fft.c

来自「faac-1.25.rar音频编解码器demo」· C语言 代码 · 共 705 行 · 第 1/2 页

/*
 * FAAC - Freeware Advanced Audio Coder
 * $Id: fft.c,v 1.12 2005/02/02 07:49:55 sur Exp $
 * Copyright (C) 2002 Krzysztof Nikiel
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.

 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

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

#include "fft.h"
#include "util.h"

#define MAXLOGM 9
#define MAXLOGR 8

#if defined DRM && !defined DRM_1024

#include "kiss_fft/kiss_fft.h"
#include "kiss_fft/kiss_fftr.h"

static const int logm_to_nfft[] = 
{
/*  0       1       2       3       */
    0,      0,      0,      0,
/*  4       5       6       7       */
    0,      0,      60,     0,
/*  8       9                       */
    240,    480
};

void fft_initialize( FFT_Tables *fft_tables )
{
    memset( fft_tables->cfg, 0, sizeof( fft_tables->cfg ) );
}
void fft_terminate( FFT_Tables *fft_tables )
{
    unsigned int i;
    for ( i = 0; i < sizeof( fft_tables->cfg ) / sizeof( fft_tables->cfg[0] ); i++ )
    {
        if ( fft_tables->cfg[i][0] )
        {
            free( fft_tables->cfg[i][0] );
            fft_tables->cfg[i][0] = NULL;
        }
        if ( fft_tables->cfg[i][1] )
        {
            free( fft_tables->cfg[i][1] );
            fft_tables->cfg[i][1] = NULL;
        }
    }
}

void rfft( FFT_Tables *fft_tables, double *x, int logm )
{
#if 0
/* sur: do not use real-only optimized FFT */
    double xi[1 << MAXLOGR];

    int nfft;

    if ( logm > MAXLOGR )
	{
		fprintf(stderr, "rfft size too big\n");
		exit(1);
	}

    nfft = logm_to_nfft[logm];

    if ( nfft )
    {
        //unsigned int i;
        //for ( i = 0; i < nfft; i++ )
        //{
        //    xi[i] = 0.0;
        //}
	    memset( xi, 0, nfft * sizeof( xi[0] ) );

	    fft( fft_tables, x, xi, logm );

	    memcpy( x + nfft / 2, xi, ( nfft / 2 ) * sizeof(x[0]) );
    }
    else
    {
        fprintf( stderr, "bad config for logm = %d\n", logm);
        exit( 1 );
    }

#else
/* sur: use real-only optimized FFT */

    int nfft = 0;

    kiss_fft_scalar fin[1 << MAXLOGR];
    kiss_fft_cpx    fout[1 << MAXLOGR];

    if ( logm > MAXLOGR )
	{
		fprintf(stderr, "fft size too big\n");
		exit(1);
	}

    nfft = logm_to_nfft[logm];

    if ( fft_tables->cfg[logm][0] == NULL )
    {
        if ( nfft )
        {
            fft_tables->cfg[logm][0] = kiss_fftr_alloc( nfft, 0, NULL, NULL );
        }
        else
        {
	    	fprintf(stderr, "bad logm = %d\n", logm);
            exit( 1 );
        }
    }

    if ( fft_tables->cfg[logm][0] )
    {
        unsigned int i;
        
        for ( i = 0; i < nfft; i++ )
        {
            fin[i] = x[i];    
        }
        
        kiss_fftr( (kiss_fftr_cfg)fft_tables->cfg[logm][0], fin, fout );

        for ( i = 0; i < nfft / 2; i++ )
        {
            x[i]            = fout[i].r;
            x[i + nfft / 2] = fout[i].i;
        }
    }
    else
    {
        fprintf( stderr, "bad config for logm = %d\n", logm);
        exit( 1 );
    }
#endif
}

void fft( FFT_Tables *fft_tables, double *xr, double *xi, int logm )
{
    int nfft = 0;

    kiss_fft_cpx    fin[1 << MAXLOGM];
    kiss_fft_cpx    fout[1 << MAXLOGM];

    if ( logm > MAXLOGM )
	{
		fprintf(stderr, "fft size too big\n");
		exit(1);
	}

    nfft = logm_to_nfft[logm];

    if ( fft_tables->cfg[logm][0] == NULL )
    {
        if ( nfft )
        {
            fft_tables->cfg[logm][0] = kiss_fft_alloc( nfft, 0, NULL, NULL );
        }
        else
        {
	    	fprintf(stderr, "bad logm = %d\n", logm);
            exit( 1 );
        }
    }

    if ( fft_tables->cfg[logm][0] )
    {
        unsigned int i;
        
        for ( i = 0; i < nfft; i++ )
        {
            fin[i].r = xr[i];    
            fin[i].i = xi[i];
        }
        
        kiss_fft( (kiss_fft_cfg)fft_tables->cfg[logm][0], fin, fout );

        for ( i = 0; i < nfft; i++ )
        {
            xr[i]   = fout[i].r;
            xi[i]   = fout[i].i;
        }
    }
    else
    {
        fprintf( stderr, "bad config for logm = %d\n", logm);
        exit( 1 );
    }
}

void ffti( FFT_Tables *fft_tables, double *xr, double *xi, int logm )
{
    int nfft = 0;

    kiss_fft_cpx    fin[1 << MAXLOGM];
    kiss_fft_cpx    fout[1 << MAXLOGM];

    if ( logm > MAXLOGM )
	{
		fprintf(stderr, "fft size too big\n");
		exit(1);
	}

    nfft = logm_to_nfft[logm];

    if ( fft_tables->cfg[logm][1] == NULL )
    {
        if ( nfft )
        {
            fft_tables->cfg[logm][1] = kiss_fft_alloc( nfft, 1, NULL, NULL );
        }
        else
        {
	    	fprintf(stderr, "bad logm = %d\n", logm);
            exit( 1 );
        }
    }
    
    if ( fft_tables->cfg[logm][1] )
    {
        unsigned int i;
        double fac = 1.0 / (double)nfft;
        
        for ( i = 0; i < nfft; i++ )
        {
            fin[i].r = xr[i];    
            fin[i].i = xi[i];
        }
        
        kiss_fft( (kiss_fft_cfg)fft_tables->cfg[logm][1], fin, fout );

        for ( i = 0; i < nfft; i++ )
        {
            xr[i]   = fout[i].r * fac;
            xi[i]   = fout[i].i * fac;
        }
    }
    else
    {
        fprintf( stderr, "bad config for logm = %d\n", logm);
        exit( 1 );
    }
}

/* sur: Trying to use cfft from libfaad2 -- it does not work 'from scratch' */
//
//#include "cfft/common.h"
//
//void fft_initialize( FFT_Tables *fft_tables )
//{
//    memset( fft_tables->cfft, 0, sizeof( fft_tables->cfft ) );
//}
//void fft_terminate( FFT_Tables *fft_tables )
//{
//    unsigned int i;
//    for ( i = 0; i < sizeof( fft_tables->cfft ) / sizeof( fft_tables->cfft[0] ); i++ )
//    {
//        if ( fft_tables->cfft[i] )
//        {
//            cfftu( fft_tables->cfft[i] );
//            fft_tables->cfft[i] = NULL;
//        }
//    }
//}
//
//void rfft( FFT_Tables *fft_tables, double *x, int logm )
//{
//	double xi[1 << MAXLOGR];
//
//    int nfft;
//
//    if ( logm > MAXLOGR )
//	{
//		fprintf(stderr, "rfft size too big\n");
//		exit(1);
//	}
//
//    nfft = logm_to_nfft[logm];
//
//    if ( nfft )
//    {
//        unsigned int i;
//
//        for ( i = 0; i < nfft; i++ )
//        {
//            xi[i] = 0.0;
//        }
//	    //memset( xi, 0, nfft * sizeof( xi[0] ) );
//
//	    fft( fft_tables, x, xi, logm );
//
//	    memcpy( x + nfft / 2, xi, ( nfft / 2 ) * sizeof(x[0]) );
//
//#ifdef SUR_DEBUG_FFT
//        {
//            FILE* f = fopen( "fft.log", "at" );
//            
//            fprintf( f, "RFFT(%d)\n", nfft );
//            
//            for ( i = 0; i < nfft; i++ )
//            {
//                fprintf( f, ";%d;%g;%g\n", i, x[i], xi[i] );
//            }
//
//            fclose( f );
//        }
//#endif
//    }
//    else
//    {
//        fprintf( stderr, "bad config for logm = %d\n", logm);
//        exit( 1 );
//    }
//}
//
//void fft( FFT_Tables *fft_tables, double *xr, double *xi, int logm )
//{
//    int nfft;
//
//    complex_t c[1 << MAXLOGM];
//
//    if ( logm > MAXLOGM )
//	{
//		fprintf(stderr, "fft size too big\n");
//		exit(1);
//	}
//
//    nfft = logm_to_nfft[logm];
//
//    if ( fft_tables->cfft[logm] == NULL )
//    {
//        if ( nfft )
//        {