1 /*
2 * Copyright (c) 2017 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/aec3/output_selector.h"
12
13 #include <algorithm>
14 #include <numeric>
15
16 #include "rtc_base/checks.h"
17
18 namespace webrtc {
19 namespace {
20
21 // Performs the transition between the signals in a smooth manner.
SmoothFrameTransition(bool from_y_to_e,rtc::ArrayView<const float> e,rtc::ArrayView<float> y)22 void SmoothFrameTransition(bool from_y_to_e,
23 rtc::ArrayView<const float> e,
24 rtc::ArrayView<float> y) {
25 RTC_DCHECK_LT(0u, e.size());
26 RTC_DCHECK_EQ(y.size(), e.size());
27
28 const float change_factor = (from_y_to_e ? 1.f : -1.f) / e.size();
29 float averaging = from_y_to_e ? 0.f : 1.f;
30 for (size_t k = 0; k < e.size(); ++k) {
31 y[k] += averaging * (e[k] - y[k]);
32 averaging += change_factor;
33 }
34 RTC_DCHECK_EQ(from_y_to_e ? 1.f : 0.f, averaging);
35 }
36
37 } // namespace
38
39 OutputSelector::OutputSelector() = default;
40
41 OutputSelector::~OutputSelector() = default;
42
FormLinearOutput(bool use_subtractor_output,rtc::ArrayView<const float> subtractor_output,rtc::ArrayView<float> capture)43 void OutputSelector::FormLinearOutput(
44 bool use_subtractor_output,
45 rtc::ArrayView<const float> subtractor_output,
46 rtc::ArrayView<float> capture) {
47 RTC_DCHECK_EQ(subtractor_output.size(), capture.size());
48 rtc::ArrayView<const float>& e_main = subtractor_output;
49 rtc::ArrayView<float> y = capture;
50
51 if (use_subtractor_output != use_subtractor_output_) {
52 use_subtractor_output_ = use_subtractor_output;
53 SmoothFrameTransition(use_subtractor_output_, e_main, y);
54 } else if (use_subtractor_output_) {
55 std::copy(e_main.begin(), e_main.end(), y.begin());
56 }
57 }
58
59 } // namespace webrtc
60