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
33void 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 agorithm,
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
51void 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) */
61static 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
73static 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
83void 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
93void 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 */
106static 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] << 8;      // *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] << 8;
120    }
121}
122
123void 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
145void 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
171void 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
191void 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
209void 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
228void 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