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 FFmpeg. 8 * 9 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 68/** 69 * \brief decodes polynomial coefficients from LSP 70 * \param f [out] decoded polynomial coefficients (-0x20000000 <= (3.22) <= 0x1fffffff) 71 * \param lsp LSP coefficients (-0x8000 <= (0.15) <= 0x7fff) 72 */ 73static void lsp2poly(int* f, const int16_t* lsp, int lp_half_order) 74{ 75 int i, j; 76 77 f[0] = 0x400000; // 1.0 in (3.22) 78 f[1] = -lsp[0] << 8; // *2 and (0.15) -> (3.22) 79 80 for(i=2; i<=lp_half_order; i++) 81 { 82 f[i] = f[i-2]; 83 for(j=i; j>1; j--) 84 f[j] -= MULL(f[j-1], lsp[2*i-2], FRAC_BITS) - f[j-2]; 85 86 f[1] -= lsp[2*i-2] << 8; 87 } 88} 89 90void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order) 91{ 92 int i; 93 int f1[lp_half_order+1]; // (3.22) 94 int f2[lp_half_order+1]; // (3.22) 95 96 lsp2poly(f1, lsp , lp_half_order); 97 lsp2poly(f2, lsp+1, lp_half_order); 98 99 /* 3.2.6 of G.729, Equations 25 and 26*/ 100 lp[0] = 4096; 101 for(i=1; i<lp_half_order+1; i++) 102 { 103 int ff1 = f1[i] + f1[i-1]; // (3.22) 104 int ff2 = f2[i] - f2[i-1]; // (3.22) 105 106 ff1 += 1 << 10; // for rounding 107 lp[i] = (ff1 + ff2) >> 11; // divide by 2 and (3.22) -> (3.12) 108 lp[(lp_half_order << 1) + 1 - i] = (ff1 - ff2) >> 11; // divide by 2 and (3.22) -> (3.12) 109 } 110} 111 112void 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) 113{ 114 int16_t lsp_1st[lp_order]; // (0.15) 115 int i; 116 117 /* LSP values for first subframe (3.2.5 of G.729, Equation 24)*/ 118 for(i=0; i<lp_order; i++) 119#ifdef G729_BITEXACT 120 lsp_1st[i] = (lsp_2nd[i] >> 1) + (lsp_prev[i] >> 1); 121#else 122 lsp_1st[i] = (lsp_2nd[i] + lsp_prev[i]) >> 1; 123#endif 124 125 ff_acelp_lsp2lpc(lp_1st, lsp_1st, lp_order >> 1); 126 127 /* LSP values for second subframe (3.2.5 of G.729)*/ 128 ff_acelp_lsp2lpc(lp_2nd, lsp_2nd, lp_order >> 1); 129} 130 131void ff_lsp2polyf(const double *lsp, double *f, int lp_half_order) 132{ 133 int i, j; 134 135 f[0] = 1.0; 136 f[1] = -2 * lsp[0]; 137 lsp -= 2; 138 for(i=2; i<=lp_half_order; i++) 139 { 140 double val = -2 * lsp[2*i]; 141 f[i] = val * f[i-1] + 2*f[i-2]; 142 for(j=i-1; j>1; j--) 143 f[j] += f[j-1] * val + f[j-2]; 144 f[1] += val; 145 } 146} 147 148void ff_acelp_lspd2lpc(const double *lsp, float *lpc, int lp_half_order) 149{ 150 double pa[MAX_LP_HALF_ORDER+1], qa[MAX_LP_HALF_ORDER+1]; 151 float *lpc2 = lpc + (lp_half_order << 1) - 1; 152 153 assert(lp_half_order <= MAX_LP_HALF_ORDER); 154 155 ff_lsp2polyf(lsp, pa, lp_half_order); 156 ff_lsp2polyf(lsp + 1, qa, lp_half_order); 157 158 while (lp_half_order--) { 159 double paf = pa[lp_half_order+1] + pa[lp_half_order]; 160 double qaf = qa[lp_half_order+1] - qa[lp_half_order]; 161 162 lpc [ lp_half_order] = 0.5*(paf+qaf); 163 lpc2[-lp_half_order] = 0.5*(paf-qaf); 164 } 165} 166 167void ff_sort_nearly_sorted_floats(float *vals, int len) 168{ 169 int i,j; 170 171 for (i = 0; i < len - 1; i++) 172 for (j = i; j >= 0 && vals[j] > vals[j+1]; j--) 173 FFSWAP(float, vals[j], vals[j+1]); 174} 175