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/*
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
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 "graph/gain_node.h"
#include <cmath>
#include "dsp/gain.h"
namespace vraudio {
GainNode::GainNode(SourceId source_id, size_t num_channels,
const AttenuationType& attenuation_type,
const SystemSettings& system_settings)
: num_channels_(num_channels),
attenuation_type_(attenuation_type),
gain_processors_(num_channels_),
system_settings_(system_settings),
output_buffer_(num_channels, system_settings.GetFramesPerBuffer()) {
DCHECK_GT(num_channels, 0U);
output_buffer_.set_source_id(source_id);
}
const AudioBuffer* GainNode::AudioProcess(const NodeInput& input) {
const AudioBuffer* input_buffer = input.GetSingleInput();
DCHECK(input_buffer);
DCHECK_EQ(input_buffer->num_channels(), num_channels_);
DCHECK_EQ(input_buffer->source_id(), output_buffer_.source_id());
const auto source_parameters =
system_settings_.GetSourceParameters(input_buffer->source_id());
if (source_parameters == nullptr) {
LOG(WARNING) << "Could not find source parameters";
return nullptr;
}
const float current_gain = gain_processors_[0].GetGain();
const float target_gain = source_parameters->attenuations[attenuation_type_];
if (IsGainNearZero(target_gain) && IsGainNearZero(current_gain)) {
// Make sure the gain processors are initialized.
for (size_t i = 0; i < num_channels_; ++i) {
gain_processors_[i].Reset(0.0f);
}
// Skip processing in case of zero gain.
return nullptr;
}
if (IsGainNearUnity(target_gain) && IsGainNearUnity(current_gain)) {
// Make sure the gain processors are initialized.
for (size_t i = 0; i < num_channels_; ++i) {
gain_processors_[i].Reset(1.0f);
}
// Skip processing in case of unity gain.
return input_buffer;
}
// Apply the gain to each input buffer channel.
for (size_t i = 0; i < num_channels_; ++i) {
gain_processors_[i].ApplyGain(target_gain, (*input_buffer)[i],
&output_buffer_[i],
false /* accumulate_output */);
}
return &output_buffer_;
}
} // namespace vraudio