aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/celp_math.c
blob: df05917d20f870db75ff6e5605b18acb84d41c00 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
/*
 * Various fixed-point math operations
 *
 * Copyright (c) 2008 Vladimir Voroshilov
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <inttypes.h>
#include <limits.h>
#include <assert.h>

#include "avcodec.h"
#include "celp_math.h"

#ifdef G729_BITEXACT
/**
 * Cosine table: base_cos[i] = (1<<15) * cos(i*PI/64)
 */
static const int16_t base_cos[64] =
{
  32767,  32729,  32610,  32413,  32138,  31786,  31357,  30853,
  30274,  29622,  28899,  28106,  27246,  26320,  25330,  24279,
  23170,  22006,  20788,  19520,  18205,  16846,  15447,  14010,
  12540,  11039,   9512,   7962,   6393,   4808,   3212,   1608,
      0,  -1608,  -3212,  -4808,  -6393,  -7962,  -9512, -11039,
 -12540, -14010, -15447, -16846, -18205, -19520, -20788, -22006,
 -23170, -24279, -25330, -26320, -27246, -28106, -28899, -29622,
 -30274, -30853, -31357, -31786, -32138, -32413, -32610, -32729
};

/**
 * Slope used to compute cos(x)
 *
 * cos(ind*64+offset) = base_cos[ind]+offset*slope_cos[ind]
 * values multiplied by 1<<19
 */
static const int16_t slope_cos[64] =
{
   -632,  -1893,  -3150,  -4399,  -5638,  -6863,  -8072,  -9261,
 -10428, -11570, -12684, -13767, -14817, -15832, -16808, -17744,
 -18637, -19486, -20287, -21039, -21741, -22390, -22986, -23526,
 -24009, -24435, -24801, -25108, -25354, -25540, -25664, -25726,
 -25726, -25664, -25540, -25354, -25108, -24801, -24435, -24009,
 -23526, -22986, -22390, -21741, -21039, -20287, -19486, -18637,
 -17744, -16808, -15832, -14817, -13767, -12684, -11570, -10428,
  -9261,  -8072,  -6863,  -5638,  -4399,  -3150,  -1893,   -632
};

/**
 * Table used to compute exp2(x)
 *
 * tab_exp2[i] = (1<<14) * exp2(i/32) = 2^(i/32) i=0..32
 */
static const uint16_t tab_exp2[33] =
{
  16384, 16743, 17109, 17484, 17867, 18258, 18658, 19066, 19484, 19911,
  20347, 20792, 21247, 21713, 22188, 22674, 23170, 23678, 24196, 24726,
  25268, 25821, 26386, 26964, 27554, 28158, 28774, 29405, 30048, 30706,
  31379, 32066, 32767
};

int16_t ff_cos(uint16_t arg)
{
    uint8_t offset= arg;
    uint8_t ind = arg >> 8;

    assert(arg < 0x4000);

    return FFMAX(base_cos[ind] + ((slope_cos[ind] * offset) >> 12), -0x8000);
}

int ff_exp2(uint16_t power)
{
    uint16_t frac_x0;
    uint16_t frac_dx;
    int result;

    assert(power <= 0x7fff);

    frac_x0 = power >> 10;
    frac_dx = (power & 0x03ff) << 5;

    result = tab_exp2[frac_x0] << 15;
    result += frac_dx * (tab_exp2[frac_x0+1] - tab_exp2[frac_x0]);

    return result >> 10;
}

#else // G729_BITEXACT

/**
 * 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 const uint16_t exp2a[]=
{
     0,  1435,  2901,  4400,  5931,  7496,  9096, 10730,
 12400, 14106, 15850, 17632, 19454, 21315, 23216, 25160,
 27146, 29175, 31249, 33368, 35534, 37747, 40009, 42320,
 44682, 47095, 49562, 52082, 54657, 57289, 59979, 62727,
};

static const uint16_t exp2b[]=
{
     3,   712,  1424,  2134,  2845,  3557,  4270,  4982,
  5696,  6409,  7124,  7839,  8554,  9270,  9986, 10704,
 11421, 12138, 12857, 13576, 14295, 15014, 15734, 16455,
 17176, 17898, 18620, 19343, 20066, 20790, 21514, 22238,
};

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);
}

int ff_exp2(uint16_t power)
{
    unsigned int result= exp2a[power>>10] + 0x10000;

    assert(arg <= 0x7fff);

    result= (result<<3) + ((result*exp2b[(power>>5)&31])>>17);
    return result + ((result*(power&31)*89)>>22);
}

#endif // else G729_BITEXACT

/**
 * Table used to compute log2(x)
 *
 * tab_log2[i] = (1<<15) * log2(1 + i/32), i=0..32
 */
static const uint16_t tab_log2[33] =
{
#ifdef G729_BITEXACT
      0,   1455,   2866,   4236,   5568,   6863,   8124,   9352,
  10549,  11716,  12855,  13967,  15054,  16117,  17156,  18172,
  19167,  20142,  21097,  22033,  22951,  23852,  24735,  25603,
  26455,  27291,  28113,  28922,  29716,  30497,  31266,  32023,  32767,
#else
      4,   1459,   2870,   4240,   5572,   6867,   8127,   9355,
  10552,  11719,  12858,  13971,  15057,  16120,  17158,  18175,
  19170,  20145,  21100,  22036,  22954,  23854,  24738,  25605,
  26457,  27294,  28116,  28924,  29719,  30500,  31269,  32025,  32769,
#endif
};

int ff_log2(uint32_t value)
{
    uint8_t  power_int;
    uint8_t  frac_x0;
    uint16_t frac_dx;

    // Stripping zeros from beginning
    power_int = av_log2(value);
    value <<= (31 - power_int);

    // b31 is always non-zero now
    frac_x0 = (value & 0x7c000000) >> 26; // b26-b31 and [32..63] -> [0..31]
    frac_dx = (value & 0x03fff800) >> 11;

    value = tab_log2[frac_x0];
    value += (frac_dx * (tab_log2[frac_x0+1] - tab_log2[frac_x0])) >> 15;

    return (power_int << 15) + value;
}

float ff_dot_productf(const float* a, const float* b, int length)
{
    float sum = 0;
    int i;

    for(i=0; i<length; i++)
        sum += a[i] * b[i];

    return sum;
}