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[libav.git] / libavcodec / lsp.c
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
32 void 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
50 void 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
58 void 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 void 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 */
81 static 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
98 void 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
120 void 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
146 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)
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
161 void 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
178 void 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
197 void 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 }