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75 lines
2 KiB
XML
75 lines
2 KiB
XML
<chapter id="cha-plugins">
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<title>What are Plugins</title>
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<para>
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A plugin is a shared library that contains at least one of the following items:
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</para>
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<itemizedlist>
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<listitem>
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<para>
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one or more elementfactories
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</para>
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</listitem>
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<listitem>
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<para>
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one or more typedefinitions
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</para>
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</listitem>
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<listitem>
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<para>
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one or more autopluggers
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</para>
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</listitem>
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<listitem>
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<para>
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exported symbols for use in other plugins
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</para>
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</listitem>
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</itemizedlist>
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<para>
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The plugins have one simple method: plugin_init () where all the elementfactories are
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created and the typedefinitions are registered.
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</para>
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<para>
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the plugins are maintained in the plugin system. Optionally, the typedefinitions and
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the elementfactories can be saved into an XML representation so that the plugin system
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does not have to load all available plugins in order to know their definition.
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</para>
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<para>
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The basic plugin structure has the following fields:
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</para>
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<programlisting>
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struct _GstPlugin {
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gchar *name; /* name of the plugin */
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gchar *longname; /* long name of plugin */
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gchar *filename; /* filename it came from */
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GList *types; /* list of types provided */
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gint numtypes;
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GList *elements; /* list of elements provided */
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gint numelements;
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GList *autopluggers; /* list of autopluggers provided */
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gint numautopluggers;
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gboolean loaded; /* if the plugin is in memory */
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};
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</programlisting>
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<para>
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You can query a GList of available plugins with:
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</para>
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<programlisting>
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GList *plugins;
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plugins = gst_plugin_get_list ();
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while (plugins) {
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GstPlugin *plugin = (GstPlugin *)plugins->data;
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g_print ("plugin: %s\n", gst_plugin_get_name (plugin));
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plugins = g_list_next (plugins);
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}
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</programlisting>
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</chapter>
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