---

a52_internal.h

/*
 * a52_internal.h
 * Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>
 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
 *
 * This file is part of a52dec, a free ATSC A-52 stream decoder.
 * See http://liba52.sourceforge.net/ for updates.
 *
 * a52dec is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * a52dec 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

typedef struct {
    uint8_t bai;                /* fine SNR offset, fast gain */
    uint8_t deltbae;            /* delta bit allocation exists */
    int8_t deltba[50];          /* per-band delta bit allocation */
} ba_t;

typedef struct {
    uint8_t exp[256];           /* decoded channel exponents */
    int8_t bap[256];            /* derived channel bit allocation */
} expbap_t;

struct a52_state_s {
    uint8_t fscod;              /* sample rate */
    uint8_t halfrate;           /* halfrate factor */
    uint8_t acmod;              /* coded channels */
    uint8_t lfeon;              /* coded lfe channel */
    sample_t clev;              /* centre channel mix level */
    sample_t slev;              /* surround channels mix level */

    int output;                 /* type of output */
    sample_t level;             /* output level */
    sample_t bias;              /* output bias */

    int dynrnge;                /* apply dynamic range */
    sample_t dynrng;            /* dynamic range */
    void * dynrngdata;          /* dynamic range callback funtion and data */
    sample_t (* dynrngcall) (sample_t range, void * dynrngdata);

    uint8_t chincpl;            /* channel coupled */
    uint8_t phsflginu;          /* phase flags in use (stereo only) */
    uint8_t cplstrtmant;        /* coupling channel start mantissa */
    uint8_t cplendmant;         /* coupling channel end mantissa */
    uint32_t cplbndstrc;        /* coupling band structure */
    sample_t cplco[5][18];      /* coupling coordinates */

    /* derived information */
    uint8_t cplstrtbnd;         /* coupling start band (for bit allocation) */
    uint8_t ncplbnd;            /* number of coupling bands */

    uint8_t rematflg;           /* stereo rematrixing */

    uint8_t endmant[5];         /* channel end mantissa */

    uint16_t bai;               /* bit allocation information */

    uint8_t csnroffst;          /* coarse SNR offset */
    ba_t cplba;                 /* coupling bit allocation parameters */
    ba_t ba[5];                 /* channel bit allocation parameters */
    ba_t lfeba;                 /* lfe bit allocation parameters */

    uint8_t cplfleak;           /* coupling fast leak init */
    uint8_t cplsleak;           /* coupling slow leak init */

    expbap_t cpl_expbap;
    expbap_t fbw_expbap[5];
    expbap_t lfe_expbap;

    sample_t * samples;
    int downmixed;
};

#define LEVEL_PLUS6DB 2.0
#define LEVEL_PLUS3DB 1.4142135623730951
#define LEVEL_3DB 0.7071067811865476
#define LEVEL_45DB 0.5946035575013605
#define LEVEL_6DB 0.5

#define EXP_REUSE (0)
#define EXP_D15   (1)
#define EXP_D25   (2)
#define EXP_D45   (3)

#define DELTA_BIT_REUSE (0)
#define DELTA_BIT_NEW (1)
#define DELTA_BIT_NONE (2)
#define DELTA_BIT_RESERVED (3)

void a52_bit_allocate (a52_state_t * state, ba_t * ba, int bndstart,
                       int start, int end, int fastleak, int slowleak,
                       expbap_t * expbap);

int a52_downmix_init (int input, int flags, sample_t * level,
                      sample_t clev, sample_t slev);
int a52_downmix_coeff (sample_t * coeff, int acmod, int output, sample_t level,
                       sample_t clev, sample_t slev);
void a52_downmix (sample_t * samples, int acmod, int output, sample_t bias,
                  sample_t clev, sample_t slev);
void a52_upmix (sample_t * samples, int acmod, int output);

void a52_imdct_init (uint32_t mm_accel);
void a52_imdct_256 (sample_t * data, sample_t * delay, sample_t bias);
void a52_imdct_512 (sample_t * data, sample_t * delay, sample_t bias);

---