From a8e2883c2491bc9327bf11f806321d6f14e29b59 Mon Sep 17 00:00:00 2001
From: Sandesh Venkatesh <sandesh.venkatesh@ittiam.com>
Date: Mon, 3 Mar 2025 22:29:22 +0530
Subject: [PATCH] Fix for 3GPP issue 1325: saturation occuring in
 tcx_encoder_memory_update_ivas_fx()

Link #1325
---
 lib_enc/ivas_tcx_core_enc.c | 18 ++----------------
 lib_enc/tcx_utils_enc_fx.c  | 26 ++++++++++++++++++++------
 2 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/lib_enc/ivas_tcx_core_enc.c b/lib_enc/ivas_tcx_core_enc.c
index cecc1bf80..84bffa87c 100644
--- a/lib_enc/ivas_tcx_core_enc.c
+++ b/lib_enc/ivas_tcx_core_enc.c
@@ -570,23 +570,9 @@ void stereo_tcx_core_enc(
     move16();
     move16();
 
-    /* Scaling old_exc buffer to Q_new */
-    IF( NE_16( Q_new, Q_exc ) )
-    {
-        Scale_sig( st->hLPDmem->old_exc, L_EXC_MEM, sub( Q_new, Q_exc ) );
-    }
-
     coder_tcx_post_ivas_fx( st, st->hLPDmem, st->hTcxCfg, st->synth, A_q_fx, Aw_fx, st->wspeech_enc, Q_new );
 
-    /* Upscaling old_exc buffer */
-    s = norm_arr( st->hLPDmem->old_exc, L_EXC_MEM ) - 1;
-    Scale_sig( st->hLPDmem->old_exc, L_EXC_MEM, s );
-    IF( st->hTdCngEnc != NULL )
-    {
-        Scale_sig( st->hTdCngEnc->cng_exc2_buf, HO_HIST_SIZE * L_FFT, sub( add( shl( Q_new, 1 ), s ), Q_exc ) );
-    }
-    Q_exc = add( shl( Q_new, 1 ), s ); // 2 * Q_new + s
-    st->hLPDmem->q_lpd_old_exc = Q_exc;
+    Q_exc = Q_new; // Q_new
     move16();
 
     IF( st->enableTcxLpc )
@@ -659,7 +645,7 @@ void stereo_tcx_core_enc(
         ELSE
         {
             cng_params_upd_ivas_fx( lsp_new_fx, st->hLPDmem->old_exc + L_EXC_MEM - st->L_frame, st->L_frame, &st->hTdCngEnc->ho_circ_ptr, st->hTdCngEnc->ho_ener_circ_fx, &st->hTdCngEnc->ho_circ_size,
-                                    st->hTdCngEnc->ho_lsp_circ_fx, Q_exc, ENC, st->hTdCngEnc->ho_env_circ_fx, &st->hTdCngEnc->cng_buf_cnt, st->hTdCngEnc->cng_exc2_buf, st->hTdCngEnc->cng_Qexc_buf, st->hTdCngEnc->cng_brate_buf, st->hDtxEnc->last_active_brate, st->element_mode,
+                                    st->hTdCngEnc->ho_lsp_circ_fx, st->hLPDmem->q_lpd_old_exc, ENC, st->hTdCngEnc->ho_env_circ_fx, &st->hTdCngEnc->cng_buf_cnt, st->hTdCngEnc->cng_exc2_buf, st->hTdCngEnc->cng_Qexc_buf, st->hTdCngEnc->cng_brate_buf, st->hDtxEnc->last_active_brate, st->element_mode,
                                     st->hFdCngEnc->hFdCngCom->CngBandwidth );
         }
 
diff --git a/lib_enc/tcx_utils_enc_fx.c b/lib_enc/tcx_utils_enc_fx.c
index 5e7ca7be8..2a6f040ac 100644
--- a/lib_enc/tcx_utils_enc_fx.c
+++ b/lib_enc/tcx_utils_enc_fx.c
@@ -2814,12 +2814,12 @@ void tcx_encoder_memory_update_ivas_fx(
     /* Emphasis of synth -> synth_pe */
     tmp = synth[-( M + 1 )];
     move16();
-    E_UTIL_f_preemph2( Q_new - 1, synth - M, preemph, add( M, L_frame_glob ), &tmp );
+    E_UTIL_f_preemph2( 0, synth - M, preemph, add( M, L_frame_glob ), &tmp ); // Q_new
 
     Copy( synth + sub( L_frame_glob, M ), LPDmem->mem_syn, M );
     Copy( synth + sub( L_frame_glob, M ), LPDmem->mem_syn2, M );
     Copy( synth + sub( L_frame_glob, L_SYN_MEM ), LPDmem->mem_syn_r, L_SYN_MEM );
-    LPDmem->q_mem_syn = sub( shl( Q_new, 1 ), 1 ); // resultant q of synth after E_UTIL_f_preemph2
+    LPDmem->q_mem_syn = Q_new; // resultant q of synth after E_UTIL_f_preemph2
     move16();
 
     test();
@@ -2828,13 +2828,27 @@ void tcx_encoder_memory_update_ivas_fx(
         /* Update excitation */
         IF( LT_16( L_frame_glob, L_EXC_MEM ) )
         {
-            Copy( LPDmem->old_exc + L_frame_glob, LPDmem->old_exc, sub( L_EXC_MEM, L_frame_glob ) );
-            Scale_sig( LPDmem->old_exc, sub( L_EXC_MEM, L_frame_glob ), Q_new );                       // Q_new->2*Q_new
-            Residu3_fx( A, synth, LPDmem->old_exc + sub( L_EXC_MEM, L_frame_glob ), L_frame_glob, 1 ); // 2*Q_new
+            Word16 shift = norm_arr( LPDmem->old_exc + L_frame_glob, sub( L_EXC_MEM, L_frame_glob ) );
+            IF( LT_16( shift, sub( Q_new, LPDmem->q_lpd_old_exc ) ) )
+            {
+                Copy_Scale_sig( LPDmem->old_exc + L_frame_glob, LPDmem->old_exc, sub( L_EXC_MEM, L_frame_glob ), shift );
+                LPDmem->q_lpd_old_exc = add( LPDmem->q_lpd_old_exc, shift );
+                move16();
+                Residu3_fx( A, synth, LPDmem->old_exc + sub( L_EXC_MEM, L_frame_glob ), L_frame_glob, sub( LPDmem->q_lpd_old_exc, Q_new ) ); // LPDmem->q_lpd_old_exc
+            }
+            ELSE
+            {
+                Copy_Scale_sig( LPDmem->old_exc + L_frame_glob, LPDmem->old_exc, sub( L_EXC_MEM, L_frame_glob ), sub( Q_new, LPDmem->q_lpd_old_exc ) );
+                Residu3_fx( A, synth, LPDmem->old_exc + sub( L_EXC_MEM, L_frame_glob ), L_frame_glob, 0 ); // Q_new
+                LPDmem->q_lpd_old_exc = Q_new;
+                move16();
+            }
         }
         ELSE
         {
-            Residu3_fx( A, synth + sub( L_frame_glob, L_EXC_MEM ), LPDmem->old_exc, L_EXC_MEM, 1 ); // 2*Q_new
+            Residu3_fx( A, synth + sub( L_frame_glob, L_EXC_MEM ), LPDmem->old_exc, L_EXC_MEM, 0 ); // Q_new
+            LPDmem->q_lpd_old_exc = Q_new;
+            move16();
         }
     }
 }
-- 
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