Hi! I use followinc c code to check record level. It will take two optinal parameters: positive integer is time in seconds and negative interger is warning level in decibels when program will send bell character to terminal in addition to normal output. Output is rms level and peak leven. -- Mr. Ari Moisio, Niittykatu 7, 41160 Tikkakoski, +358-40-5055239 ari.moisio at iki.fi http://www.iki.fi/arimo PGP-keyID: 0x3FAF0F05 // Record level 'meter' // Results: rms / peak in db. // Compile gcc -lm vumeter.c -o vumeter #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <math.h> int signo = 0; void handler(int sno) { signo = sno; } int main(int argc, char **argv) { int t_val, max, secs = 5, retval = 0, c_rms = 0, warn = -1, tmp; long s_cnt = 0, s_sum = 0; float level = 0.0, rms=0.0, max_level=99.9, s_rms=0.0; FILE *dsp_fd; signal(SIGINT, handler); for (tmp = 1; tmp < argc; tmp++) { t_val = atoi(argv[tmp]); if (t_val > 0) secs = t_val; if (t_val < 0) warn = -t_val; } // endfor dsp_fd = fopen("/dev/dsp","r"); max = 0; s_sum = 0; for (; secs > 0 && signo == 0; secs -= 1) { max = 0; s_sum = 0; s_cnt = 0; for (s_cnt = 1; s_cnt <= 8000; s_cnt++) { t_val = fgetc(dsp_fd) - 0x80; if (t_val < 0) t_val = -t_val; if (t_val > 127) t_val = 127; if (t_val > max) max = t_val; s_sum += t_val * t_val; } // endfor if (signo ==0) { level = (log10(127.0 / max)) * 20; rms = (log10(127.0 / sqrt(s_sum / s_cnt)) * 20); if (level < warn) printf("\a"); printf("%4.1f / %4.1f\n", -rms, -level); if (level < max_level) max_level = level; s_rms += rms; c_rms++; } // endif signo eq 0 } // endfor secs fclose(dsp_fd); printf("============\n%4.1f / %4.1f\n", -s_rms / c_rms, -max_level); retval = floor(max_level); return retval; }
