| 1 | /*
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| 2 | * Common code between AC3 encoder and decoder
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| 3 | * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
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| 4 | *
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| 5 | * This library is free software; you can redistribute it and/or
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| 6 | * modify it under the terms of the GNU Lesser General Public
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| 7 | * License as published by the Free Software Foundation; either
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| 8 | * version 2 of the License, or (at your option) any later version.
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| 9 | *
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| 10 | * This library is distributed in the hope that it will be useful,
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 13 | * Lesser General Public License for more details.
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| 14 | *
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| 15 | * You should have received a copy of the GNU Lesser General Public
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| 16 | * License along with this library; if not, write to the Free Software
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| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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| 18 | */
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| 19 |
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| 20 | /**
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| 21 | * @file ac3.h
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| 22 | * Common code between AC3 encoder and decoder.
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| 23 | */
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| 24 |
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| 25 | #define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
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| 26 | #define AC3_MAX_CHANNELS 6 /* including LFE channel */
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| 27 |
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| 28 | #define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
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| 29 | #define AC3_FRAME_SIZE (NB_BLOCKS * 256)
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| 30 |
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| 31 | /* exponent encoding strategy */
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| 32 | #define EXP_REUSE 0
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| 33 | #define EXP_NEW 1
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| 34 |
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| 35 | #define EXP_D15 1
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| 36 | #define EXP_D25 2
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| 37 | #define EXP_D45 3
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| 38 |
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| 39 | typedef struct AC3BitAllocParameters {
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| 40 | int fscod; /* frequency */
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| 41 | int halfratecod;
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| 42 | int sgain, sdecay, fdecay, dbknee, floor;
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| 43 | int cplfleak, cplsleak;
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| 44 | } AC3BitAllocParameters;
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| 45 |
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| 46 | #if 0
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| 47 | extern const uint16_t ac3_freqs[3];
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| 48 | extern const uint16_t ac3_bitratetab[19];
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| 49 | extern const int16_t ac3_window[256];
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| 50 | extern const uint8_t sdecaytab[4];
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| 51 | extern const uint8_t fdecaytab[4];
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| 52 | extern const uint16_t sgaintab[4];
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| 53 | extern const uint16_t dbkneetab[4];
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| 54 | extern const uint16_t floortab[8];
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| 55 | extern const uint16_t fgaintab[8];
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| 56 | #endif
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| 57 |
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| 58 | void ac3_common_init(void);
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| 59 | void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, uint8_t *bap,
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| 60 | int8_t *exp, int start, int end,
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| 61 | int snroffset, int fgain, int is_lfe,
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| 62 | int deltbae,int deltnseg,
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| 63 | uint8_t *deltoffst, uint8_t *deltlen, uint8_t *deltba);
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