From 15179a998631f5e45da13d600fd067da18bd71ff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Per=20=C3=85hgren?= <peah@webrtc.org>
Date: Fri, 12 Mar 2021 14:12:44 +0000
Subject: [PATCH] Allowing reduced computations in the noise suppressor when
 the output is not used
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This CL adds functionality in the noise suppressor that allows the
computational complexity to be reduced when the output of APM is not used.

Bug: b/177830919
Change-Id: I849351ba9559fae770e4667d78e38abde5230eed
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/211342
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33477}
---
 modules/audio_processing/audio_processing_impl.cc | 4 ++++
 modules/audio_processing/ns/noise_suppressor.cc   | 6 ++++++
 modules/audio_processing/ns/noise_suppressor.h    | 9 +++++++++
 3 files changed, 19 insertions(+)

diff --git a/modules/audio_processing/audio_processing_impl.cc b/modules/audio_processing/audio_processing_impl.cc
index 496f985e42..b23d363dc3 100644
--- a/modules/audio_processing/audio_processing_impl.cc
+++ b/modules/audio_processing/audio_processing_impl.cc
@@ -679,6 +679,10 @@ void AudioProcessingImpl::HandleCaptureOutputUsedSetting(
     submodules_.echo_controller->SetCaptureOutputUsage(
         capture_.capture_output_used);
   }
+  if (submodules_.noise_suppressor) {
+    submodules_.noise_suppressor->SetCaptureOutputUsage(
+        capture_.capture_output_used);
+  }
 }
 
 void AudioProcessingImpl::SetRuntimeSetting(RuntimeSetting setting) {
diff --git a/modules/audio_processing/ns/noise_suppressor.cc b/modules/audio_processing/ns/noise_suppressor.cc
index 89e1fe0d91..d66faa6ed4 100644
--- a/modules/audio_processing/ns/noise_suppressor.cc
+++ b/modules/audio_processing/ns/noise_suppressor.cc
@@ -448,6 +448,12 @@ void NoiseSuppressor::Process(AudioBuffer* audio) {
     }
   }
 
+  // Only do the below processing if the output of the audio processing module
+  // is used.
+  if (!capture_output_used_) {
+    return;
+  }
+
   // Aggregate the Wiener filters for all channels.
   std::array<float, kFftSizeBy2Plus1> filter_data;
   rtc::ArrayView<const float, kFftSizeBy2Plus1> filter = filter_data;
diff --git a/modules/audio_processing/ns/noise_suppressor.h b/modules/audio_processing/ns/noise_suppressor.h
index d9628869bb..1e321cf4a2 100644
--- a/modules/audio_processing/ns/noise_suppressor.h
+++ b/modules/audio_processing/ns/noise_suppressor.h
@@ -41,12 +41,21 @@ class NoiseSuppressor {
   // Applies noise suppression.
   void Process(AudioBuffer* audio);
 
+  // Specifies whether the capture output will be used. The purpose of this is
+  // to allow the noise suppressor to deactivate some of the processing when the
+  // resulting output is anyway not used, for instance when the endpoint is
+  // muted.
+  void SetCaptureOutputUsage(bool capture_output_used) {
+    capture_output_used_ = capture_output_used;
+  }
+
  private:
   const size_t num_bands_;
   const size_t num_channels_;
   const SuppressionParams suppression_params_;
   int32_t num_analyzed_frames_ = -1;
   NrFft fft_;
+  bool capture_output_used_ = true;
 
   struct ChannelState {
     ChannelState(const SuppressionParams& suppression_params, size_t num_bands);