liba52/bit_allocate.c

   1 /*
   2  * bit_allocate.c
   3  * Copyright (C) 2000-2001 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 bit_allocate (a52_state_t * state, a52_ba_t * ba, int bndstart,
 125                    int start, int end, int fastleak, int slowleak,
 126                    uint8_t * exp, int8_t * bap)
 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     int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;
 135     int psd, mask;
 136     int8_t * deltba;
 137     int * hth;
 138     int halfrate;
 139
 140     halfrate = state->halfrate;
 141     fdecay = (63 + 20 * state->fdcycod) >> halfrate;
 142     fgain = 128 + 128 * ba->fgaincod;
 143     sdecay = (15 + 2 * state->sdcycod) >> halfrate;
 144     sgain = slowgain[state->sgaincod];
 145     dbknee = dbpbtab[state->dbpbcod];
 146     hth = hthtab[state->fscod];
 147     /*
 148      * if there is no delta bit allocation, make deltba point to an area
 149      * known to contain zeroes. baptab+156 here.
 150      */
 151     deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;
 152     floor = floortab[state->floorcod];
 153     snroffset = 960 - 64 * state->csnroffst - 4 * ba->fsnroffst + floor;
 154     floor >>= 5;
 155
 156     i = bndstart;
 157     j = start;
 158     if (start == 0) {   /* not the coupling channel */
 159         int lowcomp;
 160
 161         lowcomp = 0;
 162         j = end - 1;
 163         do {
 164             if (i < j) {
 165                 if (exp[i+1] == exp[i] - 2)
 166                     lowcomp = 384;
 167                 else if (lowcomp && (exp[i+1] > exp[i]))
 168                     lowcomp -= 64;
 169             }
 170             psd = 128 * exp[i];
 171             mask = psd + fgain + lowcomp;
 172             COMPUTE_MASK ();
 173             bap[i] = (baptab+156)[mask + 4 * exp[i]];
 174             i++;
 175         } while ((i < 3) || ((i < 7) && (exp[i] > exp[i-1])));
 176         fastleak = psd + fgain;
 177         slowleak = psd + sgain;
 178
 179         while (i < 7) {
 180             if (i < j) {
 181                 if (exp[i+1] == exp[i] - 2)
 182                     lowcomp = 384;
 183                 else if (lowcomp && (exp[i+1] > exp[i]))
 184                     lowcomp -= 64;
 185             }
 186             psd = 128 * exp[i];
 187             UPDATE_LEAK ();
 188             mask = ((fastleak + lowcomp < slowleak) ?
 189                     fastleak + lowcomp : slowleak);
 190             COMPUTE_MASK ();
 191             bap[i] = (baptab+156)[mask + 4 * exp[i]];
 192             i++;
 193         }
 194
 195         if (end == 7)   /* lfe channel */
 196             return;
 197
 198         do {
 199             if (exp[i+1] == exp[i] - 2)
 200                 lowcomp = 320;
 201             else if (lowcomp && (exp[i+1] > exp[i]))
 202                 lowcomp -= 64;
 203             psd = 128 * exp[i];
 204             UPDATE_LEAK ();
 205             mask = ((fastleak + lowcomp < slowleak) ?
 206                     fastleak + lowcomp : slowleak);
 207             COMPUTE_MASK ();
 208             bap[i] = (baptab+156)[mask + 4 * exp[i]];
 209             i++;
 210         } while (i < 20);
 211
 212         while (lowcomp > 128) {         /* two iterations maximum */
 213             lowcomp -= 128;
 214             psd = 128 * exp[i];
 215             UPDATE_LEAK ();
 216             mask = ((fastleak + lowcomp < slowleak) ?
 217                     fastleak + lowcomp : slowleak);
 218             COMPUTE_MASK ();
 219             bap[i] = (baptab+156)[mask + 4 * exp[i]];
 220             i++;
 221         }
 222         j = i;
 223     }
 224
 225     do {
 226         int startband, endband;
 227
 228         startband = j;
 229         endband = ((bndtab-20)[i] < end) ? (bndtab-20)[i] : end;
 230         psd = 128 * exp[j++];
 231         while (j < endband) {
 232             int next, delta;
 233
 234             next = 128 * exp[j++];
 235             delta = next - psd;
 236             switch (delta >> 9) {
 237             case -6: case -5: case -4: case -3: case -2:
 238                 psd = next;
 239                 break;
 240             case -1:
 241                 psd = next + latab[(-delta) >> 1];
 242                 break;
 243             case 0:
 244                 psd += latab[delta >> 1];
 245                 break;
 246             }
 247         }
 248         /* minpsd = -289 */
 249         UPDATE_LEAK ();
 250         mask = (fastleak < slowleak) ? fastleak : slowleak;
 251         COMPUTE_MASK ();
 252         i++;
 253         j = startband;
 254         do {
 255             /* max(mask+4*exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4*exp */
 256             /* min(mask+4*exp)=-156=-(sgain-deltba-snroffset)>>5 */
 257             bap[j] = (baptab+156)[mask + 4 * exp[j]];
 258         } while (++j < endband);
 259     } while (j < end);
 260 }