xref: /aosp_15_r20/external/webrtc/modules/audio_processing/echo_detector/mean_variance_estimator.cc (revision d9f758449e529ab9291ac668be2861e7a55c2422) 
1 /*
2  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include "modules/audio_processing/echo_detector/mean_variance_estimator.h"
12 
13 #include <math.h>
14 
15 #include "rtc_base/checks.h"
16 
17 namespace webrtc {
18 namespace {
19 
20 // Parameter controlling the adaptation speed.
21 constexpr float kAlpha = 0.001f;
22 
23 }  // namespace
24 
Update(float value)25 void MeanVarianceEstimator::Update(float value) {
26   mean_ = (1.f - kAlpha) * mean_ + kAlpha * value;
27   variance_ =
28       (1.f - kAlpha) * variance_ + kAlpha * (value - mean_) * (value - mean_);
29   RTC_DCHECK(isfinite(mean_));
30   RTC_DCHECK(isfinite(variance_));
31 }
32 
std_deviation() const33 float MeanVarianceEstimator::std_deviation() const {
34   RTC_DCHECK_GE(variance_, 0.f);
35   return sqrtf(variance_);
36 }
37 
mean() const38 float MeanVarianceEstimator::mean() const {
39   return mean_;
40 }
41 
Clear()42 void MeanVarianceEstimator::Clear() {
43   mean_ = 0.f;
44   variance_ = 0.f;
45 }
46 
47 }  // namespace webrtc
48