gstreamer/gst-libs/gst/app/gstappsink.h
Guillaume Desmottes 0a657d6db5 appsink: add API to catch events
There is currently no way for users to receive incoming events from
appsink while keeping them properly serialized with the buffers flow.
This can be especially useful when application is injecting custom
downstream events into the pipeline and needs to know when they reached
appsink.

Solving this by adding a new signal notifying about new incoming events
and a set of action signals and method to pull those events.
The API is actually pulling the samples and events all together as they
are actually fetched from the same queue.
Having a specific API to pull only events would have the side effect of
discarding samples (and pulling samples would discard events) making
this API not convenient for users.

Partially fix #247

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1046>
2021-07-22 13:56:22 +02:00

194 lines
6.3 KiB
C

/* GStreamer
* Copyright (C) 2007 David Schleef <ds@schleef.org>
*
* 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
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* 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_APP_SINK_H_
#define _GST_APP_SINK_H_
#include <gst/gst.h>
#include <gst/base/gstbasesink.h>
#include <gst/app/app-prelude.h>
G_BEGIN_DECLS
#define GST_TYPE_APP_SINK \
(gst_app_sink_get_type())
#define GST_APP_SINK(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_APP_SINK,GstAppSink))
#define GST_APP_SINK_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_APP_SINK,GstAppSinkClass))
#define GST_IS_APP_SINK(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_APP_SINK))
#define GST_IS_APP_SINK_CLASS(klass) \
(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_APP_SINK))
#define GST_APP_SINK_CAST(obj) \
((GstAppSink*)(obj))
typedef struct _GstAppSink GstAppSink;
typedef struct _GstAppSinkClass GstAppSinkClass;
typedef struct _GstAppSinkPrivate GstAppSinkPrivate;
/* FIXME 2.0: Make the instance/class struct private */
/**
* GstAppSinkCallbacks: (skip)
* @eos: Called when the end-of-stream has been reached. This callback
* is called from the streaming thread.
* @new_preroll: Called when a new preroll sample is available.
* This callback is called from the streaming thread.
* The new preroll sample can be retrieved with
* gst_app_sink_pull_preroll() either from this callback
* or from any other thread.
* @new_sample: Called when a new sample is available.
* This callback is called from the streaming thread.
* The new sample can be retrieved with
* gst_app_sink_pull_sample() either from this callback
* or from any other thread.
* @new_event: Called when a new event is available.
* This callback is called from the streaming thread.
* The new event can be retrieved with
* gst_app_sink_pull_event() either from this callback
* or from any other thread.
* The callback should return %TRUE if the event has been handled,
* %FALSE otherwise.
* Since: 1.20
*
* A set of callbacks that can be installed on the appsink with
* gst_app_sink_set_callbacks().
*/
typedef struct {
void (*eos) (GstAppSink *appsink, gpointer user_data);
GstFlowReturn (*new_preroll) (GstAppSink *appsink, gpointer user_data);
GstFlowReturn (*new_sample) (GstAppSink *appsink, gpointer user_data);
gboolean (*new_event) (GstAppSink *appsink, gpointer user_data);
/*< private >*/
gpointer _gst_reserved[GST_PADDING - 1];
} GstAppSinkCallbacks;
struct _GstAppSink
{
GstBaseSink basesink;
/*< private >*/
GstAppSinkPrivate *priv;
/*< private >*/
gpointer _gst_reserved[GST_PADDING];
};
struct _GstAppSinkClass
{
GstBaseSinkClass basesink_class;
/* signals */
void (*eos) (GstAppSink *appsink);
GstFlowReturn (*new_preroll) (GstAppSink *appsink);
GstFlowReturn (*new_sample) (GstAppSink *appsink);
/* new_event is missing as we ran out padding */
/* actions */
GstSample * (*pull_preroll) (GstAppSink *appsink);
GstSample * (*pull_sample) (GstAppSink *appsink);
GstSample * (*try_pull_preroll) (GstAppSink *appsink, GstClockTime timeout);
GstSample * (*try_pull_sample) (GstAppSink *appsink, GstClockTime timeout);
/**
* GstAppSinkClass::try_pull_object:
*
* See #GstAppSink::try-pull-object: signal.
*
* Since: 1.20
*/
GstMiniObject * (*try_pull_object) (GstAppSink *appsink, GstClockTime timeout);
/*< private >*/
gpointer _gst_reserved[GST_PADDING - 3];
};
GST_APP_API
GType gst_app_sink_get_type (void);
GST_APP_API
void gst_app_sink_set_caps (GstAppSink *appsink, const GstCaps *caps);
GST_APP_API
GstCaps * gst_app_sink_get_caps (GstAppSink *appsink);
GST_APP_API
gboolean gst_app_sink_is_eos (GstAppSink *appsink);
GST_APP_API
void gst_app_sink_set_emit_signals (GstAppSink *appsink, gboolean emit);
GST_APP_API
gboolean gst_app_sink_get_emit_signals (GstAppSink *appsink);
GST_APP_API
void gst_app_sink_set_max_buffers (GstAppSink *appsink, guint max);
GST_APP_API
guint gst_app_sink_get_max_buffers (GstAppSink *appsink);
GST_APP_API
void gst_app_sink_set_drop (GstAppSink *appsink, gboolean drop);
GST_APP_API
gboolean gst_app_sink_get_drop (GstAppSink *appsink);
GST_APP_API
void gst_app_sink_set_buffer_list_support (GstAppSink *appsink, gboolean enable_lists);
GST_APP_API
gboolean gst_app_sink_get_buffer_list_support (GstAppSink *appsink);
GST_APP_API
void gst_app_sink_set_wait_on_eos (GstAppSink *appsink, gboolean wait);
GST_APP_API
gboolean gst_app_sink_get_wait_on_eos (GstAppSink *appsink);
GST_APP_API
GstSample * gst_app_sink_pull_preroll (GstAppSink *appsink);
GST_APP_API
GstSample * gst_app_sink_pull_sample (GstAppSink *appsink);
GST_APP_API
GstMiniObject * gst_app_sink_pull_object (GstAppSink *appsink);
GST_APP_API
GstSample * gst_app_sink_try_pull_preroll (GstAppSink *appsink, GstClockTime timeout);
GST_APP_API
GstSample * gst_app_sink_try_pull_sample (GstAppSink *appsink, GstClockTime timeout);
GST_APP_API
GstMiniObject * gst_app_sink_try_pull_object (GstAppSink *appsink, GstClockTime timeout);
GST_APP_API
void gst_app_sink_set_callbacks (GstAppSink * appsink,
GstAppSinkCallbacks *callbacks,
gpointer user_data,
GDestroyNotify notify);
G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstAppSink, gst_object_unref)
G_END_DECLS
#endif