/* * bit_allocate.c * * Copyright (C) Aaron Holtzman - May 1999 * * This file is part of ac3dec, a free Dolby AC-3 stream decoder. * * ac3dec 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, or (at your option) * any later version. * * ac3dec 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 GNU Make; see the file COPYING. If not, write to * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. * */ #include #include #include "ac3.h" #include "ac3_internal.h" #include "bit_allocate.h" static int16_t calc_lowcomp(int16_t a,int16_t b0,int16_t b1,int16_t bin); static inline uint16_t min(int16_t a,int16_t b); static inline uint16_t max(int16_t a,int16_t b); static void ba_compute_mask(int16_t start, int16_t end, uint16_t fscod, uint16_t deltbae, uint16_t deltnseg, uint16_t deltoffst[], uint16_t deltba[], uint16_t deltlen[], int16_t excite[], int16_t mask[]); static void ba_compute_bap(int16_t start, int16_t end, int16_t snroffset, int8_t exp[], int16_t mask[], int16_t bap[]); /* Misc LUTs for bit allocation process */ static int16_t slowdec[] = { 0x0f, 0x11, 0x13, 0x15 }; static int16_t fastdec[] = { 0x3f, 0x53, 0x67, 0x7b }; static int16_t slowgain[] = { 0x540, 0x4d8, 0x478, 0x410 }; static int16_t dbpbtab[] = { 0x000, 0x700, 0x900, 0xb00 }; static uint16_t floortab[] = { 0x2f0, 0x2b0, 0x270, 0x230, 0x1f0, 0x170, 0x0f0, 0xf800 }; static int16_t fastgain[] = { 0x080, 0x100, 0x180, 0x200, 0x280, 0x300, 0x380, 0x400 }; static int16_t bndtab[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 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 }; static int16_t bndsz[] = { 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, 3, 3, 3, 3, 3, 3, 3, 6, 6, 6, 6, 6, 6, 12, 12, 12, 12, 24, 24, 24, 24, 24 }; static int16_t masktab[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 28, 28, 29, 29, 29, 30, 30, 30, 31, 31, 31, 32, 32, 32, 33, 33, 33, 34, 34, 34, 35, 35, 35, 35, 35, 35, 36, 36, 36, 36, 36, 36, 37, 37, 37, 37, 37, 37, 38, 38, 38, 38, 38, 38, 39, 39, 39, 39, 39, 39, 40, 40, 40, 40, 40, 40, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 0, 0, 0 }; static int16_t latab[] = { 0x0040, 0x003f, 0x003e, 0x003d, 0x003c, 0x003b, 0x003a, 0x0039, 0x0038, 0x0037, 0x0036, 0x0035, 0x0034, 0x0034, 0x0033, 0x0032, 0x0031, 0x0030, 0x002f, 0x002f, 0x002e, 0x002d, 0x002c, 0x002c, 0x002b, 0x002a, 0x0029, 0x0029, 0x0028, 0x0027, 0x0026, 0x0026, 0x0025, 0x0024, 0x0024, 0x0023, 0x0023, 0x0022, 0x0021, 0x0021, 0x0020, 0x0020, 0x001f, 0x001e, 0x001e, 0x001d, 0x001d, 0x001c, 0x001c, 0x001b, 0x001b, 0x001a, 0x001a, 0x0019, 0x0019, 0x0018, 0x0018, 0x0017, 0x0017, 0x0016, 0x0016, 0x0015, 0x0015, 0x0015, 0x0014, 0x0014, 0x0013, 0x0013, 0x0013, 0x0012, 0x0012, 0x0012, 0x0011, 0x0011, 0x0011, 0x0010, 0x0010, 0x0010, 0x000f, 0x000f, 0x000f, 0x000e, 0x000e, 0x000e, 0x000d, 0x000d, 0x000d, 0x000d, 0x000c, 0x000c, 0x000c, 0x000c, 0x000b, 0x000b, 0x000b, 0x000b, 0x000a, 0x000a, 0x000a, 0x000a, 0x000a, 0x0009, 0x0009, 0x0009, 0x0009, 0x0009, 0x0008, 0x0008, 0x0008, 0x0008, 0x0008, 0x0008, 0x0007, 0x0007, 0x0007, 0x0007, 0x0007, 0x0007, 0x0006, 0x0006, 0x0006, 0x0006, 0x0006, 0x0006, 0x0006, 0x0006, 0x0005, 0x0005, 0x0005, 0x0005, 0x0005, 0x0005, 0x0005, 0x0005, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0004, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0002, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0001, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}; static int16_t hth[][50] = {{ 0x04d0, 0x04d0, 0x0440, 0x0400, 0x03e0, 0x03c0, 0x03b0, 0x03b0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x0390, 0x0390, 0x0390, 0x0380, 0x0380, 0x0370, 0x0370, 0x0360, 0x0360, 0x0350, 0x0350, 0x0340, 0x0340, 0x0330, 0x0320, 0x0310, 0x0300, 0x02f0, 0x02f0, 0x02f0, 0x02f0, 0x0300, 0x0310, 0x0340, 0x0390, 0x03e0, 0x0420, 0x0460, 0x0490, 0x04a0, 0x0460, 0x0440, 0x0440, 0x0520, 0x0800, 0x0840, 0x0840 }, { 0x04f0, 0x04f0, 0x0460, 0x0410, 0x03e0, 0x03d0, 0x03c0, 0x03b0, 0x03b0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x0390, 0x0390, 0x0390, 0x0380, 0x0380, 0x0380, 0x0370, 0x0370, 0x0360, 0x0360, 0x0350, 0x0350, 0x0340, 0x0340, 0x0320, 0x0310, 0x0300, 0x02f0, 0x02f0, 0x02f0, 0x02f0, 0x0300, 0x0320, 0x0350, 0x0390, 0x03e0, 0x0420, 0x0450, 0x04a0, 0x0490, 0x0460, 0x0440, 0x0480, 0x0630, 0x0840, 0x0840 }, { 0x0580, 0x0580, 0x04b0, 0x0450, 0x0420, 0x03f0, 0x03e0, 0x03d0, 0x03c0, 0x03b0, 0x03b0, 0x03b0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x03a0, 0x0390, 0x0390, 0x0390, 0x0390, 0x0380, 0x0380, 0x0380, 0x0370, 0x0360, 0x0350, 0x0340, 0x0330, 0x0320, 0x0310, 0x0300, 0x02f0, 0x02f0, 0x02f0, 0x0300, 0x0310, 0x0330, 0x0350, 0x03c0, 0x0410, 0x0470, 0x04a0, 0x0460, 0x0440, 0x0450, 0x04e0 }}; static int16_t baptab[] = { 0, 1, 1, 1, 1, 1, 2, 2, 3, 3, 3, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15 }; static int16_t sdecay; static int16_t fdecay; static int16_t sgain; static int16_t dbknee; static int16_t floor; static int16_t bndpsd[256]; static int16_t excite[256]; static int16_t mask[256]; static inline uint16_t max(int16_t a,int16_t b) { return (a > b ? a : b); } static inline uint16_t min(int16_t a,int16_t b) { return (a < b ? a : b); } void bit_allocate(int fscod, audblk_t * audblk, ac3_ba_t * ba, uint16_t start, uint16_t end, int16_t fastleak, int16_t slowleak, uint8_t * exp, uint16_t * bap, int is_lfe) { int16_t fgain; uint16_t snroffset; int i, j; int bndstrt; int lowcomp; /* Do some setup before we do the bit alloc */ sdecay = slowdec[audblk->sdcycod]; fdecay = fastdec[audblk->fdcycod]; sgain = slowgain[audblk->sgaincod]; dbknee = dbpbtab[audblk->dbpbcod]; floor = floortab[audblk->floorcod]; fgain = fastgain[ba->fgaincod]; snroffset = 64 * audblk->csnroffst + 4 * ba->fsnroffst - 960; i = start; j = bndstrt = masktab[start]; do { int psd, lastbin; lastbin = min (bndtab[j] + bndsz[j], end); psd = 128 * exp[i++]; while (i < lastbin) { int next, delta; next = 128 * exp[i++]; 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; } } bndpsd[j++] = 3072 - psd; } while (i < end); // j = bndend j--; i = bndstrt; lowcomp = 0; if (i == 0) { // not the coupling channel do { if (i < j) { if (bndpsd[i+1] == bndpsd[i] + 256) lowcomp = 384; else if (lowcomp && (bndpsd[i+1] < bndpsd[i])) lowcomp -= 64; } excite[i++] = bndpsd[i] - fgain - lowcomp; } while ((i < 3) || ((i < 7) && (bndpsd[i] < bndpsd[i-1]))); fastleak = bndpsd[i-1] - fgain; slowleak = bndpsd[i-1] - sgain; while (i < 7) { if (i < j) { if (bndpsd[i+1] == bndpsd[i] + 256) lowcomp = 384; else if (lowcomp && (bndpsd[i+1] < bndpsd[i])) lowcomp -= 64; } fastleak -= fdecay; if (fastleak < bndpsd[i] - fgain) fastleak = bndpsd[i] - fgain; slowleak -= sdecay; if (slowleak < bndpsd[i] - sgain) slowleak = bndpsd[i] - sgain; excite[i++] = ((fastleak - lowcomp > slowleak) ? fastleak - lowcomp : slowleak); } if (i > j) // lfe channel goto done_excite; do { if (bndpsd[i+1] == bndpsd[i] + 256) lowcomp = 320; else if (lowcomp && (bndpsd[i+1] < bndpsd[i])) lowcomp -= 64; fastleak -= fdecay; if (fastleak < bndpsd[i] - fgain) fastleak = bndpsd[i] - fgain; slowleak -= sdecay; if (slowleak < bndpsd[i] - sgain) slowleak = bndpsd[i] - sgain; excite[i++] = ((fastleak - lowcomp > slowleak) ? fastleak - lowcomp : slowleak); } while (i < 20); while (lowcomp > 128) { // two iterations maximum lowcomp -= 128; fastleak -= fdecay; if (fastleak < bndpsd[i] - fgain) fastleak = bndpsd[i] - fgain; slowleak -= sdecay; if (slowleak < bndpsd[i] - sgain) slowleak = bndpsd[i] - sgain; excite[i++] = ((fastleak - lowcomp > slowleak) ? fastleak - lowcomp : slowleak); } } do { fastleak -= fdecay; if (fastleak < bndpsd[i] - fgain) fastleak = bndpsd[i] - fgain; slowleak -= sdecay; if (slowleak < bndpsd[i] - sgain) slowleak = bndpsd[i] - sgain; excite[i++] = (fastleak > slowleak) ? fastleak : slowleak; } while (i <= j); done_excite: ba_compute_mask(start, end, fscod, ba->deltbae, ba->deltnseg, ba->deltoffst, ba->deltba, ba->deltlen, excite, mask); ba_compute_bap(start, end, snroffset, exp, mask, bap); } static void ba_compute_mask(int16_t start, int16_t end, uint16_t fscod, uint16_t deltbae, uint16_t deltnseg, uint16_t deltoffst[], uint16_t deltba[], uint16_t deltlen[], int16_t excite[], int16_t mask[]) { int bin,k; int16_t bndstrt; int16_t bndend; int16_t delta; bndstrt = masktab[start]; bndend = masktab[end - 1] + 1; /* Compute the masking curve */ for (bin = bndstrt; bin < bndend; bin++) { if (bndpsd[bin] < dbknee) excite[bin] += ((dbknee - bndpsd[bin]) >> 2); mask[bin] = max(excite[bin], hth[fscod][bin]); } /* Perform delta bit modulation if necessary */ if ((deltbae == DELTA_BIT_REUSE) || (deltbae == DELTA_BIT_NEW)) { int16_t band = 0; int16_t seg = 0; for (seg = 0; seg < deltnseg+1; seg++) { band += deltoffst[seg]; if (deltba[seg] >= 4) delta = (deltba[seg] - 3) << 7; else delta = (deltba[seg] - 4) << 7; for (k = 0; k < deltlen[seg]; k++) { mask[band] += delta; band++; } } } } static void ba_compute_bap(int16_t start, int16_t end, int16_t snroffset, int8_t exps[], int16_t mask[], int16_t bap[]) { int i,j,k; int16_t lastbin = 0; int16_t address = 0; /* Compute the bit allocation pointer for each bin */ i = start; j = masktab[start]; do { lastbin = min(bndtab[j] + bndsz[j], end); mask[j] -= snroffset; mask[j] -= floor; if (mask[j] < 0) mask[j] = 0; mask[j] &= 0x1fe0; mask[j] += floor; for (k = i; k < lastbin; k++) { address = (3072 - 128 * exps[i] - mask[j]) >> 5; address = min(63, max(0, address)); bap[i] = baptab[address]; i++; } j++; } while (end > lastbin); } static int16_t calc_lowcomp(int16_t a,int16_t b0,int16_t b1,int16_t bin) { if (bin < 7) { if ((b0 + 256) == b1) a = 384; else if (b0 > b1) a = max(0, a - 64); } else if (bin < 20) { if ((b0 + 256) == b1) a = 320; else if (b0 > b1) a = max(0, a - 64) ; } else a = max(0, a - 128); return(a); }