GST_CONTROL_SOURCE_CLASS  688 libs/gst/controller/gstinterpolationcontrolsource.c   GstControlSourceClass *csource_class = GST_CONTROL_SOURCE_CLASS (klass);
GST_CONTROL_SOURCE_CLASS 1081 libs/gst/controller/gstlfocontrolsource.c   GstControlSourceClass *csource_class = GST_CONTROL_SOURCE_CLASS (klass);