GstDataQueue

GstDataQueue is an object that handles threadsafe queueing of objects. It also provides size-related functionality. This object should be used for any GstElement that wishes to provide some sort of queueing functionality.

GstDataQueue

GObject
    ╰──GstDataQueue

Opaque GstDataQueue structure.

Members

object (GObject) –

the parent structure

Class structure

GstDataQueueClass

Fields

parent_class (GObjectClass) –

No description available

_gst_reserved (gpointer *) –

No description available

GstBase.DataQueueClass

Attributes

parent_class (GObject.ObjectClass) –

No description available

_gst_reserved ([ Object ]) –

No description available

GstBase.DataQueueClass

Attributes

parent_class (GObject.ObjectClass) –

No description available

_gst_reserved ([ object ]) –

No description available

GstBase.DataQueue

GObject.Object
    ╰──GstBase.DataQueue

Opaque GstBase.DataQueue structure.

Members

object (GObject.Object) –

the parent structure

GstBase.DataQueue

GObject.Object
    ╰──GstBase.DataQueue

Opaque GstBase.DataQueue structure.

Members

object (GObject.Object) –

the parent structure

Constructors

gst_data_queue_new

GstDataQueue *
gst_data_queue_new (GstDataQueueCheckFullFunction checkfull,
                    GstDataQueueFullCallback fullcallback,
                    GstDataQueueEmptyCallback emptycallback,
                    gpointer checkdata)

Creates a new GstDataQueue. If fullcallback or emptycallback are supplied, then the GstDataQueue will call the respective callback to signal full or empty condition. If the callbacks are NULL the GstDataQueue will instead emit 'full' and 'empty' signals.

Parameters:

checkfull –

the callback used to tell if the element considers the queue full or not.

fullcallback –

the callback which will be called when the queue is considered full.

emptycallback –

the callback which will be called when the queue is considered empty.

checkdata –

a gpointer that will be passed to the checkfull, fullcallback, and emptycallback callbacks.

Returns –

a new GstDataQueue.

Since : 1.2

Methods

gst_data_queue_drop_head

gboolean
gst_data_queue_drop_head (GstDataQueue * queue,
                          GType type)

Pop and unref the head-most GstMiniObject with the given GType.

Parameters:

queue –

The GstDataQueue to drop an item from.

type –

The GType of the item to drop.

Returns –

TRUE if an element was removed.

Since : 1.2

gst_data_queue_flush

gst_data_queue_flush (GstDataQueue * queue)

Flushes all the contents of the queue. Any call to gst_data_queue_push and gst_data_queue_pop will be released. MT safe.

Parameters:

queue –

a GstDataQueue.

Since : 1.2

gst_data_queue_get_level

gst_data_queue_get_level (GstDataQueue * queue,
                          GstDataQueueSize * level)

Get the current level of the queue.

Parameters:

queue –

The GstDataQueue

level ( [out]) –

the location to store the result

Since : 1.2

gst_data_queue_is_empty

gboolean
gst_data_queue_is_empty (GstDataQueue * queue)

Queries if there are any items in the queue. MT safe.

Parameters:

queue –

a GstDataQueue.

Returns –

TRUE if queue is empty.

Since : 1.2

gst_data_queue_is_full

gboolean
gst_data_queue_is_full (GstDataQueue * queue)

Queries if queue is full. This check will be done using the GstDataQueueCheckFullFunction registered with queue. MT safe.

Parameters:

queue –

a GstDataQueue.

Returns –

TRUE if queue is full.

Since : 1.2

gst_data_queue_limits_changed

gst_data_queue_limits_changed (GstDataQueue * queue)

Inform the queue that the limits for the fullness check have changed and that any blocking gst_data_queue_push should be unblocked to recheck the limits.

Parameters:

queue –

The GstDataQueue

Since : 1.2

gst_data_queue_peek

gboolean
gst_data_queue_peek (GstDataQueue * queue,
                     GstDataQueueItem ** item)

Retrieves the first item available on the queue without removing it. If the queue is currently empty, the call will block until at least one item is available, OR the queue is set to the flushing state. MT safe.

Parameters:

queue –

a GstDataQueue.

item ( [out]) –

pointer to store the returned GstDataQueueItem.

Returns –

TRUE if an item was successfully retrieved from the queue.

Since : 1.2

gst_data_queue_pop

gboolean
gst_data_queue_pop (GstDataQueue * queue,
                    GstDataQueueItem ** item)

Retrieves the first item available on the queue. If the queue is currently empty, the call will block until at least one item is available, OR the queue is set to the flushing state. MT safe.

Parameters:

queue –

a GstDataQueue.

item ( [out]) –

pointer to store the returned GstDataQueueItem.

Returns –

TRUE if an item was successfully retrieved from the queue.

Since : 1.2

gst_data_queue_push

gboolean
gst_data_queue_push (GstDataQueue * queue,
                     GstDataQueueItem * item)

Pushes a GstDataQueueItem (or a structure that begins with the same fields) on the queue. If the queue is full, the call will block until space is available, OR the queue is set to flushing state. MT safe.

Note that this function has slightly different semantics than gst_pad_push and gst_pad_push_event: this function only takes ownership of item and the GstMiniObject contained in item if the push was successful. If FALSE is returned, the caller is responsible for freeing item and its contents.

Parameters:

queue –

a GstDataQueue.

item –

a GstDataQueueItem.

Returns –

TRUE if the item was successfully pushed on the queue.

Since : 1.2

gst_data_queue_push_force

gboolean
gst_data_queue_push_force (GstDataQueue * queue,
                           GstDataQueueItem * item)

Pushes a GstDataQueueItem (or a structure that begins with the same fields) on the queue. It ignores if the queue is full or not and forces the item to be pushed anyway. MT safe.

Parameters:

queue –

a GstDataQueue.

item –

a GstDataQueueItem.

Returns –

TRUE if the item was successfully pushed on the queue.

Since : 1.2

gst_data_queue_set_flushing

gst_data_queue_set_flushing (GstDataQueue * queue,
                             gboolean flushing)

Sets the queue to flushing state if flushing is TRUE. If set to flushing state, any incoming data on the queue will be discarded. Any call currently blocking on gst_data_queue_push or gst_data_queue_pop will return straight away with a return value of FALSE. While the queue is in flushing state, all calls to those two functions will return FALSE.

MT Safe.

Parameters:

queue –

a GstDataQueue.

flushing –

a gboolean stating if the queue will be flushing or not.

Since : 1.2

Signals

empty

empty_callback (GstDataQueue * self,
                gpointer user_data)

Reports that the queue became empty (empty). A queue is empty if the total amount of visible items inside it (num-visible, time, size) is lower than the boundary values which can be set through the GObject properties.

Parameters:

self –

No description available

user_data –

No description available

Flags: Run First

full

full_callback (GstDataQueue * self,
               gpointer user_data)

Reports that the queue became full (full). A queue is full if the total amount of data inside it (num-visible, time, size) is higher than the boundary values which can be set through the GObject properties.

Parameters:

self –

No description available

user_data –

No description available

Flags: Run First

Properties

current-level-bytes

“current-level-bytes” guint

Flags : Read

current-level-bytes

“current-level-bytes” Number

Flags : Read

current_level_bytes

“self.props.current_level_bytes” int

Flags : Read

current-level-time

“current-level-time” guint64

Flags : Read

current-level-time

“current-level-time” Number

Flags : Read

current_level_time

“self.props.current_level_time” int

Flags : Read

current-level-visible

“current-level-visible” guint

Flags : Read

current-level-visible

“current-level-visible” Number

Flags : Read

current_level_visible

“self.props.current_level_visible” int

Flags : Read

Virtual Methods

empty

empty (GstDataQueue * queue)

Parameters:

queue –

No description available

vfunc_empty

function vfunc_empty(queue: GstBase.DataQueue): {
    // javascript implementation of the 'empty' virtual method
}

Parameters:

queue (GstBase.DataQueue) –

No description available

do_empty

def do_empty (queue):
    #python implementation of the 'empty' virtual method

Parameters:

queue (GstBase.DataQueue) –

No description available

full

full (GstDataQueue * queue)

Parameters:

queue –

No description available

vfunc_full

function vfunc_full(queue: GstBase.DataQueue): {
    // javascript implementation of the 'full' virtual method
}

Parameters:

queue (GstBase.DataQueue) –

No description available

do_full

def do_full (queue):
    #python implementation of the 'full' virtual method

Parameters:

queue (GstBase.DataQueue) –

No description available

GstDataQueueItem

Structure used by GstDataQueue. You can supply a different structure, as long as the top of the structure is identical to this structure.

Members

object (GstMiniObject *) –

the GstMiniObject to queue.

size (guint) –

the size in bytes of the miniobject.

duration (guint64) –

the duration in GstClockTime of the miniobject. Can not be GST_CLOCK_TIME_NONE.

visible (gboolean) –

TRUE if object should be considered as a visible object.

destroy (GDestroyNotify) –

The GDestroyNotify function to use to free the GstDataQueueItem. This function should also drop the reference to object the owner of the GstDataQueueItem is assumed to hold.

GstDataQueueSize

Structure describing the size of a queue.

Members

visible (guint) –

number of buffers

bytes (guint) –

number of bytes

time (guint64) –

amount of time

Constants

GST_TYPE_DATA_QUEUE

#define GST_TYPE_DATA_QUEUE \
  (gst_data_queue_get_type())

Callbacks

GstDataQueueCheckFullFunction

gboolean
(*GstDataQueueCheckFullFunction) (GstDataQueue * queue,
                                  guint visible,
                                  guint bytes,
                                  guint64 time,
                                  gpointer checkdata)

The prototype of the function used to inform the queue that it should be considered as full.

Parameters:

queue –

a GstDataQueue.

visible –

The number of visible items currently in the queue.

bytes –

The amount of bytes currently in the queue.

time –

The accumulated duration of the items currently in the queue.

checkdata –

The gpointer registered when the GstDataQueue was created.

Returns –

TRUE if the queue should be considered full.

GstDataQueueEmptyCallback

(*GstDataQueueEmptyCallback) (GstDataQueue * queue,
                              gpointer checkdata)

Parameters:

queue –

No description available

checkdata –

No description available

GstBase.DataQueueEmptyCallback

function GstBase.DataQueueEmptyCallback(queue: GstBase.DataQueue, checkdata: Object): {
    // javascript wrapper for 'GstDataQueueEmptyCallback'
}

Parameters:

queue (GstBase.DataQueue) –

No description available

checkdata (Object) –

No description available

GstBase.DataQueueEmptyCallback

def GstBase.DataQueueEmptyCallback (queue, checkdata):
    #python wrapper for 'GstDataQueueEmptyCallback'

Parameters:

queue (GstBase.DataQueue) –

No description available

checkdata (object) –

No description available

GstDataQueueFullCallback

(*GstDataQueueFullCallback) (GstDataQueue * queue,
                             gpointer checkdata)

Parameters:

queue –

No description available

checkdata –

No description available

GstBase.DataQueueFullCallback

function GstBase.DataQueueFullCallback(queue: GstBase.DataQueue, checkdata: Object): {
    // javascript wrapper for 'GstDataQueueFullCallback'
}

Parameters:

queue (GstBase.DataQueue) –

No description available

checkdata (Object) –

No description available

GstBase.DataQueueFullCallback

def GstBase.DataQueueFullCallback (queue, checkdata):
    #python wrapper for 'GstDataQueueFullCallback'

Parameters:

queue (GstBase.DataQueue) –

No description available

checkdata (object) –

No description available

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