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<!-- ##### SECTION Title ##### -->
GstPadTemplate
<!-- ##### SECTION Short_Description ##### -->
Describe the media type of a pad.
<!-- ##### SECTION Long_Description ##### -->
<para>
Padtemplates describe the possible media types a pad or an elementfactory can
handle.
</para>
<para>
Pad and PadTemplates have #GstCaps attached to it to describe the media type they
are capable of dealing with. gst_pad_template_get_caps() is used to get the
caps of a padtemplate. It's not possible to modify the caps of a padtemplate after
creation.
</para>
<para>
Padtemplates can be created with gst_pad_template_new() or with the convenient
GST_PAD_TEMPLATE_FACTORY() macro. A padtemplate can be used to create a pad or
to add to an elementfactory.
</para>
<para>
The following code example shows the code to create a pad from a padtemplate.
<programlisting>
GST_PAD_TEMPLATE_FACTORY (my_template_factory,
"sink", /* the name of the pad */
GST_PAD_SINK, /* the direction of the pad */
GST_PAD_ALWAYS, /* when this pad will be present */
GST_CAPS_NEW ( /* the capabilities of the padtemplate */
"my_caps",
"audio/raw",
"format", GST_PROPS_STRING ("int"),
"channels", GST_PROPS_INT_RANGE (1, 6)
)
)
void
my_method (void)
{
GstPad *pad;
pad = gst_pad_new_from_template (GST_PAD_TEMPLATE_GET (my_template_factory), "sink");
...
}
</programlisting>
</para>
<para>
The following example shows you how to add the padtemplate to an elementfactory:
<programlisting>
gboolean
my_factory_init (GstPlugin *plugin)
{
GstElementFactory *factory;
factory = gst_element_factory_new ("my_factory", GST_TYPE_MYFACTORY, &gst_myfactory_details);
g_return_val_if_fail (factory != NULL, FALSE);
gst_element_factory_add_pad_template (factory, GST_PAD_TEMPLATE_GET (my_template_factory));
gst_plugin_add_feature (plugin, GST_PLUGIN_FEATURE (factory));
return TRUE;
}
</programlisting>
</para>
<!-- ##### SECTION See_Also ##### -->
<para>
#GstPad, #GstElementFactory
</para>
<!-- ##### ENUM GstPadPresence ##### -->
<para>
Indicates when this pad will become available.
</para>
@GST_PAD_ALWAYS: the pad is always available
@GST_PAD_SOMETIMES: the pad will become available depending on the media stream
@GST_PAD_REQUEST: th pad is only available on request with
gst_element_request_pad_by_name() or gst_element_request_compatible_pad().
<!-- ##### STRUCT GstPadTemplate ##### -->
<para>
The padtemplate object.
</para>
<!-- ##### ENUM GstPadTemplateFlags ##### -->
<para>
Flags for the padtemplate
</para>
@GST_PAD_TEMPLATE_FIXED: The padtemplate has no variable properties
@GST_PAD_TEMPLATE_FLAG_LAST: first flag that can be used by subclasses.
<!-- ##### MACRO GST_PAD_TEMPLATE_CAPS ##### -->
<para>
Get a handle to the padtemplate #GstCaps
</para>
@templ: the template to query
<!-- ##### MACRO GST_PAD_TEMPLATE_DIRECTION ##### -->
<para>
Get the direction of the padtemplate.
</para>
@templ: the template to query
<!-- ##### MACRO GST_PAD_TEMPLATE_NAME_TEMPLATE ##### -->
<para>
Get the nametemplate of the padtemplate.
</para>
@templ: the template to query
<!-- ##### MACRO GST_PAD_TEMPLATE_PRESENCE ##### -->
<para>
Get the presence of the padtemplate.
</para>
@templ: the template to query
<!-- ##### MACRO GST_PAD_TEMPLATE_IS_FIXED ##### -->
<para>
Check if the properties of the padtemplate are fixed
</para>
@templ: the template to query
<!-- ##### FUNCTION gst_pad_template_new ##### -->
<para>
</para>
@name_template:
@direction:
@presence:
@caps:
@Returns:
<!-- # Unused Parameters # -->
@Varargs:
<!-- ##### FUNCTION gst_pad_template_get_caps ##### -->
<para>
</para>
@templ:
@Returns:
<!-- ##### FUNCTION gst_pad_template_get_caps_by_name ##### -->
<para>
</para>
@templ:
@name:
@Returns:
<!-- ##### SIGNAL GstPadTemplate::pad-created ##### -->
<para>
This signal is fired when an element creates a pad from this
template.
</para>
@gstpadtemplate: the object which received the signal.
@arg1: The pad that was created.
|
