ref: 3254623f0745837118e0d5d739fa6c402fd5b9d3
dir: /libfaad/codebook/hcb.h/
/* ** FAAD - Freeware Advanced Audio Decoder ** Copyright (C) 2002 M. Bakker ** ** This program is free software; you can redistribute it and/or modify ** it under the terms of the GNU General Public License as published by ** the Free Software Foundation; either version 2 of the License, or ** (at your option) any later version. ** ** This program 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 General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program; if not, write to the Free Software ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ** ** $Id: hcb.h,v 1.4 2003/05/18 18:14:37 menno Exp $ **/ #ifndef __HCB_H__ #define __HCB_H__ #ifdef __cplusplus extern "C" { #endif /* * Optimal huffman decoding for AAC taken from: * "SELECTING AN OPTIMAL HUFFMAN DECODER FOR AAC" by * VLADIMIR Z. MESAROVIC , RAGHUNATH RAO, MIROSLAV V. DOKIC, and SACHIN DEO * AES paper 5436 * * 2 methods are used for huffman decoding: * - binary search * - 2-step table lookup * * The choice of the "optimal" method is based on the fact that if the * memory size for the Two-step is exorbitantly high then the decision * is Binary search for that codebook. However, for marginally more memory * size, if Twostep outperforms even the best case of Binary then the * decision is Two-step for that codebook. * * The following methods are used for the different tables. * codebook "optimal" method * HCB_1 2-Step * HCB_2 2-Step * HCB_3 Binary * HCB_4 2-Step * HCB_5 Binary * HCB_6 2-Step * HCB_7 Binary * HCB_8 2-Step * HCB_9 Binary * HCB_10 2-Step * HCB_11 2-Step * HCB_SF Binary * */ #define ZERO_HCB 0 #define FIRST_PAIR_HCB 5 #define ESC_HCB 11 #define QUAD_LEN 4 #define PAIR_LEN 2 #define BOOKSCL 12 #define NOISE_HCB 13 #define INTENSITY_HCB2 14 #define INTENSITY_HCB 15 /* 1st step table */ typedef struct { uint8_t offset; uint8_t extra_bits; } hcb; /* 2nd step table with quadruple data */ typedef struct { uint8_t bits; int8_t x; int8_t y; } hcb_2_pair; typedef struct { uint8_t bits; int8_t x; int8_t y; int8_t v; int8_t w; } hcb_2_quad; /* binary search table */ typedef struct { uint8_t is_leaf; int8_t data[4]; } hcb_bin_quad; typedef struct { uint8_t is_leaf; int8_t data[2]; } hcb_bin_pair; #if 0 extern hcb hcb1_1[]; extern hcb hcb2_1[]; extern hcb hcb4_1[]; extern hcb hcb6_1[]; extern hcb hcb8_1[]; extern hcb hcb10_1[]; extern hcb hcb11_1[]; extern hcb_2_quad hcb1_2[]; extern hcb_2_quad hcb2_2[]; extern hcb_2_quad hcb4_2[]; extern hcb_2_pair hcb6_2[]; extern hcb_2_pair hcb8_2[]; extern hcb_2_pair hcb10_2[]; extern hcb_2_pair hcb11_2[]; extern hcb_bin_quad hcb3[]; extern hcb_bin_pair hcb5[]; extern hcb_bin_pair hcb7[]; extern hcb_bin_pair hcb9[]; extern uint8_t hcb_sf[][2]; #else #include "codebook/hcb_1.h" #include "codebook/hcb_2.h" #include "codebook/hcb_3.h" #include "codebook/hcb_4.h" #include "codebook/hcb_5.h" #include "codebook/hcb_6.h" #include "codebook/hcb_7.h" #include "codebook/hcb_8.h" #include "codebook/hcb_9.h" #include "codebook/hcb_10.h" #include "codebook/hcb_11.h" #include "codebook/hcb_sf.h" #endif #ifdef __cplusplus } #endif #endif