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17f8c114 TC |
1 | /* |
2 | * OSLEC - A line echo canceller. This code is being developed | |
3 | * against and partially complies with G168. Using code from SpanDSP | |
4 | * | |
5 | * Written by Steve Underwood <steveu@coppice.org> | |
6 | * and David Rowe <david_at_rowetel_dot_com> | |
7 | * | |
8 | * Copyright (C) 2001 Steve Underwood and 2007-2008 David Rowe | |
9 | * | |
10 | * All rights reserved. | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License version 2, as | |
14 | * published by the Free Software Foundation. | |
15 | * | |
16 | * This program is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | * GNU General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License | |
22 | * along with this program; if not, write to the Free Software | |
23 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
24 | * | |
25 | */ | |
26 | ||
27 | #ifndef __OSLEC_H | |
28 | #define __OSLEC_H | |
29 | ||
17f8c114 TC |
30 | /* Mask bits for the adaption mode */ |
31 | #define ECHO_CAN_USE_ADAPTION 0x01 | |
32 | #define ECHO_CAN_USE_NLP 0x02 | |
33 | #define ECHO_CAN_USE_CNG 0x04 | |
34 | #define ECHO_CAN_USE_CLIP 0x08 | |
35 | #define ECHO_CAN_USE_TX_HPF 0x10 | |
36 | #define ECHO_CAN_USE_RX_HPF 0x20 | |
37 | #define ECHO_CAN_DISABLE 0x40 | |
38 | ||
56791f0a GKH |
39 | /** |
40 | * oslec_state: G.168 echo canceller descriptor. | |
41 | * | |
42 | * This defines the working state for a line echo canceller. | |
43 | */ | |
9d8f2d5d | 44 | struct oslec_state; |
17f8c114 | 45 | |
56791f0a GKH |
46 | /** |
47 | * oslec_create - Create a voice echo canceller context. | |
48 | * @len: The length of the canceller, in samples. | |
49 | * @return: The new canceller context, or NULL if the canceller could not be | |
50 | * created. | |
51 | */ | |
9d8f2d5d | 52 | struct oslec_state *oslec_create(int len, int adaption_mode); |
17f8c114 | 53 | |
56791f0a GKH |
54 | /** |
55 | * oslec_free - Free a voice echo canceller context. | |
56 | * @ec: The echo canceller context. | |
57 | */ | |
9d8f2d5d | 58 | void oslec_free(struct oslec_state *ec); |
17f8c114 | 59 | |
56791f0a GKH |
60 | /** |
61 | * oslec_flush - Flush (reinitialise) a voice echo canceller context. | |
62 | * @ec: The echo canceller context. | |
63 | */ | |
9d8f2d5d | 64 | void oslec_flush(struct oslec_state *ec); |
17f8c114 | 65 | |
56791f0a GKH |
66 | /** |
67 | * oslec_adaption_mode - set the adaption mode of a voice echo canceller context. | |
68 | * @ec The echo canceller context. | |
69 | * @adaption_mode: The mode. | |
70 | */ | |
9d8f2d5d | 71 | void oslec_adaption_mode(struct oslec_state *ec, int adaption_mode); |
17f8c114 | 72 | |
9d8f2d5d | 73 | void oslec_snapshot(struct oslec_state *ec); |
17f8c114 | 74 | |
56791f0a GKH |
75 | /** |
76 | * oslec_update: Process a sample through a voice echo canceller. | |
77 | * @ec: The echo canceller context. | |
78 | * @tx: The transmitted audio sample. | |
79 | * @rx: The received audio sample. | |
80 | * | |
81 | * The return value is the clean (echo cancelled) received sample. | |
82 | */ | |
9d8f2d5d | 83 | int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx); |
17f8c114 | 84 | |
56791f0a GKH |
85 | /** |
86 | * oslec_hpf_tx: Process to high pass filter the tx signal. | |
87 | * @ec: The echo canceller context. | |
88 | * @tx: The transmitted auio sample. | |
89 | * | |
90 | * The return value is the HP filtered transmit sample, send this to your D/A. | |
91 | */ | |
9d8f2d5d | 92 | int16_t oslec_hpf_tx(struct oslec_state *ec, int16_t tx); |
17f8c114 | 93 | |
4460a860 | 94 | #endif /* __OSLEC_H */ |