From 2eb26e382b80b3b2521c2bd405d16a3155088988 Mon Sep 17 00:00:00 2001
From: Erik Norvell <erik.norvell@ericsson.com>
Date: Thu, 4 Dec 2025 11:25:48 +0100
Subject: [PATCH] Add FIX_1461_CNG_BW_SWITCHING to address BW switching in
 Stereo CNG

---
 lib_com/options.h                |  2 +-
 lib_enc/ivas_cpe_enc_fx.c        |  9 +++++++++
 lib_enc/ivas_stereo_dft_enc_fx.c | 11 +++++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/lib_com/options.h b/lib_com/options.h
index 1a7b596d5..6ad55f796 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -96,7 +96,7 @@
 #define FIX_2015_PREMPH_SAT_ALT_PART2                   /* VA: Add missing scaling factor to be passed to AVQ_cod() */
 #define FIX_2253_CORRECT_GSC_MINIMUM_PIT_SEARCH         /* VA: Fix Issue 2253 where the encoder and decoder could get out of sync */
 #define NONBE_FIX_1967_SBA_DECODER_MONO_OUT_BIG_DIFFERENCES /* Dolby: Fix basop issue 1967 */
-
+#define FIX_1461_CNG_BW_SWITCHING                       /* Eri: float issue 1461: Stereo parameters are not updated when SID/NODATA forces BW to stay the same */
 
 /* ##################### End NON-BE switches ########################### */
 
diff --git a/lib_enc/ivas_cpe_enc_fx.c b/lib_enc/ivas_cpe_enc_fx.c
index 033e13034..4aea3ff61 100644
--- a/lib_enc/ivas_cpe_enc_fx.c
+++ b/lib_enc/ivas_cpe_enc_fx.c
@@ -130,6 +130,9 @@ ivas_error ivas_cpe_enc_fx(
     Word16 old_wsp_fx[CPE_CHANNELS][L_WSP];
     Word16 e_old_wsp[CPE_CHANNELS], q_old_wsp;
     Word16 Q_new[CPE_CHANNELS] = { 0 };
+#ifdef FIX_1461_CNG_BW_SWITCHING
+    Word16 NFFT_inner;
+#endif
     move16();
     move16();
     Word16 q_com, shift, q_min, gb;
@@ -1124,6 +1127,12 @@ ivas_error ivas_cpe_enc_fx(
             IF( EQ_32( sts[0]->core_brate, SID_2k40 ) || sts[0]->core_brate == FRAME_NO_DATA )
             {
                 /* Reconfigure DFT Stereo for inactive frames */
+#ifdef FIX_1461_CNG_BW_SWITCHING
+                /* -- nbands may need to be updated here in case the bandwidth was changed due to inactive frames */
+                NFFT_inner = shl( inner_frame_tbl[sts[0]->bwidth], 1 );
+                hCPE->hStereoDft->nbands = stereo_dft_band_config_fx( hCPE->hStereoDft->band_limits, hCPE->hStereoDft->hConfig->band_res, NFFT_inner, ENC );
+                move16();
+#endif
                 IF( EQ_32( sts[0]->core_brate, SID_2k40 ) )
                 {
                     stereo_dft_config_fx( hConfigDft, IVAS_SID_5k2, &sts[0]->bits_frame_nominal, &sts[1]->bits_frame_nominal );
diff --git a/lib_enc/ivas_stereo_dft_enc_fx.c b/lib_enc/ivas_stereo_dft_enc_fx.c
index e5522fb37..5f78defdd 100644
--- a/lib_enc/ivas_stereo_dft_enc_fx.c
+++ b/lib_enc/ivas_stereo_dft_enc_fx.c
@@ -3853,6 +3853,17 @@ static void stereo_dft_enc_compute_prm_fx(
     hStereoDft->nrg_past_pos = ( pos + 1 ) % STEREO_DFT_NRG_PAST_LEN;
     move16();
 
+#ifdef FIX_1461_CNG_BW_SWITCHING
+    /* Replicate last band for remaining bands in case the bandwidth is higher after SID/NODATA is considered */
+    FOR( i = hStereoDft->nbands; i < STEREO_DFT_BAND_MAX; i++ )
+    {
+        pPredGain[i] = pPredGain[i - 1];
+        move32();
+        pSideGain[i] = pSideGain[i - 1];
+        move32();
+    }
+#endif
+
 
     /*------------------------------------------------------------------*
      * Compute IPDs
-- 
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