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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/drivers/isdn/i4l/isdn_audio.h
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/* $Id: isdn_audio.h,v 1.1.2.2 2004/01/12 22:37:18 keil Exp $

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 *

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 * Linux ISDN subsystem, audio conversion and compression (linklevel).

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 *

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 * Copyright 1994-1999 by Fritz Elfert ([email protected])

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 *

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 * This software may be used and distributed according to the terms

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 * of the GNU General Public License, incorporated herein by reference.

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 *

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 */

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#define DTMF_NPOINTS 205        /* Number of samples for DTMF recognition */

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typedef struct adpcm_state {

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	int a;

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	int d;

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	int word;

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	int nleft;

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	int nbits;

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} adpcm_state;

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typedef struct dtmf_state {

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	char last;

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	char llast;

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	int idx;

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	int buf[DTMF_NPOINTS];

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} dtmf_state;

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typedef struct silence_state {

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	int state;

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	unsigned int idx;

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} silence_state;

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extern void isdn_audio_ulaw2alaw(unsigned char *, unsigned long);

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extern void isdn_audio_alaw2ulaw(unsigned char *, unsigned long);

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extern adpcm_state *isdn_audio_adpcm_init(adpcm_state *, int);

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extern int isdn_audio_adpcm2xlaw(adpcm_state *, int, unsigned char *, unsigned char *, int);

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extern int isdn_audio_xlaw2adpcm(adpcm_state *, int, unsigned char *, unsigned char *, int);

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extern void isdn_audio_calc_dtmf(modem_info *, unsigned char *, int, int);

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extern void isdn_audio_eval_dtmf(modem_info *);

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dtmf_state *isdn_audio_dtmf_init(dtmf_state *);

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extern void isdn_audio_calc_silence(modem_info *, unsigned char *, int, int);

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extern void isdn_audio_eval_silence(modem_info *);

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silence_state *isdn_audio_silence_init(silence_state *);

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extern void isdn_audio_put_dle_code(modem_info *, u_char);

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