Struct gstreamer::Pad

#[repr(transparent)]
pub struct Pad { /* private fields */ }

A Element is linked to other elements via “pads”, which are extremely light-weight generic link points.

Pads have a PadDirection, source pads produce data, sink pads consume data.

Pads are typically created from a PadTemplate with from_template() and are then added to a Element. This usually happens when the element is created but it can also happen dynamically based on the data that the element is processing or based on the pads that the application requests.

Pads without pad templates can be created with new(), which takes a direction and a name as an argument. If the name is None, then a guaranteed unique name will be assigned to it.

A Element creating a pad will typically use the various gst_pad_set_*_function() calls to register callbacks for events, queries or dataflow on the pads.

gst_pad_get_parent() will retrieve the Element that owns the pad.

After two pads are retrieved from an element by ElementExt::static_pad(), the pads can be linked with PadExt::link(). (For quick links, you can also use ElementExtManual::link(), which will make the obvious link for you if it’s straightforward.). Pads can be unlinked again with PadExt::unlink(). PadExt::peer() can be used to check what the pad is linked to.

Before dataflow is possible on the pads, they need to be activated with PadExt::set_active().

PadExtManual::query() and PadExtManual::peer_query() can be used to query various properties of the pad and the stream.

To send a Event on a pad, use PadExtManual::send_event() and PadExtManual::push_event(). Some events will be sticky on the pad, meaning that after they pass on the pad they can be queried later with PadExtManual::sticky_event() and PadExtManual::sticky_events_foreach(). PadExt::current_caps() and PadExt::has_current_caps() are convenience functions to query the current sticky CAPS event on a pad.

GstElements will use PadExt::push() and PadExtManual::pull_range() to push out or pull in a buffer.

The dataflow, events and queries that happen on a pad can be monitored with probes that can be installed with PadExtManual::add_probe(). PadExt::is_blocked() can be used to check if a block probe is installed on the pad. PadExt::is_blocking() checks if the blocking probe is currently blocking the pad. PadExtManual::remove_probe() is used to remove a previously installed probe and unblock blocking probes if any.

Pad have an offset that can be retrieved with PadExt::offset(). This offset will be applied to the running_time of all data passing over the pad. PadExt::set_offset() can be used to change the offset.

Convenience functions exist to start, pause and stop the task on a pad with PadExtManual::start_task(), PadExt::pause_task() and PadExt::stop_task() respectively.

Properties

caps

Readable

direction

Readable | Writeable | Construct Only

offset

The offset that will be applied to the running time of the pad.

Readable | Writeable

template

Readable | Writeable

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

linked

Signals that a pad has been linked to the peer pad.

unlinked

Signals that a pad has been unlinked from the peer pad.

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

PadExt, GstObjectExt, glib::ObjectExt, PadExtManual

Implementations

impl Pad

pub const NONE: Option<&'static Pad> = None

impl Pad

pub fn new(name: Option<&str>, direction: PadDirection) -> Self

pub fn builder(name: Option<&str>, direction: PadDirection) -> PadBuilder<Self>

pub fn from_static_template(
    templ: &StaticPadTemplate,
    name: Option<&str>
) -> Self

pub fn builder_with_static_template(
    templ: &StaticPadTemplate,
    name: Option<&str>
) -> PadBuilder<Self>

pub fn from_template(templ: &PadTemplate, name: Option<&str>) -> Self

pub fn builder_with_template(
    templ: &PadTemplate,
    name: Option<&str>
) -> PadBuilder<Self>

pub fn query_default<O: IsA<Pad>>(
    pad: &O,
    parent: Option<&impl IsA<Object>>,
    query: &mut QueryRef
) -> bool

pub fn event_default<O: IsA<Pad>>(
    pad: &O,
    parent: Option<&impl IsA<Object>>,
    event: impl Into<Event>
) -> bool

pub fn iterate_internal_links_default<O: IsA<Pad>>(
    pad: &O,
    parent: Option<&impl IsA<Object>>
) -> Iterator<Pad>

Trait Implementations

impl Clone for Pad

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Pad

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

Formats the value using the given formatter.

impl HasParamSpec for Pad

type ParamSpec = ParamSpecObject

type SetValue = Pad

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

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

fn param_spec_builder() -> Self::BuilderFn

impl Hash for Pad

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

Feeds this value into the given Hasher.

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<T: PadImpl> IsSubclassable<T> for Pad

fn class_init(klass: &mut Class<Self>)

Override the virtual methods of this class for the given subclass and do other class initialization.

fn instance_init(instance: &mut InitializingObject<T>)

Instance specific initialization.

impl Ord for Pad

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

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl ParentClassIs for Pad

type Parent = Object

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

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

This method tests for self and other values to be equal, and is used by ==.

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

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

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

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

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

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

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

This method tests greater than (for self and other) and is used by the > operator.

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

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

impl StaticType for Pad

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for Pad

impl IsA<Object> for Pad

impl IsA<Pad> for GhostPad

impl IsA<Pad> for ProxyPad

impl Send for Pad

impl Sync for Pad