Libav 0.7.1
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00001 /* 00002 * Common code between the AC-3 encoder and decoder 00003 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard 00004 * 00005 * This file is part of Libav. 00006 * 00007 * Libav is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * Libav is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with Libav; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00027 #ifndef AVCODEC_AC3_H 00028 #define AVCODEC_AC3_H 00029 00030 #define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */ 00031 #define AC3_MAX_CHANNELS 7 00032 #define CPL_CH 0 00034 #define AC3_MAX_COEFS 256 00035 #define AC3_BLOCK_SIZE 256 00036 #define AC3_MAX_BLOCKS 6 00037 #define AC3_FRAME_SIZE (AC3_MAX_BLOCKS * 256) 00038 #define AC3_WINDOW_SIZE (AC3_BLOCK_SIZE * 2) 00039 #define AC3_CRITICAL_BANDS 50 00040 #define AC3_MAX_CPL_BANDS 18 00041 00042 #include "ac3tab.h" 00043 00044 /* exponent encoding strategy */ 00045 #define EXP_REUSE 0 00046 #define EXP_NEW 1 00047 00048 #define EXP_D15 1 00049 #define EXP_D25 2 00050 #define EXP_D45 3 00051 00052 /* pre-defined gain values */ 00053 #define LEVEL_PLUS_3DB 1.4142135623730950 00054 #define LEVEL_PLUS_1POINT5DB 1.1892071150027209 00055 #define LEVEL_MINUS_1POINT5DB 0.8408964152537145 00056 #define LEVEL_MINUS_3DB 0.7071067811865476 00057 #define LEVEL_MINUS_4POINT5DB 0.5946035575013605 00058 #define LEVEL_MINUS_6DB 0.5000000000000000 00059 #define LEVEL_MINUS_9DB 0.3535533905932738 00060 #define LEVEL_ZERO 0.0000000000000000 00061 #define LEVEL_ONE 1.0000000000000000 00062 00064 typedef enum { 00065 DBA_REUSE = 0, 00066 DBA_NEW, 00067 DBA_NONE, 00068 DBA_RESERVED 00069 } AC3DeltaStrategy; 00070 00072 typedef enum { 00073 AC3_CHMODE_DUALMONO = 0, 00074 AC3_CHMODE_MONO, 00075 AC3_CHMODE_STEREO, 00076 AC3_CHMODE_3F, 00077 AC3_CHMODE_2F1R, 00078 AC3_CHMODE_3F1R, 00079 AC3_CHMODE_2F2R, 00080 AC3_CHMODE_3F2R 00081 } AC3ChannelMode; 00082 00083 typedef struct AC3BitAllocParameters { 00084 int sr_code; 00085 int sr_shift; 00086 int slow_gain, slow_decay, fast_decay, db_per_bit, floor; 00087 int cpl_fast_leak, cpl_slow_leak; 00088 } AC3BitAllocParameters; 00089 00094 typedef struct { 00098 uint16_t sync_word; 00099 uint16_t crc1; 00100 uint8_t sr_code; 00101 uint8_t bitstream_id; 00102 uint8_t bitstream_mode; 00103 uint8_t channel_mode; 00104 uint8_t lfe_on; 00105 uint8_t frame_type; 00106 int substreamid; 00107 int center_mix_level; 00108 int surround_mix_level; 00109 uint16_t channel_map; 00110 int num_blocks; 00111 00116 uint8_t sr_shift; 00117 uint16_t sample_rate; 00118 uint32_t bit_rate; 00119 uint8_t channels; 00120 uint16_t frame_size; 00121 int64_t channel_layout; 00123 } AC3HeaderInfo; 00124 00125 typedef enum { 00126 EAC3_FRAME_TYPE_INDEPENDENT = 0, 00127 EAC3_FRAME_TYPE_DEPENDENT, 00128 EAC3_FRAME_TYPE_AC3_CONVERT, 00129 EAC3_FRAME_TYPE_RESERVED 00130 } EAC3FrameType; 00131 00132 void ff_ac3_common_init(void); 00133 00148 void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd, 00149 int16_t *band_psd); 00150 00173 int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd, 00174 int start, int end, int fast_gain, int is_lfe, 00175 int dba_mode, int dba_nsegs, uint8_t *dba_offsets, 00176 uint8_t *dba_lengths, uint8_t *dba_values, 00177 int16_t *mask); 00178 00179 #endif /* AVCODEC_AC3_H */