filtbank.c

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/************************* MPEG-2 NBC Audio Decoder **************************
 *                                                                           *
"This software module was originally developed by
AT&T, Dolby Laboratories, Fraunhofer Gesellschaft IIS in the course of
development of the MPEG-2 NBC/MPEG-4 Audio standard ISO/IEC 13818-7,
14496-1,2 and 3. This software module is an implementation of a part of one or more
MPEG-2 NBC/MPEG-4 Audio tools as specified by the MPEG-2 NBC/MPEG-4
Audio standard. ISO/IEC  gives users of the MPEG-2 NBC/MPEG-4 Audio
standards free license to this software module or modifications thereof for use in
hardware or software products claiming conformance to the MPEG-2 NBC/MPEG-4
Audio  standards. Those intending to use this software module in hardware or
software products are advised that this use may infringe existing patents.
The original developer of this software module and his/her company, the subsequent
editors and their companies, and ISO/IEC have no liability for use of this software
module or modifications thereof in an implementation. Copyright is not released for
non MPEG-2 NBC/MPEG-4 Audio conforming products.The original developer
retains full right to use the code for his/her  own purpose, assign or donate the
code to a third party and to inhibit third party from using the code for non
MPEG-2 NBC/MPEG-4 Audio conforming products. This copyright notice must
be included in all copies or derivative works."
Copyright(c)1996.
 *                                                                           *
 ****************************************************************************/
/*
 * $Id: filtbank.c,v 1.13 2005/02/02 07:51:12 sur Exp $
 */

/*
 * CHANGES:
 *  2001/01/17: menno: Added frequency cut off filter.
 *
 */

#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#include "coder.h"
#include "filtbank.h"
#include "frame.h"
#include "fft.h"
#include "util.h"

#define  TWOPI       2*M_PI


static void		CalculateKBDWindow	( double* win, double alpha, int length );
static double	Izero				( double x);
static void		MDCT				( FFT_Tables *fft_tables, double *data, int N );
static void		IMDCT				( FFT_Tables *fft_tables, double *data, int N );



void FilterBankInit(faacEncHandle hEncoder)
{
    unsigned int i, channel;

    for (channel = 0; channel < hEncoder->numChannels; channel++) {
        hEncoder->freqBuff[channel] = (double*)AllocMemory(2*FRAME_LEN*sizeof(double));
        hEncoder->overlapBuff[channel] = (double*)AllocMemory(FRAME_LEN*sizeof(double));
        SetMemory(hEncoder->overlapBuff[channel], 0, FRAME_LEN*sizeof(double));
    }

    hEncoder->sin_window_long = (double*)AllocMemory(BLOCK_LEN_LONG*sizeof(double));
    hEncoder->sin_window_short = (double*)AllocMemory(BLOCK_LEN_SHORT*sizeof(double));
    hEncoder->kbd_window_long = (double*)AllocMemory(BLOCK_LEN_LONG*sizeof(double));
    hEncoder->kbd_window_short = (double*)AllocMemory(BLOCK_LEN_SHORT*sizeof(double));

    for( i=0; i<BLOCK_LEN_LONG; i++ )
        hEncoder->sin_window_long[i] = sin((M_PI/(2*BLOCK_LEN_LONG)) * (i + 0.5));
    for( i=0; i<BLOCK_LEN_SHORT; i++ )
        hEncoder->sin_window_short[i] = sin((M_PI/(2*BLOCK_LEN_SHORT)) * (i + 0.5));

    CalculateKBDWindow(hEncoder->kbd_window_long, 4, BLOCK_LEN_LONG*2);
    CalculateKBDWindow(hEncoder->kbd_window_short, 6, BLOCK_LEN_SHORT*2);
}

void FilterBankEnd(faacEncHandle hEncoder)
{
    unsigned int channel;

    for (channel = 0; channel < hEncoder->numChannels; channel++) {
        if (hEncoder->freqBuff[channel]) FreeMemory(hEncoder->freqBuff[channel]);
        if (hEncoder->overlapBuff[channel]) FreeMemory(hEncoder->overlapBuff[channel]);
    }

    if (hEncoder->sin_window_long) FreeMemory(hEncoder->sin_window_long);
    if (hEncoder->sin_window_short) FreeMemory(hEncoder->sin_window_short);
    if (hEncoder->kbd_window_long) FreeMemory(hEncoder->kbd_window_long);
    if (hEncoder->kbd_window_short) FreeMemory(hEncoder->kbd_window_short);
}

void FilterBank(faacEncHandle hEncoder,
                CoderInfo *coderInfo,
                double *p_in_data,
                double *p_out_mdct,
                double *p_overlap,
                int overlap_select)
{
    double *p_o_buf, *first_window, *second_window;
    double *transf_buf;
    int k, i;
    int block_type = coderInfo->block_type;

    transf_buf = (double*)AllocMemory(2*BLOCK_LEN_LONG*sizeof(double));

    /* create / shift old values */
    /* We use p_overlap here as buffer holding the last frame time signal*/
    if(overlap_select != MNON_OVERLAPPED) {
        memcpy(transf_buf, p_overlap, FRAME_LEN*sizeof(double));
        memcpy(transf_buf+BLOCK_LEN_LONG, p_in_data, FRAME_LEN*sizeof(double));
        memcpy(p_overlap, p_in_data, FRAME_LEN*sizeof(double));
    } else {
        memcpy(transf_buf, p_in_data, 2*FRAME_LEN*sizeof(double));
    }

    /*  Window shape processing */
    if(overlap_select != MNON_OVERLAPPED) {
        switch (coderInfo->prev_window_shape) {
        case SINE_WINDOW:
            if ( (block_type == ONLY_LONG_WINDOW) || (block_type == LONG_SHORT_WINDOW))
                first_window = hEncoder->sin_window_long;
            else
                first_window = hEncoder->sin_window_short;
            break;
        case KBD_WINDOW:
            if ( (block_type == ONLY_LONG_WINDOW) || (block_type == LONG_SHORT_WINDOW))
                first_window = hEncoder->kbd_window_long;
            else
                first_window = hEncoder->kbd_window_short;
            break;
        }

        switch (coderInfo->window_shape){
        case SINE_WINDOW:
            if ( (block_type == ONLY_LONG_WINDOW) || (block_type == SHORT_LONG_WINDOW))
                second_window = hEncoder->sin_window_long;
            else
                second_window = hEncoder->sin_window_short;
            break;
        case KBD_WINDOW:
            if ( (block_type == ONLY_LONG_WINDOW) || (block_type == SHORT_LONG_WINDOW))
                second_window = hEncoder->kbd_window_long;
            else
                second_window = hEncoder->kbd_window_short;
            break;
        }
    } else {
        /* Always long block and sine window for LTP */
        first_window = hEncoder->sin_window_long;
        second_window = hEncoder->sin_window_long;
    }

    /* Set ptr to transf-Buffer */
    p_o_buf = transf_buf;

    /* Separate action for each Block Type */
    switch (block_type) {
    case ONLY_LONG_WINDOW :
        for ( i = 0 ; i < BLOCK_LEN_LONG ; i++){
            p_out_mdct[i] = p_o_buf[i] * first_window[i];
            p_out_mdct[i+BLOCK_LEN_LONG] = p_o_buf[i+BLOCK_LEN_LONG] * second_window[BLOCK_LEN_LONG-i-1];
        }
        MDCT( &hEncoder->fft_tables, p_out_mdct, 2*BLOCK_LEN_LONG );
        break;

    case LONG_SHORT_WINDOW :
        for ( i = 0 ; i < BLOCK_LEN_LONG ; i++)
            p_out_mdct[i] = p_o_buf[i] * first_window[i];
        memcpy(p_out_mdct+BLOCK_LEN_LONG,p_o_buf+BLOCK_LEN_LONG,NFLAT_LS*sizeof(double));
        for ( i = 0 ; i < BLOCK_LEN_SHORT ; i++)
            p_out_mdct[i+BLOCK_LEN_LONG+NFLAT_LS] = p_o_buf[i+BLOCK_LEN_LONG+NFLAT_LS] * second_window[BLOCK_LEN_SHORT-i-1];
        SetMemory(p_out_mdct+BLOCK_LEN_LONG+NFLAT_LS+BLOCK_LEN_SHORT,0,NFLAT_LS*sizeof(double));
        MDCT( &hEncoder->fft_tables, p_out_mdct, 2*BLOCK_LEN_LONG );
        break;

    case SHORT_LONG_WINDOW :
        SetMemory(p_out_mdct,0,NFLAT_LS*sizeof(double));
        for ( i = 0 ; i < BLOCK_LEN_SHORT ; i++)
            p_out_mdct[i+NFLAT_LS] = p_o_buf[i+NFLAT_LS] * first_window[i];
        memcpy(p_out_mdct+NFLAT_LS+BLOCK_LEN_SHORT,p_o_buf+NFLAT_LS+BLOCK_LEN_SHORT,NFLAT_LS*sizeof(double));
        for ( i = 0 ; i < BLOCK_LEN_LONG ; i++)
            p_out_mdct[i+BLOCK_LEN_LONG] = p_o_buf[i+BLOCK_LEN_LONG] * second_window[BLOCK_LEN_LONG-i-1];
        MDCT( &hEncoder->fft_tables, p_out_mdct, 2*BLOCK_LEN_LONG );
        break;

    case ONLY_SHORT_WINDOW :
        p_o_buf += NFLAT_LS;
        for ( k=0; k < MAX_SHORT_WINDOWS; k++ ) {
            for ( i = 0 ; i < BLOCK_LEN_SHORT ; i++ ){
                p_out_mdct[i] = p_o_buf[i] * first_window[i];
                p_out_mdct[i+BLOCK_LEN_SHORT] = p_o_buf[i+BLOCK_LEN_SHORT] * second_window[BLOCK_LEN_SHORT-i-1];
            }
            MDCT( &hEncoder->fft_tables, p_out_mdct, 2*BLOCK_LEN_SHORT );
            p_out_mdct += BLOCK_LEN_SHORT;
            p_o_buf += BLOCK_LEN_SHORT;
            first_window = second_window;
        }
        break;
    }

    if (transf_buf) FreeMemory(transf_buf);
}

void IFilterBank(faacEncHandle hEncoder,
                 CoderInfo *coderInfo,
                 double *p_in_data,
                 double *p_out_data,
                 double *p_overlap,
                 int overlap_select)
{
    double *o_buf, *transf_buf, *overlap_buf;
    double *first_window, *second_window;

    double  *fp;
    int k, i;
    int block_type = coderInfo->block_type;

    transf_buf = (double*)AllocMemory(2*BLOCK_LEN_LONG*sizeof(double));
    overlap_buf = (double*)AllocMemory(2*BLOCK_LEN_LONG*sizeof(double));

    /*  Window shape processing */
    if (overlap_select != MNON_OVERLAPPED) {
//      switch (coderInfo->prev_window_shape){
//      case SINE_WINDOW:
            if ( (block_type == ONLY_LONG_WINDOW) || (block_type == LONG_SHORT_WINDOW))
                first_window = hEncoder->sin_window_long;
            else
                first_window = hEncoder->sin_window_short;
//          break;
//      case KBD_WINDOW:
//          if ( (block_type == ONLY_LONG_WINDOW) || (block_type == LONG_SHORT_WINDOW))
//              first_window = hEncoder->kbd_window_long;
//          else
//              first_window = hEncoder->kbd_window_short;
//          break;
//      }

//      switch (coderInfo->window_shape){
//      case SINE_WINDOW:
            if ( (block_type == ONLY_LONG_WINDOW) || (block_type == SHORT_LONG_WINDOW))
                second_window = hEncoder->sin_window_long;
            else
                second_window = hEncoder->sin_window_short;
//          break;
//      case KBD_WINDOW:
//          if ( (block_type == ONLY_LONG_WINDOW) || (block_type == SHORT_LONG_WINDOW))
//              second_window = hEncoder->kbd_window_long;
//          else
//              second_window = hEncoder->kbd_window_short;
//          break;
//      }
    } else {
        /* Always long block and sine window for LTP */
        first_window  = hEncoder->sin_window_long;
        second_window = hEncoder->sin_window_long;
    }

    /* Assemble overlap buffer */
    memcpy(overlap_buf,p_overlap,BLOCK_LEN_LONG*sizeof(double));
    o_buf = overlap_buf;

    /* Separate action for each Block Type */
    switch( block_type ) {
    case ONLY_LONG_WINDOW :
        memcpy(transf_buf, p_in_data,BLOCK_LEN_LONG*sizeof(double));
        IMDCT( &hEncoder->fft_tables, transf_buf, 2*BLOCK_LEN_LONG );
        for ( i = 0 ; i < BLOCK_LEN_LONG ; i++)
            transf_buf[i] *= first_window[i];
        if (overlap_select != MNON_OVERLAPPED) {
            for ( i = 0 ; i < BLOCK_LEN_LONG; i++ ){
                o_buf[i] += transf_buf[i];
                o_buf[i+BLOCK_LEN_LONG] = transf_buf[i+BLOCK_LEN_LONG] * second_window[BLOCK_LEN_LONG-i-1];
            }
        } else { /* overlap_select == NON_OVERLAPPED */
            for ( i = 0 ; i < BLOCK_LEN_LONG; i++ )
                transf_buf[i+BLOCK_LEN_LONG] *= second_window[BLOCK_LEN_LONG-i-1];
        }
        break;

    case LONG_SHORT_WINDOW :
        memcpy(transf_buf, p_in_data,BLOCK_LEN_LONG*sizeof(double));
        IMDCT( &hEncoder->fft_tables, transf_buf, 2*BLOCK_LEN_LONG );
        for ( i = 0 ; i < BLOCK_LEN_LONG ; i++)
            transf_buf[i] *= first_window[i];
        if (overlap_select != MNON_OVERLAPPED) {
            for ( i = 0 ; i < BLOCK_LEN_LONG; i++ )
                o_buf[i] += transf_buf[i];
            memcpy(o_buf+BLOCK_LEN_LONG,transf_buf+BLOCK_LEN_LONG,NFLAT_LS*sizeof(double));
            for ( i = 0 ; i < BLOCK_LEN_SHORT ; i++)