gstreamer/subprojects/gst-plugins-base/ext/gl/gstglsinkbin.c
Philippe Normand ce7b2af414 glsinkbin: Check sink property exists before attempting to read it
The same is done in the set_property function. This was noticed when attempting
to dump a pipeline containing glsinkbin sink=gtk4paintablesink to dot format.
Critical warnings were raised due to the missing force-aspect-ratio property on
that sink.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5311>
2023-09-11 07:36:21 +00:00

647 lines
21 KiB
C

/*
* GStreamer
* Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/video/videooverlay.h>
#include <gst/video/navigation.h>
#include <gst/controller/gstproxycontrolbinding.h>
#include "gstglelements.h"
#include "gstglsinkbin.h"
GST_DEBUG_CATEGORY (gst_debug_gl_sink_bin);
#define GST_CAT_DEFAULT gst_debug_gl_sink_bin
static void gst_gl_sink_bin_finalize (GObject * object);
static void gst_gl_sink_bin_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * param_spec);
static void gst_gl_sink_bin_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * param_spec);
static GstStateChangeReturn gst_gl_sink_bin_change_state (GstElement * element,
GstStateChange transition);
static void gst_gl_sink_bin_video_overlay_init (gpointer g_iface,
gpointer g_iface_data);
static void gst_gl_sink_bin_navigation_interface_init (gpointer g_iface,
gpointer g_iface_data);
static void gst_gl_sink_bin_color_balance_init (gpointer g_iface,
gpointer g_iface_data);
#define DEFAULT_SYNC TRUE
#define DEFAULT_MAX_LATENESS -1
#define DEFAULT_QOS FALSE
#define DEFAULT_ASYNC TRUE
#define DEFAULT_TS_OFFSET 0
#define DEFAULT_BLOCKSIZE 4096
#define DEFAULT_RENDER_DELAY 0
#define DEFAULT_ENABLE_LAST_SAMPLE TRUE
#define DEFAULT_THROTTLE_TIME 0
#define DEFAULT_MAX_BITRATE 0
/* GstGLColorBalance properties */
#define DEFAULT_PROP_CONTRAST 1.0
#define DEFAULT_PROP_BRIGHTNESS 0.0
#define DEFAULT_PROP_HUE 0.0
#define DEFAULT_PROP_SATURATION 1.0
enum
{
PROP_0,
PROP_FORCE_ASPECT_RATIO,
PROP_SINK,
PROP_SYNC,
PROP_MAX_LATENESS,
PROP_QOS,
PROP_ASYNC,
PROP_TS_OFFSET,
PROP_ENABLE_LAST_SAMPLE,
PROP_LAST_SAMPLE,
PROP_BLOCKSIZE,
PROP_RENDER_DELAY,
PROP_THROTTLE_TIME,
PROP_MAX_BITRATE,
PROP_CONTRAST,
PROP_BRIGHTNESS,
PROP_HUE,
PROP_SATURATION,
};
enum
{
SIGNAL_0,
SIGNAL_CREATE_ELEMENT,
SIGNAL_LAST,
};
static guint gst_gl_sink_bin_signals[SIGNAL_LAST] = { 0, };
#define gst_gl_sink_bin_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstGLSinkBin, gst_gl_sink_bin,
GST_TYPE_BIN, G_IMPLEMENT_INTERFACE (GST_TYPE_VIDEO_OVERLAY,
gst_gl_sink_bin_video_overlay_init);
G_IMPLEMENT_INTERFACE (GST_TYPE_NAVIGATION,
gst_gl_sink_bin_navigation_interface_init);
G_IMPLEMENT_INTERFACE (GST_TYPE_COLOR_BALANCE,
gst_gl_sink_bin_color_balance_init)
GST_DEBUG_CATEGORY_INIT (gst_debug_gl_sink_bin, "glimagesink", 0,
"OpenGL Video Sink Bin"));
GST_ELEMENT_REGISTER_DEFINE_WITH_CODE (glsinkbin, "glsinkbin",
GST_RANK_NONE, GST_TYPE_GL_SINK_BIN, gl_element_init (plugin));
static void
gst_gl_sink_bin_class_init (GstGLSinkBinClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *element_class;
GstCaps *upload_caps;
gobject_class = (GObjectClass *) klass;
element_class = GST_ELEMENT_CLASS (klass);
element_class->change_state = gst_gl_sink_bin_change_state;
gobject_class->set_property = gst_gl_sink_bin_set_property;
gobject_class->get_property = gst_gl_sink_bin_get_property;
gobject_class->finalize = gst_gl_sink_bin_finalize;
g_object_class_install_property (gobject_class, PROP_FORCE_ASPECT_RATIO,
g_param_spec_boolean ("force-aspect-ratio",
"Force aspect ratio",
"When enabled, scaling will respect original aspect ratio", TRUE,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_SINK,
g_param_spec_object ("sink",
"GL sink element",
"The GL sink chain to use",
GST_TYPE_ELEMENT,
GST_PARAM_MUTABLE_READY | G_PARAM_READWRITE |
G_PARAM_STATIC_STRINGS));
/* base sink */
g_object_class_install_property (gobject_class, PROP_SYNC,
g_param_spec_boolean ("sync", "Sync", "Sync on the clock", DEFAULT_SYNC,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_MAX_LATENESS,
g_param_spec_int64 ("max-lateness", "Max Lateness",
"Maximum number of nanoseconds that a buffer can be late before it "
"is dropped (-1 unlimited)", -1, G_MAXINT64, DEFAULT_MAX_LATENESS,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_QOS,
g_param_spec_boolean ("qos", "Qos",
"Generate Quality-of-Service events upstream", DEFAULT_QOS,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_ASYNC,
g_param_spec_boolean ("async", "Async",
"Go asynchronously to PAUSED", DEFAULT_ASYNC,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_TS_OFFSET,
g_param_spec_int64 ("ts-offset", "TS Offset",
"Timestamp offset in nanoseconds", G_MININT64, G_MAXINT64,
DEFAULT_TS_OFFSET, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_ENABLE_LAST_SAMPLE,
g_param_spec_boolean ("enable-last-sample", "Enable Last Buffer",
"Enable the last-sample property", DEFAULT_ENABLE_LAST_SAMPLE,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_LAST_SAMPLE,
g_param_spec_boxed ("last-sample", "Last Sample",
"The last sample received in the sink", GST_TYPE_SAMPLE,
G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_BLOCKSIZE,
g_param_spec_uint ("blocksize", "Block size",
"Size in bytes to pull per buffer (0 = default)", 0, G_MAXUINT,
DEFAULT_BLOCKSIZE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_RENDER_DELAY,
g_param_spec_uint64 ("render-delay", "Render Delay",
"Additional render delay of the sink in nanoseconds", 0, G_MAXUINT64,
DEFAULT_RENDER_DELAY, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_THROTTLE_TIME,
g_param_spec_uint64 ("throttle-time", "Throttle time",
"The time to keep between rendered buffers (0 = disabled)", 0,
G_MAXUINT64, DEFAULT_THROTTLE_TIME,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_MAX_BITRATE,
g_param_spec_uint64 ("max-bitrate", "Max Bitrate",
"The maximum bits per second to render (0 = disabled)", 0,
G_MAXUINT64, DEFAULT_MAX_BITRATE,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
/* colorbalance */
g_object_class_install_property (gobject_class, PROP_CONTRAST,
g_param_spec_double ("contrast", "Contrast", "contrast",
0.0, 2.0, DEFAULT_PROP_CONTRAST,
GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_BRIGHTNESS,
g_param_spec_double ("brightness", "Brightness", "brightness", -1.0, 1.0,
DEFAULT_PROP_BRIGHTNESS,
GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_HUE,
g_param_spec_double ("hue", "Hue", "hue", -1.0, 1.0, DEFAULT_PROP_HUE,
GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_SATURATION,
g_param_spec_double ("saturation", "Saturation", "saturation", 0.0, 2.0,
DEFAULT_PROP_SATURATION,
GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
/**
* GstGLSinkBin::create-element:
* @object: the #glsinkbin
*
* Will be emitted when we need the processing element/s that this bin will use
*
* Returns: a new #GstElement
*/
gst_gl_sink_bin_signals[SIGNAL_CREATE_ELEMENT] =
g_signal_new ("create-element", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST, 0, NULL, NULL, NULL, GST_TYPE_ELEMENT, 0);
gst_element_class_set_metadata (element_class,
"GL Sink Bin", "Sink/Video",
"Infrastructure to process GL textures",
"Matthew Waters <matthew@centricular.com>");
upload_caps = gst_gl_upload_get_input_template_caps ();
gst_element_class_add_pad_template (element_class,
gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS, upload_caps));
gst_caps_unref (upload_caps);
}
static void
gst_gl_sink_bin_init (GstGLSinkBin * self)
{
gboolean res = TRUE;
GstPad *pad;
self->upload = gst_element_factory_make ("glupload", NULL);
self->convert = gst_element_factory_make ("glcolorconvert", NULL);
self->balance = gst_element_factory_make ("glcolorbalance", NULL);
res &= gst_bin_add (GST_BIN (self), self->upload);
res &= gst_bin_add (GST_BIN (self), self->convert);
res &= gst_bin_add (GST_BIN (self), self->balance);
res &= gst_element_link_pads (self->upload, "src", self->convert, "sink");
res &= gst_element_link_pads (self->convert, "src", self->balance, "sink");
pad = gst_element_get_static_pad (self->upload, "sink");
if (!pad) {
res = FALSE;
} else {
GST_DEBUG_OBJECT (self, "setting target sink pad %" GST_PTR_FORMAT, pad);
self->sinkpad = gst_ghost_pad_new ("sink", pad);
gst_element_add_pad (GST_ELEMENT_CAST (self), self->sinkpad);
gst_object_unref (pad);
}
#define ADD_BINDING(obj,ref,prop) \
gst_object_add_control_binding (GST_OBJECT (obj), \
gst_proxy_control_binding_new (GST_OBJECT (obj), prop, \
GST_OBJECT (ref), prop));
ADD_BINDING (self->balance, self, "contrast");
ADD_BINDING (self->balance, self, "brightness");
ADD_BINDING (self->balance, self, "hue");
ADD_BINDING (self->balance, self, "saturation");
#undef ADD_BINDING
if (!res) {
GST_WARNING_OBJECT (self, "Failed to add/connect the necessary machinery");
}
gst_type_mark_as_plugin_api (GST_TYPE_GL_SINK_BIN, 0);
}
static void
gst_gl_sink_bin_finalize (GObject * object)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (object);
if (self->sink)
gst_object_unref (self->sink);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static gboolean
_connect_sink_element (GstGLSinkBin * self)
{
gst_object_set_name (GST_OBJECT (self->sink), "sink");
if (gst_bin_add (GST_BIN (self), self->sink) &&
gst_element_link_pads (self->balance, "src", self->sink, "sink"))
return TRUE;
GST_ERROR_OBJECT (self, "Failed to link sink element into the pipeline");
return FALSE;
}
/*
* @sink: (transfer full):
*/
static gboolean
gst_gl_sink_bin_set_sink (GstGLSinkBin * self, GstElement * sink)
{
g_return_val_if_fail (GST_IS_ELEMENT (sink), FALSE);
if (self->sink) {
gst_element_set_locked_state (self->sink, TRUE);
gst_bin_remove (GST_BIN (self), self->sink);
gst_element_set_state (self->sink, GST_STATE_NULL);
gst_object_unref (self->sink);
self->sink = NULL;
}
self->sink = sink;
gst_object_ref_sink (sink);
if (sink && !_connect_sink_element (self)) {
gst_object_unref (self->sink);
self->sink = NULL;
return FALSE;
}
return TRUE;
}
void
gst_gl_sink_bin_finish_init_with_element (GstGLSinkBin * self,
GstElement * element)
{
gst_gl_sink_bin_set_sink (self, element);
}
void
gst_gl_sink_bin_finish_init (GstGLSinkBin * self)
{
GstGLSinkBinClass *klass = GST_GL_SINK_BIN_GET_CLASS (self);
GstElement *element = NULL;
if (klass->create_element)
element = klass->create_element ();
if (element)
gst_gl_sink_bin_finish_init_with_element (self, element);
}
static void
gst_gl_sink_bin_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (object);
GParamSpec *sink_pspec;
switch (prop_id) {
case PROP_SINK:
gst_gl_sink_bin_set_sink (self, g_value_get_object (value));
break;
case PROP_CONTRAST:
case PROP_BRIGHTNESS:
case PROP_HUE:
case PROP_SATURATION:
if (self->balance)
g_object_set_property (G_OBJECT (self->balance), pspec->name, value);
break;
default:
if (self->sink) {
sink_pspec =
g_object_class_find_property (G_OBJECT_GET_CLASS (self->sink),
pspec->name);
if (sink_pspec
&& G_PARAM_SPEC_TYPE (sink_pspec) == G_PARAM_SPEC_TYPE (pspec)) {
g_object_set_property (G_OBJECT (self->sink), pspec->name, value);
} else {
GST_INFO ("Failed to set unmatched property %s", pspec->name);
}
}
break;
}
}
static void
gst_gl_sink_bin_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (object);
GParamSpec *sink_pspec;
switch (prop_id) {
case PROP_SINK:
g_value_set_object (value, self->sink);
break;
case PROP_CONTRAST:
case PROP_BRIGHTNESS:
case PROP_HUE:
case PROP_SATURATION:
if (self->balance)
g_object_get_property (G_OBJECT (self->balance), pspec->name, value);
break;
default:
if (self->sink) {
sink_pspec =
g_object_class_find_property (G_OBJECT_GET_CLASS (self->sink),
pspec->name);
if (sink_pspec
&& G_PARAM_SPEC_TYPE (sink_pspec) == G_PARAM_SPEC_TYPE (pspec)) {
g_object_get_property (G_OBJECT (self->sink), pspec->name, value);
} else {
GST_INFO ("Failed to get unmatched property %s", pspec->name);
}
}
break;
}
}
static GstStateChangeReturn
gst_gl_sink_bin_change_state (GstElement * element, GstStateChange transition)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (element);
GstGLSinkBinClass *klass = GST_GL_SINK_BIN_GET_CLASS (self);
GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
GST_DEBUG ("changing state: %s => %s",
gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)),
gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition)));
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
if (!self->sink) {
if (klass->create_element)
self->sink = klass->create_element ();
if (!self->sink) {
g_signal_emit (element,
gst_gl_sink_bin_signals[SIGNAL_CREATE_ELEMENT], 0, &self->sink);
if (self->sink && g_object_is_floating (self->sink))
gst_object_ref_sink (self->sink);
}
if (!self->sink) {
GST_ERROR_OBJECT (element, "Failed to retrieve element");
return GST_STATE_CHANGE_FAILURE;
}
if (!_connect_sink_element (self))
return GST_STATE_CHANGE_FAILURE;
}
break;
default:
break;
}
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
if (ret == GST_STATE_CHANGE_FAILURE)
return ret;
switch (transition) {
default:
break;
}
return ret;
}
static void
gst_gl_sink_bin_navigation_send_event (GstNavigation * navigation,
GstEvent * event)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (navigation);
GstElement *nav =
gst_bin_get_by_interface (GST_BIN (self), GST_TYPE_NAVIGATION);
if (nav) {
gst_navigation_send_event_simple (GST_NAVIGATION (nav), event);
gst_object_unref (nav);
} else {
gst_element_send_event (GST_ELEMENT (self), event);
}
}
static void
gst_gl_sink_bin_navigation_interface_init (gpointer g_iface,
gpointer g_iface_data)
{
GstNavigationInterface *iface = (GstNavigationInterface *) g_iface;
iface->send_event_simple = gst_gl_sink_bin_navigation_send_event;
}
static void
gst_gl_sink_bin_overlay_expose (GstVideoOverlay * overlay)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (overlay);
GstVideoOverlay *overlay_element = NULL;
overlay_element =
GST_VIDEO_OVERLAY (gst_bin_get_by_interface (GST_BIN (self),
GST_TYPE_VIDEO_OVERLAY));
if (overlay_element) {
gst_video_overlay_expose (overlay_element);
gst_object_unref (overlay_element);
}
}
static void
gst_gl_sink_bin_overlay_handle_events (GstVideoOverlay * overlay,
gboolean handle_events)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (overlay);
GstVideoOverlay *overlay_element = NULL;
overlay_element =
GST_VIDEO_OVERLAY (gst_bin_get_by_interface (GST_BIN (self),
GST_TYPE_VIDEO_OVERLAY));
if (overlay_element) {
gst_video_overlay_handle_events (overlay_element, handle_events);
gst_object_unref (overlay_element);
}
}
static void
gst_gl_sink_bin_overlay_set_render_rectangle (GstVideoOverlay * overlay, gint x,
gint y, gint width, gint height)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (overlay);
GstVideoOverlay *overlay_element = NULL;
overlay_element =
GST_VIDEO_OVERLAY (gst_bin_get_by_interface (GST_BIN (self),
GST_TYPE_VIDEO_OVERLAY));
if (overlay_element) {
gst_video_overlay_set_render_rectangle (overlay_element, x, y, width,
height);
gst_object_unref (overlay_element);
}
}
static void
gst_gl_sink_bin_overlay_set_window_handle (GstVideoOverlay * overlay,
guintptr handle)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (overlay);
GstVideoOverlay *overlay_element = NULL;
overlay_element =
GST_VIDEO_OVERLAY (gst_bin_get_by_interface (GST_BIN (self),
GST_TYPE_VIDEO_OVERLAY));
if (overlay_element) {
gst_video_overlay_set_window_handle (overlay_element, handle);
gst_object_unref (overlay_element);
}
}
static void
gst_gl_sink_bin_video_overlay_init (gpointer g_iface, gpointer g_iface_data)
{
GstVideoOverlayInterface *iface = (GstVideoOverlayInterface *) g_iface;
iface->expose = gst_gl_sink_bin_overlay_expose;
iface->handle_events = gst_gl_sink_bin_overlay_handle_events;
iface->set_render_rectangle = gst_gl_sink_bin_overlay_set_render_rectangle;
iface->set_window_handle = gst_gl_sink_bin_overlay_set_window_handle;
}
static const GList *
gst_gl_sink_bin_color_balance_list_channels (GstColorBalance * balance)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (balance);
GstColorBalance *balance_element = NULL;
const GList *list = NULL;
balance_element =
GST_COLOR_BALANCE (gst_bin_get_by_interface (GST_BIN (self),
GST_TYPE_COLOR_BALANCE));
if (balance_element) {
list = gst_color_balance_list_channels (balance_element);
gst_object_unref (balance_element);
}
return list;
}
static void
gst_gl_sink_bin_color_balance_set_value (GstColorBalance * balance,
GstColorBalanceChannel * channel, gint value)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (balance);
GstColorBalance *balance_element = NULL;
balance_element =
GST_COLOR_BALANCE (gst_bin_get_by_interface (GST_BIN (self),
GST_TYPE_COLOR_BALANCE));
if (balance_element) {
gst_color_balance_set_value (balance_element, channel, value);
gst_object_unref (balance_element);
}
}
static gint
gst_gl_sink_bin_color_balance_get_value (GstColorBalance * balance,
GstColorBalanceChannel * channel)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (balance);
GstColorBalance *balance_element = NULL;
gint val = 0;
balance_element =
GST_COLOR_BALANCE (gst_bin_get_by_interface (GST_BIN (self),
GST_TYPE_COLOR_BALANCE));
if (balance_element) {
val = gst_color_balance_get_value (balance_element, channel);
gst_object_unref (balance_element);
}
return val;
}
static GstColorBalanceType
gst_gl_sink_bin_color_balance_get_balance_type (GstColorBalance * balance)
{
GstGLSinkBin *self = GST_GL_SINK_BIN (balance);
GstColorBalance *balance_element = NULL;
GstColorBalanceType type = 0;
balance_element =
GST_COLOR_BALANCE (gst_bin_get_by_interface (GST_BIN (self),
GST_TYPE_COLOR_BALANCE));
if (balance_element) {
type = gst_color_balance_get_balance_type (balance_element);
gst_object_unref (balance_element);
}
return type;
}
static void
gst_gl_sink_bin_color_balance_init (gpointer g_iface, gpointer g_iface_data)
{
GstColorBalanceInterface *iface = (GstColorBalanceInterface *) g_iface;
iface->list_channels = gst_gl_sink_bin_color_balance_list_channels;
iface->set_value = gst_gl_sink_bin_color_balance_set_value;
iface->get_value = gst_gl_sink_bin_color_balance_get_value;
iface->get_balance_type = gst_gl_sink_bin_color_balance_get_balance_type;
}