1/*
2Copyright 2018 Google Inc. All Rights Reserved.
3
4Licensed under the Apache License, Version 2.0 (the "License");
5you may not use this file except in compliance with the License.
6You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10Unless required by applicable law or agreed to in writing, software
11distributed under the License is distributed on an "AS-IS" BASIS,
12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13See the License for the specific language governing permissions and
14limitations under the License.
15*/
16
17#include "graph/gain_node.h"
18
19#include <cmath>
20
21
22#include "dsp/gain.h"
23
24namespace vraudio {
25
26GainNode::GainNode(SourceId source_id, size_t num_channels,
27 const AttenuationType& attenuation_type,
28 const SystemSettings& system_settings)
29 : num_channels_(num_channels),
30 attenuation_type_(attenuation_type),
31 gain_processors_(num_channels_),
32 system_settings_(system_settings),
33 output_buffer_(num_channels, system_settings.GetFramesPerBuffer()) {
34 DCHECK_GT(num_channels, 0U);
35 output_buffer_.set_source_id(source_id);
36}
37
38const AudioBuffer* GainNode::AudioProcess(const NodeInput& input) {
39
40
41 const AudioBuffer* input_buffer = input.GetSingleInput();
42 DCHECK(input_buffer);
43 DCHECK_EQ(input_buffer->num_channels(), num_channels_);
44 DCHECK_EQ(input_buffer->source_id(), output_buffer_.source_id());
45
46 const auto source_parameters =
47 system_settings_.GetSourceParameters(source_id: input_buffer->source_id());
48 if (source_parameters == nullptr) {
49 LOG(WARNING) << "Could not find source parameters";
50 return nullptr;
51 }
52
53 const float current_gain = gain_processors_[0].GetGain();
54 const float target_gain = source_parameters->attenuations[attenuation_type_];
55 if (IsGainNearZero(gain: target_gain) && IsGainNearZero(gain: current_gain)) {
56 // Make sure the gain processors are initialized.
57 for (size_t i = 0; i < num_channels_; ++i) {
58 gain_processors_[i].Reset(gain: 0.0f);
59 }
60 // Skip processing in case of zero gain.
61 return nullptr;
62 }
63 if (IsGainNearUnity(gain: target_gain) && IsGainNearUnity(gain: current_gain)) {
64 // Make sure the gain processors are initialized.
65 for (size_t i = 0; i < num_channels_; ++i) {
66 gain_processors_[i].Reset(gain: 1.0f);
67 }
68 // Skip processing in case of unity gain.
69 return input_buffer;
70 }
71
72 // Apply the gain to each input buffer channel.
73 for (size_t i = 0; i < num_channels_; ++i) {
74 gain_processors_[i].ApplyGain(target_gain, input: (*input_buffer)[i],
75 output: &output_buffer_[i],
76 accumulate_output: false /* accumulate_output */);
77 }
78
79 return &output_buffer_;
80}
81
82} // namespace vraudio
83

source code of qtmultimedia/src/3rdparty/resonance-audio/resonance_audio/graph/gain_node.cc