PeerStreamer

/*

 * bit_allocate.c

 * Copyright (C) 2000-2003 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "a52.h"

#include "a52_internal.h"

static int hthtab[3][50] = {

    {0x730, 0x730, 0x7c0, 0x800, 0x820, 0x840, 0x850, 0x850, 0x860, 0x860,

     0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x890, 0x890,

     0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900,

     0x910, 0x910, 0x910, 0x910, 0x900, 0x8f0, 0x8c0, 0x870, 0x820, 0x7e0,

     0x7a0, 0x770, 0x760, 0x7a0, 0x7c0, 0x7c0, 0x6e0, 0x400, 0x3c0, 0x3c0},

    {0x710, 0x710, 0x7a0, 0x7f0, 0x820, 0x830, 0x840, 0x850, 0x850, 0x860,

     0x860, 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880,

     0x890, 0x890, 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8e0, 0x8f0,

     0x900, 0x910, 0x910, 0x910, 0x910, 0x900, 0x8e0, 0x8b0, 0x870, 0x820,

     0x7e0, 0x7b0, 0x760, 0x770, 0x7a0, 0x7c0, 0x780, 0x5d0, 0x3c0, 0x3c0},

    {0x680, 0x680, 0x750, 0x7b0, 0x7e0, 0x810, 0x820, 0x830, 0x840, 0x850,

     0x850, 0x850, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860,

     0x870, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, 0x890, 0x8a0, 0x8b0,

     0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, 0x910, 0x910, 0x910, 0x900, 0x8f0,

     0x8d0, 0x8b0, 0x840, 0x7f0, 0x790, 0x760, 0x7a0, 0x7c0, 0x7b0, 0x720}

};

static int8_t baptab[305] = {

    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,

    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,        /* 93 padding elems */

    16, 16, 16, 16, 16, 16, 16, 16, 16, 14, 14, 14, 14, 14, 14, 14,

    14, 12, 12, 12, 12, 11, 11, 11, 11, 10, 10, 10, 10,  9,  9,  9,

     9,  8,  8,  8,  8,  7,  7,  7,  7,  6,  6,  6,  6,  5,  5,  5,

     5,  4,  4, -3, -3,  3,  3,  3, -2, -2, -1, -1, -1, -1, -1,  0,

     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,

     0,  0,  0,  0                                        /* 148 padding elems */

};

static int bndtab[30] = {21, 22,  23,  24,  25,  26,  27,  28,  31,  34,

                         37, 40,  43,  46,  49,  55,  61,  67,  73,  79,

                         85, 97, 109, 121, 133, 157, 181, 205, 229, 253};

static int8_t latab[256] = {

    -64, -63, -62, -61, -60, -59, -58, -57, -56, -55, -54, -53,

    -52, -52, -51, -50, -49, -48, -47, -47, -46, -45, -44, -44,

    -43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35,

    -35, -34, -33, -33, -32, -32, -31, -30, -30, -29, -29, -28,

    -28, -27, -27, -26, -26, -25, -25, -24, -24, -23, -23, -22,

    -22, -21, -21, -21, -20, -20, -19, -19, -19, -18, -18, -18,

    -17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14,

    -13, -13, -13, -13, -12, -12, -12, -12, -11, -11, -11, -11,

    -10, -10, -10, -10, -10,  -9,  -9,  -9,  -9,  -9,  -8,  -8,

     -8,  -8,  -8,  -8,  -7,  -7,  -7,  -7,  -7,  -7,  -6,  -6,

     -6,  -6,  -6,  -6,  -6,  -6,  -5,  -5,  -5,  -5,  -5,  -5,

     -5,  -5,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,

     -4,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,

     -3,  -3,  -3,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,

     -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -1,  -1,

     -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,

     -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,

     -1,  -1,  -1,  -1,  -1,  -1,   0,   0,   0,   0,   0,   0,

      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,

      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,

      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,

      0,   0,   0,   0

};

#define UPDATE_LEAK()                 \

do {                                \

    fastleak += fdecay;                \

    if (fastleak > psd + fgain)        \

        fastleak = psd + fgain;        \

    slowleak += sdecay;                \

    if (slowleak > psd + sgain)        \

        slowleak = psd + sgain;        \

} while (0)

#define COMPUTE_MASK()                                \

do {                                                \

    if (psd > dbknee)                                \

        mask -= (psd - dbknee) >> 2;                \

    if (mask > hth [i >> halfrate])                \

        mask = hth [i >> halfrate];                \

    mask -= snroffset + 128 * deltba[i];        \

    mask = (mask > 0) ? 0 : ((-mask) >> 5);        \

    mask -= floor;                                \

} while (0)

void a52_bit_allocate (a52_state_t * state, ba_t * ba, int bndstart,

                       int start, int end, int fastleak, int slowleak,

                       expbap_t * expbap)

{

    static int slowgain[4] = {0x540, 0x4d8, 0x478, 0x410};

    static int dbpbtab[4]  = {0xc00, 0x500, 0x300, 0x100};

    static int floortab[8] = {0x910, 0x950, 0x990, 0x9d0,

                              0xa10, 0xa90, 0xb10, 0x1400};

    int i, j;

    uint8_t * exp;

    int8_t * bap;

    int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;

    int psd, mask;

    int8_t * deltba;

    int * hth;

    int halfrate;

    halfrate = state->halfrate;

    fdecay = (63 + 20 * ((state->bai >> 7) & 3)) >> halfrate;        /* fdcycod */

    fgain = 128 + 128 * (ba->bai & 7);                                /* fgaincod */

    sdecay = (15 + 2 * (state->bai >> 9)) >> halfrate;                /* sdcycod */

    sgain = slowgain[(state->bai >> 5) & 3];                        /* sgaincod */

    dbknee = dbpbtab[(state->bai >> 3) & 3];                        /* dbpbcod */

    hth = hthtab[state->fscod];

    /*

     * if there is no delta bit allocation, make deltba point to an area

     * known to contain zeroes. baptab+156 here.

     */

    deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;

    floor = floortab[state->bai & 7];                                /* floorcod */

    snroffset = 960 - 64 * state->csnroffst - 4 * (ba->bai >> 3) + floor;

    floor >>= 5;

    exp = expbap->exp;

    bap = expbap->bap;

    i = bndstart;

    j = start;

    if (start == 0) {        /* not the coupling channel */

        int lowcomp;

        lowcomp = 0;

        j = end - 1;

        do {

            if (i < j) {

                if (exp[i+1] == exp[i] - 2)

                    lowcomp = 384;

                else if (lowcomp && (exp[i+1] > exp[i]))

                    lowcomp -= 64;

            }

            psd = 128 * exp[i];

            mask = psd + fgain + lowcomp;

            COMPUTE_MASK ();

            bap[i] = (baptab+156)[mask + 4 * exp[i]];

            i++;

        } while ((i < 3) || ((i < 7) && (exp[i] > exp[i-1])));

        fastleak = psd + fgain;

        slowleak = psd + sgain;

        while (i < 7) {

            if (i < j) {

                if (exp[i+1] == exp[i] - 2)

                    lowcomp = 384;

                else if (lowcomp && (exp[i+1] > exp[i]))

                    lowcomp -= 64;

            }

            psd = 128 * exp[i];

            UPDATE_LEAK ();

            mask = ((fastleak + lowcomp < slowleak) ?

                    fastleak + lowcomp : slowleak);

            COMPUTE_MASK ();

            bap[i] = (baptab+156)[mask + 4 * exp[i]];

            i++;

        }

        if (end == 7)        /* lfe channel */

            return;

        do {

            if (exp[i+1] == exp[i] - 2)

                lowcomp = 320;

            else if (lowcomp && (exp[i+1] > exp[i]))

                lowcomp -= 64;

            psd = 128 * exp[i];

            UPDATE_LEAK ();

            mask = ((fastleak + lowcomp < slowleak) ?

                    fastleak + lowcomp : slowleak);

            COMPUTE_MASK ();

            bap[i] = (baptab+156)[mask + 4 * exp[i]];

            i++;

        } while (i < 20);

        while (lowcomp > 128) {                /* two iterations maximum */

            lowcomp -= 128;

            psd = 128 * exp[i];

            UPDATE_LEAK ();

            mask = ((fastleak + lowcomp < slowleak) ?

                    fastleak + lowcomp : slowleak);

            COMPUTE_MASK ();

            bap[i] = (baptab+156)[mask + 4 * exp[i]];

            i++;

        }

        j = i;

    }

    do {

        int startband, endband;

        startband = j;

        endband = (bndtab[i-20] < end) ? bndtab[i-20] : end;

        psd = 128 * exp[j++];

        while (j < endband) {

            int next, delta;

            next = 128 * exp[j++];

            delta = next - psd;

            switch (delta >> 9) {

            case -6: case -5: case -4: case -3: case -2:

                psd = next;

                break;

            case -1:

                psd = next + latab[(-delta) >> 1];

                break;

            case 0:

                psd += latab[delta >> 1];

                break;

            }

        }

        /* minpsd = -289 */

        UPDATE_LEAK ();

        mask = (fastleak < slowleak) ? fastleak : slowleak;

        COMPUTE_MASK ();

        i++;

        j = startband;

        do {

            /* max(mask+4*exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4*exp */

            /* min(mask+4*exp)=-156=-(sgain-deltba-snroffset)>>5 */

            bap[j] = (baptab+156)[mask + 4 * exp[j]];

        } while (++j < endband);

    } while (j < end);

}