diff --git a/lib_com/ivas_cnst.h b/lib_com/ivas_cnst.h
index 2db2a465119df16834cf15fe649ff924198e9f95..72af37ef8aec31483e6bfa982721f3af967deb27 100644
--- a/lib_com/ivas_cnst.h
+++ b/lib_com/ivas_cnst.h
@@ -805,16 +805,25 @@ enum fea_names
 #define MAX_MDCT_ITD_BRATE                      IVAS_64k
 
 #define SNS_LOW_BR_MODE                         -1
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 #define SNS_NPTS                                16 /* Number of downsampled SNS parameters */
 
-#define MDCT_ST_PLC_FADEOUT_START_FRAME         3
+#define MDCT_ST_PLC_FADEOUT_MIN_NOISE_NRG       0.001f
+#ifdef FADE_TO_ZERO_FOR_TOO_LONG_FRAMELOSS
+#define MDCT_ST_PLC_FADEOUT_MAX_CONC_FRAME      2 * FRAMES_PER_SEC
+#define MDCT_ST_PLC_FADEOUT_TO_ZERO_LEN         20
+#endif
 
 typedef enum {
     EQUAL_CORES,
     TCX10_IN_0_TCX20_IN_1,
     TCX20_IN_0_TCX10_IN_1,
 } TONALMDCTCONC_NOISE_GEN_MODE;
+
+typedef enum {
+    ON_FIRST_LOST_FRAME,
+    ON_FIRST_GOOD_FRAME,
+} TONALMDCTCONC_NOISE_SHAPE_WHITENING_MODE;
 #endif
 
 
diff --git a/lib_com/ivas_prot.h b/lib_com/ivas_prot.h
index 10516239c9538b09e775285680c1f3036ea9a333..eafa392c8c60527789c7be540a09ea9372e7b48a 100644
--- a/lib_com/ivas_prot.h
+++ b/lib_com/ivas_prot.h
@@ -1950,15 +1950,12 @@ void decoder_tcx_invQ(
     const int16_t **prm_sqQ,
     int16_t *nf_seed,
     const int16_t bfi,                                          /* i  : Bad frame indicator                     */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-    const int16_t isMCT,
-#endif
     const int16_t frame_cnt                                     /* i  : frame counter in the super frame        */
 );
 
 void decoder_tcx_noisefilling(
     Decoder_State *st,                                          /* i/o: coder memory state                      */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     float concealment_noise[L_FRAME48k],
 #endif
     const float A[],                                            /* i  : coefficients NxAz[M+1]                  */
@@ -1973,7 +1970,7 @@ void decoder_tcx_noisefilling(
     const int16_t *prm_sqQ,
     int16_t nf_seed,
     const int16_t bfi,                                          /* i  : Bad frame indicator                     */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const int16_t isMCT,
 #endif
     const int16_t frame_cnt                                     /* i  : frame counter in the super frame        */
@@ -2058,7 +2055,12 @@ void decoder_tcx_IGF_stereo(
     const int16_t L_frame,                                      /* i  : frame length                            */
     const int16_t left_rect,                                    /* i  : left part is rectangular                */
     const int16_t k,                                            /* i  : Subframe index                          */
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+    const int16_t bfi,                                          /* i  : bad frame indicator                     */
+    const int16_t is_mct                                        /* i  : flag to signal MCT or SMDCT                         */
+#else
     const int16_t bfi                                           /* i  : bad frame indicator                     */
+#endif
 );
 
 void ms_processing(
@@ -2091,7 +2093,12 @@ void IGFDecApplyStereo(
     const int16_t igfGridIdx,                                   /* i  : in case of CELP->TCX switching, use 1.25 framelength */
     const int16_t *coreMsMask,
     const int16_t restrict_hopsize,
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+    const int16_t bfi,                                          /* i  : frame loss == 1, frame good == 0        */
+    const int16_t bfi_apply_damping                                  /* i  : decoder element mode                    */
+#else
     const int16_t bfi                                           /* i  : frame loss == 1, frame good == 0        */
+#endif
 );
 
 void IGFEncStereoEncoder(
@@ -5442,7 +5449,7 @@ ivas_error ivas_orient_trk_GetTrackedOrientation(
     float *roll 
 );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 void TonalMdctConceal_create_concealment_noise(
     float concealment_noise[L_FRAME48k],
     CPE_DEC_HANDLE hCPE,
@@ -5454,6 +5461,18 @@ void TonalMdctConceal_create_concealment_noise(
     const int16_t crossfade_gain,
     const TONALMDCTCONC_NOISE_GEN_MODE noise_gen_mode
 );
+
+void TonalMdctConceal_whiten_noise_shape(
+    Decoder_State *st,
+    const int16_t L_frame,
+    const TONALMDCTCONC_NOISE_SHAPE_WHITENING_MODE
+);
+
+int16_t get_igf_startline(
+    Decoder_State *st,
+    int16_t L_frame,
+    int16_t L_frameTCX
+);
 #endif
 
 float rand_triangular_signed(
diff --git a/lib_com/ivas_sns_com.c b/lib_com/ivas_sns_com.c
index 51f5fcee64c94f68dc271eb94d7c20d1abe85c51..b1555a038baa267d666d7f912414102fc34e3fd9 100644
--- a/lib_com/ivas_sns_com.c
+++ b/lib_com/ivas_sns_com.c
@@ -37,7 +37,7 @@
 #include "ivas_prot.h"
 #include "rom_com.h"
 #include <math.h>
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 #include <assert.h>
 #endif
 #ifdef DEBUGGING
@@ -45,7 +45,7 @@
 #endif
 #include "wmops.h"
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 
 /*-------------------------------------------------------------------
  * sns_compute_scf()
diff --git a/lib_com/ivas_stereo_psychlpc_com.c b/lib_com/ivas_stereo_psychlpc_com.c
index 7093a9109349c1bc02fc7a9a2e63a7af3ad3be3d..4ca10255a71a5d5da84d26eaa8e32b5474cde311 100644
--- a/lib_com/ivas_stereo_psychlpc_com.c
+++ b/lib_com/ivas_stereo_psychlpc_com.c
@@ -68,11 +68,10 @@ static void SpectrumWeighting_Init(
  *  initialize a PsychoacousticParameters structure
  *-------------------------------------------------------------------*/
 
-#ifndef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifndef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 static
 #endif
-    ivas_error
-    PsychoacousticParameters_Init(
+ivas_error PsychoacousticParameters_Init(
         const int32_t sr_core,  /* i  : sampling rate of core-coder                                     */
         const int16_t nBins,    /* i  : Number of bins (spectral lines)                                 */
         const int8_t nBands,    /* i  : Number of spectrum subbands                                     */
diff --git a/lib_com/options.h b/lib_com/options.h
index 7f07d86a9c994ae58147db937e21d8c553500979..3c30e33d86a712ab0ef4f87270d26ea19d411eb8 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -142,7 +142,8 @@
 #define DISABLE_ADAP_RES_COD_TMP                        /* temporary fix for IVAS-403, disables adaptive residual coding */
 /*#define ITD_WINNER_GAIN_MODIFY */                     /* ITD optimization - WORK IN PROGRESS */
 /*#define FIX_I4_OL_PITCH*/                             /* fix open-loop pitch used for EVS core switching */
-/*#define FIX_IVAS_185_MDCT_ST_PLC_FADEOUT*/            /* IVAS-185 fix bug in TCX-PLC fadeout for MDCT-Stereo and improve fadeout by fading to background noise instead of white noise */
+#define MDCT_STEREO_PLC_FADE_2_BG_NOISE                /* IVAS-185 fix bug in TCX-PLC fadeout for MDCT-Stereo and improve fadeout by fading to background noise instead of white noise */
+#define FADE_TO_ZERO_FOR_TOO_LONG_FRAMELOSS
 /*#define FIX_I1_113*/                                  /* under review : MCT bit distribution optimization for SBA high bitrates*/
 
 #define FIX_I106_TDREND_5MS                             /* Issue 106: 5 ms update rate in TD object renderer */
diff --git a/lib_com/prot.h b/lib_com/prot.h
index 4c91c8cd52b0e321b8a24d216eb733209d5967e1..f793d75bb7da3b2f26f80e779bb18da3bd909cd2 100644
--- a/lib_com/prot.h
+++ b/lib_com/prot.h
@@ -5145,7 +5145,7 @@ void decod_amr_wb(
 ivas_error init_decoder(
     Decoder_State *st,   /* o  : Decoder static variables structure        */
     const int16_t idchan /* i  : channel ID                                */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const MC_MODE mc_mode /* i  : MC mode                             */
 #endif
@@ -6776,7 +6776,7 @@ void enc_acelp_tcx_main(
 void getTCXMode(
     Decoder_State *st, /* i/o: decoder memory state                */
     Decoder_State *st0 /* i  : bitstream                           */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const int16_t MCT_flag
 #endif
@@ -7893,7 +7893,7 @@ void decoder_tcx_post(
     float *synthFB,
     float *A,
     const int16_t bfi
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const int16_t isMCT
 #endif
@@ -7949,7 +7949,7 @@ void decoder_acelp(
 void writeTCXMode(
     Encoder_State *st,     /* i/o: encoder state structure     */
     BSTR_ENC_HANDLE hBstr, /* i/o: bitstream handle            */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const int16_t is_mct,
 #endif
     int16_t *nbits_start /* o  : nbits start                 */
@@ -8140,7 +8140,7 @@ void con_tcx(
     const float coh,        /* i  : coherence of stereo signal  */
     int16_t *noise_seed,    /* i/o: noise seed for stereo       */
     const int16_t only_left /* i  : TD-PLC only in left channel */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const float *A_cng
 #endif
@@ -8689,7 +8689,7 @@ void configureFdCngDec(
 
 void ApplyFdCng(
     float *timeDomainInput,
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     float *powerSpectrum,
 #endif
     float **realBuffer, /* i/o: Real part of the buffer                 */
@@ -8700,7 +8700,7 @@ void ApplyFdCng(
 
 void perform_noise_estimation_dec(
     const float *timeDomainInput,
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     float *power_spectrum,
 #endif
     HANDLE_FD_CNG_DEC hFdCngDec,   /* i/o: FD_CNG structure                                 */
@@ -9202,7 +9202,7 @@ void open_decoder_LPD(
     const int32_t last_total_brate, /* i  : last total bitrate                  */
     const int16_t bwidth,           /* i  : audio bandwidth                     */
     const int16_t is_mct,           /* i  : MCT mode flag                       */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const int16_t last_element_mode,
 #endif
     const int16_t is_init /* i  : indicate call during initialization */
@@ -9245,7 +9245,7 @@ void mode_switch_decoder_LPD(
     const int32_t last_total_brate, /* i  : last frame total bitrate        */
     const int16_t frame_size_index, /* i  : index determining the frame size*/
     const int16_t is_mct            /* i  : MCT mode flag                   */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const int16_t last_element_mode /* i  : last element mode               */
 #endif
@@ -9529,7 +9529,7 @@ void TonalMDCTConceal_SaveFreqSignal(
     const uint16_t numSamples,
     const uint16_t nNewSamplesCore,
     const float *scaleFactors
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const int16_t infoIGFStartLine
 #endif
@@ -9567,8 +9567,9 @@ void TonalMDCTConceal_InsertNoise(
     int16_t *pSeed, /*IN/OUT*/
     const float tiltCompFactor,
     const float crossfadeGain,
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const float concealment_noise[L_FRAME48k],
+    const float cngLevelBackgroundTrace_bfi,
 #endif
     const int16_t crossOverFreq );
 
@@ -9604,7 +9605,7 @@ void RefineTonalComponents(
     float floorPowerSpectrum,
     const PsychoacousticParameters *psychParamsCurrent );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 ivas_error PsychoacousticParameters_Init(
     const int32_t sr_core,  /* i  : sampling rate of core-coder                                     */
     const int16_t nBins,    /* i  : Number of bins (spectral lines)                                 */
diff --git a/lib_dec/acelp_core_dec.c b/lib_dec/acelp_core_dec.c
index 5c601c5825375bca56befc276bdec8d527b8d506..684c12b57e3843545a0fc5ba96369ae2a49f1a0d 100644
--- a/lib_dec/acelp_core_dec.c
+++ b/lib_dec/acelp_core_dec.c
@@ -160,7 +160,7 @@ ivas_error acelp_core_dec(
                 st->hFdCngDec->hFdCngCom->sidNoiseEstLp[i] = STEREO_DFT_FD_FILT * st->hFdCngDec->hFdCngCom->sidNoiseEstLp[i] + ( 1 - STEREO_DFT_FD_FILT ) * st->hFdCngDec->hFdCngCom->sidNoiseEst[i];
             }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             ApplyFdCng( NULL, NULL, NULL, NULL, st, 0, 0 );
 #else
             ApplyFdCng( NULL, NULL, NULL, st, 0, 0 );
@@ -534,7 +534,7 @@ ivas_error acelp_core_dec(
                     {
                         st->hFdCngDec->hFdCngCom->sidNoiseEstLp[i] = STEREO_DFT_FD_FILT * st->hFdCngDec->hFdCngCom->sidNoiseEstLp[i] + ( 1 - STEREO_DFT_FD_FILT ) * st->hFdCngDec->hFdCngCom->sidNoiseEst[i];
                     }
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                     ApplyFdCng( syn, NULL, realBuffer, imagBuffer, st, 0, ( st->coder_type == AUDIO && !st->GSC_noisy_speech ) );
 #else
                     ApplyFdCng( syn, realBuffer, imagBuffer, st, 0, ( st->coder_type == AUDIO && !st->GSC_noisy_speech ) );
@@ -1123,7 +1123,7 @@ ivas_error acelp_core_dec(
             if ( st->element_mode != IVAS_CPE_TD )
             {
                 /*Noise estimate*/
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 ApplyFdCng( syn, NULL, realBuffer, imagBuffer, st, 0, ( st->coder_type == AUDIO && !st->GSC_noisy_speech ) );
 #else
                 ApplyFdCng( syn, realBuffer, imagBuffer, st, 0, ( st->coder_type == AUDIO && !st->GSC_noisy_speech ) );
@@ -1192,7 +1192,7 @@ ivas_error acelp_core_dec(
                     /*Noise estimate*/
                     if ( st->idchan == 0 && ( nchan_out == 2 || ( st->core_brate != FRAME_NO_DATA && st->core_brate != SID_2k40 ) ) )
                     {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                         ApplyFdCng( syn, NULL, realBuffer, imagBuffer, st, 0, ( st->coder_type == AUDIO && !st->GSC_noisy_speech ) );
 #else
                         ApplyFdCng( syn, realBuffer, imagBuffer, st, 0, ( st->coder_type == AUDIO && !st->GSC_noisy_speech ) );
diff --git a/lib_dec/amr_wb_dec.c b/lib_dec/amr_wb_dec.c
index c220c8201e42744efb4c0de9041e4c8d9614e23f..907d90e9abf7b1a8c3443180800c27c2193387e0 100644
--- a/lib_dec/amr_wb_dec.c
+++ b/lib_dec/amr_wb_dec.c
@@ -621,7 +621,7 @@ ivas_error amr_wb_dec(
         /*VAD only for non inactive frame*/
         st->VAD = ( st->VAD && ( st->coder_type != INACTIVE ) );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         ApplyFdCng( syn, NULL, NULL, NULL, st, 0, 0 );
 #else
         ApplyFdCng( syn, NULL, NULL, st, 0, 0 );
diff --git a/lib_dec/core_dec_init.c b/lib_dec/core_dec_init.c
index d2d94799ef04fc4ec848738aa0492f1a02226369..bc8d95e24f411f537ecdcd6c034f88d255e93d40 100644
--- a/lib_dec/core_dec_init.c
+++ b/lib_dec/core_dec_init.c
@@ -57,7 +57,7 @@ void open_decoder_LPD(
     const int32_t last_total_brate,
     const int16_t bwidth,
     const int16_t is_mct, /* i  : MCT mode flag                           */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const int16_t last_element_mode,
 #endif
     const int16_t is_init /* i  : indicate call from init_decoder() to avoid double TC initialization */
@@ -552,9 +552,8 @@ void open_decoder_LPD(
     {
         st->hTcxDec->prev_widow_left_rect = 0;
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-        /* Todo: should be considered for other stereo modes as well */
-        if ( is_init || !( st->element_mode == IVAS_CPE_MDCT && st->element_mode == last_element_mode ) )
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+        if ( is_init || is_mct || !( st->element_mode == IVAS_CPE_MDCT && st->element_mode == last_element_mode ) )
         {
             st->hTcxDec->CngLevelBackgroundTrace_bfi = PLC_MIN_CNG_LEV;
             st->hTcxDec->NoiseLevelIndex_bfi = PLC_MIN_STAT_BUFF_SIZE - 1;
diff --git a/lib_dec/core_dec_switch.c b/lib_dec/core_dec_switch.c
index f952a8638fa668f270c78e33c042b62624a2b668..c2084f3f12332620b8c4fd55118b9d4ffc70222a 100644
--- a/lib_dec/core_dec_switch.c
+++ b/lib_dec/core_dec_switch.c
@@ -57,7 +57,7 @@ void mode_switch_decoder_LPD(
     const int32_t last_total_brate, /* i  : last frame total bitrate        */
     const int16_t frame_size_index, /* i  : index determining the frame size*/
     const int16_t is_mct            /* i  : MCT mode flag                   */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const int16_t last_element_mode /* i  : last element mode               */
 #endif
@@ -109,7 +109,7 @@ void mode_switch_decoder_LPD(
 
     if ( fscale != st->fscale || switchWB || bSwitchFromAmrwbIO || st->last_codec_mode == MODE1 || st->force_lpd_reset )
     {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         open_decoder_LPD( st, total_brate, last_total_brate, bwidth, is_mct, last_element_mode, 0 );
 #else
         open_decoder_LPD( st, total_brate, last_total_brate, bwidth, is_mct, 0 );
diff --git a/lib_dec/dec_LPD.c b/lib_dec/dec_LPD.c
index 422104ac4380f7df7ea72735711ed598f66cd161..a28630886e53ebbfbbe27405a53494f90ed6d3c4 100644
--- a/lib_dec/dec_LPD.c
+++ b/lib_dec/dec_LPD.c
@@ -478,7 +478,7 @@ void decoder_LPD(
         if ( bfi && st->last_core != ACELP_CORE )
         {
             /* PLC: [TCX: TD PLC] */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             con_tcx( st, &synthFB[0], -1.f, NULL, 0, NULL );
 #else
             con_tcx( st, &synthFB[0], -1.f, NULL, 0 );
@@ -650,7 +650,7 @@ void decoder_LPD(
             TonalMDCTConceal_SaveTimeSignal( st->hTonalMDCTConc, synthFB, L_frameTCX );
         }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         decoder_tcx_post( st, synth, synthFB, Aq, bfi, 0 );
 #else
         decoder_tcx_post( st, synth, synthFB, Aq, bfi );
diff --git a/lib_dec/dec_acelp_tcx_main.c b/lib_dec/dec_acelp_tcx_main.c
index b1bfd3e225d87eb29551e5ef57848bd16c7b0f7c..1ca75fff209bdd9102d3329d73861c68aa90f5e2 100644
--- a/lib_dec/dec_acelp_tcx_main.c
+++ b/lib_dec/dec_acelp_tcx_main.c
@@ -198,7 +198,7 @@ static void decode_frame_type(
             st->rate_switching_init = 1;
 
             /* Reconf Core */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             mode_switch_decoder_LPD( st, st->bwidth, st->total_brate, st->last_total_brate, frame_size_index, 0, st->element_mode );
 #else
             mode_switch_decoder_LPD( st, st->bwidth, st->total_brate, st->last_total_brate, frame_size_index, 0 );
diff --git a/lib_dec/dec_prm.c b/lib_dec/dec_prm.c
index 37c64f18a3b4106c47ad3329135875d13ad56ac3..925b561fd6ad28365bd111442e22557fb11e7669 100644
--- a/lib_dec/dec_prm.c
+++ b/lib_dec/dec_prm.c
@@ -55,7 +55,7 @@
 void getTCXMode(
     Decoder_State *st, /* i/o: decoder memory state          */
     Decoder_State *st0 /* i  : bitstream                     */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const int16_t MCT_flag
 #endif
@@ -94,7 +94,7 @@ void getTCXMode(
         }
 
         st->coder_type = INACTIVE;
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         if ( st->element_mode == IVAS_CPE_MDCT && !MCT_flag )
         {
             st->VAD = get_next_indice( st0, 1 );
@@ -793,7 +793,7 @@ void dec_prm(
      *--------------------------------------------------------------------------------*/
 
     /* Modes (ACE_GC, ACE_UC, TCX20, TCX10...) */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     getTCXMode( st, st, 0 /* <- MCT_flag */ );
 #else
     getTCXMode( st, st );
diff --git a/lib_dec/dec_tcx.c b/lib_dec/dec_tcx.c
index ae5faa4d73a1dd7473a6350b7892f9353f76cc66..502433517e87c41442cc4afa9590b1f6d85bc953 100644
--- a/lib_dec/dec_tcx.c
+++ b/lib_dec/dec_tcx.c
@@ -98,13 +98,9 @@ void decoder_tcx(
 
     init_tcx_info( st, L_frame_glob, L_frameTCX_glob, frame_cnt, bfi, &tcx_offset, &tcx_offsetFB, &L_frame, &L_frameTCX, &left_rect, &L_spec );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-    decoder_tcx_invQ( st, prm, A, Aind, L_spec, L_frame, L_frameTCX, &x[0], &gainlpc2[0], &xn_buf[0], &fUseTns, &tnsData, &gain_tcx, &prm_sqQ, &nf_seed, bfi, 0, /* <- isMCT */ frame_cnt );
-#else
     decoder_tcx_invQ( st, prm, A, Aind, L_spec, L_frame, L_frameTCX, &x[0], &gainlpc2[0], &xn_buf[0], &fUseTns, &tnsData, &gain_tcx, &prm_sqQ, &nf_seed, bfi, frame_cnt );
-#endif
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     decoder_tcx_noisefilling( st, NULL, A, L_frameTCX_glob, L_spec, L_frame, L_frameTCX, &x[0], &gainlpc2[0], &tmp_concealment_method, gain_tcx, prm_sqQ, nf_seed, bfi, 0, frame_cnt );
 #else
     decoder_tcx_noisefilling( st, A, L_frameTCX_glob, L_spec, L_frame, L_frameTCX, &x[0], &gainlpc2[0], &tmp_concealment_method, gain_tcx, prm_sqQ, nf_seed, bfi, frame_cnt );
@@ -133,7 +129,7 @@ void decoder_tcx_post(
     float *synthFB,
     float *A,
     const int16_t bfi
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const int16_t isMCT
 #endif
@@ -188,7 +184,7 @@ void decoder_tcx_post(
 
     /* PLC: [TCX: Fade-out]
      * PLC: update or retrieve the background level */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     if ( bfi == 0 && st->tcxonly && ( st->element_mode != IVAS_CPE_MDCT || isMCT ) && st->clas_dec == UNVOICED_CLAS )
 #else
     if ( bfi == 0 && st->tcxonly && st->clas_dec == UNVOICED_CLAS )
@@ -206,6 +202,20 @@ void decoder_tcx_post(
         if ( st->tcxonly )
         {
             gainCNG = hTcxDec->CngLevelBackgroundTrace_bfi / ( level_syn + 0.01f );
+#ifdef FADE_TO_ZERO_FOR_TOO_LONG_FRAMELOSS
+
+            if ( st->element_mode == IVAS_CPE_MDCT && ! isMCT )
+            {
+                if ( st->nbLostCmpt > MDCT_ST_PLC_FADEOUT_MAX_CONC_FRAME + MDCT_ST_PLC_FADEOUT_TO_ZERO_LEN )
+                {
+                    gainCNG = 0.f;
+                }
+                else if ( st->nbLostCmpt > MDCT_ST_PLC_FADEOUT_MAX_CONC_FRAME )
+                {
+                    gainCNG *= 1.f - (float) ( st->nbLostCmpt - MDCT_ST_PLC_FADEOUT_MAX_CONC_FRAME ) / MDCT_ST_PLC_FADEOUT_TO_ZERO_LEN;
+                }
+            }
+#endif
         }
         else
         {
@@ -696,9 +706,6 @@ void decoder_tcx_invQ(
     const int16_t **prm_sqQ1,
     int16_t *nf_seed,
     const int16_t bfi, /* i  : Bad frame indicator                     */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-    const int16_t isMCT,
-#endif
     const int16_t frame_cnt /* i  : frame counter in the super frame        */
 )
 {
@@ -913,16 +920,7 @@ void decoder_tcx_invQ(
 
             hTcxDec->damping = 1;
         }
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-        else if ( st->element_mode == IVAS_CPE_MDCT && st->nbLostCmpt >= MDCT_ST_PLC_FADEOUT_START_FRAME )
-        {
-            *gain_tcx = hTcxDec->old_gaintcx_bfi;
-            hTcxDec->damping = Damping_fact( st->coder_type, st->nbLostCmpt - MDCT_ST_PLC_FADEOUT_START_FRAME, st->last_good, st->stab_fac, &( st->lp_gainp ), st->last_core );
-        }
-        else if ( st->element_mode != IVAS_CPE_MDCT || !isMCT )
-#else
         else
-#endif
         {
             *gain_tcx = hTcxDec->old_gaintcx_bfi;
             hTcxDec->damping = Damping_fact( st->coder_type, st->nbLostCmpt, st->last_good, st->stab_fac, &( st->lp_gainp ), st->last_core );
@@ -1079,7 +1077,7 @@ void decoder_tcx_invQ(
 
 void decoder_tcx_noisefilling(
     Decoder_State *st, /* i/o: coder memory state          */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     float concealment_noise[L_FRAME48k],
 #endif
     const float A[], /* i  :  coefficients NxAz[M+1]     */
@@ -1094,7 +1092,7 @@ void decoder_tcx_noisefilling(
     const int16_t *prm_sqQ,
     int16_t nf_seed,
     const int16_t bfi, /* i  :  Bad frame indicator            */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const int16_t isMCT,
 #endif
     const int16_t frame_cnt /* i  : frame counter in the super frame*/
@@ -1120,6 +1118,9 @@ void decoder_tcx_noisefilling(
      *-----------------------------------------------------------------*/
 
     /* Init lengths */
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+    infoIGFStartLine = get_igf_startline( st, L_frame, L_frameTCX );
+#else
     if ( st->igf == 0 )
     {
         if ( st->narrowBand == 0 )
@@ -1137,6 +1138,7 @@ void decoder_tcx_noisefilling(
     {
         infoIGFStartLine = min( st->hIGFDec->infoIGFStartLine, L_frameTCX );
     }
+#endif
 
     noiseFillingSize = L_spec;
     if ( st->igf )
@@ -1248,7 +1250,7 @@ void decoder_tcx_noisefilling(
         if ( !bfi && st->element_mode != IVAS_CPE_MDCT )
 
         {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             TonalMDCTConceal_SaveFreqSignal( st->hTonalMDCTConc, x, L_frameTCX, L_frame, gainlpc2, infoIGFStartLine );
 #else
             TonalMDCTConceal_SaveFreqSignal( st->hTonalMDCTConc, x, L_frameTCX, L_frame, gainlpc2 );
@@ -1261,8 +1263,8 @@ void decoder_tcx_noisefilling(
             {
                 /* set f to 1 to not fade out */
                 /* set f to 0 to immediately switch to white noise */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-                if ( st->tcxonly && st->element_mode != IVAS_CPE_MDCT )
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+                if ( st->tcxonly && ( st->element_mode != IVAS_CPE_MDCT || isMCT ) )
 #else
                 if ( st->tcxonly )
 #endif
@@ -1304,14 +1306,14 @@ void decoder_tcx_noisefilling(
                 noiseTiltFactor = 1.0f;
                 tcxGetNoiseFillingTilt( A, L_frame, ( total_brate >= ACELP_13k20 && !st->rf_flag ), &noiseTiltFactor );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 if ( st->element_mode == IVAS_CPE_MDCT && !isMCT )
                 {
-                    TonalMDCTConceal_InsertNoise( st->hTonalMDCTConc, x, st->tonal_mdct_plc_active, &st->seed_tcx_plc, noiseTiltFactor, f, concealment_noise, infoIGFStartLine );
+                    TonalMDCTConceal_InsertNoise( st->hTonalMDCTConc, x, st->tonal_mdct_plc_active, &st->seed_tcx_plc, noiseTiltFactor, f, concealment_noise, hTcxDec->CngLevelBackgroundTrace_bfi, infoIGFStartLine );
                 }
                 else
                 {
-                    TonalMDCTConceal_InsertNoise( st->hTonalMDCTConc, x, st->tonal_mdct_plc_active, &st->seed_tcx_plc, noiseTiltFactor, f, NULL, infoIGFStartLine );
+                    TonalMDCTConceal_InsertNoise( st->hTonalMDCTConc, x, st->tonal_mdct_plc_active, &st->seed_tcx_plc, noiseTiltFactor, f, NULL, hTcxDec->CngLevelBackgroundTrace_bfi, infoIGFStartLine );
                 }
 #else
                 TonalMDCTConceal_InsertNoise( st->hTonalMDCTConc, x, st->tonal_mdct_plc_active, &st->seed_tcx_plc, noiseTiltFactor, f, infoIGFStartLine );
@@ -1393,7 +1395,7 @@ void decoder_tcx_noiseshaping_igf(
      * Noise shaping in frequency domain (1/Wz)                  *
      *-----------------------------------------------------------*/
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     if ( st->igf && ( !bfi || ( st->element_mode == IVAS_CPE_MDCT && st->prev_bfi ) ) )
 #else
     if ( st->igf && !bfi )
@@ -1943,7 +1945,12 @@ void decoder_tcx_IGF_stereo(
     const int16_t L_frame,                   /* i  : frame length                */
     const int16_t left_rect,                 /* i  : left part is rectangular    */
     const int16_t k,                         /* i  : Subframe index              */
-    const int16_t bfi                        /* i  : bad frame indicator         */
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+    const int16_t bfi,                       /* i  : bad frame indicator         */
+    const int16_t is_mct                     /* i  : flag to signal MCT or SMDCT */
+#else
+    const int16_t bfi                       /* i  : bad frame indicator         */
+#endif
 )
 {
     int16_t coreMsMask[N_MAX];
@@ -1996,7 +2003,11 @@ void decoder_tcx_IGF_stereo(
             igfGridIdx = ( sts[0]->last_core == ACELP_CORE || ( left_rect && bfi ) ) ? IGF_GRID_LB_TRAN : IGF_GRID_LB_NORM;
         }
 
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+        IGFDecApplyStereo( sts[0]->hIGFDec, sts[1]->hIGFDec, x[0][k], x[1][k], igfGridIdx, coreMsMask, hStereoMdct->IGFStereoMode[k] == SMDCT_BW_MS, bfi, is_mct );
+#else
         IGFDecApplyStereo( sts[0]->hIGFDec, sts[1]->hIGFDec, x[0][k], x[1][k], igfGridIdx, coreMsMask, hStereoMdct->IGFStereoMode[k] == SMDCT_BW_MS, bfi );
+#endif
     }
 
     return;
diff --git a/lib_dec/er_dec_tcx.c b/lib_dec/er_dec_tcx.c
index 18a71c9939969ca0e140226fbb15ef552049de6a..d72e88da5f490c7b8181b8a6fd7085c658f9087b 100644
--- a/lib_dec/er_dec_tcx.c
+++ b/lib_dec/er_dec_tcx.c
@@ -34,6 +34,8 @@
     EVS Codec 3GPP TS26.443 Nov 04, 2021. Version 12.14.0 / 13.10.0 / 14.6.0 / 15.4.0 / 16.3.0
   ====================================================================================*/
 
+#include "cnst.h"
+#include "ivas_cnst.h"
 #include <assert.h>
 #include <stdint.h>
 #include "options.h"
@@ -57,7 +59,7 @@ void con_tcx(
     const float coh,        /* i  : coherence of stereo signal  */
     int16_t *noise_seed,    /* i/o: noise seed for stereo       */
     const int16_t only_left /* i  : TD-PLC only in left channel */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const float *A_cng
 #endif
@@ -279,19 +281,7 @@ void con_tcx(
         st->bpf_gain_param = 0;
 
         /* PLC: calculate damping factor */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-        alpha = 1.0f;
-        if ( st->element_mode == IVAS_CPE_MDCT && st->nbLostCmpt >= MDCT_ST_PLC_FADEOUT_START_FRAME )
-        {
-            alpha = Damping_fact( st->core_ext_mode, st->nbLostCmpt - MDCT_ST_PLC_FADEOUT_START_FRAME, st->last_good, st->stab_fac, &( st->lp_gainp ), 0 );
-        }
-        else if ( st->element_mode != IVAS_CPE_MDCT )
-        {
-            alpha = Damping_fact( st->core_ext_mode, st->nbLostCmpt, st->last_good, st->stab_fac, &( st->lp_gainp ), 0 );
-        }
-#else
-        alpha = Damping_fact( st->core_ext_mode, st->nbLostCmpt, st->last_good, st->stab_fac, &( st->lp_gainp ), 0 );
-#endif
+        alpha = Damping_fact( st->core_ext_mode, st->nbLostCmpt, st->last_good, st->stab_fac, &( st->lp_gainp ), ACELP_CORE );
 
         if ( st->nbLostCmpt == 1 )
         {
@@ -350,19 +340,7 @@ void con_tcx(
         set_f( pitch_buf, (float) L_SUBFR, st->nb_subfr );
 
         /* PLC: calculate damping factor */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-        alpha = 1.0f;
-        if ( st->element_mode == IVAS_CPE_MDCT && st->nbLostCmpt >= MDCT_ST_PLC_FADEOUT_START_FRAME )
-        {
-            alpha = Damping_fact( st->core_ext_mode, st->nbLostCmpt - MDCT_ST_PLC_FADEOUT_START_FRAME, st->last_good, st->stab_fac, &( st->lp_gainp ), 0 );
-        }
-        else if ( st->element_mode != IVAS_CPE_MDCT )
-        {
-            alpha = Damping_fact( st->core_ext_mode, st->nbLostCmpt, st->last_good, st->stab_fac, &( st->lp_gainp ), 0 );
-        }
-#else
-        alpha = Damping_fact( st->core_ext_mode, st->nbLostCmpt, st->last_good, st->stab_fac, &( st->lp_gainp ), 0 );
-#endif
+        alpha = Damping_fact( st->core_ext_mode, st->nbLostCmpt, st->last_good, st->stab_fac, &( st->lp_gainp ), ACELP_CORE );
     }
 
     /*-----------------------------------------------------------------*
@@ -459,7 +437,7 @@ void con_tcx(
 
     /* PLC: [TCX: Fade-out] retrieve background level */
     tmp = 1.0f;
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     if ( A_cng != NULL )
     {
         gainSynthDeemph = getLevelSynDeemph( &( tmp ), A_cng, L_frame / 4, st->preemph_fac, 1 ) / 4.f;
@@ -474,6 +452,20 @@ void con_tcx(
     if ( st->tcxonly )
     {
         gainCNG = hTcxDec->CngLevelBackgroundTrace_bfi / gainSynthDeemph;
+
+#ifdef FADE_TO_ZERO_FOR_TOO_LONG_FRAMELOSS
+        if ( st->element_mode == IVAS_CPE_MDCT && A_cng != NULL )
+        {
+            if ( st->nbLostCmpt > MDCT_ST_PLC_FADEOUT_MAX_CONC_FRAME + MDCT_ST_PLC_FADEOUT_TO_ZERO_LEN )
+            {
+                gainCNG = 0.f;
+            }
+            else if ( st->nbLostCmpt > MDCT_ST_PLC_FADEOUT_MAX_CONC_FRAME )
+            {
+                gainCNG *= 1.f - (float) ( st->nbLostCmpt - MDCT_ST_PLC_FADEOUT_MAX_CONC_FRAME ) / MDCT_ST_PLC_FADEOUT_TO_ZERO_LEN;
+            }
+        }
+#endif
     }
     else
     {
@@ -569,26 +561,13 @@ void con_tcx(
     mvr2r( buf, mem_syn, M );
 
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     if ( A_cng != NULL )
     {
-        if ( ( st->nbLostCmpt == 1 && st->idchan == 0 ) || ( st->nbLostCmpt == 2 && st->idchan == 1 ) )
-        {
-            float lsp_cng[M];
-
-            lpc_from_spectrum( st->hFdCngDec->hFdCngCom, st->hFdCngDec->hFdCngCom->startBand, st->hFdCngDec->hFdCngCom->stopFFTbin, 0.f );
-
-            a2lsp_stab( st->hFdCngDec->hFdCngCom->A_cng, lsp_cng, st->lspold_cng );
-            mvr2r( lsp_cng, st->lspold_cng, M );
-        }
-
-        if ( alpha != 1.0f )
+        if ( st->plcBackgroundNoiseUpdated && alpha != 1.0f )
         {
-            float lsp_local[M];
-            float lsp_fade[M];
-            float alpha_inv;
+            float lsp_local[M], lsp_fade[M], alpha_inv;
 
-            wmops_sub_start( "Fade LSPs" );
             alpha_inv = 1.0f - alpha;
 
             a2lsp_stab( A_local, lsp_local, lsp_local );
@@ -599,7 +578,6 @@ void con_tcx(
             }
 
             lsp2a_stab( lsp_fade, A_local, M );
-            wmops_sub_end();
         }
     }
 #endif
diff --git a/lib_dec/evs_dec.c b/lib_dec/evs_dec.c
index b51ed8d6eacb0ed9572ee56853cd5a152d1cf11b..e03b2ff2bc63b860983c33cc1b10c1d5abd95827 100644
--- a/lib_dec/evs_dec.c
+++ b/lib_dec/evs_dec.c
@@ -676,7 +676,7 @@ ivas_error evs_dec(
 
                 st->lp_noise = st->hFdCngDec->lp_noise;
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 ApplyFdCng( output, NULL, realBuffer, imagBuffer, st, concealWholeFrame, 0 );
 #else
                 ApplyFdCng( output, realBuffer, imagBuffer, st, concealWholeFrame, 0 );
diff --git a/lib_dec/fd_cng_dec.c b/lib_dec/fd_cng_dec.c
index 974d046368d5d5f31edd11f30bfb2cb0b89946fa..85d82d953c821d3c15c84b3109d6ea458dc20207 100644
--- a/lib_dec/fd_cng_dec.c
+++ b/lib_dec/fd_cng_dec.c
@@ -368,7 +368,7 @@ void deleteFdCngDec(
 
 void ApplyFdCng(
     float *timeDomainInput,
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     float *powerSpectrum,
 #endif
     float **realBuffer, /* i/o: Real part of the buffer */
@@ -384,7 +384,7 @@ void ApplyFdCng(
     int16_t j, k;
     float factor;
     float lsp_cng[M];
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     int16_t L_frame, last_L_frame;
     int32_t sr_core;
 
@@ -419,7 +419,7 @@ void ApplyFdCng(
             /* set noise estimation inactive during concealment, as no update with noise generated by concealment should be performed. */
             /* set noise estimation inactive when we have bit errors, as no update with noise generated by corrupt frame (biterror) should be performed. */
             if ( concealWholeFrame == 0 &&
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                  ( timeDomainInput == NULL ||
                    ( *timeDomainInput<FLT_MAX && * timeDomainInput>( -FLT_MAX ) &&
                      *( timeDomainInput + hFdCngCom->frameSize - 1 ) < FLT_MAX &&
@@ -435,7 +435,7 @@ void ApplyFdCng(
                  ( !st->BER_detect ) )
             {
                 /* Perform noise estimation at the decoder */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 perform_noise_estimation_dec( timeDomainInput, powerSpectrum, hFdCngDec, st->element_mode, st->bwidth, L_frame, last_L_frame, st->last_core_brate, st->VAD );
 #else
                 perform_noise_estimation_dec( timeDomainInput, hFdCngDec, st->element_mode, st->bwidth, st->L_frame, st->last_L_frame, st->last_core_brate, st->VAD );
@@ -471,7 +471,7 @@ void ApplyFdCng(
                     }
                 }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 if ( st->element_mode == IVAS_CPE_MDCT && timeDomainInput == NULL )
                 {
                     st->hTcxDec->CngLevelBackgroundTrace_bfi = sqrtf( sum_f( cngNoiseLevel, hFdCngCom->stopFFTbin - hFdCngCom->startBand ) / NORM_MDCT_FACTOR );
@@ -488,7 +488,7 @@ void ApplyFdCng(
                 if ( hFdCngCom->active_frame_counter > 0 )
                 {
                     /* Perform noise estimation in active frames in the decoder for downward updates */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                     perform_noise_estimation_dec( timeDomainInput, powerSpectrum, hFdCngDec, st->element_mode, st->bwidth, L_frame, last_L_frame, st->last_core_brate, st->VAD );
 #else
                     perform_noise_estimation_dec( timeDomainInput, hFdCngDec, st->element_mode, st->bwidth, st->L_frame, st->last_L_frame, st->last_core_brate, st->VAD );
@@ -496,65 +496,47 @@ void ApplyFdCng(
                 }
             }
 
+#ifndef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             if ( ( concealWholeFrame == 1 ) && ( st->nbLostCmpt == 1 ) && sum_f( cngNoiseLevel + hFdCngCom->startBand, hFdCngCom->stopFFTbin - hFdCngCom->startBand ) > 0.01f )
             {
-#ifndef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
                 /* update lsf cng estimate for concealment. Do that during concealment, in order to avoid addition clean channel complexity*/
                 lpc_from_spectrum( hFdCngCom, hFdCngCom->startBand, hFdCngCom->stopFFTbin, 0 );
 #else
-                if ( st->element_mode == IVAS_CPE_MDCT && st->core != ACELP_CORE )
-                {
-                    float scf[SNS_NPTS];
-                    float scf_int[FDNS_NPTS];
-                    float whitenend_noise_shape[L_FRAME16k];
-                    int16_t inc, start_idx, stop_idx;
-                    float *noiseLevelPtr;
-
-                    wmops_sub_start( "get scfs for bg" );
+            if ( ( concealWholeFrame == 1 ) && ( st->nbLostCmpt == 1 ) )
+            {
+                /* update lsf cng estimate for concealment. Do that during concealment, in order to avoid addition clean channel complexity*/
 
-                    inc = ( st->core > TCX_20 ) ? 2 : 1;
-                    start_idx = hFdCngCom->startBand / inc;
-                    stop_idx = L_frame / inc;
-                    noiseLevelPtr = cngNoiseLevel;
+                /* always set psychParameters for MDCT-Stereo ... */
+                if ( st->element_mode == IVAS_CPE_MDCT && st->hTonalMDCTConc != NULL )
+                {
+                    st->hTonalMDCTConc->psychParams = ( st->core == TCX_20_CORE ) ? &st->hTonalMDCTConc->psychParamsTCX20 : &st->hTonalMDCTConc->psychParamsTCX10;
+                }
 
-                    set_zero( whitenend_noise_shape, start_idx );
-                    for ( j = start_idx; j < stop_idx; j++, noiseLevelPtr += inc )
-                    {
-                        whitenend_noise_shape[j] = *noiseLevelPtr;
-                    }
-                    if ( st->core == TCX_20_CORE )
+                /* ... but do actual computations only if sufficient energy in noise shape */
+                if ( sum_f( cngNoiseLevel + hFdCngCom->startBand, hFdCngCom->stopFFTbin - hFdCngCom->startBand ) > 0.01f )
+                {
+                    if ( st->element_mode == IVAS_CPE_MDCT && st->core != ACELP_CORE )
                     {
-                        st->hTonalMDCTConc->psychParams = &st->hTonalMDCTConc->psychParamsTCX20;
+                        TonalMdctConceal_whiten_noise_shape( st, L_frame, ON_FIRST_LOST_FRAME );
                     }
-                    else
+                    else if ( st->element_mode != IVAS_CPE_MDCT || st->core == ACELP_CORE )
                     {
-                        st->hTonalMDCTConc->psychParams = &st->hTonalMDCTConc->psychParamsTCX10;
+                        lpc_from_spectrum( hFdCngCom, hFdCngCom->startBand, hFdCngCom->stopFFTbin, 0.f );
+                        a2lsp_stab( hFdCngCom->A_cng, lsp_cng, st->lspold_cng );
+                        mvr2r( lsp_cng, st->lspold_cng, M );
+                        lsp2lsf( lsp_cng, st->lsf_cng, M, sr_core );
                     }
-
-                    sns_compute_scf( whitenend_noise_shape, st->hTonalMDCTConc->psychParams, L_frame, scf );
-                    sns_interpolate_scalefactors( scf_int, scf, ENC );
-                    sns_interpolate_scalefactors( st->hTonalMDCTConc->scaleFactorsBackground, scf, DEC );
-                    sns_shape_spectrum( whitenend_noise_shape, st->hTonalMDCTConc->psychParams, scf_int, L_frame );
-
-                    mvr2r( whitenend_noise_shape + start_idx, cngNoiseLevel, stop_idx - start_idx );
-                    wmops_sub_end();
-                }
-                else if ( st->element_mode != IVAS_CPE_MDCT )
-                {
-                    lpc_from_spectrum( hFdCngCom, hFdCngCom->startBand, hFdCngCom->stopFFTbin, 0.f );
-                    a2lsp_stab( hFdCngCom->A_cng, lsp_cng, st->lspold_cng );
-                    mvr2r( lsp_cng, st->lspold_cng, M );
-                    lsp2lsf( lsp_cng, st->lsf_cng, M, sr_core );
+                    st->plcBackgroundNoiseUpdated = 1;
                 }
 #endif
+#ifndef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 
-#ifndef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
                 a2lsp_stab( hFdCngCom->A_cng, lsp_cng, st->lspold_cng );
                 mvr2r( lsp_cng, st->lspold_cng, M );
 
                 lsp2lsf( lsp_cng, st->lsf_cng, M, st->sr_core );
-#endif
                 st->plcBackgroundNoiseUpdated = 1;
+#endif
             }
             break;
 
@@ -567,7 +549,7 @@ void ApplyFdCng(
             if ( st != NULL && st->cng_type == LP_CNG )
             {
                 /* Perform noise estimation on inactive phase at the decoder */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 perform_noise_estimation_dec( timeDomainInput, powerSpectrum, hFdCngDec, st->element_mode, st->bwidth, L_frame, last_L_frame, st->last_core_brate, st->VAD );
 #else
                 perform_noise_estimation_dec( timeDomainInput, hFdCngDec, st->element_mode, st->bwidth, st->L_frame, st->last_L_frame, st->last_core_brate, st->VAD );
@@ -582,7 +564,7 @@ void ApplyFdCng(
                 /* This sets the new CNG levels until a SID update overwrites it */
                 mvr2r( hFdCngDec->bandNoiseShape, cngNoiseLevel, hFdCngCom->stopFFTbin - hFdCngCom->startBand ); /* This sets the new CNG levels until a SID update overwrites it */
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 st->cngTDLevel = (float) sqrt( ( sum_f( cngNoiseLevel, hFdCngCom->stopFFTbin - hFdCngCom->startBand ) / 2 * hFdCngCom->fftlen ) / L_frame );
 #else
                 st->cngTDLevel = (float) sqrt( ( sum_f( cngNoiseLevel, hFdCngCom->stopFFTbin - hFdCngCom->startBand ) / 2 * hFdCngCom->fftlen ) / st->L_frame );
@@ -668,7 +650,7 @@ void ApplyFdCng(
         default:
             break;
     }
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 
     wmops_sub_end();
 #endif
@@ -685,7 +667,7 @@ void ApplyFdCng(
 
 void perform_noise_estimation_dec(
     const float *timeDomainInput,
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     float *power_spectrum,
 #endif
     HANDLE_FD_CNG_DEC hFdCngDec,   /* i/o: FD_CNG structure containing all buffers and variables */
@@ -720,7 +702,7 @@ void perform_noise_estimation_dec(
     float temp, ftemp, delta;
     float wght;
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     if ( !( element_mode == IVAS_CPE_MDCT && power_spectrum != NULL ) )
     {
         /* Perform STFT analysis */
@@ -962,7 +944,7 @@ void perform_noise_estimation_dec(
     }
     else
     {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         if ( element_mode == IVAS_CPE_MDCT && power_spectrum != NULL )
         {
             /* use power spectrum calculated in the MDCT-domain instead of calculating new power spectrum */
diff --git a/lib_dec/igf_dec.c b/lib_dec/igf_dec.c
index 55e526d6654fdd5f5d136597d8efdcc543e7a112..fecc8e96df15820c08b5a8eb524ca86bd96bfc18 100644
--- a/lib_dec/igf_dec.c
+++ b/lib_dec/igf_dec.c
@@ -679,7 +679,12 @@ static void IGF_appl(
     float *pSpectralData,                     /* i/o: Q31 | MDCT spectrum                                  */
     const float *igf_spec,                    /* i  : Q31 | prepared IGF spectrum                          */
     float *virtualSpec,                       /* o  : Q31 | virtual IGF spectrum, used for temp flattening */
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+    int16_t *flag_sparse,                     /* o  : Q0  | temp flattening indicator                      */
+    const int16_t bfi_apply_damping           /* i  : flag to indicate if damping for lost frames should be applied */
+#else
     int16_t *flag_sparse                      /* o  : Q0  | temp flattening indicator                      */
+#endif
 )
 {
     H_IGF_GRID hGrid;
@@ -855,7 +860,11 @@ static void IGF_appl(
     for ( sfb = start_sfb; sfb < stop_sfb; sfb++ )
     {
 
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+        if ( bfi_apply_damping && hPrivateData->frameLossCounter > 0 )
+#else
         if ( hPrivateData->frameLossCounter > 0 )
+#endif
         {
             gain[sfb] = min( gain[sfb], 12.f );
 
@@ -1212,7 +1221,11 @@ void IGFDecApplyMono(
         /* apply IGF in three steps: */
         IGF_prep( hPrivateData, igfGridIdx, hIGFDec->infoTCXNoise, igf_spec, hPrivateData->pSpecFlat, element_mode );
         IGF_calc( hPrivateData, igfGridIdx, spectrum, igf_spec );
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+        IGF_appl( hPrivateData, igfGridIdx, spectrum, igf_spec, hIGFDec->virtualSpec, hIGFDec->flag_sparse, 1 );
+#else
         IGF_appl( hPrivateData, igfGridIdx, spectrum, igf_spec, hIGFDec->virtualSpec, hIGFDec->flag_sparse );
+#endif
     }
 
     /* reset TCX noise indicator vector */
@@ -1238,7 +1251,12 @@ void IGFDecApplyStereo(
     const int16_t igfGridIdx,               /* i  : in case of CELP->TCX switching, use 1.25 framelength */
     const int16_t *coreMsMask,
     const int16_t restrict_hopsize,
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+    const int16_t bfi, /* i  : frame loss == 1, frame good == 0                     */
+    const int16_t bfi_apply_damping
+#else
     const int16_t bfi /* i  : frame loss == 1, frame good == 0                     */
+#endif
 )
 {
     IGF_DEC_PRIVATE_DATA_HANDLE hPrivateDataL, hPrivateDataR;
@@ -1335,8 +1353,13 @@ void IGFDecApplyStereo(
 
         IGF_calc( hPrivateDataL, igfGridIdx, spectrumL, igf_specL );
         IGF_calc( hPrivateDataR, igfGridIdx, spectrumR, igf_specR );
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+        IGF_appl( hPrivateDataL, igfGridIdx, spectrumL, igf_specL, hIGFDecL->virtualSpec, hIGFDecL->flag_sparse, bfi_apply_damping );
+        IGF_appl( hPrivateDataR, igfGridIdx, spectrumR, igf_specR, hIGFDecR->virtualSpec, hIGFDecR->flag_sparse, bfi_apply_damping );
+#else
         IGF_appl( hPrivateDataL, igfGridIdx, spectrumL, igf_specL, hIGFDecL->virtualSpec, hIGFDecL->flag_sparse );
         IGF_appl( hPrivateDataR, igfGridIdx, spectrumR, igf_specR, hIGFDecR->virtualSpec, hIGFDecR->flag_sparse );
+#endif
     }
 
     /* reset TCX noise indicator vector */
@@ -1588,3 +1611,34 @@ void init_igf_dec(
 
     return;
 }
+
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+int16_t get_igf_startline(
+    Decoder_State *st,
+    int16_t L_frame,
+    int16_t L_frameTCX
+)
+{
+    int16_t igf_startline;
+
+    if ( st->igf == 0 )
+    {
+        if ( st->narrowBand == 0 )
+        {
+            /* minimum needed for output with sampling rates lower then the
+               nominal sampling rate */
+            igf_startline = min( L_frameTCX, L_frame );
+        }
+        else
+        {
+            igf_startline = L_frameTCX;
+        }
+    }
+    else
+    {
+        igf_startline = min( st->hIGFDec->infoIGFStartLine, L_frameTCX );
+    }
+
+    return igf_startline;
+}
+#endif
diff --git a/lib_dec/init_dec.c b/lib_dec/init_dec.c
index 40c65d95033f1b55d0536e2ec0fb2420f89300a2..2e31017eaa9fa823b19ee48354b76e58a1428119 100644
--- a/lib_dec/init_dec.c
+++ b/lib_dec/init_dec.c
@@ -54,7 +54,7 @@
 ivas_error init_decoder(
     Decoder_State *st,   /* o  : Decoder static variables structure  */
     const int16_t idchan /* i  : channel ID                          */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const MC_MODE mc_mode /* i  : MC mode                             */
 #endif
@@ -691,7 +691,7 @@ ivas_error init_decoder(
     st->enablePlcWaveadjust = 0;
 
     /* Init Core Decoder */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     open_decoder_LPD( st, st->total_brate, st->last_total_brate, st->bwidth, 0, st->element_mode, 1 );
 #else
     open_decoder_LPD( st, st->total_brate, st->last_total_brate, st->bwidth, 0, 1 );
@@ -714,7 +714,7 @@ ivas_error init_decoder(
      * FD-CNG decoder
      *-----------------------------------------------------------------*/
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     if ( ( st->element_mode == IVAS_CPE_MDCT || idchan == 0 ) && mc_mode != MC_MODE_MCT )
 #else
     if ( idchan == 0 && st->element_mode != IVAS_CPE_MDCT )
diff --git a/lib_dec/ivas_core_dec.c b/lib_dec/ivas_core_dec.c
index de87b4c5577927459ee38dda93879c7a98a9dd41..ad350f4e303b65fe68f533fb564bca9989d9b56d 100644
--- a/lib_dec/ivas_core_dec.c
+++ b/lib_dec/ivas_core_dec.c
@@ -35,7 +35,7 @@
 #ifdef DEBUGGING
 #include "debug.h"
 #endif
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 #include <assert.h>
 #endif
 #include <math.h>
@@ -183,7 +183,7 @@ ivas_error ivas_core_dec(
             st->flagGuidedAcelp = 0;
         }
 
-#ifndef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifndef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         /* PLC: [TCX: Fade-out-recovery] - overlapping part needs to be attenuated for first good frame */
         if ( !st->bfi && st->prev_bfi && ( st->last_core_bfi == TCX_20_CORE || st->last_core_bfi == TCX_10_CORE ) && st->element_mode != IVAS_CPE_MDCT )
         {
@@ -201,7 +201,7 @@ ivas_error ivas_core_dec(
         }
 #else
         /* PLC: [TCX: Fade-out-recovery] - overlapping part needs to be attenuated for first good frame */
-        if ( !st->bfi && st->prev_bfi && ( st->last_core_bfi == TCX_20_CORE || st->last_core_bfi == TCX_10_CORE ) )
+        if ( !st->bfi && st->prev_bfi && ( st->last_core_bfi == TCX_20_CORE || st->last_core_bfi == TCX_10_CORE ) && hMCT == NULL )
         {
             float gain;
             if ( st->hPlcInfo != NULL )
@@ -428,6 +428,21 @@ ivas_error ivas_core_dec(
         {
             updateBuffersForDmxMdctStereo( hCPE, output_frame, output, synth );
         }
+
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+        if ( sts[0]->bfi == 0 && sts[0]->prev_bfi == 1 )
+        {
+            /* On first good frame after frameloss undo the whitening of the bg noise shape */
+            for ( n = 0; n < n_channels; ++n )
+            {
+                if ( sts[n]->last_core_bfi != ACELP_CORE )
+                {
+                    TonalMdctConceal_whiten_noise_shape( sts[n], L_FRAME16k, ON_FIRST_GOOD_FRAME );
+                }
+            }
+        }
+#endif
+
     }
 
     /*---------------------------------------------------------------------*
diff --git a/lib_dec/ivas_cpe_dec.c b/lib_dec/ivas_cpe_dec.c
index d034d08db6cdf2b1a155c5a2b25f00fe7f55eec1..da0911ee5bae74ca2538c15a9df5cc1d1d3c2323 100644
--- a/lib_dec/ivas_cpe_dec.c
+++ b/lib_dec/ivas_cpe_dec.c
@@ -718,7 +718,7 @@ ivas_error create_cpe_dec(
             st->mct_chan_mode = MCT_CHAN_MODE_LFE;
         }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         if ( ( error = init_decoder( st, n, st_ivas->mc_mode ) ) != IVAS_ERR_OK )
 #else
         if ( ( error = init_decoder( st, n ) ) != IVAS_ERR_OK )
diff --git a/lib_dec/ivas_mct_dec_mct.c b/lib_dec/ivas_mct_dec_mct.c
index 00eff03dac152d37204e3626405f79c340a236a5..ec19acb60253b94dcdd3564246ac40ea1cd0cda7 100644
--- a/lib_dec/ivas_mct_dec_mct.c
+++ b/lib_dec/ivas_mct_dec_mct.c
@@ -283,7 +283,11 @@ void mctStereoIGF_dec(
                 /* stereo IGF decoding */
                 assert( ( sts[0]->core == sts[1]->core ) || ( hMCT->hBlockData[b]->hStereoMdct->mdct_stereo_mode[0] == SMDCT_DUAL_MONO ) );
 
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+                decoder_tcx_IGF_stereo( sts, hMCT->hBlockData[b]->hStereoMdct, hMCT->hBlockData[b]->mask, p_x, L_frame[0], left_rect[0], k, bfi, 1 /* <- is_mct */ );
+#else
                 decoder_tcx_IGF_stereo( sts, hMCT->hBlockData[b]->hStereoMdct, hMCT->hBlockData[b]->mask, p_x, L_frame[0], left_rect[0], k, bfi );
+#endif
             }
             else
             {
diff --git a/lib_dec/ivas_mdct_core_dec.c b/lib_dec/ivas_mdct_core_dec.c
index ed5114c651be2c572fe2db046f7128b2af463185..d05024c56599ce49f335e8e547776551a9b40811 100644
--- a/lib_dec/ivas_mdct_core_dec.c
+++ b/lib_dec/ivas_mdct_core_dec.c
@@ -102,7 +102,7 @@ static void dec_prm_tcx_sidebits(
     int16_t p_param[NB_DIV],       /* o  : pointer to parameters for next round of bs reading*/
     int16_t nTnsBitsTCX10[NB_DIV], /* o  : number of TNS bits per TCX10 subframe             */
     Decoder_State *st0,            /* i/o: core decoder state handle - for bitstream         */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const int16_t MCT_flag,
 #endif
     const int16_t ch /* i  : channel                                           */
@@ -134,7 +134,7 @@ static void dec_prm_tcx_sidebits(
      *--------------------------------------------------------------------------------*/
 
     /* Modes (ACE_GC, ACE_UC, TCX20, TCX10...) */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     getTCXMode( st, st0, MCT_flag );
 #else
     getTCXMode( st, st0 );
@@ -381,7 +381,7 @@ void ivas_mdct_dec_side_bits_frame_channel(
                 tmp = 3;
             }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             dec_prm_tcx_sidebits( param[ch], st, ( ( st->element_mode == IVAS_CPE_MDCT && !MCT_flag ) ? sts[0]->hTcxDec->tnsActive : NULL ), p_param[ch], nTnsBitsTCX10[ch], st0, MCT_flag, tmp );
 #else
             dec_prm_tcx_sidebits( param[ch], st, ( ( st->element_mode == IVAS_CPE_MDCT && !MCT_flag ) ? sts[0]->hTcxDec->tnsActive : NULL ), p_param[ch], nTnsBitsTCX10[ch], st0, tmp );
@@ -481,7 +481,7 @@ void ivas_mdct_core_invQ(
     const int16_t *prm_sqQ;
     int16_t L_frameTCX_global[CPE_CHANNELS];
     float tmp_ms_sig[CPE_CHANNELS][N_MAX];
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     float concealment_noise[CPE_CHANNELS][L_FRAME48k];
     TONALMDCTCONC_NOISE_GEN_MODE noise_gen_mode_bfi;
 #endif
@@ -490,7 +490,7 @@ void ivas_mdct_core_invQ(
 
     sts = hCPE->hCoreCoder;
     bfi = sts[0]->bfi;
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     noise_gen_mode_bfi = -1;
 #endif
 
@@ -514,7 +514,7 @@ void ivas_mdct_core_invQ(
                             sts[0]->core, sts[1]->core, sts[0]->igf, L_frameTCX[0], 0, sts[0]->last_core, sts[1]->last_core, 1 );
     }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     if ( bfi )
     {
         if ( sts[0]->core == sts[1]->core )
@@ -728,15 +728,11 @@ void ivas_mdct_core_invQ(
                 }
                 nf_seed = 0;
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-                decoder_tcx_invQ( st, prm[ch], Aq[ch], Aind[ch], L_spec[ch], L_frame[ch], L_frameTCX[ch], x[ch][k], NULL, xn_buf, &fUseTns[ch][k], &tnsData[ch][k], &gain_tcx, &prm_sqQ, &nf_seed, bfi, isMCT, k );
-#else
                 decoder_tcx_invQ( st, prm[ch], Aq[ch], Aind[ch], L_spec[ch], L_frame[ch], L_frameTCX[ch], x[ch][k], NULL, xn_buf, &fUseTns[ch][k], &tnsData[ch][k], &gain_tcx, &prm_sqQ, &nf_seed, bfi, k );
-#endif
 
                 mvr2r( x[ch][k], x_0[ch][k], L_frameTCX[ch] );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 if ( bfi && !isMCT )
                 {
                     TonalMdctConceal_create_concealment_noise( concealment_noise[ch], hCPE, L_frameTCX[ch], L_frame[ch], ch, k, st->core, st->hTcxDec->cummulative_damping_tcx, noise_gen_mode_bfi );
@@ -861,7 +857,7 @@ void ivas_mdct_core_reconstruct(
                 TonalMDCTConceal_SaveTimeSignal( st->hTonalMDCTConc, synthFB, L_frameTCX[ch] );
             }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             decoder_tcx_post( st, synth, synthFB, NULL, bfi, isMCT );
 #else
             decoder_tcx_post( st, synth, synthFB, NULL, bfi );
@@ -873,7 +869,7 @@ void ivas_mdct_core_reconstruct(
             /* PLC: [TCX: TD PLC] */
             if ( isMCT )
             {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 con_tcx( st, &synthFB[0], -1.f, NULL, 0, NULL );
 #else
                 con_tcx( st, &synthFB[0], -1.f, NULL, 0 );
@@ -881,7 +877,7 @@ void ivas_mdct_core_reconstruct(
             }
             else
             {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 con_tcx( st, &synthFB[0], hCPE->hStereoMdct->lastCoh, &sts[0]->seed_acelp, ( sts[1]->core != ACELP_CORE ) ? 1 : 0, &st->hFdCngDec->hFdCngCom->A_cng[0] );
 #else
                 con_tcx( st, &synthFB[0], hCPE->hStereoMdct->lastCoh, &sts[0]->seed_acelp, ( sts[1]->core != ACELP_CORE ) ? 1 : 0 );
@@ -1064,34 +1060,14 @@ void ivas_mdct_core_tns_ns(
             {
                 sns_interpolate_scalefactors( &sns_int_scf[0], &Aq[ch][k * M], DEC );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 if ( isMCT && st->hTonalMDCTConc != NULL && ( ( k + 1 ) == nSubframes[ch] ) )
 #else
                 if ( isMCT && st->hTonalMDCTConc != NULL )
 #endif
                 {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-                    int16_t infoIGFStartLine;
-
-                    if ( st->igf == 0 )
-                    {
-                        if ( st->narrowBand == 0 )
-                        {
-                            /* minimum needed for output with sampling rates lower then the
-                            nominal sampling rate */
-                            infoIGFStartLine = min( L_frameTCX[ch], L_frame[ch] );
-                        }
-                        else
-                        {
-                            infoIGFStartLine = L_frameTCX[ch];
-                        }
-                    }
-                    else
-                    {
-                        infoIGFStartLine = min( st->hIGFDec->infoIGFStartLine, L_frameTCX[ch] );
-                    }
-
-                    TonalMDCTConceal_SaveFreqSignal( st->hTonalMDCTConc, x[ch][k], L_frameTCX[ch], L_frame[ch], &sns_int_scf[0], infoIGFStartLine );
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+                    TonalMDCTConceal_SaveFreqSignal( st->hTonalMDCTConc, x[ch][k], L_frameTCX[ch], L_frame[ch], &sns_int_scf[0], get_igf_startline( st, L_frame[ch], L_frameTCX[ch] ) );
 #else
                     TonalMDCTConceal_SaveFreqSignal( st->hTonalMDCTConc, x[ch][k], L_frameTCX[ch], L_frame[ch], &sns_int_scf[0] );
 #endif
@@ -1101,17 +1077,18 @@ void ivas_mdct_core_tns_ns(
             {
                 if ( st->hTonalMDCTConc != NULL )
                 {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-                    if ( st->hTcxDec->cummulative_damping_tcx != 1.f )
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+                    if ( !isMCT && st->hTcxDec->cummulative_damping_tcx != 1.f )
                     {
-                        float *scf_last;
-                        float *scf_bg;
-                        float fade_in;
-                        float fade_out;
+                        float *scf_last, *scf_bg;
+                        float fade_in, fade_out;
 
                         scf_last = &st->hTonalMDCTConc->lastBlockData.scaleFactors[0];
                         scf_bg = &st->hTonalMDCTConc->scaleFactorsBackground[0];
-                        fade_out = st->hTcxDec->cummulative_damping_tcx;
+
+                        st->hTonalMDCTConc->scf_fadeout *= 0.95f;
+
+                        fade_out = st->hTonalMDCTConc->scf_fadeout;
                         fade_in = 1 - fade_out;
 
                         for ( int16_t i = 0; i < st->hTonalMDCTConc->nScaleFactors; i++ )
@@ -1121,6 +1098,7 @@ void ivas_mdct_core_tns_ns(
                     }
                     else
                     {
+                        st->hTonalMDCTConc->scf_fadeout = 1.0f;
                         mvr2r( st->hTonalMDCTConc->lastBlockData.scaleFactors, &sns_int_scf[0], st->hTonalMDCTConc->nScaleFactors );
                     }
 #else
diff --git a/lib_dec/ivas_sce_dec.c b/lib_dec/ivas_sce_dec.c
index b3a73706df11a9f1d72428aae1e7bcf4852cb34f..b24d60505b7f57be4f92f3aa00f9943366b85909 100644
--- a/lib_dec/ivas_sce_dec.c
+++ b/lib_dec/ivas_sce_dec.c
@@ -350,7 +350,7 @@ ivas_error create_sce_dec(
     st->total_brate = hSCE->element_brate; /* dummy initialization for getting right pointers initialization of input buffers in init_coder_ace_plus() */
     st->mct_chan_mode = MCT_CHAN_MODE_REGULAR;
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     if ( ( error = init_decoder( st, 0, st_ivas->mc_mode ) ) != IVAS_ERR_OK )
 #else
     if ( ( error = init_decoder( st, 0 ) ) != IVAS_ERR_OK )
diff --git a/lib_dec/ivas_stat_dec.h b/lib_dec/ivas_stat_dec.h
index c773491d410632dc6dfa382db42b70b181d4d913..e5195cba5a74a1b3a7c1765c9f03eb0e7fbc9b2e 100644
--- a/lib_dec/ivas_stat_dec.h
+++ b/lib_dec/ivas_stat_dec.h
@@ -320,7 +320,7 @@ typedef struct stereo_mdct_dec_data_structure
 
     int16_t prev_ms_mask[NB_DIV][MAX_SFB];
     float lastCoh;
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     int16_t noise_seeds_channels[CPE_CHANNELS];
     int16_t noise_seed_common;
 #endif
diff --git a/lib_dec/ivas_stereo_mdct_core_dec.c b/lib_dec/ivas_stereo_mdct_core_dec.c
index 32e9fe103cf66de8b24de30b7cbc1705faaf8232..beb121a1fc207994816a424cf3329a3360ae6563 100644
--- a/lib_dec/ivas_stereo_mdct_core_dec.c
+++ b/lib_dec/ivas_stereo_mdct_core_dec.c
@@ -50,7 +50,7 @@
  *-------------------------------------------------------------------------*/
 
 static void apply_dmx_weights( CPE_DEC_HANDLE hCPE, float *x[CPE_CHANNELS][NB_DIV], int16_t transform_type_left[NB_DIV], int16_t transform_type_right[NB_DIV] );
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 static void run_min_stats( Decoder_State **sts, float *x[CPE_CHANNELS][NB_DIV] );
 #endif
 
@@ -301,7 +301,11 @@ void stereo_mdct_core_dec(
                     assert( ( sts[0]->core == sts[1]->core ) || ( hCPE->hStereoMdct->mdct_stereo_mode[0] == SMDCT_DUAL_MONO ) );
 
                     /* stereo IGF decoding */
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+                    decoder_tcx_IGF_stereo( sts, hCPE->hStereoMdct, ms_mask, x, L_frame[0], left_rect[0], k, bfi, 0 /* <- is_mct */ );
+#else
                     decoder_tcx_IGF_stereo( sts, hCPE->hStereoMdct, ms_mask, x, L_frame[0], left_rect[0], k, bfi );
+#endif
                 }
                 else
                 {
@@ -331,34 +335,14 @@ void stereo_mdct_core_dec(
 
                 sns_interpolate_scalefactors( &sns_int_scf[0], &Aq[ch][k * M], DEC );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 if ( st->hTonalMDCTConc != NULL && ( ( k + 1 ) == nSubframes[ch] ) )
 #else
                 if ( st->hTonalMDCTConc != NULL )
 #endif
                 {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
-                    int16_t infoIGFStartLine;
-
-                    if ( st->igf == 0 )
-                    {
-                        if ( st->narrowBand == 0 )
-                        {
-                            /* minimum needed for output with sampling rates lower then the
-                            nominal sampling rate */
-                            infoIGFStartLine = min( L_frameTCX[ch], L_frame[ch] );
-                        }
-                        else
-                        {
-                            infoIGFStartLine = L_frameTCX[ch];
-                        }
-                    }
-                    else
-                    {
-                        infoIGFStartLine = min( st->hIGFDec->infoIGFStartLine, L_frameTCX[ch] );
-                    }
-
-                    TonalMDCTConceal_SaveFreqSignal( st->hTonalMDCTConc, x[ch][k], L_frameTCX[ch], L_frame[ch], &sns_int_scf[0], infoIGFStartLine );
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+                    TonalMDCTConceal_SaveFreqSignal( st->hTonalMDCTConc, x[ch][k], L_frameTCX[ch], L_frame[ch], &sns_int_scf[0], get_igf_startline( st, L_frame[ch], L_frameTCX[ch] ) );
 #else
                     TonalMDCTConceal_SaveFreqSignal( st->hTonalMDCTConc, x[ch][k], L_frameTCX[ch], L_frame[ch], &sns_int_scf[0] );
 #endif
@@ -388,7 +372,7 @@ void stereo_mdct_core_dec(
         ivas_ls_setup_conversion_process_mdct_param_mc( st_ivas, x );
     }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     run_min_stats( sts, x );
 #endif
 
@@ -609,7 +593,7 @@ static void apply_dmx_weights(
     return;
 }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 /*-------------------------------------------------------------------*
  * run_min_stats()
  *
diff --git a/lib_dec/ivas_stereo_switching_dec.c b/lib_dec/ivas_stereo_switching_dec.c
index 80736dd425c13b05baa2fb0d917bd32095faec12..2e32b8e85a496b20b65fea28599b6b473fbef0e0 100644
--- a/lib_dec/ivas_stereo_switching_dec.c
+++ b/lib_dec/ivas_stereo_switching_dec.c
@@ -424,7 +424,7 @@ ivas_error stereo_memory_dec(
             if ( hCPE->last_element_mode == IVAS_CPE_MDCT )
             {
                 cpy_tcx_ltp_data( hCPE->hCoreCoder[1]->hTcxLtpDec, hCPE->hStereoDft->hTcxLtpDec, output_Fs );
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 deleteFdCngDec( &hCPE->hCoreCoder[1]->hFdCngDec );
 #endif
             }
@@ -489,7 +489,7 @@ ivas_error stereo_memory_dec(
             /* deallocated TCX/IGF structures for second channel */
             deallocate_CoreCoder_TCX( hCPE->hCoreCoder[1] );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             if ( hCPE->last_element_mode == IVAS_CPE_MDCT )
             {
                 deleteFdCngDec( &hCPE->hCoreCoder[1]->hFdCngDec );
@@ -675,7 +675,7 @@ ivas_error stereo_memory_dec(
                 /* deallocate core-decoder substructures */
                 deallocate_CoreCoder( st );
 
-#ifndef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifndef MDCT_STEREO_PLC_FADE_2_BG_NOISE
                 /* deallocate FD_CNG substructure */
                 deleteFdCngDec( &st->hFdCngDec );
 #endif
@@ -702,7 +702,7 @@ ivas_error stereo_memory_dec(
                 }
             }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             /* allocate Fd-Cng structure for second channel */
             if ( ( error = createFdCngDec( &st->hFdCngDec ) ) != IVAS_ERR_OK )
             {
diff --git a/lib_dec/ivas_tcx_core_dec.c b/lib_dec/ivas_tcx_core_dec.c
index e3462f21bc23a0324b7251bd7b18457b728955d2..e46c32ddbbfde5dc0860c95b5e147de28f1b7480 100644
--- a/lib_dec/ivas_tcx_core_dec.c
+++ b/lib_dec/ivas_tcx_core_dec.c
@@ -150,7 +150,7 @@ void stereo_tcx_init_dec(
         }
 
         /* Reconfigure Core */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         mode_switch_decoder_LPD( st, st->bwidth, st->bits_frame_nominal * FRAMES_PER_SEC, st->last_bits_frame_nominal * FRAMES_PER_SEC, frame_size_index, is_mct, last_element_mode );
 #else
         mode_switch_decoder_LPD( st, st->bwidth, st->bits_frame_nominal * FRAMES_PER_SEC, st->last_bits_frame_nominal * FRAMES_PER_SEC, frame_size_index, is_mct );
@@ -457,7 +457,7 @@ void stereo_tcx_core_dec(
         }
 
         /* PLC: [TCX: TD PLC] */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         con_tcx( st, &synthFB[0], -1.f, NULL, 0, NULL );
 #else
         con_tcx( st, &synthFB[0], -1.f, NULL, 0 );
@@ -589,7 +589,7 @@ void stereo_tcx_core_dec(
             TonalMDCTConceal_SaveTimeSignal( st->hTonalMDCTConc, synthFB, hTcxDec->L_frameTCX );
         }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         decoder_tcx_post( st, synth, synthFB, Aq, bfi, 0 );
 #else
         decoder_tcx_post( st, synth, synthFB, Aq, bfi );
@@ -750,7 +750,7 @@ void stereo_tcx_core_dec(
 
         if ( st->element_mode != IVAS_CPE_TD )
         {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             ApplyFdCng( signal_out, NULL, NULL, NULL, st, st->bfi, 0 );
 #else
             ApplyFdCng( signal_out, NULL, NULL, st, st->bfi, 0 );
@@ -779,7 +779,7 @@ void stereo_tcx_core_dec(
 
         if ( st->element_mode == IVAS_CPE_TD && st->idchan == 0 )
         {
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
             ApplyFdCng( signal_out, NULL, NULL, NULL, st, st->bfi, 0 );
 #else
             ApplyFdCng( signal_out, NULL, NULL, st, st->bfi, 0 );
@@ -867,7 +867,7 @@ static void dec_prm_tcx(
      *--------------------------------------------------------------------------------*/
 
     /* Modes (ACE_GC, ACE_UC, TCX20, TCX10...) */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     getTCXMode( st, st, 0 /* <- MCT_flag */ );
 #else
     getTCXMode( st, st );
diff --git a/lib_dec/stat_dec.h b/lib_dec/stat_dec.h
index 8fc8ec5282be03a3345c9c83ff5b20c14c645c61..0c7a836cb43a86a1fc0845635f2ac4af43abddcd 100644
--- a/lib_dec/stat_dec.h
+++ b/lib_dec/stat_dec.h
@@ -204,15 +204,16 @@ typedef struct
     Float32 *secondLastPcmOut;
     float *secondLastPowerSpectrum;
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     float scaleFactorsBackground[FDNS_NPTS];
+    float scf_fadeout;
     PsychoacousticParameters *psychParams;
-    /* could be stored only once, since the same for all channels (always at 16Khz fs) */
     PsychoacousticParameters psychParamsTCX20;
     PsychoacousticParameters psychParamsTCX10;
 
     float last_block_nrg;
     float curr_noise_nrg;
+    float faded_signal_nrg;
 #endif
 
     float nFramesLost;
diff --git a/lib_dec/tonalMDCTconcealment.c b/lib_dec/tonalMDCTconcealment.c
index b43f85b8f9d51e2979a620c735bbc33aee51d09a..872cf1efa937ae1a6c65f362f338efb30ebc2027 100644
--- a/lib_dec/tonalMDCTconcealment.c
+++ b/lib_dec/tonalMDCTconcealment.c
@@ -93,14 +93,16 @@ ivas_error TonalMDCTConceal_Init(
     hTonalMDCTConc->nSamplesCore = nSamplesCore;
     hTonalMDCTConc->nScaleFactors = nScaleFactors;
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     set_zero( hTonalMDCTConc->scaleFactorsBackground, FDNS_NPTS );
+    hTonalMDCTConc->scf_fadeout = 1.0f;
     PsychoacousticParameters_Init( INT_FS_16k, L_FRAME16k, 64, 1, 1, &hTonalMDCTConc->psychParamsTCX20 );
     PsychoacousticParameters_Init( INT_FS_16k, L_FRAME16k / 2, 64, 0, 1, &hTonalMDCTConc->psychParamsTCX10 );
     hTonalMDCTConc->psychParams = NULL;
 
     hTonalMDCTConc->last_block_nrg = 0.0f;
     hTonalMDCTConc->curr_noise_nrg = 0.0f;
+    hTonalMDCTConc->faded_signal_nrg = 0.0f;
 #endif
 
     /* Offset the pointer to the end of buffer, so that pTCI is not destroyed when
@@ -123,7 +125,7 @@ void TonalMDCTConceal_SaveFreqSignal(
     const uint16_t nNewSamples,
     const uint16_t nNewSamplesCore,
     const float *scaleFactors
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     ,
     const int16_t infoIGFStartLine
 #endif
@@ -168,7 +170,7 @@ void TonalMDCTConceal_SaveFreqSignal(
     if ( ( nNewSamples > 0 ) && ( nNewSamples <= 2 * L_FRAME_MAX ) )
     {
         /* Store new data */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         int16_t i;
 
         hTonalMDCTConc->last_block_nrg = 0.0f;
@@ -500,8 +502,9 @@ void TonalMDCTConceal_InsertNoise(
     int16_t *pSeed,
     const float tiltCompFactor,
     const float crossfadeGain,
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const float concealment_noise[L_FRAME48k],
+    const float cngLevelBackgroundTrace_bfi,
 #endif
     const int16_t crossOverFreq )
 {
@@ -509,11 +512,18 @@ void TonalMDCTConceal_InsertNoise(
     float x, y;
     Word16 rnd;
     float g, nrgNoiseInLastFrame, nrgWhiteNoise, tiltFactor, tilt;
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+    float last_block_nrg_correct;
+#endif
 
     wmops_sub_start( "InsertNoise" );
 
     g = 1.0f - crossfadeGain;
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
+    if ( !hTonalMDCTConc->lastBlockData.blockIsConcealed )
+#else
     if ( !hTonalMDCTConc->lastBlockData.blockIsConcealed )
+#endif
     {
         rnd = 1977;
     }
@@ -522,13 +532,15 @@ void TonalMDCTConceal_InsertNoise(
         rnd = *pSeed;
     }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     /* based on what is done in tcx_noise_filling() */
     /* always initialize these to avoid compiler warnings */
     tiltFactor = (float) pow( max( 0.375f, tiltCompFactor ), 1.0f / hTonalMDCTConc->lastBlockData.nSamples );
     tilt = 1.0f;
     nrgNoiseInLastFrame = 0.0f;
     nrgWhiteNoise = 0.0f;
+    hTonalMDCTConc->faded_signal_nrg = 0.0f;
+    last_block_nrg_correct = 0.0f;
 #endif
 
     if ( !hTonalMDCTConc->lastBlockData.blockIsValid )
@@ -536,7 +548,7 @@ void TonalMDCTConceal_InsertNoise(
         /* may just become active if the very first frame is lost */
         set_f( mdctSpectrum, 0.0f, hTonalMDCTConc->nSamples );
     }
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     else if ( concealment_noise != NULL )
     {
         if ( !tonalConcealmentActive )
@@ -564,7 +576,7 @@ void TonalMDCTConceal_InsertNoise(
             /* actual fadeout is done in this case */
             else
             {
-                g *= (float) sqrt( hTonalMDCTConc->last_block_nrg / hTonalMDCTConc->curr_noise_nrg );
+                g *= (float) sqrt( cngLevelBackgroundTrace_bfi / hTonalMDCTConc->curr_noise_nrg );
 
                 for ( i = 0; i < crossOverFreq; i++ )
                 {
@@ -579,6 +591,8 @@ void TonalMDCTConceal_InsertNoise(
                     {
                         mdctSpectrum[i] = g * y - crossfadeGain * x;
                     }
+
+                    hTonalMDCTConc->faded_signal_nrg += mdctSpectrum[i] * mdctSpectrum[i];
                 }
                 for ( l = crossOverFreq; l < hTonalMDCTConc->lastBlockData.nSamples; l++ )
                 {
@@ -599,6 +613,11 @@ void TonalMDCTConceal_InsertNoise(
                 for ( l = hTonalMDCTConc->pTCI->lowerIndex[i]; l <= hTonalMDCTConc->pTCI->upperIndex[i]; l++ )
                 {
                     mdctSpectrum[l] = 0;
+                    if ( l < crossOverFreq )
+                    {
+                        last_block_nrg_correct += hTonalMDCTConc->lastBlockData.spectralData[l] * hTonalMDCTConc->lastBlockData.spectralData[l];
+                        hTonalMDCTConc->curr_noise_nrg -= concealment_noise[l] * concealment_noise[l];
+                    } 
                 }
             }
 
@@ -651,7 +670,7 @@ void TonalMDCTConceal_InsertNoise(
             /* actual fadeout is done in this case */
             else
             {
-                g *= (float) sqrt( hTonalMDCTConc->last_block_nrg / hTonalMDCTConc->curr_noise_nrg );
+                g *= (float) sqrt( cngLevelBackgroundTrace_bfi / hTonalMDCTConc->curr_noise_nrg );
 
                 for ( l = 0; l < hTonalMDCTConc->pTCI->lowerIndex[0]; l++ )
                 {
@@ -666,6 +685,7 @@ void TonalMDCTConceal_InsertNoise(
                     {
                         mdctSpectrum[l] = g * y - crossfadeGain * x;
                     }
+                    hTonalMDCTConc->faded_signal_nrg += mdctSpectrum[l] * mdctSpectrum[l];
                 }
                 for ( i = 1; i < hTonalMDCTConc->pTCI->numIndexes; i++ )
                 {
@@ -682,6 +702,7 @@ void TonalMDCTConceal_InsertNoise(
                         {
                             mdctSpectrum[l] = g * y - crossfadeGain * x;
                         }
+                        hTonalMDCTConc->faded_signal_nrg += mdctSpectrum[l] * mdctSpectrum[l];
                     }
                 }
 
@@ -698,6 +719,7 @@ void TonalMDCTConceal_InsertNoise(
                     {
                         mdctSpectrum[l] = g * y - crossfadeGain * x;
                     }
+                    hTonalMDCTConc->faded_signal_nrg += mdctSpectrum[l] * mdctSpectrum[l];
                 }
 
                 for ( l = crossOverFreq; l < hTonalMDCTConc->lastBlockData.nSamples; l++ )
@@ -706,11 +728,19 @@ void TonalMDCTConceal_InsertNoise(
                 }
             }
         }
+
+        if ( hTonalMDCTConc->faded_signal_nrg > 0.0f && hTonalMDCTConc->curr_noise_nrg > MDCT_ST_PLC_FADEOUT_MIN_NOISE_NRG )
+        {
+            float nrg_corr_factor;
+            
+            nrg_corr_factor = sqrtf( ( hTonalMDCTConc->last_block_nrg - last_block_nrg_correct ) / hTonalMDCTConc->faded_signal_nrg );
+            v_multc( mdctSpectrum, nrg_corr_factor, mdctSpectrum, crossOverFreq );
+        }
     }
 #endif
     else
     {
-#ifndef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifndef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         /* based on what is done in tcx_noise_filling() */
         tiltFactor = (float) pow( max( 0.375f, tiltCompFactor ), 1.0f / hTonalMDCTConc->lastBlockData.nSamples );
         tilt = 1.0f;
@@ -962,7 +992,7 @@ void TonalMDCTConceal_SaveTimeSignal(
     return;
 }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 void TonalMdctConceal_create_concealment_noise(
     float concealment_noise[L_FRAME48k],
     CPE_DEC_HANDLE hCPE,
@@ -1049,7 +1079,6 @@ void TonalMdctConceal_create_concealment_noise(
     c_inv = sqrtf( 1 - hStereoMdct->lastCoh );
 
     /* pre-compute the noise shape for later weighting of the noise spectra */
-    /* TODO: optimize by intertwining with later loop */
     cngNoiseLevelPtr = &hFdCngCom->cngNoiseLevel[0];
     inc = ( st->core > TCX_20_CORE ) ? 2 : 1;
     start_idx = hFdCngCom->startBand / inc;
@@ -1072,7 +1101,7 @@ void TonalMdctConceal_create_concealment_noise(
     }
 
     /* fill the noise vector */
-    hTonalMDCTConc->curr_noise_nrg = 0.001f;
+    hTonalMDCTConc->curr_noise_nrg = MDCT_ST_PLC_FADEOUT_MIN_NOISE_NRG;
     if ( noise_gen_mode == EQUAL_CORES || ( ( noise_gen_mode == TCX20_IN_0_TCX10_IN_1 && idchan == 0 ) || ( noise_gen_mode == TCX10_IN_0_TCX20_IN_1 && idchan == 1 ) ) )
     {
         /* current channel is TCX20 -> generate noise for "full-length" spectrum */
@@ -1100,6 +1129,14 @@ void TonalMdctConceal_create_concealment_noise(
         }
     }
 
+    if ( st->tonal_mdct_plc_active )
+    {
+        for ( i = crossOverFreq; i < max( crossOverFreq, hTonalMDCTConc->pTCI->lowerIndex[hTonalMDCTConc->pTCI->numIndexes - 1] ); ++i )
+        {
+            concealment_noise[i] *= 0.0f;
+        }
+    }
+
     /* restore common seed
          - after finishing the first channel
          - after a first subframe if the current channel is TCX10 */
@@ -1108,8 +1145,68 @@ void TonalMdctConceal_create_concealment_noise(
         *rnd_c = save_rnd_c;
     }
 
+    st->seed_tcx_plc = *rnd;
+
     wmops_sub_end();
 
     return;
 }
+
+void TonalMdctConceal_whiten_noise_shape(
+    Decoder_State *st,
+    const int16_t L_frame,
+    const TONALMDCTCONC_NOISE_SHAPE_WHITENING_MODE whitening_mode
+)
+{
+    int16_t inc, start_idx, stop_idx;
+    float *noiseLevelPtr, *scfs_bg, *scfs_for_shaping;
+    HANDLE_FD_CNG_COM hFdCngCom;
+    float whitenend_noise_shape[L_FRAME16k];
+    float scfs_int[FDNS_NPTS];
+    const PsychoacousticParameters *psychParams;
+
+    wmops_sub_start( "apply_sns_on_noise_shape" );
+
+    scfs_bg = &st->hTonalMDCTConc->scaleFactorsBackground[0];
+    psychParams = st->hTonalMDCTConc->psychParams;
+    hFdCngCom = st->hFdCngDec->hFdCngCom;
+
+    inc = ( ( whitening_mode == ON_FIRST_LOST_FRAME ? st->core : st->last_core ) > TCX_20_CORE ) ? 2 : 1;
+    start_idx = hFdCngCom->startBand / inc;
+    stop_idx = L_frame / inc;
+    noiseLevelPtr = hFdCngCom->cngNoiseLevel;
+
+    set_zero( whitenend_noise_shape, start_idx );
+    for ( int16_t j = start_idx; j < stop_idx; j++, noiseLevelPtr += inc )
+    {
+        whitenend_noise_shape[j] = *noiseLevelPtr;
+    }
+
+    if ( whitening_mode == ON_FIRST_LOST_FRAME )
+    {
+        float scf[SNS_NPTS];
+
+        sns_compute_scf( whitenend_noise_shape, psychParams, L_frame, scf );
+        sns_interpolate_scalefactors( scfs_int, scf, ENC );
+        sns_interpolate_scalefactors( scfs_bg, scf, DEC );
+        scfs_for_shaping = &scfs_int[0];
+    }
+    else if ( whitening_mode == ON_FIRST_GOOD_FRAME )
+    {
+        scfs_for_shaping = &scfs_bg[0];
+    }
+
+    if ( sum_f( scfs_for_shaping, FDNS_NPTS ) > 0.0f )
+    {
+        sns_shape_spectrum( whitenend_noise_shape, psychParams, scfs_for_shaping, L_frame );
+        mvr2r( whitenend_noise_shape + start_idx, hFdCngCom->cngNoiseLevel, stop_idx - start_idx );
+    }
+    else
+    {
+        set_zero( hFdCngCom->cngNoiseLevel, stop_idx - start_idx );
+    }
+
+    wmops_sub_end();
+}
+
 #endif
diff --git a/lib_enc/enc_prm.c b/lib_enc/enc_prm.c
index 062069ceeef99bd821d9e1458568334ebed13656..33c9d6fc7b6dfd7851cdae1dc1831c105e57bffb 100644
--- a/lib_enc/enc_prm.c
+++ b/lib_enc/enc_prm.c
@@ -55,7 +55,7 @@
 void writeTCXMode(
     Encoder_State *st,     /* i/o: encoder state structure       */
     BSTR_ENC_HANDLE hBstr, /* i/o: bitstream handle              */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const int16_t is_mct,
 #endif
     int16_t *nbits_start /* o  : nbits start                   */
@@ -88,7 +88,7 @@ void writeTCXMode(
 
         push_next_indice( hBstr, index, 2 );
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         if ( st->element_mode == IVAS_CPE_MDCT && !is_mct )
         {
             push_next_indice( hBstr, st->vad_flag, 1 );
@@ -792,7 +792,7 @@ void enc_prm(
 
     /* EVS header */
     /* Modes (ACE_GC, ACE_UC, TCX20, TCX10...) */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     writeTCXMode( st, st->hBstr, 0, /* <- is_mct */ &nbits_start );
 #else
     writeTCXMode( st, st->hBstr, &nbits_start );
diff --git a/lib_enc/ivas_mdct_core_enc.c b/lib_enc/ivas_mdct_core_enc.c
index 4d9d1f257780ba86b07286d2b5b59c0b6bde895b..0d2f5817d6dbf1da5ab7c2376b27b94131e0db37 100644
--- a/lib_enc/ivas_mdct_core_enc.c
+++ b/lib_enc/ivas_mdct_core_enc.c
@@ -63,7 +63,7 @@ static void enc_prm_pre_mdct(
     int16_t param[],             /* i  : parameters                                         */
     const int16_t *no_param_tns, /* i  : number of TNS parameters per subframe              */
     int16_t p_param[2],          /* o  : pointer to parameters for next round of bs writing */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     const int16_t is_mct,
 #endif
     BSTR_ENC_HANDLE hBstr /* i/o: encoder bitstream handle                           */
@@ -80,7 +80,7 @@ static void enc_prm_pre_mdct(
      * Header
      *--------------------------------------------------------------------------------*/
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     writeTCXMode( st, hBstr, is_mct, &nbits_start );
 #else
     writeTCXMode( st, hBstr, &nbits_start );
@@ -1065,7 +1065,7 @@ void ivas_mdct_core_whitening_enc(
             continue;
         }
 
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
         enc_prm_pre_mdct( st, param_core[ch], ( ( ( ch > 0 ) && ( sts[0]->hTcxEnc->fUseTns[0] + sts[0]->hTcxEnc->fUseTns[1] > 0 ) && !mct_on ) ? tnsSize[ch] : NULL ), p_param[ch], mct_on, hBstr );
 #else
         enc_prm_pre_mdct( st, param_core[ch], ( ( ( ch > 0 ) && ( sts[0]->hTcxEnc->fUseTns[0] + sts[0]->hTcxEnc->fUseTns[1] > 0 ) && !mct_on ) ? tnsSize[ch] : NULL ), p_param[ch], hBstr );
diff --git a/lib_enc/ivas_sns_enc.c b/lib_enc/ivas_sns_enc.c
index 1aeac19c571d46400258a5d66c564f5e4cf68711..87019b8d91334818db5667102d317d45a0b8811e 100644
--- a/lib_enc/ivas_sns_enc.c
+++ b/lib_enc/ivas_sns_enc.c
@@ -43,7 +43,7 @@
 #endif
 #include "wmops.h"
 
-#ifndef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifndef MDCT_STEREO_PLC_FADE_2_BG_NOISE
 #define SNS_NPTS 16 /* Number of downsampled SNS parameters */
 
 /*-------------------------------------------------------------------
diff --git a/lib_enc/ivas_tcx_core_enc.c b/lib_enc/ivas_tcx_core_enc.c
index 79bb2f04a7f02ee103bfe2f8a04bf5f0be23f838..ce2d74ec9a689f1ef59657fc0180741b6ab6ce13 100644
--- a/lib_enc/ivas_tcx_core_enc.c
+++ b/lib_enc/ivas_tcx_core_enc.c
@@ -268,7 +268,7 @@ void stereo_tcx_core_enc(
      *--------------------------------------------------------------------------------*/
 
     /* TCX20/TCX10 and coder type */
-#ifdef FIX_IVAS_185_MDCT_ST_PLC_FADEOUT
+#ifdef MDCT_STEREO_PLC_FADE_2_BG_NOISE
     writeTCXMode( st, hBstr, 0, /* <- is_mct */ &nbits_start );
 #else
     writeTCXMode( st, hBstr, &nbits_start );
diff --git a/scripts/pyaudio3dtools/audiofile.py b/scripts/pyaudio3dtools/audiofile.py
index b03b472ae908aa3d57269d3b9fede4167deb3eeb..46bb452082c7d8a0cca04875bc5bca1dd399ccdf 100755
--- a/scripts/pyaudio3dtools/audiofile.py
+++ b/scripts/pyaudio3dtools/audiofile.py
@@ -35,7 +35,6 @@ import platform
 import shutil
 import struct
 import subprocess as sp
-import warnings
 from importlib import import_module
 from tempfile import TemporaryDirectory
 from typing import Optional, Tuple
@@ -74,18 +73,6 @@ def readfile(
 
     if file_extension == ".wav":
         fs, data = wav.read(filename)
-        if data.dtype == np.int32:
-            data = np.interp(
-                data,
-                (np.iinfo(np.int32).min, np.iinfo(np.int32).max),
-                (np.iinfo(np.int16).min, np.iinfo(np.int16).max),
-            )
-        elif data.dtype == np.float32:
-            data = np.interp(
-                data,
-                (-1, 1),
-                (np.iinfo(np.int16).min, np.iinfo(np.int16).max),
-            )
         x = np.array(data, dtype=outdtype)
         file_len = x.shape[0]
         if x.ndim == 1:
@@ -120,11 +107,9 @@ def writefile(filename: str, x: np.ndarray, fs: int = 48000) -> None:
     """
     _, file_extension = os.path.splitext(os.path.basename(filename))
 
-    clipped_samples = np.sum(
-        np.logical_or(x < np.iinfo(np.int16).min, x > np.iinfo(np.int16).max)
-    )
+    clipped_samples = np.sum(np.logical_or(x < np.iinfo(np.int16).min, x > np.iinfo(np.int16).max))
     if clipped_samples > 0:
-        warnings.warn(f"  Warning: {clipped_samples} samples clipped")
+        print("  Warning: %i samples clipped"%clipped_samples)
         x = np.clip(x, np.iinfo(np.int16).min, np.iinfo(np.int16).max)
 
     if file_extension == ".wav":
@@ -504,6 +489,7 @@ def loudnessinfo(
     in_sig: np.ndarray,
     in_fs: Optional[int] = 48000,
     in_format: Optional[str] = "MONO",
+    in_ls_layout_file: Optional[str] = None,
     output_loudness: Optional[int] = -26,
     loudness_tool: Optional[str] = "bs1770demo",
     use_rms: Optional[bool] = False,
@@ -538,10 +524,13 @@ def loudnessinfo(
     else:
         null_file = "/dev/null"
 
+    # check for binary
     if shutil.which(loudness_tool) is None:
         raise FileNotFoundError(f"The binary {loudness_tool} was not found in path!")
 
-    in_spfmt = spatialaudioformat.Format(in_format=in_format)
+    in_spfmt = spatialaudioformat.Format(
+        in_format=in_format, ls_layout_file=in_ls_layout_file
+    )
 
     if not (in_spfmt.isheadphones or in_spfmt.isloudspeaker or in_spfmt.ambi_order > 1):
         raise NotImplementedError(
@@ -554,7 +543,7 @@ def loudnessinfo(
         )
 
     with TemporaryDirectory() as tmp_dir:
-        tmp_file = os.path.join(tmp_dir, "tmp_loudness.pcm")
+        tmp_file = os.path.join(tmp_dir, "tmp.pcm")
 
         if "bs1770demo" in loudness_tool:
             """