diff --git a/libavcodec/dnxhddec.c b/libavcodec/dnxhddec.c
index 2b0e2de0a0..cc011c408d 100644
--- a/libavcodec/dnxhddec.c
+++ b/libavcodec/dnxhddec.c
@@ -136,6 +136,8 @@ static int dnxhd_decode_header(DNXHDContext *ctx, AVFrame *frame,
         frame->top_field_first  = first_field ^ ctx->cur_field;
         av_log(ctx->avctx, AV_LOG_DEBUG,
                "interlaced %d, cur field %d\n", buf[5] & 3, ctx->cur_field);
+    } else {
+        ctx->cur_field = 0;
     }
 
     ctx->height = AV_RB16(buf + 0x18);