Comment 2 for bug 870767

StacktraceTop:
 gst_structure_copy (structure=0x7fdba47cad20) at gststructure.c:311
 boxed_proxy_collect_value (collect_values=<optimized out>, value=0x7fffdcc61898, n_collect_values=<optimized out>, collect_flags=<optimized out>) at /build/buildd/glib2.0-2.30.0/./gobject/gboxed.c:228
 boxed_proxy_collect_value (value=0x7fffdcc61898, n_collect_values=<optimized out>, collect_values=<optimized out>, collect_flags=<optimized out>) at /build/buildd/glib2.0-2.30.0/./gobject/gboxed.c:213
 gst_structure_id_set_valist_internal (structure=0x7fdba4656af0, fieldname=<optimized out>, varargs=0x7fffdcc618f8) at gststructure.c:647
 gst_structure_id_set (structure=<optimized out>, field=<optimized out>) at gststructure.c:681