2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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.
11 #include "webrtc/base/exp_filter.h"
17 const float ExpFilter::kValueUndefined = -1.0f;
19 void ExpFilter::Reset(float alpha) {
21 filtered_ = kValueUndefined;
24 float ExpFilter::Apply(float exp, float sample) {
25 if (filtered_ == kValueUndefined) {
26 // Initialize filtered value.
28 } else if (exp == 1.0) {
29 filtered_ = alpha_ * filtered_ + (1 - alpha_) * sample;
31 float alpha = pow(alpha_, exp);
32 filtered_ = alpha * filtered_ + (1 - alpha) * sample;
34 if (max_ != kValueUndefined && filtered_ > max_) {
40 void ExpFilter::UpdateBase(float alpha) {