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author | Vladimir Voroshilov <voroshil@gmail.com> | 2008-04-25 17:14:47 +0000 |
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committer | Vladimir Voroshilov <voroshil@gmail.com> | 2008-04-25 17:14:47 +0000 |
commit | 1cf3ee2d1c13b5c22b471ac7ae08432eb357dd9f (patch) | |
tree | eb6e0ef4be4dc16ac7daf3d566ff8306e8088027 /libavcodec | |
parent | bf52a72023f92e93e6522c4d560e50ad331e2409 (diff) | |
download | ffmpeg-1cf3ee2d1c13b5c22b471ac7ae08432eb357dd9f.tar.gz |
Fixed-point implementation of ff_cos, ff_log2, ff_exp2.
Also implemented routine for calculating sum(a[i] * a[i-offset]>>shift)
Originally committed as revision 12974 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec')
-rw-r--r-- | libavcodec/acelp_math.c | 197 | ||||
-rw-r--r-- | libavcodec/acelp_math.h | 73 |
2 files changed, 270 insertions, 0 deletions
diff --git a/libavcodec/acelp_math.c b/libavcodec/acelp_math.c new file mode 100644 index 0000000000..6c8a01728f --- /dev/null +++ b/libavcodec/acelp_math.c @@ -0,0 +1,197 @@ +/* + * 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; +} diff --git a/libavcodec/acelp_math.h b/libavcodec/acelp_math.h new file mode 100644 index 0000000000..1cc36e6b49 --- /dev/null +++ b/libavcodec/acelp_math.h @@ -0,0 +1,73 @@ +/* + * 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 + */ + +#ifndef FFMPEG_ACELP_MATH_H +#define FFMPEG_ACELP_MATH_H + +/** + * \brief fixed-point implementation of cosine in [0; PI) domain + * \param arg fixed-point cosine argument, 0 <= arg < 0x4000 + * + * \return value of (1<<15) * cos(arg * PI / (1<<14)), -0x8000 <= result <= 0x7fff + */ +int16_t ff_cos(uint16_t arg); + +/** + * \brief fixed-point implementation of exp2(x) in [0; 1] domain + * \param power argument to exp2, 0 <= power <= 0x7fff + * + * \return value of (1<<20) * exp2(power / (1<<15)) + * 0x8000c <= result <= 0xfffea + */ +int ff_exp2(uint16_t power); + +/** + * \brief Calculates log2(x) + * \param value function argument, 0 < value <= 7fff ffff + * + * \return value of (1<<15) * log2(value) + */ +int ff_log2(uint32_t value); + +/** + * \brief Calculates sum of array elements multiplications + * \param speech array with input data + * \param length number elements to proceed + * \param offset offset for calculation sum of s[i]*s[i+offset] + * \param shift right shift by this value will be done before multiplication + * + * \return sum of multiplications + * + * \note array must be at least length+offset long! + */ +static int sum_of_squares(const int16_t* speech, int length, int offset, int shift) +{ + const int16_t* speech_end; + int sum = 0; + + for(speech_end=speech+length; speech<speech_end; speech++) + sum += (speech[0] * speech[offset]) >> shift; + + return sum; +} + +#endif // FFMPEG_ACELP_MATH_H |