diff --git a/libavcodec/bitstream.c b/libavcodec/bitstream.c
index 8762e5f4b2..590b490527 100644
--- a/libavcodec/bitstream.c
+++ b/libavcodec/bitstream.c
@@ -226,6 +226,10 @@ static int build_table(VLC *vlc, int table_nb_bits, int nb_codes,
             /* note: realloc has been done, so reload tables */
             table = (volatile VLC_TYPE (*)[2])&vlc->table[table_index];
             table[j][0] = index; //code
+            if (table[j][0] != index) {
+                avpriv_request_sample(NULL, "strange codes");
+                return AVERROR_PATCHWELCOME;
+            }
             i = k-1;
         }
     }