1/*
2** Copyright 2011, The Android Open-Source Project
3**
4** Licensed under the Apache License, Version 2.0 (the "License");
5** you may not use this file except in compliance with the License.
6** You may obtain a copy of the License at
7**
8**     http://www.apache.org/licenses/LICENSE-2.0
9**
10** Unless required by applicable law or agreed to in writing, software
11** distributed under the License is distributed on an "AS IS" BASIS,
12** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13** See the License for the specific language governing permissions and
14** limitations under the License.
15*/
16
17#ifndef ANDROID_ECHO_REFERENCE_H
18#define ANDROID_ECHO_REFERENCE_H
19
20#include <stdint.h>
21#include <sys/time.h>
22
23__BEGIN_DECLS
24
25/* Buffer descriptor used by read() and write() methods, including the time stamp and delay. */
26struct echo_reference_buffer {
27    void *raw;                  // pointer to audio frame
28    size_t frame_count;         // number of frames in buffer
29    int32_t delay_ns;           // delay for this buffer (see comment below)
30    struct timespec time_stamp; // time stamp for this buffer (see comment below)
31                                // default ALSA gettimeofday() format
32};
33/**
34 * + as input:
35 *      - delay_ns is the delay introduced by playback buffers
36 *      - time_stamp is the time stamp corresponding to the delay calculation
37 * + as output:
38 *      unused
39 * when used for EchoReference::read():
40 * + as input:
41 *      - delay_ns is the delay introduced by capture buffers
42 *      - time_stamp is the time stamp corresponding to the delay calculation
43 * + as output:
44 *      - delay_ns is the delay between the returned frames and the capture time derived from
45 *      delay and time stamp indicated as input. This delay is to be communicated to the AEC.
46 *      - frame_count is updated with the actual number of frames returned
47 */
48
49struct echo_reference_itfe {
50    int (*read)(struct echo_reference_itfe *echo_reference, struct echo_reference_buffer *buffer);
51    int (*write)(struct echo_reference_itfe *echo_reference, struct echo_reference_buffer *buffer);
52};
53
54int create_echo_reference(audio_format_t rdFormat,
55                          uint32_t rdChannelCount,
56                          uint32_t rdSamplingRate,
57                          audio_format_t wrFormat,
58                          uint32_t wrChannelCount,
59                          uint32_t wrSamplingRate,
60                          struct echo_reference_itfe **);
61
62void release_echo_reference(struct echo_reference_itfe *echo_reference);
63
64__END_DECLS
65
66#endif // ANDROID_ECHO_REFERENCE_H
67