Class Bin

java.lang.Object
org.javagi.base.ProxyInstance
org.gnome.gobject.TypeInstance
org.gnome.gobject.GObject
org.gnome.gobject.InitiallyUnowned
org.freedesktop.gstreamer.gst.GstObject
org.freedesktop.gstreamer.gst.Element
org.freedesktop.gstreamer.gst.Bin
All Implemented Interfaces:
ChildProxy, Proxy
Direct Known Subclasses:
Pipeline
@Generated("org.javagi.JavaGI") public class Bin extends Element implements ChildProxy

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

A new GstBin is created with gst_bin_new(). Use a GstPipeline 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 gst_bin_add(). You can remove elements with gst_bin_remove().

An element can be retrieved from a bin with gst_bin_get_by_name(), using the elements name. gst_bin_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 gst_bin_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 GstBin::element-added signal is fired whenever a new element is added to the bin. Likewise the GstBin::element-removed signal is fired whenever an element is removed from the bin.

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

  • MessageType.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.

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

  • MessageType.SEGMENT_DONE: Is posted by GstBin when all elements that posted a SEGMENT_START have posted a SEGMENT_DONE.

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

  • MessageType.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.

  • MessageType.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 GstBin implements the following default behaviour for answering to a GstQuery:

  • QueryType.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.

  • QueryType.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 GstBin 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.

  • Constructor Details

    • Bin

      public Bin(MemorySegment address)
      Create a Bin instance for the provided memory address.
      Parameters:
      address - the memory address of the native object

    • Bin

      public Bin(@Nullable String name)
      Creates a new bin with the given name.
      Parameters:
      name - the name of the new bin

    • Bin

      public Bin()
      Create a new Bin.

  • Method Details

    • getType

      public static @Nullable Type getType()
      Get the GType of the Bin class.
      Returns:
      the GType

    • getMemoryLayout

      public static MemoryLayout getMemoryLayout()
      The memory layout of the native struct.
      Returns:
      the memory layout

    • asParent

      protected Bin asParent()
      Return this instance as if it were its parent type. Comparable to the Java super keyword, but ensures the parent typeclass is also used in native code.
      Overrides:
      asParent in class Element
      Returns:
      the instance as if it were its parent type

    • add

      public boolean add(Element element)

      Adds the given element to the bin. Sets the element's parent, and thus takes ownership of the element. An element can only be added to one bin.

      If the element's pads are linked to other pads, the pads will be unlinked before the element is added to the bin.

      When you add an element to an already-running pipeline, you will have to take care to set the state of the newly-added element to the desired state (usually PLAYING or PAUSED, same you set the pipeline to originally) with gst_element_set_state(), or use gst_element_sync_state_with_parent(). The bin or pipeline will not take care of this for you.

      Parameters:
      element - the GstElement to add
      Returns:
      true if the element could be added, false if the bin does not want to accept the element.

    • addMany

      public void addMany(Element element1, Object... varargs)
      Adds a null-terminated list of elements to a bin. This function is equivalent to calling gst_bin_add() for each member of the list. The return value of each gst_bin_add() is ignored.
      Parameters:
      element1 - the GstElement element to add to the bin
      varargs - additional elements to add to the bin

    • findUnlinkedPad

      public @Nullable Pad findUnlinkedPad(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. If a pad is found, the caller owns a reference to it and should use gst_object_unref() on the pad when it is not needed any longer.
      Parameters:
      direction - whether to look for an unlinked source or sink pad
      Returns:
      unlinked pad of the given direction.

    • getByInterface

      public @Nullable Element getByInterface(Type iface)
      Looks for an element inside the bin that implements the given interface. If such an element is found, it returns the element. You can cast this element to the given interface afterwards. If you want all elements that implement the interface, use gst_bin_iterate_all_by_interface(). This function recurses into child bins.
      Parameters:
      iface - the GType of an interface
      Returns:
      A GstElement inside the bin implementing the interface

    • getByName

      public @Nullable Element getByName(String name)
      Gets the element with the given name from a bin. This function recurses into child bins.
      Parameters:
      name - the element name to search for
      Returns:
      the GstElement with the given name

    • getByNameRecurseUp

      public @Nullable Element getByNameRecurseUp(String name)
      Gets the element with the given name from this bin. If the element is not found, a recursion is performed on the parent bin.
      Parameters:
      name - the element name to search for
      Returns:
      the GstElement with the given name

    • getSuppressedFlags

      public Set<ElementFlags> getSuppressedFlags()

    • iterateAllByElementFactoryName

      public @Nullable Iterator iterateAllByElementFactoryName(String factoryName)
      Looks for all elements inside the bin with the given element factory name. The function recurses inside child bins. The iterator will yield a series of GstElement.
      Parameters:
      factoryName - the name of the GstElementFactory
      Returns:
      a GstIterator of GstElement for all elements in the bin with the given element factory name
      Since:
      1.18

    • iterateAllByInterface

      public @Nullable Iterator iterateAllByInterface(Type iface)
      Looks for all elements inside the bin that implements the given interface. You can safely cast all returned elements to the given interface. The function recurses inside child bins. The iterator will yield a series of GstElement.
      Parameters:
      iface - the GType of an interface
      Returns:
      a GstIterator of GstElement for all elements in the bin implementing the given interface

    • iterateElements

      public @Nullable Iterator iterateElements()
      Gets an iterator for the elements in this bin.
      Returns:
      a GstIterator of GstElement

    • iterateRecurse

      public @Nullable Iterator iterateRecurse()
      Gets an iterator for the elements in this bin. This iterator recurses into GstBin children.
      Returns:
      a GstIterator of GstElement

    • iterateSinks

      public @Nullable Iterator iterateSinks()
      Gets an iterator for all elements in the bin that have the GST_ELEMENT_FLAG_SINK flag set.
      Returns:
      a GstIterator of GstElement

    • iterateSorted

      public @Nullable Iterator iterateSorted()

      Gets an iterator for the elements in this bin in topologically sorted order. This means that the elements are returned from the most downstream elements (sinks) to the sources.

      This function is used internally to perform the state changes of the bin elements and for clock selection.

      Returns:
      a GstIterator of GstElement

    • iterateSources

      public @Nullable Iterator iterateSources()
      Gets an iterator for all elements in the bin that have the GST_ELEMENT_FLAG_SOURCE flag set.
      Returns:
      a GstIterator of GstElement

    • recalculateLatency

      public boolean recalculateLatency()

      Queries this Bin for the current latency and reconfigures this latency on all the elements using a LATENCY event.

      This method is typically called on the pipeline when a GST_MESSAGE_LATENCY is posted on the bus.

      This function simply emits the GstBin::do-latency signal so any custom latency calculations will be performed.

      Returns:
      true if the latency could be queried and reconfigured.

    • remove

      public boolean remove(Element element)

      Removes the element from the bin, unparenting it as well. Unparenting the element means that the element will be dereferenced, so if the bin holds the only reference to the element, the element will be freed in the process of removing it from the bin. If you want the element to still exist after removing, you need to call gst_object_ref() before removing it from the bin.

      If the element's pads are linked to other pads, the pads will be unlinked before the element is removed from the bin.

      Parameters:
      element - the GstElement to remove
      Returns:
      true if the element could be removed, false if the bin does not want to remove the element.

    • removeMany

      public void removeMany(Element element1, Object... varargs)
      Removes a list of elements from a bin. This function is equivalent to calling gst_bin_remove() with each member of the list.
      Parameters:
      element1 - the first GstElement to remove from the bin
      varargs - null-terminated list of elements to remove from the bin

    • setSuppressedFlags

      public void setSuppressedFlags(Set<ElementFlags> flags)
      Suppresses the given flags on the bin. GstElementFlags of a child element are propagated when it is added to the bin. When suppressed flags are set, those specified flags will not be propagated to the bin.
      Parameters:
      flags - the GstElementFlags to suppress
      Since:
      1.10

    • setSuppressedFlags

      public void setSuppressedFlags(ElementFlags... flags)
      Suppresses the given flags on the bin. GstElementFlags of a child element are propagated when it is added to the bin. When suppressed flags are set, those specified flags will not be propagated to the bin.
      Parameters:
      flags - the GstElementFlags to suppress
      Since:
      1.10

    • syncChildrenStates

      public boolean syncChildrenStates()
      Synchronizes the state of every child of this Bin with the state of bin. See also gst_element_sync_state_with_parent().
      Returns:
      true if syncing the state was successful for all children, otherwise false.
      Since:
      1.6

    • addElement

      protected boolean addElement(Element element)
      Method to add an element to the bin.
      Parameters:
      element - the element to be added
      Returns:
      true if the element was added

    • deepElementAdded

      protected void deepElementAdded(Bin subBin, Element child)
      Method called when an element was added somewhere in the bin hierarchy.
      Parameters:
      subBin - the GstBin to which the element was added
      child - the element that was added

    • deepElementRemoved

      protected void deepElementRemoved(Bin subBin, Element child)
      Method called when an element was removed somewhere in the bin hierarchy.
      Parameters:
      subBin - the GstBin from which the element was removed
      child - the element that was removed

    • doLatency

      protected boolean doLatency()

    • elementAdded

      protected void elementAdded(Element child)
      Method called when an element was added to the bin.
      Parameters:
      child - the element that was added

    • elementRemoved

      protected void elementRemoved(Element child)
      Method called when an element was removed from the bin.
      Parameters:
      child - the element that was removed

    • handleMessage

      protected void handleMessage(Message message)
      Method to handle a message from the children.
      Parameters:
      message - the message to be handled

    • removeElement

      protected boolean removeElement(Element element)
      Method to remove an element from the bin.
      Parameters:
      element - the element to be removed
      Returns:
      true if the element was removed

    • onDeepElementAdded

      public SignalConnection<Bin.DeepElementAddedCallback> onDeepElementAdded(Bin.DeepElementAddedCallback handler)
      Will be emitted after the element was added to subBin.
      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      Since:
      1.10
      See Also:

    • emitDeepElementAdded

      public void emitDeepElementAdded(@Nullable Bin subBin, @Nullable Element element)
      Emits the "deep-element-added" signal. See onDeepElementAdded(Bin.DeepElementAddedCallback).

    • onDeepElementRemoved

      public SignalConnection<Bin.DeepElementRemovedCallback> onDeepElementRemoved(Bin.DeepElementRemovedCallback handler)
      Will be emitted after the element was removed from subBin.
      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      Since:
      1.10
      See Also:

    • emitDeepElementRemoved

      public void emitDeepElementRemoved(@Nullable Bin subBin, @Nullable Element element)
      Emits the "deep-element-removed" signal. See onDeepElementRemoved(Bin.DeepElementRemovedCallback).

    • onDoLatency

      public SignalConnection<Bin.DoLatencyCallback> onDoLatency(Bin.DoLatencyCallback handler)

      Will be emitted when the bin needs to perform latency calculations. This signal is only emitted for toplevel bins or when GstBin: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.

      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitDoLatency

      public boolean emitDoLatency()
      Emits the "do-latency" signal. See onDoLatency(Bin.DoLatencyCallback).

    • onElementAdded

      public SignalConnection<Bin.ElementAddedCallback> onElementAdded(Bin.ElementAddedCallback handler)
      Will be emitted after the element was added to the bin.
      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitElementAdded

      public void emitElementAdded(@Nullable Element element)
      Emits the "element-added" signal. See onElementAdded(Bin.ElementAddedCallback).

    • onElementRemoved

      public SignalConnection<Bin.ElementRemovedCallback> onElementRemoved(Bin.ElementRemovedCallback handler)
      Will be emitted after the element was removed from the bin.
      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitElementRemoved

      public void emitElementRemoved(@Nullable Element element)
      Emits the "element-removed" signal. See onElementRemoved(Bin.ElementRemovedCallback).

    • builder

      public static Bin.Builder<? extends Bin.Builder> builder()
      A Bin.Builder object constructs a Bin with the specified properties. Use the various set...() methods to set properties, and finish construction with Bin.Builder.build().
      Returns:
      the builder object