GstPadTemplate
Name
GstPadTemplate -- Describe the media type of a pad.
Synopsis
#include <gst/gst.h>
enum GstPadPresence;
struct GstPadTemplate;
#define GST_PAD_TEMPLATE_CAPS (templ)
#define GST_PAD_TEMPLATE_DIRECTION (templ)
#define GST_PAD_TEMPLATE_NAME_TEMPLATE (templ)
#define GST_PAD_TEMPLATE_PRESENCE (templ)
#define GST_PAD_TEMPLATE_NEW (padname, dir, pres, a...)
#define GST_PAD_TEMPLATE_FACTORY (name, padname, dir, pres, a...)
#define GST_PAD_TEMPLATE_GET (fact)
#define GST_PAD_TEMPLATE_FIXED (templ)
#define GST_PAD_TEMPLATE_IS_FIXED (templ)
GstPadTemplate* gst_pad_template_new (const gchar *name_template,
GstPadDirection direction,
GstPadPresence presence,
GstCaps *caps,
...);
GstCaps* gst_pad_template_get_caps (GstPadTemplate *templ);
GstCaps* gst_pad_template_get_caps_by_name
(GstPadTemplate *templ,
const gchar *name);
|
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.
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;
}
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Details
enum GstPadPresence
typedef enum {
GST_PAD_ALWAYS,
GST_PAD_SOMETIMES,
GST_PAD_REQUEST
} GstPadPresence; |
Indicates when this pad will become available.
GST_PAD_TEMPLATE_CAPS()
#define GST_PAD_TEMPLATE_CAPS(templ) (((GstPadTemplate *)(templ))->caps) |
Get a handle to the padtemplate GstCaps
GST_PAD_TEMPLATE_DIRECTION()
#define GST_PAD_TEMPLATE_DIRECTION(templ) (((GstPadTemplate *)(templ))->direction) |
Get the direction of the padtemplate.
GST_PAD_TEMPLATE_NAME_TEMPLATE()
#define GST_PAD_TEMPLATE_NAME_TEMPLATE(templ) (((GstPadTemplate *)(templ))->name_template) |
Get the nametemplate of the padtemplate.
GST_PAD_TEMPLATE_PRESENCE()
#define GST_PAD_TEMPLATE_PRESENCE(templ) (((GstPadTemplate *)(templ))->presence) |
Get the presence of the padtemplate.
GST_PAD_TEMPLATE_NEW()
#define GST_PAD_TEMPLATE_NEW(padname, dir, pres, a...) |
Create a new padtemplate.
GST_PAD_TEMPLATE_FACTORY()
#define GST_PAD_TEMPLATE_FACTORY(name, padname, dir, pres, a...) |
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.
GST_PAD_TEMPLATE_GET()
#define GST_PAD_TEMPLATE_GET(fact) (fact)() |
Get the padtemplate of the factory created with GST_PAD_TEMPLATE_FACTORY()
GST_PAD_TEMPLATE_FIXED()
#define GST_PAD_TEMPLATE_FIXED(templ) (((GstPadTemplate *)(templ))->fixed) |
Get the flag indicating the properties are fixed from the template.
GST_PAD_TEMPLATE_IS_FIXED()
#define GST_PAD_TEMPLATE_IS_FIXED(templ) (GST_PAD_TEMPLATE_FIXED(templ) == TRUE) |
Check if the properties of the padtemplate are fixed
gst_pad_template_new ()
Creates a new pad template with a name according to the given template
and with the given arguments.
gst_pad_template_get_caps ()
Gets the capabilities of the pad template.
gst_pad_template_get_caps_by_name ()
Gets the capability with the given name from this pad template.
Signals
The "pad-created" signal
void user_function (GstPadTemplate *gstpadtemplate,
gpointer arg1,
gpointer user_data); |