adding in gstreamer working although another window created and meson with it

src/main.cpp

@@ -1,10 +1,41 @@
 #include "gtkmm/button.h"
+#include <gst/gst.h>
 #include <gtkmm.h>
 #include <iostream>
 
 #include "main.h"
 
+void test_gstreamer() {
+  GstElement *pipeline = nullptr;
+  GstBus *bus = nullptr;
+  GstMessage *msg = nullptr;
+
+  // building pipeline
+  pipeline =
+      gst_parse_launch("playbin "
+                       "uri=https://www.freedesktop.org/software/gstreamer-sdk/"
+                       "data/media/sintel_trailer-480p.webm",
+                       nullptr);
+
+  // start playing
+  gst_element_set_state(pipeline, GST_STATE_PLAYING);
+
+  // wait until error or EOS ( End Of Stream )
+  bus = gst_element_get_bus(pipeline);
+  msg = gst_bus_timed_pop_filtered(
+      bus, GST_CLOCK_TIME_NONE,
+      static_cast<GstMessageType>(GST_MESSAGE_ERROR | GST_MESSAGE_EOS));
+
+  // free memory
+  if (msg != nullptr)
+    gst_message_unref(msg);
+  gst_object_unref(bus);
+  gst_element_set_state(pipeline, GST_STATE_NULL);
+  gst_object_unref(pipeline);
+}
+
 MyWindow::MyWindow() {
+
   set_title("Basic application");
 
   Gtk::Button button("start capture");
@@ -22,6 +53,9 @@ MyWindow::~MyWindow() {}
 void MyWindow::startCapture() { std::cout << "start capture" << std::endl; }
 
 int main(int argc, char **argv) {
+  gst_init(&argc, &argv);
+  test_gstreamer();
+
   auto app = Gtk::Application::create("org.gtkmm.examples.base");
 
   return app->make_window_and_run<MyWindow>(argc, argv);