From c9b89aaa16ef8c2c58ef1a4b21880b92ae7c850a Mon Sep 17 00:00:00 2001
From: Gustaf Ullberg <gustaf@webrtc.org>
Date: Thu, 16 Nov 2017 11:20:59 +0100
Subject: [PATCH] Compute ERLE over all frequency bins in AEC3.
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Bug: webrtc:8533
Change-Id: I0a373f22ec377b226d3bc7d88d3245a99e18c7a0
Reviewed-on: https://webrtc-review.googlesource.com/23621
Reviewed-by: Per Åhgren <peah@webrtc.org>
Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20709}
---
 .../audio_processing/aec3/erle_estimator.cc   | 21 +++++++++++++++++++
 .../audio_processing/aec3/erle_estimator.h    |  3 +++
 .../aec3/erle_estimator_unittest.cc           | 10 +++++----
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/modules/audio_processing/aec3/erle_estimator.cc b/modules/audio_processing/aec3/erle_estimator.cc
index 2b669c93d8..9f7efd4295 100644
--- a/modules/audio_processing/aec3/erle_estimator.cc
+++ b/modules/audio_processing/aec3/erle_estimator.cc
@@ -11,6 +11,7 @@
 #include "modules/audio_processing/aec3/erle_estimator.h"
 
 #include <algorithm>
+#include <numeric>
 
 #include "rtc_base/safe_minmax.h"
 
@@ -24,6 +25,8 @@ ErleEstimator::ErleEstimator(float min_erle,
       max_erle_hf_(max_erle_hf) {
   erle_.fill(min_erle_);
   hold_counters_.fill(0);
+  erle_time_domain_ = min_erle_;
+  hold_counter_time_domain_ = 0;
 }
 
 ErleEstimator::~ErleEstimator() = default;
@@ -64,6 +67,24 @@ void ErleEstimator::Update(
 
   erle_[0] = erle_[1];
   erle_[kFftLengthBy2] = erle_[kFftLengthBy2 - 1];
+
+  // Compute ERLE over all frequency bins.
+  const float X2_sum = std::accumulate(X2.begin(), X2.end(), 0.0f);
+  const float E2_sum = std::accumulate(E2.begin(), E2.end(), 0.0f);
+  if (X2_sum > kX2Min * X2.size() && E2_sum > 0.f) {
+    const float Y2_sum = std::accumulate(Y2.begin(), Y2.end(), 0.0f);
+    const float new_erle = Y2_sum / E2_sum;
+    if (new_erle > erle_time_domain_) {
+      hold_counter_time_domain_ = 100;
+      erle_time_domain_ += 0.1f * (new_erle - erle_time_domain_);
+      erle_time_domain_ =
+          rtc::SafeClamp(erle_time_domain_, min_erle_, max_erle_lf_);
+    }
+  }
+  --hold_counter_time_domain_;
+  erle_time_domain_ = (hold_counter_time_domain_ > 0)
+                        ? erle_time_domain_
+                        : std::max(min_erle_, 0.97f * erle_time_domain_);
 }
 
 }  // namespace webrtc
diff --git a/modules/audio_processing/aec3/erle_estimator.h b/modules/audio_processing/aec3/erle_estimator.h
index 80c0387981..71fdfb50a5 100644
--- a/modules/audio_processing/aec3/erle_estimator.h
+++ b/modules/audio_processing/aec3/erle_estimator.h
@@ -31,10 +31,13 @@ class ErleEstimator {
 
   // Returns the most recent ERLE estimate.
   const std::array<float, kFftLengthBy2Plus1>& Erle() const { return erle_; }
+  float ErleTimeDomain() { return erle_time_domain_; }
 
  private:
   std::array<float, kFftLengthBy2Plus1> erle_;
   std::array<int, kFftLengthBy2Minus1> hold_counters_;
+  float erle_time_domain_;
+  int hold_counter_time_domain_;
   const float min_erle_;
   const float max_erle_lf_;
   const float max_erle_hf_;
diff --git a/modules/audio_processing/aec3/erle_estimator_unittest.cc b/modules/audio_processing/aec3/erle_estimator_unittest.cc
index bc5ac193c5..f3dd7d9bbb 100644
--- a/modules/audio_processing/aec3/erle_estimator_unittest.cc
+++ b/modules/audio_processing/aec3/erle_estimator_unittest.cc
@@ -18,6 +18,7 @@ namespace {
 constexpr int kLowFrequencyLimit = kFftLengthBy2 / 2;
 
 void VerifyErle(const std::array<float, kFftLengthBy2Plus1>& erle,
+                float erle_time_domain,
                 float reference_lf,
                 float reference_hf) {
   std::for_each(
@@ -26,6 +27,7 @@ void VerifyErle(const std::array<float, kFftLengthBy2Plus1>& erle,
   std::for_each(
       erle.begin() + kLowFrequencyLimit, erle.end(),
       [reference_hf](float a) { EXPECT_NEAR(reference_hf, a, 0.001); });
+  EXPECT_NEAR(reference_lf, erle_time_domain, 0.001);
 }
 
 }  // namespace
@@ -45,7 +47,7 @@ TEST(ErleEstimator, Estimates) {
   for (size_t k = 0; k < 200; ++k) {
     estimator.Update(X2, Y2, E2);
   }
-  VerifyErle(estimator.Erle(), 8.f, 1.5f);
+  VerifyErle(estimator.Erle(), estimator.ErleTimeDomain(), 8.f, 1.5f);
 
   // Verifies that the ERLE is not immediately decreased when the ERLE in the
   // data decreases.
@@ -53,13 +55,13 @@ TEST(ErleEstimator, Estimates) {
   for (size_t k = 0; k < 98; ++k) {
     estimator.Update(X2, Y2, E2);
   }
-  VerifyErle(estimator.Erle(), 8.f, 1.5f);
+  VerifyErle(estimator.Erle(), estimator.ErleTimeDomain(), 8.f, 1.5f);
 
   // Verifies that the minimum ERLE is eventually achieved.
   for (size_t k = 0; k < 1000; ++k) {
     estimator.Update(X2, Y2, E2);
   }
-  VerifyErle(estimator.Erle(), 1.f, 1.f);
+  VerifyErle(estimator.Erle(), estimator.ErleTimeDomain(), 1.f, 1.f);
 
   // Verifies that the ERLE estimate is is not updated for low-level render
   // signals.
@@ -68,6 +70,6 @@ TEST(ErleEstimator, Estimates) {
   for (size_t k = 0; k < 200; ++k) {
     estimator.Update(X2, Y2, E2);
   }
-  VerifyErle(estimator.Erle(), 1.f, 1.f);
+  VerifyErle(estimator.Erle(), estimator.ErleTimeDomain(), 1.f, 1.f);
 }
 }  // namespace webrtc