diff --git a/libavcodec/flashsv.c b/libavcodec/flashsv.c
index 27f5dce1d1..9e13ea6251 100644
--- a/libavcodec/flashsv.c
+++ b/libavcodec/flashsv.c
@@ -322,9 +322,10 @@ static int flashsv_decode_frame(AVCodecContext *avctx, void *data,
         s->keyframedata = av_realloc(s->keyframedata, avpkt->size);
         memcpy(s->keyframedata, avpkt->data, avpkt->size);
     }
-    s->blocks = av_realloc(s->blocks,
-                            (v_blocks + !!v_part) * (h_blocks + !!h_part)
-                            * sizeof(s->blocks[0]));
+    if(s->ver == 2)
+        s->blocks = av_realloc(s->blocks,
+                                (v_blocks + !!v_part) * (h_blocks + !!h_part)
+                                * sizeof(s->blocks[0]));
 
     av_dlog(avctx, "image: %dx%d block: %dx%d num: %dx%d part: %dx%d\n",
             s->image_width, s->image_height, s->block_width, s->block_height,