3rdparty/liba52/bit_allocate.c

/*
 * bit_allocate.c
 * 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
 */

#include "config.h"

#include "inttypes.h"

#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-20)[i] < end) ? (bndtab-20)[i] : 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);
}
1	/*
2	* bit_allocate.c
3	* Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>
4	* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
5	*
6	* This file is part of a52dec, a free ATSC A-52 stream decoder.
7	* See http://liba52.sourceforge.net/ for updates.
8	*
9	* a52dec is free software; you can redistribute it and/or modify
10	* it under the terms of the GNU General Public License as published by
11	* the Free Software Foundation; either version 2 of the License, or
12	* (at your option) any later version.
13	*
14	* a52dec is distributed in the hope that it will be useful,
15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17	* GNU General Public License for more details.
18	*
19	* You should have received a copy of the GNU General Public License
20	* along with this program; if not, write to the Free Software
21	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22	*/
23
24	#include "config.h"
25
26	#include "inttypes.h"
27
28	#include "a52.h"
29	#include "a52_internal.h"
30
31	static int hthtab[3][50] = {
32	{0x730, 0x730, 0x7c0, 0x800, 0x820, 0x840, 0x850, 0x850, 0x860, 0x860,
33	0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x890, 0x890,
34	0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900,
35	0x910, 0x910, 0x910, 0x910, 0x900, 0x8f0, 0x8c0, 0x870, 0x820, 0x7e0,
36	0x7a0, 0x770, 0x760, 0x7a0, 0x7c0, 0x7c0, 0x6e0, 0x400, 0x3c0, 0x3c0},
37	{0x710, 0x710, 0x7a0, 0x7f0, 0x820, 0x830, 0x840, 0x850, 0x850, 0x860,
38	0x860, 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880,
39	0x890, 0x890, 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8e0, 0x8f0,
40	0x900, 0x910, 0x910, 0x910, 0x910, 0x900, 0x8e0, 0x8b0, 0x870, 0x820,
41	0x7e0, 0x7b0, 0x760, 0x770, 0x7a0, 0x7c0, 0x780, 0x5d0, 0x3c0, 0x3c0},
42	{0x680, 0x680, 0x750, 0x7b0, 0x7e0, 0x810, 0x820, 0x830, 0x840, 0x850,
43	0x850, 0x850, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860,
44	0x870, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, 0x890, 0x8a0, 0x8b0,
45	0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, 0x910, 0x910, 0x910, 0x900, 0x8f0,
46	0x8d0, 0x8b0, 0x840, 0x7f0, 0x790, 0x760, 0x7a0, 0x7c0, 0x7b0, 0x720}
47	};
48
49	static int8_t baptab[305] = {
50	16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
51	16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
52	16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
53	16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
54	16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
55	16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, /* 93 padding elems */
56
57	16, 16, 16, 16, 16, 16, 16, 16, 16, 14, 14, 14, 14, 14, 14, 14,
58	14, 12, 12, 12, 12, 11, 11, 11, 11, 10, 10, 10, 10, 9, 9, 9,
59	9, 8, 8, 8, 8, 7, 7, 7, 7, 6, 6, 6, 6, 5, 5, 5,
60	5, 4, 4, -3, -3, 3, 3, 3, -2, -2, -1, -1, -1, -1, -1, 0,
61
62	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
63	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
64	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
65	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
66	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
67	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
68	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
69	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
70	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
71	0, 0, 0, 0 /* 148 padding elems */
72	};
73
74	static int bndtab[30] = {21, 22, 23, 24, 25, 26, 27, 28, 31, 34,
75	37, 40, 43, 46, 49, 55, 61, 67, 73, 79,
76	85, 97, 109, 121, 133, 157, 181, 205, 229, 253};
77
78	static int8_t latab[256] = {
79	-64, -63, -62, -61, -60, -59, -58, -57, -56, -55, -54, -53,
80	-52, -52, -51, -50, -49, -48, -47, -47, -46, -45, -44, -44,
81	-43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35,
82	-35, -34, -33, -33, -32, -32, -31, -30, -30, -29, -29, -28,
83	-28, -27, -27, -26, -26, -25, -25, -24, -24, -23, -23, -22,
84	-22, -21, -21, -21, -20, -20, -19, -19, -19, -18, -18, -18,
85	-17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14,
86	-13, -13, -13, -13, -12, -12, -12, -12, -11, -11, -11, -11,
87	-10, -10, -10, -10, -10, -9, -9, -9, -9, -9, -8, -8,
88	-8, -8, -8, -8, -7, -7, -7, -7, -7, -7, -6, -6,
89	-6, -6, -6, -6, -6, -6, -5, -5, -5, -5, -5, -5,
90	-5, -5, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4,
91	-4, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,
92	-3, -3, -3, -2, -2, -2, -2, -2, -2, -2, -2, -2,
93	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1,
94	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
95	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
96	-1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0,
97	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
98	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
99	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
100	0, 0, 0, 0
101	};
102
103	#define UPDATE_LEAK() \
104	do { \
105	fastleak += fdecay; \
106	if (fastleak > psd + fgain) \
107	fastleak = psd + fgain; \
108	slowleak += sdecay; \
109	if (slowleak > psd + sgain) \
110	slowleak = psd + sgain; \
111	} while (0)
112
113	#define COMPUTE_MASK() \
114	do { \
115	if (psd > dbknee) \
116	mask -= (psd - dbknee) >> 2; \
117	if (mask > hth [i >> halfrate]) \
118	mask = hth [i >> halfrate]; \
119	mask -= snroffset + 128 * deltba[i]; \
120	mask = (mask > 0) ? 0 : ((-mask) >> 5); \
121	mask -= floor; \
122	} while (0)
123
124	void a52_bit_allocate (a52_state_t * state, ba_t * ba, int bndstart,
125	int start, int end, int fastleak, int slowleak,
126	expbap_t * expbap)
127	{
128	static int slowgain[4] = {0x540, 0x4d8, 0x478, 0x410};
129	static int dbpbtab[4] = {0xc00, 0x500, 0x300, 0x100};
130	static int floortab[8] = {0x910, 0x950, 0x990, 0x9d0,
131	0xa10, 0xa90, 0xb10, 0x1400};
132
133	int i, j;
134	uint8_t * exp;
135	int8_t * bap;
136	int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;
137	int psd, mask;
138	int8_t * deltba;
139	int * hth;
140	int halfrate;
141
142	halfrate = state->halfrate;
143	fdecay = (63 + 20 * ((state->bai >> 7) & 3)) >> halfrate; /* fdcycod */
144	fgain = 128 + 128 * (ba->bai & 7); /* fgaincod */
145	sdecay = (15 + 2 * (state->bai >> 9)) >> halfrate; /* sdcycod */
146	sgain = slowgain[(state->bai >> 5) & 3]; /* sgaincod */
147	dbknee = dbpbtab[(state->bai >> 3) & 3]; /* dbpbcod */
148	hth = hthtab[state->fscod];
149	/*
150	* if there is no delta bit allocation, make deltba point to an area
151	* known to contain zeroes. baptab+156 here.
152	*/
153	deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;
154	floor = floortab[state->bai & 7]; /* floorcod */
155	snroffset = 960 - 64 * state->csnroffst - 4 * (ba->bai >> 3) + floor;
156	floor >>= 5;
157
158	exp = expbap->exp;
159	bap = expbap->bap;
160
161	i = bndstart;
162	j = start;
163	if (start == 0) { /* not the coupling channel */
164	int lowcomp;
165
166	lowcomp = 0;
167	j = end - 1;
168	do {
169	if (i < j) {
170	if (exp[i+1] == exp[i] - 2)
171	lowcomp = 384;
172	else if (lowcomp && (exp[i+1] > exp[i]))
173	lowcomp -= 64;
174	}
175	psd = 128 * exp[i];
176	mask = psd + fgain + lowcomp;
177	COMPUTE_MASK ();
178	bap[i] = (baptab+156)[mask + 4 * exp[i]];
179	i++;
180	} while ((i < 3) \|\| ((i < 7) && (exp[i] > exp[i-1])));
181	fastleak = psd + fgain;
182	slowleak = psd + sgain;
183
184	while (i < 7) {
185	if (i < j) {
186	if (exp[i+1] == exp[i] - 2)
187	lowcomp = 384;
188	else if (lowcomp && (exp[i+1] > exp[i]))
189	lowcomp -= 64;
190	}
191	psd = 128 * exp[i];
192	UPDATE_LEAK ();
193	mask = ((fastleak + lowcomp < slowleak) ?
194	fastleak + lowcomp : slowleak);
195	COMPUTE_MASK ();
196	bap[i] = (baptab+156)[mask + 4 * exp[i]];
197	i++;
198	}
199
200	if (end == 7) /* lfe channel */
201	return;
202
203	do {
204	if (exp[i+1] == exp[i] - 2)
205	lowcomp = 320;
206	else if (lowcomp && (exp[i+1] > exp[i]))
207	lowcomp -= 64;
208	psd = 128 * exp[i];
209	UPDATE_LEAK ();
210	mask = ((fastleak + lowcomp < slowleak) ?
211	fastleak + lowcomp : slowleak);
212	COMPUTE_MASK ();
213	bap[i] = (baptab+156)[mask + 4 * exp[i]];
214	i++;
215	} while (i < 20);
216
217	while (lowcomp > 128) { /* two iterations maximum */
218	lowcomp -= 128;
219	psd = 128 * exp[i];
220	UPDATE_LEAK ();
221	mask = ((fastleak + lowcomp < slowleak) ?
222	fastleak + lowcomp : slowleak);
223	COMPUTE_MASK ();
224	bap[i] = (baptab+156)[mask + 4 * exp[i]];
225	i++;
226	}
227	j = i;
228	}
229
230	do {
231	int startband, endband;
232
233	startband = j;
234	endband = ((bndtab-20)[i] < end) ? (bndtab-20)[i] : end;
235	psd = 128 * exp[j++];
236	while (j < endband) {
237	int next, delta;
238
239	next = 128 * exp[j++];
240	delta = next - psd;
241	switch (delta >> 9) {
242	case -6: case -5: case -4: case -3: case -2:
243	psd = next;
244	break;
245	case -1:
246	psd = next + latab[(-delta) >> 1];
247	break;
248	case 0:
249	psd += latab[delta >> 1];
250	break;
251	}
252	}
253	/* minpsd = -289 */
254	UPDATE_LEAK ();
255	mask = (fastleak < slowleak) ? fastleak : slowleak;
256	COMPUTE_MASK ();
257	i++;
258	j = startband;
259	do {
260	/* max(mask+4exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4exp */
261	/* min(mask+4exp)=-156=-(sgain-deltba-snroffset)>>5 /
262	bap[j] = (baptab+156)[mask + 4 * exp[j]];
263	} while (++j < endband);
264	} while (j < end);
265	}