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| <a name="GstPushSrc"></a><div class="titlepage"></div> |
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| <h2><span class="refentrytitle"><a name="GstPushSrc.top_of_page"></a>GstPushSrc</span></h2> |
| <p>GstPushSrc — Base class for push based source elements</p> |
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| <div class="refsect1"> |
| <a name="GstPushSrc.other"></a><h2>Types and Values</h2> |
| <div class="informaltable"><table class="informaltable" width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="name"> |
| <col class="description"> |
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| <tbody> |
| <tr> |
| <td class="datatype_keyword">struct</td> |
| <td class="function_name"><a class="link" href="GstPushSrc.html#GstPushSrc-struct" title="struct GstPushSrc">GstPushSrc</a></td> |
| </tr> |
| <tr> |
| <td class="datatype_keyword">struct</td> |
| <td class="function_name"><a class="link" href="GstPushSrc.html#GstPushSrcClass" title="struct GstPushSrcClass">GstPushSrcClass</a></td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstPushSrc.object-hierarchy"></a><h2>Object Hierarchy</h2> |
| <pre class="screen"> <a href="/usr/share/gtk-doc/html/gobjectgobject-The-Base-Object-Type.html#GObject-struct">GObject</a> |
| <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gobjectgobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a> |
| <span class="lineart">╰──</span> <a href="../html/GstObject.html#GstObject-struct">GstObject</a> |
| <span class="lineart">╰──</span> <a href="../html/GstElement.html#GstElement-struct">GstElement</a> |
| <span class="lineart">╰──</span> <a class="link" href="GstBaseSrc.html" title="GstBaseSrc">GstBaseSrc</a> |
| <span class="lineart">╰──</span> GstPushSrc |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="GstPushSrc.includes"></a><h2>Includes</h2> |
| <pre class="synopsis">#include <gst/base/gstpushsrc.h> |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="GstPushSrc.description"></a><h2>Description</h2> |
| <p>This class is mostly useful for elements that cannot do |
| random access, or at least very slowly. The source usually |
| prefers to push out a fixed size buffer.</p> |
| <p>Subclasses usually operate in a format that is different from the |
| default GST_FORMAT_BYTES format of <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a>.</p> |
| <p>Classes extending this base class will usually be scheduled |
| in a push based mode. If the peer accepts to operate without |
| offsets and within the limits of the allowed block size, this |
| class can operate in getrange based mode automatically. To make |
| this possible, the subclass should implement and override the |
| SCHEDULING query.</p> |
| <p>The subclass should extend the methods from the baseclass in |
| addition to the ::create method.</p> |
| <p>Seeking, flushing, scheduling and sync is all handled by this |
| base class.</p> |
| </div> |
| <div class="refsect1"> |
| <a name="GstPushSrc.functions_details"></a><h2>Functions</h2> |
| <p></p> |
| </div> |
| <div class="refsect1"> |
| <a name="GstPushSrc.other_details"></a><h2>Types and Values</h2> |
| <div class="refsect2"> |
| <a name="GstPushSrc-struct"></a><h3>struct GstPushSrc</h3> |
| <pre class="programlisting">struct GstPushSrc;</pre> |
| <p>The opaque <a class="link" href="GstPushSrc.html" title="GstPushSrc"><span class="type">GstPushSrc</span></a> data structure.</p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstPushSrcClass"></a><h3>struct GstPushSrcClass</h3> |
| <pre class="programlisting">struct GstPushSrcClass { |
| GstBaseSrcClass parent_class; |
| |
| /* ask the subclass to create a buffer, the default implementation |
| * uses alloc and fill */ |
| GstFlowReturn (*create) (GstPushSrc *src, GstBuffer **buf); |
| /* allocate memory for a buffer */ |
| GstFlowReturn (*alloc) (GstPushSrc *src, GstBuffer **buf); |
| /* ask the subclass to fill a buffer */ |
| GstFlowReturn (*fill) (GstPushSrc *src, 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>fill</code></em> |
| method should be overridden to produce |
| buffers.</p> |
| <div class="refsect3"> |
| <a name="GstPushSrcClass.members"></a><h4>Members</h4> |
| <div class="informaltable"><table class="informaltable" width="100%" border="0"> |
| <colgroup> |
| <col width="300px" class="struct_members_name"> |
| <col class="struct_members_description"> |
| <col width="200px" class="struct_members_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="struct_member_name"><p><em class="structfield"><code><a name="GstPushSrcClass.create"></a>create</code></em> ()</p></td> |
| <td class="struct_member_description"><p>Ask the subclass to create a buffer. The subclass decides which |
| size this buffer should be. Other then that, refer to |
| <a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a>.create() for more details. If this method is |
| not implemented, <em class="parameter"><code>alloc</code></em> |
| followed by <em class="parameter"><code>fill</code></em> |
| will be called.</p></td> |
| <td class="struct_member_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="struct_member_name"><p><em class="structfield"><code><a name="GstPushSrcClass.alloc"></a>alloc</code></em> ()</p></td> |
| <td class="struct_member_description"><p>Ask the subclass to allocate a buffer. The subclass decides which |
| size this buffer should be. The default implementation will create |
| a new buffer from the negotiated allocator.</p></td> |
| <td class="struct_member_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="struct_member_name"><p><em class="structfield"><code><a name="GstPushSrcClass.fill"></a>fill</code></em> ()</p></td> |
| <td class="struct_member_description"><p>Ask the subclass to fill the buffer with data.</p></td> |
| <td class="struct_member_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstPushSrc.see-also"></a><h2>See Also</h2> |
| <p><a class="link" href="GstBaseSrc.html" title="GstBaseSrc"><span class="type">GstBaseSrc</span></a></p> |
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