poc-qt/poc006/src/qt_gst_helpers.cpp

// file: poc-qt/poc006/src/qt_gst_helpers.cpp

#include "qt_gst_helpers.h"

#include <QQuickItem>
#include <QQuickWindow>
#include <QQmlApplicationEngine>
#include <QObject>
#include <QRunnable>

#include <gst/gst.h>

class SetPlaying : public QRunnable
{
public:
    explicit SetPlaying(GstElement* pipeline)
        : pipeline_(pipeline ? GST_ELEMENT(gst_object_ref(pipeline)) : nullptr)
    {
    }

    ~SetPlaying() override
    {
        if (pipeline_) {
            gst_object_unref(pipeline_);
            pipeline_ = nullptr;
        }
    }

    void run() override
    {
        if (pipeline_) {
            gst_element_set_state(pipeline_, GST_STATE_PLAYING);
        }
    }

private:
    GstElement* pipeline_;
};

QQuickItem* find_video_item(QQmlApplicationEngine& engine)
{
    const auto roots = engine.rootObjects();
    if (roots.isEmpty()) {
        return nullptr;
    }

    auto* root_window = qobject_cast<QQuickWindow*>(roots.first());
    if (!root_window) {
        return nullptr;
    }

    return root_window->findChild<QQuickItem*>("videoItem");
}

bool bind_sink_widget(std::uintptr_t sink_ptr, QQuickItem* item)
{
    if (sink_ptr == 0 || item == nullptr) {
        return false;
    }

    auto* sink = reinterpret_cast<GstElement*>(sink_ptr);

    g_object_set(sink, "widget", item, nullptr);

    // Recommandé pour propager correctement le contexte GL Qt/GStreamer
    gst_element_set_state(sink, GST_STATE_READY);

    return true;
}

bool schedule_pipeline_play(QQmlApplicationEngine& engine, std::uintptr_t pipeline_ptr)
{
    if (pipeline_ptr == 0) {
        return false;
    }

    const auto roots = engine.rootObjects();
    if (roots.isEmpty()) {
        return false;
    }

    auto* root_window = qobject_cast<QQuickWindow*>(roots.first());
    if (!root_window) {
        return false;
    }

    auto* pipeline = reinterpret_cast<GstElement*>(pipeline_ptr);

    root_window->scheduleRenderJob(
        new SetPlaying(pipeline),
        QQuickWindow::BeforeSynchronizingStage
    );

    return true;
}