diff --git a/libavcodec/vc1.c b/libavcodec/vc1.c
index 0b69711b26..9f7f879fc3 100644
--- a/libavcodec/vc1.c
+++ b/libavcodec/vc1.c
@@ -900,6 +900,8 @@ int ff_vc1_parse_frame_header_adv(VC1Context *v, GetBitContext* gb)
             v->tff = get_bits1(gb);
             v->rff = get_bits1(gb);
         }
+    } else {
+        v->tff = 1;
     }
     if (v->panscanflag) {
         avpriv_report_missing_feature(v->s.avctx, "Pan-scan");