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 "libavcodec/mips/lsp_mips.h"
31 #include "libavutil/avassert.h"
32
ff_acelp_reorder_lsf(int16_t * lsfq,int lsfq_min_distance,int lsfq_min,int lsfq_max,int lp_order)33 void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsfq_min, int lsfq_max, int lp_order)
34 {
35 int i, j;
36
37 /* sort lsfq in ascending order. float bubble algorithm,
38 O(n) if data already sorted, O(n^2) - otherwise */
39 for(i=0; i<lp_order-1; i++)
40 for(j=i; j>=0 && lsfq[j] > lsfq[j+1]; j--)
41 FFSWAP(int16_t, lsfq[j], lsfq[j+1]);
42
43 for(i=0; i<lp_order; i++)
44 {
45 lsfq[i] = FFMAX(lsfq[i], lsfq_min);
46 lsfq_min = lsfq[i] + lsfq_min_distance;
47 }
48 lsfq[lp_order-1] = FFMIN(lsfq[lp_order-1], lsfq_max);//Is warning required ?
49 }
50
ff_set_min_dist_lsf(float * lsf,double min_spacing,int size)51 void ff_set_min_dist_lsf(float *lsf, double min_spacing, int size)
52 {
53 int i;
54 float prev = 0.0;
55 for (i = 0; i < size; i++)
56 prev = lsf[i] = FFMAX(lsf[i], prev + min_spacing);
57 }
58
59
60 /* Cosine table: base_cos[i] = (1 << 15) * cos(i * PI / 64) */
61 static const int16_t tab_cos[65] =
62 {
63 32767, 32738, 32617, 32421, 32145, 31793, 31364, 30860,
64 30280, 29629, 28905, 28113, 27252, 26326, 25336, 24285,
65 23176, 22011, 20793, 19525, 18210, 16851, 15451, 14014,
66 12543, 11043, 9515, 7965, 6395, 4810, 3214, 1609,
67 1, -1607, -3211, -4808, -6393, -7962, -9513, -11040,
68 -12541, -14012, -15449, -16848, -18207, -19523, -20791, -22009,
69 -23174, -24283, -25334, -26324, -27250, -28111, -28904, -29627,
70 -30279, -30858, -31363, -31792, -32144, -32419, -32616, -32736, -32768,
71 };
72
ff_cos(uint16_t arg)73 static int16_t ff_cos(uint16_t arg)
74 {
75 uint8_t offset= arg;
76 uint8_t ind = arg >> 8;
77
78 av_assert2(arg <= 0x3fff);
79
80 return tab_cos[ind] + (offset * (tab_cos[ind+1] - tab_cos[ind]) >> 8);
81 }
82
ff_acelp_lsf2lsp(int16_t * lsp,const int16_t * lsf,int lp_order)83 void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order)
84 {
85 int i;
86
87 /* Convert LSF to LSP, lsp=cos(lsf) */
88 for(i=0; i<lp_order; i++)
89 // 20861 = 2.0 / PI in (0.15)
90 lsp[i] = ff_cos(lsf[i] * 20861 >> 15); // divide by PI and (0,13) -> (0,14)
91 }
92
ff_acelp_lsf2lspd(double * lsp,const float * lsf,int lp_order)93 void ff_acelp_lsf2lspd(double *lsp, const float *lsf, int lp_order)
94 {
95 int i;
96
97 for(i = 0; i < lp_order; i++)
98 lsp[i] = cos(2.0 * M_PI * lsf[i]);
99 }
100
101 /**
102 * @brief decodes polynomial coefficients from LSP
103 * @param[out] f decoded polynomial coefficients (-0x20000000 <= (3.22) <= 0x1fffffff)
104 * @param lsp LSP coefficients (-0x8000 <= (0.15) <= 0x7fff)
105 */
lsp2poly(int * f,const int16_t * lsp,int lp_half_order)106 static void lsp2poly(int* f, const int16_t* lsp, int lp_half_order)
107 {
108 int i, j;
109
110 f[0] = 0x400000; // 1.0 in (3.22)
111 f[1] = -lsp[0] * 256; // *2 and (0.15) -> (3.22)
112
113 for(i=2; i<=lp_half_order; i++)
114 {
115 f[i] = f[i-2];
116 for(j=i; j>1; j--)
117 f[j] -= MULL(f[j-1], lsp[2*i-2], FRAC_BITS) - f[j-2];
118
119 f[1] -= lsp[2*i-2] * 256;
120 }
121 }
122
ff_acelp_lsp2lpc(int16_t * lp,const int16_t * lsp,int lp_half_order)123 void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order)
124 {
125 int i;
126 int f1[MAX_LP_HALF_ORDER+1]; // (3.22)
127 int f2[MAX_LP_HALF_ORDER+1]; // (3.22)
128
129 lsp2poly(f1, lsp , lp_half_order);
130 lsp2poly(f2, lsp+1, lp_half_order);
131
132 /* 3.2.6 of G.729, Equations 25 and 26*/
133 lp[0] = 4096;
134 for(i=1; i<lp_half_order+1; i++)
135 {
136 int ff1 = f1[i] + f1[i-1]; // (3.22)
137 int ff2 = f2[i] - f2[i-1]; // (3.22)
138
139 ff1 += 1 << 10; // for rounding
140 lp[i] = (ff1 + ff2) >> 11; // divide by 2 and (3.22) -> (3.12)
141 lp[(lp_half_order << 1) + 1 - i] = (ff1 - ff2) >> 11; // divide by 2 and (3.22) -> (3.12)
142 }
143 }
144
ff_amrwb_lsp2lpc(const double * lsp,float * lp,int lp_order)145 void ff_amrwb_lsp2lpc(const double *lsp, float *lp, int lp_order)
146 {
147 int lp_half_order = lp_order >> 1;
148 double buf[MAX_LP_HALF_ORDER + 1];
149 double pa[MAX_LP_HALF_ORDER + 1];
150 double *qa = buf + 1;
151 int i,j;
152
153 qa[-1] = 0.0;
154
155 ff_lsp2polyf(lsp , pa, lp_half_order );
156 ff_lsp2polyf(lsp + 1, qa, lp_half_order - 1);
157
158 for (i = 1, j = lp_order - 1; i < lp_half_order; i++, j--) {
159 double paf = pa[i] * (1 + lsp[lp_order - 1]);
160 double qaf = (qa[i] - qa[i-2]) * (1 - lsp[lp_order - 1]);
161 lp[i-1] = (paf + qaf) * 0.5;
162 lp[j-1] = (paf - qaf) * 0.5;
163 }
164
165 lp[lp_half_order - 1] = (1.0 + lsp[lp_order - 1]) *
166 pa[lp_half_order] * 0.5;
167
168 lp[lp_order - 1] = lsp[lp_order - 1];
169 }
170
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)171 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)
172 {
173 int16_t lsp_1st[MAX_LP_ORDER]; // (0.15)
174 int i;
175
176 /* LSP values for first subframe (3.2.5 of G.729, Equation 24)*/
177 for(i=0; i<lp_order; i++)
178 #ifdef G729_BITEXACT
179 lsp_1st[i] = (lsp_2nd[i] >> 1) + (lsp_prev[i] >> 1);
180 #else
181 lsp_1st[i] = (lsp_2nd[i] + lsp_prev[i]) >> 1;
182 #endif
183
184 ff_acelp_lsp2lpc(lp_1st, lsp_1st, lp_order >> 1);
185
186 /* LSP values for second subframe (3.2.5 of G.729)*/
187 ff_acelp_lsp2lpc(lp_2nd, lsp_2nd, lp_order >> 1);
188 }
189
190 #ifndef ff_lsp2polyf
ff_lsp2polyf(const double * lsp,double * f,int lp_half_order)191 void ff_lsp2polyf(const double *lsp, double *f, int lp_half_order)
192 {
193 int i, j;
194
195 f[0] = 1.0;
196 f[1] = -2 * lsp[0];
197 lsp -= 2;
198 for(i=2; i<=lp_half_order; i++)
199 {
200 double val = -2 * lsp[2*i];
201 f[i] = val * f[i-1] + 2*f[i-2];
202 for(j=i-1; j>1; j--)
203 f[j] += f[j-1] * val + f[j-2];
204 f[1] += val;
205 }
206 }
207 #endif /* ff_lsp2polyf */
208
ff_acelp_lspd2lpc(const double * lsp,float * lpc,int lp_half_order)209 void ff_acelp_lspd2lpc(const double *lsp, float *lpc, int lp_half_order)
210 {
211 double pa[MAX_LP_HALF_ORDER+1], qa[MAX_LP_HALF_ORDER+1];
212 float *lpc2 = lpc + (lp_half_order << 1) - 1;
213
214 av_assert2(lp_half_order <= MAX_LP_HALF_ORDER);
215
216 ff_lsp2polyf(lsp, pa, lp_half_order);
217 ff_lsp2polyf(lsp + 1, qa, lp_half_order);
218
219 while (lp_half_order--) {
220 double paf = pa[lp_half_order+1] + pa[lp_half_order];
221 double qaf = qa[lp_half_order+1] - qa[lp_half_order];
222
223 lpc [ lp_half_order] = 0.5*(paf+qaf);
224 lpc2[-lp_half_order] = 0.5*(paf-qaf);
225 }
226 }
227
ff_sort_nearly_sorted_floats(float * vals,int len)228 void ff_sort_nearly_sorted_floats(float *vals, int len)
229 {
230 int i,j;
231
232 for (i = 0; i < len - 1; i++)
233 for (j = i; j >= 0 && vals[j] > vals[j+1]; j--)
234 FFSWAP(float, vals[j], vals[j+1]);
235 }
236