| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* $Id: isdn_audio.h,v 1.1.2.2 2004/01/12 22:37:18 keil Exp $ |
| 2 | * |
| 3 | * Linux ISDN subsystem, audio conversion and compression (linklevel). |
| 4 | * |
| 5 | * Copyright 1994-1999 by Fritz Elfert (fritz@isdn4linux.de) |
| 6 | * |
| 7 | * This software may be used and distributed according to the terms |
| 8 | * of the GNU General Public License, incorporated herein by reference. |
| 9 | * |
| 10 | */ |
| 11 | |
| 12 | #define DTMF_NPOINTS 205 /* Number of samples for DTMF recognition */ |
| 13 | typedef struct adpcm_state { |
| 14 | int a; |
| 15 | int d; |
| 16 | int word; |
| 17 | int nleft; |
| 18 | int nbits; |
| 19 | } adpcm_state; |
| 20 | |
| 21 | typedef struct dtmf_state { |
| 22 | char last; |
| 23 | char llast; |
| 24 | int idx; |
| 25 | int buf[DTMF_NPOINTS]; |
| 26 | } dtmf_state; |
| 27 | |
| 28 | typedef struct silence_state { |
| 29 | int state; |
| 30 | unsigned int idx; |
| 31 | } silence_state; |
| 32 | |
| 33 | extern void isdn_audio_ulaw2alaw(unsigned char *, unsigned long); |
| 34 | extern void isdn_audio_alaw2ulaw(unsigned char *, unsigned long); |
| 35 | extern adpcm_state *isdn_audio_adpcm_init(adpcm_state *, int); |
| 36 | extern int isdn_audio_adpcm2xlaw(adpcm_state *, int, unsigned char *, unsigned char *, int); |
| 37 | extern int isdn_audio_xlaw2adpcm(adpcm_state *, int, unsigned char *, unsigned char *, int); |
| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | extern void isdn_audio_calc_dtmf(modem_info *, unsigned char *, int, int); |
| 39 | extern void isdn_audio_eval_dtmf(modem_info *); |
| 40 | dtmf_state *isdn_audio_dtmf_init(dtmf_state *); |
| 41 | extern void isdn_audio_calc_silence(modem_info *, unsigned char *, int, int); |
| 42 | extern void isdn_audio_eval_silence(modem_info *); |
| 43 | silence_state *isdn_audio_silence_init(silence_state *); |
| 44 | extern void isdn_audio_put_dle_code(modem_info *, u_char); |