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ffmpeg/libavcodec/aactab.h
Marton Balint 67bef4cffa avcodec/aactab: do not use floats for constants 
This may improve the precision of the fixed point encoder/decoder for some
compilers and architectures.

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Marton Balint <cus@passwd.hu>
2016-03-15 00:47:38 +01:00

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/*
* AAC data declarations
* Copyright (c) 2005-2006 Oded Shimon ( ods15 ods15 dyndns org )
* Copyright (c) 2006-2007 Maxim Gavrilov ( maxim.gavrilov gmail com )
*
* 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
*/
/**
* @file
* AAC data declarations
* @author Oded Shimon ( ods15 ods15 dyndns org )
* @author Maxim Gavrilov ( maxim.gavrilov gmail com )
*/
#ifndef AVCODEC_AACTAB_H
#define AVCODEC_AACTAB_H
#include "libavutil/mem.h"
#include "aac.h"
#include <stdint.h>
/* NOTE:
* Tables in this file are shared by the AAC decoders and encoder
*/
extern float ff_aac_pow2sf_tab[428];
extern float ff_aac_pow34sf_tab[428];
static inline void ff_aac_tableinit(void)
{
int i;
/* 2^(i/16) for 0 <= i <= 15 */
static const float exp2_lut[] = {
1.00000000000000000000,
1.04427378242741384032,
1.09050773266525765921,
1.13878863475669165370,
1.18920711500272106672,
1.24185781207348404859,
1.29683955465100966593,
1.35425554693689272830,
1.41421356237309504880,
1.47682614593949931139,
1.54221082540794082361,
1.61049033194925430818,
1.68179283050742908606,
1.75625216037329948311,
1.83400808640934246349,
1.91520656139714729387,
};
float t1 = 8.8817841970012523233890533447265625e-16; // 2^(-50)
float t2 = 3.63797880709171295166015625e-12; // 2^(-38)
int t1_inc_cur, t2_inc_cur;
int t1_inc_prev = 0;
int t2_inc_prev = 8;
for (i = 0; i < 428; i++) {
t1_inc_cur = 4 * (i % 4);
t2_inc_cur = (8 + 3*i) % 16;
if (t1_inc_cur < t1_inc_prev)
t1 *= 2;
if (t2_inc_cur < t2_inc_prev)
t2 *= 2;
// A much more efficient and accurate way of doing:
// ff_aac_pow2sf_tab[i] = pow(2, (i - POW_SF2_ZERO) / 4.0);
// ff_aac_pow34sf_tab[i] = pow(ff_aac_pow2sf_tab[i], 3.0/4.0);
ff_aac_pow2sf_tab[i] = t1 * exp2_lut[t1_inc_cur];
ff_aac_pow34sf_tab[i] = t2 * exp2_lut[t2_inc_cur];
t1_inc_prev = t1_inc_cur;
t2_inc_prev = t2_inc_cur;
}
}
/* @name ltp_coef
* Table of the LTP coefficients
*/
static const INTFLOAT ltp_coef[8] = {
Q30(0.570829), Q30(0.696616), Q30(0.813004), Q30(0.911304),
Q30(0.984900), Q30(1.067894), Q30(1.194601), Q30(1.369533),
};
/* @name tns_tmp2_map
* Tables of the tmp2[] arrays of LPC coefficients used for TNS.
* The suffix _M_N[] indicate the values of coef_compress and coef_res
* respectively.
* @{
*/
static const INTFLOAT tns_tmp2_map_1_3[4] = {
Q31(0.00000000), Q31(-0.43388373), Q31(0.64278758), Q31(0.34202015),
};
static const INTFLOAT tns_tmp2_map_0_3[8] = {
Q31(0.00000000), Q31(-0.43388373), Q31(-0.78183150), Q31(-0.97492790),
Q31(0.98480773), Q31( 0.86602539), Q31( 0.64278758), Q31( 0.34202015),
};
static const INTFLOAT tns_tmp2_map_1_4[8] = {
Q31(0.00000000), Q31(-0.20791170), Q31(-0.40673664), Q31(-0.58778524),
Q31(0.67369562), Q31( 0.52643216), Q31( 0.36124167), Q31( 0.18374951),
};
static const INTFLOAT tns_tmp2_map_0_4[16] = {
Q31( 0.00000000), Q31(-0.20791170), Q31(-0.40673664), Q31(-0.58778524),
Q31(-0.74314481), Q31(-0.86602539), Q31(-0.95105654), Q31(-0.99452192),
Q31( 0.99573416), Q31( 0.96182561), Q31( 0.89516330), Q31( 0.79801720),
Q31( 0.67369562), Q31( 0.52643216), Q31( 0.36124167), Q31( 0.18374951),
};
static const INTFLOAT * const tns_tmp2_map[4] = {
tns_tmp2_map_0_3,
tns_tmp2_map_0_4,
tns_tmp2_map_1_3,
tns_tmp2_map_1_4
};
// @}
/* @name window coefficients
* @{
*/
DECLARE_ALIGNED(32, extern float, ff_aac_kbd_long_1024)[1024];
DECLARE_ALIGNED(32, extern float, ff_aac_kbd_short_128)[128];
DECLARE_ALIGNED(32, extern int, ff_aac_kbd_long_1024_fixed)[1024];
DECLARE_ALIGNED(32, extern int, ff_aac_kbd_long_512_fixed)[512];
DECLARE_ALIGNED(32, extern int, ff_aac_kbd_short_128_fixed)[128];
const DECLARE_ALIGNED(32, extern float, ff_aac_eld_window_512)[1920];
const DECLARE_ALIGNED(32, extern int, ff_aac_eld_window_512_fixed)[1920];
const DECLARE_ALIGNED(32, extern float, ff_aac_eld_window_480)[1800];
const DECLARE_ALIGNED(32, extern int, ff_aac_eld_window_480_fixed)[1800];
// @}
/* @name number of scalefactor window bands for long and short transform windows respectively
* @{
*/
extern const uint8_t ff_aac_num_swb_1024[];
extern const uint8_t ff_aac_num_swb_512 [];
extern const uint8_t ff_aac_num_swb_480 [];
extern const uint8_t ff_aac_num_swb_128 [];
// @}
extern const uint8_t ff_aac_pred_sfb_max [];
extern const uint32_t ff_aac_scalefactor_code[121];
extern const uint8_t ff_aac_scalefactor_bits[121];
extern const uint16_t * const ff_aac_spectral_codes[11];
extern const uint8_t * const ff_aac_spectral_bits [11];
extern const uint16_t ff_aac_spectral_sizes[11];
extern const float *ff_aac_codebook_vectors[];
extern const float *ff_aac_codebook_vector_vals[];
extern const uint16_t *ff_aac_codebook_vector_idx[];
extern const uint16_t * const ff_swb_offset_1024[13];
extern const uint16_t * const ff_swb_offset_512 [13];
extern const uint16_t * const ff_swb_offset_480 [13];
extern const uint16_t * const ff_swb_offset_128 [13];
extern const uint8_t ff_tns_max_bands_1024[13];
extern const uint8_t ff_tns_max_bands_512 [13];
extern const uint8_t ff_tns_max_bands_480 [13];
extern const uint8_t ff_tns_max_bands_128 [13];
#endif /* AVCODEC_AACTAB_H */
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