LCOV - code coverage report
Current view: top level - libavcodec - mpegaudio_tablegen.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 26 26 100.0 %
Date: 2017-12-17 16:07:53 Functions: 1 1 100.0 %

          Line data    Source code
       1             : /*
       2             :  * Header file for hardcoded mpegaudiodec tables
       3             :  *
       4             :  * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
       5             :  *
       6             :  * This file is part of FFmpeg.
       7             :  *
       8             :  * FFmpeg is free software; you can redistribute it and/or
       9             :  * modify it under the terms of the GNU Lesser General Public
      10             :  * License as published by the Free Software Foundation; either
      11             :  * version 2.1 of the License, or (at your option) any later version.
      12             :  *
      13             :  * FFmpeg is distributed in the hope that it will be useful,
      14             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      15             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      16             :  * Lesser General Public License for more details.
      17             :  *
      18             :  * You should have received a copy of the GNU Lesser General Public
      19             :  * License along with FFmpeg; if not, write to the Free Software
      20             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      21             :  */
      22             : 
      23             : #ifndef AVCODEC_MPEGAUDIO_TABLEGEN_H
      24             : #define AVCODEC_MPEGAUDIO_TABLEGEN_H
      25             : 
      26             : #include <stdint.h>
      27             : #include <math.h>
      28             : #include "libavutil/attributes.h"
      29             : 
      30             : #define TABLE_4_3_SIZE (8191 + 16)*4
      31             : #if CONFIG_HARDCODED_TABLES
      32             : #define mpegaudio_tableinit()
      33             : #include "libavcodec/mpegaudio_tables.h"
      34             : #else
      35             : static int8_t   table_4_3_exp[TABLE_4_3_SIZE];
      36             : static uint32_t table_4_3_value[TABLE_4_3_SIZE];
      37             : static uint32_t exp_table_fixed[512];
      38             : static uint32_t expval_table_fixed[512][16];
      39             : static float exp_table_float[512];
      40             : static float expval_table_float[512][16];
      41             : 
      42             : #define FRAC_BITS 23
      43             : #define IMDCT_SCALAR 1.759
      44             : 
      45          65 : static av_cold void mpegaudio_tableinit(void)
      46             : {
      47             :     int i, value, exponent;
      48             :     static const double exp2_lut[4] = {
      49             :         1.00000000000000000000, /* 2 ^ (0 * 0.25) */
      50             :         1.18920711500272106672, /* 2 ^ (1 * 0.25) */
      51             :         M_SQRT2               , /* 2 ^ (2 * 0.25) */
      52             :         1.68179283050742908606, /* 2 ^ (3 * 0.25) */
      53             :     };
      54             :     static double pow43_lut[16];
      55          65 :     double exp2_base = 2.11758236813575084767080625169910490512847900390625e-22; // 2^(-72)
      56             :     double exp2_val;
      57          65 :     double pow43_val = 0;
      58        1105 :     for (i = 0; i < 16; ++i)
      59        1040 :         pow43_lut[i] = i * cbrt(i);
      60             : 
      61     2133820 :     for (i = 1; i < TABLE_4_3_SIZE; i++) {
      62             :         double f, fm;
      63             :         int e, m;
      64     2133755 :         double value = i / 4;
      65     2133755 :         if ((i & 3) == 0)
      66      533390 :             pow43_val = value / IMDCT_SCALAR * cbrt(value);
      67     2133755 :         f  = pow43_val * exp2_lut[i & 3];
      68     2133755 :         fm = frexp(f, &e);
      69     2133755 :         m  = llrint(fm * (1LL << 31));
      70     2133755 :         e += FRAC_BITS - 31 + 5 - 100;
      71             : 
      72             :         /* normalized to FRAC_BITS */
      73     2133755 :         table_4_3_value[i] =  m;
      74     2133755 :         table_4_3_exp[i]   = -e;
      75             :     }
      76       33345 :     for (exponent = 0; exponent < 512; exponent++) {
      77       33280 :         if (exponent && (exponent & 3) == 0)
      78        8255 :             exp2_base *= 2;
      79       33280 :         exp2_val = exp2_base * exp2_lut[exponent & 3] / IMDCT_SCALAR;
      80      565760 :         for (value = 0; value < 16; value++) {
      81      532480 :             double f = pow43_lut[value] * exp2_val;
      82      532480 :             expval_table_fixed[exponent][value] = (f < 0xFFFFFFFF ? llrint(f) : 0xFFFFFFFF);
      83      532480 :             expval_table_float[exponent][value] = f;
      84             :         }
      85       33280 :         exp_table_fixed[exponent] = expval_table_fixed[exponent][1];
      86       33280 :         exp_table_float[exponent] = expval_table_float[exponent][1];
      87             :     }
      88          65 : }
      89             : #endif /* CONFIG_HARDCODED_TABLES */
      90             : 
      91             : #endif /* AVCODEC_MPEGAUDIO_TABLEGEN_H */

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