#[repr(transparent)]pub struct Pad { /* private fields */ }
Expand description
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
Implementations§
source§impl Pad
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§
source§impl HasParamSpec for Pad
impl HasParamSpec for Pad
source§impl<T: PadImpl> IsSubclassable<T> for Pad
impl<T: PadImpl> IsSubclassable<T> for Pad
source§fn class_init(klass: &mut Class<Self>)
fn class_init(klass: &mut Class<Self>)
source§fn instance_init(instance: &mut InitializingObject<T>)
fn instance_init(instance: &mut InitializingObject<T>)
source§impl Ord for Pad
impl Ord for Pad
source§impl<OT: ObjectType> PartialEq<OT> for Pad
impl<OT: ObjectType> PartialEq<OT> for Pad
source§impl<OT: ObjectType> PartialOrd<OT> for Pad
impl<OT: ObjectType> PartialOrd<OT> for Pad
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moresource§impl StaticType for Pad
impl StaticType for Pad
source§fn static_type() -> Type
fn static_type() -> Type
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
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