/* $Id: isdn_audio.c,v 1.1.4.1 2001/11/20 14:19:33 kai Exp $ * * Linux ISDN subsystem, audio conversion and compression (linklevel). * * Copyright 1994-1999 by Fritz Elfert (fritz@isdn4linux.de) * DTMF code (c) 1996 by Christian Mock (cm@kukuruz.ping.at) * Silence detection (c) 1998 by Armin Schindler (mac@gismo.telekom.de) * * This software may be used and distributed according to the terms * of the GNU General Public License, incorporated herein by reference. * */ #include #include "isdn_audio.h" #include "isdn_common.h" char *isdn_audio_revision = "$Revision: 1.1.4.1 $"; /* * Misc. lookup-tables. */ /* ulaw -> signed 16-bit */ static short isdn_audio_ulaw_to_s16[] = { 0x8284, 0x8684, 0x8a84, 0x8e84, 0x9284, 0x9684, 0x9a84, 0x9e84, 0xa284, 0xa684, 0xaa84, 0xae84, 0xb284, 0xb684, 0xba84, 0xbe84, 0xc184, 0xc384, 0xc584, 0xc784, 0xc984, 0xcb84, 0xcd84, 0xcf84, 0xd184, 0xd384, 0xd584, 0xd784, 0xd984, 0xdb84, 0xdd84, 0xdf84, 0xe104, 0xe204, 0xe304, 0xe404, 0xe504, 0xe604, 0xe704, 0xe804, 0xe904, 0xea04, 0xeb04, 0xec04, 0xed04, 0xee04, 0xef04, 0xf004, 0xf0c4, 0xf144, 0xf1c4, 0xf244, 0xf2c4, 0xf344, 0xf3c4, 0xf444, 0xf4c4, 0xf544, 0xf5c4, 0xf644, 0xf6c4, 0xf744, 0xf7c4, 0xf844, 0xf8a4, 0xf8e4, 0xf924, 0xf964, 0xf9a4, 0xf9e4, 0xfa24, 0xfa64, 0xfaa4, 0xfae4, 0xfb24, 0xfb64, 0xfba4, 0xfbe4, 0xfc24, 0xfc64, 0xfc94, 0xfcb4, 0xfcd4, 0xfcf4, 0xfd14, 0xfd34, 0xfd54, 0xfd74, 0xfd94, 0xfdb4, 0xfdd4, 0xfdf4, 0xfe14, 0xfe34, 0xfe54, 0xfe74, 0xfe8c, 0xfe9c, 0xfeac, 0xfebc, 0xfecc, 0xfedc, 0xfeec, 0xfefc, 0xff0c, 0xff1c, 0xff2c, 0xff3c, 0xff4c, 0xff5c, 0xff6c, 0xff7c, 0xff88, 0xff90, 0xff98, 0xffa0, 0xffa8, 0xffb0, 0xffb8, 0xffc0, 0xffc8, 0xffd0, 0xffd8, 0xffe0, 0xffe8, 0xfff0, 0xfff8, 0x0000, 0x7d7c, 0x797c, 0x757c, 0x717c, 0x6d7c, 0x697c, 0x657c, 0x617c, 0x5d7c, 0x597c, 0x557c, 0x517c, 0x4d7c, 0x497c, 0x457c, 0x417c, 0x3e7c, 0x3c7c, 0x3a7c, 0x387c, 0x367c, 0x347c, 0x327c, 0x307c, 0x2e7c, 0x2c7c, 0x2a7c, 0x287c, 0x267c, 0x247c, 0x227c, 0x207c, 0x1efc, 0x1dfc, 0x1cfc, 0x1bfc, 0x1afc, 0x19fc, 0x18fc, 0x17fc, 0x16fc, 0x15fc, 0x14fc, 0x13fc, 0x12fc, 0x11fc, 0x10fc, 0x0ffc, 0x0f3c, 0x0ebc, 0x0e3c, 0x0dbc, 0x0d3c, 0x0cbc, 0x0c3c, 0x0bbc, 0x0b3c, 0x0abc, 0x0a3c, 0x09bc, 0x093c, 0x08bc, 0x083c, 0x07bc, 0x075c, 0x071c, 0x06dc, 0x069c, 0x065c, 0x061c, 0x05dc, 0x059c, 0x055c, 0x051c, 0x04dc, 0x049c, 0x045c, 0x041c, 0x03dc, 0x039c, 0x036c, 0x034c, 0x032c, 0x030c, 0x02ec, 0x02cc, 0x02ac, 0x028c, 0x026c, 0x024c, 0x022c, 0x020c, 0x01ec, 0x01cc, 0x01ac, 0x018c, 0x0174, 0x0164, 0x0154, 0x0144, 0x0134, 0x0124, 0x0114, 0x0104, 0x00f4, 0x00e4, 0x00d4, 0x00c4, 0x00b4, 0x00a4, 0x0094, 0x0084, 0x0078, 0x0070, 0x0068, 0x0060, 0x0058, 0x0050, 0x0048, 0x0040, 0x0038, 0x0030, 0x0028, 0x0020, 0x0018, 0x0010, 0x0008, 0x0000 }; /* alaw -> signed 16-bit */ static short isdn_audio_alaw_to_s16[] = { 0x13fc, 0xec04, 0x0144, 0xfebc, 0x517c, 0xae84, 0x051c, 0xfae4, 0x0a3c, 0xf5c4, 0x0048, 0xffb8, 0x287c, 0xd784, 0x028c, 0xfd74, 0x1bfc, 0xe404, 0x01cc, 0xfe34, 0x717c, 0x8e84, 0x071c, 0xf8e4, 0x0e3c, 0xf1c4, 0x00c4, 0xff3c, 0x387c, 0xc784, 0x039c, 0xfc64, 0x0ffc, 0xf004, 0x0104, 0xfefc, 0x417c, 0xbe84, 0x041c, 0xfbe4, 0x083c, 0xf7c4, 0x0008, 0xfff8, 0x207c, 0xdf84, 0x020c, 0xfdf4, 0x17fc, 0xe804, 0x018c, 0xfe74, 0x617c, 0x9e84, 0x061c, 0xf9e4, 0x0c3c, 0xf3c4, 0x0084, 0xff7c, 0x307c, 0xcf84, 0x030c, 0xfcf4, 0x15fc, 0xea04, 0x0164, 0xfe9c, 0x597c, 0xa684, 0x059c, 0xfa64, 0x0b3c, 0xf4c4, 0x0068, 0xff98, 0x2c7c, 0xd384, 0x02cc, 0xfd34, 0x1dfc, 0xe204, 0x01ec, 0xfe14, 0x797c, 0x8684, 0x07bc, 0xf844, 0x0f3c, 0xf0c4, 0x00e4, 0xff1c, 0x3c7c, 0xc384, 0x03dc, 0xfc24, 0x11fc, 0xee04, 0x0124, 0xfedc, 0x497c, 0xb684, 0x049c, 0xfb64, 0x093c, 0xf6c4, 0x0028, 0xffd8, 0x247c, 0xdb84, 0x024c, 0xfdb4, 0x19fc, 0xe604, 0x01ac, 0xfe54, 0x697c, 0x9684, 0x069c, 0xf964, 0x0d3c, 0xf2c4, 0x00a4, 0xff5c, 0x347c, 0xcb84, 0x034c, 0xfcb4, 0x12fc, 0xed04, 0x0134, 0xfecc, 0x4d7c, 0xb284, 0x04dc, 0xfb24, 0x09bc, 0xf644, 0x0038, 0xffc8, 0x267c, 0xd984, 0x026c, 0xfd94, 0x1afc, 0xe504, 0x01ac, 0xfe54, 0x6d7c, 0x9284, 0x06dc, 0xf924, 0x0dbc, 0xf244, 0x00b4, 0xff4c, 0x367c, 0xc984, 0x036c, 0xfc94, 0x0f3c, 0xf0c4, 0x00f4, 0xff0c, 0x3e7c, 0xc184, 0x03dc, 0xfc24, 0x07bc, 0xf844, 0x0008, 0xfff8, 0x1efc, 0xe104, 0x01ec, 0xfe14, 0x16fc, 0xe904, 0x0174, 0xfe8c, 0x5d7c, 0xa284, 0x05dc, 0xfa24, 0x0bbc, 0xf444, 0x0078, 0xff88, 0x2e7c, 0xd184, 0x02ec, 0xfd14, 0x14fc, 0xeb04, 0x0154, 0xfeac, 0x557c, 0xaa84, 0x055c, 0xfaa4, 0x0abc, 0xf544, 0x0058, 0xffa8, 0x2a7c, 0xd584, 0x02ac, 0xfd54, 0x1cfc, 0xe304, 0x01cc, 0xfe34, 0x757c, 0x8a84, 0x075c, 0xf8a4, 0x0ebc, 0xf144, 0x00d4, 0xff2c, 0x3a7c, 0xc584, 0x039c, 0xfc64, 0x10fc, 0xef04, 0x0114, 0xfeec, 0x457c, 0xba84, 0x045c, 0xfba4, 0x08bc, 0xf744, 0x0018, 0xffe8, 0x227c, 0xdd84, 0x022c, 0xfdd4, 0x18fc, 0xe704, 0x018c, 0xfe74, 0x657c, 0x9a84, 0x065c, 0xf9a4, 0x0cbc, 0xf344, 0x0094, 0xff6c, 0x327c, 0xcd84, 0x032c, 0xfcd4 }; /* alaw -> ulaw */ static char isdn_audio_alaw_to_ulaw[] = { 0xab, 0x2b, 0xe3, 0x63, 0x8b, 0x0b, 0xc9, 0x49, 0xba, 0x3a, 0xf6, 0x76, 0x9b, 0x1b, 0xd7, 0x57, 0xa3, 0x23, 0xdd, 0x5d, 0x83, 0x03, 0xc1, 0x41, 0xb2, 0x32, 0xeb, 0x6b, 0x93, 0x13, 0xcf, 0x4f, 0xaf, 0x2f, 0xe7, 0x67, 0x8f, 0x0f, 0xcd, 0x4d, 0xbe, 0x3e, 0xfe, 0x7e, 0x9f, 0x1f, 0xdb, 0x5b, 0xa7, 0x27, 0xdf, 0x5f, 0x87, 0x07, 0xc5, 0x45, 0xb6, 0x36, 0xef, 0x6f, 0x97, 0x17, 0xd3, 0x53, 0xa9, 0x29, 0xe1, 0x61, 0x89, 0x09, 0xc7, 0x47, 0xb8, 0x38, 0xf2, 0x72, 0x99, 0x19, 0xd5, 0x55, 0xa1, 0x21, 0xdc, 0x5c, 0x81, 0x01, 0xbf, 0x3f, 0xb0, 0x30, 0xe9, 0x69, 0x91, 0x11, 0xce, 0x4e, 0xad, 0x2d, 0xe5, 0x65, 0x8d, 0x0d, 0xcb, 0x4b, 0xbc, 0x3c, 0xfa, 0x7a, 0x9d, 0x1d, 0xd9, 0x59, 0xa5, 0x25, 0xde, 0x5e, 0x85, 0x05, 0xc3, 0x43, 0xb4, 0x34, 0xed, 0x6d, 0x95, 0x15, 0xd1, 0x51, 0xac, 0x2c, 0xe4, 0x64, 0x8c, 0x0c, 0xca, 0x4a, 0xbb, 0x3b, 0xf8, 0x78, 0x9c, 0x1c, 0xd8, 0x58, 0xa4, 0x24, 0xde, 0x5e, 0x84, 0x04, 0xc2, 0x42, 0xb3, 0x33, 0xec, 0x6c, 0x94, 0x14, 0xd0, 0x50, 0xb0, 0x30, 0xe8, 0x68, 0x90, 0x10, 0xce, 0x4e, 0xbf, 0x3f, 0xfe, 0x7e, 0xa0, 0x20, 0xdc, 0x5c, 0xa8, 0x28, 0xe0, 0x60, 0x88, 0x08, 0xc6, 0x46, 0xb7, 0x37, 0xf0, 0x70, 0x98, 0x18, 0xd4, 0x54, 0xaa, 0x2a, 0xe2, 0x62, 0x8a, 0x0a, 0xc8, 0x48, 0xb9, 0x39, 0xf4, 0x74, 0x9a, 0x1a, 0xd6, 0x56, 0xa2, 0x22, 0xdd, 0x5d, 0x82, 0x02, 0xc0, 0x40, 0xb1, 0x31, 0xea, 0x6a, 0x92, 0x12, 0xcf, 0x4f, 0xae, 0x2e, 0xe6, 0x66, 0x8e, 0x0e, 0xcc, 0x4c, 0xbd, 0x3d, 0xfc, 0x7c, 0x9e, 0x1e, 0xda, 0x5a, 0xa6, 0x26, 0xdf, 0x5f, 0x86, 0x06, 0xc4, 0x44, 0xb5, 0x35, 0xee, 0x6e, 0x96, 0x16, 0xd2, 0x52 }; /* ulaw -> alaw */ static char isdn_audio_ulaw_to_alaw[] = { 0xab, 0x55, 0xd5, 0x15, 0x95, 0x75, 0xf5, 0x35, 0xb5, 0x45, 0xc5, 0x05, 0x85, 0x65, 0xe5, 0x25, 0xa5, 0x5d, 0xdd, 0x1d, 0x9d, 0x7d, 0xfd, 0x3d, 0xbd, 0x4d, 0xcd, 0x0d, 0x8d, 0x6d, 0xed, 0x2d, 0xad, 0x51, 0xd1, 0x11, 0x91, 0x71, 0xf1, 0x31, 0xb1, 0x41, 0xc1, 0x01, 0x81, 0x61, 0xe1, 0x21, 0x59, 0xd9, 0x19, 0x99, 0x79, 0xf9, 0x39, 0xb9, 0x49, 0xc9, 0x09, 0x89, 0x69, 0xe9, 0x29, 0xa9, 0xd7, 0x17, 0x97, 0x77, 0xf7, 0x37, 0xb7, 0x47, 0xc7, 0x07, 0x87, 0x67, 0xe7, 0x27, 0xa7, 0xdf, 0x9f, 0x7f, 0xff, 0x3f, 0xbf, 0x4f, 0xcf, 0x0f, 0x8f, 0x6f, 0xef, 0x2f, 0x53, 0x13, 0x73, 0x33, 0xb3, 0x43, 0xc3, 0x03, 0x83, 0x63, 0xe3, 0x23, 0xa3, 0x5b, 0xdb, 0x1b, 0x9b, 0x7b, 0xfb, 0x3b, 0xbb, 0xbb, 0x4b, 0x4b, 0xcb, 0xcb, 0x0b, 0x0b, 0x8b, 0x8b, 0x6b, 0x6b, 0xeb, 0xeb, 0x2b, 0x2b, 0xab, 0x54, 0xd4, 0x14, 0x94, 0x74, 0xf4, 0x34, 0xb4, 0x44, 0xc4, 0x04, 0x84, 0x64, 0xe4, 0x24, 0xa4, 0x5c, 0xdc, 0x1c, 0x9c, 0x7c, 0xfc, 0x3c, 0xbc, 0x4c, 0xcc, 0x0c, 0x8c, 0x6c, 0xec, 0x2c, 0xac, 0x50, 0xd0, 0x10, 0x90, 0x70, 0xf0, 0x30, 0xb0, 0x40, 0xc0, 0x00, 0x80, 0x60, 0xe0, 0x20, 0x58, 0xd8, 0x18, 0x98, 0x78, 0xf8, 0x38, 0xb8, 0x48, 0xc8, 0x08, 0x88, 0x68, 0xe8, 0x28, 0xa8, 0xd6, 0x16, 0x96, 0x76, 0xf6, 0x36, 0xb6, 0x46, 0xc6, 0x06, 0x86, 0x66, 0xe6, 0x26, 0xa6, 0xde, 0x9e, 0x7e, 0xfe, 0x3e, 0xbe, 0x4e, 0xce, 0x0e, 0x8e, 0x6e, 0xee, 0x2e, 0x52, 0x12, 0x72, 0x32, 0xb2, 0x42, 0xc2, 0x02, 0x82, 0x62, 0xe2, 0x22, 0xa2, 0x5a, 0xda, 0x1a, 0x9a, 0x7a, 0xfa, 0x3a, 0xba, 0xba, 0x4a, 0x4a, 0xca, 0xca, 0x0a, 0x0a, 0x8a, 0x8a, 0x6a, 0x6a, 0xea, 0xea, 0x2a, 0x2a }; #define NCOEFF 8 /* number of frequencies to be analyzed */ #define DTMF_TRESH 4000 /* above this is dtmf */ #define SILENCE_TRESH 200 /* below this is silence */ #define AMP_BITS 9 /* bits per sample, reduced to avoid overflow */ #define LOGRP 0 #define HIGRP 1 /* For DTMF recognition: * 2 * cos(2 * PI * k / N) precalculated for all k */ static int cos2pik[NCOEFF] = { 55813, 53604, 51193, 48591, 38114, 33057, 25889, 18332 }; static char dtmf_matrix[4][4] = { {'1', '2', '3', 'A'}, {'4', '5', '6', 'B'}, {'7', '8', '9', 'C'}, {'*', '0', '#', 'D'} }; static inline void isdn_audio_tlookup(const u_char *table, u_char *buff, unsigned long n) { #ifdef __i386__ unsigned long d0, d1, d2, d3; __asm__ __volatile__( "cld\n" "1:\tlodsb\n\t" "xlatb\n\t" "stosb\n\t" "loop 1b\n\t" : "=&b"(d0), "=&c"(d1), "=&D"(d2), "=&S"(d3) : "0"((long) table), "1"(n), "2"((long) buff), "3"((long) buff) : "memory", "ax"); #else while (n--) *buff = table[*(unsigned char *)buff], buff++; #endif } void isdn_audio_ulaw2alaw(unsigned char *buff, unsigned long len) { isdn_audio_tlookup(isdn_audio_ulaw_to_alaw, buff, len); } void isdn_audio_alaw2ulaw(unsigned char *buff, unsigned long len) { isdn_audio_tlookup(isdn_audio_alaw_to_ulaw, buff, len); } /* * linear <-> adpcm conversion stuff * Most parts from the mgetty-package. * (C) by Gert Doering and Klaus Weidner * Used by permission of Gert Doering */ #define ZEROTRAP /* turn on the trap as per the MIL-STD */ #undef ZEROTRAP #define BIAS 0x84 /* define the add-in bias for 16 bit samples */ #define CLIP 32635 static unsigned char isdn_audio_linear2ulaw(int sample) { static int exp_lut[256] = { 0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 }; int sign, exponent, mantissa; unsigned char ulawbyte; /* Get the sample into sign-magnitude. */ sign = (sample >> 8) & 0x80; /* set aside the sign */ if (sign != 0) sample = -sample; /* get magnitude */ if (sample > CLIP) sample = CLIP; /* clip the magnitude */ /* Convert from 16 bit linear to ulaw. */ sample = sample + BIAS; exponent = exp_lut[(sample >> 7) & 0xFF]; mantissa = (sample >> (exponent + 3)) & 0x0F; ulawbyte = ~(sign | (exponent << 4) | mantissa); #ifdef ZEROTRAP /* optional CCITT trap */ if (ulawbyte == 0) ulawbyte = 0x02; #endif return (ulawbyte); } static int Mx[3][8] = { {0x3800, 0x5600, 0, 0, 0, 0, 0, 0}, {0x399a, 0x3a9f, 0x4d14, 0x6607, 0, 0, 0, 0}, {0x3556, 0x3556, 0x399A, 0x3A9F, 0x4200, 0x4D14, 0x6607, 0x6607}, }; static int bitmask[9] = { 0, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff }; static int isdn_audio_get_bits(adpcm_state * s, unsigned char **in, int *len) { while (s->nleft < s->nbits) { int d = *((*in)++); (*len)--; s->word = (s->word << 8) | d; s->nleft += 8; } s->nleft -= s->nbits; return (s->word >> s->nleft) & bitmask[s->nbits]; } static void isdn_audio_put_bits(int data, int nbits, adpcm_state * s, unsigned char **out, int *len) { s->word = (s->word << nbits) | (data & bitmask[nbits]); s->nleft += nbits; while (s->nleft >= 8) { int d = (s->word >> (s->nleft - 8)); *(out[0]++) = d & 255; (*len)++; s->nleft -= 8; } } adpcm_state * isdn_audio_adpcm_init(adpcm_state * s, int nbits) { if (!s) s = (adpcm_state *) kmalloc(sizeof(adpcm_state), GFP_ATOMIC); if (s) { s->a = 0; s->d = 5; s->word = 0; s->nleft = 0; s->nbits = nbits; } return s; } dtmf_state * isdn_audio_dtmf_init(dtmf_state * s) { if (!s) s = (dtmf_state *) kmalloc(sizeof(dtmf_state), GFP_ATOMIC); if (s) { s->idx = 0; s->last = ' '; } return s; } /* * Decompression of adpcm data to a/u-law * */ int isdn_audio_adpcm2xlaw(adpcm_state * s, int fmt, unsigned char *in, unsigned char *out, int len) { int a = s->a; int d = s->d; int nbits = s->nbits; int olen = 0; while (len) { int e = isdn_audio_get_bits(s, &in, &len); int sign; if (nbits == 4 && e == 0) d = 4; sign = (e >> (nbits - 1)) ? -1 : 1; e &= bitmask[nbits - 1]; a += sign * ((e << 1) + 1) * d >> 1; if (d & 1) a++; if (fmt) *out++ = isdn_audio_ulaw_to_alaw[ isdn_audio_linear2ulaw(a << 2)]; else *out++ = isdn_audio_linear2ulaw(a << 2); olen++; d = (d * Mx[nbits - 2][e] + 0x2000) >> 14; if (d < 5) d = 5; } s->a = a; s->d = d; return olen; } int isdn_audio_2adpcm_flush(adpcm_state * s, unsigned char *out) { int olen = 0; if (s->nleft) isdn_audio_put_bits(0, 8 - s->nleft, s, &out, &olen); return olen; } int isdn_audio_xlaw2adpcm(adpcm_state * s, int fmt, unsigned char *in, unsigned char *out, int len) { int a = s->a; int d = s->d; int nbits = s->nbits; int olen = 0; while (len--) { int e = 0, nmax = 1 << (nbits - 1); int sign, delta; if (fmt) delta = (isdn_audio_alaw_to_s16[*in++] >> 2) - a; else delta = (isdn_audio_ulaw_to_s16[*in++] >> 2) - a; if (delta < 0) { e = nmax; delta = -delta; } while (--nmax && delta > d) { delta -= d; e++; } if (nbits == 4 && ((e & 0x0f) == 0)) e = 8; isdn_audio_put_bits(e, nbits, s, &out, &olen); sign = (e >> (nbits - 1)) ? -1 : 1; e &= bitmask[nbits - 1]; a += sign * ((e << 1) + 1) * d >> 1; if (d & 1) a++; d = (d * Mx[nbits - 2][e] + 0x2000) >> 14; if (d < 5) d = 5; } s->a = a; s->d = d; return olen; } /* * Goertzel algorithm. * See http://ptolemy.eecs.berkeley.edu/~pino/Ptolemy/papers/96/dtmf_ict/ * for more info. * Result is stored into an sk_buff and queued up for later * evaluation. */ static void isdn_audio_goertzel(int *sample, modem_info * info) { int sk, sk1, sk2; int k, n; struct sk_buff *skb; int *result; skb = dev_alloc_skb(sizeof(int) * NCOEFF); if (!skb) { printk(KERN_WARNING "isdn_audio: Could not alloc DTMF result for ttyI%d\n", info->line); return; } result = (int *) skb_put(skb, sizeof(int) * NCOEFF); for (k = 0; k < NCOEFF; k++) { sk = sk1 = sk2 = 0; for (n = 0; n < DTMF_NPOINTS; n++) { sk = sample[n] + ((cos2pik[k] * sk1) >> 15) - sk2; sk2 = sk1; sk1 = sk; } /* Avoid overflows */ sk >>= 1; sk2 >>= 1; /* compute |X(k)|**2 */ /* report overflows. This should not happen. */ /* Comment this out if desired */ if (sk < -32768 || sk > 32767) printk(KERN_DEBUG "isdn_audio: dtmf goertzel overflow, sk=%d\n", sk); if (sk2 < -32768 || sk2 > 32767) printk(KERN_DEBUG "isdn_audio: dtmf goertzel overflow, sk2=%d\n", sk2); result[k] = ((sk * sk) >> AMP_BITS) - ((((cos2pik[k] * sk) >> 15) * sk2) >> AMP_BITS) + ((sk2 * sk2) >> AMP_BITS); } skb_queue_tail(&info->dtmf_queue, skb); isdn_timer_ctrl(ISDN_TIMER_MODEMREAD, 1); } void isdn_audio_eval_dtmf(modem_info * info) { struct sk_buff *skb; int *result; dtmf_state *s; int silence; int i; int di; int ch; unsigned long flags; int grp[2]; char what; char *p; int thresh; while ((skb = skb_dequeue(&info->dtmf_queue))) { result = (int *) skb->data; s = info->dtmf_state; grp[LOGRP] = grp[HIGRP] = -1; silence = 0; thresh = 0; for (i = 0; i < NCOEFF; i++) { if (result[i] > DTMF_TRESH) { if (result[i] > thresh) thresh = result[i]; } else if (result[i] < SILENCE_TRESH) silence++; } if (silence == NCOEFF) what = ' '; else { if (thresh > 0) { thresh = thresh >> 4; /* touchtones must match within 12 dB */ for (i = 0; i < NCOEFF; i++) { if (result[i] < thresh) continue; /* ignore */ /* good level found. This is allowed only one time per group */ if (i < NCOEFF / 2) { /* lowgroup*/ if (grp[LOGRP] >= 0) { // Bad. Another tone found. */ grp[LOGRP] = -1; break; } else grp[LOGRP] = i; } else { /* higroup */ if (grp[HIGRP] >= 0) { // Bad. Another tone found. */ grp[HIGRP] = -1; break; } else grp[HIGRP] = i - NCOEFF/2; } } if ((grp[LOGRP] >= 0) && (grp[HIGRP] >= 0)) { what = dtmf_matrix[grp[LOGRP]][grp[HIGRP]]; if (s->last != ' ' && s->last != '.') s->last = what; /* min. 1 non-DTMF between DTMF */ } else what = '.'; } else what = '.'; } if ((what != s->last) && (what != ' ') && (what != '.')) { printk(KERN_DEBUG "dtmf: tt='%c'\n", what); p = skb->data; *p++ = 0x10; *p = what; skb_trim(skb, 2); if (skb_headroom(skb) < sizeof(isdn_audio_skb)) { printk(KERN_WARNING "isdn_audio: insufficient skb_headroom, dropping\n"); kfree_skb(skb); return; } ISDN_AUDIO_SKB_DLECOUNT(skb) = 0; ISDN_AUDIO_SKB_LOCK(skb) = 0; save_flags(flags); cli(); di = info->isdn_driver; ch = info->isdn_channel; __skb_queue_tail(&dev->drv[di]->rpqueue[ch], skb); dev->drv[di]->rcvcount[ch] += 2; restore_flags(flags); /* Schedule dequeuing */ if ((dev->modempoll) && (info->rcvsched)) isdn_timer_ctrl(ISDN_TIMER_MODEMREAD, 1); wake_up_interruptible(&dev->drv[di]->rcv_waitq[ch]); } else kfree_skb(skb); s->last = what; } } /* * Decode DTMF tones, queue result in separate sk_buf for * later examination. * Parameters: * s = pointer to state-struct. * buf = input audio data * len = size of audio data. * fmt = audio data format (0 = ulaw, 1 = alaw) */ void isdn_audio_calc_dtmf(modem_info * info, unsigned char *buf, int len, int fmt) { dtmf_state *s = info->dtmf_state; int i; int c; while (len) { c = DTMF_NPOINTS - s->idx; if (c > len) c = len; if (c <= 0) break; for (i = 0; i < c; i++) { if (fmt) s->buf[s->idx++] = isdn_audio_alaw_to_s16[*buf++] >> (15 - AMP_BITS); else s->buf[s->idx++] = isdn_audio_ulaw_to_s16[*buf++] >> (15 - AMP_BITS); } if (s->idx == DTMF_NPOINTS) { isdn_audio_goertzel(s->buf, info); s->idx = 0; } len -= c; } } silence_state * isdn_audio_silence_init(silence_state * s) { if (!s) s = (silence_state *) kmalloc(sizeof(silence_state), GFP_ATOMIC); if (s) { s->idx = 0; s->state = 0; } return s; } void isdn_audio_calc_silence(modem_info * info, unsigned char *buf, int len, int fmt) { silence_state *s = info->silence_state; int i; signed char c; if (!info->emu.vpar[1]) return; for (i = 0; i < len; i++) { if (fmt) c = isdn_audio_alaw_to_ulaw[*buf++]; else c = *buf++; if (c > 0) c -= 128; c = abs(c); if (c > (info->emu.vpar[1] * 4)) { s->idx = 0; s->state = 1; } else { if (s->idx < 210000) s->idx++; } } } void isdn_audio_put_dle_code(modem_info * info, u_char code) { struct sk_buff *skb; unsigned long flags; int di; int ch; char *p; skb = dev_alloc_skb(2); if (!skb) { printk(KERN_WARNING "isdn_audio: Could not alloc skb for ttyI%d\n", info->line); return; } p = (char *) skb_put(skb, 2); p[0] = 0x10; p[1] = code; if (skb_headroom(skb) < sizeof(isdn_audio_skb)) { printk(KERN_WARNING "isdn_audio: insufficient skb_headroom, dropping\n"); kfree_skb(skb); return; } ISDN_AUDIO_SKB_DLECOUNT(skb) = 0; ISDN_AUDIO_SKB_LOCK(skb) = 0; save_flags(flags); cli(); di = info->isdn_driver; ch = info->isdn_channel; __skb_queue_tail(&dev->drv[di]->rpqueue[ch], skb); dev->drv[di]->rcvcount[ch] += 2; restore_flags(flags); /* Schedule dequeuing */ if ((dev->modempoll) && (info->rcvsched)) isdn_timer_ctrl(ISDN_TIMER_MODEMREAD, 1); wake_up_interruptible(&dev->drv[di]->rcv_waitq[ch]); } void isdn_audio_eval_silence(modem_info * info) { silence_state *s = info->silence_state; char what; what = ' '; if (s->idx > (info->emu.vpar[2] * 800)) { s->idx = 0; if (!s->state) { /* silence from beginning of rec */ what = 's'; } else { what = 'q'; } } if ((what == 's') || (what == 'q')) { printk(KERN_DEBUG "ttyI%d: %s\n", info->line, (what=='s') ? "silence":"quiet"); isdn_audio_put_dle_code(info, what); } }