libavcodec/ac3dec_data.c - third_party/ffmpeg - Git at Google

 /*
  * AC-3 and E-AC-3 decoder tables
  * Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@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
  * Tables taken directly from the AC-3 spec or derived from it.
  */

 #include "ac3dec_data.h"
 #include "libavutil/thread.h"

 /**
  * Table used to ungroup 3 values stored in 5 bits.
  * Used by bap=1 mantissas and GAQ.
  * ff_ac3_ungroup_3_in_5_bits_tab[i] = { i/9, (i%9)/3, (i%9)%3 }
  */
 const uint8_t ff_ac3_ungroup_3_in_5_bits_tab[32][3] = {
     { 0, 0, 0 }, { 0, 0, 1 }, { 0, 0, 2 }, { 0, 1, 0 },
     { 0, 1, 1 }, { 0, 1, 2 }, { 0, 2, 0 }, { 0, 2, 1 },
     { 0, 2, 2 }, { 1, 0, 0 }, { 1, 0, 1 }, { 1, 0, 2 },
     { 1, 1, 0 }, { 1, 1, 1 }, { 1, 1, 2 }, { 1, 2, 0 },
     { 1, 2, 1 }, { 1, 2, 2 }, { 2, 0, 0 }, { 2, 0, 1 },
     { 2, 0, 2 }, { 2, 1, 0 }, { 2, 1, 1 }, { 2, 1, 2 },
     { 2, 2, 0 }, { 2, 2, 1 }, { 2, 2, 2 }, { 3, 0, 0 },
     { 3, 0, 1 }, { 3, 0, 2 }, { 3, 1, 0 }, { 3, 1, 1 }
 };

 /**
  * table for ungrouping 3 values in 7 bits.
  * used for exponents and bap=2 mantissas
  */
 uint8_t ff_ac3_ungroup_3_in_7_bits_tab[128][3];

 /**
  * Symmetrical Dequantization
  * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
  *            Tables 7.19 to 7.23
  */
 #define SYMMETRIC_DEQUANT(code, levels) (((code - (levels >> 1)) * (1 << 24)) / levels)
 /**
  * Ungrouped mantissa tables; the extra entry is padding to avoid range checks
  */
 /**
  * Table 7.21
  */
 const int ff_ac3_bap3_mantissas[7 + 1] = {
     SYMMETRIC_DEQUANT(0, 7),
     SYMMETRIC_DEQUANT(1, 7),
     SYMMETRIC_DEQUANT(2, 7),
     SYMMETRIC_DEQUANT(3, 7),
     SYMMETRIC_DEQUANT(4, 7),
     SYMMETRIC_DEQUANT(5, 7),
     SYMMETRIC_DEQUANT(6, 7),
 };
 /**
  * Table 7.23
  */
 const int ff_ac3_bap5_mantissas[15 + 1] = {
     SYMMETRIC_DEQUANT(0,  15),
     SYMMETRIC_DEQUANT(1,  15),
     SYMMETRIC_DEQUANT(2,  15),
     SYMMETRIC_DEQUANT(3,  15),
     SYMMETRIC_DEQUANT(4,  15),
     SYMMETRIC_DEQUANT(5,  15),
     SYMMETRIC_DEQUANT(6,  15),
     SYMMETRIC_DEQUANT(7,  15),
     SYMMETRIC_DEQUANT(8,  15),
     SYMMETRIC_DEQUANT(9,  15),
     SYMMETRIC_DEQUANT(10, 15),
     SYMMETRIC_DEQUANT(11, 15),
     SYMMETRIC_DEQUANT(12, 15),
     SYMMETRIC_DEQUANT(13, 15),
     SYMMETRIC_DEQUANT(14, 15),
 };

 int ff_ac3_bap1_mantissas[32][3];
 int ff_ac3_bap2_mantissas[128][3];
 int ff_ac3_bap4_mantissas[128][2];

 static inline int
 symmetric_dequant(int code, int levels)
 {
     return SYMMETRIC_DEQUANT(code, levels);
 }

 static av_cold void ac3_init_static(void)
 {
     /* generate table for ungrouping 3 values in 7 bits
        reference: Section 7.1.3 Exponent Decoding */
     for (int i = 0; i < 128; ++i) {
         ff_ac3_ungroup_3_in_7_bits_tab[i][0] =  i / 25;
         ff_ac3_ungroup_3_in_7_bits_tab[i][1] = (i % 25) / 5;
         ff_ac3_ungroup_3_in_7_bits_tab[i][2] = (i % 25) % 5;
     }

     /* generate grouped mantissa tables
        reference: Section 7.3.5 Ungrouping of Mantissas */
     for (int i = 0; i < 32; ++i) {
         /* bap=1 mantissas */
         ff_ac3_bap1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3);
         ff_ac3_bap1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3);
         ff_ac3_bap1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 3);
     }
     for (int i = 0; i < 128; ++i) {
         /* bap=2 mantissas */
         ff_ac3_bap2_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_7_bits_tab[i][0], 5);
         ff_ac3_bap2_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_7_bits_tab[i][1], 5);
         ff_ac3_bap2_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_7_bits_tab[i][2], 5);

         /* bap=4 mantissas */
         ff_ac3_bap4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
         ff_ac3_bap4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
     }
 }

 av_cold void ff_ac3_init_static(void)
 {
     static AVOnce ac3_init_static_once = AV_ONCE_INIT;
     ff_thread_once(&ac3_init_static_once, ac3_init_static);
 }

 /**
  * Quantization table: levels for symmetric. bits for asymmetric.
  * reference: Table 7.18 Mapping of bap to Quantizer
  */
 const uint8_t ff_ac3_quantization_tab[16] = {
     0, 3, 5, 7, 11, 15,
     5, 6, 7, 8, 9, 10, 11, 12, 14, 16
 };

 /**
  * Table for default stereo downmixing coefficients
  * reference: Section 7.8.2 Downmixing Into Two Channels
  */
 const uint8_t ff_ac3_default_coeffs[8][5][2] = {
     { { 2, 7 }, { 7, 2 },                               },
     { { 4, 4 },                                         },
     { { 2, 7 }, { 7, 2 },                               },
     { { 2, 7 }, { 5, 5 }, { 7, 2 },                     },
     { { 2, 7 }, { 7, 2 }, { 6, 6 },                     },
     { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 8, 8 },           },
     { { 2, 7 }, { 7, 2 }, { 6, 7 }, { 7, 6 },           },
     { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
 };

 const uint8_t ff_eac3_hebap_tab[64] = {
     0, 1, 2, 3, 4, 5, 6, 7, 8, 8,
     8, 8, 9, 9, 9, 10, 10, 10, 10, 11,
     11, 11, 11, 12, 12, 12, 12, 13, 13, 13,
     13, 14, 14, 14, 14, 15, 15, 15, 15, 16,
     16, 16, 16, 17, 17, 17, 17, 18, 18, 18,
     18, 18, 18, 18, 18, 19, 19, 19, 19, 19,
     19, 19, 19, 19,
 };

 /**
  * Table E2.15 Default Spectral Extension Banding Structure
  */
 const uint8_t ff_eac3_default_spx_band_struct[17] =
 { 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 };

 /** Adjustments in dB gain (LFE, +10 to -21 dB) */
 const float ff_eac3_gain_levels_lfe[32] = {
     3.162275, 2.818382, 2.511886, 2.238719, 1.995261, 1.778278, 1.584893,
     1.412536, 1.258924, 1.122018, 1.000000, 0.891251, 0.794328, 0.707946,
     0.630957, 0.562341, 0.501187, 0.446683, 0.398107, 0.354813, 0.316227,
     0.281838, 0.251188, 0.223872, 0.199526, 0.177828, 0.158489, 0.141253,
     0.125892, 0.112201, 0.100000, 0.089125
 };
	/*
	* AC-3 and E-AC-3 decoder tables
	* Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@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
	* Tables taken directly from the AC-3 spec or derived from it.
	*/

	#include "ac3dec_data.h"
	#include "libavutil/thread.h"

	/**
	* Table used to ungroup 3 values stored in 5 bits.
	* Used by bap=1 mantissas and GAQ.
	* ff_ac3_ungroup_3_in_5_bits_tab[i] = { i/9, (i%9)/3, (i%9)%3 }
	*/
	const uint8_t ff_ac3_ungroup_3_in_5_bits_tab[32][3] = {
	{ 0, 0, 0 }, { 0, 0, 1 }, { 0, 0, 2 }, { 0, 1, 0 },
	{ 0, 1, 1 }, { 0, 1, 2 }, { 0, 2, 0 }, { 0, 2, 1 },
	{ 0, 2, 2 }, { 1, 0, 0 }, { 1, 0, 1 }, { 1, 0, 2 },
	{ 1, 1, 0 }, { 1, 1, 1 }, { 1, 1, 2 }, { 1, 2, 0 },
	{ 1, 2, 1 }, { 1, 2, 2 }, { 2, 0, 0 }, { 2, 0, 1 },
	{ 2, 0, 2 }, { 2, 1, 0 }, { 2, 1, 1 }, { 2, 1, 2 },
	{ 2, 2, 0 }, { 2, 2, 1 }, { 2, 2, 2 }, { 3, 0, 0 },
	{ 3, 0, 1 }, { 3, 0, 2 }, { 3, 1, 0 }, { 3, 1, 1 }
	};

	/**
	* table for ungrouping 3 values in 7 bits.
	* used for exponents and bap=2 mantissas
	*/
	uint8_t ff_ac3_ungroup_3_in_7_bits_tab[128][3];

	/**
	* Symmetrical Dequantization
	* reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
	* Tables 7.19 to 7.23
	*/
	#define SYMMETRIC_DEQUANT(code, levels) (((code - (levels >> 1)) * (1 << 24)) / levels)
	/**
	* Ungrouped mantissa tables; the extra entry is padding to avoid range checks
	*/
	/**
	* Table 7.21
	*/
	const int ff_ac3_bap3_mantissas[7 + 1] = {
	SYMMETRIC_DEQUANT(0, 7),
	SYMMETRIC_DEQUANT(1, 7),
	SYMMETRIC_DEQUANT(2, 7),
	SYMMETRIC_DEQUANT(3, 7),
	SYMMETRIC_DEQUANT(4, 7),
	SYMMETRIC_DEQUANT(5, 7),
	SYMMETRIC_DEQUANT(6, 7),
	};
	/**
	* Table 7.23
	*/
	const int ff_ac3_bap5_mantissas[15 + 1] = {
	SYMMETRIC_DEQUANT(0, 15),
	SYMMETRIC_DEQUANT(1, 15),
	SYMMETRIC_DEQUANT(2, 15),
	SYMMETRIC_DEQUANT(3, 15),
	SYMMETRIC_DEQUANT(4, 15),
	SYMMETRIC_DEQUANT(5, 15),
	SYMMETRIC_DEQUANT(6, 15),
	SYMMETRIC_DEQUANT(7, 15),
	SYMMETRIC_DEQUANT(8, 15),
	SYMMETRIC_DEQUANT(9, 15),
	SYMMETRIC_DEQUANT(10, 15),
	SYMMETRIC_DEQUANT(11, 15),
	SYMMETRIC_DEQUANT(12, 15),
	SYMMETRIC_DEQUANT(13, 15),
	SYMMETRIC_DEQUANT(14, 15),
	};

	int ff_ac3_bap1_mantissas[32][3];
	int ff_ac3_bap2_mantissas[128][3];
	int ff_ac3_bap4_mantissas[128][2];

	static inline int
	symmetric_dequant(int code, int levels)
	{
	return SYMMETRIC_DEQUANT(code, levels);
	}

	static av_cold void ac3_init_static(void)
	{
	/* generate table for ungrouping 3 values in 7 bits
	reference: Section 7.1.3 Exponent Decoding */
	for (int i = 0; i < 128; ++i) {
	ff_ac3_ungroup_3_in_7_bits_tab[i][0] = i / 25;
	ff_ac3_ungroup_3_in_7_bits_tab[i][1] = (i % 25) / 5;
	ff_ac3_ungroup_3_in_7_bits_tab[i][2] = (i % 25) % 5;
	}

	/* generate grouped mantissa tables
	reference: Section 7.3.5 Ungrouping of Mantissas */
	for (int i = 0; i < 32; ++i) {
	/* bap=1 mantissas */
	ff_ac3_bap1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3);
	ff_ac3_bap1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3);
	ff_ac3_bap1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 3);
	}
	for (int i = 0; i < 128; ++i) {
	/* bap=2 mantissas */
	ff_ac3_bap2_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_7_bits_tab[i][0], 5);
	ff_ac3_bap2_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_7_bits_tab[i][1], 5);
	ff_ac3_bap2_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_7_bits_tab[i][2], 5);

	/* bap=4 mantissas */
	ff_ac3_bap4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
	ff_ac3_bap4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
	}
	}

	av_cold void ff_ac3_init_static(void)
	{
	static AVOnce ac3_init_static_once = AV_ONCE_INIT;
	ff_thread_once(&ac3_init_static_once, ac3_init_static);
	}

	/**
	* Quantization table: levels for symmetric. bits for asymmetric.
	* reference: Table 7.18 Mapping of bap to Quantizer
	*/
	const uint8_t ff_ac3_quantization_tab[16] = {
	0, 3, 5, 7, 11, 15,
	5, 6, 7, 8, 9, 10, 11, 12, 14, 16
	};

	/**
	* Table for default stereo downmixing coefficients
	* reference: Section 7.8.2 Downmixing Into Two Channels
	*/
	const uint8_t ff_ac3_default_coeffs[8][5][2] = {
	{ { 2, 7 }, { 7, 2 }, },
	{ { 4, 4 }, },
	{ { 2, 7 }, { 7, 2 }, },
	{ { 2, 7 }, { 5, 5 }, { 7, 2 }, },
	{ { 2, 7 }, { 7, 2 }, { 6, 6 }, },
	{ { 2, 7 }, { 5, 5 }, { 7, 2 }, { 8, 8 }, },
	{ { 2, 7 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
	{ { 2, 7 }, { 5, 5 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
	};

	const uint8_t ff_eac3_hebap_tab[64] = {
	0, 1, 2, 3, 4, 5, 6, 7, 8, 8,
	8, 8, 9, 9, 9, 10, 10, 10, 10, 11,
	11, 11, 11, 12, 12, 12, 12, 13, 13, 13,
	13, 14, 14, 14, 14, 15, 15, 15, 15, 16,
	16, 16, 16, 17, 17, 17, 17, 18, 18, 18,
	18, 18, 18, 18, 18, 19, 19, 19, 19, 19,
	19, 19, 19, 19,
	};

	/**
	* Table E2.15 Default Spectral Extension Banding Structure
	*/
	const uint8_t ff_eac3_default_spx_band_struct[17] =
	{ 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 };

	/** Adjustments in dB gain (LFE, +10 to -21 dB) */
	const float ff_eac3_gain_levels_lfe[32] = {
	3.162275, 2.818382, 2.511886, 2.238719, 1.995261, 1.778278, 1.584893,
	1.412536, 1.258924, 1.122018, 1.000000, 0.891251, 0.794328, 0.707946,
	0.630957, 0.562341, 0.501187, 0.446683, 0.398107, 0.354813, 0.316227,
	0.281838, 0.251188, 0.223872, 0.199526, 0.177828, 0.158489, 0.141253,
	0.125892, 0.112201, 0.100000, 0.089125
	};