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comparison libtwamr/pred_lt.c @ 398:df14b0c17e6d

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libtwamr: integrate pred_lt.c
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 06 May 2024 19:07:10 +0000
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397:9b699f30e6f3 398:df14b0c17e6d
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 : pred_lt.c
11 * Purpose : Compute the result of long term prediction
12 *
13 ********************************************************************************
14 */
15
16 /*
17 ********************************************************************************
18 * MODULE INCLUDE FILE AND VERSION ID
19 ********************************************************************************
20 */
21 #include "namespace.h"
22 #include "pred_lt.h"
23
24 /*
25 ********************************************************************************
26 * INCLUDE FILES
27 ********************************************************************************
28 */
29 #include "typedef.h"
30 #include "basic_op.h"
31 #include "no_count.h"
32 #include "cnst.h"
33
34 /*
35 ********************************************************************************
36 * LOCAL VARIABLES AND TABLES
37 ********************************************************************************
38 */
39 #define UP_SAMP_MAX 6
40 #define L_INTER10 (L_INTERPOL-1)
41 #define FIR_SIZE (UP_SAMP_MAX*L_INTER10+1)
42
43 /* 1/6 resolution interpolation filter (-3 dB at 3600 Hz) */
44 /* Note: the 1/3 resolution filter is simply a subsampled
45 * version of the 1/6 resolution filter, i.e. it uses
46 * every second coefficient:
47 *
48 * inter_3l[k] = inter_6[2*k], 0 <= k <= 3*L_INTER10
49 */
50 static const Word16 inter_6[FIR_SIZE] =
51 {
52 29443,
53 28346, 25207, 20449, 14701, 8693, 3143,
54 -1352, -4402, -5865, -5850, -4673, -2783,
55 -672, 1211, 2536, 3130, 2991, 2259,
56 1170, 0, -1001, -1652, -1868, -1666,
57 -1147, -464, 218, 756, 1060, 1099,
58 904, 550, 135, -245, -514, -634,
59 -602, -451, -231, 0, 191, 308,
60 340, 296, 198, 78, -36, -120,
61 -163, -165, -132, -79, -19, 34,
62 73, 91, 89, 70, 38, 0
63 };
64
65 /*
66 ********************************************************************************
67 * PUBLIC PROGRAM CODE
68 ********************************************************************************
69 */
70 /*************************************************************************
71 *
72 * FUNCTION: Pred_lt_3or6()
73 *
74 * PURPOSE: Compute the result of long term prediction with fractional
75 * interpolation of resolution 1/3 or 1/6. (Interpolated past
76 * excitation).
77 *
78 * DESCRIPTION:
79 * The past excitation signal at the given delay is interpolated at
80 * the given fraction to build the adaptive codebook excitation.
81 * On return exc[0..L_subfr-1] contains the interpolated signal
82 * (adaptive codebook excitation).
83 *
84 *************************************************************************/
85 void Pred_lt_3or6 (
86 Word16 exc[], /* in/out: excitation buffer */
87 Word16 T0, /* input : integer pitch lag */
88 Word16 frac, /* input : fraction of lag */
89 Word16 L_subfr, /* input : subframe size */
90 Word16 flag3 /* input : if set, upsampling rate = 3 (6 otherwise) */
91 )
92 {
93 Word16 i, j, k;
94 Word16 *x0, *x1, *x2;
95 const Word16 *c1, *c2;
96 Word32 s;
97
98 x0 = &exc[-T0]; move16 ();
99
100 frac = negate (frac);
101 test();
102 if (flag3 != 0)
103 {
104 frac = shl (frac, 1); /* inter_3l[k] = inter_6[2*k] -> k' = 2*k */
105 }
106
107 test ();
108 if (frac < 0)
109 {
110 frac = add (frac, UP_SAMP_MAX);
111 x0--;
112 }
113
114 for (j = 0; j < L_subfr; j++)
115 {
116 x1 = x0++; move16 ();
117 x2 = x0; move16 ();
118 c1 = &inter_6[frac];
119 c2 = &inter_6[sub (UP_SAMP_MAX, frac)];
120
121 s = 0; move32 ();
122 for (i = 0, k = 0; i < L_INTER10; i++, k += UP_SAMP_MAX)
123 {
124 s = L_mac (s, x1[-i], c1[k]);
125 s = L_mac (s, x2[i], c2[k]);
126 }
127
128 exc[j] = round (s); move16 ();
129 }
130
131 return;
132 }