From 0f46441772a1e30b4297e7e6b919fdc6f69b1b4f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Per=20=C3=85hgren?= <peah@webrtc.org>
Date: Mon, 9 Oct 2017 12:21:56 +0200
Subject: [PATCH] Added the ability to set the default echo path delay in AEC3.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This CL adds the ability to set a default echo path delay to use
in AEC3 when there is prior knowledge about the delay in the echo
path.


Bug: webrtc:8358
Change-Id: Ie368f9a6dec9f412e09bf0e095f89d84305045f9
Reviewed-on: https://webrtc-review.googlesource.com/7604
Commit-Queue: Per Åhgren <peah@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20204}
---
 .../audio_processing/aec3/render_delay_controller.cc  | 11 ++++++++---
 modules/audio_processing/include/audio_processing.h   |  4 ++++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/modules/audio_processing/aec3/render_delay_controller.cc b/modules/audio_processing/aec3/render_delay_controller.cc
index 9b400ff111..1a30cdff6d 100644
--- a/modules/audio_processing/aec3/render_delay_controller.cc
+++ b/modules/audio_processing/aec3/render_delay_controller.cc
@@ -42,10 +42,11 @@ class RenderDelayControllerImpl final : public RenderDelayController {
  private:
   static int instance_count_;
   std::unique_ptr<ApmDataDumper> data_dumper_;
-  size_t delay_ = kMinEchoPathDelayBlocks;
+  const size_t default_delay_;
+  size_t delay_;
   EchoPathDelayEstimator delay_estimator_;
   size_t blocks_since_last_delay_estimate_ = 300000;
-  int echo_path_delay_samples_ = kMinEchoPathDelayBlocks * kBlockSize;
+  int echo_path_delay_samples_;
   size_t align_call_counter_ = 0;
   rtc::Optional<size_t> headroom_samples_;
   std::vector<float> capture_delay_buffer_;
@@ -78,7 +79,11 @@ RenderDelayControllerImpl::RenderDelayControllerImpl(
     int sample_rate_hz)
     : data_dumper_(
           new ApmDataDumper(rtc::AtomicOps::Increment(&instance_count_))),
+      default_delay_(
+          std::max(config.param.delay.default_delay, kMinEchoPathDelayBlocks)),
+      delay_(default_delay_),
       delay_estimator_(data_dumper_.get(), config),
+      echo_path_delay_samples_(default_delay_ * kBlockSize),
       capture_delay_buffer_(kBlockSize * (kMaxApiCallsJitterBlocks + 2), 0.f) {
   RTC_DCHECK(ValidFullBandRate(sample_rate_hz));
 }
@@ -86,7 +91,7 @@ RenderDelayControllerImpl::RenderDelayControllerImpl(
 RenderDelayControllerImpl::~RenderDelayControllerImpl() = default;
 
 void RenderDelayControllerImpl::Reset() {
-  delay_ = kMinEchoPathDelayBlocks;
+  delay_ = default_delay_;
   blocks_since_last_delay_estimate_ = 300000;
   echo_path_delay_samples_ = delay_ * kBlockSize;
   align_call_counter_ = 0;
diff --git a/modules/audio_processing/include/audio_processing.h b/modules/audio_processing/include/audio_processing.h
index 6aeefd648b..665760c0e2 100644
--- a/modules/audio_processing/include/audio_processing.h
+++ b/modules/audio_processing/include/audio_processing.h
@@ -272,6 +272,10 @@ class AudioProcessing : public rtc::RefCountInterface {
     // does not yet have the desired behavior.
     struct EchoCanceller3 {
       struct Param {
+        struct Delay {
+          size_t default_delay = 5;
+        } delay;
+
         struct Erle {
           float min = 1.f;
           float max_l = 8.f;