#include <stdio.h>
#include <math.h>
+#include <getopt.h>
-/*
- Usage examples
- arecord | ./goertzel
- sox input.mp3 -b 8 -c 1 -r 8000 -t wav - | ./goertzel
-*/
-
-float goertzel_mag(int numSamples,int TARGET_FREQUENCY,int SAMPLING_RATE, float* data)
+float goertzel_mag(int numSamples,float TARGET_FREQUENCY,int SAMPLING_RATE, float* data)
{
- /*
- On lower samplerates and frame sizes this may perform sub-optimally. Eg.:
- When set to detect 440Hz (at 8000Hz samplerate and ~4000 samples)
- it actually detects something around 438,3Hz rather than 400Hz...
- If you can't increase samplerate way around this is just to increase sensitivity.
- */
-
int k,i;
float floatnumSamples;
float omega,sine,cosine,coeff,q0,q1,q2,magnitude,real,imag;
float scalingFactor = numSamples / 2.0;
floatnumSamples = (float) numSamples;
- k = (int) (0.5 + ((floatnumSamples * TARGET_FREQUENCY) / SAMPLING_RATE));
+ k = (int) (0.5 + ((floatnumSamples * TARGET_FREQUENCY) / (float)SAMPLING_RATE));
omega = (2.0 * M_PI * k) / floatnumSamples;
sine = sin(omega);
cosine = cos(omega);
// calculate the real and imaginary results
// scaling appropriately
- real = (q1 - q2 * cosine) / scalingFactor;
- imag = (q2 * sine) / scalingFactor;
+ real = (q2 - q1 * cosine) / scalingFactor;
+ imag = (q1 * sine) / scalingFactor;
magnitude = sqrtf(real*real + imag*imag);
return magnitude;
}
-int main() {
- /*
- int samples[] = {0,1,2,3,4,5,6,7,8,9,8,7,6,5,4,3,2,1};
- int samplecount = 18;
- float power = goertzel(samplecount, samples, 1.2, 18);
- printf("G: %f\n", power);
- */
+void print_help(char ** argv) {
+ printf(
+ "%s takes raw (wav) audio stream and computes power (or magnitude)\n"
+ "of desired frequencies using Goertzel algorithm for time frames\n"
+ "of fixed length (specified in samples or relative to sample rate).\n"
+ "This can be used in various frequency detection applications\n"
+ "like guitar tuning, DTMF decoding and many others...\n"
+ "\n"
+ "http://en.wikipedia.org/wiki/Goertzel_algorithm\n"
+ "\n"
+ "Curently only raw unsigned 8bit (u8) mono audio is supported, but\n"
+ "samplerate may vary. You can convert other formats before processing.\n"
+ "\n"
+ "On lower samplerates and frame sizes this may perform sub-optimally. Eg.:\n"
+ "When set to detect 440Hz (at 8000Hz samplerate and ~4000 samples)\n"
+ "it actually detects something around 438,3Hz rather than 400Hz...\n"
+ "If you can't increase samplerate way around this is just to increase sensitivity.\n"
+ "\n"
+ ,argv[0]
+ );
+
+ printf(
+ "Arguments:\n"
+ "\t-i <file>\tInput from file (default STDIN)\n"
+ "\t-o <file>\tOutput to file (default STDOUT)\n"
+ "\t-a <file>\tOutput to file (append) (default STDOUT)\n"
+ "\n"
+ "\t-r <samplerate>\tInput samplerate (deault 8000 Hz)\n"
+ "\t-c <count>\tFrame size in samples (default 4000 Samples)\n"
+ "\t-d <divisor>\tFrame size ( count = samplerate/divisor ) (default 2)\n"
+ "\n"
+ "\t-f <freq>\tAdd frequency in Hz to detect (use multiple times, default 440 Hz)\n"
+ "\n"
+ "\t-n <format>\tSet number output format\n"
+ "\t\tf: float\t23.4223 (default)\n"
+ "\t\ti: integer\t23\n"
+ "\t\tb: binary\t(0|1)\n"
+ "\t\tB: Boolean\t(false|true)\n"
+ "\n"
+ "\t-t <treshold>\tSet treshold (used in filter, see -l) (defaults -1)\n"
+ "\t-l <filter>\tSet line filter\n"
+ "\t\tf: Falldown:\tprint only when over treshold or just crossed (default)\n"
+ "\t\tt: Treshold:\tprint only when over treshold\n"
+ "\t\tc: Crossed:\tprint only when treshold crossed\n"
+ "\t-u\t\tInvert\ttreshold (values under treshold will be displayed)\n"
+ "\n"
+ "\t-q\t\tQuiet mode: print only values\n"
+ "\n"
+ "\t-?\t\tPrint help\n"
+ "\n"
+ );
+
+ printf(
+ "Usage examples:\n"
+ "\tarecord | %s\n"
+ "\tsox input.mp3 -b 8 -c 1 -r 8000 -t wav - | %s\n"
+ "\t%s -n -q -l -r 8000 -d 20 -t $tresh -f 697 [-f 770 ...]\n"
+ "\n"
+ ,argv[0],argv[0],argv[0]
+ );
+
+ printf(
+ "Frequencies for DTMF decoding:\n"
+ "\t-f 697 -f 770 -f 852 -f 941 -f 1209 -f 1336 -f 1477 -f 1633 -t 10\n"
+ );
+}
+
+void addfreq(float *freqs, float freq) {
+ int i = 0;
+ while(freqs[i]!=-1) i++;
+ freqs[i]=freq;
+ freqs[i+1]=-1;
+}
+int main(int argc, char ** argv) {
int samplerate = 8000;
int samplecount = 4000;
+
+ int treshold = -1;
+ char filter = 0;
+ char under = 0;
+
+ char format=0;
+ char verbose=1;
+
+ float freqs[argc+1]; freqs[0]=-1;
+
+
+ float floatarg;
+ int opt;
+ while ((opt = getopt(argc, argv, "?i:o:a:r:c:d:f:t:n:l:uq")) != -1) {
+ switch (opt) {
+ case 'i':
+ freopen(optarg, "r", stdin);
+ break;
+ case 'o':
+ freopen(optarg, "w", stdout);
+ break;
+ case 'a':
+ freopen(optarg, "a", stdout);
+ break;
+ case 'r':
+ samplerate = atoi(optarg);
+ break;
+ case 'c':
+ samplecount = atoi(optarg);
+ break;
+ case 'd':
+ samplecount = samplerate/atoi(optarg);
+ break;
+ case 'f':
+ sscanf(optarg,"%f",&floatarg);
+ addfreq(freqs, floatarg);
+ break;
+ case 't':
+ treshold = atoi(optarg);
+ break;
+ case 'n':
+ format = optarg[0];
+ break;
+ case 'l':
+ filter = optarg[0];
+ break;
+ case 'u':
+ under = 1;
+ break;
+ case 'q':
+ verbose = 0;
+ break;
+ case '?':
+ print_help(argv);
+ return 0;
+ break;
+ }
+ }
+
+ if(freqs[0]==-1) addfreq(freqs, 440);
float samples[samplecount];
float position = 0;
- fprintf(stderr,"Position (Secs)\tMagnitude\n");
+
+ if(verbose) {
+ fprintf(stderr,
+ "#Detected tone: %.2f Hz\n"
+ "#Samplerate: %d Hz\n"
+ "#Frame lenght: %d samples\n"
+ "#Treshold: %d\n"
+ "#\n"
+ ,freqs[0],samplerate,samplecount,treshold);
+ fflush(stderr);
+
+ printf("#Position");
+ int i; for(i=0;freqs[i]!=-1;i++) {
+ printf("\t%2.0fHz",freqs[i]); //TODO: print decimal places
+ }
+ puts("");
+ }
+
+ int i;
+ char print=0, printnow=0;
+ char laststate[argc]; for(i=0;freqs[i]!=-1;i++) laststate[i]=-1;
while(!feof(stdin)) {
- int i;
+
+ //Sample data
for(i=0;i<samplecount && !feof(stdin);i++) {
unsigned char sample;
fread(&sample,1,1,stdin);
samples[i]=sample;
//printf("%d\n", sample);
}
+
+ //Apply goertzel
+ float power[argc];
+ print=0;
+ for(i=0;freqs[i]!=-1;i++) {
+ power[i] = goertzel_mag(samplecount, freqs[i], samplerate, samples);
+
+ //Decide if we will print
+ printnow = under ? power[i] < treshold : power[i] > treshold; //Is over/under treshold?
+ switch(filter) {
+ case 'c': //Print if treshold crossed
+ print = print || (laststate[i] != printnow);
+ break;
+ default:
+ case 'f': //Print if over treshold or falled down
+ print = print || (laststate[i] != printnow);
+ case 't': //Print if over treshold
+ print = print || printnow;
+ }
+ laststate[i] = printnow; //Store last state
+ }
+ fflush(stdout);
+
+ //Print data
+ if(print) {
+ printf("%8.2f", position);
+ for(i=0;freqs[i]!=-1;i++) {
+ printf("\t");
+ switch(format) {
+ case 'i':
+ printf("%d",(int)round(power[i]));
+ break;
+ case 'b':
+ printf("%d",power[i]>treshold);
+ break;
+ case 'B':
+ if(power[i]>treshold) printf("true");
+ else printf("false");
+ break;
+ case 'f':
+ default:
+ printf("%7.5f",power[i]);
+ }
+ }
+ puts("");
+ fflush(stdout);
+ }
+
+ //Increase time
position += ((float)samplecount/(float)samplerate);
- float power = goertzel_mag(samplecount, 440, samplerate, samples);
- printf("%f\t%f\n", position, power);
}
}
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