ref: 3254623f0745837118e0d5d739fa6c402fd5b9d3
dir: /libfaad/specrec.c/
/*
** FAAD - Freeware Advanced Audio Decoder
** Copyright (C) 2002 M. Bakker
**
** This program 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 of the License, or
** (at your option) any later version.
**
** This program 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 this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** $Id: specrec.c,v 1.22 2003/06/23 15:21:20 menno Exp $
**/
/*
Spectral reconstruction:
- grouping/sectioning
- inverse quantization
- applying scalefactors
*/
#include "common.h"
#include "structs.h"
#include <string.h>
#include "specrec.h"
#include "syntax.h"
#include "iq_table.h"
#ifdef LD_DEC
static uint8_t num_swb_512_window[] =
{
0, 0, 0, 36, 36, 37, 31, 31, 0, 0, 0, 0
};
static uint8_t num_swb_480_window[] =
{
0, 0, 0, 35, 35, 37, 30, 30, 0, 0, 0, 0
};
#endif
static uint8_t num_swb_960_window[] =
{
40, 40, 45, 49, 49, 49, 46, 46, 42, 42, 42, 40
};
static uint8_t num_swb_1024_window[] =
{
41, 41, 47, 49, 49, 51, 47, 47, 43, 43, 43, 40
};
static uint8_t num_swb_128_window[] =
{
12, 12, 12, 14, 14, 14, 15, 15, 15, 15, 15, 15
};
static uint16_t swb_offset_1024_96[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56,
64, 72, 80, 88, 96, 108, 120, 132, 144, 156, 172, 188, 212, 240,
276, 320, 384, 448, 512, 576, 640, 704, 768, 832, 896, 960, 1024
};
static uint16_t swb_offset_128_96[] =
{
0, 4, 8, 12, 16, 20, 24, 32, 40, 48, 64, 92, 128
};
static uint16_t swb_offset_1024_64[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56,
64, 72, 80, 88, 100, 112, 124, 140, 156, 172, 192, 216, 240, 268,
304, 344, 384, 424, 464, 504, 544, 584, 624, 664, 704, 744, 784, 824,
864, 904, 944, 984, 1024
};
static uint16_t swb_offset_128_64[] =
{
0, 4, 8, 12, 16, 20, 24, 32, 40, 48, 64, 92, 128
};
static uint16_t swb_offset_1024_48[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 48, 56, 64, 72,
80, 88, 96, 108, 120, 132, 144, 160, 176, 196, 216, 240, 264, 292,
320, 352, 384, 416, 448, 480, 512, 544, 576, 608, 640, 672, 704, 736,
768, 800, 832, 864, 896, 928, 1024
};
#ifdef LD_DEC
static uint16_t swb_offset_512_48[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 68, 76, 84,
92, 100, 112, 124, 136, 148, 164, 184, 208, 236, 268, 300, 332, 364, 396,
428, 460, 512
};
static uint16_t swb_offset_480_48[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 64, 72 ,80 ,88,
96, 108, 120, 132, 144, 156, 172, 188, 212, 240, 272, 304, 336, 368, 400,
432, 480
};
#endif
static uint16_t swb_offset_128_48[] =
{
0, 4, 8, 12, 16, 20, 28, 36, 44, 56, 68, 80, 96, 112, 128
};
static uint16_t swb_offset_1024_32[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 48, 56, 64, 72,
80, 88, 96, 108, 120, 132, 144, 160, 176, 196, 216, 240, 264, 292,
320, 352, 384, 416, 448, 480, 512, 544, 576, 608, 640, 672, 704, 736,
768, 800, 832, 864, 896, 928, 960, 992, 1024
};
#ifdef LD_DEC
static uint16_t swb_offset_512_32[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 64, 72, 80,
88, 96, 108, 120, 132, 144, 160, 176, 192, 212, 236, 260, 288, 320, 352,
384, 416, 448, 480, 512
};
static uint16_t swb_offset_480_32[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 72, 80,
88, 96, 104, 112, 124, 136, 148, 164, 180, 200, 224, 256, 288, 320, 352,
384, 416, 448, 480
};
#endif
static uint16_t swb_offset_1024_24[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 52, 60, 68,
76, 84, 92, 100, 108, 116, 124, 136, 148, 160, 172, 188, 204, 220,
240, 260, 284, 308, 336, 364, 396, 432, 468, 508, 552, 600, 652, 704,
768, 832, 896, 960, 1024
};
#ifdef LD_DEC
static uint16_t swb_offset_512_24[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 52, 60, 68,
80, 92, 104, 120, 140, 164, 192, 224, 256, 288, 320, 352, 384, 416,
448, 480, 512
};
static uint16_t swb_offset_480_24[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 52, 60, 68, 80, 92, 104, 120,
140, 164, 192, 224, 256, 288, 320, 352, 384, 416, 448, 480
};
#endif
static uint16_t swb_offset_128_24[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 36, 44, 52, 64, 76, 92, 108, 128
};
static uint16_t swb_offset_1024_16[] =
{
0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 100, 112, 124,
136, 148, 160, 172, 184, 196, 212, 228, 244, 260, 280, 300, 320, 344,
368, 396, 424, 456, 492, 532, 572, 616, 664, 716, 772, 832, 896, 960, 1024
};
static uint16_t swb_offset_128_16[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 32, 40, 48, 60, 72, 88, 108, 128
};
static uint16_t swb_offset_1024_8[] =
{
0, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 172,
188, 204, 220, 236, 252, 268, 288, 308, 328, 348, 372, 396, 420, 448,
476, 508, 544, 580, 620, 664, 712, 764, 820, 880, 944, 1024
};
static uint16_t swb_offset_128_8[] =
{
0, 4, 8, 12, 16, 20, 24, 28, 36, 44, 52, 60, 72, 88, 108, 128
};
static uint16_t *swb_offset_1024_window[] =
{
swb_offset_1024_96, /* 96000 */
swb_offset_1024_96, /* 88200 */
swb_offset_1024_64, /* 64000 */
swb_offset_1024_48, /* 48000 */
swb_offset_1024_48, /* 44100 */
swb_offset_1024_32, /* 32000 */
swb_offset_1024_24, /* 24000 */
swb_offset_1024_24, /* 22050 */
swb_offset_1024_16, /* 16000 */
swb_offset_1024_16, /* 12000 */
swb_offset_1024_16, /* 11025 */
swb_offset_1024_8 /* 8000 */
};
#ifdef LD_DEC
static uint16_t *swb_offset_512_window[] =
{
0, /* 96000 */
0, /* 88200 */
0, /* 64000 */
swb_offset_512_48, /* 48000 */
swb_offset_512_48, /* 44100 */
swb_offset_512_32, /* 32000 */
swb_offset_512_24, /* 24000 */
swb_offset_512_24, /* 22050 */
0, /* 16000 */
0, /* 12000 */
0, /* 11025 */
0 /* 8000 */
};
static uint16_t *swb_offset_480_window[] =
{
0, /* 96000 */
0, /* 88200 */
0, /* 64000 */
swb_offset_480_48, /* 48000 */
swb_offset_480_48, /* 44100 */
swb_offset_480_32, /* 32000 */
swb_offset_480_24, /* 24000 */
swb_offset_480_24, /* 22050 */
0, /* 16000 */
0, /* 12000 */
0, /* 11025 */
0 /* 8000 */
};
#endif
static uint16_t *swb_offset_128_window[] =
{
swb_offset_128_96, /* 96000 */
swb_offset_128_96, /* 88200 */
swb_offset_128_64, /* 64000 */
swb_offset_128_48, /* 48000 */
swb_offset_128_48, /* 44100 */
swb_offset_128_48, /* 32000 */
swb_offset_128_24, /* 24000 */
swb_offset_128_24, /* 22050 */
swb_offset_128_16, /* 16000 */
swb_offset_128_16, /* 12000 */
swb_offset_128_16, /* 11025 */
swb_offset_128_8 /* 8000 */
};
#define bit_set(A, B) ((A) & (1<<(B)))
/* 4.5.2.3.4 */
/*
- determine the number of windows in a window_sequence named num_windows
- determine the number of window_groups named num_window_groups
- determine the number of windows in each group named window_group_length[g]
- determine the total number of scalefactor window bands named num_swb for
the actual window type
- determine swb_offset[swb], the offset of the first coefficient in
scalefactor window band named swb of the window actually used
- determine sect_sfb_offset[g][section],the offset of the first coefficient
in section named section. This offset depends on window_sequence and
scale_factor_grouping and is needed to decode the spectral_data().
*/
uint8_t window_grouping_info(faacDecHandle hDecoder, ic_stream *ics)
{
uint8_t i, g;
uint8_t sf_index = hDecoder->sf_index;
switch (ics->window_sequence) {
case ONLY_LONG_SEQUENCE:
case LONG_START_SEQUENCE:
case LONG_STOP_SEQUENCE:
ics->num_windows = 1;
ics->num_window_groups = 1;
ics->window_group_length[ics->num_window_groups-1] = 1;
#ifdef LD_DEC
if (hDecoder->object_type == LD)
{
if (hDecoder->frameLength == 512)
ics->num_swb = num_swb_512_window[sf_index];
else /* if (hDecoder->frameLength == 480) */
ics->num_swb = num_swb_480_window[sf_index];
} else {
#endif
if (hDecoder->frameLength == 1024)
ics->num_swb = num_swb_1024_window[sf_index];
else /* if (hDecoder->frameLength == 960) */
ics->num_swb = num_swb_960_window[sf_index];
#ifdef LD_DEC
}
#endif
/* preparation of sect_sfb_offset for long blocks */
/* also copy the last value! */
#ifdef LD_DEC
if (hDecoder->object_type == LD)
{
if (hDecoder->frameLength == 512)
{
for (i = 0; i < ics->num_swb; i++)
{
ics->sect_sfb_offset[0][i] = swb_offset_512_window[sf_index][i];
ics->swb_offset[i] = swb_offset_512_window[sf_index][i];
}
} else /* if (hDecoder->frameLength == 480) */ {
for (i = 0; i < ics->num_swb; i++)
{
ics->sect_sfb_offset[0][i] = swb_offset_480_window[sf_index][i];
ics->swb_offset[i] = swb_offset_480_window[sf_index][i];
}
}
ics->sect_sfb_offset[0][ics->num_swb] = hDecoder->frameLength;
ics->swb_offset[ics->num_swb] = hDecoder->frameLength;
} else {
#endif
for (i = 0; i < ics->num_swb; i++)
{
ics->sect_sfb_offset[0][i] = swb_offset_1024_window[sf_index][i];
ics->swb_offset[i] = swb_offset_1024_window[sf_index][i];
}
ics->sect_sfb_offset[0][ics->num_swb] = hDecoder->frameLength;
ics->swb_offset[ics->num_swb] = hDecoder->frameLength;
#ifdef LD_DEC
}
#endif
return 0;
case EIGHT_SHORT_SEQUENCE:
ics->num_windows = 8;
ics->num_window_groups = 1;
ics->window_group_length[ics->num_window_groups-1] = 1;
ics->num_swb = num_swb_128_window[sf_index];
for (i = 0; i < ics->num_swb; i++)
ics->swb_offset[i] = swb_offset_128_window[sf_index][i];
ics->swb_offset[ics->num_swb] = hDecoder->frameLength/8;
for (i = 0; i < ics->num_windows-1; i++) {
if (bit_set(ics->scale_factor_grouping, 6-i) == 0)
{
ics->num_window_groups += 1;
ics->window_group_length[ics->num_window_groups-1] = 1;
} else {
ics->window_group_length[ics->num_window_groups-1] += 1;
}
}
/* preparation of sect_sfb_offset for short blocks */
for (g = 0; g < ics->num_window_groups; g++)
{
uint16_t width;
uint8_t sect_sfb = 0;
uint16_t offset = 0;
for (i = 0; i < ics->num_swb; i++)
{
if (i+1 == ics->num_swb)
{
width = (hDecoder->frameLength/8) - swb_offset_128_window[sf_index][i];
} else {
width = swb_offset_128_window[sf_index][i+1] -
swb_offset_128_window[sf_index][i];
}
width *= ics->window_group_length[g];
ics->sect_sfb_offset[g][sect_sfb++] = offset;
offset += width;
}
ics->sect_sfb_offset[g][sect_sfb] = offset;
}
return 0;
default:
return 1;
}
}
/*
For ONLY_LONG_SEQUENCE windows (num_window_groups = 1,
window_group_length[0] = 1) the spectral data is in ascending spectral
order.
For the EIGHT_SHORT_SEQUENCE window, the spectral order depends on the
grouping in the following manner:
- Groups are ordered sequentially
- Within a group, a scalefactor band consists of the spectral data of all
grouped SHORT_WINDOWs for the associated scalefactor window band. To
clarify via example, the length of a group is in the range of one to eight
SHORT_WINDOWs.
- If there are eight groups each with length one (num_window_groups = 8,
window_group_length[0..7] = 1), the result is a sequence of eight spectra,
each in ascending spectral order.
- If there is only one group with length eight (num_window_groups = 1,
window_group_length[0] = 8), the result is that spectral data of all eight
SHORT_WINDOWs is interleaved by scalefactor window bands.
- Within a scalefactor window band, the coefficients are in ascending
spectral order.
*/
void quant_to_spec(ic_stream *ics, real_t *spec_data, uint16_t frame_len)
{
uint8_t g, sfb, win;
uint16_t width, bin;
real_t *start_inptr, *start_win_ptr, *win_ptr;
real_t tmp_spec[1024];
real_t *tmp_spec_ptr, *spec_ptr;
tmp_spec_ptr = tmp_spec;
memset(tmp_spec_ptr, 0, frame_len*sizeof(real_t));
spec_ptr = spec_data;
tmp_spec_ptr = tmp_spec;
start_win_ptr = tmp_spec_ptr;
for (g = 0; g < ics->num_window_groups; g++)
{
uint16_t j = 0;
uint16_t win_inc = 0;
start_inptr = spec_ptr;
win_inc = ics->swb_offset[ics->num_swb];
for (sfb = 0; sfb < ics->num_swb; sfb++)
{
width = ics->swb_offset[sfb+1] - ics->swb_offset[sfb];
win_ptr = start_win_ptr;
for (win = 0; win < ics->window_group_length[g]; win++)
{
tmp_spec_ptr = win_ptr + j;
for (bin = 0; bin < width; bin += 4)
{
tmp_spec_ptr[0] = spec_ptr[0];
tmp_spec_ptr[1] = spec_ptr[1];
tmp_spec_ptr[2] = spec_ptr[2];
tmp_spec_ptr[3] = spec_ptr[3];
tmp_spec_ptr += 4;
spec_ptr += 4;
}
win_ptr += win_inc;
}
j += width;
}
start_win_ptr += (spec_ptr - start_inptr);
}
spec_ptr = spec_data;
tmp_spec_ptr = tmp_spec;
memcpy(spec_ptr, tmp_spec_ptr, frame_len*sizeof(real_t));
}
#ifndef FIXED_POINT
void build_tables(real_t *pow2_table)
{
uint16_t i;
/* build pow(2, 0.25*x) table for scalefactors */
for(i = 0; i < POW_TABLE_SIZE; i++)
{
pow2_table[i] = REAL_CONST(pow(2.0, 0.25 * (i-100)));
}
}
#endif
static INLINE real_t iquant(int16_t q, real_t *tab)
{
int16_t sgn = 1;
if (q == 0) return 0;
if (q < 0)
{
q = -q;
sgn = -1;
}
if (q >= IQ_TABLE_SIZE)
return sgn * tab[q>>3] * 16;
return sgn * tab[q];
}
void inverse_quantization(real_t *x_invquant, int16_t *x_quant, uint16_t frame_len)
{
int16_t i;
int16_t *in_ptr = x_quant;
real_t *out_ptr = x_invquant;
real_t *tab = iq_table;
for(i = frame_len/4-1; i >= 0; --i)
{
out_ptr[0] = iquant(in_ptr[0], tab);
out_ptr[1] = iquant(in_ptr[1], tab);
out_ptr[2] = iquant(in_ptr[2], tab);
out_ptr[3] = iquant(in_ptr[3], tab);
out_ptr += 4;
in_ptr += 4;
}
}
#ifndef FIXED_POINT
static INLINE real_t get_scale_factor_gain(uint16_t scale_factor, real_t *pow2_table)
{
if (scale_factor < POW_TABLE_SIZE)
return pow2_table[scale_factor];
else
return REAL_CONST(pow(2.0, 0.25 * (scale_factor - 100)));
}
#else
static real_t pow2_table[] =
{
COEF_CONST(0.59460355750136),
COEF_CONST(0.70710678118655),
COEF_CONST(0.84089641525371),
COEF_CONST(1.0),
COEF_CONST(1.18920711500272),
COEF_CONST(1.41421356237310),
COEF_CONST(1.68179283050743)
};
#endif
#ifdef FIXED_POINT
void apply_scalefactors(faacDecHandle hDecoder, ic_stream *ics, real_t *x_invquant,
uint16_t frame_len)
#else
void apply_scalefactors(ic_stream *ics, real_t *x_invquant, real_t *pow2_table,
uint16_t frame_len)
#endif
{
uint8_t g, sfb;
uint16_t top;
real_t *fp;
#ifndef FIXED_POINT
real_t scale;
#else
int32_t exp, frac;
#endif
uint8_t groups = 0;
uint16_t nshort = frame_len/8;
for (g = 0; g < ics->num_window_groups; g++)
{
uint16_t k = 0;
/* using this 128*groups doesn't hurt long blocks, because
long blocks only have 1 group, so that means 'groups' is
always 0 for long blocks
*/
fp = x_invquant + (groups*nshort);
for (sfb = 0; sfb < ics->max_sfb; sfb++)
{
top = ics->sect_sfb_offset[g][sfb+1];
#ifndef FIXED_POINT
scale = get_scale_factor_gain(ics->scale_factors[g][sfb], pow2_table);
#else
exp = (ics->scale_factors[g][sfb] - 100) / 4;
frac = (ics->scale_factors[g][sfb] - 100) % 4;
if (hDecoder->object_type == LD)
{
exp -= 6 /*9*/;
} else {
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
exp -= 4 /*7*/;
else
exp -= 7 /*10*/;
}
#endif
/* minimum size of a sf band is 4 and always a multiple of 4 */
for ( ; k < top; k += 4)
{
#ifndef FIXED_POINT
fp[0] = fp[0] * scale;
fp[1] = fp[1] * scale;
fp[2] = fp[2] * scale;
fp[3] = fp[3] * scale;
#else
if (exp < 0)
{
fp[0] >>= -exp;
fp[1] >>= -exp;
fp[2] >>= -exp;
fp[3] >>= -exp;
} else {
fp[0] <<= exp;
fp[1] <<= exp;
fp[2] <<= exp;
fp[3] <<= exp;
}
if (frac)
{
fp[0] = MUL_R_C(fp[0],pow2_table[frac + 3]);
fp[1] = MUL_R_C(fp[1],pow2_table[frac + 3]);
fp[2] = MUL_R_C(fp[2],pow2_table[frac + 3]);
fp[3] = MUL_R_C(fp[3],pow2_table[frac + 3]);
}
#endif
fp += 4;
}
}
groups += ics->window_group_length[g];
}
}