From bff17fb1d0e39583e44ba93ea214d7434ecef2ce Mon Sep 17 00:00:00 2001 From: Klaus Schmidinger Date: Fri, 3 Aug 2001 14:18:08 +0200 Subject: Added support for replaying DVDs --- ac3dec/coeff.c | 353 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 353 insertions(+) create mode 100644 ac3dec/coeff.c (limited to 'ac3dec/coeff.c') diff --git a/ac3dec/coeff.c b/ac3dec/coeff.c new file mode 100644 index 00000000..b9f03ff6 --- /dev/null +++ b/ac3dec/coeff.c @@ -0,0 +1,353 @@ +/* + * coeff.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 "decode.h" +#include "bitstream.h" +#include "dither.h" +#include "coeff.h" + +// +//Lookup tables of 0.15 two's complement quantization values +// +static const uint_16 q_1[3] = +{ + ( -2 << 15)/3, 0,( 2 << 15)/3 +}; + +static const uint_16 q_2[5] = +{ + ( -4 << 15)/5,( -2 << 15)/5, 0, + ( 2 << 15)/5,( 4 << 15)/5 +}; + +static const uint_16 q_3[7] = +{ + ( -6 << 15)/7,( -4 << 15)/7,( -2 << 15)/7, 0, + ( 2 << 15)/7,( 4 << 15)/7,( 6 << 15)/7 +}; + +static const uint_16 q_4[11] = +{ + (-10 << 15)/11,(-8 << 15)/11,(-6 << 15)/11, ( -4 << 15)/11,(-2 << 15)/11, 0, + ( 2 << 15)/11,( 4 << 15)/11,( 6 << 15)/11, ( 8 << 15)/11,(10 << 15)/11 +}; + +static const uint_16 q_5[15] = +{ + (-14 << 15)/15,(-12 << 15)/15,(-10 << 15)/15, + ( -8 << 15)/15,( -6 << 15)/15,( -4 << 15)/15, + ( -2 << 15)/15, 0 ,( 2 << 15)/15, + ( 4 << 15)/15,( 6 << 15)/15,( 8 << 15)/15, + ( 10 << 15)/15,( 12 << 15)/15,( 14 << 15)/15 +}; + +// +// Scale factors for convert_to_float +// + +static const uint_32 u32_scale_factors[25] = +{ + 0x38000000, //2 ^ -(0 + 15) + 0x37800000, //2 ^ -(1 + 15) + 0x37000000, //2 ^ -(2 + 15) + 0x36800000, //2 ^ -(3 + 15) + 0x36000000, //2 ^ -(4 + 15) + 0x35800000, //2 ^ -(5 + 15) + 0x35000000, //2 ^ -(6 + 15) + 0x34800000, //2 ^ -(7 + 15) + 0x34000000, //2 ^ -(8 + 15) + 0x33800000, //2 ^ -(9 + 15) + 0x33000000, //2 ^ -(10 + 15) + 0x32800000, //2 ^ -(11 + 15) + 0x32000000, //2 ^ -(12 + 15) + 0x31800000, //2 ^ -(13 + 15) + 0x31000000, //2 ^ -(14 + 15) + 0x30800000, //2 ^ -(15 + 15) + 0x30000000, //2 ^ -(16 + 15) + 0x2f800000, //2 ^ -(17 + 15) + 0x2f000000, //2 ^ -(18 + 15) + 0x2e800000, //2 ^ -(19 + 15) + 0x2e000000, //2 ^ -(20 + 15) + 0x2d800000, //2 ^ -(21 + 15) + 0x2d000000, //2 ^ -(22 + 15) + 0x2c800000, //2 ^ -(23 + 15) + 0x2c000000 //2 ^ -(24 + 15) +}; + +static float *scale_factor = (float*)u32_scale_factors; + +//These store the persistent state of the packed mantissas +static uint_16 m_1[3]; +static uint_16 m_2[3]; +static uint_16 m_4[2]; +static uint_16 m_1_pointer; +static uint_16 m_2_pointer; +static uint_16 m_4_pointer; + +//Conversion from bap to number of bits in the mantissas +//zeros account for cases 0,1,2,4 which are special cased +static uint_16 qnttztab[16] = { 0, 0, 0, 3, 0 , 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16}; + +static void coeff_reset(void); +static sint_16 coeff_get_mantissa(uint_16 bap, uint_16 dithflag); +static void coeff_uncouple_ch(float samples[],bsi_t *bsi,audblk_t *audblk,uint_32 ch); + +// +// Convert a 0.15 fixed point number into IEEE single +// precision floating point and scale by 2^-exp +// +static inline float +convert_to_float(uint_16 exp, sint_16 mantissa) +{ + float x; + + //the scale by 2^-15 is built into the scale factor table + x = mantissa * scale_factor[exp]; + + return x; +} + +void +coeff_unpack(bsi_t *bsi, audblk_t *audblk, stream_samples_t samples) +{ + uint_16 i,j; + uint_32 done_cpl = 0; + sint_16 mantissa; + + coeff_reset(); + + for(i=0; i< bsi->nfchans; i++) + { + for(j=0; j < audblk->endmant[i]; j++) + { + mantissa = coeff_get_mantissa(audblk->fbw_bap[i][j],audblk->dithflag[i]); + samples[i][j] = convert_to_float(audblk->fbw_exp[i][j],mantissa); + } + + if(audblk->cplinu && audblk->chincpl[i] && !(done_cpl)) + { + // ncplmant is equal to 12 * ncplsubnd + // Don't dither coupling channel until channel separation so that + // interchannel noise is uncorrelated + for(j=audblk->cplstrtmant; j < audblk->cplendmant; j++) + audblk->cplmant[j] = coeff_get_mantissa(audblk->cpl_bap[j],0); + done_cpl = 1; + } + } + + //uncouple the channel if necessary + if(audblk->cplinu) + { + for(i=0; i< bsi->nfchans; i++) + { + if(audblk->chincpl[i]) + coeff_uncouple_ch(samples[i],bsi,audblk,i); + } + + } + + if(bsi->lfeon) + { + // There are always 7 mantissas for lfe, no dither for lfe + for(j=0; j < 7 ; j++) + { + mantissa = coeff_get_mantissa(audblk->lfe_bap[j],0); + samples[5][j] = convert_to_float(audblk->lfe_exp[j],mantissa); + } + } +} + +// +//Fetch a mantissa from the bitstream +// +//The mantissa returned is a signed 0.15 fixed point number +// +static sint_16 +coeff_get_mantissa(uint_16 bap, uint_16 dithflag) +{ + uint_16 mantissa; + uint_16 group_code; + + //If the bap is 0-5 then we have special cases to take care of + switch(bap) + { + case 0: + if(dithflag) + mantissa = dither_gen(); + else + mantissa = 0; + break; + + case 1: + if(m_1_pointer > 2) + { + group_code = bitstream_get(5); + + if(group_code > 26) + goto error; + + m_1[0] = group_code / 9; + m_1[1] = (group_code % 9) / 3; + m_1[2] = (group_code % 9) % 3; + m_1_pointer = 0; + } + mantissa = m_1[m_1_pointer++]; + mantissa = q_1[mantissa]; + break; + case 2: + + if(m_2_pointer > 2) + { + group_code = bitstream_get(7); + + if(group_code > 124) + goto error; + + m_2[0] = group_code / 25; + m_2[1] = (group_code % 25) / 5 ; + m_2[2] = (group_code % 25) % 5 ; + m_2_pointer = 0; + } + mantissa = m_2[m_2_pointer++]; + mantissa = q_2[mantissa]; + break; + + case 3: + mantissa = bitstream_get(3); + + if(mantissa > 6) + goto error; + + mantissa = q_3[mantissa]; + break; + + case 4: + if(m_4_pointer > 1) + { + group_code = bitstream_get(7); + + if(group_code > 120) + goto error; + + m_4[0] = group_code / 11; + m_4[1] = group_code % 11; + m_4_pointer = 0; + } + mantissa = m_4[m_4_pointer++]; + mantissa = q_4[mantissa]; + break; + + case 5: + mantissa = bitstream_get(4); + + if(mantissa > 14) + goto error; + + mantissa = q_5[mantissa]; + break; + + default: + mantissa = bitstream_get(qnttztab[bap]); + mantissa <<= 16 - qnttztab[bap]; + } + + return mantissa; + + + +error: + if(!error_flag) + fprintf(stderr,"** Invalid mantissa - skipping frame **\n"); + error_flag = 1; + + return 0; +} + +// +// Reset the mantissa state +// +static void +coeff_reset(void) +{ + m_1[2] = m_1[1] = m_1[0] = 0; + m_2[2] = m_2[1] = m_2[0] = 0; + m_4[1] = m_4[0] = 0; + m_1_pointer = m_2_pointer = m_4_pointer = 3; +} + +// +// Uncouple the coupling channel into a fbw channel +// +static void +coeff_uncouple_ch(float samples[],bsi_t *bsi,audblk_t *audblk,uint_32 ch) +{ + uint_32 bnd = 0; + uint_32 sub_bnd = 0; + uint_32 i,j; + float cpl_coord = 1.0; + uint_32 cpl_exp_tmp; + uint_32 cpl_mant_tmp; + sint_16 mantissa; + + + for(i=audblk->cplstrtmant;icplendmant;) + { + if(!audblk->cplbndstrc[sub_bnd++]) + { + cpl_exp_tmp = audblk->cplcoexp[ch][bnd] + 3 * audblk->mstrcplco[ch]; + if(audblk->cplcoexp[ch][bnd] == 15) + cpl_mant_tmp = (audblk->cplcomant[ch][bnd]) << 11; + else + cpl_mant_tmp = ((0x10) | audblk->cplcomant[ch][bnd]) << 10; + + cpl_coord = convert_to_float(cpl_exp_tmp,cpl_mant_tmp) * 8.0f; + + //Invert the phase for the right channel if necessary + if(bsi->acmod == 0x2 && audblk->phsflginu && ch == 1 && audblk->phsflg[bnd]) + cpl_coord *= -1; + + bnd++; + } + + for(j=0;j < 12; j++) + { + //Get new dither values for each channel if necessary, so + //the channels are uncorrelated + if(audblk->dithflag[ch] && audblk->cpl_bap[i] == 0) + mantissa = dither_gen(); + else + mantissa = audblk->cplmant[i]; + + samples[i] = cpl_coord * convert_to_float(audblk->cpl_exp[i],mantissa); + + i++; + } + } +} -- cgit v1.2.3