--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtwamr/vad2.h	Tue May 07 01:14:14 2024 +0000
@@ -0,0 +1,113 @@
+/*
+********************************************************************************
+*                                                                        
+*      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             : vad2.h
+*      Purpose          : Voice Activity Detection (VAD) for AMR (option 2)
+*
+********************************************************************************
+*/
+
+#ifndef vad2_h
+#define vad2_h "$Id $"
+
+#include "typedef.h"
+
+/***** Defines ****/
+
+#define		YES		1
+#define		NO		0
+#define		ON		1
+#define		OFF		0
+#define		TRUE		1
+#define		FALSE		0
+
+#define         FRM_LEN                 80
+#define         DELAY                   24
+#define         FFT_LEN                 128
+
+#define         NUM_CHAN                16
+#define         LO_CHAN                 0
+#define         HI_CHAN                 15
+
+#define         UPDATE_THLD             35
+#define         HYSTER_CNT_THLD         6
+#define         UPDATE_CNT_THLD         50
+
+#define		SHIFT_STATE_0		0		/* channel energy scaled as 22,9 */
+#define		SHIFT_STATE_1		1		/* channel energy scaled as 27,4 */
+
+#define		NOISE_FLOOR_CHAN_0	512		/* 1.0    scaled as 22,9 */
+#define		MIN_CHAN_ENRG_0		32		/* 0.0625 scaled as 22,9 */
+#define		MIN_NOISE_ENRG_0	32		/* 0.0625 scaled as 22,9 */
+#define		INE_NOISE_0		8192		/* 16.0   scaled as 22,9 */
+#define		FRACTIONAL_BITS_0	9		/* used as input to fn10Log10() */
+
+#define		NOISE_FLOOR_CHAN_1	16		/* 1.0    scaled as 27,4 */
+#define		MIN_CHAN_ENRG_1		1		/* 0.0625 scaled as 27,4 */
+#define		MIN_NOISE_ENRG_1	1		/* 0.0625 scaled as 27,4 */
+#define		INE_NOISE_1		256		/* 16.0   scaled as 27,4 */
+#define		FRACTIONAL_BITS_1	4		/* used as input to fn10Log10() */
+
+#define		STATE_1_TO_0_SHIFT_R	(FRACTIONAL_BITS_1-FRACTIONAL_BITS_0)	/* state correction factor */
+#define		STATE_0_TO_1_SHIFT_R	(FRACTIONAL_BITS_0-FRACTIONAL_BITS_1)	/* state correction factor */
+
+#define         HIGH_ALPHA              29491		/* 0.9 scaled as 0,15 */
+#define         LOW_ALPHA               22938		/* 0.7 scaled as 0,15 */
+#define         ALPHA_RANGE             (HIGH_ALPHA - LOW_ALPHA)
+#define         DEV_THLD                7168		/* 28.0 scaled as 7,8 */
+
+#define         PRE_EMP_FAC             (-26214)	/* -0.8 scaled as 0,15 */
+
+#define         CEE_SM_FAC              18022		/* 0.55 scaled as 0,15 */
+#define         ONE_MINUS_CEE_SM_FAC    14746		/* 0.45 scaled as 0,15 */
+
+#define         CNE_SM_FAC              3277		/* 0.1 scaled as 0,15 */
+#define         ONE_MINUS_CNE_SM_FAC    29491		/* 0.9 scaled as 0,15 */
+
+#define         FFT_HEADROOM            2
+
+
+typedef struct
+{
+	Word16 pre_emp_mem;
+	Word16 update_cnt;
+	Word16 hyster_cnt;
+	Word16 last_update_cnt;
+	Word16 ch_enrg_long_db[NUM_CHAN];	/* scaled as 7,8  */
+
+	Word32 Lframe_cnt;
+	Word32 Lch_enrg[NUM_CHAN];	/* scaled as 22,9 or 27,4 */
+	Word32 Lch_noise[NUM_CHAN];	/* scaled as 22,9 */
+
+	Word16 last_normb_shift;	/* last block norm shift count */
+
+	Word16 tsnr;			/* total signal-to-noise ratio in dB (scaled as 7,8) */
+	Word16 hangover;
+	Word16 burstcount;
+	Word16 fupdate_flag;		/* forced update flag from previous frame */
+	Word16 negSNRvar;		/* Negative SNR variance (scaled as 7,8) */
+	Word16 negSNRbias;		/* sensitivity bias from negative SNR variance (scaled as 15,0) */
+
+	Word16 shift_state;		/* use 22,9 or 27,4 scaling for ch_enrg[] */
+
+	Word32 L_R0;
+	Word32 L_Rmax;
+	Flag   LTP_flag;		/* Use to indicate the the LTP gain is > LTP_THRESH */
+
+} vadState2;
+
+/**** Prototypes ****/
+
+Word16	vad2 (Word16 *farray_ptr, vadState2 *st);
+void	vad2_reset (vadState2 *st);
+
+void	r_fft (Word16 *farray_ptr);
+void	LTP_flag_update (vadState2 *st, Word16 mode);
+
+#endif