+DEFINE_SUB_MAKEFUNC(source_description)
+DEFINE_SUB_ADDFUNC(source_description)
+DEFINE_SUB_FINDFUNC(source_description)
+DEFINE_SUB_REMOVEFUNC(source_description)
+DEFINE_SUB_MOVEFUNC(source_description)
+
+DEFINE_STRING_CB(source_description, sub_sour_caln_medi_start, media)
+
+DEFINE_ADDFUNC2(source_description, user_data, extra)