diff options
Diffstat (limited to 'usr.sbin/i4b/dtmfdecode/dtmfdecode.c')
| -rw-r--r-- | usr.sbin/i4b/dtmfdecode/dtmfdecode.c | 152 |
1 files changed, 0 insertions, 152 deletions
diff --git a/usr.sbin/i4b/dtmfdecode/dtmfdecode.c b/usr.sbin/i4b/dtmfdecode/dtmfdecode.c deleted file mode 100644 index 16c68e62e022..000000000000 --- a/usr.sbin/i4b/dtmfdecode/dtmfdecode.c +++ /dev/null @@ -1,152 +0,0 @@ -/* - * ---------------------------------------------------------------------------- - * "THE BEER-WARE LICENSE" (Revision 42): - * <phk@FreeBSD.org> wrote this file. As long as you retain this notice you - * can do whatever you want with this stuff. If we meet some day, and you think - * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp - * ---------------------------------------------------------------------------- - * - * $Id: dtmfdecode.c,v 1.6 1999/12/13 21:25:24 hm Exp $ - * - * $FreeBSD$ - * - * Extract DTMF signalling from ISDN4BSD A-law coded audio data - * - * A-Law to linear conversion from the sox package. - * - */ - -#include <stdio.h> -#include <math.h> - -/* Integer math scaling factor */ -#define FSC (1<<12) - -/* Alaw parameters */ -#define SIGN_BIT (0x80) /* Sign bit for an A-law byte. */ -#define QUANT_MASK (0xf) /* Quantization field mask. */ -#define SEG_SHIFT (4) /* Left shift for segment number. */ -#define SEG_MASK (0x70) /* Segment field mask. */ - -static int -alaw2linear(a_val) - unsigned char a_val; -{ - int t; - int seg; - - a_val ^= 0x55; - - t = (a_val & QUANT_MASK) << 4; - seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT; - switch (seg) { - case 0: - t += 8; - break; - case 1: - t += 0x108; - break; - default: - t += 0x108; - t <<= seg - 1; - } - return ((a_val & SIGN_BIT) ? t : -t); -} - -#ifdef USE_COS -/* The frequencies we're trying to detect */ -static int dtmf[8] = {697, 770, 852, 941, 1209, 1336, 1477, 1633}; -#else -/* precalculated: p1[kk] = (-cos(2 * 3.141592 * dtmf[kk] / 8000.0) * FSC) */ -static int p1[8] = {-3497, -3369, -3212, -3027, -2384, -2040, -1635, -1164}; -#endif - -/* This is the Q of the filter (pole radius) */ -#define POLRAD .99 - -#define P2 ((int)(POLRAD*POLRAD*FSC)) - -int -main(int argc, char **argv) -{ - int i, kk, t, nn, s, so, ia; - int x, c, d, f, h[8], k[8], n, y[8]; -#ifdef USE_COS - int p1[8]; -#endif - int alaw[256]; - char key[256]; - - for (kk = 0; kk < 8; kk++) { - y[kk] = h[kk] = k[kk] = 0; -#ifdef USE_COS - p1[kk] = (-cos(2 * 3.141592 * dtmf[kk] / 8000.0) * FSC); -#endif - } - - for (i = 0; i < 256; i++) { - key[i] = '?'; - alaw[i] = alaw2linear(i) / (32768/FSC); - } - - /* We encode the tones in 8 bits, translate those to symbol */ - key[0x00] = '\0'; - - key[0x11] = '1'; key[0x12] = '4'; key[0x14] = '7'; key[0x18] = '*'; - key[0x21] = '2'; key[0x22] = '5'; key[0x24] = '8'; key[0x28] = '0'; - key[0x41] = '3'; key[0x42] = '6'; key[0x44] = '9'; key[0x48] = '#'; - key[0x81] = 'A'; key[0x82] = 'B'; key[0x84] = 'C'; key[0x88] = 'D'; - - nn = 0; - ia = 0; - so = 0; - t = 0; - while ((i = getchar()) != EOF) - { - t++; - - /* Convert to our format */ - x = alaw[i]; - - /* Input amplitude */ - if (x > 0) - ia += (x - ia) / 128; - else - ia += (-x - ia) / 128; - - /* For each tone */ - s = 0; - for(kk = 0; kk < 8; kk++) { - - /* Turn the crank */ - c = (P2 * (x - k[kk])) / FSC; - d = x + c; - f = (p1[kk] * (d - h[kk])) / FSC; - n = x - k[kk] - c; - k[kk] = h[kk] + f; - h[kk] = f + d; - - /* Detect and Average */ - if (n > 0) - y[kk] += (n - y[kk]) / 64; - else - y[kk] += (-n - y[kk]) / 64; - - /* Threshold */ - if (y[kk] > FSC/10 && y[kk] > ia) - s |= 1 << kk; - } - - /* Hysteresis and noise supressor */ - if (s != so) { -/* printf("x %d %x -> %x\n",t,so, s); */ - nn = 0; - so = s; - } else if (nn++ == 520 && key[s]) { - putchar(key[s]); -/* printf(" %d %x\n",t,s); */ - } - } - putchar('\n'); - return (0); -} |