ref: a2c4357825c73ef93133df2152be0d6bb6ad8343
dir: /libfaad/rvlc.c/
/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
**
** 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.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** The "appropriate copyright message" mentioned in section 2c of the GPLv2
** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
**
** $Id: rvlc.c,v 1.21 2007/11/01 12:33:34 menno Exp $
**/
/* RVLC scalefactor decoding
*
* RVLC works like this:
* 1. Only symmetric huffman codewords are used
* 2. Total length of the scalefactor data is stored in the bitsream
* 3. Scalefactors are DPCM coded
* 4. Next to the starting value for DPCM the ending value is also stored
*
* With all this it is possible to read the scalefactor data from 2 sides.
* If there is a bit error in the scalefactor data it is possible to start
* decoding from the other end of the data, to find all but 1 scalefactor.
*/
#include "common.h"
#include "structs.h"
#include <stdlib.h>
#include "syntax.h"
#include "bits.h"
#include "rvlc.h"
#ifdef ERROR_RESILIENCE
//#define PRINT_RVLC
/* static function declarations */
static uint8_t rvlc_decode_sf_forward(ic_stream *ics,
bitfile *ld_sf,
bitfile *ld_esc,
uint8_t *is_used);
#if 0
static uint8_t rvlc_decode_sf_reverse(ic_stream *ics,
bitfile *ld_sf,
bitfile *ld_esc,
uint8_t is_used);
#endif
static int8_t rvlc_huffman_sf(bitfile *ld_sf, bitfile *ld_esc,
int8_t direction);
static int8_t rvlc_huffman_esc(bitfile *ld_esc, int8_t direction);
uint8_t rvlc_scale_factor_data(ic_stream *ics, bitfile *ld)
{
uint8_t bits = 9;
ics->sf_concealment = faad_get1bit(ld
DEBUGVAR(1,149,"rvlc_scale_factor_data(): sf_concealment"));
ics->rev_global_gain = (uint8_t)faad_getbits(ld, 8
DEBUGVAR(1,150,"rvlc_scale_factor_data(): rev_global_gain"));
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
bits = 11;
/* the number of bits used for the huffman codewords */
ics->length_of_rvlc_sf = (uint16_t)faad_getbits(ld, bits
DEBUGVAR(1,151,"rvlc_scale_factor_data(): length_of_rvlc_sf"));
if (ics->noise_used)
{
ics->dpcm_noise_nrg = (uint16_t)faad_getbits(ld, 9
DEBUGVAR(1,152,"rvlc_scale_factor_data(): dpcm_noise_nrg"));
ics->length_of_rvlc_sf -= 9;
}
ics->sf_escapes_present = faad_get1bit(ld
DEBUGVAR(1,153,"rvlc_scale_factor_data(): sf_escapes_present"));
if (ics->sf_escapes_present)
{
ics->length_of_rvlc_escapes = (uint8_t)faad_getbits(ld, 8
DEBUGVAR(1,154,"rvlc_scale_factor_data(): length_of_rvlc_escapes"));
}
if (ics->noise_used)
{
ics->dpcm_noise_last_position = (uint16_t)faad_getbits(ld, 9
DEBUGVAR(1,155,"rvlc_scale_factor_data(): dpcm_noise_last_position"));
}
return 0;
}
uint8_t rvlc_decode_scale_factors(ic_stream *ics, bitfile *ld)
{
uint8_t result;
uint8_t intensity_used = 0;
uint8_t *rvlc_sf_buffer = NULL;
uint8_t *rvlc_esc_buffer = NULL;
bitfile ld_rvlc_sf, ld_rvlc_esc;
// bitfile ld_rvlc_sf_rev, ld_rvlc_esc_rev;
if (ics->length_of_rvlc_sf > 0)
{
/* We read length_of_rvlc_sf bits here to put it in a
seperate bitfile.
*/
rvlc_sf_buffer = faad_getbitbuffer(ld, ics->length_of_rvlc_sf
DEBUGVAR(1,156,"rvlc_decode_scale_factors(): bitbuffer: length_of_rvlc_sf"));
faad_initbits(&ld_rvlc_sf, (void*)rvlc_sf_buffer, bit2byte(ics->length_of_rvlc_sf));
// faad_initbits_rev(&ld_rvlc_sf_rev, (void*)rvlc_sf_buffer,
// ics->length_of_rvlc_sf);
}
if (ics->sf_escapes_present)
{
/* We read length_of_rvlc_escapes bits here to put it in a
seperate bitfile.
*/
rvlc_esc_buffer = faad_getbitbuffer(ld, ics->length_of_rvlc_escapes
DEBUGVAR(1,157,"rvlc_decode_scale_factors(): bitbuffer: length_of_rvlc_escapes"));
faad_initbits(&ld_rvlc_esc, (void*)rvlc_esc_buffer, bit2byte(ics->length_of_rvlc_escapes));
// faad_initbits_rev(&ld_rvlc_esc_rev, (void*)rvlc_esc_buffer,
// ics->length_of_rvlc_escapes);
}
/* decode the rvlc scale factors and escapes */
result = rvlc_decode_sf_forward(ics, &ld_rvlc_sf,
&ld_rvlc_esc, &intensity_used);
// result = rvlc_decode_sf_reverse(ics, &ld_rvlc_sf_rev,
// &ld_rvlc_esc_rev, intensity_used);
if (rvlc_esc_buffer) faad_free(rvlc_esc_buffer);
if (rvlc_sf_buffer) faad_free(rvlc_sf_buffer);
if (ics->length_of_rvlc_sf > 0)
faad_endbits(&ld_rvlc_sf);
if (ics->sf_escapes_present)
faad_endbits(&ld_rvlc_esc);
return result;
}
static uint8_t rvlc_decode_sf_forward(ic_stream *ics, bitfile *ld_sf, bitfile *ld_esc,
uint8_t *intensity_used)
{
int8_t g, sfb;
int8_t t = 0;
int8_t error = 0;
int8_t noise_pcm_flag = 1;
int16_t scale_factor = ics->global_gain;
int16_t is_position = 0;
int16_t noise_energy = ics->global_gain - 90 - 256;
#ifdef PRINT_RVLC
printf("\nglobal_gain: %d\n", ics->global_gain);
#endif
for (g = 0; g < ics->num_window_groups; g++)
{
for (sfb = 0; sfb < ics->max_sfb; sfb++)
{
if (error)
{
ics->scale_factors[g][sfb] = 0;
} else {
switch (ics->sfb_cb[g][sfb])
{
case ZERO_HCB: /* zero book */
ics->scale_factors[g][sfb] = 0;
break;
case INTENSITY_HCB: /* intensity books */
case INTENSITY_HCB2:
*intensity_used = 1;
/* decode intensity position */
t = rvlc_huffman_sf(ld_sf, ld_esc, +1);
is_position += t;
ics->scale_factors[g][sfb] = is_position;
break;
case NOISE_HCB: /* noise books */
/* decode noise energy */
if (noise_pcm_flag)
{
int16_t n = ics->dpcm_noise_nrg;
noise_pcm_flag = 0;
noise_energy += n;
} else {
t = rvlc_huffman_sf(ld_sf, ld_esc, +1);
noise_energy += t;
}
ics->scale_factors[g][sfb] = noise_energy;
break;
default: /* spectral books */
/* decode scale factor */
t = rvlc_huffman_sf(ld_sf, ld_esc, +1);
scale_factor += t;
if (scale_factor < 0)
return 4;
ics->scale_factors[g][sfb] = scale_factor;
break;
}
#ifdef PRINT_RVLC
printf("%3d:%4d%4d\n", sfb, ics->sfb_cb[g][sfb],
ics->scale_factors[g][sfb]);
#endif
if (t == 99)
{
error = 1;
}
}
}
}
#ifdef PRINT_RVLC
printf("\n\n");
#endif
return 0;
}
#if 0 // not used right now, doesn't work correctly yet
static uint8_t rvlc_decode_sf_reverse(ic_stream *ics, bitfile *ld_sf, bitfile *ld_esc,
uint8_t intensity_used)
{
int8_t g, sfb;
int8_t t = 0;
int8_t error = 0;
int8_t noise_pcm_flag = 1, is_pcm_flag = 1, sf_pcm_flag = 1;
int16_t scale_factor = ics->rev_global_gain;
int16_t is_position = 0;
int16_t noise_energy = ics->rev_global_gain;
#ifdef PRINT_RVLC
printf("\nrev_global_gain: %d\n", ics->rev_global_gain);
#endif
if (intensity_used)
{
is_position = rvlc_huffman_sf(ld_sf, ld_esc, -1);
#ifdef PRINT_RVLC
printf("is_position: %d\n", is_position);
#endif
}
for (g = ics->num_window_groups-1; g >= 0; g--)
{
for (sfb = ics->max_sfb-1; sfb >= 0; sfb--)
{
if (error)
{
ics->scale_factors[g][sfb] = 0;
} else {
switch (ics->sfb_cb[g][sfb])
{
case ZERO_HCB: /* zero book */
ics->scale_factors[g][sfb] = 0;
break;
case INTENSITY_HCB: /* intensity books */
case INTENSITY_HCB2:
if (is_pcm_flag)
{
is_pcm_flag = 0;
ics->scale_factors[g][sfb] = is_position;
} else {
t = rvlc_huffman_sf(ld_sf, ld_esc, -1);
is_position -= t;
ics->scale_factors[g][sfb] = (uint8_t)is_position;
}
break;
case NOISE_HCB: /* noise books */
/* decode noise energy */
if (noise_pcm_flag)
{
noise_pcm_flag = 0;
noise_energy = ics->dpcm_noise_last_position;
} else {
t = rvlc_huffman_sf(ld_sf, ld_esc, -1);
noise_energy -= t;
}
ics->scale_factors[g][sfb] = (uint8_t)noise_energy;
break;
default: /* spectral books */
if (sf_pcm_flag || (sfb == 0))
{
sf_pcm_flag = 0;
if (sfb == 0)
scale_factor = ics->global_gain;
} else {
/* decode scale factor */
t = rvlc_huffman_sf(ld_sf, ld_esc, -1);
scale_factor -= t;
}
if (scale_factor < 0)
return 4;
ics->scale_factors[g][sfb] = (uint8_t)scale_factor;
break;
}
#ifdef PRINT_RVLC
printf("%3d:%4d%4d\n", sfb, ics->sfb_cb[g][sfb],
ics->scale_factors[g][sfb]);
#endif
if (t == 99)
{
error = 1;
}
}
}
}
#ifdef PRINT_RVLC
printf("\n\n");
#endif
return 0;
}
#endif
/* index == 99 means not allowed codeword */
static rvlc_huff_table book_rvlc[] = {
/*index length codeword */
{ 0, 1, 0 }, /* 0 */
{ -1, 3, 5 }, /* 101 */
{ 1, 3, 7 }, /* 111 */
{ -2, 4, 9 }, /* 1001 */
{ -3, 5, 17 }, /* 10001 */
{ 2, 5, 27 }, /* 11011 */
{ -4, 6, 33 }, /* 100001 */
{ 99, 6, 50 }, /* 110010 */
{ 3, 6, 51 }, /* 110011 */
{ 99, 6, 52 }, /* 110100 */
{ -7, 7, 65 }, /* 1000001 */
{ 99, 7, 96 }, /* 1100000 */
{ 99, 7, 98 }, /* 1100010 */
{ 7, 7, 99 }, /* 1100011 */
{ 4, 7, 107 }, /* 1101011 */
{ -5, 8, 129 }, /* 10000001 */
{ 99, 8, 194 }, /* 11000010 */
{ 5, 8, 195 }, /* 11000011 */
{ 99, 8, 212 }, /* 11010100 */
{ 99, 9, 256 }, /* 100000000 */
{ -6, 9, 257 }, /* 100000001 */
{ 99, 9, 426 }, /* 110101010 */
{ 6, 9, 427 }, /* 110101011 */
{ 99, 10, 0 } /* Shouldn't come this far */
};
static rvlc_huff_table book_escape[] = {
/*index length codeword */
{ 1, 2, 0 },
{ 0, 2, 2 },
{ 3, 3, 2 },
{ 2, 3, 6 },
{ 4, 4, 14 },
{ 7, 5, 13 },
{ 6, 5, 15 },
{ 5, 5, 31 },
{ 11, 6, 24 },
{ 10, 6, 25 },
{ 9, 6, 29 },
{ 8, 6, 61 },
{ 13, 7, 56 },
{ 12, 7, 120 },
{ 15, 8, 114 },
{ 14, 8, 242 },
{ 17, 9, 230 },
{ 16, 9, 486 },
{ 19, 10, 463 },
{ 18, 10, 974 },
{ 22, 11, 925 },
{ 20, 11, 1950 },
{ 21, 11, 1951 },
{ 23, 12, 1848 },
{ 25, 13, 3698 },
{ 24, 14, 7399 },
{ 26, 15, 14797 },
{ 49, 19, 236736 },
{ 50, 19, 236737 },
{ 51, 19, 236738 },
{ 52, 19, 236739 },
{ 53, 19, 236740 },
{ 27, 20, 473482 },
{ 28, 20, 473483 },
{ 29, 20, 473484 },
{ 30, 20, 473485 },
{ 31, 20, 473486 },
{ 32, 20, 473487 },
{ 33, 20, 473488 },
{ 34, 20, 473489 },
{ 35, 20, 473490 },
{ 36, 20, 473491 },
{ 37, 20, 473492 },
{ 38, 20, 473493 },
{ 39, 20, 473494 },
{ 40, 20, 473495 },
{ 41, 20, 473496 },
{ 42, 20, 473497 },
{ 43, 20, 473498 },
{ 44, 20, 473499 },
{ 45, 20, 473500 },
{ 46, 20, 473501 },
{ 47, 20, 473502 },
{ 48, 20, 473503 },
{ 99, 21, 0 } /* Shouldn't come this far */
};
static int8_t rvlc_huffman_sf(bitfile *ld_sf, bitfile *ld_esc,
int8_t direction)
{
uint8_t i, j;
int8_t index;
uint32_t cw;
rvlc_huff_table *h = book_rvlc;
i = h->len;
if (direction > 0)
cw = faad_getbits(ld_sf, i DEBUGVAR(1,0,""));
else
cw = faad_getbits_rev(ld_sf, i DEBUGVAR(1,0,""));
while ((cw != h->cw)
&& (i < 10))
{
h++;
j = h->len-i;
i += j;
cw <<= j;
if (direction > 0)
cw |= faad_getbits(ld_sf, j DEBUGVAR(1,0,""));
else
cw |= faad_getbits_rev(ld_sf, j DEBUGVAR(1,0,""));
}
index = h->index;
if (index == +ESC_VAL)
{
int8_t esc = rvlc_huffman_esc(ld_esc, direction);
if (esc == 99)
return 99;
index += esc;
#ifdef PRINT_RVLC
printf("esc: %d - ", esc);
#endif
}
if (index == -ESC_VAL)
{
int8_t esc = rvlc_huffman_esc(ld_esc, direction);
if (esc == 99)
return 99;
index -= esc;
#ifdef PRINT_RVLC
printf("esc: %d - ", esc);
#endif
}
return index;
}
static int8_t rvlc_huffman_esc(bitfile *ld,
int8_t direction)
{
uint8_t i, j;
uint32_t cw;
rvlc_huff_table *h = book_escape;
i = h->len;
if (direction > 0)
cw = faad_getbits(ld, i DEBUGVAR(1,0,""));
else
cw = faad_getbits_rev(ld, i DEBUGVAR(1,0,""));
while ((cw != h->cw)
&& (i < 21))
{
h++;
j = h->len-i;
i += j;
cw <<= j;
if (direction > 0)
cw |= faad_getbits(ld, j DEBUGVAR(1,0,""));
else
cw |= faad_getbits_rev(ld, j DEBUGVAR(1,0,""));
}
return h->index;
}
#endif