--- a/libtwamr/Makefile	Thu Apr 18 19:47:13 2024 +0000
+++ b/libtwamr/Makefile	Thu Apr 18 20:05:14 2024 +0000
@@ -2,8 +2,8 @@
 CFLAGS=	-O2
 OBJS=	a_refl.o agc.o autocorr.o az_lsp.o b_cn_cod.o basicop2.o bgnscd.o \
 	bitno.o bits2prm.o c1035pf.o c2_11pf.o c2_9pf.o c3_14pf.o c4_17pf.o \
-	c8_31pf.o cor_h.o gmed_n.o graytab.o inv_sqrt.o oper_32b.o prmno.o \
-	s10_8pf.o set_sign.o sqrt_l.o tls_flags.o window.o
+	c8_31pf.o c_g_aver.o cor_h.o gmed_n.o graytab.o inv_sqrt.o oper_32b.o \
+	prmno.o s10_8pf.o set_sign.o sqrt_l.o tls_flags.o window.o
 LIB=	libtwamr.a
 
 INSTALL_PREFIX=	/usr/local

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtwamr/c_g_aver.c	Thu Apr 18 20:05:14 2024 +0000
@@ -0,0 +1,260 @@
+/*************************************************************************
+*
+*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
+*                                R99   Version 3.3.0                
+*                                REL-4 Version 4.1.0                
+*
+********************************************************************************
+*
+*      File             : c_g_aver.c
+*      Purpose          : 
+*
+********************************************************************************
+*/
+
+/*
+********************************************************************************
+*                         MODULE INCLUDE FILE AND VERSION ID
+********************************************************************************
+*/
+#include "namespace.h"
+#include "c_g_aver.h"
+
+#include "tw_amr.h"
+#include "typedef.h"
+#include "basic_op.h"
+#include "no_count.h"
+#include "cnst.h"
+#include "memops.h"
+
+/*
+********************************************************************************
+*                         LOCAL VARIABLES AND TABLES
+********************************************************************************
+*/
+/*-----------------------------------------------------------------*
+ *   Decoder constant parameters (defined in "cnst.h")             *
+ *-----------------------------------------------------------------*
+ *   L_FRAME       : Frame size.                                   *
+ *   L_SUBFR       : Sub-frame size.                               *
+ *-----------------------------------------------------------------*/
+
+/*
+********************************************************************************
+*                         PUBLIC PROGRAM CODE
+********************************************************************************
+*/
+/*
+**************************************************************************
+*
+*  Function    : Cb_gain_average_reset
+*  Purpose     : Resets state memory
+*
+**************************************************************************
+*/
+void Cb_gain_average_reset (Cb_gain_averageState *state)
+{
+   /* Static vectors to zero */
+   Set_zero (state->cbGainHistory, L_CBGAINHIST);
+
+   /* Initialize hangover handling */
+   state->hangVar = 0;
+   state->hangCount= 0;
+}
+
+/*
+**************************************************************************
+*
+*  Function    : Cb_gain_average
+*  Purpose     : 
+*  Returns     : The mix cb gains for MR475, MR515, MR59, MR67, MR102; gain_code other modes 
+*
+**************************************************************************
+*/
+Word16 Cb_gain_average (    
+   Cb_gain_averageState *st, /* i/o : State variables for CB gain avergeing   */
+   enum Mode mode,           /* i   : AMR mode                                */
+   Word16 gain_code,         /* i   : CB gain                              Q1 */
+   Word16 lsp[],             /* i   : The LSP for the current frame       Q15 */
+   Word16 lspAver[],         /* i   : The average of LSP for 8 frames     Q15 */
+   Word16 bfi,               /* i   : bad frame indication flag               */
+   Word16 prev_bf,           /* i   : previous bad frame indication flag      */
+   Word16 pdfi,              /* i   : potential degraded bad frame ind flag   */
+   Word16 prev_pdf,          /* i   : prev pot. degraded bad frame ind flag   */
+   Word16 inBackgroundNoise, /* i   : background noise decision               */
+   Word16 voicedHangover     /* i   : # of frames after last voiced frame     */
+   )
+{
+   /*---------------------------------------------------------*
+    * Compute mixed cb gain, used to make cb gain more        *
+    * smooth in background noise for modes 5.15, 5.9 and 6.7  *
+    * states that needs to be updated by all                  *
+    *---------------------------------------------------------*/
+   Word16 i;
+   Word16 cbGainMix, diff, tmp_diff, bgMix, cbGainMean;
+   Word32 L_sum;
+   Word16 tmp[M], tmp1, tmp2, shift1, shift2, shift;
+
+   /* set correct cbGainMix for MR74, MR795, MR122 */
+   cbGainMix = gain_code;             move16 (); 
+   
+   /*-------------------------------------------------------*
+    *   Store list of CB gain needed in the CB gain         *
+    *   averaging                                           *
+    *-------------------------------------------------------*/
+   for (i = 0; i < (L_CBGAINHIST-1); i++)
+   {
+      st->cbGainHistory[i] = st->cbGainHistory[i+1];    move16 ();
+   }
+   st->cbGainHistory[L_CBGAINHIST-1] = gain_code;       move16 ();
+   
+   /* compute lsp difference */
+   for (i = 0; i < M; i++) {
+      tmp1 = abs_s(sub(lspAver[i], lsp[i]));  /* Q15       */
+      shift1 = sub(norm_s(tmp1), 1);          /* Qn        */
+      tmp1 = shl(tmp1, shift1);               /* Q15+Qn    */
+      shift2 = norm_s(lspAver[i]);            /* Qm        */
+      tmp2 = shl(lspAver[i], shift2);         /* Q15+Qm    */
+      tmp[i] = div_s(tmp1, tmp2);             /* Q15+(Q15+Qn)-(Q15+Qm) */
+                                              move16 ();
+      shift = sub(add(2, shift1), shift2);
+      test ();
+      if (shift >= 0)
+      {
+         tmp[i] = shr(tmp[i], shift); move16 ();          /* Q15+Qn-Qm-Qx=Q13 */
+      }
+      else
+      {
+         tmp[i] = shl(tmp[i], negate(shift));  move16 (); /* Q15+Qn-Qm-Qx=Q13 */
+      }
+   }
+   
+   diff = tmp[0];                                   move16 ();
+   for (i = 1; i < M; i++) { 
+      diff = add(diff, tmp[i]);       /* Q13 */
+   }   
+
+   /* Compute hangover */
+   test ();
+   if (sub(diff, 5325) > 0)  /* 0.65 in Q11 */
+   {
+      st->hangVar = add(st->hangVar, 1);
+   }
+   else
+   {
+      st->hangVar = 0;     move16 ();
+   }
+
+   test (); 
+   if (sub(st->hangVar, 10) > 0)
+   {
+      st->hangCount = 0;  /* Speech period, reset hangover variable */ move16 ();
+   }
+
+   /* Compute mix constant (bgMix) */   
+   bgMix = 8192;    /* 1 in Q13 */     move16 ();
+   test (); 
+   if ((sub(mode, MR67) <= 0) || (sub(mode, MR102) == 0))  
+      /* MR475, MR515, MR59, MR67, MR102 */
+   {
+      /* if errors and presumed noise make smoothing probability stronger */
+      test (); test (); test (); test (); test (); test(); test (); test (); test ();
+      if (((((pdfi != 0) && (prev_pdf != 0)) || (bfi != 0) || (prev_bf != 0)) &&
+          (sub(voicedHangover, 1) > 0) && (inBackgroundNoise != 0) && 
+          ((sub(mode, MR475) == 0) ||
+           (sub(mode, MR515) == 0) ||
+           (sub(mode, MR59) == 0)) ))
+      {
+         /* bgMix = min(0.25, max(0.0, diff-0.55)) / 0.25; */
+         tmp_diff = sub(diff, 4506);   /* 0.55 in Q13 */
+
+         /* max(0.0, diff-0.55) */
+         test ();
+         if (tmp_diff > 0)
+         {
+            tmp1 = tmp_diff;       move16 ();
+         }
+         else
+         {
+            tmp1 = 0;              move16 ();
+         }
+
+         /* min(0.25, tmp1) */
+         test ();
+         if (sub(2048, tmp1) < 0)
+         {
+            bgMix = 8192;              move16 ();
+         }
+         else
+         {
+            bgMix = shl(tmp1, 2);
+         }
+      }
+      else
+      {
+         /* bgMix = min(0.25, max(0.0, diff-0.40)) / 0.25; */        
+         tmp_diff = sub(diff, 3277); /* 0.4 in Q13 */
+
+         /* max(0.0, diff-0.40) */
+         test ();
+         if (tmp_diff > 0)
+         {
+            tmp1 = tmp_diff;        move16 ();
+         }
+         else
+         {
+            tmp1 = 0;               move16 ();
+         }
+
+         /* min(0.25, tmp1) */
+         test ();
+         if (sub(2048, tmp1) < 0)
+         {
+            bgMix = 8192;           move16 ();
+         }
+         else
+         {
+            bgMix = shl(tmp1, 2);
+         }
+      }
+
+      test (); test ();
+      if ((sub(st->hangCount, 40) < 0) || (sub(diff, 5325) > 0)) /* 0.65 in Q13 */
+      {
+         bgMix = 8192;  /* disable mix if too short time since */ move16 ();
+      }
+
+      /* Smoothen the cb gain trajectory  */
+      /* smoothing depends on mix constant bgMix */
+      L_sum = L_mult(6554, st->cbGainHistory[2]);     /* 0.2 in Q15; L_sum in Q17 */   
+      for (i = 3; i < L_CBGAINHIST; i++)
+      {
+         L_sum = L_mac(L_sum, 6554, st->cbGainHistory[i]);
+      }
+      cbGainMean = round(L_sum);                      /* Q1 */
+      
+      /* more smoothing in error and bg noise (NB no DFI used  here) */
+      test (); test (); test (); test (); test(); test();
+      if (((bfi != 0) || (prev_bf != 0)) && (inBackgroundNoise != 0) &&
+          ((sub(mode, MR475) == 0) ||
+           (sub(mode, MR515) == 0) ||
+           (sub(mode, MR59) == 0)) )
+      {
+         L_sum = L_mult(4681, st->cbGainHistory[0]);  /* 0.143 in Q15; L_sum in Q17 */     
+         for (i = 1; i < L_CBGAINHIST; i++)
+         {
+            L_sum = L_mac(L_sum, 4681, st->cbGainHistory[i]);
+         }
+         cbGainMean = round(L_sum);                   /* Q1 */
+      }
+      
+      /* cbGainMix = bgMix*cbGainMix + (1-bgMix)*cbGainMean; */
+      L_sum = L_mult(bgMix, cbGainMix);               /* L_sum in Q15 */
+      L_sum = L_mac(L_sum, 8192, cbGainMean);         
+      L_sum = L_msu(L_sum, bgMix, cbGainMean);
+      cbGainMix = round(L_shl(L_sum, 2));             /* Q1 */
+   }
+   
+   st->hangCount = add(st->hangCount, 1);
+   return cbGainMix;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtwamr/c_g_aver.h	Thu Apr 18 20:05:14 2024 +0000
@@ -0,0 +1,88 @@
+/*
+********************************************************************************
+*
+*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
+*                                R99   Version 3.3.0                
+*                                REL-4 Version 4.1.0                
+*
+********************************************************************************
+*
+*      File             : c_g_aver.h
+*      Purpose          : Background noise source charateristic detector (SCD)
+*
+********************************************************************************
+*/
+#ifndef c_g_aver_h
+#define c_g_aver_h "$Id $"
+ 
+/*
+********************************************************************************
+*                         INCLUDE FILES
+********************************************************************************
+*/
+#include "tw_amr.h"
+#include "typedef.h"
+#include "cnst.h"
+
+/*
+********************************************************************************
+*                         LOCAL VARIABLES AND TABLES
+********************************************************************************
+*/
+#define L_CBGAINHIST 7
+
+/*
+********************************************************************************
+*                         DEFINITION OF DATA TYPES
+********************************************************************************
+*/
+typedef struct{
+   /* history vector of past synthesis speech energy */
+   Word16 cbGainHistory[L_CBGAINHIST];
+   
+   /* state flags */
+   Word16 hangVar;       /* counter; */
+   Word16 hangCount;     /* counter; */
+
+} Cb_gain_averageState;
+ 
+/*
+********************************************************************************
+*                         DECLARATION OF PROTOTYPES
+********************************************************************************
+*/
+/*
+**************************************************************************
+*
+*  Function    : Cb_gain_average_reset
+*  Purpose     : Resets state memory
+*  Returns     : 0 on success
+*
+**************************************************************************
+*/
+void Cb_gain_average_reset (Cb_gain_averageState *st);
+ 
+/*
+**************************************************************************
+*
+*  Function    : Cb_gain_average
+*  Purpose     : Charaterice synthesis speech and detect background noise
+*  Returns     : background noise decision; 0 = bgn, 1 = no bgn
+*
+**************************************************************************
+*/
+Word16 Cb_gain_average (
+   Cb_gain_averageState *st, /* i/o : State variables for CB gain avergeing   */
+   enum Mode mode,           /* i   : AMR mode                                */
+   Word16 gain_code,         /* i   : CB gain                              Q1 */
+   Word16 lsp[],             /* i   : The LSP for the current frame       Q15 */
+   Word16 lspAver[],         /* i   : The average of LSP for 8 frames     Q15 */
+   Word16 bfi,               /* i   : bad frame indication flag               */
+   Word16 prev_bf,           /* i   : previous bad frame indication flag      */
+   Word16 pdfi,              /* i   : potential degraded bad frame ind flag   */
+   Word16 prev_pdf,          /* i   : prev pot. degraded bad frame ind flag   */
+   Word16 inBackgroundNoise, /* i   : background noise decision               */
+   Word16 voicedHangover     /* i   : # of frames after last voiced frame     */
+);
+ 
+#endif

--- a/libtwamr/namespace.h	Thu Apr 18 19:47:13 2024 +0000
+++ b/libtwamr/namespace.h	Thu Apr 18 20:05:14 2024 +0000
@@ -90,6 +90,9 @@
 #define	window_160_80	AMR__window_160_80
 #define	window_232_8	AMR__window_232_8
 
+#define	Cb_gain_average		AMR__Cb_gain_average
+#define	Cb_gain_average_reset	AMR__Cb_gain_average_reset
+
 #define	code_2i40_9bits		AMR__code_2i40_9bits
 #define	code_2i40_11bits	AMR__code_2i40_11bits
 #define	code_3i40_14bits	AMR__code_3i40_14bits