Bin

Object Hierarchy:

Description:

[ CCode ( type_id = "gst_bin_get_type ()" ) ]
public class Bin : Element, ChildProxy

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 Bin. 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 add. You can remove elements with remove.

An element can be retrieved from a bin with get_by_name, using the elements name. get_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 iterate_elements . Various other iterators exist to retrieve the elements in a bin.

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:

* 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.

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

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

* 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 STREAM_START message, signaling the active start of a (new) stream.

* 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.

* 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:

* 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.

* 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 ( UPSTREAM ) or source ( 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.

All known sub-classes:

Pipeline

Namespace: Gst

Package: gstreamer-1.0

Content:

Properties:

public bool async_handling { get; set; }
If set to true, the bin will handle asynchronous state changes.
public bool message_forward { get; set; }
Forward all children messages, even those that would normally be filtered by the bin.

Creation methods:

public Bin (string? name)
Creates a new bin with the given name.

Methods:

public bool add (Element element)
Adds the given element to the bin.
public virtual bool add_element (Element element)
Method to add an element to the bin.
public void add_many (Element[] elements)
Adds a null-terminated list of elements to a bin.
public Pad? find_unlinked_pad (PadDirection direction)
Recursively looks for elements with an unlinked pad of the given direction within the specified bin and returns an unlinked pad if one is found, or null otherwise.
public Element? get_by_interface (Type iface)
Looks for an element inside the bin that implements the given interface.
public Element? get_by_name (string name)
Gets the element with the given name from a bin.
public Element? get_by_name_recurse_up (string name)
Gets the element with the given name from this bin.
public ElementFlags get_suppressed_flags ()
public virtual void handle_message (owned Message message)
Method to handle a message from the children.
public Iterator? iterate_all_by_element_factory_name (string factory_name)
Looks for all elements inside the bin with the given element factory name.
public Iterator? iterate_all_by_interface (Type iface)
Looks for all elements inside the bin that implements the given interface.
public Iterator? iterate_elements ()
Gets an iterator for the elements in this bin.
public Iterator? iterate_recurse ()
Gets an iterator for the elements in this bin.
public Iterator? iterate_sinks ()
Gets an iterator for all elements in the bin that have the SINK flag set.
public Iterator? iterate_sorted ()
Gets an iterator for the elements in this bin in topologically sorted order.
public Iterator? iterate_sources ()
Gets an iterator for all elements in the bin that have the SOURCE flag set.
public bool recalculate_latency ()
Queries this for the current latency and reconfigures this latency on all the elements using a LATENCY event.
public bool remove (Element element)
Removes the element from the bin, unparenting it as well.
public virtual bool remove_element (Element element)
Method to remove an element from the bin.
public void remove_many (Element[] elements)
Removes a list of elements from a bin.
public void set_suppressed_flags (ElementFlags flags)
Suppresses the given flags on the bin.
public bool sync_children_states ()
Synchronizes the state of every child of this with the state of this.

Signals:

public virtual signal void deep_element_added (Bin sub_bin, Element child)
Will be emitted after the element was added to sub_bin.
public virtual signal void deep_element_removed (Bin sub_bin, Element child)
Will be emitted after the element was removed from sub_bin.
public virtual signal bool do_latency ()
Will be emitted when the bin needs to perform latency calculations.
public virtual signal void element_added (Element child)
Will be emitted after the element was added to the bin.
public virtual signal void element_removed (Element child)
Will be emitted after the element was removed from the bin.

Fields:

public Bus child_bus
public List<Element> children
public uint32 children_cookie
public bool clock_dirty
public Element clock_provider
public List<Message> messages
public int numchildren
public bool polling
public Clock provided_clock
public bool state_dirty

Inherited Members:

All known members inherited from class Gst.Element

All known members inherited from class Gst.Object

All known members inherited from class GLib.Object

All known members inherited from interface Gst.ChildProxy