Struct gstreamer::Bin

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

Bin is an element that can contain other Element, allowing them to be managed as a group. Pads from the child elements can be ghosted to the bin, see GhostPad. This makes the bin look like any other elements and enables creation of higher-level abstraction elements.

A new Bin is created with new(). Use a Pipeline instead if you want to create a toplevel bin because a normal bin doesn’t have a bus or handle clock distribution of its own.

After the bin has been created you will typically add elements to it with GstBinExt::add(). You can remove elements with GstBinExt::remove().

An element can be retrieved from a bin with GstBinExt::by_name(), using the elements name. GstBinExt::by_name_recurse_up() is mainly used for internal purposes and will query the parent bins when the element is not found in the current bin.

An iterator of elements in a bin can be retrieved with GstBinExtManual::iterate_elements(). Various other iterators exist to retrieve the elements in a bin.

gst_object_unref() is used to drop your reference to the bin.

The element-added signal is fired whenever a new element is added to the bin. Likewise the element-removed signal is fired whenever an element is removed from the bin.

A Bin internally intercepts every Message posted by its children and implements the following default behaviour for each of them:

• GST_MESSAGE_EOS: This message is only posted by sinks in the PLAYING state. If all sinks posted the EOS message, this bin will post and EOS message upwards.

• GST_MESSAGE_SEGMENT_START: Just collected and never forwarded upwards. The messages are used to decide when all elements have completed playback of their segment.

• GST_MESSAGE_SEGMENT_DONE: Is posted by Bin when all elements that posted a SEGMENT_START have posted a SEGMENT_DONE.

• GST_MESSAGE_DURATION_CHANGED: Is posted by an element that detected a change in the stream duration. The duration change is posted to the application so that it can refetch the new duration with a duration query.

Note that these messages can be posted before the bin is prerolled, in which case the duration query might fail.

Note also that there might be a discrepancy (due to internal buffering/queueing) between the stream being currently displayed and the returned duration query.

Applications might want to also query for duration (and changes) by listening to the GST_MESSAGE_STREAM_START message, signaling the active start of a (new) stream.

• GST_MESSAGE_CLOCK_LOST: This message is posted by an element when it can no longer provide a clock.

The default bin behaviour is to check if the lost clock was the one provided by the bin. If so and the bin is currently in the PLAYING state, the message is forwarded to the bin parent.

This message is also generated when a clock provider is removed from the bin. If this message is received by the application, it should PAUSE the pipeline and set it back to PLAYING to force a new clock distribution.

• GST_MESSAGE_CLOCK_PROVIDE: This message is generated when an element can provide a clock. This mostly happens when a new clock provider is added to the bin.

The default behaviour of the bin is to mark the currently selected clock as dirty, which will perform a clock recalculation the next time the bin is asked to provide a clock.

This message is never sent to the application but is forwarded to the parent of the bin.

• OTHERS: posted upwards.

A Bin implements the following default behaviour for answering to a Query:

• GST_QUERY_DURATION: The bin will forward the query to all sink elements contained within and will return the maximum value. If no sinks are available in the bin, the query fails.

• GST_QUERY_POSITION: The query is sent to all sink elements in the bin and the MAXIMUM of all values is returned. If no sinks are available in the bin, the query fails.

• OTHERS: the query is forwarded to all sink elements, the result of the first sink that answers the query successfully is returned. If no sink is in the bin, the query fails.

A Bin will by default forward any event sent to it to all sink ( EventTypeFlags::UPSTREAM ) or source ( EventTypeFlags::DOWNSTREAM ) elements depending on the event type.

If all the elements return true, the bin will also return true, else false is returned. If no elements of the required type are in the bin, the event handler will return true.

Properties

async-handling

If set to true, the bin will handle asynchronous state changes. This should be used only if the bin subclass is modifying the state of its children on its own.

Readable | Writeable

message-forward

Forward all children messages, even those that would normally be filtered by the bin. This can be interesting when one wants to be notified of the EOS state of individual elements, for example.

The messages are converted to an ELEMENT message with the bin as the source. The structure of the message is named GstBinForwarded and contains a field named message that contains the original forwarded Message.

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

deep-element-added

Will be emitted after the element was added to sub_bin.

deep-element-removed

Will be emitted after the element was removed from sub_bin.

do-latency

Will be emitted when the bin needs to perform latency calculations. This signal is only emitted for toplevel bins or when async-handling is enabled.

Only one signal handler is invoked. If no signals are connected, the default handler is invoked, which will query and distribute the lowest possible latency to all sinks.

Connect to this signal if the default latency calculations are not sufficient, like when you need different latencies for different sinks in the same pipeline.

element-added

Will be emitted after the element was added to the bin.

element-removed

Will be emitted after the element was removed from the bin.

Element

no-more-pads

This signals that the element will not generate more dynamic pads. Note that this signal will usually be emitted from the context of the streaming thread.

pad-added

a new Pad has been added to the element. Note that this signal will usually be emitted from the context of the streaming thread. Also keep in mind that if you add new elements to the pipeline in the signal handler you will need to set them to the desired target state with ElementExt::set_state() or ElementExt::sync_state_with_parent().

pad-removed

a Pad has been removed from the element

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

ChildProxy

child-added

Will be emitted after the object was added to the child_proxy.

child-removed

Will be emitted after the object was removed from the child_proxy.

Implements

GstBinExt, ElementExt, GstObjectExt, glib::ObjectExt, ChildProxyExt, ElementExtManual, ChildProxyExtManual

Implementations

impl Bin

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

impl Bin

pub fn new() -> Bin

Creates a new Bin object with a default name.

Use Bin::with_name() to create a Bin with a specific name. Use Bin::builder() for additional configuration. Creates a new bin with the given name.

name

the name of the new bin

Returns

a new Bin

pub fn with_name(name: &str) -> Bin

Creates a new Bin object with the specified name.

Use Bin::builder() for additional configuration.

pub fn builder() -> BinBuilder

Creates a new builder-pattern struct instance to construct Bin objects.

This method returns an instance of BinBuilder which can be used to create Bin objects.

Trait Implementations

impl Clone for Bin

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 Bin

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

Formats the value using the given formatter.

impl Default for Bin

fn default() -> Self

Returns the “default value” for a type.

impl HasParamSpec for Bin

type ParamSpec = ParamSpecObject

type SetValue = Bin

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

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

fn param_spec_builder() -> Self::BuilderFn

impl Hash for Bin

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: BinImpl> IsSubclassable<T> for Bin

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 Bin

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 Bin

type Parent = Element

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

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 Bin

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 Bin

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for Bin

impl IsA<Bin> for Pipeline

impl IsA<ChildProxy> for Bin

impl IsA<Element> for Bin

impl IsA<Object> for Bin

impl Send for Bin

impl Sync for Bin