ref: e79f5009f833fbbe65b213c59e2e5c27e1ee1ce1
dir: /libfaad/syntax.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: syntax.c,v 1.12 2002/04/20 14:45:13 menno Exp $
**/
/*
Reads the AAC bitstream as defined in 14496-3 (MPEG-4 Audio)
(Note that there are some differences with 13818-7 (MPEG2), these
are also read correctly when the MPEG ID is known (can be found in
an ADTS header)).
*/
#include <stdlib.h>
#include <memory.h>
#include "common.h"
#include "syntax.h"
#include "specrec.h"
#include "huffman.h"
#include "bits.h"
#include "data.h"
#include "pulse.h"
#include "analysis.h"
#ifdef SBR
#include "sbr_syntax.h"
#endif
/* Table 4.4.1 */
uint8_t GASpecificConfig(bitfile *ld, uint8_t *channelConfiguration,
uint8_t object_type)
{
uint8_t frameLengthFlag, dependsOnCoreCoder, extensionFlag;
uint16_t coreCoderDelay;
program_config pce;
/* 1024 or 960 */
frameLengthFlag = faad_get1bit(ld
DEBUGVAR(1,138,"GASpecificConfig(): FrameLengthFlag"));
dependsOnCoreCoder = faad_get1bit(ld
DEBUGVAR(1,139,"GASpecificConfig(): DependsOnCoreCoder"));
if (dependsOnCoreCoder == 1)
{
coreCoderDelay = (uint16_t)faad_getbits(ld, 14
DEBUGVAR(1,140,"GASpecificConfig(): CoreCoderDelay"));
}
extensionFlag = faad_get1bit(ld DEBUGVAR(1,141,"GASpecificConfig(): ExtensionFlag"));
if (*channelConfiguration == 0)
{
program_config_element(&pce, ld);
*channelConfiguration = pce.channels;
if (pce.num_valid_cc_elements)
return -3;
}
if (extensionFlag == 1)
{
/* Error resilience not supported yet */
if (object_type == 23)
{
uint8_t tmp;
tmp = faad_get1bit(ld
DEBUGVAR(1,144,"GASpecificConfig(): aacSectionDataResilienceFlag"));
if (tmp)
return -6;
tmp = faad_get1bit(ld
DEBUGVAR(1,145,"GASpecificConfig(): aacScalefactorDataResilienceFlag"));
if (tmp)
return -6;
tmp = faad_get1bit(ld
DEBUGVAR(1,146,"GASpecificConfig(): aacSpectralDataResilienceFlag"));
if (tmp)
return -6;
/* 1 bit: extensionFlag3 */
}
}
return 0;
}
/* Table 4.4.2 */
/* An MPEG-4 Audio decoder is only required to follow the Program
Configuration Element in GASpecificConfig(). The decoder shall ignore
any Program Configuration Elements that may occur in raw data blocks.
PCEs transmitted in raw data blocks cannot be used to convey decoder
configuration information.
*/
uint8_t program_config_element(program_config *pce, bitfile *ld)
{
uint8_t i;
pce->channels = 0;
pce->element_instance_tag = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,10,"program_config_element(): element_instance_tag"));
pce->object_type = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,11,"program_config_element(): object_type"));
pce->sf_index = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,12,"program_config_element(): sf_index"));
pce->num_front_channel_elements = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,13,"program_config_element(): num_front_channel_elements"));
pce->num_side_channel_elements = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,14,"program_config_element(): num_side_channel_elements"));
pce->num_back_channel_elements = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,15,"program_config_element(): num_back_channel_elements"));
pce->num_lfe_channel_elements = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,16,"program_config_element(): num_lfe_channel_elements"));
pce->num_assoc_data_elements = (uint8_t)faad_getbits(ld, 3
DEBUGVAR(1,17,"program_config_element(): num_assoc_data_elements"));
pce->num_valid_cc_elements = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,18,"program_config_element(): num_valid_cc_elements"));
pce->mono_mixdown_present = faad_get1bit(ld
DEBUGVAR(1,19,"program_config_element(): mono_mixdown_present"));
if (pce->mono_mixdown_present == 1)
{
pce->mono_mixdown_element_number = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,20,"program_config_element(): mono_mixdown_element_number"));
}
pce->stereo_mixdown_present = faad_get1bit(ld
DEBUGVAR(1,21,"program_config_element(): stereo_mixdown_present"));
if (pce->stereo_mixdown_present == 1)
{
pce->stereo_mixdown_element_number = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,22,"program_config_element(): stereo_mixdown_element_number"));
}
pce->matrix_mixdown_idx_present = faad_get1bit(ld
DEBUGVAR(1,23,"program_config_element(): matrix_mixdown_idx_present"));
if (pce->matrix_mixdown_idx_present == 1)
{
pce->matrix_mixdown_idx = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,24,"program_config_element(): matrix_mixdown_idx"));
pce->pseudo_surround_enable = faad_get1bit(ld
DEBUGVAR(1,25,"program_config_element(): pseudo_surround_enable"));
}
for (i = 0; i < pce->num_front_channel_elements; i++)
{
if ((pce->front_element_is_cpe[i] = faad_get1bit(ld
DEBUGVAR(1,26,"program_config_element(): front_element_is_cpe"))) & 1)
{
pce->channels += 2;
} else {
pce->channels++;
}
pce->front_element_tag_select[i] = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,27,"program_config_element(): front_element_tag_select"));
}
for (i = 0; i < pce->num_side_channel_elements; i++)
{
if ((pce->side_element_is_cpe[i] = faad_get1bit(ld
DEBUGVAR(1,28,"program_config_element(): side_element_is_cpe"))) & 1)
{
pce->channels += 2;
} else {
pce->channels++;
}
pce->side_element_tag_select[i] = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,29,"program_config_element(): side_element_tag_select"));
}
for (i = 0; i < pce->num_back_channel_elements; i++)
{
if ((pce->back_element_is_cpe[i] = faad_get1bit(ld
DEBUGVAR(1,30,"program_config_element(): back_element_is_cpe"))) & 1)
{
pce->channels += 2;
} else {
pce->channels++;
}
pce->back_element_tag_select[i] = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,31,"program_config_element(): back_element_tag_select"));
}
for (i = 0; i < pce->num_lfe_channel_elements; i++)
{
pce->channels++;
pce->lfe_element_tag_select[i] = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,32,"program_config_element(): lfe_element_tag_select"));
}
for (i = 0; i < pce->num_assoc_data_elements; i++)
pce->assoc_data_element_tag_select[i] = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,33,"program_config_element(): assoc_data_element_tag_select"));
for (i = 0; i < pce->num_valid_cc_elements; i++)
{
/* have to count these as channels too?? (1 or 2) */
pce->channels += 2;
pce->cc_element_is_ind_sw[i] = faad_get1bit(ld
DEBUGVAR(1,34,"program_config_element(): cc_element_is_ind_sw"));
pce->valid_cc_element_tag_select[i] = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,35,"program_config_element(): valid_cc_element_tag_select"));
}
faad_byte_align(ld);
pce->comment_field_bytes = (uint8_t)faad_getbits(ld, 8
DEBUGVAR(1,36,"program_config_element(): comment_field_bytes"));
for (i = 0; i < pce->comment_field_bytes; i++)
{
pce->comment_field_data[i] = (uint8_t)faad_getbits(ld, 8
DEBUGVAR(1,37,"program_config_element(): comment_field_data"));
}
pce->comment_field_data[i] = 0;
return 0;
}
/* Table 4.4.4 and */
/* Table 4.4.9 */
uint8_t single_lfe_channel_element(element *sce, bitfile *ld, int16_t *spec_data,
uint8_t sf_index, uint8_t object_type)
{
ic_stream *ics = &(sce->ics1);
sce->element_instance_tag = (uint8_t)faad_getbits(ld, LEN_TAG
DEBUGVAR(1,38,"single_lfe_channel_element(): element_instance_tag"));
return individual_channel_stream(sce, ld, ics, 0, spec_data, sf_index,
object_type);
}
/* Table 4.4.5 */
uint8_t channel_pair_element(element *cpe, bitfile *ld, int16_t *spec_data1,
int16_t *spec_data2, uint8_t sf_index, uint8_t object_type)
{
uint8_t result;
ic_stream *ics1 = &(cpe->ics1);
ic_stream *ics2 = &(cpe->ics2);
cpe->element_instance_tag = (uint8_t)faad_getbits(ld, LEN_TAG
DEBUGVAR(1,39,"channel_pair_element(): element_instance_tag"));
if ((cpe->common_window = faad_get1bit(ld
DEBUGVAR(1,40,"channel_pair_element(): common_window"))) & 1)
{
/* both channels have common ics information */
if ((result = ics_info(ics1, ld, cpe->common_window, sf_index,
object_type)) > 0)
return result;
ics1->ms_mask_present = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,41,"channel_pair_element(): ms_mask_present"));
if (ics1->ms_mask_present == 1)
{
uint8_t g, sfb;
for (g = 0; g < ics1->num_window_groups; g++)
{
for (sfb = 0; sfb < ics1->max_sfb; sfb++)
{
ics1->ms_used[g][sfb] = faad_get1bit(ld
DEBUGVAR(1,42,"channel_pair_element(): faad_get1bit"));
}
}
}
memcpy(ics2, ics1, sizeof(ic_stream));
} else {
ics1->ms_mask_present = 0;
}
if ((result = individual_channel_stream(cpe, ld, ics1, 0, spec_data1,
sf_index, object_type)) > 0)
return result;
if ((result = individual_channel_stream(cpe, ld, ics2, 0, spec_data2,
sf_index, object_type)) > 0)
return result;
return 0;
}
/* Table 4.4.6 */
static uint8_t ics_info(ic_stream *ics, bitfile *ld, uint8_t common_window,
uint8_t sf_index, uint8_t object_type)
{
/* ics->ics_reserved_bit = */ faad_get1bit(ld
DEBUGVAR(1,43,"ics_info(): ics_reserved_bit"));
ics->window_sequence = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,44,"ics_info(): window_sequence"));
ics->window_shape = faad_get1bit(ld
DEBUGVAR(1,45,"ics_info(): window_shape"));
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
{
ics->max_sfb = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,46,"ics_info(): max_sfb (short)"));
ics->scale_factor_grouping = (uint8_t)faad_getbits(ld, 7
DEBUGVAR(1,47,"ics_info(): scale_factor_grouping"));
} else {
ics->max_sfb = (uint8_t)faad_getbits(ld, 6
DEBUGVAR(1,48,"ics_info(): max_sfb (long)"));
if ((ics->predictor_data_present = faad_get1bit(ld
DEBUGVAR(1,49,"ics_info(): predictor_data_present"))) & 1)
{
if (object_type == MAIN) /* MPEG2 style AAC predictor */
{
uint8_t sfb;
ics->pred.limit = min(ics->max_sfb, pred_sfb_max[sf_index]);
if ((ics->pred.predictor_reset = faad_get1bit(ld
DEBUGVAR(1,53,"ics_info(): pred.predictor_reset"))) & 1)
{
ics->pred.predictor_reset_group_number = (uint8_t)faad_getbits(ld, 5
DEBUGVAR(1,54,"ics_info(): pred.predictor_reset_group_number"));
}
for (sfb = 0; sfb < ics->pred.limit; sfb++)
{
ics->pred.prediction_used[sfb] = faad_get1bit(ld
DEBUGVAR(1,55,"ics_info(): pred.prediction_used"));
}
}
#ifdef LTP_DEC
else { /* Long Term Prediction */
if ((ics->ltp.data_present = faad_get1bit(ld
DEBUGVAR(1,50,"ics_info(): ltp.data_present"))) & 1)
{
ltp_data(ics, &(ics->ltp), ld, object_type);
}
if (common_window)
{
if ((ics->ltp2.data_present = faad_get1bit(ld
DEBUGVAR(1,51,"ics_info(): ltp2.data_present"))) & 1)
{
ltp_data(ics, &(ics->ltp2), ld, object_type);
}
}
}
#endif
}
}
/* get the grouping information */
return window_grouping_info(ics, sf_index, object_type);
}
/* Table 4.4.7 */
static void pulse_data(pulse_info *pul, bitfile *ld)
{
uint8_t i;
pul->number_pulse = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,56,"pulse_data(): number_pulse"));
pul->pulse_start_sfb = (uint8_t)faad_getbits(ld, 6
DEBUGVAR(1,57,"pulse_data(): pulse_start_sfb"));
for (i = 0; i < pul->number_pulse+1; i++) {
pul->pulse_offset[i] = (uint8_t)faad_getbits(ld, 5
DEBUGVAR(1,58,"pulse_data(): pulse_offset"));
pul->pulse_amp[i] = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,59,"pulse_data(): pulse_amp"));
}
}
/* Table 4.4.10 */
uint16_t data_stream_element(bitfile *ld)
{
uint8_t byte_aligned;
uint16_t i, count;
/* element_instance_tag = */ faad_getbits(ld, LEN_TAG
DEBUGVAR(1,60,"data_stream_element(): element_instance_tag"));
byte_aligned = faad_get1bit(ld
DEBUGVAR(1,61,"data_stream_element(): byte_aligned"));
count = faad_getbits(ld, 8
DEBUGVAR(1,62,"data_stream_element(): count"));
if (count == 255)
{
count += faad_getbits(ld, 8
DEBUGVAR(1,63,"data_stream_element(): extra count"));
}
if (byte_aligned)
faad_byte_align(ld);
for (i = 0; i < count; i++)
{
faad_getbits(ld, LEN_BYTE
DEBUGVAR(1,64,"data_stream_element(): data_stream_byte"));
}
return count;
}
/* Table 4.4.11 */
uint8_t fill_element(bitfile *ld, drc_info *drc
#ifdef SBR
,uint8_t next_ele_id
#endif
)
{
uint16_t count;
#ifdef SBR
uint8_t bs_extension_type;
uint32_t btot;
#endif
count = (uint16_t)faad_getbits(ld, 4
DEBUGVAR(1,65,"fill_element(): count"));
if (count == 15)
{
count += (uint16_t)faad_getbits(ld, 8
DEBUGVAR(1,66,"fill_element(): extra count")) - 1;
}
#ifdef SBR
bs_extension_type = (uint8_t)faad_showbits(ld, 4);
if (bs_extension_type == SBR_HDR || bs_extension_type == SBR_STD)
{
uint16_t i;
uint16_t bytes, bits;
/* flush the extension type and the fill nibble */
faad_flushbits(ld, 8);
btot = faad_get_processed_bits(ld);
/* SBR bitstream reading function */
sbr_bitstream(next_ele_id, bs_extension_type);
btot = faad_get_processed_bits(ld) - btot;
/* there might still be some fill bits left to read */
bits = (8*(count-1) - btot) % 8;
bytes = ((8*(count-1) - btot) - bits) / 8;
if (bits > 0)
faad_flushbits(ld, bits);
for (i = 0; i < bytes; i++)
{
faad_flushbits(ld, 8);
}
} else {
#endif
while (count > 0)
{
count -= extension_payload(ld, drc, count);
}
#ifdef SBR
}
#endif
return 0;
}
/* Table 4.4.24 */
static uint8_t individual_channel_stream(element *ele, bitfile *ld,
ic_stream *ics, uint8_t scal_flag,
int16_t *spec_data, uint8_t sf_index,
uint8_t object_type
#ifdef ERROR_RESILIENCE
,uint8_t aacSpectralDataResilienceFlag
#endif
)
{
uint8_t result;
uint16_t frame_len =
#ifdef LD_DEC
(object_type == LD) ? 512 :
#endif
1024;
ics->global_gain = (uint8_t)faad_getbits(ld, 8
DEBUGVAR(1,67,"individual_channel_stream(): global_gain"));
if (!ele->common_window && !scal_flag)
{
if ((result = ics_info(ics, ld, ele->common_window, sf_index,
object_type)) > 0)
return result;
}
section_data(ics, ld);
if ((result = scale_factor_data(ics, ld)) > 0)
return result;
if (!scal_flag)
{
/**
** NOTE: It could be that pulse data is available in scalable AAC too,
** as said in Amendment 1, this could be only the case for ER AAC,
** though. (have to check this out later)
**/
/* get pulse data */
if ((ics->pulse_data_present = faad_get1bit(ld
DEBUGVAR(1,68,"individual_channel_stream(): pulse_data_present"))) & 1)
{
pulse_data(&(ics->pul), ld);
}
/* get tns data */
if ((ics->tns_data_present = faad_get1bit(ld
DEBUGVAR(1,69,"individual_channel_stream(): tns_data_present"))) & 1)
{
tns_data(ics, &(ics->tns), ld);
}
/* get gain control data */
if ((ics->gain_control_data_present = faad_get1bit(ld
DEBUGVAR(1,70,"individual_channel_stream(): gain_control_data_present"))) & 1)
{
return 1;
}
}
#ifdef ERROR_RESILIENCE
if (!aacSpectralDataResilienceFlag)
{
#endif
/* decode the spectral data */
if ((result = spectral_data(ics, ld, spec_data, frame_len)) > 0)
return result;
#ifdef ERROR_RESILIENCE
} else {
ics->length_of_reordered_spectral_data = (uint8_t)faad_getbits(ld, 14
DEBUGVAR(1,147,"individual_channel_stream(): length_of_reordered_spectral_data"));
ics->length_of_longest_codeword = (uint8_t)faad_getbits(ld, 6
DEBUGVAR(1,148,"individual_channel_stream(): length_of_longest_codeword"));
/* error resilient spectral data decoding */
if ((result = reordered_spectral_data()) > 0)
return result;
}
#endif
/* pulse coding reconstruction */
if (ics->pulse_data_present)
{
if (ics->window_sequence != EIGHT_SHORT_SEQUENCE)
pulse_decode(ics, spec_data);
else
return 2; /* pulse coding not allowed for long blocks */
}
return 0;
}
/* Table 4.4.25 */
static void section_data(ic_stream *ics, bitfile *ld
#ifdef ERROR_RESILIENCE
,uint8_t aacSectionDataResilienceFlag
#endif
)
{
uint8_t g;
uint8_t sect_esc_val, sect_bits;
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
sect_bits = 3;
else
sect_bits = 5;
sect_esc_val = (1<<sect_bits) - 1;
for (g = 0; g < ics->num_window_groups; g++)
{
uint16_t k = 0;
uint8_t i = 0;
while (k < ics->max_sfb)
{
uint8_t sfb;
uint8_t sect_len_incr;
uint16_t sect_len = 0;
uint8_t sect_cb_bits = 4;
#ifdef ERROR_RESILIENCE
if (aacSectionDataResilienceFlag)
sect_cb_bits = 5;
#endif
ics->sect_cb[g][i] = (uint8_t)faad_getbits(ld, sect_cb_bits
DEBUGVAR(1,71,"section_data(): sect_cb"));
#ifdef ERROR_RESILIENCE
if (!aacSectionDataResilienceFlag ||
(ics->sect_cb[g][i] < 11) ||
(ics->sect_cb[g][i] > 11 && ics->sect_cb[g][i] < 16))
{
#endif
while ((sect_len_incr = (uint8_t)faad_getbits(ld, sect_bits
DEBUGVAR(1,72,"section_data(): sect_len_incr"))) == sect_esc_val)
{
sect_len += sect_esc_val;
}
#ifdef ERROR_RESILIENCE
} else {
sect_len_incr = 1;
}
#endif
sect_len += sect_len_incr;
ics->sect_start[g][i] = k;
ics->sect_end[g][i] = k + sect_len;
for (sfb = k; sfb < k + sect_len; sfb++)
ics->sfb_cb[g][sfb] = ics->sect_cb[g][i];
k += sect_len;
i++;
}
ics->num_sec[g] = i;
}
}
/*
* decode_scale_factors()
* decodes the scalefactors from the bitstream
*/
/*
* All scalefactors (and also the stereo positions and pns energies) are
* transmitted using Huffman coded DPCM relative to the previous active
* scalefactor (respectively previous stereo position or previous pns energy,
* see subclause 4.6.2 and 4.6.3). The first active scalefactor is
* differentially coded relative to the global gain.
*/
static uint8_t decode_scale_factors(ic_stream *ics, bitfile *ld)
{
uint8_t g, sfb;
int8_t t;
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;
for (g = 0; g < ics->num_window_groups; g++)
{
for (sfb = 0; sfb < ics->max_sfb; sfb++)
{
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:
/* decode intensity position */
t = huffman_scale_factor(ld) - 60;
is_position += t;
ics->scale_factors[g][sfb] = is_position;
break;
case NOISE_HCB: /* noise books */
/* decode noise energy */
if (noise_pcm_flag)
{
noise_pcm_flag = 0;
t = faad_getbits(ld, 9
DEBUGVAR(1,73,"scale_factor_data(): first noise")) - 256;
} else {
t = huffman_scale_factor(ld) - 60;
}
noise_energy += t;
ics->scale_factors[g][sfb] = noise_energy;
break;
case BOOKSCL: /* invalid books */
return 3;
default: /* spectral books */
/* decode scale factor */
t = huffman_scale_factor(ld) - 60;
scale_factor += t;
if (scale_factor < 0)
return 4;
ics->scale_factors[g][sfb] = scale_factor;
break;
}
}
}
return 0;
}
/* Table 4.4.26 */
static uint8_t scale_factor_data(ic_stream *ics, bitfile *ld
#ifdef ERROR_RESILIENCE
,uint8_t aacScalefactorDataResilienceFlag
#endif
)
{
#ifdef ERROR_RESILIENCE
if (!aacScalefactorDataResilienceFlag)
{
#endif
return decode_scale_factors(ics, ld);
#ifdef ERROR_RESILIENCE
} else {
uint32_t bits_used, length_of_rvlc_sf;
uint8_t bits = 11;
sf_concealment = faad_get1bit(ld
DEBUGVAR(1,149,"scale_factor_data(): sf_concealment"));
rev_global_gain = faad_getbits(ld, 8
DEBUGVAR(1,150,"scale_factor_data(): rev_global_gain"));
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
bits = 9;
/* the number of bits used for the huffman codewords */
length_of_rvlc_sf = faad_getbits(ld, bits
DEBUGVAR(1,151,"scale_factor_data(): length_of_rvlc_sf"));
/* check how many bits are used in decoding the scalefactors
A better solution would be to read length_of_rvlc_sf ahead
in a buffer and use that to decode the scale factors
*/
bits_used = faad_get_processed_bits(ld);
decode_scale_factors(ics, ld);
bits_used = faad_get_processed_bits(ld) - bits_used;
/* return an error if the number of decoded bits is not correct
FAAD should be able to recover from this, for example by
setting all scalefactors to 0 (e.g. muting the frame)
*/
if (bits_used != length_of_rvlc_sf)
return 8;
sf_escapes_present; 1 uimsbf
if (sf_escapes_present)
{
length_of_rvlc_escapes; 8 uimsbf
for (g = 0; g < num_window_groups; g++)
{
for (sfb = 0; sfb < max_sfb; sfb++)
{
if (sect_cb[g][sfb] != ZERO_HCB)
{
if (is_intensity(g, sfb) &&
dpcm_is_position[g][sfb] == ESC_FLAG)
{
rvlc_esc_sf[dpcm_is_position[g][sfb]]; 2..20 vlclbf
} else {
if (is_noise(g, sfb) &&
dpcm_noise_nrg[g][sfb] == ESC_FLAG)
{
rvlc_esc_sf[dpcm_noise_nrg[g][sfb]]; 2..20 vlclbf
} else {
if (dpcm_sf[g][sfb] == ESC_FLAG)
{
rvlc_esc_sf[dpcm_sf[g][sfb]]; 2..20 vlclbf
}
}
}
}
}
}
if (intensity_used &&
dpcm_is_position[g][sfb] == ESC_FLAG)
{
rvlc_esc_sf[dpcm_is_last_position]; 2..20 vlclbf
}
}
if (noise_used)
{
dpcm_noise_last_position; 9 uimsbf
}
}
#endif
}
/* Table 4.4.27 */
static void tns_data(ic_stream *ics, tns_info *tns, bitfile *ld)
{
uint8_t w, filt, i, start_coef_bits, coef_bits;
uint8_t n_filt_bits = 2;
uint8_t length_bits = 6;
uint8_t order_bits = 5;
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
{
n_filt_bits = 1;
length_bits = 4;
order_bits = 3;
}
for (w = 0; w < ics->num_windows; w++)
{
tns->n_filt[w] = (uint8_t)faad_getbits(ld, n_filt_bits
DEBUGVAR(1,74,"tns_data(): n_filt"));
if (tns->n_filt[w])
{
if ((tns->coef_res[w] = faad_get1bit(ld
DEBUGVAR(1,75,"tns_data(): coef_res"))) & 1)
{
start_coef_bits = 4;
} else {
start_coef_bits = 3;
}
}
for (filt = 0; filt < tns->n_filt[w]; filt++)
{
tns->length[w][filt] = (uint8_t)faad_getbits(ld, length_bits
DEBUGVAR(1,76,"tns_data(): length"));
tns->order[w][filt] = (uint8_t)faad_getbits(ld, order_bits
DEBUGVAR(1,77,"tns_data(): order"));
if (tns->order[w][filt])
{
tns->direction[w][filt] = faad_get1bit(ld
DEBUGVAR(1,78,"tns_data(): direction"));
tns->coef_compress[w][filt] = faad_get1bit(ld
DEBUGVAR(1,79,"tns_data(): coef_compress"));
coef_bits = start_coef_bits - tns->coef_compress[w][filt];
for (i = 0; i < tns->order[w][filt]; i++)
{
tns->coef[w][filt][i] = (uint8_t)faad_getbits(ld, coef_bits
DEBUGVAR(1,80,"tns_data(): coef"));
}
}
}
}
}
#ifdef LTP_DEC
/* Table 4.4.28 */
/*
The limit MAX_LTP_SFB is not defined in 14496-3, this is a bug in the document
and will be corrected in one of the corrigenda.
*/
static void ltp_data(ic_stream *ics, ltp_info *ltp, bitfile *ld,
uint8_t object_type)
{
uint8_t sfb, w;
#ifdef LD_DEC
if (object_type == LD)
{
ltp->lag_update = (uint8_t)faad_getbits(ld, 1
DEBUGVAR(1,142,"ltp_data(): lag_update"));
if (ltp->lag_update)
{
ltp->lag = (uint16_t)faad_getbits(ld, 10
DEBUGVAR(1,81,"ltp_data(): lag"));
}
} else {
#endif
ltp->lag = (uint16_t)faad_getbits(ld, 11
DEBUGVAR(1,81,"ltp_data(): lag"));
#ifdef LD_DEC
}
#endif
ltp->coef = (uint8_t)faad_getbits(ld, 3
DEBUGVAR(1,82,"ltp_data(): coef"));
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
{
for (w = 0; w < ics->num_windows; w++)
{
if ((ltp->short_used[w] = faad_get1bit(ld
DEBUGVAR(1,83,"ltp_data(): short_used"))) & 1)
{
ltp->short_lag_present[w] = faad_get1bit(ld
DEBUGVAR(1,84,"ltp_data(): short_lag_present"));
if (ltp->short_lag_present[w])
{
ltp->short_lag[w] = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,85,"ltp_data(): short_lag"));
}
}
}
} else {
ltp->last_band = (ics->max_sfb < MAX_LTP_SFB ? ics->max_sfb : MAX_LTP_SFB);
for (sfb = 0; sfb < ltp->last_band; sfb++)
{
ltp->long_used[sfb] = faad_get1bit(ld
DEBUGVAR(1,86,"ltp_data(): long_used"));
}
}
}
#endif
/* defines whether a huffman codebook is unsigned or not */
/* Table 4.6.2 */
static uint8_t unsigned_cb[] = { 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0 };
/* Table 4.4.29 */
static uint8_t spectral_data(ic_stream *ics, bitfile *ld, int16_t *spectral_data,
uint16_t frame_len)
{
int8_t i;
uint8_t g, inc;
int16_t *sp;
uint16_t k, p = 0;
uint8_t groups = 0;
uint8_t sect_cb;
sp = spectral_data;
for (i = frame_len/16-1; i >= 0; --i)
{
*sp++ = 0; *sp++ = 0; *sp++ = 0; *sp++ = 0;
*sp++ = 0; *sp++ = 0; *sp++ = 0; *sp++ = 0;
*sp++ = 0; *sp++ = 0; *sp++ = 0; *sp++ = 0;
*sp++ = 0; *sp++ = 0; *sp++ = 0; *sp++ = 0;
}
for(g = 0; g < ics->num_window_groups; g++)
{
p = groups*128;
for (i = 0; i < ics->num_sec[g]; i++)
{
sect_cb = ics->sect_cb[g][i];
if ((sect_cb == ZERO_HCB) ||
(sect_cb == NOISE_HCB) ||
(sect_cb == INTENSITY_HCB) ||
(sect_cb == INTENSITY_HCB2))
{
p += (ics->sect_sfb_offset[g][ics->sect_end[g][i]] -
ics->sect_sfb_offset[g][ics->sect_start[g][i]]);
} else {
for (k = ics->sect_sfb_offset[g][ics->sect_start[g][i]];
k < ics->sect_sfb_offset[g][ics->sect_end[g][i]]; )
{
sp = spectral_data + p;
inc = (sect_cb < FIRST_PAIR_HCB) ? QUAD_LEN : PAIR_LEN;
huffman_spectral_data(sect_cb, ld, sp);
if (unsigned_cb[sect_cb])
huffman_sign_bits(ld, sp, inc);
k += inc;
p += inc;
if (sect_cb == ESC_HCB)
{
sp[0] = huffman_getescape(ld, sp[0]);
sp[1] = huffman_getescape(ld, sp[1]);
}
}
}
}
groups += ics->window_group_length[g];
}
return 0;
}
#ifdef ERROR_RESILIENCE
/* Table 156 */
static uint8_t reordered_spectral_data()
{
}
#endif
/* Table 4.4.30 */
static uint16_t extension_payload(bitfile *ld, drc_info *drc, uint16_t count)
{
uint16_t i, n;
uint8_t extension_type = faad_getbits(ld, 4
DEBUGVAR(1,87,"extension_payload(): extension_type"));
switch (extension_type)
{
case EXT_DYNAMIC_RANGE:
drc->present = 1;
n = dynamic_range_info(ld, drc);
return n;
case EXT_FILL_DATA:
/* fill_nibble = */ faad_getbits(ld, 4
DEBUGVAR(1,136,"extension_payload(): fill_nibble")); /* must be �0000� */
for (i = 0; i < count-1; i++)
{
/* fill_byte[i] = */ faad_getbits(ld, 8
DEBUGVAR(1,88,"extension_payload(): fill_byte")); /* must be �10100101� */
}
return count;
default:
faad_getbits(ld, 4
DEBUGVAR(1,137,"extension_payload(): fill_nibble"));
for (i = 0; i < count-1; i++)
{
/* other_bits[i] = */ faad_getbits(ld, 8
DEBUGVAR(1,89,"extension_payload(): fill_byte"));
}
return count;
}
}
/* Table 4.4.31 */
static uint8_t dynamic_range_info(bitfile *ld, drc_info *drc)
{
uint8_t i, n = 1;
uint8_t band_incr;
drc->num_bands = 1;
if (faad_get1bit(ld
DEBUGVAR(1,90,"dynamic_range_info(): has instance_tag")) & 1)
{
drc->pce_instance_tag = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,91,"dynamic_range_info(): pce_instance_tag"));
/* drc->drc_tag_reserved_bits = */ faad_getbits(ld, 4
DEBUGVAR(1,92,"dynamic_range_info(): drc_tag_reserved_bits"));
n++;
}
drc->excluded_chns_present = faad_get1bit(ld
DEBUGVAR(1,93,"dynamic_range_info(): excluded_chns_present"));
if (drc->excluded_chns_present == 1)
{
n += excluded_channels(ld, drc);
}
if (faad_get1bit(ld
DEBUGVAR(1,94,"dynamic_range_info(): has bands data")) & 1)
{
band_incr = faad_getbits(ld, 4
DEBUGVAR(1,95,"dynamic_range_info(): band_incr"));
/* drc->drc_bands_reserved_bits = */ faad_getbits(ld, 4
DEBUGVAR(1,96,"dynamic_range_info(): drc_bands_reserved_bits"));
n++;
drc->num_bands += band_incr;
for (i = 0; i < drc->num_bands; i++);
{
drc->band_top[i] = (uint8_t)faad_getbits(ld, 8
DEBUGVAR(1,97,"dynamic_range_info(): band_top"));
n++;
}
}
if (faad_get1bit(ld
DEBUGVAR(1,98,"dynamic_range_info(): has prog_ref_level")) & 1)
{
drc->prog_ref_level = (uint8_t)faad_getbits(ld, 7
DEBUGVAR(1,99,"dynamic_range_info(): prog_ref_level"));
/* drc->prog_ref_level_reserved_bits = */ faad_get1bit(ld
DEBUGVAR(1,100,"dynamic_range_info(): prog_ref_level_reserved_bits"));
n++;
}
for (i = 0; i < drc->num_bands; i++)
{
drc->dyn_rng_sgn[i] = faad_get1bit(ld
DEBUGVAR(1,101,"dynamic_range_info(): dyn_rng_sgn"));
drc->dyn_rng_ctl[i] = (uint8_t)faad_getbits(ld, 7
DEBUGVAR(1,102,"dynamic_range_info(): dyn_rng_ctl"));
n++;
}
return n;
}
/* Table 4.4.32 */
static uint8_t excluded_channels(bitfile *ld, drc_info *drc)
{
uint8_t i, n = 0;
uint8_t num_excl_chan = 7;
for (i = 0; i < 7; i++)
{
drc->exclude_mask[i] = faad_get1bit(ld
DEBUGVAR(1,103,"excluded_channels(): exclude_mask"));
}
n++;
while ((drc->additional_excluded_chns[n-1] = faad_get1bit(ld
DEBUGVAR(1,104,"excluded_channels(): additional_excluded_chns"))) == 1)
{
for (i = num_excl_chan; i < num_excl_chan+7; i++)
{
drc->exclude_mask[i] = faad_get1bit(ld
DEBUGVAR(1,105,"excluded_channels(): exclude_mask"));
}
n++;
num_excl_chan += 7;
}
return n;
}
/* Annex A: Audio Interchange Formats */
/* Table 1.A.2 */
void get_adif_header(adif_header *adif, bitfile *ld)
{
uint8_t i;
/* adif_id[0] = */ faad_getbits(ld, 8
DEBUGVAR(1,106,"get_adif_header(): adif_id[0]"));
/* adif_id[1] = */ faad_getbits(ld, 8
DEBUGVAR(1,107,"get_adif_header(): adif_id[1]"));
/* adif_id[2] = */ faad_getbits(ld, 8
DEBUGVAR(1,108,"get_adif_header(): adif_id[2]"));
/* adif_id[3] = */ faad_getbits(ld, 8
DEBUGVAR(1,109,"get_adif_header(): adif_id[3]"));
adif->copyright_id_present = faad_get1bit(ld
DEBUGVAR(1,110,"get_adif_header(): copyright_id_present"));
if(adif->copyright_id_present)
{
for (i = 0; i < 72/8; i++)
{
adif->copyright_id[i] = (int8_t)faad_getbits(ld, 8
DEBUGVAR(1,111,"get_adif_header(): copyright_id"));
}
adif->copyright_id[i] = 0;
}
adif->original_copy = faad_get1bit(ld
DEBUGVAR(1,112,"get_adif_header(): original_copy"));
adif->home = faad_get1bit(ld
DEBUGVAR(1,113,"get_adif_header(): home"));
adif->bitstream_type = faad_get1bit(ld
DEBUGVAR(1,114,"get_adif_header(): bitstream_type"));
adif->bitrate = faad_getbits(ld, 23
DEBUGVAR(1,115,"get_adif_header(): bitrate"));
adif->num_program_config_elements = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,116,"get_adif_header(): num_program_config_elements"));
for (i = 0; i < adif->num_program_config_elements + 1; i++)
{
if(adif->bitstream_type == 0)
{
adif->adif_buffer_fullness = faad_getbits(ld, 20
DEBUGVAR(1,117,"get_adif_header(): adif_buffer_fullness"));
} else {
adif->adif_buffer_fullness = 0;
}
program_config_element(&adif->pce, ld);
}
}
/* Table 1.A.5 */
uint8_t adts_frame(adts_header *adts, bitfile *ld)
{
/* faad_byte_align(ld); */
if (adts_fixed_header(adts, ld))
return 5;
adts_variable_header(adts, ld);
adts_error_check(adts, ld);
return 0;
}
/* Table 1.A.6 */
static uint8_t adts_fixed_header(adts_header *adts, bitfile *ld)
{
uint16_t i;
uint8_t sync_err = 1;
/* try to recover from sync errors */
for (i = 0; i < 768; i++)
{
adts->syncword = (uint16_t)faad_showbits(ld, 12);
if (adts->syncword != 0xFFF)
{
faad_getbits(ld, 8
DEBUGVAR(0,0,""));
} else {
sync_err = 0;
faad_getbits(ld, 12
DEBUGVAR(1,118,"adts_fixed_header(): syncword"));
break;
}
}
if (sync_err)
return 5;
adts->id = faad_get1bit(ld
DEBUGVAR(1,119,"adts_fixed_header(): id"));
adts->layer = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,120,"adts_fixed_header(): layer"));
adts->protection_absent = faad_get1bit(ld
DEBUGVAR(1,121,"adts_fixed_header(): protection_absent"));
adts->profile = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,122,"adts_fixed_header(): profile"));
adts->sf_index = (uint8_t)faad_getbits(ld, 4
DEBUGVAR(1,123,"adts_fixed_header(): sf_index"));
adts->private_bit = faad_get1bit(ld
DEBUGVAR(1,124,"adts_fixed_header(): private_bit"));
adts->channel_configuration = (uint8_t)faad_getbits(ld, 3
DEBUGVAR(1,125,"adts_fixed_header(): channel_configuration"));
adts->original = faad_get1bit(ld
DEBUGVAR(1,126,"adts_fixed_header(): original"));
adts->home = faad_get1bit(ld
DEBUGVAR(1,127,"adts_fixed_header(): home"));
if (adts->id == 0)
{
adts->emphasis = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,128,"adts_fixed_header(): emphasis"));
}
return 0;
}
/* Table 1.A.7 */
static void adts_variable_header(adts_header *adts, bitfile *ld)
{
adts->copyright_identification_bit = faad_get1bit(ld
DEBUGVAR(1,129,"adts_variable_header(): copyright_identification_bit"));
adts->copyright_identification_start = faad_get1bit(ld
DEBUGVAR(1,130,"adts_variable_header(): copyright_identification_start"));
adts->aac_frame_length = (uint16_t)faad_getbits(ld, 13
DEBUGVAR(1,131,"adts_variable_header(): aac_frame_length"));
adts->adts_buffer_fullness = (uint16_t)faad_getbits(ld, 11
DEBUGVAR(1,132,"adts_variable_header(): adts_buffer_fullness"));
adts->no_raw_data_blocks_in_frame = (uint8_t)faad_getbits(ld, 2
DEBUGVAR(1,133,"adts_variable_header(): no_raw_data_blocks_in_frame"));
}
/* Table 1.A.8 */
static void adts_error_check(adts_header *adts, bitfile *ld)
{
if (adts->protection_absent == 0)
{
adts->crc_check = (uint16_t)faad_getbits(ld, 16
DEBUGVAR(1,134,"adts_error_check(): crc_check"));
}
}