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/*
* Copyright (c) 2003-2004, Mark Borgerding. All rights reserved.
* This file is part of KISS FFT - https://github.com/mborgerding/kissfft
*
* SPDX-License-Identifier: BSD-3-Clause
* See COPYING file for more information.
*/
#include <stdlib.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <png.h>
#include "kiss_fft.h"
#include "kiss_fftr.h"
int nfft=1024;
FILE * fin=NULL;
FILE * fout=NULL;
int navg=20;
int remove_dc=0;
int nrows=0;
float * vals=NULL;
int stereo=0;
static
void config(int argc,char** argv)
{
while (1) {
int c = getopt (argc, argv, "n:r:as");
if (c == -1)
break;
switch (c) {
case 'n': nfft=(int)atoi(optarg);break;
case 'r': navg=(int)atoi(optarg);break;
case 'a': remove_dc=1;break;
case 's': stereo=1;break;
case '?':
fprintf (stderr, "usage options:\n"
"\t-n d: fft dimension(s) [1024]\n"
"\t-r d: number of rows to average [20]\n"
"\t-a : remove average from each fft buffer\n"
"\t-s : input is stereo, channels will be combined before fft\n"
"16 bit machine format real input is assumed\n"
);
default:
fprintf (stderr, "bad %c\n", c);
exit (1);
break;
}
}
if ( optind < argc ) {
if (strcmp("-",argv[optind]) !=0)
fin = fopen(argv[optind],"rb");
++optind;
}
if ( optind < argc ) {
if ( strcmp("-",argv[optind]) !=0 )
fout = fopen(argv[optind],"wb");
++optind;
}
if (fin==NULL)
fin=stdin;
if (fout==NULL)
fout=stdout;
}
#define CHECKNULL(p) if ( (p)==NULL ) do { fprintf(stderr,"CHECKNULL failed @ %s(%d): %s\n",__FILE__,__LINE__,#p );exit(1);} while(0)
typedef struct
{
png_byte r;
png_byte g;
png_byte b;
} rgb_t;
static
void val2rgb(float x,rgb_t *p)
{
const double pi = 3.14159265358979;
p->g = (int)(255*sin(x*pi));
p->r = (int)(255*abs(sin(x*pi*3/2)));
p->b = (int)(255*abs(sin(x*pi*5/2)));
//fprintf(stderr,"%.2f : %d,%d,%d\n",x,(int)p->r,(int)p->g,(int)p->b);
}
static
void cpx2pixels(rgb_t * res,const float * fbuf,size_t n)
{
size_t i;
float minval,maxval,valrange;
minval=maxval=fbuf[0];
for (i = 0; i < n; ++i) {
if (fbuf[i] > maxval) maxval = fbuf[i];
if (fbuf[i] < minval) minval = fbuf[i];
}
fprintf(stderr,"min ==%f,max=%f\n",minval,maxval);
valrange = maxval-minval;
if (valrange == 0) {
fprintf(stderr,"min == max == %f\n",minval);
exit (1);
}
for (i = 0; i < n; ++i)
val2rgb( (fbuf[i] - minval)/valrange , res+i );
}
static
void transform_signal(void)
{
short *inbuf;
kiss_fftr_cfg cfg=NULL;
kiss_fft_scalar *tbuf;
kiss_fft_cpx *fbuf;
float *mag2buf;
int i;
int n;
int avgctr=0;
int nfreqs=nfft/2+1;
CHECKNULL( cfg=kiss_fftr_alloc(nfft,0,0,0) );
CHECKNULL( inbuf=(short*)malloc(sizeof(short)*2*nfft ) );
CHECKNULL( tbuf=(kiss_fft_scalar*)malloc(sizeof(kiss_fft_scalar)*nfft ) );
CHECKNULL( fbuf=(kiss_fft_cpx*)malloc(sizeof(kiss_fft_cpx)*nfreqs ) );
CHECKNULL( mag2buf=(float*)malloc(sizeof(float)*nfreqs ) );
memset(mag2buf,0,sizeof(mag2buf)*nfreqs);
while (1) {
if (stereo) {
n = fread(inbuf,sizeof(short)*2,nfft,fin);
if (n != nfft )
break;
for (i=0;i<nfft;++i)
tbuf[i] = inbuf[2*i] + inbuf[2*i+1];
}else{
n = fread(inbuf,sizeof(short),nfft,fin);
if (n != nfft )
break;
for (i=0;i<nfft;++i)
tbuf[i] = inbuf[i];
}
if (remove_dc) {
float avg = 0;
for (i=0;i<nfft;++i) avg += tbuf[i];
avg /= nfft;
for (i=0;i<nfft;++i) tbuf[i] -= (kiss_fft_scalar)avg;
}
/* do FFT */
kiss_fftr(cfg,tbuf,fbuf);
for (i=0;i<nfreqs;++i)
mag2buf[i] += fbuf[i].r * fbuf[i].r + fbuf[i].i * fbuf[i].i;
if (++avgctr == navg) {
avgctr=0;
++nrows;
vals = (float*)realloc(vals,sizeof(float)*nrows*nfreqs);
float eps = 1;
for (i=0;i<nfreqs;++i)
vals[(nrows - 1) * nfreqs + i] = 10 * log10 ( mag2buf[i] / navg + eps );
memset(mag2buf,0,sizeof(mag2buf[0])*nfreqs);
}
}
free(cfg);
free(inbuf);
free(tbuf);
free(fbuf);
free(mag2buf);
}
static
void make_png(void)
{
png_bytepp row_pointers=NULL;
rgb_t * row_data=NULL;
int i;
int nfreqs = nfft/2+1;
png_structp png_ptr=NULL;
png_infop info_ptr=NULL;
CHECKNULL( png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING,0,0,0) );
CHECKNULL( info_ptr = png_create_info_struct(png_ptr) );
png_init_io(png_ptr, fout );
png_set_IHDR(png_ptr, info_ptr ,nfreqs,nrows,8,PNG_COLOR_TYPE_RGB,PNG_INTERLACE_NONE,PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT );
row_data = (rgb_t*)malloc(sizeof(rgb_t) * nrows * nfreqs) ;
cpx2pixels(row_data, vals, nfreqs*nrows );
row_pointers = realloc(row_pointers, nrows*sizeof(png_bytep));
for (i=0;i<nrows;++i) {
row_pointers[i] = (png_bytep)(row_data + i*nfreqs);
}
png_set_rows(png_ptr, info_ptr, row_pointers);
fprintf(stderr,"creating %dx%d png\n",nfreqs,nrows);
fprintf(stderr,"bitdepth %d \n",png_get_bit_depth(png_ptr,info_ptr ) );
png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY , NULL);
}
int main(int argc,char ** argv)
{
config(argc,argv);
transform_signal();
make_png();
if (fout!=stdout) fclose(fout);
if (fin!=stdin) fclose(fin);
return 0;
}
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