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/*
* Copyright (c) 2014 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 "webrtc/modules/audio_processing/intelligibility/intelligibility_utils.h"
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <algorithm>
#include <limits>
namespace webrtc {
namespace intelligibility {
namespace {
const float kMinFactor = 0.01f;
const float kMaxFactor = 100.f;
// Return |current| changed towards |target|, with the relative change being at
// most |limit|.
float UpdateFactor(float target, float current, float limit) {
float gain = target / (current + std::numeric_limits<float>::epsilon());
gain = std::min(std::max(gain, 1.f - limit), 1.f + limit);
return std::min(std::max(current * gain, kMinFactor), kMaxFactor);;
}
} // namespace
template<typename T>
PowerEstimator<T>::PowerEstimator(size_t num_freqs, float decay)
: power_(num_freqs, 0.f), decay_(decay) {}
template<typename T>
void PowerEstimator<T>::Step(const T* data) {
for (size_t i = 0; i < power_.size(); ++i) {
power_[i] = decay_ * power_[i] +
(1.f - decay_) * std::abs(data[i]) * std::abs(data[i]);
}
}
template class PowerEstimator<float>;
template class PowerEstimator<std::complex<float>>;
GainApplier::GainApplier(size_t freqs, float relative_change_limit)
: num_freqs_(freqs),
relative_change_limit_(relative_change_limit),
target_(freqs, 1.f),
current_(freqs, 1.f) {}
GainApplier::~GainApplier() {}
void GainApplier::Apply(const std::complex<float>* in_block,
std::complex<float>* out_block) {
for (size_t i = 0; i < num_freqs_; ++i) {
current_[i] = UpdateFactor(target_[i], current_[i], relative_change_limit_);
out_block[i] = sqrtf(fabsf(current_[i])) * in_block[i];
}
}
DelayBuffer::DelayBuffer(size_t delay, size_t num_channels)
: buffer_(num_channels, std::vector<float>(delay, 0.f)), read_index_(0u) {}
DelayBuffer::~DelayBuffer() {}
void DelayBuffer::Delay(float* const* data, size_t length) {
size_t sample_index = read_index_;
for (size_t i = 0u; i < buffer_.size(); ++i) {
sample_index = read_index_;
for (size_t j = 0u; j < length; ++j) {
float swap = data[i][j];
data[i][j] = buffer_[i][sample_index];
buffer_[i][sample_index] = swap;
if (++sample_index == buffer_.size()) {
sample_index = 0u;
}
}
}
read_index_ = sample_index;
}
} // namespace intelligibility
} // namespace webrtc
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