From acc0842801e36737033f0b8064fb88416e67e0df Mon Sep 17 00:00:00 2001
From: knj <jan.kiene@iis.fraunhofer.de>
Date: Tue, 21 Nov 2023 16:08:32 +0100
Subject: [PATCH] add fix for noise seed handling in ism cng

---
 lib_com/options.h          |  1 +
 lib_dec/fd_cng_dec.c       | 12 ++++++++++++
 lib_dec/ivas_init_dec.c    | 14 ++++++++++++++
 lib_dec/ivas_ism_dtx_dec.c | 11 +++++++++++
 4 files changed, 38 insertions(+)

diff --git a/lib_com/options.h b/lib_com/options.h
index 2c04e3772d..6cc2490374 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -171,6 +171,7 @@
 #define NONBE_FIX_225_MASA_EXT_REND                           /* Nokia: Resolve #225: Complete MASA external renderer implementation */
 #define NONBE_FIX_897_USAN_WITH_MASA_RENDERING                /* Nokia: issue #897: USAN null pointer in MASA external renderer to Ambisonics */
 #define NONBE_FIX_811_DFT_DOUBLE_TO_FLOAT                     /* FhG: issue 811: change double precision functions to float in DFT Stereo */
+#define NONBE_FIX_DISCRETE_ISM_NOISE_SEED_HANDLING            /* FhG: fix handling of common and differing noise seeds in SCEs for ISM DTX */
 
 /* ##################### End NON-BE switches ########################### */
 
diff --git a/lib_dec/fd_cng_dec.c b/lib_dec/fd_cng_dec.c
index 5e36f024f8..348cfd1227 100644
--- a/lib_dec/fd_cng_dec.c
+++ b/lib_dec/fd_cng_dec.c
@@ -1104,10 +1104,17 @@ void generate_comfort_noise_dec(
     c2 = (float) sqrt( 1 - hFdCngCom->coherence );
 
     seed2 = &( hFdCngCom->seed2 );
+#ifdef NONBE_FIX_DISCRETE_ISM_NOISE_SEED_HANDLING
+    if ( st->element_mode == IVAS_CPE_MDCT && st->idchan == 1 )
+    {
+        seed2 = &( hFdCngCom->seed3 );
+    }
+#else
     if ( ( st->element_mode == IVAS_CPE_MDCT && st->idchan == 1 ) || ( st->element_mode == IVAS_SCE && st->cng_ism_flag ) )
     {
         seed2 = &( hFdCngCom->seed3 );
     }
+#endif
 
     /* Generate Gaussian random noise in real and imaginary parts of the FFT bins
       Amplitudes are adjusted to the estimated noise level cngNoiseLevel in each bin */
@@ -1354,11 +1361,16 @@ void generate_comfort_noise_dec_hf(
     float scale = CLDFB_SCALING / hFdCngCom->scalingFactor;
 
     int16_t *seed2 = &( hFdCngCom->seed );
+
     float tmp1, tmp2, c1 = 0.f, c2 = 0.f;
 
     if ( cng_coh_flag )
     {
+#ifdef NONBE_FIX_DISCRETE_ISM_NOISE_SEED_HANDLING
+        seed2 = &( hFdCngCom->seed2 );
+#else
         seed2 = &( hFdCngCom->seed3 );
+#endif
 
         c1 = (float) sqrt( hFdCngCom->coherence );
         c2 = (float) sqrt( 1 - hFdCngCom->coherence );
diff --git a/lib_dec/ivas_init_dec.c b/lib_dec/ivas_init_dec.c
index d9e32229c8..046f5af855 100644
--- a/lib_dec/ivas_init_dec.c
+++ b/lib_dec/ivas_init_dec.c
@@ -1338,10 +1338,24 @@ ivas_error ivas_init_decoder(
 
         st_ivas->hISMDTX.sce_id_dtx = 0;
 
+#ifdef NONBE_FIX_DISCRETE_ISM_NOISE_SEED_HANDLING
+        if ( st_ivas->ism_mode == ISM_MODE_PARAM )
+        {
+            st_ivas->hSCE[0]->hCoreCoder[0]->hFdCngDec->hFdCngCom->seed2 = st_ivas->hSCE[0]->hCoreCoder[0]->hFdCngDec->hFdCngCom->seed3;
+        }
+        else if ( st_ivas->ism_mode == ISM_MODE_DISC )
+        {
+            for ( sce_id = 0; sce_id < st_ivas->nSCE; ++sce_id )
+            {
+                st_ivas->hSCE[sce_id]->hCoreCoder[0]->hFdCngDec->hFdCngCom->seed2 = 2 + sce_id;
+            }
+        }
+#else
         if ( st_ivas->ism_mode == ISM_MODE_PARAM )
         {
             st_ivas->hSCE[1]->hCoreCoder[0]->hFdCngDec->hFdCngCom->seed3 = st_ivas->hSCE[0]->hCoreCoder[0]->hFdCngDec->hFdCngCom->seed2;
         }
+#endif
     }
     else if ( st_ivas->ivas_format == SBA_FORMAT )
     {
diff --git a/lib_dec/ivas_ism_dtx_dec.c b/lib_dec/ivas_ism_dtx_dec.c
index 8899696bec..2d37aa18df 100644
--- a/lib_dec/ivas_ism_dtx_dec.c
+++ b/lib_dec/ivas_ism_dtx_dec.c
@@ -135,6 +135,17 @@ ivas_error ivas_ism_dtx_dec(
         }
     }
 
+#ifdef NONBE_FIX_DISCRETE_ISM_NOISE_SEED_HANDLING
+    /* synch common seed between SCEs */
+    if ( st_ivas->ism_mode == ISM_MODE_DISC )
+    {
+        for ( ch = 0; ch < nchan_ism; ++ch )
+        {
+            st_ivas->hSCE[ch]->hCoreCoder[0]->hFdCngDec->hFdCngCom->seed = st_ivas->hSCE[st_ivas->hISMDTX.sce_id_dtx]->hCoreCoder[0]->hFdCngDec->hFdCngCom->seed;
+        }
+    }
+#endif
+
     update_last_metadata( nchan_ism, st_ivas->hIsmMetaData, md_diff_flag );
 
     st_ivas->hISMDTX.ism_dtx_hangover_cnt = 0;
-- 
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