Package org.freedesktop.gstreamer.gst

Class PadTemplate

java.lang.Object
io.github.jwharm.javagi.base.ProxyInstance
org.gnome.gobject.TypeInstance
org.gnome.gobject.GObject
org.gnome.gobject.InitiallyUnowned
org.freedesktop.gstreamer.gst.GstObject
org.freedesktop.gstreamer.gst.PadTemplate
All Implemented Interfaces:
Proxy
@Generated("io.github.jwharm.JavaGI") public class PadTemplate extends GstObject
Padtemplates describe the possible media types a pad or an elementfactory can handle. This allows for both inspection of handled types before loading the element plugin as well as identifying pads on elements that are not yet created (request or sometimes pads).

Pad and PadTemplates have GstCaps attached to it to describe the media type they are capable of dealing with. gst_pad_template_get_caps() or GST_PAD_TEMPLATE_CAPS() are used to get the caps of a padtemplate. It's not possible to modify the caps of a padtemplate after creation.

PadTemplates have a GstPadPresence property which identifies the lifetime of the pad and that can be retrieved with GST_PAD_TEMPLATE_PRESENCE(). Also the direction of the pad can be retrieved from the GstPadTemplate with GST_PAD_TEMPLATE_DIRECTION().

The GST_PAD_TEMPLATE_NAME_TEMPLATE () is important for GST_PAD_REQUEST pads because it has to be used as the name in the gst_element_request_pad_simple() call to instantiate a pad from this template.

Padtemplates can be created with gst_pad_template_new() or with gst_static_pad_template_get (), which creates a GstPadTemplate from a GstStaticPadTemplate that can be filled with the convenient GST_STATIC_PAD_TEMPLATE() macro.

A padtemplate can be used to create a pad (see gst_pad_new_from_template() or gst_pad_new_from_static_template ()) or to add to an element class (see gst_element_class_add_static_pad_template ()).

The following code example shows the code to create a pad from a padtemplate. 

  GstStaticPadTemplate my_template =
   GST_STATIC_PAD_TEMPLATE (
     "sink",          // the name of the pad
     GST_PAD_SINK,    // the direction of the pad
     GST_PAD_ALWAYS,  // when this pad will be present
     GST_STATIC_CAPS (        // the capabilities of the padtemplate
       "audio/x-raw, "
         "channels = (int) [ 1, 6 ]"
     )
   );
   void
   my_method (void)
   {
     GstPad *pad;
     pad = gst_pad_new_from_static_template (&my_template, "sink");
     ...
   }

The following example shows you how to add the padtemplate to an element class, this is usually done in the class_init of the class: 

  static void
   my_element_class_init (GstMyElementClass *klass)
   {
     GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);

     gst_element_class_add_static_pad_template (gstelement_class, &my_template);
   }