1/* 2 * LSP routines for ACELP-based codecs 3 * 4 * Copyright (c) 2007 Reynaldo H. Verdejo Pinochet (QCELP decoder) 5 * Copyright (c) 2008 Vladimir Voroshilov 6 * 7 * This file is part of Libav. 8 * 9 * Libav is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU Lesser General Public 11 * License as published by the Free Software Foundation; either 12 * version 2.1 of the License, or (at your option) any later version. 13 * 14 * Libav is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * Lesser General Public License for more details. 18 * 19 * You should have received a copy of the GNU Lesser General Public 20 * License along with Libav; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 22 */ 23 24#include <inttypes.h> 25 26#include "avcodec.h" 27#define FRAC_BITS 14 28#include "mathops.h" 29#include "lsp.h" 30#include "celp_math.h" 31 32void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsfq_min, int lsfq_max, int lp_order) 33{ 34 int i, j; 35 36 /* sort lsfq in ascending order. float bubble agorithm, 37 O(n) if data already sorted, O(n^2) - otherwise */ 38 for(i=0; i<lp_order-1; i++) 39 for(j=i; j>=0 && lsfq[j] > lsfq[j+1]; j--) 40 FFSWAP(int16_t, lsfq[j], lsfq[j+1]); 41 42 for(i=0; i<lp_order; i++) 43 { 44 lsfq[i] = FFMAX(lsfq[i], lsfq_min); 45 lsfq_min = lsfq[i] + lsfq_min_distance; 46 } 47 lsfq[lp_order-1] = FFMIN(lsfq[lp_order-1], lsfq_max);//Is warning required ? 48} 49 50void ff_set_min_dist_lsf(float *lsf, double min_spacing, int size) 51{ 52 int i; 53 float prev = 0.0; 54 for (i = 0; i < size; i++) 55 prev = lsf[i] = FFMAX(lsf[i], prev + min_spacing); 56} 57 58void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order) 59{ 60 int i; 61 62 /* Convert LSF to LSP, lsp=cos(lsf) */ 63 for(i=0; i<lp_order; i++) 64 // 20861 = 2.0 / PI in (0.15) 65 lsp[i] = ff_cos(lsf[i] * 20861 >> 15); // divide by PI and (0,13) -> (0,14) 66} 67 68void ff_acelp_lsf2lspd(double *lsp, const float *lsf, int lp_order) 69{ 70 int i; 71 72 for(i = 0; i < lp_order; i++) 73 lsp[i] = cos(2.0 * M_PI * lsf[i]); 74} 75 76/** 77 * @brief decodes polynomial coefficients from LSP 78 * @param[out] f decoded polynomial coefficients (-0x20000000 <= (3.22) <= 0x1fffffff) 79 * @param lsp LSP coefficients (-0x8000 <= (0.15) <= 0x7fff) 80 */ 81static void lsp2poly(int* f, const int16_t* lsp, int lp_half_order) 82{ 83 int i, j; 84 85 f[0] = 0x400000; // 1.0 in (3.22) 86 f[1] = -lsp[0] << 8; // *2 and (0.15) -> (3.22) 87 88 for(i=2; i<=lp_half_order; i++) 89 { 90 f[i] = f[i-2]; 91 for(j=i; j>1; j--) 92 f[j] -= MULL(f[j-1], lsp[2*i-2], FRAC_BITS) - f[j-2]; 93 94 f[1] -= lsp[2*i-2] << 8; 95 } 96} 97 98void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order) 99{ 100 int i; 101 int f1[MAX_LP_HALF_ORDER+1]; // (3.22) 102 int f2[MAX_LP_HALF_ORDER+1]; // (3.22) 103 104 lsp2poly(f1, lsp , lp_half_order); 105 lsp2poly(f2, lsp+1, lp_half_order); 106 107 /* 3.2.6 of G.729, Equations 25 and 26*/ 108 lp[0] = 4096; 109 for(i=1; i<lp_half_order+1; i++) 110 { 111 int ff1 = f1[i] + f1[i-1]; // (3.22) 112 int ff2 = f2[i] - f2[i-1]; // (3.22) 113 114 ff1 += 1 << 10; // for rounding 115 lp[i] = (ff1 + ff2) >> 11; // divide by 2 and (3.22) -> (3.12) 116 lp[(lp_half_order << 1) + 1 - i] = (ff1 - ff2) >> 11; // divide by 2 and (3.22) -> (3.12) 117 } 118} 119 120void ff_amrwb_lsp2lpc(const double *lsp, float *lp, int lp_order) 121{ 122 int lp_half_order = lp_order >> 1; 123 double buf[MAX_LP_HALF_ORDER + 1]; 124 double pa[MAX_LP_HALF_ORDER + 1]; 125 double *qa = buf + 1; 126 int i,j; 127 128 qa[-1] = 0.0; 129 130 ff_lsp2polyf(lsp , pa, lp_half_order ); 131 ff_lsp2polyf(lsp + 1, qa, lp_half_order - 1); 132 133 for (i = 1, j = lp_order - 1; i < lp_half_order; i++, j--) { 134 double paf = pa[i] * (1 + lsp[lp_order - 1]); 135 double qaf = (qa[i] - qa[i-2]) * (1 - lsp[lp_order - 1]); 136 lp[i-1] = (paf + qaf) * 0.5; 137 lp[j-1] = (paf - qaf) * 0.5; 138 } 139 140 lp[lp_half_order - 1] = (1.0 + lsp[lp_order - 1]) * 141 pa[lp_half_order] * 0.5; 142 143 lp[lp_order - 1] = lsp[lp_order - 1]; 144} 145 146void ff_acelp_lp_decode(int16_t* lp_1st, int16_t* lp_2nd, const int16_t* lsp_2nd, const int16_t* lsp_prev, int lp_order) 147{ 148 int16_t lsp_1st[MAX_LP_ORDER]; // (0.15) 149 int i; 150 151 /* LSP values for first subframe (3.2.5 of G.729, Equation 24)*/ 152 for(i=0; i<lp_order; i++) 153 lsp_1st[i] = (lsp_2nd[i] + lsp_prev[i]) >> 1; 154 155 ff_acelp_lsp2lpc(lp_1st, lsp_1st, lp_order >> 1); 156 157 /* LSP values for second subframe (3.2.5 of G.729)*/ 158 ff_acelp_lsp2lpc(lp_2nd, lsp_2nd, lp_order >> 1); 159} 160 161void ff_lsp2polyf(const double *lsp, double *f, int lp_half_order) 162{ 163 int i, j; 164 165 f[0] = 1.0; 166 f[1] = -2 * lsp[0]; 167 lsp -= 2; 168 for(i=2; i<=lp_half_order; i++) 169 { 170 double val = -2 * lsp[2*i]; 171 f[i] = val * f[i-1] + 2*f[i-2]; 172 for(j=i-1; j>1; j--) 173 f[j] += f[j-1] * val + f[j-2]; 174 f[1] += val; 175 } 176} 177 178void ff_acelp_lspd2lpc(const double *lsp, float *lpc, int lp_half_order) 179{ 180 double pa[MAX_LP_HALF_ORDER+1], qa[MAX_LP_HALF_ORDER+1]; 181 float *lpc2 = lpc + (lp_half_order << 1) - 1; 182 183 assert(lp_half_order <= MAX_LP_HALF_ORDER); 184 185 ff_lsp2polyf(lsp, pa, lp_half_order); 186 ff_lsp2polyf(lsp + 1, qa, lp_half_order); 187 188 while (lp_half_order--) { 189 double paf = pa[lp_half_order+1] + pa[lp_half_order]; 190 double qaf = qa[lp_half_order+1] - qa[lp_half_order]; 191 192 lpc [ lp_half_order] = 0.5*(paf+qaf); 193 lpc2[-lp_half_order] = 0.5*(paf-qaf); 194 } 195} 196 197void ff_sort_nearly_sorted_floats(float *vals, int len) 198{ 199 int i,j; 200 201 for (i = 0; i < len - 1; i++) 202 for (j = i; j >= 0 && vals[j] > vals[j+1]; j--) 203 FFSWAP(float, vals[j], vals[j+1]); 204} 205