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 gstreamer.Caps attached to it to describe the media type they are capable of dealing with. Pad.templateGetCaps 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 gstreamer.PadTemplate 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 Element.getRequestPad call to instantiate a pad from this template.

Padtemplates can be created with Pad.templateNew or with gst_static_pad_template_get (), which creates a gstreamer.PadTemplate from a gstreamer.StaticPadTemplate that can be filled with the convenient GST_STATIC_PAD_TEMPLATE() macro.

A padtemplate can be used to create a pad (see 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.

1 
2 GstStaticPadTemplate my_template =
3 GST_STATIC_PAD_TEMPLATE (
4 "sink",          // the name of the pad
5 GST_PAD_SINK,    // the direction of the pad
6 GST_PAD_ALWAYS,  // when this pad will be present
7 GST_STATIC_CAPS (        // the capabilities of the padtemplate
8 "audio/x-raw, "
9 "channels = (int) [ 1, 6 ]"
10 )
11 );
12 void
13 my_method (void)
14 {
15 GstPad *pad;
16 pad = gst_pad_new_from_static_template (&my_template, "sink");
17 ...
18 }

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:

1 
2 static void
3 my_element_class_init (GstMyElementClass *klass)
4 {
5 GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);
6 
7 gst_element_class_add_static_pad_template (gstelement_class, &my_template);
8 }

Constructors

this
this(GstPadTemplate* gstPadTemplate, bool ownedRef = false)

Sets our main struct and passes it to the parent class.

this
this(string nameTemplate, GstPadDirection direction, GstPadPresence presence, Caps caps)

Creates a new pad template with a name according to the given template and with the given arguments.

this
this(StaticPadTemplate padTemplate, GType padType)

Converts a gstreamer.StaticPadTemplate into a gstreamer.PadTemplate with a type.

this
this(string nameTemplate, GstPadDirection direction, GstPadPresence presence, Caps caps, GType padType)

Creates a new pad template with a name according to the given template and with the given arguments.

Members

Functions

addOnPadCreated
gulong addOnPadCreated(void delegate(Pad, PadTemplate) dlg, ConnectFlags connectFlags = cast(ConnectFlags)0)

This signal is fired when an element creates a pad from this template.

getCaps
Caps getCaps()

Gets the capabilities of the pad template.

getPadTemplateStruct
GstPadTemplate* getPadTemplateStruct(bool transferOwnership = false)

Get the main Gtk struct

getStruct
void* getStruct()

the main Gtk struct as a void*

padCreated
void padCreated(Pad pad)

Emit the pad-created signal for this template when created by this pad.

Static functions

getType
GType getType()

Variables

gstPadTemplate
GstPadTemplate* gstPadTemplate;

the main Gtk struct

Inherited Members

From ObjectGst

gstObject
GstObject* gstObject;

the main Gtk struct

getObjectGstStruct
GstObject* getObjectGstStruct(bool transferOwnership = false)

Get the main Gtk struct

getStruct
void* getStruct()

the main Gtk struct as a void*

getType
GType getType()
checkUniqueness
bool checkUniqueness(ListG 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(ObjectG object, ObjectGst orig, 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.

refSink
void* refSink(void* object)

Increase the reference count of object, and possibly remove the floating reference, if object has a floating reference.

replace
bool replace(ref ObjectGst oldobj, 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(ControlBinding binding)

Attach the gstreamer.ControlBinding to the object. If there already was a gstreamer.ControlBinding for this property it will be replaced.

defaultError
void defaultError(ErrorG error, string dbg)

A default error function that uses g_printerr() to display the error message and the optional debug sting..

getControlBinding
ControlBinding getControlBinding(string propertyName)

Gets the corresponding gstreamer.ControlBinding for the property. This should be unreferenced again after use.

getControlRate
GstClockTime getControlRate()

Obtain the control-rate for this object. Audio processing gstreamer.Element objects will use this rate to sub-divide their processing loop and call gst_object_sync_values() inbetween. The length of the processing segment should be up to control-rate nanoseconds.

getGValueArray
bool getGValueArray(string propertyName, GstClockTime timestamp, GstClockTime interval, Value[] values)

Gets a number of gobject.Values for the given controlled property starting at the requested time. The array values need to hold enough space for n_values of gobject.Value

getName
string getName()

Returns a copy of the name of object. Caller should g_free() the return value after usage. For a nameless object, this returns NULL, which you can safely g_free() as well.

getParent
ObjectGst getParent()

Returns the parent of object. This function increases the refcount of the parent object so you should gst_object_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
Value getValue(string propertyName, GstClockTime timestamp)

Gets the value for the given controlled property at the requested time.

getValueArray
bool getValueArray(string propertyName, GstClockTime timestamp, GstClockTime interval, uint nValues, void* values)

Gets a number of values for the given controlled property starting at the requested time. The array values need to hold enough space for n_values of the same type as the objects property's type.

hasActiveControlBindings
bool hasActiveControlBindings()

Check if the object has active controlled properties.

hasAncestor
bool hasAncestor(ObjectGst ancestor)

Check if object has an ancestor ancestor somewhere up in the hierarchy. One can e.g. check if a gstreamer.Element is inside a gstreamer.Pipeline

hasAsAncestor
bool hasAsAncestor(ObjectGst ancestor)

Check if object has an ancestor ancestor somewhere up in the hierarchy. One can e.g. check if a gstreamer.Element is inside a gstreamer.Pipeline

hasAsParent
bool hasAsParent(ObjectGst parent)

Check if parent is the parent of object. E.g. a gstreamer.Element can check if it owns a given gstreamer.Pad

doref
ObjectGst doref()

Increments the reference count on object. This function does not take the lock on object because it relies on atomic refcounting.

removeControlBinding
bool removeControlBinding(ControlBinding binding)

Removes the corresponding gstreamer.ControlBinding 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_sync_values() 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_sync_values() will do nothing.

setControlRate
void setControlRate(GstClockTime controlRate)

Change the control-rate for this object. Audio processing gstreamer.Element objects will use this rate to sub-divide their processing loop and call gst_object_sync_values() inbetween. 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(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_ref_sink()).

suggestNextSync
GstClockTime suggestNextSync()

Returns a suggestion for timestamps where buffers should be split to get best controller results.

syncValues
bool syncValues(GstClockTime timestamp)

Sets the properties of the object, according to the gstreamer.ControlSources 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.

unref
void unref()

Decrements the reference count on object. If reference count hits zero, destroy object. This function does not take the lock on object as it relies on atomic refcounting.

addOnDeepNotify
gulong addOnDeepNotify(void delegate(ObjectGst, ParamSpec, ObjectGst) dlg, ConnectFlags connectFlags = cast(ConnectFlags)0)

The deep notify signal is used to be notified of property changes. It is typically attached to the toplevel bin to receive notifications from all the elements contained in that bin.

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