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/*
* Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/audio_mixer/gain_change_calculator.h"
#include <math.h>
#include <cstdlib>
#include <vector>
#include "rtc_base/checks.h"
namespace webrtc {
namespace {
constexpr int16_t kReliabilityThreshold = 100;
} // namespace
float GainChangeCalculator::CalculateGainChange(
rtc::ArrayView<const int16_t> in,
rtc::ArrayView<const int16_t> out) {
RTC_DCHECK_EQ(in.size(), out.size());
std::vector<float> gain(in.size());
CalculateGain(in, out, gain);
return CalculateDifferences(gain);
}
float GainChangeCalculator::LatestGain() const {
return last_reliable_gain_;
}
void GainChangeCalculator::CalculateGain(rtc::ArrayView<const int16_t> in,
rtc::ArrayView<const int16_t> out,
rtc::ArrayView<float> gain) {
RTC_DCHECK_EQ(in.size(), out.size());
RTC_DCHECK_EQ(in.size(), gain.size());
for (size_t i = 0; i < in.size(); ++i) {
if (std::abs(in[i]) >= kReliabilityThreshold) {
last_reliable_gain_ = out[i] / static_cast<float>(in[i]);
}
gain[i] = last_reliable_gain_;
}
}
float GainChangeCalculator::CalculateDifferences(
rtc::ArrayView<const float> values) {
float res = 0;
for (float f : values) {
res += fabs(f - last_value_);
last_value_ = f;
}
return res;
}
} // namespace webrtc