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| 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 "webrtc/modules/audio_processing/aec3/erl_estimator.h" |
| 12 |
| 13 #include <algorithm> |
| 14 |
| 15 namespace webrtc { |
| 16 |
| 17 namespace { |
| 18 |
| 19 constexpr float kMinErl = 0.01f; |
| 20 constexpr float kMaxErl = 1000.f; |
| 21 |
| 22 } // namespace |
| 23 |
| 24 ErlEstimator::ErlEstimator() { |
| 25 erl_.fill(kMaxErl); |
| 26 hold_counters_.fill(0); |
| 27 } |
| 28 |
| 29 ErlEstimator::~ErlEstimator() = default; |
| 30 |
| 31 void ErlEstimator::Update( |
| 32 const std::array<float, kFftLengthBy2Plus1>& render_spectrum, |
| 33 const std::array<float, kFftLengthBy2Plus1>& capture_spectrum) { |
| 34 const auto& X2 = render_spectrum; |
| 35 const auto& Y2 = capture_spectrum; |
| 36 |
| 37 // Corresponds to WGN of power -46 dBFS. |
| 38 constexpr float kX2Min = 44015068.0f; |
| 39 |
| 40 // Update the estimates in a maximum statistics manner. |
| 41 for (size_t k = 1; k < kFftLengthBy2; ++k) { |
| 42 if (X2[k] > kX2Min) { |
| 43 const float new_erl = Y2[k] / X2[k]; |
| 44 if (new_erl < erl_[k]) { |
| 45 hold_counters_[k - 1] = 1000; |
| 46 erl_[k] += 0.1 * (new_erl - erl_[k]); |
| 47 erl_[k] = std::max(erl_[k], kMinErl); |
| 48 } |
| 49 } |
| 50 } |
| 51 |
| 52 std::for_each(hold_counters_.begin(), hold_counters_.end(), |
| 53 [](int& a) { --a; }); |
| 54 std::transform(hold_counters_.begin(), hold_counters_.end(), erl_.begin() + 1, |
| 55 erl_.begin() + 1, [](int a, float b) { |
| 56 return a > 0 ? b : std::min(kMaxErl, 2.f * b); |
| 57 }); |
| 58 |
| 59 erl_[0] = erl_[1]; |
| 60 erl_[kFftLengthBy2] = erl_[kFftLengthBy2 - 1]; |
| 61 } |
| 62 |
| 63 } // namespace webrtc |
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