code></em> will be TRUE when <em class="parameter"><code>src</code></em> is
configured as a live source. <em class="parameter"><code>min_latency</code></em> will be set to the difference
between the running time and the timestamp of the first buffer.
<em class="parameter"><code>max_latency</code></em> is always the undefined value of -1.
</p>
<p>
This function is mostly used by subclasses.
</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>src</code></em> :</span></p></td>
<td>the source</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>live</code></em> :</span></p></td>
<td>if the source is live. <span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is ok, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>min_latency</code></em> :</span></p></td>
<td>the min latency of the source. <span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is ok, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>max_latency</code></em> :</span></p></td>
<td>the max latency of the source. <span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is ok, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>TRUE if the query succeeded.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-get-blocksize"></a><h3>gst_base_src_get_blocksize ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="returnvalue">guint</span></a> gst_base_src_get_blocksize (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<p>
Get the number of bytes that <em class="parameter"><code>src</code></em> will push out with each buffer.
</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>src</code></em> :</span></p></td>
<td>the source</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>the number of bytes pushed with each buffer.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-blocksize"></a><h3>gst_base_src_set_blocksize ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_base_src_set_blocksize (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</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> blocksize</code></em>);</pre>
<p>
Set the number of bytes that <em class="parameter"><code>src</code></em> will push out with each buffer. When
<em class="parameter"><code>blocksize</code></em> is set to -1, a default length will be used.
</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>src</code></em> :</span></p></td>
<td>the source</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>blocksize</code></em> :</span></p></td>
<td>the new blocksize in bytes</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-get-do-timestamp"></a><h3>gst_base_src_get_do_timestamp ()</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_base_src_get_do_timestamp (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<p>
Query if <em class="parameter"><code>src</code></em> timestamps outgoing buffers based on the current running_time.
</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>src</code></em> :</span></p></td>
<td>the source</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 base class will automatically timestamp outgoing buffers.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-do-timestamp"></a><h3>gst_base_src_set_do_timestamp ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_base_src_set_do_timestamp (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> timestamp</code></em>);</pre>
<p>
Configure <em class="parameter"><code>src</code></em> to automatically timestamp outgoing buffers based on the
current running_time of the pipeline. This property is mostly useful for live
sources.
</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>src</code></em> :</span></p></td>
<td>the source</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>timestamp</code></em> :</span></p></td>
<td>enable or disable timestamping</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-dynamic-size"></a><h3>gst_base_src_set_dynamic_size ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_base_src_set_dynamic_size (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> dynamic</code></em>);</pre>
<p>
If not <em class="parameter"><code>dynamic</code></em>, size is only updated when needed, such as when trying to
read past current tracked size. Otherwise, size is checked for upon each
read.
</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>src</code></em> :</span></p></td>
<td>base source instance</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>dynamic</code></em> :</span></p></td>
<td>new dynamic size mode</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-new-seamless-segment"></a><h3>gst_base_src_new_seamless_segment ()</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_base_src_new_seamless_segment (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><span class="type">gint64</span> start</code></em>,
<em class="parameter"><code><span class="type">gint64</span> stop</code></em>,
<em class="parameter"><code><span class="type">gint64</span> time</code></em>);</pre>
<p>
Prepare a new seamless segment for emission downstream. This function must
only be called by derived sub-classes, and only from the <code class="function">create()</code> function,
as the stream-lock needs to be held.
</p>
<p>
The format for the new segment will be the current format of the source, as
configured with <a class="link" href="GstBaseSrc.html#gst-base-src-set-format" title="gst_base_src_set_format ()"><code class="function">gst_base_src_set_format()</code></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"><em class="parameter"><code>src</code></em> :</span></p></td>
<td>The source</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>start</code></em> :</span></p></td>
<td>The new start value for the segment</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>stop</code></em> :</span></p></td>
<td>Stop value for the new segment</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>time</code></em> :</span></p></td>
<td>The new time value for the start of the new segent</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 preparation of the seamless segment succeeded.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-set-caps"></a><h3>gst_base_src_set_caps ()</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_base_src_set_caps (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstCaps.html#GstCaps"><span class="type">GstCaps</span></a> *caps</code></em>);</pre>
<p>
Set new caps on the basesrc source pad.
</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>src</code></em> :</span></p></td>
<td>a <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>caps</code></em> :</span></p></td>
<td>a <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstCaps.html#GstCaps"><span class="type">GstCaps</span></a>
</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 caps could be set</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-get-allocator"></a><h3>gst_base_src_get_allocator ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_base_src_get_allocator (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstAllocator.html"><span class="type">GstAllocator</span></a> **allocator</code></em>,
<em class="parameter"><code><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstAllocator.html#GstAllocationParams"><span class="type">GstAllocationParams</span></a> *params</code></em>);</pre>
<p>
Lets <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> sub-classes to know the memory <em class="parameter"><code>allocator</code></em>
used by the base class and its <em class="parameter"><code>params</code></em>.
</p>
<p>
Unref the <em class="parameter"><code>allocator</code></em> after use it.
</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>src</code></em> :</span></p></td>
<td>a <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>allocator</code></em> :</span></p></td>
<td>the <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstAllocator.html"><span class="type">GstAllocator</span></a>
used. <span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is ok, both for passing and for returning."><span class="acronym">allow-none</span></acronym>][<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>params</code></em> :</span></p></td>
<td>the
<span class="type">GstAllocatorParams</span> of <em class="parameter"><code>allocator</code></em>. <span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>][<acronym title="NULL is ok, both for passing and for returning."><span class="acronym">allow-none</span></acronym>][<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-base-src-get-buffer-pool"></a><h3>gst_base_src_get_buffer_pool ()</h3>
<pre class="programlisting"><a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBufferPool.html#GstBufferPool"><span class="returnvalue">GstBufferPool</span></a> * gst_base_src_get_buffer_pool (<em class="parameter"><code><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a> *src</code></em>);</pre>
<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>src</code></em> :</span></p></td>
<td>a <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>the instance of the <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstBufferPool.html#GstBufferPool"><span class="type">GstBufferPool</span></a> used
by the src; free it after use it. <span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GST-BASE-SRC-PAD:CAPS"></a><h3>GST_BASE_SRC_PAD()</h3>
<pre class="programlisting">#define GST_BASE_SRC_PAD(obj) (GST_BASE_SRC_CAST (obj)->srcpad)
</pre>
<p>
Gives the pointer to the <a href="http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html"><span class="type">GstPad</span></a> object of the element.
</p>
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<td><p><span class="term"><em class="parameter"><code>obj</code></em> :</span></p></td>
<td>base source instance</td>
</tr></tbody>
</table></div>
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</div>
<div class="refsect1">
<a name="GstBaseSrc.property-details"></a><h2>Property Details</h2>
<div class="refsect2">
<a name="GstBaseSrc--blocksize"></a><h3>The <code class="literal">"blocksize"</code> property</h3>
<pre class="programlisting"> "blocksize" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#guint"><span class="type">guint</span></a> : Read / Write</pre>
<p>Size in bytes to read per buffer (-1 = default).</p>
<p>Default value: 4096</p>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrc--do-timestamp"></a><h3>The <code class="literal">"do-timestamp"</code> property</h3>
<pre class="programlisting"> "do-timestamp" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write</pre>
<p>Apply current stream time to buffers.</p>
<p>Default value: FALSE</p>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrc--num-buffers"></a><h3>The <code class="literal">"num-buffers"</code> property</h3>
<pre class="programlisting"> "num-buffers" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a> : Read / Write</pre>
<p>Number of buffers to output before sending EOS (-1 = unlimited).</p>
<p>Allowed values: >= G_MAXULONG</p>
<p>Default value: -1</p>
</div>
<hr>
<div class="refsect2">
<a name="GstBaseSrc--typefind"></a><h3>The <code class="literal">"typefind"</code> property</h3>
<pre class="programlisting"> "typefind" <a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> : Read / Write</pre>
<p>Run typefind before negotiating.</p>
<p>Default value: FALSE</p>
</div>
</div>
<div class="refsect1">
<a name="GstBaseSrc.see-also"></a><h2>See Also</h2>
<a class="link" href="GstPushSrc.html" title="GstPushSrc"><span class="type">GstPushSrc</span></a>, <a class="link" href="GstBaseTransform.html" title="GstBaseTransform"><span class="type">GstBaseTransform</span></a>, <a class="link" href="GstBaseSink.html" title="GstBaseSink"><span class="type">GstBaseSink</span></a>
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