shithub: aacdec

ref: d04e5193e35696ba1b3de26d4a3070c281c6cbea
dir: /libfaad/syntax.c/

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/*
** 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 1.44 2003/04/15 19:53:42 menno Exp $
**/

/*
   Reads the AAC bitstream as defined in 14496-3 (MPEG-4 Audio)
*/

#include "common.h"
#include "structs.h"

#include <stdlib.h>
#include <string.h>

#include "decoder.h"
#include "syntax.h"
#include "specrec.h"
#include "huffman.h"
#include "bits.h"
#include "data.h"
#include "pulse.h"
#include "analysis.h"
#include "drc.h"
#ifdef ERROR_RESILIENCE
#include "rvlc.h"
#endif


/* Table 4.4.1 */
int8_t GASpecificConfig(bitfile *ld, mp4AudioSpecificConfig *mp4ASC)
{
    program_config pce;

    /* 1024 or 960 */
    mp4ASC->frameLengthFlag = faad_get1bit(ld
        DEBUGVAR(1,138,"GASpecificConfig(): FrameLengthFlag"));

    mp4ASC->dependsOnCoreCoder = faad_get1bit(ld
        DEBUGVAR(1,139,"GASpecificConfig(): DependsOnCoreCoder"));
    if (mp4ASC->dependsOnCoreCoder == 1)
    {
        mp4ASC->coreCoderDelay = (uint16_t)faad_getbits(ld, 14
            DEBUGVAR(1,140,"GASpecificConfig(): CoreCoderDelay"));
    }

    mp4ASC->extensionFlag = faad_get1bit(ld DEBUGVAR(1,141,"GASpecificConfig(): ExtensionFlag"));
    if (mp4ASC->channelsConfiguration == 0)
    {
        program_config_element(&pce, ld);
        mp4ASC->channelsConfiguration = pce.channels;

        if (pce.num_valid_cc_elements)
            return -3;
    }

#ifdef ERROR_RESILIENCE
    if (mp4ASC->extensionFlag == 1)
    {
        /* Error resilience not supported yet */
        if (mp4ASC->objectTypeIndex >= ER_OBJECT_START)
        {
            mp4ASC->aacSectionDataResilienceFlag = faad_get1bit(ld
                DEBUGVAR(1,144,"GASpecificConfig(): aacSectionDataResilienceFlag"));
            mp4ASC->aacScalefactorDataResilienceFlag = faad_get1bit(ld
                DEBUGVAR(1,145,"GASpecificConfig(): aacScalefactorDataResilienceFlag"));
            mp4ASC->aacSpectralDataResilienceFlag = faad_get1bit(ld
                DEBUGVAR(1,146,"GASpecificConfig(): aacSpectralDataResilienceFlag"));

            /* 1 bit: extensionFlag3 */
        }
    }
#endif

    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;
}

element *decode_sce_lfe(faacDecHandle hDecoder,
                        faacDecFrameInfo *hInfo, bitfile *ld,
                        int16_t **spec_data, real_t **spec_coef,
                        uint8_t id_syn_ele)
{
    element *ele;
    uint8_t channels = hDecoder->fr_channels;

    if (channels+1 >= MAX_CHANNELS)
    {
        hInfo->error = 12;
        return NULL;
    }
    if (hDecoder->fr_ch_ele+1 >= MAX_SYNTAX_ELEMENTS)
    {
        hInfo->error = 13;
        return NULL;
    }

    spec_data[channels]   = (int16_t*)malloc(hDecoder->frameLength*sizeof(int16_t));
    spec_coef[channels]   = (real_t*)malloc(hDecoder->frameLength*sizeof(real_t));

    ele = (element*)malloc(sizeof(element));
    memset(ele, 0, sizeof(element));
    ele->ele_id  = id_syn_ele;
    ele->channel = channels;
    ele->paired_channel = -1;

    hInfo->error = single_lfe_channel_element(hDecoder, ele,
        ld, spec_data[channels]);

    hDecoder->fr_channels++;
    hDecoder->fr_ch_ele++;

    return ele;
}

element *decode_cpe(faacDecHandle hDecoder,
                    faacDecFrameInfo *hInfo, bitfile *ld,
                    int16_t **spec_data, real_t **spec_coef,
                    uint8_t id_syn_ele)
{
    element *ele;
    uint8_t channels = hDecoder->fr_channels;

    if (channels+2 >= MAX_CHANNELS)
    {
        hInfo->error = 12;
        return NULL;
    }
    if (hDecoder->fr_ch_ele+1 >= MAX_SYNTAX_ELEMENTS)
    {
        hInfo->error = 13;
        return NULL;
    }

    spec_data[channels]   = (int16_t*)malloc(hDecoder->frameLength*sizeof(int16_t));
    spec_data[channels+1] = (int16_t*)malloc(hDecoder->frameLength*sizeof(int16_t));
    spec_coef[channels]   = (real_t*)malloc(hDecoder->frameLength*sizeof(real_t));
    spec_coef[channels+1] = (real_t*)malloc(hDecoder->frameLength*sizeof(real_t));

    ele = (element*)malloc(sizeof(element));
    memset(ele, 0, sizeof(element));
    ele->ele_id         = id_syn_ele;
    ele->channel        = channels;
    ele->paired_channel = channels+1;

    hInfo->error = channel_pair_element(hDecoder, ele,
        ld, spec_data[channels], spec_data[channels+1]);

    hDecoder->fr_channels += 2;
    hDecoder->fr_ch_ele++;

    return ele;
}

element **raw_data_block(faacDecHandle hDecoder, faacDecFrameInfo *hInfo,
                         bitfile *ld, element **elements,
                         int16_t **spec_data, real_t **spec_coef,
                         program_config *pce, drc_info *drc)
{
    uint8_t id_syn_ele;
    uint8_t ch_ele = 0;

    hDecoder->fr_channels = 0;
    hDecoder->fr_ch_ele = 0;

#ifdef ERROR_RESILIENCE
    if (hDecoder->object_type < ER_OBJECT_START)
    {
#endif
        /* Table 4.4.3: raw_data_block() */
        while ((id_syn_ele = (uint8_t)faad_getbits(ld, LEN_SE_ID
            DEBUGVAR(1,4,"faacDecDecode(): id_syn_ele"))) != ID_END)
        {
            switch (id_syn_ele) {
            case ID_SCE:
            case ID_LFE:
                elements[ch_ele++] = decode_sce_lfe(hDecoder,
                    hInfo, ld, spec_data, spec_coef, id_syn_ele);
                if (hInfo->error > 0)
                    return elements;
                break;
            case ID_CPE:
                elements[ch_ele++] = decode_cpe(hDecoder,
                    hInfo, ld, spec_data, spec_coef, id_syn_ele);
                if (hInfo->error > 0)
                    return elements;
                break;
            case ID_CCE: /* not implemented yet */
                hInfo->error = 6;
                return elements;
            case ID_DSE:
                data_stream_element(ld);
                break;
            case ID_PCE:
                if ((hInfo->error = program_config_element(pce, ld)) > 0)
                    return elements;
                break;
            case ID_FIL:
                if ((hInfo->error = fill_element(ld, drc)) > 0)
                    return elements;
                break;
            }
        }
#ifdef ERROR_RESILIENCE
    } else {
        /* Table 262: er_raw_data_block() */
        switch (hDecoder->channelConfiguration)
        {
        case 1:
            elements[ch_ele++] = decode_sce_lfe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_SCE);
            if (hInfo->error > 0)
                return elements;
            break;
        case 2:
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            if (hInfo->error > 0)
                return elements;
            break;
        case 3:
            elements[ch_ele++] = decode_sce_lfe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_SCE);
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            if (hInfo->error > 0)
                return elements;
            break;
        case 4:
            elements[ch_ele++] = decode_sce_lfe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_SCE);
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            elements[ch_ele++] = decode_sce_lfe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_SCE);
            if (hInfo->error > 0)
                return elements;
            break;
        case 5:
            elements[ch_ele++] = decode_sce_lfe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_SCE);
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            if (hInfo->error > 0)
                return elements;
            break;
        case 6:
            elements[ch_ele++] = decode_sce_lfe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_SCE);
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            elements[ch_ele++] = decode_sce_lfe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_LFE);
            if (hInfo->error > 0)
                return elements;
            break;
        case 7:
            elements[ch_ele++] = decode_sce_lfe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_SCE);
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            elements[ch_ele++] = decode_cpe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_CPE);
            elements[ch_ele++] = decode_sce_lfe(hDecoder,
                hInfo, ld, spec_data, spec_coef, ID_LFE);
            if (hInfo->error > 0)
                return elements;
            break;
        default:
            hInfo->error = 7;
            return elements;
        }
#if 0
        cnt = bits_to_decode() / 8;
        while (cnt >= 1)
        {
            cnt -= extension_payload(cnt);
        }
#endif
    }
#endif

    /* new in corrigendum 14496-3:2002 */
    faad_byte_align(ld);

    return elements;
}

#ifdef DRM
static uint8_t faad_check_CRC(bitfile *ld)
{
    uint16_t len = faad_get_processed_bits(ld) - 8;
    uint8_t CRC;
    uint16_t r=255;  /* Initialize to all ones */

    /* CRC polynome used x^8 + x^4 + x^3 + x^2 +1 */
#define GPOLY 0435

    faad_rewindbits(ld);

    CRC = ~faad_getbits(ld, 8
        DEBUGVAR(1,999,"faad_check_CRC(): CRC"));          /* CRC is stored inverted */

    for (; len>0; len--)
    {
        r = ( (r << 1) ^ (( ( faad_get1bit(ld
            DEBUGVAR(1,998,""))  & 1) ^ ((r >> 7) & 1)) * GPOLY )) & 0xFF;
    }
    if (r != CRC)
    {
        return 8;
    } else {
        return 0;
    }
}
#endif

/* Table 4.4.4 and */
/* Table 4.4.9 */
static uint8_t single_lfe_channel_element(faacDecHandle hDecoder,
                                          element *sce, bitfile *ld,
                                          int16_t *spec_data)
{
    ic_stream *ics = &(sce->ics1);
#ifdef DRM
    uint8_t result;

    if (hDecoder->object_type != DRM_ER_LC)
#endif
    sce->element_instance_tag = (uint8_t)faad_getbits(ld, LEN_TAG
        DEBUGVAR(1,38,"single_lfe_channel_element(): element_instance_tag"));

#ifdef DRM
    if (hDecoder->object_type == DRM_ER_LC)
    {
        individual_channel_stream(hDecoder, sce, ld, ics, 0, spec_data);

        if (ics->tns_data_present)
            tns_data(ics, &(ics->tns), ld);

        if ((result = faad_check_CRC( ld )) > 0)
            return result;

        /* error resilient spectral data decoding */
        if ((result = reordered_spectral_data(hDecoder, ics, ld, spec_data)) > 0)
            return result;

        /* pulse coding reconstruction */
        if (ics->pulse_data_present)
        {
            if (ics->window_sequence != EIGHT_SHORT_SEQUENCE)
            {
                if ((result = pulse_decode(ics, spec_data, hDecoder->frameLength)) > 0)
                    return result;
            } else {
                return 2; /* pulse coding not allowed for short blocks */
            }
        }
        return 0;
    } else
#endif

    return individual_channel_stream(hDecoder, sce, ld, ics, 0, spec_data);
}

/* Table 4.4.5 */
static uint8_t channel_pair_element(faacDecHandle hDecoder, element *cpe,
                                    bitfile *ld, int16_t *spec_data1,
                                    int16_t *spec_data2)
{
    uint8_t result;
    ic_stream *ics1 = &(cpe->ics1);
    ic_stream *ics2 = &(cpe->ics2);

#ifdef DRM
    if (hDecoder->object_type != DRM_ER_LC)
#endif
    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(hDecoder, ics1, ld, cpe->common_window)) > 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"));
                }
            }
        }

#ifdef ERROR_RESILIENCE
        if ((hDecoder->object_type >= ER_OBJECT_START) && (ics1->predictor_data_present))
        {
            if ((ics1->ltp.data_present = faad_get1bit(ld
                DEBUGVAR(1,50,"channel_pair_element(): ltp.data_present"))) & 1)
            {
                ltp_data(hDecoder, ics1, &(ics1->ltp), ld);
            }
        }
#endif

        memcpy(ics2, ics1, sizeof(ic_stream));
    } else {
        ics1->ms_mask_present = 0;
    }

    if ((result = individual_channel_stream(hDecoder, cpe, ld, ics1,
        0, spec_data1)) > 0)
    {
        return result;
    }

#ifdef ERROR_RESILIENCE
    if (cpe->common_window && (hDecoder->object_type >= ER_OBJECT_START) &&
        (ics1->predictor_data_present))
    {
        if ((ics1->ltp2.data_present = faad_get1bit(ld
            DEBUGVAR(1,50,"channel_pair_element(): ltp.data_present"))) & 1)
        {
            ltp_data(hDecoder, ics1, &(ics1->ltp2), ld);
        }
    }
#endif

    if ((result = individual_channel_stream(hDecoder, cpe, ld, ics2,
        0, spec_data2)) > 0)
    {
        return result;
    }

#ifdef DRM
    if (hDecoder->object_type == DRM_ER_LC)
    {
        if (ics1->tns_data_present)
            tns_data(ics1, &(ics1->tns), ld);

        if (ics1->tns_data_present)
            tns_data(ics2, &(ics2->tns), ld);

        if ((result = faad_check_CRC( ld )) > 0)
        {
            return result;
        }
        /* error resilient spectral data decoding */
        if ((result = reordered_spectral_data(hDecoder, ics1, ld, spec_data1)) > 0)
            return result;
        if ((result = reordered_spectral_data(hDecoder, ics2, ld, spec_data2)) > 0)
            return result;
        /* pulse coding reconstruction */
        if (ics1->pulse_data_present)
        {
            if (ics1->window_sequence != EIGHT_SHORT_SEQUENCE)
            {
                if ((result = pulse_decode(ics1, spec_data1, hDecoder->frameLength)) > 0)
                    return result;
            } else {
                return 2; /* pulse coding not allowed for short blocks */
            }
        }
        if (ics2->pulse_data_present)
        {
            if (ics2->window_sequence != EIGHT_SHORT_SEQUENCE)
            {
                if ((result = pulse_decode(ics2, spec_data2, hDecoder->frameLength)) > 0)
                    return result;
            } else {
                return 2; /* pulse coding not allowed for short blocks */
            }
        }
        return 0;
    } else
#endif

    return 0;
}

/* Table 4.4.6 */
static uint8_t ics_info(faacDecHandle hDecoder, ic_stream *ics, bitfile *ld,
                        uint8_t common_window)
{
    uint8_t retval = 0;

    /* 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)"));
    }

    /* get the grouping information */
    if ((retval = window_grouping_info(hDecoder, ics)) > 0)
        return retval;

    /* should be an error */
    /* check the range of max_sfb */
    if (ics->max_sfb > ics->num_swb)
        return 16;

    if (ics->window_sequence != EIGHT_SHORT_SEQUENCE)
    {
        if ((ics->predictor_data_present = faad_get1bit(ld
            DEBUGVAR(1,49,"ics_info(): predictor_data_present"))) & 1)
        {
            if (hDecoder->object_type == MAIN) /* MPEG2 style AAC predictor */
            {
                uint8_t sfb;

                ics->pred.limit = min(ics->max_sfb, pred_sfb_max[hDecoder->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 (hDecoder->object_type < ER_OBJECT_START)
                {
                    if ((ics->ltp.data_present = faad_get1bit(ld
                        DEBUGVAR(1,50,"ics_info(): ltp.data_present"))) & 1)
                    {
                        ltp_data(hDecoder, ics, &(ics->ltp), ld);
                    }
                    if (common_window)
                    {
                        if ((ics->ltp2.data_present = faad_get1bit(ld
                            DEBUGVAR(1,51,"ics_info(): ltp2.data_present"))) & 1)
                        {
                            ltp_data(hDecoder, ics, &(ics->ltp2), ld);
                        }
                    }
                }
#ifdef ERROR_RESILIENCE
                if (!common_window && (hDecoder->object_type >= ER_OBJECT_START))
                {
                    if ((ics->ltp.data_present = faad_get1bit(ld
                        DEBUGVAR(1,50,"ics_info(): ltp.data_present"))) & 1)
                    {
                        ltp_data(hDecoder, ics, &(ics->ltp), ld);
                    }
                }
#endif
            }
#endif
        }
    }

    return retval;
}

/* Table 4.4.7 */
static uint8_t pulse_data(ic_stream *ics, 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"));

    /* check the range of pulse_start_sfb */
    if (pul->pulse_start_sfb > ics->num_swb)
        return 16;

    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"));
    }

    return 0;
}

/* Table 4.4.10 */
static 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 = (uint16_t)faad_getbits(ld, 8
        DEBUGVAR(1,62,"data_stream_element(): count"));
    if (count == 255)
    {
        count += (uint16_t)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 */
static uint8_t fill_element(bitfile *ld, drc_info *drc)
{
    uint16_t count;

    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;
    }

    while (count > 0)
    {
        count -= extension_payload(ld, drc, count);
    }

    return 0;
}

/* Table 4.4.12 */
#ifdef SSR_DEC
static void gain_control_data(bitfile *ld, ic_stream *ics)
{
    uint8_t bd, wd, ad;
    ssr_info *ssr = &(ics->ssr);

    ssr->max_band = (uint8_t)faad_getbits(ld, 2
        DEBUGVAR(1,1000,"gain_control_data(): max_band"));

    if (ics->window_sequence == ONLY_LONG_SEQUENCE)
    {
        for (bd = 1; bd <= ssr->max_band; bd++)
        {
            for (wd = 0; wd < 1; wd++)
            {
                ssr->adjust_num[bd][wd] = (uint8_t)faad_getbits(ld, 3
                    DEBUGVAR(1,1001,"gain_control_data(): adjust_num"));

                for (ad = 0; ad < ssr->adjust_num[bd][wd]; ad++)
                {
                    ssr->alevcode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 4
                        DEBUGVAR(1,1002,"gain_control_data(): alevcode"));
                    ssr->aloccode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 5
                        DEBUGVAR(1,1003,"gain_control_data(): aloccode"));
                }
            }
        }
    } else if (ics->window_sequence == LONG_START_SEQUENCE) {
        for (bd = 1; bd <= ssr->max_band; bd++)
        {
            for (wd = 0; wd < 2; wd++)
            {
                ssr->adjust_num[bd][wd] = (uint8_t)faad_getbits(ld, 3
                    DEBUGVAR(1,1001,"gain_control_data(): adjust_num"));

                for (ad = 0; ad < ssr->adjust_num[bd][wd]; ad++)
                {
                    ssr->alevcode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 4
                        DEBUGVAR(1,1002,"gain_control_data(): alevcode"));
                    if (wd == 0)
                    {
                        ssr->aloccode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 4
                            DEBUGVAR(1,1003,"gain_control_data(): aloccode"));
                    } else {
                        ssr->aloccode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 2
                            DEBUGVAR(1,1003,"gain_control_data(): aloccode"));
                    }
                }
            }
        }
    } else if (ics->window_sequence == EIGHT_SHORT_SEQUENCE) {
        for (bd = 1; bd <= ssr->max_band; bd++)
        {
            for (wd = 0; wd < 8; wd++)
            {
                ssr->adjust_num[bd][wd] = (uint8_t)faad_getbits(ld, 3
                    DEBUGVAR(1,1001,"gain_control_data(): adjust_num"));

                for (ad = 0; ad < ssr->adjust_num[bd][wd]; ad++)
                {
                    ssr->alevcode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 4
                        DEBUGVAR(1,1002,"gain_control_data(): alevcode"));
                    ssr->aloccode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 2
                        DEBUGVAR(1,1003,"gain_control_data(): aloccode"));
                }
            }
        }
    } else if (ics->window_sequence == LONG_STOP_SEQUENCE) {
        for (bd = 1; bd <= ssr->max_band; bd++)
        {
            for (wd = 0; wd < 2; wd++)
            {
                ssr->adjust_num[bd][wd] = (uint8_t)faad_getbits(ld, 3
                    DEBUGVAR(1,1001,"gain_control_data(): adjust_num"));

                for (ad = 0; ad < ssr->adjust_num[bd][wd]; ad++)
                {
                    ssr->alevcode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 4
                        DEBUGVAR(1,1002,"gain_control_data(): alevcode"));

                    if (wd == 0)
                    {
                        ssr->aloccode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 4
                            DEBUGVAR(1,1003,"gain_control_data(): aloccode"));
                    } else {
                        ssr->aloccode[bd][wd][ad] = (uint8_t)faad_getbits(ld, 5
                            DEBUGVAR(1,1003,"gain_control_data(): aloccode"));
                    }
                }
            }
        }
    }
}
#endif

/* Table 4.4.24 */
static uint8_t individual_channel_stream(faacDecHandle hDecoder, element *ele,
                                         bitfile *ld, ic_stream *ics, uint8_t scal_flag,
                                         int16_t *spec_data)
{
    uint8_t result;

    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(hDecoder, ics, ld, ele->common_window)) > 0)
            return result;
    }

    if ((result = section_data(hDecoder, ics, ld)) > 0)
        return result;

    if ((result = scale_factor_data(hDecoder, 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)
        {
            if ((result = pulse_data(ics, &(ics->pul), ld)) > 0)
                return result;
        }

        /* get tns data */
        if ((ics->tns_data_present = faad_get1bit(ld
            DEBUGVAR(1,69,"individual_channel_stream(): tns_data_present"))) & 1)
        {
#ifdef ERROR_RESILIENCE
            if (hDecoder->object_type < ER_OBJECT_START)
#endif
                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)
        {
#ifdef SSR_DEC
            if (hDecoder->object_type != SSR)
                return 1;
            else
                gain_control_data(ld, ics);
#else
            return 1;
#endif
        }
    }

#ifdef ERROR_RESILIENCE
    if (hDecoder->aacSpectralDataResilienceFlag)
    {
        ics->length_of_reordered_spectral_data = (uint16_t)faad_getbits(ld, 14
            DEBUGVAR(1,147,"individual_channel_stream(): length_of_reordered_spectral_data"));

        if (hDecoder->channelConfiguration == 2)
        {
            if (ics->length_of_reordered_spectral_data > 6144)
                ics->length_of_reordered_spectral_data = 6144;
        } else {
            if (ics->length_of_reordered_spectral_data > 12288)
                ics->length_of_reordered_spectral_data = 12288;
        }

        ics->length_of_longest_codeword = (uint8_t)faad_getbits(ld, 6
            DEBUGVAR(1,148,"individual_channel_stream(): length_of_longest_codeword"));
        if (ics->length_of_longest_codeword >= 49)
            ics->length_of_longest_codeword = 49;
    }

    /* RVLC spectral data is put here */
    if (hDecoder->aacScalefactorDataResilienceFlag)
    {
        if ((result = rvlc_decode_scale_factors(ics, ld)) > 0)
            return result;
    }

#ifdef DRM
    if (hDecoder->object_type == DRM_ER_LC)
        return 0;
#endif

    if (hDecoder->object_type >= ER_OBJECT_START) 
    {
        if (ics->tns_data_present)
            tns_data(ics, &(ics->tns), ld);
    }

    if (hDecoder->aacSpectralDataResilienceFlag)
    {
        /* error resilient spectral data decoding */
        if ((result = reordered_spectral_data(hDecoder, ics, ld, spec_data)) > 0)
        {
            return result;
        }
    } else {
#endif
        /* decode the spectral data */
        if ((result = spectral_data(hDecoder, ics, ld, spec_data)) > 0)
        {
            return result;
        }
#ifdef ERROR_RESILIENCE
    }
#endif

    /* pulse coding reconstruction */
    if (ics->pulse_data_present)
    {
        if (ics->window_sequence != EIGHT_SHORT_SEQUENCE)
        {
            if ((result = pulse_decode(ics, spec_data, hDecoder->frameLength)) > 0)
                return result;
        } else {
            return 2; /* pulse coding not allowed for short blocks */
        }
    }

    return 0;
}

/* Table 4.4.25 */
static uint8_t section_data(faacDecHandle hDecoder, ic_stream *ics, bitfile *ld)
{
    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;

#if 0
    printf("\ntotal sfb %d\n", ics->max_sfb);
    printf("   sect    top     cb\n");
#endif

    for (g = 0; g < ics->num_window_groups; g++)
    {
        uint8_t k = 0;
        uint8_t i = 0;

        while (k < ics->max_sfb)
        {
#ifdef ERROR_RESILIENCE
            uint8_t vcb11 = 0;
#endif
            uint8_t sfb;
            uint8_t sect_len_incr;
            uint16_t sect_len = 0;
            uint8_t sect_cb_bits = 4;

            /* if "faad_getbits" detects error and returns "0", "k" is never
               incremented and we cannot leave the while loop */
            if ((ld->error != 0) || (ld->no_more_reading))
                return 14;

#ifdef ERROR_RESILIENCE
            if (hDecoder->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"));

            if (ics->sect_cb[g][i] == NOISE_HCB)
                ics->noise_used = 1;

#ifdef ERROR_RESILIENCE
            if (hDecoder->aacSectionDataResilienceFlag)
            {
                if ((ics->sect_cb[g][i] == 11) ||
                    ((ics->sect_cb[g][i] >= 16) && (ics->sect_cb[g][i] <= 32)))
                {
                    vcb11 = 1;
                }
            }
            if (vcb11)
            {
                sect_len_incr = 1;
            } else {
#endif
                sect_len_incr = (uint8_t)faad_getbits(ld, sect_bits
                    DEBUGVAR(1,72,"section_data(): sect_len_incr"));
#ifdef ERROR_RESILIENCE
            }
#endif
            while ((sect_len_incr == sect_esc_val) /* &&
                (k+sect_len < ics->max_sfb)*/)
            {
                sect_len += sect_len_incr;
                sect_len_incr = (uint8_t)faad_getbits(ld, sect_bits
                    DEBUGVAR(1,72,"section_data(): sect_len_incr"));
            }

            sect_len += sect_len_incr;

            ics->sect_start[g][i] = k;
            ics->sect_end[g][i] = k + sect_len;

            if (k + sect_len >= 8*15)
                return 15;
            if (i >= 8*15)
                return 15;

            for (sfb = k; sfb < k + sect_len; sfb++)
                ics->sfb_cb[g][sfb] = ics->sect_cb[g][i];

#if 0
            printf(" %6d %6d %6d\n",
                i,
                ics->sect_end[g][i],
                ics->sect_cb[g][i]);
#endif

            k += sect_len;
            i++;
        }
        ics->num_sec[g] = i;
    }

#if 0
    printf("\n");
#endif

    return 0;
}

/*
 *  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;
    int16_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);
                if (t < 0)
                    return 9;
                is_position += (t - 60);
                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 = (int16_t)faad_getbits(ld, 9
                        DEBUGVAR(1,73,"scale_factor_data(): first noise")) - 256;
                } else {
                    t = huffman_scale_factor(ld);
                    if (t < 0)
                        return 9;
                    t -= 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);
                if (t < 0)
                    return 9;
                scale_factor += (t - 60);
                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(faacDecHandle hDecoder, ic_stream *ics, bitfile *ld)
{
#ifdef ERROR_RESILIENCE
    if (!hDecoder->aacScalefactorDataResilienceFlag)
    {
#endif
        return decode_scale_factors(ics, ld);
#ifdef ERROR_RESILIENCE
    } else {
        /* In ER AAC the parameters for RVLC are seperated from the actual
           data that holds the scale_factors.
           Strangely enough, 2 parameters for HCR are put inbetween them.
        */
        return rvlc_scale_factor_data(ics, ld);
    }
#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 */
static void ltp_data(faacDecHandle hDecoder, ic_stream *ics, ltp_info *ltp, bitfile *ld)
{
    uint8_t sfb, w;

#ifdef LD_DEC
    if (hDecoder->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

/* Table 4.4.29 */
static uint8_t spectral_data(faacDecHandle hDecoder, ic_stream *ics, bitfile *ld,
                             int16_t *spectral_data)
{
    int8_t i;
    uint8_t g;
    int16_t *sp;
    uint16_t k, p = 0;
    uint8_t groups = 0;
    uint8_t sect_cb;
    uint8_t result;
    uint16_t nshort = hDecoder->frameLength/8;

    sp = spectral_data;
    memset(sp, 0, hDecoder->frameLength*sizeof(int16_t));

    for(g = 0; g < ics->num_window_groups; g++)
    {
        p = groups*nshort;

        for (i = 0; i < ics->num_sec[g]; i++)
        {
            sect_cb = ics->sect_cb[g][i];

            switch (sect_cb)
            {
            case ZERO_HCB:
            case NOISE_HCB:
            case INTENSITY_HCB:
            case INTENSITY_HCB2:
                p += (ics->sect_sfb_offset[g][ics->sect_end[g][i]] -
                    ics->sect_sfb_offset[g][ics->sect_start[g][i]]);
                break;
            default:
                for (k = ics->sect_sfb_offset[g][ics->sect_start[g][i]];
                     k < ics->sect_sfb_offset[g][ics->sect_end[g][i]]; k += 4)
                {
                    sp = spectral_data + p;

                    if (sect_cb < FIRST_PAIR_HCB)
                    {
                        if ((result = huffman_spectral_data(sect_cb, ld, sp)) > 0)
                            return result;
                    } else {
                        if ((result = huffman_spectral_data(sect_cb, ld, sp)) > 0)
                            return result;
                        if ((result = huffman_spectral_data(sect_cb, ld, sp+2)) > 0)
                            return result;
                    }
                    p += 4;
                }
                break;
            }
        }
        groups += ics->window_group_length[g];
    }

    return 0;
}

/* Table 4.4.30 */
static uint16_t extension_payload(bitfile *ld, drc_info *drc, uint16_t count)
{
    uint16_t i, n, dataElementLength;
    uint8_t dataElementLengthPart;
    uint8_t align = 4, data_element_version, loopCounter;

    uint8_t extension_type = (uint8_t)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;
    case EXT_DATA_ELEMENT:
        data_element_version = faad_getbits(ld, 4
            DEBUGVAR(1,400,"extension_payload(): data_element_version"));
        switch (data_element_version)
        {
        case ANC_DATA:
            loopCounter = 0;
            dataElementLength = 0;
            do {
                dataElementLengthPart = faad_getbits(ld, 8
                    DEBUGVAR(1,401,"extension_payload(): dataElementLengthPart"));
                dataElementLength += dataElementLengthPart;
                loopCounter++;
            } while (dataElementLengthPart == 255);

            for (i = 0; i < dataElementLength; i++)
            {
                /* data_element_byte[i] = */ faad_getbits(ld, 8
                    DEBUGVAR(1,402,"extension_payload(): data_element_byte"));
                return (dataElementLength+loopCounter+1);
            }
        default:
            align = 0;
        }
    case EXT_FIL:
    default:
        faad_getbits(ld, align
            DEBUGVAR(1,88,"extension_payload(): fill_nibble"));
        for (i = 0; i < count-1; i++)
        {
            /* other_bits[i] = */ faad_getbits(ld, 8
               DEBUGVAR(1,89,"extension_payload(): fill_bit"));
        }
        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 = (uint8_t)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"));

    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;
    }

    for (i = 0; i < adif->num_program_config_elements + 1; i++)
    {
        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"));
/* Removed in corrigendum 14496-3:2002
    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"));
    }
}