#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 | BIAS 0x84 |
#define | CLIP 32635 |
#define | CLIP 32635 |
#define | ZEROTRAP |
Functions | |
static int | calc_samples (int freq) |
static unsigned char | linear2ulaw (short sample) |
int | main (int argc, char *argv[]) |
Variables | |
static float | loudness = 16384.0 |
#define BIAS 0x84 |
Definition at line 57 of file gentone-ulaw.c.
#define BIAS 0x84 |
Definition at line 57 of file gentone-ulaw.c.
#define CLIP 32635 |
Definition at line 58 of file gentone-ulaw.c.
#define CLIP 32635 |
Definition at line 58 of file gentone-ulaw.c.
#define ZEROTRAP |
Definition at line 56 of file gentone-ulaw.c.
static int calc_samples | ( | int | freq | ) | [static] |
Definition at line 13 of file gentone-ulaw.c.
Referenced by main().
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 }
static unsigned char linear2ulaw | ( | short | sample | ) | [static] |
Definition at line 60 of file gentone-ulaw.c.
00060 { 00061 static int exp_lut[256] = {0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3, 00062 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, 00063 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 00064 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 00065 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 00066 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 00067 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 00068 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 00069 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 00070 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 00071 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 00072 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 00073 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 00074 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 00075 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 00076 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7}; 00077 int sign, exponent, mantissa; 00078 unsigned char ulawbyte; 00079 00080 /* Get the sample into sign-magnitude. */ 00081 sign = (sample >> 8) & 0x80; /* set aside the sign */ 00082 if (sign != 0) sample = -sample; /* get magnitude */ 00083 if (sample > CLIP) sample = CLIP; /* clip the magnitude */ 00084 00085 /* Convert from 16 bit linear to ulaw. */ 00086 sample = sample + BIAS; 00087 exponent = exp_lut[(sample >> 7) & 0xFF]; 00088 mantissa = (sample >> (exponent + 3)) & 0x0F; 00089 ulawbyte = ~(sign | (exponent << 4) | mantissa); 00090 #ifdef ZEROTRAP 00091 if (ulawbyte == 0) ulawbyte = 0x02; /* optional CCITT trap */ 00092 #endif 00093 00094 return(ulawbyte); 00095 }
int main | ( | int | argc, | |
char * | argv[] | |||
) |
Definition at line 97 of file gentone-ulaw.c.
References calc_samples(), f, linear2ulaw(), and loudness.
00098 { 00099 FILE *f; 00100 int freq1, freq2; 00101 float wlen1, wlen2; 00102 float val; 00103 int x, samples1, samples2, samples=0; 00104 char fn[256]; 00105 if (argc < 3) { 00106 fprintf(stderr, "Usage: gensound <name> <freq1> [freq2]\n"); 00107 exit(1); 00108 } 00109 freq1 = atoi(argv[2]); 00110 if (argc > 3) 00111 freq2 = atoi(argv[3]); 00112 else 00113 freq2 = 0; 00114 wlen1 = 8000.0/(float)freq1; 00115 samples1 = calc_samples(freq1); 00116 printf("Wavelength 1 (in samples): %10.5f\n", wlen1); 00117 printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples1, samples1 / wlen1); 00118 if (freq2) { 00119 wlen2 = 8000.0/(float)freq2; 00120 samples2 = calc_samples(freq2); 00121 printf("Wavelength 1 (in samples): %10.5f\n", wlen2); 00122 printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples2, samples2 / wlen2); 00123 } 00124 samples = samples1; 00125 if (freq2) { 00126 while(samples % samples2) 00127 samples += samples1; 00128 } 00129 printf("Need %d samples\n", samples); 00130 snprintf(fn, sizeof(fn), "%s.h", argv[1]); 00131 if ((f = fopen(fn, "w"))) { 00132 if (freq2) 00133 fprintf(f, "/* %s: Generated from frequencies %d and %d \n" 00134 " by gentone. %d samples */\n", fn, freq1, freq2, samples); 00135 else 00136 fprintf(f, "/* %s: Generated from frequency %d\n" 00137 " by gentone. %d samples */\n", fn, freq1, samples); 00138 fprintf(f, "static unsigned char %s[%d] = {\n\t", argv[1], samples); 00139 for (x=0;x<samples;x++) { 00140 val = loudness * sin((freq1 * 2.0 * M_PI * x)/8000.0); 00141 if (freq2) 00142 val += loudness * sin((freq2 * 2.0 * M_PI * x)/8000.0); 00143 fprintf(f, "%3d, ", (int) linear2ulaw(val)); 00144 if (!((x+1) % 8)) 00145 fprintf(f, "\n\t"); 00146 } 00147 if (x % 15) 00148 fprintf(f, "\n"); 00149 fprintf(f, "};\n"); 00150 fclose(f); 00151 printf("Wrote %s\n", fn); 00152 } else { 00153 fprintf(stderr, "Unable to open %s for writing\n", fn); 00154 return 1; 00155 } 00156 return 0; 00157 }
float loudness = 16384.0 [static] |