/* * LSP routines for ACELP-based codecs * * Copyright (c) 2007 Reynaldo H. Verdejo Pinochet (QCELP decoder) * Copyright (c) 2008 Vladimir Voroshilov * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include <inttypes.h> #include "avcodec.h" #define FRAC_BITS 14 #include "mathops.h" #include "lsp.h" void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsfq_min, int lsfq_max, int lp_order) { int i, j; /* sort lsfq in ascending order. float bubble agorithm, O(n) if data already sorted, O(n^2) - otherwise */ for(i=0; i<lp_order-1; i++) for(j=i; j>=0 && lsfq[j] > lsfq[j+1]; j--) FFSWAP(int16_t, lsfq[j], lsfq[j+1]); for(i=0; i<lp_order; i++) { lsfq[i] = FFMAX(lsfq[i], lsfq_min); lsfq_min = lsfq[i] + lsfq_min_distance; } lsfq[lp_order-1] = FFMIN(lsfq[lp_order-1], lsfq_max);//Is warning required ? } void ff_set_min_dist_lsf(float *lsf, double min_spacing, int size) { int i; float prev = 0.0; for (i = 0; i < size; i++) prev = lsf[i] = FFMAX(lsf[i], prev + min_spacing); } /* Cosine table: base_cos[i] = (1 << 15) * cos(i * PI / 64) */ static const int16_t tab_cos[65] = { 32767, 32738, 32617, 32421, 32145, 31793, 31364, 30860, 30280, 29629, 28905, 28113, 27252, 26326, 25336, 24285, 23176, 22011, 20793, 19525, 18210, 16851, 15451, 14014, 12543, 11043, 9515, 7965, 6395, 4810, 3214, 1609, 1, -1607, -3211, -4808, -6393, -7962, -9513, -11040, -12541, -14012, -15449, -16848, -18207, -19523, -20791, -22009, -23174, -24283, -25334, -26324, -27250, -28111, -28904, -29627, -30279, -30858, -31363, -31792, -32144, -32419, -32616, -32736, -32768, }; static int16_t ff_cos(uint16_t arg) { uint8_t offset= arg; uint8_t ind = arg >> 8; assert(arg <= 0x3fff); return tab_cos[ind] + (offset * (tab_cos[ind+1] - tab_cos[ind]) >> 8); } void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order) { int i; /* Convert LSF to LSP, lsp=cos(lsf) */ for(i=0; i<lp_order; i++) // 20861 = 2.0 / PI in (0.15) lsp[i] = ff_cos(lsf[i] * 20861 >> 15); // divide by PI and (0,13) -> (0,14) } void ff_acelp_lsf2lspd(double *lsp, const float *lsf, int lp_order) { int i; for(i = 0; i < lp_order; i++) lsp[i] = cos(2.0 * M_PI * lsf[i]); } /** * @brief decodes polynomial coefficients from LSP * @param[out] f decoded polynomial coefficients (-0x20000000 <= (3.22) <= 0x1fffffff) * @param lsp LSP coefficients (-0x8000 <= (0.15) <= 0x7fff) */ static void lsp2poly(int* f, const int16_t* lsp, int lp_half_order) { int i, j; f[0] = 0x400000; // 1.0 in (3.22) f[1] = -lsp[0] << 8; // *2 and (0.15) -> (3.22) for(i=2; i<=lp_half_order; i++) { f[i] = f[i-2]; for(j=i; j>1; j--) f[j] -= MULL(f[j-1], lsp[2*i-2], FRAC_BITS) - f[j-2]; f[1] -= lsp[2*i-2] << 8; } } void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order) { int i; int f1[MAX_LP_HALF_ORDER+1]; // (3.22) int f2[MAX_LP_HALF_ORDER+1]; // (3.22) lsp2poly(f1, lsp , lp_half_order); lsp2poly(f2, lsp+1, lp_half_order); /* 3.2.6 of G.729, Equations 25 and 26*/ lp[0] = 4096; for(i=1; i<lp_half_order+1; i++) { int ff1 = f1[i] + f1[i-1]; // (3.22) int ff2 = f2[i] - f2[i-1]; // (3.22) ff1 += 1 << 10; // for rounding lp[i] = (ff1 + ff2) >> 11; // divide by 2 and (3.22) -> (3.12) lp[(lp_half_order << 1) + 1 - i] = (ff1 - ff2) >> 11; // divide by 2 and (3.22) -> (3.12) } } void ff_amrwb_lsp2lpc(const double *lsp, float *lp, int lp_order) { int lp_half_order = lp_order >> 1; double buf[MAX_LP_HALF_ORDER + 1]; double pa[MAX_LP_HALF_ORDER + 1]; double *qa = buf + 1; int i,j; qa[-1] = 0.0; ff_lsp2polyf(lsp , pa, lp_half_order ); ff_lsp2polyf(lsp + 1, qa, lp_half_order - 1); for (i = 1, j = lp_order - 1; i < lp_half_order; i++, j--) { double paf = pa[i] * (1 + lsp[lp_order - 1]); double qaf = (qa[i] - qa[i-2]) * (1 - lsp[lp_order - 1]); lp[i-1] = (paf + qaf) * 0.5; lp[j-1] = (paf - qaf) * 0.5; } lp[lp_half_order - 1] = (1.0 + lsp[lp_order - 1]) * pa[lp_half_order] * 0.5; lp[lp_order - 1] = lsp[lp_order - 1]; } 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) { int16_t lsp_1st[MAX_LP_ORDER]; // (0.15) int i; /* LSP values for first subframe (3.2.5 of G.729, Equation 24)*/ for(i=0; i<lp_order; i++) lsp_1st[i] = (lsp_2nd[i] + lsp_prev[i]) >> 1; ff_acelp_lsp2lpc(lp_1st, lsp_1st, lp_order >> 1); /* LSP values for second subframe (3.2.5 of G.729)*/ ff_acelp_lsp2lpc(lp_2nd, lsp_2nd, lp_order >> 1); } void ff_lsp2polyf(const double *lsp, double *f, int lp_half_order) { int i, j; f[0] = 1.0; f[1] = -2 * lsp[0]; lsp -= 2; for(i=2; i<=lp_half_order; i++) { double val = -2 * lsp[2*i]; f[i] = val * f[i-1] + 2*f[i-2]; for(j=i-1; j>1; j--) f[j] += f[j-1] * val + f[j-2]; f[1] += val; } } void ff_acelp_lspd2lpc(const double *lsp, float *lpc, int lp_half_order) { double pa[MAX_LP_HALF_ORDER+1], qa[MAX_LP_HALF_ORDER+1]; float *lpc2 = lpc + (lp_half_order << 1) - 1; assert(lp_half_order <= MAX_LP_HALF_ORDER); ff_lsp2polyf(lsp, pa, lp_half_order); ff_lsp2polyf(lsp + 1, qa, lp_half_order); while (lp_half_order--) { double paf = pa[lp_half_order+1] + pa[lp_half_order]; double qaf = qa[lp_half_order+1] - qa[lp_half_order]; lpc [ lp_half_order] = 0.5*(paf+qaf); lpc2[-lp_half_order] = 0.5*(paf-qaf); } } void ff_sort_nearly_sorted_floats(float *vals, int len) { int i,j; for (i = 0; i < len - 1; i++) for (j = i; j >= 0 && vals[j] > vals[j+1]; j--) FFSWAP(float, vals[j], vals[j+1]); }