mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-23 12:43:46 +02:00
1cf3ee2d1c
Also implemented routine for calculating sum(a[i] * a[i-offset]>>shift) Originally committed as revision 12974 to svn://svn.ffmpeg.org/ffmpeg/trunk
198 lines
5.9 KiB
C
198 lines
5.9 KiB
C
/*
|
|
* 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 "acelp_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;
|
|
}
|