1 files changed, 173 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/aec3/refined_filter_update_gain.cc b/third_party/libwebrtc/modules/audio_processing/aec3/refined_filter_update_gain.cc
new file mode 100644
index 0000000000..8e391d6fa6
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/aec3/refined_filter_update_gain.cc
@@ -0,0 +1,173 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/audio_processing/aec3/refined_filter_update_gain.h"
+
+#include <algorithm>
+#include <functional>
+
+#include "modules/audio_processing/aec3/adaptive_fir_filter.h"
+#include "modules/audio_processing/aec3/aec3_common.h"
+#include "modules/audio_processing/aec3/echo_path_variability.h"
+#include "modules/audio_processing/aec3/fft_data.h"
+#include "modules/audio_processing/aec3/render_signal_analyzer.h"
+#include "modules/audio_processing/aec3/subtractor_output.h"
+#include "modules/audio_processing/logging/apm_data_dumper.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+namespace {
+
+constexpr float kHErrorInitial = 10000.f;
+constexpr int kPoorExcitationCounterInitial = 1000;
+
+}  // namespace
+
+std::atomic<int> RefinedFilterUpdateGain::instance_count_(0);
+
+RefinedFilterUpdateGain::RefinedFilterUpdateGain(
+    const EchoCanceller3Config::Filter::RefinedConfiguration& config,
+    size_t config_change_duration_blocks)
+    : data_dumper_(new ApmDataDumper(instance_count_.fetch_add(1) + 1)),
+      config_change_duration_blocks_(
+          static_cast<int>(config_change_duration_blocks)),
+      poor_excitation_counter_(kPoorExcitationCounterInitial) {
+  SetConfig(config, true);
+  H_error_.fill(kHErrorInitial);
+  RTC_DCHECK_LT(0, config_change_duration_blocks_);
+  one_by_config_change_duration_blocks_ = 1.f / config_change_duration_blocks_;
+}
+
+RefinedFilterUpdateGain::~RefinedFilterUpdateGain() {}
+
+void RefinedFilterUpdateGain::HandleEchoPathChange(
+    const EchoPathVariability& echo_path_variability) {
+  if (echo_path_variability.gain_change) {
+    // TODO(bugs.webrtc.org/9526) Handle gain changes.
+  }
+
+  if (echo_path_variability.delay_change !=
+      EchoPathVariability::DelayAdjustment::kNone) {
+    H_error_.fill(kHErrorInitial);
+  }
+
+  if (!echo_path_variability.gain_change) {
+    poor_excitation_counter_ = kPoorExcitationCounterInitial;
+    call_counter_ = 0;
+  }
+}
+
+void RefinedFilterUpdateGain::Compute(
+    const std::array<float, kFftLengthBy2Plus1>& render_power,
+    const RenderSignalAnalyzer& render_signal_analyzer,
+    const SubtractorOutput& subtractor_output,
+    rtc::ArrayView<const float> erl,
+    size_t size_partitions,
+    bool saturated_capture_signal,
+    bool disallow_leakage_diverged,
+    FftData* gain_fft) {
+  RTC_DCHECK(gain_fft);
+  // Introducing shorter notation to improve readability.
+  const FftData& E_refined = subtractor_output.E_refined;
+  const auto& E2_refined = subtractor_output.E2_refined;
+  const auto& E2_coarse = subtractor_output.E2_coarse;
+  FftData* G = gain_fft;
+  const auto& X2 = render_power;
+
+  ++call_counter_;
+
+  UpdateCurrentConfig();
+
+  if (render_signal_analyzer.PoorSignalExcitation()) {
+    poor_excitation_counter_ = 0;
+  }
+
+  // Do not update the filter if the render is not sufficiently excited.
+  if (++poor_excitation_counter_ < size_partitions ||
+      saturated_capture_signal || call_counter_ <= size_partitions) {
+    G->re.fill(0.f);
+    G->im.fill(0.f);
+  } else {
+    // Corresponds to WGN of power -39 dBFS.
+    std::array<float, kFftLengthBy2Plus1> mu;
+    // mu = H_error / (0.5* H_error* X2 + n * E2).
+    for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) {
+      if (X2[k] >= current_config_.noise_gate) {
+        mu[k] = H_error_[k] /
+                (0.5f * H_error_[k] * X2[k] + size_partitions * E2_refined[k]);
+      } else {
+        mu[k] = 0.f;
+      }
+    }
+
+    // Avoid updating the filter close to narrow bands in the render signals.
+    render_signal_analyzer.MaskRegionsAroundNarrowBands(&mu);
+
+    // H_error = H_error - 0.5 * mu * X2 * H_error.
+    for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) {
+      H_error_[k] -= 0.5f * mu[k] * X2[k] * H_error_[k];
+    }
+
+    // G = mu * E.
+    for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) {
+      G->re[k] = mu[k] * E_refined.re[k];
+      G->im[k] = mu[k] * E_refined.im[k];
+    }
+  }
+
+  // H_error = H_error + factor * erl.
+  for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) {
+    if (E2_refined[k] <= E2_coarse[k] || disallow_leakage_diverged) {
+      H_error_[k] += current_config_.leakage_converged * erl[k];
+    } else {
+      H_error_[k] += current_config_.leakage_diverged * erl[k];
+    }
+
+    H_error_[k] = std::max(H_error_[k], current_config_.error_floor);
+    H_error_[k] = std::min(H_error_[k], current_config_.error_ceil);
+  }
+
+  data_dumper_->DumpRaw("aec3_refined_gain_H_error", H_error_);
+}
+
+void RefinedFilterUpdateGain::UpdateCurrentConfig() {
+  RTC_DCHECK_GE(config_change_duration_blocks_, config_change_counter_);
+  if (config_change_counter_ > 0) {
+    if (--config_change_counter_ > 0) {
+      auto average = [](float from, float to, float from_weight) {
+        return from * from_weight + to * (1.f - from_weight);
+      };
+
+      float change_factor =
+          config_change_counter_ * one_by_config_change_duration_blocks_;
+
+      current_config_.leakage_converged =
+          average(old_target_config_.leakage_converged,
+                  target_config_.leakage_converged, change_factor);
+      current_config_.leakage_diverged =
+          average(old_target_config_.leakage_diverged,
+                  target_config_.leakage_diverged, change_factor);
+      current_config_.error_floor =
+          average(old_target_config_.error_floor, target_config_.error_floor,
+                  change_factor);
+      current_config_.error_ceil =
+          average(old_target_config_.error_ceil, target_config_.error_ceil,
+                  change_factor);
+      current_config_.noise_gate =
+          average(old_target_config_.noise_gate, target_config_.noise_gate,
+                  change_factor);
+    } else {
+      current_config_ = old_target_config_ = target_config_;
+    }
+  }
+  RTC_DCHECK_LE(0, config_change_counter_);
+}
+
+}  // namespace webrtc