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1 976f969b Zdenek Kabelac
/*
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 * bit_allocate.c
3 c947dec9 Zdenek Kabelac
 * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
4 976f969b Zdenek Kabelac
 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
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 *
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 * This file is part of a52dec, a free ATSC A-52 stream decoder.
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 * See http://liba52.sourceforge.net/ for updates.
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 *
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 * a52dec is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * a52dec 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
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
21 5509bffa Diego Biurrun
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 976f969b Zdenek Kabelac
 */
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#include "a52.h"
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#include "a52_internal.h"
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static int hthtab[3][50] = {
27
    {0x730, 0x730, 0x7c0, 0x800, 0x820, 0x840, 0x850, 0x850, 0x860, 0x860,
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     0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x890, 0x890,
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     0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900,
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     0x910, 0x910, 0x910, 0x910, 0x900, 0x8f0, 0x8c0, 0x870, 0x820, 0x7e0,
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     0x7a0, 0x770, 0x760, 0x7a0, 0x7c0, 0x7c0, 0x6e0, 0x400, 0x3c0, 0x3c0},
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    {0x710, 0x710, 0x7a0, 0x7f0, 0x820, 0x830, 0x840, 0x850, 0x850, 0x860,
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     0x860, 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880,
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     0x890, 0x890, 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8e0, 0x8f0,
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     0x900, 0x910, 0x910, 0x910, 0x910, 0x900, 0x8e0, 0x8b0, 0x870, 0x820,
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     0x7e0, 0x7b0, 0x760, 0x770, 0x7a0, 0x7c0, 0x780, 0x5d0, 0x3c0, 0x3c0},
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    {0x680, 0x680, 0x750, 0x7b0, 0x7e0, 0x810, 0x820, 0x830, 0x840, 0x850,
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     0x850, 0x850, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860,
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     0x870, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, 0x890, 0x8a0, 0x8b0,
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     0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, 0x910, 0x910, 0x910, 0x900, 0x8f0,
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     0x8d0, 0x8b0, 0x840, 0x7f0, 0x790, 0x760, 0x7a0, 0x7c0, 0x7b0, 0x720}
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};
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static int8_t baptab[305] = {
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    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
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    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
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    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
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    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
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    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
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    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,        /* 93 padding elems */
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    16, 16, 16, 16, 16, 16, 16, 16, 16, 14, 14, 14, 14, 14, 14, 14,
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    14, 12, 12, 12, 12, 11, 11, 11, 11, 10, 10, 10, 10,  9,  9,  9,
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     9,  8,  8,  8,  8,  7,  7,  7,  7,  6,  6,  6,  6,  5,  5,  5,
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     5,  4,  4, -3, -3,  3,  3,  3, -2, -2, -1, -1, -1, -1, -1,  0,
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     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0                                        /* 148 padding elems */
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};
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static int bndtab[30] = {21, 22,  23,  24,  25,  26,  27,  28,  31,  34,
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                         37, 40,  43,  46,  49,  55,  61,  67,  73,  79,
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                         85, 97, 109, 121, 133, 157, 181, 205, 229, 253};
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static int8_t latab[256] = {
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    -64, -63, -62, -61, -60, -59, -58, -57, -56, -55, -54, -53,
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    -52, -52, -51, -50, -49, -48, -47, -47, -46, -45, -44, -44,
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    -43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35,
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    -35, -34, -33, -33, -32, -32, -31, -30, -30, -29, -29, -28,
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    -28, -27, -27, -26, -26, -25, -25, -24, -24, -23, -23, -22,
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    -22, -21, -21, -21, -20, -20, -19, -19, -19, -18, -18, -18,
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    -17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14,
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    -13, -13, -13, -13, -12, -12, -12, -12, -11, -11, -11, -11,
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    -10, -10, -10, -10, -10,  -9,  -9,  -9,  -9,  -9,  -8,  -8,
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     -8,  -8,  -8,  -8,  -7,  -7,  -7,  -7,  -7,  -7,  -6,  -6,
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     -6,  -6,  -6,  -6,  -6,  -6,  -5,  -5,  -5,  -5,  -5,  -5,
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     -5,  -5,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,
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     -4,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,
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     -3,  -3,  -3,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,
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     -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -1,  -1,
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     -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,
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     -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,
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     -1,  -1,  -1,  -1,  -1,  -1,   0,   0,   0,   0,   0,   0,
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      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
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      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
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      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
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      0,   0,   0,   0
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};
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#define UPDATE_LEAK()                 \
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do {                                \
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    fastleak += fdecay;                \
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    if (fastleak > psd + fgain)        \
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        fastleak = psd + fgain;        \
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    slowleak += sdecay;                \
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    if (slowleak > psd + sgain)        \
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        slowleak = psd + sgain;        \
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} while (0)
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#define COMPUTE_MASK()                                \
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do {                                                \
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    if (psd > dbknee)                                \
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        mask -= (psd - dbknee) >> 2;                \
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    if (mask > hth [i >> halfrate])                \
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        mask = hth [i >> halfrate];                \
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    mask -= snroffset + 128 * deltba[i];        \
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    mask = (mask > 0) ? 0 : ((-mask) >> 5);        \
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    mask -= floor;                                \
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} while (0)
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void a52_bit_allocate (a52_state_t * state, ba_t * ba, int bndstart,
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                       int start, int end, int fastleak, int slowleak,
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                       expbap_t * expbap)
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{
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    static int slowgain[4] = {0x540, 0x4d8, 0x478, 0x410};
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    static int dbpbtab[4]  = {0xc00, 0x500, 0x300, 0x100};
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    static int floortab[8] = {0x910, 0x950, 0x990, 0x9d0,
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                              0xa10, 0xa90, 0xb10, 0x1400};
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    int i, j;
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    uint8_t * exp;
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    int8_t * bap;
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    int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;
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    int psd, mask;
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    int8_t * deltba;
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    int * hth;
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    int halfrate;
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    halfrate = state->halfrate;
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    fdecay = (63 + 20 * ((state->bai >> 7) & 3)) >> halfrate;        /* fdcycod */
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    fgain = 128 + 128 * (ba->bai & 7);                                /* fgaincod */
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    sdecay = (15 + 2 * (state->bai >> 9)) >> halfrate;                /* sdcycod */
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    sgain = slowgain[(state->bai >> 5) & 3];                        /* sgaincod */
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    dbknee = dbpbtab[(state->bai >> 3) & 3];                        /* dbpbcod */
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    hth = hthtab[state->fscod];
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    /*
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     * if there is no delta bit allocation, make deltba point to an area
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     * known to contain zeroes. baptab+156 here.
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     */
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    deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;
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    floor = floortab[state->bai & 7];                                /* floorcod */
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    snroffset = 960 - 64 * state->csnroffst - 4 * (ba->bai >> 3) + floor;
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    floor >>= 5;
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    exp = expbap->exp;
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    bap = expbap->bap;
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    i = bndstart;
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    j = start;
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    if (start == 0) {        /* not the coupling channel */
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        int lowcomp;
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161
        lowcomp = 0;
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        j = end - 1;
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        do {
164
            if (i < j) {
165
                if (exp[i+1] == exp[i] - 2)
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                    lowcomp = 384;
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                else if (lowcomp && (exp[i+1] > exp[i]))
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                    lowcomp -= 64;
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            }
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            psd = 128 * exp[i];
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            mask = psd + fgain + lowcomp;
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            COMPUTE_MASK ();
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            bap[i] = (baptab+156)[mask + 4 * exp[i]];
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            i++;
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        } while ((i < 3) || ((i < 7) && (exp[i] > exp[i-1])));
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        fastleak = psd + fgain;
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        slowleak = psd + sgain;
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        while (i < 7) {
180
            if (i < j) {
181
                if (exp[i+1] == exp[i] - 2)
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                    lowcomp = 384;
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                else if (lowcomp && (exp[i+1] > exp[i]))
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                    lowcomp -= 64;
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            }
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            psd = 128 * exp[i];
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            UPDATE_LEAK ();
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            mask = ((fastleak + lowcomp < slowleak) ?
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                    fastleak + lowcomp : slowleak);
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            COMPUTE_MASK ();
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            bap[i] = (baptab+156)[mask + 4 * exp[i]];
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            i++;
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        }
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        if (end == 7)        /* lfe channel */
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            return;
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        do {
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            if (exp[i+1] == exp[i] - 2)
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                lowcomp = 320;
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            else if (lowcomp && (exp[i+1] > exp[i]))
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                lowcomp -= 64;
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            psd = 128 * exp[i];
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            UPDATE_LEAK ();
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            mask = ((fastleak + lowcomp < slowleak) ?
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                    fastleak + lowcomp : slowleak);
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            COMPUTE_MASK ();
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            bap[i] = (baptab+156)[mask + 4 * exp[i]];
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            i++;
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        } while (i < 20);
211
212
        while (lowcomp > 128) {                /* two iterations maximum */
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            lowcomp -= 128;
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            psd = 128 * exp[i];
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            UPDATE_LEAK ();
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            mask = ((fastleak + lowcomp < slowleak) ?
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                    fastleak + lowcomp : slowleak);
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            COMPUTE_MASK ();
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            bap[i] = (baptab+156)[mask + 4 * exp[i]];
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            i++;
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        }
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        j = i;
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    }
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    do {
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        int startband, endband;
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228
        startband = j;
229 c947dec9 Zdenek Kabelac
        endband = (bndtab[i-20] < end) ? bndtab[i-20] : end;
230 976f969b Zdenek Kabelac
        psd = 128 * exp[j++];
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        while (j < endband) {
232
            int next, delta;
233
234
            next = 128 * exp[j++];
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            delta = next - psd;
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            switch (delta >> 9) {
237
            case -6: case -5: case -4: case -3: case -2:
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                psd = next;
239
                break;
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            case -1:
241
                psd = next + latab[(-delta) >> 1];
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                break;
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            case 0:
244
                psd += latab[delta >> 1];
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                break;
246
            }
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        }
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        /* minpsd = -289 */
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        UPDATE_LEAK ();
250
        mask = (fastleak < slowleak) ? fastleak : slowleak;
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        COMPUTE_MASK ();
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        i++;
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        j = startband;
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        do {
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            /* max(mask+4*exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4*exp */
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            /* min(mask+4*exp)=-156=-(sgain-deltba-snroffset)>>5 */
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            bap[j] = (baptab+156)[mask + 4 * exp[j]];
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        } while (++j < endband);
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    } while (j < end);
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}