GStreamer Core Reference Manual | |||
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#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, ...) #define GST_PAD_TEMPLATE_FACTORY (name, padname, dir, pres, ...) #define GST_PAD_TEMPLATE_GET (fact) #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); |
"pad-created" void user_function (GstPadTemplate *gstpadtemplate, gpointer arg1, gpointer user_data); |
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; } |
typedef enum { GST_PAD_ALWAYS, GST_PAD_SOMETIMES, GST_PAD_REQUEST } GstPadPresence; |
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(). |
#define GST_PAD_TEMPLATE_CAPS(templ) (((GstPadTemplate *)(templ))->caps) |
Get a handle to the padtemplate GstCaps
templ : | the template to query |
#define GST_PAD_TEMPLATE_DIRECTION(templ) (((GstPadTemplate *)(templ))->direction) |
Get the direction of the padtemplate.
templ : | the template to query |
#define GST_PAD_TEMPLATE_NAME_TEMPLATE(templ) (((GstPadTemplate *)(templ))->name_template) |
Get the nametemplate of the padtemplate.
templ : | the template to query |
#define GST_PAD_TEMPLATE_PRESENCE(templ) (((GstPadTemplate *)(templ))->presence) |
Get the presence of the padtemplate.
templ : | the template to query |
#define GST_PAD_TEMPLATE_NEW(padname, dir, pres, ...) |
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() |
#define GST_PAD_TEMPLATE_FACTORY(name, padname, dir, pres, ...) |
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() |
#define GST_PAD_TEMPLATE_GET(fact) (fact)() |
Get the padtemplate of the factory created with GST_PAD_TEMPLATE_FACTORY()
fact : | the factory name to get the padtemplate from. |
#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 |
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.
name_template : | the name template. |
direction : | the GstPadDirection of the template. |
presence : | the GstPadPresence of the pad. |
caps : | a GstCaps set for the template. |
... : | a NULL-terminated list of GstCaps. |
Returns : | a new GstPadTemplate. |
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. |
GstCaps* gst_pad_template_get_caps_by_name (GstPadTemplate *templ, const gchar *name); |
Gets the capability with the given name from this pad template.
templ : | a GstPadTemplate to get the capabilities of. |
name : | the name of the capability to get. |
Returns : | the GstCaps, or NULL if not found or in case of an error. |
void user_function (GstPadTemplate *gstpadtemplate, gpointer 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. |