diff --git a/audio/aidl/common/include/Utils.h b/audio/aidl/common/include/Utils.h
index dd7975d1be..d354859a87 100644
--- a/audio/aidl/common/include/Utils.h
+++ b/audio/aidl/common/include/Utils.h
@@ -29,6 +29,21 @@
 #include <aidl/android/media/audio/common/AudioMode.h>
 #include <aidl/android/media/audio/common/AudioOutputFlags.h>
 #include <aidl/android/media/audio/common/PcmType.h>
+#include <android/binder_auto_utils.h>
+
+namespace ndk {
+
+// This enables use of 'error/expected_utils' for ScopedAStatus.
+
+inline bool errorIsOk(const ScopedAStatus& s) {
+    return s.isOk();
+}
+
+inline std::string errorToString(const ScopedAStatus& s) {
+    return s.getDescription();
+}
+
+}  // namespace ndk
 
 namespace aidl::android::hardware::audio::common {
 
diff --git a/audio/aidl/default/Module.cpp b/audio/aidl/default/Module.cpp
index 6885a49d6b..6f89d4bc11 100644
--- a/audio/aidl/default/Module.cpp
+++ b/audio/aidl/default/Module.cpp
@@ -18,19 +18,18 @@
 #include <set>
 
 #define LOG_TAG "AHAL_Module"
-#include <android-base/logging.h>
-#include <android/binder_ibinder_platform.h>
-
 #include <Utils.h>
 #include <aidl/android/media/audio/common/AudioInputFlags.h>
 #include <aidl/android/media/audio/common/AudioOutputFlags.h>
+#include <android-base/logging.h>
+#include <android/binder_ibinder_platform.h>
+#include <error/expected_utils.h>
 
 #include "core-impl/Bluetooth.h"
 #include "core-impl/Module.h"
 #include "core-impl/ModuleUsb.h"
 #include "core-impl/SoundDose.h"
 #include "core-impl/StreamStub.h"
-#include "core-impl/StreamUsb.h"
 #include "core-impl/Telephony.h"
 #include "core-impl/utils.h"
 
@@ -119,30 +118,6 @@ std::shared_ptr<Module> Module::createInstance(Type type) {
     }
 }
 
-// static
-StreamIn::CreateInstance Module::getStreamInCreator(Type type) {
-    switch (type) {
-        case Type::USB:
-            return StreamInUsb::createInstance;
-        case Type::DEFAULT:
-        case Type::R_SUBMIX:
-        default:
-            return StreamInStub::createInstance;
-    }
-}
-
-// static
-StreamOut::CreateInstance Module::getStreamOutCreator(Type type) {
-    switch (type) {
-        case Type::USB:
-            return StreamOutUsb::createInstance;
-        case Type::DEFAULT:
-        case Type::R_SUBMIX:
-        default:
-            return StreamOutStub::createInstance;
-    }
-}
-
 std::ostream& operator<<(std::ostream& os, Module::Type t) {
     switch (t) {
         case Module::Type::DEFAULT:
@@ -207,7 +182,8 @@ ndk::ScopedAStatus Module::createStreamContext(
                 std::make_unique<StreamContext::CommandMQ>(1, true /*configureEventFlagWord*/),
                 std::make_unique<StreamContext::ReplyMQ>(1, true /*configureEventFlagWord*/),
                 portConfigIt->format.value(), portConfigIt->channelMask.value(),
-                portConfigIt->sampleRate.value().value,
+                portConfigIt->sampleRate.value().value, flags,
+                portConfigIt->ext.get<AudioPortExt::mix>().handle,
                 std::make_unique<StreamContext::DataMQ>(frameSize * in_bufferSizeFrames),
                 asyncCallback, outEventCallback, params);
         if (temp.isValid()) {
@@ -339,30 +315,61 @@ void Module::registerPatch(const AudioPatch& patch) {
     do_insert(patch.sinkPortConfigIds);
 }
 
-void Module::updateStreamsConnectedState(const AudioPatch& oldPatch, const AudioPatch& newPatch) {
+ndk::ScopedAStatus Module::updateStreamsConnectedState(const AudioPatch& oldPatch,
+                                                       const AudioPatch& newPatch) {
     // Streams from the old patch need to be disconnected, streams from the new
     // patch need to be connected. If the stream belongs to both patches, no need
     // to update it.
-    std::set<int32_t> idsToDisconnect, idsToConnect;
+    auto maybeFailure = ndk::ScopedAStatus::ok();
+    std::set<int32_t> idsToDisconnect, idsToConnect, idsToDisconnectOnFailure;
     idsToDisconnect.insert(oldPatch.sourcePortConfigIds.begin(),
                            oldPatch.sourcePortConfigIds.end());
     idsToDisconnect.insert(oldPatch.sinkPortConfigIds.begin(), oldPatch.sinkPortConfigIds.end());
     idsToConnect.insert(newPatch.sourcePortConfigIds.begin(), newPatch.sourcePortConfigIds.end());
     idsToConnect.insert(newPatch.sinkPortConfigIds.begin(), newPatch.sinkPortConfigIds.end());
     std::for_each(idsToDisconnect.begin(), idsToDisconnect.end(), [&](const auto& portConfigId) {
-        if (idsToConnect.count(portConfigId) == 0) {
-            LOG(DEBUG) << "The stream on port config id " << portConfigId << " is not connected";
-            mStreams.setStreamIsConnected(portConfigId, {});
+        if (idsToConnect.count(portConfigId) == 0 && mStreams.count(portConfigId) != 0) {
+            if (auto status = mStreams.setStreamConnectedDevices(portConfigId, {}); status.isOk()) {
+                LOG(DEBUG) << "updateStreamsConnectedState: The stream on port config id "
+                           << portConfigId << " has been disconnected";
+            } else {
+                // Disconnection is tricky to roll back, just register a failure.
+                maybeFailure = std::move(status);
+            }
         }
     });
+    if (!maybeFailure.isOk()) return maybeFailure;
     std::for_each(idsToConnect.begin(), idsToConnect.end(), [&](const auto& portConfigId) {
-        if (idsToDisconnect.count(portConfigId) == 0) {
+        if (idsToDisconnect.count(portConfigId) == 0 && mStreams.count(portConfigId) != 0) {
             const auto connectedDevices = findConnectedDevices(portConfigId);
-            LOG(DEBUG) << "The stream on port config id " << portConfigId
-                       << " is connected to: " << ::android::internal::ToString(connectedDevices);
-            mStreams.setStreamIsConnected(portConfigId, connectedDevices);
+            if (connectedDevices.empty()) {
+                // This is important as workers use the vector size to derive the connection status.
+                LOG(FATAL) << "updateStreamsConnectedState: No connected devices found for port "
+                              "config id "
+                           << portConfigId;
+            }
+            if (auto status = mStreams.setStreamConnectedDevices(portConfigId, connectedDevices);
+                status.isOk()) {
+                LOG(DEBUG) << "updateStreamsConnectedState: The stream on port config id "
+                           << portConfigId << " has been connected to: "
+                           << ::android::internal::ToString(connectedDevices);
+            } else {
+                maybeFailure = std::move(status);
+                idsToDisconnectOnFailure.insert(portConfigId);
+            }
         }
     });
+    if (!maybeFailure.isOk()) {
+        LOG(WARNING) << __func__ << ": Due to a failure, disconnecting streams on port config ids "
+                     << ::android::internal::ToString(idsToDisconnectOnFailure);
+        std::for_each(idsToDisconnectOnFailure.begin(), idsToDisconnectOnFailure.end(),
+                      [&](const auto& portConfigId) {
+                          auto status = mStreams.setStreamConnectedDevices(portConfigId, {});
+                          (void)status.isOk();  // Can't do much about a failure here.
+                      });
+        return maybeFailure;
+    }
+    return ndk::ScopedAStatus::ok();
 }
 
 ndk::ScopedAStatus Module::setModuleDebug(
@@ -469,10 +476,7 @@ ndk::ScopedAStatus Module::connectExternalDevice(const AudioPort& in_templateIdA
     }
 
     if (!mDebug.simulateDeviceConnections) {
-        if (ndk::ScopedAStatus status = populateConnectedDevicePort(&connectedPort);
-            !status.isOk()) {
-            return status;
-        }
+        RETURN_STATUS_IF_ERROR(populateConnectedDevicePort(&connectedPort));
     } else {
         auto& connectedProfiles = getConfig().connectedProfiles;
         if (auto connectedProfilesIt = connectedProfiles.find(templateId);
@@ -647,34 +651,26 @@ ndk::ScopedAStatus Module::openInputStream(const OpenInputStreamArguments& in_ar
     LOG(DEBUG) << __func__ << ": port config id " << in_args.portConfigId << ", buffer size "
                << in_args.bufferSizeFrames << " frames";
     AudioPort* port = nullptr;
-    if (auto status = findPortIdForNewStream(in_args.portConfigId, &port); !status.isOk()) {
-        return status;
-    }
+    RETURN_STATUS_IF_ERROR(findPortIdForNewStream(in_args.portConfigId, &port));
     if (port->flags.getTag() != AudioIoFlags::Tag::input) {
         LOG(ERROR) << __func__ << ": port config id " << in_args.portConfigId
                    << " does not correspond to an input mix port";
         return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
     }
     StreamContext context;
-    if (auto status = createStreamContext(in_args.portConfigId, in_args.bufferSizeFrames, nullptr,
-                                          nullptr, &context);
-        !status.isOk()) {
-        return status;
-    }
+    RETURN_STATUS_IF_ERROR(createStreamContext(in_args.portConfigId, in_args.bufferSizeFrames,
+                                               nullptr, nullptr, &context));
     context.fillDescriptor(&_aidl_return->desc);
     std::shared_ptr<StreamIn> stream;
-    ndk::ScopedAStatus status = getStreamInCreator(mType)(in_args.sinkMetadata, std::move(context),
-                                                          mConfig->microphones, &stream);
-    if (!status.isOk()) {
-        return status;
-    }
+    RETURN_STATUS_IF_ERROR(createInputStream(in_args.sinkMetadata, std::move(context),
+                                             mConfig->microphones, &stream));
     StreamWrapper streamWrapper(stream);
+    if (auto patchIt = mPatches.find(in_args.portConfigId); patchIt != mPatches.end()) {
+        RETURN_STATUS_IF_ERROR(
+                streamWrapper.setConnectedDevices(findConnectedDevices(in_args.portConfigId)));
+    }
     AIBinder_setMinSchedulerPolicy(streamWrapper.getBinder().get(), SCHED_NORMAL,
                                    ANDROID_PRIORITY_AUDIO);
-    auto patchIt = mPatches.find(in_args.portConfigId);
-    if (patchIt != mPatches.end()) {
-        streamWrapper.setStreamIsConnected(findConnectedDevices(in_args.portConfigId));
-    }
     mStreams.insert(port->id, in_args.portConfigId, std::move(streamWrapper));
     _aidl_return->stream = std::move(stream);
     return ndk::ScopedAStatus::ok();
@@ -686,9 +682,7 @@ ndk::ScopedAStatus Module::openOutputStream(const OpenOutputStreamArguments& in_
                << (in_args.offloadInfo.has_value()) << ", buffer size " << in_args.bufferSizeFrames
                << " frames";
     AudioPort* port = nullptr;
-    if (auto status = findPortIdForNewStream(in_args.portConfigId, &port); !status.isOk()) {
-        return status;
-    }
+    RETURN_STATUS_IF_ERROR(findPortIdForNewStream(in_args.portConfigId, &port));
     if (port->flags.getTag() != AudioIoFlags::Tag::output) {
         LOG(ERROR) << __func__ << ": port config id " << in_args.portConfigId
                    << " does not correspond to an output mix port";
@@ -709,26 +703,20 @@ ndk::ScopedAStatus Module::openOutputStream(const OpenOutputStreamArguments& in_
         return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
     }
     StreamContext context;
-    if (auto status = createStreamContext(in_args.portConfigId, in_args.bufferSizeFrames,
-                                          isNonBlocking ? in_args.callback : nullptr,
-                                          in_args.eventCallback, &context);
-        !status.isOk()) {
-        return status;
-    }
+    RETURN_STATUS_IF_ERROR(createStreamContext(in_args.portConfigId, in_args.bufferSizeFrames,
+                                               isNonBlocking ? in_args.callback : nullptr,
+                                               in_args.eventCallback, &context));
     context.fillDescriptor(&_aidl_return->desc);
     std::shared_ptr<StreamOut> stream;
-    ndk::ScopedAStatus status = getStreamOutCreator(mType)(
-            in_args.sourceMetadata, std::move(context), in_args.offloadInfo, &stream);
-    if (!status.isOk()) {
-        return status;
-    }
+    RETURN_STATUS_IF_ERROR(createOutputStream(in_args.sourceMetadata, std::move(context),
+                                              in_args.offloadInfo, &stream));
     StreamWrapper streamWrapper(stream);
+    if (auto patchIt = mPatches.find(in_args.portConfigId); patchIt != mPatches.end()) {
+        RETURN_STATUS_IF_ERROR(
+                streamWrapper.setConnectedDevices(findConnectedDevices(in_args.portConfigId)));
+    }
     AIBinder_setMinSchedulerPolicy(streamWrapper.getBinder().get(), SCHED_NORMAL,
                                    ANDROID_PRIORITY_AUDIO);
-    auto patchIt = mPatches.find(in_args.portConfigId);
-    if (patchIt != mPatches.end()) {
-        streamWrapper.setStreamIsConnected(findConnectedDevices(in_args.portConfigId));
-    }
     mStreams.insert(port->id, in_args.portConfigId, std::move(streamWrapper));
     _aidl_return->stream = std::move(stream);
     return ndk::ScopedAStatus::ok();
@@ -796,10 +784,7 @@ ndk::ScopedAStatus Module::setAudioPatch(const AudioPatch& in_requested, AudioPa
             return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
         }
     }
-
-    if (auto status = checkAudioPatchEndpointsMatch(sources, sinks); !status.isOk()) {
-        return status;
-    }
+    RETURN_STATUS_IF_ERROR(checkAudioPatchEndpointsMatch(sources, sinks));
 
     auto& patches = getConfig().patches;
     auto existing = patches.end();
@@ -834,13 +819,20 @@ ndk::ScopedAStatus Module::setAudioPatch(const AudioPatch& in_requested, AudioPa
     if (existing == patches.end()) {
         _aidl_return->id = getConfig().nextPatchId++;
         patches.push_back(*_aidl_return);
-        existing = patches.begin() + (patches.size() - 1);
     } else {
         oldPatch = *existing;
-        *existing = *_aidl_return;
     }
-    registerPatch(*existing);
-    updateStreamsConnectedState(oldPatch, *_aidl_return);
+    patchesBackup = mPatches;
+    registerPatch(*_aidl_return);
+    if (auto status = updateStreamsConnectedState(oldPatch, *_aidl_return); !status.isOk()) {
+        mPatches = std::move(*patchesBackup);
+        if (existing == patches.end()) {
+            patches.pop_back();
+        } else {
+            *existing = oldPatch;
+        }
+        return status;
+    }
 
     LOG(DEBUG) << __func__ << ": " << (oldPatch.id == 0 ? "created" : "updated") << " patch "
                << _aidl_return->toString();
@@ -992,8 +984,12 @@ ndk::ScopedAStatus Module::resetAudioPatch(int32_t in_patchId) {
     auto& patches = getConfig().patches;
     auto patchIt = findById<AudioPatch>(patches, in_patchId);
     if (patchIt != patches.end()) {
+        auto patchesBackup = mPatches;
         cleanUpPatch(patchIt->id);
-        updateStreamsConnectedState(*patchIt, AudioPatch{});
+        if (auto status = updateStreamsConnectedState(*patchIt, AudioPatch{}); !status.isOk()) {
+            mPatches = std::move(patchesBackup);
+            return status;
+        }
         patches.erase(patchIt);
         LOG(DEBUG) << __func__ << ": erased patch " << in_patchId;
         return ndk::ScopedAStatus::ok();
@@ -1325,6 +1321,22 @@ bool Module::isMmapSupported() {
     return mIsMmapSupported.value();
 }
 
+ndk::ScopedAStatus Module::createInputStream(const SinkMetadata& sinkMetadata,
+                                             StreamContext&& context,
+                                             const std::vector<MicrophoneInfo>& microphones,
+                                             std::shared_ptr<StreamIn>* result) {
+    return createStreamInstance<StreamInStub>(result, sinkMetadata, std::move(context),
+                                              microphones);
+}
+
+ndk::ScopedAStatus Module::createOutputStream(const SourceMetadata& sourceMetadata,
+                                              StreamContext&& context,
+                                              const std::optional<AudioOffloadInfo>& offloadInfo,
+                                              std::shared_ptr<StreamOut>* result) {
+    return createStreamInstance<StreamOutStub>(result, sourceMetadata, std::move(context),
+                                               offloadInfo);
+}
+
 ndk::ScopedAStatus Module::populateConnectedDevicePort(AudioPort* audioPort __unused) {
     LOG(VERBOSE) << __func__ << ": do nothing and return ok";
     return ndk::ScopedAStatus::ok();
diff --git a/audio/aidl/default/Stream.cpp b/audio/aidl/default/Stream.cpp
index 77b06011c6..73f1293007 100644
--- a/audio/aidl/default/Stream.cpp
+++ b/audio/aidl/default/Stream.cpp
@@ -152,6 +152,7 @@ StreamInWorkerLogic::Status StreamInWorkerLogic::cycle() {
         case Tag::halReservedExit:
             if (const int32_t cookie = command.get<Tag::halReservedExit>();
                 cookie == mInternalCommandCookie) {
+                mDriver->shutdown();
                 setClosed();
                 // This is an internal command, no need to reply.
                 return Status::EXIT;
@@ -364,6 +365,7 @@ StreamOutWorkerLogic::Status StreamOutWorkerLogic::cycle() {
         case Tag::halReservedExit:
             if (const int32_t cookie = command.get<Tag::halReservedExit>();
                 cookie == mInternalCommandCookie) {
+                mDriver->shutdown();
                 setClosed();
                 // This is an internal command, no need to reply.
                 return Status::EXIT;
@@ -567,8 +569,7 @@ bool StreamOutWorkerLogic::write(size_t clientSize, StreamDescriptor::Reply* rep
     return !fatal;
 }
 
-template <class Metadata>
-StreamCommonImpl<Metadata>::~StreamCommonImpl() {
+StreamCommonImpl::~StreamCommonImpl() {
     if (!isClosed()) {
         LOG(ERROR) << __func__ << ": stream was not closed prior to destruction, resource leak";
         stopWorker();
@@ -576,19 +577,16 @@ StreamCommonImpl<Metadata>::~StreamCommonImpl() {
     }
 }
 
-template <class Metadata>
-void StreamCommonImpl<Metadata>::createStreamCommon(
+ndk::ScopedAStatus StreamCommonImpl::initInstance(
         const std::shared_ptr<StreamCommonInterface>& delegate) {
-    if (mCommon != nullptr) {
-        LOG(FATAL) << __func__ << ": attempting to create the common interface twice";
-    }
-    mCommon = ndk::SharedRefBase::make<StreamCommon>(delegate);
+    mCommon = ndk::SharedRefBase::make<StreamCommonDelegator>(delegate);
     mCommonBinder = mCommon->asBinder();
     AIBinder_setMinSchedulerPolicy(mCommonBinder.get(), SCHED_NORMAL, ANDROID_PRIORITY_AUDIO);
+    return mWorker->start() ? ndk::ScopedAStatus::ok()
+                            : ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
 }
 
-template <class Metadata>
-ndk::ScopedAStatus StreamCommonImpl<Metadata>::getStreamCommon(
+ndk::ScopedAStatus StreamCommonImpl::getStreamCommonCommon(
         std::shared_ptr<IStreamCommon>* _aidl_return) {
     if (mCommon == nullptr) {
         LOG(FATAL) << __func__ << ": the common interface was not created";
@@ -598,30 +596,26 @@ ndk::ScopedAStatus StreamCommonImpl<Metadata>::getStreamCommon(
     return ndk::ScopedAStatus::ok();
 }
 
-template <class Metadata>
-ndk::ScopedAStatus StreamCommonImpl<Metadata>::updateHwAvSyncId(int32_t in_hwAvSyncId) {
+ndk::ScopedAStatus StreamCommonImpl::updateHwAvSyncId(int32_t in_hwAvSyncId) {
     LOG(DEBUG) << __func__ << ": id " << in_hwAvSyncId;
     return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
 }
 
-template <class Metadata>
-ndk::ScopedAStatus StreamCommonImpl<Metadata>::getVendorParameters(
+ndk::ScopedAStatus StreamCommonImpl::getVendorParameters(
         const std::vector<std::string>& in_ids, std::vector<VendorParameter>* _aidl_return) {
     LOG(DEBUG) << __func__ << ": id count: " << in_ids.size();
     (void)_aidl_return;
     return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
 }
 
-template <class Metadata>
-ndk::ScopedAStatus StreamCommonImpl<Metadata>::setVendorParameters(
+ndk::ScopedAStatus StreamCommonImpl::setVendorParameters(
         const std::vector<VendorParameter>& in_parameters, bool in_async) {
     LOG(DEBUG) << __func__ << ": parameters count " << in_parameters.size()
                << ", async: " << in_async;
     return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
 }
 
-template <class Metadata>
-ndk::ScopedAStatus StreamCommonImpl<Metadata>::addEffect(
+ndk::ScopedAStatus StreamCommonImpl::addEffect(
         const std::shared_ptr<::aidl::android::hardware::audio::effect::IEffect>& in_effect) {
     if (in_effect == nullptr) {
         LOG(DEBUG) << __func__ << ": null effect";
@@ -631,8 +625,7 @@ ndk::ScopedAStatus StreamCommonImpl<Metadata>::addEffect(
     return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
 }
 
-template <class Metadata>
-ndk::ScopedAStatus StreamCommonImpl<Metadata>::removeEffect(
+ndk::ScopedAStatus StreamCommonImpl::removeEffect(
         const std::shared_ptr<::aidl::android::hardware::audio::effect::IEffect>& in_effect) {
     if (in_effect == nullptr) {
         LOG(DEBUG) << __func__ << ": null effect";
@@ -642,8 +635,7 @@ ndk::ScopedAStatus StreamCommonImpl<Metadata>::removeEffect(
     return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
 }
 
-template <class Metadata>
-ndk::ScopedAStatus StreamCommonImpl<Metadata>::close() {
+ndk::ScopedAStatus StreamCommonImpl::close() {
     LOG(DEBUG) << __func__;
     if (!isClosed()) {
         stopWorker();
@@ -659,8 +651,7 @@ ndk::ScopedAStatus StreamCommonImpl<Metadata>::close() {
     }
 }
 
-template <class Metadata>
-ndk::ScopedAStatus StreamCommonImpl<Metadata>::prepareToClose() {
+ndk::ScopedAStatus StreamCommonImpl::prepareToClose() {
     LOG(DEBUG) << __func__;
     if (!isClosed()) {
         return ndk::ScopedAStatus::ok();
@@ -669,8 +660,7 @@ ndk::ScopedAStatus StreamCommonImpl<Metadata>::prepareToClose() {
     return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
 }
 
-template <class Metadata>
-void StreamCommonImpl<Metadata>::stopWorker() {
+void StreamCommonImpl::stopWorker() {
     if (auto commandMQ = mContext.getCommandMQ(); commandMQ != nullptr) {
         LOG(DEBUG) << __func__ << ": asking the worker to exit...";
         auto cmd = StreamDescriptor::Command::make<StreamDescriptor::Command::Tag::halReservedExit>(
@@ -686,10 +676,12 @@ void StreamCommonImpl<Metadata>::stopWorker() {
     }
 }
 
-template <class Metadata>
-ndk::ScopedAStatus StreamCommonImpl<Metadata>::updateMetadata(const Metadata& metadata) {
+ndk::ScopedAStatus StreamCommonImpl::updateMetadataCommon(const Metadata& metadata) {
     LOG(DEBUG) << __func__;
     if (!isClosed()) {
+        if (metadata.index() != mMetadata.index()) {
+            LOG(FATAL) << __func__ << ": changing metadata variant is not allowed";
+        }
         mMetadata = metadata;
         return ndk::ScopedAStatus::ok();
     }
@@ -697,12 +689,10 @@ ndk::ScopedAStatus StreamCommonImpl<Metadata>::updateMetadata(const Metadata& me
     return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
 }
 
-// static
-ndk::ScopedAStatus StreamIn::initInstance(const std::shared_ptr<StreamIn>& stream) {
-    if (auto status = stream->init(); !status.isOk()) {
-        return status;
-    }
-    stream->createStreamCommon(stream);
+ndk::ScopedAStatus StreamCommonImpl::setConnectedDevices(
+        const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices) {
+    mWorker->setIsConnected(!devices.empty());
+    mConnectedDevices = devices;
     return ndk::ScopedAStatus::ok();
 }
 
@@ -716,12 +706,8 @@ static std::map<AudioDevice, std::string> transformMicrophones(
 }
 }  // namespace
 
-StreamIn::StreamIn(const SinkMetadata& sinkMetadata, StreamContext&& context,
-                   const DriverInterface::CreateInstance& createDriver,
-                   const StreamWorkerInterface::CreateInstance& createWorker,
-                   const std::vector<MicrophoneInfo>& microphones)
-    : StreamCommonImpl<SinkMetadata>(sinkMetadata, std::move(context), createDriver, createWorker),
-      mMicrophones(transformMicrophones(microphones)) {
+StreamIn::StreamIn(const std::vector<MicrophoneInfo>& microphones)
+    : mMicrophones(transformMicrophones(microphones)) {
     LOG(DEBUG) << __func__;
 }
 
@@ -729,9 +715,9 @@ ndk::ScopedAStatus StreamIn::getActiveMicrophones(
         std::vector<MicrophoneDynamicInfo>* _aidl_return) {
     std::vector<MicrophoneDynamicInfo> result;
     std::vector<MicrophoneDynamicInfo::ChannelMapping> channelMapping{
-            getChannelCount(mContext.getChannelLayout()),
+            getChannelCount(getContext().getChannelLayout()),
             MicrophoneDynamicInfo::ChannelMapping::DIRECT};
-    for (auto it = mConnectedDevices.begin(); it != mConnectedDevices.end(); ++it) {
+    for (auto it = getConnectedDevices().begin(); it != getConnectedDevices().end(); ++it) {
         if (auto micIt = mMicrophones.find(*it); micIt != mMicrophones.end()) {
             MicrophoneDynamicInfo dynMic;
             dynMic.id = micIt->second;
@@ -777,22 +763,8 @@ ndk::ScopedAStatus StreamIn::setHwGain(const std::vector<float>& in_channelGains
     return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
 }
 
-// static
-ndk::ScopedAStatus StreamOut::initInstance(const std::shared_ptr<StreamOut>& stream) {
-    if (auto status = stream->init(); !status.isOk()) {
-        return status;
-    }
-    stream->createStreamCommon(stream);
-    return ndk::ScopedAStatus::ok();
-}
-
-StreamOut::StreamOut(const SourceMetadata& sourceMetadata, StreamContext&& context,
-                     const DriverInterface::CreateInstance& createDriver,
-                     const StreamWorkerInterface::CreateInstance& createWorker,
-                     const std::optional<AudioOffloadInfo>& offloadInfo)
-    : StreamCommonImpl<SourceMetadata>(sourceMetadata, std::move(context), createDriver,
-                                       createWorker),
-      mOffloadInfo(offloadInfo) {
+StreamOut::StreamOut(const std::optional<AudioOffloadInfo>& offloadInfo)
+    : mOffloadInfo(offloadInfo) {
     LOG(DEBUG) << __func__;
 }
 
diff --git a/audio/aidl/default/StreamStub.cpp b/audio/aidl/default/StreamStub.cpp
index 2467320f0c..d88dfbc3c2 100644
--- a/audio/aidl/default/StreamStub.cpp
+++ b/audio/aidl/default/StreamStub.cpp
@@ -31,33 +31,34 @@ using aidl::android::media::audio::common::MicrophoneInfo;
 
 namespace aidl::android::hardware::audio::core {
 
-DriverStub::DriverStub(const StreamContext& context, bool isInput)
-    : mFrameSizeBytes(context.getFrameSize()),
+StreamStub::StreamStub(const Metadata& metadata, StreamContext&& context)
+    : StreamCommonImpl(metadata, std::move(context)),
+      mFrameSizeBytes(context.getFrameSize()),
       mSampleRate(context.getSampleRate()),
       mIsAsynchronous(!!context.getAsyncCallback()),
-      mIsInput(isInput) {}
+      mIsInput(isInput(metadata)) {}
 
-::android::status_t DriverStub::init() {
+::android::status_t StreamStub::init() {
     usleep(500);
     return ::android::OK;
 }
 
-::android::status_t DriverStub::drain(StreamDescriptor::DrainMode) {
+::android::status_t StreamStub::drain(StreamDescriptor::DrainMode) {
     usleep(500);
     return ::android::OK;
 }
 
-::android::status_t DriverStub::flush() {
+::android::status_t StreamStub::flush() {
     usleep(500);
     return ::android::OK;
 }
 
-::android::status_t DriverStub::pause() {
+::android::status_t StreamStub::pause() {
     usleep(500);
     return ::android::OK;
 }
 
-::android::status_t DriverStub::transfer(void* buffer, size_t frameCount, size_t* actualFrameCount,
+::android::status_t StreamStub::transfer(void* buffer, size_t frameCount, size_t* actualFrameCount,
                                          int32_t* latencyMs) {
     static constexpr float kMicrosPerSecond = MICROS_PER_SECOND;
     static constexpr float kScaleFactor = .8f;
@@ -79,69 +80,19 @@ DriverStub::DriverStub(const StreamContext& context, bool isInput)
     return ::android::OK;
 }
 
-::android::status_t DriverStub::standby() {
+::android::status_t StreamStub::standby() {
     usleep(500);
     return ::android::OK;
 }
 
-::android::status_t DriverStub::setConnectedDevices(
-        const std::vector<AudioDevice>& connectedDevices __unused) {
-    usleep(500);
-    return ::android::OK;
-}
-
-// static
-ndk::ScopedAStatus StreamInStub::createInstance(const SinkMetadata& sinkMetadata,
-                                                StreamContext&& context,
-                                                const std::vector<MicrophoneInfo>& microphones,
-                                                std::shared_ptr<StreamIn>* result) {
-    std::shared_ptr<StreamIn> stream =
-            ndk::SharedRefBase::make<StreamInStub>(sinkMetadata, std::move(context), microphones);
-    if (auto status = initInstance(stream); !status.isOk()) {
-        return status;
-    }
-    *result = std::move(stream);
-    return ndk::ScopedAStatus::ok();
-}
+void StreamStub::shutdown() {}
 
 StreamInStub::StreamInStub(const SinkMetadata& sinkMetadata, StreamContext&& context,
                            const std::vector<MicrophoneInfo>& microphones)
-    : StreamIn(
-              sinkMetadata, std::move(context),
-              [](const StreamContext& ctx) -> DriverInterface* {
-                  return new DriverStub(ctx, true /*isInput*/);
-              },
-              [](const StreamContext& ctx, DriverInterface* driver) -> StreamWorkerInterface* {
-                  // The default worker implementation is used.
-                  return new StreamInWorker(ctx, driver);
-              },
-              microphones) {}
-
-// static
-ndk::ScopedAStatus StreamOutStub::createInstance(const SourceMetadata& sourceMetadata,
-                                                 StreamContext&& context,
-                                                 const std::optional<AudioOffloadInfo>& offloadInfo,
-                                                 std::shared_ptr<StreamOut>* result) {
-    std::shared_ptr<StreamOut> stream = ndk::SharedRefBase::make<StreamOutStub>(
-            sourceMetadata, std::move(context), offloadInfo);
-    if (auto status = initInstance(stream); !status.isOk()) {
-        return status;
-    }
-    *result = std::move(stream);
-    return ndk::ScopedAStatus::ok();
-}
+    : StreamStub(sinkMetadata, std::move(context)), StreamIn(microphones) {}
 
 StreamOutStub::StreamOutStub(const SourceMetadata& sourceMetadata, StreamContext&& context,
                              const std::optional<AudioOffloadInfo>& offloadInfo)
-    : StreamOut(
-              sourceMetadata, std::move(context),
-              [](const StreamContext& ctx) -> DriverInterface* {
-                  return new DriverStub(ctx, false /*isInput*/);
-              },
-              [](const StreamContext& ctx, DriverInterface* driver) -> StreamWorkerInterface* {
-                  // The default worker implementation is used.
-                  return new StreamOutWorker(ctx, driver);
-              },
-              offloadInfo) {}
+    : StreamStub(sourceMetadata, std::move(context)), StreamOut(offloadInfo) {}
 
 }  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/include/core-impl/Module.h b/audio/aidl/default/include/core-impl/Module.h
index 83ecfaa8c6..4a23637d86 100644
--- a/audio/aidl/default/include/core-impl/Module.h
+++ b/audio/aidl/default/include/core-impl/Module.h
@@ -33,39 +33,13 @@ class Module : public BnModule {
     static constexpr int32_t kLatencyMs = 10;
     enum Type : int { DEFAULT, R_SUBMIX, USB };
 
+    static std::shared_ptr<Module> createInstance(Type type);
+
     explicit Module(Type type) : mType(type) {}
 
-    static std::shared_ptr<Module> createInstance(Type type);
-    static StreamIn::CreateInstance getStreamInCreator(Type type);
-    static StreamOut::CreateInstance getStreamOutCreator(Type type);
-
-  private:
-    struct VendorDebug {
-        static const std::string kForceTransientBurstName;
-        static const std::string kForceSynchronousDrainName;
-        bool forceTransientBurst = false;
-        bool forceSynchronousDrain = false;
-    };
-    // Helper used for interfaces that require a persistent instance. We hold them via a strong
-    // pointer. The binder token is retained for a call to 'setMinSchedulerPolicy'.
-    template <class C>
-    struct ChildInterface : private std::pair<std::shared_ptr<C>, ndk::SpAIBinder> {
-        ChildInterface() {}
-        ChildInterface& operator=(const std::shared_ptr<C>& c) {
-            return operator=(std::shared_ptr<C>(c));
-        }
-        ChildInterface& operator=(std::shared_ptr<C>&& c) {
-            this->first = std::move(c);
-            this->second = this->first->asBinder();
-            AIBinder_setMinSchedulerPolicy(this->second.get(), SCHED_NORMAL,
-                                           ANDROID_PRIORITY_AUDIO);
-            return *this;
-        }
-        explicit operator bool() const { return !!this->first; }
-        C& operator*() const { return *(this->first); }
-        C* operator->() const { return this->first; }
-        std::shared_ptr<C> getPtr() const { return this->first; }
-    };
+  protected:
+    // The vendor extension done via inheritance can override interface methods and augment
+    // a call to the base implementation.
 
     ndk::ScopedAStatus setModuleDebug(
             const ::aidl::android::hardware::audio::core::ModuleDebug& in_debug) override;
@@ -146,29 +120,46 @@ class Module : public BnModule {
     ndk::ScopedAStatus getAAudioMixerBurstCount(int32_t* _aidl_return) override;
     ndk::ScopedAStatus getAAudioHardwareBurstMinUsec(int32_t* _aidl_return) override;
 
-    void cleanUpPatch(int32_t patchId);
-    ndk::ScopedAStatus createStreamContext(
-            int32_t in_portConfigId, int64_t in_bufferSizeFrames,
-            std::shared_ptr<IStreamCallback> asyncCallback,
-            std::shared_ptr<IStreamOutEventCallback> outEventCallback,
-            ::aidl::android::hardware::audio::core::StreamContext* out_context);
-    std::vector<::aidl::android::media::audio::common::AudioDevice> findConnectedDevices(
-            int32_t portConfigId);
-    std::set<int32_t> findConnectedPortConfigIds(int32_t portConfigId);
-    ndk::ScopedAStatus findPortIdForNewStream(
-            int32_t in_portConfigId, ::aidl::android::media::audio::common::AudioPort** port);
-    internal::Configuration& getConfig();
-    template <typename C>
-    std::set<int32_t> portIdsFromPortConfigIds(C portConfigIds);
-    void registerPatch(const AudioPatch& patch);
-    void updateStreamsConnectedState(const AudioPatch& oldPatch, const AudioPatch& newPatch);
-    bool isMmapSupported();
-
     // This value is used for all AudioPatches.
     static constexpr int32_t kMinimumStreamBufferSizeFrames = 256;
     // The maximum stream buffer size is 1 GiB = 2 ** 30 bytes;
     static constexpr int32_t kMaximumStreamBufferSizeBytes = 1 << 30;
 
+  private:
+    struct VendorDebug {
+        static const std::string kForceTransientBurstName;
+        static const std::string kForceSynchronousDrainName;
+        bool forceTransientBurst = false;
+        bool forceSynchronousDrain = false;
+    };
+    // Helper used for interfaces that require a persistent instance. We hold them via a strong
+    // pointer. The binder token is retained for a call to 'setMinSchedulerPolicy'.
+    template <class C>
+    struct ChildInterface : private std::pair<std::shared_ptr<C>, ndk::SpAIBinder> {
+        ChildInterface() {}
+        ChildInterface& operator=(const std::shared_ptr<C>& c) {
+            return operator=(std::shared_ptr<C>(c));
+        }
+        ChildInterface& operator=(std::shared_ptr<C>&& c) {
+            this->first = std::move(c);
+            this->second = this->first->asBinder();
+            AIBinder_setMinSchedulerPolicy(this->second.get(), SCHED_NORMAL,
+                                           ANDROID_PRIORITY_AUDIO);
+            return *this;
+        }
+        explicit operator bool() const { return !!this->first; }
+        C& operator*() const { return *(this->first); }
+        C* operator->() const { return this->first; }
+        std::shared_ptr<C> getPtr() const { return this->first; }
+    };
+    // ids of device ports created at runtime via 'connectExternalDevice'.
+    // Also stores a list of ids of mix ports with dynamic profiles that were populated from
+    // the connected port. This list can be empty, thus an int->int multimap can't be used.
+    using ConnectedDevicePorts = std::map<int32_t, std::vector<int32_t>>;
+    // Maps port ids and port config ids to patch ids.
+    // Multimap because both ports and configs can be used by multiple patches.
+    using Patches = std::multimap<int32_t, int32_t>;
+
     const Type mType;
     std::unique_ptr<internal::Configuration> mConfig;
     ModuleDebug mDebug;
@@ -177,19 +168,29 @@ class Module : public BnModule {
     ChildInterface<IBluetooth> mBluetooth;
     ChildInterface<IBluetoothA2dp> mBluetoothA2dp;
     ChildInterface<IBluetoothLe> mBluetoothLe;
-    // ids of device ports created at runtime via 'connectExternalDevice'.
-    // Also stores ids of mix ports with dynamic profiles which got populated from the connected
-    // port.
-    std::map<int32_t, std::vector<int32_t>> mConnectedDevicePorts;
+    ConnectedDevicePorts mConnectedDevicePorts;
     Streams mStreams;
-    // Maps port ids and port config ids to patch ids.
-    // Multimap because both ports and configs can be used by multiple patches.
-    std::multimap<int32_t, int32_t> mPatches;
+    Patches mPatches;
     bool mMicMute = false;
+    bool mMasterMute = false;
+    float mMasterVolume = 1.0f;
     ChildInterface<sounddose::ISoundDose> mSoundDose;
     std::optional<bool> mIsMmapSupported;
 
   protected:
+    // The following virtual functions are intended for vendor extension via inheritance.
+
+    virtual ndk::ScopedAStatus createInputStream(
+            const ::aidl::android::hardware::audio::common::SinkMetadata& sinkMetadata,
+            StreamContext&& context,
+            const std::vector<::aidl::android::media::audio::common::MicrophoneInfo>& microphones,
+            std::shared_ptr<StreamIn>* result);
+    virtual ndk::ScopedAStatus createOutputStream(
+            const ::aidl::android::hardware::audio::common::SourceMetadata& sourceMetadata,
+            StreamContext&& context,
+            const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
+                    offloadInfo,
+            std::shared_ptr<StreamOut>* result);
     // If the module is unable to populate the connected device port correctly, the returned error
     // code must correspond to the errors of `IModule.connectedExternalDevice` method.
     virtual ndk::ScopedAStatus populateConnectedDevicePort(
@@ -204,8 +205,31 @@ class Module : public BnModule {
     virtual ndk::ScopedAStatus onMasterMuteChanged(bool mute);
     virtual ndk::ScopedAStatus onMasterVolumeChanged(float volume);
 
-    bool mMasterMute = false;
-    float mMasterVolume = 1.0f;
+    // Utility and helper functions accessible to subclasses.
+    void cleanUpPatch(int32_t patchId);
+    ndk::ScopedAStatus createStreamContext(
+            int32_t in_portConfigId, int64_t in_bufferSizeFrames,
+            std::shared_ptr<IStreamCallback> asyncCallback,
+            std::shared_ptr<IStreamOutEventCallback> outEventCallback,
+            ::aidl::android::hardware::audio::core::StreamContext* out_context);
+    std::vector<::aidl::android::media::audio::common::AudioDevice> findConnectedDevices(
+            int32_t portConfigId);
+    std::set<int32_t> findConnectedPortConfigIds(int32_t portConfigId);
+    ndk::ScopedAStatus findPortIdForNewStream(
+            int32_t in_portConfigId, ::aidl::android::media::audio::common::AudioPort** port);
+    internal::Configuration& getConfig();
+    const ConnectedDevicePorts& getConnectedDevicePorts() const { return mConnectedDevicePorts; }
+    bool getMasterMute() const { return mMasterMute; }
+    bool getMasterVolume() const { return mMasterVolume; }
+    bool getMicMute() const { return mMicMute; }
+    const Patches& getPatches() const { return mPatches; }
+    const Streams& getStreams() const { return mStreams; }
+    bool isMmapSupported();
+    template <typename C>
+    std::set<int32_t> portIdsFromPortConfigIds(C portConfigIds);
+    void registerPatch(const AudioPatch& patch);
+    ndk::ScopedAStatus updateStreamsConnectedState(const AudioPatch& oldPatch,
+                                                   const AudioPatch& newPatch);
 };
 
 }  // namespace aidl::android::hardware::audio::core
diff --git a/audio/aidl/default/include/core-impl/ModuleUsb.h b/audio/aidl/default/include/core-impl/ModuleUsb.h
index 1aa22445b4..5a5429db64 100644
--- a/audio/aidl/default/include/core-impl/ModuleUsb.h
+++ b/audio/aidl/default/include/core-impl/ModuleUsb.h
@@ -32,6 +32,17 @@ class ModuleUsb : public Module {
     ndk::ScopedAStatus setMicMute(bool in_mute) override;
 
     // Module interfaces
+    ndk::ScopedAStatus createInputStream(
+            const ::aidl::android::hardware::audio::common::SinkMetadata& sinkMetadata,
+            StreamContext&& context,
+            const std::vector<::aidl::android::media::audio::common::MicrophoneInfo>& microphones,
+            std::shared_ptr<StreamIn>* result) override;
+    ndk::ScopedAStatus createOutputStream(
+            const ::aidl::android::hardware::audio::common::SourceMetadata& sourceMetadata,
+            StreamContext&& context,
+            const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
+                    offloadInfo,
+            std::shared_ptr<StreamOut>* result) override;
     ndk::ScopedAStatus populateConnectedDevicePort(
             ::aidl::android::media::audio::common::AudioPort* audioPort) override;
     ndk::ScopedAStatus checkAudioPatchEndpointsMatch(
diff --git a/audio/aidl/default/include/core-impl/Stream.h b/audio/aidl/default/include/core-impl/Stream.h
index 476f1ff30d..c20a4213ed 100644
--- a/audio/aidl/default/include/core-impl/Stream.h
+++ b/audio/aidl/default/include/core-impl/Stream.h
@@ -25,6 +25,7 @@
 #include <variant>
 
 #include <StreamWorker.h>
+#include <Utils.h>
 #include <aidl/android/hardware/audio/common/SinkMetadata.h>
 #include <aidl/android/hardware/audio/common/SourceMetadata.h>
 #include <aidl/android/hardware/audio/core/BnStreamCommon.h>
@@ -34,8 +35,10 @@
 #include <aidl/android/hardware/audio/core/IStreamOutEventCallback.h>
 #include <aidl/android/hardware/audio/core/StreamDescriptor.h>
 #include <aidl/android/media/audio/common/AudioDevice.h>
+#include <aidl/android/media/audio/common/AudioIoFlags.h>
 #include <aidl/android/media/audio/common/AudioOffloadInfo.h>
 #include <aidl/android/media/audio/common/MicrophoneInfo.h>
+#include <error/expected_utils.h>
 #include <fmq/AidlMessageQueue.h>
 #include <system/thread_defs.h>
 #include <utils/Errors.h>
@@ -77,7 +80,8 @@ class StreamContext {
     StreamContext(std::unique_ptr<CommandMQ> commandMQ, std::unique_ptr<ReplyMQ> replyMQ,
                   const ::aidl::android::media::audio::common::AudioFormatDescription& format,
                   const ::aidl::android::media::audio::common::AudioChannelLayout& channelLayout,
-                  int sampleRate, std::unique_ptr<DataMQ> dataMQ,
+                  int sampleRate, const ::aidl::android::media::audio::common::AudioIoFlags& flags,
+                  int32_t mixPortHandle, std::unique_ptr<DataMQ> dataMQ,
                   std::shared_ptr<IStreamCallback> asyncCallback,
                   std::shared_ptr<IStreamOutEventCallback> outEventCallback,
                   DebugParameters debugParameters)
@@ -87,6 +91,8 @@ class StreamContext {
           mFormat(format),
           mChannelLayout(channelLayout),
           mSampleRate(sampleRate),
+          mFlags(flags),
+          mMixPortHandle(mixPortHandle),
           mDataMQ(std::move(dataMQ)),
           mAsyncCallback(asyncCallback),
           mOutEventCallback(outEventCallback),
@@ -98,6 +104,8 @@ class StreamContext {
           mFormat(other.mFormat),
           mChannelLayout(other.mChannelLayout),
           mSampleRate(other.mSampleRate),
+          mFlags(std::move(other.mFlags)),
+          mMixPortHandle(other.mMixPortHandle),
           mDataMQ(std::move(other.mDataMQ)),
           mAsyncCallback(std::move(other.mAsyncCallback)),
           mOutEventCallback(std::move(other.mOutEventCallback)),
@@ -109,6 +117,8 @@ class StreamContext {
         mFormat = std::move(other.mFormat);
         mChannelLayout = std::move(other.mChannelLayout);
         mSampleRate = other.mSampleRate;
+        mFlags = std::move(other.mFlags);
+        mMixPortHandle = other.mMixPortHandle;
         mDataMQ = std::move(other.mDataMQ);
         mAsyncCallback = std::move(other.mAsyncCallback);
         mOutEventCallback = std::move(other.mOutEventCallback);
@@ -126,10 +136,12 @@ class StreamContext {
     ::aidl::android::media::audio::common::AudioFormatDescription getFormat() const {
         return mFormat;
     }
+    ::aidl::android::media::audio::common::AudioIoFlags getFlags() const { return mFlags; }
     bool getForceTransientBurst() const { return mDebugParameters.forceTransientBurst; }
     bool getForceSynchronousDrain() const { return mDebugParameters.forceSynchronousDrain; }
     size_t getFrameSize() const;
     int getInternalCommandCookie() const { return mInternalCommandCookie; }
+    int32_t getMixPortHandle() const { return mMixPortHandle; }
     std::shared_ptr<IStreamOutEventCallback> getOutEventCallback() const {
         return mOutEventCallback;
     }
@@ -146,14 +158,16 @@ class StreamContext {
     ::aidl::android::media::audio::common::AudioFormatDescription mFormat;
     ::aidl::android::media::audio::common::AudioChannelLayout mChannelLayout;
     int mSampleRate;
+    ::aidl::android::media::audio::common::AudioIoFlags mFlags;
+    int32_t mMixPortHandle;
     std::unique_ptr<DataMQ> mDataMQ;
     std::shared_ptr<IStreamCallback> mAsyncCallback;
     std::shared_ptr<IStreamOutEventCallback> mOutEventCallback;  // Only used by output streams
     DebugParameters mDebugParameters;
 };
 
+// This interface provides operations of the stream which are executed on the worker thread.
 struct DriverInterface {
-    using CreateInstance = std::function<DriverInterface*(const StreamContext&)>;
     virtual ~DriverInterface() = default;
     // All the methods below are called on the worker thread.
     virtual ::android::status_t init() = 0;  // This function is only called once.
@@ -163,11 +177,7 @@ struct DriverInterface {
     virtual ::android::status_t transfer(void* buffer, size_t frameCount, size_t* actualFrameCount,
                                          int32_t* latencyMs) = 0;
     virtual ::android::status_t standby() = 0;
-    // The method below is called from a thread of the Binder pool. Access to data shared with other
-    // methods of this interface must be done in a thread-safe manner.
-    virtual ::android::status_t setConnectedDevices(
-            const std::vector<::aidl::android::media::audio::common::AudioDevice>&
-                    connectedDevices) = 0;
+    virtual void shutdown() = 0;  // This function is only called once.
 };
 
 class StreamWorkerCommonLogic : public ::android::hardware::audio::common::StreamLogic {
@@ -284,14 +294,20 @@ class StreamOutWorkerLogic : public StreamWorkerCommonLogic {
 };
 using StreamOutWorker = StreamWorkerImpl<StreamOutWorkerLogic>;
 
-// This provides a C++ interface with methods of the IStreamCommon Binder interface,
-// but intentionally does not inherit from it. This is needed to avoid inheriting
-// StreamIn and StreamOut from two Binder interface classes, as these parts of the class
-// will be reference counted separately.
-//
-// The implementation of these common methods is in the StreamCommonImpl template class.
+// This interface provides operations of the stream which are executed on a Binder pool thread.
+// These methods originate both from the AIDL interface and its implementation.
 struct StreamCommonInterface {
+    using ConnectedDevices = std::vector<::aidl::android::media::audio::common::AudioDevice>;
+    using Metadata =
+            std::variant<::aidl::android::hardware::audio::common::SinkMetadata /*IStreamIn*/,
+                         ::aidl::android::hardware::audio::common::SourceMetadata /*IStreamOut*/>;
+
+    static constexpr bool isInput(const Metadata& metadata) { return metadata.index() == 0; }
+
     virtual ~StreamCommonInterface() = default;
+    // Methods below originate from the 'IStreamCommon' interface.
+    // This is semantically equivalent to inheriting from 'IStreamCommon' with a benefit
+    // that concrete stream implementations can inherit both from this interface and IStreamIn/Out.
     virtual ndk::ScopedAStatus close() = 0;
     virtual ndk::ScopedAStatus prepareToClose() = 0;
     virtual ndk::ScopedAStatus updateHwAvSyncId(int32_t in_hwAvSyncId) = 0;
@@ -305,11 +321,30 @@ struct StreamCommonInterface {
     virtual ndk::ScopedAStatus removeEffect(
             const std::shared_ptr<::aidl::android::hardware::audio::effect::IEffect>&
                     in_effect) = 0;
+    // Methods below are common for both 'IStreamIn' and 'IStreamOut'. Note that
+    // 'updateMetadata' in them uses an individual structure which is wrapped here.
+    // The 'Common' suffix is added to distinguish them from the methods from 'IStreamIn/Out'.
+    virtual ndk::ScopedAStatus getStreamCommonCommon(
+            std::shared_ptr<IStreamCommon>* _aidl_return) = 0;
+    virtual ndk::ScopedAStatus updateMetadataCommon(const Metadata& metadata) = 0;
+    // Methods below are called by implementation of 'IModule', 'IStreamIn' and 'IStreamOut'.
+    virtual ndk::ScopedAStatus initInstance(
+            const std::shared_ptr<StreamCommonInterface>& delegate) = 0;
+    virtual const StreamContext& getContext() const = 0;
+    virtual bool isClosed() const = 0;
+    virtual const ConnectedDevices& getConnectedDevices() const = 0;
+    virtual ndk::ScopedAStatus setConnectedDevices(
+            const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices) = 0;
 };
 
-class StreamCommon : public BnStreamCommon {
+// This is equivalent to automatically generated 'IStreamCommonDelegator' but uses
+// a weak pointer to avoid creating a reference loop. The loop will occur because
+// 'IStreamIn/Out.getStreamCommon' must return the same instance every time, thus
+// the stream implementation must hold a strong pointer to an instance of 'IStreamCommon'.
+// Also, we use 'StreamCommonInterface' here instead of 'IStreamCommon'.
+class StreamCommonDelegator : public BnStreamCommon {
   public:
-    explicit StreamCommon(const std::shared_ptr<StreamCommonInterface>& delegate)
+    explicit StreamCommonDelegator(const std::shared_ptr<StreamCommonInterface>& delegate)
         : mDelegate(delegate) {}
 
   private:
@@ -360,9 +395,20 @@ class StreamCommon : public BnStreamCommon {
     std::weak_ptr<StreamCommonInterface> mDelegate;
 };
 
-template <class Metadata>
-class StreamCommonImpl : public StreamCommonInterface {
+// The implementation of DriverInterface must be provided by each concrete stream implementation.
+class StreamCommonImpl : virtual public StreamCommonInterface, virtual public DriverInterface {
   public:
+    StreamCommonImpl(const Metadata& metadata, StreamContext&& context,
+                     const StreamWorkerInterface::CreateInstance& createWorker)
+        : mMetadata(metadata),
+          mContext(std::move(context)),
+          mWorker(createWorker(mContext, this)) {}
+    StreamCommonImpl(const Metadata& metadata, StreamContext&& context)
+        : StreamCommonImpl(
+                  metadata, std::move(context),
+                  isInput(metadata) ? getDefaultInWorkerCreator() : getDefaultOutWorkerCreator()) {}
+    ~StreamCommonImpl();
+
     ndk::ScopedAStatus close() override;
     ndk::ScopedAStatus prepareToClose() override;
     ndk::ScopedAStatus updateHwAvSyncId(int32_t in_hwAvSyncId) override;
@@ -377,46 +423,50 @@ class StreamCommonImpl : public StreamCommonInterface {
             const std::shared_ptr<::aidl::android::hardware::audio::effect::IEffect>& in_effect)
             override;
 
-    ndk::ScopedAStatus getStreamCommon(std::shared_ptr<IStreamCommon>* _aidl_return);
-    ndk::ScopedAStatus init() {
-        return mWorker->start() ? ndk::ScopedAStatus::ok()
-                                : ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
-    }
-    bool isClosed() const { return mWorker->isClosed(); }
-    void setIsConnected(
-            const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices) {
-        mWorker->setIsConnected(!devices.empty());
-        mConnectedDevices = devices;
-        mDriver->setConnectedDevices(devices);
-    }
-    ndk::ScopedAStatus updateMetadata(const Metadata& metadata);
+    ndk::ScopedAStatus getStreamCommonCommon(std::shared_ptr<IStreamCommon>* _aidl_return) override;
+    ndk::ScopedAStatus updateMetadataCommon(const Metadata& metadata) override;
+
+    ndk::ScopedAStatus initInstance(
+            const std::shared_ptr<StreamCommonInterface>& delegate) override;
+    const StreamContext& getContext() const override { return mContext; }
+    bool isClosed() const override { return mWorker->isClosed(); }
+    const ConnectedDevices& getConnectedDevices() const override { return mConnectedDevices; }
+    ndk::ScopedAStatus setConnectedDevices(
+            const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices)
+            override;
 
   protected:
-    StreamCommonImpl(const Metadata& metadata, StreamContext&& context,
-                     const DriverInterface::CreateInstance& createDriver,
-                     const StreamWorkerInterface::CreateInstance& createWorker)
-        : mMetadata(metadata),
-          mContext(std::move(context)),
-          mDriver(createDriver(mContext)),
-          mWorker(createWorker(mContext, mDriver.get())) {}
-    ~StreamCommonImpl();
-    void stopWorker();
-    void createStreamCommon(const std::shared_ptr<StreamCommonInterface>& delegate);
+    static StreamWorkerInterface::CreateInstance getDefaultInWorkerCreator() {
+        return [](const StreamContext& ctx, DriverInterface* driver) -> StreamWorkerInterface* {
+            return new StreamInWorker(ctx, driver);
+        };
+    }
+    static StreamWorkerInterface::CreateInstance getDefaultOutWorkerCreator() {
+        return [](const StreamContext& ctx, DriverInterface* driver) -> StreamWorkerInterface* {
+            return new StreamOutWorker(ctx, driver);
+        };
+    }
+
+    void stopWorker();
 
-    std::shared_ptr<StreamCommon> mCommon;
-    ndk::SpAIBinder mCommonBinder;
     Metadata mMetadata;
     StreamContext mContext;
-    std::unique_ptr<DriverInterface> mDriver;
     std::unique_ptr<StreamWorkerInterface> mWorker;
-    std::vector<::aidl::android::media::audio::common::AudioDevice> mConnectedDevices;
+    std::shared_ptr<StreamCommonDelegator> mCommon;
+    ndk::SpAIBinder mCommonBinder;
+    ConnectedDevices mConnectedDevices;
 };
 
-class StreamIn : public StreamCommonImpl<::aidl::android::hardware::audio::common::SinkMetadata>,
-                 public BnStreamIn {
+// Note: 'StreamIn/Out' can not be used on their own. Instead, they must be used for defining
+// concrete input/output stream implementations.
+class StreamIn : virtual public StreamCommonInterface, public BnStreamIn {
+  protected:
     ndk::ScopedAStatus getStreamCommon(std::shared_ptr<IStreamCommon>* _aidl_return) override {
-        return StreamCommonImpl<::aidl::android::hardware::audio::common::SinkMetadata>::
-                getStreamCommon(_aidl_return);
+        return getStreamCommonCommon(_aidl_return);
+    }
+    ndk::ScopedAStatus updateMetadata(const ::aidl::android::hardware::audio::common::SinkMetadata&
+                                              in_sinkMetadata) override {
+        return updateMetadataCommon(in_sinkMetadata);
     }
     ndk::ScopedAStatus getActiveMicrophones(
             std::vector<::aidl::android::media::audio::common::MicrophoneDynamicInfo>* _aidl_return)
@@ -425,49 +475,26 @@ class StreamIn : public StreamCommonImpl<::aidl::android::hardware::audio::commo
     ndk::ScopedAStatus setMicrophoneDirection(MicrophoneDirection in_direction) override;
     ndk::ScopedAStatus getMicrophoneFieldDimension(float* _aidl_return) override;
     ndk::ScopedAStatus setMicrophoneFieldDimension(float in_zoom) override;
-    ndk::ScopedAStatus updateMetadata(const ::aidl::android::hardware::audio::common::SinkMetadata&
-                                              in_sinkMetadata) override {
-        return StreamCommonImpl<::aidl::android::hardware::audio::common::SinkMetadata>::
-                updateMetadata(in_sinkMetadata);
-    }
     ndk::ScopedAStatus getHwGain(std::vector<float>* _aidl_return) override;
     ndk::ScopedAStatus setHwGain(const std::vector<float>& in_channelGains) override;
 
-  protected:
     friend class ndk::SharedRefBase;
 
-    static ndk::ScopedAStatus initInstance(const std::shared_ptr<StreamIn>& stream);
-
-    StreamIn(const ::aidl::android::hardware::audio::common::SinkMetadata& sinkMetadata,
-             StreamContext&& context, const DriverInterface::CreateInstance& createDriver,
-             const StreamWorkerInterface::CreateInstance& createWorker,
-             const std::vector<::aidl::android::media::audio::common::MicrophoneInfo>& microphones);
-    void createStreamCommon(const std::shared_ptr<StreamIn>& myPtr) {
-        StreamCommonImpl<
-                ::aidl::android::hardware::audio::common::SinkMetadata>::createStreamCommon(myPtr);
-    }
+    explicit StreamIn(
+            const std::vector<::aidl::android::media::audio::common::MicrophoneInfo>& microphones);
 
     const std::map<::aidl::android::media::audio::common::AudioDevice, std::string> mMicrophones;
-
-  public:
-    using CreateInstance = std::function<ndk::ScopedAStatus(
-            const ::aidl::android::hardware::audio::common::SinkMetadata& sinkMetadata,
-            StreamContext&& context,
-            const std::vector<::aidl::android::media::audio::common::MicrophoneInfo>& microphones,
-            std::shared_ptr<StreamIn>* result)>;
 };
 
-class StreamOut : public StreamCommonImpl<::aidl::android::hardware::audio::common::SourceMetadata>,
-                  public BnStreamOut {
+class StreamOut : virtual public StreamCommonInterface, public BnStreamOut {
+  protected:
     ndk::ScopedAStatus getStreamCommon(std::shared_ptr<IStreamCommon>* _aidl_return) override {
-        return StreamCommonImpl<::aidl::android::hardware::audio::common::SourceMetadata>::
-                getStreamCommon(_aidl_return);
+        return getStreamCommonCommon(_aidl_return);
     }
     ndk::ScopedAStatus updateMetadata(
             const ::aidl::android::hardware::audio::common::SourceMetadata& in_sourceMetadata)
             override {
-        return StreamCommonImpl<::aidl::android::hardware::audio::common::SourceMetadata>::
-                updateMetadata(in_sourceMetadata);
+        return updateMetadataCommon(in_sourceMetadata);
     }
     ndk::ScopedAStatus updateOffloadMetadata(
             const ::aidl::android::hardware::audio::common::AudioOffloadMetadata&
@@ -492,34 +519,27 @@ class StreamOut : public StreamCommonImpl<::aidl::android::hardware::audio::comm
             override;
     ndk::ScopedAStatus selectPresentation(int32_t in_presentationId, int32_t in_programId) override;
 
-    void createStreamCommon(const std::shared_ptr<StreamOut>& myPtr) {
-        StreamCommonImpl<::aidl::android::hardware::audio::common::SourceMetadata>::
-                createStreamCommon(myPtr);
-    }
-
-  protected:
     friend class ndk::SharedRefBase;
 
-    static ndk::ScopedAStatus initInstance(const std::shared_ptr<StreamOut>& stream);
-
-    StreamOut(const ::aidl::android::hardware::audio::common::SourceMetadata& sourceMetadata,
-              StreamContext&& context, const DriverInterface::CreateInstance& createDriver,
-              const StreamWorkerInterface::CreateInstance& createWorker,
-              const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
-                      offloadInfo);
+    explicit StreamOut(const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
+                               offloadInfo);
 
     std::optional<::aidl::android::media::audio::common::AudioOffloadInfo> mOffloadInfo;
     std::optional<::aidl::android::hardware::audio::common::AudioOffloadMetadata> mOffloadMetadata;
-
-  public:
-    using CreateInstance = std::function<ndk::ScopedAStatus(
-            const ::aidl::android::hardware::audio::common::SourceMetadata& sourceMetadata,
-            StreamContext&& context,
-            const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
-                    offloadInfo,
-            std::shared_ptr<StreamOut>* result)>;
 };
 
+// The recommended way to create a stream instance.
+// 'StreamImpl' is the concrete stream implementation, 'StreamInOrOut' is either 'StreamIn' or
+// 'StreamOut', the rest are the arguments forwarded to the constructor of 'StreamImpl'.
+template <class StreamImpl, class StreamInOrOut, class... Args>
+ndk::ScopedAStatus createStreamInstance(std::shared_ptr<StreamInOrOut>* result, Args&&... args) {
+    std::shared_ptr<StreamInOrOut> stream =
+            ::ndk::SharedRefBase::make<StreamImpl>(std::forward<Args>(args)...);
+    RETURN_STATUS_IF_ERROR(stream->initInstance(stream));
+    *result = std::move(stream);
+    return ndk::ScopedAStatus::ok();
+}
+
 class StreamWrapper {
   public:
     explicit StreamWrapper(const std::shared_ptr<StreamIn>& streamIn)
@@ -528,25 +548,18 @@ class StreamWrapper {
         : mStream(streamOut), mStreamBinder(streamOut->asBinder()) {}
     ndk::SpAIBinder getBinder() const { return mStreamBinder; }
     bool isStreamOpen() const {
-        return std::visit(
-                [](auto&& ws) -> bool {
-                    auto s = ws.lock();
-                    return s && !s->isClosed();
-                },
-                mStream);
+        auto s = mStream.lock();
+        return s && !s->isClosed();
     }
-    void setStreamIsConnected(
+    ndk::ScopedAStatus setConnectedDevices(
             const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices) {
-        std::visit(
-                [&](auto&& ws) {
-                    auto s = ws.lock();
-                    if (s) s->setIsConnected(devices);
-                },
-                mStream);
+        auto s = mStream.lock();
+        if (s) return s->setConnectedDevices(devices);
+        return ndk::ScopedAStatus::ok();
     }
 
   private:
-    std::variant<std::weak_ptr<StreamIn>, std::weak_ptr<StreamOut>> mStream;
+    std::weak_ptr<StreamCommonInterface> mStream;
     ndk::SpAIBinder mStreamBinder;
 };
 
@@ -564,12 +577,13 @@ class Streams {
         mStreams.insert(std::pair{portConfigId, sw});
         mStreams.insert(std::pair{portId, std::move(sw)});
     }
-    void setStreamIsConnected(
+    ndk::ScopedAStatus setStreamConnectedDevices(
             int32_t portConfigId,
             const std::vector<::aidl::android::media::audio::common::AudioDevice>& devices) {
         if (auto it = mStreams.find(portConfigId); it != mStreams.end()) {
-            it->second.setStreamIsConnected(devices);
+            return it->second.setConnectedDevices(devices);
         }
+        return ndk::ScopedAStatus::ok();
     }
 
   private:
diff --git a/audio/aidl/default/include/core-impl/StreamStub.h b/audio/aidl/default/include/core-impl/StreamStub.h
index 436e610ccf..c8900f3223 100644
--- a/audio/aidl/default/include/core-impl/StreamStub.h
+++ b/audio/aidl/default/include/core-impl/StreamStub.h
@@ -20,9 +20,10 @@
 
 namespace aidl::android::hardware::audio::core {
 
-class DriverStub : public DriverInterface {
+class StreamStub : public StreamCommonImpl {
   public:
-    DriverStub(const StreamContext& context, bool isInput);
+    StreamStub(const Metadata& metadata, StreamContext&& context);
+    // Methods of 'DriverInterface'.
     ::android::status_t init() override;
     ::android::status_t drain(StreamDescriptor::DrainMode) override;
     ::android::status_t flush() override;
@@ -30,10 +31,7 @@ class DriverStub : public DriverInterface {
     ::android::status_t transfer(void* buffer, size_t frameCount, size_t* actualFrameCount,
                                  int32_t* latencyMs) override;
     ::android::status_t standby() override;
-    // Note: called on a different thread.
-    ::android::status_t setConnectedDevices(
-            const std::vector<::aidl::android::media::audio::common::AudioDevice>& connectedDevices)
-            override;
+    void shutdown() override;
 
   private:
     const size_t mFrameSizeBytes;
@@ -42,15 +40,8 @@ class DriverStub : public DriverInterface {
     const bool mIsInput;
 };
 
-class StreamInStub final : public StreamIn {
+class StreamInStub final : public StreamStub, public StreamIn {
   public:
-    static ndk::ScopedAStatus createInstance(
-            const ::aidl::android::hardware::audio::common::SinkMetadata& sinkMetadata,
-            StreamContext&& context,
-            const std::vector<::aidl::android::media::audio::common::MicrophoneInfo>& microphones,
-            std::shared_ptr<StreamIn>* result);
-
-  private:
     friend class ndk::SharedRefBase;
     StreamInStub(
             const ::aidl::android::hardware::audio::common::SinkMetadata& sinkMetadata,
@@ -58,16 +49,8 @@ class StreamInStub final : public StreamIn {
             const std::vector<::aidl::android::media::audio::common::MicrophoneInfo>& microphones);
 };
 
-class StreamOutStub final : public StreamOut {
+class StreamOutStub final : public StreamStub, public StreamOut {
   public:
-    static ndk::ScopedAStatus createInstance(
-            const ::aidl::android::hardware::audio::common::SourceMetadata& sourceMetadata,
-            StreamContext&& context,
-            const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
-                    offloadInfo,
-            std::shared_ptr<StreamOut>* result);
-
-  private:
     friend class ndk::SharedRefBase;
     StreamOutStub(const ::aidl::android::hardware::audio::common::SourceMetadata& sourceMetadata,
                   StreamContext&& context,
diff --git a/audio/aidl/default/include/core-impl/StreamUsb.h b/audio/aidl/default/include/core-impl/StreamUsb.h
index 05d889a713..5e55cd8cb8 100644
--- a/audio/aidl/default/include/core-impl/StreamUsb.h
+++ b/audio/aidl/default/include/core-impl/StreamUsb.h
@@ -30,9 +30,10 @@ extern "C" {
 
 namespace aidl::android::hardware::audio::core {
 
-class DriverUsb : public DriverInterface {
+class StreamUsb : public StreamCommonImpl {
   public:
-    DriverUsb(const StreamContext& context, bool isInput);
+    StreamUsb(const Metadata& metadata, StreamContext&& context);
+    // Methods of 'DriverInterface'.
     ::android::status_t init() override;
     ::android::status_t drain(StreamDescriptor::DrainMode) override;
     ::android::status_t flush() override;
@@ -40,62 +41,47 @@ class DriverUsb : public DriverInterface {
     ::android::status_t transfer(void* buffer, size_t frameCount, size_t* actualFrameCount,
                                  int32_t* latencyMs) override;
     ::android::status_t standby() override;
-    // Note: called on a different thread.
-    ::android::status_t setConnectedDevices(
-            const std::vector<::aidl::android::media::audio::common::AudioDevice>& connectedDevices)
-            override;
+    void shutdown() override;
+
+    // Overridden methods of 'StreamCommonImpl', called on a Binder thread.
+    const ConnectedDevices& getConnectedDevices() const override;
+    ndk::ScopedAStatus setConnectedDevices(const ConnectedDevices& devices) override;
 
   private:
     ::android::status_t exitStandby();
 
-    std::mutex mLock;
+    mutable std::mutex mLock;
 
     const size_t mFrameSizeBytes;
     std::optional<struct pcm_config> mConfig;
     const bool mIsInput;
-    // Cached device addresses for connected devices.
-    std::vector<::aidl::android::media::audio::common::AudioDeviceAddress> mConnectedDevices
-            GUARDED_BY(mLock);
     std::vector<std::shared_ptr<alsa_device_proxy>> mAlsaDeviceProxies GUARDED_BY(mLock);
     bool mIsStandby = true;
 };
 
-class StreamInUsb final : public StreamIn {
-    ndk::ScopedAStatus getActiveMicrophones(
-            std::vector<::aidl::android::media::audio::common::MicrophoneDynamicInfo>* _aidl_return)
-            override;
-
+class StreamInUsb final : public StreamUsb, public StreamIn {
   public:
-    static ndk::ScopedAStatus createInstance(
-            const ::aidl::android::hardware::audio::common::SinkMetadata& sinkMetadata,
-            StreamContext&& context,
-            const std::vector<::aidl::android::media::audio::common::MicrophoneInfo>& microphones,
-            std::shared_ptr<StreamIn>* result);
-
-  private:
     friend class ndk::SharedRefBase;
     StreamInUsb(
             const ::aidl::android::hardware::audio::common::SinkMetadata& sinkMetadata,
             StreamContext&& context,
             const std::vector<::aidl::android::media::audio::common::MicrophoneInfo>& microphones);
-};
-
-class StreamOutUsb final : public StreamOut {
-  public:
-    static ndk::ScopedAStatus createInstance(
-            const ::aidl::android::hardware::audio::common::SourceMetadata& sourceMetadata,
-            StreamContext&& context,
-            const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
-                    offloadInfo,
-            std::shared_ptr<StreamOut>* result);
 
   private:
+    ndk::ScopedAStatus getActiveMicrophones(
+            std::vector<::aidl::android::media::audio::common::MicrophoneDynamicInfo>* _aidl_return)
+            override;
+};
+
+class StreamOutUsb final : public StreamUsb, public StreamOut {
+  public:
     friend class ndk::SharedRefBase;
     StreamOutUsb(const ::aidl::android::hardware::audio::common::SourceMetadata& sourceMetadata,
                  StreamContext&& context,
                  const std::optional<::aidl::android::media::audio::common::AudioOffloadInfo>&
                          offloadInfo);
 
+  private:
     ndk::ScopedAStatus getHwVolume(std::vector<float>* _aidl_return) override;
     ndk::ScopedAStatus setHwVolume(const std::vector<float>& in_channelVolumes) override;
 
diff --git a/audio/aidl/default/usb/ModuleUsb.cpp b/audio/aidl/default/usb/ModuleUsb.cpp
index ecdbd5cb77..9d3f21d505 100644
--- a/audio/aidl/default/usb/ModuleUsb.cpp
+++ b/audio/aidl/default/usb/ModuleUsb.cpp
@@ -25,22 +25,27 @@
 #include "UsbAlsaMixerControl.h"
 #include "UsbAlsaUtils.h"
 #include "core-impl/ModuleUsb.h"
+#include "core-impl/StreamUsb.h"
 
 extern "C" {
 #include "alsa_device_profile.h"
 }
 
 using aidl::android::hardware::audio::common::isUsbInputDeviceType;
+using aidl::android::hardware::audio::common::SinkMetadata;
+using aidl::android::hardware::audio::common::SourceMetadata;
 using aidl::android::media::audio::common::AudioChannelLayout;
 using aidl::android::media::audio::common::AudioDeviceAddress;
 using aidl::android::media::audio::common::AudioDeviceDescription;
 using aidl::android::media::audio::common::AudioDeviceType;
 using aidl::android::media::audio::common::AudioFormatDescription;
 using aidl::android::media::audio::common::AudioFormatType;
+using aidl::android::media::audio::common::AudioOffloadInfo;
 using aidl::android::media::audio::common::AudioPort;
 using aidl::android::media::audio::common::AudioPortConfig;
 using aidl::android::media::audio::common::AudioPortExt;
 using aidl::android::media::audio::common::AudioProfile;
+using aidl::android::media::audio::common::MicrophoneInfo;
 
 namespace aidl::android::hardware::audio::core {
 
@@ -97,6 +102,25 @@ ndk::ScopedAStatus ModuleUsb::setMicMute(bool in_mute __unused) {
     return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
 }
 
+ndk::ScopedAStatus ModuleUsb::createInputStream(const SinkMetadata& sinkMetadata,
+                                                StreamContext&& context,
+                                                const std::vector<MicrophoneInfo>& microphones,
+                                                std::shared_ptr<StreamIn>* result) {
+    return createStreamInstance<StreamInUsb>(result, sinkMetadata, std::move(context), microphones);
+}
+
+ndk::ScopedAStatus ModuleUsb::createOutputStream(const SourceMetadata& sourceMetadata,
+                                                 StreamContext&& context,
+                                                 const std::optional<AudioOffloadInfo>& offloadInfo,
+                                                 std::shared_ptr<StreamOut>* result) {
+    if (offloadInfo.has_value()) {
+        LOG(ERROR) << __func__ << ": offload is not supported";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+    return createStreamInstance<StreamOutUsb>(result, sourceMetadata, std::move(context),
+                                              offloadInfo);
+}
+
 ndk::ScopedAStatus ModuleUsb::populateConnectedDevicePort(AudioPort* audioPort) {
     if (audioPort->ext.getTag() != AudioPortExt::Tag::device) {
         LOG(ERROR) << __func__ << ": port id " << audioPort->id << " is not a device port";
@@ -175,8 +199,8 @@ void ModuleUsb::onExternalDeviceConnectionChanged(
         return;
     }
     const int card = address.get<AudioDeviceAddress::alsa>()[0];
-    usb::UsbAlsaMixerControl::getInstance().setDeviceConnectionState(card, mMasterMute,
-                                                                     mMasterVolume, connected);
+    usb::UsbAlsaMixerControl::getInstance().setDeviceConnectionState(card, getMasterMute(),
+                                                                     getMasterVolume(), connected);
 }
 
 ndk::ScopedAStatus ModuleUsb::onMasterMuteChanged(bool mute) {
diff --git a/audio/aidl/default/usb/StreamUsb.cpp b/audio/aidl/default/usb/StreamUsb.cpp
index 9ac1cc9b77..49bc1d67a0 100644
--- a/audio/aidl/default/usb/StreamUsb.cpp
+++ b/audio/aidl/default/usb/StreamUsb.cpp
@@ -18,6 +18,7 @@
 #include <android-base/logging.h>
 
 #include <Utils.h>
+#include <error/expected_utils.h>
 
 #include "UsbAlsaMixerControl.h"
 #include "UsbAlsaUtils.h"
@@ -42,10 +43,12 @@ using android::status_t;
 
 namespace aidl::android::hardware::audio::core {
 
-DriverUsb::DriverUsb(const StreamContext& context, bool isInput)
-    : mFrameSizeBytes(context.getFrameSize()), mIsInput(isInput) {
+StreamUsb::StreamUsb(const Metadata& metadata, StreamContext&& context)
+    : StreamCommonImpl(metadata, std::move(context)),
+      mFrameSizeBytes(context.getFrameSize()),
+      mIsInput(isInput(metadata)) {
     struct pcm_config config;
-    config.channels = usb::getChannelCountFromChannelMask(context.getChannelLayout(), isInput);
+    config.channels = usb::getChannelCountFromChannelMask(context.getChannelLayout(), mIsInput);
     if (config.channels == 0) {
         LOG(ERROR) << __func__ << ": invalid channel=" << context.getChannelLayout().toString();
         return;
@@ -63,48 +66,50 @@ DriverUsb::DriverUsb(const StreamContext& context, bool isInput)
     mConfig = config;
 }
 
-::android::status_t DriverUsb::init() {
+::android::status_t StreamUsb::init() {
     return mConfig.has_value() ? ::android::OK : ::android::NO_INIT;
 }
 
-::android::status_t DriverUsb::setConnectedDevices(
+const StreamCommonInterface::ConnectedDevices& StreamUsb::getConnectedDevices() const {
+    std::lock_guard guard(mLock);
+    return mConnectedDevices;
+}
+
+ndk::ScopedAStatus StreamUsb::setConnectedDevices(
         const std::vector<AudioDevice>& connectedDevices) {
     if (mIsInput && connectedDevices.size() > 1) {
         LOG(ERROR) << __func__ << ": wrong device size(" << connectedDevices.size()
                    << ") for input stream";
-        return ::android::BAD_VALUE;
+        return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
     }
     for (const auto& connectedDevice : connectedDevices) {
         if (connectedDevice.address.getTag() != AudioDeviceAddress::alsa) {
             LOG(ERROR) << __func__ << ": bad device address" << connectedDevice.address.toString();
-            return ::android::BAD_VALUE;
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
         }
     }
     std::lock_guard guard(mLock);
     mAlsaDeviceProxies.clear();
-    mConnectedDevices.clear();
-    for (const auto& connectedDevice : connectedDevices) {
-        mConnectedDevices.push_back(connectedDevice.address);
-    }
-    return ::android::OK;
+    RETURN_STATUS_IF_ERROR(StreamCommonImpl::setConnectedDevices(connectedDevices));
+    return ndk::ScopedAStatus::ok();
 }
 
-::android::status_t DriverUsb::drain(StreamDescriptor::DrainMode) {
+::android::status_t StreamUsb::drain(StreamDescriptor::DrainMode) {
     usleep(1000);
     return ::android::OK;
 }
 
-::android::status_t DriverUsb::flush() {
+::android::status_t StreamUsb::flush() {
     usleep(1000);
     return ::android::OK;
 }
 
-::android::status_t DriverUsb::pause() {
+::android::status_t StreamUsb::pause() {
     usleep(1000);
     return ::android::OK;
 }
 
-::android::status_t DriverUsb::transfer(void* buffer, size_t frameCount, size_t* actualFrameCount,
+::android::status_t StreamUsb::transfer(void* buffer, size_t frameCount, size_t* actualFrameCount,
                                         int32_t* latencyMs) {
     {
         std::lock_guard guard(mLock);
@@ -139,7 +144,7 @@ DriverUsb::DriverUsb(const StreamContext& context, bool isInput)
     return ::android::OK;
 }
 
-::android::status_t DriverUsb::standby() {
+::android::status_t StreamUsb::standby() {
     if (!mIsStandby) {
         std::lock_guard guard(mLock);
         mAlsaDeviceProxies.clear();
@@ -148,11 +153,15 @@ DriverUsb::DriverUsb(const StreamContext& context, bool isInput)
     return ::android::OK;
 }
 
-::android::status_t DriverUsb::exitStandby() {
+void StreamUsb::shutdown() {}
+
+::android::status_t StreamUsb::exitStandby() {
     std::vector<AudioDeviceAddress> connectedDevices;
     {
         std::lock_guard guard(mLock);
-        connectedDevices = mConnectedDevices;
+        std::transform(mConnectedDevices.begin(), mConnectedDevices.end(),
+                       std::back_inserter(connectedDevices),
+                       [](const auto& device) { return device.address; });
     }
     std::vector<std::shared_ptr<alsa_device_proxy>> alsaDeviceProxies;
     for (const auto& device : connectedDevices) {
@@ -196,32 +205,9 @@ DriverUsb::DriverUsb(const StreamContext& context, bool isInput)
     return ::android::OK;
 }
 
-// static
-ndk::ScopedAStatus StreamInUsb::createInstance(const SinkMetadata& sinkMetadata,
-                                               StreamContext&& context,
-                                               const std::vector<MicrophoneInfo>& microphones,
-                                               std::shared_ptr<StreamIn>* result) {
-    std::shared_ptr<StreamIn> stream =
-            ndk::SharedRefBase::make<StreamInUsb>(sinkMetadata, std::move(context), microphones);
-    if (auto status = initInstance(stream); !status.isOk()) {
-        return status;
-    }
-    *result = std::move(stream);
-    return ndk::ScopedAStatus::ok();
-}
-
 StreamInUsb::StreamInUsb(const SinkMetadata& sinkMetadata, StreamContext&& context,
                          const std::vector<MicrophoneInfo>& microphones)
-    : StreamIn(
-              sinkMetadata, std::move(context),
-              [](const StreamContext& ctx) -> DriverInterface* {
-                  return new DriverUsb(ctx, true /*isInput*/);
-              },
-              [](const StreamContext& ctx, DriverInterface* driver) -> StreamWorkerInterface* {
-                  // The default worker implementation is used.
-                  return new StreamInWorker(ctx, driver);
-              },
-              microphones) {}
+    : StreamUsb(sinkMetadata, std::move(context)), StreamIn(microphones) {}
 
 ndk::ScopedAStatus StreamInUsb::getActiveMicrophones(
         std::vector<MicrophoneDynamicInfo>* _aidl_return __unused) {
@@ -229,37 +215,10 @@ ndk::ScopedAStatus StreamInUsb::getActiveMicrophones(
     return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
 }
 
-// static
-ndk::ScopedAStatus StreamOutUsb::createInstance(const SourceMetadata& sourceMetadata,
-                                                StreamContext&& context,
-                                                const std::optional<AudioOffloadInfo>& offloadInfo,
-                                                std::shared_ptr<StreamOut>* result) {
-    if (offloadInfo.has_value()) {
-        LOG(ERROR) << __func__ << ": offload is not supported";
-        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
-    }
-    std::shared_ptr<StreamOut> stream =
-            ndk::SharedRefBase::make<StreamOutUsb>(sourceMetadata, std::move(context), offloadInfo);
-    if (auto status = initInstance(stream); !status.isOk()) {
-        return status;
-    }
-    *result = std::move(stream);
-    return ndk::ScopedAStatus::ok();
-}
-
 StreamOutUsb::StreamOutUsb(const SourceMetadata& sourceMetadata, StreamContext&& context,
                            const std::optional<AudioOffloadInfo>& offloadInfo)
-    : StreamOut(
-              sourceMetadata, std::move(context),
-              [](const StreamContext& ctx) -> DriverInterface* {
-                  return new DriverUsb(ctx, false /*isInput*/);
-              },
-              [](const StreamContext& ctx, DriverInterface* driver) -> StreamWorkerInterface* {
-                  // The default worker implementation is used.
-                  return new StreamOutWorker(ctx, driver);
-              },
-              offloadInfo) {
-    mChannelCount = getChannelCount(mContext.getChannelLayout());
+    : StreamUsb(sourceMetadata, std::move(context)), StreamOut(offloadInfo) {
+    mChannelCount = getChannelCount(getContext().getChannelLayout());
 }
 
 ndk::ScopedAStatus StreamOutUsb::getHwVolume(std::vector<float>* _aidl_return) {
@@ -268,7 +227,7 @@ ndk::ScopedAStatus StreamOutUsb::getHwVolume(std::vector<float>* _aidl_return) {
 }
 
 ndk::ScopedAStatus StreamOutUsb::setHwVolume(const std::vector<float>& in_channelVolumes) {
-    for (const auto& device : mConnectedDevices) {
+    for (const auto& device : getConnectedDevices()) {
         if (device.address.getTag() != AudioDeviceAddress::alsa) {
             LOG(DEBUG) << __func__ << ": skip as the device address is not alsa";
             continue;
diff --git a/audio/aidl/vts/VtsHalAudioCoreModuleTargetTest.cpp b/audio/aidl/vts/VtsHalAudioCoreModuleTargetTest.cpp
index 825b865ef1..0012cd559e 100644
--- a/audio/aidl/vts/VtsHalAudioCoreModuleTargetTest.cpp
+++ b/audio/aidl/vts/VtsHalAudioCoreModuleTargetTest.cpp
@@ -2763,6 +2763,7 @@ TEST_P(AudioStreamIn, ActiveMicrophones) {
             ASSERT_NO_FATAL_FAILURE(patch.SetUp(module.get()));
             std::vector<MicrophoneDynamicInfo> activeMics;
             EXPECT_IS_OK(stream.get()->getActiveMicrophones(&activeMics));
+            EXPECT_FALSE(activeMics.empty());
             for (const auto& mic : activeMics) {
                 EXPECT_NE(micInfos.end(),
                           std::find_if(micInfos.begin(), micInfos.end(),