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comparison dev/xmaxc-tables.c @ 247:56d3fbacd115

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dev: new program xmaxc-tables
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 12 May 2023 02:04:42 +0000
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246:a55fcc8b6daf 247:56d3fbacd115
1 /*
2 * For libgsmfrp: if we are going to initiate comfort noise generation
3 * upon receiving an invalid SID, and if we are going to harvest the
4 * needed LARc and Xmaxc parameters from the last speech frame, we'll
5 * need a way to compute a single mean Xmaxc from the 4 subframe Xmaxc
6 * parameters of that last speech frame.
7 *
8 * This program generates Xmaxc dequantization and requantization tables
9 * that are specifically optimized for performing this mean manipulation.
10 */
11
12 #include <stdio.h>
13 #include <stdint.h>
14 #include <stdlib.h>
15
16 static uint16_t dequant_table[64];
17 static uint8_t requant_table[1024];
18
19 static void
20 compute_dequant()
21 {
22 unsigned xmaxc, dequant, step;
23
24 dequant = 0;
25 step = 1;
26 for (xmaxc = 0; xmaxc < 64; xmaxc++) {
27 dequant_table[xmaxc] = dequant;
28 dequant += step;
29 if ((xmaxc & 7) == 7 && xmaxc != 7)
30 step <<= 1;
31 }
32 }
33
34 static void
35 compute_requant()
36 {
37 unsigned x, c;
38
39 for (x = 0; x < 1024; x++) {
40 for (c = 0; c < 63; c++) {
41 if (x < dequant_table[c+1])
42 break;
43 }
44 requant_table[x] = c;
45 }
46 }
47
48 static void
49 print_dequant()
50 {
51 unsigned c, r;
52
53 puts("const uint16_t dequant_table[64] = {");
54 for (c = 0; c < 64; c++) {
55 r = c & 7;
56 if (!r)
57 putchar('\t');
58 printf("%3u,", dequant_table[c]);
59 if (r == 7)
60 putchar('\n');
61 else
62 putchar(' ');
63 }
64 fputs("};\n\n", stdout);
65 }
66
67 static void
68 print_requant()
69 {
70 unsigned x, r;
71
72 puts("const uint8_t requant_table[1024] = {");
73 for (x = 0; x < 1024; x++) {
74 r = x & 15;
75 if (!r)
76 putchar('\t');
77 printf("%2u,", requant_table[x]);
78 if (r == 15)
79 putchar('\n');
80 else
81 putchar(' ');
82 }
83 fputs("};\n", stdout);
84 }
85
86 main(argc, argv)
87 char **argv;
88 {
89 compute_dequant();
90 compute_requant();
91 print_dequant();
92 print_requant();
93 exit(0);
94 }