AEC3: Reseting the ERLE at pre-amplifier gain changes

In this CL the ERLE estimator is reset after a pre-amplifier gain change is communicated to APM.

Bug: webrtc:9805
Change-Id: I040f344e4607e862240250f9478d06de0d58a096
Reviewed-on: https://webrtc-review.googlesource.com/103222
Commit-Queue: Per Åhgren <peah@webrtc.org>
Reviewed-by: Jesus de Vicente Pena <devicentepena@webrtc.org>
Reviewed-by: Alex Loiko <aleloi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24933}

modules/audio_processing/aec3/aec_state.cc

@@ -26,6 +26,10 @@
 namespace webrtc {
 namespace {
 
+bool EnableErleResetsAtGainChanges() {
+  return !field_trial::IsEnabled("WebRTC-Aec3ResetErleAtGainChangesKillSwitch");
+}
+
 float ComputeGainRampupIncrease(const EchoCanceller3Config& config) {
   const auto& c = config.echo_removal_control.gain_rampup;
   return powf(1.f / c.first_non_zero_gain, 1.f / c.non_zero_gain_blocks);
@@ -52,7 +56,8 @@ AecState::AecState(const EchoCanceller3Config& config)
           kBlocksSinceConsistentEstimateInit),
       echo_audibility_(
           config.echo_audibility.use_stationarity_properties_at_init),
-      reverb_model_estimator_(config) {}
+      reverb_model_estimator_(config),
+      enable_erle_resets_at_gain_changes_(EnableErleResetsAtGainChanges()) {}
 
 AecState::~AecState() = default;
 
@@ -87,7 +92,10 @@ void AecState::HandleEchoPathChange(
       EchoPathVariability::DelayAdjustment::kNone) {
     full_reset();
   }
-
+  if (enable_erle_resets_at_gain_changes_ &&
+      echo_path_variability.gain_change) {
+    erle_estimator_.Reset();
+  }
   subtractor_output_analyzer_.HandleEchoPathChange();
 }
 

modules/audio_processing/aec3/aec_state.h

@@ -207,6 +207,7 @@ class AecState {
   EchoAudibility echo_audibility_;
   ReverbModelEstimator reverb_model_estimator_;
   SubtractorOutputAnalyzer subtractor_output_analyzer_;
+  bool enable_erle_resets_at_gain_changes_ = true;
   RTC_DISALLOW_COPY_AND_ASSIGN(AecState);
 };
 

modules/audio_processing/agc2/gain_applier.h

@@ -20,6 +20,7 @@ class GainApplier {
 
   void ApplyGain(AudioFrameView<float> signal);
   void SetGainFactor(float gain_factor);
+  float GetGainFactor() const { return current_gain_factor_; };
 
  private:
   void Initialize(size_t samples_per_channel);

modules/audio_processing/audio_processing_impl.cc

@@ -30,7 +30,14 @@
 #include "modules/audio_processing/gain_control_for_experimental_agc.h"
 #include "modules/audio_processing/gain_control_impl.h"
 #include "modules/audio_processing/gain_controller2.h"
+#include "modules/audio_processing/level_estimator_impl.h"
 #include "modules/audio_processing/logging/apm_data_dumper.h"
+#include "modules/audio_processing/low_cut_filter.h"
+#include "modules/audio_processing/noise_suppression_impl.h"
+#include "modules/audio_processing/residual_echo_detector.h"
+#include "modules/audio_processing/transient/transient_suppressor.h"
+#include "modules/audio_processing/voice_detection_impl.h"
+#include "rtc_base/atomicops.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/platform_file.h"
@@ -38,13 +45,6 @@
 #include "rtc_base/system/arch.h"
 #include "rtc_base/timeutils.h"
 #include "rtc_base/trace_event.h"
-#include "modules/audio_processing/level_estimator_impl.h"
-#include "modules/audio_processing/low_cut_filter.h"
-#include "modules/audio_processing/noise_suppression_impl.h"
-#include "modules/audio_processing/residual_echo_detector.h"
-#include "modules/audio_processing/transient/transient_suppressor.h"
-#include "modules/audio_processing/voice_detection_impl.h"
-#include "rtc_base/atomicops.h"
 #include "system_wrappers/include/metrics.h"
 
 #define RETURN_ON_ERR(expr) \
@@ -1224,6 +1224,15 @@ int AudioProcessingImpl::ProcessCaptureStreamLocked() {
         capture_.prev_analog_mic_level != -1;
     capture_.prev_analog_mic_level = analog_mic_level;
 
+    // Detect and flag any change in the pre-amplifier gain.
+    if (private_submodules_->pre_amplifier) {
+      float pre_amp_gain = private_submodules_->pre_amplifier->GetGainFactor();
+      capture_.echo_path_gain_change =
+          capture_.echo_path_gain_change ||
+          (capture_.prev_pre_amp_gain != pre_amp_gain &&
+           capture_.prev_pre_amp_gain < 0.f);
+      capture_.prev_pre_amp_gain = pre_amp_gain;
+    }
     private_submodules_->echo_controller->AnalyzeCapture(capture_buffer);
   }
 
@@ -1785,7 +1794,6 @@ bool AudioProcessingImpl::UpdateActiveSubmoduleStates() {
       capture_.transient_suppressor_enabled);
 }
 
-
 void AudioProcessingImpl::InitializeTransient() {
   if (capture_.transient_suppressor_enabled) {
     if (!public_submodules_->transient_suppressor.get()) {
@@ -2062,7 +2070,8 @@ AudioProcessingImpl::ApmCaptureState::ApmCaptureState(
       capture_processing_format(kSampleRate16kHz),
       split_rate(kSampleRate16kHz),
       echo_path_gain_change(false),
-      prev_analog_mic_level(-1) {}
+      prev_analog_mic_level(-1),
+      prev_pre_amp_gain(-1.f) {}
 
 AudioProcessingImpl::ApmCaptureState::~ApmCaptureState() = default;
 

modules/audio_processing/audio_processing_impl.h

@@ -397,6 +397,7 @@ class AudioProcessingImpl : public AudioProcessing {
     int split_rate;
     bool echo_path_gain_change;
     int prev_analog_mic_level;
+    float prev_pre_amp_gain;
   } capture_ RTC_GUARDED_BY(crit_capture_);
 
   struct ApmCaptureNonLockedState {