blob: be7c4977452ff967f199c6137690e0a065f8971a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
/*
Copyright 2018 Google Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS-IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#ifndef RESONANCE_AUDIO_DSP_DELAY_FILTER_H_
#define RESONANCE_AUDIO_DSP_DELAY_FILTER_H_
#include <algorithm>
#include <memory>
#include "base/audio_buffer.h"
namespace vraudio {
// Single channel delay line class. Delays input buffer data by a non-negative
// integer number of samples.
//
// This implementation is not thread safe. The ClearBuffer() and InsertData()
// functions should not be called by a seperate thread during GetDelayedData().
class DelayFilter {
public:
// Constructs a DelayFilter.
//
// @param max_delay_length Maximum number of samples the input should be
// delayed by.
// @param frames_per_buffer Number of frames in each processed buffer.
DelayFilter(size_t max_delay_length, size_t frames_per_buffer);
// Sets the maximum delay length. It will allocate more space in the
// |delay_line_| if the new |max_delay_length| is more than doubled.
//
// @param max_delay_length New maximum delay in samples.
void SetMaximumDelay(size_t max_delay_length);
// Returns the current length of the |delay_line_|.
size_t GetDelayBufferLength() const { return delay_line_->num_frames(); }
// Returns the current maximum delay applicable to input buffers.
size_t GetMaximumDelayLength() const { return max_delay_length_; }
// Sets all of the |delay_line_| samples to zero.
void ClearBuffer() { delay_line_->Clear(); }
// Copies an |AudioBuffer::Channel| of data to the delay line.
//
// @param input Input data.
void InsertData(const AudioBuffer::Channel& input);
// Fills an |AudioBuffer::Channel| with data delayed by a specified amount
// less than or equal to the delay line's set |max_delay_length_|.
//
// @param delay_samples Requested delay to the data extraced from the delay
// line. Must be less than or equal to |max_delay_length_|.
// @param buffer Pointer to the output data, i.e., delayed input data.
void GetDelayedData(size_t delay_samples, AudioBuffer::Channel* buffer);
private:
// Maximum length of the delay to be applied (in samples).
size_t max_delay_length_;
// Number of frames in each AudioBuffer input/output.
size_t frames_per_buffer_;
// The delay line holding all of the delayed samples.
std::unique_ptr<AudioBuffer> delay_line_;
// Position in the delay line to begin writing to.
size_t write_cursor_;
};
} // namespace vraudio
#endif // RESONANCE_AUDIO_DSP_DELAY_FILTER_H_
|
