Bin

Description 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 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. Notes A GstBin internally intercepts every GstMessage 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 GstBin when all elements that posted a SEGMENT_START have posted a SEGMENT_DONE. GST_MESSAGE_DURATION 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. 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 tot 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: GST_QUERY_DURATION 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. 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 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. Last reviewed on 2006-04-28 (0.10.6)

Constructors

this
this(GstBin* gstBin)

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
int 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. MT safe.

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.

findUnconnectedPad
Pad findUnconnectedPad(GstPadDirection direction)

Recursively looks for elements with an unconnected pad of the given direction within the specified bin and returns an unconnected 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()
Undocumented in source. Be warned that the author may not have intended to support it.
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. MT safe. Caller owns returned reference.

getByName
Element getByName(string name)

Gets the element with the given name from a bin. This function recurses into child bins. Returns NULL if no element with the given name is found in the bin. MT safe. Caller owns returned reference.

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. Each element yielded by the iterator will have its refcount increased, so unref after use. MT safe. Caller owns returned value.

iterateElements
Iterator iterateElements()

Gets an iterator for the elements in this bin. Each element yielded by the iterator will have its refcount increased, so unref after use. MT safe. Caller owns returned value.

iterateRecurse
Iterator iterateRecurse()

Gets an iterator for the elements in this bin. This iterator recurses into GstBin children. Each element yielded by the iterator will have its refcount increased, so unref after use. MT safe. Caller owns returned value.

iterateSinks
Iterator iterateSinks()

Gets an iterator for all elements in the bin that have the GST_ELEMENT_IS_SINK flag set. Each element yielded by the iterator will have its refcount increased, so unref after use. MT safe. Caller owns returned value.

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. This function is used internally to perform the state changes of the bin elements. Each element yielded by the iterator will have its refcount increased, so unref after use. MT safe. Caller owns returned value.

iterateSources
Iterator iterateSources()

Gets an iterator for all elements in the bin that have no sinkpads and have the GST_ELEMENT_IS_SINK flag unset. Each element yielded by the iterator will have its refcount increased, so unref after use. MT safe. Caller owns returned value.

remove
int 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. MT safe.

setStruct
void setStruct(GObject* obj)
Undocumented in source. Be warned that the author may not have intended to support it.

Static functions

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.

Variables

connectedSignals
int[string] connectedSignals;
gstBin
GstBin* gstBin;

the main Gtk struct

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()
Undocumented in source. Be warned that the author may not have intended to support it.
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[]. FIXME: This a hackish mess.

connectedSignals
int[string] connectedSignals;
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.

callBackNoMorePads
void callBackNoMorePads(GstElement* gstelementStruct, 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.

callBackPadAdded
void callBackPadAdded(GstElement* gstelementStruct, 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 See Also GstElementFactory, GstPad

callBackPadRemoved
void callBackPadRemoved(GstElement* gstelementStruct, GstPad* oldPad, Element _element)
Undocumented in source. Be warned that the author may not have intended to support it.
classAddPadTemplate
void classAddPadTemplate(GstElementClass* klass, PadTemplate templ)

Adds a padtemplate to an element class. This is mainly used in the _base_init functions of classes.

classGetPadTemplate
PadTemplate classGetPadTemplate(GstElementClass* elementClass, string name)

Retrieves a padtemplate from element_class with the given name. Note If you use this function in the GInstanceInitFunc of an object class that has subclasses, make sure to pass the g_class parameter of the GInstanceInitFunc here.

classGetPadTemplateList
GList* classGetPadTemplateList(GstElementClass* elementClass)

Retrieves a list of the pad templates associated with element_class. The list must not be modified by the calling code. Note If you use this function in the GInstanceInitFunc of an object class that has subclasses, make sure to pass the g_class parameter of the GInstanceInitFunc here.

classSetDetails
void classSetDetails(GstElementClass* klass, GstElementDetails* details)

Sets the detailed information for a GstElementClass. Note This function is for use in _base_init functions only. The details are copied.

classSetDetailsSimple
void classSetDetailsSimple(GstElementClass* klass, string longname, string classification, string description, string author)

Sets the detailed information for a GstElementClass. Simpler version of gst_element_class_set_details() that generates less linker overhead. Note This function is for use in _base_init functions only. The detail parameter strings are copied into the GstElementDetails for the element class.

addPad
int 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. Pads are not automatically activated so elements should perform the needed steps to activate the pad in case this pad is added in the PAUSED or PLAYING state. See gst_pad_set_active() for more information about activating pads. The pad and the element should be unlocked when calling this function. This function will emit the GstElement::pad-added signal on the element.

getPad
Pad getPad(string name)

Retrieves a pad from element by name. Tries gst_element_get_static_pad() first, then gst_element_get_request_pad(). Note Usage of this function is not recommended as it is unclear if the reference to the result pad should be released with gst_object_unref() in case of a static pad or gst_element_release_request_pad() in case of a request pad.

createAllPads
void createAllPads()

Creates a pad for each pad template that is always available. This function is only useful during object intialization of subclasses of GstElement.

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.

getRequestPad
Pad getRequestPad(string name)

Retrieves a pad from the element by name. This version only retrieves request pads. The pad should be released with gst_element_release_request_pad().

getStaticPad
Pad getStaticPad(string name)

Retrieves a pad from element by name. This version only retrieves already-existing (i.e. 'static') pads.

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. This function emits the GstElement::no-more-pads signal. MT safe.

releaseRequestPad
void releaseRequestPad(Pad pad)

Makes the element free the previously requested pad as obtained with gst_element_get_request_pad(). MT safe.

removePad
int removePad(Pad pad)

Removes pad from element. pad will be destroyed if it has not been referenced elsewhere using gst_object_unparent(). This function is used by plugin developers and should not be used by applications. Pads that were dynamically requested from elements with gst_element_get_request_pad() should be released with the gst_element_release_request_pad() function instead. Pads are not automatically deactivated so elements should perform the needed steps to deactivate the pad in case this pad is removed in the PAUSED or PLAYING state. See gst_pad_set_active() for more information about deactivating pads. The pad and the element should be unlocked when calling this function. This function will emit the GstElement::pad-removed signal on the element.

iteratePads
Iterator iteratePads()

Retrieves an iterattor of element's pads. The iterator should be freed after usage.

iterateSinkPads
Iterator iterateSinkPads()

Retrieves an iterator of element's sink pads.

iterateSrcPads
Iterator iterateSrcPads()

Retrieves an iterator of element's source pads.

link
int 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 manualy when unlinking. If multiple links are possible, only one is established. Make sure you have added your elements to a bin or pipeline with gst_bin_add() before trying to link them.

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. If the link has been made using gst_element_link(), it could have created an requestpad, which has to be released using gst_element_release_request_pad().

linkPads
int 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.

unlinkPads
void unlinkPads(string srcpadname, Element dest, string destpadname)

Unlinks the two named pads of the source and destination elements.

linkPadsFiltered
int 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.

linkFiltered
int 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. Make sure you have added your elements to a bin or pipeline with gst_bin_add() before trying to link them.

setBaseTime
void setBaseTime(GstClockTime time)

Set the base time of an element. See gst_element_get_base_time(). MT safe.

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 stream time of the element.

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. MT safe.

getBus
Bus getBus()

Returns the bus of the element. Note that only a GstPipeline will provide a bus for the application.

getFactory
ElementFactory getFactory()

Retrieves the factory that was used to create this element.

setIndex
void setIndex(Index index)

Set index on the element. The refcount of the index will be increased, any previously set index is unreffed. MT safe.

getIndex
Index getIndex()

Gets the index from the element.

isIndexable
int isIndexable()

Queries if the element can be indexed.

requiresClock
int requiresClock()

Query if the element requires a clock.

setClock
int 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.

getClock
Clock getClock()

Gets the currently configured clock of the element. This is the clock as was last set with gst_element_set_clock().

providesClock
int providesClock()

Query if the element provides a clock. A GstClock provided by an element can be used as the global GstClock for the pipeline. An element that can provide a clock is only required to do so in the PAUSED state, this means when it is fully negotiated and has allocated the resources to operate the clock.

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.

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. This function can return GST_STATE_CHANGE_ASYNC, in which case the element will perform the remainder of the state change asynchronously in another thread. An application can use gst_element_get_state() to wait for the completion of the state change or it can wait for a state change message on the bus.

getState
GstStateChangeReturn getState(GstState state, GstState pending, GstClockTime timeout)

Gets the state of the element. For elements that performed an ASYNC state change, as reported by gst_element_set_state(), this function will block up to the specified timeout value for the state change to complete. If the element completes the state change or goes into an error, this function returns immediately with a return value of GST_STATE_CHANGE_SUCCESS or GST_STATE_CHANGE_FAILURE respectively. For elements that did not return GST_STATE_CHANGE_ASYNC, this function returns the current and pending state immediately. This function returns GST_STATE_CHANGE_NO_PREROLL if the element successfully changed its state but is not able to provide data yet. This mostly happens for live sources that only produce data in the PLAYING state. While the state change return is equivalent to GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that some sink elements might not be able to complete their state change because an element is not producing data to complete the preroll. When setting the element to playing, the preroll will complete and playback will start.

setLockedState
int setLockedState(int lockedState)

Locks the state of an element, so state changes of the parent don't affect this element anymore. MT safe.

isLockedState
int 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. MT safe.

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. This function should be called with the STATE_LOCK held. MT safe.

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. If after calling this method the element still has not reached the pending state, the next state change is performed. This method is used internally and should normally not be called by plugins or applications.

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. An ASYNC_START message is posted with an indication to distribute a new base_time to the element. If the element was PLAYING, it will go to PAUSED. The element will be restored to its PLAYING state by the parent pipeline when it prerolls again. This is mostly used for elements that lost their preroll buffer in the GST_STATE_PAUSED or GST_STATE_PLAYING state after a flush, they will go to their pending state again when a new preroll buffer is queued. This function can only be called when the element is currently not in error or an async state change. This function is used internally and should normally not be called from plugins or applications. MT safe.

stateGetName
string stateGetName(GstState state)

Gets a string representing the given state.

stateChangeReturnGetName
string stateChangeReturnGetName(GstStateChangeReturn stateRet)

Gets a string representing the given state change result.

syncStateWithParent
int 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.

changeState
GstStateChangeReturn changeState(GstStateChange transition)

Perform transition on element. This function must be called with STATE_LOCK held and is mainly used internally.

foundTags
void foundTags(TagList list)

Posts a message to the bus that new tags were found, and pushes an event to all sourcepads. Takes ownership of the list. This is a utility method for elements. Applications should use the GstTagSetter interface.

foundTagsForPad
void foundTagsForPad(Pad pad, TagList list)

Posts a message to the bus that new tags were found and pushes the tags as event. Takes ownership of the list. This is a utility method for elements. Applications should use the GstTagSetter interface.

messageFull
void messageFull(GstMessageType type, GQuark domain, int code, string text, string dbug, string file, string funct, int line)

Post an error, warning or info message on the bus from inside an element. type must be of GST_MESSAGE_ERROR, GST_MESSAGE_WARNING or GST_MESSAGE_INFO. MT safe.

postMessage
int 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.

getQueryTypes
GstQueryType* getQueryTypes()

Get an array of query types from the element. If the element doesn't implement a query types function, the query will be forwarded to the peer of a random linked sink pad.

query
int query(Query query)

Performs a query on the given element. For elements that don't implement a query handler, this function forwards the query to a random srcpad or to the peer of a random linked sinkpad of this element.

queryConvert
int queryConvert(GstFormat srcFormat, long srcVal, GstFormat destFormat, long* destVal)

Queries an element to convert src_val in src_format to dest_format.

queryPosition
int queryPosition(GstFormat format, long cur)

Queries an element for the stream position.

queryDuration
int queryDuration(GstFormat format, long duration)

Queries an element for the total stream duration.

sendEvent
int 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 upstream events or a random linked source pad for downstream events. This function takes owership of the provided event so you should gst_event_ref() it if you want to reuse the event after this call.

seekSimple
int 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(). In a completely prerolled PAUSED or PLAYING pipeline, seeking is always guaranteed to return TRUE on a seekable media type or FALSE when the media type is certainly not seekable (such as a live stream). Some elements allow for seeking in the READY state, in this case they will store the seek event and execute it when they are put to PAUSED. If the element supports seek in READY, it will always return TRUE when it receives the event in the READY state.

seek
int seek(double rate, GstFormat format, GstSeekFlags flags, GstSeekType curType, long cur, 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().

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