From 9b47beb14ffc065d7cb5706afb477b99ae1107c0 Mon Sep 17 00:00:00 2001
From: vaclav <vaclav.eksler@usherbrooke.ca>
Date: Mon, 19 Jun 2023 14:08:20 +0200
Subject: [PATCH] issue 562: fix ISM2 at 64kbps quality; under
 FIX_562_ISM2_64KBPS

---
 lib_com/ivas_ism_com.c          | 21 +++++++++++++++++++++
 lib_com/options.h               |  3 +++
 lib_dec/ivas_ism_metadata_dec.c |  5 +++++
 lib_enc/ivas_ism_metadata_enc.c |  5 +++++
 4 files changed, 34 insertions(+)

diff --git a/lib_com/ivas_ism_com.c b/lib_com/ivas_ism_com.c
index bd064a584a..703983a1d4 100644
--- a/lib_com/ivas_ism_com.c
+++ b/lib_com/ivas_ism_com.c
@@ -61,6 +61,10 @@
 #define BETA_ISM_LOW_IMP    0.6f
 #define BETA_ISM_MEDIUM_IMP 0.8f
 
+#ifdef FIX_562_ISM2_64KBPS
+#define MAX_BRATE_TCX_32k 48000
+#endif
+
 
 /*-------------------------------------------------------------------*
  * bitbudget_to_brate()
@@ -346,6 +350,23 @@ ivas_error ivas_ism_config(
             bits_CoreCoder[ch] = tmp;
         }
 
+#ifdef FIX_562_ISM2_64KBPS
+        /* limitaton to avoid too high bitrate in one active TCX channel */
+        if ( element_brate[0] >= SCE_CORE_16k_LOW_LIMIT && element_brate[0] <= IVAS_32k )
+        {
+            diff = 0;
+            limit_high = MAX_BRATE_TCX_32k / FRAMES_PER_SEC;
+
+            for ( ch = 0; ch < n_ISms; ch++ )
+            {
+                tmp = (int16_t) min( bits_CoreCoder[ch], limit_high );
+
+                diff += bits_CoreCoder[ch] - tmp;
+                bits_CoreCoder[ch] = tmp;
+            }
+        }
+#endif
+
         if ( diff > 0 )
         {
             ch = 0;
diff --git a/lib_com/options.h b/lib_com/options.h
index e51736a79f..0b79fc733c 100755
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -162,6 +162,9 @@
 #define FIX_522_ISM_FIRST_SID                           /* VA: fix ISM decoder crash if first received frame is an SID */
 
 
+#define FIX_562_ISM2_64KBPS                             /* VA: issue 562: fix ISM2 at 64kbps issue */
+
+
 /* ################## End DEVELOPMENT switches ######################### */
 /* clang-format on */
 
diff --git a/lib_dec/ivas_ism_metadata_dec.c b/lib_dec/ivas_ism_metadata_dec.c
index eb14177b0b..e6c9951b48 100644
--- a/lib_dec/ivas_ism_metadata_dec.c
+++ b/lib_dec/ivas_ism_metadata_dec.c
@@ -542,7 +542,12 @@ ivas_error ivas_ism_metadata_dec(
             if ( ism_mode == ISM_MODE_DISC )
             {
 #ifdef FIX_532_ISM_MD_INACTIVE
+#ifdef FIX_562_ISM2_64KBPS
+                if ( ism_imp[ch] == ISM_NO_META && ( ( total_brate[ch] < ACELP_8k00 && element_brate[ch] < SCE_CORE_16k_LOW_LIMIT ) ||
+                                                     ( total_brate[ch] <= ACELP_16k_LOW_LIMIT && element_brate[ch] >= SCE_CORE_16k_LOW_LIMIT ) ) )
+#else
                 if ( ism_imp[ch] == ISM_NO_META && total_brate[ch] < ACELP_8k00 )
+#endif
 #else
                 if ( hIsmMeta[ch]->ism_metadata_flag == 0 && localVAD[ch] == 0 && ism_metadata_flag_global )
 #endif
diff --git a/lib_enc/ivas_ism_metadata_enc.c b/lib_enc/ivas_ism_metadata_enc.c
index 27a4a3b0cb..003676c56b 100644
--- a/lib_enc/ivas_ism_metadata_enc.c
+++ b/lib_enc/ivas_ism_metadata_enc.c
@@ -636,7 +636,12 @@ ivas_error ivas_ism_metadata_enc(
         if ( ism_mode == ISM_MODE_DISC )
         {
 #ifdef FIX_532_ISM_MD_INACTIVE
+#ifdef FIX_562_ISM2_64KBPS
+            if ( ism_imp[ch] == ISM_NO_META && ( ( total_brate[ch] < ACELP_8k00 && element_brate[ch] < SCE_CORE_16k_LOW_LIMIT ) ||
+                                                 ( total_brate[ch] <= ACELP_16k_LOW_LIMIT && element_brate[ch] >= SCE_CORE_16k_LOW_LIMIT ) ) )
+#else
             if ( ism_imp[ch] == ISM_NO_META && total_brate[ch] < ACELP_8k00 )
+#endif
 #else
             if ( hIsmMeta[ch]->ism_metadata_flag == 0 && vad_flag[ch] == 0 && ism_metadata_flag_global )
 #endif
-- 
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