Add support for toggling builtin voice processing on iOS

Bug: None
Change-Id: I3b64afdaed4777960124f248840f36598bba2ed4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/195443
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Commit-Queue: Sam Zackrisson <saza@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32742}

modules/audio_device/audio_device_impl.cc

@@ -280,7 +280,8 @@ int32_t AudioDeviceModuleImpl::CreatePlatformSpecificObjects() {
 // iOS ADM implementation.
 #if defined(WEBRTC_IOS)
   if (audio_layer == kPlatformDefaultAudio) {
-    audio_device_.reset(new ios_adm::AudioDeviceIOS());
+    audio_device_.reset(
+        new ios_adm::AudioDeviceIOS(/*bypass_voice_processing=*/false));
     RTC_LOG(INFO) << "iPhone Audio APIs will be utilized.";
   }
 // END #if defined(WEBRTC_IOS)

sdk/objc/native/api/audio_device_module.h

@@ -17,7 +17,13 @@
 
 namespace webrtc {
 
-rtc::scoped_refptr<AudioDeviceModule> CreateAudioDeviceModule();
+// If |bypass_voice_processing| is true, WebRTC will attempt to disable hardware
+// audio processing on iOS.
+// Warning: Setting |bypass_voice_processing| will have unpredictable
+// consequences for the audio path in the device. It is not advisable to use in
+// most scenarios.
+rtc::scoped_refptr<AudioDeviceModule> CreateAudioDeviceModule(
+    bool bypass_voice_processing = false);
 
 }  // namespace webrtc
 

sdk/objc/native/api/audio_device_module.mm

@@ -17,10 +17,10 @@
 
 namespace webrtc {
 
-rtc::scoped_refptr<AudioDeviceModule> CreateAudioDeviceModule() {
+rtc::scoped_refptr<AudioDeviceModule> CreateAudioDeviceModule(bool bypass_voice_processing) {
   RTC_LOG(INFO) << __FUNCTION__;
 #if defined(WEBRTC_IOS)
-  return new rtc::RefCountedObject<ios_adm::AudioDeviceModuleIOS>();
+  return new rtc::RefCountedObject<ios_adm::AudioDeviceModuleIOS>(bypass_voice_processing);
 #else
   RTC_LOG(LERROR)
       << "current platform is not supported => this module will self destruct!";

sdk/objc/native/src/audio/audio_device_ios.h

@@ -48,7 +48,7 @@ class AudioDeviceIOS : public AudioDeviceGeneric,
                        public VoiceProcessingAudioUnitObserver,
                        public rtc::MessageHandler {
  public:
-  AudioDeviceIOS();
+  explicit AudioDeviceIOS(bool bypass_voice_processing);
   ~AudioDeviceIOS() override;
 
   void AttachAudioBuffer(AudioDeviceBuffer* audioBuffer) override;
@@ -205,6 +205,9 @@ class AudioDeviceIOS : public AudioDeviceGeneric,
   // Resets thread-checkers before a call is restarted.
   void PrepareForNewStart();
 
+  // Determines whether voice processing should be enabled or disabled.
+  const bool bypass_voice_processing_;
+
   // Ensures that methods are called from the same thread as this object is
   // created on.
   rtc::ThreadChecker thread_checker_;

sdk/objc/native/src/audio/audio_device_ios.mm

@@ -100,8 +100,9 @@ static void LogDeviceInfo() {
 }
 #endif  // !defined(NDEBUG)
 
-AudioDeviceIOS::AudioDeviceIOS()
+AudioDeviceIOS::AudioDeviceIOS(bool bypass_voice_processing)
-    : audio_device_buffer_(nullptr),
+    : bypass_voice_processing_(bypass_voice_processing),
+      audio_device_buffer_(nullptr),
       audio_unit_(nullptr),
       recording_(0),
       playing_(0),
@@ -113,7 +114,8 @@ AudioDeviceIOS::AudioDeviceIOS()
       last_playout_time_(0),
       num_playout_callbacks_(0),
       last_output_volume_change_time_(0) {
-  LOGI() << "ctor" << ios::GetCurrentThreadDescription();
+  LOGI() << "ctor" << ios::GetCurrentThreadDescription()
+         << ",bypass_voice_processing=" << bypass_voice_processing_;
   io_thread_checker_.Detach();
   thread_checker_.Detach();
   thread_ = rtc::Thread::Current();
@@ -731,7 +733,7 @@ void AudioDeviceIOS::SetupAudioBuffersForActiveAudioSession() {
 bool AudioDeviceIOS::CreateAudioUnit() {
   RTC_DCHECK(!audio_unit_);
 
-  audio_unit_.reset(new VoiceProcessingAudioUnit(this));
+  audio_unit_.reset(new VoiceProcessingAudioUnit(bypass_voice_processing_, this));
   if (!audio_unit_->Init()) {
     audio_unit_.reset();
     return false;

sdk/objc/native/src/audio/audio_device_module_ios.h

@@ -30,7 +30,7 @@ class AudioDeviceModuleIOS : public AudioDeviceModule {
  public:
   int32_t AttachAudioBuffer();
 
-  AudioDeviceModuleIOS();
+  explicit AudioDeviceModuleIOS(bool bypass_voice_processing);
   ~AudioDeviceModuleIOS() override;
 
   // Retrieve the currently utilized audio layer
@@ -131,6 +131,7 @@ class AudioDeviceModuleIOS : public AudioDeviceModule {
   int GetRecordAudioParameters(AudioParameters* params) const override;
 #endif  // WEBRTC_IOS
  private:
+  const bool bypass_voice_processing_;
   bool initialized_ = false;
   const std::unique_ptr<TaskQueueFactory> task_queue_factory_;
   std::unique_ptr<AudioDeviceIOS> audio_device_;

sdk/objc/native/src/audio/audio_device_module_ios.mm

@@ -40,8 +40,9 @@
 namespace webrtc {
 namespace ios_adm {
 
-AudioDeviceModuleIOS::AudioDeviceModuleIOS()
+AudioDeviceModuleIOS::AudioDeviceModuleIOS(bool bypass_voice_processing)
-    : task_queue_factory_(CreateDefaultTaskQueueFactory()) {
+    : bypass_voice_processing_(bypass_voice_processing),
+      task_queue_factory_(CreateDefaultTaskQueueFactory()) {
   RTC_LOG(INFO) << "current platform is IOS";
   RTC_LOG(INFO) << "iPhone Audio APIs will be utilized.";
 }
@@ -72,7 +73,7 @@ AudioDeviceModuleIOS::AudioDeviceModuleIOS()
       return 0;
 
     audio_device_buffer_.reset(new webrtc::AudioDeviceBuffer(task_queue_factory_.get()));
-    audio_device_.reset(new ios_adm::AudioDeviceIOS());
+    audio_device_.reset(new ios_adm::AudioDeviceIOS(bypass_voice_processing_));
     RTC_CHECK(audio_device_);
 
     this->AttachAudioBuffer();

sdk/objc/native/src/audio/voice_processing_audio_unit.h

@@ -46,7 +46,8 @@ class VoiceProcessingAudioUnitObserver {
 // VoIP applications.
 class VoiceProcessingAudioUnit {
  public:
-  explicit VoiceProcessingAudioUnit(VoiceProcessingAudioUnitObserver* observer);
+  VoiceProcessingAudioUnit(bool bypass_voice_processing,
+                           VoiceProcessingAudioUnitObserver* observer);
   ~VoiceProcessingAudioUnit();
 
   // TODO(tkchin): enum for state and state checking.
@@ -129,6 +130,7 @@ class VoiceProcessingAudioUnit {
   // Deletes the underlying audio unit.
   void DisposeAudioUnit();
 
+  const bool bypass_voice_processing_;
   VoiceProcessingAudioUnitObserver* observer_;
   AudioUnit vpio_unit_;
   VoiceProcessingAudioUnit::State state_;

sdk/objc/native/src/audio/voice_processing_audio_unit.mm

@@ -72,9 +72,12 @@ static OSStatus GetAGCState(AudioUnit audio_unit, UInt32* enabled) {
   return result;
 }
 
-VoiceProcessingAudioUnit::VoiceProcessingAudioUnit(
+VoiceProcessingAudioUnit::VoiceProcessingAudioUnit(bool bypass_voice_processing,
                                                    VoiceProcessingAudioUnitObserver* observer)
-    : observer_(observer), vpio_unit_(nullptr), state_(kInitRequired) {
+    : bypass_voice_processing_(bypass_voice_processing),
+      observer_(observer),
+      vpio_unit_(nullptr),
+      state_(kInitRequired) {
   RTC_DCHECK(observer);
 }
 
@@ -250,6 +253,24 @@ bool VoiceProcessingAudioUnit::Initialize(Float64 sample_rate) {
     RTCLog(@"Voice Processing I/O unit is now initialized.");
   }
 
+  if (bypass_voice_processing_) {
+    // Attempt to disable builtin voice processing.
+    UInt32 toggle = 1;
+    result = AudioUnitSetProperty(vpio_unit_,
+                                  kAUVoiceIOProperty_BypassVoiceProcessing,
+                                  kAudioUnitScope_Global,
+                                  kInputBus,
+                                  &toggle,
+                                  sizeof(toggle));
+    if (result == noErr) {
+      RTCLog(@"Successfully bypassed voice processing.");
+    } else {
+      RTCLogError(@"Failed to bypass voice processing. Error=%ld.", (long)result);
+    }
+    state_ = kInitialized;
+    return true;
+  }
+
   // AGC should be enabled by default for Voice Processing I/O units but it is
   // checked below and enabled explicitly if needed. This scheme is used
   // to be absolutely sure that the AGC is enabled since we have seen cases

sdk/objc/unittests/RTCAudioDevice_xctest.mm

@@ -33,7 +33,7 @@
   [super setUp];
 
   _audioDeviceModule = webrtc::CreateAudioDeviceModule();
-  _audio_device.reset(new webrtc::ios_adm::AudioDeviceIOS());
+  _audio_device.reset(new webrtc::ios_adm::AudioDeviceIOS(/*bypass_voice_processing=*/false));
   self.audioSession = [RTC_OBJC_TYPE(RTCAudioSession) sharedInstance];
 
   NSError *error = nil;