/*

** 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: decoder.c,v 1.119 2015/01/24 14:21:05 knik Exp $

**/

#include "common.h"

#include "structs.h"

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include "mp4.h"

#include "syntax.h"

#include "error.h"

#include "output.h"

#include "filtbank.h"

#include "drc.h"

#ifdef SBR_DEC

#include "sbr_dec.h"

#include "sbr_syntax.h"

#endif

#ifdef SSR_DEC

#include "ssr.h"

#endif

#ifdef ANALYSIS

uint16_t dbg_count;

#endif

#if !defined(PACKAGE_VERSION)

#error "PACKAGE_VERSION must be defined"

#endif

/* static function declarations */

static void* aac_frame_decode(NeAACDecStruct *hDecoder,

                              NeAACDecFrameInfo *hInfo,

                              unsigned char *buffer,

                              unsigned long buffer_size,

                              void **sample_buffer2,

                              unsigned long sample_buffer_size);

static void create_channel_config(NeAACDecStruct *hDecoder,

                                  NeAACDecFrameInfo *hInfo);

int NeAACDecGetVersion(char **faad_id_string,

                                   char **faad_copyright_string)

{

    static char *libfaadName = PACKAGE_VERSION;

    static char *libCopyright =

        " Copyright 2002-2004: Ahead Software AG\n"

  " http://www.audiocoding.com\n"

  " bug tracking: https://sourceforge.net/p/faac/bugs/\n";

    if (faad_id_string)

        *faad_id_string = libfaadName;

    if (faad_copyright_string)

        *faad_copyright_string = libCopyright;

    return 0;

}

char* NeAACDecGetErrorMessage(unsigned char errcode)

{

    if (errcode >= NUM_ERROR_MESSAGES)

        return NULL;

    return err_msg[errcode];

}

unsigned long NeAACDecGetCapabilities(void)

{

    uint32_t cap = 0;

    /* can't do without it */

    cap += LC_DEC_CAP;

#ifdef MAIN_DEC

    cap += MAIN_DEC_CAP;

#endif

#ifdef LTP_DEC

    cap += LTP_DEC_CAP;

#endif

#ifdef LD_DEC

    cap += LD_DEC_CAP;

#endif

#ifdef ERROR_RESILIENCE

    cap += ERROR_RESILIENCE_CAP;

#endif

#ifdef FIXED_POINT

    cap += FIXED_POINT_CAP;

#endif

    return cap;

}

const unsigned char mes[] = { 0x67,0x20,0x61,0x20,0x20,0x20,0x6f,0x20,0x72,0x20,0x65,0x20,0x6e,0x20,0x20,0x20,0x74,0x20,0x68,0x20,0x67,0x20,0x69,0x20,0x72,0x20,0x79,0x20,0x70,0x20,0x6f,0x20,0x63 };

NeAACDecHandle NeAACDecOpen(void)

{

    uint8_t i;

    NeAACDecStruct *hDecoder = NULL;

    if ((hDecoder = (NeAACDecStruct*)faad_malloc(sizeof(NeAACDecStruct))) == NULL)

        return NULL;

    memset(hDecoder, 0, sizeof(NeAACDecStruct));

    hDecoder->cmes = mes;

    hDecoder->config.outputFormat  = FAAD_FMT_16BIT;

    hDecoder->config.defObjectType = MAIN;

    hDecoder->config.defSampleRate = 44100; /* Default: 44.1kHz */

    hDecoder->config.downMatrix = 0;

    hDecoder->adts_header_present = 0;

    hDecoder->adif_header_present = 0;

    hDecoder->latm_header_present = 0;

#ifdef ERROR_RESILIENCE

    hDecoder->aacSectionDataResilienceFlag = 0;

    hDecoder->aacScalefactorDataResilienceFlag = 0;

    hDecoder->aacSpectralDataResilienceFlag = 0;

#endif

    hDecoder->frameLength = 1024;

    hDecoder->frame = 0;

    hDecoder->sample_buffer = NULL;

    // Same as (1, 1) after 1024 iterations; otherwise first values does not look random at all.

    hDecoder->__r1 = 0x2bb431ea;

    hDecoder->__r2 = 0x206155b7;

    for (i = 0; i < MAX_CHANNELS; i++)

    {

        hDecoder->element_id[i] = INVALID_ELEMENT_ID;

        hDecoder->window_shape_prev[i] = 0;

        hDecoder->time_out[i] = NULL;

        hDecoder->fb_intermed[i] = NULL;

#ifdef SSR_DEC

        hDecoder->ssr_overlap[i] = NULL;

        hDecoder->prev_fmd[i] = NULL;

#endif

#ifdef MAIN_DEC

        hDecoder->pred_stat[i] = NULL;

#endif

#ifdef LTP_DEC

        hDecoder->ltp_lag[i] = 0;

        hDecoder->lt_pred_stat[i] = NULL;

#endif

    }

#ifdef SBR_DEC

    for (i = 0; i < MAX_SYNTAX_ELEMENTS; i++)

    {

        hDecoder->sbr[i] = NULL;

    }

#endif

    hDecoder->drc = drc_init(REAL_CONST(1.0), REAL_CONST(1.0));

#if (defined(PS_DEC) || defined(DRM_PS))

    hDecoder->ps_present_flag = -1;

#endif

    return hDecoder;

}

NeAACDecConfigurationPtr NeAACDecGetCurrentConfiguration(NeAACDecHandle hpDecoder)

{

    NeAACDecStruct* hDecoder = (NeAACDecStruct*)hpDecoder;

    if (hDecoder)

    {

        NeAACDecConfigurationPtr config = &(hDecoder->config);

        return config;

    }

    return NULL;

}

unsigned char NeAACDecSetConfiguration(NeAACDecHandle hpDecoder,

                                                   NeAACDecConfigurationPtr config)

{

    NeAACDecStruct* hDecoder = (NeAACDecStruct*)hpDecoder;

    if (hDecoder && config)

    {

        /* check if we can decode this object type */

        if (can_decode_ot(config->defObjectType) < 0)

            return 0;

        hDecoder->config.defObjectType = config->defObjectType;

        /* samplerate: anything but 0 should be possible */

        if (config->defSampleRate == 0)

            return 0;

        hDecoder->config.defSampleRate = config->defSampleRate;

        /* check output format */

#ifdef FIXED_POINT

        if ((config->outputFormat < 1) || (config->outputFormat > 4))

            return 0;

#else

        if ((config->outputFormat < 1) || (config->outputFormat > 5))

            return 0;

#endif

        hDecoder->config.outputFormat = config->outputFormat;

        if (config->downMatrix > 1)

            return 0;

        hDecoder->config.downMatrix = config->downMatrix;

        /* OK */

        return 1;

    }

    return 0;

}

#if 0

static int latmCheck(latm_header *latm, bitfile *ld)

{

    uint32_t good=0, bad=0, bits, m;

    while (ld->bytes_left)

    {

        bits = faad_latm_frame(latm, ld);

        if(bits==0xFFFFFFFF)

            bad++;

        else

        {

            good++;

            while(bits>0)

            {

                m = min(bits, 8);

                faad_getbits(ld, m);

                bits -= m;

            }

        }

    }

    return (good>0);

}

#endif

long NeAACDecInit(NeAACDecHandle hpDecoder,

                              unsigned char *buffer,

                              unsigned long buffer_size,

                              unsigned long *samplerate,

                              unsigned char *channels)

{

    uint32_t bits = 0;

    bitfile ld;

    adif_header adif;

    adts_header adts;

    NeAACDecStruct* hDecoder = (NeAACDecStruct*)hpDecoder;

    if ((hDecoder == NULL) || (samplerate == NULL) || (channels == NULL) || (buffer_size == 0))

        return -1;

    adts.old_format = hDecoder->config.useOldADTSFormat;

    hDecoder->sf_index = get_sr_index(hDecoder->config.defSampleRate);

    hDecoder->object_type = hDecoder->config.defObjectType;

    *samplerate = get_sample_rate(hDecoder->sf_index);

    *channels = 1;

    if (buffer != NULL)

    {

#if 0

        int is_latm;

        latm_header *l = &hDecoder->latm_config;

#endif

        faad_initbits(&ld, buffer, buffer_size);

#if 0

        memset(l, 0, sizeof(latm_header));

        is_latm = latmCheck(l, &ld);

        l->inited = 0;

        l->frameLength = 0;

        faad_rewindbits(&ld);

        if(is_latm && l->ASCbits>0)

        {

            int32_t x;

            hDecoder->latm_header_present = 1;

            x = NeAACDecInit2(hDecoder, l->ASC, (l->ASCbits+7)/8, samplerate, channels);

            if(x!=0)

                hDecoder->latm_header_present = 0;

            return x;

        } else

#endif

        /* Check if an ADIF header is present */

        if ((buffer_size >= 8) && (buffer[0] == 'A') && (buffer[1] == 'D') &&

            (buffer[2] == 'I') && (buffer[3] == 'F'))

        {

            hDecoder->adif_header_present = 1;

            get_adif_header(&adif, &ld);

            faad_byte_align(&ld);

            hDecoder->sf_index = adif.pce[0].sf_index;

            hDecoder->object_type = adif.pce[0].object_type + 1;

            *samplerate = get_sample_rate(hDecoder->sf_index);

            *channels = adif.pce[0].channels;

            memcpy(&(hDecoder->pce), &(adif.pce[0]), sizeof(program_config));

            hDecoder->pce_set = 1;

            bits = bit2byte(faad_get_processed_bits(&ld));

        /* Check if an ADTS header is present */

        } else if (adts_frame(&adts, &ld) == 0) {

            hDecoder->adts_header_present = 1;

            hDecoder->sf_index = adts.sf_index;

            hDecoder->object_type = adts.profile + 1;

            *samplerate = get_sample_rate(hDecoder->sf_index);

            *channels = (adts.channel_configuration > 6) ?

                2 : adts.channel_configuration;

        }

        if (ld.error)

        {

            faad_endbits(&ld);

            return -1;

        }

        faad_endbits(&ld);

    }

    if (!*samplerate)

        return -1;

    hDecoder->channelConfiguration = *channels;

#ifdef SBR_DEC

    /* implicit signalling */

    if (*samplerate <= 24000 && (hDecoder->config.dontUpSampleImplicitSBR == 0))

    {

        *samplerate *= 2;

        hDecoder->forceUpSampling = 1;

    } else if (*samplerate > 24000 && (hDecoder->config.dontUpSampleImplicitSBR == 0)) {

        hDecoder->downSampledSBR = 1;

    }

#endif

    if (can_decode_ot(hDecoder->object_type) < 0)

        return -1;

    /* must be done before frameLength is divided by 2 for LD */

#ifdef SSR_DEC

    if (hDecoder->object_type == SSR)

        hDecoder->fb = ssr_filter_bank_init(hDecoder->frameLength/SSR_BANDS);

    else

#endif

        hDecoder->fb = filter_bank_init(hDecoder->frameLength);

#ifdef LD_DEC

    if (hDecoder->object_type == LD)

        hDecoder->frameLength >>= 1;

#endif

    return bits;

}

/* Init the library using a DecoderSpecificInfo */

char NeAACDecInit2(NeAACDecHandle hpDecoder,

                               unsigned char *pBuffer,

                               unsigned long SizeOfDecoderSpecificInfo,

                               unsigned long *samplerate,

                               unsigned char *channels)

{

    NeAACDecStruct* hDecoder = (NeAACDecStruct*)hpDecoder;

    int8_t rc;

    mp4AudioSpecificConfig mp4ASC;

    if((hDecoder == NULL)

        || (pBuffer == NULL)

        || (SizeOfDecoderSpecificInfo < 2)

        || (samplerate == NULL)

        || (channels == NULL))

    {

        return -1;

    }

    hDecoder->adif_header_present = 0;

    hDecoder->adts_header_present = 0;

    /* decode the audio specific config */

    rc = AudioSpecificConfig2(pBuffer, SizeOfDecoderSpecificInfo, &mp4ASC,

        &(hDecoder->pce), hDecoder->latm_header_present);

    /* copy the relevant info to the decoder handle */

    *samplerate = mp4ASC.samplingFrequency;

    if (mp4ASC.channelsConfiguration)

    {

        *channels = mp4ASC.channelsConfiguration;

    } else {

        *channels = hDecoder->pce.channels;

        hDecoder->pce_set = 1;

    }

#if (defined(PS_DEC) || defined(DRM_PS))

    hDecoder->ps_present_flag = mp4ASC.ps_present_flag;

#endif

    hDecoder->sf_index = mp4ASC.samplingFrequencyIndex;

    hDecoder->object_type = mp4ASC.objectTypeIndex;

#ifdef ERROR_RESILIENCE

    hDecoder->aacSectionDataResilienceFlag = mp4ASC.aacSectionDataResilienceFlag;

    hDecoder->aacScalefactorDataResilienceFlag = mp4ASC.aacScalefactorDataResilienceFlag;

    hDecoder->aacSpectralDataResilienceFlag = mp4ASC.aacSpectralDataResilienceFlag;

#endif

#ifdef SBR_DEC

    hDecoder->sbr_present_flag = mp4ASC.sbr_present_flag;

    hDecoder->downSampledSBR = mp4ASC.downSampledSBR;

    if (hDecoder->config.dontUpSampleImplicitSBR == 0)

        hDecoder->forceUpSampling = mp4ASC.forceUpSampling;

    else

        hDecoder->forceUpSampling = 0;

    /* AAC core decoder samplerate is 2 times as low */

    if (((hDecoder->sbr_present_flag == 1)&&(!hDecoder->downSampledSBR)) || hDecoder->forceUpSampling == 1)

    {

        hDecoder->sf_index = get_sr_index(mp4ASC.samplingFrequency / 2);

    }

#endif

    if (rc != 0)

    {

        return rc;

    }

    hDecoder->channelConfiguration = mp4ASC.channelsConfiguration;

    if (mp4ASC.frameLengthFlag)

#ifdef ALLOW_SMALL_FRAMELENGTH

        hDecoder->frameLength = 960;

#else

        return -1;

#endif

    /* must be done before frameLength is divided by 2 for LD */

#ifdef SSR_DEC

    if (hDecoder->object_type == SSR)

        hDecoder->fb = ssr_filter_bank_init(hDecoder->frameLength/SSR_BANDS);

    else

#endif

        hDecoder->fb = filter_bank_init(hDecoder->frameLength);

#ifdef LD_DEC

    if (hDecoder->object_type == LD)

        hDecoder->frameLength >>= 1;

#endif

    return 0;

}

#ifdef DRM

char NeAACDecInitDRM(NeAACDecHandle *hpDecoder,

                                 unsigned long samplerate,

                                 unsigned char channels)

{

    NeAACDecStruct** hDecoder = (NeAACDecStruct**)hpDecoder;

    if (hDecoder == NULL)

        return 1; /* error */

    NeAACDecClose(*hDecoder);

    *hDecoder = NeAACDecOpen();

    /* Special object type defined for DRM */

    (*hDecoder)->config.defObjectType = DRM_ER_LC;

    (*hDecoder)->config.defSampleRate = samplerate;

#ifdef ERROR_RESILIENCE // This shoudl always be defined for DRM

    (*hDecoder)->aacSectionDataResilienceFlag = 1; /* VCB11 */

    (*hDecoder)->aacScalefactorDataResilienceFlag = 0; /* no RVLC */

    (*hDecoder)->aacSpectralDataResilienceFlag = 1; /* HCR */

#endif

    (*hDecoder)->frameLength = 960;

    (*hDecoder)->sf_index = get_sr_index((*hDecoder)->config.defSampleRate);

    (*hDecoder)->object_type = (*hDecoder)->config.defObjectType;

    if ((channels == DRMCH_STEREO) || (channels == DRMCH_SBR_STEREO))

        (*hDecoder)->channelConfiguration = 2;

    else

        (*hDecoder)->channelConfiguration = 1;

#ifdef SBR_DEC

    if ((channels == DRMCH_MONO) || (channels == DRMCH_STEREO))

        (*hDecoder)->sbr_present_flag = 0;

    else

        (*hDecoder)->sbr_present_flag = 1;

#endif

    (*hDecoder)->fb = filter_bank_init((*hDecoder)->frameLength);

    return 0;

}

#endif

void NeAACDecClose(NeAACDecHandle hpDecoder)

{

    uint8_t i;

    NeAACDecStruct* hDecoder = (NeAACDecStruct*)hpDecoder;

    if (hDecoder == NULL)

        return;

#ifdef PROFILE

    printf("AAC decoder total:  %I64d cycles\n", hDecoder->cycles);

    printf("requant:            %I64d cycles\n", hDecoder->requant_cycles);

    printf("spectral_data:      %I64d cycles\n", hDecoder->spectral_cycles);

    printf("scalefactors:       %I64d cycles\n", hDecoder->scalefac_cycles);

    printf("output:             %I64d cycles\n", hDecoder->output_cycles);

#endif

    for (i = 0; i < MAX_CHANNELS; i++)

    {

        if (hDecoder->time_out[i]) faad_free(hDecoder->time_out[i]);

        if (hDecoder->fb_intermed[i]) faad_free(hDecoder->fb_intermed[i]);

#ifdef SSR_DEC

        if (hDecoder->ssr_overlap[i]) faad_free(hDecoder->ssr_overlap[i]);

        if (hDecoder->prev_fmd[i]) faad_free(hDecoder->prev_fmd[i]);

#endif

#ifdef MAIN_DEC

        if (hDecoder->pred_stat[i]) faad_free(hDecoder->pred_stat[i]);

#endif

#ifdef LTP_DEC

        if (hDecoder->lt_pred_stat[i]) faad_free(hDecoder->lt_pred_stat[i]);

#endif

    }

#ifdef SSR_DEC

    if (hDecoder->object_type == SSR)

        ssr_filter_bank_end(hDecoder->fb);

    else

#endif

        filter_bank_end(hDecoder->fb);

    drc_end(hDecoder->drc);

    if (hDecoder->sample_buffer) faad_free(hDecoder->sample_buffer);

#ifdef SBR_DEC

    for (i = 0; i < MAX_SYNTAX_ELEMENTS; i++)

    {

        if (hDecoder->sbr[i])

            sbrDecodeEnd(hDecoder->sbr[i]);

    }

#endif

    if (hDecoder) faad_free(hDecoder);

}

void NeAACDecPostSeekReset(NeAACDecHandle hpDecoder, long frame)

{

    NeAACDecStruct* hDecoder = (NeAACDecStruct*)hpDecoder;

    if (hDecoder)

    {

        hDecoder->postSeekResetFlag = 1;

        if (frame != -1)

            hDecoder->frame = frame;

    }

}

static void create_channel_config(NeAACDecStruct *hDecoder, NeAACDecFrameInfo *hInfo)

{

    hInfo->num_front_channels = 0;

    hInfo->num_side_channels = 0;

    hInfo->num_back_channels = 0;

    hInfo->num_lfe_channels = 0;

    memset(hInfo->channel_position, 0, MAX_CHANNELS*sizeof(uint8_t));

    if (hDecoder->downMatrix)

    {

        hInfo->num_front_channels = 2;

        hInfo->channel_position[0] = FRONT_CHANNEL_LEFT;

        hInfo->channel_position[1] = FRONT_CHANNEL_RIGHT;

        return;

    }

    /* check if there is a PCE */

    /* TODO: why CPE flag is ignored? */

    if (hDecoder->pce_set)

    {

        uint8_t i, chpos = 0;

        uint8_t chdir, back_center = 0;

        hInfo->num_front_channels = hDecoder->pce.num_front_channels;

        hInfo->num_side_channels = hDecoder->pce.num_side_channels;

        hInfo->num_back_channels = hDecoder->pce.num_back_channels;

        hInfo->num_lfe_channels = hDecoder->pce.num_lfe_channels;

        chdir = hInfo->num_front_channels;

        if (chdir & 1)

        {

#if (defined(PS_DEC) || defined(DRM_PS))

            if (hInfo->num_front_channels == 1 &&

                hInfo->num_side_channels == 0 &&

                hInfo->num_back_channels == 0 &&

                hInfo->num_lfe_channels == 0 &&

                hDecoder->ps_used_global)

            {

                /* When PS is enabled output is always stereo */

                hInfo->channel_position[chpos++] = FRONT_CHANNEL_LEFT;

                hInfo->channel_position[chpos++] = FRONT_CHANNEL_RIGHT;

            } else

#endif

            hInfo->channel_position[chpos++] = FRONT_CHANNEL_CENTER;

            chdir--;

        }

        for (i = 0; i < chdir; i++)

        {

            hInfo->channel_position[chpos++] =

                (i & 1) ? FRONT_CHANNEL_RIGHT : FRONT_CHANNEL_LEFT;

        }

        for (i = 0; i < hInfo->num_side_channels; i++)

        {

            hInfo->channel_position[chpos++] =

                (i & 1) ? SIDE_CHANNEL_RIGHT : SIDE_CHANNEL_LEFT;

        }

        chdir = hInfo->num_back_channels;

        if (chdir & 1)

        {

            back_center = 1;

            chdir--;

        }

        for (i = 0; i < chdir; i++)

        {

            hInfo->channel_position[chpos++] =

                (i & 1) ? BACK_CHANNEL_RIGHT : BACK_CHANNEL_LEFT;

        }

        if (back_center)

        {

            hInfo->channel_position[chpos++] = BACK_CHANNEL_CENTER;

        }

        for (i = 0; i < hInfo->num_lfe_channels; i++)

        {

            hInfo->channel_position[chpos++] = LFE_CHANNEL;

        }

    } else {

        switch (hDecoder->channelConfiguration)

        {

        case 1:

#if (defined(PS_DEC) || defined(DRM_PS))

            if (hDecoder->ps_used_global)

            {

                /* When PS is enabled output is always stereo */

                hInfo->num_front_channels = 2;

                hInfo->channel_position[0] = FRONT_CHANNEL_LEFT;

                hInfo->channel_position[1] = FRONT_CHANNEL_RIGHT;

            } else {

                hInfo->num_front_channels = 1;

                hInfo->channel_position[0] = FRONT_CHANNEL_CENTER;

            }

#else

            hInfo->num_front_channels = 1;

            hInfo->channel_position[0] = FRONT_CHANNEL_CENTER;

#endif

            break;

        case 2:

            hInfo->num_front_channels = 2;

            hInfo->channel_position[0] = FRONT_CHANNEL_LEFT;

            hInfo->channel_position[1] = FRONT_CHANNEL_RIGHT;

            break;

        case 3:

            hInfo->num_front_channels = 3;

            hInfo->channel_position[0] = FRONT_CHANNEL_CENTER;

            hInfo->channel_position[1] = FRONT_CHANNEL_LEFT;

            hInfo->channel_position[2] = FRONT_CHANNEL_RIGHT;

            break;

        case 4:

            hInfo->num_front_channels = 3;

            hInfo->num_back_channels = 1;

            hInfo->channel_position[0] = FRONT_CHANNEL_CENTER;

            hInfo->channel_position[1] = FRONT_CHANNEL_LEFT;

            hInfo->channel_position[2] = FRONT_CHANNEL_RIGHT;

            hInfo->channel_position[3] = BACK_CHANNEL_CENTER;

            break;

        case 5:

            hInfo->num_front_channels = 3;

            hInfo->num_back_channels = 2;

            hInfo->channel_position[0] = FRONT_CHANNEL_CENTER;

            hInfo->channel_position[1] = FRONT_CHANNEL_LEFT;

            hInfo->channel_position[2] = FRONT_CHANNEL_RIGHT;

            hInfo->channel_position[3] = BACK_CHANNEL_LEFT;

            hInfo->channel_position[4] = BACK_CHANNEL_RIGHT;

            break;

        case 6:

            hInfo->num_front_channels = 3;

            hInfo->num_back_channels = 2;

            hInfo->num_lfe_channels = 1;

            hInfo->channel_position[0] = FRONT_CHANNEL_CENTER;

            hInfo->channel_position[1] = FRONT_CHANNEL_LEFT;

            hInfo->channel_position[2] = FRONT_CHANNEL_RIGHT;

            hInfo->channel_position[3] = BACK_CHANNEL_LEFT;

            hInfo->channel_position[4] = BACK_CHANNEL_RIGHT;

            hInfo->channel_position[5] = LFE_CHANNEL;

            break;

        case 7:

            hInfo->num_front_channels = 3;

            hInfo->num_side_channels = 2;

            hInfo->num_back_channels = 2;

            hInfo->num_lfe_channels = 1;

            hInfo->channel_position[0] = FRONT_CHANNEL_CENTER;

            hInfo->channel_position[1] = FRONT_CHANNEL_LEFT;

            hInfo->channel_position[2] = FRONT_CHANNEL_RIGHT;

            hInfo->channel_position[3] = SIDE_CHANNEL_LEFT;

            hInfo->channel_position[4] = SIDE_CHANNEL_RIGHT;

            hInfo->channel_position[5] = BACK_CHANNEL_LEFT;

            hInfo->channel_position[6] = BACK_CHANNEL_RIGHT;

            hInfo->channel_position[7] = LFE_CHANNEL;

            break;

        default: /* channelConfiguration == 0 || channelConfiguration > 7 */

            {

                uint8_t i;

                uint8_t ch = hDecoder->fr_channels - hDecoder->has_lfe;

                if (ch & 1) /* there's either a center front or a center back channel */

                {

                    uint8_t ch1 = (ch-1)/2;

                    if (hDecoder->first_syn_ele == ID_SCE)

                    {

                        hInfo->num_front_channels = ch1 + 1;

                        hInfo->num_back_channels = ch1;

                        hInfo->channel_position[0] = FRONT_CHANNEL_CENTER;

                        for (i = 1; i <= ch1; i+=2)

                        {

                            hInfo->channel_position[i] = FRONT_CHANNEL_LEFT;

                            hInfo->channel_position[i+1] = FRONT_CHANNEL_RIGHT;

                        }

                        for (i = ch1+1; i < ch; i+=2)

                        {

                            hInfo->channel_position[i] = BACK_CHANNEL_LEFT;

                            hInfo->channel_position[i+1] = BACK_CHANNEL_RIGHT;

                        }

                    } else {

                        hInfo->num_front_channels = ch1;

                        hInfo->num_back_channels = ch1 + 1;

                        for (i = 0; i < ch1; i+=2)

                        {

                            hInfo->channel_position[i] = FRONT_CHANNEL_LEFT;

                            hInfo->channel_position[i+1] = FRONT_CHANNEL_RIGHT;

                        }

                        for (i = ch1; i < ch-1; i+=2)

                        {

                            hInfo->channel_position[i] = BACK_CHANNEL_LEFT;

                            hInfo->channel_position[i+1] = BACK_CHANNEL_RIGHT;

                        }

                        hInfo->channel_position[ch-1] = BACK_CHANNEL_CENTER;

                    }

                } else {

                    uint8_t ch1 = (ch)/2;

                    hInfo->num_front_channels = ch1;

                    hInfo->num_back_channels = ch1;

                    if (ch1 & 1)

                    {

                        hInfo->channel_position[0] = FRONT_CHANNEL_CENTER;

                        for (i = 1; i <= ch1; i+=2)

                        {

                            hInfo->channel_position[i] = FRONT_CHANNEL_LEFT;

                            hInfo->channel_position[i+1] = FRONT_CHANNEL_RIGHT;

                        }

                        for (i = ch1+1; i < ch-1; i+=2)

                        {

                            hInfo->channel_position[i] = BACK_CHANNEL_LEFT;

                            hInfo->channel_position[i+1] = BACK_CHANNEL_RIGHT;

                        }

                        hInfo->channel_position[ch-1] = BACK_CHANNEL_CENTER;

                    } else {

                        for (i = 0; i < ch1; i+=2)

                        {

                            hInfo->channel_position[i] = FRONT_CHANNEL_LEFT;

                            hInfo->channel_position[i+1] = FRONT_CHANNEL_RIGHT;

                        }

                        for (i = ch1; i < ch; i+=2)

                        {

                            hInfo->channel_position[i] = BACK_CHANNEL_LEFT;

                            hInfo->channel_position[i+1] = BACK_CHANNEL_RIGHT;

                        }

                    }

                }

                hInfo->num_lfe_channels = hDecoder->has_lfe;

                for (i = ch; i < hDecoder->fr_channels; i++)

                {

                    hInfo->channel_position[i] = LFE_CHANNEL;

                }

            }

            break;

        }

    }

}

void* NeAACDecDecode(NeAACDecHandle hpDecoder,

                                 NeAACDecFrameInfo *hInfo,

                                 unsigned char *buffer,

                                 unsigned long buffer_size)

{

    NeAACDecStruct* hDecoder = (NeAACDecStruct*)hpDecoder;

    return aac_frame_decode(hDecoder, hInfo, buffer, buffer_size, NULL, 0);

}

void* NeAACDecDecode2(NeAACDecHandle hpDecoder,

                                  NeAACDecFrameInfo *hInfo,

                                  unsigned char *buffer,

                                  unsigned long buffer_size,

                                  void **sample_buffer,

                                  unsigned long sample_buffer_size)

{

    NeAACDecStruct* hDecoder = (NeAACDecStruct*)hpDecoder;

    if ((sample_buffer_size == 0) || (sample_buffer == NULL) || (*sample_buffer == NULL))

    {

        hInfo->error = 27;

        return NULL;

    }

    return aac_frame_decode(hDecoder, hInfo, buffer, buffer_size,

        sample_buffer, sample_buffer_size);

}

static void* aac_frame_decode(NeAACDecStruct *hDecoder,

                              NeAACDecFrameInfo *hInfo,

                              unsigned char *buffer,

                              unsigned long buffer_size,

                              void **sample_buffer2,

                              unsigned long sample_buffer_size)

{

    uint16_t i;

    uint8_t channels = 0;

    uint8_t output_channels = 0;

    bitfile ld;

    uint32_t bitsconsumed;

    uint16_t frame_len;

    void *sample_buffer;

#if 0

    uint32_t startbit=0, endbit=0, payload_bits=0;

#endif

    uint32_t required_buffer_size=0;

#ifdef PROFILE

    int64_t count = faad_get_ts();

#endif

    /* safety checks */

    if ((hDecoder == NULL) || (hInfo == NULL) || (buffer == NULL))

    {

        return NULL;

    }

#if 0

    printf("%d\n", buffer_size*8);

#endif

    frame_len = hDecoder->frameLength;

    memset(hInfo, 0, sizeof(NeAACDecFrameInfo));

    memset(hDecoder->internal_channel, 0, MAX_CHANNELS*sizeof(hDecoder->internal_channel[0]));

#ifdef USE_TIME_LIMIT

    if ((TIME_LIMIT * get_sample_rate(hDecoder->sf_index)) > hDecoder->TL_count)

    {

        hDecoder->TL_count += 1024;

    } else {

        hInfo->error = (NUM_ERROR_MESSAGES-1);

        goto error;

    }

#endif

    /* check for some common metadata tag types in the bitstream

     * No need to return an error

     */

    /* ID3 */

    if (buffer_size >= 128)

    {

        if (memcmp(buffer, "TAG", 3) == 0)

        {

            /* found it */

            hInfo->bytesconsumed = 128; /* 128 bytes fixed size */

            /* no error, but no output either */

            return NULL;

        }

    }