From 7f5175a4552db9af5cb5f15d307c5c0c690cf8f9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Per=20=C3=85hgren?= <peah@webrtc.org>
Date: Wed, 25 Jul 2018 16:30:54 +0200
Subject: [PATCH] AEC3: Corrected the filter adjustment during analog gain
 changes
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This CL corrects the way that the echo subtractor output is
adjusted during the adjustment of the adaptive filter when the
analog AGC gain changes.

The CL also ensures that the main adaptive filter is not updated
when this occurs.

Bug: webrtc:9561,chromium:867373
Change-Id: I636f936128f7d9f0d82ca4140b59f148eb35d6a4
Reviewed-on: https://webrtc-review.googlesource.com/90401
Commit-Queue: Per Åhgren <peah@webrtc.org>
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24101}
---
 modules/audio_processing/aec3/subtractor.cc   | 36 +++++++++++++++----
 .../audio_processing/aec3/subtractor_output.h | 18 ----------
 2 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/modules/audio_processing/aec3/subtractor.cc b/modules/audio_processing/aec3/subtractor.cc
index 787573aa16..d9ed8fd387 100644
--- a/modules/audio_processing/aec3/subtractor.cc
+++ b/modules/audio_processing/aec3/subtractor.cc
@@ -71,6 +71,18 @@ void PredictionError(const Aec3Fft& fft,
   }
 }
 
+void ScaleFilterOutput(rtc::ArrayView<const float> y,
+                       float factor,
+                       rtc::ArrayView<float> e,
+                       rtc::ArrayView<float> s) {
+  RTC_DCHECK_EQ(y.size(), e.size());
+  RTC_DCHECK_EQ(y.size(), s.size());
+  for (size_t k = 0; k < y.size(); ++k) {
+    s[k] *= factor;
+    e[k] = y[k] - s[k];
+  }
+}
+
 }  // namespace
 
 Subtractor::Subtractor(const EchoCanceller3Config& config,
@@ -157,29 +169,34 @@ void Subtractor::Process(const RenderBuffer& render_buffer,
   FftData S;
   FftData& G = S;
 
-  // Form the output of the main filter.
+  // Form the outputs of the main and shadow filters.
   main_filter_.Filter(render_buffer, &S);
   bool main_saturation = false;
   PredictionError(fft_, S, y, &e_main, &output->s_main,
                   adaptation_during_saturation_, &main_saturation);
-  fft_.ZeroPaddedFft(e_main, Aec3Fft::Window::kHanning, &E_main);
 
-  // Form the output of the shadow filter.
   shadow_filter_.Filter(render_buffer, &S);
   bool shadow_saturation = false;
   PredictionError(fft_, S, y, &e_shadow, nullptr, adaptation_during_saturation_,
                   &shadow_saturation);
-  fft_.ZeroPaddedFft(e_shadow, Aec3Fft::Window::kHanning, &E_shadow);
 
+  // Adjust the filter if needed.
+  bool main_filter_adjusted = false;
   if (enable_misadjustment_estimator_) {
     filter_misadjustment_estimator_.Update(e_main, y);
     if (filter_misadjustment_estimator_.IsAdjustmentNeeded()) {
       float scale = filter_misadjustment_estimator_.GetMisadjustment();
       main_filter_.ScaleFilter(scale);
-      output->ScaleOutputMainFilter(scale);
+      ScaleFilterOutput(y, scale, e_main, output->s_main);
       filter_misadjustment_estimator_.Reset();
+      main_filter_adjusted = true;
     }
   }
+
+  // Compute the FFts of the main and shadow filter outputs.
+  fft_.ZeroPaddedFft(e_main, Aec3Fft::Window::kHanning, &E_main);
+  fft_.ZeroPaddedFft(e_shadow, Aec3Fft::Window::kHanning, &E_shadow);
+
   // Compute spectra for future use.
   E_shadow.Spectrum(optimization_, output->E2_shadow);
   E_main.Spectrum(optimization_, output->E2_main);
@@ -187,8 +204,13 @@ void Subtractor::Process(const RenderBuffer& render_buffer,
   // Update the main filter.
   std::array<float, kFftLengthBy2Plus1> X2;
   render_buffer.SpectralSum(main_filter_.SizePartitions(), &X2);
-  G_main_.Compute(X2, render_signal_analyzer, *output, main_filter_,
-                  aec_state.SaturatedCapture() || main_saturation, &G);
+  if (!main_filter_adjusted) {
+    G_main_.Compute(X2, render_signal_analyzer, *output, main_filter_,
+                    aec_state.SaturatedCapture() || main_saturation, &G);
+  } else {
+    G.re.fill(0.f);
+    G.im.fill(0.f);
+  }
   main_filter_.Adapt(render_buffer, G);
   data_dumper_->DumpRaw("aec3_subtractor_G_main", G.re);
   data_dumper_->DumpRaw("aec3_subtractor_G_main", G.im);
diff --git a/modules/audio_processing/aec3/subtractor_output.h b/modules/audio_processing/aec3/subtractor_output.h
index 487eb8d5ad..8655665b35 100644
--- a/modules/audio_processing/aec3/subtractor_output.h
+++ b/modules/audio_processing/aec3/subtractor_output.h
@@ -36,24 +36,6 @@ struct SubtractorOutput {
     E2_main.fill(0.f);
     E2_shadow.fill(0.f);
   }
-
-  void ScaleOutputMainFilter(float factor) {
-    for (auto& s : s_main) {
-      s *= factor;
-    }
-    for (auto& e : e_main) {
-      e *= factor;
-    }
-    for (auto& E2 : E2_main) {
-      E2 *= factor * factor;
-    }
-    for (auto& re : E_main.re) {
-      re *= factor;
-    }
-    for (auto& im : E_main.im) {
-      im *= factor;
-    }
-  }
 };
 
 }  // namespace webrtc