1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * OSLEC - A line echo canceller. This code is being developed |
4 | * against and partially complies with G168. Using code from SpanDSP |
5 | * |
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 Rowe |
10 | * |
11 | * All rights reserved. |
12 | */ |
13 | |
14 | #ifndef __OSLEC_H |
15 | #define __OSLEC_H |
16 | |
17 | /* Mask bits for the adaption mode */ |
18 | #define ECHO_CAN_USE_ADAPTION 0x01 |
19 | #define ECHO_CAN_USE_NLP 0x02 |
20 | #define ECHO_CAN_USE_CNG 0x04 |
21 | #define ECHO_CAN_USE_CLIP 0x08 |
22 | #define ECHO_CAN_USE_TX_HPF 0x10 |
23 | #define ECHO_CAN_USE_RX_HPF 0x20 |
24 | #define ECHO_CAN_DISABLE 0x40 |
25 | |
26 | /** |
27 | * oslec_state: G.168 echo canceller descriptor. |
28 | * |
29 | * This defines the working state for a line echo canceller. |
30 | */ |
31 | struct 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 be |
37 | * created. |
38 | */ |
39 | struct 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 | */ |
45 | void 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 | */ |
51 | void 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 | */ |
58 | void oslec_adaption_mode(struct oslec_state *ec, int adaption_mode); |
59 | |
60 | void 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 | */ |
70 | int16_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 | */ |
79 | int16_t oslec_hpf_tx(struct oslec_state *ec, int16_t tx); |
80 | |
81 | #endif /* __OSLEC_H */ |
82 | |