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
86
87
88
89
90
91
92
93
94
95
96
|
/*
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_GAIN_MIXER_H_
#define RESONANCE_AUDIO_DSP_GAIN_MIXER_H_
#include <memory>
#include <unordered_map>
#include <vector>
#include "base/audio_buffer.h"
#include "base/constants_and_types.h"
#include "dsp/gain_processor.h"
namespace vraudio {
class GainMixer {
public:
GainMixer(size_t num_channels, size_t frames_per_buffer);
// Adds a separately scaled version of each channel of the input buffer to the
// output buffer's corresponding channels.
//
// @param input Input buffer to be added.
// @param gains Gains to be applied to the buffers channels. Must be equal in
// length to the number of channels in |input|.
void AddInput(const AudioBuffer& input, const std::vector<float>& gains);
// Adds a single input channel to each of the output buffer's channels, with
// a separate gain applied to the input channel per output channel.
//
// @param input Input channel to be added.
// @param source_id Identifier corresponding to the input.
// @param gains Gains to be applied to the buffers channels. Must be equal in
// length to the number of channels in the output buffer.
void AddInputChannel(const AudioBuffer::Channel& input, SourceId source_id,
const std::vector<float>& gains);
// Returns a pointer to the accumulator.
//
// @return Pointer to the processed (mixed) output buffer, or nullptr if no
// input has been added to the accumulator.
const AudioBuffer* GetOutput() const;
// Resets the state of the accumulator.
void Reset();
private:
// Comprises one |GainProcessor| per channel of a source and a boolean to
// denote whether that source is active.
struct GainProcessors {
explicit GainProcessors(size_t num_channels);
// Bool to signify if a given source is still passing data to a processor.
bool processors_active;
// Scale and accumulation processors, one per channel for each source.
std::vector<GainProcessor> processors;
};
// Returns the |GainProcessor|s associated with a |source_id| (or creates
// one if needed) and sets the corresponding |processors_active| flag to true.
//
// @param source_id Identifier for a given input.
// @return The corresponding |ScalingAccumulators|.
std::vector<GainProcessor>* GetOrCreateProcessors(SourceId source_id);
// Number of channels.
const size_t num_channels_;
// Output buffer (accumulator).
AudioBuffer output_;
// Denotes whether the accumulator has processed any inputs or not.
bool is_empty_;
// Scale and accumulation processors, one per channel for each source.
std::unordered_map<SourceId, GainProcessors> source_gain_processors_;
};
} // namespace vraudio
#endif // RESONANCE_AUDIO_DSP_GAIN_MIXER_H_
|
