From 6799553a2cbe2470115a7db01ed14f4a4c593d88 Mon Sep 17 00:00:00 2001
From: peah <peah@webrtc.org>
Date: Mon, 10 Apr 2017 14:12:41 -0700
Subject: [PATCH] Add information about microphone gain changes to AEC3

Changes in the microphone gain are effecting the AEC in the sense
that each change in the microphone gain is a change in the echo
path seen by the AEC. This CL utilizes the ability of AEC3 to
leverage information about known changes in the analog microphone
gain.

BUG=webrtc:6018

Review-Url: https://codereview.webrtc.org/2808073002
Cr-Commit-Position: refs/heads/master@{#17625}
---
 .../modules/audio_processing/audio_processing_impl.cc | 11 +++++++++--
 .../modules/audio_processing/audio_processing_impl.h  |  2 ++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/webrtc/modules/audio_processing/audio_processing_impl.cc b/webrtc/modules/audio_processing/audio_processing_impl.cc
index 636d6ca5f0..af5e94b602 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl.cc
+++ b/webrtc/modules/audio_processing/audio_processing_impl.cc
@@ -1145,6 +1145,10 @@ int AudioProcessingImpl::ProcessCaptureStreamLocked() {
   }
 
   if (private_submodules_->echo_canceller3) {
+    const int new_agc_level = gain_control()->stream_analog_level();
+    capture_.echo_path_gain_change =
+        (capture_.previous_agc_level != new_agc_level);
+    capture_.previous_agc_level = new_agc_level;
     private_submodules_->echo_canceller3->AnalyzeCapture(capture_buffer);
   }
 
@@ -1193,7 +1197,8 @@ int AudioProcessingImpl::ProcessCaptureStreamLocked() {
   }
 
   if (private_submodules_->echo_canceller3) {
-    private_submodules_->echo_canceller3->ProcessCapture(capture_buffer, false);
+    private_submodules_->echo_canceller3->ProcessCapture(
+        capture_buffer, capture_.echo_path_gain_change);
   } else {
     RETURN_ON_ERR(public_submodules_->echo_cancellation->ProcessCaptureAudio(
         capture_buffer, stream_delay_ms()));
@@ -1993,7 +1998,9 @@ AudioProcessingImpl::ApmCaptureState::ApmCaptureState(
       array_geometry(array_geometry),
       target_direction(target_direction),
       capture_processing_format(kSampleRate16kHz),
-      split_rate(kSampleRate16kHz) {}
+      split_rate(kSampleRate16kHz),
+      previous_agc_level(0),
+      echo_path_gain_change(false) {}
 
 AudioProcessingImpl::ApmCaptureState::~ApmCaptureState() = default;
 
diff --git a/webrtc/modules/audio_processing/audio_processing_impl.h b/webrtc/modules/audio_processing/audio_processing_impl.h
index 4e25f15e36..37b15c2893 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl.h
+++ b/webrtc/modules/audio_processing/audio_processing_impl.h
@@ -366,6 +366,8 @@ class AudioProcessingImpl : public AudioProcessing {
     // tracked by the capture_audio_.
     StreamConfig capture_processing_format;
     int split_rate;
+    int previous_agc_level;
+    bool echo_path_gain_change;
   } capture_ GUARDED_BY(crit_capture_);
 
   struct ApmCaptureNonLockedState {