Struct gstreamer::PadTemplate

pub struct PadTemplate { /* private fields */ }

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 Caps attached to it to describe the media type they are capable of dealing with. caps() 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 PadPresence 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 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 ElementExtManual::request_pad_simple() call to instantiate a pad from this template.

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

A padtemplate can be used to create a pad (see Pad::from_template() 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.

⚠️ The following code is in C ⚠️

  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:

⚠️ The following code is in C ⚠️

  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);
  }

Properties

caps

The capabilities of the pad described by the pad template.

Readable | Writeable | Construct Only

direction

The direction of the pad described by the pad template.

Readable | Writeable | Construct Only

gtype

The type of the pad described by the pad template.

Readable | Writeable | Construct Only

name-template

The name template of the pad template.

Readable | Writeable | Construct Only

presence

When the pad described by the pad template will become available.

Readable | Writeable | Construct Only

Object

name

Readable | Writeable | Construct

parent

The parent of the object. Please note, that when changing the ‘parent’ property, we don’t emit notify and deep-notify signals due to locking issues. In some cases one can use element-added or element-removed signals on the parent to achieve a similar effect.

Readable | Writeable

Signals

pad-created

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

Object

deep-notify

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.

Detailed

Implements

GstObjectExt, [trait@glib::ObjectExt]

GLib type: GObject with reference counted clone semantics.

Implementations

impl PadTemplate

pub fn new( name_template: &str, direction: PadDirection, presence: PadPresence, caps: &Caps, ) -> Result<PadTemplate, BoolError>

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 PadDirection of the template.

presence

the PadPresence of the pad.

caps

a Caps set for the template.

Returns

a new PadTemplate.

pub fn with_gtype( name_template: &str, direction: PadDirection, presence: PadPresence, caps: &Caps, pad_type: Type, ) -> Result<PadTemplate, BoolError>

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 PadDirection of the template.

presence

the PadPresence of the pad.

caps

a Caps set for the template.

pad_type

The GType of the pad to create

Returns

a new PadTemplate.

pub fn pad_created(&self, pad: &impl IsA<Pad>)

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

pad

the Pad that created it

pub fn connect_pad_created<F: Fn(&Self, &Pad) + Send + Sync + 'static>( &self, f: F, ) -> SignalHandlerId

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

pad

the pad that was created.

impl PadTemplate

pub fn from_static_pad_template_with_gtype( pad_template: &StaticPadTemplate, pad_type: Type, ) -> Result<PadTemplate, BoolError>

Converts a StaticPadTemplate into a PadTemplate with a type.

pad_template

the static pad template

pad_type

The GType of the pad to create

Returns

a new PadTemplate.

pub fn caps(&self) -> &Caps

Gets the capabilities of the pad template.

Returns

the Caps of the pad template. Unref after usage.

pub fn documentation_caps(&self) -> &Caps

See [set_documentation_caps()][Self::set_documentation_caps()].

Returns

The caps to document. For convenience, this will return caps() when no documentation caps were set.

pub fn direction(&self) -> PadDirection

pub fn gtype(&self) -> Type

pub fn name_template(&self) -> &str

pub fn presence(&self) -> PadPresence

pub fn builder<'a>( name_template: &'a str, direction: PadDirection, presence: PadPresence, caps: &'a Caps, ) -> PadTemplateBuilder<'a>

Trait Implementations

impl Clone for PadTemplate

fn clone(&self) -> Self

Makes a clone of this shared reference.

This increments the strong reference count of the object. Dropping the object will decrement it again.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PadTemplate

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl HasParamSpec for PadTemplate

type ParamSpec = ParamSpecObject

type SetValue = PadTemplate

Preferred value to be used as setter for the associated ParamSpec.

type BuilderFn = fn(_: &str) -> ParamSpecObjectBuilder<'_, PadTemplate>

fn param_spec_builder() -> Self::BuilderFn

impl Hash for PadTemplate

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Hashes the memory address of this object.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for PadTemplate

fn cmp(&self, other: &Self) -> Ordering

Comparison for two GObjects.

Compares the memory addresses of the provided objects.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl ParentClassIs for PadTemplate

type Parent = Object

impl<OT: ObjectType> PartialEq<OT> for PadTemplate

fn eq(&self, other: &OT) -> bool

Equality for two GObjects.

Two GObjects are equal if their memory addresses are equal.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<OT: ObjectType> PartialOrd<OT> for PadTemplate

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

Partial comparison for two GObjects.

Compares the memory addresses of the provided objects.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for PadTemplate

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for PadTemplate

impl IsA<Object> for PadTemplate

impl Send for PadTemplate

impl Sync for PadTemplate