1 /*
2 * Copyright (c) 2003-2004, Mark Borgerding. All rights reserved.
3 * This file is part of KISS FFT - https://github.com/mborgerding/kissfft
4 *
5 * SPDX-License-Identifier: BSD-3-Clause
6 * See COPYING file for more information.
7 */
8
9 #include <stdlib.h>
10 #include <math.h>
11 #include <stdio.h>
12 #include <string.h>
13 #include <unistd.h>
14 #include <png.h>
15
16 #include "kiss_fft.h"
17 #include "kiss_fftr.h"
18
19 int nfft=1024;
20 FILE * fin=NULL;
21 FILE * fout=NULL;
22
23 int navg=20;
24 int remove_dc=0;
25 int nrows=0;
26 float * vals=NULL;
27 int stereo=0;
28
29 static
config(int argc,char ** argv)30 void config(int argc,char** argv)
31 {
32 while (1) {
33 int c = getopt (argc, argv, "n:r:as");
34 if (c == -1)
35 break;
36 switch (c) {
37 case 'n': nfft=(int)atoi(optarg);break;
38 case 'r': navg=(int)atoi(optarg);break;
39 case 'a': remove_dc=1;break;
40 case 's': stereo=1;break;
41 case '?':
42 fprintf (stderr, "usage options:\n"
43 "\t-n d: fft dimension(s) [1024]\n"
44 "\t-r d: number of rows to average [20]\n"
45 "\t-a : remove average from each fft buffer\n"
46 "\t-s : input is stereo, channels will be combined before fft\n"
47 "16 bit machine format real input is assumed\n"
48 );
49 default:
50 fprintf (stderr, "bad %c\n", c);
51 exit (1);
52 break;
53 }
54 }
55 if ( optind < argc ) {
56 if (strcmp("-",argv[optind]) !=0)
57 fin = fopen(argv[optind],"rb");
58 ++optind;
59 }
60
61 if ( optind < argc ) {
62 if ( strcmp("-",argv[optind]) !=0 )
63 fout = fopen(argv[optind],"wb");
64 ++optind;
65 }
66 if (fin==NULL)
67 fin=stdin;
68 if (fout==NULL)
69 fout=stdout;
70 }
71
72 #define CHECKNULL(p) if ( (p)==NULL ) do { fprintf(stderr,"CHECKNULL failed @ %s(%d): %s\n",__FILE__,__LINE__,#p );exit(1);} while(0)
73
74 typedef struct
75 {
76 png_byte r;
77 png_byte g;
78 png_byte b;
79 } rgb_t;
80
81 static
val2rgb(float x,rgb_t * p)82 void val2rgb(float x,rgb_t *p)
83 {
84 const double pi = 3.14159265358979;
85 p->g = (int)(255*sin(x*pi));
86 p->r = (int)(255*abs(sin(x*pi*3/2)));
87 p->b = (int)(255*abs(sin(x*pi*5/2)));
88 //fprintf(stderr,"%.2f : %d,%d,%d\n",x,(int)p->r,(int)p->g,(int)p->b);
89 }
90
91 static
cpx2pixels(rgb_t * res,const float * fbuf,size_t n)92 void cpx2pixels(rgb_t * res,const float * fbuf,size_t n)
93 {
94 size_t i;
95 float minval,maxval,valrange;
96 minval=maxval=fbuf[0];
97
98 for (i = 0; i < n; ++i) {
99 if (fbuf[i] > maxval) maxval = fbuf[i];
100 if (fbuf[i] < minval) minval = fbuf[i];
101 }
102
103 fprintf(stderr,"min ==%f,max=%f\n",minval,maxval);
104 valrange = maxval-minval;
105 if (valrange == 0) {
106 fprintf(stderr,"min == max == %f\n",minval);
107 exit (1);
108 }
109
110 for (i = 0; i < n; ++i)
111 val2rgb( (fbuf[i] - minval)/valrange , res+i );
112 }
113
114 static
transform_signal(void)115 void transform_signal(void)
116 {
117 short *inbuf;
118 kiss_fftr_cfg cfg=NULL;
119 kiss_fft_scalar *tbuf;
120 kiss_fft_cpx *fbuf;
121 float *mag2buf;
122 int i;
123 int n;
124 int avgctr=0;
125
126 int nfreqs=nfft/2+1;
127
128 CHECKNULL( cfg=kiss_fftr_alloc(nfft,0,0,0) );
129 CHECKNULL( inbuf=(short*)malloc(sizeof(short)*2*nfft ) );
130 CHECKNULL( tbuf=(kiss_fft_scalar*)malloc(sizeof(kiss_fft_scalar)*nfft ) );
131 CHECKNULL( fbuf=(kiss_fft_cpx*)malloc(sizeof(kiss_fft_cpx)*nfreqs ) );
132 CHECKNULL( mag2buf=(float*)malloc(sizeof(float)*nfreqs ) );
133
134 memset(mag2buf,0,sizeof(mag2buf)*nfreqs);
135
136 while (1) {
137 if (stereo) {
138 n = fread(inbuf,sizeof(short)*2,nfft,fin);
139 if (n != nfft )
140 break;
141 for (i=0;i<nfft;++i)
142 tbuf[i] = inbuf[2*i] + inbuf[2*i+1];
143 }else{
144 n = fread(inbuf,sizeof(short),nfft,fin);
145 if (n != nfft )
146 break;
147 for (i=0;i<nfft;++i)
148 tbuf[i] = inbuf[i];
149 }
150
151 if (remove_dc) {
152 float avg = 0;
153 for (i=0;i<nfft;++i) avg += tbuf[i];
154 avg /= nfft;
155 for (i=0;i<nfft;++i) tbuf[i] -= (kiss_fft_scalar)avg;
156 }
157
158 /* do FFT */
159 kiss_fftr(cfg,tbuf,fbuf);
160
161 for (i=0;i<nfreqs;++i)
162 mag2buf[i] += fbuf[i].r * fbuf[i].r + fbuf[i].i * fbuf[i].i;
163
164 if (++avgctr == navg) {
165 avgctr=0;
166 ++nrows;
167 vals = (float*)realloc(vals,sizeof(float)*nrows*nfreqs);
168 float eps = 1;
169 for (i=0;i<nfreqs;++i)
170 vals[(nrows - 1) * nfreqs + i] = 10 * log10 ( mag2buf[i] / navg + eps );
171 memset(mag2buf,0,sizeof(mag2buf[0])*nfreqs);
172 }
173 }
174
175 free(cfg);
176 free(inbuf);
177 free(tbuf);
178 free(fbuf);
179 free(mag2buf);
180 }
181
182 static
make_png(void)183 void make_png(void)
184 {
185 png_bytepp row_pointers=NULL;
186 rgb_t * row_data=NULL;
187 int i;
188 int nfreqs = nfft/2+1;
189
190 png_structp png_ptr=NULL;
191 png_infop info_ptr=NULL;
192
193 CHECKNULL( png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING,0,0,0) );
194 CHECKNULL( info_ptr = png_create_info_struct(png_ptr) );
195
196
197 png_init_io(png_ptr, fout );
198 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 );
199
200
201 row_data = (rgb_t*)malloc(sizeof(rgb_t) * nrows * nfreqs) ;
202 cpx2pixels(row_data, vals, nfreqs*nrows );
203
204 row_pointers = realloc(row_pointers, nrows*sizeof(png_bytep));
205 for (i=0;i<nrows;++i) {
206 row_pointers[i] = (png_bytep)(row_data + i*nfreqs);
207 }
208 png_set_rows(png_ptr, info_ptr, row_pointers);
209
210
211 fprintf(stderr,"creating %dx%d png\n",nfreqs,nrows);
212 fprintf(stderr,"bitdepth %d \n",png_get_bit_depth(png_ptr,info_ptr ) );
213
214 png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY , NULL);
215
216 }
217
main(int argc,char ** argv)218 int main(int argc,char ** argv)
219 {
220 config(argc,argv);
221
222 transform_signal();
223
224 make_png();
225
226 if (fout!=stdout) fclose(fout);
227 if (fin!=stdin) fclose(fin);
228 return 0;
229 }
230