1 files changed, 103 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/aec3/coarse_filter_update_gain.cc b/third_party/libwebrtc/modules/audio_processing/aec3/coarse_filter_update_gain.cc
new file mode 100644
index 0000000000..f4fb74d20d
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/aec3/coarse_filter_update_gain.cc
@@ -0,0 +1,103 @@
+/*
+ *  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/coarse_filter_update_gain.h"
+
+#include <algorithm>
+#include <functional>
+
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+CoarseFilterUpdateGain::CoarseFilterUpdateGain(
+    const EchoCanceller3Config::Filter::CoarseConfiguration& config,
+    size_t config_change_duration_blocks)
+    : config_change_duration_blocks_(
+          static_cast<int>(config_change_duration_blocks)) {
+  SetConfig(config, true);
+  RTC_DCHECK_LT(0, config_change_duration_blocks_);
+  one_by_config_change_duration_blocks_ = 1.f / config_change_duration_blocks_;
+}
+
+void CoarseFilterUpdateGain::HandleEchoPathChange() {
+  poor_signal_excitation_counter_ = 0;
+  call_counter_ = 0;
+}
+
+void CoarseFilterUpdateGain::Compute(
+    const std::array<float, kFftLengthBy2Plus1>& render_power,
+    const RenderSignalAnalyzer& render_signal_analyzer,
+    const FftData& E_coarse,
+    size_t size_partitions,
+    bool saturated_capture_signal,
+    FftData* G) {
+  RTC_DCHECK(G);
+  ++call_counter_;
+
+  UpdateCurrentConfig();
+
+  if (render_signal_analyzer.PoorSignalExcitation()) {
+    poor_signal_excitation_counter_ = 0;
+  }
+
+  // Do not update the filter if the render is not sufficiently excited.
+  if (++poor_signal_excitation_counter_ < size_partitions ||
+      saturated_capture_signal || call_counter_ <= size_partitions) {
+    G->re.fill(0.f);
+    G->im.fill(0.f);
+    return;
+  }
+
+  // Compute mu.
+  std::array<float, kFftLengthBy2Plus1> mu;
+  const auto& X2 = render_power;
+  for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) {
+    if (X2[k] > current_config_.noise_gate) {
+      mu[k] = current_config_.rate / X2[k];
+    } else {
+      mu[k] = 0.f;
+    }
+  }
+
+  // Avoid updating the filter close to narrow bands in the render signals.
+  render_signal_analyzer.MaskRegionsAroundNarrowBands(&mu);
+
+  // G = mu * E * X2.
+  for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) {
+    G->re[k] = mu[k] * E_coarse.re[k];
+    G->im[k] = mu[k] * E_coarse.im[k];
+  }
+}
+
+void CoarseFilterUpdateGain::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_.rate =
+          average(old_target_config_.rate, target_config_.rate, 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