diff --git a/src/tsdemux.c b/src/tsdemux.c
index e6b01846..9bd68c56 100644
--- a/src/tsdemux.c
+++ b/src/tsdemux.c
@@ -209,7 +209,10 @@ ts_recv_packet1(th_transport_t *t, uint8_t *tsb)
     ts_extract_pcr(t, st, tsb);
 
 
-  if(tsb[3] & 0xc0) {
+  if((tsb[3] & 0xc0) ||
+      (t->tht_scrambled && st->st_type != SCT_CA &&
+       st->st_type != SCT_PAT && st->st_type != SCT_PMT)) {
+
     /* scrambled stream */
     n = m = 0;