diff --git a/audio/aidl/default/StreamSwitcher.cpp b/audio/aidl/default/StreamSwitcher.cpp
new file mode 100644
index 0000000..956f413
--- /dev/null
+++ b/audio/aidl/default/StreamSwitcher.cpp
@@ -0,0 +1,230 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <limits>
+
+#define LOG_TAG "AHAL_StreamSwitcher"
+
+#include <Utils.h>
+#include <android-base/logging.h>
+#include <error/expected_utils.h>
+
+#include "core-impl/StreamStub.h"
+#include "core-impl/StreamSwitcher.h"
+
+using aidl::android::hardware::audio::effect::IEffect;
+using aidl::android::media::audio::common::AudioDevice;
+
+namespace aidl::android::hardware::audio::core {
+
+StreamSwitcher::StreamSwitcher(StreamContext* context, const Metadata& metadata)
+    : mMetadata(metadata), mStream(new InnerStreamWrapper<StreamStub>(context, mMetadata)) {}
+
+ndk::ScopedAStatus StreamSwitcher::closeCurrentStream(bool validateStreamState) {
+    if (!mStream) return ndk::ScopedAStatus::ok();
+    RETURN_STATUS_IF_ERROR(mStream->prepareToClose());
+    RETURN_STATUS_IF_ERROR(mStream->close());
+    if (validateStreamState && !isValidClosingStreamState(mStream->getStatePriorToClosing())) {
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    mStream.reset();
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus StreamSwitcher::close() {
+    if (mStream != nullptr) {
+        auto status = closeCurrentStream(false /*validateStreamState*/);
+        // The actual state is irrelevant since only StreamSwitcher cares about it.
+        onClose(StreamDescriptor::State::STANDBY);
+        return status;
+    }
+    LOG(ERROR) << __func__ << ": stream was already closed";
+    return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+}
+
+ndk::ScopedAStatus StreamSwitcher::prepareToClose() {
+    if (mStream != nullptr) {
+        return mStream->prepareToClose();
+    }
+    LOG(ERROR) << __func__ << ": stream was closed";
+    return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+}
+
+ndk::ScopedAStatus StreamSwitcher::updateHwAvSyncId(int32_t in_hwAvSyncId) {
+    if (mStream == nullptr) {
+        LOG(ERROR) << __func__ << ": stream was closed";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    RETURN_STATUS_IF_ERROR(mStream->updateHwAvSyncId(in_hwAvSyncId));
+    mHwAvSyncId = in_hwAvSyncId;
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus StreamSwitcher::getVendorParameters(const std::vector<std::string>& in_ids,
+                                                       std::vector<VendorParameter>* _aidl_return) {
+    if (mStream == nullptr) {
+        LOG(ERROR) << __func__ << ": stream was closed";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    if (mIsStubStream) {
+        LOG(ERROR) << __func__ << ": the stream is not connected";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    return mStream->getVendorParameters(in_ids, _aidl_return);
+}
+
+ndk::ScopedAStatus StreamSwitcher::setVendorParameters(
+        const std::vector<VendorParameter>& in_parameters, bool in_async) {
+    if (mStream == nullptr) {
+        LOG(ERROR) << __func__ << ": stream was closed";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    if (mIsStubStream) {
+        mMissedParameters.emplace_back(in_parameters, in_async);
+        return ndk::ScopedAStatus::ok();
+    }
+    return mStream->setVendorParameters(in_parameters, in_async);
+}
+
+ndk::ScopedAStatus StreamSwitcher::addEffect(const std::shared_ptr<IEffect>& in_effect) {
+    if (mStream == nullptr) {
+        LOG(ERROR) << __func__ << ": stream was closed";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    if (!mIsStubStream) {
+        RETURN_STATUS_IF_ERROR(mStream->addEffect(in_effect));
+    }
+    mEffects.push_back(in_effect);
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus StreamSwitcher::removeEffect(const std::shared_ptr<IEffect>& in_effect) {
+    if (mStream == nullptr) {
+        LOG(ERROR) << __func__ << ": stream was closed";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    for (auto it = mEffects.begin(); it != mEffects.end();) {
+        if ((*it)->asBinder() == in_effect->asBinder()) {
+            it = mEffects.erase(it);
+        } else {
+            ++it;
+        }
+    }
+    return !mIsStubStream ? mStream->removeEffect(in_effect) : ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus StreamSwitcher::getStreamCommonCommon(
+        std::shared_ptr<IStreamCommon>* _aidl_return) {
+    if (!mCommon) {
+        LOG(FATAL) << __func__ << ": the common interface was not created";
+    }
+    *_aidl_return = mCommon.getInstance();
+    LOG(DEBUG) << __func__ << ": returning " << _aidl_return->get()->asBinder().get();
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus StreamSwitcher::updateMetadataCommon(const Metadata& metadata) {
+    if (mStream == nullptr) {
+        LOG(ERROR) << __func__ << ": stream was closed";
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_STATE);
+    }
+    mMetadata = metadata;
+    return !mIsStubStream ? mStream->updateMetadataCommon(metadata) : ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus StreamSwitcher::initInstance(
+        const std::shared_ptr<StreamCommonInterface>& delegate) {
+    mCommon = ndk::SharedRefBase::make<StreamCommonDelegator>(delegate);
+    // The delegate is null because StreamSwitcher handles IStreamCommon methods by itself.
+    return mStream->initInstance(nullptr);
+}
+
+const StreamContext& StreamSwitcher::getContext() const {
+    return *mContext;
+}
+
+bool StreamSwitcher::isClosed() const {
+    return mStream == nullptr || mStream->isClosed();
+}
+
+const StreamCommonInterface::ConnectedDevices& StreamSwitcher::getConnectedDevices() const {
+    return mStream->getConnectedDevices();
+}
+
+ndk::ScopedAStatus StreamSwitcher::setConnectedDevices(const std::vector<AudioDevice>& devices) {
+    LOG(DEBUG) << __func__ << ": " << ::android::internal::ToString(devices);
+    if (mStream->getConnectedDevices() == devices) return ndk::ScopedAStatus::ok();
+    const DeviceSwitchBehavior behavior = switchCurrentStream(devices);
+    if (behavior == DeviceSwitchBehavior::UNSUPPORTED_DEVICES) {
+        return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
+    } else if (behavior == DeviceSwitchBehavior::SWITCH_TO_STUB_STREAM && !devices.empty()) {
+        // This is an error in the extending class.
+        LOG(FATAL) << __func__
+                   << ": switching to stub stream with connected devices is not allowed";
+    }
+    if (behavior == USE_CURRENT_STREAM) {
+        mIsStubStream = false;
+    } else {
+        LOG(DEBUG) << __func__ << ": connected devices changed, switching stream";
+        // Two streams can't be opened for the same context, thus we always need to close
+        // the current one before creating a new one.
+        RETURN_STATUS_IF_ERROR(closeCurrentStream(true /*validateStreamState*/));
+        if (behavior == CREATE_NEW_STREAM) {
+            mStream = createNewStream(devices, mContext, mMetadata);
+            mIsStubStream = false;
+        } else {  // SWITCH_TO_STUB_STREAM
+            mStream.reset(new InnerStreamWrapper<StreamStub>(mContext, mMetadata));
+            mIsStubStream = true;
+        }
+        // The delegate is null because StreamSwitcher handles IStreamCommon methods by itself.
+        if (ndk::ScopedAStatus status = mStream->initInstance(nullptr); !status.isOk()) {
+            // Need to close the current failed stream, and report an error.
+            // Since we can't operate without a stream implementation, put a stub in.
+            RETURN_STATUS_IF_ERROR(closeCurrentStream(false /*validateStreamState*/));
+            mStream.reset(new InnerStreamWrapper<StreamStub>(mContext, mMetadata));
+            (void)mStream->initInstance(nullptr);
+            (void)mStream->setConnectedDevices(devices);
+            return status;
+        }
+    }
+    RETURN_STATUS_IF_ERROR(mStream->setConnectedDevices(devices));
+    if (behavior == CREATE_NEW_STREAM) {
+        // These updates are less critical, only log warning on failure.
+        if (mHwAvSyncId.has_value()) {
+            if (auto status = mStream->updateHwAvSyncId(*mHwAvSyncId); !status.isOk()) {
+                LOG(WARNING) << __func__ << ": could not update HW AV Sync for a new stream: "
+                             << status.getDescription();
+            }
+        }
+        for (const auto& vndParam : mMissedParameters) {
+            if (auto status = mStream->setVendorParameters(vndParam.first, vndParam.second);
+                !status.isOk()) {
+                LOG(WARNING) << __func__ << ": error while setting parameters for a new stream: "
+                             << status.getDescription();
+            }
+        }
+        mMissedParameters.clear();
+        for (const auto& effect : mEffects) {
+            if (auto status = mStream->addEffect(effect); !status.isOk()) {
+                LOG(WARNING) << __func__ << ": error while adding effect for a new stream: "
+                             << status.getDescription();
+            }
+        }
+    }
+    return ndk::ScopedAStatus::ok();
+}
+
+}  // namespace aidl::android::hardware::audio::core