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Channel coupling is an optional AC-3 feature that increases quality by combining high frequency information from multiple channels into a single channel. The per-channel high frequency information is sent with less accuracy in both the frequency and time domains. This allows more bits to be used for lower frequencies while preserving enough information to reconstruct the high frequencies.
73 lines
2.6 KiB
C
73 lines
2.6 KiB
C
/*
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* AC-3 tables
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* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_AC3TAB_H
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#define AVCODEC_AC3TAB_H
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#include "libavutil/common.h"
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#include "ac3.h"
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#if CONFIG_HARDCODED_TABLES
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# define HCONST const
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#else
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# define HCONST
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#endif
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extern const uint16_t ff_ac3_frame_size_tab[38][3];
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extern const uint8_t ff_ac3_channels_tab[8];
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extern const uint16_t ff_ac3_channel_layout_tab[8];
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extern const uint8_t ff_ac3_enc_channel_map[8][2][6];
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extern const uint8_t ff_ac3_dec_channel_map[8][2][6];
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extern const uint16_t ff_ac3_sample_rate_tab[3];
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extern const uint16_t ff_ac3_bitrate_tab[19];
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extern const uint8_t ff_ac3_rematrix_band_tab[5];
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extern const uint8_t ff_eac3_default_cpl_band_struct[18];
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extern const int16_t ff_ac3_window[AC3_WINDOW_SIZE/2];
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extern const uint8_t ff_ac3_log_add_tab[260];
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extern const uint16_t ff_ac3_hearing_threshold_tab[AC3_CRITICAL_BANDS][3];
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extern const uint8_t ff_ac3_bap_tab[64];
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extern const uint8_t ff_ac3_slow_decay_tab[4];
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extern const uint8_t ff_ac3_fast_decay_tab[4];
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extern const uint16_t ff_ac3_slow_gain_tab[4];
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extern const uint16_t ff_ac3_db_per_bit_tab[4];
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extern const int16_t ff_ac3_floor_tab[8];
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extern const uint16_t ff_ac3_fast_gain_tab[8];
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extern const uint16_t ff_eac3_default_chmap[8];
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extern const uint8_t ff_ac3_band_start_tab[AC3_CRITICAL_BANDS+1];
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extern HCONST uint8_t ff_ac3_bin_to_band_tab[253];
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/** Custom channel map locations bitmask
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* Other channels described in documentation:
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* Lc/Rc pair, Lrs/Rrs pair, Ts, Lsd/Rsd pair,
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* Lw/Rw pair, Lvh/Rvh pair, Cvh, Reserved, LFE2
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*/
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enum CustomChannelMapLocation{
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AC3_CHMAP_L= 1<<(15-0),
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AC3_CHMAP_C= 1<<(15-1),
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AC3_CHMAP_R= 1<<(15-2),
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AC3_CHMAP_L_SUR= 1<<(15-3),
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AC3_CHMAP_R_SUR = 1<<(15-4),
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AC3_CHMAP_C_SUR= 1<<(15-7),
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AC3_CHMAP_LFE = 1<<(15-15)
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};
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#endif /* AVCODEC_AC3TAB_H */
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