From 9845a67bc56a41b657c5c77b3f294b8b5dcd2a74 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Per=20=C3=85hgren?= <peah@webrtc.org>
Date: Mon, 15 Jan 2018 13:09:02 +0100
Subject: [PATCH] Corrected the handling of saturated echoes inside AEC3
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Bug: webrtc:8747
Change-Id: I644e00c5cc73c8c7b5893725fa15fc018de3cc91
Reviewed-on: https://webrtc-review.googlesource.com/39508
Commit-Queue: Per Åhgren <peah@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21620}
---
 modules/audio_processing/aec3/subtractor.cc | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/modules/audio_processing/aec3/subtractor.cc b/modules/audio_processing/aec3/subtractor.cc
index b19bd64792..6fbef9e222 100644
--- a/modules/audio_processing/aec3/subtractor.cc
+++ b/modules/audio_processing/aec3/subtractor.cc
@@ -26,17 +26,26 @@ void PredictionError(const Aec3Fft& fft,
                      const FftData& S,
                      rtc::ArrayView<const float> y,
                      std::array<float, kBlockSize>* e,
-                     std::array<float, kBlockSize>* s) {
+                     std::array<float, kBlockSize>* s,
+                     bool* saturation) {
   std::array<float, kFftLength> tmp;
   fft.Ifft(S, &tmp);
   constexpr float kScale = 1.0f / kFftLengthBy2;
   std::transform(y.begin(), y.end(), tmp.begin() + kFftLengthBy2, e->begin(),
                  [&](float a, float b) { return a - b * kScale; });
 
+  *saturation = false;
+
   if (s) {
     for (size_t k = 0; k < s->size(); ++k) {
       (*s)[k] = kScale * tmp[k + kFftLengthBy2];
     }
+    auto result = std::minmax_element(s->begin(), s->end());
+    *saturation = *result.first <= -32768 || *result.first >= 32767;
+  }
+  if (!(*saturation)) {
+    auto result = std::minmax_element(e->begin(), e->end());
+    *saturation = *result.first <= -32768 || *result.first >= 32767;
   }
 
   std::for_each(e->begin(), e->end(),
@@ -135,14 +144,16 @@ void Subtractor::Process(const RenderBuffer& render_buffer,
 
   // Form the output of the main filter.
   main_filter_.Filter(render_buffer, &S);
-  PredictionError(fft_, S, y, &e_main, &output->s_main);
+  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);
-  PredictionError(fft_, S, y, &e_shadow, nullptr);
+  bool shadow_saturation = false;
+  PredictionError(fft_, S, y, &e_shadow, nullptr, &shadow_saturation);
   fft_.ZeroPaddedFft(e_shadow, Aec3Fft::Window::kHanning, &E_shadow);
 
   if (!converged_filter_) {
@@ -167,7 +178,7 @@ void Subtractor::Process(const RenderBuffer& render_buffer,
   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(), &G);
+                  aec_state.SaturatedCapture() || main_saturation, &G);
   main_filter_.Adapt(render_buffer, G);
   data_dumper_->DumpRaw("aec3_subtractor_G_main", G.re);
   data_dumper_->DumpRaw("aec3_subtractor_G_main", G.im);
@@ -178,7 +189,7 @@ void Subtractor::Process(const RenderBuffer& render_buffer,
   }
   G_shadow_.Compute(X2, render_signal_analyzer, E_shadow,
                     shadow_filter_.SizePartitions(),
-                    aec_state.SaturatedCapture(), &G);
+                    aec_state.SaturatedCapture() || shadow_saturation, &G);
   shadow_filter_.Adapt(render_buffer, G);
 
   data_dumper_->DumpRaw("aec3_subtractor_G_shadow", G.re);