Bin

#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.

<refsect2><title>Notes</title> <para> A #GstBin internally intercepts every #GstMessage posted by its children and implements the following default behaviour for each of them: <variablelist> <varlistentry> <term>GST_MESSAGE_EOS</term> <listitem><para>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.</para></listitem> </varlistentry> <varlistentry> <term>GST_MESSAGE_SEGMENT_START</term> <listitem><para>just collected and never forwarded upwards. The messages are used to decide when all elements have completed playback of their segment.</para></listitem> </varlistentry> <varlistentry> <term>GST_MESSAGE_SEGMENT_DONE</term> <listitem><para> Is posted by #GstBin when all elements that posted a SEGMENT_START have posted a SEGMENT_DONE.</para></listitem> </varlistentry> <varlistentry> <term>GST_MESSAGE_DURATION_CHANGED</term> <listitem><para> Is posted by an element that detected a change in the stream duration. The default bin behaviour is to clear any cached duration values so that the next duration query will perform a full duration recalculation. 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. </para></listitem> </varlistentry> <varlistentry> <term>GST_MESSAGE_CLOCK_LOST</term> <listitem><para> 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. </para></listitem> </varlistentry> <varlistentry> <term>GST_MESSAGE_CLOCK_PROVIDE</term> <listitem><para> 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 tot the application but is forwarded to the parent of the bin. </para></listitem> </varlistentry> <varlistentry> <term>OTHERS</term> <listitem><para> posted upwards.</para></listitem> </varlistentry> </variablelist>

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class Bin : Element , ChildProxyIF {

protected

GstBin* gstBin;

GstBin* getBinStruct();

void* getStruct();

void setStruct(GObject* obj);

this(GstBin* gstBin, bool ownedRef);

mixin ChildProxyT!(GstBin) ;

this(Element elem);

static GType getType();

this(string name);

bool add(Element element);

Pad findUnlinkedPad(GstPadDirection direction);

Element getByInterface(GType iface);

Element getByName(string name);

Element getByNameRecurseUp(string name);

Iterator iterateAllByInterface(GType iface);

Iterator iterateElements();

Iterator iterateRecurse();

Iterator iterateSinks();

Iterator iterateSorted();

Iterator iterateSources();

bool recalculateLatency();

bool remove(Element element);

int[string] connectedSignals;

bool delegate(Bin)[] onDoLatencyListeners;

void addOnDoLatency(bool delegate(Bin) dlg, ConnectFlags connectFlags);

static int callBackDoLatency(GstBin* binStruct, Bin _bin);

void delegate(Element, Bin)[] onElementAddedListeners;

void addOnElementAdded(void delegate(Element, Bin) dlg, ConnectFlags connectFlags);

static void callBackElementAdded(GstBin* binStruct, GstElement* element, Bin _bin);

void delegate(Element, Bin)[] onElementRemovedListeners;

void addOnElementRemoved(void delegate(Element, Bin) dlg, ConnectFlags connectFlags);

static void callBackElementRemoved(GstBin* binStruct, GstElement* element, Bin _bin);

}

Constructors

this this(GstBin* gstBin, bool ownedRef): Sets our main struct and passes it to the parent class.
this this(Element elem)
this this(string name): Creates a new bin with the given name.

Members

Functions

add bool 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.
addOnDoLatency void addOnDoLatency(bool delegate(Bin) dlg, ConnectFlags connectFlags): 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.
addOnElementAdded void addOnElementAdded(void delegate(Element, Bin) dlg, ConnectFlags connectFlags): Will be emitted after the element was added to the bin.
addOnElementRemoved void addOnElementRemoved(void delegate(Element, Bin) dlg, ConnectFlags connectFlags): Will be emitted after the element was removed from the bin.
findUnlinkedPad Pad findUnlinkedPad(GstPadDirection 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.
getBinStruct GstBin* getBinStruct(): Get the main Gtk struct
getByInterface Element getByInterface(GType 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.
getByName Element getByName(string name): Gets the element with the given name from a bin. This function recurses into child bins.
getByNameRecurseUp 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.
getStruct void* getStruct(): the main Gtk struct as a void*
iterateAllByInterface Iterator iterateAllByInterface(GType 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 that should be unreffed after use.
iterateElements Iterator iterateElements(): Gets an iterator for the elements in this bin.
iterateRecurse Iterator iterateRecurse(): Gets an iterator for the elements in this bin. This iterator recurses into GstBin children.
iterateSinks Iterator iterateSinks(): Gets an iterator for all elements in the bin that have the #GST_ELEMENT_FLAG_SINK flag set.
iterateSorted 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.
iterateSources Iterator iterateSources(): Gets an iterator for all elements in the bin that have the #GST_ELEMENT_FLAG_SOURCE flag set.
recalculateLatency bool recalculateLatency(): Query @bin for the current latency using and reconfigures this latency to all the elements with a LATENCY event.
remove bool 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.
setStruct void setStruct(GObject* obj): Undocumented in source. Be warned that the author may not have intended to support it.

Mixins

__anonymous mixin ChildProxyT!(GstBin): Undocumented in source.

Static functions

callBackDoLatency int callBackDoLatency(GstBin* binStruct, Bin _bin): Undocumented in source. Be warned that the author may not have intended to support it.
callBackElementAdded void callBackElementAdded(GstBin* binStruct, GstElement* element, Bin _bin): Undocumented in source. Be warned that the author may not have intended to support it.
callBackElementRemoved void callBackElementRemoved(GstBin* binStruct, GstElement* element, Bin _bin): Undocumented in source. Be warned that the author may not have intended to support it.
getType GType getType()

Variables

connectedSignals int[string] connectedSignals;: Undocumented in source.
gstBin GstBin* gstBin;: the main Gtk struct
onDoLatencyListeners bool delegate(Bin)[] onDoLatencyListeners;: Undocumented in source.
onElementAddedListeners void delegate(Element, Bin)[] onElementAddedListeners;: Undocumented in source.
onElementRemovedListeners void delegate(Element, Bin)[] onElementRemovedListeners;: Undocumented in source.

Inherited Members

From Element

gstElement GstElement* gstElement;: the main Gtk struct
getElementStruct GstElement* getElementStruct(): Get the main Gtk struct
getStruct void* getStruct(): the main Gtk struct as a void*
setStruct void setStruct(GObject* obj): Undocumented in source. Be warned that the author may not have intended to support it.
queryPosition long queryPosition(): Queries an element for the stream position. This is a convenience function for gstreamerD.
queryDuration long queryDuration(): Queries an element for the stream duration. This is a convenience function for gstreamerD.
location void location(string set): This set's the filename for a filesrc element.
caps void caps(Caps cp): Set the caps property of an Element.
seek int seek(long time_nanoseconds): For your convenience in gstreamerD: you can seek to the position of the pipeline measured in time_nanoseconds.
pads Pad[] pads(): Get's all the pads from an element in a Pad[].
getType GType getType()
makeFromUri Element makeFromUri(GstURIType type, string uri, string elementname): Creates an element for handling the given URI.
register bool register(Plugin plugin, string name, uint rank, GType type): Create a new elementfactory capable of instantiating objects of the @type and add the factory to @plugin.
stateChangeReturnGetName string stateChangeReturnGetName(GstStateChangeReturn stateRet): Gets a string representing the given state change result.
stateGetName string stateGetName(GstState state): Gets a string representing the given state.
abortState void abortState(): Abort the state change of the element. This function is used by elements that do asynchronous state changes and find out something is wrong.
addPad bool addPad(Pad pad): Adds a pad (link point) to @element. @pad's parent will be set to @element; see gst_object_set_parent() for refcounting information.
changeState GstStateChangeReturn changeState(GstStateChange transition): Perform @transition on @element.
continueState GstStateChangeReturn continueState(GstStateChangeReturn ret): Commit the state change of the element and proceed to the next pending state if any. This function is used by elements that do asynchronous state changes. The core will normally call this method automatically when an element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
createAllPads void createAllPads(): Creates a pad for each pad template that is always available. This function is only useful during object initialization of subclasses of #GstElement.
getBaseTime GstClockTime getBaseTime(): Returns the base time of the element. The base time is the absolute time of the clock when this element was last put to PLAYING. Subtracting the base time from the clock time gives the running time of the element.
getBus Bus getBus(): Returns the bus of the element. Note that only a #GstPipeline will provide a bus for the application.
getClock Clock getClock(): Gets the currently configured clock of the element. This is the clock as was last set with gst_element_set_clock().
getCompatiblePad Pad getCompatiblePad(Pad pad, Caps caps): Looks for an unlinked pad to which the given pad can link. It is not guaranteed that linking the pads will work, though it should work in most cases.
getCompatiblePadTemplate PadTemplate getCompatiblePadTemplate(PadTemplate compattempl): Retrieves a pad template from @element that is compatible with @compattempl. Pads from compatible templates can be linked together.
getFactory ElementFactory getFactory(): Retrieves the factory that was used to create this element.
getRequestPad Pad getRequestPad(string name): Retrieves a pad from the element by name (e.g. "src_\%d"). This version only retrieves request pads. The pad should be released with gst_element_release_request_pad().
getStartTime GstClockTime getStartTime(): Returns the start time of the element. The start time is the running time of the clock when this element was last put to PAUSED.
getState GstStateChangeReturn getState(GstState state, GstState pending, GstClockTime timeout): Gets the state of the element.
getStaticPad Pad getStaticPad(string name): Retrieves a pad from @element by name. This version only retrieves already-existing (i.e. 'static') pads.
isLockedState bool isLockedState(): Checks if the state of an element is locked. If the state of an element is locked, state changes of the parent don't affect the element. This way you can leave currently unused elements inside bins. Just lock their state before changing the state from #GST_STATE_NULL.
iteratePads Iterator iteratePads(): Retrieves an iterator of @element's pads. The iterator should be freed after usage. Also more specialized iterators exists such as gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
iterateSinkPads Iterator iterateSinkPads(): Retrieves an iterator of @element's sink pads.
iterateSrcPads Iterator iterateSrcPads(): Retrieves an iterator of @element's source pads.
link bool link(Element dest): Links @src to @dest. The link must be from source to destination; the other direction will not be tried. The function looks for existing pads that aren't linked yet. It will request new pads if necessary. Such pads need to be released manually when unlinking. If multiple links are possible, only one is established.
linkFiltered bool linkFiltered(Element dest, Caps filter): Links @src to @dest using the given caps as filtercaps. The link must be from source to destination; the other direction will not be tried. The function looks for existing pads that aren't linked yet. It will request new pads if necessary. If multiple links are possible, only one is established.
linkPads bool linkPads(string srcpadname, Element dest, string destpadname): Links the two named pads of the source and destination elements. Side effect is that if one of the pads has no parent, it becomes a child of the parent of the other element. If they have different parents, the link fails.
linkPadsFiltered bool linkPadsFiltered(string srcpadname, Element dest, string destpadname, Caps filter): Links the two named pads of the source and destination elements. Side effect is that if one of the pads has no parent, it becomes a child of the parent of the other element. If they have different parents, the link fails. If @caps is not %NULL, makes sure that the caps of the link is a subset of @caps.
linkPadsFull bool linkPadsFull(string srcpadname, Element dest, string destpadname, GstPadLinkCheck flags): Links the two named pads of the source and destination elements. Side effect is that if one of the pads has no parent, it becomes a child of the parent of the other element. If they have different parents, the link fails.
lostState void lostState(): Brings the element to the lost state. The current state of the element is copied to the pending state so that any call to gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
messageFull void messageFull(GstMessageType type, GQuark domain, int code, string text, string dbg, string file, string funct, int line): Post an error, warning or info message on the bus from inside an element.
noMorePads void noMorePads(): Use this function to signal that the element does not expect any more pads to show up in the current pipeline. This function should be called whenever pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES pad templates use this in combination with autopluggers to figure out that the element is done initializing its pads.
postMessage bool postMessage(Message message): Post a message on the element's #GstBus. This function takes ownership of the message; if you want to access the message after this call, you should add an additional reference before calling.
provideClock Clock provideClock(): Get the clock provided by the given element. <note>An element is only required to provide a clock in the PAUSED state. Some elements can provide a clock in other states.</note>
query bool query(Query query): Performs a query on the given element.
queryConvert bool queryConvert(GstFormat srcFormat, long srcVal, GstFormat destFormat, long destVal): Queries an element to convert @src_val in @src_format to @dest_format.
queryDuration bool queryDuration(GstFormat format, long duration): Queries an element (usually top-level pipeline or playbin element) for the total stream duration in nanoseconds. This query will only work once the pipeline is prerolled (i.e. reached PAUSED or PLAYING state). The application will receive an ASYNC_DONE message on the pipeline bus when that is the case.
queryPosition bool queryPosition(GstFormat format, long cur): Queries an element (usually top-level pipeline or playbin element) for the stream position in nanoseconds. This will be a value between 0 and the stream duration (if the stream duration is known). This query will usually only work once the pipeline is prerolled (i.e. reached PAUSED or PLAYING state). The application will receive an ASYNC_DONE message on the pipeline bus when that is the case.
releaseRequestPad void releaseRequestPad(Pad pad): Makes the element free the previously requested pad as obtained with gst_element_request_pad().
removePad bool removePad(Pad pad): Removes @pad from @element. @pad will be destroyed if it has not been referenced elsewhere using gst_object_unparent().
requestPad Pad requestPad(PadTemplate templ, string name, Caps caps): Retrieves a request pad from the element according to the provided template. Pad templates can be looked up using gst_element_factory_get_static_pad_templates().
seek bool seek(double rate, GstFormat format, GstSeekFlags flags, GstSeekType startType, long start, GstSeekType stopType, long stop): Sends a seek event to an element. See gst_event_new_seek() for the details of the parameters. The seek event is sent to the element using gst_element_send_event().
seekSimple bool seekSimple(GstFormat format, GstSeekFlags seekFlags, long seekPos): Simple API to perform a seek on the given element, meaning it just seeks to the given position relative to the start of the stream. For more complex operations like segment seeks (e.g. for looping) or changing the playback rate or seeking relative to the last configured playback segment you should use gst_element_seek().
sendEvent bool sendEvent(Event event): Sends an event to an element. If the element doesn't implement an event handler, the event will be pushed on a random linked sink pad for downstream events or a random linked source pad for upstream events.
setBaseTime void setBaseTime(GstClockTime time): Set the base time of an element. See gst_element_get_base_time().
setBus void setBus(Bus bus): Sets the bus of the element. Increases the refcount on the bus. For internal use only, unless you're testing elements.
setClock bool setClock(Clock clock): Sets the clock for the element. This function increases the refcount on the clock. Any previously set clock on the object is unreffed.
setContext void setContext(Context context): Sets the context of the element. Increases the refcount of the context.
setLockedState bool setLockedState(bool lockedState): Locks the state of an element, so state changes of the parent don't affect this element anymore.
setStartTime void setStartTime(GstClockTime time): Set the start time of an element. The start time of the element is the running time of the element when it last went to the PAUSED state. In READY or after a flushing seek, it is set to 0.
setState GstStateChangeReturn setState(GstState state): Sets the state of the element. This function will try to set the requested state by going through all the intermediary states and calling the class's state change function for each.
syncStateWithParent bool syncStateWithParent(): Tries to change the state of the element to the same as its parent. If this function returns %FALSE, the state of element is undefined.
unlink void unlink(Element dest): Unlinks all source pads of the source element with all sink pads of the sink element to which they are linked.
unlinkPads void unlinkPads(string srcpadname, Element dest, string destpadname): Unlinks the two named pads of the source and destination elements.
connectedSignals int[string] connectedSignals;: Undocumented in source.
onNoMorePadsListeners void delegate(Element)[] onNoMorePadsListeners;: Undocumented in source.
addOnNoMorePads void addOnNoMorePads(void delegate(Element) dlg, ConnectFlags connectFlags): 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.
callBackNoMorePads void callBackNoMorePads(GstElement* elementStruct, Element _element): Undocumented in source. Be warned that the author may not have intended to support it.
onPadAddedListeners void delegate(Pad, Element)[] onPadAddedListeners;: Undocumented in source.
addOnPadAdded void addOnPadAdded(void delegate(Pad, Element) dlg, ConnectFlags connectFlags): a new #GstPad 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 gst_element_set_state() or gst_element_sync_state_with_parent().
callBackPadAdded void callBackPadAdded(GstElement* elementStruct, GstPad* newPad, Element _element): Undocumented in source. Be warned that the author may not have intended to support it.
onPadRemovedListeners void delegate(Pad, Element)[] onPadRemovedListeners;: Undocumented in source.
addOnPadRemoved void addOnPadRemoved(void delegate(Pad, Element) dlg, ConnectFlags connectFlags): a #GstPad has been removed from the element
callBackPadRemoved void callBackPadRemoved(GstElement* elementStruct, GstPad* oldPad, Element _element): Undocumented in source. Be warned that the author may not have intended to support it.

From ChildProxyIF

getChildProxyStruct GstChildProxy* getChildProxyStruct(): Get the main Gtk struct
getStruct void* getStruct(): the main Gtk struct as a void*
childAdded void childAdded(ObjectG child, string name): Emits the "child-added" signal.
childRemoved void childRemoved(ObjectG child, string name): Emits the "child-removed" signal.
getChildByIndex ObjectG getChildByIndex(uint index): Fetches a child by its number.
getChildByName ObjectG getChildByName(string name): Looks up a child element by the given name.
getChildrenCount uint getChildrenCount(): Gets the number of child objects this parent contains.
childGetProperty void childGetProperty(string name, Value value): Gets a single property using the GstChildProxy mechanism. You are responsible for freeing it by calling g_value_unset()
childGetValist void childGetValist(string firstPropertyName, void* varArgs): Gets properties of the parent object and its children.
lookup bool lookup(string name, ObjectG target, ParamSpec pspec): Looks up which object and #GParamSpec would be effected by the given @name.
childSetProperty void childSetProperty(string name, Value value): Sets a single property using the GstChildProxy mechanism.
childSetValist void childSetValist(string firstPropertyName, void* varArgs): Sets properties of the parent object and its children.
onChildAddedListeners void delegate(ObjectG, string, ChildProxyIF)[] onChildAddedListeners [@property getter]: Undocumented in source.
addOnChildAdded void addOnChildAdded(void delegate(ObjectG, string, ChildProxyIF) dlg, ConnectFlags connectFlags): Will be emitted after the @object was added to the @child_proxy.
onChildRemovedListeners void delegate(ObjectG, string, ChildProxyIF)[] onChildRemovedListeners [@property getter]: Undocumented in source.
addOnChildRemoved void addOnChildRemoved(void delegate(ObjectG, string, ChildProxyIF) dlg, ConnectFlags connectFlags): Will be emitted after the @object was removed from the @child_proxy.

Detailed Description

A #GstBin implements the following default behaviour for answering to a #GstQuery: <variablelist> <varlistentry> <term>GST_QUERY_DURATION</term> <listitem><para>If the query has been asked before with the same format and the bin is a toplevel bin (ie. has no parent), use the cached previous value. If no previous value was cached, the query is sent to all sink elements in the bin and the MAXIMUM of all values is returned. If the bin is a toplevel bin the value is cached. If no sinks are available in the bin, the query fails. </para></listitem> </varlistentry> <varlistentry> <term>GST_QUERY_POSITION</term> <listitem><para>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. </para></listitem> </varlistentry> <varlistentry> <term>OTHERS</term> <listitem><para>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.</para></listitem> </varlistentry> </variablelist>

A #GstBin will by default forward any event sent to it to all sink elements. If all the sinks return %TRUE, the bin will also return %TRUE, else %FALSE is returned. If no sinks are in the bin, the event handler will return %TRUE.

</para> </refsect2>