Libav 0.7.1
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00001 /* 00002 * LSP routines for ACELP-based codecs 00003 * 00004 * Copyright (c) 2007 Reynaldo H. Verdejo Pinochet (QCELP decoder) 00005 * Copyright (c) 2008 Vladimir Voroshilov 00006 * 00007 * This file is part of Libav. 00008 * 00009 * Libav is free software; you can redistribute it and/or 00010 * modify it under the terms of the GNU Lesser General Public 00011 * License as published by the Free Software Foundation; either 00012 * version 2.1 of the License, or (at your option) any later version. 00013 * 00014 * Libav is distributed in the hope that it will be useful, 00015 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00017 * Lesser General Public License for more details. 00018 * 00019 * You should have received a copy of the GNU Lesser General Public 00020 * License along with Libav; if not, write to the Free Software 00021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00022 */ 00023 00024 #include <inttypes.h> 00025 00026 #include "avcodec.h" 00027 #define FRAC_BITS 14 00028 #include "mathops.h" 00029 #include "lsp.h" 00030 #include "celp_math.h" 00031 00032 void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsfq_min, int lsfq_max, int lp_order) 00033 { 00034 int i, j; 00035 00036 /* sort lsfq in ascending order. float bubble agorithm, 00037 O(n) if data already sorted, O(n^2) - otherwise */ 00038 for(i=0; i<lp_order-1; i++) 00039 for(j=i; j>=0 && lsfq[j] > lsfq[j+1]; j--) 00040 FFSWAP(int16_t, lsfq[j], lsfq[j+1]); 00041 00042 for(i=0; i<lp_order; i++) 00043 { 00044 lsfq[i] = FFMAX(lsfq[i], lsfq_min); 00045 lsfq_min = lsfq[i] + lsfq_min_distance; 00046 } 00047 lsfq[lp_order-1] = FFMIN(lsfq[lp_order-1], lsfq_max);//Is warning required ? 00048 } 00049 00050 void ff_set_min_dist_lsf(float *lsf, double min_spacing, int size) 00051 { 00052 int i; 00053 float prev = 0.0; 00054 for (i = 0; i < size; i++) 00055 prev = lsf[i] = FFMAX(lsf[i], prev + min_spacing); 00056 } 00057 00058 void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order) 00059 { 00060 int i; 00061 00062 /* Convert LSF to LSP, lsp=cos(lsf) */ 00063 for(i=0; i<lp_order; i++) 00064 // 20861 = 2.0 / PI in (0.15) 00065 lsp[i] = ff_cos(lsf[i] * 20861 >> 15); // divide by PI and (0,13) -> (0,14) 00066 } 00067 00068 void ff_acelp_lsf2lspd(double *lsp, const float *lsf, int lp_order) 00069 { 00070 int i; 00071 00072 for(i = 0; i < lp_order; i++) 00073 lsp[i] = cos(2.0 * M_PI * lsf[i]); 00074 } 00075 00081 static void lsp2poly(int* f, const int16_t* lsp, int lp_half_order) 00082 { 00083 int i, j; 00084 00085 f[0] = 0x400000; // 1.0 in (3.22) 00086 f[1] = -lsp[0] << 8; // *2 and (0.15) -> (3.22) 00087 00088 for(i=2; i<=lp_half_order; i++) 00089 { 00090 f[i] = f[i-2]; 00091 for(j=i; j>1; j--) 00092 f[j] -= MULL(f[j-1], lsp[2*i-2], FRAC_BITS) - f[j-2]; 00093 00094 f[1] -= lsp[2*i-2] << 8; 00095 } 00096 } 00097 00098 void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order) 00099 { 00100 int i; 00101 int f1[MAX_LP_HALF_ORDER+1]; // (3.22) 00102 int f2[MAX_LP_HALF_ORDER+1]; // (3.22) 00103 00104 lsp2poly(f1, lsp , lp_half_order); 00105 lsp2poly(f2, lsp+1, lp_half_order); 00106 00107 /* 3.2.6 of G.729, Equations 25 and 26*/ 00108 lp[0] = 4096; 00109 for(i=1; i<lp_half_order+1; i++) 00110 { 00111 int ff1 = f1[i] + f1[i-1]; // (3.22) 00112 int ff2 = f2[i] - f2[i-1]; // (3.22) 00113 00114 ff1 += 1 << 10; // for rounding 00115 lp[i] = (ff1 + ff2) >> 11; // divide by 2 and (3.22) -> (3.12) 00116 lp[(lp_half_order << 1) + 1 - i] = (ff1 - ff2) >> 11; // divide by 2 and (3.22) -> (3.12) 00117 } 00118 } 00119 00120 void ff_amrwb_lsp2lpc(const double *lsp, float *lp, int lp_order) 00121 { 00122 int lp_half_order = lp_order >> 1; 00123 double buf[lp_half_order + 1]; 00124 double pa[lp_half_order + 1]; 00125 double *qa = buf + 1; 00126 int i,j; 00127 00128 qa[-1] = 0.0; 00129 00130 ff_lsp2polyf(lsp , pa, lp_half_order ); 00131 ff_lsp2polyf(lsp + 1, qa, lp_half_order - 1); 00132 00133 for (i = 1, j = lp_order - 1; i < lp_half_order; i++, j--) { 00134 double paf = pa[i] * (1 + lsp[lp_order - 1]); 00135 double qaf = (qa[i] - qa[i-2]) * (1 - lsp[lp_order - 1]); 00136 lp[i-1] = (paf + qaf) * 0.5; 00137 lp[j-1] = (paf - qaf) * 0.5; 00138 } 00139 00140 lp[lp_half_order - 1] = (1.0 + lsp[lp_order - 1]) * 00141 pa[lp_half_order] * 0.5; 00142 00143 lp[lp_order - 1] = lsp[lp_order - 1]; 00144 } 00145 00146 void 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) 00147 { 00148 int16_t lsp_1st[MAX_LP_ORDER]; // (0.15) 00149 int i; 00150 00151 /* LSP values for first subframe (3.2.5 of G.729, Equation 24)*/ 00152 for(i=0; i<lp_order; i++) 00153 #ifdef G729_BITEXACT 00154 lsp_1st[i] = (lsp_2nd[i] >> 1) + (lsp_prev[i] >> 1); 00155 #else 00156 lsp_1st[i] = (lsp_2nd[i] + lsp_prev[i]) >> 1; 00157 #endif 00158 00159 ff_acelp_lsp2lpc(lp_1st, lsp_1st, lp_order >> 1); 00160 00161 /* LSP values for second subframe (3.2.5 of G.729)*/ 00162 ff_acelp_lsp2lpc(lp_2nd, lsp_2nd, lp_order >> 1); 00163 } 00164 00165 void ff_lsp2polyf(const double *lsp, double *f, int lp_half_order) 00166 { 00167 int i, j; 00168 00169 f[0] = 1.0; 00170 f[1] = -2 * lsp[0]; 00171 lsp -= 2; 00172 for(i=2; i<=lp_half_order; i++) 00173 { 00174 double val = -2 * lsp[2*i]; 00175 f[i] = val * f[i-1] + 2*f[i-2]; 00176 for(j=i-1; j>1; j--) 00177 f[j] += f[j-1] * val + f[j-2]; 00178 f[1] += val; 00179 } 00180 } 00181 00182 void ff_acelp_lspd2lpc(const double *lsp, float *lpc, int lp_half_order) 00183 { 00184 double pa[MAX_LP_HALF_ORDER+1], qa[MAX_LP_HALF_ORDER+1]; 00185 float *lpc2 = lpc + (lp_half_order << 1) - 1; 00186 00187 assert(lp_half_order <= MAX_LP_HALF_ORDER); 00188 00189 ff_lsp2polyf(lsp, pa, lp_half_order); 00190 ff_lsp2polyf(lsp + 1, qa, lp_half_order); 00191 00192 while (lp_half_order--) { 00193 double paf = pa[lp_half_order+1] + pa[lp_half_order]; 00194 double qaf = qa[lp_half_order+1] - qa[lp_half_order]; 00195 00196 lpc [ lp_half_order] = 0.5*(paf+qaf); 00197 lpc2[-lp_half_order] = 0.5*(paf-qaf); 00198 } 00199 } 00200 00201 void ff_sort_nearly_sorted_floats(float *vals, int len) 00202 { 00203 int i,j; 00204 00205 for (i = 0; i < len - 1; i++) 00206 for (j = i; j >= 0 && vals[j] > vals[j+1]; j--) 00207 FFSWAP(float, vals[j], vals[j+1]); 00208 }