diff --git a/lib_com/tns_base.c b/lib_com/tns_base.c
index 5009389940a452825ce6868366b38c87093a9d39..200bf1a788edbcce6d57a0a6db162cedd0a33654 100644
--- a/lib_com/tns_base.c
+++ b/lib_com/tns_base.c
@@ -600,7 +600,7 @@ Word16 ITF_Detect_ivas_fx(
         assert(n < (Word16)(sizeof(tmpbuf)/sizeof(Word16)));
         FOR (i = 0; i < n; i++)
         {
-            tmpbuf[i] = round_fx(L_shl(pSpectrum[iStartLine+i-IGF_START_MN], shift));
+            tmpbuf[i] = round_fx_o(L_shl(pSpectrum[iStartLine+i-IGF_START_MN], shift), &Overflow);
         }
 
         FOR (lag = 0; lag <= maxOrder; lag++)
diff --git a/lib_dec/dec_tcx.c b/lib_dec/dec_tcx.c
index 46ed2dd3324dec0223470590d4db0d05e68f08b2..f011ec80ca30d7b6f0fdcd5a2f59a2337e0441bc 100644
--- a/lib_dec/dec_tcx.c
+++ b/lib_dec/dec_tcx.c
@@ -360,7 +360,7 @@ void IMDCT_flt(
                     Word32 x_fx[L_MDCT_OVLP_MAX + L_FRAME_PLUS + L_MDCT_OVLP_MAX];
                     Word16 win_fx[810] = { 0 };
                     Word16 q_x = Q16, q_win, x_e_hdrm;
-                    x_e_hdrm = sub(q_x, 13);
+                    x_e_hdrm = sub(q_x, 15);
                     q_win = q_x + x_e_hdrm - 16;
                     for ( int k = 0; k < L_ola + L_win; k++ )
                     {
@@ -2125,12 +2125,17 @@ void decoder_tcx_imdct_fx(
 
             Word16 s = getScaleFactor32(x_fx, s_max(endLine, shr(L, 1)));
             s = sub(s, 2);
-            FOR(j = 0; j < s_max(endLine, shr(L, 1)); j++)
+            IF(s <= 0)
             {
-                x_fx[j] = L_shl(x_fx[j], s);
-                move32();
+                FOR(j = 0; j < s_max(endLine, shr(L, 1)); j++)
+                {
+                    x_fx[j] = L_shl(x_fx[j], s);
+                    move32();
+                }
+                x_e = sub(x_e, s);
+            } ELSE {
+                s = 0;
             }
-            x_e = sub(x_e, s);
 
             ITF_Apply_fx( x_fx, startLine, endLine, A_itf_fx, q_a_itf, curr_order );