vdr/ac3dec/coeff.c

/* 
 *    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 <stdlib.h>
#include <stdio.h>
#include "ac3.h"
#include "ac3_internal.h"


#include "bitstream.h"
#include "dither.h"
#include "coeff.h"


//
//Lookup tables of 0.15 two's complement quantization values
//
#define Q0 ((-2 << 15) / 3.0)
#define Q1 (0)
#define Q2 ((2 << 15) / 3.0)

static const float q_1_0[ 32 ] =
{
	Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,
	Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,
	Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,
	0,0,0,0,0
};                                                                              

static const float q_1_1[ 32 ] =
{
	Q0,Q0,Q0,Q1,Q1,Q1,Q2,Q2,Q2,
	Q0,Q0,Q0,Q1,Q1,Q1,Q2,Q2,Q2,
	Q0,Q0,Q0,Q1,Q1,Q1,Q2,Q2,Q2,
	0,0,0,0,0
};                                                                              

static const float q_1_2[ 32 ] =
{
	Q0,Q1,Q2,Q0,Q1,Q2,Q0,Q1,Q2,
	Q0,Q1,Q2,Q0,Q1,Q2,Q0,Q1,Q2,
	Q0,Q1,Q2,Q0,Q1,Q2,Q0,Q1,Q2,
	0,0,0,0,0
};                                                                              

#undef Q0
#undef Q1
#undef Q2

#define Q0 ((-4 << 15) / 5.0)
#define Q1 ((-2 << 15) / 5.0)
#define Q2 (0)
#define Q3 ((2 << 15) / 5.0)
#define Q4 ((4 << 15) / 5.0)

static const float q_2_0[ 128 ] =
{
	Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,
	Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,Q0,
	Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,
	Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,Q1,
	Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,
	Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,Q2,
	Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,
	Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,Q3,
	Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,
	Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,Q4,
	0,0,0
};                                                                              

static const float q_2_1[ 128 ] =
{
	Q0,Q0,Q0,Q0,Q0,Q1,Q1,Q1,Q1,Q1,
	Q2,Q2,Q2,Q2,Q2,Q3,Q3,Q3,Q3,Q3,
	Q4,Q4,Q4,Q4,Q4,Q0,Q0,Q0,Q0,Q0,
	Q1,Q1,Q1,Q1,Q1,Q2,Q2,Q2,Q2,Q2,
	Q3,Q3,Q3,Q3,Q3,Q4,Q4,Q4,Q4,Q4,
	Q0,Q0,Q0,Q0,Q0,Q1,Q1,Q1,Q1,Q1,
	Q2,Q2,Q2,Q2,Q2,Q3,Q3,Q3,Q3,Q3,
	Q4,Q4,Q4,Q4,Q4,Q0,Q0,Q0,Q0,Q0,
	Q1,Q1,Q1,Q1,Q1,Q2,Q2,Q2,Q2,Q2,
	Q3,Q3,Q3,Q3,Q3,Q4,Q4,Q4,Q4,Q4,
	Q0,Q0,Q0,Q0,Q0,Q1,Q1,Q1,Q1,Q1,
	Q2,Q2,Q2,Q2,Q2,Q3,Q3,Q3,Q3,Q3,
	Q4,Q4,Q4,Q4,Q4,0,0,0
 };

static const float q_2_2[ 128 ] =
 {
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,Q0,Q1,Q2,Q3,Q4,
	Q0,Q1,Q2,Q3,Q4,0,0,0
};                                                                              

#undef Q0
#undef Q1
#undef Q2
#undef Q3
#undef Q4                                                                      

static const float q_3[7] =
{
	(-6 << 15)/7.0, (-4 << 15)/7.0, (-2 << 15)/7.0, 0.0,
	( 2 << 15)/7.0, ( 4 << 15)/7.0, ( 6 << 15)/7.0
};

#define Q0 ((-10 << 15) / 11.0)
#define Q1 ((-8 << 15) / 11.0)
#define Q2 ((-6 << 15) / 11.0)
#define Q3 ((-4 << 15) / 11.0)
#define Q4 ((-2 << 15) / 11.0)
#define Q5 (0)
#define Q6 ((2 << 15) / 11.0)
#define Q7 ((4 << 15) / 11.0)
#define Q8 ((6 << 15) / 11.0)
#define Q9 ((8 << 15) / 11.0)
#define QA ((10 << 15) / 11.0)

static const float q_4_0[ 128 ] =
{
	Q0, Q0, Q0, Q0, Q0, Q0, Q0, Q0, Q0, Q0, Q0,
	Q1, Q1, Q1, Q1, Q1, Q1, Q1, Q1, Q1, Q1, Q1,
	Q2, Q2, Q2, Q2, Q2, Q2, Q2, Q2, Q2, Q2, Q2,
	Q3, Q3, Q3, Q3, Q3, Q3, Q3, Q3, Q3, Q3, Q3,
	Q4, Q4, Q4, Q4, Q4, Q4, Q4, Q4, Q4, Q4, Q4,
	Q5, Q5, Q5, Q5, Q5, Q5, Q5, Q5, Q5, Q5, Q5,
	Q6, Q6, Q6, Q6, Q6, Q6, Q6, Q6, Q6, Q6, Q6,
	Q7, Q7, Q7, Q7, Q7, Q7, Q7, Q7, Q7, Q7, Q7,
	Q8, Q8, Q8, Q8, Q8, Q8, Q8, Q8, Q8, Q8, Q8,
	Q9, Q9, Q9, Q9, Q9, Q9, Q9, Q9, Q9, Q9, Q9,
	QA, QA, QA, QA, QA, QA, QA, QA, QA, QA, QA,
	 0,  0,  0,  0,  0,  0,  0
 };

static const float q_4_1[ 128 ] =
{
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, QA,
	 0,  0,  0,  0,  0,  0,  0
};

#undef Q0
#undef Q1
#undef Q2
#undef Q3
#undef Q4
#undef Q5
#undef Q6
#undef Q7
#undef Q8
#undef Q9
#undef QA                                                                       

static const float q_5[15] =
{
	(-14 << 15)/15.0,(-12 << 15)/15.0,(-10 << 15)/15.0,
	( -8 << 15)/15.0,( -6 << 15)/15.0,( -4 << 15)/15.0,
	( -2 << 15)/15.0,   0.0          ,(  2 << 15)/15.0,
	(  4 << 15)/15.0,(  6 << 15)/15.0,(  8 << 15)/15.0,
	( 10 << 15)/15.0,( 12 << 15)/15.0,( 14 << 15)/15.0
};                                                                              

//
// Scale factors for convert_to_float
//

static const uint32_t 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 float q_1[2];
static float q_2[2];
static float q_4[1];
static int32_t q_1_pointer;
static int32_t q_2_pointer;
static int32_t q_4_pointer;
static float __inline__
coeff_get_float(uint16_t bap, uint16_t dithflag, uint16_t exp);

//Conversion from bap to number of bits in the mantissas
//zeros account for cases 0,1,2,4 which are special cased
static uint16_t qnttztab[16] =
{
	 0,  0,  0,  3,
	 0,  4,  5,  6,
	 7,  8,  9, 10,
	11, 12, 14, 16
};

static void	coeff_reset(void);
static float	coeff_get_float(uint16_t bap, uint16_t dithflag, uint16_t exp);
static void	coeff_uncouple_ch(float samples[],bsi_t *bsi,audblk_t *audblk,uint32_t ch);

void coeff_unpack(bsi_t *bsi, audblk_t *audblk, stream_samples_t samples)
{
	uint16_t i,j;
	uint32_t done_cpl = 0;

	coeff_reset();

	for(i=0; i< bsi->nfchans; i++) {
		for(j=0; j < audblk->endmant[i]; j++)
			samples[i][j] = coeff_get_float(audblk->fbw_bap[i][j], audblk->dithflag[i], audblk->fbw_exp[i][j]);

		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->cpl_flt[j] = coeff_get_float(audblk->cpl_bap[j],0, audblk->cpl_exp[j]);
			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++)
			samples[5][j] = coeff_get_float(audblk->lfe_bap[j], 0, audblk->lfe_exp[j]);
	}
}


/**
 * Fetch a float from the bitstream
 **/

static float inline coeff_get_float (uint16_t bap, uint16_t dithflag, uint16_t exp)
{
	uint16_t dummy = 0;

	//If the bap is 0-5 then we have special cases to take care of
	switch(bap) {
		case 0:
			if(dithflag)
				return (dither_gen() * scale_factor[exp]);

			return 0.0;

		case 1:
			if (q_1_pointer >= 0)
				return(q_1[q_1_pointer--] * scale_factor[exp]);

			if ((dummy = bitstream_get (5)) > 26)
				goto error;

			q_1[1] = q_1_1[dummy];
			q_1[0] = q_1_2[dummy];
			q_1_pointer = 1;

			return (q_1_0[dummy] * scale_factor[exp]);

		case 2:
			if(q_2_pointer >= 0)
				return (q_2[q_2_pointer--] * scale_factor[exp]);

			if ((dummy = bitstream_get (7)) > 124)
				goto error;

			q_2[1] = q_2_1[dummy];
			q_2[0] = q_2_2[dummy];
			q_2_pointer = 1;

			return (q_2_0[dummy] * scale_factor[exp]);

		case 3:
			if ((dummy = bitstream_get (3)) > 6)
				goto error;

			return (q_3[dummy] * scale_factor[exp]);

		case 4:
			if(q_4_pointer >= 0)
				return (q_4[q_4_pointer--] * scale_factor[exp]);

			if ((dummy = bitstream_get (7)) > 120)
				goto error;

			q_4[0] = q_4_1[dummy];
			q_4_pointer = 0;

			return (q_4_0[dummy] * scale_factor[exp]);  

		case 5:
			if ((dummy = bitstream_get (4)) > 14)
				goto error;

			return (q_5[dummy] * scale_factor[exp]);

		default:
			dummy = bitstream_get(qnttztab[bap]);
			dummy <<= 16 - qnttztab[bap];
			return ((int16_t)dummy * scale_factor[exp]);  
	}

error:
#ifdef DEBUG
	fprintf(stderr,"** Invalid mantissa - skipping frame **\n");
#endif
	HANDLE_ERROR();
}


/**
 * Reset the mantissa state
 **/

static void coeff_reset(void)
{
	q_1_pointer = q_2_pointer = q_4_pointer = -1;
}


/**
 * Uncouple the coupling channel into a fbw channel
 **/

static void coeff_uncouple_ch (float samples[],bsi_t *bsi,audblk_t *audblk,uint32_t ch)
{
	uint32_t bnd = 0;
	uint32_t sub_bnd = 0;
	uint32_t i,j;
	float cpl_coord = 1.0;
	uint32_t cpl_exp_tmp;
	uint32_t cpl_mant_tmp;

	for (i=audblk->cplstrtmant;i<audblk->cplendmant;) {
		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 = (cpl_mant_tmp * scale_factor[cpl_exp_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])
				samples[i] = cpl_coord * (dither_gen() * scale_factor[audblk->cpl_exp[i]]);
			else
				samples[i] = cpl_coord * audblk->cpl_flt[i];

			i++;
		}
	}
}