--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtwamr/vad1.h	Tue May 07 00:56:10 2024 +0000
@@ -0,0 +1,116 @@
+/*
+********************************************************************************
+**-------------------------------------------------------------------------**
+**                                                                         **
+**     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             : vad1.h
+*      Purpose          : Voice Activity Detection (VAD) for AMR (option 1)
+*
+********************************************************************************
+*/
+#ifndef vad1_h
+#define vad1_h "$Id $"
+ 
+/*
+********************************************************************************
+*                         INCLUDE FILES
+********************************************************************************
+*/
+#include "typedef.h"
+#include "cnst_vad.h"
+
+/*
+********************************************************************************
+*                         LOCAL VARIABLES AND TABLES
+********************************************************************************
+*/
+
+/*
+********************************************************************************
+*                         DEFINITION OF DATA TYPES
+********************************************************************************
+*/
+
+/* state variable */
+typedef struct {
+   
+   Word16 bckr_est[COMPLEN];    /* background noise estimate                */
+   Word16 ave_level[COMPLEN];   /* averaged input components for stationary */
+                                /*    estimation                            */
+   Word16 old_level[COMPLEN];   /* input levels of the previous frame       */
+   Word16 sub_level[COMPLEN];   /* input levels calculated at the end of
+                                      a frame (lookahead)                   */
+   Word16 a_data5[3][2];        /* memory for the filter bank               */
+   Word16 a_data3[5];           /* memory for the filter bank               */
+
+   Word16 burst_count;          /* counts length of a speech burst          */
+   Word16 hang_count;           /* hangover counter                         */
+   Word16 stat_count;           /* stationary counter                       */
+
+   /* Note that each of the following three variables (vadreg, pitch and tone)
+      holds 15 flags. Each flag reserves 1 bit of the variable. The newest
+      flag is in the bit 15 (assuming that LSB is bit 1 and MSB is bit 16). */
+   Word16 vadreg;               /* flags for intermediate VAD decisions     */
+   Word16 pitch;                /* flags for pitch detection                */
+   Word16 tone;                 /* flags for tone detection                 */
+   Word16 complex_high;         /* flags for complex detection              */
+   Word16 complex_low;          /* flags for complex detection              */
+
+   Word16 oldlag_count, oldlag; /* variables for pitch detection            */
+ 
+   Word16 complex_hang_count;   /* complex hangover counter, used by VAD    */
+   Word16 complex_hang_timer;   /* hangover initiator, used by CAD          */
+    
+   Word16 best_corr_hp;         /* FIP filtered value Q15                   */ 
+
+   Word16 speech_vad_decision;  /* final decision                           */
+   Word16 complex_warning;      /* complex background warning               */
+
+   Word16 sp_burst_count;       /* counts length of a speech burst incl
+                                   HO addition                              */
+   Word16 corr_hp_fast;         /* filtered value                           */ 
+} vadState1;
+
+/*
+********************************************************************************
+*                         DECLARATION OF PROTOTYPES
+********************************************************************************
+*/
+ 
+void vad1_reset (vadState1 *st);
+/* reset of pre processing state (i.e. set state memory to zero)
+   returns 0 on success
+ */
+
+void vad_complex_detection_update (vadState1 *st,      /* i/o : State struct     */
+                                   Word16 best_corr_hp /* i   : best Corr Q15    */
+                                   );
+
+void vad_tone_detection (vadState1 *st, /* i/o : State struct            */
+                         Word32 t0,     /* i   : autocorrelation maxima  */
+                         Word32 t1      /* i   : energy                  */
+                         );
+
+void vad_tone_detection_update (
+                vadState1 *st,             /* i/o : State struct              */
+                Word16 one_lag_per_frame   /* i   : 1 if one open-loop lag is
+                                              calculated per each frame,
+                                              otherwise 0                     */
+                );
+
+void vad_pitch_detection (vadState1 *st,  /* i/o : State struct                  */
+                          Word16 lags[]   /* i   : speech encoder open loop lags */
+                          );
+
+Word16 vad1 (vadState1 *st,  /* i/o : State struct                      */
+            Word16 in_buf[]  /* i   : samples of the input frame 
+                                inbuf[159] is the very last sample,
+                                incl lookahead                          */
+            );
+#endif