Improved goertzel documentation
[mirrors/Programs.git] / c / goertzel / goertzel.c
index f5250a0d11e2740e2a4e9987c0bae928c78796a1..96458a5b83c7cc2cacf5bd4536276df77c17221c 100644 (file)
@@ -2,25 +2,8 @@
 #include <math.h>
 #include <getopt.h>
 
-
-/*
-       Usage examples
-       arecord | ./goertzel
-       sox input.mp3 -b 8 -c 1 -r 8000 -t wav - | ./goertzel
-
-       Arguments for DTMF decoding:
-       -f 697 -f 770 -f 852 -f 941 -f 1209 -f 1336 -f 1477 -f 1633 -t 10
-*/
-
 float goertzel_mag(int numSamples,int 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;
@@ -54,7 +37,61 @@ float goertzel_mag(int numSamples,int TARGET_FREQUENCY,int SAMPLING_RATE, float*
 }
 
 void print_help(char ** argv) {
-       printf("help me %s\n", argv[0]);
+       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 <ratio>\tFrame size (default 2) (samplerate will be divided by this number to get frame size same as -c)\n"
+               "\n"
+               "\t-f <freq>\tAdd frequency in Hz to detect (use multiple times, if no added 440 Hz will be...)\n"
+               "\n"
+               "\t-t <treshold>\tSet treshold (used to hide magnitudes lower than treshold) (defaults -1)\n"
+               "\t-n\t\tPrint integers rather than floats\n"
+               "\t-l\t\tDo not repeat values while still over treshold\n"
+               "\t-b\t\tDo not print first value that will fall under treshold\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(int *freqs, int freq) {
@@ -65,40 +102,49 @@ void addfreq(int *freqs, int freq) {
 }
 
 int main(int argc, char ** argv) {
-       /*
-       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);
-       */
-
        int samplerate = 8000;
        int samplecount = 4000;
        int treshold = -1;
        char noreturn = 0;
+       char repeat = 1;
        char integers=0;
        char verbose=1;
        int freqs[argc+1]; freqs[0]=-1;
 
        int opt;
-       while ((opt = getopt(argc, argv, "?r:s:f:t:iqn")) != -1) {
+       while ((opt = getopt(argc, argv, "?i:o:a:r:c:d:f:t:nlbq")) != -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 's':
+                       case 'c':
                                samplecount = atoi(optarg);
                                break;
+                       case 'd':
+                               samplecount = samplerate/atoi(optarg);
+                               break;
                        case 'f':
                                addfreq(freqs, atoi(optarg));
                                break;
                        case 't':
                                treshold = atoi(optarg);
                                break;
-                       case 'i':
+                       case 'n':
                                integers = 1;
                                break;
-                       case 'n':
+                       case 'l':
+                               repeat = 0;
+                               break;
+                       case 'b':
                                noreturn = 1;
                                break;
                        case 'q':
@@ -152,7 +198,7 @@ int main(int argc, char ** argv) {
 
                        //Set print true if over treshold or if changed to false (print for the last time after going under treshold)
                        printnow = power[i] > treshold;
-                       print = print || printnow || (printlast && !noreturn);
+                       print = !(!repeat && printlast && !(!printnow)) && (print || printnow || (printlast && !noreturn));
                }
                printlast = printnow;
                fflush(stdout);
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