diff --git a/libavcodec/vc1.c b/libavcodec/vc1.c
index a6a7bac239..3882816c78 100644
--- a/libavcodec/vc1.c
+++ b/libavcodec/vc1.c
@@ -580,6 +580,8 @@ int ff_vc1_parse_frame_header(VC1Context *v, GetBitContext* gb)
 {
     int pqindex, lowquant, status;
 
+    v->field_mode = 0;
+    v->fcm = 0;
     if (v->finterpflag)
         v->interpfrm = get_bits1(gb);
     if (!v->s.avctx->codec)