The code below could be removed from setup_sinks() as it does nothing and it seems the "object" should be unreffed in order to avoid leaked reference:

  /* now actually connect everything */
  g_object_get (G_OBJECT (play_base_bin), "stream-info", &streaminfo, NULL);
  for (s = streaminfo; s; s = g_list_next (s)) {
    GObject *obj = G_OBJECT (s->data);
    gint type;
    GstObject *object;

    g_object_get (obj, "type", &type, NULL);
    g_object_get (obj, "object", &object, NULL);
  }