playback.c

// Refer 1. http://docs.gstreamer.com/display/GstSDK/Basic+tutorial+5%3A+GUI+toolkit+integration
// Refer 2. http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-gstvideooverlay.html
// gcc playback.c -o playback `pkg-config --cflags --libs gtk+-3.0 gstreamer-1.0 gstreamer-video-1.0`
#include <gst/video/videooverlay.h>
#include <gtk/gtk.h>
#ifdef GDK_WINDOWING_X11
#include <gdk/gdkx.h>  // for GDK_WINDOW_XID
#endif
#ifdef GDK_WINDOWING_WIN32
#include <gdk/gdkwin32.h>  // for GDK_WINDOW_HWND
#endif

static guintptr video_window_handle = 0;

static GstBusSyncReply
bus_sync_handler (GstBus * bus, GstMessage * message, gpointer user_data)
{
 // ignore anything but 'prepare-window-handle' element messages
 if (!gst_is_video_overlay_prepare_window_handle_message (message))
   return GST_BUS_PASS;

 if (video_window_handle != 0) {
   GstVideoOverlay *overlay;

   // GST_MESSAGE_SRC (message) will be the video sink element
   overlay = GST_VIDEO_OVERLAY (GST_MESSAGE_SRC (message));
   gst_video_overlay_set_window_handle (overlay, video_window_handle);
 } else {
   g_warning ("Should have obtained video_window_handle by now!");
 }

 gst_message_unref (message);
 return GST_BUS_DROP;
}

static const char* get_uri()
{
	static int index = 0;
	static const char *playlist[] = {
		"http://video.blendertestbuilds.de/download.blender.org/peach/trailer_480p.mov",
		"http://video.webmfiles.org/big-buck-bunny_trailer.webm",
		"http://video.webmfiles.org/elephants-dream.webm",
		"http://docs.gstreamer.com/media/sintel_trailer-480p.webm"
	};
	if (index >= sizeof(playlist)/sizeof(playlist[0])) {
		index = 0;
	}
	g_printf("%d %d\n", sizeof(playlist), sizeof(playlist[0]));
	return playlist[index++];
}

static void
video_widget_realize_cb (GtkWidget * video_window, gpointer data)
{
#if GTK_CHECK_VERSION(2,18,0)
  // Tell Gtk+/Gdk to create a native window for this widget instead of
  // drawing onto the parent widget.
  // This is here just for pedagogical purposes, GDK_WINDOW_XID will call
  // it as well in newer Gtk versions
  if (!gdk_window_ensure_native (gtk_widget_get_window (video_window)))
    g_error ("Couldn't create native window needed for GstVideoOverlay!");
#endif

#ifdef GDK_WINDOWING_X11
  {
    gulong xid = GDK_WINDOW_XID (gtk_widget_get_window (video_window));
    video_window_handle = xid;
  }
#endif
#ifdef GDK_WINDOWING_WIN32
  {
    HWND wnd = GDK_WINDOW_HWND (gtk_widget_get_window (video_window));
    video_window_handle = (guintptr) wnd;
  }
#endif
}

static const char *stream_status[] = { "CREATE", "ENTER", "LEAVE", "DESTROY", "START", "PAUSE", "STOP" };

gboolean bus_callback(GstBus *bus, GstMessage *msg, gpointer data)
{
	GstElement *play = GST_ELEMENT(data);
	switch (GST_MESSAGE_TYPE(msg))
	{
		case GST_MESSAGE_EOS:
			g_print("%s\n", gst_message_type_get_name (GST_MESSAGE_TYPE(msg)));
			gst_element_set_state (play, GST_STATE_READY);
			g_object_set (play, "uri", get_uri(), NULL);
			gst_element_set_state (play, GST_STATE_PLAYING);
			break;
		case GST_MESSAGE_BUFFERING:
			{
				gint percentage;
				gst_message_parse_buffering (msg, &percentage);
				g_print("buffering %d%%\n", percentage);
			}
			break;
		case GST_MESSAGE_TAG:
			{
				GstTagList *tags = NULL;

				gst_message_parse_tag (msg, &tags);
				g_print ("Got tags from element %s\n", GST_OBJECT_NAME (msg->src));
				//handle_tags (tags);
				gst_tag_list_unref (tags);
			}
			break;
		case GST_MESSAGE_STATE_CHANGED:
			{
				GstState old_state, new_state;

				gst_message_parse_state_changed (msg, &old_state, &new_state, NULL);
				g_print ("Element %s state %s -> %s.\n",
						GST_OBJECT_NAME (msg->src),
						gst_element_state_get_name (old_state),
						gst_element_state_get_name (new_state));
			}
			break;
		case GST_MESSAGE_STREAM_STATUS:
			{
				GstElement *elem;
				GstStreamStatusType type;

				gst_message_parse_stream_status (msg, &type, &elem);

				g_print ("Stream %s status %s.\n",
						GST_OBJECT_NAME (elem),
						stream_status[type]);
			}
			break;
		default:
			g_print("%s\n", gst_message_type_get_name (GST_MESSAGE_TYPE(msg)));
			break;
	}
	return TRUE;
}

int
main (int argc, char **argv)
{
  GtkWidget *video_window;
  GtkWidget *app_window;
  GtkWidget *box;
  GstElement *pipeline;
  GstBus *bus;
  
  /* Initialize GTK */
  gtk_init (&argc, &argv);

  /* Initialize GStreamer */
  gst_init (&argc, &argv);

  app_window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title (GTK_WINDOW (app_window), "Media Player");
  gtk_window_set_default_size (GTK_WINDOW (app_window), 800, 600);
  g_signal_connect (app_window, "delete_event", G_CALLBACK (gtk_main_quit), NULL);
  box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
  printf("scale factor %d\n", gtk_widget_get_scale_factor (box));

  video_window = gtk_drawing_area_new ();
  g_signal_connect (video_window, "realize",
      G_CALLBACK (video_widget_realize_cb), NULL);
  gtk_widget_set_double_buffered (video_window, FALSE);

  gtk_box_pack_start (GTK_BOX (box), video_window, TRUE, TRUE, 0);

  // usually the video_window will not be directly embedded into the
  // application window like this, but there will be many other widgets
  // and the video window will be embedded in one of them instead
  gtk_container_add (GTK_CONTAINER (app_window), box);

  // show the GUI
  gtk_widget_show_all (app_window);

  // realize window now so that the video window gets created and we can
  // obtain its XID/HWND before the pipeline is started up and the videosink
  // asks for the XID/HWND of the window to render onto
  gtk_widget_realize (video_window);

  // we should have the XID/HWND now
  g_assert (video_window_handle != 0);

  pipeline = gst_element_factory_make ("playbin", "playbin");
  g_object_set (pipeline, "uri", get_uri(), NULL);

  // set up sync handler for setting the xid once the pipeline is started
  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
  gst_bus_add_watch (bus, bus_callback, pipeline);
  gst_bus_set_sync_handler (bus, (GstBusSyncHandler) bus_sync_handler, NULL,
      NULL);
  gst_object_unref (bus);

  gst_element_set_state (pipeline, GST_STATE_PLAYING);

  gtk_main ();

  gst_element_set_state (pipeline, GST_STATE_NULL);
  gst_object_unref (pipeline);

  return 0;
}