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Diffstat (limited to 'ac3dec/bit_allocate.c')
-rw-r--r-- | ac3dec/bit_allocate.c | 494 |
1 files changed, 494 insertions, 0 deletions
diff --git a/ac3dec/bit_allocate.c b/ac3dec/bit_allocate.c new file mode 100644 index 00000000..053e09cd --- /dev/null +++ b/ac3dec/bit_allocate.c @@ -0,0 +1,494 @@ +/* + * 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 <stdlib.h> +#include <string.h> +#include "ac3.h" +#include "ac3_internal.h" + + + +static inline sint_16 logadd(sint_16 a,sint_16 b); +static sint_16 calc_lowcomp(sint_16 a,sint_16 b0,sint_16 b1,sint_16 bin); +static inline uint_16 min(sint_16 a,sint_16 b); +static inline uint_16 max(sint_16 a,sint_16 b); +static void ba_compute_psd(sint_16 start, sint_16 end, sint_16 exps[], + sint_16 psd[], sint_16 bndpsd[]); + +static void ba_compute_excitation(sint_16 start, sint_16 end,sint_16 fgain, + sint_16 fastleak, sint_16 slowleak, sint_16 is_lfe, sint_16 bndpsd[], + sint_16 excite[]); +static void ba_compute_mask(sint_16 start, sint_16 end, uint_16 fscod, + uint_16 deltbae, uint_16 deltnseg, uint_16 deltoffst[], uint_16 deltba[], + uint_16 deltlen[], sint_16 excite[], sint_16 mask[]); +static void ba_compute_bap(sint_16 start, sint_16 end, sint_16 snroffset, + sint_16 psd[], sint_16 mask[], sint_16 bap[]); + +/* Misc LUTs for bit allocation process */ + +static sint_16 slowdec[] = { 0x0f, 0x11, 0x13, 0x15 }; +static sint_16 fastdec[] = { 0x3f, 0x53, 0x67, 0x7b }; +static sint_16 slowgain[] = { 0x540, 0x4d8, 0x478, 0x410 }; +static sint_16 dbpbtab[] = { 0x000, 0x700, 0x900, 0xb00 }; + +static uint_16 floortab[] = { 0x2f0, 0x2b0, 0x270, 0x230, 0x1f0, 0x170, 0x0f0, 0xf800 }; +static sint_16 fastgain[] = { 0x080, 0x100, 0x180, 0x200, 0x280, 0x300, 0x380, 0x400 }; + + +static sint_16 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 sint_16 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 sint_16 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 sint_16 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 sint_16 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 sint_16 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 sint_16 sdecay; +static sint_16 fdecay; +static sint_16 sgain; +static sint_16 dbknee; +static sint_16 floor; +static sint_16 psd[256]; +static sint_16 bndpsd[256]; +static sint_16 excite[256]; +static sint_16 mask[256]; + +static inline uint_16 +max(sint_16 a,sint_16 b) +{ + return (a > b ? a : b); +} + +static inline uint_16 +min(sint_16 a,sint_16 b) +{ + return (a < b ? a : b); +} + +static inline sint_16 +logadd(sint_16 a,sint_16 b) +{ + sint_16 c; + sint_16 address; + + c = a - b; + address = min((abs(c) >> 1), 255); + + if (c >= 0) + return(a + latab[address]); + else + return(b + latab[address]); +} + + +void bit_allocate(uint_16 fscod, bsi_t *bsi, audblk_t *audblk) +{ + uint_16 i; + sint_16 fgain; + sint_16 snroffset; + sint_16 start; + sint_16 end; + sint_16 fastleak; + sint_16 slowleak; + + /* Only perform bit_allocation if the exponents have changed or we + * have new sideband information */ + if (audblk->chexpstr[0] == 0 && audblk->chexpstr[1] == 0 && + audblk->chexpstr[2] == 0 && audblk->chexpstr[3] == 0 && + audblk->chexpstr[4] == 0 && audblk->cplexpstr == 0 && + audblk->lfeexpstr == 0 && audblk->baie == 0 && + audblk->snroffste == 0 && audblk->deltbaie == 0) + return; + + /* 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]; + + /* if all the SNR offset constants are zero then the whole block is zero */ + if(!audblk->csnroffst && !audblk->fsnroffst[0] && + !audblk->fsnroffst[1] && !audblk->fsnroffst[2] && + !audblk->fsnroffst[3] && !audblk->fsnroffst[4] && + !audblk->cplfsnroffst && !audblk->lfefsnroffst) + { + memset(audblk->fbw_bap,0,sizeof(uint_16) * 256 * 5); + memset(audblk->cpl_bap,0,sizeof(uint_16) * 256); + memset(audblk->lfe_bap,0,sizeof(uint_16) * 7); + return; + } + + + for(i = 0; i < bsi->nfchans; i++) + { + start = 0; + end = audblk->endmant[i] ; + fgain = fastgain[audblk->fgaincod[i]]; + snroffset = (((audblk->csnroffst - 15) << 4) + audblk->fsnroffst[i]) << 2 ; + fastleak = 0; + slowleak = 0; + + ba_compute_psd(start, end, audblk->fbw_exp[i], psd, bndpsd); + + ba_compute_excitation(start, end , fgain, fastleak, slowleak, 0, bndpsd, excite); + + ba_compute_mask(start, end, fscod, audblk->deltbae[i], audblk->deltnseg[i], + audblk->deltoffst[i], audblk->deltba[i], audblk->deltlen[i], excite, mask); + + ba_compute_bap(start, end, snroffset, psd, mask, audblk->fbw_bap[i]); + } + + if(audblk->cplinu) + { + start = audblk->cplstrtmant; + end = audblk->cplendmant; + fgain = fastgain[audblk->cplfgaincod]; + snroffset = (((audblk->csnroffst - 15) << 4) + audblk->cplfsnroffst) << 2 ; + fastleak = (audblk->cplfleak << 8) + 768; + slowleak = (audblk->cplsleak << 8) + 768; + + ba_compute_psd(start, end, audblk->cpl_exp, psd, bndpsd); + + ba_compute_excitation(start, end , fgain, fastleak, slowleak, 0, bndpsd, excite); + + ba_compute_mask(start, end, fscod, audblk->cpldeltbae, audblk->cpldeltnseg, + audblk->cpldeltoffst, audblk->cpldeltba, audblk->cpldeltlen, excite, mask); + + ba_compute_bap(start, end, snroffset, psd, mask, audblk->cpl_bap); + } + + if(bsi->lfeon) + { + start = 0; + end = 7; + fgain = fastgain[audblk->lfefgaincod]; + snroffset = (((audblk->csnroffst - 15) << 4) + audblk->lfefsnroffst) << 2 ; + fastleak = 0; + slowleak = 0; + + ba_compute_psd(start, end, audblk->lfe_exp, psd, bndpsd); + + ba_compute_excitation(start, end , fgain, fastleak, slowleak, 1, bndpsd, excite); + + /* Perform no delta bit allocation for lfe */ + ba_compute_mask(start, end, fscod, 2, 0, 0, 0, 0, excite, mask); + + ba_compute_bap(start, end, snroffset, psd, mask, audblk->lfe_bap); + } +} + + +static void ba_compute_psd(sint_16 start, sint_16 end, sint_16 exps[], + sint_16 psd[], sint_16 bndpsd[]) +{ + int bin,i,j,k; + sint_16 lastbin = 0; + + /* Map the exponents into dBs */ + for (bin=start; bin<end; bin++) + { + psd[bin] = (3072 - (exps[bin] << 7)); + } + + /* Integrate the psd function over each bit allocation band */ + j = start; + k = masktab[start]; + + do + { + lastbin = min(bndtab[k] + bndsz[k], end); + bndpsd[k] = psd[j]; + j++; + + for (i = j; i < lastbin; i++) + { + bndpsd[k] = logadd(bndpsd[k], psd[j]); + j++; + } + + k++; + } while (end > lastbin); +} + +static void ba_compute_excitation(sint_16 start, sint_16 end,sint_16 fgain, + sint_16 fastleak, sint_16 slowleak, sint_16 is_lfe, sint_16 bndpsd[], + sint_16 excite[]) +{ + int bin; + sint_16 bndstrt; + sint_16 bndend; + sint_16 lowcomp = 0; + sint_16 begin = 0; + + /* Compute excitation function */ + bndstrt = masktab[start]; + bndend = masktab[end - 1] + 1; + + if (bndstrt == 0) /* For fbw and lfe channels */ + { + lowcomp = calc_lowcomp(lowcomp, bndpsd[0], bndpsd[1], 0); + excite[0] = bndpsd[0] - fgain - lowcomp; + lowcomp = calc_lowcomp(lowcomp, bndpsd[1], bndpsd[2], 1); + excite[1] = bndpsd[1] - fgain - lowcomp; + begin = 7 ; + + /* Note: Do not call calc_lowcomp() for the last band of the lfe channel, (bin = 6) */ + for (bin = 2; bin < 7; bin++) + { + if (!(is_lfe && (bin == 6))) + lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin+1], bin); + fastleak = bndpsd[bin] - fgain; + slowleak = bndpsd[bin] - sgain; + excite[bin] = fastleak - lowcomp; + + if (!(is_lfe && (bin == 6))) + { + if (bndpsd[bin] <= bndpsd[bin+1]) + { + begin = bin + 1 ; + break; + } + } + } + + for (bin = begin; bin < min(bndend, 22); bin++) + { + if (!(is_lfe && (bin == 6))) + lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin+1], bin); + fastleak -= fdecay ; + fastleak = max(fastleak, bndpsd[bin] - fgain); + slowleak -= sdecay ; + slowleak = max(slowleak, bndpsd[bin] - sgain); + excite[bin] = max(fastleak - lowcomp, slowleak); + } + begin = 22; + } + else /* For coupling channel */ + { + begin = bndstrt; + } + + for (bin = begin; bin < bndend; bin++) + { + fastleak -= fdecay; + fastleak = max(fastleak, bndpsd[bin] - fgain); + slowleak -= sdecay; + slowleak = max(slowleak, bndpsd[bin] - sgain); + excite[bin] = max(fastleak, slowleak) ; + } +} + +static void ba_compute_mask(sint_16 start, sint_16 end, uint_16 fscod, + uint_16 deltbae, uint_16 deltnseg, uint_16 deltoffst[], uint_16 deltba[], + uint_16 deltlen[], sint_16 excite[], sint_16 mask[]) +{ + int bin,k; + sint_16 bndstrt; + sint_16 bndend; + sint_16 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)) + { + sint_16 band = 0; + sint_16 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(sint_16 start, sint_16 end, sint_16 snroffset, + sint_16 psd[], sint_16 mask[], sint_16 bap[]) +{ + int i,j,k; + sint_16 lastbin = 0; + sint_16 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 = (psd[i] - mask[j]) >> 5; + address = min(63, max(0, address)); + bap[i] = baptab[address]; + i++; + } + j++; + } while (end > lastbin); +} + +static sint_16 +calc_lowcomp(sint_16 a,sint_16 b0,sint_16 b1,sint_16 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); +} + |