APM: add field trial to disable TransientSuppressor

Regardless of the APM config, the transient suppressor (TS) submodule
won't be created if the `WebRTC-ApmTransientSuppressorKillSwitch`
field trial, disabled by default, is enabled.

Bug: webrtc:13663
Change-Id: Ic1ef9aa57c728296d671d4ef253630c581a86610
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/286382
Reviewed-by: Hanna Silen <silen@webrtc.org>
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38839}

modules/audio_processing/audio_processing_impl.cc

@@ -394,50 +394,64 @@ GetInputVolumeControllerConfigOverride() {
   };
 }
 
-// Switches all gain control to AGC2 if experimenting with input volume
+// If `disallow_transient_supporessor_usage` is true, disables transient
-// controller.
+// suppression. When `input_volume_controller_config_override` is specified,
-const AudioProcessing::Config AdjustConfig(
+// switches all gain control to AGC2.
+AudioProcessing::Config AdjustConfig(
     const AudioProcessing::Config& config,
+    bool disallow_transient_supporessor_usage,
     const absl::optional<InputVolumeController::Config>&
         input_volume_controller_config_override) {
-  const bool analog_agc_enabled =
+  AudioProcessing::Config adjusted_config = config;
+
+  // Override the transient suppressor configuration.
+  if (disallow_transient_supporessor_usage) {
+    adjusted_config.transient_suppression.enabled = false;
+  }
+
+  // Override the auto gain control configuration if the AGC1 analog gain
+  // controller is active and `input_volume_controller_config_override` is
+  // specified.
+  const bool agc1_analog_enabled =
       config.gain_controller1.enabled &&
       (config.gain_controller1.mode ==
            AudioProcessing::Config::GainController1::kAdaptiveAnalog ||
        config.gain_controller1.analog_gain_controller.enabled);
-
+  if (agc1_analog_enabled &&
-  // Do not update the config if none of the analog AGCs is active
+      input_volume_controller_config_override.has_value()) {
-  // regardless of the input volume controller override.
+    // Check that the unadjusted AGC config meets the preconditions.
-  if (!analog_agc_enabled ||
-      !input_volume_controller_config_override.has_value()) {
-    return config;
-  }
-
     const bool hybrid_agc_config_detected =
         config.gain_controller1.enabled &&
         config.gain_controller1.analog_gain_controller.enabled &&
-      !config.gain_controller1.analog_gain_controller.enable_digital_adaptive &&
+        !config.gain_controller1.analog_gain_controller
+             .enable_digital_adaptive &&
         config.gain_controller2.enabled &&
         config.gain_controller2.adaptive_digital.enabled;
-
     const bool full_agc1_config_detected =
         config.gain_controller1.enabled &&
         config.gain_controller1.analog_gain_controller.enabled &&
-      config.gain_controller1.analog_gain_controller.enable_digital_adaptive &&
+        config.gain_controller1.analog_gain_controller
+            .enable_digital_adaptive &&
         !config.gain_controller2.enabled;
-
+    const bool one_and_only_one_input_volume_controller =
-  if (hybrid_agc_config_detected == full_agc1_config_detected ||
+        hybrid_agc_config_detected != full_agc1_config_detected;
+    if (!one_and_only_one_input_volume_controller ||
         config.gain_controller2.input_volume_controller.enabled) {
-    RTC_LOG(LS_ERROR) << "Unexpected AGC config: Config not adjusted.";
+      RTC_LOG(LS_ERROR) << "Cannot adjust AGC config (precondition failed)";
-    return config;
+      if (!one_and_only_one_input_volume_controller)
-  }
+        RTC_LOG(LS_ERROR)
-
+            << "One and only one input volume controller must be enabled.";
-  AudioProcessing::Config adjusted_config = config;
+      if (config.gain_controller2.input_volume_controller.enabled)
+        RTC_LOG(LS_ERROR)
+            << "The AGC2 input volume controller must be disabled.";
+    } else {
       adjusted_config.gain_controller1.enabled = false;
       adjusted_config.gain_controller1.analog_gain_controller.enabled = false;
       adjusted_config.gain_controller2.enabled = true;
       adjusted_config.gain_controller2.adaptive_digital.enabled = true;
       adjusted_config.gain_controller2.input_volume_controller.enabled = true;
+    }
+  }
 
   return adjusted_config;
 }
@@ -583,13 +597,17 @@ AudioProcessingImpl::AudioProcessingImpl(
           GetInputVolumeControllerConfigOverride()),
       use_denormal_disabler_(
           !field_trial::IsEnabled("WebRTC-ApmDenormalDisablerKillSwitch")),
+      disallow_transient_supporessor_usage_(
+          field_trial::IsEnabled("WebRTC-ApmTransientSuppressorKillSwitch")),
       transient_suppressor_vad_mode_(GetTransientSuppressorVadMode()),
       capture_runtime_settings_(RuntimeSettingQueueSize()),
       render_runtime_settings_(RuntimeSettingQueueSize()),
       capture_runtime_settings_enqueuer_(&capture_runtime_settings_),
       render_runtime_settings_enqueuer_(&render_runtime_settings_),
       echo_control_factory_(std::move(echo_control_factory)),
-      config_(AdjustConfig(config, input_volume_controller_config_override_)),
+      config_(AdjustConfig(config,
+                           disallow_transient_supporessor_usage_,
+                           input_volume_controller_config_override_)),
       submodule_states_(!!capture_post_processor,
                         !!render_pre_processor,
                         !!capture_analyzer),
@@ -824,11 +842,9 @@ void AudioProcessingImpl::ApplyConfig(const AudioProcessing::Config& config) {
   MutexLock lock_render(&mutex_render_);
   MutexLock lock_capture(&mutex_capture_);
 
-  // TODO(bugs.webrtc.org/7494): Replace `adjusted_config` with `config` after
-  // "WebRTC-Audio-InputVolumeControllerExperiment" field trial is removed.
   const auto adjusted_config =
-      AdjustConfig(config, input_volume_controller_config_override_);
+      AdjustConfig(config, disallow_transient_supporessor_usage_,
-
+                   input_volume_controller_config_override_);
   RTC_LOG(LS_INFO) << "AudioProcessing::ApplyConfig: "
                    << adjusted_config.ToString();
 

modules/audio_processing/audio_processing_impl.h

@@ -191,14 +191,19 @@ class AudioProcessingImpl : public AudioProcessing {
   static std::atomic<int> instance_count_;
   const bool use_setup_specific_default_aec3_config_;
 
-  // TODO(bugs.webrtc.org/7494): Remove the the config when the field trial is
+  // TODO(bugs.webrtc.org/7494): Remove when the linked field trial is removed.
-  // removed. "WebRTC-Audio-InputVolumeControllerExperiment" field trial
+  // Override base on the "WebRTC-Audio-InputVolumeControllerExperiment" field
-  // override for the input volume controller config.
+  // trial for the AGC2 input volume controller configuration.
   const absl::optional<InputVolumeController::Config>
       input_volume_controller_config_override_;
 
   const bool use_denormal_disabler_;
 
+  // When true, the transient suppressor submodule is never created regardless
+  // of the APM configuration.
+  // TODO(bugs.webrtc.org/13663): Remove when the linked field trial is removed.
+  const bool disallow_transient_supporessor_usage_;
+
   const TransientSuppressor::VadMode transient_suppressor_vad_mode_;
 
   SwapQueue<RuntimeSetting> capture_runtime_settings_;

modules/audio_processing/audio_processing_impl_unittest.cc

@@ -960,6 +960,55 @@ TEST(ApmWithSubmodulesExcludedTest, ToggleTransientSuppressor) {
   }
 }
 
+TEST(AudioProcessingImplTest, CanDisableTransientSuppressor) {
+  // Do not explicitly disable "WebRTC-ApmTransientSuppressorKillSwitch" since
+  // to check that, by default, it is disabled.
+  auto apm = AudioProcessingBuilder()
+                 .SetConfig({.transient_suppression = {.enabled = false}})
+                 .Create();
+  EXPECT_FALSE(apm->GetConfig().transient_suppression.enabled);
+}
+
+TEST(AudioProcessingImplTest, CanEnableTransientSuppressor) {
+  // Do not explicitly disable "WebRTC-ApmTransientSuppressorKillSwitch" since
+  // to check that, by default, it is disabled.
+  auto apm = AudioProcessingBuilder()
+                 .SetConfig({.transient_suppression = {.enabled = true}})
+                 .Create();
+  EXPECT_TRUE(apm->GetConfig().transient_suppression.enabled);
+}
+
+TEST(AudioProcessingImplTest, CanDisableTransientSuppressorIfUsageAllowed) {
+  // Disable the field trial that disallows to enable transient suppression.
+  test::ScopedFieldTrials field_trials(
+      "WebRTC-ApmTransientSuppressorKillSwitch/Disabled/");
+  auto apm = AudioProcessingBuilder()
+                 .SetConfig({.transient_suppression = {.enabled = false}})
+                 .Create();
+  EXPECT_FALSE(apm->GetConfig().transient_suppression.enabled);
+}
+
+TEST(AudioProcessingImplTest, CanEnableTransientSuppressorIfUsageAllowed) {
+  // Disable the field trial that disallows to enable transient suppression.
+  test::ScopedFieldTrials field_trials(
+      "WebRTC-ApmTransientSuppressorKillSwitch/Disabled/");
+  auto apm = AudioProcessingBuilder()
+                 .SetConfig({.transient_suppression = {.enabled = true}})
+                 .Create();
+  EXPECT_TRUE(apm->GetConfig().transient_suppression.enabled);
+}
+
+TEST(AudioProcessingImplTest,
+     CannotEnableTransientSuppressorIfUsageDisallowed) {
+  // Enable the field trial that disallows to enable transient suppression.
+  test::ScopedFieldTrials field_trials(
+      "WebRTC-ApmTransientSuppressorKillSwitch/Enabled/");
+  auto apm = AudioProcessingBuilder()
+                 .SetConfig({.transient_suppression = {.enabled = true}})
+                 .Create();
+  EXPECT_FALSE(apm->GetConfig().transient_suppression.enabled);
+}
+
 // Tests that the minimum startup volume is applied at the startup.
 TEST_P(InputVolumeStartupParameterizedTest,
        VerifyStartupMinVolumeAppliedAtStartup) {