95 строки
2.8 KiB
C
95 строки
2.8 KiB
C
/*
|
|
* OSLEC - A line echo canceller. This code is being developed
|
|
* against and partially complies with G168. Using code from SpanDSP
|
|
*
|
|
* Written by Steve Underwood <steveu@coppice.org>
|
|
* and David Rowe <david_at_rowetel_dot_com>
|
|
*
|
|
* Copyright (C) 2001 Steve Underwood and 2007-2008 David Rowe
|
|
*
|
|
* All rights reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2, as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*
|
|
*/
|
|
|
|
#ifndef __OSLEC_H
|
|
#define __OSLEC_H
|
|
|
|
/* Mask bits for the adaption mode */
|
|
#define ECHO_CAN_USE_ADAPTION 0x01
|
|
#define ECHO_CAN_USE_NLP 0x02
|
|
#define ECHO_CAN_USE_CNG 0x04
|
|
#define ECHO_CAN_USE_CLIP 0x08
|
|
#define ECHO_CAN_USE_TX_HPF 0x10
|
|
#define ECHO_CAN_USE_RX_HPF 0x20
|
|
#define ECHO_CAN_DISABLE 0x40
|
|
|
|
/**
|
|
* oslec_state: G.168 echo canceller descriptor.
|
|
*
|
|
* This defines the working state for a line echo canceller.
|
|
*/
|
|
struct oslec_state;
|
|
|
|
/**
|
|
* oslec_create - Create a voice echo canceller context.
|
|
* @len: The length of the canceller, in samples.
|
|
* @return: The new canceller context, or NULL if the canceller could not be
|
|
* created.
|
|
*/
|
|
struct oslec_state *oslec_create(int len, int adaption_mode);
|
|
|
|
/**
|
|
* oslec_free - Free a voice echo canceller context.
|
|
* @ec: The echo canceller context.
|
|
*/
|
|
void oslec_free(struct oslec_state *ec);
|
|
|
|
/**
|
|
* oslec_flush - Flush (reinitialise) a voice echo canceller context.
|
|
* @ec: The echo canceller context.
|
|
*/
|
|
void oslec_flush(struct oslec_state *ec);
|
|
|
|
/**
|
|
* oslec_adaption_mode - set the adaption mode of a voice echo canceller context.
|
|
* @ec The echo canceller context.
|
|
* @adaption_mode: The mode.
|
|
*/
|
|
void oslec_adaption_mode(struct oslec_state *ec, int adaption_mode);
|
|
|
|
void oslec_snapshot(struct oslec_state *ec);
|
|
|
|
/**
|
|
* oslec_update: Process a sample through a voice echo canceller.
|
|
* @ec: The echo canceller context.
|
|
* @tx: The transmitted audio sample.
|
|
* @rx: The received audio sample.
|
|
*
|
|
* The return value is the clean (echo cancelled) received sample.
|
|
*/
|
|
int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx);
|
|
|
|
/**
|
|
* oslec_hpf_tx: Process to high pass filter the tx signal.
|
|
* @ec: The echo canceller context.
|
|
* @tx: The transmitted auio sample.
|
|
*
|
|
* The return value is the HP filtered transmit sample, send this to your D/A.
|
|
*/
|
|
int16_t oslec_hpf_tx(struct oslec_state *ec, int16_t tx);
|
|
|
|
#endif /* __OSLEC_H */
|