gstreamer/subprojects/gst-plugins-good/ext/qt6/gstqml6glsink.cc
Matthew Waters 18972fc942 add new plugin for Qt 6 rendering inside a QML scene
- Based heavily on the existing Qt5 integration however:
  - The sharing of OpenGL resources is slightly different
  - The integration with the scengraph is a bit different
- Wayland, XCB and KMS have been smoke tested.  Android, MacOS/iOS,
  Windows may or may not work.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3281>
2022-11-24 16:11:04 +11:00

582 lines
18 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.
*/
/**
* SECTION:gstqml6glsink
*
* qml6glsink provides a way to render a video stream as a Qml object inside
* the Qml scene graph. This is achieved by providing the incoming OpenGL
* textures to Qt as a scene graph object.
*
* qml6glsink will attempt to retrieve the windowing system display connection
* that Qt is using (#GstGLDisplay). This may be different to any already
* existing window system display connection already in use in the pipeline for
* a number of reasons. A couple of examples of this are:
*
* 1. Adding qml6glsink to an already running pipeline
* 2. Not having any qml6glsink element start up before any
* other OpenGL-based element in the pipeline.
*
* If one of these scenarios occurs, then there will be multiple OpenGL contexts
* in use in the pipeline. This means that either the pipeline will fail to
* start up correctly, a downstream element may reject buffers, or a complete
* GPU->System memory->GPU transfer is performed for every buffer.
*
* The requirement to avoid this is that all elements share the same
* #GstGLDisplay object and as Qt cannot currently share an existing window
* system display connection, GStreamer must use the window system display
* connection provided by Qt. This window system display connection can be
* retrieved by either a qmlglsink element or a qmlgloverlay element. The
* recommended usage is to have either element (qmlglsink or qmlgloverlay)
* be the first to propagate the #GstGLDisplay for the entire pipeline to use by
* setting either element to the READY element state before any other OpenGL
* element in the pipeline.
*
* In a dynamically adding qmlglsink (or qmlgloverlay) to a pipeline case,
* there are some considerations for ensuring that the window system display
* and OpenGL contexts are compatible with Qt. When the qmlgloverlay (or
* qmlglsink) element is added and brought up to READY, it will propagate it's
* own #GstGLDisplay using the #GstContext mechanism regardless of any existing
* #GstGLDisplay used by the pipeline previously. In order for the new
* #GstGLDisplay to be used, the application must then set the provided
* #GstGLDisplay containing #GstContext on the pipeline. This may effectively
* cause each OpenGL element to replace the window system display and also the
* OpenGL context it is using. As such this process may take a significant
* amount of time and resources as objects are recreated in the new OpenGL
* context.
*
* All instances of qmlglsink and qmlgloverlay will return the exact same
* #GstGLDisplay object while the pipeline is running regardless of whether
* any qmlglsink or qmlgloverlay elements are added or removed from the
* pipeline.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstqt6elements.h"
#include "gstqml6glsink.h"
#include <QtGui/QGuiApplication>
#include <gst/gl/gstglfuncs.h>
#define GST_CAT_DEFAULT gst_debug_qml6_gl_sink
GST_DEBUG_CATEGORY (GST_CAT_DEFAULT);
static void gst_qml6_gl_sink_navigation_interface_init (GstNavigationInterface * iface);
static void gst_qml6_gl_sink_finalize (GObject * object);
static void gst_qml6_gl_sink_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * param_spec);
static void gst_qml6_gl_sink_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * param_spec);
static gboolean gst_qml6_gl_sink_stop (GstBaseSink * bsink);
static gboolean gst_qml6_gl_sink_query (GstBaseSink * bsink, GstQuery * query);
static GstStateChangeReturn
gst_qml6_gl_sink_change_state (GstElement * element, GstStateChange transition);
static void gst_qml6_gl_sink_get_times (GstBaseSink * bsink, GstBuffer * buf,
GstClockTime * start, GstClockTime * end);
static gboolean gst_qml6_gl_sink_set_caps (GstBaseSink * bsink, GstCaps * caps);
static GstFlowReturn gst_qml6_gl_sink_show_frame (GstVideoSink * bsink,
GstBuffer * buf);
static gboolean gst_qml6_gl_sink_propose_allocation (GstBaseSink * bsink,
GstQuery * query);
static GstStaticPadTemplate gst_qt_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("video/x-raw(" GST_CAPS_FEATURE_MEMORY_GL_MEMORY "), "
"format = (string) { RGB, RGBA }, "
"width = " GST_VIDEO_SIZE_RANGE ", "
"height = " GST_VIDEO_SIZE_RANGE ", "
"framerate = " GST_VIDEO_FPS_RANGE ", "
"texture-target = (string) 2D"));
#define DEFAULT_FORCE_ASPECT_RATIO TRUE
#define DEFAULT_PAR_N 0
#define DEFAULT_PAR_D 1
enum
{
ARG_0,
PROP_WIDGET,
PROP_FORCE_ASPECT_RATIO,
PROP_PIXEL_ASPECT_RATIO,
};
enum
{
SIGNAL_0,
LAST_SIGNAL
};
#define gst_qml6_gl_sink_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstQml6GLSink, gst_qml6_gl_sink,
GST_TYPE_VIDEO_SINK, GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT,
"qtsink", 0, "Qt Video Sink");
G_IMPLEMENT_INTERFACE (GST_TYPE_NAVIGATION,
gst_qml6_gl_sink_navigation_interface_init));
GST_ELEMENT_REGISTER_DEFINE_WITH_CODE (qml6glsink, "qml6glsink",
GST_RANK_NONE, GST_TYPE_QML6_GL_SINK, qt6_element_init (plugin));
static void
gst_qml6_gl_sink_class_init (GstQml6GLSinkClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
GstBaseSinkClass *gstbasesink_class;
GstVideoSinkClass *gstvideosink_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
gstbasesink_class = (GstBaseSinkClass *) klass;
gstvideosink_class = (GstVideoSinkClass *) klass;
gobject_class->set_property = gst_qml6_gl_sink_set_property;
gobject_class->get_property = gst_qml6_gl_sink_get_property;
gst_element_class_set_metadata (gstelement_class, "Qt6 Video Sink",
"Sink/Video", "A video sink that renders to a QQuickItem for Qt6",
"Matthew Waters <matthew@centricular.com>");
g_object_class_install_property (gobject_class, PROP_WIDGET,
g_param_spec_pointer ("widget", "QQuickItem",
"The QQuickItem to place in the object hierarchy",
(GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));
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",
DEFAULT_FORCE_ASPECT_RATIO,
(GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));
g_object_class_install_property (gobject_class, PROP_PIXEL_ASPECT_RATIO,
gst_param_spec_fraction ("pixel-aspect-ratio", "Pixel Aspect Ratio",
"The pixel aspect ratio of the device", DEFAULT_PAR_N, DEFAULT_PAR_D,
G_MAXINT, 1, 1, 1,
(GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));
gst_element_class_add_static_pad_template (gstelement_class, &gst_qt_sink_template);
gobject_class->finalize = gst_qml6_gl_sink_finalize;
gstelement_class->change_state = gst_qml6_gl_sink_change_state;
gstbasesink_class->query = gst_qml6_gl_sink_query;
gstbasesink_class->set_caps = gst_qml6_gl_sink_set_caps;
gstbasesink_class->get_times = gst_qml6_gl_sink_get_times;
gstbasesink_class->propose_allocation = gst_qml6_gl_sink_propose_allocation;
gstbasesink_class->stop = gst_qml6_gl_sink_stop;
gstvideosink_class->show_frame = gst_qml6_gl_sink_show_frame;
}
static void
gst_qml6_gl_sink_init (GstQml6GLSink * qt_sink)
{
qt_sink->widget = QSharedPointer<Qt6GLVideoItemInterface>();
if (qt_sink->widget)
qt_sink->widget->setSink (GST_ELEMENT_CAST (qt_sink));
}
static void
gst_qml6_gl_sink_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (object);
switch (prop_id) {
case PROP_WIDGET: {
Qt6GLVideoItem *qt_item = static_cast<Qt6GLVideoItem *> (g_value_get_pointer (value));
if (qt_item) {
qt_sink->widget = qt_item->getInterface();
if (qt_sink->widget) {
qt_sink->widget->setSink (GST_ELEMENT_CAST (qt_sink));
}
} else {
qt_sink->widget.clear();
}
break;
}
case PROP_FORCE_ASPECT_RATIO:
g_return_if_fail (qt_sink->widget);
qt_sink->widget->setForceAspectRatio (g_value_get_boolean (value));
break;
case PROP_PIXEL_ASPECT_RATIO:
g_return_if_fail (qt_sink->widget);
qt_sink->widget->setDAR (gst_value_get_fraction_numerator (value),
gst_value_get_fraction_denominator (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
_reset (GstQml6GLSink * qt_sink)
{
if (qt_sink->display) {
gst_object_unref (qt_sink->display);
qt_sink->display = NULL;
}
if (qt_sink->context) {
gst_object_unref (qt_sink->context);
qt_sink->context = NULL;
}
if (qt_sink->qt_context) {
gst_object_unref (qt_sink->qt_context);
qt_sink->qt_context = NULL;
}
}
static void
gst_qml6_gl_sink_finalize (GObject * object)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (object);
_reset (qt_sink);
qt_sink->widget.clear();
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_qml6_gl_sink_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (object);
switch (prop_id) {
case PROP_WIDGET:
/* This is not really safe - the app needs to be
* sure the widget is going to be kept alive or
* this can crash */
if (qt_sink->widget)
g_value_set_pointer (value, qt_sink->widget->videoItem());
else
g_value_set_pointer (value, NULL);
break;
case PROP_FORCE_ASPECT_RATIO:
if (qt_sink->widget)
g_value_set_boolean (value, qt_sink->widget->getForceAspectRatio ());
else
g_value_set_boolean (value, DEFAULT_FORCE_ASPECT_RATIO);
break;
case PROP_PIXEL_ASPECT_RATIO:
if (qt_sink->widget) {
gint num, den;
qt_sink->widget->getDAR (&num, &den);
gst_value_set_fraction (value, num, den);
} else {
gst_value_set_fraction (value, DEFAULT_PAR_N, DEFAULT_PAR_D);
}
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static gboolean
gst_qml6_gl_sink_query (GstBaseSink * bsink, GstQuery * query)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (bsink);
gboolean res = FALSE;
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_CONTEXT:
{
if (gst_gl_handle_context_query ((GstElement *) qt_sink, query,
qt_sink->display, qt_sink->context, qt_sink->qt_context))
return TRUE;
/* fallthrough */
}
default:
res = GST_BASE_SINK_CLASS (parent_class)->query (bsink, query);
break;
}
return res;
}
static gboolean
gst_qml6_gl_sink_stop (GstBaseSink * bsink)
{
return TRUE;
}
static GstStateChangeReturn
gst_qml6_gl_sink_change_state (GstElement * element, GstStateChange transition)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (element);
GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
QGuiApplication *app;
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:
app = static_cast<QGuiApplication *> (QCoreApplication::instance ());
if (!app) {
GST_ELEMENT_ERROR (element, RESOURCE, NOT_FOUND,
("%s", "Failed to connect to Qt"),
("%s", "Could not retrieve QGuiApplication instance"));
return GST_STATE_CHANGE_FAILURE;
}
if (!qt_sink->widget) {
GST_ELEMENT_ERROR (element, RESOURCE, NOT_FOUND,
("%s", "Required property \'widget\' not set"),
(NULL));
return GST_STATE_CHANGE_FAILURE;
}
if (!qt_sink->widget->initWinSys()) {
GST_ELEMENT_ERROR (element, RESOURCE, NOT_FOUND,
("%s", "Could not initialize window system"),
(NULL));
return GST_STATE_CHANGE_FAILURE;
}
qt_sink->display = qt_sink->widget->getDisplay();
qt_sink->context = qt_sink->widget->getContext();
qt_sink->qt_context = qt_sink->widget->getQtContext();
if (!qt_sink->display || !qt_sink->context || !qt_sink->qt_context) {
GST_ELEMENT_ERROR (element, RESOURCE, NOT_FOUND,
("%s", "Could not retrieve window system OpenGL configuration"),
(NULL));
return GST_STATE_CHANGE_FAILURE;
}
GST_OBJECT_LOCK (qt_sink->display);
gst_gl_display_add_context (qt_sink->display, qt_sink->context);
GST_OBJECT_UNLOCK (qt_sink->display);
gst_gl_element_propagate_display_context (GST_ELEMENT (qt_sink), qt_sink->display);
break;
case GST_STATE_CHANGE_READY_TO_PAUSED:
break;
case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
break;
default:
break;
}
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
if (ret == GST_STATE_CHANGE_FAILURE)
return ret;
switch (transition) {
case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
break;
case GST_STATE_CHANGE_PAUSED_TO_READY:
if (qt_sink->widget)
qt_sink->widget->setBuffer(NULL);
break;
case GST_STATE_CHANGE_READY_TO_NULL:
break;
default:
break;
}
return ret;
}
static void
gst_qml6_gl_sink_get_times (GstBaseSink * bsink, GstBuffer * buf,
GstClockTime * start, GstClockTime * end)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (bsink);
if (GST_BUFFER_TIMESTAMP_IS_VALID (buf)) {
*start = GST_BUFFER_TIMESTAMP (buf);
if (GST_BUFFER_DURATION_IS_VALID (buf))
*end = *start + GST_BUFFER_DURATION (buf);
else {
if (GST_VIDEO_INFO_FPS_N (&qt_sink->v_info) > 0) {
*end = *start +
gst_util_uint64_scale_int (GST_SECOND,
GST_VIDEO_INFO_FPS_D (&qt_sink->v_info),
GST_VIDEO_INFO_FPS_N (&qt_sink->v_info));
}
}
}
}
gboolean
gst_qml6_gl_sink_set_caps (GstBaseSink * bsink, GstCaps * caps)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (bsink);
GST_DEBUG ("set caps with %" GST_PTR_FORMAT, caps);
if (!gst_video_info_from_caps (&qt_sink->v_info, caps))
return FALSE;
if (!qt_sink->widget)
return FALSE;
return qt_sink->widget->setCaps(caps);
}
static GstFlowReturn
gst_qml6_gl_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (vsink);
GST_TRACE ("rendering buffer:%p", buf);
if (qt_sink->widget)
qt_sink->widget->setBuffer(buf);
return GST_FLOW_OK;
}
static gboolean
gst_qml6_gl_sink_propose_allocation (GstBaseSink * bsink, GstQuery * query)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (bsink);
GstBufferPool *pool;
GstStructure *config;
GstCaps *caps;
guint size;
gboolean need_pool;
if (!qt_sink->display || !qt_sink->context)
return FALSE;
gst_query_parse_allocation (query, &caps, &need_pool);
if (caps == NULL)
goto no_caps;
/* FIXME re-using buffer pool breaks renegotiation */
if ((pool = qt_sink->pool))
gst_object_ref (pool);
if (pool != NULL) {
GstCaps *pcaps;
/* we had a pool, check caps */
GST_DEBUG_OBJECT (qt_sink, "check existing pool caps");
config = gst_buffer_pool_get_config (pool);
gst_buffer_pool_config_get_params (config, &pcaps, &size, NULL, NULL);
if (!gst_caps_is_equal (caps, pcaps)) {
GST_DEBUG_OBJECT (qt_sink, "pool has different caps");
/* different caps, we can't use this pool */
gst_object_unref (pool);
pool = NULL;
}
gst_structure_free (config);
} else {
GstVideoInfo info;
if (!gst_video_info_from_caps (&info, caps))
goto invalid_caps;
/* the normal size of a frame */
size = info.size;
}
if (pool == NULL && need_pool) {
GST_DEBUG_OBJECT (qt_sink, "create new pool");
pool = gst_gl_buffer_pool_new (qt_sink->context);
config = gst_buffer_pool_get_config (pool);
gst_buffer_pool_config_set_params (config, caps, size, 0, 0);
if (!gst_buffer_pool_set_config (pool, config))
goto config_failed;
}
/* we need at least 2 buffer because we hold on to the last one */
gst_query_add_allocation_pool (query, pool, size, 2, 0);
if (pool)
gst_object_unref (pool);
/* we also support various metadata */
gst_query_add_allocation_meta (query, GST_VIDEO_META_API_TYPE, 0);
if (qt_sink->context->gl_vtable->FenceSync)
gst_query_add_allocation_meta (query, GST_GL_SYNC_META_API_TYPE, 0);
return TRUE;
/* ERRORS */
no_caps:
{
GST_DEBUG_OBJECT (bsink, "no caps specified");
return FALSE;
}
invalid_caps:
{
GST_DEBUG_OBJECT (bsink, "invalid caps specified");
return FALSE;
}
config_failed:
{
GST_DEBUG_OBJECT (bsink, "failed setting config");
return FALSE;
}
}
static void
gst_qml6_gl_sink_navigation_send_event (GstNavigation * navigation,
GstEvent * event)
{
GstQml6GLSink *qt_sink = GST_QML6_GL_SINK (navigation);
GstPad *pad;
pad = gst_pad_get_peer (GST_VIDEO_SINK_PAD (qt_sink));
GST_TRACE_OBJECT (qt_sink, "navigation event %" GST_PTR_FORMAT,
gst_event_get_structure(event));
if (GST_IS_PAD (pad) && GST_IS_EVENT (event)) {
if (!gst_pad_send_event (pad, gst_event_ref (event))) {
/* If upstream didn't handle the event we'll post a message with it
* for the application in case it wants to do something with it */
gst_element_post_message (GST_ELEMENT_CAST (qt_sink),
gst_navigation_message_new_event (GST_OBJECT_CAST (qt_sink), event));
}
gst_event_unref (event);
gst_object_unref (pad);
}
}
static void gst_qml6_gl_sink_navigation_interface_init (GstNavigationInterface * iface)
{
iface->send_event_simple = gst_qml6_gl_sink_navigation_send_event;
}