Sat Aug 6 00:39:57 2011

Asterisk developer's documentation


gentone.c File Reference

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

Go to the source code of this file.

Defines

#define BIAS   0x84
#define CLIP   32635

Functions

static int calc_samples (int freq)
int main (int argc, char *argv[])

Variables

static float loudness = 16384.0


Define Documentation

#define BIAS   0x84

Definition at line 10 of file gentone.c.

#define CLIP   32635

Definition at line 9 of file gentone.c.


Function Documentation

static int calc_samples ( int  freq  )  [static]

Definition at line 13 of file gentone.c.

00014 {
00015    int x, samples;
00016    /* Calculate the number of samples at 8000hz sampling
00017       we need to have this wave form */
00018    samples = 8000;
00019    /* Take out common 2's up to six times */
00020    for (x=0;x<6;x++) 
00021       if (!(freq % 2)) {
00022          freq /= 2;
00023          samples /= 2;
00024       }
00025    /* Take out common 5's (up to three times */
00026    for (x=0;x<3;x++) 
00027       if (!(freq % 5)) {
00028          freq /= 5;
00029          samples /=5;
00030       }
00031    /* No more common factors. */
00032    return samples;
00033 }

int main ( int  argc,
char *  argv[] 
)

Definition at line 35 of file gentone.c.

References calc_samples(), f, and loudness.

00036 {
00037    FILE *f;
00038    int freq1, freq2;
00039    float wlen1, wlen2;
00040    float val;
00041    int x, samples1, samples2=0, samples=0;
00042    char fn[256];
00043    if (argc < 3) {
00044       fprintf(stderr, "Usage: gensound <name> <freq1> [freq2]\n");
00045       exit(1);
00046    }
00047    freq1 = atoi(argv[2]);
00048    if (argc > 3) 
00049       freq2 = atoi(argv[3]);
00050    else
00051       freq2 = 0;
00052    wlen1 = 8000.0/(float)freq1;
00053    samples1 = calc_samples(freq1);
00054    printf("Wavelength 1 (in samples): %10.5f\n", wlen1);
00055    printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples1, samples1 / wlen1);
00056    if (freq2) {
00057       wlen2 = 8000.0/(float)freq2;
00058       samples2 = calc_samples(freq2);
00059       printf("Wavelength 1 (in samples): %10.5f\n", wlen2);
00060       printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples2, samples2 / wlen2);
00061    }
00062    samples = samples1;
00063    if (freq2) {
00064       while(samples % samples2)
00065          samples += samples1;
00066    }
00067    printf("Need %d samples\n", samples);
00068    snprintf(fn, sizeof(fn), "%s.h", argv[1]);
00069    if ((f = fopen(fn, "w"))) {
00070       if (freq2) 
00071          fprintf(f, "/* %s: Generated from frequencies %d and %d \n"
00072                     "   by gentone.  %d samples  */\n", fn, freq1, freq2, samples); 
00073       else
00074          fprintf(f, "/* %s: Generated from frequency %d\n"
00075                     "   by gentone.  %d samples  */\n", fn, freq1, samples); 
00076       fprintf(f, "static short %s[%d] = {\n\t", argv[1], samples);
00077       for (x=0;x<samples;x++) {
00078          val = loudness * sin((freq1 * 2.0 * M_PI * x)/8000.0);
00079          if (freq2)
00080             val += loudness * sin((freq2 * 2.0 * M_PI * x)/8000.0);
00081          fprintf(f, "%5d, ", (int)val);
00082          if (!((x+1) % 8)) 
00083             fprintf(f, "\n\t");
00084       }
00085       if (x % 15)
00086          fprintf(f, "\n");
00087       fprintf(f, "};\n");
00088       fclose(f);
00089       printf("Wrote %s\n", fn);
00090    } else {
00091       fprintf(stderr, "Unable to open %s for writing\n", fn);
00092       return 1;
00093    }
00094    return 0;
00095 }   


Variable Documentation

float loudness = 16384.0 [static]

Definition at line 11 of file gentone.c.


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