diff --git a/decoder/ixheaacd_pns_js_thumb.c b/decoder/ixheaacd_pns_js_thumb.c
index 15db806..534ec5b 100644
--- a/decoder/ixheaacd_pns_js_thumb.c
+++ b/decoder/ixheaacd_pns_js_thumb.c
@@ -354,11 +354,12 @@ VOID ixheaacd_aac_tns_process(
         scale_spec = (*ixheaacd_calc_max_spectral_line)(ptr_tmp, size);
       }
 
-      if (filter->direction != -1) {
-        position = start;
-      } else {
+      if (filter->direction == -1) {
         position = stop - 1;
         if (((win << 7) + position) < filter->order) continue;
+      } else {
+        position = start;
+        if ((((win << 7) + position) + filter->order) > MAX_BINS_LONG) continue;
       }
 
       if ((num_ch <= 2) &&