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/* GStreamer aggregator base class
* Copyright (C) 2014 Mathieu Duponchelle <>
* Copyright (C) 2014 Thibault Saunier <>
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* Library General Public License for more details.
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
#ifndef __GST_AGGREGATOR_H__
#define __GST_AGGREGATOR_H__
#warning "The Base library from gst-plugins-bad is unstable API and may change in future."
#warning "You can define GST_USE_UNSTABLE_API to avoid this warning."
#include <gst/gst.h>
* GstAggregator Structs *
typedef struct _GstAggregator GstAggregator;
typedef struct _GstAggregatorPrivate GstAggregatorPrivate;
typedef struct _GstAggregatorClass GstAggregatorClass;
* GstAggregatorPad API *
#define GST_TYPE_AGGREGATOR_PAD (gst_aggregator_pad_get_type())
#define GST_AGGREGATOR_PAD_CAST(obj) ((GstAggregatorPad *)(obj))
* GstAggregatorPad Structs *
typedef struct _GstAggregatorPad GstAggregatorPad;
typedef struct _GstAggregatorPadClass GstAggregatorPadClass;
typedef struct _GstAggregatorPadPrivate GstAggregatorPadPrivate;
* GstAggregatorPad:
* @buffer: currently queued buffer.
* @segment: last segment received.
* The implementation the GstPad to use with #GstAggregator
struct _GstAggregatorPad
GstPad parent;
/* Protected by the OBJECT_LOCK */
GstSegment segment;
/* < Private > */
GstAggregatorPadPrivate * priv;
gpointer _gst_reserved[GST_PADDING];
* GstAggregatorPadClass:
* @flush: Optional
* Called when the pad has received a flush stop, this is the place
* to flush any information specific to the pad, it allows for individual
* pads to be flushed while others might not be.
struct _GstAggregatorPadClass
GstPadClass parent_class;
GstFlowReturn (*flush) (GstAggregatorPad * aggpad, GstAggregator * aggregator);
/*< private >*/
gpointer _gst_reserved[GST_PADDING_LARGE];
GType gst_aggregator_pad_get_type (void);
* GstAggregatorPad methods *
GstBuffer * gst_aggregator_pad_steal_buffer (GstAggregatorPad * pad);
GstBuffer * gst_aggregator_pad_get_buffer (GstAggregatorPad * pad);
gboolean gst_aggregator_pad_drop_buffer (GstAggregatorPad * pad);
gboolean gst_aggregator_pad_is_eos (GstAggregatorPad * pad);
* GstAggregator API *
#define GST_TYPE_AGGREGATOR (gst_aggregator_get_type())
#define GST_AGGREGATOR_CAST(obj) ((GstAggregator *)(obj))
* GstAggregator:
* @srcpad: the aggregator's source pad
* @segment: the output segment
* Aggregator base class object structure.
struct _GstAggregator
GstElement parent;
GstPad * srcpad;
/* Only access with the object lock held */
GstSegment segment;
/*< private >*/
GstAggregatorPrivate * priv;
gpointer _gst_reserved[GST_PADDING_LARGE];
* GstAggregatorClass:
* @sinkpads_type: Optional.
* The type of the pads that should be created when
* GstElement.request_new_pad is called.
* @flush: Optional.
* Called after a succesful flushing seek, once all the flush
* stops have been received. Flush pad-specific data in
* #GstAggregatorPad->flush.
* @clip: Optional.
* Called when a buffer is received on a sink pad, the task
* of clipping it and translating it to the current segment
* falls on the subclass.
* @sink_event: Optional.
* Called when an event is received on a sink pad, the subclass
* should always chain up.
* @sink_query: Optional.
* Called when a query is received on a sink pad, the subclass
* should always chain up.
* @src_event: Optional.
* Called when an event is received on the src pad, the subclass
* should always chain up.
* @src_query: Optional.
* Called when a query is received on the src pad, the subclass
* should always chain up.
* @src_activate: Optional.
* Called when the src pad is activated, it will start/stop its
* pad task right after that call.
* @aggregate: Mandatory.
* Called when buffers are queued on all sinkpads. Classes
* should iterate the GstElement->sinkpads and peek or steal
* buffers from the #GstAggregatorPads. If the subclass returns
* GST_FLOW_EOS, sending of the eos event will be taken care
* of. Once / if a buffer has been constructed from the
* aggregated buffers, the subclass should call _finish_buffer.
* @stop: Optional.
* Called when the element goes from PAUSED to READY.
* The subclass should free all resources and reset its state.
* @start: Optional.
* Called when the element goes from READY to PAUSED.
* The subclass should get ready to process
* aggregated buffers.
* @get_next_time: Optional.
* Called when the element needs to know the time of the next
* rendered buffer for live pipelines. This causes deadline
* based aggregation to occur. Defaults to returning
* GST_CLOCK_TIME_NONE causing the element to wait for buffers
* on all sink pads before aggregating.
* The aggregator base class will handle in a thread-safe way all manners of
* concurrent flushes, seeks, pad additions and removals, leaving to the
* subclass the responsibility of clipping buffers, and aggregating buffers in
* the way the implementor sees fit.
* It will also take care of event ordering (stream-start, segment, eos).
* Basically, a basic implementation will override @aggregate, and call
* _finish_buffer from inside that function.
struct _GstAggregatorClass {
GstElementClass parent_class;
GType sinkpads_type;
GstFlowReturn (*flush) (GstAggregator * aggregator);
GstFlowReturn (*clip) (GstAggregator * aggregator,
GstAggregatorPad * aggregator_pad,
GstBuffer * buf,
GstBuffer ** outbuf);
/* sinkpads virtual methods */
gboolean (*sink_event) (GstAggregator * aggregator,
GstAggregatorPad * aggregator_pad,
GstEvent * event);
gboolean (*sink_query) (GstAggregator * aggregator,
GstAggregatorPad * aggregator_pad,
GstQuery * query);
/* srcpad virtual methods */
gboolean (*src_event) (GstAggregator * aggregator,
GstEvent * event);
gboolean (*src_query) (GstAggregator * aggregator,
GstQuery * query);
gboolean (*src_activate) (GstAggregator * aggregator,
GstPadMode mode,
gboolean active);
GstFlowReturn (*aggregate) (GstAggregator * aggregator,
gboolean timeout);
gboolean (*stop) (GstAggregator * aggregator);
gboolean (*start) (GstAggregator * aggregator);
GstClockTime (*get_next_time) (GstAggregator * aggregator);
/*< private >*/
gpointer _gst_reserved[GST_PADDING_LARGE];
* GstAggregator convenience macros *
* @agg: a #GstAggregator
* Convenience macro to access the source pad of #GstAggregator
* Since: 1.6
#define GST_AGGREGATOR_SRC_PAD(agg) (((GstAggregator *)(agg))->srcpad)
* GstAggregator methods *
GstFlowReturn gst_aggregator_finish_buffer (GstAggregator * agg,
GstBuffer * buffer);
void gst_aggregator_set_src_caps (GstAggregator * agg,
GstCaps * caps);
void gst_aggregator_set_latency (GstAggregator * self,
GstClockTime min_latency,
GstClockTime max_latency);
GType gst_aggregator_get_type(void);
/* API that should eventually land in GstElement itself (FIXME) */
typedef gboolean (*GstAggregatorPadForeachFunc) (GstAggregator * aggregator,
GstAggregatorPad * aggregator_pad,
gpointer user_data);
gboolean gst_aggregator_iterate_sinkpads (GstAggregator * self,
GstAggregatorPadForeachFunc func,
gpointer user_data);
GstClockTime gst_aggregator_get_latency (GstAggregator * self);
#endif /* __GST_AGGREGATOR_H__ */