PeerStreamer

/*

 * Common code between AC3 encoder and decoder

 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

/**

 * @file ac3.h

 * Common code between AC3 encoder and decoder.

 */

#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */

#define AC3_MAX_CHANNELS 6 /* including LFE channel */

#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */

#define AC3_FRAME_SIZE (NB_BLOCKS * 256)

/* exponent encoding strategy */

#define EXP_REUSE 0

#define EXP_NEW   1

#define EXP_D15   1

#define EXP_D25   2

#define EXP_D45   3

typedef struct AC3BitAllocParameters {

    int fscod; /* frequency */

    int halfratecod;

    int sgain, sdecay, fdecay, dbknee, floor;

    int cplfleak, cplsleak;

} AC3BitAllocParameters;

extern const uint16_t ac3_freqs[3];

extern const uint16_t ac3_bitratetab[19];

extern const int16_t ac3_window[256];

extern const uint8_t sdecaytab[4];

extern const uint8_t fdecaytab[4];

extern const uint16_t sgaintab[4];

extern const uint16_t dbkneetab[4];

extern const uint16_t floortab[8];

extern const uint16_t fgaintab[8];

void ac3_common_init(void);

void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, uint8_t *bap,

                                   int8_t *exp, int start, int end,

                                   int snroffset, int fgain, int is_lfe,

                                   int deltbae,int deltnseg, 

                                   uint8_t *deltoffst, uint8_t *deltlen, uint8_t *deltba);