GI.Gst.Objects.Bin

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 binNew. 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 binAdd. You can remove elements with binRemove.

An element can be retrieved from a bin with binGetByName, using the elements name. binGetByNameRecurseUp 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 binIterateElements. Various other iterators exist to retrieve the elements in a bin.

objectUnref is used to drop your reference to the bin.

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

Notes

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

• 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 Bin will by default forward any event sent to it to all sink (GST_EVENT_TYPE_DOWNSTREAM) or source (GST_EVENT_TYPE_UPSTREAM) 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.

Exported types

newtype Bin

Constructors

Bin (ManagedPtr Bin)

Instances

GObject Bin

Methods

gobjectType :: Bin -> IO GType

IsObject Bin

IsObject Bin

IsElement Bin

IsBin Bin

IsChildProxy Bin

class GObject o => IsBin o

Instances

(GObject a, UnknownAncestorError Constraint Bin a) => IsBin a

IsBin Bin

IsBin Pipeline

toBin :: (MonadIO m, IsBin o) => o -> m Bin

noBin :: Maybe Bin

Methods

add

binAdd

Arguments

:: (HasCallStack, MonadIO m, IsBin a, IsElement b)

=> a

bin: a Bin

-> b

element: the Element to add

-> m Bool

Returns: True if the element could be added, False if the bin does not want to accept the 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 'GI.Gst.Objects.Element.elementSetState', or use 'GI.Gst.Objects.Element.elementSyncStateWithParent'.
The bin or pipeline will not take care of this for you.

MT safe.

findUnlinkedPad

binFindUnlinkedPad

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: bin in which to look for elements with unlinked pads

-> PadDirection

direction: whether to look for an unlinked source or sink pad

-> m (Maybe Pad)

Returns: unlinked pad of the given direction, Nothing.

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 Nothing otherwise. If a pad is found, the caller owns a reference to it and should use objectUnref on the pad when it is not needed any longer.

getByInterface

binGetByInterface

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> GType

iface: the GType of an interface

-> m Element

Returns: A Element inside the bin implementing the interface

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 binIterateAllByInterface. This function recurses into child bins.

MT safe. Caller owns returned reference.

getByName

binGetByName

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> Text

name: the element name to search for

-> m (Maybe Element)

Returns: the Element with the given name, or Nothing

Gets the element with the given name from a bin. This function recurses into child bins.

Returns Nothing if no element with the given name is found in the bin.

MT safe. Caller owns returned reference.

getByNameRecurseUp

binGetByNameRecurseUp

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> Text

name: the element name to search for

-> m (Maybe Element)

Returns: the Element with the given name, or Nothing

Gets the element with the given name from this bin. If the element is not found, a recursion is performed on the parent bin.

Returns Nothing if:

• no element with the given name is found in the bin

MT safe. Caller owns returned reference.

getSuppressedFlags

binGetSuppressedFlags

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> m [ElementFlags]

Returns: the bin's suppressed ElementFlags.

Return the suppressed flags of the bin.

MT safe.

Since: 1.10

iterateAllByInterface

binIterateAllByInterface

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> GType

iface: the GType of an interface

-> m (Maybe Iterator)

Returns: a Iterator of Element for all elements in the bin implementing the given interface, or Nothing

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 Element that should be unreffed after use.

MT safe. Caller owns returned value.

iterateElements

binIterateElements

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> m (Maybe Iterator)

Returns: a Iterator of Element, or Nothing

Gets an iterator for the elements in this bin.

MT safe. Caller owns returned value.

iterateRecurse

binIterateRecurse

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> m (Maybe Iterator)

Returns: a Iterator of Element, or Nothing

Gets an iterator for the elements in this bin. This iterator recurses into GstBin children.

MT safe. Caller owns returned value.

iterateSinks

binIterateSinks

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> m (Maybe Iterator)

Returns: a Iterator of Element, or Nothing

Gets an iterator for all elements in the bin that have the GST_ELEMENT_FLAG_SINK flag set.

MT safe. Caller owns returned value.

iterateSorted

binIterateSorted

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> m (Maybe Iterator)

Returns: a Iterator of Element, or Nothing

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.

MT safe. Caller owns returned value.

iterateSources

binIterateSources

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> m (Maybe Iterator)

Returns: a Iterator of Element, or Nothing

Gets an iterator for all elements in the bin that have the GST_ELEMENT_FLAG_SOURCE flag set.

MT safe. Caller owns returned value.

new

binNew

Arguments

:: (HasCallStack, MonadIO m)

=> Maybe Text

name: the name of the new bin

-> m Bin

Returns: a new Bin

Creates a new bin with the given name.

recalculateLatency

binRecalculateLatency

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> m Bool

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

Query bin for the current latency using and reconfigures this latency to all the elements with 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 'do-latency' signal so any custom latency calculations will be performed.

remove

binRemove

Arguments

:: (HasCallStack, MonadIO m, IsBin a, IsElement b)

=> a

bin: a Bin

-> b

element: the Element to remove

-> m Bool

Returns: True if the element could be removed, False if the bin does not want to remove the 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 objectRef 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.

setSuppressedFlags

binSetSuppressedFlags

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> [ElementFlags]

flags: the ElementFlags to suppress

-> m ()

Suppress the given flags on the bin. ElementFlags 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.

MT safe.

Since: 1.10

syncChildrenStates

binSyncChildrenStates

Arguments

:: (HasCallStack, MonadIO m, IsBin a)

=> a

bin: a Bin

-> m Bool

Returns: True if syncing the state was successful for all children, otherwise False.

Synchronizes the state of every child of bin with the state of bin. See also elementSyncStateWithParent.

Since: 1.6

Properties

asyncHandling

constructBinAsyncHandling :: IsBin o => Bool -> IO (GValueConstruct o)

getBinAsyncHandling :: (MonadIO m, IsBin o) => o -> m Bool

setBinAsyncHandling :: (MonadIO m, IsBin o) => o -> Bool -> m ()

messageForward

constructBinMessageForward :: IsBin o => Bool -> IO (GValueConstruct o)

getBinMessageForward :: (MonadIO m, IsBin o) => o -> m Bool

setBinMessageForward :: (MonadIO m, IsBin o) => o -> Bool -> m ()

Signals

deepElementAdded

type BinDeepElementAddedCallback = Bin -> Element -> IO ()

type C_BinDeepElementAddedCallback = Ptr () -> Ptr Bin -> Ptr Element -> Ptr () -> IO ()

afterBinDeepElementAdded :: (IsBin a, MonadIO m) => a -> BinDeepElementAddedCallback -> m SignalHandlerId

genClosure_BinDeepElementAdded :: BinDeepElementAddedCallback -> IO Closure

mk_BinDeepElementAddedCallback :: C_BinDeepElementAddedCallback -> IO (FunPtr C_BinDeepElementAddedCallback)

noBinDeepElementAddedCallback :: Maybe BinDeepElementAddedCallback

onBinDeepElementAdded :: (IsBin a, MonadIO m) => a -> BinDeepElementAddedCallback -> m SignalHandlerId

wrap_BinDeepElementAddedCallback :: BinDeepElementAddedCallback -> Ptr () -> Ptr Bin -> Ptr Element -> Ptr () -> IO ()

deepElementRemoved

type BinDeepElementRemovedCallback = Bin -> Element -> IO ()

type C_BinDeepElementRemovedCallback = Ptr () -> Ptr Bin -> Ptr Element -> Ptr () -> IO ()

afterBinDeepElementRemoved :: (IsBin a, MonadIO m) => a -> BinDeepElementRemovedCallback -> m SignalHandlerId

genClosure_BinDeepElementRemoved :: BinDeepElementRemovedCallback -> IO Closure

mk_BinDeepElementRemovedCallback :: C_BinDeepElementRemovedCallback -> IO (FunPtr C_BinDeepElementRemovedCallback)

noBinDeepElementRemovedCallback :: Maybe BinDeepElementRemovedCallback

onBinDeepElementRemoved :: (IsBin a, MonadIO m) => a -> BinDeepElementRemovedCallback -> m SignalHandlerId

wrap_BinDeepElementRemovedCallback :: BinDeepElementRemovedCallback -> Ptr () -> Ptr Bin -> Ptr Element -> Ptr () -> IO ()

doLatency

type BinDoLatencyCallback = IO Bool

type C_BinDoLatencyCallback = Ptr () -> Ptr () -> IO CInt

afterBinDoLatency :: (IsBin a, MonadIO m) => a -> BinDoLatencyCallback -> m SignalHandlerId

genClosure_BinDoLatency :: BinDoLatencyCallback -> IO Closure

mk_BinDoLatencyCallback :: C_BinDoLatencyCallback -> IO (FunPtr C_BinDoLatencyCallback)

noBinDoLatencyCallback :: Maybe BinDoLatencyCallback

onBinDoLatency :: (IsBin a, MonadIO m) => a -> BinDoLatencyCallback -> m SignalHandlerId

wrap_BinDoLatencyCallback :: BinDoLatencyCallback -> Ptr () -> Ptr () -> IO CInt

elementAdded

type BinElementAddedCallback = Element -> IO ()

type C_BinElementAddedCallback = Ptr () -> Ptr Element -> Ptr () -> IO ()

afterBinElementAdded :: (IsBin a, MonadIO m) => a -> BinElementAddedCallback -> m SignalHandlerId

genClosure_BinElementAdded :: BinElementAddedCallback -> IO Closure

mk_BinElementAddedCallback :: C_BinElementAddedCallback -> IO (FunPtr C_BinElementAddedCallback)

noBinElementAddedCallback :: Maybe BinElementAddedCallback

onBinElementAdded :: (IsBin a, MonadIO m) => a -> BinElementAddedCallback -> m SignalHandlerId

wrap_BinElementAddedCallback :: BinElementAddedCallback -> Ptr () -> Ptr Element -> Ptr () -> IO ()

elementRemoved

type BinElementRemovedCallback = Element -> IO ()

type C_BinElementRemovedCallback = Ptr () -> Ptr Element -> Ptr () -> IO ()

afterBinElementRemoved :: (IsBin a, MonadIO m) => a -> BinElementRemovedCallback -> m SignalHandlerId

genClosure_BinElementRemoved :: BinElementRemovedCallback -> IO Closure

mk_BinElementRemovedCallback :: C_BinElementRemovedCallback -> IO (FunPtr C_BinElementRemovedCallback)

noBinElementRemovedCallback :: Maybe BinElementRemovedCallback

onBinElementRemoved :: (IsBin a, MonadIO m) => a -> BinElementRemovedCallback -> m SignalHandlerId

wrap_BinElementRemovedCallback :: BinElementRemovedCallback -> Ptr () -> Ptr Element -> Ptr () -> IO ()