shithub: aacdec

ref: f116386606467fb4563610b5d8bc4fcea2f2211c
dir: /libfaad/decoder.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: decoder.c,v 1.6 2002/01/20 16:57:55 menno Exp $
**/

#include <stdlib.h>
#include <memory.h>
#include "decoder.h"
#include "mp4.h"
#include "syntax.h"
#include "specrec.h"
#include "data.h"
#include "tns.h"
#include "pns.h"
#include "is.h"
#include "ms.h"
#include "ic_predict.h"
#include "lt_predict.h"
#include "drc.h"
#include "error.h"
#include "output.h"

#ifdef ANALYSIS
int dbg_count;
#endif

char* FAADAPI faacDecGetErrorMessage(int errcode)
{
    return err_msg[errcode];
}

faacDecHandle FAADAPI faacDecOpen()
{
    int i;
    faacDecHandle hDecoder = NULL;

    if ((hDecoder = (faacDecHandle)malloc(sizeof(faacDecStruct))) == NULL)
        return NULL;

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

    hDecoder->config.outputFormat  = FAAD_FMT_16BIT;
    hDecoder->config.defObjectType = MAIN;
    hDecoder->config.defSampleRate = 44100; /* Default: 44.1kHz */
    hDecoder->adts_header_present = 0;
    hDecoder->adif_header_present = 0;

    hDecoder->frame = 0;
    hDecoder->sample_buffer = NULL;

    for (i = 0; i < MAX_CHANNELS; i++)
    {
        hDecoder->window_shape_prev[i] = 0;
        hDecoder->time_state[i] = NULL;
        hDecoder->time_out[i] = NULL;
        hDecoder->pred_stat[i] = NULL;
        hDecoder->lt_pred_stat[i] = NULL;
    }

    init_drc(&hDecoder->drc, 1.0f, 1.0f);
    filter_bank_init(&hDecoder->fb);
#if IQ_TABLE_SIZE && POW_TABLE_SIZE
    build_tables(hDecoder->iq_table, hDecoder->pow2_table);
#elif !IQ_TABLE_SIZE && POW_TABLE_SIZE
    build_tables(NULL, hDecoder->pow2_table);
#elif IQ_TABLE_SIZE && !POW_TABLE_SIZE
    build_tables(hDecoder->iq_table, NULL);
#endif

    return hDecoder;
}

faacDecConfigurationPtr FAADAPI faacDecGetCurrentConfiguration(faacDecHandle hDecoder)
{
    faacDecConfigurationPtr config = &(hDecoder->config);

    return config;
}

int FAADAPI faacDecSetConfiguration(faacDecHandle hDecoder,
                                    faacDecConfigurationPtr config)
{
    hDecoder->config.defObjectType = config->defObjectType;
    hDecoder->config.defSampleRate = config->defSampleRate;
    hDecoder->config.outputFormat  = config->outputFormat;

    /* OK */
    return 1;
}

/* Returns the sample rate index */
static int get_sr_index(unsigned long samplerate)
{
    if (92017 <= samplerate) return 0;
    if (75132 <= samplerate) return 1;
    if (55426 <= samplerate) return 2;
    if (46009 <= samplerate) return 3;
    if (37566 <= samplerate) return 4;
    if (27713 <= samplerate) return 5;
    if (23004 <= samplerate) return 6;
    if (18783 <= samplerate) return 7;
    if (13856 <= samplerate) return 8;
    if (11502 <= samplerate) return 9;
    if (9391 <= samplerate) return 10;

    return 11;
}

int FAADAPI faacDecInit(faacDecHandle hDecoder, unsigned char *buffer,
                        unsigned long *samplerate, unsigned long *channels)
{
    bitfile ld;
    adif_header adif;
    adts_header adts;

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

    if (buffer != NULL)
    {
        faad_initbits(&ld, buffer);

        /* Check if an ADIF header is present */
        if ((buffer[0] == 'A') && (buffer[1] == 'D') &&
            (buffer[2] == 'I') && (buffer[3] == 'F'))
        {
            hDecoder->adif_header_present = 1;

            get_adif_header(&adif, &ld);

            hDecoder->sf_index = adif.pce.sf_index;
            hDecoder->object_type = adif.pce.object_type;

            *samplerate = sample_rates[hDecoder->sf_index];
            *channels = adif.pce.channels;

            return bit2byte(faad_get_processed_bits(&ld));

        /* Check if an ADTS header is present */
        } else if (faad_showbits(&ld, 12) == 0xfff) {
            hDecoder->adts_header_present = 1;

            adts_frame(&adts, &ld);

            hDecoder->sf_index = adts.sf_index;
            hDecoder->object_type = adts.profile;

            *samplerate = sample_rates[hDecoder->sf_index];
            *channels = (adts.channel_configuration > 6) ?
                2 : adts.channel_configuration;

            return 0;
        }
    }

    *samplerate = sample_rates[hDecoder->sf_index];
    *channels = 2;

    return 0;
}

/* Init the library using a DecoderSpecificInfo */
int FAADAPI faacDecInit2(faacDecHandle hDecoder, unsigned char *pBuffer,
                         unsigned long SizeOfDecoderSpecificInfo,
                         unsigned long *samplerate, unsigned long *channels)
{
    int rc;

    hDecoder->adif_header_present = 0;
    hDecoder->adts_header_present = 0;

    if((hDecoder == NULL)
        || (pBuffer == NULL)
        || (SizeOfDecoderSpecificInfo < 2)
        || (samplerate == NULL)
        || (channels == NULL))
    {
        return -1;
    }

    rc = AudioSpecificConfig(pBuffer, samplerate, channels,
        &hDecoder->sf_index, &hDecoder->object_type);
    hDecoder->object_type--; /* For AAC differs from MPEG-4 */
    if (rc != 0)
    {
        return rc;
    }

    return 0;
}

void FAADAPI faacDecClose(faacDecHandle hDecoder)
{
    int i;

    for (i = 0; i < MAX_CHANNELS; i++)
    {
        if (hDecoder->time_state[i]) free(hDecoder->time_state[i]);
        if (hDecoder->time_out[i]) free(hDecoder->time_out[i]);
        if (hDecoder->pred_stat[i]) free(hDecoder->pred_stat[i]);
        if (hDecoder->lt_pred_stat[i]) free(hDecoder->lt_pred_stat[i]);
    }

    filter_bank_end(&hDecoder->fb);

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

    if (hDecoder) free(hDecoder);
}

void* FAADAPI faacDecDecode(faacDecHandle hDecoder,
                            faacDecFrameInfo *hInfo,
                            unsigned char *buffer)
{
    int id_syn_ele, ele, ch, i;
    adts_header adts;
    int channels, ch_ele;
    bitfile *ld = malloc(sizeof(bitfile));

    /* local copys of globals */
    int sf_index           =  hDecoder->sf_index;
    int object_type        =  hDecoder->object_type;
    pred_state **pred_stat =  hDecoder->pred_stat;
    float **lt_pred_stat   =  hDecoder->lt_pred_stat;
#if IQ_TABLE_SIZE
    float *iq_table        =  hDecoder->iq_table;
#else
    float *iq_table        =  NULL;
#endif
#if POW_TABLE_SIZE
    float *pow2_table      =  hDecoder->pow2_table;
#else
    float *pow2_table      =  NULL;
#endif
    int *window_shape_prev =  hDecoder->window_shape_prev;
    float **time_state     =  hDecoder->time_state;
    float **time_out       =  hDecoder->time_out;
    fb_info *fb            = &hDecoder->fb;
    drc_info *drc          = &hDecoder->drc;
    int outputFormat       =  hDecoder->config.outputFormat;

    program_config pce;
    element *syntax_elements[MAX_SYNTAX_ELEMENTS];
    short *spec_data[MAX_CHANNELS];
    float *spec_coef[MAX_CHANNELS];

    void *sample_buffer;

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

    /* initialize the bitstream */
    faad_initbits(ld, buffer);

    if (hDecoder->adts_header_present)
    {
        if ((hInfo->error = adts_frame(&adts, ld)) > 0)
            goto error;

        /* MPEG2 does byte_alignment() here,
         * but ADTS header is always multiple of 8 bits in MPEG2
         * so not needed to actually do it.
         */
    }

    ele = 0;
    channels = 0;
    ch_ele = 0;

#ifdef ANALYSIS
    dbg_count = 0;
#endif

    /* Table 4.4.3: raw_data_block() */
    while ((id_syn_ele = 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:
            spec_data[channels]   = (short*)malloc(1024*sizeof(short));
            spec_coef[channels]   = (float*)malloc(1024*sizeof(float));

            syntax_elements[ch_ele] = (element*)malloc(sizeof(element));
            memset(syntax_elements[ch_ele], 0, sizeof(element));
            syntax_elements[ch_ele]->ele_id  = id_syn_ele;
            syntax_elements[ch_ele]->channel = channels;

            if ((hInfo->error = single_lfe_channel_element(syntax_elements[ch_ele],
                ld, spec_data[channels], sf_index, object_type)) > 0)
            {
                /* to make sure everything gets deallocated */
                channels++; ch_ele++;
                goto error;
            }

            channels++;
            ch_ele++;
            break;
        case ID_CPE:
            spec_data[channels]   = (short*)malloc(1024*sizeof(short));
            spec_data[channels+1] = (short*)malloc(1024*sizeof(short));
            spec_coef[channels]   = (float*)malloc(1024*sizeof(float));
            spec_coef[channels+1] = (float*)malloc(1024*sizeof(float));

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

            if ((hInfo->error = channel_pair_element(syntax_elements[ch_ele],
                ld, spec_data[channels], spec_data[channels+1],
                sf_index, object_type)) > 0)
            {
                /* to make sure everything gets deallocated */
                channels+=2; ch_ele++;
                goto error;
            }

            channels += 2;
            ch_ele++;
            break;
        case ID_CCE: /* not implemented yet */
            hInfo->error = 6;
            goto error;
            break;
        case ID_DSE:
            data_stream_element(ld);
            break;
        case ID_PCE:
            if ((hInfo->error = program_config_element(&pce, ld)) > 0)
                goto error;
            break;
        case ID_FIL:
            if ((hInfo->error = fill_element(ld, drc)) > 0)
                goto error;
            break;
        }
        ele++;
    }
    /* no more bit reading after this */
    faad_byte_align(ld);
    hInfo->bytesconsumed = bit2byte(faad_get_processed_bits(ld));
    if (ld) free(ld);
    ld = NULL;

    /* number of samples in this frame */
    hInfo->samples = 1024*channels;
    /* number of samples in this frame */
    hInfo->channels = channels;

    if (hDecoder->sample_buffer == NULL)
        hDecoder->sample_buffer = malloc(1024*channels*sizeof(float));

    sample_buffer = hDecoder->sample_buffer;

    /* noiseless coding is done, the rest of the tools come now */
    for (ch = 0; ch < channels; ch++)
    {
        ic_stream *ics;

        /* find the syntax element to which this channel belongs */
        for (i = 0; i < ch_ele; i++)
        {
            if (syntax_elements[i]->channel == ch)
            {
                ics = &syntax_elements[i]->ics1;
                break;
            } else if (syntax_elements[i]->paired_channel == ch) {
                ics = &syntax_elements[i]->ics2;
                break;
            }
        }

        /* inverse quantization */
        inverse_quantization(spec_coef[ch], spec_data[ch], iq_table);

        /* apply scalefactors */
        apply_scalefactors(ics, spec_coef[ch], pow2_table);

        /* deinterleave short block grouping */
        if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
            quant_to_spec(ics, spec_coef[ch]);
    }

    /* Because for ms and is both channels spectral coefficients are needed
       we have to restart running through all channels here.
    */
    for (ch = 0; ch < channels; ch++)
    {
        int pch = 0;
        int right_channel;
        ic_stream *ics, *icsr;
        ltp_info *ltp;

        /* find the syntax element to which this channel belongs */
        for (i = 0; i < ch_ele; i++)
        {
            if (syntax_elements[i]->channel == ch)
            {
                ics = &syntax_elements[i]->ics1;
                icsr = &syntax_elements[i]->ics2;
                ltp = &(ics->ltp);
                pch = syntax_elements[i]->paired_channel;
                right_channel = 0;
                break;
            } else if (syntax_elements[i]->paired_channel == ch) {
                ics = &syntax_elements[i]->ics2;
                ltp = &(ics->ltp2);
                right_channel = 1;
                break;
            }
        }

        /* mid/side decoding */
        if (!right_channel)
            ms_decode(ics, icsr, spec_coef[ch], spec_coef[pch]);

        /* pns decoding */
        pns_decode(ics, spec_coef[ch]);

        /* intensity stereo decoding */
        if (!right_channel)
            is_decode(ics, icsr, spec_coef[ch], spec_coef[pch]);

        /* MAIN object type prediction */
        if (object_type == MAIN)
        {
            /* allocate the state only when needed */
            if ((pred_stat[ch] == NULL) && ics->predictor_data_present)
            {
                pred_stat[ch] = malloc(1024 * sizeof(pred_state));
                reset_all_predictors(pred_stat[ch]);
            }

            /* intra channel prediction */
            if (pred_stat[ch] != NULL)
            {
                ic_prediction(ics, spec_coef[ch], pred_stat[ch]);

                /* In addition, for scalefactor bands coded by perceptual
                   noise substitution the predictors belonging to the
                   corresponding spectral coefficients are reset.
                 */
                pns_reset_pred_state(ics, pred_stat[ch]);
            }
        } else if (object_type == LTP) {
            /* allocate the state only when needed */
            if ((lt_pred_stat[ch] == NULL) && ics->predictor_data_present)
            {
                lt_pred_stat[ch] = malloc(1024*3 * sizeof(float));
                memset(lt_pred_stat[ch], 0, 1024*3 * sizeof(float));
            }

            /* long term prediction */
            if (lt_pred_stat[ch] != NULL)
            {
                lt_prediction(ics, ltp, spec_coef[ch], lt_pred_stat[ch], fb,
                    ics->window_shape, window_shape_prev[ch],
                    sf_index, object_type);
            }
        }

        /* tns decoding */
        tns_decode_frame(ics, &ics->tns, sf_index, object_type, spec_coef[ch]);

        /* drc decoding */
        if (drc->present)
        {
            if (!drc->exclude_mask[ch] || !drc->excluded_chns_present)
                drc_decode(drc, spec_coef[ch]);
        }

        if (time_state[ch] == NULL)
        {
            float *tp;

            time_state[ch] = malloc(1024*sizeof(float));
            tp = time_state[ch];
            for (i = 1024/16-1; i >= 0; --i)
            {
                *tp++ = 0; *tp++ = 0; *tp++ = 0; *tp++ = 0;
                *tp++ = 0; *tp++ = 0; *tp++ = 0; *tp++ = 0;
                *tp++ = 0; *tp++ = 0; *tp++ = 0; *tp++ = 0;
                *tp++ = 0; *tp++ = 0; *tp++ = 0; *tp++ = 0;
            }
        }
        if (time_out[ch] == NULL)
        {
            time_out[ch] = malloc(1024*2*sizeof(float));
        }

        /* filter bank */
        ifilter_bank(fb, ics->window_sequence, ics->window_shape,
            window_shape_prev[ch], spec_coef[ch], time_state[ch],
            time_out[ch]);
        /* save window shape for next frame */
        window_shape_prev[ch] = ics->window_shape;

        if ((object_type == LTP) && (lt_pred_stat[ch] != NULL))
            lt_update_state(lt_pred_stat[ch], time_out[ch], time_state[ch]);
    }

    sample_buffer = output_to_PCM(time_out, sample_buffer, channels,
        outputFormat);

    hDecoder->frame++;
    if (hDecoder->frame <= 1)
        hInfo->samples = 0;

    /* cleanup */
    for (ch = 0; ch < channels; ch++)
    {
        free(spec_coef[ch]);
        free(spec_data[ch]);
    }

    for (i = 0; i < ch_ele; i++)
    {
        free(syntax_elements[i]);
    }

#ifdef ANALYSIS
    fflush(stdout);
#endif

    return sample_buffer;

error:
    /* free all memory that could have been allocated */
    if (ld) free(ld);

    /* cleanup */
    for (ch = 0; ch < channels; ch++)
    {
        free(spec_coef[ch]);
        free(spec_data[ch]);
    }

    for (i = 0; i < ch_ele; i++)
    {
        free(syntax_elements[i]);
    }

#ifdef ANALYSIS
    fflush(stdout);
#endif

    return NULL;
}