diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 94a90b7..7a5cf66 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -3039,8 +3039,8 @@
 
     if (status == NO_ERROR) {
         if (flags & AUDIO_OUTPUT_FLAG_MMAP_NOIRQ) {
-            const sp<IAfMmapPlaybackThread> thread =
-                    new MmapPlaybackThread(this, *output, outHwDev, outputStream, mSystemReady);
+            const sp<IAfMmapPlaybackThread> thread = IAfMmapPlaybackThread::create(
+                    this, *output, outHwDev, outputStream, mSystemReady);
             mMmapThreads.add(*output, thread);
             ALOGV("openOutput_l() created mmap playback thread: ID %d thread %p",
                   *output, thread.get());
@@ -3048,28 +3048,30 @@
         } else {
             sp<IAfPlaybackThread> thread;
             if (flags & AUDIO_OUTPUT_FLAG_BIT_PERFECT) {
-                thread = sp<BitPerfectThread>::make(this, outputStream, *output, mSystemReady);
+                thread = IAfPlaybackThread::createBitPerfectThread(
+                        this, outputStream, *output, mSystemReady);
                 ALOGV("%s() created bit-perfect output: ID %d thread %p",
                       __func__, *output, thread.get());
             } else if (flags & AUDIO_OUTPUT_FLAG_SPATIALIZER) {
-                thread = new SpatializerThread(this, outputStream, *output,
+                thread = IAfPlaybackThread::createSpatializerThread(this, outputStream, *output,
                                                     mSystemReady, mixerConfig);
                 ALOGV("openOutput_l() created spatializer output: ID %d thread %p",
                       *output, thread.get());
             } else if (flags & AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD) {
-                thread = new OffloadThread(this, outputStream, *output,
+                thread = IAfPlaybackThread::createOffloadThread(this, outputStream, *output,
                         mSystemReady, halConfig->offload_info);
                 ALOGV("openOutput_l() created offload output: ID %d thread %p",
                       *output, thread.get());
             } else if ((flags & AUDIO_OUTPUT_FLAG_DIRECT)
                     || !isValidPcmSinkFormat(halConfig->format)
                     || !isValidPcmSinkChannelMask(halConfig->channel_mask)) {
-                thread = new DirectOutputThread(this, outputStream, *output,
+                thread = IAfPlaybackThread::createDirectOutputThread(this, outputStream, *output,
                         mSystemReady, halConfig->offload_info);
                 ALOGV("openOutput_l() created direct output: ID %d thread %p",
                       *output, thread.get());
             } else {
-                thread = new MixerThread(this, outputStream, *output, mSystemReady);
+                thread = IAfPlaybackThread::createMixerThread(
+                        this, outputStream, *output, mSystemReady);
                 ALOGV("openOutput_l() created mixer output: ID %d thread %p",
                       *output, thread.get());
             }
@@ -3172,7 +3174,8 @@
     }
 
     audio_io_handle_t id = nextUniqueId(AUDIO_UNIQUE_ID_USE_OUTPUT);
-    IAfDuplicatingThread* const thread = new DuplicatingThread(this, thread1, id, mSystemReady);
+    const sp<IAfDuplicatingThread> thread = IAfDuplicatingThread::create(
+            this, thread1, id, mSystemReady);
     thread->addOutputTrack(thread2);
     mPlaybackThreads.add(id, thread);
     // notify client processes of the new output creation
@@ -3411,7 +3414,7 @@
         AudioStreamIn *inputStream = new AudioStreamIn(inHwDev, inStream, flags);
         if ((flags & AUDIO_INPUT_FLAG_MMAP_NOIRQ) != 0) {
             const sp<IAfMmapCaptureThread> thread =
-                    new MmapCaptureThread(this, *input, inHwDev, inputStream, mSystemReady);
+                    IAfMmapCaptureThread::create(this, *input, inHwDev, inputStream, mSystemReady);
             mMmapThreads.add(*input, thread);
             ALOGV("openInput_l() created mmap capture thread: ID %d thread %p", *input,
                     thread.get());
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 19fed25..7067c83 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -150,10 +150,24 @@
 
 using android::content::AttributionSourceState;
 
+struct stream_type_t {
+    float volume = 1.f;
+    bool mute = false;
+};
+
 class AudioFlinger : public AudioFlingerServerAdapter::Delegate
 {
     friend class sp<AudioFlinger>;
     friend class Client; // removeClient_l();
+    // TODO(b/291012167) replace the Thread friends with an interface.
+    friend class DirectOutputThread;
+    friend class MixerThread;
+    friend class MmapPlaybackThread;
+    friend class MmapThread;
+    friend class PlaybackThread;
+    friend class RecordThread;
+    friend class ThreadBase;
+
 public:
     static void instantiate() ANDROID_API;
 
@@ -571,20 +585,6 @@
     using TeePatches = std::vector<TeePatch>;
 private:
 
-    struct  stream_type_t {
-        stream_type_t()
-            :   volume(1.0f),
-                mute(false)
-        {
-        }
-        float       volume;
-        bool        mute;
-    };
-
-    // --- PlaybackThread ---
-
-#include "Threads.h"
-
 #include "PatchPanel.h"
 
 #include "PatchCommandThread.h"
diff --git a/services/audioflinger/IAfEffect.h b/services/audioflinger/IAfEffect.h
index c6cb3c9..c024ef7 100644
--- a/services/audioflinger/IAfEffect.h
+++ b/services/audioflinger/IAfEffect.h
@@ -367,4 +367,4 @@
     virtual status_t removeEffectFromHal(const sp<EffectHalInterface>& effect) = 0;
 };
 
-} // namespace android
+}  // namespace android
diff --git a/services/audioflinger/IAfThread.h b/services/audioflinger/IAfThread.h
index 0a51b7e..8b87ed7 100644
--- a/services/audioflinger/IAfThread.h
+++ b/services/audioflinger/IAfThread.h
@@ -255,6 +255,26 @@
 
 class IAfPlaybackThread : public virtual IAfThreadBase, public virtual VolumeInterface {
 public:
+    static sp<IAfPlaybackThread> createBitPerfectThread(
+            const sp<AudioFlinger>& audioflinger, AudioStreamOut* output, audio_io_handle_t id,
+            bool systemReady);
+
+    static sp<IAfPlaybackThread> createDirectOutputThread(
+            const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output, audio_io_handle_t id,
+            bool systemReady, const audio_offload_info_t& offloadInfo);
+
+    static sp<IAfPlaybackThread> createMixerThread(
+            const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output, audio_io_handle_t id,
+            bool systemReady, type_t type = MIXER, audio_config_base_t* mixerConfig = nullptr);
+
+    static sp<IAfPlaybackThread> createOffloadThread(
+            const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output, audio_io_handle_t id,
+            bool systemReady, const audio_offload_info_t& offloadInfo);
+
+    static sp<IAfPlaybackThread> createSpatializerThread(
+            const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output, audio_io_handle_t id,
+            bool systemReady, audio_config_base_t* mixerConfig);
+
     static constexpr int8_t kMaxTrackStopRetriesOffload = 2;
 
     enum mixer_state {
@@ -367,6 +387,10 @@
 
 class IAfDuplicatingThread : public virtual IAfPlaybackThread {
 public:
+    static sp<IAfDuplicatingThread> create(
+            const sp<AudioFlinger>& audioFlinger, IAfPlaybackThread* mainThread,
+            audio_io_handle_t id, bool systemReady);
+
     virtual void addOutputTrack(IAfPlaybackThread* thread) = 0;
     virtual uint32_t waitTimeMs() const = 0;
     virtual void removeOutputTrack(IAfPlaybackThread* thread) = 0;
@@ -474,11 +498,19 @@
 
 class IAfMmapPlaybackThread : public virtual IAfMmapThread, public virtual VolumeInterface {
 public:
+    static sp<IAfMmapPlaybackThread> create(
+            const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id, AudioHwDevice* hwDev,
+            AudioStreamOut* output, bool systemReady);
+
     virtual AudioStreamOut* clearOutput() = 0;
 };
 
 class IAfMmapCaptureThread : public virtual IAfMmapThread {
 public:
+    static sp<IAfMmapCaptureThread> create(
+            const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id, AudioHwDevice* hwDev,
+            AudioStreamIn* input, bool systemReady);
+
     virtual AudioStreamIn* clearInput() = 0;
 };
 
diff --git a/services/audioflinger/MmapTracks.h b/services/audioflinger/MmapTracks.h
index 0cee3f8..16c141f 100644
--- a/services/audioflinger/MmapTracks.h
+++ b/services/audioflinger/MmapTracks.h
@@ -60,7 +60,7 @@
      */
     void processMuteEvent_l(const sp<IAudioManager>& audioManager,
                             mute_state_t muteState)
-                            REQUIRES(AudioFlinger::MmapPlaybackThread::mLock) final;
+                            /* REQUIRES(MmapPlaybackThread::mLock) */ final;
 private:
     friend class MmapThread;
 
@@ -82,9 +82,9 @@
     // TODO: replace PersistableBundle with own struct
     // access these two variables only when holding player thread lock.
     std::unique_ptr<os::PersistableBundle> mMuteEventExtras
-            GUARDED_BY(AudioFlinger::MmapPlaybackThread::mLock);
+            /* GUARDED_BY(MmapPlaybackThread::mLock) */;
     mute_state_t mMuteState
-            GUARDED_BY(AudioFlinger::MmapPlaybackThread::mLock);
+            /* GUARDED_BY(MmapPlaybackThread::mLock) */;
 };  // end of Track
 
 } // namespace android
\ No newline at end of file
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index ab4014e..76c9169 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -76,6 +76,8 @@
 #include <media/audiohal/StreamHalInterface.h>
 
 #include "AudioFlinger.h"
+#include "Threads.h"
+
 #include <mediautils/SchedulingPolicyService.h>
 #include <mediautils/ServiceUtilities.h>
 
@@ -120,6 +122,7 @@
 
 namespace android {
 
+using audioflinger::SyncEvent;
 using media::IEffectClient;
 using content::AttributionSourceState;
 
@@ -515,7 +518,7 @@
 // ----------------------------------------------------------------------------
 
 // static
-const char *AudioFlinger::ThreadBase::threadTypeToString(AudioFlinger::ThreadBase::type_t type)
+const char* ThreadBase::threadTypeToString(ThreadBase::type_t type)
 {
     switch (type) {
     case MIXER:
@@ -541,7 +544,7 @@
     }
 }
 
-AudioFlinger::ThreadBase::ThreadBase(const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id,
+ThreadBase::ThreadBase(const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id,
         type_t type, bool systemReady, bool isOut)
     :   Thread(false /*canCallJava*/),
         mType(type),
@@ -564,7 +567,7 @@
     memset(&mPatch, 0, sizeof(struct audio_patch));
 }
 
-AudioFlinger::ThreadBase::~ThreadBase()
+ThreadBase::~ThreadBase()
 {
     // mConfigEvents should be empty, but just in case it isn't, free the memory it owns
     mConfigEvents.clear();
@@ -579,7 +582,7 @@
     sendStatistics(true /* force */);
 }
 
-status_t AudioFlinger::ThreadBase::readyToRun()
+status_t ThreadBase::readyToRun()
 {
     status_t status = initCheck();
     if (status == NO_ERROR) {
@@ -590,7 +593,7 @@
     return status;
 }
 
-void AudioFlinger::ThreadBase::exit()
+void ThreadBase::exit()
 {
     ALOGV("ThreadBase::exit");
     // do any cleanup required for exit to succeed
@@ -614,7 +617,7 @@
     requestExitAndWait();
 }
 
-status_t AudioFlinger::ThreadBase::setParameters(const String8& keyValuePairs)
+status_t ThreadBase::setParameters(const String8& keyValuePairs)
 {
     ALOGV("ThreadBase::setParameters() %s", keyValuePairs.string());
     Mutex::Autolock _l(mLock);
@@ -624,7 +627,7 @@
 
 // sendConfigEvent_l() must be called with ThreadBase::mLock held
 // Can temporarily release the lock if waiting for a reply from processConfigEvents_l().
-status_t AudioFlinger::ThreadBase::sendConfigEvent_l(sp<ConfigEvent>& event)
+status_t ThreadBase::sendConfigEvent_l(sp<ConfigEvent>& event)
 NO_THREAD_SAFETY_ANALYSIS  // condition variable
 {
     status_t status = NO_ERROR;
@@ -652,7 +655,7 @@
     return status;
 }
 
-void AudioFlinger::ThreadBase::sendIoConfigEvent(audio_io_config_event_t event, pid_t pid,
+void ThreadBase::sendIoConfigEvent(audio_io_config_event_t event, pid_t pid,
                                                  audio_port_handle_t portId)
 {
     Mutex::Autolock _l(mLock);
@@ -660,7 +663,7 @@
 }
 
 // sendIoConfigEvent_l() must be called with ThreadBase::mLock held
-void AudioFlinger::ThreadBase::sendIoConfigEvent_l(audio_io_config_event_t event, pid_t pid,
+void ThreadBase::sendIoConfigEvent_l(audio_io_config_event_t event, pid_t pid,
                                                    audio_port_handle_t portId)
 {
     // The audio statistics history is exponentially weighted to forget events
@@ -677,14 +680,14 @@
     sendConfigEvent_l(configEvent);
 }
 
-void AudioFlinger::ThreadBase::sendPrioConfigEvent(pid_t pid, pid_t tid, int32_t prio, bool forApp)
+void ThreadBase::sendPrioConfigEvent(pid_t pid, pid_t tid, int32_t prio, bool forApp)
 {
     Mutex::Autolock _l(mLock);
     sendPrioConfigEvent_l(pid, tid, prio, forApp);
 }
 
 // sendPrioConfigEvent_l() must be called with ThreadBase::mLock held
-void AudioFlinger::ThreadBase::sendPrioConfigEvent_l(
+void ThreadBase::sendPrioConfigEvent_l(
         pid_t pid, pid_t tid, int32_t prio, bool forApp)
 {
     sp<ConfigEvent> configEvent = (ConfigEvent *)new PrioConfigEvent(pid, tid, prio, forApp);
@@ -692,7 +695,7 @@
 }
 
 // sendSetParameterConfigEvent_l() must be called with ThreadBase::mLock held
-status_t AudioFlinger::ThreadBase::sendSetParameterConfigEvent_l(const String8& keyValuePair)
+status_t ThreadBase::sendSetParameterConfigEvent_l(const String8& keyValuePair)
 {
     sp<ConfigEvent> configEvent;
     AudioParameter param(keyValuePair);
@@ -710,7 +713,7 @@
     return sendConfigEvent_l(configEvent);
 }
 
-status_t AudioFlinger::ThreadBase::sendCreateAudioPatchConfigEvent(
+status_t ThreadBase::sendCreateAudioPatchConfigEvent(
                                                         const struct audio_patch *patch,
                                                         audio_patch_handle_t *handle)
 {
@@ -725,7 +728,7 @@
     return status;
 }
 
-status_t AudioFlinger::ThreadBase::sendReleaseAudioPatchConfigEvent(
+status_t ThreadBase::sendReleaseAudioPatchConfigEvent(
                                                                 const audio_patch_handle_t handle)
 {
     Mutex::Autolock _l(mLock);
@@ -733,7 +736,7 @@
     return sendConfigEvent_l(configEvent);
 }
 
-status_t AudioFlinger::ThreadBase::sendUpdateOutDeviceConfigEvent(
+status_t ThreadBase::sendUpdateOutDeviceConfigEvent(
         const DeviceDescriptorBaseVector& outDevices)
 {
     if (type() != RECORD) {
@@ -745,7 +748,7 @@
     return sendConfigEvent_l(configEvent);
 }
 
-void AudioFlinger::ThreadBase::sendResizeBufferConfigEvent_l(int32_t maxSharedAudioHistoryMs)
+void ThreadBase::sendResizeBufferConfigEvent_l(int32_t maxSharedAudioHistoryMs)
 {
     ALOG_ASSERT(type() == RECORD, "sendResizeBufferConfigEvent_l() called on non record thread");
     sp<ConfigEvent> configEvent =
@@ -753,27 +756,27 @@
     sendConfigEvent_l(configEvent);
 }
 
-void AudioFlinger::ThreadBase::sendCheckOutputStageEffectsEvent()
+void ThreadBase::sendCheckOutputStageEffectsEvent()
 {
     Mutex::Autolock _l(mLock);
     sendCheckOutputStageEffectsEvent_l();
 }
 
-void AudioFlinger::ThreadBase::sendCheckOutputStageEffectsEvent_l()
+void ThreadBase::sendCheckOutputStageEffectsEvent_l()
 {
     sp<ConfigEvent> configEvent =
             (ConfigEvent *)new CheckOutputStageEffectsEvent();
     sendConfigEvent_l(configEvent);
 }
 
-void AudioFlinger::ThreadBase::sendHalLatencyModesChangedEvent_l()
+void ThreadBase::sendHalLatencyModesChangedEvent_l()
 {
     sp<ConfigEvent> configEvent = sp<HalLatencyModesChangedEvent>::make();
     sendConfigEvent_l(configEvent);
 }
 
 // post condition: mConfigEvents.isEmpty()
-void AudioFlinger::ThreadBase::processConfigEvents_l()
+void ThreadBase::processConfigEvents_l()
 {
     bool configChanged = false;
 
@@ -940,7 +943,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::dump(int fd, const Vector<String16>& args)
+void ThreadBase::dump(int fd, const Vector<String16>& args)
 NO_THREAD_SAFETY_ANALYSIS  // conditional try lock
 {
     dprintf(fd, "\n%s thread %p, name %s, tid %d, type %d (%s):\n", isOutput() ? "Output" : "Input",
@@ -978,7 +981,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::dumpBase_l(int fd, const Vector<String16>& args __unused)
+void ThreadBase::dumpBase_l(int fd, const Vector<String16>& /* args */)
 {
     dprintf(fd, "  I/O handle: %d\n", mId);
     dprintf(fd, "  Standby: %s\n", mStandby ? "yes" : "no");
@@ -1051,7 +1054,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::dumpEffectChains_l(int fd, const Vector<String16>& args)
+void ThreadBase::dumpEffectChains_l(int fd, const Vector<String16>& args)
 {
     const size_t SIZE = 256;
     char buffer[SIZE];
@@ -1068,13 +1071,13 @@
     }
 }
 
-void AudioFlinger::ThreadBase::acquireWakeLock()
+void ThreadBase::acquireWakeLock()
 {
     Mutex::Autolock _l(mLock);
     acquireWakeLock_l();
 }
 
-String16 AudioFlinger::ThreadBase::getWakeLockTag()
+String16 ThreadBase::getWakeLockTag()
 {
     switch (mType) {
     case MIXER:
@@ -1099,7 +1102,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::acquireWakeLock_l()
+void ThreadBase::acquireWakeLock_l()
 {
     getPowerManager_l();
     if (mPowerManager != 0) {
@@ -1122,13 +1125,13 @@
             gBoottime.getBoottimeOffset();
 }
 
-void AudioFlinger::ThreadBase::releaseWakeLock()
+void ThreadBase::releaseWakeLock()
 {
     Mutex::Autolock _l(mLock);
     releaseWakeLock_l();
 }
 
-void AudioFlinger::ThreadBase::releaseWakeLock_l()
+void ThreadBase::releaseWakeLock_l()
 {
     gBoottime.release(mWakeLockToken);
     if (mWakeLockToken != 0) {
@@ -1140,7 +1143,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::getPowerManager_l() {
+void ThreadBase::getPowerManager_l() {
     if (mSystemReady && mPowerManager == 0) {
         // use checkService() to avoid blocking if power service is not up yet
         sp<IBinder> binder =
@@ -1154,7 +1157,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::updateWakeLockUids_l(const SortedVector<uid_t> &uids) {
+void ThreadBase::updateWakeLockUids_l(const SortedVector<uid_t>& uids) {
     getPowerManager_l();
 
 #if !LOG_NDEBUG
@@ -1181,25 +1184,25 @@
     }
 }
 
-void AudioFlinger::ThreadBase::clearPowerManager()
+void ThreadBase::clearPowerManager()
 {
     Mutex::Autolock _l(mLock);
     releaseWakeLock_l();
     mPowerManager.clear();
 }
 
-void AudioFlinger::ThreadBase::updateOutDevices(
+void ThreadBase::updateOutDevices(
         const DeviceDescriptorBaseVector& outDevices __unused)
 {
     ALOGE("%s should only be called in RecordThread", __func__);
 }
 
-void AudioFlinger::ThreadBase::resizeInputBuffer_l(int32_t maxSharedAudioHistoryMs __unused)
+void ThreadBase::resizeInputBuffer_l(int32_t /* maxSharedAudioHistoryMs */)
 {
     ALOGE("%s should only be called in RecordThread", __func__);
 }
 
-void AudioFlinger::ThreadBase::PMDeathRecipient::binderDied(const wp<IBinder>& who __unused)
+void ThreadBase::PMDeathRecipient::binderDied(const wp<IBinder>& /* who */)
 {
     sp<ThreadBase> thread = mThread.promote();
     if (thread != 0) {
@@ -1208,7 +1211,7 @@
     ALOGW("power manager service died !!!");
 }
 
-void AudioFlinger::ThreadBase::setEffectSuspended_l(
+void ThreadBase::setEffectSuspended_l(
         const effect_uuid_t *type, bool suspend, audio_session_t sessionId)
 {
     sp<IAfEffectChain> chain = getEffectChain_l(sessionId);
@@ -1223,7 +1226,7 @@
     updateSuspendedSessions_l(type, suspend, sessionId);
 }
 
-void AudioFlinger::ThreadBase::checkSuspendOnAddEffectChain_l(const sp<IAfEffectChain>& chain)
+void ThreadBase::checkSuspendOnAddEffectChain_l(const sp<IAfEffectChain>& chain)
 {
     ssize_t index = mSuspendedSessions.indexOfKey(chain->sessionId());
     if (index < 0) {
@@ -1247,7 +1250,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::updateSuspendedSessions_l(const effect_uuid_t *type,
+void ThreadBase::updateSuspendedSessions_l(const effect_uuid_t* type,
                                                          bool suspend,
                                                          audio_session_t sessionId)
 {
@@ -1308,7 +1311,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::checkSuspendOnEffectEnabled(bool enabled,
+void ThreadBase::checkSuspendOnEffectEnabled(bool enabled,
                                                            audio_session_t sessionId,
                                                            bool threadLocked)
 NO_THREAD_SAFETY_ANALYSIS  // manual locking
@@ -1334,7 +1337,7 @@
 }
 
 // checkEffectCompatibility_l() must be called with ThreadBase::mLock held
-status_t AudioFlinger::RecordThread::checkEffectCompatibility_l(
+status_t RecordThread::checkEffectCompatibility_l(
         const effect_descriptor_t *desc, audio_session_t sessionId)
 {
     // No global output effect sessions on record threads
@@ -1378,7 +1381,7 @@
 }
 
 // checkEffectCompatibility_l() must be called with ThreadBase::mLock held
-status_t AudioFlinger::PlaybackThread::checkEffectCompatibility_l(
+status_t PlaybackThread::checkEffectCompatibility_l(
         const effect_descriptor_t *desc, audio_session_t sessionId)
 {
     // no preprocessing on playback threads
@@ -1533,7 +1536,7 @@
 }
 
 // ThreadBase::createEffect_l() must be called with AudioFlinger::mLock held
-sp<IAfEffectHandle> AudioFlinger::ThreadBase::createEffect_l(
+sp<IAfEffectHandle> ThreadBase::createEffect_l(
         const sp<Client>& client,
         const sp<IEffectClient>& effectClient,
         int32_t priority,
@@ -1638,7 +1641,7 @@
     return handle;
 }
 
-void AudioFlinger::ThreadBase::disconnectEffectHandle(IAfEffectHandle *handle,
+void ThreadBase::disconnectEffectHandle(IAfEffectHandle* handle,
                                                       bool unpinIfLast)
 {
     bool remove = false;
@@ -1668,7 +1671,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::onEffectEnable(const sp<IAfEffectModule>& effect) {
+void ThreadBase::onEffectEnable(const sp<IAfEffectModule>& effect) {
     if (isOffloadOrMmap()) {
         Mutex::Autolock _l(mLock);
         broadcast_l();
@@ -1684,28 +1687,28 @@
     }
 }
 
-void AudioFlinger::ThreadBase::onEffectDisable() {
+void ThreadBase::onEffectDisable() {
     if (isOffloadOrMmap()) {
         Mutex::Autolock _l(mLock);
         broadcast_l();
     }
 }
 
-sp<IAfEffectModule> AudioFlinger::ThreadBase::getEffect(audio_session_t sessionId,
+sp<IAfEffectModule> ThreadBase::getEffect(audio_session_t sessionId,
         int effectId) const
 {
     Mutex::Autolock _l(mLock);
     return getEffect_l(sessionId, effectId);
 }
 
-sp<IAfEffectModule> AudioFlinger::ThreadBase::getEffect_l(audio_session_t sessionId,
+sp<IAfEffectModule> ThreadBase::getEffect_l(audio_session_t sessionId,
         int effectId) const
 {
     sp<IAfEffectChain> chain = getEffectChain_l(sessionId);
     return chain != 0 ? chain->getEffectFromId_l(effectId) : 0;
 }
 
-std::vector<int> AudioFlinger::ThreadBase::getEffectIds_l(audio_session_t sessionId) const
+std::vector<int> ThreadBase::getEffectIds_l(audio_session_t sessionId) const
 {
     sp<IAfEffectChain> chain = getEffectChain_l(sessionId);
     return chain != nullptr ? chain->getEffectIds() : std::vector<int>{};
@@ -1713,7 +1716,7 @@
 
 // PlaybackThread::addEffect_l() must be called with AudioFlinger::mLock and
 // PlaybackThread::mLock held
-status_t AudioFlinger::ThreadBase::addEffect_l(const sp<IAfEffectModule>& effect)
+status_t ThreadBase::addEffect_l(const sp<IAfEffectModule>& effect)
 {
     // check for existing effect chain with the requested audio session
     audio_session_t sessionId = effect->sessionId();
@@ -1758,7 +1761,7 @@
     return NO_ERROR;
 }
 
-void AudioFlinger::ThreadBase::removeEffect_l(const sp<IAfEffectModule>& effect, bool release) {
+void ThreadBase::removeEffect_l(const sp<IAfEffectModule>& effect, bool release) {
 
     ALOGV("%s %p effect %p", __FUNCTION__, this, effect.get());
     effect_descriptor_t desc = effect->desc();
@@ -1777,7 +1780,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::lockEffectChains_l(
+void ThreadBase::lockEffectChains_l(
         Vector<sp<IAfEffectChain>>& effectChains)
 NO_THREAD_SAFETY_ANALYSIS  // calls EffectChain::lock()
 {
@@ -1787,7 +1790,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::unlockEffectChains(
+void ThreadBase::unlockEffectChains(
         const Vector<sp<IAfEffectChain>>& effectChains)
 NO_THREAD_SAFETY_ANALYSIS  // calls EffectChain::unlock()
 {
@@ -1796,13 +1799,13 @@
     }
 }
 
-sp<IAfEffectChain> AudioFlinger::ThreadBase::getEffectChain(audio_session_t sessionId) const
+sp<IAfEffectChain> ThreadBase::getEffectChain(audio_session_t sessionId) const
 {
     Mutex::Autolock _l(mLock);
     return getEffectChain_l(sessionId);
 }
 
-sp<IAfEffectChain> AudioFlinger::ThreadBase::getEffectChain_l(audio_session_t sessionId)
+sp<IAfEffectChain> ThreadBase::getEffectChain_l(audio_session_t sessionId)
         const
 {
     size_t size = mEffectChains.size();
@@ -1814,7 +1817,7 @@
     return 0;
 }
 
-void AudioFlinger::ThreadBase::setMode(audio_mode_t mode)
+void ThreadBase::setMode(audio_mode_t mode)
 {
     Mutex::Autolock _l(mLock);
     size_t size = mEffectChains.size();
@@ -1823,7 +1826,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::toAudioPortConfig(struct audio_port_config *config)
+void ThreadBase::toAudioPortConfig(struct audio_port_config* config)
 {
     config->type = AUDIO_PORT_TYPE_MIX;
     config->ext.mix.handle = mId;
@@ -1834,7 +1837,7 @@
                             AUDIO_PORT_CONFIG_FORMAT;
 }
 
-void AudioFlinger::ThreadBase::systemReady()
+void ThreadBase::systemReady()
 {
     Mutex::Autolock _l(mLock);
     if (mSystemReady) {
@@ -1849,7 +1852,7 @@
 }
 
 template <typename T>
-ssize_t AudioFlinger::ThreadBase::ActiveTracks<T>::add(const sp<T> &track) {
+ssize_t ThreadBase::ActiveTracks<T>::add(const sp<T>& track) {
     ssize_t index = mActiveTracks.indexOf(track);
     if (index >= 0) {
         ALOGW("ActiveTracks<T>::add track %p already there", track.get());
@@ -1864,7 +1867,7 @@
 }
 
 template <typename T>
-ssize_t AudioFlinger::ThreadBase::ActiveTracks<T>::remove(const sp<T> &track) {
+ssize_t ThreadBase::ActiveTracks<T>::remove(const sp<T>& track) {
     ssize_t index = mActiveTracks.remove(track);
     if (index < 0) {
         ALOGW("ActiveTracks<T>::remove nonexistent track %p", track.get());
@@ -1883,7 +1886,7 @@
 }
 
 template <typename T>
-void AudioFlinger::ThreadBase::ActiveTracks<T>::clear() {
+void ThreadBase::ActiveTracks<T>::clear() {
     for (const sp<T> &track : mActiveTracks) {
         track->endBatteryAttribution();
         logTrack("clear", track);
@@ -1895,7 +1898,7 @@
 }
 
 template <typename T>
-void AudioFlinger::ThreadBase::ActiveTracks<T>::updatePowerState(
+void ThreadBase::ActiveTracks<T>::updatePowerState(
         const sp<ThreadBase>& thread, bool force) {
     // Updates ActiveTracks client uids to the thread wakelock.
     if (mActiveTracksGeneration != mLastActiveTracksGeneration || force) {
@@ -1905,7 +1908,7 @@
 }
 
 template <typename T>
-bool AudioFlinger::ThreadBase::ActiveTracks<T>::readAndClearHasChanged() {
+bool ThreadBase::ActiveTracks<T>::readAndClearHasChanged() {
     bool hasChanged = mHasChanged;
     mHasChanged = false;
 
@@ -1918,7 +1921,7 @@
 }
 
 template <typename T>
-void AudioFlinger::ThreadBase::ActiveTracks<T>::logTrack(
+void ThreadBase::ActiveTracks<T>::logTrack(
         const char *funcName, const sp<T> &track) const {
     if (mLocalLog != nullptr) {
         String8 result;
@@ -1927,7 +1930,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::broadcast_l()
+void ThreadBase::broadcast_l()
 {
     // Thread could be blocked waiting for async
     // so signal it to handle state changes immediately
@@ -1939,7 +1942,7 @@
 
 // Call only from threadLoop() or when it is idle.
 // Do not call from high performance code as this may do binder rpc to the MediaMetrics service.
-void AudioFlinger::ThreadBase::sendStatistics(bool force)
+void ThreadBase::sendStatistics(bool force)
 {
     // Do not log if we have no stats.
     // We choose the timestamp verifier because it is the most likely item to be present.
@@ -2002,7 +2005,7 @@
     item->selfrecord();
 }
 
-product_strategy_t AudioFlinger::ThreadBase::getStrategyForStream(audio_stream_type_t stream) const
+product_strategy_t ThreadBase::getStrategyForStream(audio_stream_type_t stream) const
 {
     if (!mAudioFlinger->isAudioPolicyReady()) {
         return PRODUCT_STRATEGY_NONE;
@@ -2011,7 +2014,7 @@
 }
 
 // startMelComputation_l() must be called with AudioFlinger::mLock held
-void AudioFlinger::ThreadBase::startMelComputation_l(
+void ThreadBase::startMelComputation_l(
         const sp<audio_utils::MelProcessor>& /*processor*/)
 {
     // Do nothing
@@ -2019,7 +2022,7 @@
 }
 
 // stopMelComputation_l() must be called with AudioFlinger::mLock held
-void AudioFlinger::ThreadBase::stopMelComputation_l()
+void ThreadBase::stopMelComputation_l()
 {
     // Do nothing
     ALOGW("%s: ThreadBase does not support CSD", __func__);
@@ -2029,7 +2032,7 @@
 //      Playback
 // ----------------------------------------------------------------------------
 
-AudioFlinger::PlaybackThread::PlaybackThread(const sp<AudioFlinger>& audioFlinger,
+PlaybackThread::PlaybackThread(const sp<AudioFlinger>& audioFlinger,
                                              AudioStreamOut* output,
                                              audio_io_handle_t id,
                                              type_t type,
@@ -2129,7 +2132,7 @@
     mStreamTypes[AUDIO_STREAM_CALL_ASSISTANT].mute = false;
 }
 
-AudioFlinger::PlaybackThread::~PlaybackThread()
+PlaybackThread::~PlaybackThread()
 {
     mAudioFlinger->unregisterWriter(mNBLogWriter);
     free(mSinkBuffer);
@@ -2140,7 +2143,7 @@
 
 // Thread virtuals
 
-void AudioFlinger::PlaybackThread::onFirstRef()
+void PlaybackThread::onFirstRef()
 {
     if (!isStreamInitialized()) {
         ALOGE("The stream is not open yet"); // This should not happen.
@@ -2155,7 +2158,7 @@
         if (mOutput->flags & AUDIO_OUTPUT_FLAG_NON_BLOCKING &&
                 mOutput->stream->setCallback(this) == OK) {
             mUseAsyncWrite = true;
-            mCallbackThread = new AudioFlinger::AsyncCallbackThread(this);
+            mCallbackThread = sp<AsyncCallbackThread>::make(this);
         }
 
         if (mOutput->stream->setEventCallback(this) != OK) {
@@ -2167,14 +2170,14 @@
 }
 
 // ThreadBase virtuals
-void AudioFlinger::PlaybackThread::preExit()
+void PlaybackThread::preExit()
 {
     ALOGV("  preExit()");
     status_t result = mOutput->stream->exit();
     ALOGE_IF(result != OK, "Error when calling exit(): %d", result);
 }
 
-void AudioFlinger::PlaybackThread::dumpTracks_l(int fd, const Vector<String16>& args __unused)
+void PlaybackThread::dumpTracks_l(int fd, const Vector<String16>& /* args */)
 {
     String8 result;
 
@@ -2239,7 +2242,7 @@
     write(fd, result.string(), result.size());
 }
 
-void AudioFlinger::PlaybackThread::dumpInternals_l(int fd, const Vector<String16>& args)
+void PlaybackThread::dumpInternals_l(int fd, const Vector<String16>& args)
 {
     dprintf(fd, "  Master volume: %f\n", mMasterVolume);
     dprintf(fd, "  Master mute: %s\n", mMasterMute ? "on" : "off");
@@ -2275,7 +2278,7 @@
 }
 
 // PlaybackThread::createTrack_l() must be called with AudioFlinger::mLock held
-sp<IAfTrack> AudioFlinger::PlaybackThread::createTrack_l(
+sp<IAfTrack> PlaybackThread::createTrack_l(
         const sp<Client>& client,
         audio_stream_type_t streamType,
         const audio_attributes_t& attr,
@@ -2660,7 +2663,7 @@
 }
 
 template<typename T>
-ssize_t AudioFlinger::PlaybackThread::Tracks<T>::remove(const sp<T> &track)
+ssize_t PlaybackThread::Tracks<T>::remove(const sp<T>& track)
 {
     const int trackId = track->id();
     const ssize_t index = mTracks.remove(track);
@@ -2675,17 +2678,17 @@
     return index;
 }
 
-uint32_t AudioFlinger::PlaybackThread::correctLatency_l(uint32_t latency) const
+uint32_t PlaybackThread::correctLatency_l(uint32_t latency) const
 {
     return latency;
 }
 
-uint32_t AudioFlinger::PlaybackThread::latency() const
+uint32_t PlaybackThread::latency() const
 {
     Mutex::Autolock _l(mLock);
     return latency_l();
 }
-uint32_t AudioFlinger::PlaybackThread::latency_l() const
+uint32_t PlaybackThread::latency_l() const
 {
     uint32_t latency;
     if (initCheck() == NO_ERROR && mOutput->stream->getLatency(&latency) == OK) {
@@ -2694,7 +2697,7 @@
     return 0;
 }
 
-void AudioFlinger::PlaybackThread::setMasterVolume(float value)
+void PlaybackThread::setMasterVolume(float value)
 {
     Mutex::Autolock _l(mLock);
     // Don't apply master volume in SW if our HAL can do it for us.
@@ -2706,12 +2709,12 @@
     }
 }
 
-void AudioFlinger::PlaybackThread::setMasterBalance(float balance)
+void PlaybackThread::setMasterBalance(float balance)
 {
     mMasterBalance.store(balance);
 }
 
-void AudioFlinger::PlaybackThread::setMasterMute(bool muted)
+void PlaybackThread::setMasterMute(bool muted)
 {
     if (isDuplicating()) {
         return;
@@ -2726,33 +2729,33 @@
     }
 }
 
-void AudioFlinger::PlaybackThread::setStreamVolume(audio_stream_type_t stream, float value)
+void PlaybackThread::setStreamVolume(audio_stream_type_t stream, float value)
 {
     Mutex::Autolock _l(mLock);
     mStreamTypes[stream].volume = value;
     broadcast_l();
 }
 
-void AudioFlinger::PlaybackThread::setStreamMute(audio_stream_type_t stream, bool muted)
+void PlaybackThread::setStreamMute(audio_stream_type_t stream, bool muted)
 {
     Mutex::Autolock _l(mLock);
     mStreamTypes[stream].mute = muted;
     broadcast_l();
 }
 
-float AudioFlinger::PlaybackThread::streamVolume(audio_stream_type_t stream) const
+float PlaybackThread::streamVolume(audio_stream_type_t stream) const
 {
     Mutex::Autolock _l(mLock);
     return mStreamTypes[stream].volume;
 }
 
-void AudioFlinger::PlaybackThread::setVolumeForOutput_l(float left, float right) const
+void PlaybackThread::setVolumeForOutput_l(float left, float right) const
 {
     mOutput->stream->setVolume(left, right);
 }
 
 // addTrack_l() must be called with ThreadBase::mLock held
-status_t AudioFlinger::PlaybackThread::addTrack_l(const sp<IAfTrack>& track)
+status_t PlaybackThread::addTrack_l(const sp<IAfTrack>& track)
 NO_THREAD_SAFETY_ANALYSIS  // release and re-acquire mLock
 {
     status_t status = ALREADY_EXISTS;
@@ -2858,7 +2861,7 @@
     return status;
 }
 
-bool AudioFlinger::PlaybackThread::destroyTrack_l(const sp<IAfTrack>& track)
+bool PlaybackThread::destroyTrack_l(const sp<IAfTrack>& track)
 {
     track->terminate();
     // active tracks are removed by threadLoop()
@@ -2876,7 +2879,7 @@
     return trackActive;
 }
 
-void AudioFlinger::PlaybackThread::removeTrack_l(const sp<IAfTrack>& track)
+void PlaybackThread::removeTrack_l(const sp<IAfTrack>& track)
 {
     track->triggerEvents(AudioSystem::SYNC_EVENT_PRESENTATION_COMPLETE);
 
@@ -2903,7 +2906,7 @@
     }
 }
 
-String8 AudioFlinger::PlaybackThread::getParameters(const String8& keys)
+String8 PlaybackThread::getParameters(const String8& keys)
 {
     Mutex::Autolock _l(mLock);
     String8 out_s8;
@@ -2913,7 +2916,7 @@
     return {};
 }
 
-status_t AudioFlinger::DirectOutputThread::selectPresentation(int presentationId, int programId) {
+status_t DirectOutputThread::selectPresentation(int presentationId, int programId) {
     Mutex::Autolock _l(mLock);
     if (!isStreamInitialized()) {
         return NO_INIT;
@@ -2921,7 +2924,7 @@
     return mOutput->stream->selectPresentation(presentationId, programId);
 }
 
-void AudioFlinger::PlaybackThread::ioConfigChanged(audio_io_config_event_t event, pid_t pid,
+void PlaybackThread::ioConfigChanged(audio_io_config_event_t event, pid_t pid,
                                                    audio_port_handle_t portId) {
     ALOGV("PlaybackThread::ioConfigChanged, thread %p, event %d", this, event);
     sp<AudioIoDescriptor> desc;
@@ -2946,27 +2949,27 @@
     mAudioFlinger->ioConfigChanged(event, desc, pid);
 }
 
-void AudioFlinger::PlaybackThread::onWriteReady()
+void PlaybackThread::onWriteReady()
 {
     mCallbackThread->resetWriteBlocked();
 }
 
-void AudioFlinger::PlaybackThread::onDrainReady()
+void PlaybackThread::onDrainReady()
 {
     mCallbackThread->resetDraining();
 }
 
-void AudioFlinger::PlaybackThread::onError()
+void PlaybackThread::onError()
 {
     mCallbackThread->setAsyncError();
 }
 
-void AudioFlinger::PlaybackThread::onCodecFormatChanged(
+void PlaybackThread::onCodecFormatChanged(
         const std::basic_string<uint8_t>& metadataBs)
 {
-    wp<AudioFlinger::PlaybackThread> weakPointerThis = this;
+    const auto weakPointerThis = wp<PlaybackThread>::fromExisting(this);
     std::thread([this, metadataBs, weakPointerThis]() {
-            sp<AudioFlinger::PlaybackThread> playbackThread = weakPointerThis.promote();
+            const sp<PlaybackThread> playbackThread = weakPointerThis.promote();
             if (playbackThread == nullptr) {
                 ALOGW("PlaybackThread was destroyed, skip codec format change event");
                 return;
@@ -2991,7 +2994,7 @@
     }).detach();
 }
 
-void AudioFlinger::PlaybackThread::resetWriteBlocked(uint32_t sequence)
+void PlaybackThread::resetWriteBlocked(uint32_t sequence)
 {
     Mutex::Autolock _l(mLock);
     // reject out of sequence requests
@@ -3001,7 +3004,7 @@
     }
 }
 
-void AudioFlinger::PlaybackThread::resetDraining(uint32_t sequence)
+void PlaybackThread::resetDraining(uint32_t sequence)
 {
     Mutex::Autolock _l(mLock);
     // reject out of sequence requests
@@ -3016,7 +3019,7 @@
     }
 }
 
-void AudioFlinger::PlaybackThread::readOutputParameters_l()
+void PlaybackThread::readOutputParameters_l()
 {
     // unfortunately we have no way of recovering from errors here, hence the LOG_ALWAYS_FATAL
     const audio_config_base_t audioConfig = mOutput->getAudioProperties();
@@ -3025,7 +3028,7 @@
     if (!audio_is_output_channel(mChannelMask)) {
         LOG_ALWAYS_FATAL("HAL channel mask %#x not valid for output", mChannelMask);
     }
-    if (hasMixer() && !isValidPcmSinkChannelMask(mChannelMask)) {
+    if (hasMixer() && !AudioFlinger::isValidPcmSinkChannelMask(mChannelMask)) {
         LOG_ALWAYS_FATAL("HAL channel mask %#x not supported for mixed output",
                 mChannelMask);
     }
@@ -3048,7 +3051,7 @@
     if (!audio_is_valid_format(mFormat)) {
         LOG_ALWAYS_FATAL("HAL format %#x not valid for output", mFormat);
     }
-    if (hasMixer() && !isValidPcmSinkFormat(mFormat)) {
+    if (hasMixer() && !AudioFlinger::isValidPcmSinkFormat(mFormat)) {
         LOG_FATAL("HAL format %#x not supported for mixed output",
                 mFormat);
     }
@@ -3216,7 +3219,7 @@
     item.record();
 }
 
-AudioFlinger::ThreadBase::MetadataUpdate AudioFlinger::PlaybackThread::updateMetadata_l()
+ThreadBase::MetadataUpdate PlaybackThread::updateMetadata_l()
 {
     if (!isStreamInitialized() || !mActiveTracks.readAndClearHasChanged()) {
         return {}; // nothing to do
@@ -3233,13 +3236,13 @@
     return change;
 }
 
-void AudioFlinger::PlaybackThread::sendMetadataToBackend_l(
+void PlaybackThread::sendMetadataToBackend_l(
         const StreamOutHalInterface::SourceMetadata& metadata)
 {
     mOutput->stream->updateSourceMetadata(metadata);
 };
 
-status_t AudioFlinger::PlaybackThread::getRenderPosition(
+status_t PlaybackThread::getRenderPosition(
         uint32_t* halFrames, uint32_t* dspFrames) const
 {
     if (halFrames == NULL || dspFrames == NULL) {
@@ -3267,8 +3270,7 @@
     }
 }
 
-product_strategy_t AudioFlinger::PlaybackThread::getStrategyForSession_l(
-        audio_session_t sessionId) const
+product_strategy_t PlaybackThread::getStrategyForSession_l(audio_session_t sessionId) const
 {
     // session AUDIO_SESSION_OUTPUT_MIX is placed in same strategy as MUSIC stream so that
     // it is moved to correct output by audio policy manager when A2DP is connected or disconnected
@@ -3285,13 +3287,13 @@
 }
 
 
-AudioStreamOut* AudioFlinger::PlaybackThread::getOutput() const
+AudioStreamOut* PlaybackThread::getOutput() const
 {
     Mutex::Autolock _l(mLock);
     return mOutput;
 }
 
-AudioStreamOut* AudioFlinger::PlaybackThread::clearOutput()
+AudioStreamOut* PlaybackThread::clearOutput()
 {
     Mutex::Autolock _l(mLock);
     AudioStreamOut *output = mOutput;
@@ -3305,7 +3307,7 @@
 }
 
 // this method must always be called either with ThreadBase mLock held or inside the thread loop
-sp<StreamHalInterface> AudioFlinger::PlaybackThread::stream() const
+sp<StreamHalInterface> PlaybackThread::stream() const
 {
     if (mOutput == NULL) {
         return NULL;
@@ -3313,12 +3315,12 @@
     return mOutput->stream;
 }
 
-uint32_t AudioFlinger::PlaybackThread::activeSleepTimeUs() const
+uint32_t PlaybackThread::activeSleepTimeUs() const
 {
     return (uint32_t)((uint32_t)((mNormalFrameCount * 1000) / mSampleRate) * 1000);
 }
 
-status_t AudioFlinger::PlaybackThread::setSyncEvent(const sp<audioflinger::SyncEvent>& event)
+status_t PlaybackThread::setSyncEvent(const sp<SyncEvent>& event)
 {
     if (!isValidSyncEvent(event)) {
         return BAD_VALUE;
@@ -3337,13 +3339,12 @@
     return NAME_NOT_FOUND;
 }
 
-bool AudioFlinger::PlaybackThread::isValidSyncEvent(
-        const sp<audioflinger::SyncEvent>& event) const
+bool PlaybackThread::isValidSyncEvent(const sp<SyncEvent>& event) const
 {
     return event->type() == AudioSystem::SYNC_EVENT_PRESENTATION_COMPLETE;
 }
 
-void AudioFlinger::PlaybackThread::threadLoop_removeTracks(
+void PlaybackThread::threadLoop_removeTracks(
         [[maybe_unused]] const Vector<sp<IAfTrack>>& tracksToRemove)
 {
     // Miscellaneous track cleanup when removed from the active list,
@@ -3358,7 +3359,7 @@
 #endif
 }
 
-void AudioFlinger::PlaybackThread::checkSilentMode_l()
+void PlaybackThread::checkSilentMode_l()
 {
     if (!mMasterMute) {
         char value[PROPERTY_VALUE_MAX];
@@ -3384,7 +3385,7 @@
 }
 
 // shared by MIXER and DIRECT, overridden by DUPLICATING
-ssize_t AudioFlinger::PlaybackThread::threadLoop_write()
+ssize_t PlaybackThread::threadLoop_write()
 {
     LOG_HIST_TS();
     mInWrite = true;
@@ -3456,7 +3457,7 @@
 }
 
 // startMelComputation_l() must be called with AudioFlinger::mLock held
-void AudioFlinger::PlaybackThread::startMelComputation_l(
+void PlaybackThread::startMelComputation_l(
         const sp<audio_utils::MelProcessor>& processor)
 {
     auto outputSink = static_cast<AudioStreamOutSink*>(mOutputSink.get());
@@ -3466,7 +3467,7 @@
 }
 
 // stopMelComputation_l() must be called with AudioFlinger::mLock held
-void AudioFlinger::PlaybackThread::stopMelComputation_l()
+void PlaybackThread::stopMelComputation_l()
 {
     auto outputSink = static_cast<AudioStreamOutSink*>(mOutputSink.get());
     if (outputSink != nullptr) {
@@ -3474,7 +3475,7 @@
     }
 }
 
-void AudioFlinger::PlaybackThread::threadLoop_drain()
+void PlaybackThread::threadLoop_drain()
 {
     bool supportsDrain = false;
     if (mOutput->stream->supportsDrain(&supportsDrain) == OK && supportsDrain) {
@@ -3490,7 +3491,7 @@
     }
 }
 
-void AudioFlinger::PlaybackThread::threadLoop_exit()
+void PlaybackThread::threadLoop_exit()
 {
     {
         Mutex::Autolock _l(mLock);
@@ -3526,7 +3527,7 @@
  - idle sleep time
 */
 
-void AudioFlinger::PlaybackThread::cacheParameters_l()
+void PlaybackThread::cacheParameters_l()
 {
     mSinkBufferSize = mNormalFrameCount * mFrameSize;
     mActiveSleepTimeUs = activeSleepTimeUs();
@@ -3543,7 +3544,7 @@
     }
 }
 
-bool AudioFlinger::PlaybackThread::invalidateTracks_l(audio_stream_type_t streamType)
+bool PlaybackThread::invalidateTracks_l(audio_stream_type_t streamType)
 {
     ALOGV("MixerThread::invalidateTracks() mixer %p, streamType %d, mTracks.size %zu",
             this,  streamType, mTracks.size());
@@ -3559,18 +3560,18 @@
     return trackMatch;
 }
 
-void AudioFlinger::PlaybackThread::invalidateTracks(audio_stream_type_t streamType)
+void PlaybackThread::invalidateTracks(audio_stream_type_t streamType)
 {
     Mutex::Autolock _l(mLock);
     invalidateTracks_l(streamType);
 }
 
-void AudioFlinger::PlaybackThread::invalidateTracks(std::set<audio_port_handle_t>& portIds) {
+void PlaybackThread::invalidateTracks(std::set<audio_port_handle_t>& portIds) {
     Mutex::Autolock _l(mLock);
     invalidateTracks_l(portIds);
 }
 
-bool AudioFlinger::PlaybackThread::invalidateTracks_l(std::set<audio_port_handle_t>& portIds) {
+bool PlaybackThread::invalidateTracks_l(std::set<audio_port_handle_t>& portIds) {
     bool trackMatch = false;
     const size_t size = mTracks.size();
     for (size_t i = 0; i < size; i++) {
@@ -3588,7 +3589,7 @@
 }
 
 // getTrackById_l must be called with holding thread lock
-IAfTrack* AudioFlinger::PlaybackThread::getTrackById_l(
+IAfTrack* PlaybackThread::getTrackById_l(
         audio_port_handle_t trackPortId) {
     for (size_t i = 0; i < mTracks.size(); i++) {
         if (mTracks[i]->portId() == trackPortId) {
@@ -3598,7 +3599,7 @@
     return nullptr;
 }
 
-status_t AudioFlinger::PlaybackThread::addEffectChain_l(const sp<IAfEffectChain>& chain)
+status_t PlaybackThread::addEffectChain_l(const sp<IAfEffectChain>& chain)
 {
     audio_session_t session = chain->sessionId();
     sp<EffectBufferHalInterface> halInBuffer, halOutBuffer;
@@ -3734,7 +3735,7 @@
     return NO_ERROR;
 }
 
-size_t AudioFlinger::PlaybackThread::removeEffectChain_l(const sp<IAfEffectChain>& chain)
+size_t PlaybackThread::removeEffectChain_l(const sp<IAfEffectChain>& chain)
 {
     audio_session_t session = chain->sessionId();
 
@@ -3766,14 +3767,14 @@
     return mEffectChains.size();
 }
 
-status_t AudioFlinger::PlaybackThread::attachAuxEffect(
+status_t PlaybackThread::attachAuxEffect(
         const sp<IAfTrack>& track, int EffectId)
 {
     Mutex::Autolock _l(mLock);
     return attachAuxEffect_l(track, EffectId);
 }
 
-status_t AudioFlinger::PlaybackThread::attachAuxEffect_l(
+status_t PlaybackThread::attachAuxEffect_l(
         const sp<IAfTrack>& track, int EffectId)
 {
     status_t status = NO_ERROR;
@@ -3796,7 +3797,7 @@
     return status;
 }
 
-void AudioFlinger::PlaybackThread::detachAuxEffect_l(int effectId)
+void PlaybackThread::detachAuxEffect_l(int effectId)
 {
     for (size_t i = 0; i < mTracks.size(); ++i) {
         sp<IAfTrack> track = mTracks[i];
@@ -3806,7 +3807,7 @@
     }
 }
 
-bool AudioFlinger::PlaybackThread::threadLoop()
+bool PlaybackThread::threadLoop()
 NO_THREAD_SAFETY_ANALYSIS  // manual locking of AudioFlinger
 {
     aflog::setThreadWriter(mNBLogWriter.get());
@@ -3875,7 +3876,7 @@
             // Here, we try for the AF lock, but do not block on it as the latency
             // is more informational.
             if (mAudioFlinger->mLock.tryLock() == NO_ERROR) {
-                std::vector<PatchPanel::SoftwarePatch> swPatches;
+                std::vector<AudioFlinger::PatchPanel::SoftwarePatch> swPatches;
                 double latencyMs = 0.; // not required; initialized for clang-tidy
                 status_t status = INVALID_OPERATION;
                 audio_patch_handle_t downstreamPatchHandle = AUDIO_PATCH_HANDLE_NONE;
@@ -4462,7 +4463,7 @@
     return false;
 }
 
-void AudioFlinger::PlaybackThread::collectTimestamps_l()
+void PlaybackThread::collectTimestamps_l()
 {
     if (mStandby) {
         mTimestampVerifier.discontinuity(discontinuityForStandbyOrFlush());
@@ -4598,7 +4599,7 @@
 }
 
 // removeTracks_l() must be called with ThreadBase::mLock held
-void AudioFlinger::PlaybackThread::removeTracks_l(const Vector<sp<IAfTrack>>& tracksToRemove)
+void PlaybackThread::removeTracks_l(const Vector<sp<IAfTrack>>& tracksToRemove)
 NO_THREAD_SAFETY_ANALYSIS  // release and re-acquire mLock
 {
     for (const auto& track : tracksToRemove) {
@@ -4640,7 +4641,7 @@
     }
 }
 
-status_t AudioFlinger::PlaybackThread::getTimestamp_l(AudioTimestamp& timestamp)
+status_t PlaybackThread::getTimestamp_l(AudioTimestamp& timestamp)
 {
     if (mNormalSink != 0) {
         ExtendedTimestamp ets;
@@ -4669,7 +4670,7 @@
 // All tracks attached to a mixer with flag VOIP_RX are tied to the same
 // stream type STREAM_VOICE_CALL so this will only change the HAL volume once even
 // if more than one track are active
-status_t AudioFlinger::PlaybackThread::handleVoipVolume_l(float *volume)
+status_t PlaybackThread::handleVoipVolume_l(float* volume)
 {
     status_t result = NO_ERROR;
     if ((mOutput->flags & AUDIO_OUTPUT_FLAG_VOIP_RX) != 0) {
@@ -4691,7 +4692,7 @@
     return result;
 }
 
-status_t AudioFlinger::MixerThread::createAudioPatch_l(const struct audio_patch *patch,
+status_t MixerThread::createAudioPatch_l(const struct audio_patch* patch,
                                                           audio_patch_handle_t *handle)
 {
     status_t status;
@@ -4708,7 +4709,7 @@
     return status;
 }
 
-status_t AudioFlinger::PlaybackThread::createAudioPatch_l(const struct audio_patch *patch,
+status_t PlaybackThread::createAudioPatch_l(const struct audio_patch *patch,
                                                           audio_patch_handle_t *handle)
 {
     status_t status = NO_ERROR;
@@ -4792,7 +4793,7 @@
     return status;
 }
 
-status_t AudioFlinger::MixerThread::releaseAudioPatch_l(const audio_patch_handle_t handle)
+status_t MixerThread::releaseAudioPatch_l(const audio_patch_handle_t handle)
 {
     status_t status;
     if (property_get_bool("af.patch_park", false /* default_value */)) {
@@ -4806,7 +4807,7 @@
     return status;
 }
 
-status_t AudioFlinger::PlaybackThread::releaseAudioPatch_l(const audio_patch_handle_t handle)
+status_t PlaybackThread::releaseAudioPatch_l(const audio_patch_handle_t handle)
 {
     status_t status = NO_ERROR;
 
@@ -4825,19 +4826,19 @@
     return status;
 }
 
-void AudioFlinger::PlaybackThread::addPatchTrack(const sp<IAfPatchTrack>& track)
+void PlaybackThread::addPatchTrack(const sp<IAfPatchTrack>& track)
 {
     Mutex::Autolock _l(mLock);
     mTracks.add(track);
 }
 
-void AudioFlinger::PlaybackThread::deletePatchTrack(const sp<IAfPatchTrack>& track)
+void PlaybackThread::deletePatchTrack(const sp<IAfPatchTrack>& track)
 {
     Mutex::Autolock _l(mLock);
     destroyTrack_l(track);
 }
 
-void AudioFlinger::PlaybackThread::toAudioPortConfig(struct audio_port_config *config)
+void PlaybackThread::toAudioPortConfig(struct audio_port_config* config)
 {
     ThreadBase::toAudioPortConfig(config);
     config->role = AUDIO_PORT_ROLE_SOURCE;
@@ -4851,7 +4852,14 @@
 
 // ----------------------------------------------------------------------------
 
-AudioFlinger::MixerThread::MixerThread(const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output,
+/* static */
+sp<IAfPlaybackThread> IAfPlaybackThread::createMixerThread(
+        const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output,
+        audio_io_handle_t id, bool systemReady, type_t type, audio_config_base_t* mixerConfig) {
+    return sp<MixerThread>::make(audioFlinger, output, id, systemReady, type, mixerConfig);
+}
+
+MixerThread::MixerThread(const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output,
         audio_io_handle_t id, bool systemReady, type_t type, audio_config_base_t *mixerConfig)
     :   PlaybackThread(audioFlinger, output, id, type, systemReady, mixerConfig),
         // mAudioMixer below
@@ -5036,7 +5044,7 @@
     }
 }
 
-AudioFlinger::MixerThread::~MixerThread()
+MixerThread::~MixerThread()
 {
     if (mFastMixer != 0) {
         FastMixerStateQueue *sq = mFastMixer->sq();
@@ -5073,7 +5081,7 @@
     delete mAudioMixer;
 }
 
-void AudioFlinger::MixerThread::onFirstRef() {
+void MixerThread::onFirstRef() {
     PlaybackThread::onFirstRef();
 
     Mutex::Autolock _l(mLock);
@@ -5089,7 +5097,7 @@
     }
 }
 
-uint32_t AudioFlinger::MixerThread::correctLatency_l(uint32_t latency) const
+uint32_t MixerThread::correctLatency_l(uint32_t latency) const
 {
     if (mFastMixer != 0) {
         MonoPipe *pipe = (MonoPipe *)mPipeSink.get();
@@ -5098,7 +5106,7 @@
     return latency;
 }
 
-ssize_t AudioFlinger::MixerThread::threadLoop_write()
+ssize_t MixerThread::threadLoop_write()
 {
     // FIXME we should only do one push per cycle; confirm this is true
     // Start the fast mixer if it's not already running
@@ -5141,7 +5149,7 @@
     return PlaybackThread::threadLoop_write();
 }
 
-void AudioFlinger::MixerThread::threadLoop_standby()
+void MixerThread::threadLoop_standby()
 {
     // Idle the fast mixer if it's currently running
     if (mFastMixer != 0) {
@@ -5179,24 +5187,24 @@
     PlaybackThread::threadLoop_standby();
 }
 
-bool AudioFlinger::PlaybackThread::waitingAsyncCallback_l()
+bool PlaybackThread::waitingAsyncCallback_l()
 {
     return false;
 }
 
-bool AudioFlinger::PlaybackThread::shouldStandby_l()
+bool PlaybackThread::shouldStandby_l()
 {
     return !mStandby;
 }
 
-bool AudioFlinger::PlaybackThread::waitingAsyncCallback()
+bool PlaybackThread::waitingAsyncCallback()
 {
     Mutex::Autolock _l(mLock);
     return waitingAsyncCallback_l();
 }
 
 // shared by MIXER and DIRECT, overridden by DUPLICATING
-void AudioFlinger::PlaybackThread::threadLoop_standby()
+void PlaybackThread::threadLoop_standby()
 {
     ALOGV("Audio hardware entering standby, mixer %p, suspend count %d", this, mSuspended);
     mOutput->standby();
@@ -5212,20 +5220,20 @@
     setHalLatencyMode_l();
 }
 
-void AudioFlinger::PlaybackThread::onAddNewTrack_l()
+void PlaybackThread::onAddNewTrack_l()
 {
     ALOGV("signal playback thread");
     broadcast_l();
 }
 
-void AudioFlinger::PlaybackThread::onAsyncError()
+void PlaybackThread::onAsyncError()
 {
     for (int i = AUDIO_STREAM_SYSTEM; i < (int)AUDIO_STREAM_CNT; i++) {
         invalidateTracks((audio_stream_type_t)i);
     }
 }
 
-void AudioFlinger::MixerThread::threadLoop_mix()
+void MixerThread::threadLoop_mix()
 {
     // mix buffers...
     mAudioMixer->process();
@@ -5243,7 +5251,7 @@
 
 }
 
-void AudioFlinger::MixerThread::threadLoop_sleepTime()
+void MixerThread::threadLoop_sleepTime()
 {
     // If no tracks are ready, sleep once for the duration of an output
     // buffer size, then write 0s to the output
@@ -5297,7 +5305,7 @@
 }
 
 // prepareTracks_l() must be called with ThreadBase::mLock held
-AudioFlinger::PlaybackThread::mixer_state AudioFlinger::MixerThread::prepareTracks_l(
+PlaybackThread::mixer_state MixerThread::prepareTracks_l(
         Vector<sp<IAfTrack>>* tracksToRemove)
 {
     // clean up deleted track ids in AudioMixer before allocating new tracks
@@ -6093,7 +6101,7 @@
 }
 
 // trackCountForUid_l() must be called with ThreadBase::mLock held
-uint32_t AudioFlinger::PlaybackThread::trackCountForUid_l(uid_t uid) const
+uint32_t PlaybackThread::trackCountForUid_l(uid_t uid) const
 {
     uint32_t trackCount = 0;
     for (size_t i = 0; i < mTracks.size() ; i++) {
@@ -6104,7 +6112,7 @@
     return trackCount;
 }
 
-bool AudioFlinger::PlaybackThread::IsTimestampAdvancing::check(AudioStreamOut * output)
+bool PlaybackThread::IsTimestampAdvancing::check(AudioStreamOut* output)
 {
     // Check the timestamp to see if it's advancing once every 150ms. If we check too frequently, we
     // could falsely detect that the frame position has stalled due to underrun because we haven't
@@ -6128,7 +6136,7 @@
     return mLatchedValue;
 }
 
-void AudioFlinger::PlaybackThread::IsTimestampAdvancing::clear()
+void PlaybackThread::IsTimestampAdvancing::clear()
 {
     mLatchedValue = true;
     mPreviousPosition = 0;
@@ -6136,7 +6144,7 @@
 }
 
 // isTrackAllowed_l() must be called with ThreadBase::mLock held
-bool AudioFlinger::MixerThread::isTrackAllowed_l(
+bool MixerThread::isTrackAllowed_l(
         audio_channel_mask_t channelMask, audio_format_t format,
         audio_session_t sessionId, uid_t uid) const
 {
@@ -6156,7 +6164,7 @@
 }
 
 // checkForNewParameter_l() must be called with ThreadBase::mLock held
-bool AudioFlinger::MixerThread::checkForNewParameter_l(const String8& keyValuePair,
+bool MixerThread::checkForNewParameter_l(const String8& keyValuePair,
                                                        status_t& status)
 {
     bool reconfig = false;
@@ -6170,7 +6178,7 @@
         reconfig = true;
     }
     if (param.getInt(String8(AudioParameter::keyFormat), value) == NO_ERROR) {
-        if (!isValidPcmSinkFormat((audio_format_t) value)) {
+        if (!AudioFlinger::isValidPcmSinkFormat(static_cast<audio_format_t>(value))) {
             status = BAD_VALUE;
         } else {
             // no need to save value, since it's constant
@@ -6178,7 +6186,7 @@
         }
     }
     if (param.getInt(String8(AudioParameter::keyChannels), value) == NO_ERROR) {
-        if (!isValidPcmSinkChannelMask((audio_channel_mask_t) value)) {
+        if (!AudioFlinger::isValidPcmSinkChannelMask(static_cast<audio_channel_mask_t>(value))) {
             status = BAD_VALUE;
         } else {
             // no need to save value, since it's constant
@@ -6236,7 +6244,7 @@
 }
 
 
-void AudioFlinger::MixerThread::dumpInternals_l(int fd, const Vector<String16>& args)
+void MixerThread::dumpInternals_l(int fd, const Vector<String16>& args)
 {
     PlaybackThread::dumpInternals_l(fd, args);
     dprintf(fd, "  Thread throttle time (msecs): %u\n", mThreadThrottleTimeMs);
@@ -6283,17 +6291,17 @@
      dprintf(fd, "Supported latency modes: %s\n", toString(mSupportedLatencyModes).c_str());
 }
 
-uint32_t AudioFlinger::MixerThread::idleSleepTimeUs() const
+uint32_t MixerThread::idleSleepTimeUs() const
 {
     return (uint32_t)(((mNormalFrameCount * 1000) / mSampleRate) * 1000) / 2;
 }
 
-uint32_t AudioFlinger::MixerThread::suspendSleepTimeUs() const
+uint32_t MixerThread::suspendSleepTimeUs() const
 {
     return (uint32_t)(((mNormalFrameCount * 1000) / mSampleRate) * 1000);
 }
 
-void AudioFlinger::MixerThread::cacheParameters_l()
+void MixerThread::cacheParameters_l()
 {
     PlaybackThread::cacheParameters_l();
 
@@ -6304,11 +6312,11 @@
     maxPeriod = seconds(mNormalFrameCount) / mSampleRate * 15;
 }
 
-void AudioFlinger::MixerThread::onHalLatencyModesChanged_l() {
+void MixerThread::onHalLatencyModesChanged_l() {
     mAudioFlinger->onSupportedLatencyModesChanged(mId, mSupportedLatencyModes);
 }
 
-void AudioFlinger::MixerThread::setHalLatencyMode_l() {
+void MixerThread::setHalLatencyMode_l() {
     // Only handle latency mode if:
     // - mBluetoothLatencyModesEnabled is true
     // - the HAL supports latency modes
@@ -6350,7 +6358,7 @@
     }
 }
 
-void AudioFlinger::MixerThread::updateHalSupportedLatencyModes_l() {
+void MixerThread::updateHalSupportedLatencyModes_l() {
 
     if (mOutput == nullptr || mOutput->stream == nullptr) {
         return;
@@ -6368,7 +6376,7 @@
     }
 }
 
-status_t AudioFlinger::MixerThread::getSupportedLatencyModes(
+status_t MixerThread::getSupportedLatencyModes(
         std::vector<audio_latency_mode_t>* modes) {
     if (modes == nullptr) {
         return BAD_VALUE;
@@ -6378,7 +6386,7 @@
     return NO_ERROR;
 }
 
-void AudioFlinger::MixerThread::onRecommendedLatencyModeChanged(
+void MixerThread::onRecommendedLatencyModeChanged(
         std::vector<audio_latency_mode_t> modes) {
     Mutex::Autolock _l(mLock);
     if (modes != mSupportedLatencyModes) {
@@ -6389,7 +6397,7 @@
     }
 }
 
-status_t AudioFlinger::MixerThread::setBluetoothVariableLatencyEnabled(bool enabled) {
+status_t MixerThread::setBluetoothVariableLatencyEnabled(bool enabled) {
     if (mOutput == nullptr || mOutput->audioHwDev == nullptr
             || !mOutput->audioHwDev->supportsBluetoothVariableLatency()) {
         return INVALID_OPERATION;
@@ -6400,7 +6408,16 @@
 
 // ----------------------------------------------------------------------------
 
-AudioFlinger::DirectOutputThread::DirectOutputThread(const sp<AudioFlinger>& audioFlinger,
+/* static */
+sp<IAfPlaybackThread> IAfPlaybackThread::createDirectOutputThread(
+        const sp<AudioFlinger>& audioFlinger,
+        AudioStreamOut* output, audio_io_handle_t id, bool systemReady,
+        const audio_offload_info_t& offloadInfo) {
+    return sp<DirectOutputThread>::make(
+            audioFlinger, output, id, systemReady, offloadInfo);
+}
+
+DirectOutputThread::DirectOutputThread(const sp<AudioFlinger>& audioFlinger,
         AudioStreamOut* output, audio_io_handle_t id, ThreadBase::type_t type, bool systemReady,
         const audio_offload_info_t& offloadInfo)
     :   PlaybackThread(audioFlinger, output, id, type, systemReady)
@@ -6409,18 +6426,18 @@
     setMasterBalance(audioFlinger->getMasterBalance_l());
 }
 
-AudioFlinger::DirectOutputThread::~DirectOutputThread()
+DirectOutputThread::~DirectOutputThread()
 {
 }
 
-void AudioFlinger::DirectOutputThread::dumpInternals_l(int fd, const Vector<String16>& args)
+void DirectOutputThread::dumpInternals_l(int fd, const Vector<String16>& args)
 {
     PlaybackThread::dumpInternals_l(fd, args);
     dprintf(fd, "  Master balance: %f  Left: %f  Right: %f\n",
             mMasterBalance.load(), mMasterBalanceLeft, mMasterBalanceRight);
 }
 
-void AudioFlinger::DirectOutputThread::setMasterBalance(float balance)
+void DirectOutputThread::setMasterBalance(float balance)
 {
     Mutex::Autolock _l(mLock);
     if (mMasterBalance != balance) {
@@ -6430,7 +6447,7 @@
     }
 }
 
-void AudioFlinger::DirectOutputThread::processVolume_l(IAfTrack *track, bool lastTrack)
+void DirectOutputThread::processVolume_l(IAfTrack* track, bool lastTrack)
 {
     float left, right;
 
@@ -6509,7 +6526,7 @@
     }
 }
 
-void AudioFlinger::DirectOutputThread::onAddNewTrack_l()
+void DirectOutputThread::onAddNewTrack_l()
 {
     sp<IAfTrack> previousTrack = mPreviousTrack.promote();
     sp<IAfTrack> latestTrack = mActiveTracks.getLatest();
@@ -6534,7 +6551,7 @@
     PlaybackThread::onAddNewTrack_l();
 }
 
-AudioFlinger::PlaybackThread::mixer_state AudioFlinger::DirectOutputThread::prepareTracks_l(
+PlaybackThread::mixer_state DirectOutputThread::prepareTracks_l(
     Vector<sp<IAfTrack>>* tracksToRemove
 )
 {
@@ -6757,7 +6774,7 @@
     return mixerStatus;
 }
 
-void AudioFlinger::DirectOutputThread::threadLoop_mix()
+void DirectOutputThread::threadLoop_mix()
 {
     size_t frameCount = mFrameCount;
     int8_t *curBuf = (int8_t *)mSinkBuffer;
@@ -6784,7 +6801,7 @@
     mActiveTrack.clear();
 }
 
-void AudioFlinger::DirectOutputThread::threadLoop_sleepTime()
+void DirectOutputThread::threadLoop_sleepTime()
 {
     // do not write to HAL when paused
     if (mHwPaused || (usesHwAvSync() && mStandby)) {
@@ -6800,7 +6817,7 @@
     // linear or proportional PCM direct tracks in underrun.
 }
 
-void AudioFlinger::DirectOutputThread::threadLoop_exit()
+void DirectOutputThread::threadLoop_exit()
 {
     {
         Mutex::Autolock _l(mLock);
@@ -6818,7 +6835,7 @@
 }
 
 // must be called with thread mutex locked
-bool AudioFlinger::DirectOutputThread::shouldStandby_l()
+bool DirectOutputThread::shouldStandby_l()
 {
     bool trackPaused = false;
     bool trackStopped = false;
@@ -6835,7 +6852,7 @@
 }
 
 // checkForNewParameter_l() must be called with ThreadBase::mLock held
-bool AudioFlinger::DirectOutputThread::checkForNewParameter_l(const String8& keyValuePair,
+bool DirectOutputThread::checkForNewParameter_l(const String8& keyValuePair,
                                                               status_t& status)
 {
     bool reconfig = false;
@@ -6877,7 +6894,7 @@
     return reconfig;
 }
 
-uint32_t AudioFlinger::DirectOutputThread::activeSleepTimeUs() const
+uint32_t DirectOutputThread::activeSleepTimeUs() const
 {
     uint32_t time;
     if (audio_has_proportional_frames(mFormat)) {
@@ -6888,7 +6905,7 @@
     return time;
 }
 
-uint32_t AudioFlinger::DirectOutputThread::idleSleepTimeUs() const
+uint32_t DirectOutputThread::idleSleepTimeUs() const
 {
     uint32_t time;
     if (audio_has_proportional_frames(mFormat)) {
@@ -6899,7 +6916,7 @@
     return time;
 }
 
-uint32_t AudioFlinger::DirectOutputThread::suspendSleepTimeUs() const
+uint32_t DirectOutputThread::suspendSleepTimeUs() const
 {
     uint32_t time;
     if (audio_has_proportional_frames(mFormat)) {
@@ -6910,7 +6927,7 @@
     return time;
 }
 
-void AudioFlinger::DirectOutputThread::cacheParameters_l()
+void DirectOutputThread::cacheParameters_l()
 {
     PlaybackThread::cacheParameters_l();
 
@@ -6926,7 +6943,7 @@
     }
 }
 
-void AudioFlinger::DirectOutputThread::flushHw_l()
+void DirectOutputThread::flushHw_l()
 {
     PlaybackThread::flushHw_l();
     mOutput->flush();
@@ -6937,7 +6954,7 @@
     mMonotonicFrameCounter.onFlush();
 }
 
-int64_t AudioFlinger::DirectOutputThread::computeWaitTimeNs_l() const {
+int64_t DirectOutputThread::computeWaitTimeNs_l() const {
     // If a VolumeShaper is active, we must wake up periodically to update volume.
     const int64_t NS_PER_MS = 1000000;
     return mVolumeShaperActive ?
@@ -6946,8 +6963,8 @@
 
 // ----------------------------------------------------------------------------
 
-AudioFlinger::AsyncCallbackThread::AsyncCallbackThread(
-        const wp<AudioFlinger::PlaybackThread>& playbackThread)
+AsyncCallbackThread::AsyncCallbackThread(
+        const wp<PlaybackThread>& playbackThread)
     :   Thread(false /*canCallJava*/),
         mPlaybackThread(playbackThread),
         mWriteAckSequence(0),
@@ -6956,16 +6973,12 @@
 {
 }
 
-AudioFlinger::AsyncCallbackThread::~AsyncCallbackThread()
-{
-}
-
-void AudioFlinger::AsyncCallbackThread::onFirstRef()
+void AsyncCallbackThread::onFirstRef()
 {
     run("Offload Cbk", ANDROID_PRIORITY_URGENT_AUDIO);
 }
 
-bool AudioFlinger::AsyncCallbackThread::threadLoop()
+bool AsyncCallbackThread::threadLoop()
 {
     while (!exitPending()) {
         uint32_t writeAckSequence;
@@ -6994,7 +7007,7 @@
             mAsyncError = false;
         }
         {
-            sp<AudioFlinger::PlaybackThread> playbackThread = mPlaybackThread.promote();
+            const sp<PlaybackThread> playbackThread = mPlaybackThread.promote();
             if (playbackThread != 0) {
                 if (writeAckSequence & 1) {
                     playbackThread->resetWriteBlocked(writeAckSequence >> 1);
@@ -7011,7 +7024,7 @@
     return false;
 }
 
-void AudioFlinger::AsyncCallbackThread::exit()
+void AsyncCallbackThread::exit()
 {
     ALOGV("AsyncCallbackThread::exit");
     Mutex::Autolock _l(mLock);
@@ -7019,14 +7032,14 @@
     mWaitWorkCV.broadcast();
 }
 
-void AudioFlinger::AsyncCallbackThread::setWriteBlocked(uint32_t sequence)
+void AsyncCallbackThread::setWriteBlocked(uint32_t sequence)
 {
     Mutex::Autolock _l(mLock);
     // bit 0 is cleared
     mWriteAckSequence = sequence << 1;
 }
 
-void AudioFlinger::AsyncCallbackThread::resetWriteBlocked()
+void AsyncCallbackThread::resetWriteBlocked()
 {
     Mutex::Autolock _l(mLock);
     // ignore unexpected callbacks
@@ -7036,14 +7049,14 @@
     }
 }
 
-void AudioFlinger::AsyncCallbackThread::setDraining(uint32_t sequence)
+void AsyncCallbackThread::setDraining(uint32_t sequence)
 {
     Mutex::Autolock _l(mLock);
     // bit 0 is cleared
     mDrainSequence = sequence << 1;
 }
 
-void AudioFlinger::AsyncCallbackThread::resetDraining()
+void AsyncCallbackThread::resetDraining()
 {
     Mutex::Autolock _l(mLock);
     // ignore unexpected callbacks
@@ -7053,7 +7066,7 @@
     }
 }
 
-void AudioFlinger::AsyncCallbackThread::setAsyncError()
+void AsyncCallbackThread::setAsyncError()
 {
     Mutex::Autolock _l(mLock);
     mAsyncError = true;
@@ -7062,7 +7075,16 @@
 
 
 // ----------------------------------------------------------------------------
-AudioFlinger::OffloadThread::OffloadThread(const sp<AudioFlinger>& audioFlinger,
+
+/* static */
+sp<IAfPlaybackThread> IAfPlaybackThread::createOffloadThread(
+        const sp<AudioFlinger>& audioFlinger,
+        AudioStreamOut* output, audio_io_handle_t id, bool systemReady,
+        const audio_offload_info_t& offloadInfo) {
+    return sp<OffloadThread>::make(audioFlinger, output, id, systemReady, offloadInfo);
+}
+
+OffloadThread::OffloadThread(const sp<AudioFlinger>& audioFlinger,
         AudioStreamOut* output, audio_io_handle_t id, bool systemReady,
         const audio_offload_info_t& offloadInfo)
     :   DirectOutputThread(audioFlinger, output, id, OFFLOAD, systemReady, offloadInfo),
@@ -7073,7 +7095,7 @@
     mKeepWakeLock = property_get_bool("ro.audio.offload_wakelock", true /* default_value */);
 }
 
-void AudioFlinger::OffloadThread::threadLoop_exit()
+void OffloadThread::threadLoop_exit()
 {
     if (mFlushPending || mHwPaused) {
         // If a flush is pending or track was paused, just discard buffered data
@@ -7089,7 +7111,7 @@
     PlaybackThread::threadLoop_exit();
 }
 
-AudioFlinger::PlaybackThread::mixer_state AudioFlinger::OffloadThread::prepareTracks_l(
+PlaybackThread::mixer_state OffloadThread::prepareTracks_l(
     Vector<sp<IAfTrack>>* tracksToRemove
 )
 {
@@ -7332,7 +7354,7 @@
 }
 
 // must be called with thread mutex locked
-bool AudioFlinger::OffloadThread::waitingAsyncCallback_l()
+bool OffloadThread::waitingAsyncCallback_l()
 {
     ALOGVV("waitingAsyncCallback_l mWriteAckSequence %d mDrainSequence %d",
           mWriteAckSequence, mDrainSequence);
@@ -7342,13 +7364,13 @@
     return false;
 }
 
-bool AudioFlinger::OffloadThread::waitingAsyncCallback()
+bool OffloadThread::waitingAsyncCallback()
 {
     Mutex::Autolock _l(mLock);
     return waitingAsyncCallback_l();
 }
 
-void AudioFlinger::OffloadThread::flushHw_l()
+void OffloadThread::flushHw_l()
 {
     DirectOutputThread::flushHw_l();
     // Flush anything still waiting in the mixbuffer
@@ -7369,7 +7391,7 @@
     }
 }
 
-void AudioFlinger::OffloadThread::invalidateTracks(audio_stream_type_t streamType)
+void OffloadThread::invalidateTracks(audio_stream_type_t streamType)
 {
     Mutex::Autolock _l(mLock);
     if (PlaybackThread::invalidateTracks_l(streamType)) {
@@ -7377,7 +7399,7 @@
     }
 }
 
-void AudioFlinger::OffloadThread::invalidateTracks(std::set<audio_port_handle_t>& portIds) {
+void OffloadThread::invalidateTracks(std::set<audio_port_handle_t>& portIds) {
     Mutex::Autolock _l(mLock);
     if (PlaybackThread::invalidateTracks_l(portIds)) {
         mFlushPending = true;
@@ -7386,7 +7408,14 @@
 
 // ----------------------------------------------------------------------------
 
-AudioFlinger::DuplicatingThread::DuplicatingThread(const sp<AudioFlinger>& audioFlinger,
+/* static */
+sp<IAfDuplicatingThread> IAfDuplicatingThread::create(
+        const sp<AudioFlinger>& audioFlinger,
+        IAfPlaybackThread* mainThread, audio_io_handle_t id, bool systemReady) {
+    return sp<DuplicatingThread>::make(audioFlinger, mainThread, id, systemReady);
+}
+
+DuplicatingThread::DuplicatingThread(const sp<AudioFlinger>& audioFlinger,
        IAfPlaybackThread* mainThread, audio_io_handle_t id, bool systemReady)
     :   MixerThread(audioFlinger, mainThread->getOutput(), id,
                     systemReady, DUPLICATING),
@@ -7395,14 +7424,14 @@
     addOutputTrack(mainThread);
 }
 
-AudioFlinger::DuplicatingThread::~DuplicatingThread()
+DuplicatingThread::~DuplicatingThread()
 {
     for (size_t i = 0; i < mOutputTracks.size(); i++) {
         mOutputTracks[i]->destroy();
     }
 }
 
-void AudioFlinger::DuplicatingThread::threadLoop_mix()
+void DuplicatingThread::threadLoop_mix()
 {
     // mix buffers...
     if (outputsReady()) {
@@ -7420,7 +7449,7 @@
     mStandbyTimeNs = systemTime() + mStandbyDelayNs;
 }
 
-void AudioFlinger::DuplicatingThread::threadLoop_sleepTime()
+void DuplicatingThread::threadLoop_sleepTime()
 {
     if (mSleepTimeUs == 0) {
         if (mMixerStatus == MIXER_TRACKS_ENABLED) {
@@ -7440,7 +7469,7 @@
     }
 }
 
-ssize_t AudioFlinger::DuplicatingThread::threadLoop_write()
+ssize_t DuplicatingThread::threadLoop_write()
 {
     for (size_t i = 0; i < outputTracks.size(); i++) {
         const ssize_t actualWritten = outputTracks[i]->write(mSinkBuffer, writeFrames);
@@ -7468,7 +7497,7 @@
     return (ssize_t)mSinkBufferSize;
 }
 
-void AudioFlinger::DuplicatingThread::threadLoop_standby()
+void DuplicatingThread::threadLoop_standby()
 {
     // DuplicatingThread implements standby by stopping all tracks
     for (size_t i = 0; i < outputTracks.size(); i++) {
@@ -7476,7 +7505,7 @@
     }
 }
 
-void AudioFlinger::DuplicatingThread::dumpInternals_l(int fd, const Vector<String16>& args)
+void DuplicatingThread::dumpInternals_l(int fd, const Vector<String16>& args)
 {
     MixerThread::dumpInternals_l(fd, args);
 
@@ -7502,17 +7531,17 @@
     write(fd, result.c_str(), result.size());
 }
 
-void AudioFlinger::DuplicatingThread::saveOutputTracks()
+void DuplicatingThread::saveOutputTracks()
 {
     outputTracks = mOutputTracks;
 }
 
-void AudioFlinger::DuplicatingThread::clearOutputTracks()
+void DuplicatingThread::clearOutputTracks()
 {
     outputTracks.clear();
 }
 
-void AudioFlinger::DuplicatingThread::addOutputTrack(IAfPlaybackThread* thread)
+void DuplicatingThread::addOutputTrack(IAfPlaybackThread* thread)
 {
     Mutex::Autolock _l(mLock);
     // The downstream MixerThread consumes thread->frameCount() amount of frames per mix pass.
@@ -7549,7 +7578,7 @@
     updateWaitTime_l();
 }
 
-void AudioFlinger::DuplicatingThread::removeOutputTrack(IAfPlaybackThread* thread)
+void DuplicatingThread::removeOutputTrack(IAfPlaybackThread* thread)
 {
     Mutex::Autolock _l(mLock);
     for (size_t i = 0; i < mOutputTracks.size(); i++) {
@@ -7567,7 +7596,7 @@
 }
 
 // caller must hold mLock
-void AudioFlinger::DuplicatingThread::updateWaitTime_l()
+void DuplicatingThread::updateWaitTime_l()
 {
     mWaitTimeMs = UINT_MAX;
     for (size_t i = 0; i < mOutputTracks.size(); i++) {
@@ -7582,7 +7611,7 @@
     }
 }
 
-bool AudioFlinger::DuplicatingThread::outputsReady()
+bool DuplicatingThread::outputsReady()
 {
     for (size_t i = 0; i < outputTracks.size(); i++) {
         const auto thread = outputTracks[i]->thread().promote();
@@ -7602,7 +7631,7 @@
     return true;
 }
 
-void AudioFlinger::DuplicatingThread::sendMetadataToBackend_l(
+void DuplicatingThread::sendMetadataToBackend_l(
         const StreamOutHalInterface::SourceMetadata& metadata)
 {
     for (auto& outputTrack : outputTracks) { // not mOutputTracks
@@ -7610,12 +7639,12 @@
     }
 }
 
-uint32_t AudioFlinger::DuplicatingThread::activeSleepTimeUs() const
+uint32_t DuplicatingThread::activeSleepTimeUs() const
 {
     return (mWaitTimeMs * 1000) / 2;
 }
 
-void AudioFlinger::DuplicatingThread::cacheParameters_l()
+void DuplicatingThread::cacheParameters_l()
 {
     // updateWaitTime_l() sets mWaitTimeMs, which affects activeSleepTimeUs(), so call it first
     updateWaitTime_l();
@@ -7625,7 +7654,17 @@
 
 // ----------------------------------------------------------------------------
 
-AudioFlinger::SpatializerThread::SpatializerThread(const sp<AudioFlinger>& audioFlinger,
+/* static */
+sp<IAfPlaybackThread> IAfPlaybackThread::createSpatializerThread(
+        const sp<AudioFlinger>& audioFlinger,
+        AudioStreamOut* output,
+        audio_io_handle_t id,
+        bool systemReady,
+        audio_config_base_t* mixerConfig) {
+    return sp<SpatializerThread>::make(audioFlinger, output, id, systemReady, mixerConfig);
+}
+
+SpatializerThread::SpatializerThread(const sp<AudioFlinger>& audioFlinger,
                                                              AudioStreamOut* output,
                                                              audio_io_handle_t id,
                                                              bool systemReady,
@@ -7634,7 +7673,7 @@
 {
 }
 
-void AudioFlinger::SpatializerThread::onFirstRef() {
+void SpatializerThread::onFirstRef() {
     MixerThread::onFirstRef();
 
     const pid_t tid = getTid();
@@ -7649,7 +7688,7 @@
     }
 }
 
-void AudioFlinger::SpatializerThread::setHalLatencyMode_l() {
+void SpatializerThread::setHalLatencyMode_l() {
     // if mSupportedLatencyModes is empty, the HAL stream does not support
     // latency mode control and we can exit.
     if (mSupportedLatencyModes.empty()) {
@@ -7687,7 +7726,7 @@
     }
 }
 
-status_t AudioFlinger::SpatializerThread::setRequestedLatencyMode(audio_latency_mode_t mode) {
+status_t SpatializerThread::setRequestedLatencyMode(audio_latency_mode_t mode) {
     if (mode != AUDIO_LATENCY_MODE_LOW && mode != AUDIO_LATENCY_MODE_FREE) {
         return BAD_VALUE;
     }
@@ -7696,7 +7735,7 @@
     return NO_ERROR;
 }
 
-void AudioFlinger::SpatializerThread::checkOutputStageEffects()
+void SpatializerThread::checkOutputStageEffects()
 {
     bool hasVirtualizer = false;
     bool hasDownMixer = false;
@@ -7756,10 +7795,10 @@
         AudioStreamIn* input,
         audio_io_handle_t id,
         bool systemReady) {
-    return sp<AudioFlinger::RecordThread>::make(audioFlinger, input, id, systemReady);
+    return sp<RecordThread>::make(audioFlinger, input, id, systemReady);
 }
 
-AudioFlinger::RecordThread::RecordThread(const sp<AudioFlinger>& audioFlinger,
+RecordThread::RecordThread(const sp<AudioFlinger>& audioFlinger,
                                          AudioStreamIn *input,
                                          audio_io_handle_t id,
                                          bool systemReady
@@ -7918,7 +7957,7 @@
     // FIXME mNormalSource
 }
 
-AudioFlinger::RecordThread::~RecordThread()
+RecordThread::~RecordThread()
 {
     if (mFastCapture != 0) {
         FastCaptureStateQueue *sq = mFastCapture->sq();
@@ -7940,12 +7979,12 @@
     free(mRsmpInBuffer);
 }
 
-void AudioFlinger::RecordThread::onFirstRef()
+void RecordThread::onFirstRef()
 {
     run(mThreadName, PRIORITY_URGENT_AUDIO);
 }
 
-void AudioFlinger::RecordThread::preExit()
+void RecordThread::preExit()
 {
     ALOGV("  preExit()");
     Mutex::Autolock _l(mLock);
@@ -7957,7 +7996,7 @@
     mStartStopCond.broadcast();
 }
 
-bool AudioFlinger::RecordThread::threadLoop()
+bool RecordThread::threadLoop()
 {
     nsecs_t lastWarning = 0;
 
@@ -8522,7 +8561,7 @@
     return false;
 }
 
-void AudioFlinger::RecordThread::standbyIfNotAlreadyInStandby()
+void RecordThread::standbyIfNotAlreadyInStandby()
 {
     if (!mStandby) {
         inputStandBy();
@@ -8532,7 +8571,7 @@
     }
 }
 
-void AudioFlinger::RecordThread::inputStandBy()
+void RecordThread::inputStandBy()
 {
     // Idle the fast capture if it's currently running
     if (mFastCapture != 0) {
@@ -8573,7 +8612,7 @@
 }
 
 // RecordThread::createRecordTrack_l() must be called with AudioFlinger::mLock held
-sp<IAfRecordTrack> AudioFlinger::RecordThread::createRecordTrack_l(
+sp<IAfRecordTrack> RecordThread::createRecordTrack_l(
         const sp<Client>& client,
         const audio_attributes_t& attr,
         uint32_t *pSampleRate,
@@ -8771,7 +8810,7 @@
     return track;
 }
 
-status_t AudioFlinger::RecordThread::start(IAfRecordTrack* recordTrack,
+status_t RecordThread::start(IAfRecordTrack* recordTrack,
                                            AudioSystem::sync_event_t event,
                                            audio_session_t triggerSession)
 {
@@ -8867,9 +8906,9 @@
     }
 }
 
-void AudioFlinger::RecordThread::syncStartEventCallback(const wp<audioflinger::SyncEvent>& event)
+void RecordThread::syncStartEventCallback(const wp<SyncEvent>& event)
 {
-    sp<audioflinger::SyncEvent> strongEvent = event.promote();
+    const sp<SyncEvent> strongEvent = event.promote();
 
     if (strongEvent != 0) {
         sp<IAfTrackBase> ptr =
@@ -8881,7 +8920,7 @@
     }
 }
 
-bool AudioFlinger::RecordThread::stop(IAfRecordTrack* recordTrack) {
+bool RecordThread::stop(IAfRecordTrack* recordTrack) {
     ALOGV("RecordThread::stop");
     AutoMutex _l(mLock);
     // if we're invalid, we can't be on the ActiveTracks.
@@ -8909,14 +8948,12 @@
     return false;
 }
 
-bool AudioFlinger::RecordThread::isValidSyncEvent(
-        const sp<audioflinger::SyncEvent>& /* event */) const
+bool RecordThread::isValidSyncEvent(const sp<SyncEvent>& /* event */) const
 {
     return false;
 }
 
-status_t AudioFlinger::RecordThread::setSyncEvent(
-        const sp<audioflinger::SyncEvent>& event __unused)
+status_t RecordThread::setSyncEvent(const sp<SyncEvent>& /* event */)
 {
 #if 0   // This branch is currently dead code, but is preserved in case it will be needed in future
     if (!isValidSyncEvent(event)) {
@@ -8941,7 +8978,7 @@
 #endif
 }
 
-status_t AudioFlinger::RecordThread::getActiveMicrophones(
+status_t RecordThread::getActiveMicrophones(
         std::vector<media::MicrophoneInfoFw>* activeMicrophones) const
 {
     ALOGV("RecordThread::getActiveMicrophones");
@@ -8953,7 +8990,7 @@
     return status;
 }
 
-status_t AudioFlinger::RecordThread::setPreferredMicrophoneDirection(
+status_t RecordThread::setPreferredMicrophoneDirection(
             audio_microphone_direction_t direction)
 {
     ALOGV("setPreferredMicrophoneDirection(%d)", direction);
@@ -8964,7 +9001,7 @@
     return mInput->stream->setPreferredMicrophoneDirection(direction);
 }
 
-status_t AudioFlinger::RecordThread::setPreferredMicrophoneFieldDimension(float zoom)
+status_t RecordThread::setPreferredMicrophoneFieldDimension(float zoom)
 {
     ALOGV("setPreferredMicrophoneFieldDimension(%f)", zoom);
     AutoMutex _l(mLock);
@@ -8974,14 +9011,14 @@
     return mInput->stream->setPreferredMicrophoneFieldDimension(zoom);
 }
 
-status_t AudioFlinger::RecordThread::shareAudioHistory(
+status_t RecordThread::shareAudioHistory(
         const std::string& sharedAudioPackageName, audio_session_t sharedSessionId,
         int64_t sharedAudioStartMs) {
     AutoMutex _l(mLock);
     return shareAudioHistory_l(sharedAudioPackageName, sharedSessionId, sharedAudioStartMs);
 }
 
-status_t AudioFlinger::RecordThread::shareAudioHistory_l(
+status_t RecordThread::shareAudioHistory_l(
         const std::string& sharedAudioPackageName, audio_session_t sharedSessionId,
         int64_t sharedAudioStartMs) {
 
@@ -9021,13 +9058,13 @@
     return NO_ERROR;
 }
 
-void AudioFlinger::RecordThread::resetAudioHistory_l() {
+void RecordThread::resetAudioHistory_l() {
     mSharedAudioSessionId = AUDIO_SESSION_NONE;
     mSharedAudioStartFrames = -1;
     mSharedAudioPackageName = "";
 }
 
-AudioFlinger::ThreadBase::MetadataUpdate AudioFlinger::RecordThread::updateMetadata_l()
+ThreadBase::MetadataUpdate RecordThread::updateMetadata_l()
 {
     if (!isStreamInitialized() || !mActiveTracks.readAndClearHasChanged()) {
         return {}; // nothing to do
@@ -9044,7 +9081,7 @@
 }
 
 // destroyTrack_l() must be called with ThreadBase::mLock held
-void AudioFlinger::RecordThread::destroyTrack_l(const sp<IAfRecordTrack>& track)
+void RecordThread::destroyTrack_l(const sp<IAfRecordTrack>& track)
 {
     track->terminate();
     track->setState(IAfTrackBase::STOPPED);
@@ -9055,7 +9092,7 @@
     }
 }
 
-void AudioFlinger::RecordThread::removeTrack_l(const sp<IAfRecordTrack>& track)
+void RecordThread::removeTrack_l(const sp<IAfRecordTrack>& track)
 {
     String8 result;
     track->appendDump(result, false /* active */);
@@ -9069,7 +9106,7 @@
     }
 }
 
-void AudioFlinger::RecordThread::dumpInternals_l(int fd, const Vector<String16>& args __unused)
+void RecordThread::dumpInternals_l(int fd, const Vector<String16>& /* args */)
 {
     AudioStreamIn *input = mInput;
     audio_input_flags_t flags = input != NULL ? input->flags : AUDIO_INPUT_FLAG_NONE;
@@ -9097,7 +9134,7 @@
     copy->dump(fd);
 }
 
-void AudioFlinger::RecordThread::dumpTracks_l(int fd, const Vector<String16>& args __unused)
+void RecordThread::dumpTracks_l(int fd, const Vector<String16>& /* args */)
 {
     String8 result;
     size_t numtracks = mTracks.size();
@@ -9141,7 +9178,7 @@
     write(fd, result.string(), result.size());
 }
 
-void AudioFlinger::RecordThread::setRecordSilenced(audio_port_handle_t portId, bool silenced)
+void RecordThread::setRecordSilenced(audio_port_handle_t portId, bool silenced)
 {
     Mutex::Autolock _l(mLock);
     for (size_t i = 0; i < mTracks.size() ; i++) {
@@ -9155,8 +9192,7 @@
 void ResamplerBufferProvider::reset()
 {
     const auto threadBase = mRecordTrack->thread().promote();
-    auto* const recordThread =
-            static_cast<AudioFlinger::RecordThread *>(threadBase->asIAfRecordThread().get());
+    auto* const recordThread = static_cast<RecordThread *>(threadBase->asIAfRecordThread().get());
     mRsmpInUnrel = 0;
     const int32_t rear = recordThread->mRsmpInRear;
     ssize_t deltaFrames = 0;
@@ -9180,8 +9216,7 @@
         size_t *framesAvailable, bool *hasOverrun)
 {
     const auto threadBase = mRecordTrack->thread().promote();
-    auto* const recordThread =
-            static_cast<AudioFlinger::RecordThread *>(threadBase->asIAfRecordThread().get());
+    auto* const recordThread = static_cast<RecordThread *>(threadBase->asIAfRecordThread().get());
     const int32_t rear = recordThread->mRsmpInRear;
     const int32_t front = mRsmpInFront;
     const ssize_t filled = audio_utils::safe_sub_overflow(rear, front);
@@ -9220,8 +9255,7 @@
         buffer->raw = NULL;
         return NOT_ENOUGH_DATA;
     }
-    auto* const recordThread =
-            static_cast<AudioFlinger::RecordThread *>(threadBase->asIAfRecordThread().get());
+    auto* const recordThread = static_cast<RecordThread *>(threadBase->asIAfRecordThread().get());
     int32_t rear = recordThread->mRsmpInRear;
     int32_t front = mRsmpInFront;
     ssize_t filled = audio_utils::safe_sub_overflow(rear, front);
@@ -9269,13 +9303,13 @@
     buffer->frameCount = 0;
 }
 
-void AudioFlinger::RecordThread::checkBtNrec()
+void RecordThread::checkBtNrec()
 {
     Mutex::Autolock _l(mLock);
     checkBtNrec_l();
 }
 
-void AudioFlinger::RecordThread::checkBtNrec_l()
+void RecordThread::checkBtNrec_l()
 {
     // disable AEC and NS if the device is a BT SCO headset supporting those
     // pre processings
@@ -9290,7 +9324,7 @@
 }
 
 
-bool AudioFlinger::RecordThread::checkForNewParameter_l(const String8& keyValuePair,
+bool RecordThread::checkForNewParameter_l(const String8& keyValuePair,
                                                         status_t& status)
 {
     bool reconfig = false;
@@ -9378,7 +9412,7 @@
     return reconfig;
 }
 
-String8 AudioFlinger::RecordThread::getParameters(const String8& keys)
+String8 RecordThread::getParameters(const String8& keys)
 {
     Mutex::Autolock _l(mLock);
     if (initCheck() == NO_ERROR) {
@@ -9390,7 +9424,7 @@
     return {};
 }
 
-void AudioFlinger::RecordThread::ioConfigChanged(audio_io_config_event_t event, pid_t pid,
+void RecordThread::ioConfigChanged(audio_io_config_event_t event, pid_t pid,
                                                  audio_port_handle_t portId) {
     sp<AudioIoDescriptor> desc;
     switch (event) {
@@ -9411,7 +9445,7 @@
     mAudioFlinger->ioConfigChanged(event, desc, pid);
 }
 
-void AudioFlinger::RecordThread::readInputParameters_l()
+void RecordThread::readInputParameters_l()
 {
     status_t result = mInput->stream->getAudioProperties(&mSampleRate, &mChannelMask, &mHALFormat);
     LOG_ALWAYS_FATAL_IF(result != OK, "Error retrieving audio properties from HAL: %d", result);
@@ -9454,7 +9488,7 @@
         .record();
 }
 
-uint32_t AudioFlinger::RecordThread::getInputFramesLost() const
+uint32_t RecordThread::getInputFramesLost() const
 {
     Mutex::Autolock _l(mLock);
     uint32_t result;
@@ -9464,7 +9498,7 @@
     return 0;
 }
 
-KeyedVector<audio_session_t, bool> AudioFlinger::RecordThread::sessionIds() const
+KeyedVector<audio_session_t, bool> RecordThread::sessionIds() const
 {
     KeyedVector<audio_session_t, bool> ids;
     Mutex::Autolock _l(mLock);
@@ -9478,7 +9512,7 @@
     return ids;
 }
 
-AudioStreamIn* AudioFlinger::RecordThread::clearInput()
+AudioStreamIn* RecordThread::clearInput()
 {
     Mutex::Autolock _l(mLock);
     AudioStreamIn *input = mInput;
@@ -9487,7 +9521,7 @@
 }
 
 // this method must always be called either with ThreadBase mLock held or inside the thread loop
-sp<StreamHalInterface> AudioFlinger::RecordThread::stream() const
+sp<StreamHalInterface> RecordThread::stream() const
 {
     if (mInput == NULL) {
         return NULL;
@@ -9495,7 +9529,7 @@
     return mInput->stream;
 }
 
-status_t AudioFlinger::RecordThread::addEffectChain_l(const sp<IAfEffectChain>& chain)
+status_t RecordThread::addEffectChain_l(const sp<IAfEffectChain>& chain)
 {
     ALOGV("addEffectChain_l() %p on thread %p", chain.get(), this);
     chain->setThread(this);
@@ -9513,7 +9547,7 @@
     return NO_ERROR;
 }
 
-size_t AudioFlinger::RecordThread::removeEffectChain_l(const sp<IAfEffectChain>& chain)
+size_t RecordThread::removeEffectChain_l(const sp<IAfEffectChain>& chain)
 {
     ALOGV("removeEffectChain_l() %p from thread %p", chain.get(), this);
 
@@ -9526,7 +9560,7 @@
     return mEffectChains.size();
 }
 
-status_t AudioFlinger::RecordThread::createAudioPatch_l(const struct audio_patch *patch,
+status_t RecordThread::createAudioPatch_l(const struct audio_patch* patch,
                                                           audio_patch_handle_t *handle)
 {
     status_t status = NO_ERROR;
@@ -9583,7 +9617,7 @@
     return status;
 }
 
-status_t AudioFlinger::RecordThread::releaseAudioPatch_l(const audio_patch_handle_t handle)
+status_t RecordThread::releaseAudioPatch_l(const audio_patch_handle_t handle)
 {
     status_t status = NO_ERROR;
 
@@ -9602,7 +9636,7 @@
     return status;
 }
 
-void AudioFlinger::RecordThread::updateOutDevices(const DeviceDescriptorBaseVector& outDevices)
+void RecordThread::updateOutDevices(const DeviceDescriptorBaseVector& outDevices)
 {
     Mutex::Autolock _l(mLock);
     mOutDevices = outDevices;
@@ -9612,7 +9646,7 @@
     }
 }
 
-int32_t AudioFlinger::RecordThread::getOldestFront_l()
+int32_t RecordThread::getOldestFront_l()
 {
     if (mTracks.size() == 0) {
         return mRsmpInRear;
@@ -9634,7 +9668,7 @@
     return oldestFront;
 }
 
-void AudioFlinger::RecordThread::updateFronts_l(int32_t offset)
+void RecordThread::updateFronts_l(int32_t offset)
 {
     if (offset == 0) {
         return;
@@ -9646,7 +9680,7 @@
     }
 }
 
-void AudioFlinger::RecordThread::resizeInputBuffer_l(int32_t maxSharedAudioHistoryMs)
+void RecordThread::resizeInputBuffer_l(int32_t maxSharedAudioHistoryMs)
 {
     // This is the formula for calculating the temporary buffer size.
     // With 7 HAL buffers, we can guarantee ability to down-sample the input by ratio of 6:1 to
@@ -9670,7 +9704,7 @@
     mRsmpInRear = 0;
 
     ALOG_ASSERT(maxSharedAudioHistoryMs >= 0
-            && maxSharedAudioHistoryMs <= AudioFlinger::kMaxSharedAudioHistoryMs,
+            && maxSharedAudioHistoryMs <= kMaxSharedAudioHistoryMs,
             "resizeInputBuffer_l() called with invalid max shared history %d",
             maxSharedAudioHistoryMs);
     if (maxSharedAudioHistoryMs != 0) {
@@ -9739,7 +9773,7 @@
     mRsmpInBuffer = rsmpInBuffer;
 }
 
-void AudioFlinger::RecordThread::addPatchTrack(const sp<IAfPatchRecord>& record)
+void RecordThread::addPatchTrack(const sp<IAfPatchRecord>& record)
 {
     Mutex::Autolock _l(mLock);
     mTracks.add(record);
@@ -9748,7 +9782,7 @@
     }
 }
 
-void AudioFlinger::RecordThread::deletePatchTrack(const sp<IAfPatchRecord>& record)
+void RecordThread::deletePatchTrack(const sp<IAfPatchRecord>& record)
 {
     Mutex::Autolock _l(mLock);
     if (mSource == record->getSource()) {
@@ -9757,7 +9791,7 @@
     destroyTrack_l(record);
 }
 
-void AudioFlinger::RecordThread::toAudioPortConfig(struct audio_port_config *config)
+void RecordThread::toAudioPortConfig(struct audio_port_config* config)
 {
     ThreadBase::toAudioPortConfig(config);
     config->role = AUDIO_PORT_ROLE_SINK;
@@ -9851,7 +9885,7 @@
 }
 
 
-AudioFlinger::MmapThread::MmapThread(
+MmapThread::MmapThread(
         const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id,
         AudioHwDevice *hwDev, const sp<StreamHalInterface>& stream, bool systemReady, bool isOut)
     : ThreadBase(audioFlinger, id, (isOut ? MMAP_PLAYBACK : MMAP_CAPTURE), systemReady, isOut),
@@ -9866,16 +9900,12 @@
     readHalParameters_l();
 }
 
-AudioFlinger::MmapThread::~MmapThread()
-{
-}
-
-void AudioFlinger::MmapThread::onFirstRef()
+void MmapThread::onFirstRef()
 {
     run(mThreadName, ANDROID_PRIORITY_URGENT_AUDIO);
 }
 
-void AudioFlinger::MmapThread::disconnect()
+void MmapThread::disconnect()
 {
     ActiveTracks<IAfMmapTrack> activeTracks;
     {
@@ -9896,7 +9926,7 @@
 }
 
 
-void AudioFlinger::MmapThread::configure(const audio_attributes_t *attr,
+void MmapThread::configure(const audio_attributes_t* attr,
                                                 audio_stream_type_t streamType __unused,
                                                 audio_session_t sessionId,
                                                 const sp<MmapStreamCallback>& callback,
@@ -9910,7 +9940,7 @@
     mPortId = portId;
 }
 
-status_t AudioFlinger::MmapThread::createMmapBuffer(int32_t minSizeFrames,
+status_t MmapThread::createMmapBuffer(int32_t minSizeFrames,
                                   struct audio_mmap_buffer_info *info)
 {
     if (mHalStream == 0) {
@@ -9920,7 +9950,7 @@
     return mHalStream->createMmapBuffer(minSizeFrames, info);
 }
 
-status_t AudioFlinger::MmapThread::getMmapPosition(struct audio_mmap_position* position) const
+status_t MmapThread::getMmapPosition(struct audio_mmap_position* position) const
 {
     if (mHalStream == 0) {
         return NO_INIT;
@@ -9928,7 +9958,7 @@
     return mHalStream->getMmapPosition(position);
 }
 
-status_t AudioFlinger::MmapThread::exitStandby_l()
+status_t MmapThread::exitStandby_l()
 {
     // The HAL must receive track metadata before starting the stream
     updateMetadata_l();
@@ -9945,7 +9975,7 @@
     return NO_ERROR;
 }
 
-status_t AudioFlinger::MmapThread::start(const AudioClient& client,
+status_t MmapThread::start(const AudioClient& client,
                                          const audio_attributes_t *attr,
                                          audio_port_handle_t *handle)
 {
@@ -10092,7 +10122,7 @@
     return ret;
 }
 
-status_t AudioFlinger::MmapThread::stop(audio_port_handle_t handle)
+status_t MmapThread::stop(audio_port_handle_t handle)
 {
     ALOGV("%s handle %d", __FUNCTION__, handle);
 
@@ -10146,7 +10176,7 @@
     return NO_ERROR;
 }
 
-status_t AudioFlinger::MmapThread::standby()
+status_t MmapThread::standby()
 {
     ALOGV("%s", __FUNCTION__);
 
@@ -10166,12 +10196,12 @@
     return NO_ERROR;
 }
 
-status_t AudioFlinger::MmapThread::reportData(const void* /*buffer*/, size_t /*frameCount*/) {
+status_t MmapThread::reportData(const void* /*buffer*/, size_t /*frameCount*/) {
     // This is a stub implementation. The MmapPlaybackThread overrides this function.
     return INVALID_OPERATION;
 }
 
-void AudioFlinger::MmapThread::readHalParameters_l()
+void MmapThread::readHalParameters_l()
 {
     status_t result = mHalStream->getAudioProperties(&mSampleRate, &mChannelMask, &mHALFormat);
     LOG_ALWAYS_FATAL_IF(result != OK, "Error retrieving audio properties from HAL: %d", result);
@@ -10207,7 +10237,7 @@
         .record();
 }
 
-bool AudioFlinger::MmapThread::threadLoop()
+bool MmapThread::threadLoop()
 {
     checkSilentMode_l();
 
@@ -10278,7 +10308,7 @@
 }
 
 // checkForNewParameter_l() must be called with ThreadBase::mLock held
-bool AudioFlinger::MmapThread::checkForNewParameter_l(const String8& keyValuePair,
+bool MmapThread::checkForNewParameter_l(const String8& keyValuePair,
                                                               status_t& status)
 {
     AudioParameter param = AudioParameter(keyValuePair);
@@ -10296,7 +10326,7 @@
     return false;
 }
 
-String8 AudioFlinger::MmapThread::getParameters(const String8& keys)
+String8 MmapThread::getParameters(const String8& keys)
 {
     Mutex::Autolock _l(mLock);
     String8 out_s8;
@@ -10306,7 +10336,7 @@
     return {};
 }
 
-void AudioFlinger::MmapThread::ioConfigChanged(audio_io_config_event_t event, pid_t pid,
+void MmapThread::ioConfigChanged(audio_io_config_event_t event, pid_t pid,
                                                audio_port_handle_t portId __unused) {
     sp<AudioIoDescriptor> desc;
     bool isInput = false;
@@ -10331,7 +10361,7 @@
     mAudioFlinger->ioConfigChanged(event, desc, pid);
 }
 
-status_t AudioFlinger::MmapThread::createAudioPatch_l(const struct audio_patch *patch,
+status_t MmapThread::createAudioPatch_l(const struct audio_patch* patch,
                                                           audio_patch_handle_t *handle)
 NO_THREAD_SAFETY_ANALYSIS  // elease and re-acquire mLock
 {
@@ -10422,7 +10452,7 @@
     return status;
 }
 
-status_t AudioFlinger::MmapThread::releaseAudioPatch_l(const audio_patch_handle_t handle)
+status_t MmapThread::releaseAudioPatch_l(const audio_patch_handle_t handle)
 {
     status_t status = NO_ERROR;
 
@@ -10444,7 +10474,7 @@
     return status;
 }
 
-void AudioFlinger::MmapThread::toAudioPortConfig(struct audio_port_config *config)
+void MmapThread::toAudioPortConfig(struct audio_port_config* config)
 {
     ThreadBase::toAudioPortConfig(config);
     if (isOutput()) {
@@ -10458,7 +10488,7 @@
     }
 }
 
-status_t AudioFlinger::MmapThread::addEffectChain_l(const sp<IAfEffectChain>& chain)
+status_t MmapThread::addEffectChain_l(const sp<IAfEffectChain>& chain)
 {
     audio_session_t session = chain->sessionId();
 
@@ -10482,7 +10512,7 @@
     return NO_ERROR;
 }
 
-size_t AudioFlinger::MmapThread::removeEffectChain_l(const sp<IAfEffectChain>& chain)
+size_t MmapThread::removeEffectChain_l(const sp<IAfEffectChain>& chain)
 {
     audio_session_t session = chain->sessionId();
 
@@ -10505,29 +10535,29 @@
     return mEffectChains.size();
 }
 
-void AudioFlinger::MmapThread::threadLoop_standby()
+void MmapThread::threadLoop_standby()
 {
     mHalStream->standby();
 }
 
-void AudioFlinger::MmapThread::threadLoop_exit()
+void MmapThread::threadLoop_exit()
 {
     // Do not call callback->onTearDown() because it is redundant for thread exit
     // and because it can cause a recursive mutex lock on stop().
 }
 
-status_t AudioFlinger::MmapThread::setSyncEvent(const sp<audioflinger::SyncEvent>& /* event */)
+status_t MmapThread::setSyncEvent(const sp<SyncEvent>& /* event */)
 {
     return BAD_VALUE;
 }
 
-bool AudioFlinger::MmapThread::isValidSyncEvent(
-        const sp<audioflinger::SyncEvent>& /* event */) const
+bool MmapThread::isValidSyncEvent(
+        const sp<SyncEvent>& /* event */) const
 {
     return false;
 }
 
-status_t AudioFlinger::MmapThread::checkEffectCompatibility_l(
+status_t MmapThread::checkEffectCompatibility_l(
         const effect_descriptor_t *desc, audio_session_t sessionId)
 {
     // No global effect sessions on mmap threads
@@ -10561,7 +10591,7 @@
     return NO_ERROR;
 }
 
-void AudioFlinger::MmapThread::checkInvalidTracks_l()
+void MmapThread::checkInvalidTracks_l()
 NO_THREAD_SAFETY_ANALYSIS  // release and re-acquire mLock
 {
     sp<MmapStreamCallback> callback;
@@ -10582,7 +10612,7 @@
     }
 }
 
-void AudioFlinger::MmapThread::dumpInternals_l(int fd, const Vector<String16>& args __unused)
+void MmapThread::dumpInternals_l(int fd, const Vector<String16>& /* args */)
 {
     dprintf(fd, "  Attributes: content type %d usage %d source %d\n",
             mAttr.content_type, mAttr.usage, mAttr.source);
@@ -10592,7 +10622,7 @@
     }
 }
 
-void AudioFlinger::MmapThread::dumpTracks_l(int fd, const Vector<String16>& args __unused)
+void MmapThread::dumpTracks_l(int fd, const Vector<String16>& /* args */)
 {
     String8 result;
     size_t numtracks = mActiveTracks.size();
@@ -10612,7 +10642,14 @@
     write(fd, result.string(), result.size());
 }
 
-AudioFlinger::MmapPlaybackThread::MmapPlaybackThread(
+/* static */
+sp<IAfMmapPlaybackThread> IAfMmapPlaybackThread::create(
+        const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id,
+        AudioHwDevice* hwDev,  AudioStreamOut* output, bool systemReady) {
+    return sp<MmapPlaybackThread>::make(audioFlinger, id, hwDev, output, systemReady);
+}
+
+MmapPlaybackThread::MmapPlaybackThread(
         const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id,
         AudioHwDevice *hwDev,  AudioStreamOut *output, bool systemReady)
     : MmapThread(audioFlinger, id, hwDev, output->stream, systemReady, true /* isOut */),
@@ -10646,7 +10683,7 @@
     }
 }
 
-void AudioFlinger::MmapPlaybackThread::configure(const audio_attributes_t *attr,
+void MmapPlaybackThread::configure(const audio_attributes_t* attr,
                                                 audio_stream_type_t streamType,
                                                 audio_session_t sessionId,
                                                 const sp<MmapStreamCallback>& callback,
@@ -10657,7 +10694,7 @@
     mStreamType = streamType;
 }
 
-AudioStreamOut* AudioFlinger::MmapPlaybackThread::clearOutput()
+AudioStreamOut* MmapPlaybackThread::clearOutput()
 {
     Mutex::Autolock _l(mLock);
     AudioStreamOut *output = mOutput;
@@ -10665,7 +10702,7 @@
     return output;
 }
 
-void AudioFlinger::MmapPlaybackThread::setMasterVolume(float value)
+void MmapPlaybackThread::setMasterVolume(float value)
 {
     Mutex::Autolock _l(mLock);
     // Don't apply master volume in SW if our HAL can do it for us.
@@ -10677,7 +10714,7 @@
     }
 }
 
-void AudioFlinger::MmapPlaybackThread::setMasterMute(bool muted)
+void MmapPlaybackThread::setMasterMute(bool muted)
 {
     Mutex::Autolock _l(mLock);
     // Don't apply master mute in SW if our HAL can do it for us.
@@ -10688,7 +10725,7 @@
     }
 }
 
-void AudioFlinger::MmapPlaybackThread::setStreamVolume(audio_stream_type_t stream, float value)
+void MmapPlaybackThread::setStreamVolume(audio_stream_type_t stream, float value)
 {
     Mutex::Autolock _l(mLock);
     mStreamTypes[stream].volume = value;
@@ -10697,13 +10734,13 @@
     }
 }
 
-float AudioFlinger::MmapPlaybackThread::streamVolume(audio_stream_type_t stream) const
+float MmapPlaybackThread::streamVolume(audio_stream_type_t stream) const
 {
     Mutex::Autolock _l(mLock);
     return mStreamTypes[stream].volume;
 }
 
-void AudioFlinger::MmapPlaybackThread::setStreamMute(audio_stream_type_t stream, bool muted)
+void MmapPlaybackThread::setStreamMute(audio_stream_type_t stream, bool muted)
 {
     Mutex::Autolock _l(mLock);
     mStreamTypes[stream].mute = muted;
@@ -10712,7 +10749,7 @@
     }
 }
 
-void AudioFlinger::MmapPlaybackThread::invalidateTracks(audio_stream_type_t streamType)
+void MmapPlaybackThread::invalidateTracks(audio_stream_type_t streamType)
 {
     Mutex::Autolock _l(mLock);
     if (streamType == mStreamType) {
@@ -10723,7 +10760,7 @@
     }
 }
 
-void AudioFlinger::MmapPlaybackThread::invalidateTracks(std::set<audio_port_handle_t>& portIds)
+void MmapPlaybackThread::invalidateTracks(std::set<audio_port_handle_t>& portIds)
 {
     Mutex::Autolock _l(mLock);
     bool trackMatch = false;
@@ -10742,7 +10779,7 @@
     }
 }
 
-void AudioFlinger::MmapPlaybackThread::processVolume_l()
+void MmapPlaybackThread::processVolume_l()
 NO_THREAD_SAFETY_ANALYSIS // access of track->processMuteEvent_l
 {
     float volume;
@@ -10797,7 +10834,7 @@
     }
 }
 
-AudioFlinger::ThreadBase::MetadataUpdate AudioFlinger::MmapPlaybackThread::updateMetadata_l()
+ThreadBase::MetadataUpdate MmapPlaybackThread::updateMetadata_l()
 {
     if (!isStreamInitialized() || !mActiveTracks.readAndClearHasChanged()) {
         return {}; // nothing to do
@@ -10822,7 +10859,7 @@
     return change;
 };
 
-void AudioFlinger::MmapPlaybackThread::checkSilentMode_l()
+void MmapPlaybackThread::checkSilentMode_l()
 {
     if (!mMasterMute) {
         char value[PROPERTY_VALUE_MAX];
@@ -10839,7 +10876,7 @@
     }
 }
 
-void AudioFlinger::MmapPlaybackThread::toAudioPortConfig(struct audio_port_config *config)
+void MmapPlaybackThread::toAudioPortConfig(struct audio_port_config* config)
 {
     MmapThread::toAudioPortConfig(config);
     if (mOutput && mOutput->flags != AUDIO_OUTPUT_FLAG_NONE) {
@@ -10848,7 +10885,7 @@
     }
 }
 
-status_t AudioFlinger::MmapPlaybackThread::getExternalPosition(uint64_t *position,
+status_t MmapPlaybackThread::getExternalPosition(uint64_t* position,
         int64_t* timeNanos) const
 {
     if (mOutput == nullptr) {
@@ -10862,7 +10899,7 @@
     return status;
 }
 
-status_t AudioFlinger::MmapPlaybackThread::reportData(const void* buffer, size_t frameCount) {
+status_t MmapPlaybackThread::reportData(const void* buffer, size_t frameCount) {
     // Send to MelProcessor for sound dose measurement.
     auto processor = mMelProcessor.load();
     if (processor) {
@@ -10873,7 +10910,7 @@
 }
 
 // startMelComputation_l() must be called with AudioFlinger::mLock held
-void AudioFlinger::MmapPlaybackThread::startMelComputation_l(
+void MmapPlaybackThread::startMelComputation_l(
         const sp<audio_utils::MelProcessor>& processor)
 {
     ALOGV("%s: starting mel processor for thread %d", __func__, id());
@@ -10887,7 +10924,7 @@
 }
 
 // stopMelComputation_l() must be called with AudioFlinger::mLock held
-void AudioFlinger::MmapPlaybackThread::stopMelComputation_l()
+void MmapPlaybackThread::stopMelComputation_l()
 {
     ALOGV("%s: pausing mel processor for thread %d", __func__, id());
     auto melProcessor = mMelProcessor.load();
@@ -10896,7 +10933,7 @@
     }
 }
 
-void AudioFlinger::MmapPlaybackThread::dumpInternals_l(int fd, const Vector<String16>& args)
+void MmapPlaybackThread::dumpInternals_l(int fd, const Vector<String16>& args)
 {
     MmapThread::dumpInternals_l(fd, args);
 
@@ -10905,7 +10942,14 @@
     dprintf(fd, "  Master volume: %f Master mute %d\n", mMasterVolume, mMasterMute);
 }
 
-AudioFlinger::MmapCaptureThread::MmapCaptureThread(
+/* static */
+sp<IAfMmapCaptureThread> IAfMmapCaptureThread::create(
+        const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id,
+        AudioHwDevice* hwDev,  AudioStreamIn* input, bool systemReady) {
+    return sp<MmapCaptureThread>::make(audioFlinger, id, hwDev, input, systemReady);
+}
+
+MmapCaptureThread::MmapCaptureThread(
         const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id,
         AudioHwDevice *hwDev,  AudioStreamIn *input, bool systemReady)
     : MmapThread(audioFlinger, id, hwDev, input->stream, systemReady, false /* isOut */),
@@ -10915,7 +10959,7 @@
     mChannelCount = audio_channel_count_from_in_mask(mChannelMask);
 }
 
-status_t AudioFlinger::MmapCaptureThread::exitStandby_l()
+status_t MmapCaptureThread::exitStandby_l()
 {
     {
         // mInput might have been cleared by clearInput()
@@ -10926,7 +10970,7 @@
     return MmapThread::exitStandby_l();
 }
 
-AudioStreamIn* AudioFlinger::MmapCaptureThread::clearInput()
+AudioStreamIn* MmapCaptureThread::clearInput()
 {
     Mutex::Autolock _l(mLock);
     AudioStreamIn *input = mInput;
@@ -10934,7 +10978,7 @@
     return input;
 }
 
-void AudioFlinger::MmapCaptureThread::processVolume_l()
+void MmapCaptureThread::processVolume_l()
 {
     bool changed = false;
     bool silenced = false;
@@ -10961,7 +11005,7 @@
     }
 }
 
-AudioFlinger::ThreadBase::MetadataUpdate AudioFlinger::MmapCaptureThread::updateMetadata_l()
+ThreadBase::MetadataUpdate MmapCaptureThread::updateMetadata_l()
 {
     if (!isStreamInitialized() || !mActiveTracks.readAndClearHasChanged()) {
         return {}; // nothing to do
@@ -10984,7 +11028,7 @@
     return change;
 }
 
-void AudioFlinger::MmapCaptureThread::setRecordSilenced(audio_port_handle_t portId, bool silenced)
+void MmapCaptureThread::setRecordSilenced(audio_port_handle_t portId, bool silenced)
 {
     Mutex::Autolock _l(mLock);
     for (size_t i = 0; i < mActiveTracks.size() ; i++) {
@@ -10996,7 +11040,7 @@
     setClientSilencedIfExists_l(portId, silenced);
 }
 
-void AudioFlinger::MmapCaptureThread::toAudioPortConfig(struct audio_port_config *config)
+void MmapCaptureThread::toAudioPortConfig(struct audio_port_config* config)
 {
     MmapThread::toAudioPortConfig(config);
     if (mInput && mInput->flags != AUDIO_INPUT_FLAG_NONE) {
@@ -11005,7 +11049,7 @@
     }
 }
 
-status_t AudioFlinger::MmapCaptureThread::getExternalPosition(
+status_t MmapCaptureThread::getExternalPosition(
         uint64_t* position, int64_t* timeNanos) const
 {
     if (mInput == nullptr) {
@@ -11016,11 +11060,18 @@
 
 // ----------------------------------------------------------------------------
 
-AudioFlinger::BitPerfectThread::BitPerfectThread(const sp<AudioFlinger> &audioflinger,
+/* static */
+sp<IAfPlaybackThread> IAfPlaybackThread::createBitPerfectThread(
+        const sp<AudioFlinger>& audioflinger,
+        AudioStreamOut* output, audio_io_handle_t id, bool systemReady) {
+    return sp<BitPerfectThread>::make(audioflinger, output, id, systemReady);
+}
+
+BitPerfectThread::BitPerfectThread(const sp<AudioFlinger> &audioflinger,
         AudioStreamOut *output, audio_io_handle_t id, bool systemReady)
         : MixerThread(audioflinger, output, id, systemReady, BIT_PERFECT) {}
 
-AudioFlinger::PlaybackThread::mixer_state AudioFlinger::BitPerfectThread::prepareTracks_l(
+PlaybackThread::mixer_state BitPerfectThread::prepareTracks_l(
         Vector<sp<IAfTrack>>* tracksToRemove) {
     mixer_state result = MixerThread::prepareTracks_l(tracksToRemove);
     // If there is only one active track and it is bit-perfect, enable tee buffer.
@@ -11053,7 +11104,7 @@
     return result;
 }
 
-void AudioFlinger::BitPerfectThread::threadLoop_mix() {
+void BitPerfectThread::threadLoop_mix() {
     MixerThread::threadLoop_mix();
     mHasDataCopiedToSinkBuffer = mIsBitPerfect;
 }
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 4454365..827445a 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -15,11 +15,9 @@
 ** limitations under the License.
 */
 
-#ifndef INCLUDING_FROM_AUDIOFLINGER_H
-    #error This header file should only be included from AudioFlinger.h
-#endif
+#pragma once
 
-public: // TODO(b/288339104) extract out of AudioFlinger class
+namespace android {
 
 class AsyncCallbackThread;
 
@@ -857,15 +855,18 @@
     virtual     void        onDrainReady();
     virtual     void        onError();
 
+public: // AsyncCallbackThread
                 void        resetWriteBlocked(uint32_t sequence);
                 void        resetDraining(uint32_t sequence);
+protected:
 
     virtual     bool        waitingAsyncCallback();
     virtual     bool        waitingAsyncCallback_l();
     virtual     bool        shouldStandby_l();
     virtual     void        onAddNewTrack_l();
+public:  // AsyncCallbackThread
                 void        onAsyncError(); // error reported by AsyncCallbackThread
-
+protected:
     // StreamHalInterfaceCodecFormatCallback implementation
                 void        onCodecFormatChanged(
             const std::basic_string<uint8_t>& metadataBs) final;
@@ -1181,7 +1182,6 @@
 
     audio_channel_mask_t            mMixerChannelMask = AUDIO_CHANNEL_NONE;
 
-private:
     // mMasterMute is in both PlaybackThread and in AudioFlinger.  When a
     // PlaybackThread needs to find out if master-muted, it checks it's local
     // copy rather than the one in AudioFlinger.  This optimization saves a lock.
@@ -1195,7 +1195,6 @@
                             : mTimestampVerifier.DISCONTINUITY_MODE_CONTINUOUS;
                 }
 
-protected:
     ActiveTracks<IAfTrack> mActiveTracks;
 
     // Time to sleep between cycles when:
@@ -1235,8 +1234,6 @@
                                 ThreadBase::invalidateTracksForAudioSession_l(sessionId, mTracks);
                             }
 
-private:
-
     friend class AudioFlinger;      // for numerous
 
     DISALLOW_COPY_AND_ASSIGN(PlaybackThread);
@@ -1305,6 +1302,7 @@
     Tracks<IAfTrack>                   mTracks;
 
     stream_type_t                   mStreamTypes[AUDIO_STREAM_CNT];
+
     AudioStreamOut                  *mOutput;
 
     float                           mMasterVolume;
@@ -1359,19 +1357,20 @@
     // Bit 0 is reset by the async callback thread calling resetDraining(). Out of sequence
     // callbacks are ignored.
     uint32_t                        mDrainSequence;
+
     sp<AsyncCallbackThread>         mCallbackThread;
 
     Mutex                                    mAudioTrackCbLock;
     // Record of IAudioTrackCallback
     std::map<sp<IAfTrack>, sp<media::IAudioTrackCallback>> mAudioTrackCallbacks;
 
-private:
     // The HAL output sink is treated as non-blocking, but current implementation is blocking
     sp<NBAIO_Sink>          mOutputSink;
     // If a fast mixer is present, the blocking pipe sink, otherwise clear
     sp<NBAIO_Sink>          mPipeSink;
     // The current sink for the normal mixer to write it's (sub)mix, mOutputSink or mPipeSink
     sp<NBAIO_Sink>          mNormalSink;
+
     uint32_t                mScreenState;   // cached copy of gScreenState
     // TODO: add comment and adjust size as needed
     static const size_t     kFastMixerLogSize = 8 * 1024;
@@ -1684,11 +1683,8 @@
 
 class AsyncCallbackThread : public Thread {
 public:
-
     explicit AsyncCallbackThread(const wp<PlaybackThread>& playbackThread);
 
-    virtual             ~AsyncCallbackThread();
-
     // Thread virtuals
     virtual bool        threadLoop();
 
@@ -2047,7 +2043,6 @@
     MmapThread(const sp<AudioFlinger>& audioFlinger, audio_io_handle_t id,
                AudioHwDevice *hwDev, const sp<StreamHalInterface>& stream, bool systemReady,
                bool isOut);
-    ~MmapThread() override;
 
     void configure(const audio_attributes_t* attr,
                                       audio_stream_type_t streamType,
@@ -2282,4 +2277,4 @@
     float mVolumeRight = 0.f;
 };
 
-private:
+} // namespace android
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index e838076..6cb3d34 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -637,7 +637,7 @@
     if (mHasOpPlayAudio.compare_exchange_strong(shouldChange, hasAppOps)) {
         ALOGD("OpPlayAudio: track:%d usage:%d %smuted", mId, mUsage, hasAppOps ? "not " : "");
         auto thread = mThread.promote();
-        if (thread != nullptr && thread->type() == AudioFlinger::ThreadBase::OFFLOAD) {
+        if (thread != nullptr && thread->type() == IAfThreadBase::OFFLOAD) {
             // Wake up Thread if offloaded, otherwise it may be several seconds for update.
             Mutex::Autolock _l(thread->mutex());
             thread->broadcast_l();