GstPadTemplate
Describe the media type of a pad.
Padtemplates describe the possible media types a pad or an elementfactory can
handle.
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.
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.
The following code example shows the code to create a pad from a padtemplate.
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");
...
}
The following example shows you how to add the padtemplate to an elementfactory:
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;
}
#GstPad, #GstElementFactory
Indicates when this pad will become available.
@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().
The padtemplate object.
Get a handle to the padtemplate #GstCaps
@templ: the template to query
Get the direction of the padtemplate.
@templ: the template to query
Get the nametemplate of the padtemplate.
@templ: the template to query
Get the presence of the padtemplate.
@templ: the template to query
Create a new padtemplate.
@padname: the nametemplate for the pads that will be created with this template
@dir: the direction of the pads.
@pres: the presence of the pads.
@...: the capabilities of this padtemplate usually created with GST_CAPS_NEW()
Create a factory for a padtemplate. This can be used if you only want one instance
of the padtemplate. Use GST_PAD_TEMPLATE_GET() to get the unique padtemplate.
@name: th name of the factory
@padname: the nametemplate of the pads
@dir: the direction of the pads.
@pres: the presence of the pads.
@...: the capabilities of this padtemplate, usually created with GST_CAPS_NEW()
Get the padtemplate of the factory created with GST_PAD_TEMPLATE_FACTORY()
@fact: the factory name to get the padtemplate from.
Check if the properties of the padtemplate are fixed
@templ: the template to query
@name_template:
@direction:
@presence:
@caps:
@Varargs:
@Returns:
@templ:
@Returns:
@templ:
@name:
@Returns:
This signal is fired when an element creates a pad from this
template.
@gstpadtemplate: the object which received the signal.
@arg1: The pad that was created.