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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
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_mixer.h"
#include <cmath>
#include "base/logging.h"
namespace vraudio {
GainMixer::GainMixer(size_t num_channels, size_t frames_per_buffer)
: num_channels_(num_channels),
output_(num_channels_, frames_per_buffer),
is_empty_(false) {
DCHECK_NE(num_channels_, 0U);
Reset();
}
void GainMixer::AddInput(const AudioBuffer& input,
const std::vector<float>& gains) {
DCHECK_EQ(gains.size(), num_channels_);
DCHECK_EQ(input.num_channels(), num_channels_);
DCHECK_EQ(input.num_frames(), output_.num_frames());
auto* gain_processors = GetOrCreateProcessors(input.source_id());
// Accumulate the input buffers into the output buffer.
for (size_t i = 0; i < num_channels_; ++i) {
if (input[i].IsEnabled()) {
(*gain_processors)[i].ApplyGain(gains[i], input[i], &output_[i],
true /* accumulate_output */);
} else {
// Make sure the gain processor is initialized.
(*gain_processors)[i].Reset(gains[i]);
}
}
is_empty_ = false;
}
void GainMixer::AddInputChannel(const AudioBuffer::Channel& input,
SourceId source_id,
const std::vector<float>& gains) {
DCHECK_EQ(gains.size(), num_channels_);
DCHECK_EQ(input.size(), output_.num_frames());
auto* gain_processors = GetOrCreateProcessors(source_id);
// Accumulate the input buffers into the output buffer.
for (size_t i = 0; i < num_channels_; ++i) {
if (input.IsEnabled()) {
(*gain_processors)[i].ApplyGain(gains[i], input, &output_[i],
true /* accumulate_output */);
} else {
// Make sure the gain processor is initialized.
(*gain_processors)[i].Reset(gains[i]);
}
}
is_empty_ = false;
}
const AudioBuffer* GainMixer::GetOutput() const {
if (is_empty_) {
return nullptr;
}
return &output_;
}
void GainMixer::Reset() {
if (!is_empty_) {
// Delete the processors for sources which no longer exist.
for (auto it = source_gain_processors_.begin();
it != source_gain_processors_.end();
/* no increment */) {
if (it->second.processors_active) {
it->second.processors_active = false;
++it;
} else {
source_gain_processors_.erase(it++);
}
}
// Reset the output buffer.
output_.Clear();
}
is_empty_ = true;
}
GainMixer::GainProcessors::GainProcessors(size_t num_channels)
: processors_active(true), processors(num_channels) {}
std::vector<GainProcessor>* GainMixer::GetOrCreateProcessors(
SourceId source_id) {
// Attempt to find a |ScaleAndAccumulateProcessor| for the given |source_id|,
// if none can be found add one. In either case mark that the processor has
// been used so that it is not later deleted.
if (source_gain_processors_.find(source_id) ==
source_gain_processors_.end()) {
source_gain_processors_.insert({source_id, GainProcessors(num_channels_)});
}
source_gain_processors_.at(source_id).processors_active = true;
return &(source_gain_processors_.at(source_id).processors);
}
} // namespace vraudio
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