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
|
/*
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.
*/
#include "dsp/gain_processor.h"
#include <algorithm>
#include <cmath>
#include "base/constants_and_types.h"
#include "dsp/gain.h"
namespace vraudio {
// Delegate default constructor.
GainProcessor::GainProcessor() : current_gain_(0.0f), is_initialized_(false) {}
GainProcessor::GainProcessor(float initial_gain)
: current_gain_(initial_gain), is_initialized_(true) {}
void GainProcessor::ApplyGain(float target_gain,
const AudioBuffer::Channel& input,
AudioBuffer::Channel* output,
bool accumulate_output) {
DCHECK(output);
if (!is_initialized_) {
Reset(target_gain);
}
// Check buffer length.
const size_t input_length = input.size();
DCHECK_GT(input_length, 0U);
DCHECK_EQ(input_length, output->size());
// Index for where to stop interpolating.
size_t ramp_length =
static_cast<size_t>(std::abs(target_gain - current_gain_) *
static_cast<float>(kUnitRampLength));
// Check if there is a new gain value.
if (ramp_length > 0) {
// Apply gain ramp to buffer.
current_gain_ = LinearGainRamp(ramp_length, current_gain_, target_gain,
input, output, accumulate_output);
} else {
// No ramping needed.
current_gain_ = target_gain;
}
// Apply constant gain to the rest of the buffer.
if (ramp_length < input_length) {
if (IsGainNearZero(current_gain_)) {
// Skip processing if the gain is zero.
if (!accumulate_output) {
// Directly fill the remaining output with zeros.
std::fill(output->begin() + ramp_length, output->end(), 0.0f);
}
return;
} else if (IsGainNearUnity(current_gain_) && !accumulate_output) {
// Skip processing if the gain is unity.
if (&input != output) {
// Directly copy the remaining input samples into output.
std::copy(input.begin() + ramp_length, input.end(),
output->begin() + ramp_length);
}
return;
}
ConstantGain(ramp_length, current_gain_, input, output, accumulate_output);
}
}
float GainProcessor::GetGain() const { return current_gain_; }
void GainProcessor::Reset(float gain) {
current_gain_ = gain;
is_initialized_ = true;
}
} // namespace vraudio
|
