diff options
Diffstat (limited to 'drivers/isdn/i4l/isdn_audio.h')
| -rw-r--r-- | drivers/isdn/i4l/isdn_audio.h | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/isdn/i4l/isdn_audio.h b/drivers/isdn/i4l/isdn_audio.h new file mode 100644 index 00000000..013c3582 --- /dev/null +++ b/drivers/isdn/i4l/isdn_audio.h @@ -0,0 +1,44 @@ +/* $Id: isdn_audio.h,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) + * + * This software may be used and distributed according to the terms + * of the GNU General Public License, incorporated herein by reference. + * + */ + +#define DTMF_NPOINTS 205 /* Number of samples for DTMF recognition */ +typedef struct adpcm_state { + int a; + int d; + int word; + int nleft; + int nbits; +} adpcm_state; + +typedef struct dtmf_state { + char last; + char llast; + int idx; + int buf[DTMF_NPOINTS]; +} dtmf_state; + +typedef struct silence_state { + int state; + unsigned int idx; +} silence_state; + +extern void isdn_audio_ulaw2alaw(unsigned char *, unsigned long); +extern void isdn_audio_alaw2ulaw(unsigned char *, unsigned long); +extern adpcm_state *isdn_audio_adpcm_init(adpcm_state *, int); +extern int isdn_audio_adpcm2xlaw(adpcm_state *, int, unsigned char *, unsigned char *, int); +extern int isdn_audio_xlaw2adpcm(adpcm_state *, int, unsigned char *, unsigned char *, int); +extern void isdn_audio_calc_dtmf(modem_info *, unsigned char *, int, int); +extern void isdn_audio_eval_dtmf(modem_info *); +dtmf_state *isdn_audio_dtmf_init(dtmf_state *); +extern void isdn_audio_calc_silence(modem_info *, unsigned char *, int, int); +extern void isdn_audio_eval_silence(modem_info *); +silence_state *isdn_audio_silence_init(silence_state *); +extern void isdn_audio_put_dle_code(modem_info *, u_char); |