From fddaf7528a34e397411a15dd92161339955ff456 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Per=20=C3=85hgren?= <peah@webrtc.org>
Date: Fri, 8 Jun 2018 10:26:40 +0200
Subject: [PATCH] AEC3: Increase the look window in the delay estimator.
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Bug: webrtc:9374,chromium:850525
Change-Id: I587cb7951acf8e5ec92d9941f1979ba2c9887876
Reviewed-on: https://webrtc-review.googlesource.com/81747
Commit-Queue: Per Åhgren <peah@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23561}
---
 api/audio/echo_canceller3_config.h               |  2 +-
 modules/audio_processing/aec3/echo_canceller3.cc | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/api/audio/echo_canceller3_config.h b/api/audio/echo_canceller3_config.h
index e5bda8617d..a58362ebec 100644
--- a/api/audio/echo_canceller3_config.h
+++ b/api/audio/echo_canceller3_config.h
@@ -22,7 +22,7 @@ struct EchoCanceller3Config {
   struct Delay {
     size_t default_delay = 5;
     size_t down_sampling_factor = 4;
-    size_t num_filters = 5;
+    size_t num_filters = 6;
     size_t api_call_jitter_blocks = 26;
     size_t min_echo_path_delay_blocks = 0;
     size_t delay_headroom_blocks = 2;
diff --git a/modules/audio_processing/aec3/echo_canceller3.cc b/modules/audio_processing/aec3/echo_canceller3.cc
index 765e4de073..07ee54f1b5 100644
--- a/modules/audio_processing/aec3/echo_canceller3.cc
+++ b/modules/audio_processing/aec3/echo_canceller3.cc
@@ -12,6 +12,7 @@
 #include "modules/audio_processing/logging/apm_data_dumper.h"
 #include "rtc_base/atomicops.h"
 #include "rtc_base/logging.h"
+#include "system_wrappers/include/field_trial.h"
 
 namespace webrtc {
 
@@ -28,6 +29,10 @@ bool DetectSaturation(rtc::ArrayView<const float> y) {
   return false;
 }
 
+bool UseShortDelayEstimatorWindow() {
+  return field_trial::IsEnabled("WebRTC-Aec3UseShortDelayEstimatorWindow");
+}
+
 // Method for adjusting config parameter dependencies..
 EchoCanceller3Config AdjustConfig(const EchoCanceller3Config& config) {
   EchoCanceller3Config adjusted_cfg = config;
@@ -62,6 +67,12 @@ EchoCanceller3Config AdjustConfig(const EchoCanceller3Config& config) {
       adjusted_cfg.echo_model.nonlinear_release = 0.6f;
     }
   }
+
+  if (UseShortDelayEstimatorWindow()) {
+    adjusted_cfg.delay.num_filters =
+        std::min(adjusted_cfg.delay.num_filters, static_cast<size_t>(5));
+  }
+
   return adjusted_cfg;
 }