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57 lines
2.0 KiB
57 lines
2.0 KiB
22 years ago
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/*
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* Common code between AC3 encoder and decoder
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* Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
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*
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* This library 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 of the License, or (at your option) any later version.
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*
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* This library 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 this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
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#define AC3_MAX_CHANNELS 6 /* including LFE channel */
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#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
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#define AC3_FRAME_SIZE (NB_BLOCKS * 256)
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/* exponent encoding strategy */
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#define EXP_REUSE 0
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#define EXP_NEW 1
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#define EXP_D15 1
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#define EXP_D25 2
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#define EXP_D45 3
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typedef struct AC3BitAllocParameters {
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int fscod; /* frequency */
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int halfratecod;
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int sgain, sdecay, fdecay, dbknee, floor;
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int cplfleak, cplsleak;
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} AC3BitAllocParameters;
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extern const UINT16 ac3_freqs[3];
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extern const UINT16 ac3_bitratetab[19];
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extern const INT16 ac3_window[256];
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extern const UINT8 sdecaytab[4];
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extern const UINT8 fdecaytab[4];
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extern const UINT16 sgaintab[4];
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extern const UINT16 dbkneetab[4];
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extern const UINT16 floortab[8];
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extern const UINT16 fgaintab[8];
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void ac3_common_init(void);
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void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, UINT8 *bap,
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INT8 *exp, int start, int end,
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int snroffset, int fgain, int is_lfe,
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int deltbae,int deltnseg,
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UINT8 *deltoffst, UINT8 *deltlen, UINT8 *deltba);
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