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