GstPadTemplate

## GstPadTemplate GstPadTemplate — Describe the media type of a pad. |

## Synopsis

    #include <gst/gst.h>

                GstPadTemplate;
                GstStaticPadTemplate;
    #define     GST_IS_GHOST_PAD_FAST           (obj)
    #define     GST_IS_PAD_FAST                 (obj)
    #define     GST_PAD_TEMPLATE_NAME_TEMPLATE  (templ)
    #define     GST_PAD_TEMPLATE_DIRECTION      (templ)
    #define     GST_PAD_TEMPLATE_PRESENCE       (templ)
    #define     GST_PAD_TEMPLATE_CAPS           (templ)
    #define     GST_PAD_TEMPLATE_IS_FIXED       (templ)
    enum        GstPadTemplateFlags;
    GstPadTemplate* gst_pad_template_new        (const gchar *name_template,
                                                 GstPadDirection direction,
                                                 GstPadPresence presence,
                                                 GstCaps *caps);
    GstPadTemplate* gst_static_pad_template_get (GstStaticPadTemplate *pad_template);
    const GstCaps* gst_pad_template_get_caps    (GstPadTemplate *templ);
    const GstCaps* gst_pad_template_get_caps_by_name
                                                (GstPadTemplate *templ,
                                                 const gchar *name);

## Object Hierarchy

      GObject
       +----GstObject
             +----GstPadTemplate

## Signal Prototypes

    "pad-created"
                void        user_function      (GstPadTemplate *gstpadtemplate,
                                                GstPad *arg1,
                                                gpointer user_data);

## Description

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.

Example 6. 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-int, "
            "channels = (int) [ 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;
      }

## Details

### GstPadTemplate

    typedef struct _GstPadTemplate GstPadTemplate;

The padtemplate object.

### GstStaticPadTemplate

    typedef struct {
      gchar           *name_template;
      GstPadDirection  direction;
      GstPadPresence   presence;
      GstStaticCaps   static_caps;
    } GstStaticPadTemplate;

### GST_IS_GHOST_PAD_FAST()

    #define GST_IS_GHOST_PAD_FAST(obj)	(G_OBJECT_TYPE(obj) == GST_TYPE_GHOST_PAD)

`obj` : |

### GST_IS_PAD_FAST()

    #define     GST_IS_PAD_FAST(obj)

`obj` : |

### GST_PAD_TEMPLATE_NAME_TEMPLATE()

    #define GST_PAD_TEMPLATE_NAME_TEMPLATE(templ)	(((GstPadTemplate *)(templ))->name_template)

Get the nametemplate of the padtemplate.

`templ` : | the template to query

### GST_PAD_TEMPLATE_DIRECTION()

    #define GST_PAD_TEMPLATE_DIRECTION(templ)	(((GstPadTemplate *)(templ))->direction)

Get the direction of the padtemplate.

`templ` : | the template to query

### GST_PAD_TEMPLATE_PRESENCE()

    #define GST_PAD_TEMPLATE_PRESENCE(templ)	(((GstPadTemplate *)(templ))->presence)

Get the presence of the padtemplate.

`templ` : | the template to query

### GST_PAD_TEMPLATE_CAPS()

    #define GST_PAD_TEMPLATE_CAPS(templ)		(((GstPadTemplate *)(templ))->caps)

Get a handle to the padtemplate GstCaps

`templ` : | the template to query

### GST_PAD_TEMPLATE_IS_FIXED()

    #define GST_PAD_TEMPLATE_IS_FIXED(templ)	(GST_FLAG_IS_SET(templ, GST_PAD_TEMPLATE_FIXED))

Check if the properties of the padtemplate are fixed

`templ` : | the template to query

### enum GstPadTemplateFlags

    typedef enum {
      GST_PAD_TEMPLATE_FIXED	= GST_OBJECT_FLAG_LAST,

      GST_PAD_TEMPLATE_FLAG_LAST	= GST_OBJECT_FLAG_LAST + 4
    } GstPadTemplateFlags;

Flags for the padtemplate

`GST_PAD_TEMPLATE_FIXED` | the padtemplate has no variable properties
`GST_PAD_TEMPLATE_FLAG_LAST` | first flag that can be used by subclasses.

### gst_pad_template_new ()

    GstPadTemplate* gst_pad_template_new        (const gchar *name_template,
                                                 GstPadDirection direction,
                                                 GstPadPresence presence,
                                                 GstCaps *caps);

Creates a new pad template with a name according to the given template and with the given arguments. This functions takes ownership of the provided caps, so be sure to not use them afterwards.

`name_template` : | the name template.
`direction` : | the GstPadDirection of the template.
`presence` : | the GstPadPresence of the pad.
`caps` : | a GstCaps set for the template. The caps are taken ownership of.
Returns : | a new GstPadTemplate.

### gst_static_pad_template_get ()

    GstPadTemplate* gst_static_pad_template_get (GstStaticPadTemplate *pad_template);

Converts a GstStaticPadTemplate into a GstPadTemplate.

`pad_template` : | the static pad template
Returns : | a new GstPadTemplate.

### gst_pad_template_get_caps ()

    const GstCaps* gst_pad_template_get_caps    (GstPadTemplate *templ);

Gets the capabilities of the pad template.

`templ` : | a GstPadTemplate to get capabilities of.
Returns : | the GstCaps of the pad template. If you need to keep a reference to the caps, make a copy (see `gst_caps_copy()`).

### gst_pad_template_get_caps_by_name ()

    const GstCaps* gst_pad_template_get_caps_by_name
                                                (GstPadTemplate *templ,
                                                 const gchar *name);

### Warning

`gst_pad_template_get_caps_by_name` is deprecated and should not be used in newly-written code.

Gets the capability with the given name from `templ`.

`templ` : | a GstPadTemplate to get the capabilities of.
`name` : | the name of the capability to get.
Returns : | the GstCaps of this pad template, or NULL if not found. If you intend to keep a reference on the caps, make a copy (see `gst_caps_copy()`).

## Signals

### The "pad-created" signal

    void        user_function                  (GstPadTemplate *gstpadtemplate,
                                                GstPad *arg1,
                                                gpointer user_data);

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.
`user_data` : | user data set when the signal handler was connected.

## See Also

GstPad, GstElementFactory