blob: 310e4e9dd1da22c541ba3a0708b4a44fef4b05fb [file] [log] [blame]
/*
* Copyright (c) 2018 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_processing/aec3/skew_estimator.h"
#include <algorithm>
#include <numeric>
namespace webrtc {
SkewEstimator::SkewEstimator(size_t skew_history_size_log2)
: skew_history_size_log2_(static_cast<int>(skew_history_size_log2)),
skew_history_(1ULL << skew_history_size_log2_, 0) {}
SkewEstimator::~SkewEstimator() = default;
void SkewEstimator::Reset() {
skew_ = 0;
skew_sum_ = 0;
next_index_ = 0;
sufficient_skew_stored_ = false;
std::fill(skew_history_.begin(), skew_history_.end(), 0);
}
absl::optional<int> SkewEstimator::GetSkewFromCapture() {
--skew_;
skew_sum_ += skew_ - skew_history_[next_index_];
skew_history_[next_index_] = skew_;
if (++next_index_ == skew_history_.size()) {
next_index_ = 0;
sufficient_skew_stored_ = true;
}
const int bias = static_cast<int>(skew_history_.size()) >> 1;
const int average = (skew_sum_ + bias) >> skew_history_size_log2_;
return sufficient_skew_stored_ ? absl::optional<int>(average) : absl::nullopt;
}
} // namespace webrtc