diff options
Diffstat (limited to 'drivers/isdn/i4l/isdn_audio.c')
| -rw-r--r-- | drivers/isdn/i4l/isdn_audio.c | 710 |
1 files changed, 710 insertions, 0 deletions
diff --git a/drivers/isdn/i4l/isdn_audio.c b/drivers/isdn/i4l/isdn_audio.c new file mode 100644 index 0000000..fb350c5 --- /dev/null +++ b/drivers/isdn/i4l/isdn_audio.c @@ -0,0 +1,710 @@ +/* $Id: isdn_audio.c,v 1.1.2.2 2004/01/12 22:37:18 keil 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 <linux/isdn.h> +#include "isdn_audio.h" +#include "isdn_common.h" + +char *isdn_audio_revision = "$Revision: 1.1.2.2 $"; + +/* + * 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 = 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 = 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_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; + 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); + ISDN_AUDIO_SKB_DLECOUNT(skb) = 0; + ISDN_AUDIO_SKB_LOCK(skb) = 0; + di = info->isdn_driver; + ch = info->isdn_channel; + __skb_queue_tail(&dev->drv[di]->rpqueue[ch], skb); + dev->drv[di]->rcvcount[ch] += 2; + /* 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 = 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; + 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; + ISDN_AUDIO_SKB_DLECOUNT(skb) = 0; + ISDN_AUDIO_SKB_LOCK(skb) = 0; + di = info->isdn_driver; + ch = info->isdn_channel; + __skb_queue_tail(&dev->drv[di]->rpqueue[ch], skb); + dev->drv[di]->rcvcount[ch] += 2; + /* 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); + } +} |
