blob: 013c3582e0d19f3f813fb8712d3f47d1ef345374 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* $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 */
13typedef struct adpcm_state {
14 int a;
15 int d;
16 int word;
17 int nleft;
18 int nbits;
19} adpcm_state;
20
21typedef struct dtmf_state {
22 char last;
23 char llast;
24 int idx;
25 int buf[DTMF_NPOINTS];
26} dtmf_state;
27
28typedef struct silence_state {
29 int state;
30 unsigned int idx;
31} silence_state;
32
33extern void isdn_audio_ulaw2alaw(unsigned char *, unsigned long);
34extern void isdn_audio_alaw2ulaw(unsigned char *, unsigned long);
35extern adpcm_state *isdn_audio_adpcm_init(adpcm_state *, int);
36extern int isdn_audio_adpcm2xlaw(adpcm_state *, int, unsigned char *, unsigned char *, int);
37extern int isdn_audio_xlaw2adpcm(adpcm_state *, int, unsigned char *, unsigned char *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070038extern void isdn_audio_calc_dtmf(modem_info *, unsigned char *, int, int);
39extern void isdn_audio_eval_dtmf(modem_info *);
40dtmf_state *isdn_audio_dtmf_init(dtmf_state *);
41extern void isdn_audio_calc_silence(modem_info *, unsigned char *, int, int);
42extern void isdn_audio_eval_silence(modem_info *);
43silence_state *isdn_audio_silence_init(silence_state *);
44extern void isdn_audio_put_dle_code(modem_info *, u_char);