PadTemplate

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.PadTemplate.getCaps 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.Element.requestPadSimple call to instantiate a pad from this template.

Padtemplates can be created with gst.pad_template.PadTemplate.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.Pad.newFromTemplate 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);
}

class PadTemplate : ObjectGst {

this(string nameTemplate, gst.types.PadDirection direction, gst.types.PadPresence presence, gst.caps.Caps caps);

static gst.pad_template.PadTemplate newFromStaticPadTemplateWithGtype(gst.static_pad_template.StaticPadTemplate padTemplate, gobject.types.GType padType);

static gst.pad_template.PadTemplate newWithGtype(string nameTemplate, gst.types.PadDirection direction, gst.types.PadPresence presence, gst.caps.Caps caps, gobject.types.GType padType);

gst.caps.Caps getCaps();

gst.caps.Caps getDocumentationCaps();

void padCreated(gst.pad.Pad pad);

void setDocumentationCaps(gst.caps.Caps caps);

ulong connectPadCreated(T callback, Flag!"After" after);

}

Constructors

this this(string nameTemplate, gst.types.PadDirection direction, gst.types.PadPresence presence, gst.caps.Caps caps): Creates a new pad template with a name according to the given template and with the given arguments.

Members

Functions

connectPadCreated ulong connectPadCreated(T callback, Flag!"After" after): Connect to PadCreated signal.
getCaps gst.caps.Caps getCaps(): Gets the capabilities of the pad template.
getDocumentationCaps gst.caps.Caps getDocumentationCaps(): See gst.pad_template.PadTemplate.setDocumentationCaps.
padCreated void padCreated(gst.pad.Pad pad): Emit the pad-created signal for this template when created by this pad.
setDocumentationCaps void setDocumentationCaps(gst.caps.Caps caps): Certain elements will dynamically construct the caps of their pad templates. In order not to let environment-specific information into the documentation, element authors should use this method to expose "stable" caps to the reader.

Static functions

newFromStaticPadTemplateWithGtype gst.pad_template.PadTemplate newFromStaticPadTemplateWithGtype(gst.static_pad_template.StaticPadTemplate padTemplate, gobject.types.GType padType): Converts a #GstStaticPadTemplate into a #GstPadTemplate with a type.
newWithGtype gst.pad_template.PadTemplate newWithGtype(string nameTemplate, gst.types.PadDirection direction, gst.types.PadPresence presence, gst.caps.Caps caps, gobject.types.GType padType): Creates a new pad template with a name according to the given template and with the given arguments.

Inherited Members

From ObjectGst

checkUniqueness bool checkUniqueness(gst.object.ObjectGst[] list, string name): Checks to see if there is any object named name in list. This function does not do any locking of any kind. You might want to protect the provided list with the lock of the owner of the list. This function will lock each #GstObject in the list to compare the name, so be careful when passing a list with a locked object.
defaultDeepNotify void defaultDeepNotify(gobject.object.ObjectG object, gst.object.ObjectGst orig, gobject.param_spec.ParamSpec pspec, string[] excludedProps): A default deep_notify signal callback for an object. The user data should contain a pointer to an array of strings that should be excluded from the notify. The default handler will print the new value of the property using g_print.
replace bool replace(gst.object.ObjectGst oldobj, gst.object.ObjectGst newobj): Atomically modifies a pointer to point to a new object. The reference count of oldobj is decreased and the reference count of newobj is increased.
addControlBinding bool addControlBinding(gst.control_binding.ControlBinding binding): Attach the #GstControlBinding to the object. If there already was a #GstControlBinding for this property it will be replaced.
defaultError void defaultError(glib.error.ErrorG error, string debug_): A default error function that uses glib.global.printerr to display the error message and the optional debug string..
getControlBinding gst.control_binding.ControlBinding getControlBinding(string propertyName): Gets the corresponding #GstControlBinding for the property. This should be unreferenced again after use.
getControlRate gst.types.ClockTime getControlRate(): Obtain the control-rate for this object. Audio processing #GstElement objects will use this rate to sub-divide their processing loop and call gst.object.ObjectGst.syncValues in between. The length of the processing segment should be up to control-rate nanoseconds.
getGValueArray bool getGValueArray(string propertyName, gst.types.ClockTime timestamp, gst.types.ClockTime interval, gobject.value.Value[] values): Gets a number of #GValues for the given controlled property starting at the requested time. The array values need to hold enough space for n_values of #GValue.
getName string getName(): Returns a copy of the name of object. Caller should glib.global.gfree the return value after usage. For a nameless object, this returns null, which you can safely glib.global.gfree as well.
getParent gst.object.ObjectGst getParent(): Returns the parent of object. This function increases the refcount of the parent object so you should gst.object.ObjectGst.unref it after usage.
getPathString string getPathString(): Generates a string describing the path of object in the object hierarchy. Only useful (or used) for debugging.
getValue gobject.value.Value getValue(string propertyName, gst.types.ClockTime timestamp): Gets the value for the given controlled property at the requested time.
hasActiveControlBindings bool hasActiveControlBindings(): Check if the object has active controlled properties.
hasAncestor bool hasAncestor(gst.object.ObjectGst ancestor): Check if object has an ancestor ancestor somewhere up in the hierarchy. One can e.g. check if a #GstElement is inside a #GstPipeline.
hasAsAncestor bool hasAsAncestor(gst.object.ObjectGst ancestor): Check if object has an ancestor ancestor somewhere up in the hierarchy. One can e.g. check if a #GstElement is inside a #GstPipeline.
hasAsParent bool hasAsParent(gst.object.ObjectGst parent): Check if parent is the parent of object. E.g. a #GstElement can check if it owns a given #GstPad.
removeControlBinding bool removeControlBinding(gst.control_binding.ControlBinding binding): Removes the corresponding #GstControlBinding. If it was the last ref of the binding, it will be disposed.
setControlBindingDisabled void setControlBindingDisabled(string propertyName, bool disabled): This function is used to disable the control bindings on a property for some time, i.e. gst.object.ObjectGst.syncValues will do nothing for the property.
setControlBindingsDisabled void setControlBindingsDisabled(bool disabled): This function is used to disable all controlled properties of the object for some time, i.e. gst.object.ObjectGst.syncValues will do nothing.
setControlRate void setControlRate(gst.types.ClockTime controlRate): Change the control-rate for this object. Audio processing #GstElement objects will use this rate to sub-divide their processing loop and call gst.object.ObjectGst.syncValues in between. The length of the processing segment should be up to control-rate nanoseconds.
setName bool setName(string name): Sets the name of object, or gives object a guaranteed unique name (if name is null). This function makes a copy of the provided name, so the caller retains ownership of the name it sent.
setParent bool setParent(gst.object.ObjectGst parent): Sets the parent of object to parent. The object's reference count will be incremented, and any floating reference will be removed (see gst.object.ObjectGst.refSink).
suggestNextSync gst.types.ClockTime suggestNextSync(): Returns a suggestion for timestamps where buffers should be split to get best controller results.
syncValues bool syncValues(gst.types.ClockTime timestamp): Sets the properties of the object, according to the #GstControlSources that (maybe) handle them and for the given timestamp.
unparent void unparent(): Clear the parent of object, removing the associated reference. This function decreases the refcount of object.
connectDeepNotify ulong connectDeepNotify(string detail, T callback, Flag!"After" after): Connect to DeepNotify signal.

gst pad_template classes

PadTemplate