[WebRTC] Rework device handling sequence so that we can handle unplugging/re-plugging devices (#4593)

* [WebRTC] Rework device handling sequence so that we can handle unplugging/re-plugging devices

The device handling was not processing device updates in the proper sequence as
things like AEC use both input and output devices.  Devices like headsets are both
so unplugging them resulted in various mute conditions and sometimes even a crash.

Now, we update both capture and render devices at once in the proper sequence.

Test Guidance:
* Bring two users in the same place in webrtc regions.
* The 'listening' one should have a headset or something set oas 'Default'
* Press 'talk' on one, and verify the other can hear.
* Unplug the headset from the listening one.
* Validate that audio changes from the headset to the speakers.
* Plug the headset back in.
* Validate that audio changes from speakers to headset.
* Do the same type of test with the headset viewer talking.
* The microphone used should switch from the headset to the computer (it should have one)

Do other various device tests, such as setting devices explicitly, messing with the device selector, etc.

* Fix race condition when multiple change device requests might come in at once

* Update to m137

The primary feature of this commit is to update libwebrtc from m114
to m137.  This is needed to make webrtc buildable, as m114 is not buildable
by the current toolset.

m137 had some changes to the API, which required renaming or changing namespace
of some of the calls.

Additionally, this PR moves from a callback mechanism for gathering the energy
levels for tuning to a wrapper AudioDeviceModule, which gives us more control
over the audio stream.

Finally, the new m137-based webrtc has been updated to allow for 192khz audio
streams.

* Properly pass the observer setting into the inner audio device module

* Update to m137 and get rid of some noise

    This change updates to m137 from m114, which required a few API changes.

    Additionally, this fixes the hiss that happens shortly after someone unmutes: https://github.com/secondlife/server/issues/2094

    There was also an issue with a slight amount of repeated after unmuting if there was audio right before unmuting.  This is because
    the audio processing and buffering still had audio from the previous speaking session.  Now, we inject nearly a half second of
    silence into the audio buffers/processor after unmuting to flush things.

* Install nsis on windows

* Use the newer digital AGC pipeline

m137 improved the AGC pipeline and the existing analog style is going away
so move to the new digital pipeline.

Also, some tweaking for audio levels so that we don't see inworld bars when tuning,
so one's own bars seem a reasonable size, etc.

* Install NSIS during windows sisgning and package build step

* Try pinning the packaging to windows 2022 to deal with missing nsis

* Adjust gain calculation and audio level calculations for tuning and peer connections

* Update with mac universal webrtc build

* Tuning of voice indicators for both tuning mode and inworld for self.

* Redo device deployment to handle cases where multiple deploy requests pile up

Also, mute when leaving webrtc-enabled regions or parcels,
and unmute when voice comes back.

* pre commit issue

6 files changed, 824 insertions, 481 deletions

diff --git a/indra/llwebrtc/CMakeLists.txt b/indra/llwebrtc/CMakeLists.txt
index 4fde489942..eb10f4eee4 100644
--- a/indra/llwebrtc/CMakeLists.txt
+++ b/indra/llwebrtc/CMakeLists.txt
@@ -42,7 +42,7 @@ if (WINDOWS)
                                        iphlpapi
                                        libcmt)
     # as the webrtc libraries are release, build this binary as release as well.
-    target_compile_options(llwebrtc PRIVATE "/MT")
+    target_compile_options(llwebrtc PRIVATE "/MT" "/Zc:wchar_t")
     if (USE_BUGSPLAT)
         set_target_properties(llwebrtc PROPERTIES PDB_OUTPUT_DIRECTORY "${SYMBOLS_STAGING_DIR}")
     endif (USE_BUGSPLAT)
diff --git a/indra/llwebrtc/llwebrtc.cpp b/indra/llwebrtc/llwebrtc.cpp
index 20951ff816..edba2bee9a 100644
--- a/indra/llwebrtc/llwebrtc.cpp
+++ b/indra/llwebrtc/llwebrtc.cpp
@@ -9,7 +9,7 @@
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation;
- * version 2.1 of the License only.
+ * version 2.1 of the License only
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -32,41 +32,79 @@
 #include "api/audio_codecs/audio_encoder_factory.h"
 #include "api/audio_codecs/builtin_audio_decoder_factory.h"
 #include "api/audio_codecs/builtin_audio_encoder_factory.h"
+#include "api/audio/builtin_audio_processing_builder.h"
 #include "api/media_stream_interface.h"
 #include "api/media_stream_track.h"
 #include "modules/audio_processing/audio_buffer.h"
 #include "modules/audio_mixer/audio_mixer_impl.h"
+#include "api/environment/environment_factory.h"
 
 namespace llwebrtc
 {
+#if WEBRTC_WIN
+static int16_t PLAYOUT_DEVICE_DEFAULT = webrtc::AudioDeviceModule::kDefaultDevice;
+static int16_t RECORD_DEVICE_DEFAULT  = webrtc::AudioDeviceModule::kDefaultDevice;
+#else
+static int16_t PLAYOUT_DEVICE_DEFAULT = 0;
+static int16_t RECORD_DEVICE_DEFAULT  = 0;
+#endif
 
-static int16_t PLAYOUT_DEVICE_DEFAULT = -1;
-static int16_t PLAYOUT_DEVICE_BAD     = -2;
-static int16_t RECORD_DEVICE_DEFAULT  = -1;
-static int16_t RECORD_DEVICE_BAD      = -2;
 
-LLAudioDeviceObserver::LLAudioDeviceObserver() : mSumVector {0}, mMicrophoneEnergy(0.0) {}
+//
+// LLWebRTCAudioTransport implementation
+//
 
-float LLAudioDeviceObserver::getMicrophoneEnergy() { return mMicrophoneEnergy; }
+LLWebRTCAudioTransport::LLWebRTCAudioTransport() : mMicrophoneEnergy(0.0)
+{
+    memset(mSumVector, 0, sizeof(mSumVector));
+}
 
-// TODO: Pull smoothing/filtering code into a common helper function
-// for LLAudioDeviceObserver and LLCustomProcessor
+void LLWebRTCAudioTransport::SetEngineTransport(webrtc::AudioTransport* t)
+{
+    engine_.store(t, std::memory_order_release);
+}
 
-void LLAudioDeviceObserver::OnCaptureData(const void    *audio_samples,
-                                          const size_t   num_samples,
-                                          const size_t   bytes_per_sample,
-                                          const size_t   num_channels,
-                                          const uint32_t samples_per_sec)
+int32_t LLWebRTCAudioTransport::RecordedDataIsAvailable(const void* audio_data,
+                                                        size_t      number_of_frames,
+                                                        size_t      bytes_per_frame,
+                                                        size_t      number_of_channels,
+                                                        uint32_t    samples_per_sec,
+                                                        uint32_t    total_delay_ms,
+                                                        int32_t     clock_drift,
+                                                        uint32_t    current_mic_level,
+                                                        bool        key_pressed,
+                                                        uint32_t&   new_mic_level)
 {
+    auto* engine = engine_.load(std::memory_order_acquire);
+
+    // 1) Deliver to engine (authoritative).
+    int32_t ret = 0;
+    if (engine)
+    {
+        ret = engine->RecordedDataIsAvailable(audio_data,
+                                              number_of_frames,
+                                              bytes_per_frame,
+                                              number_of_channels,
+                                              samples_per_sec,
+                                              total_delay_ms,
+                                              clock_drift,
+                                              current_mic_level,
+                                              key_pressed,
+                                              new_mic_level);
+    }
+
+    // 2) Calculate energy for microphone level monitoring
     // calculate the energy
     float        energy  = 0;
-    const short *samples = (const short *) audio_samples;
-    for (size_t index = 0; index < num_samples * num_channels; index++)
+    const short *samples = (const short *) audio_data;
+
+    for (size_t index = 0; index < number_of_frames * number_of_channels; index++)
     {
         float sample = (static_cast<float>(samples[index]) / (float) 32767);
         energy += sample * sample;
     }
-
+    float gain = mGain.load(std::memory_order_relaxed);
+    energy     = energy * gain * gain;
     // smooth it.
     size_t buffer_size = sizeof(mSumVector) / sizeof(mSumVector[0]);
     float  totalSum    = 0;
@@ -78,18 +116,59 @@ void LLAudioDeviceObserver::OnCaptureData(const void    *audio_samples,
     }
     mSumVector[i] = energy;
     totalSum += energy;
-    mMicrophoneEnergy = std::sqrt(totalSum / (num_samples * buffer_size));
+    mMicrophoneEnergy = std::sqrt(totalSum / (number_of_frames * number_of_channels * buffer_size));
+
+    return ret;
 }
 
-void LLAudioDeviceObserver::OnRenderData(const void    *audio_samples,
-                                         const size_t   num_samples,
-                                         const size_t   bytes_per_sample,
-                                         const size_t   num_channels,
-                                         const uint32_t samples_per_sec)
+int32_t LLWebRTCAudioTransport::NeedMorePlayData(size_t   number_of_frames,
+                                                 size_t   bytes_per_frame,
+                                                 size_t   number_of_channels,
+                                                 uint32_t samples_per_sec,
+                                                 void*    audio_data,
+                                                 size_t&  number_of_samples_out,
+                                                 int64_t* elapsed_time_ms,
+                                                 int64_t* ntp_time_ms)
 {
+    auto* engine = engine_.load(std::memory_order_acquire);
+    if (!engine)
+    {
+        // No engine sink; output silence to be safe.
+        const size_t bytes = number_of_frames * bytes_per_frame * number_of_channels;
+        memset(audio_data, 0, bytes);
+        number_of_samples_out = bytes_per_frame;
+        return 0;
+    }
+
+    // Only the engine should fill the buffer.
+    return engine->NeedMorePlayData(number_of_frames,
+                                    bytes_per_frame,
+                                    number_of_channels,
+                                    samples_per_sec,
+                                    audio_data,
+                                    number_of_samples_out,
+                                    elapsed_time_ms,
+                                    ntp_time_ms);
 }
 
-LLCustomProcessor::LLCustomProcessor() : mSampleRateHz(0), mNumChannels(0), mMicrophoneEnergy(0.0), mGain(1.0)
+void LLWebRTCAudioTransport::PullRenderData(int      bits_per_sample,
+                                            int      sample_rate,
+                                            size_t   number_of_channels,
+                                            size_t   number_of_frames,
+                                            void*    audio_data,
+                                            int64_t* elapsed_time_ms,
+                                            int64_t* ntp_time_ms)
+{
+    auto* engine = engine_.load(std::memory_order_acquire);
+
+    if (engine)
+    {
+        engine
+            ->PullRenderData(bits_per_sample, sample_rate, number_of_channels, number_of_frames, audio_data, elapsed_time_ms, ntp_time_ms);
+    }
+}
+
+LLCustomProcessor::LLCustomProcessor(LLCustomProcessorStatePtr state) : mSampleRateHz(0), mNumChannels(0), mState(state)
 {
     memset(mSumVector, 0, sizeof(mSumVector));
 }
@@ -101,40 +180,61 @@ void LLCustomProcessor::Initialize(int sample_rate_hz, int num_channels)
     memset(mSumVector, 0, sizeof(mSumVector));
 }
 
-void LLCustomProcessor::Process(webrtc::AudioBuffer *audio_in)
+void LLCustomProcessor::Process(webrtc::AudioBuffer *audio)
 {
-    webrtc::StreamConfig stream_config;
-    stream_config.set_sample_rate_hz(mSampleRateHz);
-    stream_config.set_num_channels(mNumChannels);
-    std::vector<float *> frame;
-    std::vector<float>   frame_samples;
-
-    if (audio_in->num_channels() < 1 || audio_in->num_frames() < 480)
+    if (audio->num_channels() < 1 || audio->num_frames() < 480)
     {
         return;
     }
 
-    // grab the input audio
-    frame_samples.resize(stream_config.num_samples());
-    frame.resize(stream_config.num_channels());
-    for (size_t ch = 0; ch < stream_config.num_channels(); ++ch)
+    // calculate the energy
+
+    float desired_gain = mState->getGain();
+    if (mState->getDirty())
     {
-        frame[ch] = &(frame_samples)[ch * stream_config.num_frames()];
+        // We'll delay ramping by 30ms in order to clear out buffers that may
+        // have had content before muting.  And for the last 20ms, we'll ramp
+        // down or up smoothly.
+        mRampFrames = 5;
+
+        // we've changed our desired gain, so set the incremental
+        // gain change so that we smoothly step over 20ms
+        mGainStep = (desired_gain - mCurrentGain) / (mSampleRateHz / 50);
     }
 
-    audio_in->CopyTo(stream_config, &frame[0]);
-
-    // calculate the energy
-    float energy = 0;
-    for (size_t index = 0; index < stream_config.num_samples(); index++)
+    if (mRampFrames)
     {
-        float sample = frame_samples[index];
-        sample       = sample * mGain; // apply gain
-        frame_samples[index] = sample; // write processed sample back to buffer.
-        energy += sample * sample;
+        if (mRampFrames-- > 2)
+        {
+            // don't change the gain if we're still in the 'don't move' phase
+            mGainStep = 0.0f;
+        }
+    }
+    else
+    {
+        // We've ramped all the way down, so don't step the gain any more and
+        // just maintaint he current gain.
+        mGainStep = 0.0f;
+        mCurrentGain = desired_gain;
     }
 
-    audio_in->CopyFrom(&frame[0], stream_config);
+    float energy       = 0;
+
+    auto chans = audio->channels();
+    for (size_t ch = 0; ch < audio->num_channels(); ch++)
+    {
+        float* frame_samples = chans[ch];
+        float  gain          = mCurrentGain;
+        for (size_t index = 0; index < audio->num_frames(); index++)
+        {
+            float sample         = frame_samples[index];
+            sample               = sample * gain;    // apply gain
+            frame_samples[index] = sample;        // write processed sample back to buffer.
+            energy += sample * sample;
+            gain += mGainStep;
+        }
+    }
+    mCurrentGain += audio->num_frames() * mGainStep;
 
     // smooth it.
     size_t buffer_size = sizeof(mSumVector) / sizeof(mSumVector[0]);
@@ -147,7 +247,7 @@ void LLCustomProcessor::Process(webrtc::AudioBuffer *audio_in)
     }
     mSumVector[i] = energy;
     totalSum += energy;
-    mMicrophoneEnergy = std::sqrt(totalSum / (stream_config.num_samples() * buffer_size));
+    mState->setMicrophoneEnergy(std::sqrt(totalSum / (audio->num_channels() * audio->num_frames() * buffer_size)));
 }
 
 //
@@ -159,89 +259,54 @@ LLWebRTCImpl::LLWebRTCImpl(LLWebRTCLogCallback* logCallback) :
     mPeerCustomProcessor(nullptr),
     mMute(true),
     mTuningMode(false),
-    mPlayoutDevice(0),
-    mRecordingDevice(0),
-    mTuningAudioDeviceObserver(nullptr)
+    mDevicesDeploying(0),
+    mGain(0.0f)
 {
 }
 
 void LLWebRTCImpl::init()
 {
-    mPlayoutDevice   = 0;
-    mRecordingDevice = 0;
-    rtc::InitializeSSL();
+    webrtc::InitializeSSL();
 
     // Normal logging is rather spammy, so turn it off.
-    rtc::LogMessage::LogToDebug(rtc::LS_NONE);
-    rtc::LogMessage::SetLogToStderr(true);
-    rtc::LogMessage::AddLogToStream(mLogSink, rtc::LS_VERBOSE);
+    webrtc::LogMessage::LogToDebug(webrtc::LS_NONE);
+    webrtc::LogMessage::SetLogToStderr(true);
+    webrtc::LogMessage::AddLogToStream(mLogSink, webrtc::LS_VERBOSE);
 
     mTaskQueueFactory = webrtc::CreateDefaultTaskQueueFactory();
 
     // Create the native threads.
-    mNetworkThread = rtc::Thread::CreateWithSocketServer();
+    mNetworkThread = webrtc::Thread::CreateWithSocketServer();
     mNetworkThread->SetName("WebRTCNetworkThread", nullptr);
     mNetworkThread->Start();
-    mWorkerThread = rtc::Thread::Create();
+    mWorkerThread = webrtc::Thread::Create();
     mWorkerThread->SetName("WebRTCWorkerThread", nullptr);
     mWorkerThread->Start();
-    mSignalingThread = rtc::Thread::Create();
+    mSignalingThread = webrtc::Thread::Create();
     mSignalingThread->SetName("WebRTCSignalingThread", nullptr);
     mSignalingThread->Start();
 
-    mTuningAudioDeviceObserver = new LLAudioDeviceObserver;
-    mWorkerThread->PostTask(
-        [this]()
-        {
-            // Initialize the audio devices on the Worker Thread
-            mTuningDeviceModule =
-                webrtc::CreateAudioDeviceWithDataObserver(webrtc::AudioDeviceModule::AudioLayer::kPlatformDefaultAudio,
-                                                          mTaskQueueFactory.get(),
-                                                          std::unique_ptr<webrtc::AudioDeviceDataObserver>(mTuningAudioDeviceObserver));
-
-            mTuningDeviceModule->Init();
-            mTuningDeviceModule->SetPlayoutDevice(mPlayoutDevice);
-            mTuningDeviceModule->SetRecordingDevice(mRecordingDevice);
-            mTuningDeviceModule->EnableBuiltInAEC(false);
-            mTuningDeviceModule->SetAudioDeviceSink(this);
-            mTuningDeviceModule->InitMicrophone();
-            mTuningDeviceModule->InitSpeaker();
-            mTuningDeviceModule->SetStereoRecording(false);
-            mTuningDeviceModule->SetStereoPlayout(true);
-            mTuningDeviceModule->InitRecording();
-            mTuningDeviceModule->InitPlayout();
-            updateDevices();
-        });
-
     mWorkerThread->BlockingCall(
         [this]()
         {
-            // the peer device module doesn't need an observer
-            // as we pull peer data after audio processing.
-            mPeerDeviceModule = webrtc::CreateAudioDeviceWithDataObserver(webrtc::AudioDeviceModule::AudioLayer::kPlatformDefaultAudio,
-                                                                          mTaskQueueFactory.get(),
-                                                                          nullptr);
-            mPeerDeviceModule->Init();
-            mPeerDeviceModule->SetPlayoutDevice(mPlayoutDevice);
-            mPeerDeviceModule->SetRecordingDevice(mRecordingDevice);
-            mPeerDeviceModule->EnableBuiltInAEC(false);
-            mPeerDeviceModule->InitMicrophone();
-            mPeerDeviceModule->InitSpeaker();
+            webrtc::scoped_refptr<webrtc::AudioDeviceModule> realADM =
+                webrtc::AudioDeviceModule::Create(webrtc::AudioDeviceModule::AudioLayer::kPlatformDefaultAudio, mTaskQueueFactory.get());
+            mDeviceModule = webrtc::make_ref_counted<LLWebRTCAudioDeviceModule>(realADM);
+            mDeviceModule->SetObserver(this);
         });
 
     // The custom processor allows us to retrieve audio data (and levels)
     // from after other audio processing such as AEC, AGC, etc.
-    mPeerCustomProcessor = new LLCustomProcessor;
-    webrtc::AudioProcessingBuilder apb;
-    apb.SetCapturePostProcessing(std::unique_ptr<webrtc::CustomProcessing>(mPeerCustomProcessor));
-    mAudioProcessingModule = apb.Create();
+    mPeerCustomProcessor = std::make_shared<LLCustomProcessorState>();
+    webrtc::BuiltinAudioProcessingBuilder apb;
+    apb.SetCapturePostProcessing(std::make_unique<LLCustomProcessor>(mPeerCustomProcessor));
+    mAudioProcessingModule = apb.Build(webrtc::CreateEnvironment());
 
     webrtc::AudioProcessing::Config apm_config;
     apm_config.echo_canceller.enabled         = false;
     apm_config.echo_canceller.mobile_mode     = false;
     apm_config.gain_controller1.enabled       = false;
-    apm_config.gain_controller1.mode          = webrtc::AudioProcessing::Config::GainController1::kAdaptiveAnalog;
-    apm_config.gain_controller2.enabled       = false;
+    apm_config.gain_controller2.enabled       = true;
     apm_config.high_pass_filter.enabled       = true;
     apm_config.noise_suppression.enabled      = true;
     apm_config.noise_suppression.level        = webrtc::AudioProcessing::Config::NoiseSuppression::kVeryHigh;
@@ -252,6 +317,7 @@ void LLWebRTCImpl::init()
     mAudioProcessingModule->ApplyConfig(apm_config);
 
     webrtc::ProcessingConfig processing_config;
+
     processing_config.input_stream().set_num_channels(2);
     processing_config.input_stream().set_sample_rate_hz(48000);
     processing_config.output_stream().set_num_channels(2);
@@ -266,13 +332,19 @@ void LLWebRTCImpl::init()
     mPeerConnectionFactory = webrtc::CreatePeerConnectionFactory(mNetworkThread.get(),
                                                                  mWorkerThread.get(),
                                                                  mSignalingThread.get(),
-                                                                 mPeerDeviceModule,
+                                                                 mDeviceModule,
                                                                  webrtc::CreateBuiltinAudioEncoderFactory(),
                                                                  webrtc::CreateBuiltinAudioDecoderFactory(),
                                                                  nullptr /* video_encoder_factory */,
                                                                  nullptr /* video_decoder_factory */,
                                                                  nullptr /* audio_mixer */,
                                                                  mAudioProcessingModule);
+    mWorkerThread->PostTask(
+        [this]()
+        {
+            mDeviceModule->EnableBuiltInAEC(false);
+            updateDevices();
+        });
 
 }
 
@@ -294,64 +366,16 @@ void LLWebRTCImpl::terminate()
     mWorkerThread->BlockingCall(
         [this]()
         {
-            if (mTuningDeviceModule)
-            {
-                mTuningDeviceModule->StopRecording();
-                mTuningDeviceModule->Terminate();
-            }
-            if (mPeerDeviceModule)
+            if (mDeviceModule)
             {
-                mPeerDeviceModule->StopRecording();
-                mPeerDeviceModule->Terminate();
-            }
-            mTuningDeviceModule = nullptr;
-            mPeerDeviceModule   = nullptr;
-            mTaskQueueFactory   = nullptr;
-        });
-    rtc::LogMessage::RemoveLogToStream(mLogSink);
-}
-
-//
-// Devices functions
-//
-// Most device-related functionality needs to happen
-// on the worker thread (the audio thread,) so those calls will be
-// proxied over to that thread.
-//
-void LLWebRTCImpl::setRecording(bool recording)
-{
-    mWorkerThread->PostTask(
-        [this, recording]()
-        {
-            if (recording)
-            {
-                mPeerDeviceModule->SetStereoRecording(false);
-                mPeerDeviceModule->InitRecording();
-                mPeerDeviceModule->StartRecording();
-            }
-            else
-            {
-                mPeerDeviceModule->StopRecording();
-            }
-        });
-}
-
-void LLWebRTCImpl::setPlayout(bool playing)
-{
-    mWorkerThread->PostTask(
-        [this, playing]()
-        {
-            if (playing)
-            {
-                mPeerDeviceModule->SetStereoPlayout(true);
-                mPeerDeviceModule->InitPlayout();
-                mPeerDeviceModule->StartPlayout();
-            }
-            else
-            {
-                mPeerDeviceModule->StopPlayout();
+                mDeviceModule->StopRecording();
+                mDeviceModule->StopPlayout();
+                mDeviceModule->Terminate();
             }
+            mDeviceModule     = nullptr;
+            mTaskQueueFactory = nullptr;
         });
+    webrtc::LogMessage::RemoveLogToStream(mLogSink);
 }
 
 void LLWebRTCImpl::setAudioConfig(LLWebRTCDeviceInterface::AudioConfig config)
@@ -359,9 +383,9 @@ void LLWebRTCImpl::setAudioConfig(LLWebRTCDeviceInterface::AudioConfig config)
     webrtc::AudioProcessing::Config apm_config;
     apm_config.echo_canceller.enabled         = config.mEchoCancellation;
     apm_config.echo_canceller.mobile_mode     = false;
-    apm_config.gain_controller1.enabled       = config.mAGC;
-    apm_config.gain_controller1.mode          = webrtc::AudioProcessing::Config::GainController1::kAdaptiveAnalog;
-    apm_config.gain_controller2.enabled       = false;
+    apm_config.gain_controller1.enabled       = false;
+    apm_config.gain_controller2.enabled       = config.mAGC;
+    apm_config.gain_controller2.adaptive_digital.enabled = true; // auto-level speech
     apm_config.high_pass_filter.enabled       = true;
     apm_config.transient_suppression.enabled  = true;
     apm_config.pipeline.multi_channel_render  = true;
@@ -414,142 +438,134 @@ void LLWebRTCImpl::unsetDevicesObserver(LLWebRTCDevicesObserver *observer)
     }
 }
 
-void ll_set_device_module_capture_device(rtc::scoped_refptr<webrtc::AudioDeviceModule> device_module, int16_t device)
+// must be run in the worker thread.
+void LLWebRTCImpl::workerDeployDevices()
 {
+    int16_t recordingDevice = RECORD_DEVICE_DEFAULT;
 #if WEBRTC_WIN
-    if (device < 0)
-    {
-        device_module->SetRecordingDevice(webrtc::AudioDeviceModule::kDefaultDevice);
-    }
-    else
-    {
-        device_module->SetRecordingDevice(device);
-    }
+    int16_t recording_device_start = 0;
 #else
-    // passed in default is -1, but the device list
-    // has it at 0
-    device_module->SetRecordingDevice(device + 1);
+    int16_t recording_device_start = 1;
 #endif
-    device_module->InitMicrophone();
-}
 
-void LLWebRTCImpl::setCaptureDevice(const std::string &id)
-{
-    int16_t recordingDevice = RECORD_DEVICE_DEFAULT;
-    if (id != "Default")
+    if (mRecordingDevice != "Default")
     {
-        for (int16_t i = 0; i < mRecordingDeviceList.size(); i++)
+        for (int16_t i = recording_device_start; i < mRecordingDeviceList.size(); i++)
         {
-            if (mRecordingDeviceList[i].mID == id)
+            if (mRecordingDeviceList[i].mID == mRecordingDevice)
             {
                 recordingDevice = i;
                 break;
             }
         }
     }
-    if (recordingDevice == mRecordingDevice)
-    {
-        return;
-    }
-    mRecordingDevice = recordingDevice;
-    if (mTuningMode)
-    {
-        mWorkerThread->PostTask([this, recordingDevice]()
-            {
-                ll_set_device_module_capture_device(mTuningDeviceModule, recordingDevice);
-            });
-    }
-    else
-    {
-        mWorkerThread->PostTask([this, recordingDevice]()
-            {
-                bool recording = mPeerDeviceModule->Recording();
-                if (recording)
-                {
-                    mPeerDeviceModule->StopRecording();
-                }
-                ll_set_device_module_capture_device(mPeerDeviceModule, recordingDevice);
-                if (recording)
-                {
-                    mPeerDeviceModule->SetStereoRecording(false);
-                    mPeerDeviceModule->InitRecording();
-                    mPeerDeviceModule->StartRecording();
-                }
-            });
-    }
-}
 
-
-void ll_set_device_module_render_device(rtc::scoped_refptr<webrtc::AudioDeviceModule> device_module, int16_t device)
-{
+    mDeviceModule->StopPlayout();
+    mDeviceModule->ForceStopRecording();
 #if WEBRTC_WIN
-    if (device < 0)
+    if (recordingDevice < 0)
     {
-        device_module->SetPlayoutDevice(webrtc::AudioDeviceModule::kDefaultDevice);
+        mDeviceModule->SetRecordingDevice((webrtc::AudioDeviceModule::WindowsDeviceType)recordingDevice);
     }
     else
     {
-        device_module->SetPlayoutDevice(device);
+        mDeviceModule->SetRecordingDevice(recordingDevice);
     }
 #else
-    device_module->SetPlayoutDevice(device + 1);
+    mDeviceModule->SetRecordingDevice(recordingDevice);
 #endif
-    device_module->InitSpeaker();
-}
+    mDeviceModule->InitMicrophone();
+    mDeviceModule->SetStereoRecording(false);
+    mDeviceModule->InitRecording();
 
-void LLWebRTCImpl::setRenderDevice(const std::string &id)
-{
     int16_t playoutDevice = PLAYOUT_DEVICE_DEFAULT;
-    if (id != "Default")
+#if WEBRTC_WIN
+    int16_t playout_device_start = 0;
+#else
+    int16_t playout_device_start = 1;
+#endif
+    if (mPlayoutDevice != "Default")
     {
-        for (int16_t i = 0; i < mPlayoutDeviceList.size(); i++)
+        for (int16_t i = playout_device_start; i < mPlayoutDeviceList.size(); i++)
         {
-            if (mPlayoutDeviceList[i].mID == id)
+            if (mPlayoutDeviceList[i].mID == mPlayoutDevice)
             {
                 playoutDevice = i;
                 break;
             }
         }
     }
-    if (playoutDevice == mPlayoutDevice)
+
+#if WEBRTC_WIN
+    if (playoutDevice < 0)
     {
-        return;
+        mDeviceModule->SetPlayoutDevice((webrtc::AudioDeviceModule::WindowsDeviceType)playoutDevice);
+    }
+    else
+    {
+        mDeviceModule->SetPlayoutDevice(playoutDevice);
     }
-    mPlayoutDevice = playoutDevice;
+#else
+    mDeviceModule->SetPlayoutDevice(playoutDevice);
+#endif
+    mDeviceModule->InitSpeaker();
+    mDeviceModule->SetStereoPlayout(true);
+    mDeviceModule->InitPlayout();
 
-    if (mTuningMode)
+    if ((!mMute && mPeerConnections.size()) || mTuningMode)
     {
-        mWorkerThread->PostTask(
-            [this, playoutDevice]()
-            {
-                ll_set_device_module_render_device(mTuningDeviceModule, playoutDevice);
-            });
+        mDeviceModule->ForceStartRecording();
     }
-    else
+
+    if (!mTuningMode)
     {
-        mWorkerThread->PostTask(
-            [this, playoutDevice]()
+        mDeviceModule->StartPlayout();
+    }
+    mSignalingThread->PostTask(
+        [this]
+        {
+            for (auto& connection : mPeerConnections)
             {
-                bool playing = mPeerDeviceModule->Playing();
-                if (playing)
+                if (mTuningMode)
                 {
-                    mPeerDeviceModule->StopPlayout();
+                    connection->enableSenderTracks(false);
                 }
-                ll_set_device_module_render_device(mPeerDeviceModule, playoutDevice);
-                if (playing)
+                else
                 {
-                    mPeerDeviceModule->SetStereoPlayout(true);
-                    mPeerDeviceModule->InitPlayout();
-                    mPeerDeviceModule->StartPlayout();
+                    connection->resetMute();
                 }
-            });
+                connection->enableReceiverTracks(!mTuningMode);
+            }
+            if (1 < mDevicesDeploying.fetch_sub(1, std::memory_order_relaxed))
+            {
+                mWorkerThread->PostTask([this] { workerDeployDevices(); });
+            }
+        });
+}
+
+void LLWebRTCImpl::setCaptureDevice(const std::string &id)
+{
+
+    if (mRecordingDevice != id)
+    {
+        mRecordingDevice = id;
+        deployDevices();
+    }
+}
+
+void LLWebRTCImpl::setRenderDevice(const std::string &id)
+{
+    if (mPlayoutDevice != id)
+    {
+        mPlayoutDevice = id;
+        deployDevices();
     }
 }
 
 // updateDevices needs to happen on the worker thread.
 void LLWebRTCImpl::updateDevices()
 {
-    int16_t renderDeviceCount  = mTuningDeviceModule->PlayoutDevices();
+    int16_t renderDeviceCount  = mDeviceModule->PlayoutDevices();
 
     mPlayoutDeviceList.clear();
 #if WEBRTC_WIN
@@ -563,11 +579,11 @@ void LLWebRTCImpl::updateDevices()
     {
         char name[webrtc::kAdmMaxDeviceNameSize];
         char guid[webrtc::kAdmMaxGuidSize];
-        mTuningDeviceModule->PlayoutDeviceName(index, name, guid);
+        mDeviceModule->PlayoutDeviceName(index, name, guid);
         mPlayoutDeviceList.emplace_back(name, guid);
     }
 
-    int16_t captureDeviceCount        = mTuningDeviceModule->RecordingDevices();
+    int16_t captureDeviceCount        = mDeviceModule->RecordingDevices();
 
     mRecordingDeviceList.clear();
 #if WEBRTC_WIN
@@ -581,7 +597,7 @@ void LLWebRTCImpl::updateDevices()
     {
         char name[webrtc::kAdmMaxDeviceNameSize];
         char guid[webrtc::kAdmMaxGuidSize];
-        mTuningDeviceModule->RecordingDeviceName(index, name, guid);
+        mDeviceModule->RecordingDeviceName(index, name, guid);
         mRecordingDeviceList.emplace_back(name, guid);
     }
 
@@ -593,11 +609,7 @@ void LLWebRTCImpl::updateDevices()
 
 void LLWebRTCImpl::OnDevicesUpdated()
 {
-    // reset these to a bad value so an update is forced
-    mRecordingDevice = RECORD_DEVICE_BAD;
-    mPlayoutDevice   = PLAYOUT_DEVICE_BAD;
-
-    updateDevices();
+    deployDevices();
 }
 
 
@@ -605,60 +617,109 @@ void LLWebRTCImpl::setTuningMode(bool enable)
 {
     mTuningMode = enable;
     mWorkerThread->PostTask(
-        [this, enable] {
-            if (enable)
-            {
-                mPeerDeviceModule->StopRecording();
-                mPeerDeviceModule->StopPlayout();
-                ll_set_device_module_render_device(mTuningDeviceModule, mPlayoutDevice);
-                ll_set_device_module_capture_device(mTuningDeviceModule, mRecordingDevice);
-                mTuningDeviceModule->InitPlayout();
-                mTuningDeviceModule->InitRecording();
-                mTuningDeviceModule->StartRecording();
-                // TODO:  Starting Playout on the TDM appears to create an audio artifact (click)
-                // in this case, so disabling it for now.  We may have to do something different
-                // if we enable 'echo playback' via the TDM when tuning.
-                //mTuningDeviceModule->StartPlayout();
-            }
-            else
-            {
-                mTuningDeviceModule->StopRecording();
-                //mTuningDeviceModule->StopPlayout();
-                ll_set_device_module_render_device(mPeerDeviceModule, mPlayoutDevice);
-                ll_set_device_module_capture_device(mPeerDeviceModule, mRecordingDevice);
-                mPeerDeviceModule->SetStereoPlayout(true);
-                mPeerDeviceModule->SetStereoRecording(false);
-                mPeerDeviceModule->InitPlayout();
-                mPeerDeviceModule->InitRecording();
-                mPeerDeviceModule->StartPlayout();
-                mPeerDeviceModule->StartRecording();
-            }
-        }
-    );
-    mSignalingThread->PostTask(
-        [this, enable]
+        [this]
         {
-            for (auto &connection : mPeerConnections)
-            {
-                if (enable)
+            mDeviceModule->SetTuning(mTuningMode, mMute);
+            mSignalingThread->PostTask(
+                [this]
                 {
-                    connection->enableSenderTracks(false);
-                }
-                else
-                {
-                    connection->resetMute();
-                }
-                connection->enableReceiverTracks(!enable);
-            }
+                    for (auto& connection : mPeerConnections)
+                    {
+                        if (mTuningMode)
+                        {
+                            connection->enableSenderTracks(false);
+                        }
+                        else
+                        {
+                            connection->resetMute();
+                        }
+                        connection->enableReceiverTracks(!mTuningMode);
+                    }
+                });
+        });
+}
+
+void LLWebRTCImpl::deployDevices()
+{
+    if (0 < mDevicesDeploying.fetch_add(1, std::memory_order_relaxed))
+    {
+        return;
+    }
+    mWorkerThread->PostTask(
+        [this] {
+            workerDeployDevices();
         });
 }
 
-float LLWebRTCImpl::getTuningAudioLevel() { return -20 * log10f(mTuningAudioDeviceObserver->getMicrophoneEnergy()); }
+float LLWebRTCImpl::getTuningAudioLevel()
+{
+    return mDeviceModule ? -20 * log10f(mDeviceModule->GetMicrophoneEnergy()) : std::numeric_limits<float>::infinity();
+}
 
-float LLWebRTCImpl::getPeerConnectionAudioLevel() { return -20 * log10f(mPeerCustomProcessor->getMicrophoneEnergy()); }
+void LLWebRTCImpl::setTuningMicGain(float gain)
+{
+    if (mTuningMode && mDeviceModule)
+    {
+        mDeviceModule->SetTuningMicGain(gain);
+    }
+}
+
+float LLWebRTCImpl::getPeerConnectionAudioLevel()
+{
+    return mTuningMode ? std::numeric_limits<float>::infinity()
+                       : (mPeerCustomProcessor ? -20 * log10f(mPeerCustomProcessor->getMicrophoneEnergy())
+                                               : std::numeric_limits<float>::infinity());
+}
 
-void LLWebRTCImpl::setPeerConnectionGain(float gain) { mPeerCustomProcessor->setGain(gain); }
+void LLWebRTCImpl::setMicGain(float gain)
+{
+    mGain = gain;
+    if (!mTuningMode && mPeerCustomProcessor)
+    {
+        mPeerCustomProcessor->setGain(gain);
+    }
+}
 
+void LLWebRTCImpl::setMute(bool mute, int delay_ms)
+{
+    if (mMute != mute)
+    {
+        mMute = mute;
+        intSetMute(mute, delay_ms);
+    }
+}
+
+void LLWebRTCImpl::intSetMute(bool mute, int delay_ms)
+{
+    if (mPeerCustomProcessor)
+    {
+        mPeerCustomProcessor->setGain(mMute ? 0.0f : mGain);
+    }
+    if (mMute)
+    {
+        mWorkerThread->PostDelayedTask(
+            [this]
+            {
+                if (mDeviceModule)
+                {
+                    mDeviceModule->ForceStopRecording();
+                }
+            },
+            webrtc::TimeDelta::Millis(delay_ms));
+    }
+    else
+    {
+        mWorkerThread->PostTask(
+            [this]
+            {
+                if (mDeviceModule)
+                {
+                    mDeviceModule->InitRecording();
+                    mDeviceModule->ForceStartRecording();
+                }
+            });
+    }
+}
 
 //
 // Peer Connection Helpers
@@ -666,34 +727,31 @@ void LLWebRTCImpl::setPeerConnectionGain(float gain) { mPeerCustomProcessor->set
 
 LLWebRTCPeerConnectionInterface *LLWebRTCImpl::newPeerConnection()
 {
-    rtc::scoped_refptr<LLWebRTCPeerConnectionImpl> peerConnection = rtc::scoped_refptr<LLWebRTCPeerConnectionImpl>(new rtc::RefCountedObject<LLWebRTCPeerConnectionImpl>());
+    bool empty = mPeerConnections.empty();
+    webrtc::scoped_refptr<LLWebRTCPeerConnectionImpl> peerConnection = webrtc::scoped_refptr<LLWebRTCPeerConnectionImpl>(new webrtc::RefCountedObject<LLWebRTCPeerConnectionImpl>());
     peerConnection->init(this);
-
-    mPeerConnections.emplace_back(peerConnection);
-    // Should it really start disabled?
-    // Seems like something doesn't get the memo and senders need to be reset later
-    // to remove the voice indicator from taskbar
-    peerConnection->enableSenderTracks(false);
     if (mPeerConnections.empty())
     {
-        setRecording(true);
-        setPlayout(true);
+        intSetMute(mMute);
     }
+    mPeerConnections.emplace_back(peerConnection);
+
+    peerConnection->enableSenderTracks(false);
+    peerConnection->resetMute();
     return peerConnection.get();
 }
 
 void LLWebRTCImpl::freePeerConnection(LLWebRTCPeerConnectionInterface* peer_connection)
 {
-    std::vector<rtc::scoped_refptr<LLWebRTCPeerConnectionImpl>>::iterator it =
+    std::vector<webrtc::scoped_refptr<LLWebRTCPeerConnectionImpl>>::iterator it =
     std::find(mPeerConnections.begin(), mPeerConnections.end(), peer_connection);
     if (it != mPeerConnections.end())
     {
         mPeerConnections.erase(it);
-    }
-    if (mPeerConnections.empty())
-    {
-        setRecording(false);
-        setPlayout(false);
+        if (mPeerConnections.empty())
+        {
+            intSetMute(true);
+        }
     }
 }
 
@@ -729,7 +787,7 @@ void LLWebRTCPeerConnectionImpl::init(LLWebRTCImpl * webrtc_impl)
 }
 void LLWebRTCPeerConnectionImpl::terminate()
 {
-    mWebRTCImpl->SignalingBlockingCall(
+    mWebRTCImpl->PostSignalingTask(
         [this]()
         {
             if (mPeerConnection)
@@ -753,7 +811,6 @@ void LLWebRTCPeerConnectionImpl::terminate()
                         track->set_enabled(false);
                     }
                 }
-                mPeerConnection->SetAudioRecording(false);
 
                 mPeerConnection->Close();
                 if (mLocalStream)
@@ -840,7 +897,7 @@ bool LLWebRTCPeerConnectionImpl::initializeConnection(const LLWebRTCPeerConnecti
                 mDataChannel->RegisterObserver(this);
             }
 
-            cricket::AudioOptions audioOptions;
+            webrtc::AudioOptions audioOptions;
             audioOptions.auto_gain_control = true;
             audioOptions.echo_cancellation = true;
             audioOptions.noise_suppression = true;
@@ -848,7 +905,7 @@ bool LLWebRTCPeerConnectionImpl::initializeConnection(const LLWebRTCPeerConnecti
 
             mLocalStream = mPeerConnectionFactory->CreateLocalMediaStream("SLStream");
 
-            rtc::scoped_refptr<webrtc::AudioTrackInterface> audio_track(
+            webrtc::scoped_refptr<webrtc::AudioTrackInterface> audio_track(
                 mPeerConnectionFactory->CreateAudioTrack("SLAudio", mPeerConnectionFactory->CreateAudioSource(audioOptions).get()));
             audio_track->set_enabled(false);
             mLocalStream->AddTrack(audio_track);
@@ -862,7 +919,7 @@ bool LLWebRTCPeerConnectionImpl::initializeConnection(const LLWebRTCPeerConnecti
                 webrtc::RtpParameters      params;
                 webrtc::RtpCodecParameters codecparam;
                 codecparam.name                       = "opus";
-                codecparam.kind                       = cricket::MEDIA_TYPE_AUDIO;
+                codecparam.kind                       = webrtc::MediaType::AUDIO;
                 codecparam.clock_rate                 = 48000;
                 codecparam.num_channels               = 2;
                 codecparam.parameters["stereo"]       = "1";
@@ -877,7 +934,7 @@ bool LLWebRTCPeerConnectionImpl::initializeConnection(const LLWebRTCPeerConnecti
                 webrtc::RtpParameters      params;
                 webrtc::RtpCodecParameters codecparam;
                 codecparam.name                       = "opus";
-                codecparam.kind                       = cricket::MEDIA_TYPE_AUDIO;
+                codecparam.kind                       = webrtc::MediaType::AUDIO;
                 codecparam.clock_rate                 = 48000;
                 codecparam.num_channels               = 2;
                 codecparam.parameters["stereo"]       = "1";
@@ -904,7 +961,6 @@ void LLWebRTCPeerConnectionImpl::enableSenderTracks(bool enable)
     // set_enabled shouldn't be done on the worker thread.
     if (mPeerConnection)
     {
-        mPeerConnection->SetAudioRecording(enable);
         auto senders = mPeerConnection->GetSenders();
         for (auto &sender : senders)
         {
@@ -938,7 +994,7 @@ void LLWebRTCPeerConnectionImpl::AnswerAvailable(const std::string &sdp)
                                    {
                                        RTC_LOG(LS_INFO) << __FUNCTION__ << " " << mPeerConnection->peer_connection_state();
                                        mPeerConnection->SetRemoteDescription(webrtc::CreateSessionDescription(webrtc::SdpType::kAnswer, sdp),
-                                                                             rtc::scoped_refptr<webrtc::SetRemoteDescriptionObserverInterface>(this));
+                                                                             webrtc::scoped_refptr<webrtc::SetRemoteDescriptionObserverInterface>(this));
                                    }
                                });
 }
@@ -951,22 +1007,22 @@ void LLWebRTCPeerConnectionImpl::AnswerAvailable(const std::string &sdp)
 void LLWebRTCPeerConnectionImpl::setMute(bool mute)
 {
     EMicMuteState new_state = mute ? MUTE_MUTED : MUTE_UNMUTED;
-    if (new_state == mMute)
-    {
-        return; // no change
-    }
+
+    // even if mute hasn't changed, we still need to update the mute
+    // state on the connections to handle cases where the 'Default' device
+    // has changed in the OS (unplugged headset, etc.) which messes
+    // with the mute state.
+
     bool force_reset = mMute == MUTE_INITIAL && mute;
     bool enable = !mute;
     mMute = new_state;
 
+
     mWebRTCImpl->PostSignalingTask(
         [this, force_reset, enable]()
         {
         if (mPeerConnection)
         {
-            // SetAudioRecording must be called before enabling/disabling tracks.
-            mPeerConnection->SetAudioRecording(enable);
-
             auto senders = mPeerConnection->GetSenders();
 
             RTC_LOG(LS_INFO) << __FUNCTION__ << (mMute ? "disabling" : "enabling") << " streams count " << senders.size();
@@ -1046,14 +1102,14 @@ void LLWebRTCPeerConnectionImpl::setSendVolume(float volume)
 // PeerConnectionObserver implementation.
 //
 
-void LLWebRTCPeerConnectionImpl::OnAddTrack(rtc::scoped_refptr<webrtc::RtpReceiverInterface>                     receiver,
-                                            const std::vector<rtc::scoped_refptr<webrtc::MediaStreamInterface>> &streams)
+void LLWebRTCPeerConnectionImpl::OnAddTrack(webrtc::scoped_refptr<webrtc::RtpReceiverInterface>                     receiver,
+                                            const std::vector<webrtc::scoped_refptr<webrtc::MediaStreamInterface>> &streams)
 {
     RTC_LOG(LS_INFO) << __FUNCTION__ << " " << receiver->id();
     webrtc::RtpParameters      params;
     webrtc::RtpCodecParameters codecparam;
     codecparam.name                       = "opus";
-    codecparam.kind                       = cricket::MEDIA_TYPE_AUDIO;
+    codecparam.kind                       = webrtc::MediaType::AUDIO;
     codecparam.clock_rate                 = 48000;
     codecparam.num_channels               = 2;
     codecparam.parameters["stereo"]       = "1";
@@ -1062,12 +1118,12 @@ void LLWebRTCPeerConnectionImpl::OnAddTrack(rtc::scoped_refptr<webrtc::RtpReceiv
     receiver->SetParameters(params);
 }
 
-void LLWebRTCPeerConnectionImpl::OnRemoveTrack(rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver)
+void LLWebRTCPeerConnectionImpl::OnRemoveTrack(webrtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver)
 {
     RTC_LOG(LS_INFO) << __FUNCTION__ << " " << receiver->id();
 }
 
-void LLWebRTCPeerConnectionImpl::OnDataChannel(rtc::scoped_refptr<webrtc::DataChannelInterface> channel)
+void LLWebRTCPeerConnectionImpl::OnDataChannel(webrtc::scoped_refptr<webrtc::DataChannelInterface> channel)
 {
     if (mDataChannel)
     {
@@ -1154,23 +1210,23 @@ static std::string iceCandidateToTrickleString(const webrtc::IceCandidateInterfa
     candidate->candidate().address().ipaddr().ToString() << " " <<
     candidate->candidate().address().PortAsString() << " typ ";
 
-    if (candidate->candidate().type() == cricket::LOCAL_PORT_TYPE)
+    if (candidate->candidate().type() == webrtc::IceCandidateType::kHost)
     {
         candidate_stream << "host";
     }
-    else if (candidate->candidate().type() == cricket::STUN_PORT_TYPE)
+    else if (candidate->candidate().type() == webrtc::IceCandidateType::kSrflx)
     {
         candidate_stream << "srflx " <<
         "raddr " << candidate->candidate().related_address().ipaddr().ToString() << " " <<
         "rport " << candidate->candidate().related_address().PortAsString();
     }
-    else if (candidate->candidate().type() == cricket::RELAY_PORT_TYPE)
+    else if (candidate->candidate().type() == webrtc::IceCandidateType::kRelay)
     {
         candidate_stream << "relay " <<
         "raddr " << candidate->candidate().related_address().ipaddr().ToString() << " " <<
         "rport " << candidate->candidate().related_address().PortAsString();
     }
-    else if (candidate->candidate().type() == cricket::PRFLX_PORT_TYPE)
+    else if (candidate->candidate().type() == webrtc::IceCandidateType::kPrflx)
     {
         candidate_stream << "prflx " <<
         "raddr " << candidate->candidate().related_address().ipaddr().ToString() << " " <<
@@ -1265,7 +1321,7 @@ void LLWebRTCPeerConnectionImpl::OnSuccess(webrtc::SessionDescriptionInterface *
 
    mPeerConnection->SetLocalDescription(std::unique_ptr<webrtc::SessionDescriptionInterface>(
                                                      webrtc::CreateSessionDescription(webrtc::SdpType::kOffer, mangled_sdp)),
-                                                 rtc::scoped_refptr<webrtc::SetLocalDescriptionObserverInterface>(this));
+                                                 webrtc::scoped_refptr<webrtc::SetLocalDescriptionObserverInterface>(this));
 
 }
 
@@ -1375,7 +1431,7 @@ void LLWebRTCPeerConnectionImpl::sendData(const std::string& data, bool binary)
 {
     if (mDataChannel)
     {
-        rtc::CopyOnWriteBuffer cowBuffer(data.data(), data.length());
+        webrtc::CopyOnWriteBuffer cowBuffer(data.data(), data.length());
         webrtc::DataBuffer     buffer(cowBuffer, binary);
         mWebRTCImpl->PostNetworkTask([this, buffer]() {
                 if (mDataChannel)
diff --git a/indra/llwebrtc/llwebrtc.h b/indra/llwebrtc/llwebrtc.h
index c6fdb909dd..7d06b7d2b4 100644
--- a/indra/llwebrtc/llwebrtc.h
+++ b/indra/llwebrtc/llwebrtc.h
@@ -159,7 +159,10 @@ class LLWebRTCDeviceInterface
     virtual void setTuningMode(bool enable) = 0;
     virtual float getTuningAudioLevel() = 0; // for use during tuning
     virtual float getPeerConnectionAudioLevel() = 0; // for use when not tuning
-    virtual void setPeerConnectionGain(float gain) = 0;
+    virtual void setMicGain(float gain) = 0;
+    virtual void setTuningMicGain(float gain)        = 0;
+
+    virtual void setMute(bool mute, int delay_ms = 0) = 0;
 };
 
 // LLWebRTCAudioInterface provides the viewer with a way
diff --git a/indra/llwebrtc/llwebrtc_impl.h b/indra/llwebrtc/llwebrtc_impl.h
index b6294dbd4a..51d42c82b2 100644
--- a/indra/llwebrtc/llwebrtc_impl.h
+++ b/indra/llwebrtc/llwebrtc_impl.h
@@ -54,12 +54,12 @@
 #include "rtc_base/ref_counted_object.h"
 #include "rtc_base/ssl_adapter.h"
 #include "rtc_base/thread.h"
+#include "rtc_base/logging.h"
 #include "api/peer_connection_interface.h"
 #include "api/media_stream_interface.h"
 #include "api/create_peerconnection_factory.h"
 #include "modules/audio_device/include/audio_device.h"
 #include "modules/audio_device/include/audio_device_data_observer.h"
-#include "rtc_base/task_queue.h"
 #include "api/task_queue/task_queue_factory.h"
 #include "api/task_queue/default_task_queue_factory.h"
 #include "modules/audio_device/include/audio_device_defines.h"
@@ -69,35 +69,30 @@ namespace llwebrtc
 
 class LLWebRTCPeerConnectionImpl;
 
-class LLWebRTCLogSink : public rtc::LogSink {
+class LLWebRTCLogSink : public webrtc::LogSink
+{
 public:
-    LLWebRTCLogSink(LLWebRTCLogCallback* callback) :
-    mCallback(callback)
-    {
-    }
+    LLWebRTCLogSink(LLWebRTCLogCallback* callback) : mCallback(callback) {}
 
     // Destructor: close the log file
-    ~LLWebRTCLogSink() override
-    {
-    }
+    ~LLWebRTCLogSink() override {}
 
-    void OnLogMessage(const std::string& msg,
-                      rtc::LoggingSeverity severity) override
+    void OnLogMessage(const std::string& msg, webrtc::LoggingSeverity severity) override
     {
         if (mCallback)
         {
-            switch(severity)
+            switch (severity)
             {
-                case rtc::LS_VERBOSE:
+                case webrtc::LS_VERBOSE:
                     mCallback->LogMessage(LLWebRTCLogCallback::LOG_LEVEL_VERBOSE, msg);
                     break;
-                case rtc::LS_INFO:
+                case webrtc::LS_INFO:
                     mCallback->LogMessage(LLWebRTCLogCallback::LOG_LEVEL_VERBOSE, msg);
                     break;
-                case rtc::LS_WARNING:
+                case webrtc::LS_WARNING:
                     mCallback->LogMessage(LLWebRTCLogCallback::LOG_LEVEL_VERBOSE, msg);
                     break;
-                case rtc::LS_ERROR:
+                case webrtc::LS_ERROR:
                     mCallback->LogMessage(LLWebRTCLogCallback::LOG_LEVEL_VERBOSE, msg);
                     break;
                 default:
@@ -118,73 +113,307 @@ private:
     LLWebRTCLogCallback* mCallback;
 };
 
-// Implements a class allowing capture of audio data
-// to determine audio level of the microphone.
-class LLAudioDeviceObserver : public webrtc::AudioDeviceDataObserver
+// -----------------------------------------------------------------------------
+// A proxy transport that forwards capture data to two AudioTransport sinks:
+//  - the "engine" (libwebrtc's VoiceEngine)
+//  - the "user" (your app's listener)
+//
+// Playout (NeedMorePlayData) goes only to the engine by default to avoid
+// double-writing into the output buffer. See notes below if you want a tap.
+// -----------------------------------------------------------------------------
+class LLWebRTCAudioTransport : public webrtc::AudioTransport
 {
-  public:
-    LLAudioDeviceObserver();
-
-    // Retrieve the RMS audio loudness
-    float getMicrophoneEnergy();
-
-    // Data retrieved from the caputure device is
-    // passed in here for processing.
-    void OnCaptureData(const void    *audio_samples,
-                       const size_t   num_samples,
-                       const size_t   bytes_per_sample,
-                       const size_t   num_channels,
-                       const uint32_t samples_per_sec) override;
-
-    // This is for data destined for the render device.
-    // not currently used.
-    void OnRenderData(const void    *audio_samples,
-                      const size_t   num_samples,
-                      const size_t   bytes_per_sample,
-                      const size_t   num_channels,
-                      const uint32_t samples_per_sec) override;
+public:
+    LLWebRTCAudioTransport();
+
+    void SetEngineTransport(webrtc::AudioTransport* t);
+
+    // -------- Capture path: fan out to both sinks --------
+    int32_t RecordedDataIsAvailable(const void* audio_data,
+                                    size_t      number_of_samples,
+                                    size_t      bytes_per_sample,
+                                    size_t      number_of_channels,
+                                    uint32_t    samples_per_sec,
+                                    uint32_t    total_delay_ms,
+                                    int32_t     clock_drift,
+                                    uint32_t    current_mic_level,
+                                    bool        key_pressed,
+                                    uint32_t&   new_mic_level) override;
+
+    // -------- Playout path: delegate to engine only --------
+    int32_t NeedMorePlayData(size_t   number_of_samples,
+                             size_t   bytes_per_sample,
+                             size_t   number_of_channels,
+                             uint32_t samples_per_sec,
+                             void*    audio_data,
+                             size_t&  number_of_samples_out,
+                             int64_t* elapsed_time_ms,
+                             int64_t* ntp_time_ms) override;
+
+    // Method to pull mixed render audio data from all active VoE channels.
+    // The data will not be passed as reference for audio processing internally.
+    void PullRenderData(int      bits_per_sample,
+                        int      sample_rate,
+                        size_t   number_of_channels,
+                        size_t   number_of_frames,
+                        void*    audio_data,
+                        int64_t* elapsed_time_ms,
+                        int64_t* ntp_time_ms) override;
+
+    float GetMicrophoneEnergy() { return mMicrophoneEnergy.load(std::memory_order_relaxed); }
+    void  SetGain(float gain) { mGain.store(gain, std::memory_order_relaxed); }
+
+private:
+    std::atomic<webrtc::AudioTransport*> engine_{ nullptr };
+    static const int                     NUM_PACKETS_TO_FILTER = 30; // 300 ms of smoothing (30 frames)
+    float                                mSumVector[NUM_PACKETS_TO_FILTER];
+    std::atomic<float>                   mMicrophoneEnergy;
+    std::atomic<float>                   mGain{ 0.0f };
 
-  protected:
-    static const int NUM_PACKETS_TO_FILTER = 30;  // 300 ms of smoothing (30 frames)
-    float mSumVector[NUM_PACKETS_TO_FILTER];
-    float mMicrophoneEnergy;
 };
 
+
+// -----------------------------------------------------------------------------
+// LLWebRTCAudioDeviceModule
+// - Wraps a real ADM to provide microphone energy for tuning
+// -----------------------------------------------------------------------------
+class LLWebRTCAudioDeviceModule : public webrtc::AudioDeviceModule
+{
+public:
+    explicit LLWebRTCAudioDeviceModule(webrtc::scoped_refptr<webrtc::AudioDeviceModule> inner) : inner_(std::move(inner)), tuning_(false)
+    {
+        RTC_CHECK(inner_);
+    }
+
+    // ----- AudioDeviceModule interface: we mostly forward to |inner_| -----
+    int32_t ActiveAudioLayer(AudioLayer* audioLayer) const override { return inner_->ActiveAudioLayer(audioLayer); }
+
+    int32_t RegisterAudioCallback(webrtc::AudioTransport* engine_transport) override
+    {
+        // The engine registers its transport here. We put our audio transport between engine and ADM.
+        audio_transport_.SetEngineTransport(engine_transport);
+        // Register our proxy with the real ADM.
+        return inner_->RegisterAudioCallback(&audio_transport_);
+    }
+
+    int32_t Init() override { return inner_->Init(); }
+    int32_t Terminate() override { return inner_->Terminate(); }
+    bool    Initialized() const override { return inner_->Initialized(); }
+
+    // --- Device enumeration/selection (forward) ---
+    int16_t PlayoutDevices() override { return inner_->PlayoutDevices(); }
+    int16_t RecordingDevices() override { return inner_->RecordingDevices(); }
+    int32_t PlayoutDeviceName(uint16_t index, char name[webrtc::kAdmMaxDeviceNameSize], char guid[webrtc::kAdmMaxGuidSize]) override
+    {
+        return inner_->PlayoutDeviceName(index, name, guid);
+    }
+    int32_t RecordingDeviceName(uint16_t index, char name[webrtc::kAdmMaxDeviceNameSize], char guid[webrtc::kAdmMaxGuidSize]) override
+    {
+        return inner_->RecordingDeviceName(index, name, guid);
+    }
+    int32_t SetPlayoutDevice(uint16_t index) override { return inner_->SetPlayoutDevice(index); }
+    int32_t SetRecordingDevice(uint16_t index) override { return inner_->SetRecordingDevice(index); }
+
+    // Windows default/communications selectors, if your branch exposes them:
+    int32_t SetPlayoutDevice(WindowsDeviceType type) override { return inner_->SetPlayoutDevice(type); }
+    int32_t SetRecordingDevice(WindowsDeviceType type) override { return inner_->SetRecordingDevice(type); }
+
+    // --- Init/start/stop (forward) ---
+    int32_t InitPlayout() override { return inner_->InitPlayout(); }
+    bool    PlayoutIsInitialized() const override { return inner_->PlayoutIsInitialized(); }
+    int32_t StartPlayout() override {
+        if (tuning_) return 0;  // For tuning, don't allow playout
+        return inner_->StartPlayout();
+    }
+    int32_t StopPlayout() override { return inner_->StopPlayout(); }
+    bool    Playing() const override { return inner_->Playing(); }
+
+    int32_t InitRecording() override { return inner_->InitRecording(); }
+    bool    RecordingIsInitialized() const override { return inner_->RecordingIsInitialized(); }
+    int32_t StartRecording() override {
+        // ignore start recording as webrtc.lib will
+        // send one when streams first connect, resulting
+        // in an inadvertant 'recording' when mute is on.
+        // We take full control of StartRecording via
+        // ForceStartRecording below.
+        return 0;
+    }
+    int32_t StopRecording() override {
+        if (tuning_) return 0;  // if we're tuning, disregard the StopRecording we get from disabling the streams
+        return inner_->StopRecording();
+    }
+    int32_t ForceStartRecording() { return inner_->StartRecording(); }
+    int32_t ForceStopRecording() { return inner_->StopRecording(); }
+    bool    Recording() const override { return inner_->Recording(); }
+
+    // --- Stereo opts (forward if available on your branch) ---
+    int32_t SetStereoPlayout(bool enable) override { return inner_->SetStereoPlayout(enable); }
+    int32_t SetStereoRecording(bool enable) override { return inner_->SetStereoRecording(enable); }
+    int32_t PlayoutIsAvailable(bool* available) override { return inner_->PlayoutIsAvailable(available); }
+    int32_t RecordingIsAvailable(bool* available) override { return inner_->RecordingIsAvailable(available); }
+
+    // --- AGC/Volume/Mute/etc. (forward) ---
+    int32_t SetMicrophoneVolume(uint32_t volume) override { return inner_->SetMicrophoneVolume(volume); }
+    int32_t MicrophoneVolume(uint32_t* volume) const override { return inner_->MicrophoneVolume(volume); }
+
+    // --- Speaker/Microphone init (forward) ---
+    int32_t InitSpeaker() override { return inner_->InitSpeaker(); }
+    bool    SpeakerIsInitialized() const override { return inner_->SpeakerIsInitialized(); }
+    int32_t InitMicrophone() override { return inner_->InitMicrophone(); }
+    bool    MicrophoneIsInitialized() const override { return inner_->MicrophoneIsInitialized(); }
+
+    // --- Speaker Volume (forward) ---
+    int32_t SpeakerVolumeIsAvailable(bool* available) override { return inner_->SpeakerVolumeIsAvailable(available); }
+    int32_t SetSpeakerVolume(uint32_t volume) override { return inner_->SetSpeakerVolume(volume); }
+    int32_t SpeakerVolume(uint32_t* volume) const override { return inner_->SpeakerVolume(volume); }
+    int32_t MaxSpeakerVolume(uint32_t* maxVolume) const override { return inner_->MaxSpeakerVolume(maxVolume); }
+    int32_t MinSpeakerVolume(uint32_t* minVolume) const override { return inner_->MinSpeakerVolume(minVolume); }
+
+    // --- Microphone Volume (forward) ---
+    int32_t MicrophoneVolumeIsAvailable(bool* available) override { return inner_->MicrophoneVolumeIsAvailable(available); }
+    int32_t MaxMicrophoneVolume(uint32_t* maxVolume) const override { return inner_->MaxMicrophoneVolume(maxVolume); }
+    int32_t MinMicrophoneVolume(uint32_t* minVolume) const override { return inner_->MinMicrophoneVolume(minVolume); }
+
+    // --- Speaker Mute (forward) ---
+    int32_t SpeakerMuteIsAvailable(bool* available) override { return inner_->SpeakerMuteIsAvailable(available); }
+    int32_t SetSpeakerMute(bool enable) override { return inner_->SetSpeakerMute(enable); }
+    int32_t SpeakerMute(bool* enabled) const override { return inner_->SpeakerMute(enabled); }
+
+    // --- Microphone Mute (forward) ---
+    int32_t MicrophoneMuteIsAvailable(bool* available) override { return inner_->MicrophoneMuteIsAvailable(available); }
+    int32_t SetMicrophoneMute(bool enable) override { return inner_->SetMicrophoneMute(enable); }
+    int32_t MicrophoneMute(bool* enabled) const override { return inner_->MicrophoneMute(enabled); }
+
+    // --- Stereo Support (forward) ---
+    int32_t StereoPlayoutIsAvailable(bool* available) const override { return inner_->StereoPlayoutIsAvailable(available); }
+    int32_t StereoPlayout(bool* enabled) const override { return inner_->StereoPlayout(enabled); }
+    int32_t StereoRecordingIsAvailable(bool* available) const override { return inner_->StereoRecordingIsAvailable(available); }
+    int32_t StereoRecording(bool* enabled) const override { return inner_->StereoRecording(enabled); }
+
+    // --- Delay/Timing (forward) ---
+    int32_t PlayoutDelay(uint16_t* delayMS) const override { return inner_->PlayoutDelay(delayMS); }
+
+    // --- Built-in Audio Processing (forward) ---
+    bool    BuiltInAECIsAvailable() const override { return inner_->BuiltInAECIsAvailable(); }
+    bool    BuiltInAGCIsAvailable() const override { return inner_->BuiltInAGCIsAvailable(); }
+    bool    BuiltInNSIsAvailable() const override { return inner_->BuiltInNSIsAvailable(); }
+    int32_t EnableBuiltInAEC(bool enable) override { return inner_->EnableBuiltInAEC(enable); }
+    int32_t EnableBuiltInAGC(bool enable) override { return inner_->EnableBuiltInAGC(enable); }
+    int32_t EnableBuiltInNS(bool enable) override { return inner_->EnableBuiltInNS(enable); }
+
+    // --- Additional AudioDeviceModule methods (forward) ---
+    int32_t GetPlayoutUnderrunCount() const override { return inner_->GetPlayoutUnderrunCount(); }
+
+    // Used to generate RTC stats. If not implemented, RTCAudioPlayoutStats will
+    // not be present in the stats.
+    std::optional<Stats> GetStats() const override { return inner_->GetStats(); }
+
+// Only supported on iOS.
+#if defined(WEBRTC_IOS)
+    virtual int GetPlayoutAudioParameters(AudioParameters* params) const override { return inner_->GetPlayoutAudioParameters(params); }
+    virtual int GetRecordAudioParameters(AudioParameters* params) override { return inner_->GetRecordAudioParameters(params); }
+#endif // WEBRTC_IOS
+
+    virtual int32_t GetPlayoutDevice() const override { return inner_->GetPlayoutDevice(); }
+    virtual int32_t GetRecordingDevice() const override { return inner_->GetRecordingDevice(); }
+    virtual int32_t SetObserver(webrtc::AudioDeviceObserver* observer) override { return inner_->SetObserver(observer); }
+
+    // tuning microphone energy calculations
+    float GetMicrophoneEnergy() { return audio_transport_.GetMicrophoneEnergy(); }
+    void SetTuningMicGain(float gain) { audio_transport_.SetGain(gain); }
+    void  SetTuning(bool tuning, bool mute)
+    {
+        tuning_ = tuning;
+        if (tuning)
+        {
+            inner_->InitRecording();
+            inner_->StartRecording();
+            inner_->StopPlayout();
+        }
+        else
+        {
+            if (mute)
+            {
+                inner_->StopRecording();
+            }
+            else
+            {
+                inner_->InitRecording();
+                inner_->StartRecording();
+            }
+            inner_->StartPlayout();
+        }
+    }
+
+protected:
+    ~LLWebRTCAudioDeviceModule() override = default;
+
+private:
+    webrtc::scoped_refptr<webrtc::AudioDeviceModule> inner_;
+    LLWebRTCAudioTransport                        audio_transport_;
+
+    bool tuning_;
+};
+
+class LLCustomProcessorState
+{
+
+public:
+    float getMicrophoneEnergy() { return mMicrophoneEnergy.load(std::memory_order_relaxed); }
+    void setMicrophoneEnergy(float energy) { mMicrophoneEnergy.store(energy, std::memory_order_relaxed); }
+
+    void setGain(float gain)
+    {
+        mGain.store(gain, std::memory_order_relaxed);
+        mDirty.store(true, std::memory_order_relaxed);
+    }
+
+    float getGain() { return mGain.load(std::memory_order_relaxed); }
+
+    bool getDirty() { return mDirty.exchange(false, std::memory_order_relaxed); }
+
+ protected:
+    std::atomic<bool>  mDirty{ true };
+    std::atomic<float> mMicrophoneEnergy{ 0.0f };
+    std::atomic<float> mGain{ 0.0f };
+};
+
+using LLCustomProcessorStatePtr = std::shared_ptr<LLCustomProcessorState>;
+
 // Used to process/retrieve audio levels after
 // all of the processing (AGC, AEC, etc.) for display in-world to the user.
 class LLCustomProcessor : public webrtc::CustomProcessing
 {
-  public:
-    LLCustomProcessor();
+public:
+    LLCustomProcessor(LLCustomProcessorStatePtr state);
     ~LLCustomProcessor() override {}
 
     // (Re-) Initializes the submodule.
     void Initialize(int sample_rate_hz, int num_channels) override;
 
     // Analyzes the given capture or render signal.
-    void Process(webrtc::AudioBuffer *audio) override;
+    void Process(webrtc::AudioBuffer* audio) override;
 
     // Returns a string representation of the module state.
     std::string ToString() const override { return ""; }
 
-    float getMicrophoneEnergy() { return mMicrophoneEnergy; }
-
-    void setGain(float gain) { mGain = gain; }
-
-  protected:
-    static const int NUM_PACKETS_TO_FILTER = 30;  // 300 ms of smoothing
-    int              mSampleRateHz;
-    int              mNumChannels;
+protected:
+    static const int NUM_PACKETS_TO_FILTER = 30; // 300 ms of smoothing
+    int              mSampleRateHz{ 48000 };
+    int              mNumChannels{ 2 };
+    int              mRampFrames{ 2 };
+    float            mCurrentGain{ 0.0f };
+    float            mGainStep{ 0.0f };
 
     float mSumVector[NUM_PACKETS_TO_FILTER];
-    float mMicrophoneEnergy;
-    float mGain;
+    friend LLCustomProcessorState;
+    LLCustomProcessorStatePtr mState;
 };
 
 
 // Primary singleton implementation for interfacing
 // with the native webrtc library.
-class LLWebRTCImpl : public LLWebRTCDeviceInterface, public webrtc::AudioDeviceSink
+class LLWebRTCImpl : public LLWebRTCDeviceInterface, public webrtc::AudioDeviceObserver
 {
   public:
     LLWebRTCImpl(LLWebRTCLogCallback* logCallback);
@@ -214,10 +443,15 @@ class LLWebRTCImpl : public LLWebRTCDeviceInterface, public webrtc::AudioDeviceS
     float getTuningAudioLevel() override;
     float getPeerConnectionAudioLevel() override;
 
-    void setPeerConnectionGain(float gain) override;
+    void setMicGain(float gain) override;
+    void setTuningMicGain(float gain) override;
+
+    void setMute(bool mute, int delay_ms = 20) override;
+
+    void intSetMute(bool mute, int delay_ms = 20);
 
     //
-    // AudioDeviceSink
+    // AudioDeviceObserver
     //
     void OnDevicesUpdated() override;
 
@@ -246,19 +480,19 @@ class LLWebRTCImpl : public LLWebRTCDeviceInterface, public webrtc::AudioDeviceS
         mNetworkThread->PostTask(std::move(task), location);
     }
 
-    void WorkerBlockingCall(rtc::FunctionView<void()> functor,
+    void WorkerBlockingCall(webrtc::FunctionView<void()> functor,
                   const webrtc::Location& location = webrtc::Location::Current())
     {
         mWorkerThread->BlockingCall(std::move(functor), location);
     }
 
-    void SignalingBlockingCall(rtc::FunctionView<void()> functor,
+    void SignalingBlockingCall(webrtc::FunctionView<void()> functor,
                   const webrtc::Location& location = webrtc::Location::Current())
     {
         mSignalingThread->BlockingCall(std::move(functor), location);
     }
 
-    void NetworkBlockingCall(rtc::FunctionView<void()> functor,
+    void NetworkBlockingCall(webrtc::FunctionView<void()> functor,
                   const webrtc::Location& location = webrtc::Location::Current())
     {
         mNetworkThread->BlockingCall(std::move(functor), location);
@@ -266,7 +500,7 @@ class LLWebRTCImpl : public LLWebRTCDeviceInterface, public webrtc::AudioDeviceS
 
     // Allows the LLWebRTCPeerConnectionImpl class to retrieve the
     // native webrtc PeerConnectionFactory.
-    rtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface> getPeerConnectionFactory()
+    webrtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface> getPeerConnectionFactory()
     {
         return mPeerConnectionFactory;
     }
@@ -275,49 +509,47 @@ class LLWebRTCImpl : public LLWebRTCDeviceInterface, public webrtc::AudioDeviceS
     LLWebRTCPeerConnectionInterface* newPeerConnection();
     void freePeerConnection(LLWebRTCPeerConnectionInterface* peer_connection);
 
-    // enables/disables capture via the capture device
-    void setRecording(bool recording);
-
-    void setPlayout(bool playing);
-
   protected:
+
+    void workerDeployDevices();
     LLWebRTCLogSink*                                           mLogSink;
 
     // The native webrtc threads
-    std::unique_ptr<rtc::Thread>                               mNetworkThread;
-    std::unique_ptr<rtc::Thread>                               mWorkerThread;
-    std::unique_ptr<rtc::Thread>                               mSignalingThread;
+    std::unique_ptr<webrtc::Thread>                            mNetworkThread;
+    std::unique_ptr<webrtc::Thread>                            mWorkerThread;
+    std::unique_ptr<webrtc::Thread>                            mSignalingThread;
 
     // The factory that allows creation of native webrtc PeerConnections.
-    rtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface> mPeerConnectionFactory;
+    webrtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface> mPeerConnectionFactory;
 
-    rtc::scoped_refptr<webrtc::AudioProcessing>                mAudioProcessingModule;
+    webrtc::scoped_refptr<webrtc::AudioProcessing>                mAudioProcessingModule;
 
     // more native webrtc stuff
-    std::unique_ptr<webrtc::TaskQueueFactory>                  mTaskQueueFactory;
+    std::unique_ptr<webrtc::TaskQueueFactory>                     mTaskQueueFactory;
 
 
     // Devices
     void updateDevices();
-    rtc::scoped_refptr<webrtc::AudioDeviceModule>              mTuningDeviceModule;
-    rtc::scoped_refptr<webrtc::AudioDeviceModule>              mPeerDeviceModule;
+    void deployDevices();
+    std::atomic<int>                                           mDevicesDeploying;
+    webrtc::scoped_refptr<LLWebRTCAudioDeviceModule>           mDeviceModule;
     std::vector<LLWebRTCDevicesObserver *>                     mVoiceDevicesObserverList;
 
     // accessors in native webrtc for devices aren't apparently implemented yet.
     bool                                                       mTuningMode;
-    int32_t                                                    mRecordingDevice;
+    std::string                                                mRecordingDevice;
     LLWebRTCVoiceDeviceList                                    mRecordingDeviceList;
 
-    int32_t                                                    mPlayoutDevice;
+    std::string                                                mPlayoutDevice;
     LLWebRTCVoiceDeviceList                                    mPlayoutDeviceList;
 
     bool                                                       mMute;
+    float                                                      mGain;
 
-    LLAudioDeviceObserver *                                    mTuningAudioDeviceObserver;
-    LLCustomProcessor *                                        mPeerCustomProcessor;
+    LLCustomProcessorStatePtr                                  mPeerCustomProcessor;
 
     // peer connections
-    std::vector<rtc::scoped_refptr<LLWebRTCPeerConnectionImpl>>     mPeerConnections;
+    std::vector<webrtc::scoped_refptr<LLWebRTCPeerConnectionImpl>> mPeerConnections;
 };
 
 
@@ -342,7 +574,7 @@ class LLWebRTCPeerConnectionImpl : public LLWebRTCPeerConnectionInterface,
     void terminate();
 
     virtual void AddRef() const override = 0;
-    virtual rtc::RefCountReleaseStatus Release() const override = 0;
+    virtual webrtc::RefCountReleaseStatus Release() const override = 0;
 
     //
     // LLWebRTCPeerConnection
@@ -373,10 +605,10 @@ class LLWebRTCPeerConnectionImpl : public LLWebRTCPeerConnectionInterface,
     //
 
     void OnSignalingChange(webrtc::PeerConnectionInterface::SignalingState new_state) override {}
-    void OnAddTrack(rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver,
-                    const std::vector<rtc::scoped_refptr<webrtc::MediaStreamInterface>> &streams) override;
-    void OnRemoveTrack(rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver) override;
-    void OnDataChannel(rtc::scoped_refptr<webrtc::DataChannelInterface> channel) override;
+    void OnAddTrack(webrtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver,
+                    const std::vector<webrtc::scoped_refptr<webrtc::MediaStreamInterface>> &streams) override;
+    void OnRemoveTrack(webrtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver) override;
+    void OnDataChannel(webrtc::scoped_refptr<webrtc::DataChannelInterface> channel) override;
     void OnRenegotiationNeeded() override {}
     void OnIceConnectionChange(webrtc::PeerConnectionInterface::IceConnectionState new_state) override {};
     void OnIceGatheringChange(webrtc::PeerConnectionInterface::IceGatheringState new_state) override;
@@ -415,7 +647,7 @@ class LLWebRTCPeerConnectionImpl : public LLWebRTCPeerConnectionInterface,
 
     LLWebRTCImpl * mWebRTCImpl;
 
-    rtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface> mPeerConnectionFactory;
+    webrtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface> mPeerConnectionFactory;
 
     typedef enum {
         MUTE_INITIAL,
@@ -429,12 +661,12 @@ class LLWebRTCPeerConnectionImpl : public LLWebRTCPeerConnectionInterface,
     std::vector<std::unique_ptr<webrtc::IceCandidateInterface>>  mCachedIceCandidates;
     bool mAnswerReceived;
 
-    rtc::scoped_refptr<webrtc::PeerConnectionInterface> mPeerConnection;
-    rtc::scoped_refptr<webrtc::MediaStreamInterface> mLocalStream;
+    webrtc::scoped_refptr<webrtc::PeerConnectionInterface> mPeerConnection;
+    webrtc::scoped_refptr<webrtc::MediaStreamInterface> mLocalStream;
 
     // data
     std::vector<LLWebRTCDataObserver *> mDataObserverList;
-    rtc::scoped_refptr<webrtc::DataChannelInterface> mDataChannel;
+    webrtc::scoped_refptr<webrtc::DataChannelInterface> mDataChannel;
 };
 
 }
diff --git a/indra/newview/llvoicewebrtc.cpp b/indra/newview/llvoicewebrtc.cpp
index 34f3e22182..b26a48fd5f 100644
--- a/indra/newview/llvoicewebrtc.cpp
+++ b/indra/newview/llvoicewebrtc.cpp
@@ -82,9 +82,15 @@ const std::string WEBRTC_VOICE_SERVER_TYPE = "webrtc";
 
 namespace {
 
-    const F32 MAX_AUDIO_DIST      = 50.0f;
-    const F32 VOLUME_SCALE_WEBRTC = 0.01f;
-    const F32 LEVEL_SCALE_WEBRTC  = 0.008f;
+    const F32      MAX_AUDIO_DIST           = 50.0f;
+    const F32      VOLUME_SCALE_WEBRTC      = 0.01f;
+    const F32      TUNING_LEVEL_SCALE       = 0.01f;
+    const F32      TUNING_LEVEL_START_POINT = 0.8f;
+    const F32      LEVEL_SCALE              = 0.005f;
+    const F32      LEVEL_START_POINT        = 0.18f;
+    const uint32_t SET_HIDDEN_RESTORE_DELAY_MS = 200;  // 200 ms to unmute again after hiding during teleport
+    const uint32_t MUTE_FADE_DELAY_MS       = 500;   // 20ms fade followed by 480ms silence gets rid of the click just after unmuting.
+                                                     // This is because the buffers and processing is cleared by the silence.
 
     const F32 SPEAKING_AUDIO_LEVEL = 0.30;
 
@@ -201,7 +207,6 @@ bool LLWebRTCVoiceClient::sShuttingDown = false;
 
 LLWebRTCVoiceClient::LLWebRTCVoiceClient() :
     mHidden(false),
-    mTuningMode(false),
     mTuningMicGain(0.0),
     mTuningSpeakerVolume(50),  // Set to 50 so the user can hear themselves when he sets his mic volume
     mDevicesListUpdated(false),
@@ -348,25 +353,45 @@ void LLWebRTCVoiceClient::updateSettings()
         static LLCachedControl<std::string> sOutputDevice(gSavedSettings, "VoiceOutputAudioDevice");
         setRenderDevice(sOutputDevice);
 
-        LL_INFOS("Voice") << "Input device: " << std::quoted(sInputDevice()) << ", output device: " << std::quoted(sOutputDevice()) << LL_ENDL;
+        LL_INFOS("Voice") << "Input device: " << std::quoted(sInputDevice()) << ", output device: " << std::quoted(sOutputDevice())
+                            << LL_ENDL;
 
         static LLCachedControl<F32> sMicLevel(gSavedSettings, "AudioLevelMic");
         setMicGain(sMicLevel);
 
         llwebrtc::LLWebRTCDeviceInterface::AudioConfig config;
 
+        bool audioConfigChanged = false;
+
         static LLCachedControl<bool> sEchoCancellation(gSavedSettings, "VoiceEchoCancellation", true);
-        config.mEchoCancellation = sEchoCancellation;
+        if (sEchoCancellation != config.mEchoCancellation)
+        {
+            config.mEchoCancellation = sEchoCancellation;
+            audioConfigChanged       = true;
+        }
 
         static LLCachedControl<bool> sAGC(gSavedSettings, "VoiceAutomaticGainControl", true);
-        config.mAGC = sAGC;
+        if (sAGC != config.mAGC)
+        {
+            config.mAGC        = sAGC;
+            audioConfigChanged = true;
+        }
 
-        static LLCachedControl<U32> sNoiseSuppressionLevel(gSavedSettings,
+        static LLCachedControl<U32> sNoiseSuppressionLevel(
+            gSavedSettings,
             "VoiceNoiseSuppressionLevel",
             llwebrtc::LLWebRTCDeviceInterface::AudioConfig::ENoiseSuppressionLevel::NOISE_SUPPRESSION_LEVEL_VERY_HIGH);
-        config.mNoiseSuppressionLevel = (llwebrtc::LLWebRTCDeviceInterface::AudioConfig::ENoiseSuppressionLevel)(U32)sNoiseSuppressionLevel;
-
-        mWebRTCDeviceInterface->setAudioConfig(config);
+        auto noiseSuppressionLevel =
+            (llwebrtc::LLWebRTCDeviceInterface::AudioConfig::ENoiseSuppressionLevel)(U32)sNoiseSuppressionLevel;
+        if (noiseSuppressionLevel != config.mNoiseSuppressionLevel)
+        {
+            config.mNoiseSuppressionLevel = noiseSuppressionLevel;
+            audioConfigChanged            = true;
+        }
+        if (audioConfigChanged)
+        {
+            mWebRTCDeviceInterface->setAudioConfig(config);
+        }
     }
 }
 
@@ -695,21 +720,38 @@ void LLWebRTCVoiceClient::OnDevicesChangedImpl(const llwebrtc::LLWebRTCVoiceDevi
     std::string outputDevice = gSavedSettings.getString("VoiceOutputAudioDevice");
 
     LL_DEBUGS("Voice") << "Setting devices to-input: '" << inputDevice << "' output: '" << outputDevice << "'" << LL_ENDL;
-    clearRenderDevices();
-    for (auto &device : render_devices)
+
+    // only set the render device if the device list has changed.
+    if (mRenderDevices.size() != render_devices.size() || !std::equal(mRenderDevices.begin(),
+                    mRenderDevices.end(),
+                    render_devices.begin(),
+                    [](const LLVoiceDevice& a, const llwebrtc::LLWebRTCVoiceDevice& b) {
+            return a.display_name == b.mDisplayName && a.full_name == b.mID; }))
     {
-        addRenderDevice(LLVoiceDevice(device.mDisplayName, device.mID));
+        clearRenderDevices();
+        for (auto& device : render_devices)
+        {
+            addRenderDevice(LLVoiceDevice(device.mDisplayName, device.mID));
+        }
+        setRenderDevice(outputDevice);
     }
-    setRenderDevice(outputDevice);
 
-    clearCaptureDevices();
-    for (auto &device : capture_devices)
+    // only set the capture device if the device list has changed.
+    if (mCaptureDevices.size() != capture_devices.size() ||!std::equal(mCaptureDevices.begin(),
+                    mCaptureDevices.end(),
+                    capture_devices.begin(),
+                    [](const LLVoiceDevice& a, const llwebrtc::LLWebRTCVoiceDevice& b)
+                    { return a.display_name == b.mDisplayName && a.full_name == b.mID; }))
     {
-        LL_DEBUGS("Voice") << "Checking capture device:'" << device.mID << "'" << LL_ENDL;
+        clearCaptureDevices();
+        for (auto& device : capture_devices)
+        {
+            LL_DEBUGS("Voice") << "Checking capture device:'" << device.mID << "'" << LL_ENDL;
 
-        addCaptureDevice(LLVoiceDevice(device.mDisplayName, device.mID));
+            addCaptureDevice(LLVoiceDevice(device.mDisplayName, device.mID));
+        }
+        setCaptureDevice(inputDevice);
     }
-    setCaptureDevice(inputDevice);
 
     setDevicesListUpdated(true);
 }
@@ -762,7 +804,14 @@ bool LLWebRTCVoiceClient::inTuningMode()
 
 void LLWebRTCVoiceClient::tuningSetMicVolume(float volume)
 {
-    mTuningMicGain      = volume;
+    if (volume != mTuningMicGain)
+    {
+        mTuningMicGain = volume;
+        if (mWebRTCDeviceInterface)
+        {
+            mWebRTCDeviceInterface->setTuningMicGain(volume);
+        }
+    }
 }
 
 void LLWebRTCVoiceClient::tuningSetSpeakerVolume(float volume)
@@ -774,21 +823,10 @@ void LLWebRTCVoiceClient::tuningSetSpeakerVolume(float volume)
     }
 }
 
-float LLWebRTCVoiceClient::getAudioLevel()
-{
-    if (mIsInTuningMode)
-    {
-        return (1.0f - mWebRTCDeviceInterface->getTuningAudioLevel() * LEVEL_SCALE_WEBRTC) * mTuningMicGain / 2.1f;
-    }
-    else
-    {
-        return (1.0f - mWebRTCDeviceInterface->getPeerConnectionAudioLevel() * LEVEL_SCALE_WEBRTC) * mMicGain / 2.1f;
-    }
-}
-
 float LLWebRTCVoiceClient::tuningGetEnergy(void)
 {
-    return getAudioLevel();
+    float rms = mWebRTCDeviceInterface->getTuningAudioLevel();
+    return TUNING_LEVEL_START_POINT - TUNING_LEVEL_SCALE * rms;
 }
 
 bool LLWebRTCVoiceClient::deviceSettingsAvailable()
@@ -824,6 +862,11 @@ void LLWebRTCVoiceClient::setHidden(bool hidden)
 
     if (inSpatialChannel())
     {
+        if (mWebRTCDeviceInterface)
+        {
+            mWebRTCDeviceInterface->setMute(mHidden || mMuteMic,
+                                            mHidden ? 0 : SET_HIDDEN_RESTORE_DELAY_MS); // delay 200ms so as to not pile up mutes/unmutes.
+        }
         if (mHidden)
         {
             // get out of the channel entirely
@@ -990,7 +1033,6 @@ void LLWebRTCVoiceClient::updatePosition(void)
         {
             if (participant->mRegion != region->getRegionID()) {
                 participant->mRegion = region->getRegionID();
-                setMuteMic(mMuteMic);
             }
         }
     }
@@ -1115,13 +1157,14 @@ void LLWebRTCVoiceClient::sendPositionUpdate(bool force)
 // Update our own volume on our participant, so it'll show up
 // in the UI.  This is done on all sessions, so switching
 // sessions retains consistent volume levels.
-void LLWebRTCVoiceClient::updateOwnVolume() {
-    F32 audio_level = 0.0;
-    if (!mMuteMic && !mTuningMode)
+void LLWebRTCVoiceClient::updateOwnVolume()
+{
+    F32 audio_level = 0.0f;
+    if (!mMuteMic)
     {
-        audio_level = getAudioLevel();
+        float rms = mWebRTCDeviceInterface->getPeerConnectionAudioLevel();
+        audio_level = LEVEL_START_POINT - LEVEL_SCALE * rms;
     }
-
     sessionState::for_each(boost::bind(predUpdateOwnVolume, _1, audio_level));
 }
 
@@ -1518,6 +1561,17 @@ void LLWebRTCVoiceClient::setMuteMic(bool muted)
     }
 
     mMuteMic = muted;
+
+    if (mIsInTuningMode)
+    {
+        return;
+    }
+
+    if (mWebRTCDeviceInterface)
+    {
+        mWebRTCDeviceInterface->setMute(muted, muted ? MUTE_FADE_DELAY_MS : 0);  // delay for 40ms on mute to allow buffers to empty
+    }
+
     // when you're hidden, your mic is always muted.
     if (!mHidden)
     {
@@ -1556,7 +1610,10 @@ void LLWebRTCVoiceClient::setMicGain(F32 gain)
     if (gain != mMicGain)
     {
         mMicGain = gain;
-        mWebRTCDeviceInterface->setPeerConnectionGain(gain);
+        if (mWebRTCDeviceInterface)
+        {
+            mWebRTCDeviceInterface->setMicGain(gain);
+        }
     }
 }
 
diff --git a/indra/newview/llvoicewebrtc.h b/indra/newview/llvoicewebrtc.h
index 71347f206a..722d81fdc2 100644
--- a/indra/newview/llvoicewebrtc.h
+++ b/indra/newview/llvoicewebrtc.h
@@ -444,10 +444,6 @@ public:
 
 private:
 
-    // helper function to retrieve the audio level
-    // Used in multiple places.
-    float getAudioLevel();
-
     // Coroutine support methods
     //---
     void voiceConnectionCoro();
@@ -458,7 +454,6 @@ private:
 
     LL::WorkQueue::weak_t mMainQueue;
 
-    bool mTuningMode;
     F32 mTuningMicGain;
     int mTuningSpeakerVolume;
     bool mDevicesListUpdated;            // set to true when the device list has been updated