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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * OSLEC - A line echo canceller. This code is being developed4 * against and partially complies with G168. Using code from SpanDSP5 *6 * Written by Steve Underwood <steveu@coppice.org>7 * and David Rowe <david_at_rowetel_dot_com>8 *9 * Copyright (C) 2001 Steve Underwood and 2007-2008 David Rowe10 *11 * All rights reserved.12 */13 14#ifndef __OSLEC_H15#define __OSLEC_H16 17/* Mask bits for the adaption mode */18#define ECHO_CAN_USE_ADAPTION 0x0119#define ECHO_CAN_USE_NLP 0x0220#define ECHO_CAN_USE_CNG 0x0421#define ECHO_CAN_USE_CLIP 0x0822#define ECHO_CAN_USE_TX_HPF 0x1023#define ECHO_CAN_USE_RX_HPF 0x2024#define ECHO_CAN_DISABLE 0x4025 26/**27 * oslec_state: G.168 echo canceller descriptor.28 *29 * This defines the working state for a line echo canceller.30 */31struct oslec_state;32 33/**34 * oslec_create - Create a voice echo canceller context.35 * @len: The length of the canceller, in samples.36 * @return: The new canceller context, or NULL if the canceller could not be37 * created.38 */39struct oslec_state *oslec_create(int len, int adaption_mode);40 41/**42 * oslec_free - Free a voice echo canceller context.43 * @ec: The echo canceller context.44 */45void oslec_free(struct oslec_state *ec);46 47/**48 * oslec_flush - Flush (reinitialise) a voice echo canceller context.49 * @ec: The echo canceller context.50 */51void oslec_flush(struct oslec_state *ec);52 53/**54 * oslec_adaption_mode - set the adaption mode of a voice echo canceller context.55 * @ec The echo canceller context.56 * @adaption_mode: The mode.57 */58void oslec_adaption_mode(struct oslec_state *ec, int adaption_mode);59 60void oslec_snapshot(struct oslec_state *ec);61 62/**63 * oslec_update: Process a sample through a voice echo canceller.64 * @ec: The echo canceller context.65 * @tx: The transmitted audio sample.66 * @rx: The received audio sample.67 *68 * The return value is the clean (echo cancelled) received sample.69 */70int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx);71 72/**73 * oslec_hpf_tx: Process to high pass filter the tx signal.74 * @ec: The echo canceller context.75 * @tx: The transmitted auio sample.76 *77 * The return value is the HP filtered transmit sample, send this to your D/A.78 */79int16_t oslec_hpf_tx(struct oslec_state *ec, int16_t tx);80 81#endif /* __OSLEC_H */82