FreeCalypso > hg > gsm-codec-lib
view dev/xmaxc-tables.c @ 550:de333989a12b
document gsm[e]fr-decode-tw5[-r] utilities
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sat, 05 Oct 2024 02:16:48 +0000 |
parents | 56d3fbacd115 |
children |
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/* * For libgsmfrp: if we are going to initiate comfort noise generation * upon receiving an invalid SID, and if we are going to harvest the * needed LARc and Xmaxc parameters from the last speech frame, we'll * need a way to compute a single mean Xmaxc from the 4 subframe Xmaxc * parameters of that last speech frame. * * This program generates Xmaxc dequantization and requantization tables * that are specifically optimized for performing this mean manipulation. */ #include <stdio.h> #include <stdint.h> #include <stdlib.h> static uint16_t dequant_table[64]; static uint8_t requant_table[1024]; static void compute_dequant() { unsigned xmaxc, dequant, step; dequant = 0; step = 1; for (xmaxc = 0; xmaxc < 64; xmaxc++) { dequant_table[xmaxc] = dequant; dequant += step; if ((xmaxc & 7) == 7 && xmaxc != 7) step <<= 1; } } static void compute_requant() { unsigned x, c; for (x = 0; x < 1024; x++) { for (c = 0; c < 63; c++) { if (x < dequant_table[c+1]) break; } requant_table[x] = c; } } static void print_dequant() { unsigned c, r; puts("const uint16_t dequant_table[64] = {"); for (c = 0; c < 64; c++) { r = c & 7; if (!r) putchar('\t'); printf("%3u,", dequant_table[c]); if (r == 7) putchar('\n'); else putchar(' '); } fputs("};\n\n", stdout); } static void print_requant() { unsigned x, r; puts("const uint8_t requant_table[1024] = {"); for (x = 0; x < 1024; x++) { r = x & 15; if (!r) putchar('\t'); printf("%2u,", requant_table[x]); if (r == 15) putchar('\n'); else putchar(' '); } fputs("};\n", stdout); } main(argc, argv) char **argv; { compute_dequant(); compute_requant(); print_dequant(); print_requant(); exit(0); }