1 /*
2 * Copyright (c) 2019 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/subband_nearend_detector.h"
12
13 #include <numeric>
14
15 namespace webrtc {
SubbandNearendDetector(const EchoCanceller3Config::Suppressor::SubbandNearendDetection & config,size_t num_capture_channels)16 SubbandNearendDetector::SubbandNearendDetector(
17 const EchoCanceller3Config::Suppressor::SubbandNearendDetection& config,
18 size_t num_capture_channels)
19 : config_(config),
20 num_capture_channels_(num_capture_channels),
21 nearend_smoothers_(num_capture_channels_,
22 aec3::MovingAverage(kFftLengthBy2Plus1,
23 config_.nearend_average_blocks)),
24 one_over_subband_length1_(
25 1.f / (config_.subband1.high - config_.subband1.low + 1)),
26 one_over_subband_length2_(
27 1.f / (config_.subband2.high - config_.subband2.low + 1)) {}
28
Update(rtc::ArrayView<const std::array<float,kFftLengthBy2Plus1>> nearend_spectrum,rtc::ArrayView<const std::array<float,kFftLengthBy2Plus1>> residual_echo_spectrum,rtc::ArrayView<const std::array<float,kFftLengthBy2Plus1>> comfort_noise_spectrum,bool initial_state)29 void SubbandNearendDetector::Update(
30 rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
31 nearend_spectrum,
32 rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
33 residual_echo_spectrum,
34 rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
35 comfort_noise_spectrum,
36 bool initial_state) {
37 nearend_state_ = false;
38 for (size_t ch = 0; ch < num_capture_channels_; ++ch) {
39 const std::array<float, kFftLengthBy2Plus1>& noise =
40 comfort_noise_spectrum[ch];
41 std::array<float, kFftLengthBy2Plus1> nearend;
42 nearend_smoothers_[ch].Average(nearend_spectrum[ch], nearend);
43
44 // Noise power of the first region.
45 float noise_power =
46 std::accumulate(noise.begin() + config_.subband1.low,
47 noise.begin() + config_.subband1.high + 1, 0.f) *
48 one_over_subband_length1_;
49
50 // Nearend power of the first region.
51 float nearend_power_subband1 =
52 std::accumulate(nearend.begin() + config_.subband1.low,
53 nearend.begin() + config_.subband1.high + 1, 0.f) *
54 one_over_subband_length1_;
55
56 // Nearend power of the second region.
57 float nearend_power_subband2 =
58 std::accumulate(nearend.begin() + config_.subband2.low,
59 nearend.begin() + config_.subband2.high + 1, 0.f) *
60 one_over_subband_length2_;
61
62 // One channel is sufficient to trigger nearend state.
63 nearend_state_ =
64 nearend_state_ ||
65 (nearend_power_subband1 <
66 config_.nearend_threshold * nearend_power_subband2 &&
67 (nearend_power_subband1 > config_.snr_threshold * noise_power));
68 }
69 }
70 } // namespace webrtc
71