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comparison libtwamr/dec_gain.c @ 356:5ccfe176bae1

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libtwamr: integrate dec_gain.c
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 05 May 2024 22:24:42 +0000
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355:9beb01439a90 356:5ccfe176bae1
1 /*
2 ********************************************************************************
3 *
4 * GSM AMR-NB speech codec R98 Version 7.6.0 December 12, 2001
5 * R99 Version 3.3.0
6 * REL-4 Version 4.1.0
7 *
8 ********************************************************************************
9 *
10 * File : dec_gain.c
11 * Purpose : Decode the pitch and codebook gains
12 *
13 ********************************************************************************
14 */
15
16 /*
17 ********************************************************************************
18 * MODULE INCLUDE FILE AND VERSION ID
19 ********************************************************************************
20 */
21 #include "namespace.h"
22 #include "dec_gain.h"
23
24 /*
25 ********************************************************************************
26 * INCLUDE FILES
27 ********************************************************************************
28 */
29 #include <stddef.h>
30 #include "tw_amr.h"
31 #include "typedef.h"
32 #include "basic_op.h"
33 #include "oper_32b.h"
34 #include "no_count.h"
35 #include "cnst.h"
36 #include "pow2.h"
37 #include "log2.h"
38 #include "gc_pred.h"
39 #include "qua_gain_tab.h"
40
41 /*
42 ********************************************************************************
43 * PUBLIC PROGRAM CODE
44 ********************************************************************************
45 */
46
47 /*************************************************************************
48 *
49 * FUNCTION: Dec_gain()
50 *
51 * PURPOSE: Decode the pitch and codebook gains
52 *
53 ************************************************************************/
54 void Dec_gain(
55 gc_predState *pred_state, /* i/o: MA predictor state */
56 enum Mode mode, /* i : AMR mode */
57 Word16 index, /* i : index of quantization. */
58 Word16 code[], /* i : Innovative vector. */
59 Word16 evenSubfr, /* i : Flag for even subframes */
60 Word16 * gain_pit, /* o : Pitch gain. */
61 Word16 * gain_cod /* o : Code gain. */
62 )
63 {
64 const Word16 *p;
65 Word16 frac, gcode0, exp, qua_ener, qua_ener_MR122;
66 Word16 g_code;
67 Word32 L_tmp;
68
69 /* Read the quantized gains (table depends on mode) */
70 index = shl (index, 2);
71
72 test(); test(); test();
73 if ( sub (mode, MR102) == 0
74 || sub (mode, MR74) == 0
75 || sub (mode, MR67) == 0)
76 {
77 p = &table_gain_highrates[index]; move16 ();
78
79 *gain_pit = *p++; move16 ();
80 g_code = *p++; move16 ();
81 qua_ener_MR122 = *p++; move16 ();
82 qua_ener = *p; move16 ();
83 }
84 else
85 {
86 test();
87 if (sub (mode, MR475) == 0)
88 {
89 index = add (index, shl(sub(1, evenSubfr), 1));
90 p = &table_gain_MR475[index]; move16 ();
91
92 *gain_pit = *p++; move16 ();
93 g_code = *p++; move16 ();
94
95 /*---------------------------------------------------------*
96 * calculate predictor update values (not stored in 4.75 *
97 * quantizer table to save space): *
98 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *
99 * *
100 * qua_ener = log2(g) *
101 * qua_ener_MR122 = 20*log10(g) *
102 *---------------------------------------------------------*/
103
104 /* Log2(x Q12) = log2(x) + 12 */
105 Log2 (L_deposit_l (g_code), &exp, &frac);
106 exp = sub(exp, 12);
107
108 qua_ener_MR122 = add (shr_r (frac, 5), shl (exp, 10));
109
110 /* 24660 Q12 ~= 6.0206 = 20*log10(2) */
111 L_tmp = Mpy_32_16(exp, frac, 24660);
112 qua_ener = round (L_shl (L_tmp, 13)); /* Q12 * Q0 = Q13 -> Q10 */
113 }
114 else
115 {
116 p = &table_gain_lowrates[index]; move16 ();
117
118 *gain_pit = *p++; move16 ();
119 g_code = *p++; move16 ();
120 qua_ener_MR122 = *p++; move16 ();
121 qua_ener = *p; move16 ();
122 }
123 }
124
125 /*-------------------------------------------------------------------*
126 * predict codebook gain *
127 * ~~~~~~~~~~~~~~~~~~~~~ *
128 * gc0 = Pow2(int(d)+frac(d)) *
129 * = 2^exp + 2^frac *
130 * *
131 * gcode0 (Q14) = 2^14*2^frac = gc0 * 2^(14-exp) *
132 *-------------------------------------------------------------------*/
133
134 gc_pred(pred_state, mode, code, &exp, &frac, NULL, NULL);
135
136 gcode0 = extract_l(Pow2(14, frac));
137
138 /*------------------------------------------------------------------*
139 * read quantized gains, update table of past quantized energies *
140 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *
141 * st->past_qua_en(Q10) = 20 * Log10(g_fac) / constant *
142 * = Log2(g_fac) *
143 * = qua_ener *
144 * constant = 20*Log10(2) *
145 *------------------------------------------------------------------*/
146
147 L_tmp = L_mult(g_code, gcode0);
148 L_tmp = L_shr(L_tmp, sub(10, exp));
149 *gain_cod = extract_h(L_tmp);
150
151 /* update table of past quantized energies */
152
153 gc_pred_update(pred_state, qua_ener_MR122, qua_ener);
154
155 return;
156 }