ppad->event_probe_id =
gst_pad_add_probe (pad, GST_PROBE_TYPE_EVENT, pad_event_cb, ppad, NULL);
chain->pending_pads = g_list_prepend (chain->pending_pads, ppad);
ppad->event_probe_id =
gst_pad_add_probe (pad, GST_PROBE_TYPE_EVENT, pad_event_cb, ppad, NULL);
chain->pending_pads = g_list_prepend (chain->pending_pads, ppad);