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123 lines
3.5 KiB
123 lines
3.5 KiB
/* |
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* Various fixed-point math operations |
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* |
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* Copyright (c) 2008 Vladimir Voroshilov |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include <inttypes.h> |
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#include <limits.h> |
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#include <assert.h> |
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#include "avcodec.h" |
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#include "celp_math.h" |
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/** |
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* Cosine table: base_cos[i] = (1<<15) * cos(i*PI/64) |
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*/ |
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static const int16_t tab_cos[65] = |
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{ |
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32767, 32738, 32617, 32421, 32145, 31793, 31364, 30860, |
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30280, 29629, 28905, 28113, 27252, 26326, 25336, 24285, |
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23176, 22011, 20793, 19525, 18210, 16851, 15451, 14014, |
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12543, 11043, 9515, 7965, 6395, 4810, 3214, 1609, |
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1, -1607, -3211, -4808, -6393, -7962, -9513, -11040, |
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-12541, -14012, -15449, -16848, -18207, -19523, -20791, -22009, |
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-23174, -24283, -25334, -26324, -27250, -28111, -28904, -29627, |
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-30279, -30858, -31363, -31792, -32144, -32419, -32616, -32736, -32768, |
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}; |
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static const uint16_t exp2a[]= |
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{ |
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0, 1435, 2901, 4400, 5931, 7496, 9096, 10730, |
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12400, 14106, 15850, 17632, 19454, 21315, 23216, 25160, |
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27146, 29175, 31249, 33368, 35534, 37747, 40009, 42320, |
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44682, 47095, 49562, 52082, 54657, 57289, 59979, 62727, |
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}; |
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static const uint16_t exp2b[]= |
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{ |
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3, 712, 1424, 2134, 2845, 3557, 4270, 4982, |
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5696, 6409, 7124, 7839, 8554, 9270, 9986, 10704, |
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11421, 12138, 12857, 13576, 14295, 15014, 15734, 16455, |
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17176, 17898, 18620, 19343, 20066, 20790, 21514, 22238, |
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}; |
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int16_t ff_cos(uint16_t arg) |
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{ |
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uint8_t offset= arg; |
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uint8_t ind = arg >> 8; |
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assert(arg <= 0x3fff); |
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return tab_cos[ind] + (offset * (tab_cos[ind+1] - tab_cos[ind]) >> 8); |
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} |
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int ff_exp2(uint16_t power) |
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{ |
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unsigned int result= exp2a[power>>10] + 0x10000; |
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assert(power <= 0x7fff); |
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result= (result<<3) + ((result*exp2b[(power>>5)&31])>>17); |
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return result + ((result*(power&31)*89)>>22); |
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} |
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/** |
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* Table used to compute log2(x) |
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* |
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* tab_log2[i] = (1<<15) * log2(1 + i/32), i=0..32 |
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*/ |
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static const uint16_t tab_log2[33] = |
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{ |
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4, 1459, 2870, 4240, 5572, 6867, 8127, 9355, |
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10552, 11719, 12858, 13971, 15057, 16120, 17158, 18175, |
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19170, 20145, 21100, 22036, 22954, 23854, 24738, 25605, |
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26457, 27294, 28116, 28924, 29719, 30500, 31269, 32025, 32769, |
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}; |
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int ff_log2(uint32_t value) |
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{ |
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uint8_t power_int; |
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uint8_t frac_x0; |
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uint16_t frac_dx; |
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// Stripping zeros from beginning |
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power_int = av_log2(value); |
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value <<= (31 - power_int); |
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// b31 is always non-zero now |
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frac_x0 = (value & 0x7c000000) >> 26; // b26-b31 and [32..63] -> [0..31] |
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frac_dx = (value & 0x03fff800) >> 11; |
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value = tab_log2[frac_x0]; |
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value += (frac_dx * (tab_log2[frac_x0+1] - tab_log2[frac_x0])) >> 15; |
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return (power_int << 15) + value; |
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} |
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float ff_dot_productf(const float* a, const float* b, int length) |
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{ |
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float sum = 0; |
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int i; |
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for(i=0; i<length; i++) |
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sum += a[i] * b[i]; |
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return sum; |
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}
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