1/* 2 * Header file for hardcoded mpegaudiodec tables 3 * 4 * Copyright (c) 2009 Reimar D��ffinger <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 29#define TABLE_4_3_SIZE (8191 + 16)*4 30#if CONFIG_HARDCODED_TABLES 31#define mpegaudio_tableinit() 32#include "libavcodec/mpegaudio_tables.h" 33#else 34static int8_t table_4_3_exp[TABLE_4_3_SIZE]; 35static uint32_t table_4_3_value[TABLE_4_3_SIZE]; 36static uint32_t exp_table_fixed[512]; 37static uint32_t expval_table_fixed[512][16]; 38static float exp_table_float[512]; 39static float expval_table_float[512][16]; 40 41#define FRAC_BITS 23 42#define IMDCT_SCALAR 1.759 43 44static void mpegaudio_tableinit(void) 45{ 46 int i, value, exponent; 47 for (i = 1; i < TABLE_4_3_SIZE; i++) { 48 double value = i / 4; 49 double f, fm; 50 int e, m; 51 /* cbrtf() isn't available on all systems, so we use powf(). */ 52 f = value / IMDCT_SCALAR * pow(value, 1.0 / 3.0) * pow(2, (i & 3) * 0.25); 53 fm = frexp(f, &e); 54 m = (uint32_t)(fm * (1LL << 31) + 0.5); 55 e += FRAC_BITS - 31 + 5 - 100; 56 57 /* normalized to FRAC_BITS */ 58 table_4_3_value[i] = m; 59 table_4_3_exp[i] = -e; 60 } 61 for (exponent = 0; exponent < 512; exponent++) { 62 for (value = 0; value < 16; value++) { 63 /* cbrtf() isn't available on all systems, so we use powf(). */ 64 double f = (double)value * pow(value, 1.0 / 3.0) * pow(2, (exponent - 400) * 0.25 + FRAC_BITS + 5) / IMDCT_SCALAR; 65 /* llrint() isn't always available, so round and cast manually. */ 66 expval_table_fixed[exponent][value] = (long long int) (f < 0xFFFFFFFF ? floor(f + 0.5) : 0xFFFFFFFF); 67 expval_table_float[exponent][value] = f; 68 } 69 exp_table_fixed[exponent] = expval_table_fixed[exponent][1]; 70 exp_table_float[exponent] = expval_table_float[exponent][1]; 71 } 72} 73#endif /* CONFIG_HARDCODED_TABLES */ 74 75#endif /* AVCODEC_MPEGAUDIO_TABLEGEN_H */ 76