Aggregator

Manages a set of pads with the purpose of aggregating their buffers. Control is given to the subclass when all pads have data.

Base class for mixers and muxers. Subclasses should at least implement the #GstAggregatorClass::aggregate virtual method.
Installs a #GstPadChainFunction, a #GstPadEventFullFunction and a #GstPadQueryFunction to queue all serialized data packets per sink pad. Subclasses should not overwrite those, but instead implement #GstAggregatorClass::sink_event and #GstAggregatorClass::sink_query as needed.
When data is queued on all pads, the aggregate vmethod is called.
One can peek at the data on any given GstAggregatorPad with the gstbase.aggregator_pad.AggregatorPad.peekBuffer method, and remove it from the pad with the gst_aggregator_pad_pop_buffer () method. When a buffer has been taken with pop_buffer (), a new buffer can be queued on that pad.
When gstbase.aggregator_pad.AggregatorPad.peekBuffer or gstbase.aggregator_pad.AggregatorPad.hasBuffer are called, a reference is taken to the returned buffer, which stays valid until either:
- gstbase.aggregator_pad.AggregatorPad.popBuffer is called, in which case the caller is guaranteed that the buffer they receive is the same as the peeked buffer. - gstbase.aggregator_pad.AggregatorPad.dropBuffer is called, in which case the caller is guaranteed that the dropped buffer is the one that was peeked. - the subclass implementation of #GstAggregatorClass.aggregate returns.
Subsequent calls to gstbase.aggregator_pad.AggregatorPad.peekBuffer or gstbase.aggregator_pad.AggregatorPad.hasBuffer return / check the same buffer that was returned / checked, until one of the conditions listed above is met.
Subclasses are only allowed to call these methods from the aggregate thread.
If the subclass wishes to push a buffer downstream in its aggregate implementation, it should do so through the gstbase.aggregator.Aggregator.finishBuffer method. This method will take care of sending and ordering mandatory events such as stream start, caps and segment. Buffer lists can also be pushed out with gstbase.aggregator.Aggregator.finishBufferList.
Same goes for EOS events, which should not be pushed directly by the subclass, it should instead return GST_FLOW_EOS in its aggregate implementation.
Note that the aggregator logic regarding gap event handling is to turn these into gap buffers with matching PTS and duration. It will also flag these buffers with GST_BUFFER_FLAG_GAP and GST_BUFFER_FLAG_DROPPABLE to ease their identification and subsequent processing. In addition, if the gap event was flagged with GST_GAP_FLAG_MISSING_DATA, a custom meta is added to the resulting gap buffer (GstAggregatorMissingDataMeta).
Subclasses must use (a subclass of) #GstAggregatorPad for both their sink and source pads. See gst.element_class.ElementClass.addStaticPadTemplateWithGtype.

This class used to live in gst-plugins-bad and was moved to core.

class Aggregator : Element {

gst.types.FlowReturn finishBuffer(gst.buffer.Buffer buffer);

gst.types.FlowReturn finishBufferList(gst.buffer_list.BufferList bufferlist);

void getAllocator(gst.allocator.Allocator allocator, gst.allocation_params.AllocationParams params);

gst.buffer_pool.BufferPool getBufferPool();

bool getForceLive();

bool getIgnoreInactivePads();

gst.types.ClockTime getLatency();

bool negotiate();

gst.sample.Sample peekNextSample(gstbase.aggregator_pad.AggregatorPad pad);

void selectedSamples(gst.types.ClockTime pts, gst.types.ClockTime dts, gst.types.ClockTime duration, gst.structure.Structure info);

void setForceLive(bool forceLive);

void setIgnoreInactivePads(bool ignore);

void setLatency(gst.types.ClockTime minLatency, gst.types.ClockTime maxLatency);

void setSrcCaps(gst.caps.Caps caps);

gst.types.ClockTime simpleGetNextTime();

void updateSegment(gst.segment.Segment segment);

ulong connectSamplesSelected(T callback, Flag!"After" after);

}

Members

Functions

connectSamplesSelected ulong connectSamplesSelected(T callback, Flag!"After" after): Connect to SamplesSelected signal.
finishBuffer gst.types.FlowReturn finishBuffer(gst.buffer.Buffer buffer): This method will push the provided output buffer downstream. If needed, mandatory events such as stream-start, caps, and segment events will be sent before pushing the buffer.
finishBufferList gst.types.FlowReturn finishBufferList(gst.buffer_list.BufferList bufferlist): This method will push the provided output buffer list downstream. If needed, mandatory events such as stream-start, caps, and segment events will be sent before pushing the buffer.
getAllocator void getAllocator(gst.allocator.Allocator allocator, gst.allocation_params.AllocationParams params): Lets #GstAggregator sub-classes get the memory allocator acquired by the base class and its params.
getBufferPool gst.buffer_pool.BufferPool getBufferPool()
getForceLive bool getForceLive(): Subclasses may use the return value to inform whether they should return gst.types.FlowReturn.Eos from their aggregate implementation.
getIgnoreInactivePads bool getIgnoreInactivePads()
getLatency gst.types.ClockTime getLatency(): Retrieves the latency values reported by self in response to the latency query, or GST_CLOCK_TIME_NONE if there is not live source connected and the element will not wait for the clock.
negotiate bool negotiate(): Negotiates src pad caps with downstream elements. Unmarks GST_PAD_FLAG_NEED_RECONFIGURE in any case. But marks it again if #GstAggregatorClass::negotiate fails.
peekNextSample gst.sample.Sample peekNextSample(gstbase.aggregator_pad.AggregatorPad pad): Use this function to determine what input buffers will be aggregated to produce the next output buffer. This should only be called from a #GstAggregator::samples-selected handler, and can be used to precisely control aggregating parameters for a given set of input samples.
selectedSamples void selectedSamples(gst.types.ClockTime pts, gst.types.ClockTime dts, gst.types.ClockTime duration, gst.structure.Structure info): Subclasses should call this when they have prepared the buffers they will aggregate for each of their sink pads, but before using any of the properties of the pads that govern *how* aggregation should be performed, for example z-index for video aggregators.
setForceLive void setForceLive(bool forceLive): Subclasses should call this at construction time in order for self to aggregate on a timeout even when no live source is connected.
setIgnoreInactivePads void setIgnoreInactivePads(bool ignore): Subclasses should call this when they don't want to time out waiting for a pad that hasn't yet received any buffers in live mode.
setLatency void setLatency(gst.types.ClockTime minLatency, gst.types.ClockTime maxLatency): Lets #GstAggregator sub-classes tell the baseclass what their internal latency is. Will also post a LATENCY message on the bus so the pipeline can reconfigure its global latency if the values changed.
setSrcCaps void setSrcCaps(gst.caps.Caps caps): Sets the caps to be used on the src pad.
simpleGetNextTime gst.types.ClockTime simpleGetNextTime(): This is a simple #GstAggregatorClass::get_next_time implementation that just looks at the #GstSegment on the srcpad of the aggregator and bases the next time on the running time there.
updateSegment void updateSegment(gst.segment.Segment segment): Subclasses should use this to update the segment on their source pad, instead of directly pushing new segment events downstream.

Inherited Members

From Element

makeFromUri gst.element.Element makeFromUri(gst.types.URIType type, string uri, string elementname): Creates an element for handling the given URI.
register bool register(gst.plugin.Plugin plugin, string name, uint rank, gobject.types.GType type): Create a new elementfactory capable of instantiating objects of the type and add the factory to plugin.
stateChangeReturnGetName string stateChangeReturnGetName(gst.types.StateChangeReturn stateRet): Gets a string representing the given state change result.
stateGetName string stateGetName(gst.types.State state): Gets a string representing the given state.
typeSetSkipDocumentation void typeSetSkipDocumentation(gobject.types.GType type): Marks type as "documentation should be skipped". Can be useful for dynamically registered element to be excluded from plugin documentation system.
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(gst.pad.Pad pad): Adds a pad (link point) to element. pad's parent will be set to element; see gst.object.ObjectGst.setParent for refcounting information.
addPropertyDeepNotifyWatch gulong addPropertyDeepNotifyWatch(string propertyName, bool includeValue)
addPropertyNotifyWatch gulong addPropertyNotifyWatch(string propertyName, bool includeValue)
callAsync void callAsync(gst.types.ElementCallAsyncFunc func): Calls func from another thread and passes user_data to it. This is to be used for cases when a state change has to be performed from a streaming thread, directly via gst.element.Element.setState or indirectly e.g. via SEEK events.
changeState gst.types.StateChangeReturn changeState(gst.types.StateChange transition): Perform transition on element.
continueState gst.types.StateChangeReturn continueState(gst.types.StateChangeReturn 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.types.StateChangeReturn.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.
decorateStreamId string decorateStreamId(string streamId): Creates a stream-id for element by combining the upstream information with the stream_id.
foreachPad bool foreachPad(gst.types.ElementForeachPadFunc func): Call func with user_data for each of element's pads. func will be called exactly once for each pad that exists at the time of this call, unless one of the calls to func returns false in which case we will stop iterating pads and return early. If new pads are added or pads are removed while pads are being iterated, this will not be taken into account until next time this function is used.
foreachSinkPad bool foreachSinkPad(gst.types.ElementForeachPadFunc func): Call func with user_data for each of element's sink pads. func will be called exactly once for each sink pad that exists at the time of this call, unless one of the calls to func returns false in which case we will stop iterating pads and return early. If new sink pads are added or sink pads are removed while the sink pads are being iterated, this will not be taken into account until next time this function is used.
foreachSrcPad bool foreachSrcPad(gst.types.ElementForeachPadFunc func): Call func with user_data for each of element's source pads. func will be called exactly once for each source pad that exists at the time of this call, unless one of the calls to func returns false in which case we will stop iterating pads and return early. If new source pads are added or source pads are removed while the source pads are being iterated, this will not be taken into account until next time this function is used.
getBaseTime gst.types.ClockTime 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 gst.bus.Bus getBus(): Returns the bus of the element. Note that only a #GstPipeline will provide a bus for the application.
getClock gst.clock.Clock getClock(): Gets the currently configured clock of the element. This is the clock as was last set with gst.element.Element.setClock.
getCompatiblePad gst.pad.Pad getCompatiblePad(gst.pad.Pad pad, gst.caps.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 gst.pad_template.PadTemplate getCompatiblePadTemplate(gst.pad_template.PadTemplate compattempl): Retrieves a pad template from element that is compatible with compattempl. Pads from compatible templates can be linked together.
getContext gst.context.Context getContext(string contextType): Gets the context with context_type set on the element or NULL.
getContextUnlocked gst.context.Context getContextUnlocked(string contextType): Gets the context with context_type set on the element or NULL.
getContexts gst.context.Context[] getContexts(): Gets the contexts set on the element.
getCurrentClockTime gst.types.ClockTime getCurrentClockTime(): Returns the current clock time of the element, as in, the time of the element's clock, or GST_CLOCK_TIME_NONE if there is no clock.
getCurrentRunningTime gst.types.ClockTime getCurrentRunningTime(): Returns the running time of the element. The running time is the element's clock time minus its base time. Will return GST_CLOCK_TIME_NONE if the element has no clock, or if its base time has not been set.
getFactory gst.element_factory.ElementFactory getFactory(): Retrieves the factory that was used to create this element.
getMetadata string getMetadata(string key): Get metadata with key in klass.
getPadTemplate gst.pad_template.PadTemplate getPadTemplate(string name): Retrieves a padtemplate from element with the given name.
getPadTemplateList gst.pad_template.PadTemplate[] getPadTemplateList(): Retrieves a list of the pad templates associated with element. The list must not be modified by the calling code.
getRequestPad gst.pad.Pad getRequestPad(string name): The name of this function is confusing to people learning GStreamer. gst.element.Element.requestPadSimple aims at making it more explicit it is a simplified gst.element.Element.requestPad.
getStartTime gst.types.ClockTime 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 gst.types.StateChangeReturn getState(gst.types.State state, gst.types.State pending, gst.types.ClockTime timeout): Gets the state of the element.
getStaticPad gst.pad.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 gst.iterator.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.Element.iterateSrcPads or gst.element.Element.iterateSinkPads.
iterateSinkPads gst.iterator.Iterator iterateSinkPads(): Retrieves an iterator of element's sink pads.
iterateSrcPads gst.iterator.Iterator iterateSrcPads(): Retrieves an iterator of element's source pads.
link bool link(gst.element.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(gst.element.Element dest, gst.caps.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, gst.element.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, gst.element.Element dest, string destpadname, gst.caps.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, gst.element.Element dest, string destpadname, gst.types.PadLinkCheck 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.Element.getState will return gst.types.StateChangeReturn.Async.
messageFull void messageFull(gst.types.MessageType type, glib.types.Quark domain, int code, string text, string debug_, string file, string function_, int line): Post an error, warning or info message on the bus from inside an element.
messageFullWithDetails void messageFullWithDetails(gst.types.MessageType type, glib.types.Quark domain, int code, string text, string debug_, string file, string function_, int line, gst.structure.Structure structure): 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(gst.message.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 gst.clock.Clock provideClock(): Get the clock provided by the given element. > An element is only required to provide a clock in the PAUSED > state. Some elements can provide a clock in other states.
query bool query(gst.query.Query query): Performs a query on the given element.
queryConvert bool queryConvert(gst.types.Format srcFormat, long srcVal, gst.types.Format destFormat, long destVal): Queries an element to convert src_val in src_format to dest_format.
queryDuration bool queryDuration(gst.types.Format 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(gst.types.Format 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(gst.pad.Pad pad): Makes the element free the previously requested pad as obtained with gst.element.Element.requestPad.
removePad bool removePad(gst.pad.Pad pad): Removes pad from element. pad will be destroyed if it has not been referenced elsewhere using gst.object.ObjectGst.unparent.
removePropertyNotifyWatch void removePropertyNotifyWatch(gulong watchId)
requestPad gst.pad.Pad requestPad(gst.pad_template.PadTemplate templ, string name, gst.caps.Caps caps): Retrieves a request pad from the element according to the provided template. Pad templates can be looked up using gst.element_factory.ElementFactory.getStaticPadTemplates.
requestPadSimple gst.pad.Pad requestPadSimple(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.Element.releaseRequestPad.
seek bool seek(double rate, gst.types.Format format, gst.types.SeekFlags flags, gst.types.SeekType startType, long start, gst.types.SeekType stopType, long stop): Sends a seek event to an element. See gst.event.Event.newSeek for the details of the parameters. The seek event is sent to the element using gst.element.Element.sendEvent.
seekSimple bool seekSimple(gst.types.Format format, gst.types.SeekFlags 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.Element.seek.
sendEvent bool sendEvent(gst.event.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(gst.types.ClockTime time): Set the base time of an element. See gst.element.Element.getBaseTime.
setBus void setBus(gst.bus.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(gst.clock.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(gst.context.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(gst.types.ClockTime 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 gst.types.StateChangeReturn setState(gst.types.State 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(gst.element.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, gst.element.Element dest, string destpadname): Unlinks the two named pads of the source and destination elements.
connectNoMorePads ulong connectNoMorePads(T callback, Flag!"After" after): Connect to NoMorePads signal.
connectPadAdded ulong connectPadAdded(T callback, Flag!"After" after): Connect to PadAdded signal.
connectPadRemoved ulong connectPadRemoved(T callback, Flag!"After" after): Connect to PadRemoved signal.

gstbase aggregator classes

Aggregator