From b5adc9e4cb999902a5b3677fea3db66897effcc1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Per=20=C3=85hgren?= <peah@webrtc.org>
Date: Mon, 15 Jan 2018 13:20:20 +0100
Subject: [PATCH] Use the best of the shadow and main filter characteristics in
 AEC3
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Bug: webrtc:8746
Change-Id: If40a3ac936dcc4f55ce0943c5228a9891160e752
Reviewed-on: https://webrtc-review.googlesource.com/39509
Commit-Queue: Per Åhgren <peah@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21621}
---
 modules/audio_processing/aec3/subtractor.cc | 37 +++++++++++++--------
 modules/audio_processing/aec3/subtractor.h  | 15 ++++++---
 2 files changed, 35 insertions(+), 17 deletions(-)

diff --git a/modules/audio_processing/aec3/subtractor.cc b/modules/audio_processing/aec3/subtractor.cc
index 6fbef9e222..e3b4f87c0f 100644
--- a/modules/audio_processing/aec3/subtractor.cc
+++ b/modules/audio_processing/aec3/subtractor.cc
@@ -97,11 +97,11 @@ void Subtractor::HandleEchoPathChange(
     G_shadow_.HandleEchoPathChange();
     G_main_.SetConfig(config_.filter.main_initial);
     G_shadow_.SetConfig(config_.filter.shadow_initial);
+    main_filter_converged_ = false;
+    shadow_filter_converged_ = false;
     main_filter_.SetSizePartitions(config_.filter.main_initial.length_blocks);
     shadow_filter_.SetSizePartitions(
         config_.filter.shadow_initial.length_blocks);
-
-    converged_filter_ = false;
   };
 
   // TODO(peah): Add delay-change specific reset behavior.
@@ -147,8 +147,6 @@ void Subtractor::Process(const RenderBuffer& render_buffer,
   bool main_saturation = false;
   PredictionError(fft_, S, y, &e_main, &output->s_main, &main_saturation);
   fft_.ZeroPaddedFft(e_main, Aec3Fft::Window::kHanning, &E_main);
-  fft_.ZeroPaddedFft(e_main, Aec3Fft::Window::kRectangular,
-                     &E_main_nonwindowed);
 
   // Form the output of the shadow filter.
   shadow_filter_.Filter(render_buffer, &S);
@@ -156,23 +154,36 @@ void Subtractor::Process(const RenderBuffer& render_buffer,
   PredictionError(fft_, S, y, &e_shadow, nullptr, &shadow_saturation);
   fft_.ZeroPaddedFft(e_shadow, Aec3Fft::Window::kHanning, &E_shadow);
 
-  if (!converged_filter_) {
+  if (!(main_filter_converged_ || shadow_filter_converged_)) {
     const auto sum_of_squares = [](float a, float b) { return a + b * b; };
-    const float e2_main =
-        std::accumulate(e_main.begin(), e_main.end(), 0.f, sum_of_squares);
-    const float e2_shadow =
-        std::accumulate(e_shadow.begin(), e_shadow.end(), 0.f, sum_of_squares);
     const float y2 = std::accumulate(y.begin(), y.end(), 0.f, sum_of_squares);
 
-    if (y2 > kBlockSize * 50.f * 50.f) {
-      converged_filter_ = (e2_main > 0.3 * y2 || e2_shadow > 0.1 * y2);
+    if (!main_filter_converged_) {
+      const float e2_main =
+          std::accumulate(e_main.begin(), e_main.end(), 0.f, sum_of_squares);
+      main_filter_converged_ = e2_main > 0.1 * y2;
+    }
+
+    if (!shadow_filter_converged_) {
+      const float e2_shadow = std::accumulate(e_shadow.begin(), e_shadow.end(),
+                                              0.f, sum_of_squares);
+      shadow_filter_converged_ = e2_shadow > 0.1 * y2;
     }
   }
 
   // Compute spectra for future use.
-  E_main.Spectrum(optimization_, output->E2_main);
-  E_main_nonwindowed.Spectrum(optimization_, output->E2_main_nonwindowed);
   E_shadow.Spectrum(optimization_, output->E2_shadow);
+  E_main.Spectrum(optimization_, output->E2_main);
+
+  if (main_filter_converged_ || !shadow_filter_converged_) {
+    fft_.ZeroPaddedFft(e_main, Aec3Fft::Window::kRectangular,
+                       &E_main_nonwindowed);
+    E_main_nonwindowed.Spectrum(optimization_, output->E2_main_nonwindowed);
+  } else {
+    fft_.ZeroPaddedFft(e_shadow, Aec3Fft::Window::kRectangular,
+                       &E_main_nonwindowed);
+    E_main_nonwindowed.Spectrum(optimization_, output->E2_main_nonwindowed);
+  }
 
   // Update the main filter.
   std::array<float, kFftLengthBy2Plus1> X2;
diff --git a/modules/audio_processing/aec3/subtractor.h b/modules/audio_processing/aec3/subtractor.h
index b267abf721..b3c8506c81 100644
--- a/modules/audio_processing/aec3/subtractor.h
+++ b/modules/audio_processing/aec3/subtractor.h
@@ -53,15 +53,21 @@ class Subtractor {
   // Returns the block-wise frequency response for the main adaptive filter.
   const std::vector<std::array<float, kFftLengthBy2Plus1>>&
   FilterFrequencyResponse() const {
-    return main_filter_.FilterFrequencyResponse();
+    return main_filter_converged_ || (!shadow_filter_converged_)
+               ? main_filter_.FilterFrequencyResponse()
+               : shadow_filter_.FilterFrequencyResponse();
   }
 
   // Returns the estimate of the impulse response for the main adaptive filter.
   const std::vector<float>& FilterImpulseResponse() const {
-    return main_filter_.FilterImpulseResponse();
+    return main_filter_converged_ || (!shadow_filter_converged_)
+               ? main_filter_.FilterImpulseResponse()
+               : shadow_filter_.FilterImpulseResponse();
   }
 
-  bool ConvergedFilter() const { return converged_filter_; }
+  bool ConvergedFilter() const {
+    return main_filter_converged_ || shadow_filter_converged_;
+  }
 
  private:
   const Aec3Fft fft_;
@@ -72,7 +78,8 @@ class Subtractor {
   AdaptiveFirFilter shadow_filter_;
   MainFilterUpdateGain G_main_;
   ShadowFilterUpdateGain G_shadow_;
-  bool converged_filter_ = false;
+  bool main_filter_converged_ = false;
+  bool shadow_filter_converged_ = false;
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(Subtractor);
 };