(gst-plugin-scanner:16636): GLib-GObject-WARNING **: cannot register existing type 'ClutterGstVideoSink'

(gst-plugin-scanner:16636): GLib-GObject-CRITICAL **: g_type_add_interface_static: assertion 'G_TYPE_IS_INSTANTIATABLE (instance_type)' failed

(gst-plugin-scanner:16636): GLib-CRITICAL **: g_once_init_leave: assertion 'result != 0' failed

(gst-plugin-scanner:16636): GStreamer-CRITICAL **: gst_element_register: assertion 'g_type_is_a (type, GST_TYPE_ELEMENT)' failed
** Message: cheese-application.vala:211: Error during camera setup: One or more needed GStreamer elements are missing: cluttervideosink.