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1da177e4 LT |
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); | |
1da177e4 LT |
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); |